Rubber Product Failure (Rapra Review Reports)

Report 147

ISSN: 0889-3144

Rubber Product Failure

Roger P. Brown

Volume 13, Number 3, 2002

Rapra Review Reports Expert overviews covering the science and technology of rubber and plastics

RAPRA REVIEW REPORTS A Rapra Review Report comprises three sections, as follows: 1. A commissioned expert review, discussing a key topic of current interest, and referring to the References and Abstracts section. Reference numbers in brackets refer to item numbers from the References and Abstracts section. Where it has been necessary for completeness to cite sources outside the scope of the Rapra Abstracts database, these are listed at the end of the review, and cited in the text as a.1, a.2, etc. 2. A comprehensive References and Abstracts section, resulting from a search of the Rapra Abstracts database. The format of the abstracts is outlined in the sample record below. 3. An index to the References and Abstracts section, derived from the indexing terms which are added to the abstracts records on the database to aid retrieval.

Source of original article Title

Item 1 Macromolecules

33, No.6, 21st March 2000, p.2171-83 EFFECT OF THERMAL HISTORY ON THE RHEOLOGICAL BEHAVIOR OF THERMOPLASTIC POLYURETHANES Pil Joong Yoon; Chang Dae Han Akron,University The effect of thermal history on the rheological behaviour of ester- and ether-based commercial thermoplastic PUs (Estane 5701, 5707 and 5714 from B.F.Goodrich) was investigated. It was found that the injection moulding temp. used for specimen preparation had a marked effect on the variations of dynamic storage and loss moduli of specimens with time observed during isothermal annealing. Analysis of FTIR spectra indicated that variations in hydrogen bonding with time during isothermal annealing very much resembled variations of dynamic storage modulus with time during isothermal annealing. Isochronal dynamic temp. sweep experiments indicated that the thermoplastic PUs exhibited a hysteresis effect in the heating and cooling processes. It was concluded that the microphase separation transition or order-disorder transition in thermoplastic PUs could not be determined from the isochronal dynamic temp. sweep experiment. The plots of log dynamic storage modulus versus log loss modulus varied with temp. over the entire range of temps. (110-190C) investigated. 57 refs.

Location

GOODRICH B.F. USA

Authors and affiliation

Abstract

Companies or organisations mentioned

Accession no.771897

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Materials Handling in the Polymer Industry, H. Hardy, Chronos Richardson Ltd.

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Electronics Applications of Polymers, M.T.Goosey, Plessey Research (Caswell) Ltd.

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Weathering of Polymers, S.M. Halliwell, Building Research Establishment.

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Offshore Applications of Polymers, J.W.Brockbank, Avon Industrial Polymers Ltd.

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Health and Safety in the Rubber Industry, A.R. Nutt, Arnold Nutt & Co. and J. Wade.

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Recent Developments in Materials for Food Packaging, R.A. Roberts, Pira Packaging Division.

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Computer Modelling of Polymer Processing, E. Andreassen, Å. Larsen and E.L. Hinrichsen, Senter for Industriforskning, Norway.

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Plastics in High Temperature Applications, J. Maxwell, Consultant.

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Joining of Plastics, K.W. Allen, City University.

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Physical Testing of Rubber, R.P. Brown, Rapra Technology Ltd.

Report 59

Polyimides - Materials, Processing and Applications, A.J. Kirby, Du Pont (U.K.) Ltd. Physical Testing of Thermoplastics, S.W. Hawley, Rapra Technology Ltd.

Foams and Blowing Agents, J.M. Methven, Cellcom Technology Associates.

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Polymers and Structural Composites in Civil Engineering, L. Hollaway, University of Surrey.

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Injection Moulding of Rubber, M.A. Wheelans, Consultant.

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Adhesives for Structural and Engineering Applications, C. O’Reilly, Loctite (Ireland) Ltd.

Report 60

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Polymers in Marine Applications, C.F.Britton, Corrosion Monitoring Consultancy.

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Non-destructive Testing of Polymers, W.N. Reynolds, National NDT Centre, Harwell.

Report 61

Food Contact Polymeric Materials, J.A. Sidwell, Rapra Technology Ltd.

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Silicone Rubbers, B.R. Trego and H.W.Winnan, Dow Corning Ltd.

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Coextrusion, D. Djordjevic, Klöckner ER-WE-PA GmbH.

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Conductive Polymers II, R.H. Friend, University of Cambridge, Cavendish Laboratory.

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Designing with Plastics, P.R. Lewis, The Open University. Decorating and Coating of Plastics, P.J. Robinson, International Automotive Design.

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Fluoroelastomers - Properties and Applications, D. Cook and M. Lynn, 3M United Kingdom Plc and 3M Belgium SA.

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Polyamides, R.S. Williams and T. Daniels, T & N Technology Ltd. and BIP Chemicals Ltd.

Report 65

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Extrusion of Rubber, J.G.A. Lovegrove, Nova Petrochemicals Inc.

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Polymers in Household Electrical Goods, D.Alvey, Hotpoint Ltd.

Reinforced Thermoplastics - Composition, Processing and Applications, P.G. Kelleher, New Jersey Polymer Extension Center at Stevens Institute of Technology.

Report 67

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Developments in Additives to Meet Health and Environmental Concerns, M.J. Forrest, Rapra Technology Ltd.

Plastics in Thermal and Acoustic Building Insulation, V.L. Kefford, MRM Engineering Consultancy.

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Cure Assessment by Physical and Chemical Techniques, B.G. Willoughby, Rapra Technology Ltd.

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Toxicity of Plastics and Rubber in Fire, P.J. Fardell, Building Research Establishment, Fire Research Station.

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Acrylonitrile-Butadiene-Styrene Polymers, M.E. Adams, D.J. Buckley, R.E. Colborn, W.P. England and D.N. Schissel, General Electric Corporate Research and Development Center.

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Rotational Moulding, R.J. Crawford, The Queen’s University of Belfast.

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Advances in Injection Moulding, C.A. Maier, Econology Ltd.

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Compressive Behaviour of Composites, C. Soutis, Imperial College of Science, Technology and Medicine.

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Thermal Analysis of Polymers, M. P. Sepe, Dickten & Masch Manufacturing Co.

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Polymeric Seals and Sealing Technology, J.A. Hickman, St Clair (Polymers) Ltd.

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Rubber Compounding Ingredients - Need, Theory and Innovation, Part II: Processing, Bonding, Fire Retardants, C. Hepburn, University of Ulster.

Report 98

Advances in Biodegradable Polymers, G.F. Moore & S.M. Saunders, Rapra Technology Ltd.

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Recycling of Rubber, H.J. Manuel and W. Dierkes, Vredestein Rubber Recycling B.V.

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Reactive Processing of Polymers, M.W.R. Brown, P.D. Coates and A.F. Johnson, IRC in Polymer Science and Technology, University of Bradford.

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Speciality Rubbers, J.A. Brydson.

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Plastics and the Environment, I. Boustead, Boustead Consulting Ltd.

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Polymeric Precursors for Ceramic Materials, R.C.P. Cubbon.

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Advances in Tyre Mechanics, R.A. Ridha, M. Theves, Goodyear Technical Center.

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PVC - Compounds, Processing and Applications, J.Leadbitter, J.A. Day, J.L. Ryan, Hydro Polymers Ltd.

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Report 79

Rubber Compounding Ingredients - Need, Theory and Innovation, Part I: Vulcanising Systems, Antidegradants and Particulate Fillers for General Purpose Rubbers, C. Hepburn, University of Ulster.

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Anti-Corrosion Polymers: PEEK, PEKK and Other Polyaryls, G. Pritchard, Kingston University.

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Thermoplastic Elastomers - Properties and Applications, J.A. Brydson.

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Advances in Blow Moulding Process Optimization, Andres Garcia-Rejon,Industrial Materials Institute, National Research Council Canada.

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Molecular Weight Characterisation of Synthetic Polymers, S.R. Holding and E. Meehan, Rapra Technology Ltd. and Polymer Laboratories Ltd.

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Rheology and its Role in Plastics Processing, P. Prentice, The Nottingham Trent University.

Gas Assisted Moulding, T.C. Pearson, Gas Injection Ltd.

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Report 111

Polymer Product Failure, P.R. Lewis, The Open University.

Report 85

Ring Opening Polymerisation, N. Spassky, Université Pierre et Marie Curie.

Report 112 Polystyrene - Synthesis, Production and Applications, J.R. Wünsch, BASF AG.

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High Performance Engineering Plastics, D.J. Kemmish, Victrex Ltd.

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Rubber to Metal Bonding, B.G. Crowther, Rapra Technology Ltd.

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Plasticisers - Selection, Applications and Implications, A.S. Wilson.

Report 115 Metallocene-Catalysed Polymerisation, W. Kaminsky, University of Hamburg.

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Polymer Membranes - Materials, Structures and Separation Performance, T. deV. Naylor, The Smart Chemical Company.

Report 116 Compounding in Co-rotating Twin-Screw Extruders, Y. Wang, Tunghai University.

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Rubber Mixing, P.R. Wood.

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Recent Developments in Epoxy Resins, I. Hamerton, University of Surrey.

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Continuous Vulcanisation of Elastomer Profiles, A. Hill, Meteor Gummiwerke.

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Advances in Thermoforming, J.L. Throne, Sherwood Technologies Inc.

Report 120 Electronics Applications of Polymers II, M.T. Goosey, Shipley Ronal.

Volume 11 Report 121 Polyamides as Engineering Thermoplastic Materials, I.B. Page, BIP Ltd. Report 122 Flexible Packaging - Adhesives, Coatings and Processes, T.E. Rolando, H.B. Fuller Company. Report 123 Polymer Blends, L.A. Utracki, National Research Council Canada. Report 124 Sorting of Waste Plastics for Recycling, R.D. Pascoe, University of Exeter. Report 125 Structural Studies of Polymers by Solution NMR, H.N. Cheng, Hercules Incorporated. Report 126 Composites for Automotive Applications, C.D. Rudd, University of Nottingham. Report 127 Polymers in Medical Applications, B.J. Lambert and F.-W. Tang, Guidant Corp., and W.J. Rogers, Consultant. Report 128 Solid State NMR of Polymers, P.A. Mirau, Lucent Technologies. Report 129 Failure of Polymer Products Due to Photo-oxidation, D.C. Wright. Report 130 Failure of Polymer Products Due to Chemical Attack, D.C. Wright. Report 131 Failure of Polymer Products Due to Thermo-oxidation, D.C. Wright. Report 132 Stabilisers for Polyolefins, C. Kröhnke and F. Werner, Clariant Huningue SA.

Volume 12 Report 133 Advances in Automation for Plastics Injection Moulding, J. Mallon, Yushin Inc. Report 134 Infrared and Raman Spectroscopy of Polymers, J.L. Koenig, Case Western Reserve University. Report 135 Polymers in Sport and Leisure, R.P. Brown. Report 136 Radiation Curing, R.S. Davidson, DavRad Services. Report 137 Silicone Elastomers, P. Jerschow, Wacker-Chemie GmbH. Report 138 Health and Safety in the Rubber Industry, N. Chaiear, Khon Kaen University. Report 139 Rubber Analysis - Polymers, Compounds and Products, M.J. Forrest, Rapra Technology Ltd. Report 140 Tyre Compounding for Improved Performance, M.S. Evans, Kumho European Technical Centre. Report 141 Particulate Fillers for Polymers, Professor R.N. Rothon, Rothon Consultants and Manchester Metropolitan University. Report 142 Blowing Agents for Polyurethane Foams, S.N. Singh, Huntsman Polyurethanes. Report 143 Adhesion and Bonding to Polyolefins, D.M. Brewis and I. Mathieson, Institute of Surface Science & Technology, Loughborough University. Report 144 Rubber Curing Systems, R.N. Datta, Flexsys BV.

Volume 13 Report 145 Multi-Material Injection Moulding, V. Goodship and J.C. Love, The University of Warwick. Report 146 In-Mould Decoration of Plastics, J.C. Love and V. Goodship, The University of Warwick

Rubber Product Failure Roger P. Brown

ISBN 1-85957-330-4

Rubber Product Failure

Contents 1.

Introduction .............................................................................................................................................. 3

2.

Failure Analysis ........................................................................................................................................ 3

3.

The Reasons for Failure .......................................................................................................................... 5

4.

3.1

Design Error .................................................................................................................................... 5

3.2

Inappropriate Material .................................................................................................................... 5

3.3

Manufacturing Faults ...................................................................................................................... 6

3.4

Incorrect Installation ....................................................................................................................... 6

3.5

Unexpected Service Conditions ...................................................................................................... 6

3.6

Deliberate or Accidental Misuse ..................................................................................................... 7

3.7

Strategic Weakness ......................................................................................................................... 7

The Causes of Failure .............................................................................................................................. 7 4.1

General ............................................................................................................................................ 7

4.2

Temperature .................................................................................................................................... 8

4.3

Effect of Fluids ............................................................................................................................... 9

4.4

Weathering .....................................................................................................................................11

4.5

Ionising Radiation ......................................................................................................................... 12

4.6

Biological Attack .......................................................................................................................... 12

4.7

Fatigue ........................................................................................................................................... 13

4.8

Set, Stress Relaxation and Creep .................................................................................................. 14

4.9

Abrasion ........................................................................................................................................ 14

4.10 Electrical Stress ............................................................................................................................. 14 5.

6.

Preventing Failure ................................................................................................................................. 15 5.1

General .......................................................................................................................................... 15

5.2

Service Trials ................................................................................................................................ 15

5.3

Experience .................................................................................................................................... 16

5.4

Accelerated Testing ....................................................................................................................... 17

5.5

Quality Control ............................................................................................................................. 18

The Literature ........................................................................................................................................ 18 6.1

General .......................................................................................................................................... 18

6.2

Tyres .............................................................................................................................................. 19

6.3

Seals .............................................................................................................................................. 19

6.4

Other Products .............................................................................................................................. 20

1

Rubber Product Failure

7.

Conclusions ............................................................................................................................................. 20

Additional References ................................................................................................................................... 20 Abstracts from the Polymer Library Database .......................................................................................... 21 Subject Index ................................................................................................................................................. 95

The views and opinions expressed by authors in Rapra Review Reports do not necessarily reflect those of Rapra Technology Limited or the editor. The series is published on the basis that no responsibility or liability of any nature shall attach to Rapra Technology Limited arising out of or in connection with any utilisation in any form of any material contained therein.

2

Rubber Product Failure

1 Introduction It is only necessary to consider tyres to appreciate that rubber compounds are used in demanding applications. Over the last few decades the demand for improved performance and the increase in severity of service conditions over a wide range of rubber products has been addressed by the introduction of new materials, new compounding techniques and more sophisticated design methodology. Older people will well remember when both the tread life and the road holding capability of a typical tyre were greatly inferior to modern standards. Whilst innovative materials and techniques are generally well recorded in the literature there is still a reluctance to publish accounts of failures. This is not too surprising as the producers of products that have failed are usually none too keen to advertise the fact and those who diagnose the causes of failures are generally prevented from revealing their results by confidentiality agreements. A major contribution to making accounts of the failure of polymer products generally available has recently been made by Wright in a compendium of case histories covering both plastics and rubbers (9). There is also a review in this series that is mostly concerned with plastics but includes a few cases of rubber product failure (71). This review report will not attempt to systematically add to the detailed examples referred to above but will consider the process of failure diagnosis and the various causes of failures in service illustrated with reference to particular cases. Many of these examples of failures used for illustration are taken from unpublished investigations carried out by the author. The prime benefit of making accounts of failures public is the opportunity to learn from the mistakes and misfortunes of others. In contrast, the absence of accounts of failures will only make it more probable that others will repeat the same mistakes. When considering the published accounts of failures, it is clear that this has happened many times in practice as often the cause of failure has been diagnosed as due to a known problem or phenomena. It will be appreciated that what constitutes failure has to be defined. In the case of catastrophic failure, such as the rupture of an elastic band, this is obvious but in many cases there is no such clear end life. For example, is the end point when a few ozone cracks have appeared or when they have reached 5 mm in length? Broadly, the definition of end point is the level of a property at

which it is thought to be not a good idea to carry on using the product, which clearly could be some time before complete failure. Campion and Morgan (48) give a number of modes for failure definition from excessive abrasion (worn out) to formation of cracks/blisters in bulk due, for example, to explosive decompression. What is considered a reasonable lifetime spans a wide timescale. If a seal in a racing car engine lasts the race everyone is happy but in a normal road car ten years would be more reasonable. For products in the construction industry decades of service may be required. Short lifetimes in very low value products are accepted; some modern elastic bands are essentially one trip which defeats the misers who studiously reclaim and horde them. It will be appreciated that lifetime can be measured in time, number of cycles, mileage, etc. It is possible to dispute whether or not failure has occurred. In the inspection of rubber flooring the installer may believe it to be adequate whereas the purchaser considers there are excessive gaps, unevenness or debonding. Such instances are generally concerned with faults due to poor quality control rather than poor design or ageing. Whilst the vast bulk of rubber products give good service and satisfactory lifetimes, failures do occur. Failures are at the very least expensive due to the requirement to replace the parts, but generally the ill will generated will be a greater penalty. The situation is even more serious if the whole population of the product is threatened and sometimes the result is disaster. Clearly, it is sensible that every possible precaution is taken to prevent failures occurring and this should include study of past failures.

2 Failure Analysis If used for long enough, it can be expected that all products will eventually fail. A generalised model for failure rate is that initially there is a relatively high failure rate due to defective products followed by a plateau region of low failure rate (random failures) and finally an increasing high failure rate as the normal lifetime expires. This is not the most satisfactory of conditions, especially for safety critical products. Consequently, manufacturers seek to minimise the number of defective products and random failures through careful quality control and thorough testing at the design and prototypes stage to result in a very low

3

Rubber Product Failure

failure rate up to the design lifetime. In principle, the ideal of virtually no failures can be achieved by the combination of 100% inspection and testing together with replacement at intervals much less than the expected life. This is the policy applied to electricians’ gloves for high voltage working where, additionally, the user inspects the gloves before each occasion of use. Another example of deliberate replacement is critical seals in engines, whilst replacement of tyres is legally required in the UK when the tread depth reaches a particular level. Generally, if the service life matches expectations relatively little attention is paid to the failure although investigation could be valuable for future design and hence potentially valuable information is lost. When a product fails before its expected lifetime it is probable that questions will be asked as to why it failed. This information is required to know what steps to take to prevent it happening again or to know who to blame. The investigation of failed articles to deduce the causes of failure is variously termed failure analysis or failure diagnosis. The cause of failure may be at least superficially obvious - such as the abrading away of flooring or the gross swelling of a seal. The more detailed cause of the obvious failure is likely to be more important and also is likely to be more difficult to deduce. This relates to the two reasons for conducting a failure analysis future prevention and blame. In the latter case the investigation need only go as far as establishing fault and may not need to establish, for example, whether it was poor design or poor quality control - the manufacturer is at fault in either case. The main impetus for undertaking failure analysis should not be about blame but to find the root causes and learn from the mistakes. In a very recent inspection of an unsatisfactory floor installation, it would have been all too easy to blame the floor layer for gaps between tiles. However, it was primarily due to variation in tile dimensions and the occurrence of gaps would certainly continue to occur unless dimensional tolerances were tightened.

Inability to correctly diagnose the cause of failure can come from a shortcoming in any of these three factors. A considerable knowledge of material behaviour will not always suffice if a piece of evidence is overlooked or the sequence of reasoning has an illogical step. On the other hand, meticulous observation and reasoning will fall short of finding the correct answer without appropriate material knowledge. The analysis process can be defined in deceptively easy steps from the collecting of all the evidence and facts through examination and testing, to logical reasoning to find what possible causes can be eliminated, to arriving at conclusions. However, in many cases the process will be far from easy with plenty of opportunities for error. It is not appropriate here to consider the details of the failure analysis process but it needs to be recognised as an important discipline that requires experience and training. The following is a simplistic example of how the cause of failure can be unexpected. Examination of a hot water bottle showed that it had split with no signs of damage from external sources. The outside of the bottle gave the appearance of long use but it was claimed to be only a few weeks old. It was decided to test to the relevant British standard. The technician cut the bottle to obtain test pieces and noticed that the inside was in pristine condition. The technologist knows that bottles normally deteriorate by oxidation of the rubber accelerated by heat and perhaps trace metals in the water. The inside should fare worst. It transpired that the old lady who bought the bottle was filling it with cold water and heating it in her gas oven. Two ‘mistakes’ were made: nobody had the chance to interview the user at the outset and the technologist should have inspected the inside before deciding on tests. The plus side was a very observant test technician. It is also interesting to know that this failure was only diagnosed because the hot water bottle supplier had a policy at the time of replacing returned goods twice but on the third return commissioning a full investigation. The lady had previously cooked another two bottles.

There are three basic requirements for failure analysis: •

correct observation of evidence and gathering of facts

•

a logical sequence of measuring, reasoning and deduction

•

a knowledge of the material properties and behaviour.

4

Experts investigating a failure do not always agree. Experts for one side in a dispute over failed polyurethane bound rubber crumb playground surfaces were convinced it was due to the installer using too low a ratio of binder. Consideration of the resin supplier’s advice seemed to bear this out. However, the other side’s experts could not reconcile this with the installer having laid many other successful installations using nominally the same ratio. Closer

Rubber Product Failure

examination of the recommendations for resin showed that there was some confusion between percent by weight and percent by volume. When the density of the EPDM granules was taken into account the ratio used was lower than ideal but not unacceptable. Turning attention to the granules supplied then ascertained that there had been a change not notified to the purchaser, which resulted in greater absorption of resin and in consequence inadequate strength of the resin/rubber granule matrix. There were many lessons in this case and it indicates that the conclusion will perhaps depend on the avenue of investigation. All avenues need to be explored as there may be more than one contribution to the problem, for example: (1) However reputable a supplier and long standing his data sheets, they may still be misleading. (2) You cannot guarantee that a supplier will tell you of changes, particularly when he does not think that they are important. (3) It is not a good idea to run a process on the edge of its viability. (4) When there is no quality control testing of incoming materials trouble is likely sooner or later.

and strains. Increasingly, finite element analysis is used as an aid to design and in theory at least one would expect that it should reduce the incidence of design mistakes – although it is still dependent on the quality of input data. Design errors can also occur because the engineers involved do not properly appreciate the unique properties and behaviour of rubber which are so different from metals. It can of course be very difficult to predict the stress or strain levels in service for some products. Many years ago Rapra investigated brake hoses that had been successful on a number of cars but fatigue failures were experienced on a particular model. The details have been lost but the problem was associated with the particular geometry of the bending that the hose was subjected to. A different type of design error is where the product fails in a business sense because it infringes intellectual property rights or fails to comply with legislation. The author has investigated a number of cases where an artificial sports surface failed the performance specification because the shock pad was not designed with sufficient energy absorption. These installations were usable but not acceptable to the purchaser. In other cases of sports surfaces, design faults have resulted in dimensional instability some time after being put into use.

3.2 Inappropriate Material

3 The Reasons for Failure The basic reasons why products fail can be stated as: •

Design error

•

Inappropriate material

•

Manufacturing fault

•

Incorrect installation

•

Unexpected service conditions

•

Deliberate or accidental misuse.

3.1 Design Error Intrinsic faults in the design of a product generally imply a lack of appreciation of how the product is used in service, and what it is subjected to. This includes underestimating the stress or strain levels involved or not understanding the detailed distribution of stresses

Inappropriate choice of material arises for basically the same reasons as poor design but in many cases it could be argued that those responsible were in a position to know better. Probably more than for the other reasons for failure, wrong choice of material stems from overlooking known problems and the experience of others. Also, in many cases the problem with the material selected would have been realised if adequate testing had been carried out. There are certainly cases where rubber components are specified by the user for incorporation into a product but the user’s expertise in the material is questionable. Many years ago it amused staff at a rubber moulding company that a prestigious car manufacturer had black rubber written on the drawing as the material specification. Nevertheless he was always provided with the best quality.

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Rubber Product Failure

The author owned an outboard motor which was very well engineered except that the rubber sparking plug cover cracked in a matter of weeks. The company appeared unaware that there was more than one type of rubber nor that stress concentrations aided ozone cracking. A case involving the failure of numerous central heating radiator seals was basically caused by a material being recommended without proper understanding of the service conditions and the capability of the material. This may seem rather silly but, “How many times has a nonozone resistant rubber been used in an application where cracking was inevitable?” In the case of the radiator seals the misguided recommendation was compounded by lack of any proper evaluation of the new seals, which would have quickly found the problem. Failures can quite often be traced through a sequence of events. Here, the material manufacturer’s literature was not exactly helpful for the application in question, the moulder thought the material would be suitable on the basis of other applications, nobody did any tests and the radiator manufacturer did not conduct any trials.

manufacturing faults are in principle restricted to a more modest number. However, this number can be very significant and there is a rule that dictates it is likely to happen where the consequences are most serious. In an example of failed fuel hose the consequences were made worse by the faulty components being installed in ambulances.

3.4 Incorrect Installation A perfectly good product can be ruined or have its life curtailed by incorrect installation. If installation is by the manufacturer this is a form of quality control lapse whereas if installation is by the user or a third party it could be considered misuse. In failure analysis, wrong installation is often the first ‘defence’ from the supplier. One of the arguments advanced when a largely polymeric echo sounder unit was lost from the hull of a yacht (resulting in sinking of the vessel) was that it had not been attached properly. However, one would expect it to have pushed inwards not outwards due to water pressure.

3.3 Manufacturing Faults 3.5 Unexpected Service Conditions Manufacturing faults are taken to mean errors in the composition of the material, mistakes during processing and forming, and lapses in quality control. In one sense they are all attributable to quality control as the control procedures should detect compounding and processing mistakes. Thus there is a good chance of failure if quality control is lacking. Aeration diffuser membranes made of EPDM were found to have failed because of circumferential splits. The design of these diffusers includes perforations which result in the membranes being much stronger in one direction than in the other so the investigation involved testing mechanical properties in the two directions. The analysis was made easy because samples of new membranes were available and previously both new and used membranes had been tested for a different reason. It transpired that, although the used membranes had deteriorated to some extent, the most significant factor was that both the failed and unused membranes had much lower strength and elongation than the previously tested samples. It was not possible to exactly diagnose the reason for the change but it was clearly a control problem and most probably associated with degree of cure. Design and material selection errors are likely to affect the whole population of the product whereas

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Unexpected service conditions may be truly unfortunate in that despite careful research the unlikely still happened. In other instances the unexpected could have been expected if sufficient study of the application had been carried out. This problem is two sided in that the designer may be required to assess the needs of the application, but the user may fail to disclose vital information. Many instances of ozone cracking fall into the second category, but in one case involving cable glands on an oil rig the original arrangement was for them to be covered but this was changed at a later date. This case was also interesting as regards what constitutes failure - the cracks were really only a cosmetic problem, being away from the part of the gland doing the sealing. Fat contaminated the polyurethane floor at a margarine production factory causing it to break up. It is probable that the floor material manufacturer was not aware of the circumstances of use so that to him/her it would be unexpected service conditions, whereas considering the people who specified the floor it would be a case of incorrect choice of material. Yet again, it could be that the factory owner did not disclose the actual use of the floor area in question. Because the investigators were only required to prove damage from fat the actual human errors involved are not known.

Rubber Product Failure

3.6 Deliberate or Accidental Misuse Deliberate or accidental misuse is generally a fault on the part of the user – he or she is rather less likely to understand the material and its capabilities - but the supplier does need to make the limitations of the product known. The public has blind faith in tyres running under-inflated and probably a high percentage of tyre problems are self inflicted. With many products, failure due to accidental or deliberate damage is fairly obvious. However, expert examination is likely to be needed to establish whether a tyre failure was misuse or a manufacturing fault and diagnosis may be difficult. An investigation into leaking ethylene-propylene roofing membrane demonstrated no deficiencies in the material. Cuts and indentations were considered to have been caused by a sharp instrument and debris below the membrane respectively. It could also be established that the cuts were made before or during laying and hence not due to deliberate damage later. Hence, in this case what started as suspected deficient material moved to emphasis on misuse, but in actual fact was an installation problem.

3.7 Strategic Weakness With the possible exception of unexpected service conditions, the root causes can all be attributed to human error, even if in some cases the error was very difficult to foresee. When the reasons for failures are spelt out like this it all seems obvious but the fact is that, however obvious the steps to prevention may seem, failures happen. Wright (9) illustrates what he terms strategic weaknesses, which result in the wrong choice of material or in design errors. Polymer producers emphasise the good performance aspects of their materials and the product manufacturer only publicises successes. This may result in the poor properties of a material being overlooked and, through the lack of information, mistakes being made. Hence, it can be argued that a large proportion of failures are basically the result of lack of awareness, information that could have prevented the problem not being available or not heeded. When a lesson has been learnt after a failure it is also necessary to appreciate that the knowledge is valuable and has to be preserved to prevent the mistake being repeated by others at a later date. Wright gives an example which, although not involving rubbers, is illuminating. Casings for storing mines in readiness for war started to split. He quickly diagnosed

the problem as environmental stress cracking due to silicone grease used as a lubricant. Changing lubricant prevented the splitting. Ten years later he was called to investigate the same problem and found they had reverted to using silicone grease. All the staff had changed and the knowledge had been lost. It is not easy to apportion premature failures of rubbers to the basic reasons listed above, but it is highly probable that use of inappropriate materials outweighs all the others, followed by poor design and processing errors. Wright (9) considered some 5,000 failures of plastics products and found 45% due to material misselection and poor specification, 20% each due to poor design and poor processing and 15% due to abuse. He noted that the figures may underestimate failures due to abuse or accident as these are often obvious and do not invite high expenditure on independent investigation, whilst failure modes that threaten the whole population of a product may be overestimated. The proportions for rubber would be expected to be not dissimilar, although there are probably differences for particular products. Tyres are particularly exposed to misuse by the public and play and sports surfaces have probably had a high proportion of failures due to quality control.

4 The Causes of Failure 4.1 General Leaving aside abuse and gross faults that result in immediate failure, the cause of failure can be ascribed to one or more of a number of ‘degradation agents’ covering both environmental and mechanical factors as listed in Table 1. During its lifetime a rubber product will be exposed to one, or usually several, of these degradation agents. The contribution of each of them is often complicated to evaluate as they are generally interrelated, for example stress relaxation is accelerated by thermal degradation, and two agents may have a synergistic effect in that their effect, in combination, is greater or less than the sum of their individual effects. Whilst many properties will change because of the environment, they will change at different rates and hence to different degrees. For example, fatigue life often deteriorates more rapidly than tensile strength; with many synthetic rubbers hardness and modulus can rise appreciably whilst tensile strength remains virtually

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Rubber Product Failure

Table 1 Degradation agents (17) Agent

Type of ageing or effect

Temperature

Thermo-oxidation, additive migration, crosslinking, crosslink loss (reversion)

Light

Photo-oxidation

Ionising radiation

Radio-oxidation, crosslinking

Humidity

Hydrolysis

Fluids (gases, liquids, vapours)

Chemical degradation, swelling, additive extraction, cracking

Bio-organisms

Decomposition, mechanical attack

Mechanical stress

Fatigue, creep, stress relaxation, set, abrasion, adhesive failure

Electrical stress

Local rupture

the same; some fluids may cause little swelling but may extract protective agents or cause chemical attack. In many cases it will be possible to identify the critical or most important degradation agent(s) for the particular application, and material selection and design can be appropriately focused. As a simple example, there is not much point in compounding for maximum abrasion resistance if failure in practice will occur from cracking at low temperature.

rubber parts of a drug container into the drug, which is unacceptable, and could be considered another definition of failure. The presence of one plasticiser was a design error but the other was present as a result of contamination during processing.

Assessing the critical factors is not always easy and many instances of premature failure in service have occurred because a critical factor had been overlooked. Unfortunately, the longer a product is in service the greater the risk of the unusual or unanticipated occurring because over time there can be a change in operating conditions or the environment.

Low temperatures cause stiffening and eventually brittleness which in some applications can be the prime cause of failure, if the service temperature turns out to be lower than the glass transition temperature of the rubber used. For rubbers which crystallise at particular sub-ambient temperatures the long term effect of low temperature may also need to be considered. A slightly surprising case was found with soles of sandals made in a country where low temperatures did not occur but which cracked when used in frozen conditions.

Not surprisingly, experience of what most frequently causes failure of rubber products depends somewhat on the application. For products subjected to relatively moderate stresses and normal ambient temperatures, ozone cracking is very often the first problem whilst in applications involving elevated temperatures, the effect of thermal degradation on critical mechanical properties is generally the most common cause. In seals the combination of the effects of fluids and temperature on stress relaxation is most likely to be the important factor. In many of the cases of unexpected failure where apparently reasonable choices of material had been made the problem has been overlooking aspects of service exposure which potentially could occur. Typical of this is the acceleration of ageing through the presence of metal ions. Rubbers can indirectly be the cause of failure. Lewis (71) mentions a case of plasticisers migrating from the

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4.2 Temperature

Thermal expansion and contraction are reversible short term effects of temperature which may be very important in some applications. Repeated temperature cycling is essentially a form of fatigue. Large areas such as the shock pads of artificial sports surfaces can experience very considerable dimensional changes due to temperature. In one particularly baffling case artificial grass appeared to expand and formed waves when the temperature was lowered. The effect was found to be a result of internal stresses and the differential expansion between the grass and the rubber shock pad. Oxidative degradation is generally considered to be the most serious problem in the use of rubber at high

Rubber Product Failure

temperatures, but it also proceeds slowly at ambient temperature so that in the very long term it will be a factor for all products. Many of the failures which are thermal degradation related are due to an inappropriate rubber being used for the service conditions, particularly where there is a synergistic effect with other agents. An example of metal ion catalysis in central heating expansion joints is given later and copper in water supplies accounts for the early failure of many hot water bottles. Long term predictions from accelerated heat ageing tests are by no means easy but the problems are compounded if detailed knowledge of the service conditions is not available. The difference in performance may be quite marked for modest temperature change. A flexible hose failed through heat ageing and it was concluded that the nitrile/SBR blend used was only adequate for continuous service at about 70-80 °C whereas in practice 80 °C was reached. Less SBR in the blend would probably have resulted in satisfactory service. The Underwrites Laboratory (UL) index indicates the safe temperature of use of a material in air for up to 100,000 hours (11.4 years). Maximum continuous use temperatures for a range of rubbers with minimal stabilisation are shown in Table 2.

Table 2 Generic maximum continuous use temperatures for rubbers (9) Material Bromobutyl

Designation

MCUT (°C)

BIIR

120

Butadiene

60

Butyl

IIR

100

Butyl (resin cured)

IIR

130

Chlorinated PE

CPE

120

Chlorobutyl

CIIR

120

Chloroprene

CR

90

CSM

120

Chlorosulphonyl Ebonite

80

Epichlorohydrin

CO

130

EPDM (sulphur cured)

EPDM

120

EPDM (resin cured)

EPDM

150

Ethylene vinyl acetate

EVM

110

Ethyl acetate

ACM

150

Fluoroelastomer

FPM

210

FVMQ

200

Fluorosilicone Isoprene

IR

60

The effect of ageing on reducing fatigue resistance or increasing the degree of stress relaxation may be rather more important than the changes produced in such basic properties as tensile strength, elongation at break and modulus. This illustrates that it is the critical factor in service that needs to be evaluated and basic information in suppliers data sheets could be misleading.

Natural rubber

NR

60

Nitrile (< 20% ACN)

NBR

110

Nitrile (> 20% ACN)

NBR

120

Nitrile/PVC polyblend

PNBR

90

Nitrile (carboxylated)

XNBR

110

Nitrile (hydrogenated)

HNBR

150

Because oxygen is used up in the ageing process it follows that the rate of degradation is dependent on the rate of oxygen supply. This means that the thicker the product the greater the differential between the ageing of the surface and the interior and this is another complication to predicting lifetime. Massive bridge bearings have given good service for decades but a thin membrane of the same material may only last a few years or even months.

Perfluoroelastomer

FFKM

260

Styrene-butadiene

SBR

70

Urethane (ester)

AU

75

Urethane (ether)

EU

75

4.3 Effect of Fluids It should be noted that, in environmental exposure tests, the changes in properties are normally monitored at ambient temperature even when accelerated heat ageing tests have been used. Temperature has a short term effect on properties and where the service temperature is elevated the properties should be monitored at that temperature.

Fluids encompass a whole range of chemicals, both liquids and gases which can come into contact with rubber in various ways during service. Fluids can be absorbed and cause swelling of the rubber, or may extract soluble constituents of the compound, or may catalyse oxidation or have direct chemical effects.

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Rubber Product Failure

Figure 1 Time-swelling curves for three different materials in contact with test fluid (17)

Tests in which rubbers are exposed to liquids are often called swelling tests simply because the resulting change in volume of the test pieces is by far the most commonly used measure of the effect of the liquid. The term oil ageing is also sometimes used because standard grades of mineral oil are the liquids most often specified. Figure 1 illustrates three different types of material behaviour in contact with a test liquid. Volume change is a very good measure of the general resistance of a rubber to a liquid. A high degree of swelling clearly indicates that the material is not suitable for use in that environment, although in certain applications, such as seals, a negative swelling (extraction) could be equally bad as regards service. Absorption of fluid is a reversible process and consideration has to be given as to whether in service fluid contact will be intermittent.

If chemical reactions take place, including the effect of temperature, the degradation will continue long after equilibrium absorption has been reached and volume change alone will not be a sufficient measure of the effect of the fluid. There are numerous instances where failure was the result of a rubber being used that was not sufficiently resistant to liquids encountered, in some cases because contact with the liquid in question had not been expected. A particular form of this problem is when the service liquid becomes contaminated, one case being where water stops swelled because oil leaked in during flooding. Buried products, such as cable, may be exposed to soil contaminants. In one case a ducted cable (see Figure 2) disintegrated due to the effects of exposure to solvents

Figure 2 Schematic of waveconal cable (9)

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Rubber Product Failure

from a car respraying plant above it. The PVC sheath swelled and cracked exposing the devulcanised rubber underneath to similar attack (9). The permeation of water into rubber is very slow compared to organic liquids and even thin products require a very long time to reach equilibrium. As an illustration, it has been found that the effect of water absorption on compression stress relaxation at ambient temperature is not noticed until upwards of one year. Apart from being absorbed and having a plasticising effect, moisture can produce hydrolysis in some materials, such as polyurethanes. Further, it can have a synergistic effect with other agents, such as UV light. The number of applications where gases (other than air and ozone) are involved is relatively small compared to liquids, but an extra consideration where high pressures are involved is the possibility of explosive decompression due to absorbed gas rupturing the rubber when pressure is released. This was found to be the cause of blisters in sleeves of gas line valves at one particular installation. There had been many successful installations but problems only occurred at particular conditions of temperature and pressure and was hence difficult to foresee. Nevertheless, the underlying cause was thought to be associated with poor dispersion of ingredients and the relatively low strength of the material which could have been investigated earlier. Although ozone exists in only very small quantities in the atmosphere, it is important because less than 1 pphm (part per hundred million) can severely attack nonresistant rubbers in the strained condition. Indeed, ozone attack can be the major factor as regards lifetime when exposed to the atmosphere. The effect of ozone is to produce clearly visible and mechanically very damaging cracking of the rubber surface. It only attacks rubber in the strained condition, although with the less resistant rubbers the ‘threshold strain’ for attack may be very low. Rubbers with unsaturated (C=C) bonds in the main chain have very poor ozone resistance. Time after time complaints, and, less often, serious problems, arise because of ozone cracking due to an insufficiently resistant rubber being selected. The relative ozone resistance of a variety of rubbers in the unstabilised state is shown in Table 3. It appears that often the likelihood of cracking is overlooked for such reasons as the degree of strain being underestimated or simply through lack of knowledge. One factor is that the relation of severity of cracking to strain is not simple. By definition there are no cracks below the threshold strain for any given exposure period. A few cracks, often large, are found at strains slightly above

Table 3 Relative ozone resistance of unstabilised rubbers (17) Rubbers with very poor resistance

Diene rubbers (e.g., natural rubber, styrene butadiene rubber, nitrile rubber, budadiene rubber)

Rubbers having some resistance

Butyl rubber, hydrins, hydrogenated nitrile rubber, polythioethers, polychloroprene

Rubbers having good resistance

Acrylics, chlorosulphonated polyethylene, ethylenepropylene rubbers, fluorocarbon rubbers, silicone rubbers

the threshold and the cracks will become more numerous and smaller at progressively higher strains. It is quite possible for the cracks at very high strains to be so small as to be invisible to the naked eye, although after longer times they will coalesce.

4.4 Weathering Weathering is taken to mean exposure to the atmosphere which includes sunlight, temperature, precipitation, ozone and any pollutants present. However, particularly when accelerated testing is considered the emphasis is on the effect of UV light. Both the intensity and the spectral distribution of sunlight vary with the location, time of year, the atmospheric conditions and the angle of the sun. Consequently, the apparent resistance of a material will vary considerably depending on the installation and even service trials could easily be misleading. It also makes predicting weathering performance from accelerated tests very difficult, particularly as there is uncertainty in the match of the spectrum of the lamp used to that of the sun. Acceleration factors are calculated but they are approximate to say the very least. However, as an example the author estimated acceleration factors of 4.7 and 11 for a xenon lamp with respect to exposure in Arizona and London. It also implies that a material would last over twice as long in London as in Arizona but that factor would doubtless change when the temperature difference was also considered. The effect of light on rubbers has generally been considered to be much less important than it is for plastics. With any degradation being restricted to the surface layer it is thought only of consequence for thin

11

Rubber Product Failure

walled articles and coated fabrics, plus coloured materials (the effect on pigments may be much greater than on the rubber polymer). This is probably a complacent view as back in 1970 Angert and Dubok (a.1) reported significant weathering effects on both black and white filled compounds. Recent experience at Rapra is that artificial weathering in fluorescent tube apparatus at 45 °C produces quite large changes in many compounds. Clearly, this will include a contribution due to temperature and an attempt was made to isolate the purely weathering effect. This was achieved using the results of accelerated ageing tests and applying a WilliamsLandel-Ferry (WLF) shift, so that inevitably the uncertainties were very large. In many cases the observed changes on weathering could be accounted for by the effect of temperature, but in at least as many cases there was evidence that the effect of weathering was significant and, also, that in other cases the effects of weathering and temperature were in opposite directions. Despite the uncertainty, the evidence was sufficient to suggest that the effects of weathering should not be ignored. Nevertheless, failures in rubbers attributed to UV light do not seem to be numerous. The only cases seen by the author involved chalking and colour change and as one of the factors in the cracking of roofing membranes. Even if the effect of UV light itself is not generally serious, the temperature reached by light exposure in outdoor exposure can be surprisingly high and cause much greater effect. In sunlight, with an ambient temperature of 26 °C a black rubber is likely to reach 50 °C and a white one 33 °C. With an insulated backing this could rise to as high as 80 °C for a black material and under glass temperatures can exceed 100 °C. Hence the lifetimes could be expected to be very different depending on the aspect of the product. This is seen in the earlier failure of seals on the south side of buildings.

Alpha radiation has the least penetrating power and its effects are limited to the surface layers of a material so it only needs to be considered when a surface is contaminated by an alpha emitter. Beta radiation has a range of up to a centimetre or two whilst X-ray, gamma radiation and neutrons are very penetrating. Gamma radiation is commonly used in sterilisation of medical devices. The relative resistance of a range of rubbers is shown in Table 4.

Table 4 Gamma radiation resistance of a range of rubbers (17) Rubber type

Insignificant damage (radiation dose, Gy)

Butyl rubber

Up to 10,000

Acrylic rubber

Up to 100,000

Silicone rubber

Up to 100,000

Chlorosulphonated rubber

Up to 100,000

Nitrile rubber

Up to 100,000

Fluorocarbon rubber

Up to 100,000

Polychloroprene rubber

Up to 100,000

Styrene-butadiene rubber

Up to 500,000

Ethylene-propylene rubber

Up to 500,000

Polyurethane rubber

Up to 500,000

Where radiation is a consideration it needs to be appreciated that the effects can depend on dose rate. Also it should be noted that temperature can have a significant effect on the degradation as it controls both the rate of oxygen diffusion into the material and the rates of reaction of the products of the irradiation.

4.6 Biological Attack 4.5 Ionising Radiation Ionising radiation means atomic and nuclear particles, i.e., gamma rays, electrons neutrons, etc. The intensity of ionising radiation at the earth’s surface is not high enough to significantly affect rubbers and hence radiation exposure is only a consideration in connection with applications in nuclear plant and possibly where radiation is used to induce crosslinking or for sterilisation. Each of the types of radiation has a characteristic way of interacting with matter and transferring its energy.

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Biological attack in service is relatively rare, although rubbers and/or additives can prove attractive to living organisms. Attack by animals or insects is only likely to be a serious problem in tropical countries where there have been reports of such things as bus window seals being eaten. In Europe there has been considerable concern that products such as rubber pipe seals are susceptible to microbiological degradation. Although actual cases of damage appear to be few, the cost implications in underground pipe networks are considerable and research has identified the

Rubber Product Failure

polymers and compounds that should be avoided. Another important area is in medical implants.

For rubber products it is possible to distinguish between two types of fatigue situation:

The other side to the coin of attack by living organisms, particularly microorganisms, is when it is welcomed. Increasingly, biodegradable polymers have been introduced which are specially formulated so that they are broken down by microorganisms relatively quickly and hence their disposal after use causes no environmental problems.

(1) Where the repeated cyclic deformation cause heating of the rubber by the stressing process – heat build up.

4.7 Fatigue There are of course occasions when a rubber product fails mechanically in an abrupt manner after little or no service that could be said to have induced such failure. Such failures must be associated with either gross under design in terms of mechanical strength, a serious manufacturing error, use with stresses in excess of those expected or deliberate or accidental damage. An example of the last situation was a fire hose which burst during use injuring a fireman. The failure analysis concluded that the hose had been cut, most likely by being dragged over a piece of glass. In another case the stopper of a hot water bottle together with its threaded ferrule came out of the bottle causing scalding of the user. There was no bonding of the ferrule to the neck of the bottle nor was there a mechanical arrangement to prevent its removal and this was either a design error or manufacturing fault. A few years back there were a spate of early failures of rubber playgrounds which were mostly a result of poor installation practice or lack of quality control of the rubber granules used. Sports and play surfaces are a little unusual in that they are often ‘manufactured’ in situ. Hence, there is no chance of quality control testing on the final product and rejecting non-complying product before it reaches the user. More usually, mechanical failure occurs after a period of service as a result of environmental degradation or fatigue. Fatigue is taken here to mean the application of repeated cyclic deformation which results in a change in stiffness, a loss of mechanical strength and ultimately rupture. The mechanisms which may contribute to breakdown include thermal degradation, oxidation and attack by ozone as well as the propagation of cracks by tearing. The manner of degradation will vary according to the geometry used, the type of stressing and the environmental conditions.

(2) Where cracks are induced and/or propagated without significant heating – flex cracking or cut growth. The first type generally occurs with bulky objects, such as in tyres. The second type is by far the most common and occurs with any product which is repeatedly stressed, including tyres. In the heat build up situation, as well as the temperature rise there will be a change in stiffness and ultimately the temperature can be so high that rupture of the product occurs. It is not difficult to measure or compute the temperature likely to be reached through dynamic stressing and design to avoid excessive heating, but for longer periods of use the associated ageing has to be considered. Excessive heat build up is particularly likely to occur at flaws in the product and this was found to be a problem in tank pads at the boundaries of multiple blanks used to load the mould. Cracks grow in nominally perfect mouldings from minute flaws although any induced damage such as a cut will be a potential failure site. The rate of growth is, as would be expected, dependent on strain. In many practical situations the flexing that a product is subjected to is quite complex and it is important that localised strains due to stress concentrations are considered at the design stage. As well as the maximum strain, the minimum strain experienced on each cycle is very important as cycles passing through zero strain are particularly severe. The traditional fatigue tests which operate in a bending mode generally suffer from poor definition of maximum, and particularly minimum, strain. Tests in tensile mode with interpretation using fracture mechanics principles are more satisfactory. For such products as hose and belting, product tests are devised that seek to simulate the service movements. With regards to the strains in service it is important to distinguish situations where the applied deformation is strain or stress amplitude controlled as clearly materials of different stiffness will not behave the same. This has been found to be the simple answer to why one material lasted longer than another in a particular dynamic application.

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Rubber Product Failure

Fatigue is often the cause of failure in bonded joints. Although it is relatively easy to detect a bad joint by using simple quasi static tests, such tests are not so good at distinguishing between quite good and excellent bonds. The less than excellent bond may be prone to failure through repeated stressing.

4.8 Set, Stress Relaxation and Creep For seals and gaskets the most critical parameter is generally the ability to maintain a seal. In most cases it is the ability to maintain the sealing force (stress relaxation) rather than the ability to recover dimensions (set) which is important. Set is more frequently use to characterise materials because it is easier to measure, but the relation between the two is not always simple. The great majority of failures in seals is due to loss of sealing force and/or excessive set rather than the loss of mechanical strength. Even in temperate conditions when the effect of ageing may be small considerable set or stress relaxation will occur through physical processes. This was well illustrated by the Rapra long term ageing programme where thermal ageing was relatively small for many materials even after 40 years exposure but well before that time set of some materials was approaching 100% (67). Nevertheless, the environmental conditions, particularly temperature and the presence of fluids, greatly influence the degree of stress relaxation or set and, hence, the useful life, and frequently the problems stem from the use of a material which is inadequate for the service conditions over the desired lifetime. Wright (9) cites a case of a flexible hose carrying hot water where set under the end fittings resulted in failure and the diagnosis was that the polymer used was not suitable for the temperatures encountered whereas it worked well with cold water. With careful selection of material and attention to design rubber seals can be made to perform for long times under very severe conditions of temperature and in the presence of oils in such products as motor engines, but the wrong choice can result in catastrophic failure. Creep is also related to set and stress relaxation but the number of applications in which it is an important factor is relatively few. Notable exceptions are antivibration mountings and bearings and generally the success of the component is very dependent on the design used.

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4.9 Abrasion Abrasion is clearly only an important factor in the failure of particular products but then it can be the limit to useful life, as for example in shoe soles and rubber flooring. The mechanisms by which wear of rubber occurs when it is in moving contact with another material are complex but the principle factors involved are cutting and fatigue. It is possible to categorise wear mechanisms in various ways and commonly distinction is made between abrasive wear, fatigue wear and adhesive wear. Additionally, wear by roll formation is sometimes considered as a separate mechanism. There can also be corrosive wear due to direct chemical attack on the surface and the term erosive wear is sometimes used for the action of particles in a liquid stream. In any particular wear situation more than one mechanism is usually involved but one may predominate. Abrasive wear requires hard, sharp cutting edges and high friction. Fatigue abrasion occurs with rough but blunt surfaces and does not need high friction. Adhesion wear is much less common but can occur on smooth surfaces. The mechanism, and hence the rate of wear, can change, perhaps quite suddenly, with the conditions such as contact pressure, speed and temperature. In any practical circumstance the mechanisms may be complex and critically dependent on the conditions. Consequently, the critical factor as regards estimating service life by laboratory tests is that the test conditions must essentially reproduce the service conditions if a good correlation is to be obtained. Even a comparison between two rubbers may be invalid if the dominant mechanism is different in test and service. The range of conditions and the complexity encountered means that this is very difficult or impossible to achieve. A great deal of research has been carried out for such very important applications as tyres and conveyor belts and there is a wealth of experience. It seems that unexpected premature failures are mostly related to misuse.

4.10 Electrical Stress Clearly, electrical stress is only of concern in electrical applications of rubbers and generally restricted to incidences of high voltage or current. Relatively short term premature failures due to breakdown will be due to flaws in the product, assuming that the material has been adequately evaluated. Hence, it is common for

Rubber Product Failure

critical products such as electricians’ gloves to be 100% proof tested. In the longer term a particular area of concern is partial discharges occurring within or at the surface of insulation. If there are local flaws or voids, the local electrical stress can exceed the breakdown level of the material at that point. With an AC voltage, partial discharges occur at each half cycle and the ‘electrical fatigue’ causes degradation of the insulation and a conducting path. Water treeing arises with polyethylene insulated cables in wet conditions and at modest voltages where water diffuses into the insulation and, under particular conditions, forms fine channels. Wright (9) notes that this has also been seen in EPDM rubbers and he also cites a case of automotive cooling hose where a voltage was apparently generated by electrochemical processes between the coolant and metals in contact with the coolant. This makes a good example of a case where the most unexpected occurred. Apart from the direct electrical stress, heating due to the current or dielectric heating will result in thermal ageing. Thermal or UV ageing will promote tracking and may reduce breakdown strength.

5 Preventing Failure 5.1 General It follows from most premature failures being attributable to human error, that most such failures could be prevented by appropriate action at the design, material selection and production stages. Leaving aside lapses in quality control, this means selecting materials and a design that are satisfactory for the service conditions, which in turn implies that an analysis needs to be carried out to make predictions of the long term performance of the product. There are undoubtedly intrinsic problems in reliably predicting service lifetime of rubbers due to the uncertainty of, and variation in, the service conditions and the timescales for which products are expected to perform. However, the three basic approaches to assessing service life are: •

Real (or simulated) service trials

•

The use of experience

•

Accelerated testing

5.2 Service Trials Few would argue against real service trials being the first choice, although in practice the conditions and timescale required frequently rule it out completely. Simulated service trials using test rigs are more widely feasible and are often considered essential for critical components. Product tests are generally devised to suit a particular product and application and the range of sophistication is very wide. It can be very difficult to devise a satisfactory test rig that adequately reproduces the conditions of service and as they get more complicated so the cost escalates. For this reason, rigs are often designed to cover one aspect of service, for example the mechanical stressing expected, with environmental effects evaluated separately. Product test rigs commonly operate with a degree of acceleration, for example by increasing frequency in a fatigue test, which means that the problems of extrapolation inherent in accelerated testing apply. Although a great number and diversity of product test rigs have been used, the cost and difficulties have restricted their application and it is fairly clear from accounts of failures that there are many instances where a service trial or rig test could have detected the problem before it occurred in the field. For example, in the case of radiator seals cited earlier the use of a relatively basic test rig would have found the deficiencies in the material chosen. A different use of service trials is in the procedure of simulated design life. The product is subjected to environmental exposures which equate, with the inevitable approximations, to a chosen design life and then performance is assessed by operating the product. The exposures normally have to involve accelerated procedures and may comprise several environmental agents applied simultaneously or sequentially. The process can be illustrated by a very simplistic example. It can be claimed that from accelerated ageing and via the Arrhenius relation reaction rates for mechanical properties of a rubber are known at least approximately. From this, the product could be given a simulated lifetime of, say, 10 years by heat ageing and then actually operated under service conditions. Using a tyre as an example, it might be found that although the mechanical properties after a simulated 10 years were reasonable they deteriorated very rapidly in heavy service because the additives used to protect against high running temperatures had been depleted. Hence one would be advised not to use tyres stored for long periods even if they seemed intact.

15

Rubber Product Failure

5.3 Experience

This was seen in practice with tyres on Green Goddess fire engines kept for emergencies by the Home Office in the UK, which were put into store for many years and then put into service in an emergency. The tyres looked fine but failures occurred because over the long storage time the antioxidants were depleted and degradation was then rapid at running temperatures. Under tyre testing small ozone surface cracks grew quite rapidly, which allowed oxygen and moisture to reach the viscose rayon cords, which rapidly broke down. Figure 3 shows the effects of 3,000 miles of testing on surface cracking.

It is probable that the majority of rubber products are designed largely on the basis of experience. A great many product specifications do not include real performance tests but are based on general material properties using tests which do not yield fundamental results. Products made to such specifications are satisfactory in practice, essentially because experience over many years has shown that materials meeting the minimum requirements work, not because any scientifically based predictions have been made. When

(a)

(b)

Figure 3 Surface cracking of stored tyres before (a) and after (b) 3,000 miles at 40 mph on a test drum (9)

16

Rubber Product Failure

significantly different materials are introduced, new products are envisaged or the conditions of service change there are several sources of experience which can be usefully tapped: •

Using data generated by others.

•

General knowledge of materials.

•

Knowledge of the same material in other applications.

•

Knowledge of how other materials performed in similar applications.

•

Predicting from known performance to different conditions.

•

From comparison of new material with one proven.

In cases discussed by Wright (9), time and again it is seen that knowledge was available that could have prevented the failure but it was ignored or simply was not available to the people concerned. Expansion joints for a central heating system made from a natural rubber/polychloroprene blend severely degraded due to metal ions catalysing thermooxidation. It is well known that many rubbers are susceptible to this type of degradation and it is a distinct possibility that a water supply will contain metal oxides. The material had been chosen on the basis of cost and resistance to water at 85 °C and there had been no direct contact between the supplier and end customer. Polyurethane oil seals failed due to hydrolytic degradation which happened because over time the oil became contaminated with water. All polyurethanes are prone to hydrolysis and oil absorbs water during use. If testing had been done in used oil the problem would have been obvious. Eventually the material was changed to EPDM. Nitrile/PVC coated fabric diaphragms used in a fuel lift pump suffered ozone cracking, those from one supplier being much more badly affected than those from a second supplier. It transpired that neither compound contained an antiozonant and ozone attack had not been considered a critical factor even though one side of the diaphragm was exposed to air and subject to tensile strain. The reason why one compound cracked more badly was due to it being softer and hence it was subjected to larger strains. In these examples it is not unreasonable to suggest that the inadequacy of the selected material for the service

conditions should have been avoided. However, it has to be recognised that in some cases service conditions can be quite unexpected. As an extreme example, the use of an EPDM replacement hose in the fuel line of a pleasure cruiser which resulted in the boat bursting into flames could hardly be blamed on the (unknown) manufacturer of the hose.

5.4 Accelerated Testing Accelerated testing can be seen as the least attractive option because of the inherent cost and difficulties of making reliable predictions. Nevertheless, in a great many circumstances accelerated tests have to be relied on at least in part. Regardless of how you go about making assessments, service conditions are not constant and, with long expected lifetimes, either the degree of extrapolation is very large or even accelerated tests need considerable timescales. In addition, there are uncertainties associated with knowing the critical degradation agents and the critical properties for the application. The problems particular to accelerated tests are related to the extrapolation process. It is essential that extrapolation rules from the test conditions to those of service are known and have been verified such that they can be used with confidence. In practice this is only an ideal as extrapolation procedures have not generally been comprehensively validated and almost certainly will not give accurate predictions in all cases. The only choice is to use the best techniques available and apply them with caution. An account of available prediction techniques is included in the Practical Guide to the Assessment of the Useful Life of Rubbers (17). In general there are two stages to modelling the degradation process: (1) Obtaining a function for the change of the parameter(s) of interest with time. (2) Obtaining a function for the rate of change of the parameter(s) with the level of the degrading agent. Using these relationships the change in property on exposure to longer times and lower levels of the degrading agent can be predicted. Clearly, the success of the process is critically dependent on the validity of the models used but, as mentioned above, extrapolation models have not generally been comprehensively validated.

17

Rubber Product Failure

By far the best known model is the Arrhenius relation which relates temperature and reaction rate through:

knowledge of the performance of the material was relied on, whereas accelerated tests to cover the actual service conditions would have warned of the likelihood of failure.

ln K (T ) = − E / RT + C Where: K(T) is the reaction rate for the process E is the reaction energy R is the gas constant T is absolute temperature C is a constant. A plot of ln K(T) against 1/T should yield a straight line with slope E/R. A general approach is to apply the time-temperature superposition principle in which plots of the parameter against time are shifted along the time axis to construct a master curve and the WLF equation used to perform the superposition: Log ( aT ) =

a(T − T0 ) b + (T − T0 )

where, aT is the shift factor of an isotherm determined at temperature T, in relation to the isotherm at the reference temperature T0, and a and b are two adjustable coefficients dependent upon the material. By definition when T=T0, log(aT) = 0 and there is no shift to apply. Any relation between degradation, acceleration and time is only likely to be valid for a limited range of acceleration because the degradation mechanism may change with the level of the agent. The best results will be obtained with the lowest acceleration levels but at the cost of longer test times. Where multiple degradation agents apply, the extrapolation rules for each have to be combined in such a way that synergistic actions are accounted for. Such procedures are likely to be very complicated and add greatly to the uncertainty. Regardless of the validity of the extrapolation procedure, the intrinsic experimental uncertainty of the measurements will be magnified as the degree of extrapolation increases so that predictions will always be very far from precise. In practice comprehensive accelerated test programmes are often of limited scope or omitted altogether largely because of the cost. This was probably the case for examples of failure due to thermal ageing where general

18

5.5 Quality Control It is self evident that mistakes in manufacture could result in premature failure of the product and consequently quality control in some form is essential. Unfortunately, case histories show that sensible control precautions are not always applied and in some instances appear to be totally absent. There are examples of inadequate control at all stages from checking of incoming materials, through lack of testing of the product to incorrect installation. As one illustration of quality control lapses causing failure, nitrile/PVC hoses analysed by the author failed from ozone cracking. Although suitably formulated, there had been a processing error and because the quality assurance (QA) testing for ozone resistance had not been carried out this went undetected. For this case, there was in theory a control procedure which is one stage better than no provisions for control, although the result was the same. One way in which break down of quality control occurs is through misunderstanding of who is controlling a material, the supplier or the purchaser. In this and other aspects of quality control it would be hoped that the very widespread adoption of accreditation to ISO 9000 standards will have lead to a general improvement in the rubber industry.

6 The Literature 6.1 General As said earlier, the literature is lacking in direct accounts of specific failures. Almost all of the instances mentioned that came from the author’s experience have not been published simply because they were examined in commercial circumstances. However, there are many papers giving examples of measuring the degradation of rubber materials in particular environments. As well as giving results for changes caused by the degradation agents (often accelerated), in many cases they provide information on how performance can be improved by selection of alternative materials. Despite it being generally thought that data suitable for reliably predicting service life is scarce, this has received many times more attention than analysis of causes of failure.

Rubber Product Failure

There are also many papers considering methodology for prediction of lifetime from accelerated tests (for example (50, 61, 62) and this has been considered comprehensively in a guide to lifetime prediction (17). Stevenson (54) refers to costly mistakes having been made in critical offshore applications, from which the appropriate lessons have not always been learned, and considers some of the applications and the material evaluation requirements. A less common use of accelerated tests is to estimate remaining lifetime. Heat ageing of two compounds and applying the time temperature superposition principle and models based on Miner’s rule of cumulative material damage is described by Gillen and Celina (41). However, Sun and co-workers (50) found that Miner’s rule did not apply for fatigue of black filled NR and SBR. Increasingly, computer modelling, or virtual testing, is being developed to aid design of rubber components to provide satisfactory service lifetime. Some studies are briefly outlined by Chouchaoui (47, 79) where problems of unsatisfactory products were solved by modelling, which include the crimping of a hose, several seals, a diaphragm, damping mountings, a railway crossing pad and a valve. The failure of rubber components subject to dynamic conditions is frequently due to the development of cracks and is generally termed fatigue. Several recent papers consider the process of crack development and the estimation of fatigue life. Zhoa and Ghebremeskel (37) review the effects of polymer macro and micro structure on the failure mechanisms of butadiene and styrene-butadiene in considerable detail. Hawkes and co-workers (161), for example, consider the tearing energy approach whilst Mars (46) introduces the concept of cracking energy density to aid prediction of fatigue. Yeoh (118) demonstrates how finite element analysis can be applied to compute tearing energy for classical test pieces. The literature on failures has been very significantly added to, in fact probably doubled, by the case histories given by Wright (9) and from which some examples have been extracted. Apart from the case studies, this book is also useful for the accounts of degradation mechanisms that are included.

6.2 Tyres Because of their importance from a safety angle, failure of tyres receives considerable attention. In an overview

of possible causes of tyre failure Vance (32) highlights the interest taken by the US authorities in any cases of death or injury which may be related to tyre performance and the resultant recall of tyres and court proceedings. Interestingly, the tyre related incidences of fatality are miniscule compared with the total number of road related incidents. Tyres are unusual in that they are used by the public in a great variety of service conditions and are likely to be subjected to abuse rather more than most rubber components in typical engineering applications. Consequently, it could be argued that it is surprising that catastrophic failures are not more common and indicates that generally the level of technology and quality control is high. The problem of accumulated structural damage resulting from running tyres under- or overinflated is considered by Wagner (34). The conclusion of a report into abnormal tread separation of particular brands of tyres (39) was that various factors contributed, including design, manufacturing factors and external factors such as underinflation. Months later experts were disagreeing (12 extra) as to whether failures were largely due to design defects or to incorrect operating conditions. Another report (72) cited increased speeds and poor maintenance for an increase in the failure rate of lorry tyres. A Chinese paper (105) apparently claims that premature failure is mainly a result of underinflation.

6.3 Seals Seals are perhaps one of the most severe applications of rubber, often being subjected to harsh environments in terms of temperature and chemicals and being required to not only maintain mechanical integrity but to also retain their sealing force. The essential property of stress relaxation (change in sealing force) needs to be measured under conditions that equate with service and measurement continued or extrapolations made for long times, which is often difficult to achieve. Pannikottu and co-workers (45) describe a finite element method for modelling stress decay which is said to be consistent with experimental results. The analysis of seal failure modes is discussed by Page (63) who classifies causes of failure as structural response (such factors as seal and housing design), environmental response and human intervention (including poor manufacture and fitting and the inadequate dissemination of knowledge). Modification of the standard compression set test is suggested to give better correlation with stress relaxation. A review has been given (66) of the Parker O-ring handbook which is a manual detailing O-ring design.

19

Rubber Product Failure

Probably the most famous of seal failures ever was the Challenger disaster which has been described in some detail by Lewis (71). This resulted from the effect of overnight low temperature on Viton elastomer. Perhaps most shocking is that this was a case where there had been several warnings of potential failure.

There have been a number of Japanese papers on fatigue failure of rubber products but translations have not been found in most cases other than a wide ranging review (100) and a study on failure of timing belts (156).

6.4 Other Products

7 Conclusions

Failure of condoms would clearly be of concern and a survey (165) appears to reveal a significant number of failures. Other workers (25) have characterised defects in condoms and investigated artificial defects. The failure of silicone rubber in breast implants has received plenty of coverage in the popular press and several technical articles have been reviewed by Lewis (71). It appears that there have been a number of failure mechanisms but they all generally relate to lack of thorough testing to cover the expected lifetime and all service conditions. For cases of failed tissue expanders he suggests the causes were a combination of poor design and poor manufacturing. Lewis also cites investigations of problems with synthetic heart valves and implanted pacemaker leads, including mechanical inadequacy, cure variations and biodegradation. Such medical products are subject to apparently exhaustive testing but despite the precautions taken failures have still occurred. Problems with leaking under-bonnet hoses have been investigated but only brief details were published (80). Lewis (71) mentions the case of ozone cracking of fuel lines on Fiat cars which resulted in fires.

It is essentially self evident that the study of failures is essential to successful design and the prevention of reoccurrence. It follows that it is important that accounts of failures are published so that the experience is of value to others. The practice is that relatively little has been published although there are indications that this situation is improving. Many of the case studies of failures demonstrate the frequency with which the failure could have been prevented if existing knowledge had been available to or had been heeded by the people concerned. This unavailability or disregard of knowledge is not restricted to small companies and even very prestigious establishments could be called guilty. Deficiencies in design, material selection and control may have far reaching implications. In some cases a seemingly small lapse has been disastrous or at least very expensive.

Summaries of papers presented at a RILEM symposium on the durability of building sealants have been published (129), which include case studies on the inspection of failed joint systems.

In contrast to the number of reports of failure case studies, there are many papers on the measurement of degradation in various environments. Although the process of predicting lifetime is undoubtedly difficult and testing is expensive, it is essential that performance is fully evaluated at the design stage and quality routinely maintained by testing. It appears that too often these essential steps are omitted or inadequately carried out.

Stress analysis of failures in the form of cracks in cord rubber composites as a result of fatigue has been carried out which is said to be of help in estimating the severity of local failures (35).

Generally, it must be concluded that in too many cases service trials were deemed not feasible, sufficient knowledge or experience was not available and accelerated testing was thought too expensive.

A detailed investigation was made into the failure of rigid polyurethane foams of different densities that had been deliberately formed with elongation of the cells in the longitudinal direction (36). It was found that the failure mode changed with change of density but in a different manner to that found previously for materials foamed in the vertical direction.

Additional References

20

a.1

L.G. Angert and N.N. Dubok, Soviet Rubber Technology, 1970, 11, November, 29.

References and Abstracts

Abstracts from the Polymer Library Database Item 1 Gummi Fasern Kunststoffe 54, No.12, Dec. 2001, p.816-26 German SEALS AND JOINTS IN FUEL CIRCUITS - HOW TO MINIMIZE EMISSIONS Streit G P; Achenbach M Parker Hannifin GmbH Ways of reducing the emission of volatile organic compounds from the fuel systems of passenger cars and trucks are discussed. Rubber hoses and seals, particularly those with quick connectors and the fuel rail, are all responsible for the emission of VOCs due to permeation and/or leakage. The need for a special elastomer compound which gives low emission rates over the whole temperature application range is emphasised, in addition to requirements for a new, patented geometry which helps to fulfil future requirements as regulated by the various government bodies. Permeability data are presented for grades of Viton, HNBR, and FVMQ. 31 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.846497 Item 2 Polymer Testing 21, No.2, 2002, p.187-93 ENHANCED RESISTANCE OF POLYURETHANE SEALANTS AGAINST COHESIVE FAILURE UNDER PROLONGED COMBINATION OF WATER AND HEAT Chew M Y L; Zhou X Singapore, National University Cohesive failure was shown to arise for currently-used commercial PU sealants under extreme conditions of combined water and heat. A formulation was developed for a two-component PU sealant which was resistant to cohesive failure under prolonged exposure to combined water and heat. The newly-developed sealant exhibited retention of TS, hardness and elastic recovery after prolonged 70C water immersion. A test package was designed for evaluation of cohesion under these conditions. 12 refs. SINGAPORE

Accession no.845972 Item 3 160th ACS Rubber Division Meeting - Fall 2001. Cleveland, Oh., 16th-18th October 2001, Paper 86, pp.33, 012 EXPLOSIVE DECOMPRESSION DAMAGE IN ELASTOMERIC FLEXIBLE CONNECTIONS Kumar A; Hogan M E; Riggs D C

© Copyright 2002 Rapra Technology Limited

AK Consulting Engineers; Oil States Industries Inc. (ACS, Rubber Div.) The behaviour of elastomeric flexible connections (FlexJoint) in offshore pipelines transporting hydrocarbon fluid/gas mixture under high pressure (10-25 MPa) and temp. (100C) was studied by means of small-scale testing corroborated by non-linear finite element analysis. Under sustained high pressure and temp., rubber layers absorbed hydrocarbon gases. When the internal pressure was rapidly decreased (due to shutdown or other emergencies), the explosive expansion of the absorbed gases within the elastomer caused internal rupture of the elastomer structure (also known as explosive decompression damage(EDD) that could gradually affect the load-bearing capacity of the connection. A new test method was developed to identify the principal design variables that affected the extent and nature of EDD. Small-scale specimens representing full-scale connections were designed with the aid of non-linear finite element analyses. The specimens were tested in a specially designed pressure vessel representing the extreme environment and exposure that were encountered in offshore oil production. The results showed that EDD could adversely affect the performance of an elastomeric connection. Under similar environmental and loading conditions, thicker rubber layers were more susceptible to EDD. With adequate confinement of rubber, the effects of EDD could be reduced to acceptable levels. 10 refs. USA

Accession no.843010 Item 4 160th ACS Rubber Division Meeting - Fall 2001. Cleveland, Oh., 16th-18th October 2001, Paper 21, pp.13, 012 COMPOUND VISCOELASTIC PROPERTIES AND FRACTURE MECHANICAL BEHAVIOUR IN TRUCK TIRE DURABILITY PREDICTION Moneypenny H G; Mowdood S K; Nahmias M Moneypenny Tire & Rubber Consultants; Pirelli Tire LLC; Pirelli Settore Pneumatici (ACS, Rubber Div.) Truck tyre durability is discussed with reference to the importance of identifying the mode, initiation point, propagation and cause of failure. The process is illustrated for two possible types of failure mode, i.e. tread separation and breaker/ply ending separation. In the development of new compounds, it is important to consider the operating conditions (strain/stress/temp. levels) of the component in the running tyre. The use of compound fracture mechanical behaviour measurements in the development of sidewall compound with improved cut initiation/propagation resistance is described. The retreadability of the truck tyres is also considered with

21

References and Abstracts

reference to the stability of the various tyre components to mechanical excitation, heat and oxidative ageing. 5 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; NETHERLANDS; USA; WESTERN EUROPE

Accession no.842959 Item 5 Gummibereifung 76, No.10, 2000, p.58-9 German TYRE TESTING SYSTEMS Mutz K-H As the market leader, the specialist tyre testing firm SDS Systemstechnik GmbH makes tyre defects visible through opto-electronics. Methods of testing new and remoulded tyres are described. A new ‘Interferometric Tire Tester System’ is discussed, including measurement of belting, inner liners, pressure distortion and broken fibres. Also examined are efficiency and savings on staff costs as well as examples of defects that have been detected. SDS SYSTEMTECHNIK GMBH EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

ASSESSMENT OF THE LEVEL OF SERVICE PROPERTIES OF TYRES PRODUCED BY THE CIS AND PROBLEMS OF THEIR IMPROVEMENT Putankin K S; Kalinkovskii NIIShP The level of service characteristics of tyres was assessed by the analysis of data on the life of over 50, 000 tyres used and recorded in the Moscow region in the period from 1995 to 1999, the results of laboratory road testing of tyres, results of bench tests of different manufacturers, and the study of the design and materials of tyres by different tyre works in the CIS and the leading foreign companies. The tyres were assessed from criteria of international priority requirements: safety (grip properties, stability and controllability, speed properties, reliability, aquaplaning speed), comfort (external noise, nonuniformity, stability at high speeds), and economy (service life, coefficient of rolling resistance, repairability, and mass). Results are discussed. (Article translated from Kauchuk i Rezina, No.2, 2001, pp.18-20). CIS; COMMONWEALTH OF INDEPENDENT STATES

Accession no.838102

Accession no.838562 Item 6 Structural Adhesives in Engineering VI. Conference Proceedings. Bristol, 4th-6th July 2001, p.211-4, 012 AERODYNAMIC HEATING OF ROCKET MOTOR ADHESIVE BONDS Wylie P D; Hobman C E; Tod D A DERA (IOM Communications Ltd.) The effect of temp. and stress on the bond strength between insulating liner (Hypalon chlorosulphonated PE) and solid rocket propellant (hydroxy-terminated polybutadiene) was studied. Initial failure stresses at temps. ranging from 20 to 160C at 20C intervals were determined and samples were then loaded to a percentage of the determined failure strength at each temp. and their time to failure was recorded. The results obtained showed that there was a significant reduction in the strength of the propellant and the strength of the propellant-liner interface at high temps., particularly over 100C. Evidence was also found to suggest that some thermal degradation of the test samples occurred during constant load testing. Apart from the temp., the time under load was critical in predicting the suitability for service of these bonds. 1 ref. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.838228 Item 7 International Polymer Science and Technology 28, No.12, 2001, p.T/15-7

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Item 8 Shawbury, Rapra Technology Ltd., 2001, pp.148. 30 cms. Rapra Review Rept. Vol.12, No.7, 2001; NALOAN RUBBER ANALYSIS - POLYMERS, COMPOUNDS AND PRODUCTS Forrest M J Rapra Technology Ltd. Edited by: Ward S (Rapra Technology Ltd.) Rapra.Review Rept. No.139 A number of elemental, spectroscopic, chromatographic and thermal techniques are described for the analysis of rubber compounds and products. This review aims to provide an introduction to the techniques and methods that are used to carry out quality control work on rubbers, to investigate the failure of rubber products and to deformulate rubber compounds. 379 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.838077 Item 9 Shawbury, Rapra Technology Ltd., 2001, pp.xii, 400, 26cm, 9 FAILURE OF PLASTIC AND RUBBER PRODUCTS - CAUSES, EFFECTS AND ACES STUDIES INVOLVING DEGRADATION WRIGHT D Rapra Technology Ltd. This book describes mechanisms of polymer degradation for the following reasons: Thermo-oxidation; Photo-

© Copyright 2002 Rapra Technology Limited

References and Abstracts

oxidation; Degradation due to ionising radiation; Chemical attack; Environmental stress cracking; Other miscellaneous effects, including treeing, electrochemical degradation and biodegradation. Each failure mechanism is illustrated with a number of case studies, many of which are based on Dr. Wright’s own experiences whilst working at Rapra. In each case he describes the circumstances of the failure, and discusses both the consequences of the failure and the lessons that may be learned from it. Each chapter is well referenced. UK, DEPARTMENT OF TRADE & INDUSTRY EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.837010 Item 10 Materials World 9, No.5, May 2001, p.14-5 TYRE-D OUT? Hill S CSIRO and Monash University have developed a simple technique for nondestructively testing the internal condition of the material in rubber components in service. The technique is based on NMR technology. It is claimed the technique will give earlier warning if a rubber part such as a conveyor belt is degrading or losing elasticity, so that the part can be replaced well before failure occurs. It should be equally suitable to other rubber products such as vehicle tyres. CSIRO AUSTRALIA

Accession no.834605 Item 11 Gummibereifung 77, No.8, Aug.2001, p.78-9 CONCORDE IS TO TAKE OFF AGAIN Mutz K Engineers at Michelin have recently developed a new aircraft technology using a high-modulus reinforcement material developed by the company in 1999. The new tyre technology is called “Near Zero Growth” or NZG, and offers high damage-resistance - a key quality in the field of aviation. This article reports on damage tests carried out in Spain an NZG radial tyre and a bias tyre, where the former produced excellent results, meeting all the specifications in regard to damage resistance. The Concorde is shortly to be equipped with these new tyres. MICHELIN; EADS; CEAT EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; SPAIN; WESTERN EUROPE; WORLD

Accession no.833850 Item 12 Tire Technology International Annual Review, 2001, p.158-62

© Copyright 2002 Rapra Technology Limited

IMPACT SIMULATIONS IN THE LAB Bolden G C; Smith J M; Flood T R Standards Testing Laboratories Inc. A report is presented on STL’s road hazard impact testing machine for tyre/wheel assemblies, which was developed using SAE J1981, as a starting point. STL’s testing protocols and data quantification are described and its applicability to forensic tyre analysis for revealing and validating failure modes is discussed. Some cautions with regard to significant changes in parameters, which may give rise to different results and conclusions to those obtained using a specific range of parameters, are noted. SAE USA

Accession no.833109 Item 13 Rubber and Plastics News 31, No.4, 17th Sept.2001, p.6 ASSOCIATIONS GIVE INPUT ON TIRE MONITOR PROPOSAL Stumpf T This article explains the US National Highway Traffic Safety Administration’s proposed regulations mandating tyre pressure monitoring systems in new passenger vehicles by model-year 2004. It also presents the comments and suggestions in response to the proposals from three major US tyre-related associations: the Rubber Manufacturers Association, the Tire Association of North America, and the International Tire & Rubber Association. RUBBER MANUFACTURERS’ ASSN.; NORTH AMERICA, TIRE ASSOCIATION; INTERNATIONAL TIRE & RUBBER ASSOCIATION; US, NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION; FORD MOTOR CO.; FIRESTONE USA

Accession no.832638 Item 14 International Polymer Science and Technology 28, No.9, 2001, p.T/20-2 PERFORMANCE OF BUS TYRES Gudkov V A; Tarnovskii V N; Ganzin S V Volgograd, State Technical University A statistical analysis is made of the service life of bus tyres and the economy of various tyres under different bus service conditions, including urban, suburban and intercity routes, with reference to tyres produced at the Bobruisk, Belotserkovsk, and Nizhenkamsk works, prior to withdrawal from service. Factors affecting the service life of tyres mean that tyres fail at different stages of their life. An analysis of the causes of failure indicate that 7090% of tyres fail due to treadwear. 3 refs. (Article translated from Kauchuk i Rezina, No.1, 2001, p.21). RUSSIA

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References and Abstracts

Item 15 Industria della Gomma 44, No.10, Dec.2000, p.16-22 Italian GUIDE TO THE SOLUTION OF RUBBER-TOMETAL BONDING PROBLEMS Peters D Par Chemie Consideration is given to the different steps involved in rubber-to-metal bonding, including surface preparation of metal substrates, the application of primers and adhesives, and moulding, vulcanisation, curing and posttreatment processes. Factors which can lead to weak adhesion and bond failure are discussed, and approaches to the identification and correction of such problems are outlined. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.828666 Item 16 Rubber to Metal Bonding. Proceedings of a one-day seminar held Shawbury, 30th January 1997.. Shawbury, 1997, paper 5, pp. 5. 012 PROBLEM SOLVING IN RUBBER TO METAL BONDING Worthington K Compounding Ingredients Ltd. (Rapra Technology Ltd.) Typical applications are examined in which rubber to metal bonding failures are possible, and possible solutions are examined. Examples of problem solving include glycol resistance in a hydromount test, and fuel resistance of a turbo injection inlet manifold gasket. Retreading a tyre with a PU precured tread is examined, with reference to the selection of a suitable bonding agent. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.827807 Item 17 Shawbury, Rapra Technology Ltd., 2001, pp.vi, 156, 25cm, 93 PRACTICAL GUIDE TO THE ASSESSMENT OF THE USEFUL LIFE OF RUBBERS Brown R P This book provides practical guidance on assessing the useful service life of elastomers. It covers test procedures and extrapolation techniques together with the inherent limitations and problems. The information can be applied to help maximise the effectiveness of a durability testing programme. The results of a project studying 40 years of natural rubber ageing and an accelerated testing programme conducted by Rapra have been drawn on to indicate the limiting factors for particular materials and methods. The book is split into three parts. The main

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headings in Part One - Basics are: Introduction; The problems; The choice of approaches; Degradation agents; Degradation mechanisms; Time dependent limitations; Critical factors; Parameters to monitor degradation; Preparation of test pieces. The main headings in Part Two - Product Tests and Experience are: Simulating service; Experience; Principles of product testing. The main headings for Part Three - Accelerated Tests are: Fundamental problems; Designing an accelerated test programme; Effect of temperature; Effect of liquids; Effect of gasses; Weathering; Fatigue; Abrasion; Other degradation agents; Service conditions; Prediction techniques; Limitations and pitfalls in accelerated testing. (35 refs.) RAPRA TECHNOLOGY LTD. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.826524 Item 18 IRC 2001. Proceedings of a conference held Birmingham, 12th.-14th. June. Birmingham, IOM Communications, 2001, p.596-607. 012 NON-LINEAR FINITE ELEMENT ANALYSIS OF FABRIC REINFORCED DIAPHRAGMS Daley J R; Ellaway T M; Mays S TISPP UK Ltd.; Dowty Engineered Seals (Institute of Materials) Fabric reinforced elastomer diaphragms are critical components in valves, pressure regulators, actuators, pressure switches, expansion chambers and pumps used in a variety of end-use industries. They need to be able to withstand operating environments with extreme pressures and service temperatures, and in order to design reliable diaphragms, realistic prediction techniques are required to enable better models of seal behaviour and failure. One such technique, Non-Linear Finite Element Analysis (NLFEA) is examined in this paper. An example of modelling a fabric reinforced diaphragm is demonstrated through the use of beam elements in combination with solid elements. The material properties and weave of the fabric are shown to be critical in the prediction of the failure mode and the behaviour of the diaphragm during the stroke cycle. The paper concludes that FEA can help limit the stress diaphragms are exposed to, predict potential wear areas and reduce prototype costs. 4 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.820090 Item 19 IRC 2001. Proceedings of a conference held Birmingham, 12th.-14th. June. Birmingham, IOM Communications, 2001, p.334-346. 012 USE OF ELASTOMERS FOR AUTOMOTIVE

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References and Abstracts

FUEL AND AIR CONDITIONING FLUID CONTAINMENT Harrison C; Campion R P (Institute of Materials) The use of elastomers as seals, hoses and diaphragms in automotive air conditioning and fuel operating systems is examined, and the environmental concerns relating to emissions which has made fluid loss prevention increasingly important. In addition, in recent years, the use of higher pressures for both types of system has also added to the difficulties of containment. Fluid loss can be due to permeation through the elastomer (e.g. through seals or hose walls), or through flaws, and/or can be by leakage past the seal. An example where the latter becomes most important is with modern snap-fit or barb connectors, especially in dynamic situations. This paper enlarges upon these matters, describes equipment and procedures developed for making relevant measurements, and provides data. Details are also given of equipment capable of operating at realistically high pressures both for permeation measurements and for seal leakage testing under vibrating conditions appropriate to automotive service. Test data obtained include permeation rates and related coefficients, and numbers of cycles to leakage onset for several automotive service-realistic elastomer/ fluid (gas or liquid) combinations. Rationales are outlined. Some extreme forms of elastomer service failure modes, such as explosive decompression fracturing, or extrusion of the seal into the adjacent housing, are briefly mentioned. 8 refs. MATERIALS ENGINEERING RESEARCH LABORATORY LTD. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.820066 Item 20 Tire Business 18, No.22, 12th Feb.2001, p.1/18 TREAD ACT COULD AFFECT, ELIMINATE SOME TIRE LINES Fisher P J Fleet Tire Consulting US legislation, the TREAD Act, which was passed in October 2000 after the Firestone tyre recall, establishes early-earning reporting requirements of safety-related tyre and automotive defects, and criminal penalties for falsifying or withholding information on vehicle safetyrelated defects. This article examines in detail the impact this new legislation will have on businesses in the US, products sold, and how the law could even affect a company’s survival. FIRESTONE; US, RUBBER MFRS.’ASSN.; US, NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION USA

Accession no.818276

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Item 21 Rubber Chemistry and Technology 74, No.1, March/April 2001, p.79-88 AGEING OF NATURAL RUBBER IN AIR AND SEAWATER Mott P H; Roland C M US, Naval Research Laboratory Accelerated ageing experiments are carried out on an NR vulcanisate exposed to air and to seawater. Failure strain, shown to correlate well with the fatigue lifetime, is used to monitor the extent of degradation. The effect of temperature on the rate of ageing follows an Arrhenius law, with activation energies equal to 90 + or -4 and 63 + or -3 kJ/mol for air and seawater ageing, respectively. The difference can be accounted for by the difference in oxygen concentration for the two environments. 35 refs. USA

Accession no.818146 Item 22 Rubber Asia 15, No.3, May/June 2001, p.81-2 RESISTANCE TO AIR PERMEATION - WATER LEAKAGE Bader H F Akron Rubber Development Laboratory Inc. A manufacturer of natural latex sports ball bladders seeks an improvement in air permeation. As an alternative to total replacement of the NR latex, it is suggested that an over dip is applied of another latex polymer at a thickness which does not adversely affect the bounce. Information concerning water leakage testing of examination gloves and condoms is presented. A toy balloon maker seeks a solution to losses due to tears when removing the balloon from the dip form. Whether the low temperatures encountered in unheated cargo planes can affect nitrile gloves is considered. USA

Accession no.816968 Item 23 Shawbury, Rapra Technology Ltd., 1997, pp.96. 30 cms., 1/6/01. Rapra Review Rept. Vol. 8, No. 12, 1997. NALOAN POLYMERIC SEALS AND SEALING TECHNOLOGY Hickman J A St.Clair (Polymers) Ltd. Edited by: Dolbey R (Rapra Technology Ltd.) Rapra.Review Rept. No. 96 This review of polymeric seals and sealing technology covers the types of seals available and the elastomer materials used for their manufacture. The properties of specific materials chosen for seal design are outlined, and minimum and maximum usage temperatures are

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References and Abstracts

indicated. Applications of these seals in heat exchangers, EMI/RFI shielding, explosive decompression, suspension units, and in high-power mechanical hammers are described. The failure of seals is discussed, and a case history is included to illustrate the failure of a seal, and its subsequent redesign. Seal materials examined include NR, EPM, EPDM, IIR, CR, NBR, ECO, HNBR, ACM, AEM, silicone rubber, fluorosilicone rubber, fluorocarbon rubbers, polysulphide rubber, polyurethane rubber, and PTFE. 400 refs. Photocopies and loans of this document are not available from Rapra. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.815494 Item 24 Tire Business 18, No.23, 26th Feb.2001, p.1/20 BFS RECALLS 98, 500 FIREHAWKS Moore M

showed that this test method did not increase the size of pre-existing microscopic defects. Examination also showed that these creation techniques generated reproducible defects within a condom type, with the size of acupuncture needle defects varying less than laser-drilled defects. Results of water leak testing showed that the leakage characteristics of defects were affected by the material type, the condom shape and size, the type of defect and the defect size, and the presence of lubricant. 9 refs. USA

Accession no.813791 Item 26 Nippon Gomu Kyokaishi 73, No.10, 2000, p.555-61 Japanese EXAMPLES OF TROUBLES WITH ACRYLIC RUBBER AND COUNTERMEASURES Kubota I

For the second time in six months, Bridgestone/Firestone is recalling tyres. The company will voluntarily recall approximately 98, 500 Firestone Firehawk GTA-02 tyres, size P205/55R16 for what is described as a ‘design issue’. Some 88, 000 of the tyres were fitted as original equipment on 22, 000 Nissan Altima SE sports models, while the rest went to the replacement market. The bulk of the vehicles and tyres were sold in the USA. The tyres featured an extra-wide steel belt which left insufficient distance between the steel belt edge and the tread surface, leaving potential for a crack to develop at the bottom of the circumferential shoulder groove, and progress to the edge of the steel belt. No accidents, injuries, lawsuits or defect claims are involved. The DOT identification numbers of the tyres subject to recall are listed. BRIDGESTONE/FIRESTONE INC.; NISSAN

Information is presented on mixing of acrylic rubbers, with details on tackiness, content of other materials, carbon black dispersion and dispersion of other fillers, and processing and vulcanisation of acrylic rubbers. 6 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.813618

USA

A discussion is presented of the structure of NBR type rubbers and their basic properties and processing, the nonrubber components present, ways of avoiding processing problems, and some examples of defects in commercially available NBR. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.813617

Accession no.815354 Item 25 Journal of Testing & Evaluation 29, No.2, March 2001, p.214-9 CHARACTERIZATION AND CREATION OF DEFECTS IN CONDOMS Kerr L N; Chaput M P; Boyd S M; Galevi E A; Millward P A US, Food & Drug Administration Defects in condoms were examined, characterised and compared with defects introduced using various techniques. Eighty-five percent of the condom defects examined were classified as either a hole (void in material) or a slit (puncture). Laser drilling and puncturing with a 160 micrometre diameter acupuncture needle artificially introduced similar types of defects. Microscopic examination of the created defects, before and after FDA water leak testing,

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Item 27 Nippon Gomu Kyokaishi 73, No.10, 2000, p.548-54 Japanese TROUBLE-SHOOTING OF NBR AND HNBR Komatsu K

Item 28 Nippon Gomu Kyokaishi 73, No.10, 2000, p.541-7 Japanese TROUBLE-SHOOTING OF FLUOROELASTOMERS Nagasawa A Examples are given of problems arising during processing of fluororubbers, e.g. roll tackiness during milling, impurities on the roll, curing faults, splitting during demoulding. Articles from this journal can be requested

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References and Abstracts

for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.813616 Item 29 Nippon Gomu Kyokaishi 73, No.10, 2000, p.533-40 Japanese EXAMPLES OF FABRICATION TROUBLES OF SILICONE RUBBER AND COUNTERMEASURES Sumimura S A discussion is presented of troubles that can occur with the properties (permeability, heat resistance, contact obstacles and impurities, foreign bodies) and processing of silicone rubber. 6 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.813615

Crusader Chemical Co. A general overview is presented of possible causes of tyre failure in its various forms. Following the Bridgestone/ Firestone recall of 4.8 million tyres, the US Senate has passed the Transportation Recall Enhancement and Documentation Act (TREAD Act). Induced by the massive recall of BFS tyres, this legislation requires car, tyre and parts manufacturers to make changes to ensure public safety. New cars will include dashboard low pressure warning systems for tyres. Tyre manufacturers will be bound by a reporting system to establish an early warning reporting system to assist the NHTSA in identifying safety-related defects, to update passenger car tyre testing standards, and to develop a dynamic roll-over test, enaction of regulations to assist consumers in identifying tyres subject to a recall and to notify the NHTSA of any foreign government safety tyre recalls on a motor vehicle or its parts. The effect of the TREAD Act on the tyre industry is considered. USA

Item 30 Nippon Gomu Kyokaishi 73, No.10, 2000, p.524-32 Japanese TROUBLE-SHOOTING OF RUBBER PRODUCTS Ohtake Y Trouble shooting in the case of products made from fluororubbers, polyurethane rubbers, hydrogenated nitrile rubber and silicone rubbers is explained. 2 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.813614 Item 31 International Polymer Science and Technology 28, No.2, 2001, p.T/43-53 ELASTOMER-GAS SYSTEMS Zuev Y S NIIEMI Open Joint Stock Co. Factors determining the solubility, diffusion and permeability of gases in elastomers, and the influence of high temperatures and pressures on these processes are examined, together with a study of the possibility of increasing the working life of seals under these conditions. 46 refs. (Translated from Kauchuk i Rezina, No.4, 2000, p.36) RUSSIA

Accession no.811261 Item 32 Rubber Asia 15, No.2, March/April 2001, p.23-4 WHAT CAUSES TYRE FAILURES? Vance P

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Accession no.811222 Item 33 Pigment & Resin Technology 30, No.2, 2001, p.109-13 ANALYSIS OF BLEACHING PROCESSES IN ALUMINIUM PIGMENTED CHLORINATED RUBBER COATINGS UNDER OSMOTIC EFFECT Cayuela F; Morcillo M Basque Country, University; CSIC Aluminium pigmented chlorinated rubber coatings, widely used for steel ship protection, can be bleached when exposed to total immersion conditions. A deep study on the development of the decolouration processes of these coatings, applied on rolled steel specimens exposed to total immersion conditions in aqueous solutions with different salinity, is carried out. The relationship between external salinity and contamination by sodium chloride of the steel/coating interface in the bleaching processes is analysed. The influence of the osmotic processes in the coating bleaching is also established. Periodic visual inspections of the coating films, together with a deep analysis of the coating microstructure, by means of optical microscopy and scanning electron microscopy provided with microsonde analysis, are used. The bleaching processes of the coatings mainly depend on the salinity of the external solution, while the influence of the steel/ coating interface contamination is not relevant. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.811148 Item 34 Modern Tire Dealer 81, No.11, Nov.2000, p.16-7

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References and Abstracts

MTD ANSWERS THE BURNING QUESTION: WHY DO SOME RADIAL TYRE TREADS PEEL? Wagner E Tire Technical Services Inc. In the absence of faulty tyre production, which is quite rare, the problem of tread peels may lie in “accumulated tyre structure damage”. Running tyres overloaded, at sustained high speeds or underinflated can and do contribute to a structural breakdown within the internal confines of the tyre body. For example, a tyre operated significantly underinflated for a specific load can result in the weakening of bonding material strength due to excessive heat generation and resultant deterioration of constituent materials. Another instance of accumulated tyre structure damage can occur when a radial truck tyre, for example, strikes a rock or curb with sufficient speed and force to severely impact the shoulder area where steel belts and body ply meet. USA

Accession no.810120 Item 35 Polymers & Polymer Composites 9, No.1, 2001, p.15-24 STRESS ANALYSIS OF FAILURES IN CORDRUBBER COMPOSITES Pidaparti R M V; May A W Purdue University Stress analysis of failures in the form of cracks due to fatigue of cord-rubber composites was carried out using micromechanical 2D and 3D finite element analysis. The von Mises-Tresca stresses were computed from the results of finite element analysis and compared. Results show that crack type, loading and crack size have a strong effect on the values of the von Mises-Tresca stress. Use of the results of the von Mises-Tresca stress should help in estimating the severity of local failures in cord-rubber composites, it is proposed. 12 refs. USA

Accession no.808305 Item 36 International Journal of Damage Mechanics 10, No.1, Jan.2001, p.3-42 FAILURE MODES OF FOAMS: INFLUENCE OF ORIENTATION OF VOIDS Theocaris P S; Sokolis D P Athens, National Academy An experimental investigation was undertaken to assess the failure behaviour of a series of PU foams of variable specific density. All the foam materials examined were transversely isotropic materials, whose axis of symmetry was, however, the weak axis of the medium. Simple uniaxial tension and compression tests were executed and the experimental data were introduced into the elliptic

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paraboloid failure surface criterion. This condition was used for the comparison of the failure loci, associated with primary failure, of the PU foams of different porosities. The results obtained indicated that the dependence of the failure modes of a mixed foam upon the specific densities of its strong and weak-axis elements, as well as upon their relative proportions, was expressed in terms of a smooth transformation of its failure behaviour from the ordinary C-strong one to the irregular T-strong one. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE; WESTERN EUROPE

Accession no.807150 Item 37 Rubber and Plastics News 30, No.9, 27th Nov.2000, p.14/21 REVIEWING FRACTURE AND FATIGUE FACTORS Zhoa J; Ghebremeskel G Ameripol Synpol Corp. It is explained that most rubber products due to the development of cracks, as a result of being subjected to environmental factors. This paper reviews in depth the underlying failure mechanisms, and discusses ways and means of minimising them. It presents the effects of polymer molecular weight, the styrene content of SBR, and the diene microstructure on fracture and fatigue life of the vulcanisates. It also discusses the role played by carbon black and vulcanising systems on fracture and fatigue. 56 refs. MONSANTO USA

Accession no.804735 Item 38 Your Ticket to Outstanding Color and Additives. RETEC 2000. Conference proceedings. Washington, D.C., 17th-19th Sept.2000, paper 12 DURABILITY? Coleman E CP Technology Inc. (SPE) The concept of durability is discussed with reference to rubber and plastic products. The level of durability achieved depends on a complex interaction of ingredients, formulation, fabrication, and assembly, and the environmental influences and physical, chemical, electrical and mechanical stresses imposed on the finished product. Some of the basic scientific processes involved in durability are discussed, with practical applications in the form of case histories in which the use of additives played a part in enhancing durability. USA

Accession no.804346

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References and Abstracts

Item 39 Rubber and Plastics News 30, No.12, 8th Jan.2001, p.3 REPORT TIES TYRE PROBLEMS TO DESIGN, MANUFACTURING Collins C An internal probe by experts at Bridgestone/Firestone has concluded that there was no single factor that caused the abnormal rate of tread separations in P235/75R15 Firestone Radial ATX, ATX II and Wilderness AT tyres that led the firm to voluntarily recall 6.5 million of them. The company has concluded that a combination of design factors, external factors such as low inflation pressure and certain manufacturing factors at the company’s Decatur, Ill., plant, in extreme cases and working together, have contributed to the phenomenon. BRIDGESTONE/FIRESTONE INC. USA

Accession no.803708 Item 40 Kautchuk und Gummi Kunststoffe 53, No.12, Dec. 2000, p.694/700 INSTRUMENT TO EVALUATE DAMAGE IN STEEL BELTED RADIAL TRUCK TIRES dos Reis H L M; Golko P J Illinois University at Urbana-Champaign The acousto-ultrasonic approach to damage detection in tyres is described, with reference to the development of an air-coupled transducer, which replaces a contact ultrasonic rolling transducer in the evaluation and detection of ply cord fatigue damage in steel-belted radial truck tyres. Such damage, known in the retreading industry as zipper failure mode occurs around the radius of the tyre in the sidewall flex area. By reducing the number of moving parts in the sensing unit, the instrument increased its robustness to better endure the environment of a new tyre or retreading facility for on-line inspection of new and used tyres. Results are given of a feasibility study involving two tyres, - one with seeded defects, and the other with field fatigue damage. 27 refs. USA

Accession no.799299 Item 41 Polymer Degradation and Stability 71, No.1, 2001, p.15-30 WEAR-OUT APPROACH FOR PREDICTING THE REMAINING LIFETIME OF MATERIALS Gillen K T; Celina M Sandia National Laboratories The principles underlying the above wear-out approach, which is based on the Palmgren-Miner concept that degradation is cumulative and that failure results directly from the accumulation of damage with time, are reviewed and the application of these principles to materials in

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temperature environments is demonstrated. Analyses of experimental wear-out results for a nitrile rubber where time-temperature superposition is valid and for EPDM where it is invalid are presented and discussed. 18 refs. USA

Accession no.796617 Item 42 European Rubber Journal 182, No.11, Nov.2000, p.22/8 EPDM COMPOUNDS FOR COOLANT HOSE UNDER SCRUTINY White L This article is actually one long article and several smaller ones, all relating to automotive coolant hoses. They discuss: EPDM as the material of choice, sulphur curing, peroxide cured coolant hoses, electrochemical degradation (ECD), peroxide evaluations, ECD testing, coagents and peroxides needed to meet VW specification, carbon black morphology, and problem areas in peroxide curing. DSM ELASTOMERS BV; AKZO NOBEL POLYMER CHEMICALS; AVON RUBBER; CABOT CORP.; SARTOMER CO. EUROPEAN COMMUNITY; EUROPEAN UNION; FINLAND; NETHERLANDS; SCANDINAVIA; WESTERN EUROPE

Accession no.795699 Item 43 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 101 SOLVING PROBLEMS IN RUBBER FORMULATIONS WITH ANALYTICAL CHEMISTRY Dlunzneski P R Hercules Inc. (ACS, Rubber Div.) Analytical techniques available to the rubber compounder are reviewed. Such techniques can be used in troubleshooting problems and formulation experimentation. The various spectroscopic, chromatographic, and thermo-analytical techniques are described, with details of how they can be applied to solve problems in rubber compounding. USA

Accession no.794199 Item 44 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 82 RADIAL SEAL FORCE RETENTION. PART 1: METHODOLOGY Clark R C; Getz N; Witte J SHAMBAN Seals

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References and Abstracts

(ACS, Rubber Div.) Details are given of a test method, developed to meet the more demanding requirements of seals used in aerospace applications, with particular reference to the effects of low density phosphate ester hydraulic fluids and red oils over a long period. These fluids can cause excessive swelling or shrinkage of O-rings or custom seals in their glands, which may result in a gain or loss of retained seal force that over time may pose a critical failure mechanism. This paper presents an applied approach incorporating ‘radial seal force’ to obtain uniformly consistent, performance-capable materials in O-ring and custom configurations. USA

Accession no.794181 Item 45 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 80 NON-LINEAR FINITE ELEMENT MODELING OF ELASTOMER SEALS Pannikottu A; Sadon S; Karmakar U Akron Rubber Development Laboratory Inc. (ACS, Rubber Div.) A new continuous compression stress relaxation test method has been developed for evaluating elastomeric materials for sealing applications. During a test, the elastomer component is compressed at various strain levels under precise displacement control. The sealing force is recorded continuously at a finite time interval. The measurement technique is claimed to be suitable for diagnosing seal failure. The stress decay of sealant materials is modelled using finite element method for both constant and cyclic temperature conditions. The timedependent elastic behaviour of sealant materials is modelled using the finite-strain viscoelasticity theory. The stress relaxation results from FEA are shown to be consistent with the experimental measurements. Materials tested include fluoroelastomers, polybutadiene, EPDM, and hydrogenated nitrile rubber which were compounded for seal and gasket applications. 4 refs. USA

Accession no.794180 Item 46 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 67 CRACKING ENERGY DENSITY AS A PREDICTOR OF FATIGUE LIFE UNDER MULTIAXIAL CONDITIONS Mars W V Cooper Tire & Rubber Co. (ACS, Rubber Div.) Rubber parts in service often experience complex strain histories that can cause mechanical failure. The ability to

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predict the effects of such complex strain histories on fatigue life is therefore seen as crucial in the design of rubber components. A new parameter, the cracking energy density, representing the available energy density of a given strain state and crack orientation, has been proposed as an at-a-point parameter for correlating fatigue crack initiation life. This paper presents results of cyclic, combined tension/torsion fatigue experiments, and compares them with prediction based on this new parameter. The ability of cracking energy density to predict the fatigue life and cracking plane is evaluated for both in-phase and out-of-phase histories of combined axial and shear strain. 16 refs. USA

Accession no.794169 Item 47 158th. ACS Rubber Division Meeting - Fall 2000. Conference preprints. Cincinnati, Oh., 17th.-19th. Oct. 2000, paper 47 OPTIMIZING RUBBER PRODUCTS VIA COMPOUND CHARACTERIZATION AND COMPUTER MODELING Chouchaoui B Windsor Industrial Development Laboratory Inc. (ACS, Rubber Div.) This paper describes some tests on rubber, which are necessary to build computer models which can be used to simulate the performance of finished rubber goods. It also presents several analytical studies successfully carried out by WIDL on behalf of rubber moulders in Canada and the USA. These examples demonstrate the usefulness and accuracy of virtual testing. Tests are also presented which are aimed to ensure the accuracy of virtual prototypes based on finite element analysis. 14 refs. USA

Accession no.794152 Item 48 High Performance Elastomers 2000. Conference proceedings. Berlin, Germany, 10th-11th Oct.2000, paper 4 ELASTOMERS IN HOSTILE ENVIRONMENTS Campion R P; Morgan G J Materials Engineering Research Laboratory Ltd. (Rapra Technology Ltd.; European Rubber Journal) For most applications involving elastomeric components, successful service of the elastomer will depend on different overriding factors concerning deformation mode and environment, as will any approaches to life prediction with regard to material or component. Such predictions are required because elastomers can deteriorate in hostile environments, but the degree of deterioration varies immensely between different elastomers. However, it may not always be possible to predict the time to ultimate

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References and Abstracts

failure. Instead one might foretell from accelerated test observations a time when a known, acceptable, key property level still applies to the elastomer at service conditions. Detailed descriptions of a range of approaches to life prediction for elastomers both from a general viewpoint in a variety of environments and using various case studies have previously been given. By selecting from the previous descriptions and presenting further relevant data, an attempt is made to focus on factors involved when the environments surrounding the elastomers are hostile, and to indicate possible approaches for making reasonable estimations of how long adequate levels of relevant properties might be retained during service. It is helpful to be aware of the basic molecular structure of these materials. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.792366 Item 49 International Polymer Science and Technology 27, No.9, 2000, p.T/33-40 DEGRADATION AND LIFETIME OF RUBBER VIBRATION INSULATORS FOR VEHICLES Akema T The need for a method of predicting degradation in rubber products is discussed, with particular reference to automotive engine mounts. Current warranty periods worldwide are summarised to provide a basis for anticipated failure rates of automotive components. In particular, predicted thermal degradation lifetime and reliability evaluation techniques are examined which focus on the relationship between various rubber components and other typical degradative factors in the automotive environment, and which take into consideration the combined degradation by heat and vibration in engine mounts. 2 refs. Translation of Nippon Gomu Kyokaishi, No.11, 1998, p.703. JAPAN

Accession no.791816 Item 50 Tire Science and Technology 28, No.3, July-Sept. 2000, p.196-208 EFFECT OF FATIGUE STEP LOADING SEQUENCE ON RESIDUAL STRENGTH Sun C; Gent A; Marteny P Goodyear Tire & Rubber Co. The applicability of Miner’s rule to typical rubber compounds subjected to repeated tensile strains was evaluated. Tests were carried out on NR and SBR filled with carbon black to determine the effects of loading sequence on residual energy to break, breaking elongation and flaw growth. A model is proposed to predict flaw (crack) growth under mixed strain cycles and the influence of loading sequence on the order of durability rankings

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of the rubber materials investigated. It was found that Miner’s rule did not hold for the fatigue failure of these rubber compounds but the relative rankings of the rubber compounds remained the same in both step-up and stepdown strain sequences. (Eighteenth annual conference of the Tire Society, Akron, Ohio, 27-28 April, 1999). 5 refs. USA

Accession no.791577 Item 51 Industria della Gomma 44, No.4, May 2000, p.19-20 Italian ARTIFICIAL VISION, REAL CONTROL Salva D Doss An examination is made of the use in quality control of artificial vision techniques using a video camera and image processor. Applications in the inspection of rubber seals are described. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.790898 Item 52 Rubber and Plastics News 30, No.3, 4th Sept. 2000, p.54 NYLON TIRE CAP PLIES DRAW MORE SCRUTINY Moore M The function and necessity of nylon cap plies is discussed, with reference to the recent recall of Bridgestone/ Firestone’s ATX, ATX II and Wilderness tyres following a spate of accidents involving tread separation. According to the company, nylon cap plies are used almost exclusively on high speed-rated tyres. However, the dispute continues, especially since the company is accused of mislabelling the Wilderness tyres for Ford Motor Co in Venezuela, as having the cap plies requested by Ford. An earlier court case is referred to when the driver, rendered quadriplegic by an accident in which the tread separated, was awarded 6.8 million US dollars against Continental AG. The Wisconsin court in this case described a cap ply as ‘an additional adhesive to prevent belt separation’. Other opinions relating to the use of cap plies are reported. BRIDGESTONE/FIRESTONE INC. USA; VENEZUELA

Accession no.788988 Item 53 Rubber and Plastics News 30, No.3, 4th Sept. 2000, p.1/60 COUNTING ON SAFETY. AIRCRAFT TIRES MEET STRINGENT STANDARDS Dawson B

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Comments are reported from companies involved in the aircraft tyre industry, which aim to reassure the user about the safety of such tyres following the recent Air France Concorde crash which resulted from tyre debris puncturing the plane’s fuel tank. Test and inspection methods used, the use of retreaded tyres, and the trend towards the use of radial tyres are discussed. AIR FRANCE INDUSTRIE; US, FEDERAL AVIATION ADMINISTRATION USA

Accession no.788963 Item 54 IRC 2000. Conference proceedings. Helsinki, Finland, 13th-15th June 2000, paper 65 FUTURE DIRECTIONS IN MATERIALS EVALUATIONS FOR CRITICAL OFFSHORE APPLICATIONS Stevenson A (Nordic Council of Rubber Technology) Elastomeric components are finding increasingly critical use in a number of applications in offshore oil and gas engineering projects. These include load bearing applications, such as flexelements for deepwater tension leg platforms, hoses and swivel joints in floating production systems, wellhead sealing and downhole sealing. It is increasingly unacceptable to experience unexpected failure due to the cost of downtime and maintenance operations. Qualification of materials is therefore of concern and there have been some costly mistakes in the past, from which the appropriate lessons have not always been learned. Some of the applications and the materials evaluation requirements for long and safe life are discussed. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.787099 Item 55 Tire Technology International 2000, p.59-66 IN FULL BLOOM - FINDING ALTERNATIVES TO WAXING OVER THE CRACKS Hong S W; Greene P K; Lin C Uniroyal Chemical Co. Substitutes for wax to provide protection of tyre sidewalls against static ozone cracking are examined. The use of low levels of wax or its complete elimination in the tyre sidewall by combinations with dialkyl paraphenylene diamine (77PD) or 2, 4, 6-tris - (N-1, 4 dimethyl pentylp-phenylene diamino) 1, 3, 5 triazine (TAPDT) is discussed for the long term resistance to dynamic ozone crack resistance. In addition, a mechanism is proposed to explain how ozone reacts with antiozonants, which involves a scavenging function. 5 refs. USA

Accession no.785679

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Item 56 Tire Business 18, No.9, 17th July 2000, p.10 NEW FOR THE 21ST CENTURY: IT’S A GAS Fisher P J It is claimed that the new technological advancement in tyres may be the use of nitrogen instead of air to inflate tyres. As air migrates through the tyre liner at a rate of about 2psi per month, it is carrying moisture with it which contaminates the steel and initiates the growth of rust in the steel body plies. Oxygen also reacts with rubber, oxidizes it and can make it less flexible and weaker. Nitrogen permeates the tyre 30-40% slower than the oxygen in the air and does not carry any water. It is chemically inert and does not react with rubber. All that is required to make nitrogen is an air compressor with a membrane system to separate out the oxygen, water vapour and carbon dioxide. Today, several companies are marketing affordable systems to produce nitrogen using a conventional air compressor. USA

Accession no.785010 Item 57 Rubber World 222, No.2, May 2000, p.25/7 DEDICATED, AUTOMATIC TIRE SIDEWALL INSPECTION O’Neil E Bytewise Measurement Systems USA A US manufacturer of precise non-contact product and process measurement systems, Bytewise Measurement Systems, has introduced a dedicated tyre sidewall bulge/ dent inspection system. Full details are given under the headings: why measure tyre sidewalls?, principle of operation, benefits of laser measurement technology, letter elimination software, and summary. USA

Accession no.783618 Item 58 Rubber and Plastics News 29, No.22, 29th May 2000, p.12-4 REDUCING IRIDESCENCE IN EPDM WEATHERSTRIPPING Larson L C; Danilowicz P A Struktol Co.of America Automotive manufacturers continue to demand improvements in the colour stability of their weatherstripping. The iridescence sheen phenomenon occurs particularly in EPDM when the fabricated articles are exposed to UV light and ozone. Recently a unique new filler called “Neuburg siliceous earth” has arrived in the North American marketplace from Europe. This study compares the influence of these unique fillers with those presently used in North America. This study will also

© Copyright 2002 Rapra Technology Limited

References and Abstracts

provide compounders with key compounding suggestions that will aid in the reduction of iridescence, improve profile aesthetics and increase plant productivity. 4 refs. USA

Accession no.780107 Item 59 Rubber India 52, No.4, April 2000, p.17-22 PROCESSING CHALLENGES TO ACHIEVE QUALITY, PRODUCTIVITY AND VALUE FOR THE PRODUCT Ramdas S Fenner India Ltd. Consideration is given to factors affecting the quality, productivity and value of rubber products with reference to processing methods. In particular, mixing, extrusion, moulding, transfer moulding, metal to rubber bonding, process control, FMEA, value engineering, quick tool changes, and prototyping are discussed.

ADVANCES AND CHALLENGES IN LONGTERM SERVICE LIFE PREDICTION OF ELASTOMERIC ENGINEERING COMPONENTS Harris J A; Hawkes J R; Campion R P; Derham C J Materials Engineering Research Laboratory Ltd. (ACS, Rubber Div.) Various mechanisms that may dictate the service life of elastomeric engineering components are identified and discussed. For life prediction, predictive modelling and accelerated testing are required. Predictive models currently available for crack growth, creep/stress relaxation, fluid compatibility and chemical ageing are discussed. Case studies are used to illustrate the use of predictive models and accelerated testing for various types of component. These include the use of a fracture mechanics approach for crack growth prediction in an automotive type mount and the Arrhenius approach and other factors on sealing systems for oil and gas. The challenge is to develop life prediction methodology to account for some of the complex aspects of real service environments. 16 refs.

INDIA

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

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Accession no.771678

Item 60 Journal of Testing & Evaluation 27, No.4, July 1999, p.249-65 NEW DYNAMIC WIND LOAD CYCLE TO EVALUATE MECHANICALLY ATTACHED FLEXIBLE MEMBRANE ROOFS Baskaran A; Yin Chen; Vilaipornsawai U Canada, National Research Council

Item 62 157th ACS Rubber Division Meeting - Spring 2000. Preprints. Dallas, Tex., 4th-6th April 2000, paper 38 REVIEW OF POLYMER LIFE ESTIMATION USING VARIABLE TEMPERATURE/STRESS ACCELERATION METHODS Vicic J; Maligas M; Jones W; Janoff D Cameron; FMC Corp. (ACS, Rubber Div.)

A report is presented on progress towards developing test procedures for certifying roofing systems under dynamic wind loads by the National Research Council of Canada’s Special Interest Group for Dynamic Evaluation of Roofing Systems(SIGDERS). Wind tunnel investigations were carried out using two flexible roofing membranes, PVC and EPDM. Using the wind tunnel pressure records as source data and comparing the membrane responses of PVC with EPDM, SIGDERS developed a dynamic load cycle. With input from industries, building owners and roofing associations, the developed load cycle was generalised and extended to evaluate the ultimate strength of flexible membrane roofs. To validate the newlydeveloped load cycle, several membrane roofing systems were investigated and then reported separately. The SIGDERS load cycle in a laboratory mimicked failure modes similar to those observed in the field. 23 refs. CANADA

Accession no.776393 Item 61 157th ACS Rubber Division Meeting - Spring 2000. Preprints. Dallas, Tex., 4th-6th April 2000, paper 40

© Copyright 2002 Rapra Technology Limited

Elastomers are used in many critical service applications that require long, trouble-free life such as seals, gaskets, bridge pads, tyres, medical components and rocket fuel binders. An estimate of long-term durability or the time to failure for materials and components presents a challenge to both scientists and technologists that work with these materials. Interest in this area is high as evidenced by the fact that the American Petroleum Institute Committee 6 and the National Association of Corrosion Engineers Committee T1-G have task groups working on developing accelerated life estimation tests for elastomer seals. It is shown how thermal acceleration tests based on Arrhenius’ theory and modifications by other researchers such as Zhurkov that include the effect of applied stress may be used to estimate the long-term property changes in elastomers. A brief historical background of work in this area and its implications are included. Current industrial practices that use thermal acceleration are reviewed. Some examples of thermal acceleration techniques applied to failure life estimation for actual components are examined. 19 refs. USA

Accession no.771676

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Item 63 157th ACS Rubber Division Meeting - Spring 2000. Preprints. Dallas, Tex., 4th-6th April 2000, paper 37 SEAL LIFE IN REAL LIFE Page N Walker J., & Co.Ltd. (ACS, Rubber Div.) The practical analysis of seal failure modes and mechanisms has previously been described. Firstly, failure modes are summarised, followed by describing the remedial actions which may be taken to avert failures such as those caused through housing, application and other non-time/temperature dependent effects. Secondly, a method for the prediction of time/temperature dependent elastomer degradation is presented and its practicality is discussed. Finally ‘good practice’ is shown to be an essential tool for maximising seal performance against a background that the majority of seal failure is still unpredictable, although in many cases avoidable. Pragmatic and predictive approaches to minimising seal failure are compared. 2 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.771675 Item 64 Rubber World 221, No.5, Feb.2000, p.55-8 REVERSION RESISTANCE OF ENGINE MOUNTS Graf H J; Sayej E Cooper Standard Automotive Reversion is defined as the softening and weakening of natural rubber vulcanisate when the curing operation has been continued too long. This article describes experimentation carried out on a natural rubber engine mount with a reversion-resistant polychloroprene coating. Materials and methods are detailed, results are presented and discussed, and conclusions drawn. 18 refs. USA

Accession no.770976 Item 65 Rubberchem ’99. Conference proceedings. Antwerp, Belgium, 22nd-23rd Nov.1999, paper 14 AMINIC ANTIDEGRADANTS: DISCOLOURING TRANSFORMATION PRODUCTS AS ACTIVE COMPONENTS IN THE INTEGRAL STABILISING MECHANISM IN RUBBER Prosisil J; Habicher W D; Nespurek S Czech Republic, Academy of Sciences; Dresden, Technische Universitat (Rapra Technology Ltd.) Aromatic amines and diamines and planar heterocyclic amines rank among the most important rubber chemicals.

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Depending on their structure (inherent chemical efficiency), they act as efficient antioxidants, antifatigue agents and/or antiozonants. Some of them combine these activities in one molecule. The unique antidegradant properties are based on the presence of the secondary amine functional group greater than NH in the parent additive and amine transformation products. Sacrificial consumption of amines accounting for these transformation products is a consequence of active stabilisation of the rubber matrix by amines (scavenging) of ROO. radicals, contribution to deactivation of hydroperoxides ROOH, and reaction with ozone and/or ozonides. Transformation products are mostly coloured derivatives of quinone imine and more complicated compounds derived from them. Their formation cannot be avoided. Quinone imines contribute to the overall stabilisation performance of amines by scavenging carbon-centred free radicals. This unique property is important for the antifatigue effect. Moreover, the reaction is associated with a partial regeneration of the secondary amine moiety greater than NH. The integral mechanism of sacrificial transformations of amines is outlined. 9 refs. CZECH REPUBLIC; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.769256 Item 66 Machine Design 72, No.6, 23rd March 2000, p.98 HANDBOOK GUIDES O-RING DESIGN A review is presented of the Parker O-Ring Handbook, a manual detailing o-ring design over 11 chapters. Technical information is provided on topics such as chemical compatibility, O-ring specifications, and sizes and tutorial chapters include O-ring elastomers, applications and static and dynamic sealing. Other topics covered include material selection, installation, the effects of friction and O-ring failure analysis. PARKER HANNIFIN CORP., O-RING DIV. USA

Accession no.768062 Item 67 Shawbury, 2000, pp.ii, 170. 30cms. 11/4/00. 93T NATURAL AGEING OF RUBBER - CHANGES IN PHYSICAL PROPERTIES OVER 40 YEARS Brown R P; Butler T Rapra Technology Ltd. This report is an output from the Weathering of Elastomers and Sealants project which forms part of the UK government’s Department of Trade and Industry’s Degradation of Materials in Aggressive Environments Programme. Rapra Technology Limited has just completed a comprehensive natural ageing and physical testing programme on 19 rubber compounds, stored in controlled conditions, for a period of 40 years. This is

© Copyright 2002 Rapra Technology Limited

References and Abstracts

believed to be the most extensive such study ever carried out. The results of this unique programme are published in this report. Accession no.766772 Item 68 Rubber Technology International 1999, p.48-51 KRATON IR, A PURE ALTERNATIVE Migchels P Shell Chemicals Kraton synthetic isoprene rubbers are offered as an alternative to natural rubber products, and provide an option for use in applications requiring no discolouration, odour and a high degree of purity. The benefits are described of two currently available synthetic isoprene processing technologies, - Kraton anionically polymerised IR marketed by Shell and Ziegler-Natta IR, with reference to their ability to reduce problems of discolouration, odour and adverse skin reactions, and to improve the overall quality and performance of finished products without sacrificing the traditional benefits of NR. 2 refs. Accession no.763106 Item 69 Adhesion ’99. Conference Proceedings. Cambridge, UK, 15th-17th Sept.1999, p.55-60 TIME DEPENDENT MECHANICAL FAILURE OF STRONG ELASTOMER-TO-METAL BONDS: CHEMICAL OR PHYSICAL MECHANISM? Albihn P; Chapman A V; Lake G J; Lawrence C C Swedish Institute for Fibre & Polymer Research; Malaysian Rubber Producers’ Research Assn.; East London, University (IOM Communications Ltd.) Studies were made of chemical and physical factors influencing time dependent near-bond failure in NR/steel bonded joints. Chemical studies revealed no evidence to indicate that chemical modifications were substantially weakening the rubber adjacent to the bond. Video observations suggested that a cavitation-like process, probably arising from dilatational components in the stresses near an interface, could lead to time dependent mechanical failure near the bond. 10 refs. TUN ABDUL RAZAK RESEARCH CENTRE EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; SWEDEN; UK; WESTERN EUROPE

Accession no.761623 Item 70 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 70 CRACKING WHILE CURING IN SILICONE SEALANTS Pujol J-M

© Copyright 2002 Rapra Technology Limited

Rhodia Silicones (ACS, Rubber Div.) The cracking of silicone sealants during cure is studied. These elastomers cure slowly at room temperature by diffusion of water vapour from the atmosphere, which initiates hydrolysis and condensation crosslinking reactions. Sealants are used as waterproofing seals in construction. Joint movement due to thermal expansion of building materials lead to extension of seals during cure. Cracks in the seal may appear for movement lower than 10% and may cause seal failure. The effect of movement is examined and characterised for several sealant types. The elongation at the time where the cracks appear varies during the cure. It quickly drops to a low value during the first minutes of curing. While the cure continues, it increases to reach the elongation at break of the cured elastomer. The cracking is related to brittleness of the network obtained during the first crosslinking steps. A model based on water vapour diffusion, hydrolysis and condensation reactions is developed. This model can explain the cracks observed. The crosslinking rate plays a major influence on the curing sealant capability to tolerate movement. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.759664 Item 71 Shawbury, Rapra Technology Ltd., 2000, pp.104. 30 cms. 17/12/99. Rapra Review Rept.111, Vol.10, No.3, 2000. NALOAN POLYMER PRODUCT FAILURE Lewis P R Open University Edited by: Dolbey R (Rapra Technology Ltd.) Rapra.Review Rept.No.11 Case studies are used to demonstrate failures in polymer products. Aspects of defect analysis considered include the occurrence of recrystallisation, surface contamination, frozen-in strain, mixing efficiency, and formulation problems. Case histories examined include those involving pipes and fittings, storage tanks, and medical products. 383 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.759543 Item 72 Tire Business 16, No.25, 29th March 1999, p.3/19 “GATOR” HUNTING Davis B This article provides information on lorry tyre failure in the USA, with figures taken from a recently-published report by a tyre industry task force. The reports states

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References and Abstracts

consequent reduction in the transparency of the rubber provides a facile method for quantifying the ambient ozone concentration. The rate at which opacity develops is linearly dependent on the amount of ozone, and increases with increasing strain. This method of detecting atmospheric ozone has high sensitivity (1 ppb), a broad dynamic range, and is unaffected by the presence of other chemicals. The surface morphology of exposed material can be interpreted in terms of crack nucleation and growth. 31 refs.

that both new and retread lorry tyres are failing at a faster rate than four years ago, partly because of the increased speeds allowed in some states, and partly because of low pressure resulting from poor maintenance. BRIDGESTONE/FIRESTONE INC.; CONTINENTAL GENERAL TIRE; GOODYEAR; HAWKINSON COMPANIES; HERCULES TIRE & RUBBER CO.; MICHELIN NORTH AMERICA; OLIVER RUBBER CO.; TEKNOR APEX CO.; US, TIRE RETREAD INFORMATION BUREAU; YOKOHAMA TIRE CORP.

USA

USA

Accession no.758356

Accession no.759395 Item 73 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 65 HOW TO AVOID OZONE CRACKING - A SOLUTION FOR WHITE AND COLOURED RUBBER GOODS Jeske W Bayer AG (ACS, Rubber Div.) The demand for white and coloured rubber articles for various applications is steadily growing. Rubbers are, depending on their content of olefinic double bonds, very sensitive to ozone, and hence effective antiozonants are necessary. Due to their discolouring and staining effect, para-phenylenediamine antiozonants cannot be used in compounds for white or coloured articles. A survey of the effectiveness of Vulkazon AFS, a cyclic acetal providing excellent ozone protection in coloured compounds based on various elastomers, is presented. The effectiveness of the cyclic acetal is compared with paraphenylenediamine antiozonants in chloroprene, butyl and halobutyl compounds. The effect in diene rubbers, where the cyclic acetal has to be used in combination with waxes, is investigated. Cyclic acetals do not affect the peroxide cure like other antiozonants and hence the material has also been tested in peroxide-cured cable jacket compounds based on a saturated elastomer. 2 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.758359 Item 74 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 62 OZONE DETECTION BY CRACK-INDUCED OPACITY IN RUBBER Mott P H; Roland C M US, Naval Research Laboratory (ACS, Rubber Div.) Initially transparent polybutadiene develops micron-sized surface cracks when stretched and exposed to ozone. The

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Item 75 International Polymer Science and Technology 26, No.3, 1999, p.7-14 CRACK FORMATION AND GROWTH UNDER THE INFLUENCE OF HIGH GROUND SURFACE OZONE CONCENTRATION Ehrhardt D The influence of ozone on the weathering of tensilestressed, carbon black-filled and unfilled natural rubber, styrene-butadiene rubber and butadiene acrylonitrile rubber, some of which contained a protective agent based on N, N’ substituted p-phenylene diamines and a microcrystalline wax, was determined under conditions of continuous weathering, with the samples being exposed for the entire period May to September/October; and under high-pressure weathering, where the daily maximum for the half-hour values of ozone concentration was at least 80 mg/cu m, the maximum daily air temperature was at least 18C, and the total daily sunshine duration at least 10 h. The samples were evaluated from considerations of the initial elongation, the number of cracks, and the crack depth. It was concluded that only those materials with an effective protective system or based on ozone-resistant rubbers could withstand effects of ozone during episodes of summer smog. 20 refs. Translation of Gummi Fasern Kunststoffe, No.2, 1999, p.109. Accession no.756152 Item 76 Rubber and Plastics News 2 21, No.2, 25th Oct.1999, p.6 STEER-AXLE RETREAD BAN SOUGHT Mikolajczyk S J In May, an accident in Montana caused by a tyre blowout on a concrete mixer truck resulted in the death of two women. A lawsuit is being filed on behalf of the victims’ husbands seeking unspecified damages for negligence and product liability. The retreaded tyre was fitted on the steer axle of the truck and when the tyre blew, the driver lost control of the vehicle and it collided head-on with the women’s car. The attorneys handling the case hope it will spur efforts nationwide to get retreaded tyres banned from use on commercial vehicles’ steer axles.

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References and Abstracts

LES SCHWAB TIRE CENTERS INC. USA

Accession no.754185 Item 77 Gummibereifung 73, No.8, Aug.1997, p.65-6 German TRADE SUMMIT MEETS AT STAHLGRUBER Mutz K In 1997 the tyre firm Tip Top Stahlgruber and the Stahlgruber Stiftung (Foundation) hosted the third round-table conference for a pool of specialist representatives from the German tyre industry and its trade associations for an exchange of experiences and ideas. Topics covered damage to tyres, involvement of customers, repair to damaged tyres, mobile tyre repair support call-out services and aspects of retreads regarding tyre damage, as well as the use of steel cord patches, blow-outs and assistance in handling punctures, including mobile puncture sets like the Mercedes Benz Tirefit which should replace the spare tyre in the future. The numerous world-wide tyre firms contributing to this exchange are listed. TIP TOP STAHLGRUBER; STAHLGRUBER STIFTUNG EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.753826 Item 78 Gummibereifung 73, No.7, July 1997, p.78 German TYRE CHECK CAN SAVE LIVES Mutz K Statistical evidence for road deaths in Germany resulting from faulty tyres is examined as background to regular momentary tyre checks advocated by Germany’s Bundesverband Reifenhandel und Vulkaniseur-Handwerk e.V. (BRV). Issues include low tyre pressure, tyre damage, indentations in the running surface or bits of rubber separated off. The BRV along with the TUeV for Rhineland have published free safety information on tyre care and many tyres traders offer free tyre safety checks. BUNDESVERBAND REIFENHANDEL UND VULKANISEURHANDWERK E.V.; TUEV EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.752478 Item 79 Rubber World 220, No.6, Sept.1999, p.27-30 MORE ADVANCED WAY TO DESIGNING RUBBER PRODUCTS

© Copyright 2002 Rapra Technology Limited

Chouchaoui B Windsor Industrial Development Laboratory An alternative to trial and error in designing rubber products is virtual testing, the computer testing of products and processes. This article describes testing rubber towards building computer models. Studies completed include leakage of crimp on a composite hose, a cracked T-joint in a piping system, the closure of an electrical connector, collapse of an underhood latch, dampening a tractor cab, design of a pad for rail crossings and optimisation of a dishwasher seal. 14 refs. CANADA

Accession no.751229 Item 80 Rubber and Plastics News 2 20, No.23, 16th Aug.1999, p.7 INVESTIGATION BEGINS ON POSSIBLE FUEL HOSE LEAKAGE Moore M Problems with leaking under-the-bonnet hose or hose fittings on the 1993-1997 Mercury Villagers minivans and Ford SVT Mustang Cobra model years 1994-98 are reported. The NHTSA is investigating complaints of fuel leaks in the former and problems with incompatibility of OE front brake hoses and aftermarket high speed front brake linings on the Cobras. Brief details are given. MERCURY VILLAGES; US, NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION USA

Accession no.750794 Item 81 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 59, pp.38 INFLUENCE OF COMPOUNDING MATERIALS ON TIRE DURABILITY Niziolek A W; Jones R H; Neilsen J G Bayer Corp. (ACS, Rubber Div.) The influence of polymers and additives on the service life of non-tread tyre components is discussed on the basis of results obtained from studies of inner liner, belt and sidewall compounds. The effects of the bromine content of bromobutyl rubbers on the performance of inner liners, and of sulphenamide accelerators on the adhesion of NR belt compounds to brass coated steel cords were investigated. The mechanical properties and ageing and ozone resistance of black sidewall compounds consisting of NR blends with neodymium catalysed polybutadiene protected with different antioxidants and antiozonants were also evaluated. 5 refs. USA

Accession no.749872

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Item 82 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 56, pp.20 STRESS-INDUCED PHENOMENA IN ELASTOMERS, AND THEIR INFLUENCE ON DESIGN AND PERFORMANCE OF O-RINGS Morgan G J; Campion R P; Derham C J Materials Engineering Research Laboratory (ACS, Rubber Div.) The effects of stresses and associated strains on O-rings used in sealing pressurised fluids are discussed. Results are presented of studies of ageing and property changes of stressed and unstressed elastomers exposed to a hot aqueous solution of ethylene diamine, transient effects of temperature on sealing force, and the influence of memory effects on gas induced fracture by explosive decompression. Materials examined included fluoroelastomers, nitrile rubber and hydrogenated nitrile rubber. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.749869 Item 83 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 42, pp.8 AUTOMATIC X-RAY INSPECTION FOR THE TIRE INDUSTRY Neuhaus T Yxlon International Inc., LumenX Div. (ACS, Rubber Div.) Automatic X-ray inspection using linear diode array imaging systems is discussed as a quality control method for tyres. LUMENX USA

Accession no.749858 Item 84 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 40, pp.24 APPLICATIONS OF ULTRA-HIGH RESOLUTION EVANESCENT MICROWAVE IMAGING PROBE IN TIRE AND RUBBER MEASUREMENTS Tabib-Azar M; Mowdood S K; LeClair S Case Western Reserve University; Pirelli Tire LLC; US, Air Force Research Laboratory (ACS, Rubber Div.) The use of evanescent microwave probes for imaging nonuniformities in a variety of materials is discussed. Applications of this technique are illustrated by a number of examples, including the study of the surface structure of EPM samples and damage detection in tyres. 25 refs.

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WRIGHT-PATTERSON AIR FORCE BASE USA

Accession no.749856 Item 85 155th ACS Rubber Division Meeting, Spring 1999. Conference Preprints. Chicago, Il., 13th-16th April 1999, Paper 39, pp.19 INSTRUMENT TO EVALUATE DAMAGE IN STEEL BELTED RADIAL TRUCK TIRES dos Reis H L M; Golko P J Illinois, University (ACS, Rubber Div.) Details are given of a prototype instrument which uses an acousto-ultrasonic approach to detect and evaluate ply cord fatigue damage, a likely cause of the zipper mode of failure in steel belted radial truck tyres. Using an ultrasonic roller transducer as the sending transducer and an air coupled receiving transducer, the instrument is capable of producing colour coded scans, thereby reducing the possibility of operator error which could result in damaged tyres being placed in service. Results are presented for the application of the instrument to damage detection in a new tyre having seeded defects in the sidewall area and a used tyre with field fatigue damage. 26 refs. USA

Accession no.749855 Item 86 Rubber and Plastics News 28, No.26, 26th July 1999, p.1/10 SYNTHETIC FUTURE Moore M NR latex has long been the barrier protection of choice for physicians, nurses, dentists and other healthcare professionals. However, estimates of the prevalence of latex allergies and sensitisation among healthcare workers ranges from 5 to 17%. Comfort and cost are the main reasons latex remains dominant in the barrier protection market. However, in a small but growing number of hospitals, the idea of an eventual latex-free environment has taken root and those institutions are replacing natural with synthetic rubber in more and more applications. JOHNS HOPKINS MEDICAL INSTITUTION USA

Accession no.747150 Item 87 Tire Technology International Sept.1999, p.46/53 CRASH! Newland G Newlaw Associates Tyres are arguably the most important feature on a vehicle for ensuring the safety of drivers, passengers and all road

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References and Abstracts

users. They are the vehicle’s only contact with the road surface for acceleration, cornering and braking, yet they are the most consistently abused and neglected part of a vehicle. Accurate forensic examination of tyres after a car crash requires more than just a rudimentary understanding of how they are made. With experience, important clues as to the causes of crashes can be found. Such examination requires knowledge of the manufacturing processes and materials involved, and the way each component works in relation to the other components. It requires knowledge of all the external factors that affect tyre performance, and how a tyre behaves when these other influences are brought to bear. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.745577 Item 88 Rubber and Plastics News 28, No.24, 28th June 1999, p.1/21 STUDY FINDS BREAST IMPLANTS DON’T CAUSE ILLNESS Moore M Silicone gel breast implants do not cause cancer or systemic disease in women, according to a governmentfunded study. But other complications, such as implant rupture and deflation or contraction of the fibrous tissue around the breast, are fairly common and need to be studied further, concluded the three-member panel organised under the auspices of the Institute of Medicine, the medical arm of the National Academy of Sciences. Dow Corning, inventor of silicone implants, said the report ‘provides additional solid evidence that breast implants do not cause disease’. The panelists, who have no connection with any parties in the silicone implant dispute and worked without compensation, reviewed more than 3, 000 publications on implants, giving particular weight to peer-reviewed scientific articles. All the evidence indicates that rupture, tissue contraction and other local complications resulting in pain, disfigurement or infection are the main problems with silicone implants, according to the study. Details are given. US, NATIONAL ACADEMY OF SCIENCES; US, INSTITUTE OF MEDICINE; DOW CORNING CORP. USA

Accession no.745570 Item 89 International Polymer Science and Technology 26, No.1, 1999, p.T/38-41 PROBLEMS WITH THE USE OF PMTP-150 PIPELINES WITH BELL AND SPIGOT JOINTS IN A COLD CLIMATE Petrova N N; Popova A F; Cherskii I N; Kovalenko N A Russian Academy of Sciences In 1996, the Talakan-Vitim oil pipeline was built and put into service. The PMTP-150 long-distance pipeline

© Copyright 2002 Rapra Technology Limited

consists of pipes of 6 m length, joined with bell and spigot joints sealed with rubber sealing rings. A pipeline design of this kind determines its main advantage - the possibility of mechanised assembly at high speed with a minimum number of engineering personnel. All joints are detachable; the use of welding methods is eliminated. The construction of the Talakan-Vitim oil pipeline was preceded by a long preparatory period, in the course of which the question of the possible use of PMTP-150 pipelines in conditions of the Sakha Republic was tackled. Analysis of design and technical decisions showed that the main obstacle to the use of the pipeline in a cold climate is the inadequate cold resistance of the sealing materials used. The sealing rings regulated by specifications TU 38.105.1962-90 for the sealing of pipe joints are intended for service at temperatures ranging from -40 to +80 deg.C. Storage and transportation of the seals are permitted at temperatures no lower than 30 deg.C. This level of cold resistance of the rubber sealing rings is unacceptable for reliable service in conditions of the Far North. Furthermore, in connection with expiry of the permissible storage times, considerable reduction in the mechanical properties of seals intended for pipeline assembly was found, and therefore the decision was taken to manufacture new sealing elements from rubbers with increased cold resistance. It was proposed that vulcanisate V-14 based on SKN-18 acrylonitrile butadiene rubber be used for the manufacture of sealing rings. 4 refs. RUSSIA

Accession no.745523 Item 90 International Polymer Science and Technology 26, No.1, 1999, p.t/10-2 DETERMINATION OF THE ACTIVATION ENERGY OF HEAT AGEING OF VULCANISATE FROM THE CHANGE IN ITS ELECTRICAL PARAMETERS Meshchaninov S K Ukranian Academy of Sciences Until recently the main factor in the breakdown of solids was considered to be the mechanical load. However, the dilaton theory of strength which has appeared in the past decade has altered these concepts radically. From this point of view, the mechanical load plays only the role of supplier of the energy ‘pumped’ into the dilaton and causing thermal expansion of the bonds up to their breakdown. Thus, the difference between mechanical and other forms of breakdown of solids is removed. The heat ageing of a vulcanisate is one of the most common causes of failure of structural elements manufactured from it. In the general case the heat ageing of a material can be described by a firstorder reaction. 8 refs. RUSSIA

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Item 91 Tire Business 17, No.2, 26th April 1999, p.11 RETREADING’S VERY SURVIVAL THREATENED Fisher P This article supplies details of the issues discussed at the annual meeting of the Maintenance Council of American Trucking Association. The article focuses on the latest activities by safety activates to restrict and regulate truck tyre retreads. A study in 1998 of tyre failures revealed that 85% were retreads. An Association of Citizens for Reliable and Safe Highways (CRASH), has launched a major campaign against truck tyre retreads. The article supplies details of the campaign, together with possible repercussions on the truck tyre retread market. AMERICAN TRUCKING ASSOCIATION MAINTENANCE COUNCIL; CRASH USA

Accession no.742250 Item 92 Revue Generale des Caoutchoucs et Plastiques No.775, March 1999, p.57-62 French DEFECTS IN THE EXTRUSION OF PROFILES Del Peso R; Karam S; Aubin C IFOCA; LRCCP Results are presented of a study undertaken by LRCCP to determine the influence of extrusion parameters such as die temperature, length, diameter and entry angle on the occurrence of surface defects on EPDM profiles. 2 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.740628 Item 93 Rubber World 220, No.3, June 1999, p.38-40 EP POLYMER SELECTION AND COMPOUND CONSIDERATIONS FOR CHLORAMINE RESISTANCE Mitchell J M The failure of rubber parts used in domestic water applications has been reported from several US states. The complaints involved swelling and cracking and are related to nitrile and ethylene-propylene copolymer type compounds. The failure of the rubber parts coincides with the implementation and use of chloramines as a method of water purification. This investigation was designed to determine if EPDM composition variables influenced resistance to chloramines. Also evaluated were peroxide vs sulphur cure systems, the effect of antioxidants and whether practical compounds can be developed for water systems. 5 refs. USA

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Item 94 Chemie Ingenieur Technik 68, No.3, March 1996, p.219-27 German LEAK RATES OF GASKETS FOR FLANGE CONNECTIONS: INFLUENCING PARAMETERS, REQUIREMENTS, MEASURING TECHNIQUES AND LEAK RATE RELATED GASKET CHARACTERISTICS Kockelmann H Stuttgart, University The use of flow theories in determining the fundamental interrelationships between the leak rate of gaskets for flange connections and the relevant influencing parameters is discussed. The derivation of the basic rule for the transfer of results obtained for special boundary conditions to other conditions is considered and it is shown that the effort involved in gasket testing can be reduced. The relationships between the leak rate of gaskets on the one hand and the internal pressure, temp., medium and gasket thickness on the other hand are presented. The effect of the gasket stress and thickness can be determined only from experimental investigations. The requirements placed on gaskets, the leak rate-related gasket characteristics defined in various standards and the measuring techniques for their determination are discussed. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.739042 Item 95 Gummi Fasern Kunststoffe 52, No.2, 1999, p.109-15 German CRACK FORMATION AND GROWTH UNDER THE INFLUENCE OF HIGH GROUND SURFACE OZONE CONCENTRATION Ehrhardt D Information is given on the frequency, level and formation of ground surface ozone concentrations in Central Europe, and a study is described of the weathering behaviour of various rubber materials (crack initiation and growth) under the effect of ozone. 20 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.738743 Item 96 Rubber World 220, No.2, May 1999, p.50-3 INCREASING THE LIFE OF NR PIPE JOINT RINGS

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References and Abstracts

Hills D A Materials & Quality Consultancy Ltd. The microbiological degradation of NR pipe joint rings was first reported by Leeflang in 1963 and has since been found to be a worldwide problem. This article describes a recent recent research project on the topic. The project was intended to assess the condition of rubber joint rings from many parts of New Zealand, establish the likely life of the improved (post-1970s) rings, and examine the in situ chemical modification of exposed surfaces of the pre1970s rings to increase their longevity. 12 refs. NEW ZEALAND

Accession no.734158 Item 97 Rubber and Plastics News 28, No.17, 22nd March 1999, p.16/9 ANTI-REVERSION AGENTS WORK TOGETHER Kuebler T P Kumho Tire Co.Inc. It is explained that if extreme heat builds up in aircraft tyres it can lead to reversion of the compounds and tyre failure. This paper traces the development of work done in which the combination of two anti-reversion agents used in an aircraft carcass compound provided a synergistic improvement in reversion resistance. Materials and methods are detailed, results are presented and discussed, and conclusions drawn. AMERICAN SOCIETY FOR TESTING & MATERIALS; FLEXSYS USA

Accession no.733809 Item 98 Revue Generale des Caoutchoucs et Plastiques No.771, Oct.1998, p.98/104 French AGEING OF DIENE ELASTOMERS Lemaire J Blaise Pascal, Universite Approaches to the prediction of the long-term ageing behaviour of vulcanised diene rubbers are discussed, and studies of the photooxidative and ozone degradation of polybutadiene, polyisoprene, SBR and nitrile rubber under accelerated artificial ageing conditions are reported. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.732497 Item 99 Polymer Plastics Technology and Engineering 38, No.2, 1999, p.341-50 ABRASION PROPERTY OF EPOXIDISED

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NATURAL RUBBER Poh B T; Razai M J B Sains Malaysia, University The abrasion resistance of two grades of epoxidised NR (ENR 25 and ENR 50) and one grade of SBR is studied using an Akron abrasion tester. An accelerated sulphur vulcanisation system with 2-mercaptobenzothiazole (MBT) as the accelerator is used. Carbon black (N 330), precipitated silica and calcium carbonate are chosen as the fillers. The range of sulphur and filler loadings is from 1 to 5 phr and 10 to 50 phr, respectively. Mixing is done on a two-roll mill. Results obtained show that for all the rubbers studied, the volume loss due to abrasion decreases with increasing sulphur loading and passes through a minimum at about 3 phr of sulphur. This observation is attributed to the changes of crosslink types from monosulphidic to polysulphidic crosslink as sulphur concentration is increased. However, further sulphur loading would cause a ‘tight’ cure, thus increasing the abrasion loss. For sulphur loading less than 3 phr, ENR 25 indicates the highest abrasion loss, followed by SBR and ENR 50. For the filled stock, minimum loss is observed at about 35-40 phr of filler. Reinforcing filler such as carbon black exhibits better abrasion resistance than calcium carbonate, a nonreinforcing filler. The abrasion loss increases at higher filler loading due to the dilution effect of fillers. Ozone plays an important role in the abrasion properties of unsaturated rubbers, as reflected by the higher abrasion loss in the presence of ozone. 17 refs. MALAYSIA

Accession no.732334 Item 100 International Polymer Science and Technology 25, No.9, 1998, p.T/51-7 FATIGUE FAILURE OF ELASTOMERS Fukahari Y The main points of a previous review are given and augmented a discussion of later developments, particularly those reported by the author and co-workers. Topics covered are (1) failure-initiating processes; (2) the size of microcracks; (3) analysis of stress in the vicinity of latent defects in large deformation; (4) limiting negative pressure for microcrack initiation; (5) the crack growth process (fracture mechanical treatment); (6) fracture mechanical treatment of growth initiation; (7) fracture mechanical treatment of fatigue failure; (8) the final step in failure (formation) of irregularities in the fracture surface; (9) simulation of fracture by molecular dynamics; (10) finite element simulation of fracture surface irregularity; (11) synergistic effect of loading and deterioration in fatigue failure; and (12) size of decrease in activation energy due to loading. 32 refs. JAPAN

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References and Abstracts

Item 101 152nd ACS Rubber Division Meeting - Fall 1997. Reprints. Cleveland, Oh., 21st-24th Oct.1997, paper XXV STANDARDS FOR SOME LATEX MEDICAL DEVICES Simon T R TANDA Associates (ACS, Rubber Div.) National and international standards on surgical and examination gloves, condoms and diaphragms are crucial in the manufacture of quality products designed to prevent the spread of infectious diseases or to act as efficient mechanical contraceptives.This article discusses the requirements covered by these standards, such as basic material, dimensions, strength and barrier properties, and the appropriate test methods to determine these characteristics. Also discussed are the differing approaches to sampling methods for these testing procedures as well as the acceptable quality levels for some typical attributes and conflicting features between certain standards. Outlines for possible future developments in the standardisation of these medical devices are given. 20 refs. CANADA

Accession no.721171 Item 102 Nippon Gomu Kyokaishi 71, No.11, 1998, p.690-5 Japanese FATIGUE PHENOMENA OF RUBBER ROLLS Soumiya S A discussion is presented of the mechanisms involved in fatigue phenomena of rubber rolls, and of the determination of the causes and sites of fatigue failure. 8 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.720523 Item 103 Nippon Gomu Kyokaishi 71, No.11, 1998, p.683-9 Japanese FATIGUE LIFE OF AUTOMOTIVE SYNCHRONOUS BELTS Iizuka H Yamagata, University The mechanism of fatigue failure of synchronous rubber belts is discussed. 20 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology.

Item 104 Nippon Gomu Kyokaishi 71, No.11, 1998, p.654-61 Japanese FATIGUE FAILURE OF ELASTOMERS Fukahori Y Bridgestone KK Fundamentals of the mechanics of fatigue failure of elastomers are discussed, and new developments in fatigue failure research are reviewed. 32 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.720518 Item 105 Luntai Gongye 19, No.1, 1999, p.37-9 Chinese IMPORTANCE OF CORRECT TIRE INFLATION PRESSURE Gao Dongping; Li Chengmin Hualin Group Corp.Ltd. Premature failure of tyres was thought to be mainly a result of running at under-inflation pressure. Load tests of 9.00-20 16PR and 9.00R20 16PR tyres at different inflation pressures were carried out. The results obtained showed that the effect of under-inflation was equivalent to that of overload. The combination of overload and under-inflation would result in fatal damage to the tyre. CHINA

Accession no.716382 Item 106 Rubber World 219, No.4, Jan.1999, p.20-1 AUTOMATIC INSPECTION OF SURFACE IMPERFECTIONS AND DIMENSIONS ON ROTATIONAL SYMMETRIC MASS PRODUCTS Fuss M; Wulff P Basler Systemtechnik GmbH The technology is available now for flexible and modular automatic inspection systems which make it possible to inspect rotational symmetric mass-produced articles with high throughput for surface defects and dimensions. The handling system of the Basler 03 is able to quickly and reliably separate and convey round parts of different sizes precisely to the sensor units. The optical inspection of engineered seals includes the inspection of geometrical properties and surface defects.

JAPAN

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

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References and Abstracts

Item 107 Rubber Chemistry and Technology 71, No.3, July/Aug.1998, p.619-36 POWER TRANSMISSION BELT PERFORMANCE AND FAILURE Dalgarno K W Leeds, University A review is presented of the literature on the performance and failure of synchronous and V-ribbed belts in order to develop an overall picture of the way in which the understanding of belt materials, mechanics and failure mechanisms has progressed in recent years. 66 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.713769 Item 108 Rubber Chemistry and Technology 71, No.3, July/Aug.1998, p.590-618 TIRE BLACK SIDEWALL SURFACE DISCOLORATION AND NON-STAINING TECHNOLOGY: A REVIEW Waddell W H Exxon Chemical Co. A review is presented of the literature describing the surface discolouration problem of tyre black sidewalls and approaches to the formulation of a black sidewall compound to eliminate this surface discolouration upon exposure to ozone. Methods include use of non-staining antiozonants and use of elastomers with saturated backbones such as EPDM, halobutyl rubbers and brominated isobutylene-co-para-methylstyrene. 67 refs. USA

Accession no.713768 Item 109 Polymers & Polymer Composites 5, No.7, 1998, p.439-45 FRACTURE ANALYSIS OF DELAMINATION FAILURE IN ANGLE-PLY ELASTOMER COMPOSITES Pidaparti R M V; Kakarla V Purdue University Fracture analysis of delamination-type cracks in angleply elastomeric laminates was carried out using threedimensional finite element analysis. The fracture parameter, tearing energy/J-integral that characterised delamination failure in elastomer composites, was computed from the finite element results of stresses and strains, and compared with existing analytical results using three different methods. The results obtained were validated with existing analytical methods in the literature. Numerical results of stress distributions and J-integral values are presented for various cord orientations and crack sizes. The results obtained showed that cord orientation and crack size had a strong effect on the values

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of tearing energy/J-integral. The results of the stress distributions and J-integral should aid in understanding delamination-type failures in elastomeric composite laminates. 23 refs. USA

Accession no.713461 Item 110 Nippon Gomu Kyokaishi 70, No.12, 1997, p.715-21 Japanese FAILURE MECHANISM OF SYNCHRONOUS BELTS Iizuka H Yamagata, University The author describes a procedure involving a consideration of the type of failure, the amount of deformation, analysis of the dynamics of failure, and estimation of the service life of the belts and ways of reinforcing them. 22 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.713271 Item 111 Rubber Technology International 1998, p.75/80 NEW NON-STAINING ANTIOXIDANTS FOR DRY RUBBER APPLICATIONS Stuck B Sovereign Chemical Co. The objective of this laboratory study was to evaluate several new antioxidants versus two control antioxidants in a natural rubber/polybutadiene-based white rubber compound. The results showed several new antioxidants were developed with improved heat resistance, colour properties and economics over traditional control antioxidants. USA

Accession no.713209 Item 112 Rubber Technology International 1998, p.22-5 SILICONE RUBBER FOR ELECTRICAL INSULATORS Goudie J Dow Corning Corp. The market for composite insulators is growing steadily. Composite designs generally employ a fibreglass rod or hollow core for mechanical strength, with an outer housing made from either silicone rubber, EPDM or EPR. Insulator service life can be affected by electrical, mechanical and environmental stresses. One of the biggest

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problems in outdoor applications is airborne contamination that settles on the insulator surface. The surface of a silicone elastomer has a unique ability to interact with the contaminant and control leakage currents. 6 refs. USA

Accession no.713200 Item 113 Rubber Technology International 1998, p.18-21 CLEAN ASSEMBLIES MINIMISE HYDRAULIC SYSTEM CONTAMINATION Lough S Gates Rubber Co. Hydraulic system contamination can arise from a number of sources, including accumulation of debris that results from the hose assembly process itself. A number of methods are available to manufacturers to allow them to quantify the level of contaminants in such systems and optimise their production processes. USA

Accession no.713199 Item 114 Polimeri 17, Nos.5-6, 1996, p.258-60 Croatian FAILURE OF AUTOMOBILE TYRES Markun B Sava Semperit Failure of automobile tyres, possibilities of its determination and its consequences are analysed from different standpoints. Some ideas are suggested for increasing traffic safety. 5 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. SLOVENIA

Accession no.712027 Item 115 European Rubber Journal 180, No.11, Nov.1998, p.38/42 NEW COMPOUNDS FOR HOTTER USES Knoedgen M This article explores developments in automotive hoses, which require expensive high-performance rubbers, especially in air conditioning units and fuel systems where more aggressive fluids are being used. BAYER AG; VERITAS AG; ELF ATOCHEM; TROESTER P., MASCHINENFABRIK; ZEON EUROPE GMBH EUROPE-GENERAL; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; JAPAN; USA; WESTERN EUROPE

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Item 116 Journal of Testing & Evaluation 26, No.1, Jan.1998, p.10-4 ABILITY OF QUALITY ASSURANCE TESTS TO DETECT PUNCTURED LATEX CONDOMS WITH POTENTIAL FOR VIRUS PENETRATION Pierdominici V J B; Doucette J M; Coyne L; Cyr W H; Thomas D P; Lytle C D US, Food & Drugs Administration Defective condoms were created by puncturing with small acupuncture needles and were then tested by three quality assurance tests (the water leak test, a proposed electrical test, and the air burst) and by a virus penetration test. 13 refs. USA

Accession no.703387 Item 117 154th ACS Rubber Division Meeting - Fall 1998. Conference preprints. Nashville, Tn., 29th Sept.-2nd Oct.1998, paper 23. 012 ETHYLENE PROPYLENE POLYMER SELECTION AND COMPOUND CONSIDERATIONS FOR CHLORAMINE RESISTANCE Mitchell J M (ACS, Rubber Div.) Rubber gaskets, seals, solar tubing and membranes used in today’s water systems must resist the strong oxidising effect of water treatments. Chloramines, a combination of chlorine and ammonium hydroxide, is commonly used to control bacteria in most water systems. The concentration of chloramines and the exposure temperature may vary, but the rubber parts must resist degradation for long periods of time. In the laboratory, 60 ppm chloramines and 60 deg.C. are used to accelerate the oxidising effect on rubber parts. A volume change of less than 5% after exposure for 1000 hours is accepted in the industry for water systems. EPDM is commonly used and preferred by rubber parts manufacturers because these polymers are known to have excellent resistance to harsh environments. EPDM polymer selection along with compound considerations are important to achieve chloramine resistance. The polymer characteristics, cure systems filler selection and the effect of antioxidants are described. 5 refs. USA

Accession no.701860 Item 118 154th ACS Rubber Division Meeting - Fall 1998. Conference preprints. Nashville, Tn., 29th Sept.-2nd Oct.1998, paper 2. 012 STRAIN ENERGY RELEASE RATES FOR SOME CLASSICAL RUBBER TEST PIECES BY FINITE ELEMENT ANALYSIS

© Copyright 2002 Rapra Technology Limited

References and Abstracts

Yeoh O H Lord Corp. (ACS, Rubber Div.) Strain energy release rate or tearing energy has proved to be a valid failure criterion for a variety of rubber failure phenomena. However, apart from a small number of classical test pieces, it is difficult to calculate the tearing energy. This hampers the wider use of this criterion in failure analysis. Finite element analysis may be used to compute the tearing energy. Indeed, it has been used for this very purpose since the early 1970s. Therefore, it is perhaps surprising to find that there are basic questions relating to these classical test pieces that can be readily addressed using finite element analysis, and yet remain unanswered. Some classical rubber test pieces consisting of cracked strips and cylinders in tension are described. 11 refs. USA

Accession no.701843 Item 119 ITEC ’96 Select. Conference proceedings.. Akron, Oh., 1996, p.246-8. 6T CHANGES IN PRODUCT LIABILITY LAWS IMPACT FUTURE OF TIRE INDUSTRY Weinstein A S Weinstein Associates (Rubber & Plastics News) A detailed review of the product liability laws in the US is presented, with particular reference to the ways in which it affects tyre producers. The law imposes on the manufacturer the duty to reasonably foresee the hazards arising from all aspects of product use. Among the considerations, are hazards arising from shipping, assembly, installation, testing, instructions, warnings, intended uses, misuses, inspection, maintenance, service and disposal. A procedure for system design safety is suggested. USA

Accession no.701562 Item 120 Gummi Fasern Kunststoffe 48, No.3, March 1995, p.159-65 German INTEGRATED QUALITY CONTROL Sticher J; Ghomiem M MSG Gummiformtechnik GmbH The paper details the basic assumptions, the approach and the results of implementing ISO 9002 in a medium-sized enterprise specialising in the production of rubber products. The authors describe the experience gained during intensive work by all members of the organisation. 7 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology.

© Copyright 2002 Rapra Technology Limited

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.700430 Item 121 Nippon Gomu Kyokaishi 67, No.10, 1994, p.714-20 Japanese MECHANISMS OF TEETH SHEARING IN SYNCHRONOUS BELTS Iizuka H; Tsutsumi S; Watanabe K; Mashimo S Yamagata, University; Mitsuboshi Belting Ltd. The morphologies of tooth shearing in synchronous belts were examined after three types of fatigue tests. The belts investigated in this paper were constructed from fibrereinforced rubber composite materials. The belts consisted of rubber, fibre cords and facing fabrics. The cord was made of glass fibre and a processing compound. The teeth were made of hydrogenated nitrile-butadiene rubber (HNBR) while the facing fabric was made of nylon. Two modes of failure initiation were observed. One was cord failure initiated under various conditions, and the other mode was crack initiation which was observed under a relatively high loading on the mating flank of the belt tooth. 11 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.700397 Item 122 Nippon Gomu Kyokaishi 67, No.10, 1994, p.670-5 Japanese BREAKDOWN OF NATURAL RUBBER PRODUCTS BY MICRO-ORGANISMS Tsuchii A Shomei Industrial Technology Research Centre A brief history of research into the breakdown of natural rubber by micro-organisms is followed by a description of the nature of micro-organisms attacking rubber products, and of the stages of breakdown of the rubber products. The effect of compounding and curing conditions is discussed. 14 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.700392 Item 123 Luntai Gongye 18, No.9, 1998, p.515-9 Chinese STUDY ON DISCOLOURATION OF TYRE SURFACE Lu Shangbin

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Yinchuan China Strategy (Great Wall) Rubber Co.Ltd. It was found through the compounding test and weather test that under sunlight the black compound with antioxidant 4010NA turned red, the one with antioxidant D and BLE discoloured slightly and the one with antioxidant RD, antioxidant 4020 and wax did not discolour. The tread and sidewall compounds with antioxidant RD/antioxidant 4020/wax/microcrystalline wax showed excellent physical and ageing properties and good discolouration resistance. CHINA

Accession no.697285 Item 124 Polymer Testing ’97. Day 4: Durability of Rubber. Conference proceedings. Shawbury, 7th-11th April 1997, Paper 3. 9T ELASTOMERIC SEALING IN OFFSHORE ENVIRONMENTS Morgan G J Materials Engineering Research Laboratory Ltd. (Rapra Technology Ltd.; Plastics & Rubber Weekly; European Plastics News) Elastomers are frequently used in critical offshore situations particularly in applications that require scaling of liquids and gases. Their use as a seal material is mainly dictated by their ability to absorb wide tolerances and misalignments in metalwork and still maintain sealability better than other materials such as thermoplastics and metal itself. The means of examining the properties of an elastomer relevant to its functioning as a seal are described, together with methods developed in a recent joint industry project for assessing the lifetime of a seal in service in potentially hostile environments such as occur offshore. 2 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.694720 Item 125 NRC 98 - Nordic Rubber Conference 1998. Conference proceedings. Halmstad, Sweden, 4th-5th June 1998, paper 10. 012 USE OF ELASTOMERIC SEALS OFFSHORE Olsen A Norsk Hydro Research Center (Sveriges Gummitekniska Forening; NGTR) This paper concerns the use of elastomeric seals offshore. General properties and fluid compatibility for five most common elastomeric types used in oil and gas are described. These are NBR, HNBR, fluorocarbon elastomers, perfluoroelastomers and tetrafluoroethylenepropylene. SCANDINAVIA; SWEDEN; WESTERN EUROPE

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Item 126 Rubber Asia 12, No.4, July/Aug.1998, p.131-5 WHY LIFE PREDICTION OF ELASTOMERS IS IMPORTANT Pannikottu A Akron Rubber Development Laboratory Inc. Service life prediction is of both practical and scientific interest. The service life of an elastomer sets a limit to engineering design. Therefore, life prediction of elastomers should be part of the engineering design process. Elastomer properties are sensitive to heat, moisture, light, fluids and mechanical stress. Elastomers can undergo changes in properties large enough to cause product failure. Most elastomeric parts in engineering applications are intended to be in service for several years. Hence, the engineer or the developing scientist cannot wait that long to evaluate the ageing process in actual service conditions. The three major engineering tasks in elastomer applications are to determine the shelf life, service life and remaining useful life (part already in use). A practical usable methods for quantitative life prediction of elastomers is outlined. USA

Accession no.690164 Item 127 Tire Technology International 1998, p.286-90 TYRE SIDEWALL INSPECTION Harris M Bytewise Measurement Systems Effective final inspection prior to delivery to customers is a key element of a successful operation. This comprehensive article supplies details of the operation, advantages and features of a sidewall monitoring system from Bytewise Measurement Systems of the USA. Applying laser triangulation to sidewall measurement has resulted in a system that offers high accuracy, simple operation and easy integration into existing inspection systems. The company also claim major savings from the use of the system, with some plants finding their savings to be over one million US dollars annually. USA

Accession no.685107 Item 128 153rd ACS Rubber Division Meeting - Spring 1998. Conference preprints. Indianapolis, In., 5th-8th May, 1998. Paper 23. 012 MICROSCOPIC IMAGE ANALYSIS OF ELASTOMERS CAN INFER PHYSICAL PROPERTIES DiFoggio R; McElrath K O; Tisler A L; Ball J W Exxon Chemical Co. (ACS, Rubber Div.)

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References and Abstracts

Immiscible elastomers are often blended together. The ways in which the elastomer ingredients are mixed together and how they are cured make a big difference in the resulting morphologies of the microscopic elastomer domains, even if one starts out with the same set of ingredients. Distinct micron-sized elastomer domains can be observed for such blends by using transmission electron microscopy or atomic force microscopy. By applying image analysis techniques, the number, shapes and areas of these domains can be quantified. Good correlations are found between these quantitative image parameters and physical properties such as Shore A, adhesion, DeMattia crack length and fatigue to failure. These correlations demonstrate the importance of microscopic morphology to the performance of elastomer blends. 5 refs. USA

Accession no.683241 Item 129 Adhesives Age 41, No.5, May 1998, p.44/8 RILEM DISCUSSES DURABILITY Wolf A Dow Corning Corp. Synopses are presented of papers given at the RILEM Symposium on the Durability of Building Sealants. Topics covered include the long term stability of elastomeric building sealants; case studies on the inspection and resealing of failed joint systems; the prediction of service lives of joint sealants; comparative evaluation of silicone sealants under various accelerated weathering regimes; the effects of joint geometry on the engineering properties of elastomeric structural sealants and adhesives; and the further development of a universal test standard for sealant durability and in-service strength. USA

Accession no.682508 Item 130 Rubber World 217, No.5, Feb.1998, p.41-5 ELASTOMER BLEND APPROACH TO EXTEND HEAT LIFE OF NATURAL RUBBER BASED ENGINE MOUNTS Measmer M B; McElrath K O Exxon Chemical Co. Natural rubber has been used for many years in engine mounts, but there have been some failures in recent years as the underhood temperatures of certain car models have risen. Previous work has shown that brominated isobutylene-p-methylstyrene rubber, when blended at concentrations of 20-30phr with NR, result in compounds with favourably low spring rates and significantly improved hot air ageing performance. This article presents some dynamic property data for rubber compounds of

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varying compositions and the change in these properties as the compounds are subjected to hot air ageing. 2 refs. USA

Accession no.677100 Item 131 Rubber and Plastics News 27, No.11, 12th Jan.1998, p.14-5 INTRINSIC DEFECT EFFECTS ON NR PERMEABILITY Roland C M; Choi I S; Schroeder M J US, Naval Research Laboratory; US, Naval Academy Recent evidence of the ability of viral-sized particles to pass through ostensibly intact latex rubber films calls into question the ability of latex rubber gloves and condoms to function effectively as prophylactics. The origin of this permeability is presently unknown. This comprehensive article examines the size of the intrinsic flaws in natural rubber of varying grades and in guayule rubber. Experiments measuring the permeation of micron- and submicron-size particles through latex rubber films are also described. 21 refs. USA

Accession no.672799 Item 132 Rubber and Plastics News 27, No.3, 8th Sept.1997, p.6 OSHA CITES DARTMOUTH COLLEGE IN GLOVE DEATH Campanelli J It is reported that in the USA, the Occupational Safety & Health Administration has cited Dartmouth College for failing to warn its laboratory researchers about the limitations of latex gloves and for other safety violations. This follows the tragic death of Professor Karen Wetterhahn, who died after spilling dimethyl mercury on her gloves at the college. US, OCCUPATIONAL SAFETY & HEALTH ADMINISTRATION; DARTMOUTH COLLEGE USA

Accession no.665006 Item 133 Revue Generale des Caoutchoucs et Plastiques No.743, Sept.1995, p.74-6 French STUDY OF THE THERMAL AGEING OF CHLOROSULPHONATED POLYETHYLENE Audouin L; Gueguen V; Verdu J; Pinel B ENSAM; EDF/DER Samples of chlorosulphonated PE were thermally aged in ventilated ovens at temperatures between 70 and 135C. The ageing process was studied by tensile tests, equilibrium swelling measurements and gravimetric analysis of the loss

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References and Abstracts

of volatile substances. The results revealed the existence of three different processes, i.e. loss of plasticisers and other volatile substances, crosslinking and dehydrochlorination after consumption of stabilisers. 6 refs. DU PONT DE NEMOURS E.I., & CO.INC. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; USA; WESTERN EUROPE

Accession no.663451 Item 134 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 65, pp.19. 012 IMPROVEMENT OF TIRE SIDEWALL APPEARANCE USING HIGHLY SATURATED POLYMERS: ORIGIN OF SIDEWALL CRACKING Mouri H; Tonosaki Y Bridgestone Corp. (ACS, Rubber Div.) A study was made of the fatigue life of black tyre sidewall compounds based on NR/polybutadiene blends with highly saturated polymers, i.e. EPDM or a brominated isobutyleneparamethylstyrene copolymer. The major factor responsible for fatigue failure was found to be the size of flaws in the specimens caused by poor polymer dispersion, resulting from incompatibility or poor mixing quality associated with highly saturated polymers. The size of initial flaws deduced from fatigue to failure testing was in line with the polymer dispersion ranking. It was concluded that crack growth in sidewalls containing highly saturated polymers is driven primarily by the size of intrinsic defects, rather than by the crack growth rate of the polymer. 9 refs.

Item 136 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 59, pp.11. 012 SCIENCE OF MIXING OF RUBBER: MATERIAL PROBLEMS Yamaguchi Y Yokohama Rubber Co.Ltd. (ACS, Rubber Div.) Some problems associated with rubber mixing are examined, including scorching due to stagnation, edge roughness of sheeted rubber and inhomogeneous dispersion of carbon black. These phenomena are discussed in relation to the deformation behaviour, fracture characteristics and rheological properties of compounds. 6 refs. JAPAN; USA

Accession no.659509 Item 137 Rubber World 216, No.6, Sept.1997, p.31/77 EFFECT OF FLAWS ON FATIGUE LIFE IN BUSHINGS Sommer J G Elastech Inc.

JAPAN; USA

Silentbloc bushings have a long history of successful use in automotive suspension systems where good fatigue life is essential. Earlier work has shown that the addition of 0.5pphr of sand halved the fatigue life of an NR vulcanisate. This study extends this earlier work by examining a range of silica particle diameters at the 0.5pphr level on fatigue life in NR bushings. 5 refs.

Accession no.659514

USA

Item 135 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 62, pp.55. 012 TIRE BLACK SIDEWALL SURFACE DISCOLORATION: A REVIEW Waddell W H Exxon Chemical Co. (ACS, Rubber Div.) A review is made of the literature describing the surface discolouration of black tyre sidewalls caused by exposure to ozone and formulation studies undertaken to overcome this problem. Methods examined include the use of nonstaining antiozonants and blending inherently ozone resistant rubbers such as EPDM, halobutyl rubbers and brominated isobutylene-paramethylstyrene copolymers with NR and/or polybutadiene. 67 refs. USA

Accession no.659512

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Accession no.659297 Item 138 IRC ’97. Conference proceedings. Kuala Lumpur, 6th-9th Oct.1997, p.370-5. 012 BENEFITS VERSUS RISK OF USING NATURAL RUBBER LATEX GLOVES Lai Pin Fah Rubber Research Institute of Malaysia (Rubber Research Institute of Malaysia) The most important reason why personnel in the healthcare industry wears gloves is to prevent transmission of micro-organisms to and from the patient. With the onset of HIV and the fear among healthcare providers about cross contamination (patient-tohealthcare provider), the use of gloves, particularly NR latex gloves, has proliferated. The lives of a great many doctors and nurses have been saved because of this. However, in recent years, the major preoccupation of the western mass media covering glove usage has been on the negative aspects of NR latex gloves. They have been

© Copyright 2002 Rapra Technology Limited

References and Abstracts

portrayed as causing more harm than good to users. There is hardly any discernible coverage of the immense benefits of these gloves. The many articles written in journals, magazines and the Internet centre almost entirely on the latex allergy problem and the risks associated with it. A balanced view of the allergy problem and the advantageous characteristics of latex gloves are presented. 21 refs.

special-construction Poly Chain GTO belt. The Poly Chain belt is made of a highly compounded PU material and has more than twice the horsepower capacity of a rubber belt. Aspects covered include field observations, failed belt analysis, engineering analysis, laboratory tests, general findings and changes resulting from the test programme. USA

Accession no.657636

MALAYSIA

Accession no.658905 Item 139 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 34, pp.16. 012 APPLICATION OF FRACTURE MECHANICS TO FAILURE IN RUBBER-CORD LAMINATES Lake G J East London, University (ACS, Rubber Div.) The use of a fracture mechanics approach based on the strain energy release rate to assess failure in rubber-cord laminated structures is reviewed. The mechanics of crack propagation are considered for cracking either between the plies or around individual cords, and also for crack initiation and growth near cord ends. The ability of the approach to predict the effects of various design and construction parameters on laminate failure is also discussed. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.658288 Item 140 Rubber Technology International 1997, p.28-34 SUPERCHARGER BELT FAILURES - STUDY Shepherd J Gates Rubber Co. Gates Rubber has devoted considerable engineering resources to understanding and solving the problem of broken supercharger drive belts on racing engines in the Top Fuel and Funny car classes. Since the late 1950s, supercharger drive belts have been used on various dragracing cars - many of the first units were driven directly off the front of the engine. A typical run for a dragster at that time was 8.5 seconds at 150mph, compared to today’s records that exceed 300mph and fall well into the foursecond range. Modem blowers are on top of the engine and driven by a rubber timing belt. The size of the blower has at least doubled from earlier models and blower speed now is as much as 1.6 times the engine rpm. Belts for topmounted blowers have changed from a 1.5in-wide H (0.5in pitch) Gilmer belt to a 2in rubber HTD belt, and more recently to a 75mm-wide, 14mm-pitch HTDO profile

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Item 141 Rubber Technology International 1997, p.25-7 ACHIEVING SEAL OF APPROVAL Hickson J S St.Clair (Polymers) Ltd. Seals themselves are relatively small and cheap but some of the wide range of applications they are found in are highly critical. Seal failure can involve very high costs, and even loss of life. Failure can be catastrophic, when a seal condition steadily weakens the seal until failure suddenly occurs, or more usually by a slowly increasing rate of leakage up to a specified maximum used to define failure. Preventative maintenance can avoid the latter type of failure. The effect of failure should be considered at an early stage in the design or selection of the seal type to be used - this is also a good time to consider the problem of installation of the seal in the first place. A simple example of a propeller shaft seal on a large ship illustrates the cost of failure. When leakage becomes unacceptable the ship is out of commission until dry-docked and a replacement fitted. The total costs can thus be extremely high. The essential properties of rubber that are important in sealing are low modulus, elasticity, low compressibility, high coefficient of friction, high strength and fluid resistance. Some emphasis is replaced on the material requirements of O-rings. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.657635 Item 142 Luntai Gongye 17, No.8, 1997, p.500-2 Chinese CAUSES OF BLISTERS ON INNER SIDE OF TRUCK TYRE AND THEIR PRECAUTIONS Chongcai Y 1 ref. CHINA

Accession no.651042 Item 143 NRC ’96. Conference proceedings. Helsinki, 23rd-24th May, 1996, paper 6. 8 CHARACTERISATION OF NATURAL RUBBER LITERATURE SURVEY AND EXPERIMENTAL STUDY

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Asplund J; Bengtsson A; Stenberg B Trelleborg Industri AB; KTH (Finnish Association for Rubber Technology; Nordic Council of Rubber Technology) Many sources can cause chemical or structural variations in NR. To obtain NR with constant mechanical properties, it is very important to keep all factors uniform during raw rubber production. To ensure as little variations as possible of the rubber, the specification for NR grades should prescribe how a certain grade is to be produced. A literature survey and experimental study are presented. A number of chemical, structural and mechanical properties of nine samples of three different natural rubber materials are analysed. The characterisation includes chemiluminescence, acetone extraction, gel content, gel permeation chromatography, pyrolysis-gas chromatography, IR spectroscopy, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and rheology. Large variations are found in concentration of hydrogen peroxide, gel content, amount and composition of acetone-extractable material, average molecular weight and molecular weight distribution. SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.641385 Item 144 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 97, pp.39. 012 QUALITY ASSURANCE OF NATURAL RUBBER USING THE RUBBER PROCESS ANALYZER Dick J S; Harmon C; Vare A Alpha Technologies; Cooper Tire & Rubber Co.; Michelin North America (ACS, Rubber Div.) Results are presented of high strain testing for the characterisation and quality assurance of NR using the RPA 2000 rubber process analyser. Such testing was found to be more effective in detecting processability differences than traditional processing tests such as Mooney viscosity or Wallace plasticity. 24 refs. USA

Accession no.639074 Item 145 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 96, pp.27. 012 INTRINSIC FLAWS IN NATURAL RUBBER Roland C M; Choi I S US, Naval Research Laboratory (ACS, Rubber Div.) A comparison was made of the room temperature strain crystallisation of naturally occurring cis-1, 4polyisoprenes with varying non-rubber contents, i.e. NR

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grades of different purity, a deproteinised NR and a guayule rubber. Crystallisation was assessed by stress relaxation and optical birefringence measurements and IR spectroscopy. The results showed that the strain required to induce crystallisation was less for polymers having larger concentrations of impurities. Thus guayule rubber crystallised at lower strains than NR, and deproteinised NR required the highest strain to induce crystallisation. The propensity for strain crystallisation correlated with the relative failure properties of the rubbers. 62 refs. USA

Accession no.639073 Item 146 151st ACS Rubber Division Meeting, Spring 1997, Conference Preprints. Anaheim, Ca., 6th-9th May 1997, Paper 30, pp.15. 012 ELASTOMER BLEND APPROACH TO EXTEND HEAT LIFE OF NATURAL RUBBER BASED ENGINE MOUNTS Measmer M B; McElrath K O Exxon Chemical Co. (ACS, Rubber Div.) The heat ageing resistance of NR compounds for automotive engine mounting applications was improved by blending with a brominated isobutylene-pmethylstyrene copolymer (BIMS). The effects of BIMS microstructure and antidegradants on heat ageing resistance were examined. The compounds showed excellent stability of dynamic properties (less than 10% change) up to 210 hours’ ageing at 125C. Optimum resistance to ozone cracking was obtained for blends containing 30 phr of BIMS. 2 refs. USA

Accession no.636040 Item 147 Kautchuk und Gummi Kunststoffe 50, No.4, April 1997, p.299-303 MECHANICAL PROPERTIES OF ELASTOMER COMPOUNDS IN SYNCHRONOUS AND VRIBBED BELTS Dalgarno K W; Childs T H C; Day A J; Hojjati M H; Moore R B; Yu D Q Leeds, University; Bradford, University Work carried out to identify how the performance of power transmission belts may be improved is described. An examination is made of which mechanical properties of the elastomer compound are of significance in determining belt performance, and to identify how the significant elastomer compound properties may be changed to improve belt performance. This work encompasses the examination of belt failure and modelling of belt operation to ensure that the current limits of belt performance are fully understood. It is concluded

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References and Abstracts

that such an approach can be of value in improving belt performance. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.635691 Item 148 Journal of Applied Polymer Science 64, No.3, 18th April 1997, p.553-66 PERMEABILITY AND MATERIAL CHARACTERISTICS OF VULCANIZED LATEX FILM DURING AND FOLLOWING CYCLIC FATIGUE IN A SALINE ENVIRONMENT Dillon J G; Schroeder L W US, Food & Drug Administration A test apparatus was constructed which allowed the monitoring of ion permeability and electrical properties of vulcanised latex glove material during cyclic fatigue in a saline environment. The results obtained showed that glove latex failure, under these test conditions, began nearly 10 min before catastrophic rupture. Sodium ion permeation did not occur until the time of rupture, indicating that true pores existed only at the time of catastrophic failure. SEM of the fatigued membrane showed stress and rupture of the fibril network surrounding the individual latex particles. The fatigue lifetime of the latex glove material was found to be about 2 h under stress similar to actual use. 32 refs. USA

Accession no.632487 Item 149 Luntai Gongye 17, No.2, 1997, p.119-20 Chinese INVESTIGATION ON COMMON ABNORMAL FAILURES OF TYRE Guangxiang P; Xianjie G

STUDY ON IMPROVING PERFORMANCE OF NYLON TRUCK TYRE AT HIGH SPEED Shenyan L; Xirong L; Shiyan Y; Honghua L; Bo G; Liying M; Yan Z Beijing, Institute of Rubber Research & Design The causes of nylon truck tyre to fail on the highway were analysed. The several technical measures for improving the performance of the tyre at high speed were taken to make the overall performance of an 11.00-20 16PR test tyre in accordance with the targets set in the project for tackling key problems. The endurance tests showed that the maximum bench life of the test tyre at a standard test speed of 65km/h reached 158.72h; the tyre passed the test at the speed of 110km/h for 2h. 12 refs. CHINA

Accession no.631904 Item 152 Journal of Biomedical Materials Research 34, No.3, 5th March 1997, p.371-9 POLYURETHANE HEART VALVES: FATIGUE FAILURE, CALCIFICATION AND POLYURETHANE STRUCTURE Bernacca G M; Mackay T G; Wilkinson R; Wheatley D J Glasgow, Royal Infirmary; Strathclyde, University Long-term fatigue and calcification testing was conducted on six flexible-leaflet prosthetic heart valves fabricated from a polyether-urethane-urea. Three valves exceeded 800 million cycles without failure, while three valves failed at 775, 460 and 544 million cycles, respectively. Calcification was observed with and without associated failure in regions of high strain. Comparison was made with valves prepared from polyether-urethane. The results indicated that PU valves could achieve the durabilities required of an implantable prosthetic valve, equalling the fatigue life of currently-available bioprosthetic valves. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.631089

CHINA

Accession no.631924 Item 150 Luntai Gongye 17, No.1, 1997, p.56-7 Chinese CHARACTERISTICS AND CAUSE OF TYRE FAILURE Yanquan Z CHINA

Accession no.631911 Item 151 Luntai Gongye 17, No.1, 1997, p.3-12 Chinese

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Item 153 Journal of Biomedical Materials Research 34, No.4, 15th March 1997, p.519-30 ROLE OF OXYGEN IN BIODEGRADATION OF POLY(ETHERURETHANE UREA) ELASTOMERS Schubert M A; Wiggins M J; Anderson J M; Hiltner A Case Western Reserve University This work demonstrates that PEUU degradation is a surface phenomenon resulting from a classical autooxidation mechanism. By modelling the depth of the surface degraded layer with a diffusion-reaction model, it was shown that PEUU degradation was controlled by diffusion of oxygen into the polymer. 25 refs. USA

Accession no.629085

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References and Abstracts

Item 154 Industria della Gomma 39, No.10, Oct.1995, p.16-20 Italian ELECTROCHEMICAL DEGRADATION OF EPDM COOLER HOSES Vroomen G; Verhoef H DSM Elastomers Europe; DSM Research BV Results are presented of studies by DSM of the mechanism of electrochemical degradation of EPDM automotive cooler hoses in contact with water/ethylene glycol coolants, and of the cracking occurring after different exposure times. The resistance to electrochemical corrosion was influenced by the composition of the EPDM compounds. Vulcanisates in which electrical conductivity was reduced by partly replacing carbon black with calcium carbonate were resistant for longer periods than vulcanisates filled with carbon black alone. The degree of crosslinking and type of curing agent used also influenced the resistance of the vulcanisates to degradation. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.621093 Item 155 China Synthetic Rubber Industry 19, No.6, 1996, p.325-30 Chinese DEVELOPMENT OF RESEARCH ON TANK TRACK RUBBER PADS Liquin Z; Haiping G; Song C; Xiaobing M; Xiaodong S Beijing, University of Chemical Technology; Beijing, Research & Design Inst.of Rubber Ind.; China, National Defence Science Technology & Industry Committee

developed in the cord was measured and its relevance to the pattern of failure was investigated. 11 refs. Translation of Nippon Gomu Kyokaishi, No.8, 1995, p.559 JAPAN

Accession no.614560 Item 157 Modern Tire Dealer 77, No.11, Oct.1996, p.45/8 SPEED KILLS TRUCK TIRE EFFECTIVENESS Wagner E J Tire Technical Services Inc. This article, from the president of Tire Technical Services Inc. of the USA, investigates the reducing of effectiveness of lorry tyres by increased speed. The following are all covered: speed limits, tyre loads, tyre revolutions, tyre temperature, fatigue, centrifugal force, fuel efficiency and tyre wear. USA

Accession no.612210 Item 158 150th ACS Rubber Division Meeting. Fall 1996. Conference Preprints. Louisville, Ky., 8th-11th Oct.1996, Paper 66, pp.75. 012 STRESSES, SLIP AND ABRASION OF RUBBER COVERED CONVEYOR ROLLERS: A REVIEW Metlikovic P; Meinecke E A Sava Rubber Industry; Akron, University, Institute of Polym.Science (ACS, Rubber Div.)

The mechanisms and model of damage of tank track rubber pads and the development of research of these pads from rubber compound and property tests are reviewed. Some proposals for the development of these pads are presented. 37 refs.

Aspects of pressure, shear stress, friction and abrasion in rubber covered conveyor rollers are reviewed. A model is presented for predicting the effect of belt pressure on the deformation of the lagging, and equations are developed for predicting stresses, slip and abrasion. Experimental results are compared with theoretical predictions. Guidelines are given for the design of rollers with longer service life. 111 refs.

CHINA

SLOVENIA; USA

Accession no.616985

Accession no.611824

Item 156 International Polymer Science and Technology 23, No.7, 1996, p.T/75-80 FATIGUE FAILURE OF TIMING BELT CORD Iizuka H; Mashimo S; Osako N

Item 159 Journal of Biomaterials Applications 11, No.2, Oct.1996, p.121-34 RESISTANCE TO BIODEGRADATIVE STRESS CRACKING IN MICROPOROUS VASCULAR ACCESS GRAFTS Carson R J; Edwards A; Szycher M CardioTech International

To elucidate the mechanism of failure in timing belts, measurements of the displacement in the cord and its vicinity were made and fatigue tests were carried out on the cord. The timing belt was of the rounded tooth STPD type. The study investigated which of the components of cyclic deformation belt interior in the belt interior initiate and promote cord failure. In particular, the curvature

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The in-vitro test developed for comparative evaluation of microporous vascular grafts provided an aggressive oxidising environment which was known to cause degradation of a polyether-urethane, similar to that

© Copyright 2002 Rapra Technology Limited

References and Abstracts

observed in an in-vivo situation. The systems showed an acceleration factor of about 9 times over in-vivo trials (for the Estane 5714 F1 polyether-urethane material) with catastrophic failure occurring in week 6 of the in-vitro test and in week 52 during in-vivo trials. The new generation polycarbonate-based PU, ChronoFlex, however, displayed outstanding resistance against environmental stress cracking, maintaining its structure throughout the test period of 35 weeks. 23 refs.

In the majority of elastomeric components, failure is not usually due to a large static load resulting in catastrophic failure, but to much smaller cyclic fatigue loads. Hence, it is this latter mode of failure that should be used as the criteria when designing a component. This can be achieved by applying a fracture mechanics approach and determining the level of tearing energies generated in the component due to the fatigue loads, and then this in turn can be related to a crack growth rate for the relevant elastomer.

USA

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.610683 Item 160 IRC ’96. International Rubber Conference. Conference proceedings. Manchester, 17th-21st June 1996, paper 8. 012 ASPECTS OF FAILURE IN RUBBER COMPONENTS Busfield J J C; Davies C K L; Thomas A G London, University; Queen Mary & Westfield College (Institute of Materials) A methodology to predict failure of rubber components under repeated stressing is discussed. A fracture mechanics approach is adopted, which has been shown to work with simple plane stress geometries. The use of finite element techniques allows the solution of fracture problems for more complex three-dimensional geometries at large deformations. At large strains the material behaves in a very non-linear manner and this requires the use of suitable stored energy functions, to give a realistic approximation of the behaviour. The crack growth behaviour of a penny shaped flaw caused by hydrostatic tensile stresses is particularly described. This type of failure is common in some bonded components, due to the stresses induced by thermal contraction from the moulding temperatures. This phenomenon is similar to that of explosive decompression, observed in off-shore industrial applications, when rubber seals are raised from the sea bed, and the internal pressure is dramatically reduced. Comparison is made with a small strain solution and agreement is excellent. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.610024 Item 161 IRC ’96. International Rubber Conference. Conference proceedings. Manchester, 17th-21st June 1996, paper 5. 012 FATIGUE LIFE PREDICTIONS FOR ELASTOMERIC COMPONENTS Hawkes J; Harris J; Stevenson A; Samulak M; Hansen P; Becker E; Miller T; McMullen R Materials Engineering Research Laboratory; Mechanics Software Inc. (Institute of Materials)

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Accession no.610021 Item 162 International Polymer Science and Technology 23, No.5, 1996, p.T/39-40 CALCULATION AND PREDICTION OF FATIGUE CHARACTERISTICS OF VULCANISATES AND RUBBER-CORD COMPOSITES Zhbakov B I A report is presented on the derivation of a relationship between log N (where N is the number of cycles to fatigue failure) and log alpha (where alpha is the mechanical fatigue parameter) for vulcanisates and rubber-cord composites under cyclic fatigue conditions. It is shown that, based on new theories and on the proposed equation, a simple method can be developed which ensures more objective and accurate calculation and prediction of the fatigue characteristics of vulcanisates and rubber-cord composites from the fatigue strength indices in the region of low-cycle fatigue. This approach is said to reduce labour costs and the time spent on preliminary tests by several orders of magnitude. 5 refs. (Full translation of Kauch.i Rezina, No.5, 1995, p.31) CIS; COMMONWEALTH OF INDEPENDENT STATES

Accession no.608095 Item 163 Rubber World 214, No.5, Aug.1996, p.15/84 PHYSICAL PROPERTIES AND THEIR MEANING Sommer J G Elastech Inc. This article, the third instalment of a seven-part series, examines vulcanised properties of rubber, including hardness, stress-strain properties and uniaxial tension. Tensile testing merits considerable attention because it is done so extensively in the rubber industry. Results from tensile tests are sensitive to manufacturing errors such as state of cure, dispersion of ingredients and presence of foreign material, and these limitations should be recognised. Tensile properties of rubber demonstrate little if any relation to serviceability of most rubber products. 26 refs. USA

Accession no.606709

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References and Abstracts

Item 164 Materials World 4, No.5, May 1996, p.255-8 CONDOMS IN THE AGE OF AIDS Hill D M; Larque S J; Lyszkowski A D L; Porter M; Potter W D; Solanki S L; White N D; Williams T H London International Group The history of the development of condoms precedes a review of the use of natural latex rubber condoms, with details of some of the problems encountered by users, and the subsequent development of a polyurethane condom by London International Group. The use of condoms for both pregnancy prevention and as a barrier to sexually transmitted diseases, including AIDS, is discussed, and the effectiveness of both latex and PU for this purpose. The use of polyurethane condoms as an alternative to latex by those experiencing latex sensitivity, either due to the protein in the rubber or vulcanising agents is proposed, since polyurethane has been shown to be nonallergenic. Test methods for condoms are examined, and results of in-use studies of the Avanti condom made from Duron brand PU are discussed. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.592380 Item 165 Contraception 53, No.3, 1996, p.155-8 DOES ADDITIONAL LUBRICATION REDUCE CONDOM FAILURE? Gabbay M; Gibbs A Manchester, University A report is presented on a questionnaire-based study which investigated the use of additional lubrication with condoms amongst 525 female students presenting for post-coital contraception and the current and past experience of condom and additional lubrication use amongst 481 controls attending the same health centre. Of those requesting post-coital contraception, 83% claimed condom failure as the cause, with 66% of the control group having also experienced condom failure at some time. The use of additional water-based lubrication was significantly associated with lower condom failure rates. Gender, regularity of use of condoms and use of oil-based lubricants were not associated with higher failure rates. Additional lubricant use was not significantly associated with increased condom slippage. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.591327 Item 166 International Journal of Adhesion & Adhesives 16, No.2, May 1996, p.105-7 ESSENTIAL ROLE PLAYED BY ADHESION IN

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THE TECHNOLOGY OF NEUROLOGICAL PROSTHESES Donaldson P E K Early implanted microelectronic devices for neurological prostheses, including the cardiac pacemaker, suffered premature encapsulation failures, probably because the function of the encapsulant had received insufficient thought. Subsequent research, conducted at the Medical Research Council, showed that the important property required of an encapsulant was not impermeability, as had been assumed, but adhesion. It was shown that bonds could be made between rubber and alumina or between rubber and titanium which could withstand boiling at pHs between 4 and 10 for at least 200 days. This was thought to correspond to a life of about 50 years, at 37C, in a patient. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.591304 Item 167 Contraception 53, No.4, 1996, p.221-9 LATEX RUBBER CONDOMS: PREDICTING AND EXTENDING SHELF LIFE Free M J; Srisamang V; Vail J; Mercer D; Kotz R; Marlowe D E US, Program for Appropriate Technol.in Health; US, Food & Drug Administration Condoms from five manufacturers were subjected to controlled exposures of heat, humidity and air and to different natural environments in five countries. Under aerobic conditions (condoms in permeable packages or unpackaged), stress properties declined. The relationship between rate of decline as a function of temperature was quadratic. Under oxygen-restricted conditions (foilwrapped packages) at average storage temperatures of 30C and lower, strain properties declined with little or no significant change in stress properties. The effect is to cause condoms to become stiffer; high-breakage rates in use have been correlated with product stiffening. A new rationale for accelerated ageing tests to predict condom shelf stability is suggested, including a test to control the trend of condoms to stiffen. Silicone lubricant, impermeable packaging and inclusion of antioxidants in the condom formulations can prevent or minimise aerobic breakdown of latex condoms. Specifying low-modulus condoms can prevent excessive stiffening. 5 refs. USA

Accession no.590542 Item 168 International Polymer Science and Technology 22, No.12, 1995, p.T/47-57 DEGRADATION MECHANISMS OF RUBBERS Saito Y

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References and Abstracts

A review of the literature on degradation mechanisms of rubbers is presented, covering thermooxidative degradation, thermal decomposition, radiation degradation, UV radiation degradation (weather resistance) and ozone degradation. 66 refs. (Full translation of Nippon Gomu Kyokaishi, No.5, 1995, p.284) JAPAN

Accession no.590011 Item 169 International Polymer Science and Technology 22, No.11, 1995, p.T/24-8 INFLUENCE OF DESIGN FACTORS ON THE FAILURE RESISTANCE OF VULCANISATES IN PRODUCTS Zuev Y S; Kaporovskii V M; Yurtsev N N Design optimisation factors to be borne in mind when designing multi-component products containing rubber in conjunction with metals, fabrics, cord or plastics, are considered in order to increase the failure resistance of rubbers. Two groups of factors are considered: the first involves rubbers as part of a design which includes considerations such as limitation of deformation of the rubber as a result of its being joined to rigid material by bonding; direct vulcanisation, or contact with fittings; and the scale factor in which changes in the size of the rubber part of the product are taken into account. Secondly, rubbers as materials, in which consideration is given to reduction or elimination of tensile stresses, the increase in amount of dispersed energy as proportion of total amount of energy produced by rubber during deformation; reduction in influence of changes in temperature; and increase in resistance to corrosive media. 27 refs. Translation of Kauchuk i Rezina, No.3, 1995, p.5. RUSSIA

Accession no.588415 Item 170 Indian Rubber Journal Vol.17, Jan-Feb.1996, p.74-6 RUBBER AND RUBBER PRODUCTS: NEED FOR QUALITY IMPROVEMENTS Thomas K K; Matthew N M; Thomas E V A review is presented of discussions which took place at the International Seminar on ISO 9000 for Rubber and Rubber Products held at Ooty, India, December 1995. Discussed are the four primary uses for ISO 9000 as a guidance for quality management, contractual agreement, second party approval or registration and third party certification or registration, and the use of quality records to provide evidence to demonstrate conformity. Details are given of the number of rubber companies in Malaysia, Indonesia, Thailand, Sri Lanka and India who have obtained certification. ASIA; INDIA

Accession no.587055

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Item 171 Rubber Chemistry and Technology 68, No.5, Nov-Dec.1995, p.804-14 CORRELATION BETWEEN LABORATORY AND ROAD RUBBER WEAR TESTS Krishnan V; Ramakrishnan R; Donovan J A Massachusetts, University The wear resistance ranking of three rubber compounds (SBR(40% styrene/SBR(23% styrene), SBR(23% styrene)/cis-polybutadiene and NR/SBR(15% styrene)/ SBR(33% styrene) measured in the laboratory at medium to high slip on sharp silicon carbide grinding wheels was similar to that determined by road tests at Pecos, Texas. The wear resistance ranking of the three compounds changed on blunt alumina grinding wheels compared with rankings on sharp SiC grinding wheels. The change was probably due to a change of mechanism from mainly cutting on sharp surfaces to predominantly fatigue on blunt surfaces. For these three compounds, a change in the ambient temp. from 23 to 75C during laboratory testing had no effect on the wear resistance ranking. The wear of the rubber compounds on the abrasive grinding wheels and during road tests followed Zapp’s relation in which the wear was proportional to the ratio of dynamic modulus to rupture energy. 15 refs. (ACS Rubber Div., Spring Meeting, Philadelphia, May 1995) USA

Accession no.586557 Item 172 IRC ’95 Kobe International Rubber Conference. Conference proceedings. Kobe, 23rd-27th Oct.1995, p.160-3. 012 FATIGUE FAILURE OF SYNCHRONOUS BELTS Izuka H; Tsutsumi S; Watanabe K; Mashimo S; Ohsako N Yamagata, University; Mitsuboshi Belting Ltd. (Japan, Society of Rubber Industry) Fatigue failure mechanism of synchronous belting is investigated. Firstly, damage morphology is observed by the following fatigue tests. The fatigue initiation site is at the centre of belt cord. The failure is then propagated into the outer rubber layer. The cord is damaged mainly by the bending fatigue. The curvature of the cord is therefore measured when the belt is bent around the pulley, and the effects of belt tension and radius of pulley on the curvature are discussed. 5 refs. JAPAN

Accession no.586145 Item 173 Euradh ’94. Conference Proceedings. Mulhouse, 12th-15th Sept.1994, p.482-5. 9(12)4 ADHESION OF HIGHLY FILLED POLYURETHANE NETWORKS Bessaha N; Vallat M F; Schultz J; Combette C; Maucourt J

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References and Abstracts

Centre de Recherches sur Physico-Chimie Surf.Sol.; Societe Nationale des Poudres et Explosifs (Societe Francaise du Vide; Institute of Materials; Dechema Institut) Adhesion between the propellant and the case in solid rocket fuel propellants was studied. The adhesion mechanisms between an inert propellant (a highly filled PU, based on hydroxy-terminated polybutadiene prepolymer, diisocyanate and inert loadings) and a liner of the same nature of prepolymer, diisocyanate, chain extenders and carbon black were investigated. The interfacial properties were found to be influenced by the properties of the prepolymer used. The adhesion of the assembly was only slightly affected by the state of cure of the liner before propellant coating. In peel tests, cohesive failure occurred in the propellant near the interface, IR spectrometry of the propellant surface after separation showed the formation of an interphase in the propellant, dependant on the prepolymer. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.584903 Item 174 Trends in Polymer Science 4, No.2, Feb.1996, p.36-7 SILICONE IMPLANTS: QUESTIONS AND STILL MORE QUESTIONS Hawthorne W Elsevier Trends Journals The current situation with regard to silicone breast implants is discussed, with reference to claims that women have suffered physical injury from deterioration of, or leakage from, the devices. Legal and scientific questions and causal questions are briefly considered. 1 ref. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.582507 Item 175 Biomaterials 17, No.5, 1996, p.517-22 STRUCTURAL FEATURES OF LATEX GLOVES IN DENTAL PRACTICE Tucci M G; Belmonte M M; Toschi E; Pelliccioni G A; Checchi L; Castaldini C; Biagini G; Piana G Ancona, University; Bologna, Universita Using SEM, the morphology and structural features of various types of disposable latex gloves commonly used in Italian dental practice (Biogel D, Trend, Pagni, J&J, Latechnics. Pehasoft, Bantex) were studied. None of the brands examined was free from morphological flaws, but in some of these only slight depressions were found (Biogel D, Trend), while in others there was a marked lack of homogeneity in the latex structure or real holes (Pehasoft). The results of this study emphasised the

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current difficulties faced by dentists in the search for safe working conditions. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.582466 Item 176 148th ACS Rubber Division Meeting. Fall 1995. Conference Preprints. Cleveland, Oh., 17th-20th Oct.1995, Paper 71, pp.20. 012 RUBBER ELASTICITY: THE MAIN CHARACTERISTIC FOR DYNAMIC SHAFT SEALS Dinzburg B Chicago Rawhide Mfg.Co. (ACS, Rubber Div.) A study was made of rubber properties responsible for seal lip followability, or the ability of a shaft seal to follow the shaft wobbling due to eccentricity, as a main factor in seal leakage. The recovery from bending method was used to measure the change of elasticity of various rubbers during ageing in oil, and the results were correlated with seal life. A seal life index including two major properties, elasticity and resistance to lubricated wear, was introduced and shown to give satisfactory correlation with seal life. 24 refs. CR INDUSTRIES USA

Accession no.580254 Item 177 148th ACS Rubber Division Meeting. Fall 1995. Conference Preprints. Cleveland, Oh., 17th-20th Oct.1995, Paper 67, pp.37. 012 FURTHER DEVELOPMENTS IN CRACK GROWTH ANALYSIS OF TYRE COMPOUNDS USING THE BAYER TEAR ANALYSER Sumner A J M; Kelbch S A; Eisele U G Bayer AG (ACS, Rubber Div.) The Bayer Tear Analyser is described, and examples are presented of its use in predicting the cut growth performance of rubber compounds for high performance car tyre treads, car and truck tyre breakers, radial truck tyre treads and truck tyre inner liners. Good correlation between the test results and the service performance of various tyre components is demonstrated. The application of the machine in optimising tyre inner liner formulations based on bromobutyl rubber and blends of bromobutyl and butyl rubber is also described. 6 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; USA; WESTERN EUROPE

Accession no.580250 Item 178 148th ACS Rubber Division Meeting. Fall 1995. Conference Preprints.

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References and Abstracts

Cleveland, Oh., 17th-20th Oct.1995, Paper 22, pp.28. 012 POROSITY IN RUBBER: A REVIEW Kasner A I; Meinecke E A Akron, University (ACS, Rubber Div.) This review of porosity in rubber considers the physics of bubble formation in melts and crosslinked rubbers, the origins of volatile materials, the effects of compounding, mixing and processing, the detection and prevention of porosity, and the effects of porosity on mechanical properties. 174 refs. USA

Accession no.580209 Item 179 Polymat ’94 - Polymers in Extreme Environments II. Conference proceedings. London, 19th-22nd Sept.1994, p.72-5. 93 GAS DIFFUSION INDUCED RUPTURE OF ELASTOMERS Briscoe B J; Savvas T; Kelly C T; Shih W-Y London, Imperial College of Science & Technology (Institute of Materials) Pneumatic stress-induced failures of elastomers are simulated in the laboratory. The samples, polydimethylsiloxane, are saturated with carbon dioxide gas at high pressure and the ambient pressure is rapidly reduced while the processes damage initiation and propagation are monitored visually. In some cases, there appears to be a relation between the failure mechanism and the diffusion of the gas from the sample to the ambient. The reasons for this effect are not clear, although some speculations are provided. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.579609 Item 180 Journal of Adhesion 53, No.3-4, 1995, p.183-99 MECHANICS OF RUBBER-TO-METAL BOND FAILURE Ansarifar M A; Lake G J Malaysian Rubber Producers’ Research Assn. In many applications rubber is bonded to metal for fixing purposes or in order to alter the stiffness, and the integrity of the bond is often vital for maintenance of the required stiffness characteristics and to ensure adequate life. The mechanics of bond failure were studied for various types of deformation. Provided that the tests were carried out under suitable loading conditions, time-dependent failure with a similar locus was observed in peeling at 90 or 180 degrees, pure shear and various combinations of simple shear and compression. There were indications that an energetics approach could enable results from different geometries to be quantitatively interrelated. Cavitation-

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like processes observed in the rubber in the bond region were thought to result from the constraint imposed by the metal and could be the cause of the time-dependent failure. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.566630 Item 181 Rubber and Plastics News 24, No.19, 10th April 1995, p.6 OPEL ASTRA FIRES LEAD TO STUDY OF MICHELIN’S SILICA-BASED TIRES Davis B This article reports that insufficient conductivity of Michelin’s “green” tyres is being investigated as a possible cause of an electrostatic build-up on Opel Astra compacts, that has led to flash fires during fuelling, all of which have occurred in Germany. Details of the situation are provided. MICHELIN; MICHELIN NORTH AMERICA; OPEL AG EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.561248 Item 182 Rubbercon ’95. Conference Preprints. Gothenburg, 9th-12th May 1995, Paper E4, pp.14. 012 FATIGUE LIFE CALCULATIONS FOR ELASTOMERIC ENGINEERING COMPONENTS Stevenson A; Harris J A; Hawkes J; Becker E; Miller T; McMullen R Materials Engineering Research Laboratory Ltd.; Mechanics Software Inc. (Nordic Council of Rubber Technology) The use of the FLEXPAC finite element code for fatigue life predictions of rubber components is described. Materials models are input for elasticity, stress softening and fatigue crack growth behaviour, and solutions are obtained for cracks growing within rubber layers under different modes of deformation. These solutions give tearing energy values associated with the growth of cracks in various locations. The materials fatigue model, an input fatigue spectrum and solutions for tearing energy are then used to compute the amount of crack growth as a function of cycle number or time. An example of the fatigue calculations is presented for a model bearing under a biaxial combination of shear and compression deformations. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; SWEDEN; UK; USA; WESTERN EUROPE

Accession no.560450 Item 183 Rubbercon ’95. Conference Preprints. Gothenburg, 9th-12th May 1995, Paper E1, pp.20. 012

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MATERIALS DATA FOR DESIGN Coveney V A; Jamil S West of England, University (Nordic Council of Rubber Technology) Based on work undertaken in the UK within the Engineering with Elastomers project of the Design Data Initiative for Polymeric Materials, a study is made of mechanical properties data requirements for the design of rubber products. Results are presented of a survey among UK rubber products manufacturers of test methods used. These show that although a significant number perform dynamic tests, the proportion using the British Standard for such tests is much lower. Comparison of the findings of this survey with those of a previous study suggests that some BS 903 tests may be redundant. Work on the analysis of double shear test specimen arrangements and servohydraulic test machines is outlined. 25 refs. BRMA; BPF; UK, DEPT.OF TRADE & IND. EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; SWEDEN; UK; WESTERN EUROPE

Accession no.560447 Item 184 Rubber Chemistry and Technology 68, No.2, May-June 1995, p.197-211 FRACTURE OF ELASTOMERS BY GAS DECOMPRESSION Stevenson A; Morgan G Materials Engineering Research Laboratory A study was made of gas decompression failures in elastomeric seals using a fracture mechanics approach with considerations of gas permeation. An equation is proposed for the tearing energy associated with crack growth from internal gas bubbles in a finite thickness elastic media. The effects of gas pressure, temperature, rate of decompression and mechanical strain were studied for a range of elastomers used in oil and gas sealing applications. A theoretical treatment is presented based on a fracture mechanics criterion for fracture from an internal disc shaped flaw in a thick elastic medium. Permeation theory provides a quantification of the amount of gas available internally to initiate failures. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.559811 Item 185 International Polymer Science and Technology 22, No.3, 1995, p.T/74-83 ANALYSIS OF INDUSTRIAL RUBBER PARTS: STUDIES OF THERMAL ANALYSIS FOR INDUSTRIAL TROUBLE SHOOTING Ohtake Y; Furukawa M The potential of thermal analysis is reviewed, particularly TGA and DSC, presenting actual examples of analysis

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with reference to faults that have actually occurred in industrial rubber components. 23 refs. Translation of Nippon Gomu Kyokaishi, No.12, 1993, p.895 JAPAN

Accession no.558233 Item 186 Kautchuk und Gummi Kunststoffe 48, No.6, June 1995, p.423-9 APPLICATION OF FEA ON TEXTILE REINFORCED RUBBER STRUCTURES AS USED IN AIR SPRINGS Massmann C ContiTech Luftfedersysteme GmbH The deformation behaviour of rolling lobe air springs was investigated by applying finite element analysis on different modelling levels. Correlations are given between calculated data for stress-strain states and observed lifetimes and failure phenomena of samples. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.554893 Item 187 China Synthetic Rubber Industry 18, No.3, 1995, p.162-3 Chinese ADHESION FAILURE OF RUBBER-BASED PRESSURE-SENSITIVE ADHESIVE Gangzhi J; Zhaowei L; Ancheng P; Zuoshu W; Zhongqin S Lanzhou Chemical Industry Corp. The causes of the adhesion failure of rubber-based pressure-sensitive adhesives were studied. The results showed that the resistance of adhesion failure decreased with increase in the amount of tackifier. The resistance of adhesion failure increased on addition of 0.5 to 1.0 phr of polyphenol antioxidant. The synergistic effect of oxygen and/or ozone in the atmosphere with UV light also led to failure of the adhesives. CHINA

Accession no.552653 Item 188 Revue Generale des Caoutchoucs et Plastiques No.734, Sept.1994, p.68-70 French SURFACE DEFECTS AND MICROSTRUCTURE OF HEAT CURABLE SILICONE ELASTOMERS Varlet J; Pouchelon A; Bourrain P; Joachim F Rhone-Poulenc SA Results are presented of a capillary rheometer study of the influence of extrusion conditions and rheological properties on defects occurring on the surface of heat curable polydimethyl siloxane extrudates. 4 refs.

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References and Abstracts

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.552429

of the composites. The level of strain to failure and the rate of cyclic strain increase were also measured in order to establish the fatigue failure criteria. 16 refs. USA

Item 189 Industria della Gomma 38, No.5, May 1994, p.40-3 Italian CAR TYRES. V. Assogomma Procedures for the maintenance of car tyres in service and in storage are presented, and aspects of tyre performance and types and causes of irregular wear and accidental damage are discussed. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.552404 Item 190 147th Meeting, Spring 1995, Conference Preprints. Philadelphia, Pa., 2nd-5th May 1995, Paper 8, pp.14. 012 EFFECT OF TORSIONAL STIFFNESS ON THE FATIGUE LIFE OF MILITARY TRACK BUSHINGS Ruonavaara N; Simula G; Hedberg D; Saxon M Michigan, Technological University; US, Army (ACS, Rubber Div.) The relationship between torsional stiffness, aspect ratio and compression ratio and the fatigue life of rubber bushings for military vehicle track systems is discussed. Results are presented of tests conducted on traditional and prototype bushing designs using a laboratory endurance simulation machine, and which suggest that the endurance life is more sensitive to changes in torsional stiffness (shear strain) than radial stiffness (compressive stress). 5 refs. USA

Accession no.552348 Item 191 147th Meeting, Spring 1995, Conference Preprints. Philadelphia, Pa., 2nd-5th May 1995, Paper 2, pp.24. 012 CUMULATIVE DAMAGE AND FATIGUE FAILURE CRITERIA OF CORD-RUBBER COMPOSITES Lee B L; Ku B; Liu D S Pennsylvania, State University (ACS, Rubber Div.) The effect of minimum stress on fatigue life at a given stress range was assessed for angle-ply steel wirereinforced rubber composites representing radial tyre belts. A series of S-N curves was generated with the minimum stress kept constant. The levels of minimum stress ranged up to 50% of the ultimate tensile strength

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Accession no.552345 Item 192 Rubber and Plastics News 24, No.18, 27th March 1995, p.30-1 POLYURETHANES: ACHIEVING TOP PERFORMANCE Oster K R Air Products & Chemicals Inc., PU Specialty Prod.Div. The manufacture of polyurethane prepolymers is discussed, and details are included of their storage, shelf life, melt time, heat stability, curing agents, and levels of curative. The machinability of polyurethane elastomers, design suggestions, use in food handling applications, and common causes of failure are also examined. USA

Accession no.549770 Item 193 Rubber Chemistry and Technology 67, No.5, Nov/Dec.1994, p.892-903 ELASTOMERIC EJECTION SYSTEM Choi I S; Roland C M; Bissonnette L C US, Naval Research Laboratory; US, Navy, Undersea Warfare Center The material requirements for an elastomeric torpedo launcher were examined, most of the considerations being relevant to energy storage devices in general. The main properties governing an elastomer’s performance in this regard were the magnitude of elastic (recoverable) energy which, together with geometry, governed the attainable power, the propensity of the rubber to creep, which depleted the stored energy, and the failure properties, which determined the device’s lifetime. Resistance to deterioration by seawater was also studied. 41 refs. (ACS Rubber Division Fall Meeting, Pittsburgh, Oct.1994) USA

Accession no.547321 Item 194 Biomaterials 16, No.4, 1995, p.279-85 CALCIFICATION AND FATIGUE FAILURE IN A POLYURETHANE HEART VALVE Bernacca G M; Mackay T G; Wilkinson R; Wheatley D J Glasgow, Royal Infirmary; Strathclyde, University Prosthetic heart valves were fabricated from a PU containing a 4, 4'-diphenylmethane diisocyanate hard segment, chain-extended with butanediol and with a polyether soft segment. The rate of calcification of these PU heart valves was much slower in a dynamic in vitro

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test system than similar bioprosthetic heart valves. The calcified deposits were located exclusively at regions of material failure. FTIR spectroscopy indicated the involvement of the polyether soft segments of the polymer directly in the calcification process. Calcification of polymer fractions also suggested that small molec.wt. extractable components were accelerating factors in the calcification process. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.545742 Item 195 Rubber World 211, No.5, Feb.1995, p.22-6 PREVENTING POLYMER DEGRADATION DURING MIXING Mazzeo R A Uniroyal Chemical Co.Inc. Elastomers are subject to atmospheric oxidation, even at moderate temperatures. The ease of susceptibility to degradation depends, to a large degree, upon structure and environmental exposure. This article deals primarily with the prevention of polymer degradation during mixing and examines the effects of oxygen, ozone and shear, heat, light and weathering, metals and fatigue. Antioxidants do not completely eliminate oxidative degradation, but they markedly retard the rate of autoxidation by interfering with radical propagation. Depending on the types and combinations used, antioxidants can provide suitable polymer protection during the phases of its life cycle. The two categories of antioxidants, primary and secondary, are discussed. 3 refs. USA

Accession no.545435 Item 196 Nippon Gomu Kyokaishi 67, No.5, 1994, p.339-47 Japanese O-RINGS Tsuda F NOK Corp. A brief categorisation is given of the different types of seals in use, and a description is given of the properties, mode of operation and causes of failure of O-rings. 5 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.542429 Item 197 Muanyag es Gumi 31, No.5, 1994, p.133-6 Hungarian

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GENERAL FEATURES AND APPLICATIONS OF PERCOLATION THEORY FOR RUBBER PHYSICS. V. USE OF DIRECTED PERCOLATION IN RUBBER PHYSICS Baricza K Hungarian Academy of Sciences The author explains how, in the case of crack growth on the surface of rubber products, the failure is a totally directed percolation problem. Gas transport in rubbers can be described by a dynamically interpreted partly directed edge percolation, where the specific direction is determined by the pressure gradient causing the gas flow. 2 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. EASTERN EUROPE; HUNGARY

Accession no.542427 Item 198 Kauchuk i Rezina (USSR) No.2, 1994, p.44-6 Russian IMPROVING THE DESIGN OF THE RUBBER ELEMENT OF A DIAPHRAGM VALVE Kaporovskii B M; Azarkh M Z; Yurtsev N N Analysis is presented of the operation of two types of diaphragm valves normally made of rubber or rubber combined with a fabric, which are subjected to the effect of high temperatures (415C) when used in the food industry or biotechnology. The effect of high temperatures on the failure of the rubber is explained and suggestions are given for improvement of the design. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. RUSSIA

Accession no.542402 Item 199 Journal of Inorganic & Organometallic Polymers 4, No.4, Dec.1994, p.425-30 IMPROVEMENT OF THE ADHESION OF SILICONE TO ALUMINIUM USING PLASMA POLYMERISATION Costantino G; Zeik D B; Clarson S J Cincinnati, University The adhesion-in-peel test was used to determine peel strength and adhesion characteristics of a cured-in-place silicone elastomeric joint sealant on aluminium substrates. The sealant used was Dow Corning Type 3145 RTV Adhesive Sealant. The results showed that the silicone sealant had poor adhesive bonding to the untreated aluminium. Plasma polymerisation of hexamethyldisiloxane(HMDS) onto the aluminium was shown to move the locus of adhesive failure to between the plasma film and the silicone. Plasma polymerisation of HMDS

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References and Abstracts

with oxygen carrier gas produced good adhesion and cohesive failure in the silicone was observed. 17 refs. DOW CORNING CORP. USA

Accession no.538312 Item 200 146th Meeting, Fall 1994, Conference Proceedings. Pittsburgh, Pa., 11th-14th Oct.1994, Paper 82, pp.12. 012 RUBBER FOOTWEAR: APPLICATIONS AND MANUFACTURE Devasthali P Norcross Footwear Inc. (ACS, Rubber Div.) An examination is made of the manufacture, properties and testing of rubber footwear, particularly safety footwear. 4 refs. USA

Accession no.535556 Item 201 146th Meeting, Fall 1994, Conference Proceedings. Pittsburgh, Pa., 11th-14th Oct.1994, Paper 66, pp.37. 012 MIXING OF RUBBER AND VISCOELASTICITY. IV. VISCOELASTIC CHARACTERISATION OF COMPOUND Nakajima N Akron, University, Inst.of Polym.Engineering (ACS, Rubber Div.) Viscoelastic methods for the characterisation of gum rubbers are extended to rubber compounds, and the ways in which the viscoelastic properties of gum rubbers are manifested in the properties of the corresponding compounds are examined. The development of a method for evaluating strain amplification and strain rate amplification is described. Examples are presented of the characterisation of compounds with respect to variations in gum rubbers and carbon black grades, and consideration is given to the unique characteristics of compounds which are not observed in gum rubbers. Quality control tests for gum rubbers and compounds based on viscoelasticity are reviewed. 32 refs. USA

Accession no.535540 Item 202 146th Meeting, Fall 1994, Conference Proceedings. Pittsburgh, Pa., 11th-14th Oct.1994, Paper 60, pp.18. 012 GAS-INDUCED EXPLOSIVE DECOMPRESSION IN ELASTOMERS Stevenson A Materials Engineering Research Laboratory Ltd. (ACS, Rubber Div.)

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Explosive decompression failures in nitrile rubber, fluoroelastomer and tetrafluoroethylene-propylene copolymer seals for the oil industry were studied by a fracture mechanics approach and considerations of gas permeation. An equation was proposed for the tearing energy associated with internal blisters in a finite thickness elastic medium. When applied to a model experiment where an internal flaw of known size was pressurised up to failure, the equation correctly predicted the catastrophic fracture stage. A series of seals were subjected to high gas pressures at a range of temperatures and the amount of crack growth after decompression was determined. The trends in failure pressure were correctly accounted for when appropriate tearing energy values were used for the temperature of decompression. The effects of mechanical boundary constraint and decompression rate were also examined. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.535534 Item 203 146th Meeting, Fall 1994, Conference Proceedings. Pittsburgh, Pa., 11th-14th Oct.1994, Paper 58, pp.18. 012 NITRILE RUBBER: PAST, PRESENT AND FUTURE Hertz D L; Bussem H; Ray T W Seals Eastern Inc.; Halliburton Energy Services Inc. (ACS, Rubber Div.) Studies of chemical attack on nitrile rubber by fluids encountered in sealing applications in the oil industry are reported. The results showed that excessive hardening of nitrile rubber in the downhole oilfield environment occurs at the acrylonitrile sites, and that it could be due to either hydrolysis or reduction of the cyano group. Hydrolysis is driven by Bronsted acids (proton donors) and reduction by Lewis acids (electron donors). Catalysis by metal ions could possibly cause these reactions to occur at a greatly reduced activation energy. Oxidative attack at the butadiene sites is the primary cause of hardening in aboveground applications of nitrile rubber. 12 refs. USA

Accession no.535532 Item 204 146th Meeting, Fall 1994, Conference Proceedings. Pittsburgh, Pa., 11th-14th Oct.1994, Paper 57, pp.15. 012 WHAT DO END USERS OF OILFIELD ELASTOMER SEALS REALLY WANT? Abrams P I Exxon Production Research Co. (ACS, Rubber Div.) Service requirements for rubber seals used in the oil industry are examined, and examples are presented of costs incurred as a result of seal failure or poor

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performance. The involvement of end users of such seals in materials selection and testing is discussed. 6 refs. USA

Accession no.535531 Item 205 Journal of Adhesion 47, No.1-3, 1994, p.51-64 INTERFACIAL CHEMISTRY OF AN ALUMINIUM-TO-EPDM BONDING SYSTEM Hemminger C S Aerospace Corp. During recent examinations of ageing in aluminium-torubber bonds on stored solid rocket motors, corrosion and minor insulator debonds were observed. A test was conducted to study the progressive effect of exposure to high humidity of the bondline, elevated temp. being used to accelerate the ageing. In a parallel test, samples were held at elevated temp. in a dry atmosphere. The test results were compared with the analyses of corroded and non-corroded hardware samples. The predominant corrosion product detected at the bondlines was aluminium oxide/hydroxide. In general, there was a very good correlation between the Cl:Al atomic percent ratio calculated from X-ray photoelectron spectroscopy analysis of the ruptured bondline surfaces and the visual characterisation of the extent of corrosion. The Cl:Al ratio, which represented the ratio of primer to corrosion product at the locus of failure, varied from 0.4 to 47. The implications for metal-to-rubber bond fabrication and storage are discussed. 3 refs. (Adhesion Society Inc., 16th Annual Meeting, Williamsburg, Virginia, USA, Feb.1993) USA

Accession no.532160 Item 206 International Polymer Science and Technology 21, No.7, 1994, p.T/1-13 DESIGN OF REINFORCED HIGHPERFORMANCE HOSES Hufenbach W; Kroll L; Holste C The design of reinforced high-performance hoses is discussed with reference to stress-adapted hose structures, reinforced elastomer hoses, calculations for hose structures with anisotropic reinforcement, examples of calculations (calculations for asymmetric hose structures, calculating the maximum stress for cord-reinforced elastomer layers, calculation of the maximum normal and shear stresses in relation to the thread orientation), failure mechanisms in anisotropic layer composite structures, and finite element calculations. 33 refs. (Full translation of Gummi Fas.Kunst., No.3, 1994, p.158) EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.532122

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Item 207 Polymer Plastics Technology and Engineering 33, No.5, 1994, p.537-50 MODELLING OF CHANGES IN CROSSLINKING FOR STRUCTURAL SILICONE SEALANTS SUBJECTED TO MOISTURE AND SUNLIGHT Keshavaraj R; Tock R W Texas, Technical University The effects of moisture and solar radiation on a structural silicone sealant were correlated through crosslinking changes. A typical weathering event consisted of exposing sets of test coupons to moisture having different pH levels ranging from 3 to 11, simulating acid rain (pH 3) and cleaning solutions (pH 11). The exposure to moisture was followed by drying outdoors in the sunlight. The experimental data suggested that moisture alone can trigger additional crosslinking in silicone sealants, but that the simultaneous effect of moisture with sunlight can be detrimental. As a result of exposure, a gradual deterioration of the physical properties of the sealants were observed. A chemical-kinetic model of the degree of crosslinking as a function of exposure time was developed to predict the onset of failure due to these ageing factors. A semiempirical approach was used to estimate the chemical-kinetic rates and other parameters from the experimental data. The development of the hypothetical mechanism used for modelling the time variations in crosslink density is described. 16 refs. USA

Accession no.529911 Item 208 BHR Group News Summer 1994, p.4 SOFTWARE PREDICTS ELASTOMERIC SEAL LIFE This article reports on new unique seal life prediction software, developed by BHR Group to predict explosive decompression and material degradation. Successful application to a 140mm diameter seal in a down-hole flapper valve in service in the North Sea is described. BHR GROUP EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.523192 Item 209 Journal of Biomedical Materials Research 28, No.7, July 1994, p.819-29 THEORETICAL ANALYSIS OF IN-VIVO MACROPHAGE ADHESION AND FOREIGN BODY GIANT CELL FORMATION ON STRAINED POLY(ETHERURETHANE UREA) ELASTOMERS Kao W J; Hiltner A; Anderson J M; Lodoen G A

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References and Abstracts

Case Western Reserve University To correlate the kinetics of foreign body giant cell formation on polyether urethane surfaces and the extent of environmental stress cracking, a theoretical model was applied to strained polyether urethanes containing an antioxidant and an antifume agent. Through low voltage SEM, environmental stress cracking phenomena were observed, semiquantified, and correlated with theoretical analysis. The morphology of the adherent cells provided further information on the state of cellular activity. Alterations in polyether urethane surface topography at the cell-polymer interface were used to assess the effects of adherent cells on environment stress cracking. 35 refs. USA

Accession no.517163 Item 210 Archives of Environmental Health 49, No.3, May/June 1994, p.151-3 SILICONE BREAST IMPLANTS AND AUTOIMMUNITY: CAUSATION OR MYTH? Brautbar N; Vojdani A; Campbell A Southern California, University; Drew University; Center for Immune, Environmental & Toxic Disorders This detailed paper explores the possible connection between silicone breast implants and autoimmunity. It considers animal data, human data, evidence that implants leak, and evidence that silicone is immunogenic. It is concluded that clinical studies, patient reports, immunological studies, and experimental studies show a definite causation between silicone and the disease process. 28 refs. US, FOOD & DRUG ADMINISTRATION USA

Accession no.516039 Item 211 Advances in Polymer Technology 13, No.2, Summer 1994, p.149-56 OXIDATIVE EFFECTS OF OZONE ON THE AGEING OF STRUCTURAL SILICONE ELASTOMERS Keshavaraj R; Tock R W Texas, Technical University The changes in the physical properties of three different silicone sealants used in structural glazing applications were monitored as a function of various ageing factors. The variables included simultaneous exposure to ozone and moisture in which the pH of the moisture was maintained at discrete levels of 3 and 11. The extremes of the pH range represented recorded values for acid rain and basic cleaning solutions. The effect of loading on the sealant performance was also investigated. An Instron tester was used to measure the changes in the engineering properties such as Young’s modulus, relaxation time and ultimate tensile stress of the test

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samples as a function of time of exposure to the different variables. 12 refs. USA

Accession no.512806 Item 212 European Rubber Journal 176, No.5, May 1994, p.26 HNBR ATTACKS THE OIL FIELD SECTOR Shaw D Manufacturers of hydrogenated nitrile rubbers are seeking new applications in down-hole seals for oil wells. Nippon Zeon claims the superior strength and compounding flexibility of HNBR yields better in-service performance than more expensive, but relatively weak fluoroelastomers. Its Zetol range of HNBR elastomers are compatible with typical oilfield chemicals and strong. Strength is important in these applications because of the risk of explosive decompression. NIPPON ZEON CO.LTD. USA

Accession no.512685 Item 213 145th Meeting, Spring 1994. Conference Proceedings. Chicago, Il., 19th-22nd April 1994, Paper 31, pp.37. 012 FUNCTIONS AND MECHANISMS OF ANTIDEGRADANTS TO PREVENT POLYMER DEGRADATION Mazzeo R A; Boisseau N A; Hong S W; Wheeler E L Uniroyal Chemical Co.Inc. (ACS, Rubber Div.) An examination is made of the mechanisms of rubber degradation, types of antiozonants and antioxidants used in rubbers, and the mechanisms by which they prevent polymer degradation. 10 refs. USA

Accession no.511437 Item 214 Eureka 14, No.2, Feb.1994, p.57-8 DESIGNING YOUR WAY TO RELIABLE SHAFT SEALS Barrett J The causes of hydraulic seal failure are analysed and some design advice is offered. The causes discussed include unsuitable surfaces, gap extrusion, back pressure, cavitation, installation and start-up, gaseous contaminants, dieswelling, solids contamination, effects of contamination, wear due to adhesion, wear due to abrasion and wear due to erosion. Accession no.506118

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Item 215 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 96, pp.28. 012 STUDY FOR THE PREDICTION OF THE LONGTERM DURABILITY OF SEISMIC ISOLATORS. II. Fujita T; Ishida K; Mazda T; Sueyasu T; Nishikawa I Tokyo, University; Japan, Central Res.Inst.of the Electric Power Ind.; Bridgestone Corp.; Showa Electric Wire & Cable Co.Ltd. (ACS, Rubber Div.)

Item 217 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 89, pp.19. 012 CONTINUOUS IMPROVEMENT IN THE COMPOUNDING OF SILICONE RUBBER Eloph C E; Nesler D M Dow Corning STI Midwest (ACS, Rubber Div.)

Test methods for assessing the long-term durability of NR vibration dampers for earthquake protection were investigated. Since heat aged NR blocks showed evidence of heterogeneous degradation, with one area near the surface where oxidative degradation produced large changes in properties and another in the interior where thermal degradation resulted in only small property changes, difficulties were experienced in predicting durability by conventional methods. An accelerated ageing method was proposed, and techniques for simulating the property profile were considered. An indirect method using a shift of time, temperature and distance and a direct method for estimating the distribution of properties both gave good simulation results. 8 refs.

USA

JAPAN; USA

Accession no.505672 Item 216 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 95, pp.23. 012 STUDY FOR THE PREDICTION OF THE LONGTERM DURABILITY OF SEISMIC ISOLATORS. I. Fujita T; Mazda T; Muramatsu Y; Hamanaka T; Yoshizawa T Tokyo, University; Japan, Central Res.Inst.of the Electric Power Ind.; Showa Electric Wire & Cable Co.Ltd.; Bridgestone Corp. (ACS, Rubber Div.) In order to develop a test method for the durability of vibration dampers for earthquake protection, a study was made of the depth-dependent profiles of tensile properties in thick NR blocks after heat ageing at 60-100C. The blocks showed evidence of heterogeneous degradation, i.e. an oxidatively degraded area near the surface showing large changes in properties, and a thermally degraded area in the interior showing small property changes. The depth of oxidation showed temperature dependence, with a greater depth at lower temperatures. There was also a linear relationship between the logarithm of the oxidation depth and the reciprocal of the absolute temperature. The activation energy held a fixed value independent of depth. 7 refs.

Details are given of quality control procedures used by Dow Corning STI Midwest in silicone rubber compounding. Accession no.505667 Item 218 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 83, pp.29. 012 CHLORAMINE EFFECTS ON ELASTOMER DEGRADATION Reiber S HDR Engineering Inc. (ACS, Rubber Div.) A study was made of the effects of chloramine disinfectants and free chlorine in water on rubber mechanical parts used in water distribution systems. Tests were undertaken to investigate swelling, surface cracking and loss of elasticity and tensile strength of specimens based on NR, SBR, polychloroprene, nitrile rubber, EPDM, butyl rubber, fluoroelastomers and silicone rubbers. 9 refs. USA

Accession no.505662 Item 219 IRC ’93/144th Meeting, Fall 1993. Conference Proceedings. Orlando, Fl., 26th-29th Oct.1993, Paper 63, pp.31. 012 DEVELOPMENT OF NEW HNBR ELASTOMERS FOR USE IN REFRIGERANT R-134A Aimura Y; Recchio M; Konno T; Jones M; Hayashi S Nippon Zeon Co.Ltd.; Zeon Chemicals Inc. (ACS, Rubber Div.) Hydrogenated nitrile rubbers were evaluated for use in seals and hoses for automotive air conditioning systems. Studies were made of the resistance of these materials to hydrofluorocarbon refrigerants and polyalkylene glycol and mineral oil based lubricants, and permeation resistance, explosive decompression and low temperature performance characteristics were investigated. Designed experiments were undertaken to study the effect of compounding techniques on permeation and explosive decompression. 4 refs.

JAPAN; USA

JAPAN; USA

Accession no.505671

Accession no.505651

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References and Abstracts

Item 220 Plastics & Rubber & Composites Processing & Applications 19, No.4, 1993, p.245-54 DEVELOPMENT AND FIELD PERFORMANCE OF TANK TRACK PAD COMPOUNDS Thavamani P; Khastgir D K; Bhowmick A K Indian Institute of Technology The development of suitable compounds by optimising critical properties, manufacturing, field testing, failure analysis and mechanism of wear of tank track pads for a battle tank are described. Four compounds based on NR, SBR, NR/SBR and hydrogenated nitrile rubber were developed with optimum physical properties. 19 refs. INDIA

Accession no.505518 Item 221 Nippon Gomu Kyokaishi 66, No.12, 1993, p.847-55 Japanese A GENERAL INTRODUCTION: BASIC APPROACHES AND CURRENT STATE OF PROBLEM ANALYSIS OF RUBBER PRODUCTS Nakauchi H Bridgestone Industries Ltd. Tables are given listing categories of rubber mix ingredients and analysis methods, together with types of analysis of problems in end products. 3 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. JAPAN

Accession no.503820 Item 222 Adhesives Age 37, No.1, Jan.1994, p.26-7 SWITCHING SEALANTS ENHANCES VAN CONVERTER’S IMAGE Explorer Van Co. has recently switched to Norton Performance Plastics’ Norex butyl-coated foam (BCF) tape as the primary sealant between the fibreglass roof caps and bodies on all its custom-made vans. Previously the company sealed with solid butyl tape backed with silicone caulk. Before the switch in sealants, an average of three vans a month were returned for warranty repairs because of leaky caps. Besides reducing the warranty repair expense, the company only uses half as much silicone caulk, saving about 10 US dollars per vehicle in materials and labour. NORTON PERFORMANCE PLASTICS CORP.; EXPLORER VAN CO. USA

Accession no.503489

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Item 223 Polyurethanes World Congress 1993. Conference Proceedings. Vancouver, B.C., 10th-13th Oct.1993, p.279-87. 43C6 UNDERSTANDING THE FUNDAMENTALS OF FORCED COOLING IN THE PRODUCTION OF BLOWING AGENT FREE FLEXIBLE SLABSTOCK POLYURETHANE FOAMS McAfee C D; Wiltz E P; Skorpenske R G; Ridgway D H; McClusky J V Dow Chemical Co. (SPI, Polyurethane Div.; SPI Canada Inc.; European Isocyanate Producers Assn.) Results of forced cooling experiments on water blown PU foam on the Varimax half scale pilot line are presented, with emphasis on avoiding discolouration and degradation. As well as optimising procedures, some formulation improvements were discovered, i.e. novel polyols, modifiers and catalysts. 9 refs. USA

Accession no.502768 Item 224 Revue Generale des Caoutchoucs et Plastiques 70, No.727, Nov.1993, p.78-83 French RUBBER COMPOUNDS IN CONTACT WITH WATER Harmsworth N Bayer AG Tests for the resistance to microbiological attack of rubbers in water contact applications are examined, with reference to standards in the UK and Germany. The influence of rubber type, additives and vulcanisation processes on microbiological resistance is discussed, and requirements for rubber components in contact with potable water are also reviewed. 5 refs. EUROPEAN COMMUNITY; GERMANY; UK; WESTERN EUROPE

Accession no.501140 Item 225 Rubber World 208, No.6, Sept.1993, p.22-4 ELASTOMERS IN AUTOMOTIVE FUELS, OILS AND FLUIDS AT HIGH TEMPERATURES Hertz D L Seals Eastern Inc. The effects of automotive fuels, oils and fluids on different elastomers when subjected to the various operating environments including fuels, engine lubricants, automatic transmission fluids, power steering fluids, engine coolants and refrigerants, are discussed. The chemical and physical responses of the basic elastomers and the elastomer compounds are not only logical but also predictable. It is claimed better test methods utilising

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References and Abstracts

ion analysis, infrared spectroscopy, physical testing and dynamic mechanical rheological testing should be considered. 15 refs. USA

Accession no.497277 Item 226 Rubber World 208, No.6, Sept.1993, p.16-7 STUDY OF USAF AIRCRAFT FUEL/SEAL LEAKAGE Fletcher A; Lawless G W Dayton, University, Research Institute; US, Air Force Materials Laboratory This article discusses in brief and general terms the application of the o-ring as an aircraft fuel seal. Traditional o-rings generally work quite well as aircraft fuel seals, but the varieties of different fuels and flight conditions do present a spectrum of shifting demands. For many years either the nitrile or the fluorosilicone elastomer has been used for aircraft fuel seals and both of these elastomers, from a physical property/fuel compatibility point of view, offer the possibility of successful sealing. It is the sudden change from one fuel media to another, referred to as “switch loading”, that is thought to be especially troublesome as different environments of chemistry and physics are rapidly presented to the seal. USA

Accession no.497276 Item 227 Plaste und Kautschuk 39, No.6, June 1992, p.199-202 German MECHANICAL DESTRUCTION OF RUBBERS DURING PROCESSING Vol’fson S I; Karp M G; Meissmer K Merseburg, Technische Hochschule; Kasan, Chemicotechnological Institute This paper discusses the extrusion of isoprene rubber, where mechanical destruction processes predominate at lower temperatures and thermooxidation destruction processes predominate at higher temperatures. As a result of these destruction processes, the molecular weight at the end of the mixing process is an important factor in determining the processing- and end-use properties. A series of SKI-3 compounds were tested to investigate the effect on their molecular weight. EUROPEAN COMMUNITY; GERMANY; RUSSIA; WESTERN EUROPE

Accession no.490295 Item 228 Rubber World 208, No.3, June 1993, p.19/32 LATEX FILMS ARE BARRIERS TO VIRUSES

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Morris M D; Pendle T D Malaysian Rubber Producers’ Research Assn. Details are presented of the evidence for and against the pore hypothesis in condoms. This follows an article by C.M.Roland discussing the barrier performance of latex rubber (Rubber World, 208, No.3, June 1993, p.15-8). Briefly mentioned is the testing of condoms for holes. 6 refs. MALAYSIA

Accession no.488869 Item 229 Rubber World 208, No.3, June 1993, p.15-8 BARRIER PERFORMANCE OF LATEX RUBBER Roland C M US, Naval Research Laboratory A review is presented of the use of condoms in the prevention of spreading sexually transmitted diseases. The testing of condoms for leakage is discussed as well as the testing of defects in latex rubber used in condoms and gloves. 57 refs. USA

Accession no.488868 Item 230 Eureka 13, No.4, April 1993, p.7 RUBBER BEARING SEAL FILTERS FINE PARTICLES A new type of rubber bearing seal has been developed by NSK Bearings, to combat the problem of premature failing of bearings caused by surface fatigue. The Sealed Clean concept is designed more as a filter than an oil seal. The seal geometry allows small amounts of transmission oil to enter the bearing, but filters out any foreign particles that are in suspension. NSK BEARINGS EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.479064 Item 231 Biomaterials 14, No.6, May 1993, p.459-64 BIODETERIORATION OF MEDICAL-GRADE SILICONE RUBBER USED FOR VOICE PROSTHESES: A SEM STUDY Neu T R; Van der Mei H C; Busscher H J; Dijk F; Verkerke G J Groningen, University; Netherlands, Biomedical Technology Centre Silicone voice prostheses used for rehabilitation of speech after total laryngectomy are inserted in a non-sterile habitat. Deposits on explanted Groningen Button voice

© Copyright 2002 Rapra Technology Limited

References and Abstracts

prostheses revealed a biofilm, the result of colonisation of the silicone surface by bacteria and yeasts. Furthermore, it was shown by SEM on sectioned explants that the silicone material was degraded by filamentous and vegetative yeast cells. The different explants showed a variety of sharp-edged, discrete yeast colonies. The yeasts grew just under the silicone surface and up to 700 microns into the silicone material. Nine different types of defect in the silicone material created by the yeasts are described. This degradation of the silicone by yeasts appeared to be the main cause of failure and of the need for frequent replacement of the prostheses. 10 refs.

Explosive decompression is a failure mode in elastomers - usually seals - in which large bubbles of gas suddenly swell up in the middle of elastomeric materials, often causing gross, catastrophic failure of the component. Good design and compounding, however, can alleviate the problem. An outline of papers presented at a recent seminar covering this topic at the Imperial College of Science, Technology & Medicine in London is given. AKRON, UNIVERSITY, INST.OF POLYM.ENGINEERING; MATERIALS ENGINEERING RESEARCH LABORATORY LTD.; BP CHEMICALS LTD.

EUROPEAN COMMUNITY; NETHERLANDS; WESTERN EUROPE

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.478732 Item 232 Journal of Thermal Insulation Vol.16, Jan.1993, p.293-300 SAMPLE POLYURETHANE FOAM ROOFS Morrison R V North Carolina Foam Industries The three common methods of sampling foam roofs, i.e. slit sampling, core sampling and modified core sampling, are described and the use of foam sampling to determine thicknesses of the foam passes or coatings, adhesion of the sprayed foam to the substrate, foam-to-foam knit lines and quality of the cellular structure of the foam itself is discussed. USA

Accession no.478666 Item 233 Progress in Organic Coatings 21, No.4, 15th March 1993, p.315-25 ACCELERATED DEGRADATION OF A CHLORINATED RUBBER PAINT SYSTEM APPLIED OVER RUSTED STEEL Morcillo M; Simancas J; Fierro J L G; Feliu S; Galvan J C Centro Nacional de Investigaciones Metalurgicas A study was made of the premature failure of a chlorinated rubber system applied directly over contaminated rusted steel. The accelerated formation of rust at the steel/paint interface rapidly resulted in complete degradation of the organic coating. Interfacial rust appeared to catalyse the cleavage of the C-Cl covalent bonds in the polymer, giving rise to the formation of chloride ions, which had a dramatic accelerating effect on the corrosion of the base steel. 24 refs. EUROPEAN COMMUNITY; SPAIN; WESTERN EUROPE

Accession no.478419 Item 234 European Rubber Journal 175, No.5, May 1993, p.31 ED AND HOW TO AVOID IT Shaw D

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Accession no.477625 Item 235 International Seminar on Elastomers. Seminar Proceedings. Kurume, 7th-9th Oct.1990, p.359-67. 012 LIFE TIME-AFFECTING FACTORS OF RUBBER PRODUCTS, SUCH AS HOSES Samay G; Palotas L; Nagy T; Seregely Z Taurus Hungarian Rubber Works Edited by: White J L; Murakami K (Akron, University; Teikyo, University) Applied Polymer Symposium 50 The various methods for lifetime prediction are reviewed and the key deteriorating factors identified as environmental and mechanical effects. The breaking energy is shown to be a good measure of the extent of environmental ageing for various rubbers under very different conditions, such as weathering and ageing in sea water, oil and H2S. If fatigue of the reinforcement is the lifetime limiting factor, an exact stress analysis is required for lifetime prediction. 7 refs. EASTERN EUROPE; HUNGARY

Accession no.476073 Item 236 International Seminar on Elastomers. Seminar Proceedings. Kurume, 7th-9th Oct.1990, p.295-307. 012 RUPTURE OF FILLER-LOADED RUBBER VULCANISATE Yamada E; Inagaki S; Okamoto H; Furukawa J Aichi, Institute of Technology Edited by: White J L; Murakami K (Akron, University; Teikyo, University) Applied Polymer Symposium 50 The effects of vulcanisation on the elasticity and strength of rubber are considered in terms of both chemical and pseudocrosslinks. The rupture of rubber vulcanisates is examined, using, as a basis, the theory of failure of polymeric materials in association with the pseudocrosslink model. Rupture of rubber vulcanisates compounded with fillers, such as carbon black and

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calcium carbonate is discussed by extending the theory of rupture. 3 refs. JAPAN

Accession no.476069 Item 237 Eureka 13, No.3, March 1993, p.43/5 SOFTWARE MODELS SEAL’S FUTURE Barrett J To overcome present problems associated with the life prediction of seals, a collaborative research project was initiated at British Hydraulics Research Group. The scope of the research included the determination of basic parameters using test specimens; development of a computer program to apply these results to actual seals; and performance tests on 500 seals under controlled conditions. In addition, a Seal Life Prediction Methodology is being compiled for a predictive tool for use in the assessment of the suitability of elastomers for particular applications. Details are given. BRITISH HYDRAULICS RESEARCH GROUP EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.474168 Item 238 Polymers in Extreme Environments. Conference Proceedings. Nottingham, 9th-10th July 1991, Paper 20. 93 SEALING IN EXTREME ENVIRONMENTS De Silva R; Eastwood B G Greene, Tweed & Co.Ltd. (PRI) An overview is presented of the design processes required to address industry’s need to provide long-term integrity sealing in extremes of temperature, pressure and chemical environments. Examples drawn from the offshore oil and gas market are used to illustrate the consideration of explosive decompression and fluid attack to elastomers. Examples are also used to illustrate various modes of failure in conventional seal types. The way in which newly developed perfluoroelastomers has brought significant performance improvements in biomedical, pharmaceutical and semi-conductor industries is demonstrated. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.474125 Item 239 Polymers in Extreme Environments. Conference Proceedings. Nottingham, 9th-10th July 1991, Paper 19. 93 BEHAVIOUR OF ELASTOMERS UNDER HIGH PRESSURE CONDITIONS Seregely Z I Taurus Hungarian Rubber Works (PRI)

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The results are reported of a study of the effects of gaseous oil, gaseous sour oil, oily gas and dry gas at different temperatures and pressures on several elastomers. These elastomers were CR, NBR, hydrogenated NBR, FKM and EPDM. 13 refs. EASTERN EUROPE; HUNGARY

Accession no.474122 Item 240 Polymers in Extreme Environments. Conference Proceedings. Nottingham, 9th-10th July 1991, Paper 18. 93 DURABILITY OF TFE/P AND OTHER FLUORINATED ELASTOMERS EMPLOYED FOR SEALING PURPOSES IN HOSTILE ENVIRONMENTS AT HIGH PRESSURES Abrams P I; Campion R P Exxon Production Research Co.; Materials Engineering Research Laboratory Ltd. (PRI) It is possible for elastomers based on tetrafluoroethylenepropylene copolymer, when used for sealing purposes, to withstand extreme conditions of temperature, pressure and environment, provided that design of material recipe and housing geometry, etc. is optimised. If reductions in mechanical properties occur during exposure to extreme environments, they are much more likely to happen as a result of physical attack by fluids rather than chemical attack. A theoretical background is provided and data from laboratory experiments on liquid uptake, high pressure gas permeation and explosive decompression measurements are used to support the above conclusions. 10 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.474121 Item 241 Polymers in Extreme Environments. Conference Proceedings. Nottingham, 9th-10th July 1991, Paper 3. 93 DELETERIOUS EFFECTS OF ATMOSPHERIC ENVIRONMENTS ON RUBBER-RUBBER ADHESION Corish P J Corish P.J., & Associates (PRI) The effects of ozone, UV irradiation and sunlight on the peel adhesion of NR-based compounds were investigated and methods of preventing and/or overcoming poor interfacial adhesion evaluated. These methods included simple protection of the rubber surface, compounding variations, use of particulate-type adhesives and solvent scrubbing of the rubber surfaces. 7 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.474106

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References and Abstracts

Item 242 Kautchuk und Gummi Kunststoffe 44, No.11, Nov.1991, p.1029-32 ASPECTS OF ELASTOMER PRODUCT ANALYSIS IN INDUSTRIAL TROUBLESHOOTING Loadman M J R Malaysian Rubber Producers’ Research Assn.

Item 245 Gummibereifung 68, No.7, July 1992, p.74/80 German TO HAVE CONFIDENCE IS GOOD, BUT TUV CONTROL IS BETTER After a survey of the problem of scrap tyres in Germany, a description is given of AIR and TUV Bayern’s quality assurance system for retreading tyres. This involves testing the carcass as well as the various stages of the retreading process. The increased cost is justified by the classification of the retreads in the 160-190 km/h range and the consequent improved reputation of the product. A.I.R.; REIFEN IHLE GMBH; REST GMBH; REIFF GMBH; REIFEN SCHWARZ; VERGOELST GMBH; TUV BAYERN; BUV

Product analysis is an essential part of industrial troubleshooting which enables the reasons for a product failure to be understood and explained to the end user. For a number of years, analytical procedures have been developed at the Malaysian Rubber Producers’ Research Assn. in answer to specific problems experienced by rubber product manufacturers. This paper discusses some of the less common techniques, or novel uses of established techniques in the context of real-life problem solving.

EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.470947

Accession no.472504 Item 243 Kautchuk und Gummi Kunststoffe 44, No.7, July 1991, p.659-62 German PREDICTION OF THE FATIGUE-LIFE OF RUBBER-METAL PARTS BY USE OF FEM Caspers M; Barth T; Schenk R Freudenberg Carl Experimental test results and theoretical calculations were used together to predict the fatigue life of rubber-metal components. The goal was to achieve design rules based on stress cycle curves. Design curves for different failure criteria were evaluated to predict the fatigue life for an automotive clutch, consisting of a NR compound. Various failure criteria were compared and discussed. For two of the criteria, the agreement between the predictions and the fatigue tests was very good. EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.472448 Item 244 International Polymer Science and Technology 19, No.11, 1993, p.T/43-6 RELIABILITY OF AIRCRAFT TYRES WITH MAXIMUM PERMISSIBLE MECHANICAL DAMAGE Gitmeier L I; Titov V S; Moskalenko V N Up to 40% of all aircraft tyres have to be taken out of service on account of mechanical damage. Up to now there has been practically no analysis of the effectiveness and level of reliability of tyres with widened tolerances in respect of mechanical damage, and this has led to a study of the fatigue life and service life and service reliability of such tyres, leading to considerable financial savings. 4 refs.Translation of Kauch.i Rezina, No.4, 1992, p.12 RUSSIA

Accession no.472387

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Item 246 Kautchuk und Gummi Kunststoffe 45, No.4, April 1992, p.296-323 German MANUFACTURING OF RUBBER MOULDINGS ORIENTED TO QUALITIES: MATERIALMOULDING-PROCESS Gernot T; Harms R; Kretzschmar G; Sunder J Institut fuer Kunststoffverarbeitung Two kneader control units, for the manufacture of rubber mouldings to tight tolerances are discussed. The viscosity control concept smooths out fluctuations in raw materials, particularly in the case of NR. The viscosity can be kept within tight tolerances by this system. The second concept increases reproducibility by controlling the movements of the floating weight. A new numerical process is presented which describes the effect of the chemical processes involved in processing crosslinking moulding compounds on the heat balance in the moulded part. Heating times can thus be established precisely and thermal relationships in the mould can be optimised. The CAD-MOULD-3D program system and the MESTRO-E stream line module are described, which supply data for injection mould layout in rheological and thermal terms and for allowance for the reaction kinetics of the moulding compound. Finally, an approach is presented which allows statements to be made on the quality of moulded parts at the production stage. 69 refs. EUROPEAN COMMUNITY; GERMANY; WESTERN EUROPE

Accession no.470931 Item 247 Kautchuk und Gummi Kunststoffe 45, No.4, April 1992, p.288-94 German EFFECT OF STORAGE CONDITIONS AND STABILISATION OF RAW RUBBER AND ITS

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PROCESSING BEHAVIOUR ON THE PROPERTIES OF UNCURED AND CURED COMPOUNDS Knobloch G Ciba-Geigy AG The effect of simulated warehouse ageing on stability during subsequent processing and compounding was examined in low-cis polybutadiene and solution polymerised SBR. The elastomers were aged in recirculating air ovens at 70C and changes of Mooney viscosity (MV) and gel content were evaluated. Samples were further evaluated using short-term, hightemperature test conditions and torque/time plots were recorded. The torque/time plot may change dramatically, though the elastomer used for compounding had an unchanged MV. The resulting compound was, thus, of low homogeneity leading to a low quality vulcanisate, or it was even unserviceable. Antioxidant addition during compounding could not prevent the damage. MV change or gel content after low temperature storage does not always correlate with high temperature processing stability after storage. Predamage due to storage conditions can be minimised by using suitable antioxidants for the elastomers. 2 refs.

Item 249 Journal of Natural Rubber Research 7, No.3, 1992, p.195-205 MICROBIAL DEGRADATION OF NATURAL RUBBER Low F C; Tan A M; John C K Until recently, most reports of biodegradation of NR had been on vulcanised rubber and rubber products. The microbial degradation of raw and purified rubber from Hevea brasiliensis Muell Arg. by several microorganisms is described. The degradation was accompanied by an increase in pH of the medium and a decrease in the rubber, nitrogen and protein contents. Screening of micro-organisms capable of utilising NR for growth is carried out by incubating each test organism in (1:10, 000) diluted sterile latex, followed by assessment on the ability of the organism to clear the milky rubber solution. 32 refs. RUBBER RESEARCH INSTITUTE OF MALAYSIA MALAYSIA

Accession no.470120

Accession no.470930

Item 250 Tyres & Accessories No.1, 1993, p.88/90 RUBBER ON THE ROAD - TRL STUDY

Item 248 Journal of Biomedical Materials Research 27, No.3, March 1993, p.345-56 DEGRADATION OF MEDICAL-GRADE POLYURETHANE ELASTOMERS: EFFECT OF HYDROGEN PEROXIDE IN VITRO Meijs G F; McCarthy S J; Rizzardo E; Chen Y C; Chatelier R C; Brandwood A; Schindhelm K CSIRO; New South Wales, University

The Transport Research Laboratory is reported to have recently carried out an investigation into the incidence of tyre debris on the M4 motorway. The Department of Transport says that it receives correspondence from the general public concerning tyre debris and many are firmly of the opinion that the rubber littering roads comes from retreads. Details of a study commissioned to discover the origins of tyre debris are presented. UK, TRANSPORT RESEARCH LABORATORY

SWITZERLAND; WESTERN EUROPE

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Treatment of Pellethane 2363-80A, a medical-grade poly(tetramethylene oxide)-based PU elastomer, with 25% (w/w) hydrogen peroxide at 100C for times ranging from 24 h to 336 h was shown to lead to significant decreases in ultimate tensile properties and decreases in molec.wt., both at the surface and in the bulk. IR spectral changes were similar to those observed after degradation in vivo. DSC showed that hydrogen peroxide-induced degradation was associated with greater order in the hard domain and greater mobility in the soft domain. Studies conducted with low molec.wt. model compounds for the hard and soft segments confirmed that methylene groups adjacent to oxygen were susceptible towards oxidation. The extent of degradation of a series of commercial PUs on treatment with hydrogen peroxide (25%, 24 h, 100C) correlated well with their reported susceptibility to environmental stress cracking in vivo. 38 refs.

Accession no.467981 Item 251 Asia-Pacific Chemicals 3, No.5, Oct.1992, p.20-1 PERFLUOROCARBONS OFFER THE SEAL OF SUCCESS This comprehensive article highlights to problems that occur due to failure of pump seals and valve seats and the consequent costs to the plant operators. The article highlights particularly Kalrez perfluoroelastomer from Du Pont, which combines chemical resistance and resilience and so extends the use of elastomers into areas where rubbers had previously failed. The article supplies full details of the material and its properties. DU PONT DE NEMOURS GMBH

AUSTRALIA

EUROPEAN COMMUNITY; NETHERLANDS; WESTERN EUROPE

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Item 252 142nd Meeting, Fall 1992, Conference Proceedings. Nashville, Tn., 3rd-6th Nov.1992, Paper 79, pp.33. 012 EFFECT OF STORAGE CONDITIONS AND STABILISATION OF RAW RUBBER ON ITS PROCESSING BEHAVIOUR AND ON THE PROPERTIES OF UNCURED AND CURED COMPOUNDS Earhart N J; Thomas R W; Vrudny F Ciba-Geigy Corp. (ACS, Rubber Div.) Samples of raw SBR and polybutadiene heat aged to simulate extended storage were examined to determine whether storage-induced damage is inflicted on rubber which cannot be identified by specification data such as Mooney viscosity and gel content, and which may change processing behaviour and the properties and quality of compounds and vulcanisates. Such damage could be identified through processing-analogous high temperature exposure in silicone oil ageing or hot shearing tests. The occurrence of the critical pre-damage conditions could be avoided, or at least delayed, by the use of stabilisers prior to storage. Addition of anti-ageing agents during mixing could not correct changes already caused by predamage. 2 refs. USA

Accession no.465609 Item 253 Plastics and Rubber International 17, No.4, Aug/Sept.1992, p.8-9 OXIDATION PROFILING METHODS: THE HARWELL EXPERIENCE Nelson K; Hepburn C AEA Technology; Ulster, University Oxidation profiling techniques and methods of predicting the behaviour of rubber under complex operating conditions are described with the object of predicting service life of rubber components. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.463437 Item 254 Rubber World 207, No.1, Oct.1992, p.16-7 TROUBLE-SHOOTING O-RING FAILURES Hawkes S Apple Rubber Products Inc. This comprehensive article describes the use of o-rings and the mechanical and chemical causes of failure of an o-ring seal. The article also set out a number of seal failure prevention strategies, including visual inspection, o-ring sizing and material selection. 6 refs. USA

Accession no.463116

© Copyright 2002 Rapra Technology Limited

Item 255 Rubber India 44, No.8, Aug.1992, p.23-6 NEED OF QUALITY CONTROL SYSTEM FOR CELLULAR PRODUCTS The technology to manufacture sponge or expanded rubber is not so critical, but long retention of product quality is very difficult, unless a strict process control system is adopted. This paper highlights a process control system to be followed at all stages in production of expanded rubbers. INDIA

Accession no.461855 Item 256 Journal of Materials Science 27, No.13, 1st July 1992, p.3424-34 WATER ABSORPTION, SWELLING, RUPTURE AND SALT RELEASE IN SALT-SILICONE RUBBER COMPOUNDS Schirrer R;Thepin P;Torres G ICS(CRM-EAHP); RHONE-POULENC SA The study revealed that water vapour diffused rapidly in silicone rubber and that in a PDMS-salt compound surrounded by water, the water that entered the rubber was absorbed by the salt particles, creating an osmotic pressure in the rubber. This pressure gave rise to internal cracks in the rubber, which eventually percolated and resulted in a salt exchange between the rubber-salt compound and the surrounding pure water. Equations describing the onset and propagation of the microcracks in the silicone were derived as a function of rubber fracture toughness, tensile modulus and osmotic pressure of the salt. 22 refs. EUROPEAN COMMUNITY; FRANCE; WESTERN EUROPE

Accession no.461434 Item 257 Journal of Natural Rubber Research 7, No.1, 1992, p.1-13 OZONE CRACKING AND PROTECTION OF ELASTOMERS AT HIGH AND LOW TEMPERATURES Lake G J;Mente P G MALAYSIAN RUBBER PRODUCERS’ RESEARCH ASSN. A study was made of ozone attack on several elastomers (NR, epoxidised NR and two nitrile rubbers) varying in their Tgs by about 50C over a range of temps from -20C to +70C. Varying protective systems were employed, including chemical antiozonants or waxes alone and wax/ antiozonant combinations. It was found that if the ambient temp. was low, the rate of crack growth due to ozone may be reduced by the high internal viscosity of the material. However, diffusion of chemical antiozonants or waxes

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which confer protection by forming a layer on the rubber surface, may also be slowed down. 11 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.461335 Item 258 Contraception 46, No.3, Sept.1992, p.279-88 STUDY TO DETERMINE THE CORRELATION BETWEEN CONDOM BREAKAGE IN HUMAN USE AND LABORATORY TEST RESULTS Steiner M;Foldesy R;Cole D;Carter E FAMILY HEALTH INTERNATIONAL The value of laboratory tests in predicting condom breakage was examined for twenty lots of latex condoms which differed in age, storage history and laboratory test performance. The statistical predictor models, separately using ultimate elongation from the tensile test, the Condom Quality Index from the airburst volume test, and the percent of condoms failing the airburst volume test as the independent variables and the condom breakage rate as the dependent variable, all appeared to have a high level of accuracy in predicting condom breakage in use. 16 refs.

discussed. With current legislation, the user of such equipment is urged to limit the amount of VOCs and VHAPs released, and designers are shown to have to meet or exceed the legislative pressure which will eventually be instated. The selection of an appropriate seal design, material and construction is facilitated by selection guidelines offered and which have been established by the WG-3 Emissions Work Group. Details are included on the basic seal technology with regard to the specific gravity of the fluid being sealed, and the emission level requirements. USA

Accession no.459712 Item 261 International Polymer Science and Technology 19, No.4, 1992, p.T/41-56 SELECTING DAMPING MATERIALS (SERVICE ENVIRONMENT, STRAIN AND ENDURANCE) Yamashita S Full translation of Nippon Gomu Kyokaishi, No.12, p.752. 74 refs. JAPAN

Accession no.459648

USA

Accession no.461125 Item 259 Journal of Natural Rubber Research 7, No.1, 1992, p.14-37 PROPERTIES OF RUBBER COMPOUNDS FOR ENGINEERING APPLICATIONS Muhr A H MALAYSIAN RUBBER PRODUCERS’ RESEARCH ASSN. The relationship between the properties of rubber and the performance of the resulting engineering component is discussed in depth. Consideration is given to stress strain behaviour (quasi-static force-deformation behaviour of mounts, dynamic stiffness and dynamic to static ratio, damping, creep and stress relaxation), environmental effects (swelling by oils, oxidation, ozone attack, hysteretic heating/heat build-up and the effects of water and temp.) and mechanical failure (crack propagation, fatigue and cavitation. 41 refs. MALAYSIA

Item 262 Polymer Preprints. 32, No.1, April 1991, p.648-9 IMAGING OF AUTOXIDATION INDUCED CHEMILUMINESCENCE Fleming R H;Craig A Y EVANS C., & ASSOCIATES The chemiluminescence imaging equipment developed by Charles Evans & Associates is described and an example is given of the ageing-induced image obtained from a sample of hydroxy-terminated polybutadiene cured with isophorone diisocyanate (a material used as a binder in solid fuel rocket motors). It is demonstrated that the sites of material failures and possibly the sites of incipient failures can be located and studied using chemiluminescence imaging. 1 ref. (ACS, Div of Polymer Chemistry, Atlanta, Georgia, April 1991) USA

Accession no.458857

Item 260 Eureka 12, No.7, July 1992, p.37/9 DESIGNING FOR ZERO LEAKAGE Barrett J

Item 263 Rubber Chemistry and Technology 65, No.2, May-June 1992, p.350-73 INTERNAL CRACK SYMMETRY PHENOMENA DURING GAS-INDUCED RUPTURE OF ELASTOMERS Briscoe B J;Liatsis D LONDON, UNIVERSITY, IMPERIAL COLLEGE

The use of rotating mechanical seals to prevent leakage from rotating machinery such as pumps and valves is

An experimental and analytical investigation was conducted of the consequences of removing a high

Accession no.460910

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References and Abstracts

ambient gas pressure environment from a number of elastomers after they had been allowed to equilibrate under high gas pressure. The elastomers were shown to be irreversibly damaged and the phenomenology of this damage was examined. One particular type of damage, the formation of internal symmetrical cracks whose geometry was the same as that of the sample, was studied in detail and the experimental data were interpreted using two models. It was suggested that ruptures arose as a result of the combined effects of an overall hydrostatic tension and a localised tensile field which was created by the effusion of gas from the polymer. The severity of the latter was shown to be a function of the gas transport properties of the elastomer under the conditions which prevailed during the gas desorption process. 22 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.457692 Item 264 International Journal of Adhesion & Adhesives 12, No.2, April 1992, p.111-6 SCANNING AND ENVIRONMENTAL ELECTRON MICROSCOPY STUDIES OF SILICONE RELEASE COATINGS Stein J;Bolon R B;Porta M L;Robertson C D;Grenoble ME GE SILICONES; GENERAL ELECTRIC CO., RES.& DEV.CENTER SEM and environmental SEM were used to characterise silicone release coatings on a variety of paper substrates exhibiting different release values. A sectioning procedure was developed to measure coating thickness and penetration data. A 180 degree peel sub-stage was constructed for environmental SEM and used to observe and record the microdeformation occurring at the parting interface. The results of this study showed that the applied coating flowed to fill in depressions on rough substrates, leaving thin, easily damaged layers on the high areas after cure. Such defect sites changed the peel mechanism. 7 refs. USA

Accession no.457492 Item 265 Rubber and Plastics News 2 13, No.12, 6th April 1992, p.2 COURT DELAYS CASE AGAINST RUBBER CRAFTERS Moore M This article provides a detailed account of charges laid against Rubber Crafters Inc. It is alleged that the company knowingly supplied the US Navy with defective MK-6 rubber lifeboats. The trial has been postponed pending the outcome of a related case involving one of the defendants . Of 500 boats supplied by the company, and tested by the Navy for possible defects, 82.5% failed automatically.

© Copyright 2002 Rapra Technology Limited

RUBBER CRAFTERS INC. USA

Accession no.455981 Item 266 141st Meeting, Spring 1992, Conference Proceedings. Louisville, Ky., 19th-22nd May 1992, Paper 73, pp.15. 012 ELECTROCHEMICAL DEGRADATION OF COOLANT HOSES Schneider H;Tucker H;Seo E T GATES RUBBER CO. (ACS, Rubber Div.) A report is presented of research undertaken by Gates Rubber Co. into the causes of coolant hose failure, which shows that the primary cause of almost all such failures is an electrochemical attack on the tube compound, leading to cracks, leaks or rupture of the hose. In vehicle applications, the engine and radiator fittings act as the anode, the liquid coolant as the electrolyte, and the hose (containing oxygen) as the positive electrode. Heat accelerates the degradation reaction, but compounding for maximum heat resistance in the traditional sense does not improve electrochemical resistance, and can in fact make it worse. USA

Accession no.453101 Item 267 141st Meeting, Spring 1992, Conference Proceedings. Louisville, Ky., 19th-22nd May 1992, Paper 56, pp.18. 012 FATIGUE BEHAVIOUR OF CORDREINFORCED RUBBER COMPOSITES Borowczak M;Causa A G GOODYEAR TIRE & RUBBER CO. (ACS, Rubber Div.) The use of fracture mechanics in the study of fatigue failure in cord-reinforced rubber composites is discussed, with reference to the findings of some published studies. 9 refs. USA

Accession no.452961 Item 268 140th Meeting, Fall 1991, Conference Proceedings. Detroit, Mi., 8th-11th Oct.1991, Paper 17, pp.39. 012 RELATING THE PROPERTIES OF POLAR AND NON-POLAR LIQUIDS TO THE SWELLING OF NITRILE RUBBER VULCANISATES BY THESE LIQUIDS. II. SWELLING CURVES Starmer P H ZEON CHEMICALS USA INC. (ACS, Rubber Div.) A study was made to determine whether any of the parameters describing the polarity of liquids relate to the swelling of nitrile rubber vulcanisates. A Gaussian curve

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was obtained to describe the swelling, by various liquids, of a series of rubbers containing from 0 to 50% bound acrylonitrile. The only parameter having a good correlation was the polarity index obtained by liquid chromatography. 26 refs. USA

Accession no.452494 Item 269 140th Meeting, Fall 1991, Conference Proceedings. Detroit, Mi., 8th-11th Oct.1991, Paper 12, pp.7. 012 APPLICATION OF MECHANICAL TESTING AND SPECTROSCOPY IN SOLVING ROOFING PROBLEMS Paroli R M;Dutt O;Lavallee C CANADA, NATIONAL RESEARCH COUNCIL (ACS, Rubber Div.) Fourier transform IR spectroscopy, SEM, energy dispersive X-ray spectroscopy and tensile testing were used to characterise a fully adhered EPDM roofing membrane which had exhibited surface degradation in the form of brownish staining and subsequent failure. The results suggested that the cause of the staining and failure could be attributed to the rubberised asphalt adhesive. 6 refs. CANADA; USA

Accession no.452341 Item 270 British Plastics and Rubber No.3, March 1992, p.23 PLANNING FOR WHAT COULD GO WRONG CAN STOP PROBLEMS BEFORE THEY START The Halesowen Microcentre’s FMEA (Failure Mode and Effect Analysis) software provides a logical methodology to determine all possible ways in which a part or assembly might fail to meet its specifications. Possible failure modes are then analysed according to effect on customer, seriousness of this, potential cause of failure and its likely frequency, and the probability that it will be detected by existing quality checks. The FMEA information is then transferred to a control plan, which is generated by the software, and which sets out how checks are to be implemented. HALESOWEN MICROCENTRE

The contact angle properties of latex condoms were investigated under various conditions, including neutral and acidic solutions, hot and old water and bovine serum, and the relationship between these properties and the sensitivity of various water leakage tests examined. The results obtained indicated that the biological environments encountered upon actual use are likely to promote leakage and that by using a surfactant solution instead of water to fill the condom, the sensitivity of the leakage test could be improved. 19 refs. USA

Accession no.443297 Item 272 International Rubber Conference:Communications.Conference Proceedings. Paris, 12th-14th June 1990, p.347-9. 012 BEHAVIOUR OF RUBBER VULCANISATES UNDER HIGH PRESSURE GAS CONDITIONS (INCLUDING EXPLOSIVE DECOMPRESSION) Seregely Z I TAURUS HUNGARIAN RUBBER WORKS (AFICEP) Factors involved in failure mechanisms in elastomers (particularly hydrogenated NBR) subjected to gas exposures at high pressures and at various temps. are discussed. The prediction of the behaviour of rubbers under gas service is considered. EASTERN EUROPE; HUNGARY

Accession no.441598 Item 273 International Rubber Conference:Communications.Conference Proceedings. Paris, 12th-14th June 1990, p.81-2. 012 FOURIER TRANSFORM IR INVESTIGATIONS OF THE DEGRADATION OF UNSATURATED POLYMERS IN REACTIVE GASES Vogel L;Gross D BUNDESANSTALT FUER MATERIALFORSCHUNG & -PRUEFUNG (AFICEP) A brief report is presented on studies of the ozonolysis of unsaturated rubbers, e.g. NR and chloroprene rubber, carried out by means of FTIR spectroscopy.

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

GERMANY

Accession no.446320

Accession no.441544

Item 271 Journal of Testing & Evaluation 18, No.5, Sept.1990, p.352-8 INFLUENCE OF CONTACT ANGLE ON THE LEAKAGE OF LATEX CONDOMS Davis G ;Schroeder L W US, FOOD & DRUG ADMINISTRATION

Item 274 International Rubber Conference:Communications.Conference Proceedings. Paris, 12th-14th June 1990, p.286-7. 012 HOMOGENEITY OF THE SURFACE OF A PRODUCT MADE BY EXTRUSION STRIP WINDING

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Laurila T FINLAND, RUBBER TECHNOLOGY ASSOCIATION (AFICEP) Results are presented of studies, carried out using a cavity transfer mixer, of means of avoiding the defect of extruder marking in extrusion strip winding of large rubber articles. FINLAND; SCANDINAVIA; WESTERN EUROPE

Accession no.441406 Item 275 Tire Business 9, No.15, 4th Nov.1991, p.5 TYRE INFLATORS CAUSING INJURIES, DESPITE WARNINGS Mikolajczyk S J An explosion occurred during the repair of a tyre which had previously been inflated using a sealant-type tyre inflator. The result of the ensuing legal action is reported, together with summaries of other similar explosions/fires, collated by the victim’s lawyer. The volatility threshold appears to be reached at very low concentrations. USA

Accession no.437185 Item 276 Elastomerics 123-No.11, Nov.1991, p.9-10 RAPRA MEETING EXAMINES THE FUTURE OF ELASTOMERS IN OIL FIELD APPLICATIONS Bowtell M Challenges and potential solutions associated with elastomeric components inoil field applications was the topic of a recent conference sponsored by Rapra Technology. The conference reviewed such subjects as developments in materials, product evaluation, installation and maintenance, as well as specific challenges associated with aggressive environments and explosive decompression. RAPRA TECHNOLOGY LTD. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.437159 Item 277 138th Meeting Fall 1990.Preprints. Washington, DC, 9th-12th Oct.1990, Paper 51. 012 INVESTIGATION OF RUBBER/METAL BOND FAILURES BY SURFACE ANALYSIS TECHNIQUES Madura A R LORD CORP. (ACS, Rubber Div.) Various types of failures encountered in rubber/metal bonding are illustrated to demonstrate the potential effects

© Copyright 2002 Rapra Technology Limited

of extraneous contamination, specifically silicone material, on bonding properties. The effectiveness of multiple surface analysis techniques are demonstrated for the detailed evaluation of bond failures. Reference is made to SEM, energy dispersive X-ray spectrometry, X-ray photoelectron spectrometry, secondary ion mass spectrometry and ion scattering spectrometry. Bond testing by peel strength was used. 12 refs. USA

Accession no.436720 Item 278 138th Meeting Fall 1990.Preprints. Washington, DC, 9th-12th Oct.1990, Paper 69. 012 INITIATION OF VOIDS IN REINFORCED RUBBER FABRIC BY MECHANICAL FLEXURE Nagode J B;Poranski C F;Greenawald E C GEO-CENTERS INC.; US, NAVAL RESEARCH LABORATORY (ACS, Rubber Div.) Static wick test results on a ‘wickproof’ steel cord reinforced neoprene rubber fabric for sonar dome rubber windows (SDRWs) on US navy vessels are presented. A dynamic water wicking test was developed to model actual operating conditions of the SDRWs. All fabric samples believed to be wickproof failed this test. The effects of mechanical flexure on other mechanical properties of steel reinforced rubber fabric are discussed. 11 refs. USA

Accession no.436073 Item 279 138th Meeting Fall 1990.Preprints. Washington, DC, 9th-12th Oct.1990, Paper 46. 012 EFFECTS OF EXTRACTING HYDROLYTIC STABILISERS ON URETHANE PERFORMANCE Feuer H O;Touchet P BELVOIR RESEARCH DEVELOPMENT & ENGNG.CENTER; RUBBER & COATED FABRICS RESEARCH GROUP (ACS, Rubber Div.) Results of tests are reported to prove that collapsible fuel tank failures are due to diesel fuel extracting out the protective ingredients in the PU elastomer coatings, in particular, the hydrolytic stabiliser, aromatic polycarbodiimide. The elastomer’s degradation was monitored by the degree of deterioration of physical properties. USA

Accession no.436025 Item 280 Rubber Southern Africa 7, No.2, Sept/Oct.1991, p.8 HEAT SHORTENS TYRE LIFE-BANDAG STUDY

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A study has been carried out by Bandag on the effects of precured retread curing temperatures on truck tyre life. The company claims that tyres cured at 100 ∞C averaged about a 30 to 35% longer life on the road wheel. Retreaders attending the ARA show in April protested that releasing the test information would be damaging to the retread industry and specifically to those using the higher cure temperatures. BANDAG INC.

SHOOTING Loadman M J R MALAYSIAN RUBBER PRODUCERS’ RESEARCH ASSN. (Deutsche Kautschuk Ges.) Long abstract only. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.435043

USA

Accession no.435337 Item 281 Elastomers in Oil Recovery.Seminar Proceedings. Manchester, 9th Sept.1991, Paper 4. 63Pet HOSE FAILURES: DESIGN, MANUFACTURE OR SERVICE CONDITIONS Hindmarch R S RAPRA TECHNOLOGY LTD. (Rapra Technology Ltd.) Causes of failure on many different hoses over a 15 year period are investigated. Each examination was treated as part of a continuing study so that fundamental modes of failure could be identified, and dealt with at a design, manufacturing or in-service stage. Attempts were made to identify non-destructive in-service monitoring to ascertain length of service limits. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.435320 Item 282 Elastomers in Oil Recovery.Seminar Proceedings. Manchester, 9th Sept.1991, Paper 1. 63Pet EVALUATION OF HNBR IN SEVERE OILFIELD ENVIRONMENTS Moore J;Ridland J POLYSAR RUBBER CORP. (Rapra Technology Ltd.) Two demanding environments are considered; explosive decompression and hydrogen sulphide exposure. A brief review of previous data is given for the former, comparing different polymer types. An attempt is also made to establish a compounding baseline to optimise HNBR performance by examining formulation variables and their effects. For the latter, a comparison of HNBR with NBR, FKM fluoroelastomer and TFE/P is made, as well as a brief look at the effect of ACN (acrylonitrile) content on performance. 4 refs. CANADA

Accession no.435266

Item 284 Shawbury, 1991, 8 Papers. LS.50. 12ins. 5/11/91. 63Pet ELASTOMERS IN OIL RECOVERY. PROCEEDINGS OF A SEMINAR HELD MANCHESTER, 9TH SEPT.1991 RAPRA TECHNOLOGY LTD. Eight papers, presented at this one-day seminar, are published examining aspects of elastomer component use in the oil recovery industry. Topics under discussion include an evaluation of HNBR in severe oilfield environments; hose failure and the implications for design, manufacture and service conditions; elastomeric seal life prediction; and polymer coated fabrics in the oil industry. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.434499 Item 285 Journal of Rheology 35, No.6, Aug.1991, p.985-98 SHARKSKIN DEFECTS OF POLYMER MELTS: ROLE OF COHESION AND ADHESION Tremblay B CANADA, INDUSTRIAL MATERIALS RESEARCH INSTITUTE An explanation is given for the surface defect, commonly referred to as sharkskin, which occurs at the die exit. Using a simulation of the flow of a linear polydimethylsiloxane melt, which showed significant sharkskin, through a capillary, it is shown numerically that large negative pressures can exist at the die exit. Furthermore, a series of photographs indicates that the cracks on the surface of the extrudate originate at the die exit and not further down the extrudate. It is postulated that negative pressure cavitates the polymer melt very close to the die lip at the die exit on the surface of the die or in the bulk of the polymer, depending on the respective strengths of adhesion to the die surface at the exit or of the cohesion of the bulk of the polymer. The growth or coalescence of these voids would then lead to cracks (sharkskin) at the die exit. 19 refs. CANADA

Item 283 International Rubber Conference.Summaries. Essen, 24th-27th June 1991, p.127-8. 012 ASPECTS OF ELASTOMER PRODUCT ANALYSIS IN INDUSTRIAL TROUBLE-

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Accession no.433843 Item 286 Tire Business 9, No.10, 26th Aug.1991, p.1/22

© Copyright 2002 Rapra Technology Limited

References and Abstracts

GROUPS FAULT 16-INCH TYRES IN DEATHS, INJURIES Slaybaugh C S An estimated 2000 to 3000 people have been killed over the last twenty years, when 16 inch tyres mounted on wrong sized rims, have exploded, after being inflated. Up to 30 million such tyres are said to have defective failure-prone beads. The hazard does not exist in every 16 inch tyre, but as many as three quarters of the 16 inch tyres currently on the road do not have fail-safe beads. This comprehensive article supplies the details. USA

Accession no.432136

Item 290 Cellular Polymers 9, No.3, 1990, p.206-28 EXPLOSIVE DECOMPRESSION IN ELASTOMERS. INTERNAL BLISTERING AND FRACTURING IN RUBBERS AFTER HIGH PRESSURE EXPOSURE TO GASES Campion R P MATERIALS ENGINEERING RESEARCH LABORATORY LTD. Factors and theory involved in the gas ingress and decompression stages occurring in rubbers exposed to gas at high pressures are discussed and the results of tests performed on several engineering elastomers (NBR, CR, chlorinated PE, FKM and a transparent cis-polyisoprene) are reported. Deviations from simple predictions and several forms of failure are shown and important parameters are identified, namely the solubility coefficient of the gas in the elastomer at the actual pressure and moduli and tearing energy of the elastomer. 14 refs.

Item 287 International Polymer Science and Technology 17, No.11, 1990, p.T/18-20 PREDICTING THE SERVICE PROPERTIES OF A VULCANISATE AND OF SEALING RUBBER COMPONENTS Yurtsev N N;Kuznetsova I A;Sedov V

EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Full translation of Kauch.i Rezina, No.4, 1990, p.23. 23 refs.

Accession no.427865

EASTERN EUROPE; USSR

Accession no.431542 Item 288 Deformation, Yield and Fracture of Polymers.Conference Proceedings. Cambridge, 8th-11th April 1991, p.116/1-116/5. 951 EFFECTS OF ATMOSPHERIC OXYGEN ON FRACTURE IN VULCANISED ELASTOMERS Lake G J Malaysian Rubber Producers’ Research Assn. (PRI) The influence of atmospheric oxygen on the fracture of NR vulcanisates subjected to tensile failure, creep and stress relaxation testing. It was found that the vulcanisates failed in a time-dependent manner at high stresses within the range 10 to 30 MPa. Such failure occurred under constant load or at constant deformation or could be revealed by a rate dependence of the strength in constant rate tests. The effects were attributed to the influence of atmospheric oxygen, which, following reaction, lowered the strength of the elastomer backbone chains. 12 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.430768 Item 289 International Polymer Science and Technology 17, No.10, 1990, p.T/16-7 DESIGN AND MONITORING OF RELIABILITY OF INDUSTRIAL RUBBER GOODS Karbasov O G Full translation of Kauch.i Rezina, No.4, 1990, p.21. 5 refs. EASTERN EUROPE; USSR

Accession no.428863

© Copyright 2002 Rapra Technology Limited

Item 291 International Seminar on Elastomers.Symposium Proceedings. Akron, Oh., 26th-28th Oct.1988, p.255-62. 012 BLOW-OUT OF RUBBER BLOCKS DUE TO INTERNAL HEATING Gent A N;Hindi M AKRON, UNIVERSITY Edited by: White J L;Murakami K (Akron, University;Tohoku, University) Applied Polymer Symposium 44 A study was made of blow-out of rubbers subjected to repeated compression, heated in a microwave oven or heated by passing an electric current through a copper wire embedded in the sample before vulcanisation. Blowout temps. for a range of rubbers (NR, SBR, BR, IIR and NBR) were determined and the possible nature of volatiles causing blow-out examined. 7 refs. USA

Accession no.426039 Item 292 Plastics Southern Africa 20, No.9, March 1991, p.32 STEAM TURBINES SEALED TIGHT WITH JOHN CRANE 28 An ethylene manufacturing plant had experienced bearing failure on a number of small steam turbines used to drive the cooling fans. The seals used on the turbines originally were of the floating carbon ring type, but leakage was a problem. A lower duty variant of the John Crane type 28 spiral-grooved dry gas seal was developed. A special grade of perfluoroelastomer O-rings was fitted to resist the high-

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pressure steam. Since their installation, the seals have operated without measurable leakage. CRANE J., INC. SOUTH AFRICA

Accession no.424978

(Paper given to the DKG Eastern Group, October 1990). Various aspects of quality control are discussed and an attempt made to assess what will be required in the future. 15 refs. BERGER R., & PARTNER GERMANY

Item 293 Tire Business 9, No.3, 20th May 1991, p.9 EXAMINE ROUTINE TYRE FAILURES TO AVERT LAWSUITS Ball C A Despite improved technology, the pneumatic tyre is said to remain a most unsatisfactory vehicle component: it can and will fail in the most inconvenient place at the most inconvenient time. The legal doctrine of strict liability is expanding, which means that an injured person may recover against the manufacturer or seller of a defective product, even though the manufacturer was not negligent and even though the injured party had no dealings with the manufacturer or the seller. USA

Accession no.423778 Item 294 China Rubber Industry 38, No.3, 1991, p.155-60 Chinese APPLICATION OF FINITE ELEMENT METHOD IN PNEUMATIC TYRE RESEARCH Xiaomei H;Lizhen C;Shouzhi L;Lijun X BEIJING, RESEARCH & DESIGN INST.OF RUBBER IND. Pneumatic tyre structure mechanics were analysed using non-linear finite element analysis. The deformation and stress-strain of all the components under inflation pressure of the tyre were predicted and the effects of three different bead structures on tyre performance were studied. It was found that stress concentration was the main cause of bead burst, separation and wear and that the tendency of the tyre to undergo early damage increased with decrease in bead rigidity. The study showed that the finite element method was an effective means of optimising tyre structure. 7 refs. CHINA

Accession no.423300 Item 295 Gummi Fasern Kunststoffe 44, No.4, April 1991, p.179-86 German QUALITY INCLUDED - QUALITY CONTROL UP TO 2000 AD Strothenk H CONTINENTAL AG

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Accession no.422683 Item 296 Polymers and Polymer Composites in Construction. London, Thomas Telford, 1990, p.183-203. 63ECi STRUCTURAL ELASTOMERIC BEARINGS AND RESILIENT SEATINGS Grootenhuis P IMPERIAL COLLEGE OF SCIENCE & TECHNOLOGY Edited by: Hollaway L C (Institution of Civil Engineers) Design considerations for supporting structures on rubber bearings are discussed as applied for isolation from ground borne vibration but excluding earthquakes. Subject headings are: trends in development and construction; human sensitivity to vibration; vibration damage of structures; basic facts of isolation; location of resilient bearings; selection and performance of elastomeric bearings; and, applications of composite construction for vibration isolation and movement control. 19 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.421273 Item 297 Building Sealants:Materials, Properties and Performance.ASTM STP 1069.Symposium Proceedings. Fort Lauderdale, Fl., 31st Jan-1st Feb.1990, p.122-40. 6A2 EXPERIMENTAL WORK CARRIED OUT IN SUPPORT OF THE DEVELOPMENT OF AN INTERNATIONAL STANDARD ON MOVEMENT CAPABILITY OF SEALANTS Wolf A T DOW CORNING EUROPE SA Edited by: O’Conner T F (American Society for Testing and Materials) ASTM STP 1069 The results of different laboratory tests, suggested during the development of an ISO standard on sealant durability, were compared with those obtained from outdoor weathering under mechanical strain. The comparison revealed that the 70C compression test, as included in ASTM C-719, was helpful in identifying sealants which fail due to high compression set. The heat compression test, however, did not rule out sealants that tend to postcure or embrittle upon ageing. The best correlation was obtained if the sealants were allowed to fully cure prior to laboratory testing. 6 refs.

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References and Abstracts

INTERNATIONAL STANDARDS ORGANISATION BELGIUM; EUROPEAN COMMUNITY; WESTERN EUROPE

Accession no.420317 Item 298 Building Sealants:Materials, Properties, and Performance.ASTM STP 1069.Symposium Proceedings. Fort Lauderdale, Fl., 31st Jan-1st Feb.1990, p.315-26. 6A2 WHY CONSTRUCTION SEALANTS FAIL - AN OVERVIEW Warseck K L BUILDING DIAGNOSTICS ASSOCIATES Edited by: O’Conner T F (American Society for Testing and Materials) ASTM STP 1069 An overview is presented of the reasons for construction sealants failing in the ‘real world’. These reasons are categorised by design errors, such as improper joints sizing, application errors, such as lack of surface preparation, and lastly material failures. 1 ref. USA

Accession no.420304 Item 299 Building Sealants:Materials, Properties, and Performance.ASTM STP 1069.Symposium Proceedings. Fort Lauderdale, Fl., 31st Jan-1st Feb.1990, p.303-14. 6A2 SEALANT USAGE FOR EXTERIOR INSULATION AND FINISH SYSTEMS Williams M F;Williams B L KENNEY/WILLIAMS/WILLIAMS INC. Edited by: O’Conner T F (American Society for Testing and Materials) ASTM STP 1069 General design, specification and application procedures for sealant joints on Exterior Insulation and Finish Systems are discussed with specific recommendations for avoiding sealant joint failure due to finish coat delamination. USA

Accession no.420303 Item 300 Adhesive Bonding. New York, Plenum Press, 1991, p.239-90. 9(12)4 DURABILITY EVALUATION OF ADHESIVE BONDED STRUCTURES Minford J D Edited by: Lee L H (Xerox Webster Research Center) The following topics are reviewed: chemical and physical attributes of adhesion and durability; failure site variabilities; bondline characteristics affecting bond

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performance; characteristics of metal adherend surfaces; effect of water on adhesive-bonded structures; bond-joint durability as a function of surface pretreatment; test environments for determining the durability of bonded structures; durability of structural joints assembled with combinations of joining procedures; and durability of dissimilar materials structures. 199 refs. USA

Accession no.419598 Item 301 Adhesive Bonding. New York, Plenum Press, 1991, p.139-73. 9(12)4 CHARACTERISATION OF SURFACES Davis G D MARTIN MARIETTA LABORATORIES Edited by: Lee L H (Xerox Webster Research Center) Surface-sensitive techniques for use in the study of adhesive bonding are discussed, including X-ray photoelectron spectroscopy and auger electron spectroscopy/scanning auger microscopy. Data analysis is considered, with reference to quantification, chemicalstate information, depth-distribution information and surface-behaviour diagrams. Applications to adhesive bonding are described, particularly failure analysis, hydration of phosphoric acid-anodised aluminium and adsorption of hydration inhibitors. 100 refs. USA

Accession no.419596 Item 302 12th International Conference on Fluid Sealing.Conference Proceedings. Brighton, 10th-12th May 1989, p.367-80. 6J REVIEW OF EXPERIENCES WITH MECHANICAL SEALS IN AN OPERATING REFINERY Roos E ESSO NEDERLAND BV (BHRA Fluid Engineering) Information gathered during two years of operation with newly designed and revamped mechanical seals is presented together with information concerning the use of the PF-value for troubleshooting and design, spare part quality statistics, installation requirements and pre-lapping of mechanical seal rings. Real field data is provided to support statements and conclusions. 7 refs. EUROPEAN COMMUNITY; NETHERLANDS; WESTERN EUROPE

Accession no.417896 Item 303 Rubber & Eastern Europe.Conference Proceedings. London, 21st Nov.1990, p.69-73. 17

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References and Abstracts

MAINTAINING QUALITY Russell-Fell R LRC PRODUCTS LTD. (Crain Communications Ltd.;First Europe Communications) The paper outlines ways of improving and maintaining Quality Standards in Eastern Europe, covering aspects such as production standards, raw materials and machinery, motivating the workforce, management skills, and testing and certification. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.417437 Item 304 Proceedings of the 31st Assembly of the IRSG.Vol.1. Bangkok, July 1989, 11 papers, pp.154. 17 QUALITY OF ELASTOMERS INTERNATIONAL RUBBER STUDY GROUP Eleven papers are presented on various economic aspects of the tyre industry and on the quality of elastomers. THAILAND

Accession no.417410 Item 305 London, 1986, pp.16. 12ins. 114-71 BS 5760:PART 0:1986. RELIABILITY OF CONSTRUCTED OR MANUFACTURED PRODUCTS, SYSTEMS, EQUIPMENT AND COMPONENTS. PART 0. INTRODUCTORY GUIDE TO RELIABILITY BRITISH STANDARDS INST. BSI.BS 5760:Part 0:1986 Aimed at directors of companies looking for overall advantages, engineers not trained in quality and reliability to show how reliability can help in their technical decision making and at middle management not specialised in engineering to demonstrate how reliability should be dovetailed in with other disciplines to give them the best result. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.417293 Item 306 Journal of Applied Polymer Science 41, No.5/6, 1990, p.1181-97 EFFECT OF COMPOUNDING INGREDIENTS ON MICROBIAL DEGRADATION OF VULCANISED NATURAL RUBBER Tsuchii A;Hayashi K;Hironiwa T;Matsunaka H;Takeda K JAPAN FERMENTATION RESEARCH INSTITUTE; JAPAN, CHEMICALS INSPECTION & TESTING INST. A series of natural rubber vulcanisates containing varied amounts of sulphur and accelerator (CBS) were prepared and their resistance to attack by a strain of Nocardia, capable of utilising natural rubber as carbon substrate,

80

was examined. The higher the content of sulphur or CBS, the less the wt. loss of the vulcanisates after microbial attack. In this system of curing without filler, the rate of microbial degradation was suggested to depend on the crosslink density estimated from the swelling. Addition of calcium carbonate as a filler did not affect the microbial degradation, and in some cases slightly enhanced it. Addition of carbon black, however, made the vulcanisate apparently more resistant to microbial attack, HAF grade carbon being more effective than SRF grade. 9 refs. JAPAN

Accession no.417184 Item 307 Philadelphia, Pa., 1990, pp.351. LS.43. 9ins. ASTM STP 1069. 18/3/91. 63Bu-6A1 BUILDING SEALANTS: MATERIALS, PROPERTIES, AND PERFORMANCE. PAPERS FROM A SYMPOSIUM HELD FORT LAUDERDALE, FL., 31ST JAN-1ST FEB.1990. O’Conner T F AMERICAN SOCIETY FOR TESTING AND MATERIALS ASTM STP 1069 Twenty-four papers are provided dealing with five areas of structural sealant concern - structural sealant glazing, movement capacity of sealants, laboratory investigation, sealant joint performance, and present and future trends. Particular aspects considered include European and U.S. testing procedures for structural glazing silicone sealants, sealant stresses in tension and shear, water resistance of sealants for construction, failure of construction sealants, and architectural design challenges for sealant technology and design standards. USA

Accession no.417013 Item 308 Tire Business 8, No.21, 11th Feb.1991, p.1/12 DESERT STORM TAKING TOLL ON VEHICLES’ TYRES Moore M According to several US government and industry sources, new and retreaded tyres have suffered premature failure in the punishing environment of Operation Desert Storm. All replacements for the failed tyres are said to have been new tyres purchased by the US Army’s Tank Automotive Command; details are given. US, ARMY USA

Accession no.416904 Item 309 Kautchuk und Gummi Kunststoffe 43, No.4, April 1990, p.321-6

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References and Abstracts

LIABILITY FOR DEFECTIVE PRODUCTS AND THE FRENCH LAW Faugerolas L

failure. The retreads have been replaced on the military vehicles with new tyres; details are given. AMERICAN RETREADERS ASSN.; US, ARMY

A discussion is presented on the rather complicated French legislation on product liability. 5 refs. (Second German French Rubber Symposium, Freiburg, Sept.1989).

IRAQ; MIDDLE EAST; SAUDI ARABIA; USA

EUROPEAN COMMUNITY; FRANCE; WESTERN EUROPE

Accession no.416608 Item 310 Kautchuk und Gummi Kunststoffe 43, No.4, April 1990, p.318-20 German LIABILITY FOR DEFECTIVE PRODUCTS AS DESCRIBED IN THE WEST GERMAN PRODUCT LIABILITY LAW Kreifels T ANWALTSSOZIETAET BRUCKHAUS KREIFELS WINKHAUS West German legislation on liability of producers, e.g. rubber and plastics manufacturers and processesors, for defective goods, is discussed with reference to a law introduced in January 1990. (Second German French Rubber Symposium, Freiburg, Sept.1989). EUROPEAN COMMUNITY; WEST GERMANY; WESTERN EUROPE

Accession no.416607 Item 311 136th Meeting, Fall 1989, Conference Proceedings. Detroit, Mi., 17th-20th Oct.1989, Paper 128. 012 UNIQUE APPROACH TO PRODUCT CHARACTERISATION AND RELEASE Forrest D D;Larson S F DU PONT DE NEMOURS E.I., & CO.INC. (ACS, Rubber Div.) A description is given of the technology used by Du Pont Elastomer Products for design and management of a statistically-based product release system. Release criteria and release decisions are based on the concept of statistically estimated ‘true values’ as opposed to observed values of products. An understanding of the nature of variability is regarded as being fundamental to quality management. 2 refs. USA

Accession no.415257 Item 312 Rubber and Plastics News 20, No.14, 21st Jan.1991, p.1/31 RETREADS PULLED FROM USE IN DESERT Moore M The US Army is reported to have withdrawn retreaded tyres from Persian Gulf operations, due to a high incidence of blowouts and retread separations caused by casing

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Accession no.414704 Item 313 Industria della Gomma 34, No.1-2, Jan-Feb.1990, p.29-32 Italian MEANING OF QUALITY ASSURANCE WITH RESPECT TO RUBBER PRODUCTS Bassi A C This article, which first appeared in the UNI journal for January 1990, covers production organisation; relevant European standards (Italian standards being closely modelled on BS 5750 (1979); company responsibilities and monitoring of raw materials. BSI; UNI EUROPE; EUROPEAN COMMUNITY; ITALY; UK; WESTERN EUROPE

Accession no.412795 Item 314 Tyre Industry Conference.Conference Proceedings. Greenville, SC, 25-26th Oct.1989, paper 8. 6T1 RUBBER ON THE ROAD - ITS NOT ALL FROM RETREADS Brodsky H TIRE RETREAD INFORMATION BUREAU (Clemson, University) A study has been carried out to discover where the scrap rubber on the roads comes from. It is claimed that a good portion of the rubber comes from new tyres and not retreads, and that practically all the rubber comes from truck tyres. The main reasons for this are overloading, incorrect tyre pressure and mismatching of dual tyres. USA

Accession no.411254 Item 315 Rubber Chemistry and Technology 63, No.3, July/Aug.1990, p.426-50 PROTECTION OF RUBBER AGAINST OZONE Layer R W;Lattimer R P GOODRICH B.F., CO. A review is presented of the literature on the protection of rubber against ozone. Particular attention is paid to the historical background, ozone formation, chemistry of the ozone-rubber reaction, physical requirements for ozone cracking, physical methods of ozone protection, chemical antiozonants, chemical antioxonants for polychloroprene, mechanism of action of chemical antiozonants, chemistry of the reaction of ozone and p-phenylenediamine, free-radical mechanism, and critical stress and antiozonants. 88 refs. USA

Accession no.409256

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References and Abstracts

Item 316 International Polymer Science and Technology 17, No.1, 1990, p.T/9-11 METHOD OF CALCULATING THE DURABILITY OF V-BELTS Chibisov V A;Dymnikov S I;Govodnichev Yu N;Gubanov V V

Item 320 Construction & Building Materials 3, No.3, Sept.1989, p.145-51 MOULD FUNGUS GROWTH ON SANITARY SEALANTS Wolf A DOW CORNING SA NV

4 refs. (Full translation of Kauch.i Rezina, No.8, 1989, p.31).

The requirements that must be satisfied by sanitary sealants are summarised, typical defects and their causes are described and mould fungus growth and attack on these sealants discussed in detail. Methods of combatting and preventing fungus attack are considered and procedures for testing the effectiveness of fungicides used in these sealants are examined. Finally, the results of Wallhaeuser tests on several commercially available sanitary silicone sealants, aimed at providing information on the probability of fungus attack, are reported. 15 refs.

EASTERN EUROPE; USSR

Accession no.407920 Item 317 International Polymer Science and Technology 17, No.1, 1990, p.T/6-8 DEFORMATION AND FAILURE OF CONVEYOR BELTS IN IMPACT Zuev Yu S;Shtern T M 8 refs. (Full translation of Kauch.i Rezina, No.8, 1989, p.23).

BELGIUM; EUROPEAN COMMUNITY; WESTERN EUROPE

Accession no.405626

EASTERN EUROPE; USSR

Accession no.407918 Item 318 SATRA Bulletin July/Aug.1990, p.77-80 GUIDELINES FOR BETTER SPORTS FOOTWEAR Worswick B;Cross S SHOE & ALLIED TRADES RESEARCH ASSN. The performance levels to be expected from a variety of different sports shoe materials and constructions are reviewed. Recommendations for upper materials for use in sports footwear and constructional guidelines are presented. The suitability and minimum thicknesses of soles for sports shoes are indicated and methods of avoiding discolouration problems and adhesion problems are highlighted. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.407205 Item 319 Adhasion 34, No.3, March 1990, p.21-3 German DEFECTS IN WINDOW SEALING Froelich H INSTITUT FUER FENSTERTECHNIK EV The paper explains how moisture can gain access to the sealant and suggests remedies. Sometimes redesign of the sealant elements is the only solution to the problem. INSTITUT DES GLASERHANDWERKS EUROPEAN COMMUNITY; WEST GERMANY; WESTERN EUROPE

Accession no.406897

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Item 321 Contraception 41, No.6, June 1990, p.591-603 HIGH SPEED CINEMATOGRAPHY OF THE INITIAL BREAK POINT OF LATEX CONDOMS DURING THE AIR BURST TEST Stube R;Voeller B;Davidhazy A CONSUMERS UNION; MARIPOSA FOUNDATION; ROCHESTER, INSTITUTE OF TECHNOLOGY The location of break initiation and the direction of break propation in latex condoms inflated to burst under standard (ISO) conditions were investigated using highspeed cinematography. It was found that rupture of the condom was initiated at a small focal point on the shank of the condom and rapidly propagated throughout the condom’s surface, often ending with partial or full severance of the condom at its point of attachment to the air burst instrument. 10 refs. USA

Accession no.403447 Item 322 Revue Generale des Caoutchoucs et Plastiques No.692, Dec.1989, p.114-25 French HIGH PERFORMANCE EVALUATION TECHNIQUE FOR RUBBERS Cardinet C;Verschave A HUTCHINSON SA A detailed account is presented of the use of scanning electron microscopy in conjunction with energy selection X-ray spectrometry to investigate features of rubbers such as heterogeneity of composition, visual defects, blooming, surface coatings, interfacial characteristics and surfaces of substrates. Diagrammatic representations of equipment,

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References and Abstracts

electron micrographs, and X-ray spectrogrammes are included. 3 refs. EUROPEAN COMMUNITY; FRANCE; WESTERN EUROPE

Accession no.401936 Item 323 Washington, DC, 1990, pp.v, 55. 11ins. 20/8/90. 42C11C12D1-6R43-9(12)4 STRENGTH AND CREEP-RUPTURE PROPERTIES OF ADHESIVE-BONDED EPDM JOINTS STRESSED IN PEEL Martin J W;Embree E;Stutzman P E;Lechner J A US, NATIONAL INST.OF STANDARDS & TECHNOLOGY NIST Building Science Series 169 The most frequently reported fault in EPDM single ply roofing systems is in field formed joints. This technical report finds the cure time and level of cleanness of the EPDM membrane have the greatest effect on joint strength, while the thickness of the adhesive and the magnitude of the mechanical load have the greatest effect on a joints creep rupture time to failure. The rankings of variables in creep rupture and short time strength experiments were different, and this difference should have important implications in standards writing and in establishing performace requirements for EPDM roofing joints. 42 refs.

polydienes are considered and details are given on suitable antiozonants. Particular attention is paid to developments in the field of non-staining antiozonants. 124 refs. EUROPEAN COMMUNITY; WEST GERMANY; WESTERN EUROPE

Accession no.399717 Item 326 NR Technology 20, No.4, 1989, p.65-71 EFFECTS OF ANTIOXIDANTS ON THE AGEING OF NATURAL RUBBER LATEX THREAD Gorton A D T;Knobloch G;Bauer R;Raue D P;Chen Ying CIBA-GEIGY AG; MALAYSIAN RUBBER PRODUCERS’ RESEARCH ASSN.; SOUTH CHINA, ACADEMY OF TROPICAL CROPS Ten antioxidants were studied under conditions of dry heat ageing, a washing treatment followed by hot air ageing, outdoor exposure, and weatherometer tests. It was found that the efficiency of the antioxidant depended on the ageing conditions, although some were used at a lower concentration than others. It is suggested that combinations of selected antioxidants might give improved results. 7 refs. UK; WESTERN EUROPE

Accession no.397356

USA

Accession no.401308 Item 324 SATRA Bulletin June 1990, p.70-1 POLYURETHANE COATED FABRICS: REIVEW OF GUIDELINES Rose S SATRA FOOTWEAR TECHNOLOGY CENTRE A comprehensive review is given of SATRA’s current performance recommendations for PU coated fabrics. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.400398 Item 325 Kautchuk und Gummi Kunststoffe 42, No.9, Sept.1989, p.760-70 German OZONOLYSIS OF UNSATURATED RUBBER AND THEIR VULCANISATES. SURVEY Brueck D BAYER AG This article reviews literature on ozone reaction with diene rubbers. Physical and chemical phenomena of rubber ageing by ozone and mechanisms of ozone reaction with rubbers are described. Possibilities of improving ozone resistance of rubbers and vulcanisates made from

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Item 327 Adhesion 14. Barking, Elsevier Applied Science, 1990, p.126-60. 9(12)4 ADHESIVE COMPOSITION SYSTEMS IN DEGRADATIVE CONDITIONS Kovacevic V;Kliajie-Malinovic L J;Smit I;Bravar M;Agic A;Cerovecki Z ZAGREB, UNIVERSITY Edited by: Allen K W (London, City University) Results are presented of a studies of the ageing of PU adhesives for leather, the adhesives used being based on hydroxyl-terminated PU prepolymers prepared from suitable adipate polyesters and aromatic isocyanates. Particular attention is paid to the yellowing of white leather in contact with the adhesive. 35 refs. YUGOSLAVIA; EASTERN EUROPE

Accession no.396761 Item 328 Rubber and Plastics News 18th Oct.1989, p.Special Issue, p.10 OEMS EXPECT REFINEMENT IN TYRE TECHNOLOGY Rowand R According to executives at the top three US automotive companies - General Motors, Ford Motor and Chrysler -

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References and Abstracts

tyre makers have done a good job in overcoming tyre vibration, harshness of ride, noise, leaks, flat spots, lack of durability and other technical problems; in the future, they will have to do more. Details are given. CHRYSLER CORP.; FORD MOTOR CO.; GENERAL MOTORS CORP. USA

Accession no.394973 Item 329 China Rubber Industry 36, No.10, Oct.1989, p.613-6 Chinese ABRASION FAILURE OF VULCANISATES CONTAINING SHORT FIBRES Wang Weidong;Wang Mengjiao;Zhang Tao BEIJING, RESEARCH & DESIGN INST.OF RUBBER IND. The relationship between abrasion resistance and fibre orientation was investigated along with the influence of adhesive on abrasion using SEM. It was found that the presence of short fibres in the composite gave rise to changes in the failure mechanism and that fibre orientation had varying effects on the abrasion resistance of the composite. 9 refs. CHINA

Accession no.393327 Item 330 Modern Tire Dealer 70, No.7, June 1989, p.28/35 UNDERSTANDING AND CORRECTING IRREGULAR WEAR ON RADIAL TYRES Jones A Irregular wear is said to be initially attributable to tyre design, service use, maintenance and the state of the vehicle on which they are used. Rapid irregular shoulder wear is caused primarily by excessive low contact pressure in the shoulder area. River wear or tramlining is caused by high compression which forces the rib edges to spread and abrade on the road. These defects are examined along with the effects of poor tyre and vehicle maintenance. USA

Accession no.390812 Item 331 Biomaterials 10, No.9, Nov.1989, p.625-9 APPLICATION OF AN EMPIRICALLY DERIVED GROWTH CURVE MODEL TO CHARACTERISE STAPHYLOCOCCUS EPIDERMIDIS BIOFILM DEVELOPMENT ON SILICONE ELASTOMER Holmes C J;Evans R C;Vonesh E BAXTER HEALTHCARE CORP. 24 refs USA

Accession no.390797

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Item 332 Rubbercon ’88.Developed from an international conference. Sydney, 10-14th Oct.1988, Vol.2, Paper 16, pp.30. 012 FRACTURE PROCESSES IN ELASTOMERS IN SEVERE SERVICE CONDITIONS Stevenson A MATERIALS ENGINEERING RESEARCH LABORATORY LTD. (PRI;Pacific Dunlop Ltd.; XPO Exhibitions) Some recent developments in understanding the physics of failure mechanisms in elastomers, with particular reference to severe mechanical and environmental conditions relevant to offshore engineering applications, are presented. NBR, chlorinated PE, polychloroprene and NR are subjected to high mechanical stresses and severe hydrocarbon fluid environments at elevated temperatures in an attempt to determine component service life. 14 refs. UK; EUROPEAN COMMUNITY

Accession no.390328 Item 333 Rubbercon ’88.Developed from an international conference. Sydney, 10-14th Oct.1988, Vol.2, Paper 3, pp.13. 012 LASER HOLOGRAPHY FOR INSPECTION OF TYRE Shaoying Z;Yufang S;Bingyu L;Zhi Z BEIJING, RESEARCH & DESIGN INST.OF RUBBER IND. (PRI;Pacific Dunlop Ltd.; XPO Exhibitions) The utilisation of laser holographic interferometry, vacuum stressing and the analysing of the interference fringes of double-exposure of tyres to evaluate tyre structural uniformity, define the type of the defects and to estimate their size is described. Photographs of reconstructed holographic interference patterns of tested tyres are given. 8 refs. CHINA

Accession no.390322 Item 334 Rubbercon ’88.Developed from an international conference. Sydney, 10-14th Oct.1988, Vol.1, Paper 20, pp.12. 012 PROCESSING OPTIONS OF FLUOROCARBON ELASTOMERS Kosmala J L;Micallef J 3M CO. (PRI;Pacific Dunlop Ltd.;XPO Exhibitions) A general guide is presented aimed at providing fabricators with a basic understanding of the effects of polymer type, cure systems, compounding ingredients, processing conditions and part/mould design to efficiently process FKM fluoroelastomers. A trouble-shooting guideline for fluoroelastomers is also given.

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References and Abstracts

USA

Accession no.389330 Item 335 Fall Meeting(134th), 1988. Cincinnati, Oh., 18-21st Oct.1988, Paper 43, pp.30. 012 INFRARED SPECTROSCOPIC STUDY OF PETP DEGRADATION IN POLYESTER FIBRE/ NITRILE RUBBER COMPOSITES Carduner K R;Carter R O;Peck M C P;Killgoar P C FORD MOTOR CO. (ACS, Rubber Div.) The results are reported of the application of Fourier transform IR spectroscopy to the study of the chemical degradation of a PETP fibre/nitrile rubber composite under consideration for use in an experimental automotive subsystem. It is shown that the mechanism of polyester decomposition responsible for failure is aminolysis. 9 refs. An appendix is included, which presents data for unadulterated and modified PETP samples and describes a successful attempt to identify anomalous broadening of intense bands observed in the spectrum of fibres, where strength is preserved. 21 refs.

temps. of sufficient quantities of a volatile decomposition product. The reaction was, however, specific to the particular elastomer and crosslinking system employed. 10 refs. USA

Accession no.386943 Item 338 Spring Meeting (133rd), 1988. Dallas, Tx., 19-22nd April 1988, Paper 1, pp.36. 012 FRACTURE MECHANISMS AND LIFE PREDICTIONS FOR ELASTOMERS IN HIGH PRESSURE OIL AND GAS ENVIRONMENTS Stevenson A;Campion R P MATERIALS ENGINEERING RESEARCH LABORATORY LTD. (ACS, Rubber Div.)

USA

Failure mechanisms in elastomers subjected to high pressures are discussed, initially from a purely mechanical viewpoint and subsequently in relation to the effects of hydrocarbon liquids and gases at elevated temps. Some preliminary experimental results for nitrile rubber, chlorinated PE, polychloroprene and NR are presented. 13 refs.

Accession no.389096

UK

Accession no.386925 Item 336 Fall Meeting(134th), 1988. Cincinnati, Oh., 18-21st Oct.1988, Paper 16, pp.15. 012 QUALITY IMPROVEMENT THROUGH ROOT CAUSE ANALYSIS Floyd R C EXXON CHEMICAL CO. (ACS, Rubber Div.) The concept of root cause analysis, which is fundamentally concerned with the cause-and-effect chain of an operation, is described. Some examples of root cause analysis are presented, which demonstrate how it works, and a few simple rules, which must be followed to achieve the desired end-result, are outlined. USA

Accession no.388771 Item 337 Spring Meeting(133rd), 1988. Dallas, Tx., 19-22nd April 1988, Paper 41, pp.31. 012 HEAT BUILD-UP AND BLOW-OUT OF RUBBER BLOCKS Hindi M;Gent A N AKRON, UNIVERSITY (ACS, Rubber Div.) Studies with thick rubber blocks of SBR, NR, polybutadiene and butyl rubber (as used in articles such as tyre treads and tank track pads) showed that the principal cause of blow-out was the generation at high

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Item 339 Spring Meeting(133rd), 1988. Dallas, Tx., 19-22nd April 1988, Paper 18, pp.35. 012 FIELD OBSERVATIONS ON RUBBER TANK TRACKS Pergantis C G;Murray T J;Mead J L;Shuford R J;Alesi A L US, ARMY MATERIALS TECHNOLOGY LAB. (ACS, Rubber Div.) IR thermography was used to observe elastomer surface temps. of the ground pad side of US Army track shoes operating on an M-1 tank. The observations were made to define the temps. generated by tank track pads under field test conditions (on paved road) in order to relate them to wear and failure modes of abrasion, cutting and chunking, and blow-out. Elastomers investigated and compared included SBR, NR and highly-saturated NBR. Local surface temps. were affected by ground pad design, pad location, the roadwheel path and the type of material. The thermal behaviour of the rubber bushings was also analysed. 8 refs. USA

Accession no.386647 Item 340 Journal of Natural Rubber Research 4, No.2, June 1989, p.93-106 CREEP BEHAVIOUR OF RUBBERS SUBJECTED TO REPEATED LOADINGS

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References and Abstracts

Pond T J MALAYSIAN RUBBER PRODUCERS’ RESEARCH ASSN. The creep behaviour of various vulcanised rubbers under cyclic conditions has been compared with that under constant loading. Cyclic loading is found to produce an enhancement of creep rates thought to be due to crosslinks breaking under stress concentrations caused by crystallisation. Half of the cyclic creep can be accounted for in this way; visco-elasticity accounts for the remainder. 6 refs. MALAYSIA; UK

Accession no.386035 Item 341 International Polymer Processing 4, No.1, March 1989, p.3-8 ANALYSIS OF AGGLOMERATE RUPTURE IN LINEAR FLOW FIELDS Manas-Zloczower I;Feke D L CASE WESTERN RESERVE UNIVERSITY A dispersive mixing model focussing on the rupture of agglomerates as the step that primarily determines the dynamics of the mixing process has been derived and analysed. Rupture is predicted to occur when hydrodynamic forces exerted on the outer surface of the agglomerate exceed cohesive forces binding the agglomerate together. Agglomerates are modelled as clusters of aggregates bound by van der Waals forces. An analysis is made of agglomerate rupture in four flow geometries: simple shear, pure elongation, uniaxial extension and biaxial extension. 13 refs. USA

Accession no.382415 Item 342 Journal of Polymer Science : Polymer Chemistry Edition 27, No.7, June 1989, p.2313-24 POLYMER DEGRADATION UNDER IONISING RADIATION: ROLE OF OZONE Clough R L;Gillen K T SANDIA NATIONAL LABORATORIES A study was made of the gamma-radiation degradation of SBR and Buna-n rubber in the presence of air. Using a recently developed modulus profiling technique, it is shown that degradation is very heterogeneous through the sample thickness. Degradation is considered to result from two different processes, namely free radical-mediated radiation chemistry and ozone chemistry in the surface regions of the samples. The synergistic action of ozone and ionising radiation is discussed. 29 refs. USA

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Item 343 Journal of Polymer Science : Polymer Chemistry Edition 27, No.7, June 1989, p.2435-55 OZONOLYSIS OF BUTYL AND HALOBUTYL ELASTOMERS Ho K W;Guthmann J E POLYSAR LTD. A study was made of the ozonolysis of butyl rubber and its halogenated derivatives, as well as their model compounds in hexane. The effect of various additives, such as diphenylamine, triisopropyl phosphite, hexylamine and 2, 6-di-tert-butyl cresol, on chain scission and rearrangement of bromobutyl rubber, was also evaluated. It was found while the ozonolysis of butyl and chlorobutyl rubbers involved normal cleavage of olefinic double bonds, the mechanism of ozonolysis of bromobutyl rubber was more complicated. 8 refs. CANADA

Accession no.381828 Item 344 Tire Science and Technology 17, No.2, April-June 1989, p.100-8 TYRE DESIGN THEORY BASED ON OPTIMISATION OF STRESS-STRAIN CYCLES OF ITS ELEMENTS Tretyakov O B;Sokolov S L MOSCOW, TYRE RESEARCH INSTITUTE Some criteria are presented for evaluating the various tyre design theories that are based on the equilibrium shape of the sidewall and on the rolling contour of a tyre. Tyre failure types and the mathematical models by which they can be predicted by modern theories of rubber/cord fatigue are also described. A tyre design theory based on stressstrain optimisation of its elements is proposed as is a hierarchic system of complicated tyre models for calculation of stress-strain cycles. Influence of the crosssection geometry and of the inner structure of the tyre on stress-strain cycles in the belt and bead of radial tyres is investigated. 21 refs. USSR; EASTERN EUROPE

Accession no.380697 Item 345 Rubber World 200, No.1, April 1989, p.31-8 FIELD OBSERVATIONS ON RUBBER TANK TRACKS Pergantis C G;Murray T;Mead J L;Shuford R J;Alesi A L US, ARMY MATERIALS TECHNOLOGY LABORATORY Information is presented in detail on data obtained from testing of rubber tank tracks for Army tracked vehicles such as the M-1 Abrams tank. Main areas of failure of rubber track pads are identified and results of field tests are

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References and Abstracts

presented. Methods of testing included the use of infrared thermography for monitoring thermal behaviour of the track pads. Materials studied included nitrile rubber, triblends, natural rubber and fibre-filled rubber pads. 8 refs. USA

Accession no.379956 Item 346 Kautchuk und Gummi Kunststoffe 41, No.10, Oct.1988, p.992-6 German PRODUCTION FACTORS INFLUENCING THE QUALITY OF ELASTOMERIC INJECTION MOULDINGS - REQUIREMENTS OF AN AUTOMOTIVE USER Walter G DAIMLER-BENZ AG An inspection by Daimler-Benz of elastomer components for use in car construction showed that the percentage of defective components was much higher than that for plastics or metal parts. Reasons for this situation are discussed and ways and methods (failure mode effects analysis and statistical process control) of improving the quality of rubber injection mouldings outlined. It is concluded that quality should be achieved by quality planning and development rather than by quality control. 13 refs. WEST GERMANY

Accession no.379264 Item 347 International Polymer Science and Technology 15, No.9, 1988, p.T/83-6 STUDY OF THE BREAKDOWN OF SEALS WITH CYCLIC TEMPERATURES Shpindler V M;Zuev Yu S;Bondareva V S;Sveshnikova N V;Chulyukina A V;Yudina G I USSR, RUBBER RESEARCH INSTITUTE 3 refs. (Full translation of Prom.Sint.Kauch.Shin i Rez.tekhn.Iz., No.6, 1988, p.23) USSR

Accession no.379092 Item 348 International Polymer Science and Technology 15, No.9, 1988, p.T/30-1 EFFECT OF VIBRATION ON THE SEALING POWER OF RUBBER GASKETS IN FIXED JOINTS Shtitel’man M I;Sedov V V;Yurtsev N N 9 refs. (Full translation of Kauch.i Rezina, No.6, 1988, p.23B) USSR

Accession no.379082

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Item 349 CETIM Informations No.105, April 1988, p.53-7 French SEALS FOR ROTATING SHAFTS: STUDY OF LEAKAGES Faure L CENTRE TECHNIQUE DES INDUSTRIES MECANIQUES Results are presented of a study of oil leakages from nitrile rubber rotary shaft seals. 1 ref. FRANCE

Accession no.377540 Item 350 International Polymer Science and Technology 15, No.8, 1988, p.T/19-22 CALCULATION OF THE BURSTING ENERGY OF HOSES Huszka J Full translation of Muanyag es Gumi, No.12, 1987, p.381) HUNGARY

Accession no.375889 Item 351 NR Technology 19, No.3, 1988, p.50-8 STUDY OF THE BIODETERIORATION OF VULCANISED RUBBER PIPE SEALS EXPOSED TO INOCULATED TAP WATER Hanstveit A P;Gerritse G A;Scheffers W A DELFT, UNIVERSITY; TNO; TNO PLASTICS & RUBBER RESEARCH INSTITUTE A novel NR vulcanisate containing a fungicidal plasticiser (chlorinated paraffin) was tested for its resistance to attack by the rubber-degrading bacterium, Nocardia asteroides, under conditions which simulated those of pipe seals in water supply pipes. The vulcanisate was exposed to tap water inoculated with the bacteria and the growth of bacteria on the surface of the material and any resultant deterioration were monitored by SEM, fluorescence microscopy, TEM, viable counts in selective media and tensile strength determination. After an exposure of nearly two years, the samples were found to have undergone no significant deterioration. 23 refs. NETHERLANDS

Accession no.373613 Item 352 Journal of Biomaterials Applications 3, No.2, Oct.1988, p.207-27 BIOMEDICAL APPLICATIONS OF POLYURETHANES: IMPLICATIONS OF FAILURE MECHANISMS Phillips R E;Smith M C;Thoma R J

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References and Abstracts

CARBOMEDICS INC.; INTERMEDICS INC.

Item 355 Rubber World 199, No.1, Oct.1988, p.12/51 MAKING IT LAST Menough J

Three mechanisms are described which explain various observed interactions between PU chemistry and body chemistry. These include calcification, environmental stress cracking and chain scission. Each may result in implant device failure and each appears to involve metal ion complexation as a key parameter. Continued expansion of PU into implantable product applications will require further clarification of the effect of each of these interactions on long-term product performance. 25 refs.

USA

USA

Accession no.369899

Some of the typical causes of rubber product failure are reviewed, and some of the potential methods of overcoming these problems are described. Aspects covered include abrasion, oxidation, chemical attack, permanent set and heat/cold.

Accession no.373588 Item 353 International Polymer Science and Technology 13, No.7, 1986, p.T/31-40 BLISTERING OF SEAL RINGS IN STERN TUBE SEALS Yamajo S;Yokoyama T;Ishikawa H The relationship between the nature of the sealing ring material (fluoroelastomer) and the ocurrence of blistering was investigated. The results indicated that blistering occurred more readily when the crosslink density was high as a result of over-vulcanisation. The filler was found to dissolve out into water more easily in parts which were subjected to a large stress due to deformation of the rubber. It was possible that traces left behind after dissolution of the filler provided nuclei for crack formation which led to the occurrence of blistering. 4 refs. (Full translation of Nippon Gomu Kyokaishi, 58, No.4, 1985, p.266) JAPAN

Accession no.371989 Item 354 Rubber World 199, No.1, Oct.1988, p.16/24 EFFECT OF THE ADDITIVES IN DOMESTIC WATER SYSTEMS ON RUBBER VULCANISATES Simmons C L;Evanson P P MINNESOTA RUBBER; POLYSAR LTD. Failure of rubber parts used in domestic water applications has been frequently reported, and complaints include swelling and cracking and are related to nitrile and ethylene-propylene copolymer-type compounds. An ageing test method is developed, and effects of the different chemicals used in the purification processes on nitrile and EPDM vulcanisates compared. Butyl, halobutyls, ethylene-propylene copolymers and nitrile vulcanisates are evaluated; two failure mechanisms are proposed and investigated. 7 refs. USA

Accession no.369900

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Item 356 Adhesion International 1987, Proceedings of the 10th Annual Meeting held Williamsburg, Va., 23-27 Feb.1987. Montreux, Gordon & Breach Science Publishers, 1988, p.153-66. 9(12)4 EFFECT OF WATER ON MATRIX/FILLER ADHESION IN A POLYURETHANE ELASTOMER Bowditch M R;Stannard K J UK, ADMIRALTY RESEARCH ESTABLISHMENT Edited by: Sharpe L H (Adhesion Society Inc.) The static moduli failure stresses and dynamic moduli of both filled and unfilled polyurethanes are measured over a range of equilibrium water contents and these results are compared with those obtained from dry controls. The degradation of mechanical properties in the presence of water, and the hydrolytic disruption of filler/matrix adhesion is assessed. A quantitative relationship between the water content and mechanical properties is established and the mechanics of the water/polymer/filler interaction are considered. 4 refs. UK

Accession no.368269 Item 357 Adhesion International 1987, Proceedings of the 10th Annual Meeting held Williamsburg, Va., 23-27 Feb.1987. Montreux, Gordon & Breach Science Publishers, 1988, p.137-52. 9(12)4 EFFECT OF ELECTROCHEMICAL POTENTIALS ON THE DURABILITY OF RUBBER/METAL BONDS IN SEA WATER Stevenson A MATERIALS ENGINEERING RESEARCH LABORATORY LTD. Edited by: Sharpe L H (Adhesion Society Inc.) A study of the role of electrochemical potentials on the durability of rubber/metal bonds in sea water is described. The effect of electrochemically inert conditions is shown

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References and Abstracts

to be measured in stable bond strength after years. The effect of bonding of the rubber to the more noble of a pair of metals in electrical and electrolytic contact, however, is shown to cause bond failure much faster. 4 refs. UK

Accession no.368118 Item 358 Polymers in Offshore Engineering.Proceedings of the 4th International Conference. Scotland, 14-16 June 1988, p.5/1-5/14. 63Pet FAILURE MECHANISMS IN ELASTOMERS IN HIGH PRESSURE OIL AND GAS CONDITIONS Campion R P MATERIALS ENGINEERING RESEARCH LABORATORY LTD. (PRI) Experimentation at temps. up to 130C and pressures up to 700 atmospheres was carried out to assess the explosive decompression performance of a number of elastomeric compounds. Permeation measurements showed that permeation rate decreased from proportionality against pressure at high pressures, and at 700 atm. and 27C for carbon dioxide (now a liquid) permeation apparently was effectively halted; reasons suggested include the forced close packing of molecular chains and the dependency of D on concentration. These observations are discussed together with aspects of nucleation, bubble growth and elastomer fracture: an optimised balance of properties related to these factors is presumably necessary for an elastomer to withstand explosive decompression. 10 refs. UK

Accession no.367343 Item 359 Expanding Technology and Markets for Adhesives and Sealants; Conference Proceedings. Philadelphia, Pa., 18-21 Oct.1981, p.244-50. 6A1 SEALANTS - ARE THEY TRULY THE MIRACLE COMPOUND - ALL THAT WE HAVE BEEN LED TO BELIEVE? Grenadier G GRENADIER CORP. (US, Adhesives & Sealants Council) A contractor’s view that sealants are not what they are supposed to be and certainly are not what they used to be is discussed. Factors contributing to the denigration of sealants in recent years are briefly considered and ways of improving the quality of sealants are suggested. USA

Accession no.367165 Item 360 Polymers in Offshore Engineering.Proceedings of the 4th International Conference.

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Scotland, 14-16 June 1988, p.9/1-9/10. 63Pet INTRODUCTION OF AN IMPROVED ELASTOMER FOR HIGH PRESSURE PIPEWORK FITTINGS Rispin A;Phelan P ANSON LTD.; WALKER J., & CO.LTD. (PRI) The problem of explosive decompression damage to oilfield flowline equipment prompted the development of James Walker’s FR58/90 fluoroelastomer. The research, development and field testing of Union seals made of this material is described. The Anson Superseal has now been approved and accepted by major operators for sour gas explosive decompression service. 2 refs. UK

Accession no.367095 Item 361 PMA’s Reference Guide to Polyurethane Processing. Glen Ellyn, Il., c.1986, p.IV 104-10. 43C6 PROBLEM SOLVING IN POLYURETHANE BONDING Stahr B WHITTAKER CORP. (Polyurethane Manufacturers Assn.) A detailed description is given of the problems encountered in the bonding of PU, and logical methods of analysing and solving bonding problems are presented. USA

Accession no.366056 Item 362 Elastomerics 120, no.7, July 1988, p.50 SPACE SHUTTLE REDESIGN POSES CRITICAL CHALLENGE TO THE RUBBER INDUSTRY Hertz D L The tendency of fluoroelastomers to lose resilience at lower temperatures is said clearly to be a major cause of the failure of the Challenger space shuttle. Redesign engineers have concluded that fluoroelastomers are still the best material available for the construction of the Orings; details are given. NATIONAL RESEARCH COUNCIL USA

Accession no.365816 Item 363 Plastics Southern Africa 18, No.2, Aug.1988, p.78/82 QUALITY ASSURANCE. PART I Ford R H SOUTH AFRICA, BUREAU OF STANDARDS The terms ‘quality management’, ‘quality assurance’ and ‘quality control’ are explained and examples of the need

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for quality assurance given. The implementation of quality assurance on the factory floor is emphasised. (Pt.II is to appear in the Sept.1988 issue). SASOC; SASOL SOUTH AFRICA

Accession no.365468 Item 364 Journal of Adhesion 21, Nos.3/4, 1987, p.329-41 EFFECT OF WATER ON MATRIX/FILLER ADHESION IN A PU ELASTOMER Bowditch M R;Stannard K J UK, ADMIRALTY RESEARCH ESTABLISHMENT The static moduli, failure stresses and dynamic moduli of an unfilled and filled polyether-urethane were measured over a range of equilibrium water contents and the results obtained compared with those for dry controls. Fillers employed were barytes (and small amounts of fumed silica and carbon black) or iron oxide. A quantitative relationship between water content and mechanical properties was established and the mechanics of the water/ polymer/filler interaction assessed. (Tenth Annual Meeting of the Adhesion Society Inc., Williamsburg, Virginia, USA, 22-27 Feb.1987). 4 refs. UK

Accession no.365347 Item 365 Adhasion 32, Sept.1988, p.32-4 German QUALITY ASSURANCE IN THE ADHESIVES INDUSTRY Bucken H J;Van Halteren A FACHVERBAND KLEBSTOFFINDUSTRIE EV; HENKEL KG A description is given of a system of quality assurance, developed by the West German Association of the Adhesives Industry, which takes into account the requirements of its various customers. Based on DIN/ISO 9004, it analyses the possible defects and their results and derives statistical process control data and quality cards based on this analysis. 12 members of the quality assurance association are listed. BAYER AG; VOLVO AB WEST GERMANY

Accession no.364963 Item 366 Journal of Adhesion 21, Nos.3/4, 1987, p.313-27 EFFECT OF ELECTROCHEMICAL POTENTIALS ON THE DURABILITY OF RUBBER/METAL BONDS IN SEA WATER

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Stevenson A MATERIALS ENGINEERING RESEARCH LABORATORY LTD. A study was made of the effect of electrochemical potentials on the durability of double shear type samples consisting of 2 black filled NR and 3 metal discs alternately bonded together. Metals employed were carbon steel, Inconel, stainless steel, titanium and titanium alloy. The influence of dissimilar metals in contact, high cathodic potentials and elastomer strain was evaluated and the results discussed in terms of failure penetration depth. (Tenth Annual Meeting of the Adhesion Society Inc., Williamsburg, Virginia, USA, 22-27 Feb.1987). 4 refs. UK

Accession no.364839 Item 367 Adhesives, Sealants, and Coatings for Space and Harsh Environments.Conference Proceedings. Denver, Colorado, 7-9 April 1987, p.371-80. 63Tr.Sp. INFLUENCE OF COMPOSITION AND FILM THICKNESS ON BIOACTIVITY OF ANTIFOULING PAINTS CONTAINING CASTOR OIL AS THE THIXOTROPIC AGENT Giudice C A;del Amo B;Rascio V J D CIDEPINT (ACS, Div.of Polymeric Materials Science & Engng.) The results are reported of a study of the influence of chemical composition and film thickness on the biological activity of high-build anti-fouling paints containing gum rosin and chlorinated rubber as binders. Variables investigated were rosin/chlorinated rubber ratio, binder percentage, cuprous oxide content, amount of castor oil incorporated as gel, dispersion time of toxicant and dry film thickness. Raft tests were carried out on steel plates coated with the paint and immersed for 25 months in sea water at Puerto Belgrano. 14 refs. ARGENTINA

Accession no.364050 Item 368 Developments in Rubber Technology-4. Barking, Elsevier Applied Science Publishers Ltd., 1987, p.159-91. 012 REVIEW OF ELASTOMERS USED FOR OILFIELD SEALING ENVIRONMENTS Revolta W N K;Sweet G C DU PONT (UK) LTD. Edited by: Whelan A;Lee K S A general overview is given of elastomers used for sealing applications during the exploration and production of oil and gas. An attempt is made to define the main problem areas and to give broad distinctions between different elastomers to highlight their strengths and weaknesses. 19 refs. UK

Accession no.361195

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References and Abstracts

Item 369 International Rubber Conference IRC 86;Proceedings. Goteborg, 1986, Vol.2, p.459-63. 012 SERVICE LIFE OF HYDRAULIC HOSE COMPONENTS USED IN OFFSHORE OIL APPLICATIONS Hampson F W;Manley T R NEI CLARKE CHAPMAN LTD.; NEWCASTLEUPON-TYNE, POLYTECHNIC (Swedish Institution of Rubber Technology) The results are reported of a study of the service life of heavily worked hydraulic hose components subject to impulse conditions over long periods using DSC. Tests were carried out on a PU modified umbilical hose component transmitting fluid power from an offshore structure to a submersible or submerged structure and a high pressure, flexible hose with an inner lining of oilresistant rubber, steel wire reinforcement and rubber cover. The relationship between oxidative thermal degradation changes and mechanically induced fatigue of the polymers is demonstrated. 2 refs. UK

Accession no.359815 Item 370 International Rubber Conference IRC 86;Proceedings. Goteborg, 1986, Vol.2, p.347-52. 012 IMPROVEMENT OF RUBBER JOINTS FOR LOCOMOTIVE TRANSMISSION GEAR Schenk H (Swedish Institution of Rubber Technology) Tests were carried out on rubber joints for locomotive transmission gears, which had unexpectedly failed prematurely, to determine the cause of damage and provide the basis for corrective measures. The fatigue life of the specimens at 60 Shore hardness was investigated as a function of alternating radial loads and the influence of rubber hardness on fatigue life at a force level of + or - 30KN evaluated. The effect of tangential stressing at higher rubber hardness levels was also examined and the consequences of using a rubber layer of thinner thickness in the joints assessed. 1 ref. (German translation appears in Kaut.u.Gummi Kunst., 40, No.4, 1987, p.343-5.) WEST GERMANY

Accession no.359812 Item 371 International Rubber Conference IRC 86;Proceedings. Goteborg, 1986, Supplementary Volume, p.175-85. 012 THE SPECIFICATION - ITS ROLE IN QUALITY ASSURANCE Clowes F BRITISH RAILWAYS BOARD (Swedish Institution of Rubber Technology) The usefulness of standards and quality control in everyday life is emphasised and definitions of

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‘specification’ are set out. The pitfalls inherent in overspecifying and under-specifying are described and the basic requirements outlined. The terms ‘quality’, ‘quality control’ and ‘quality assurance’ are defined and the requirements as far as management organisation, manufacturing control and training are detailed. BRITISH STANDARDS INST.; EUROPEAN ORGANISATION FOR QUALITY CONTROL; INTERNATIONAL STANDARDS ORGANISATION SWEDEN; UK

Accession no.359356 Item 372 Rubber and Plastics News 17, No.22, 16th May 1988, p.28 ARMY RESEARCHERS CREATE TANK PADS BASED ON SATURATED NBR It is claimed that the development of a nitrile rubber-based compound for battle tank track pads could save the US Army million of dollars in maintenance costs. Researchers at the Army Materials Research Laboratory and Belvoir Research Development & Engineering Centre developed a highly saturated nitrile rubber compound in 1987 in an attempt to make the pads, currently moulded in SBR, wear longer. Details are given. BELVOIR RESEARCH DEVELOPMENT & ENGNG.CENTER; FMC CORP.; US, ARMY MATERIALS TECHNOLOGY LABORATORY USA

Accession no.358151 Item 373 Adhesives Age 31, No.5, May 1988, p.28-9 ANAEROBIC ADHESIVE IMPROVES ROLLER ASSEMBLY RELIABILITY Loven W E HENKEL ADHESIVES CO. The change by a manufacturer of automated teller machine rollers from one anaerobic adhesive to another to meet performance requirements is examined. Topics covered include assembly procedures, testing and cost savings; in the two years that Hiawatha Rubber has been using the anaerobic adhesive, only two bonded rollers out of about 16, 000 units have failed - each time attributed to improper application of the adhesive. Details are given. HIAWATHA RUBBER CO. USA

Accession no.355963 Item 374 Adhesives & Sealants in Building & Construction. London, Feb.22, 1988, Paper 1. 62Bu-6A SERVICE EXPERIENCE OF ADHESIVES AND SEALANTS IN BUILDING

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Berman A M AMBER SCIENTIFIC LTD. (PRI) An attempt is made to justify the ‘belt and braces’ approach as a logical outcome of experience of practical applications of sealants and adhesives in construction work. Consideration is given to the probability of failure/ success, adhesive/substrate compatibility, workmanship/ quality control, problem prevention and where not to use adhesives.

REVIEW OF QUALITY IN THE BRITISH RUBBER INDUSTRY. PAST, PRESENT AND FUTURE Coulson S H;Cousans J A EXXON CHEMICAL INTERNATIONAL INC. The development of quality control systems in the British rubber industry from 1918 to date has been reviewed. The barriers to complete acceptance of modern quality systems in the British rubber industry are identified and analysed. 221 refs.

UK

BELGIUM; UK

Accession no.354170

Accession no.351308

Item 375 Tire Business 5, No.22, 29th Feb.1988, p.13 PROPER TYRE MAINTENANCE KEY TO CASING LIFE Ball C A

Item 378 Kautchuk und Gummi Kunststoffe 40, No.7, July 1987, p.642-50 German PRECISION OF ANALYTICAL METHODS FROM QUALITY ASSURANCE POINT OF VIEW Schuster R H

The causes of tyre damage and wear, such as underinflation, overloading, high speeds, driver behaviour, road conditions, climate and mechanical conditions are examined. The necessity for a tyre to be properly fitted, balanced and serviced throughout its original life if it is to provide a sound foundation for retreading is emphasised. USA

Accession no.353435 Item 376 Revue Generale des Caoutchoucs et Plastiques 64, No.672, Oct.1987, p.125-31 French EFFECTS OF ENGINE LUBRICANT ADDITIVES ON FLUOROELASTOMERS Frapin B PROCAL SA A study was made of the effects of engine lubricant additives, including dispersing agents, detergents, antioxidants and viscosity modifiers, on the mechanical properties of automotive seals made of vinylidene fluoride-hexafluoropropylene copolymer and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer fluoroelastomers. Two groups of additives, dispersing agents and viscosity modifiers, showed the most distinct effects due to their dispersing properties, but interactions between different groups of additives were also significant. The tests also established a correlation between static and dynamic tests. 10 refs.

Analytical methods employed in the rubber industry are reviewed. Their accuracy is discussed, together with factors influencing accuracy, e.g. instrument errors. Methods considered are: IR spectroscopy, partition, pyrolysis gas and gel permeation chromatography; and thermogravimetry. Their use as quality control systems is evaluated. 33 refs. (DKG Conference on Special Quality Assurance Aspects in the Rubber Industry, Celle, Sept.1986). WEST GERMANY

Accession no.350289 Item 379 Journal of Biomedical Materials Research 21, No.3, Dec.1987, Supplement p.287-97 CORROSION AND DEGRADATION OF A PU/CONI-CR-MO PACEMAKER LEAD Pei Sung;Fraker A C US, FOOD & DRUG ADMINISTRATION; US, NATIONAL BUREAU OF STANDARDS Changes in the metal surfaces and PU (Pellethane-236380A) insulation of heart pacemaker leads under controlled in vitro conditions were investigated. The wire leads were exposed in Hank’s physiological saline solution for 14 months and analysed using SEM, X-ray energy dispersive analysis and small-angle X-ray scattering. The data obtained revealed that some leakage of solution into the leads had occurred and that changes were present on both the metal and PU surfaces. 6 refs.

FRANCE

USA

Accession no.352400

Accession no.350002

Item 377 Progress in Rubber and Plastics Technology 3, No.1, 1987, p.11-41

Item 380 Hydrocarbon Processing 66, No.10, Oct.1987, Section 1, p.39-40

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References and Abstracts

REDUCE COSTS WITH METAL BELLOWS SHAFT SEALS Martel Y;Botte J M;Regazzacci P SEALOL INC.; TORAL CFP-PARIS The replacement of elastomer seals with welded metal bellows shaft seals in the refining industry is discussed with reference to tests which claim to show large maintenance cost savings. Reasons why mechanical seals fail and methods of reducing or eliminating the major causes of mechanical seal failure are described. The cost of conversion and estimated cost recovery time is also outlined. FRANCE

Accession no.348304 Item 381 TAB: Tyres Accessories Batteries 20, No.6, Nov/Dec.1987, p.25/36 RETREADS. A TAB SPECIAL FEATURE. MORE THAN ONE LIFE A review is presented on retread tyres in the UK. Comments are given on recent reports of faulty remould tyres and the potential damage to the industry is assessed. Brief details are also given on the new equipment, processes and repair materials available to the retread industry. This information is detailed under headings for each company. BANDAG TYRE CO.; BANDVULC; BARWELL INC.; ELDEN TYRE; GRUMAC LTD.; GUMMIWERK KRAIBURG GMBH; HARLAND TYRES LTD.; MONARCH REMOULDS LTD.; MOTORWAY REMOULDS LTD.; RETYRE & RUBBER CO.LTD.; REYNER G., LTD.; TECH UK; TIP TOP INDUSTRIAL RUBBER PRODUCTS LTD.; VULTRA RUBBER CO. UK

Accession no.347662 Item 382 ASE ’85.Adhesives, Sealants & Encapsulants Conference;Day 3:Environmental Effects, Applications;Off-Shore Applications:Assembly. Kensington, London, 5-7 Nov.1985, p.52-64. 6A INTERPRETATION OF THE EFFECTS OF DIFFERENT CURING SYSTEMS ON THE WATER RESISTANCE OF POLYSULPHIDE SEALANTS Hanhela P J;Huang R H E;Paul D B;Symes T E F AUSTRALIA, DEPT.OF DEFENCE (PRI) The results are reported of a study of the disparate swell behaviour in hot water of polysulphide sealants produced with different curing agents (manganese dioxide and ammonium dichromate). Sealants tested were commercial aircraft sealants PR-1750, Pro-Seal 899 and PR-1422 and laboratory formulations prepared using Thiokol liquid

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polysulphide. The effects of type and loading of filler, crosslink densities, extraction of components by the swelling agent and chemical interaction with the swelling medium were evaluated and the part played by autoxidation assessed. 8 refs. AUSTRALIA

Accession no.347586 Item 383 Urethanes Technology 4, No.3, Sept.1987, p.37 CONSIDER THE DETAILS: QUALITY IN PU RIM PARTS Ruhmann H BATTENFELD POLYURETHANTECHNIK GMBH To manufacture good quality moulds economically, the moulder must know which parameters are important and the possibilities for assessing product quality. Several method are described of ensuring reproducibility in PU mouldings by using quantitative and qualitative methods of control; this is in effect replacing intuition by objective procedures. However, such measuring techniques and instruments cannot be used without evaluation and analysis by trained personnel. WEST GERMANY

Accession no.346856 Item 384 Kautchuk und Gummi Kunststoffe 39, No.11, Nov.1986, p.1075-81 RESIDUAL PLANT TISSUES FROM GUAYULE RUBBER PROCESSING AND THEIR EFFECT ON FAILURE PROPERTIES OF NATURAL RUBBER Bhowmick A K;Kasemsuwan S;Oroz M A;Patt J;Seeger R;MacArthur A; McIntyre D AKRON, UNIVERSITY; INDIAN INSTITUTE OF TECHNOLOGY The residual plant tissues and minerals, termed here as dirt, in guayule rubber were characterised and classified into two arbitrary groups, i.e. fine dirt and coarse dirt. The effect of these types of dirt on tensile strength and fatigue to failure properties of NR was investigated. Results are discussed and evaluated. 12 refs. INDIA; USA

Accession no.344441 Item 385 Plastverarbeiter 38, No.2, Feb.1987, p.87/94 German QUALITY CONTROL IN INJECTION MOULDING. AVOID MISTAKES IN THE FIRST PLACE Keostermann L

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WEIDMANN AG The importance of systematic defect analysis and identification of defect source or origin in quality control of injection moulding is discussed. The subject is considerd under the following headings: moulding compound specification; raw material selection and evaluation of suppliers; testing of bought raw materials; compounding; recycling of scrap; process optimisation; reliability testing; defect analysis; and microscopic studies. 9 refs. SWITZERLAND

Accession no.344359 Item 386 Polymers Paint Colour Journal 177, No.4192, 10th June 1987, p.416/8 PREVENTING BIODETERIORATION OF SURFACE COATINGS Barlow C G STERLING INDUSTRIAL COLOURS LTD. Problems associated with paint biodeterioration occurring during the manufacturing process, at the ‘in can’ stage and at the applied coating stage are discussed and the need for a long lasting biocide in paint formulations highlighted.

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Finally, criteria for selecting biocides suitable for paint formulation and its intended end use are considered. UK

Accession no.343396 Item 387 Rubber and Plastics News 17, No.5, 5th Oct.1987, p.150 SCIENTIST DISCOVERS MICROBE THAT DECOMPOSES RUBBER School R;Schreffler R A strain of bacteria that decomposes thin, soft rubber products, has been discovered by A.Tsuchii, a member of the Fermentation Research Institute of the Agency of Industrial Science & Technology in Japan. The Nocardia germ, a member of the Actinomycete group of antibioticproducing bacteria, degrades NR and synthetic polyisoprene through the digestion of micro-organisms. Brief details of degradation tests on rubber products, including gloves and bicycle tyres, are given. JAPAN, INDUSTRIAL SCIENCE & TECHNOLOGY AGENCY JAPAN; USA

Accession no.342402

© Copyright 2002 Rapra Technology Limited

Subject Index

Subject Index A ABRASION, 15 17 98 158 214 245 339 ABRASION RESISTANCE, 55 72 99 158 171 176 189 200 252 308 329 330 339 349 355 372 375 380 ABSORPTION, 3 48 82 224 240 ACCELERATED AGEING, 82 98 129 133 167 215 237 ACCELERATED TEST, 17 41 48 55 61 62 98 133 154 177 204 215 218 266 287 289 ACCELERATOR, 64 81 146 224 306 ACCIDENT, 13 32 52 132 275 ACCIDENT INVESTIGATION, 39 76 ACCIDENT PREVENTION, 78 ACETONE, 69 224 ACID ETCHING, 84 ACID RAIN, 207 211 ACID RESISTANCE, 203 368 ACRYLATE RUBBER, 26 67 176 ACRYLONITRILE-BUTADIENE COPOLYMER, 27 89 ACTIVATION ENERGY, 21 62 90 203 215 216 ADDITIVE, 8 15 33 38 42 65 69 73 81 82 97 98 99 108 115 130 133 134 135 136 145 146 154 177 178 182 183 187 188 191 201 202 213 217 218 224 225 252 262 266 306 315 334 337 353 368 ADHESION, 15 35 39 64 69 81 85 128 135 158 166 173 180 187 191 199 205 209 214 232 241 264 277 278 285 298 299 300 301 318 323 324 356 357 364 366 ADHESIVE, 15 16 69 187 199 241 269 300 307 319 323 327 329 361 373 374 ADHESIVE FAILURE, 15 ADSORPTION, 201 301 AEROSPACE APPLICATION, 6 11 44 97 226 295 362 AGEING, 3 9 15 17 21 38 48 54 60 61 64 67 81 82 95 98 115 123 126 129 133 135 144 146 164 167 176 177 189 201 203 205 207 213 215 216 217 218 219 224 235 237 241 247 252 258

262 281 287 289 297 327 354 369 376 AGGLOMERATE, 136 341 AGGREGATE, 136 341 AGGRESSIVE MEDIUM, 332 AIR BUBBLE, 178 AIR CONDITIONING, 19 115 219 225 AIR ENTRAPMENT, 178 AIR PERMEABILITY, 22 56 81 AIR POLLUTION, 112 260 AIR PRESSURE, 13 56 157 AIR SPRING, 186 AIR-INTAKE MANIFOLD, 47 AIRCRAFT, 97 226 382 AIRCRAFT TYRE, 11 53 81 244 ALGAE, 224 ALLERGY, 68 86 164 ALUMINIUM, 33 42 199 205 301 319 ALUMINIUM HYDROXIDE, 166 171 205 ALUMINIUM OXIDE, 205 380 AMINE, 65 82 192 195 203 213 AMINOLYSIS, 335 AMMONIA, 200 218 ANALYSIS, 3 8 9 18 21 35 41 44 45 47 50 51 69 79 83 84 92 98 100 106 109 114 118 126 133 134 135 144 145 154 158 161 176 177 178 182 183 188 201 202 203 204 209 216 217 218 221 236 242 252 261 268 269 273 276 283 287 289 290 316 317 322 333 341 354 378 379 384 385 ANGLE-PLY, 109 191 ANODE, 154 266 ANTIDEGRADANT, 8 65 81 146 213 377 ANTIFOULING, 367 ANTIFREEZE, 154 225 ANTIOXIDANT, 58 81 93 96 111 117 123 145 146 167 187 195 209 213 224 225 247 252 326 376 ANTIOZONANT, 15 55 73 81 96 108 135 213 224 257 315 325 343 APPEARANCE, 57 134 135 ARAMID FIBRE-REINFORCED RUBBER, 154 ARCHITECTURAL APPLICATION, 307 ARMOURED VEHICLE, 190 372

© Copyright 2002 Rapra Technology Limited

ARRHENIUS’S LAW, 17 204 ARTIFICIAL AGEING, 98 ARTIFICIAL BREAST, 88 174 210 ARTIFICIAL JOINT, 71 ASPHALT, 269 ATOMIC FORCE MICROSCOPY, 128 ATTENUATED TOTAL REFLECTION SPECTROSCOPY, 69 98 173 AUGER SPECTROSCOPY, 301 AUTOMATION, 51 57 106 167 217 AUTOMOTIVE APPLICATION, 13 19 42 47 49 58 61 79 80 103 114 115 130 146 154 170 183 219 222 225 230 243 270 316 328 335 344 346 368 376 AUTOMOTIVE HOSE, 154 219 266 AUTOXIDATION, 153 195 213 262 382

B BACTERIA, 224 231 331 351 387 BALL, 22 BALLOON, 22 BARRIER PROPERTIES, 86 131 164 228 229 BEAD, 245 286 BEARING, 51 182 230 292 296 BELLOWS, 380 BELT, 10 103 107 110 121 140 147 156 158 172 BENDING, 158 176 190 BIAS TYRE, 151 BICYCLE TYRE, 387 BIOCIDE, 224 367 386 BIOCOMPATIBILITY, 164 BIODEGRADATION, 9 122 153 159 174 209 224 231 248 249 306 320 331 351 386 BIOLOGICAL ATTACK, 17 96 122 224 249 261 306 320 331 351 367 387 BIOMEDICAL APPLICATION, 238 352 BLADDER, 22 BLEACHING, 33 BLEND, 64 73 81 128 130 134 135 146 158 171 177 200 213 220 225 283 345 367 BLISTERING, 33 82 142 178 202

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Subject Index

204 219 290 353 BLOOM, 8 55 58 64 135 213 322 BLOW-OUT, 77 291 337 BOAT, 265 BODY PANEL, 222 BOILING WATER, 203 BOND STRENGTH, 6 34 277 300 357 366 BONDING, 15 16 59 69 81 97 160 169 180 205 220 261 300 323 357 361 BONDING AGENT, 15 16 69 241 269 373 BOOT, 200 BOVINE SERUM, 271 BRAKE LINING, 80 BRAKING, 177 BREAKAGE, 5 235 258 BREAKER, 4 177 BREAKING STRENGTH, 50 137 324 BREAKING STRESS, 133 163 BRIDGE BEARING, 340 BRITTLENESS, 195 218 269 297 BROMOBUTYL RUBBER, 81 135 177 343 BUBBLE, 178 184 202 BUCKLING, 79 BUILDING APPLICATION, 38 60 129 232 269 296 298 299 307 319 323 374 BULGING, 158 BURST STRENGTH, 101 164 165 167 258 291 321 350 BURSTING, 53 101 116 189 BUS TYRE, 7 14 83 BUSHING, 47 137 190 339 345 BUTADIENE-ACRYLONITRILE COPOLYMER, 22 23 27 30 41 45 51 55 67 73 75 82 86 89 93 98 121 125 176 182 184 195 200 201 202 203 213 218 219 220 224 225 226 239 257 263 268 272 276 284 290 291 332 335 338 339 342 345 348 349 354 368 372 BUTADIENE RUBBER, 6 45 74 81 98 111 134 135 136 158 195 262 291 304 337 BUTADIENE-STYRENE COPOLYMER, 37 50 75 98 99 158 163 171 195 201 213 218 220 224 246 247 252 291 337 339 340 342 376 BUTYL RUBBER, 22 23 67 73 79 81 108 130 135 177 195 213 218 222 224 291 319 337 343 354

96

C CABLE, 73 133 253 CALCIFICATION, 152 194 352 CALCIUM CARBONATE, 99 133 154 236 306 382 CALCULATION, 118 160 161 162 186 206 236 243 246 256 261 340 CALENDERING, 136 178 200 CALIBRATION, 84 85 167 183 217 363 CAMERA, 51 CAP PLY, 52 CAR, 1 13 146 154 183 219 376 CAR TYRE, 39 77 78 81 87 114 177 189 191 314 328 CARBON BLACK, 8 26 37 42 50 58 69 81 98 99 108 123 133 134 135 136 144 154 173 177 181 182 191 201 202 224 236 252 266 306 340 364 366 382 CARBON DIOXIDE, 202 204 208 338 358 CARBOXYLATED RUBBER, 368 CARCASS, 97 CARCINOGEN, 88 CARDIAC PACEMAKER, 166 CASE HISTORY, 23 38 47 71 129 CASING, 72 157 314 CATERPILLAR TRACK, 155 190 220 345 372 CATHETER, 71 CAVITATION, 69 178 180 214 259 285 CELL GROWTH, 209 CELLULAR MATERIAL, 36 255 270 318 CHAIN SCISSION, 10 133 135 195 213 343 352 CHARACTERISATION, 8 25 45 47 143 153 161 205 209 301 311 354 384 CHEMICAL CLEAVAGE, 233 343 CHEMICAL DEGRADATION, 9 10 48 82 335 CHEMICAL INDUSTRY, 120 380 CHEMICAL PROPERTIES, 15 16 21 42 48 54 61 82 93 115 117 125 148 154 CHEMICAL RESISTANCE, 15 16 19 21 42 44 48 54 55 61 73 75 81 82 93 95 117 124 125 134 135 146 148 154 189 200 203 204 212 218 219 226 238 239 240 248 251 261 268 276 332 335 338 352 354 355 368 376 CHEMICALLY RESISTANT

APPLICATION, 200 203 204 218 219 CHLORAMINE, 93 117 218 CHLORINATED POLYETHYLENE, 290 332 338 CHLORINATED RUBBER, 69 233 367 CHLOROBUTYL RUBBER, 135 343 CHLOROPRENE RUBBER, 22 64 67 73 86 195 225 239 273 278 290 315 323 332 338 340 CHLOROSULPHONATED POLYETHYLENE, 6 133 CHROMATOGRAPHY, 8 43 65 135 143 144 153 CITRACONIMIDOMETHYL BENZENE, 97 CLADDING, 299 CLEANING, 64 189 211 CLEANING AGENT, 207 CLEANLINESS, 113 CLOSURE, 47 CLOTHING, 138 CLUTCH, 243 COATED FABRIC, 198 200 276 278 284 317 318 324 COATING, 15 33 38 64 112 222 224 233 264 276 279 324 386 COEFFICIENT OF FRICTION, 141 158 189 COHESION, 2 15 31 199 285 299 341 COHESIVE FAILURE, 139 173 COLOUR, 135 189 213 COLOUR RETENTION, 111 COMPATIBILITY, 19 66 125 134 276 374 COMPOSITE, 9 35 81 85 109 121 139 154 162 191 222 329 335 COMPOUND, 15 42 64 67 81 97 123 134 136 144 146 177 181 188 201 217 224 243 252 266 COMPOUNDING, 15 37 43 47 92 112 123 134 136 144 145 146 147 155 178 200 212 213 217 219 224 234 247 252 385 COMPOUNDING INGREDIENT, 8 221 306 334 COMPRESSION, 31 36 82 129 158 180 182 183 190 201 202 287 291 316 347 348 COMPRESSION MOULDING, 145 146 178 COMPRESSION PROPERTIES, 82 126 141 146 184 204 222 255 287 291 297 316 347 348

© Copyright 2002 Rapra Technology Limited

Subject Index

COMPRESSION SET, 44 63 82 93 146 154 219 253 255 297 COMPRESSION STRESS, 82 146 190 COMPRESSION STRESS RELAXATION, 44 45 COMPUTER AIDED ANALYSIS, 51 79 83 84 182 270 COMPUTER AIDED DESIGN, 18 246 COMPUTER AIDED PROCESS CONTROL, 217 COMPUTER AIDED QUALITY CONTROL, 51 83 COMPUTER AIDED TESTING, 47 85 177 183 COMPUTER MODEL, 47 79 144 237 276 CONDOM, 22 25 101 116 131 164 165 167 228 229 258 271 321 CONNECTOR, 47 79 CONSTRUCTION, 296 307 CONSUMER PROTECTION, 293 CONTAMINATION, 15 71 112 113 137 163 214 233 304 320 384 CONTRACEPTIVE, 22 25 101 116 131 164 165 228 229 258 271 321 CONTROL EQUIPMENT, 127 177 217 246 363 371 CONVEYOR BELT, 10 158 317 COOLANT, 42 154 225 266 COOLER HOSE, 154 219 266 COPPER, 213 319 326 CORD, 139 156 162 267 CORROSION, 23 56 154 205 357 379 CORROSION INHIBITOR, 82 154 CORROSION RESISTANCE, 15 48 124 169 233 276 284 357 379 380 COST, 5 20 54 59 86 91 127 162 200 204 222 245 246 254 295 380 CRACK GROWTH, 46 50 54 61 69 74 81 95 100 121 134 139 154 160 161 177 182 184 195 197 202 218 256 257 259 261 266 267 316 332 340 372 CRACK INITIATION, 95 139 154 202 CRACK LENGTH, 134 139 177 202 CRACK RESISTANCE, 55 95 134 177 CRACKING, 22 24 35 37 42 46 64 69 70 74 79 81 93 95 98 109

121 128 134 135 139 146 154 167 177 182 188 191 200 202 204 213 218 219 256 257 261 315 316 338 353 CREASING, 189 CREEP, 17 61 158 191 193 243 259 288 316 340 CREEP RUPTURE, 307 323 CREPE RUBBER, 164 CRITICAL PRESSURE, 202 CROSS PLY TYRE, 151 177 CRYSTALLISATION, 37 69 71 136 145 340 CURE, 173 246 297 340 CURE RATE, 15 81 144 146 178 185 CURE TIME, 58 69 134 145 163 177 200 213 217 CURING, 15 28 42 64 70 73 122 173 188 195 252 255 280 297 334 340 CURING AGENT, 8 37 69 81 82 117 133 135 144 145 154 164 178 188 192 213 218 224 262 306 334 337 377 382 CURING TEMPERATURE, 15 69 134 145 178 200 280 CURVATURE, 156 CUSHION GUM, 177 CUT GROWTH, 4 81 134 145 177 CUT RESISTANCE, 4 134 145 177 189 339 CUTTING, 158 171 200 217 CYCLIC DEFORMATION, 134 156 CYCLIC LOADING, 46 148 162 191 297 340 CYTOTOXICITY, 224

D DAMAGE, 3 11 34 39 41 42 63 77 78 84 85 155 156 183 184 189 191 202 244 247 252 253 254 294 296 350 375 DAMAGE DETECTION, 40 252 DAMAGE TOLERANCE, 254 DAMPING, 79 130 146 183 190 259 296 DEBONDING, 15 52 139 191 205 DECOMPOSITION PRODUCT, 291 337 DECOMPRESSION, 3 184 202 204 208 DEFECT, 5 8 15 20 25 26 27 28 29 30 51 57 71 83 85 92 100 106 116 134 145 178 188 201 221 228 229 231 232 245 264 265

© Copyright 2002 Rapra Technology Limited

274 285 286 309 310 320 322 330 333 346 353 385 DEFECTIVE SAMPLE, 265 DEFLATION, 11 DEFORMATION, 15 48 82 110 134 136 139 145 156 158 169 176 180 182 183 186 188 201 204 215 216 243 259 264 267 287 288 291 294 317 337 347 348 353 DEGRADATION, 3 9 10 15 17 21 33 37 38 41 42 44 48 49 54 60 61 63 64 67 74 81 82 93 95 96 98 115 122 123 124 126 129 133 135 144 146 153 154 168 195 208 213 215 216 218 231 233 234 248 249 252 258 262 263 266 280 281 287 289 297 327 352 354 356 369 376 379 380 DEGRADATION PRODUCT, 98 133 DEGRADATION RATE, 98 167 213 215 DEHYDROCHLORINATION, 133 DEHYDROHALOGENATION, 69 DELAMINATION, 4 57 84 85 109 147 191 299 DENTAL APPLICATION, 175 DEPROTEINISATION, 69 145 DEPTH PROFILING, 215 216 DESICCANT, 93 178 DESIGN, 3 18 23 24 39 54 66 89 126 139 140 141 147 161 169 183 190 192 198 206 214 234 243 260 276 281 307 319 330 339 355 362 DETERGENT, 15 376 DETERGENT RESISTANCE, 326 DETERIORATION, 37 64 DIAPHRAGM, 18 19 23 47 101 198 218 DIELECTRIC PROPERTIES, 84 200 268 DIENE RUBBER, 64 98 171 262 315 325 DIFFERENTIAL SCANNING CALORIMETRY, 43 143 185 248 369 DIFFERENTIAL THERMAL ANALYSIS, 43 143 185 248 369 DIFFUSION, 21 31 70 135 178 179 202 215 216 237 256 257 269 290 DIGITAL IMAGE ANALYSIS, 83 DIMENSION, 51 81 106 139 190 201

97

Subject Index

DIMETHYLMERCURY, 132 DIP MOULDING, 164 DIPPING, 15 22 64 DIRT CONTENT, 384 DISCOLOURATION, 33 68 108 111 123 135 167 189 195 213 223 269 318 327 DISHWASHER, 79 DISINFECTANT, 218 DISPERSION, 8 26 134 136 163 178 201 252 367 376 DISPLACEMENT, 156 177 182 183 190 191 DISTORTION, 5 218 DRAINAGE, 224 DRAINAGE PIPE, 96 DRIVE BELT, 110 DRYING, 15 178 195 207 326 DURABILITY, 4 7 14 31 37 38 49 50 52 81 129 152 169 215 216 237 240 297 300 316 366 DUROMETER, 163 217 DYNAMIC FATIGUE, 280 DYNAMIC LOADING, 98 DYNAMIC MECHANICAL PROPERTIES, 143 144 146 176 183 201 225 259 DYNAMIC MODULUS, 126 144 171 176 183 356 364 DYNAMIC PROPERTIES, 17 130 143 144 146 DYNAMIC SEAL, 23 66 176

E EARTHQUAKE, 215 216 ECCENTRICITY, 176 ELASTIC MODULUS, 79 158 176 188 192 202 218 316 348 ELASTIC PROPERTIES, 21 92 136 144 158 164 ELASTIC RECOVERY, 2 176 225 ELASTICITY, 82 133 141 144 158 163 167 176 177 182 193 218 236 350 ELECTRICAL APPLICATION, 270 ELECTRICAL CONDUCTIVITY, 154 181 200 ELECTRICAL CONNECTOR, 47 79 ELECTRICAL INSULATION, 73 379 ELECTRICAL INSULATOR, 112 ELECTRICAL PROPERTIES, 73 84 90 116 148 154 200 266 268 ELECTRICAL RESISTIVITY, 84 154

98

ELECTRICAL STRESS, 17 ELECTROCHEMICAL DEGRADATION, 9 42 154 266 366 ELECTRODEPOSITION, 15 ELECTROLYTIC RESISTANCE, 357 ELECTROMAGNETIC, 23 84 183 ELECTRON MICROSCOPY, 33 154 ELECTRON PROBE MICROANALYSIS, 253 ELECTROSTATIC, 181 ELEMENTAL ANALYSIS, 8 ELONGATION, 58 93 111 133 144 145 146 154 163 176 195 201 215 216 218 219 258 341 ELONGATION AT BREAK, 50 65 133 136 154 167 252 324 326 376 ELUENT, 153 EMBRITTLEMENT, 297 EMISSION, 19 EMISSION CONTROL, 1 260 ENDURANCE, 190 ENERGY CONSUMPTION, 13 14 42 157 217 328 ENERGY DENSITY, 46 177 182 ENERGY DISPERSIVE X-RAY ANALYSIS, 69 269 277 ENERGY DISSIPATION, 98 145 158 169 177 ENERGY RELEASE RATE, 46 118 134 139 ENERGY STORAGE, 82 182 193 350 ENGINE, 225 ENGINE MOUNTING, 47 49 61 64 130 146 ENGINEERING APPLICATION, 61 129 137 160 251 259 307 340 ENVIRONMENT, 17 138 235 251 368 ENVIRONMENTAL RESISTANCE, 38 112 ENVIRONMENTAL STRESS CRACKING, 9 154 159 209 248 352 ENZYMATIC DEGRADATION, 224 EPICHLOROHYDRIN RUBBER, 23 368 EPOXIDISED NR, 99 257 EQUIPMENT, 12 20 57 77 148 158 171 254 262 381 EROSION, 214 ETCHING, 84

ETHYLENE-PROPYLENE COPOLYMER, 23 84 93 195 213 348 354 ETHYLENE-PROPYLENEDIENE TERPOLYMER, 23 41 42 45 58 60 64 79 92 93 108 115 117 134 135 154 195 200 205 213 218 224 239 269 323 340 EXAMINATION GLOVE, 138 EXPANSION, 82 90 EXPLOSION, 275 291 337 EXPLOSIVE DECOMPRESSION, 3 23 82 125 178 202 212 219 225 234 237 238 239 240 272 276 282 290 358 360 368 EXPOSURE TIME, 82 98 133 146 154 176 207 218 224 252 EXTENSION, 129 145 182 225 324 EXTRACTABILITY, 279 EXTRACTION, 69 98 133 224 225 EXTRUSION, 59 63 82 92 93 124 136 178 188 201 227 237 251 254 274 285 368 EXTRUSION FAULT, 92 188

F FABRIC, 57 318 FABRIC REINFORCED, 18 FACE SEAL, 23 FAIL SAFE, 286 FAILURE ANALYSIS, 7 8 10 14 16 19 32 35 38 40 45 49 59 66 71 85 87 91 102 103 104 110 114 121 220 242 243 254 270 301 346 365 FAILURE MECHANISM, 18 69 85 102 103 104 110 114 121 139 332 FAILURE MODE AND EFFECT ANALYSIS, 59 FATIGUE, 17 37 40 46 50 81 85 100 102 103 104 128 134 137 139 144 145 146 148 152 156 157 161 162 171 172 177 182 183 189 190 191 194 195 213 235 243 244 259 261 267 307 317 344 358 369 370 384 FATIGUE STRENGTH, 35 102 103 104 FAULT, 26 27 28 29 30 114 286 FAULT DETECTOR, 51 FAULT DIAGNOSIS, 26 27 28 29 30 51 83 114 185 FIBRE-REINFORCED RUBBER, 81 85 121 139 154 267 345

© Copyright 2002 Rapra Technology Limited

Subject Index

FILLED, 69 82 173 182 183 201 366 FILLER, 8 22 26 37 50 58 69 75 81 98 99 112 117 121 133 134 135 136 144 154 163 173 177 178 182 183 188 191 201 202 213 217 218 224 225 236 252 266 306 340 353 356 364 366 377 382 FILM, 69 98 131 145 148 228 FINITE ELEMENT ANALYSIS, 3 18 35 44 45 47 79 100 109 118 158 161 182 183 186 202 204 206 216 243 294 FIRE HAZARD, 181 FISH-EYES, 15 FLAMMABILITY, 200 275 FLASH POINT, 226 FLAW, 131 134 137 145 163 175 184 202 228 264 265 274 285 286 309 310 319 320 322 330 333 346 353 385 FLEX CRACK, 111 195 213 FLEXIBLE, 3 10 60 223 FLEXURAL PROPERTIES, 37 61 81 82 111 139 146 156 158 163 167 176 177 180 182 183 189 190 259 278 324 FLEXURE, 278 FLUID RESISTANCE, 141 203 225 238 240 FLUID TIGHT, 19 FLUOROELASTOMER, 1 28 30 31 45 51 82 125 176 184 202 204 212 218 225 238 239 240 253 290 334 348 353 360 362 368 376 FLUOROSILICONE RUBBER, 23 226 368 FOAM, 36 223 232 255 270 318 FOOD APPLICATION, 192 198 FOOTWEAR, 200 318 324 327 FORCE, 79 82 139 146 158 177 183 188 191 FORENSIC ANALYSIS, 12 87 FORMIC ACID, 154 FORMULATION, 2 42 43 45 58 73 93 111 117 128 130 147 192 240 241 282 283 386 FOURIER TRANSFORM, 69 98 144 145 153 183 194 242 269 273 335 FRACTURE, 4 15 37 69 82 109 136 139 160 178 182 184 201 202 256 267 288 290 332 338 358 FRACTURE MECHANICS, 35 46 118 139 182 184 202 237 267

FRACTURE MORPHOLOGY, 128 FRACTURE SURFACE, 69 100 FREE RADICAL, 195 315 342 FREQUENCY, 84 85 130 144 146 176 177 183 188 191 201 FRICTION, 23 79 158 FRICTION PROPERTIES, 141 158 189 225 FUEL HOSE, 1 80 FUEL LINE, 226 FUEL RAIL, 80 FUEL RESISTANCE, 19 44 225 FUEL SYSTEM, 1 19 226 FUEL TANK, 279 FUNGAL RESISTANCE, 224

G GAMMA IRRADIATION, 342 GAS, 3 17 56 82 184 202 204 239 263 272 290 338 GAS CHROMATOGRAPHY, 43 143 167 378 GAS DECOMPRESSION, 184 GAS DIFFUSION, 31 153 178 202 GAS INDUSTRY, 272 360 368 GAS PERMEABILITY, 19 31 56 184 197 202 216 219 237 239 240 263 272 338 358 GAS SOLUBILITY, 31 202 GASES, 3 17 56 82 GASKET, 45 93 94 218 225 251 292 348 GASOLINE, 225 GEL, 69 88 144 195 201 210 247 252 367 GEL PERMEATION CHROMATOGRAPHY, 143 144 153 378 GENERAL RUBBER GOODS, 185 GEOMETRY, 92 98 182 190 240 GLAND, 44 218 GLASS FIBRE-REINFORCED RUBBER, 121 GLASS TRANSITION TEMPERATURE, 22 31 58 143 185 202 204 257 348 GLAZING, 211 307 319 GLOSS, 92 135 200 GLOVE, 22 86 101 131 132 138 148 164 175 229 387 GRAVIMETRIC ANALYSIS, 21 43 113 133 143 GROOVE, 158 319 GUAYULE, 145 384 GUM, 201

© Copyright 2002 Rapra Technology Limited

H HALOBUTYL RUBBER, 108 135 354 HARDNESS, 2 17 58 93 111 117 133 144 146 154 163 183 188 203 204 217 218 219 225 340 370 376 HEALTH HAZARD, 86 88 119 132 138 174 210 242 286 293 377 HEART PACEMAKER, 379 HEART VALVE, 152 194 HEAT AGEING, 15 62 81 90 111 130 133 135 144 146 195 203 213 215 216 217 218 219 252 297 316 326 HEAT BUILD-UP, 144 177 259 337 HEAT DEGRADATION, 6 29 49 62 64 90 98 133 158 HEAT RESISTANCE, 2 4 29 81 130 146 176 192 204 219 240 247 261 266 312 355 376 HEATER HOSE, 266 HEAVY VEHICLE TYRE, 4 7 10 20 40 56 72 76 77 78 81 83 85 91 142 151 157 280 286 314 HEEL, 200 HIGH PERFORMANCE LIQUID CHROMATOGRAPHY, 43 242 HIGH PERFORMANCE TYRE, 52 177 HIGH PRESSURE, 3 18 19 202 239 272 276 290 338 HIGH SPEED TYRE, 52 151 245 HIGH TEMPERATURE, 3 124 133 176 203 225 227 247 252 257 338 HOLE, 25 92 175 HOLOGRAPHY, 245 HOSE, 1 19 42 47 79 80 113 115 154 206 219 225 235 266 276 281 284 350 HOT AIR AGEING, 144 146 HOT WATER, 261 271 382 HUMIDITY, 167 205 224 HYDRAULIC, 214 HYDRAULIC FLUID, 113 HYDRAULIC HOSE, 369 HYDROCHLORIC ACID, 69 133 203 HYDROCHLORINATION, 96 HYDROGEN PEROXIDE, 98 143 154 213 248 266 HYDROGEN SULFIDE, 203 204 235 282 368 HYDROGENATED NBR, 1 23 82 121 125 176 184 203 212 219

99

Subject Index

224 225 272 276 282 HYDROLYSIS, 70 154 203 213 279 HYDROPHOBIC, 112 HYPOCHLORITE, 218 HYSTERESIS, 81 134 145 191 259 267

K KNIT LINE, 232

L

IMAGING, 51 83 84 262 IMMERSION, 82 154 176 203 219 224 367 376 379 382 IMPACT PROPERTIES, 12 34 158 183 317 IMPLANT, 71 88 152 166 174 194 210 231 331 352 379 IMPURITIES, 145 IN-VITRO, 116 153 159 194 248 IN-VIVO, 209 248 INCLUSION, 28 29 INDUSTRIAL HAZARD, 132 INFLATION, 164 167 INFLATION PRESSURE, 34 39 81 85 105 189 191 286 294 314 INJECTION MOULDING, 246 270 346 385 INNER TUBE, 189 INSERT, 137 190 INSPECTION, 51 57 83 85 129 170 254 371 INSPECTION SYSTEM, 106 127 INSTALLATION, 23 214 INSULATION, 6 49 181 284 307 INTERFACE, 6 69 134 173 205 264 301 INTERFACIAL ADHESION, 191 241 INTERFACIAL DEBONDING, 15 INTERFACIAL PROPERTIES, 35 173 209 322 INTERFACIAL STRENGTH, 277 IR SPECTROSCOPY, 43 69 143 145 153 173 203 242 248 269 273 335 378 IRIDESCENCE, 58 IRON, 203 213 IRON OXIDE, 356 364 IRRADIATION DEGRADATION, 342 ISOBUTYLENE COPOLYMER, 108 130 134 135 146 ISOPRENE RUBBER, 68 69 98 144 145 290 304 387

LAMINATE, 109 139 198 234 276 366 LAMP, 71 LASER, 25 57 127 135 333 LATCH, 79 LATEX, 8 22 68 86 101 116 131 132 138 148 164 167 170 175 228 229 249 258 271 275 321 326 LAWSUIT, 39 52 71 76 132 275 LEACH, 218 LEAD OXIDE, 82 133 LEAK DETECTION, 25 349 LEAKAGE, 1 19 22 44 47 56 79 80 82 94 112 113 115 116 154 164 174 176 181 210 226 229 260 266 271 275 287 292 349 379 LEAKPROOF, 200 LEATHER, 200 327 LEGISLATION, 20 32 88 91 115 119 157 170 174 189 210 260 265 293 309 310 LIABILITY, 39 76 119 LIFEBOAT, 265 LIFETIME PREDICTION, 38 44 46 49 82 85 98 129 208 LIGHT DEGRADATION, 9 98 207 261 326 LINER, 6 LINING, 264 276 369 LIP SEAL, 44 176 LIQUID ABSORPTION, 82 LIQUID CHROMATOGRAPHY, 43 65 135 268 LITIGATION, 39 52 71 76 132 275 LOADING, 6 11 34 35 60 98 105 137 139 146 177 180 182 183 190 191 211 218 288 314 370 LORRY TYRE, 20 72 157 LOW PRESSURE, 330 LOW TEMPERATURE, 176 225 247 257 368 LOW TEMPERATURE PROPERTIES, 22 81 82 89 124 189 204 219 261 347 LUBRICANT, 15 22 25 165 167 176 219 225 376

J

M

JOINT, 79 96 129 307 323 349 370 376

MACROGEL, 201 MACROPHAGE, 209

I

100

MAINTENANCE, 57 72 127 189 200 217 330 375 MANIFOLD, 47 MARINE APPLICATION, 193 265 278 367 MASS SPECTROSCOPY, 43 69 135 MATERIAL REPLACEMENT, 38 55 68 86 135 212 222 241 254 372 373 380 MATERIALS SELECTION, 19 23 42 54 66 117 140 141 204 224 225 254 261 298 368 385 386 MATHEMATICAL MODEL, 41 50 186 204 217 236 243 256 261 287 289 290 316 317 341 MECHANICAL DEGRADATION, 227 MECHANICAL PART, 51 82 94 176 182 190 193 202 203 204 218 219 224 349 368 376 MECHANISM, 98 102 103 107 133 153 154 156 168 171 173 180 206 207 213 220 263 264 272 315 325 329 335 338 342 343 348 352 358 MEDICAL APPLICATION, 25 71 138 165 229 248 258 271 321 331 352 379 MEMBRANE, 31 60 93 148 179 269 MEMORY EFFECT, 82 183 METAL, 15 42 51 69 154 180 182 199 213 243 261 300 301 347 348 357 366 367 379 380 METAL ADHESION, 15 220 METAL CORROSION, 56 METAL FIBRE-REINFORCED RUBBER, 81 85 369 METAL INSERT, 190 METAL ION, 203 352 METHANE, 82 202 208 272 METHANOL, 208 225 368 METHYLSTYRENE COPOLYMER, 108 130 134 135 146 MICROBIOLOGICAL ATTACK, 96 122 224 249 306 387 MICROCRACK, 98 100 154 218 MIGRATION, 15 55 56 69 98 112 133 134 135 213 224 MILITARY APPLICATION, 155 190 193 220 265 278 308 312 339 372 MILLING, 28 136 178 200 MINER’S RULE, 50 MINING APPLICATION, 71 MISSILE, 193 MIXING, 15 26 39 59 92 99 117

© Copyright 2002 Rapra Technology Limited

Subject Index

134 136 144 145 146 176 178 192 195 200 201 217 246 252 255 334 341 383 MODEL, 18 70 134 144 153 158 161 182 183 204 207 209 215 217 246 258 263 267 331 344 MODEL COMPOUND, 248 258 263 267 331 343 344 MODULUS, 58 81 82 93 111 136 139 141 144 145 146 154 158 163 177 178 195 201 202 219 253 290 342 364 376 MOISTURE RESISTANCE, 112 207 222 MONITORING, 13 20 72 127 281 313 MOONEY SCORCH, 111 136 146 MOONEY VISCOSITY, 81 92 136 144 177 188 195 247 252 MOULD GROWTH, 320 MOULDING, 15 59 82 145 146 190 246 334 383 MOULDING FAULT, 346 MOUNTING, 79 182 259

N NATURAL RUBBER, 10 21 22 23 50 55 64 65 67 68 69 75 81 86 96 97 98 99 101 111 122 130 131 134 135 136 137 143 144 145 146 158 163 164 167 170 171 175 182 185 195 200 213 215 216 218 220 224 241 243 246 249 257 273 288 291 304 306 326 332 337 338 339 340 345 351 366 384 387 NEOPRENE, 64 67 73 86 195 278 NITRILE RUBBER, 22 23 27 30 41 45 51 55 67 73 82 86 89 93 98 125 176 182 184 195 200 201 202 203 213 218 219 220 224 225 226 239 257 263 268 290 291 332 335 338 339 342 345 348 349 354 368 372 NITROGEN, 56 202 NITROGEN PERMEABILITY, 56 NITROSAMINE, 242 NOISE ABATEMENT, 245 NON-DESTRUCTIVE TESTING, 10 40 57 84 85 218 245 262 281 333 NON-STAINING, 108 111 135 213 325 NUCLEAR MAGNETIC RESONANCE, 10 43 69 201 242 283 NYLON, 52 115 151

O O-RING, 23 44 51 66 82 93 126 141 163 196 202 203 208 218 225 226 251 254 292 ODOUR, 68 224 OFF-THE-ROAD TYRE, 81 OFFSHORE APPLICATION, 3 54 82 124 125 204 238 276 284 332 358 360 369 OIL, 81 133 134 135 146 176 224 235 239 259 338 OIL DRILLING, 212 276 282 360 368 OIL EXTENSION, 15 81 134 135 201 224 OIL HOSE, 284 OIL INDUSTRY, 54 184 302 368 OIL RECOVERY, 82 202 203 204 238 240 281 282 284 369 OIL REMOVAL, 15 OIL RESISTANCE, 44 124 176 200 203 204 212 219 225 239 261 268 368 369 376 OIL SEAL, 125 176 184 202 203 204 349 OIL SWELL, 176 ON-LINE INSPECTION SYSTEM, 40 85 OPTICAL MICROSCOPY, 33 84 92 134 OPTICAL PROPERTIES, 74 92 135 139 145 188 189 213 262 OPTICAL SENSOR, 84 OPTIMISATION, 47 110 220 294 344 OPTOELECTRONIC DEVICE, 5 ORANGE PEELING, 92 ORGANOLEPTIC PROPERTIES, 224 ORGANOSILOXANE POLYMER, 70 126 OVEN AGEING, 133 144 OVERCURE, 353 OVERINFLATION, 189 OXIDATION, 4 9 10 15 56 64 98 154 159 185 195 203 211 215 216 253 259 261 262 288 326 342 OXIDATION RESISTANCE, 167 355 OXIDATIVE DEGRADATION, 4 10 15 56 64 98 133 154 159 185 195 203 213 215 216 218 252 259 261 262 288 326 342 OXYGEN, 64 153 187 195 199 224 288 OXYGEN ABSORPTION, 195

© Copyright 2002 Rapra Technology Limited

215 216 OXYGEN PERMEABILITY, 167 216 OZONE, 17 64 75 95 98 177 187 195 OZONE CRACKING, 55 73 75 95 98 130 134 146 163 200 213 326 OZONE DEGRADATION, 58 65 74 75 95 98 99 108 135 168 189 211 213 241 257 259 273 315 325 326 342 343 OZONE RESISTANCE, 55 73 75 81 95 134 135 146 200 213 261 OZONOLYSIS, 10 213 343

P PACKAGING, 167 PAINT, 233 367 386 PALE CREPE, 164 PASSENGER TYRE, 11 13 20 32 72 81 177 181 189 PEEL STRENGTH, 69 173 180 199 241 264 277 PEELING, 34 323 PENETRATION, 116 PERCOLATION, 197 256 PERMANENT SET, 144 154 176 340 355 PERMEABILITY, 1 19 22 29 31 48 54 56 81 101 131 148 166 177 197 202 204 263 PERMEATION, 19 132 202 219 276 284 358 PEROXIDE, 42 98 117 154 188 213 218 PEROXIDE VULCANISATION, 93 154 188 PH, 154 166 207 211 218 225 PHARMACEUTICAL APPLICATION, 238 PHENYLENE DIAMINE, 75 135 213 315 PHOSPHITE, 135 195 213 PHOTODEGRADATION, 98 213 PHOTOLYSIS, 98 PHOTOOXIDATION, 9 PHOTOOXIDATIVE DEGRADATION, 98 PHYSICAL PROPERTIES, 22 37 64 97 123 125 130 163 169 207 211 212 220 255 279 PIPE, 38 47 71 79 96 PIPE FITTING, 96 224 351 360 PIPELINE, 3 PLAQUE, 133 PLASTICISER, 8 15 133 178 218

101

Subject Index

224 351 PLUMBING APPLICATION, 218 224 PLY SEPARATION, 4 40 139 PNEUMATIC TYRE, 293 POLLUTION, 37 112 260 POLYACETAL, 38 71 POLYACRYLATE, 23 26 67 368 POLYAMIDE, 52 115 151 POLYARAMIDE, 18 POLYBUTADIENE, 6 45 74 81 98 111 134 135 136 158 171 173 195 213 247 252 262 304 337 POLYBUTYLENE, 71 POLYCHLOROPRENE, 22 64 67 73 86 195 200 213 218 219 224 225 239 273 315 332 338 340 POLYDIMETHYL SILOXANE, 112 179 188 256 POLYESTER URETHANE, 159 192 327 POLYETHER URETHANE, 152 159 192 194 209 248 364 379 POLYETHER URETHANE UREA, 152 153 209 POLYETHYLENE, 58 71 133 253 POLYETHYLENE TEREPHTHALATE, 335 POLYISOPRENE, 68 69 98 144 145 195 213 224 227 290 304 387 POLYSILOXANE, 70 126 285 POLYSULFIDE, 23 67 129 382 POLYURETHANE, 2 16 30 36 129 140 152 158 163 164 183 192 194 223 232 263 307 318 324 327 352 356 361 369 379 383 POLYURETHANE ELASTOMER, 30 153 158 173 183 248 279 327 356 361 364 POLYVINYL CHLORIDE, 60 71 73 86 132 POROSITY, 36 134 148 159 178 228 POST CURING, 82 167 176 216 224 297 POTABLE WATER, 218 224 351 354 POWER STEERING, 225 POWER TRANSMISSION, 112 POWER TRANSMISSION BELTING, 107 110 140 147 172 PRECISION, 51 127 161 217 378 PRESSURE, 3 11 13 20 31 72 78 82 92 94 136 144 154 158 167 178 183 184 188 191 197 202 204 212 225 226 238 263 272

102

285 330 338 350 358 PRESSURE DROP, 158 PRESSURE HOSE, 369 PRESSURE LOSS, 82 PRESSURE RESISTANCE, 18 204 PRESSURE SENSOR, 92 PRIMER, 15 69 205 PROBLEM PREVENTION, 15 16 22 26 27 28 29 30 43 71 142 217 221 242 254 255 283 298 302 318 328 334 336 359 361 374 386 PROBLEM SOLVING, 26 27 28 29 30 PROCESSING, 4 15 26 27 28 29 39 57 115 127 178 192 246 247 252 274 285 334 384 PRODEGRADANT, 387 PRODUCT DESIGN, 139 183 190 238 240 259 289 298 299 334 PRODUCT DEVELOPMENT, 47 79 PRODUCT LIABILITY, 39 76 119 170 265 309 310 PRODUCT RECALL, 20 39 PROPELLANT, 193 275 PROSTHESIS, 152 159 166 194 210 231 PROTECTIVE CLOTHING, 276 PROTECTIVE COATING, 38 PROTOTYPE, 11 59 79 85 190 PSEUDOMONAS, 224 PULLEY, 158 172 PUMP, 92 113 260 PUNCTURE, 25 77 116 189 275 PUNCTURE RESISTANCE, 81 116 PURITY, 37 68 145 PYROLYSIS, 185

Q QUALITY, 44 57 59 119 120 295 371 QUALITY ASSURANCE, 116 120 144 170 245 283 295 303 311 313 363 365 371 378 QUALITY CIRCLE, 295 363 QUALITY CONTROL, 38 44 51 83 85 101 106 116 120 127 143 144 161 164 200 201 217 232 242 246 255 265 270 283 289 295 303 304 305 311 313 336 346 359 363 365 371 373 374 377 378 383 385 QUALITY MANAGEMENT, 101 120 170

R RADIAL PLY TYRE, 11 40 53 81 83 85 177 191 330 RADIAL SEAL FORCE, 44 RADIAL TYRE, 11 40 53 81 83 85 330 RADIATION DEGRADATION, 168 RADIATOR, 42 RADIATOR HOSE, 154 266 RAIL PAD, 79 RAILWAY, 370 RAILWAY APPLICATION, 47 170 370 RAMAN SPECTROSCOPY, 98 242 283 RECALLING, 24 RECIPROCATING SEAL, 23 RECORDING MEDIA, 51 REFRIGERANT, 219 225 REGULATION, 13 76 91 157 242 251 265 293 309 310 REINFORCED HOSE, 79 206 REINFORCED RUBBER, 18 35 81 85 109 139 154 191 235 267 278 329 335 REJECT, 51 REJECT RATE, 83 RELIABILITY, 214 244 305 REPAIR, 39 72 77 189 222 275 314 381 REPLACEMENT, 77 REPLACEMENT TYRE, 13 24 72 308 RESEARCH, 11 96 104 129 131 132 167 208 250 266 280 294 328 RESILIENCE, 22 145 218 251 362 RETREAD, 10 20 40 72 76 85 245 250 280 308 312 314 375 381 RETREADING, 4 16 53 81 91 280 375 381 REVERSE ENGINEERING, 8 REVIEW, 8 9 17 23 43 47 66 71 91 95 104 107 108 120 122 127 129 135 143 155 158 164 168 170 178 185 221 229 242 245 246 267 286 295 300 301 303 304 311 313 315 322 325 330 363 371 377 378 383 RHEOLOGICAL PROPERTIES, 8 15 58 81 82 92 93 111 136 143 144 177 178 188 201 217 252 285 341 ROCKET, 173 ROCKET MOTOR, 6 205 262 ROCKET PROPELLANT, 6 173

© Copyright 2002 Rapra Technology Limited

Subject Index

ROLL COATING, 15 ROLLER, 102 158 373 ROLLING DIAPHRAGM, 18 ROLLING RESISTANCE, 7 14 81 181 245 ROOF, 38 60 232 269 307 323 ROUGHNESS, 84 92 136 158 188 RUBBER TO METAL BONDING, 15 16 59 69 81 RUBBERISED ASPHALT, 269 RUN-FLAT, 85 189 RUPTURE, 3 82 85 133 148 163 171 179 202 205 215 236 256 263 266 321 324 340 341 376

S SAFETY, 7 13 20 32 52 53 78 91 119 131 132 175 189 200 242 286 381 SAFETY FOOTWEAR, 200 SALINITY, 148 SANITARY APPLICATION, 47 320 SCANNING ELECTRON MICROSCOPY, 33 69 128 134 148 153 175 209 218 229 231 264 269 277 322 329 351 379 SCORCH, 81 136 144 146 178 SCUFF RESISTANCE, 200 SEA WATER, 21 203 235 278 357 366 367 SEAL, 1 18 19 23 31 44 45 47 51 54 61 63 66 79 82 89 93 106 124 125 141 160 176 184 196 198 202 203 204 208 212 214 218 219 224 225 226 230 234 237 238 240 251 253 254 260 276 284 287 292 302 347 349 351 353 354 360 362 368 376 SEALANT, 2 45 70 129 199 207 211 222 297 298 299 307 319 320 359 374 382 SEALING, 23 79 284 SEALING RING, 353 SEAM, 200 323 SENSOR, 40 84 85 92 106 127 SERVICE LIFE, 7 14 21 22 41 44 48 56 58 61 62 81 82 85 96 98 110 126 129 148 158 176 180 189 190 193 200 204 218 235 244 245 253 261 280 281 287 289 305 332 338 369 374 375 SERVICE PROPERTIES, 6 166 196 258 272 352 SERVOHYDRAULIC, 182 183 SHAFT SEAL, 176 214 349 380 SHARKSKIN, 92 188 285

SHEAR, 35 92 136 144 158 178 180 182 183 188 190 195 201 213 216 252 267 307 341 366 SHEAR MODULUS, 144 158 160 183 201 SHEAR PROPERTIES, 58 92 158 160 348 SHEAR STRAIN, 46 139 183 190 366 SHEAR STRESS, 58 92 158 190 206 348 SHEET, 82 136 139 200 269 319 SHELF LIFE, 167 192 237 289 SHOCK ABSORBER, 146 169 261 345 SHRINKAGE, 44 178 225 SIDEWALL, 4 57 81 83 85 108 123 127 134 135 177 189 245 344 SIDING, 38 SILICA, 58 99 135 177 181 188 217 364 SILICONE POLYMER, 70 126 174 264 285 SILICONE RUBBER, 23 29 30 67 79 88 112 129 176 182 188 199 207 211 217 218 224 231 256 263 319 320 331 347 SIMULATION, 11 98 177 188 190 207 215 246 247 252 SKID RESISTANCE, 189 SKIM RUBBER, 39 81 SKIN IRRITATION, 164 SLIDING WINDOW, 319 SLIP, 158 171 SLIP RESISTANCE, 200 SLIPPAGE, 165 SLITTING, 25 232 SMOOTHNESS, 84 92 158 188 SNOW TYRE, 189 SOFTENING, 182 203 SOFTENING POINT, 192 SOLAR RADIATION, 207 SOLE, 200 318 SOLUBILITY, 19 21 31 69 111 178 202 203 268 290 SOLVENT, 15 69 133 178 189 204 225 241 268 SOLVENT EXTRACTION, 69 133 382 SOLVENT RESISTANCE, 15 189 261 268 SONAR APPLICATION, 278 SOUR GASOLINE, 204 239 SPACE SHUTTLE, 362 SPARE TYRE, 77 189 SPECIFICATION, 11 42 44 101 181 242 299 371 385

© Copyright 2002 Rapra Technology Limited

SPEED, 11 72 127 157 163 177 SPLITTING, 28 SPORTS SHOE, 318 STABILISER, 37 65 73 75 98 133 195 213 252 279 315 STAINING, 135 213 269 STANDARD, 11 12 13 16 20 22 37 42 44 53 62 94 96 97 101 113 120 129 144 164 167 170 183 200 204 217 224 245 250 295 297 299 303 305 307 313 319 326 363 371 385 STANDARD MALAYSIAN RUBBER, 145 246 STATIC, 191 259 364 STATIC SEAL, 23 44 66 STATISTICS, 9 17 58 67 72 78 86 95 170 210 245 304 STEEL, 69 81 154 157 182 190 233 366 367 369 STEEL BELTED, 24 40 83 85 191 STEEL CORD, 77 81 85 139 191 278 STEEL FIBRE-REINFORCED RUBBER, 81 85 139 191 STEERING GEAR, 225 270 STIFFNESS, 37 61 81 82 139 146 158 163 167 176 180 182 183 190 259 STORAGE, 15 178 189 205 247 252 258 363 386 STORAGE MODULUS, 144 201 STORAGE STABILITY, 167 189 200 STORAGE TANK, 71 STRAIN, 45 46 50 69 82 134 136 139 144 145 152 158 160 176 177 182 183 184 190 191 201 202 204 215 216 218 243 297 340 366 STRAIN CRYSTALLISATION, 69 136 145 STRAIN-HARDENING, 136 191 201 STRAIN RATE, 82 134 136 144 163 191 201 323 STRAIN-SOFTENING, 136 STRENGTH, 60 90 129 141 212 236 246 277 289 324 335 STRESS, 6 15 32 69 82 89 92 94 134 136 144 145 146 148 154 158 176 177 182 183 190 191 201 202 206 215 216 218 243 261 287 288 289 307 315 323 340 347 348 353 364 370 STRESS ANALYSIS, 18 35 183 235 STRESS CONCENTRATION, 82

103

Subject Index

92 134 136 163 176 191 201 294 340 347 STRESS CRACKING, 9 49 74 154 213 STRESS CRAZING, 49 74 STRESS DISTRIBUTION, 82 109 158 201 STRESS RELAXATION, 17 45 54 61 82 134 139 144 145 176 183 201 237 259 287 288 326 340 STRESS SOFTENING, 163 182 STRESS-STRAIN PROPERTIES, 4 17 36 45 46 82 109 134 136 145 153 158 160 161 163 167 182 186 190 191 201 215 216 218 243 259 267 294 344 350 370 STRESSES, 6 15 32 69 82 89 92 94 134 136 144 145 146 148 154 158 STRETCHING, 133 134 201 STRIATION, 154 266 STRIP, 139 176 STRUCTURAL SEALANT, 207 298 299 STYRENE-BUTADIENE RUBBER, 37 50 75 98 99 158 163 171 195 201 213 218 220 224 246 247 252 291 337 339 340 342 376 STYRENE-BUTADIENESTYRENE BLOCK COPOLYMER, 164 STYRENE-ETHYLENE BUTYLENE-STYRENE BLOCK COPOLYMER, 164 STYRENE RUBBER, 67 SUBSTRATE, 15 84 298 322 374 SULFUR, 37 42 69 117 133 135 154 203 204 213 218 306 326 340 SUNLIGHT, 123 207 241 SUPERPOSITION PRINCIPLE, 41 158 SURFACE ANALYSIS, 51 69 135 230 277 SURFACE CRACKING, 24 139 146 188 SURFACE DEFECT, 8 15 51 92 106 SURFACE DEGRADATION, 98 112 135 153 195 215 216 230 269 SURFACE FINISH, 58 92 200 SURFACE PROPERTIES, 84 123 136 153 158 188 197 209 271 274 301 379

104

SURFACE TREATMENT, 15 96 241 298 300 SURGICAL APPLICATION, 86 88 101 138 152 159 166 174 175 194 210 231 258 271 321 331 352 379 SURGICAL GLOVE, 86 101 138 SURGICAL GOWN, 88 SWELLING, 44 54 69 93 133 176 179 203 204 212 218 219 225 226 256 259 268 306 319 340 354 376 382 SWELLING AGENT, 268 382 SYNCHRONOUS BELTING, 103 107 110 172 SYNERGISM, 187 213 326 342

T T-JOINT, 79 TACK, 64 144 177 200 218 TANK, 71 218 220 276 337 339 345 TEAR, 93 267 TEAR ENERGY, 134 182 184 202 290 TEAR RESISTANCE, 37 64 118 TEAR STRENGTH, 37 64 118 145 146 183 202 217 324 372 TEARING, 22 92 109 177 182 184 202 TEMPERATURE RESISTANCE, 238 355 TENSILE MODULUS, 136 144 201 216 256 TENSILE PROPERTIES, 2 17 35 50 58 65 67 82 89 93 111 115 129 133 134 136 144 145 146 153 154 161 163 167 204 216 248 256 258 263 269 288 326 351 372 376 384 TENSILE STRAIN, 35 82 145 191 201 TENSILE STRENGTH, 58 65 67 93 115 129 134 144 145 154 164 183 191 195 201 213 215 216 217 218 219 288 351 372 376 TENSILE STRESS, 35 82 169 191 201 211 225 316 TENSION, 36 46 158 182 190 191 288 307 TEST EQUIPMENT, 10 19 85 133 144 163 177 182 183 201 217 218 TEST METHOD, 5 7 8 11 16 17 18 19 22 37 38 39 42 44 45 46 47

53 55 62 64 67 72 78 93 96 97 112 125 126 129 130 131 176 183 204 215 216 217 TEST SPECIMEN, 98 139 183 216 217 218 224 THERMAL ANALYSIS, 8 21 185 THERMAL CONTRACTION, 82 THERMAL CYCLING, 45 82 251 347 THERMAL DEGRADATION, 6 9 15 17 29 49 62 64 81 90 98 111 130 133 135 144 146 158 168 205 213 215 216 223 266 291 297 307 316 326 355 369 THERMAL EXPANSION, 82 90 251 347 THERMAL HISTORY, 136 THERMAL INSULATION, 276 299 THERMAL PROPERTIES, 69 82 89 136 145 185 202 204 337 339 345 347 THERMAL RESISTANCE, 29 42 THERMAL STABILITY, 2 4 29 81 130 146 176 198 204 219 225 240 247 261 266 312 355 376 THERMOGRAVIMETRIC ANALYSIS, 21 43 143 185 242 378 THERMOOXIDATIVE DEGRADATION, 9 98 133 168 213 227 369 THICKNESS, 3 15 51 64 83 84 94 139 145 158 163 184 202 215 216 232 264 318 367 370 THIN FILM, 145 164 TIME DEPENDENCE, 17 41 45 69 180 201 202 203 204 288 367 TIME TEMPERATURE SUPERPOSITION PRINCIPLE, 41 158 TIMING BELT, 156 TOILET, 218 TOLERANCE, 51 64 83 246 TOOTHED BELTING, 103 107 110 121 156 TORPEDO, 193 TORQUE, 144 190 217 246 247 252 TORSION, 46 137 182 190 TOXICANT, 367 TOXICITY, 132 224 286 293 377 TRACK, 190 220 337 339 372 TRACTION, 147 189 200 TRACTOR, 316 TRACTOR CAB, 79

© Copyright 2002 Rapra Technology Limited

Subject Index

TRACTOR TYRE, 20 TRAILER TYRE, 314 TRANSMISSION ELECTRON MICROSCOPY, 33 128 134 351 TRANSMISSION FLUID, 225 TRANSPARENT, 74 139 188 290 TRANSVERSE CRACKING, 139 TREAD, 4 7 11 13 14 16 20 24 34 37 39 52 81 83 123 177 181 189 252 308 312 337 381 TREEING, 9 TROUBLESHOOTING, 16 22 26 27 28 29 30 43 71 142 185 192 242 255 283 302 328 334 336 359 361 386 TRUCK TYRE, 4 7 10 40 56 76 81 83 85 91 142 151 177 191 280 286 314 TUBELESS TYRE, 81 189 TYRE, 4 5 7 10 11 13 14 16 20 24 32 37 38 39 40 52 53 55 56 57 72 76 77 78 81 83 84 85 87 91 97 105 108 114 123 127 134 135 142 149 150 151 157 162 163 170 177 189 191 244 245 250 252 267 275 280 286 293 294 304 308 312 314 328 330 340 344 355 375 381 TYRE BEAD, 83 294 TYRE BELT, 5 39 81 83 177 191 TYRE CARCASS, 81 177 TYRE CASING, 81 85 TYRE CORD, 35 57 81 83 85 162 177 191 267 344 TYRE DEFLATION, 189 TYRE FITTING, 375 TYRE INFLATION, 56 81 85 189 191 275 375 TYRE INNER LINER, 5 81 177 TYRE NOISE, 7 189 TYRE PRESSURE, 5 32 81 85 189 191 375 TYRE REPAIR, 189 TYRE SHOULDER, 24 39 245 TYRE SIDEWALL, 40 55 TYRE TREAD, 4 7 16 24 34 52 123 250 308 312 337 381 TYRE VALVE, 56

U ULTRASONIC TEST, 85 183 UNDER INFLATION, 85 91 105 UNDER-THE-BONNET APPLICATION, 19 79 80 130 146

UNDERGROUND PIPE, 38 UNDERWATER APPLICATION, 357 UNVULCANISED, 98 144 177 247 252 UV DEGRADATION, 71 98 168 189 241 326 UV IRRADIATION, 17 37 58 112 187 UV RESISTANCE, 195

V V-BELT, 107 147 316 VALVE, 47 51 56 113 198 208 218 251 260 VALVE SEAT, 93 VALVE STEM SEAL, 51 VAPOUR PERMEABILITY, 81 VAPOUR PRESSURE, 178 VARIABILITY, 183 217 VASCULAR PROSTHESIS, 159 VEHICLE, 20 155 330 VEHICLE ROOF, 222 VEHICLE SHELL, 335 VEHICLE SUSPENSION, 23 137 VEHICLE TRANSMISSION, 370 VIBRATION, 182 183 348 VIBRATION DAMPER, 146 186 215 216 345 VIBRATION DAMPING, 79 296 VIBRATION INSULATION, 49 VIBRATION PAD, 345 VIBRATIONAL SPECTROSCOPY, 69 98 143 145 VIDEO ANALYSIS, 69 177 188 VIDEO CAMERA, 51 VIRUS, 116 131 VISCOELASTIC PROPERTIES, 4 45 92 136 144 158 183 188 201 252 340 VISCOSITY, 8 15 58 81 92 93 136 144 177 178 188 201 217 226 246 252 257 VOICE PROSTHESIS, 231 VOID, 25 36 163 178 278 285 VOLATILITY, 1 15 111 133 178 260 275 291 326 337 VOLUME CHANGE, 93 117 201 268 VULCANISATE, 15 37 64 69 89 90 98 144 154 162 169 177 183 188 201 218 224 236 241 247 252 268 272 287 288 289 306 316 325 329 347 351 354 366

© Copyright 2002 Rapra Technology Limited

VULCANISATION, 15 26 37 42 69 81 82 90 93 133 134 135 144 145 146 154 164 169 176 177 178 188 200 213 216 217 218 224 252 291 340 353

W WALL THICKNESS, 167 190 WARP, 18 WASHER, 93 218 WASHING, 112 326 WATER ABSORPTION, 200 224 256 259 261 278 307 320 353 364 366 382 WATER ADSORPTION, 93 218 WATER EXTRACTION, 98 224 WATER PERMEABILITY, 22 101 WATER PIPE, 79 96 351 WATER RESISTANCE, 2 200 203 224 261 278 307 320 353 382 WATER SYSTEM, 93 218 WATER TREATMENT, 93 117 354 WATER VAPOUR PERMEABILITY, 81 256 WATERPROOF, 200 320 WAX, 15 55 58 75 123 213 257 WEAR, 14 18 41 81 113 147 157 176 189 214 220 308 330 339 349 375 380 WEAR RESISTANCE, 55 72 99 158 171 176 200 372 WEATHER RESISTANCE, 17 75 81 95 123 129 WEATHER STRIPPING, 58 WEATHERING, 17 75 81 95 123 168 189 195 207 213 235 241 289 297 326 WEATHERING RESISTANCE, 37 63 75 81 95 129 WEATHEROMETER, 326 WELD STRENGTH, 246 WHEEL, 189 275 WHEEL RIM, 286 WICKING, 278 WIND RESISTANCE, 60 WINDOW SEALANT, 319 WINTER TYRE, 189 245 WRINKLE, 92

X X-RAY ANALYSIS, 69 83 205 269 277 301 322

105

Subject Index

Y YEAST, 231 YELLOWING, 111 326 327 YIELD, 201 YOUNG’S MODULUS, 79 158 163 167 176 183 188 192 202 211 218 225 316 348

Z ZINC OXIDE, 37 42 98 224 326 340 ZIPPER FAILURE MODE, 40 ZIPPER MECHANISM, 85

106

© Copyright 2002 Rapra Technology Limited

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