Ageing of Rubber - Accelerated Weathering and Ozone Test Results

O3 Ageing of Rubber Accelerated Weathering and Ozone Test Results R.P. Brown, T. Butler and S.W. Hawley Europe’s lea...

Author: R. | P. Brown | T. Butler | S. | W. Hawley

92 downloads 1293 Views 1MB Size Report

This content was uploaded by our users and we assume good faith they have the permission to share this book. If you own the copyright to this book and it is wrongfully on our website, we offer a simple DMCA procedure to remove your content from our site. Start by pressing the button below!
Report copyright / DMCA form

DOWNLOAD PDF

O3

Ageing of Rubber

Accelerated Weathering and Ozone Test Results

R.P. Brown, T. Butler and S.W. Hawley

Europe’s leading independent plastics and rubber specialists

Ageing of Rubber Accelerated Weathering and Ozone Test Results

R.P. Brown, T. Butler and S.W. Hawley Rapra Technology Limited

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 Shawbury, Shrewsbury, Shropshire SY4 NNR, United Kingdom Telephone: +44 (0)1939 250383 Fax: +44 (0)1939 251118 http://www.rapra.net

Practical Guide to Polyethylene

First Published in 2001 by

Rapra Technology Limited Shawbury, Shrewsbury, Shropshire, SY4 4NR, UK

©Copyright 2001 Rapra Technology Limited

A catalogue record for this book is available from the British Library. ISBN: 978-1-85957-264-1 Every effort has been made to contact copyright holders of any material reproduced within the text and the authors and publishers apologise if any have been overlooked.

All rights reserved. Except as permitted under current legislation no part of this publication may be photocopied, reproduced or distributed in any form or by any means or stored in a database or retrieval system, without the prior permission from the copyright holder. The report is published in good faith, but 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 herein

Typeset by Rapra Technology Limited Printed and bound by Lightning Source UK Ltd

2

Contents 1. Introduction ...................................................................................................................... 1 2. Materials .......................................................................................................................... 1 2.1 Original Materials ..................................................................................................... 1 2.2 New Materials ........................................................................................................... 2 3. Preparation of Test Pieces ................................................................................................. 3 4. Physical Tests .................................................................................................................... 3 5. Exposure of Test Pieces ..................................................................................................... 3 5.1 Weathering ................................................................................................................. 3 5.2 Ozone Exposure......................................................................................................... 4 6. Weathering Results (Appendix 2) ..................................................................................... 4 6.1 Presentation ............................................................................................................... 4 6.2 Uncertainty ................................................................................................................ 5 6.3 Interpretation of results ............................................................................................. 5 7. Ozone Results (Appendix 3) ............................................................................................. 6 8. Discussion ......................................................................................................................... 6 8.1 Weathering ................................................................................................................. 6 8.1.1 General ............................................................................................................. 6 8.1.2 Hardness .......................................................................................................... 7 8.1.3 Modulus ........................................................................................................... 8 8.1.4 Tensile Strength ................................................................................................ 8 8.1.5 Elongation at Break .......................................................................................... 9 8.1.6 Effect of Temperature ....................................................................................... 9 8.2 Ozone ...................................................................................................................... 11 9. Conclusions .................................................................................................................... 12 References ........................................................................................................................... 12 Appendix 1 - Compound Details ......................................................................................... 13 Appendix 2 - Weathering Results ........................................................................................ 25 Compound A - Natural Rubber - Standard .................................................................... 27 Compound B - Natural Rubber - Good Ageing .............................................................. 31 Compound C - Natural Rubber - Mineral Filler Loaded ................................................ 35 Compound D - Natural Rubber - Mineral Filler (Heavy Loaded) .................................. 39

© Copyright 2001 Rapra Technology Limited

i

Compound E - Styrene Butadiene Rubber - General Purpose ......................................... 43 Compound F - Styrene Butadiene Rubber - Good Ageing ............................................... 47 Compound G - Styrene Butadiene Rubber - General Purpose ......................................... 51 Compound H - Styrene Butadiene Rubber - Good Ageing .............................................. 55 Compound J - Butyl Rubber - General Purpose .............................................................. 59 Compound K - Butyl Rubber - Good Ageing .................................................................. 63 Compound L - Polychloroprene - General Purpose ........................................................ 67 Compound M - Polychloroprene - Natural Ageing ......................................................... 71 Compound N - Polychloroprene - Heat Ageing .............................................................. 75 Compound P - Nitrile Rubber - General Purpose ........................................................... 79 Compound R - Polychloroprene - Good Ageing ............................................................. 83 Compound S - Miscellaneous - Acrylate Rubber ............................................................ 87 Compound T - Miscellaneous - Chlorosulphonated Polyethylene .................................. 91 Compound W - Miscellaneous - Polysulphide Rubber .................................................... 95 Compound X - Miscellaneous - Silicone Rubber ............................................................ 99 New Compounds Compound N1 - FVMQ ............................................................................................... 103 Compound N2 - HNBR ............................................................................................... 107 Compound N3 - Epoxidised Natural ............................................................................ 111 Compound N4 - Chlorinated Polyethylene ................................................................... 115 Compound N5 - Fluorocarbon ..................................................................................... 119 Compound N6 - Exxpro ............................................................................................... 123 Compound N7 - Epichlorohydrin ................................................................................. 127 Compound N8 - EPDM ................................................................................................ 131 Compound N9 - EVA ................................................................................................... 135 Compound N10 - PU .................................................................................................... 139 Participant’s Compounds Compound P1 ............................................................................................................... 143 Compound P3 ............................................................................................................... 147 Compound P4 ............................................................................................................... 151 Compound P5 ............................................................................................................... 155 Compound P6 ............................................................................................................... 159 Compound P7 ............................................................................................................... 163 Compound P8 ............................................................................................................... 167 Compound P9 ............................................................................................................... 171 Compound P10 ............................................................................................................. 175 Appendix 3 - Ozone Results .............................................................................................. 181

ii

Ageing of Rubber - Accelerated Weathering and Ozone Test Results

1 INTRODUCTION A long-term natural ageing programme was started in 1958 when 19 rubber compounds were exposed at 3 locations. The final sets of test pieces were withdrawn in 1998 giving a total of 40 years of natural ageing. The results of the physical tests carried out at intervals over the 40 years have been published [1]. The 19 compounds were re-mixed in 1999–2000 in order that accelerated ageing tests could be carried out for direct comparison with the results from natural ageing. A total of 20 new compounds were also mixed to represent polymers not available in 1958 and to reflect changes in compounding practice. Ten of these materials were formulations directly nominated by industry covering materials of current interest to particular companies. The 39 materials were subjected to accelerated heat ageing for a series of times and temperatures, artificial weathering and exposure to ozone. This report details the results of the artificial weathering and ozone exposure tests and makes comparisons with the results after natural ageing. The accelerated heat ageing results will be published separately (Ageing of Rubber— Accelerated Heat Ageing Results).

2 MATERIALS The test pieces used in the programme were produced from compounds with the formulations given in Appendix 1. For reasons of confidentiality, the materials nominated by industry are only described by polymer type. As regards the original 19 materials, it is perhaps surprising that compounding has changed relatively little and most of the formulations are relevant today. The new compounds formulated by Rapra, with advice from the project Industry Steering Group, were selected as being the more commercially important of the many polymers and compounding ingredients introduced since the start of the project in 1958.

2.1 Original Materials Four natural rubber compounds were selected. Compound A was selected as it had been used at Rapra for many years as a standard material which loosely represented a tyre tread or high grade conveyor belt cover. Compound B has what became known as an efficient vulcanising system with no elemental sulphur, although the term had not then been coined. Compound C represents a fairly high rubber content, non-black filled material. The final natural rubber compound D was requested by the electrical side of the industry as a highly loaded, low grade insulation material and was said to exhibit good ageing properties in the dark. Compounds E and F are styrene butadiene rubbers (SBR) corresponding to A and B whilst G and H are oil extended versions. Compounds J and K were referred to as general purpose and good ageing butyl compounds, respectively. They represent the extremes of polymer available, with high and low unsaturation, respectively.


1

The three polychoroprene compounds came from the polymer supplier and were labelled general purpose (L), natural ageing (M) and heat ageing (N). The two nitrile compounds were suggested by the main UK supplier at the time to represent a general purpose material (P) and a good ageing formulation (R). The remaining compounds were also suggested by the relevant suppliers as general purpose materials.

2.2 New Materials Compound N1 is a fluorosilicone-based on LS 2380U. The hydrogenated nitrile compound N2 is a formulation to give heat resistance. Compound N3 is an epoxidised natural rubber with low black loading used in an acoustic application. The chlorinated polyethylene, compound N4, represents a formulation for hose tube and cover material. Compound N5 is a 70 IRHD fluorocarbon-based material for seal applications. Compound N6 is an Exxpro material (isobutylene p-methylstyrene copolymer) described as general purpose. The epichlorohydrin material, compound N7, is also formulated for general purpose use. The sulphur cured ethylene propylene terpolymer (EPDM), compound N8, is a formulation typically used for radiator hose applications. Compound N9 is an ethylene vinyl acetate cable sheathing material. Compound N10 is a general purpose millable polyurethane. Compounds P1–P10 are materials submitted by industry participants: Compound P1

ethylene propylene copolymer

Compound P2

siloxane material

Compound P3

medium nitrile, carbon black filled with EV sulphur cure

Compound P4

nitrile, NF standard 0115/2

Compound P5

EPDM, NF standard 0115/1

Compound P6

Vamac G material, black filled with a Diak/DOTG cure system

Compound P7

W type polychloroprene with small amount of SBR, carbon black filled, sulphur/metal oxide cure

Compound P8

natural rubber

Compound P9

thermoplastic rubber—Santoprene 101 55 V185 from AES

Compound P10

nitrile

Compound P2 was not tested for weathering and ozone resistance because it was a special purpose cellular material.

2


3 PREPARATION OF TEST PIECES Batches of all 39 compounds were mixed. In most cases 2 batches were needed, which were blended. Standard 2 mm sheets were produced by compression moulding. The cure times used in 1958 for the original materials could not be derived from measurements in a curemeter as these instruments were only in the experimental stage. Hence, they were derived from a programme of curing for various times and measuring physical properties. The cure times for the new materials were derived from measurements on a Monsanto rheometer. The cure conditions arrived at are given in Appendix 1.

4 PHYSICAL TESTS Ideally, the same physical tests as used in the natural ageing programme would have been used to monitor changes but the volume of work that would have entailed was prohibitive. Hence, the following properties were selected for monitoring the artificial weathering exposures: • tensile strength, • elongation at break, • stress at 100% elongation, • stress at 300% elongation, and • hardness. These properties correspond to properties monitored in the natural ageing programme. It may be noted that for the heat ageing exposures, compression set and dynamic properties were also measured. Monitoring of the effects of ozone exposure was by observation of cracks using a x7 lens. Tests were carried out in general accordance with the current ISO methods [2–3]. For tensile properties, type 2 dumbbells were used, with 3 dumbbells being tested at each measurement point. Hardness measurements were made by taking 5 readings on one test piece. Ozone exposure test pieces were in the form of T50 dumbbells.

5 EXPOSURE OF TEST PIECES 5.1 Weathering Test pieces were exposed in QUV fluorescent tube apparatus using UVA 340A lamps with a black panel temperature of 45 °C and a cycle of 4 hours condensation and 4 hours dry (3 cycles per day) [4]. By agreement with the supplier of material P2, it was not tested for weathering resistance.


3

Seven sets of 3 dumbbells and a piece of sheet for hardness measurements were exposed. Sets of test pieces were removed and tested at approximately 30 day intervals up to 6 months (leaving 1 set spare). Test pieces were conditioned for a minimum of 16 hours at 23 °C and 50% relative humidity prior to test.

5.2 Ozone Exposure Test pieces were strained to 5, 10, 15, 20 and 30%. After conditioning for 72 hours, they were exposed to ozone at 23 °C [5]. All materials were exposed to 50 pphm of ozone for up to 1 month. The exposure was repeated at 200 pphm of ozone but excluding those materials that had cracked to grade 3 most rapidly at 50 pphm (E, F, G, H, N3 and P3). By agreement with the supplier of material P2, it was not tested for ozone resistance. The test pieces were examined after nominally 2, 4, 8, 16 and 24 hours and daily thereafter and any cracking noted.

6 WEATHERING RESULTS (APPENDIX 2) 6.1 Presentation The results for each property after artificial weathering were plotted as a function of exposure time. The tensile properties are the mean of results on 3 test pieces and the hardness result is the median of 5 readings. A best fit line was then constructed by computer for each graph using proprietary software which selects from hundreds of functions. Hence, the function in each case was selected on an empirical basis and there is no a priori reason to suppose that the same function would be valid for extrapolations. Alternative functions might be considered preferable. The initial and 6 month values for each property were then read off the best fit lines. This means that these values are not necessarily the same as the initial and final plotted data points. This treatment gives no special weighting to the initial unaged data, nor to the final 6 month results. From the initial and final values, the differences and the differences expressed as percentage change have been tabulated. Values were generally read to three significant figures and, to avoid misleading rounding errors, the percentage changes are given to two significant figures. This does not imply accuracy to the number of figures recorded. Whenever possible, values are quoted for both 100% and 300% modulus. In some cases, values for 300% were not available for the longer exposure times. This necessitated the extrapolation of the best fit line through the 6 month point in order to produce a comparative percentage change value.

4


6.2 Uncertainty In order to make a realistic assessment of the significance of the results, it is necessary to make an estimation of the variability of the test results. An indication of variability is illustrated on the graphs by means of error bars. These were derived from standard deviations for repeatability taken mostly from precision statements in ASTM and ISO test method standards. The repeatability standard deviations were multiplied by 2 to give the 95% confidence intervals. It will be appreciated that these error bars simply give an idea of the degree of scatter which might generally be expected. Comment is made below on the uncertainty of estimates made by extrapolation of the results but no attempts at quantification have been made.

6.3 Interpretation of results A quick snapshot view of the changes which have taken place over 6 months exposure is given by Table 1 for each material. However, the figures giving change and percentage change need to be viewed in context with the level of the property measured and the uncertainty. For example, the 100% modulus figures are generally small so that a relatively minor change may appear as a large percentage change and the experimental uncertainty is large. The graphical presentation allows at least a subjective assessment to be made of the significance of the recorded changes. In most cases, a clear trend is apparent with little masking by scatter of results. It is appreciated that, in general, the change of property with time is not linear and, hence, it is not strictly correct to make predictions based on the change over 6 months. Using this simplified approach is justified on the grounds that: • the prime object of the artificial weathering trials was to obtain the order of magnitude of the effects of weathering in comparison to those from heat ageing, and • the uncertainties of subtracting the effect of heat alone and extrapolating to ambient weathering conditions are in any case very large. Estimates of the expected changes in properties over 6 months from exposure to a temperature of 45 °C were obtained by making Williams Landel Ferry (WLF) transforms of the accelerated ageing results reported separately. By subtraction of these figures from the weathering results, the effect due to light (and possibly moisture) over 6 months can be estimated. These effects are tabulated in Table 2 for each material. Missing figures are due to the raw data being insufficient or very highly variable. If an acceleration factor due to the higher irradiance in the weathering apparatus compared to natural sunlight is assumed, it is possible to estimate the effects of weathering at 23 °C under natural exposure to light. It is appreciated that such acceleration factors are generally regarded as invalid because of the variation in solar radiation and the differences in distributions of the wavelengths of the light. However, to give an estimate of the order of magnitude of change that might be expected from weathering, acceleration factors were derived from quoted irradiance


5

and annual solar radiation figures. The factors derived for the UVA 340 lamps were Arizona 6.0, Florida 7.1 and London 14.0. Estimates for 10 years’ exposure in London are given in the same table, calculated from: C⋅

10 1 ⋅ 0.5 14

where C is the net change due to weathering after 6 months. The 10-year period is equivalent to only a relatively modest extrapolation of the 6 month exposure graphs but, because of the uncertainty in the acceleration factor, the figures can at best be considered as tentative.

7 OZONE RESULTS (APPENDIX 3) The times to first observed cracking (Grade 1 cracking) as a function of strain are given for results at 50 pphm and at 200 pphm, along with the times to reach Grade 3 cracking (Tables 1– 4). Compounds which did not crack have been omitted. Graphical representations of the times to first cracking are given in Figures 1 and 3 and of times to Grade 3 cracking in Figures 2 and 4. The times to first observed cracking were plotted as a function of strain and an exponential function fitted. Selected graphs are given in Figures 5–7. It is not sensible to attempt to interpret accelerated ozone exposure tests in terms of times to cracking under ambient conditions. Clearly, the best result is for there to be no cracking, and compounds which have not cracked after 1 month at 200 pphm can be considered totally resistant. Distinction between materials that have cracked can be made on the basis of the length of time to cracking at a given ozone concentration, the maximum strain without cracking and the severity of cracking. As an indication of performance in relation to service, a material passing a typical specification requiring no cracking after 7 days at 50 pphm and 20% strain would be expected to give at least 5 years’ service without cracks under typical ambient conditions.

8 DISCUSSION 8.1 Weathering 8.1.1 General Comment is made for each property on the trends seen during accelerated weathering, rather than attempting a detailed analysis of each compound property by property.

6


For the original 19 compounds, the trends are compared to the natural ageing results, always bearing in mind that they were in the absence of light. Then the estimated contributions due to temperature (obtained from accelerated heat ageing tests) and UV light are discussed, and comment made on the magnitude of the estimated net change due to weathering. Several overall observations can be made. Weathering and shelf or heat ageing differ because of the presence of UV light in the former, and it is perhaps not surprising that there are many observed differences in behaviour between the two. However, the direction of change is generally similar with only relatively few cases where there is total conflict. The traditional view has been that weathering, UV light in particular, has minor effect on rubbers. These results show that in many cases accelerated weathering produces quite large changes in properties. Adjusting the results for the effect of temperature often made a big difference to individual properties but overall the effects due to weathering were still found to be very significant. There are considerable differences in the magnitude of the response to weathering as measured by different properties, which illustrates the generally held view that preferably several relevant properties should be investigated in any exposure trial. The ranking of materials is not consistent across different properties which reinforces the need to consider more than one property when characterising or selecting materials. The natural rubber compounds C and D showed significant surface cracking (Appendix 2, Figures 1 and 2), which is illustrated in Figures 1 and 2. The pattern of cracks is reminiscent of ‘alligatoring’ which has been observed on polymeric roof membranes used in hot climates with high UV exposure and intermittent rainfall. This has been attributed to localised stresses due to wetting and drying coupled with degradation due to temperature and UV light. It is perhaps significant that these two compounds (especially D) have high loadings of calcium carbonate.

8.1.2 Hardness For all materials, there was either an increase in hardness or the hardness was very little changed over the six months. For the majority of compounds, the increase was less than 10% and for 15 compounds below 5%. Compounds D, N, T, W, P7 and P8 had increases above 10% with natural rubber D and Hypalon T above 20%. In many cases, there is a tendency for the rise in hardness to be more rapid at the beginning and then to plateau out. This is significant for compounds D, E, F, M, N, T, W, N10 and P10 with the effect being very large in the case of natural rubber D and Hypalon T. These were the two materials that showed the greatest total rise. One important implication of this is that linear extrapolation would be very misleading. It would be reasonable to suppose that the rapid increase was largely a surface effect.


7

Compounds N2, N4, N9, P1 and P4 apparently exhibit slightly more complex behaviour with P1 and P4 possibly reducing in hardness towards the end of the 6 months (P1 also showing a minimum) and N2, N4, and N9 possibly increasing towards the end of the 6 months. These changes are, however, relatively small. Compounds N5 and N6 show a tendency for the rate of hardness increase to rise over the exposure period. The natural ageing behaviour was similar in that all materials either increased in hardness or were very little changed. A plateau effect was seen in natural ageing for compounds E, F, G, H, K, P and R, and hence does not correspond exactly with the plateaux in weathering.

8.1.3 Modulus For the modulus at 100%, there were no cases of a really sharp initial rise, although the curve fitting for compounds D, E and N10 show a small step. For most materials, there was either a rise in modulus or little change. However, in a number of cases there was a tendency for a modest decrease, notably compounds C, D, H, S, X, P5, N1, N5 and P9. Compound N6 showed a large initial drop in modulus and then a plateau. Also, in several cases there was some evidence for a maximum in the modulus–time curve. Most changes in modulus were fairly low with only compounds E, G, T, W and N10 having rises of over 20% and A, N, and P8 of over 40%. The drop in modulus for N6 was over 20%. The 100% modulus results are not entirely consistent with hardness in that there were some decreases and there is not good correlation for materials showing the greatest changes. There were no cases of 300% modulus showing a significant sharp initial rise. Only P1 and P10 had an appreciable tendency to have a maximum. Generally, the results were reasonably consistent with the 100% figures but at 300% A, M, and P8 had rather less modulus increase, and N had much lower increase. C and P1 showed a larger decrease, L no decrease and P, R and N3 a larger increase. The Hypalon T was completely inconsistent with 100% modulus increasing but 300% modulus decreased. The nitrile P10 was apparently inconsistent but at both levels it exhibited the same shaped curve with a maximum. It can be argued that good correlation between hardness and modulus would not be expected because of the effect of UV being confined to the surface. This would also affect correlation with the natural ageing.

8.1.4 Tensile Strength The great majority of materials show a decrease or are little changed in tensile strength over the 6 months. However, compounds S, N9, P5 and P6 show a tendency for tensile strength to increase. Compounds N1, N3, N10, P1, P7, P9 and P10 apparently exhibit slightly more complex behaviour. N1, N10 and P1 have a maximum in tensile strength whereas P7, P9 and P10 possibly have an inflexion and N3 a minimum. There is strong indication of a plateau effect in several of the materials, notably compounds B, C, D, F, G, L, R, and T which means that linear extrapolation would be misleading, as it could be for those with more complex behaviour.

8


For more than half the compounds the change in tensile strength is appreciable, with A, B, C, D, F, W, N, R, T, N10, P7, P8, P9 and P10 having over 20% decrease. The natural rubbers C and D and the nitrile P10 suffer very large decreases. There is significant rise in strength for EPDM P5. There are clearly some anomalies in comparison with the natural results, notably the reverse behaviour of the polysulphide W. A plateau effect was not seen in natural ageing.

8.1.5 Elongation at Break The great majority of materials show a decline in elongation at break or change little over the 6 months. Compounds S, X, N5, N6 and P1 possibly increase. Compounds J, N1, N4, N8, N9, P5 and P6 can be said to change relatively little. Also, the majority apparently decline to a plateau level. Compounds K and N5 appear to have a cyclic pattern but this could easily be an effect of variability. P8 follows the typical decrease but there is indication of a plateau being reached. The scatter for N2 is unusually large and it is difficult to see a definite trend. As for tensile strength, over half the materials exhibit considerable change although the elongation at break performance is perhaps not quite as bad. Compounds A, B, D, E, G, N, R, T, N7 and P8 decline by more than 20% with Hypalon T the worst. As a general rule, the tensile strength and elongation changes are not dissimilar. The only real exceptions are for compounds C, N7 and P1. C has a very much greater drop in strength than elongation, N7 a large drop in elongation but no change in strength, whilst for P1 the changes are significantly in opposite directions. Generally, the changes are not in conflict with the natural ageing results, but the latter did not show a plateau effect.

8.1.6 Effect of Temperature The estimates of change due to temperature over 6 months at 45 °C obtained by extrapolation from accelerated ageing (Appendix 2, Table 2) are subject to large uncertainty and may not even be valid. Taking them at face value (accelerated ageing results will be analysed in more detail in a subsequent report), the changes seen on weathering are very similar to the changes predicted for temperature effects in about 37% of the cases (each compound and property equals 1 case). In about 22% of the cases, the change predicted for temperature is significantly smaller or very much smaller than the changes seen in weathering, whilst in about 27%, the change predicted for temperature is significantly larger or very much larger than changes seen in weathering. In about 22% of the cases, there is complete disagreement in that the changes after weathering and predicted for temperature are in opposite directions. Very simplistically, this could be taken to indicate that in about 37% of the cases temperature accounts for all of the changes seen after weathering, that in 22% there is a significant weathering effect in addition to a temperature effect, but that in approaching 50% of the cases the temperature and weathering effects are different. It is highly unlikely that this is totally correct but it does indicate that in the majority of cases there is evidence of a significant effect due to UV and or moisture.


9

When the estimates of net change due to weathering are taken and converted to change after 10 years under UK radiation conditions, the prediction is that in about 65% of the cases the weathering change would be significant (greater than 10%). Whilst again repeating that these predictions are somewhat speculative, there appears to be sufficient evidence to suggest that the effect of weathering alone should not be ignored and may be quite large for some materials. It is interesting to note differences between properties in respect of the weathering changes predicted. The modulus predictions show the most instances of significant weathering change (~83%) and the hardness least (~26%). Tensile strength and elongation show about 62% and 76%, respectively. Modulus results are probably the least reliable because of the uncertainty arising from the relatively low levels of force being measured but no explanation is offered as to why hardness shows the least change. Natural rubber compounds C and D exhibited very obvious surface cracking after the weathering exposure which was not seen in heat ageing tests. Hence, it is logical to conclude that there is firm evidence of a UV (and/or water) effect in these cases. The net weathering predictions for all properties of these materials is 10% or greater. The same is true for natural P8 and epoxidised natural rubber N3 other than hardness. Because of the uncertainties, it would be unwise to be very specific as to which materials are particularly prone to UV degradation. However, the predictions do show significant apparent dependence on formulation, for example, the polychloroprenes L, M and N, and very few materials were little affected for all properties. Elongation at break was reduced by heat ageing for almost all compounds, and in the remaining cases the change was small. For acrylate S, silicone X, fluorocarbon N5, Exxpro N6 and EPDMs P1 and P5, elongation at break increased on weathering. For hydrogenated nitrile N2, chlorinated PE N4 and Vamac P6, change in elongation at break after weathering and heat ageing were in opposite directions. This would imply different reactions for these materials in the two types of exposure. In some cases at least, the weathering effect might involve moisture. The changes in opposing directions are added to obtain the net weathering predictions and, hence, make these figures much larger than the individual results for weathering or heat ageing. The same additive effect applies to the other properties when changes are in opposite directions. This is significant in raising the net weathering predictions for hardness in the cases of fluorocarbon N5 and polyurethane N10, and for tensile strength in the cases of nitrile P, acrylate S and Hypalon T. Also, when the change from weathering is smaller than the change from heat ageing (in the same direction) it results in the predicted net effect being in the opposite direction to the total weathering change, and in some cases larger numerically than the total weathering change. If one was sceptical of predictions from accelerated heat ageing results and argued that the changes during weathering exposure had little contribution from temperature effects, it is interesting to see that there would then be approximately 61% of cases with a predicted weathering change of greater than 10% after 10 years in the UK. This is fractionally smaller than the figure after the temperature effect adjustment had been made and one would again conclude that it would be wise not to ignore weathering effects.

10


8.2 Ozone At 50 pphm (Appendix 3, Tables 1 and 2), compounds L, M, N, N1, N2, N4, N5, N6, N8, N9, N10, P1, P5, P6, P7, P9, S, T and X showed no cracking after 28 days. Compounds J and N7 had only Grade 1 cracks at the highest strains after 24 days. Compound P8 only cracked at the highest strain but rapidly developed Grade 3 cracks at 11 days and broke after 15 days. At 200 pphm (Appendix 3, Tables 3 and 4), compounds N1, N2, N4, N5, N6, N7, N8, N9, N10, P1, P5, P6, P7, P9 S, T and X showed no cracking after 28 days. Compound J had only Grade 1 cracks at the higher strains. It is a little curious that compound N7 showed cracking only at the highest strain at 50 pphm and that compound P8, although again very rapidly developing larger cracks, did not break. Hence, only compounds N1, N2, N4, N5, N6, N8, N9, N10, P1, P5, P6, P7, P9 S, T and X can be said to be completely ozone resistant. N7 is very close to being totally resistant and J and K perform extremely well. The results were generally not surprising. All the natural rubber and SBR compounds cracked relatively quickly, although the natural rubber compound P8 was notable for the improvement that is possible through compounding. The butyl rubbers J and K did crack but only at higher strains and longer times. All the polychloroprene compounds were clear at 50 pphm but the older compounds cracked at 200 pphm. The nitriles, except for the hydrogenated material N2, all cracked at 50 pphm, as did the polysulphide W. The epichlorohydrin N7 barely cracked at 50 pphm and was clear at 200 pphm. The remaining polymers appear to be totally resistant. The performance of polymers with relatively poor ozone resistance is very dependent on the formulation and, in particular, whether an effective antiozonant has been included. This is well illustrated by the difference between compounds A–D and compound P8. It should be noted that for many of the materials in this programme, ozone resistance was not a prime consideration and in consequence they were not well protected. The ranking in terms of the times to first cracking is conveniently seen in Figures 1 and 3 in Appendix 3. At 50 pphm compounds A, C, D, E, F, G, H, P, N3 and P3 had cracked at all strains in under 1 week. Similarly, the ranking in terms of times to grade 3 cracking is shown in Figures 2 and 4. The comparison of the two pairs of diagrams also shows the effect of increasing ozone concentration. In the context of this programme, the most important point to note from these ozone results is that cracking could be a rather more critical factor for the less resistant materials than, for example, heat ageing, if they were used in applications and under conditions conducive to ozone attack. It should also be noted that very little evidence of ozone attack was seen on the samples naturally aged for 40 years. With the exception of compression set, test pieces were not strained and in the shelf ageing conditions used, ambient ozone levels were probably very low. Hence, in contrast to the statement in the previous paragraph, in suitable conditions ozone will not be an important consideration. In thick articles, cracking confined to the surface has no more than cosmetic significance.


11

If cracking does occur its severity, or the rate at which it progresses, is of interest. A very simple measure of the rate of crack growth can be deduced by comparing Figure 1 with Figure 2, and Figure 3 with Figure 4 (in Appendix 3). As an example, there is a clear difference between the natural rubber compounds A–D and the SBR compounds E–H. They all reach first cracking quickly but the SBRs reach grade 3 much more quickly than the natural rubbers. It is also interesting to note the pattern of cracking with strain level for non-resistant compounds. In some cases, a plot of time to cracking against strain appears to show a threshold strain below which cracking does not occur even at long times. A fairly good example is material P4 (Appendix 3, Figure 5). However, in the majority of cases in this work the possibility of a threshold strain is less clear. In the case of material W (Appendix 3, Figure 6), the exposures would need to be continued for longer times and for the least resistant materials tests at strains below 5% would be needed. Where there was some evidence for a threshold strain, it was generally about 5% or even lower which might be difficult to avoid in many applications. Occasionally, such as for material P10 (Appendix 3, Figure 7), it was significantly higher and this could be worth investigating more carefully.

9 CONCLUSIONS An accelerated weathering and ozone exposure programme involving a total of 38 rubber compounds has been successfully completed. The weathering results indicate that the effect of UV light may be significant for many rubbers and in some cases quite large, despite the presence of carbon black. Hence, it would be wise not to ignore the effect of weathering when estimating service life. The well-known fact that polymers vary greatly in their ozone resistance has again been demonstrated. Where non-resistant materials are involved, the likelihood of ozone attack being a problem in service should be carefully considered before undertaking long-term evaluation of thermal ageing performance.

REFERENCES 1.

R.P. Brown and T. Butler, Natural Ageing of Rubber—Changes in Physical Properties over 40 Years, Rapra Technology Limited, 2000.

2.

ISO 37 1994 Rubber, vulcanised or thermoplastic—Determination of tensile stressstrain properties.

3.

ISO 48 1994 Rubber, vulcanised or thermoplastic—Determination of hardness (Hardness between 10 IRHD and 1000 IRHD).

4.

ISO 4665 1998 Rubber, vulcanised—Resistance to weathering.

5.

ISO 1431-1 1989 Rubber, vulcanised or thermoplastic—Resistance to ozone cracking – Static strain test.

12


APPENDIX 1 COMPOUND DETAILS


13

Appendix 1

14


Natural Rubber

Natural Rubber Ingredient

Amount (pphr)

Compound A – Standard

Smoked sheet

100

Curing conditions: 35' @ 141 °C

HAF black

50

Stearic acid

2.5

Pine tar

4.5

Zinc oxide

5

CBS

0.5

PBN

1.0

Sulphur

2.5

Compound B - Good Ageing

Smoked sheet

100


HAF black

50

Stearic acid

0.5

Pine tar

4.5

Zinc oxide

5

TMTD

2.5

PBN

1.0

MBT

1.0

Compound C - Mineral Filler Loaded

Smoked sheet

100


Stearic acid

1.5

Petroleum-based softener

5

Zinc oxide

5

CBS

0.5

PBN

1.0

Sulphur

2.5

Precipitated calcium carbonate

80

Compound D - Mineral Filler

Smoked sheet

100

(Heavy Loaded)

Stearic acid

1.5



25

Zinc oxide

5

CBS

0.6

PBN

1.0

Sulphur

3.2


200


15

Appendix 1

Styrene Butadiene Rubber Ingredient

Amount (pphr)

Compound E - General Purpose

SBR 1500

100


HAF black

50

Stearic acid

2


4.5

Zinc oxide

3

CBS

1.0

PBN

1.0

Sulphur

1.75

Compound F - Good Ageing

SBR 1500

100


HAF black

50

Stearic acid

2


4.5

Zinc oxide

3

TMTD

3

PBN

1.0

MBTS

1.0

Compound G - General Purpose

SBR 1710

100


HAF black

50

Stearic acid

2


4.5

Zinc oxide

3

CBS

1.0

PBN

1.0

Sulphur

1.75

Compound H - Good Ageing

SBR 1710

100


HAF black

50

Stearic acid

2


4.5

Zinc oxide

3

TMTD

3

PBN

1.0

MBTS

1.0

16


Butyl Rubber

Butyl Rubber Ingredient

Amount (pphr)

Compound J - General Purpose

Polysar 301 (high unsaturation)

100


FEF black

50

Zinc oxide

5

Stearic acid

2

MBT

0.5

TMT

1.0

Sulphur

2

Compound K - Good Ageing

Polysar 100 butyl (low unsaturation) 100


HAF black

50

Zinc oxide

25

Sulphur

2

MBTS

4

GMF

2


17

Appendix 1

Polychloroprene Ingredient

Amount (pphr)

Compound L - General Purpose

Neoprene type WRT

100


Light calcined magnesia

4

PBN

2

Stearic acid

0.5

SRF black

40


5

Robac 22

0.75

Zinc oxide

5

Compound M - Natural Ageing

Neoprene type WRT

100



4

Akroflex CD

2

Stearic acid

0.5

SRF black

50


5

DOTG

0.75

TMT-MS

0.75

Sulphur

0.75

Zinc oxide

5

Compound N - Heat Ageing

Neoprene type WRT

100



4

Aranox

0.5

Akroflex CD

2

Octamine

3.5

Stearic acid

0.5

SRF black

30


90

Low volatile process oil

8

Robac 22

1

Zinc oxide

25

18


Nitrile Rubber

Nitrile Rubber

Compound P - General Purpose

Ingredient

Amount (pphr)

Nitrile rubber

100


Compound R - Good Ageing

ca. 32-34% acrylonitrile) SRF black

50

DOP

20

Zinc oxide

5

Stearic acid

1

PBN

1

MBTS

1.5

Sulphur

1.5

Nitrile rubber

100


(ca. 35% acrylonitrile) SRF black

50

DOP

10

Polypropylene adipate

10

Zinc oxide

5

Stearic acid

1

Flectol H

2

TMTD

3

CBS

3


19

Appendix 1

Miscellaneous Ingredient

Amount (pphr)

Compound S - Acrylate Rubber

Hycar 4021

100


SRF black

50

Stearic acid

1

Triethylene tetramine

2

TMTM

1

Sulphur

3

Compound T -

Hypalon 20

100

Chlorosulphonated polyethylene


45


Hydrogenated wood rosin

5

Litharge

20

MBTS

0.5

Flectol H

2

Process oil

10

Robac P25

0.75


10

Compound W - Polysulphide Rubber

Thiokol St

100


SRF black

60

Stearic acid

3

GMF

1.5

Zinc oxide

0.5

Dimethyl silicone gum (slightly unsaturated)

100

Diatomaceous silica

45

Fine silica

36

Ferric oxide

1

2,4-dichlorobenzoyl peroxide in silicone fluid

2

Compound X - Silicone Rubber Curing conditions: 10' @ 135 °C Post cure 1 h @ 150 °C, 24 h @ 250 °C in air

20


New Compounds

New Compounds Ingredient

Amount (pphr)

Compound N1 - FVMQ

Silastic LS 238 OU

100

Curing conditions: 10' @ 171 °C,

Slastic HT-1

1

Post cure 4 h @ 200 °C in air

DHBP (50% silicone oil)

0.9

Compound N2 - HNBR

Zetpol 2000L

100


Spheron 4000

60

Naugard 445

1.5

Rhenogran ZMMBI 50

3

Zinc Oxide Active

3

Peroximon F40

8

Compound N3 - Epoxidised natural

Based on Epoxyprene 50, low

Curing conditions: 23.5' @ 141 °C

black loading, sulphur, TMTD, CBS and stabilised. Details confidential.

Compound N4 - Chlorinated polyethylene

Tyrin CM 3630

100


Flectol pastilles

0.2

Maglite DE

10

SRF N772 black

60

FEF N550 black

50

Britomya BSH

20

Bisoflex TOT

35

Drapex 39

4

Perkadox 14/40

6.25

Rhenogran TAC 50

5.6

Compound N5 - Fluorocarbon

Viton A-202C

100

Curing conditions: 20' @ 170 °C,

MT N990 Black

20

Post cure 24 h @ 225 °C in air

Sturge VE

6

Maglite DE

3

Compound N6 - Exxpro

Exxpro MDX90-10

100


HAF N330 Black

50

Stearic Acid

2

Zinc oxide

0.5

Tetrone A

1


21

Appendix 1

New Compounds (continued) Ingredient

Amount (pphr)

Compound N7 - Epichlorohydrin

Hydrin C65

100


SRF N772 black

70

Winnofil S

5

Paraplex G50

5

DOP

5

Vulkanox MB

1

Stearic acid

1

Span 60

1

Zisnet F

1

DPG

0.3

Maglite DE

5

Compound N8 - EPDM

Vistalon 7000

100


Zinc Oxide

10

Stearic Acid

2

SRF N772 Black

45

FEF N550 Black

60

Strukpar 2280

59

Sulphur

1

TMTD

2.5

ZDMC

2.67

NDBC

2

Sulfasan R

1.7

Compound N9 - EVA

Levapren 400

100


Staboxal PCD

3

Post cure 2 h @ 165 °C in steam

Zinc stearate

2

Vulkanox DDA

1

FEF N550 Black

30

Mistron Vapour

50

Perkadox 14/40

6

TAC

4

Compound N10 - PU

Adiprene FM

100


FEF N550 Black

40

DBP

5

Stearic Acid

1

Dicup 40C

3

Rhenogran TAC50

2

22


Participant’s Compounds

Participant's Compounds Details of most of the formulations are not disclosed. Compound P1

Blend of two EPDM copolymers, one with high ethylene content and medium Mooney viscosity, the other with medium ethylene content and low Mooney viscosity. Contains carbon black, zinc oxide, TMQ, paraffinic process oil, dicumyl peroxide and a sulphur donor.

Compound P2

Silicone gum blended to give a methylvinylsiloxane content of 0.31% Silicone processing aid Precipitated silica Fumed silica Vinyl specific peroxide Urea

Compound P8

Natural rubber Activators Fillers Process aids 6PPD TMQ Antiozonant wax Sulphenamide TMTM Sulphur

100 7 105 50 3 2 4 0.75 0.1 1.5

(pphr)

Compound P10

NBR (28% ACN) Mineral fillers Silica Zinc oxide Stearic acid Antioxidants Sulphur cure system

100 100 25 10 1

(pphr)


23

24


APPENDIX 2 WEATHERING RESULTS


25

26


Natural Rubber - Standard

Compound A (natural rubber - standard) Table 1. Property changes after 6 months' exposure Property

Weathering Period Initial

After 6 months' exposure

Difference

% Change

75

81

5.8

8

Tensile Strength (MPa)

29.3

21.7

-7.6

-26

Elongation at Break (%)

516

32 7

-189

-37

Modulus at 100% (MPa)

3.38

5.03

1.65

49


15.7

20.2

4.5

29

Hardness (IRHD) Tensile Properties

Compound A (natural rubber - standard) Table 2. Estimated changes after 6 months at 45 °C Property

% Change after 6 months of weathering

% Change after 6 months at 45 °C

% Change due to weathering effects alone

% Change due to 10 years in UK

7.7

10.7

-3

-4


-25.9

-15.7

-10

-1 5


-36.6

-42.4

6

8


48.8

11.2

38

54


28.7

10.8

18

26



27

Compound A

Hardness Compound A 86

84

Hardness (Micro-IRHD)

82

80

78

76

74

72

70 0

30

60

90

120

150

180

120

150

180

Weathering Period (Days)

Tensile Strength Compound A 32.0

30.0


28.0

26.0

24.0

22.0

20.0

18.0 0

30

60

90 Weathering Period (Days)

28


Natural Rubber - Standard

Elongation at Break Compound A 650

600


550

500

450

400

350

300

250 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound A 10.00


8.00

6.00

4.00

2.00

0.00 0

30

60



29

Compound A

Modulus at 300% Compound A 30.0


25.0

20.0

15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


30


Natural Rubber - Good Ageing

Compound B (natural rubber - good ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

68

72

4.2

6


26.8

21.2

-5.6

-21


608

47 2

-136

-22


1.92

2.08

0.16

8


10.9

11.9

1.0

9


Compound B (natural rubber - good ageing) Table 2. Estimated changes after 6 months at 45 °C Property





6.2

5. 9

0

0


-20.9

0.4

-21

-3 0


-22.4

-24.8

2

3


8.3

67.2

-59

-8 4


8.9

17.4

-8

-1 2



31

Compound B

Hardness Compound B 76

74


72

70

68

66

64

62

60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound B 30.0


28.0

26.0

24.0

22.0

20.0

18.0 0

30

60


32


Natural Rubber - Good Ageing

Elongation at Break Compound B 750

700


650

600

550

500

450

400

350 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound B 4.00


3.00

2.00

1.00

0.00 0

30

60



33

Compound B

Modulus at 300% Compound B 20.0


15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


34


Natural Rubber - Mineral Filler Loaded

Compound C (natural rubber - mineral filler loaded) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

54

58

3.8

7


24.2

11.8

-12.4

-51


644

54 0

-104

-16


1.41

1.30

-0.11

-8


4.63

3.82

-0.81

-17


Compound C (natural rubber - mineral filler loaded) Table 2. Estimated changes after 6 months at 45 °C Property





7.0

0. 0

7

10


-51.2

-3.3

-48

-6 8


-16.1

-3.0

-13

-1 9


-7.8

15.6

-23

-3 3


-17.5

-0.2

-1 7

-2 5



35

Compound C

Hardness Compound C 66 64


62 60 58 56 54 52 50 48 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound C 30.0


25.0

20.0

15.0

10.0

5.0 0

30

60


36


Natural Rubber - Mineral Filler Loaded

Elongation at Break Compound C 750

700


650

600

550

500

450

400 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound C 3.00


2.50

2.00

1.50

1.00

0.50

0.00 0

30

60



37

Compound C

Modulus at 300% Compound C 8.00

7.00


6.00

5.00

4.00

3.00

2.00

1.00

0.00 0

30

60

90

120

150

180


38


Natural Rubber - Mineral Filler (Heavy Loaded)

Compound D (natural rubber - mineral filler (heavy loaded)) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

62

82

21

33


11.3

5.47

-5.8

-52


590

38 5

-205

-35


1.57

1.45

-0.12

-8


4.50

3.95

-0.55

-12


Compound D (natural rubber - mineral filler (heavy loaded)) Table 2. Estimated changes after 6 months at 45 °C Property





33.4

-0.3

34

48


-51.6

-25.6

-26

-3 7


-34.7

-22.7

-12

-1 7


-7.6

29.3

-37

-5 3


-12.2

12.2

-24

-3 5



39

Compound D

Hardness Compound D 100

95


90

85

80

75

70

65

60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound D 14.0


12.0

10.0

8.0

6.0

4.0

2.0 0

30

60


40


Natural Rubber - Mineral Filler (Heavy Loaded)

Elongation at Break Compound D 700 650


600 550 500 450 400 350 300 250 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound D 4.00


3.00

2.00

1.00

0.00 0

30

60



41

Compound D

Modulus at 300% Compound D 8.00

7.00


6.00

5.00

4.00

3.00

2.00

1.00

0.00 0

30

60

90

120

150

180


42


Styrene Butadiene Rubber - General Purpose

Compound E (styrene butadiene rubber - general purpose) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

67

72

5.2

8


26.4

23.1

-3.3

-13


486

36 7

-119

-24


2.66

3.47

0.81

30


14.8

18.4

3.6

24


Compound E (styrene butadiene rubber - general purpose) Table 2. Estimated changes after 6 months at 45 °C Property


% Change after 6 months at 4 5 °C



7.8

9.4

-2

-2


-12.5

-4.5

-8

-1 1


-24.5

-30.7

6

9


30.5

60.9

-30

-4 3


24.3

43.9

-20

-2 8



43

Compound E

Hardness Compound E 80 78 76


74 72 70 68 66 64 62 60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound E 32.0


30.0

28.0

26.0

24.0

22.0

20.0 0

30

60


44



Elongation at Break Compound E 600


550

500

450

400

350

300 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound E 6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



45

Compound E

Modulus at 300% Compound E 30.0


25.0

20.0

15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


46


Styrene Butadiene Rubber - Good Ageing

Compound F (styrene butadiene rubber - good ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

64

66

1.9

3


27.2

21.4

-5.8

-21


589

48 3

-106

-18


1.93

2.00

0.07

4


11.3

11.2

-0.10

-0.9


Compound F (styrene butadiene rubber - good ageing) Table 2. Estimated changes after 6 months at 45 °C Property





3.0

5. 8

-3

-4


-21.3

-8.5

-13

-1 8


-18.0

-9.8

-8

-1 2


3.6

37.8

-34

-4 9


-0.9

22.1

-23

-3 3



47

Compound F

Hardness Compound F 70 69 68


67 66 65 64 63 62 61 60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound F 30.0


28.0

26.0

24.0

22.0

20.0

18.0 0

30

60


48



Elongation at Break Compound F 700


650

600

550

500

450

400 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound F 4.00


3.00

2.00

1.00

0.00 0

30

60



49

Compound F

Modulus at 300% Compound F 20.0


15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


50



Compound G (styrene butadiene rubber - general purpose) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

64

70

5.9

9


21.8

19.1

-2.7

-12


563

43 3

-130

-23


1.84

2.31

0.47

26


9.64

12.3

2.66

28


Compound G (styrene butadiene rubber - general purpose) Table 2. Estimated changes after 6 months at 45 °C Property





9.2

7. 2

2

3


-12.4

-12.4

0

0


-23.1

-28.2

5

7


25.5

53.3

-28

-4 0


27.6

41.1

-14

-1 9



51

Compound G

Hardness Compound G 74

72


70

68

66

64

62

60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound G 24.0


22.0

20.0

18.0

16.0 0

30

60


52



Elongation at Break Compound G 700

650


600

550

500

450

400

350 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound G 4.00


3.00

2.00

1.00

0.00 0

30

60



53

Compound G

Modulus at 300% Compound G 20.00


15.00

10.00

5.00

0.00 0

30

60

90

120

150

180


54



Compound H (styrene butadiene rubber - good ageing) Table 1. Property changes after six months' exposure Property



Difference

% Change

59

62

3.1

5


20.6

16.0

-4.6

-22


604

54 3

-61

-10


1.44

1.37

-0.07

-5


8.34

7.64

-0.70

-8


Compound H (styrene butadiene rubber - good ageing) Table 2. Estimated changes after 6 months at 45 °C Property





5.3

7. 6

-2

-3


-22.3

-12.3

-10

-1 4


-10.1

-42.9

33

47


-4.9

49.3

-54

-7 7


-8.4

81.1

-89

-12 8



55

Compound H

Hardness Compound H 65 64 63


62 61 60 59 58 57 56 55 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound H 24.0


22.0

20.0

18.0

16.0

14.0

12.0 0

30

60


56



Elongation at Break Compound H 750

700


650

600

550

500

450

400

350 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound H 3.00


2.50

2.00

1.50

1.00

0.50

0.00 0

30

60



57

Compound H

Modulus at 300% Compound H 14.00

12.00


10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


58


Butyl Rubber - General Purpose

Compound J (butyl rubber - general purpose) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

67

67

0.4

0.6


12.7

12.3

-0.4

-3


419

41 2

-7

-2


2.62

2.56

-0.06

-2


9.64

9.52

-0.12

-1


Compound J (butyl rubber - general purpose) Table 2. Estimated changes after 6 months at 45 °C Property





0.6

-1.5

2

3


-3.1

-3.1

0

0


-1.7

-8.1

6

9


-2.3

11.1

-13

-1 9


-1.2

0.0

-1

-2



59

Compound J

Hardness Compound J 72 71 70


69 68 67 66 65 64 63 62 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound J 15.0


14.0

13.0

12.0

11.0

10.0 0

30

60


60


Butyl Rubber - General Purpose

Elongation at Break Compound J 500


450

400

350

300 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound J 5.00


4.00

3.00

2.00

1.00

0.00 0

30

60



61

Compound J

Modulus at 300% Compound J 16.00

14.00


12.00

10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


62


Butyl Rubber - Good Ageing

Compound K (butyl rubber - good ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

79

80

0.6

0.8


14.0

13.4

-0.6

-4


614

55 9

-55

-9


2.12

2.16

0.04

2


6.72

6.95

0.23

3


Compound K (butyl rubber - good ageing) Table 2. Estimated changes after 6 months at 45 °C Property





0.8

5. 8

-5

-7


-4.3

-13.6

9

13


-9.0

-21.8

13

18


1.9

16.0

-14

-2 0


3.4

0.0

3

5



63

Compound K

Hardness Compound K 85 84 83


82 81 80 79 78 77 76 75 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound K 17.0

16.0


15.0

14.0

13.0

12.0

11.0

10.0 0

30

60


64


Butyl Rubber - Good Ageing

Elongation at Break Compound K 750


700

650

600

550

500

450 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound K 4.00


3.00

2.00

1.00

0.00 0

30

60



65

Compound K

Modulus at 300% Compound K 12.00


10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


66


Polychloroprene - General Purpose

Compound L (polychloroprene - general purpose) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

69

73

3.6

5


21.6

18.9

-2.7

-13


318

26 9

-49

-15


3.91

4.32

0.41

10


21.0

20.9

-0.10

-0.5


Compound L (polychloroprene - general purpose) Table 2. Estimated changes after 6 months at 45 °C Property





5.2

1. 4

4

5


-12.5

0.0

-13

-1 8


-15.4

-5.7

-10

-1 4


10.5

-4.1

15

21


-0.5

0.5

-1

-1



67

Compound L

Hardness Compound L 80

78


76

74

72

70

68

66

64 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound L 26.0


24.0

22.0

20.0

18.0

16.0

14.0 0

30

60


68


Polychloroprene - General Purpose

Elongation at Break Compound L 400


350

300

250

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound L 7.00

6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



69

Compound L

Modulus at 300% Compound L 30.0


25.0

20.0

15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


70


Polychloroprene - Natural Ageing

Compound M (polychloroprene - natural ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

69

74

5.0

7


20.7

19.3

-1.4

-7


332

29 6

-36

-11


4.00

4.49

0.49

12


18.7

19.7

1.0

5


Compound M (polychloroprene - natural ageing) Table 2. Estimated changes after 6 months at 45 °C Property





7.2

6. 2

1

1


-6.8

-4.8

-2

-3


-10.8

-8.1

-3

-4


12.3

7. 0

5

8


5.3

5.9

-1

-1



71

Compound M

Hardness Compound M 80

78


76

74

72

70

68

66

64 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound M 26.0


24.0

22.0

20.0

18.0

16.0

14.0 0

30

60


72


Polychloroprene - Natural Ageing

Elongation at Break Compound M 400


350

300

250

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound M 6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



73

Compound M

Modulus at 300% Compound M 30.0


25.0

20.0

15.0

10.0

5.0

0.0 0

30

60

90

120

150

180


74


Polychloroprene - Heat Ageing

Compound N (polychloroprene - heat ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

80

91

11

14


10.3

8.12

-2.2

-21


368

28 4

-84

-23


2.89

4.19

1.3

45


8.28

8.54

0.26

3


Compound N (polychloroprene - heat ageing) Table 2. Estimated changes after 6 months at 45 °C Property





13.6

3.5

10

14


-21.2

0.0

-21

-3 0


-22.8

-4.9

-18

-2 6


45.0

27.0

18

26


3.1

4. 6

-1

-2



75

Compound N

Hardness Compound N 96 94 92


90 88 86 84 82 80 78 76 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound N 12.0


11.0

10.0

9.0

8.0

7.0

6.0 0

30

60


76


Polychloroprene - Heat Ageing

Elongation at Break Compound N 450


400

350

300

250

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound N 6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



77

Compound N

Modulus at 300% Compound N 14.00

12.00


10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


78


Nitrile Rubber - General Purpose

Compound P (nitrile rubber - general purpose) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

55

59

3.7

7


17.4

16.6

-0.8

-5


531

44 4

-87

-16


1.86

2.01

0.15

8


8.8

10.7

1.9

22


Compound P (nitrile rubber - general purpose) Table 2. Estimated changes after 6 months at 45 °C Property





6.7

11.8

-5

-7


-4.6

11.5

-16

-2 3


-16.4

-32.4

16

23


8.1

29.6

-22

-3 1


21.6

54.5

-33

-4 7



79

Compound P

Hardness Compound P 64

62


60

58

56

54

52

50 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound P 24.0

22.0


20.0

18.0

16.0

14.0

12.0

10.0 0

30

60


80


Nitrile Rubber - General Purpose

Elongation at Break Compound P 650

600


550

500

450

400

350

300 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound P 4.00


3.00

2.00

1.00

0.00 0

30

60



81

Compound P

Modulus at 300% Compound P 16.00

14.00


12.00

10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


82


Polychloroprene - Good Ageing

Compound R (polychloroprene - good ageing) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

55

60

5.1

9


23.1

17.2

-5.9

-26


650

50 9

-141

-22


1.67

1.85

0.18

11


7.37

8.86

1.5

20


Compound R (polychloroprene - good ageing) Table 2. Estimated changes after 6 months at 45 °C Property





9.3

17.6

-8

-1 2


-25.5

-

-

-


-21.7

-55.1

33

48


10.8

63.5

-53

-7 5


20.2

34.2

-14

-2 0



83

Compound R

Hardness Compound R 66

64


62

60

58

56

54

52 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound R 26.0


24.0

22.0

20.0

18.0

16.0

14.0 0

30

60


84


Nitrile Rubber - Good Ageing

Elongation at Break Compound R 750

700


650

600

550

500

450

400 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound R 4.00


3.00

2.00

1.00

0.00 0

30

60



85

Compound R

Modulus at 300% Compound R 14.00

12.00


10.00

8.00

6.00

4.00

2.00

0.00 0

30

60

90

120

150

180


86


Miscellaneous - Acrylate Rubber

Compound S (miscellaneous - acrylate rubber) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

52

52

0.4

0.8


11.3

11.6

0.3

3


223

241

18

8


3.47

3.18

-0.29

-8


-

-

-

-


Compound S (miscellaneous - acrylate rubber) Table 2. Estimated changes after 6 months at 45 °C Property





0.8

0. 0

1

1


2.7

-19.7

22

32


8.1

-13.5

22

31


-8.4

-0.9

-7

-1 1


-

-

-

-



87

Compound S

Hardness Compound S 60

58


56

54

52

50

48

46 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound S 14.0


13.0

12.0

11.0

10.0

9.0 0

30

60


88


Miscellaneous - Acrylate Rubber

Elongation at Break Compound S 300

280


260

240

220

200

180

160 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound S 6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



89

Compound S

90


Miscellaneous - Chlorosulphonated Polyethylene

Compound T (miscellaneous - chlorosulphonated polyethylene) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

53

67

14

27


8.00

6.00

-2.0

-25


438

26 3

-175

-40


2.88

3.99

1.1

39


6.27

5.23

-1.0

-17


Compound T (miscellaneous - chlorosulphonated polyethylene) Table 2. Estimated changes after 6 months at 45 °C Property





26.6

11.7

15

21


-25.0

27.5

-53

-7 5


-40.0

-37.4

-3

-4


38.5

-2.1

41

58


-16.6

-

-

-



91

Compound T

Hardness Compound T 75


70

65

60

55

50 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound T 10.0


9.0

8.0

7.0

6.0

5.0

4.0 0

30

60


92


Miscellaneous - Chlorosulphonated Polyethylene

Elongation at Break Compound T 500


450

400

350

300

250

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound T 6.00


5.00

4.00

3.00

2.00

1.00

0.00 0

30

60



93

Compound T

Modulus at 300% Compound T 10.0 9.0 8.0


7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 0

30

60

90

120

150

180


94


Miscellaneous - Polysulphide Rubber

Compound W (miscellaneous - polysulphide rubber) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

63

70

7.3

12


5.69

5.32

-0.37

-7


310

24 7

-63

-20


2.01

2.43

0.42

21


-

-

-

-


Compound W (miscellaneous - polysulphide rubber) Table 2. Estimated changes after 6 months at 45 °C Property





11.6

11.0

1

1


-6.5

-1.6

-5

-7


-20.3

-12.9

-7

-1 1


20.9

19.9

1

1


-

-

-

-



95

Compound W

Hardness Compound W 76

74


72

70

68

66

64

62

60 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound W 8.0


7.0

6.0

5.0

4.0

3.0 0

30

60


96


Miscellaneous - Polysulphide Rubber

Elongation at Break Compound W 340

320


300

280

260

240

220

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound W 4.00


3.00

2.00

1.00

0.00 0

30

60



97

Compound W

98


Miscellaneous - Silicone Rubber

Compound X (miscellaneous - silicone rubber) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

54

55

1.2

2


7.03

7.16

0.13

2


219

239

20

9


2.89

2.65

-0.24

-8


-

-

-

-


Compound X (miscellaneous - silicone rubber) Table 2. Estimated changes after 6 months at 45 °C Property





2.2

0. 0

2

3


1.8

-0.1

2

3


9.1

-8.2

17

25


-8.3

-1.4

-7

-1 0


-

-

-

-



99

Compound X

Hardness Compound X 60


58

56

54

52

50 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound X 9.0


8.0

7.0

6.0

5.0 0

30

60


100


Miscellaneous - Silicone Rubber

Elongation at Break Compound X 300

280


260

240

220

200

180

160

140 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound X 5.00


4.00

3.00

2.00

1.00

0.00 0

30

60



101

Compound X

102


New Compound - FVMQ

Compound N1 (FVMQ) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

72

72

0.0

0


7.5

7. 1

-0.4

-5


168

17 6

8

5


4.29

4.03

-0.26

-6


-

-

-

-


Compound N1 (FVMQ) Table 2. Estimated changes after 6 months at 45 °C Property





0.0

-1.4

1

2


-5.2

-2.7

-3

-4


4.9

1.2

4

5


-6.1

48.7

-55

-7 8


-

-

-

-



103

Compound N1

Hardness Compound N1 76

75


74

73

72

71

70

69

68 0

30

60

90

120

150

180

150

180


Tensile Strength Compound N1 10.00


9.00

8.00

7.00

6.00

5.00 0

30

60

90

120


104


New Compound - FVMQ

Elongation at Break Compound N1 220


200

180

160

140

120 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound N1


6.00

5.00

4.00

3.00 0

30

60



105

Compound N1

106


New Compound - HNBR

Compound N2 (HNBR) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

68

71

3.2

5


21.3

21.0

-0.2

-1


563

53 9

-24

-4


2.68

2.87

0.19

7


14.3

15.9

1.7

12


Compound N2 (HNBR) Table 2. Estimated changes after 6 months at 45 °C Property





4.7

30.9

-26

-3 7


-1.0

23.5

-24

-3 5


-4.3

3.2

-7

-1 1


7.1

941.0

-934

-133 4


11.6

-2.1

14

20



107

Compound N2



73

71

69

67

65 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound N2


24.0

22.0

20.0

18.0 0

30

60


108


New Compound - HNBR



600

550

500

450

400 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound N2 5.00


4.00

3.00

2.00

1.00 0

30

60



109

Compound N2



18.0

16.0

14.0

12.0

10.0 0

30

60

90

120

150

180


110


New Compound - Epoxidised Natural

Compound N3 (epoxidised natural) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

55

60

4.9

9


24.8

21.5

-3.3

-13


600

50 5

-95

-16


1.87

1.98

0.11

6


6.71

8.98

2.27

34


Compound N3 (epoxidised natural) Table 2. Estimated changes after 6 months at 45 °C Property





8.9

7. 3

2

2


-13.2

-83.8

71

10 1


-15.8

-76.3

61

86


5.9

27.3

-21

-3 1


33.8

44.6

-11

-1 5



111

Compound N3



62

60

58

56

54

52 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound N3


30.0

25.0

20.0

15.0 0

30

60


112


New Compound - Epoxidised Natural



650

600

550

500

450

400 0

30

60

90

120

150

180

120

150

180




2.50

2.00

1.50

1.00 0

30

60



113

Compound N3



10.00

8.00

6.00

4.00 0

30

60

90

120

150

180


114


New Compound - Chlorinated Polyethylene

Compound N4 (chlorinated polyethylene) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

85

88

3.2

4


15.0

13.4

-1.5

-10


196

18 1

-15

-8


8.07

8.37

0.30

4


-

-

-

-


Compound N4 (chlorinated polyethylene) Table 2. Estimated changes after 6 months at 45 °C Property





3.8

0. 0

4

5


-10.2

-0.7

-10

-1 4


-7.7

5.1

-13

-1 8


3.7

14.1

-10

-1 5


-

-

-

-



115

Compound N4



90

88

86

84

82 0

30

60

90

120

150

180

120

150

180




18.0

16.0

14.0

12.0

10.0 0

30

60


116


New Compound - Chlorinated Polyethylene



250

200

150

100 0

30

60

90

120

150

180

120

150

180




10.00

8.00

6.00

4.00 0

30

60



117

Compound N4

118


New Compound - Fluorocarbon

Compound N5 (fluorocarbon) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

71

74

3.4

5


12.9

12.6

-0.3

-2


218

242

24

11


5.22

5.08

-0.14

-3


-

-

-

-


Compound N5 (fluorocarbon) Table 2. Estimated changes after 6 months at 45 °C Property





4.8

-2.8

8

11


-2.3

-0.8

-2

-2


10.9

0.0

11

16


-2.7

-0.2

-2

-4


-

-

-

-



119

Compound N5


78


76

74

72

70

68

66 0

30

60

90

120

150

180

120

150

180




14.0

13.0

12.0

11.0

10.0 0

30

60


120


New Compound - Fluorocarbon



260

240

220

200

180 0

30

60

90

120

150

180

120

150

180



6.50


6.00

5.50

5.00

4.50

4.00

3.50

3.00 0

30

60



121

Compound N5

122


New Compound - Exxpro

Compound N6 (Exxpro) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

67

71

3.5

5


18.1

17.2

-0.9

-5


215

237

22

10


6.70

5.22

-1.48

-22


-

-

-


Compound N6 (Exxpro) Table 2. Estimated changes after 6 months at 45 °C Property





5.2

9. 0

-4

-5


-5.0

-22.7

18

25


10.2

-25.6

36

51


-22.1

0.0

-22

-3 2


-

-

-

-



123

Compound N6


74


72

70

68

66

64

62

60 0

30

60

90

120

150

180

120

150

180




19.0

18.0

17.0

16.0

15.0 0

30

60


124


New Compound - Exxpro



260

240

220

200

180 0

30

60

90

120

150

180

120

150

180




8.00

7.00

6.00

5.00

4.00

3.00 0

30

60



125

Compound N6

126


New Compound - Epichlorohydrin

Compound N7 (epichlorohydrin) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

79

84

5.3

7


9.6

9. 6

0

0


299

211

-87

-29


4.47

5.04

0.57

13


-

-

-

-


Compound N7 (epichlorohydrin) Table 2. Estimated changes after 6 months at 45 °C Property





6.7

3. 8

3

4

0.0

1.6

-2

-2


-29.2

-43.1

14

20


12.8

3. 6

9

13


-

-

-

-

Hardness (IRHD) Tensile Properties Tensile Strength (MPa)


127

Compound N7

Hardness Compound N7 90 88 86


84 82 80 78 76 74 72 70 0

30

60

90

120

150

180

150

180




11.00

10.00

9.00

8.00

7.00 0

30

60

90

120


128


New Compound - Epichlorohydrin



350

300

250

200

150

100 0

30

60

90

120

150

180

120

150

180



6.00


5.50

5.00

4.50

4.00

3.50

3.00 0

30

60



129

Compound N7

130


New Compound - EPDM

Compound N8 (EPDM) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

79

79

0.0

0


16.3

15.9

-0.5

-3


365

35 3

-12

-3


4.38

4.24

-0.14

-3


14.0

14.1

0.1

1


Compound N8 (EPDM) Table 2. Estimated changes after 6 months at 45 °C Property





0.0

0. 0

0

0


-2.9

0.6

-3

-5


-3.3

-27.1

24

34


-3.2

34.5

-38

-5 4


1.0

25.7

-25

-3 5



131

Compound N8



82

80

78

76

74 0

30

60

90

120

150

180

120

150

180




18.0

16.0

14.0

12.0 0

30

60


132


New Compound - EPDM



450

400

350

300

250

200 0

30

60

90

120

150

180

120

150

180




5.50

5.00

4.50

4.00

3.50

3.00 0

30

60



133

Compound N8



18.0

16.0

14.0

12.0

10.0 0

30

60

90

120

150

180


134


New Compound - EVA

Compound N9 (EVA) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

79

82

3.2

4


11.7

12.1

0.4

4


173

187

14

8


7.93

8.91

0.98

12


-

-

-

-


Compound N9 (EVA) Table 2. Estimated changes after 6 months at 45 °C Property





4.0

5. 1

-1

-2


3.8

-0.9

5

7


8.0

-6.4

14

21


12.4

-1.3

14

20


-

-

-

-



135

Compound N9



83

81

79

77

75 0

30

60

90

120

150

180

120

150

180




13.0

12.0

11.0

10.0

9.0 0

30

60


136


New Compound - EVA

Elongation at Break Compound N9


250

200

150

100 0

30

60

90

120

150

180

120

150

180




10.00

9.00

8.00

7.00

6.00 0

30

60



137

Compound N9

138


New Compound - PU

Compound N10 (PU) Table 1. Property changes after 6 months' exposure Property



Difference

% Change

74

79

4.6

6


14.7

17.2

2.5

17


195

174

-21

-11


6.24

8.51

2.27

36


-

-

-

-


Compound N10 (PU) Table 2. Estimated changes after 6 months at 45 °C Property





6.2

-39.2

45

65


17.0

-50.7

68

97


-10.8

-50.8

40

57


36.4

-84.0

120

17 2


-

-

-

-



139

Compound N10


84


82

80

78

76

74

72

70 0

30

60

90

120

150

180

120

150

180




18.0

16.0

14.0

12.0 0

30

60


140


New Compound - PU

Elongation at Break Compound N10


250

200

150

100 0

30

60

90

120

150

180

120

150

180



10.00


9.00

8.00

7.00

6.00

5.00

4.00 0

30

60



141

Compound N10

142


Participant Compound - EPR

Compound P1 Table 1. Property changes after 6 months' exposure Property



Difference

% Change

71

71

-0.3

-0.4


13.2

12.0

-1.1

-9


504

556

51

10


2.15

2.10

-0.05

-2


8.47

7.32

-1.15

-14


Compound P1 Table 2. Estimated changes after 6 months at 45 °C Property





-0.4

-1.4

1

1


-8.7

0.8

-9

-1 4


10.2

0.0

10

15


-2.3

291.6

-294

-42 0


-13.6

-

-

-



143

Compound P1

Hardness Compound P1 76 75 74


73 72 71 70 69 68 67 66 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound P1 18.0

17.0


16.0

15.0

14.0

13.0

12.0

11.0

10.0 0

30

60


144


Participant Compound - EPR

Elongation at Break Compound P1 600


550

500

450

400 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound P1 4.00


3.00

2.00

1.00

0.00 0

30

60



145

Compound P1



12.00

10.00

8.00

6.00

4.00 0

30

60

90

120

150

180


146


Participant Compound - Medium Nitrile Rubber




Difference

% Change

83

85

2.0

2


15.7

14.7

-1.0

-7


242

22 8

-14

-6


10.6

9.9

-0.8

-7


-

-

-

-







2.4

4. 8

-2

-3


-6.6

-1.9

-5

-7


-5.7

-35.1

29

42


-7.2

18.9

-26

-3 7


-

-

-

-



147

Compound P3

Hardness Compound P3 90

88


86

84

82

80

78

76 0

30

60

90

120

150

180

120

150

180




17.0

16.0

15.0

14.0

13.0

12.0 0

30

60


148


Participant Compound - Medium Nitrile Rubber


270


260

250

240

230

220

210

200 0

30

60

90

120

150

180

120

150

180


Modulus at 100% Compound P3 15.00 14.00 13.00


12.00 11.00 10.00 9.00 8.00 7.00 6.00 5.00 0

30

60



149

Compound P3

150


Participant Compound - Nitrile Rubber




Difference

% Change

67

67

0.2

0.3


23.7

20.0

-3.7

-15


514

44 3

-71

-14


3.02

3.22

0.2

7


13.1

13.6

0.5

4







0.3

10.4

-10

-1 4


-15.5

-42.2

27

38


-13.9

-69.5

56

79


6.6

39.4

-33

-4 7


4.0

61.8

-58

-8 3



151

Compound P4


72


70

68

66

64

62

60 0

30

60

90

120

150

180

120

150

180




24.0

22.0

20.0

18.0

16.0 0

30

60


152





550

500

450

400

350 0

30

60

90

120

150

180

120

150

180




4.50

4.00

3.50

3.00

2.50

2.00 0

30

60



153

Compound P4



16.0

14.0

12.0

10.0 0

30

60

90

120

150

180


154


Participant Compound - EPDM




Difference

% Change

71

71

0.0

0.0


12.1

13.3

1.2

10


139

150

11

8


6.62

6.09

-0.53

-8


-

-

-

-







0.0

5. 5

-6

-8


9.7

3. 3

6

9


7.8

-23.0

31

44


-8.0

-

-

-


-

-

-

-



155

Compound P5


74


73

72

71

70

69

68

67 0

30

60

90

120

150

180

120

150

180



16.0


15.0

14.0

13.0

12.0

11.0

10.0

9.0 0

30

60


156


Participant Compound - EPDM



180

160

140

120

100 0

30

60

90

120

150

180

120

150

180




8.00

7.00

6.00

5.00

4.00 0

30

60



157

Compound P5

158


Participant Compound - Vamac G




Difference

% Change

78

83

4.9

6


11.6

12.1

0.5

4


233

22 7

-6

-2


7.37

8.25

0.88

12


-

-

-

-







6.3

23.1

-17

-2 4


3.9

0. 0

4

6


-2.4

4.7

-7

-1 0


11.9

42.5

-31

-4 4


-

-

-

-



159

Compound P6


87


85

83

81

79

77

75 0

30

60

90

120

150

180

120

150

180




13.0

12.0

11.0

10.0 0

30

60


160


Participant Compound - Vamac G

Elongation at Break Compound P6


300

250

200

150 0

30

60

90

120

150

180

120

150

180




9.00

8.00

7.00

6.00

5.00 0

30

60



161

Compound P6

162


Participant Compound - W Type Polychloroprene




Difference

% Change

66

73

7.4

11


15.2

12.1

-3.1

-20


307

25 3

-54

-18


3.36

4.04

0.68

20


-

-

-

-







11.2

6. 1

5

7


-20.1

-6.6

-14

-1 9


-17.6

-18.6

1

1


20.2

25.9

-6

-8


-

-

-

-



163

Compound P7


75


73

71

69

67

65

63 0

30

60

90

120

150

180

120

150

180



16.0


15.0

14.0

13.0

12.0

11.0

10.0 0

30

60


164


Participant Compound - W Type Polychloroprene

Elongation at Break Compound P7


350

300

250

200 0

30

60

90

120

150

180

120

150

180




4.50

4.00

3.50

3.00

2.50

2.00 0

30

60



165

Compound P7

166


Participant Compound - Natural Rubber




Difference

% Change

58

69

10.9

19


12.0

9. 4

-2.6

-22


542

38 5

-157

-29


1.00

1.81

0.81

81


5.63

7.16

1.53

27







18.8

1.7

17

24


-21.8

0.8

-23

-3 2


-28.9

-13.1

-16

-2 3


81.0

145.0

-64

-9 1


27.2

-2.3

29

42



167

Compound P8

Hardness Compound P8 73 71


69 67 65 63 61 59 57 55 0

30

60

90

120

150

180

120

150

180




13.0

12.0

11.0

10.0

9.0

8.0 0

30

60


168


Participant Compound - Natural Rubber



550

500

450

400

350

300 0

30

60

90

120

150

180

120

150

180




2.50

2.00

1.50

1.00

0.50

0.00 0

30

60



169

Compound P8



9.00

8.00

7.00

6.00

5.00

4.00 0

30

60

90

120

150

180


170


Participant Compound - Santoprene 101 55 V185




Difference

% Change

68

68

-0.1

-0.1


5.8

4.4

-1.4

-24


460

397

-63

-14


1.98

1.75

-0.23

-12


4.10

3.55

-0.55

-13







-0.1

0.0

0

0


-23.8

2.9

-27

-3 8


-13.7

-

-

-


-11.6

-2.0

-10

-1 4


-13.4

-1.2

-12

-1 7



171

Compound P9


71


70

69

68

67

66

65 0

30

60

90

120

150

180

120

150

180




6.00

5.00

4.00

3.00 0

30

60


172


Participant Compound - Santoprene 101 55 V185



450

400

350

300 0

30

60

90

120

150

180

120

150

180




2.50

2.00

1.50

1.00

0.50 0

30

60



173

Compound P9



5.00

4.00

3.00

2.00 0

30

60

90

120

150

180


174






Difference

% Change

83

91

7.5

9


11.8

6. 7

-5.1

-43


524

41 9

-104

-20


3.19

3.47

0.28

9


5.80

5.43

-0.37

-6







9.0

6. 0

3

4


-43.0

-2.5

-40

-5 8


-19.9

-29.2

9

13


8.8

22.9

-14

-2 0


-6.4

33.1

-39

-5 6



175

Compound P10


92


90

88

86

84

82

80 0

30

60

90

120

150

180

120

150

180


Tensile Strength Compound P10 14.0 13.0


12.0 11.0 10.0 9.0 8.0 7.0 6.0 5.0 0

30

60


176





550

500

450

400

350

300 0

30

60

90

120

150

180

120

150

180




4.50

4.00

3.50

3.00

2.50

2.00 0

30

60



177

Compound P10



8.00

7.00

6.00

5.00

4.00 0

30

60

90

120

150

180


178


Figure 1 Surface cracking of natural rubber Compound C

Figure 2 Surface cracking of natural rubber Compound D


179

180


Ozone Results

APPENDIX 3 OZONE RESULTS


181

Appendix 3

182


Ozone Results

Table 1. Time to Grade 1 cracking (first cracking) at 50 pphm, h Compound reference

Strain level, % 5

10

15

20

30

A

4

4

4

4

4

B

360

4

4

4

4

C

2

2

2

2

2

D

8

8

2

2

2

E

24

2

2

2

2

F

2

2

2

2

2

G

4

4

4

4

4

H

72

8

4

4

4

J

#

#

#

#

57 6

K

#

#

38 4

288

28 8

P

48

2

2

2

2

R

240

456

48

4

4

W

#

#

240

19 2

96

N3

8

2

2

2

2

N7

#

#

#

576

57 6

P3

24

8

2

2

2

P4

360

48

24

16

8

P8

#

#

#

#

264

P10

#

408

72

72

24

# Cracking was never observed


183

184

0

100

200

300

400

500

600

700

A

B

C

D E F G H K

P

Figure 1

Compound References

J

R

W

N3

Ozone Resistance Results at 50 pphm

N7

P3

P4

P8

P10

5% Strain 10% Strain 15% Strain 20% Strain 30% Strain

Appendix 3


Time to first cracking (hours)

Ozone Results

Table 2. Time to Grade 3 cracking at 50 pphm, h Compound reference

Strain level, % 5

10

15

20

30

A

360

#

552

36 0

21 6

B

#

#

600

432

36 0

C

432

216

72

72

72

D

360

360

72

72

48

E

48

8

24

24

24

F

24

8

24

24

48

G

72

16

8

8

8

H

72

48

16

16

16

P

216

192

192

192

12 0

R

#

45 6

96

24

24

N3

48

24

24

16

48

P3

72

24

16

16

16

P4

384

120

72

72

72

P8

#

#

#

#

264

P10

#

#

72

72

72

# Cracking was either never recorded or did not reach Grade 3 level


185

186

0

100

200

300

400

500

600

700

A

B

C D E F H

P

Figure 2

Compound References

G

R

N3


P3

P4

P8

P10


Appendix 3


Time to Grade 3 cracking (hours)

Ozone Results

Table 3. Time to Grade 1 cracking (first cracking) at 200 pphm, h Compound reference

Strain level, % 5

10

15

20

30

A

4

2

2

2

2

B

4

2

2

2

2

C

2

2

2

2

2

D

4

2

2

2

2

J

#

#

#

552

36 0

K

#

#

#

168

12 0

L

144

144

96

72

48

M

#

#

#

192

14 4

N

#

14 4

#

96

96

P

2

2

2

2

2

R

48

16

2

2

2

W

#

96

72

48

48

P4

48

16

8

4

2

P8

#

#

19 2

48

16

P10

#

16

2

2

2

# Cracking was never observed


187

188

0

100

200

300

400

500

600

A

B

C D J K M

N

Figure 3

Compound References

L

P

R


W

P4

P8

P10


Appendix 3


Time to first cracking (hours)

Ozone Results

Table 4. Time to Grade 3 cracking at 200 pphm, h Compound reference

Strain level, % 5

10

15

20

30

A

48

72

48

24

48

B

24

48

24

16

16

C

8

48

48

48

48

D

#

#

16

16

16

L

168

168

144

96

96

M

#

#

#

192

14 4

N

#

14 4

#

96

96

P

2

8

8

8

8

R

48

24

8

4

4

W

#

#

432

432

38 4

P4

72

24

24

24

16

P8

#

#

192

48

16

P10

#

24

8

8

8

# Cracking was either never recorded or did not reach Grade 3 level


189

190

0

50

100

150

200

250

300

350

400

450

500

A

B

C D L N

P

Figure 4

Compound References

M

R


W

P4

P8

P10


Appendix 3


Time to Grade 3 cracking (hours)

Ozone Results

Compound P4 Grade 1 & 3 Cracking at 50 pphm predicted for grade 3

observed for grade 3

predicted for grade 1


40.0 35.0 30.0

Strain (%)

25.0 20.0 15.0 10.0 5.0 0.0 0

100

200

300

400

500

600

700

Time (hours)

Figure 5

Compound W Grade of Cracking at 200 pphm predicted for grade 1


40.0 35.0 30.0

Strain (%)

25.0 20.0 15.0 10.0 5.0 0.0 0

20

40

60

80

100

120

140

160

180

200

Time (hours)

Figure 6


191

Appendix 3

Compound P10 Grade 1 Cracking at 50 pphm predicted for grade 1


40.0 35.0 30.0

Strain (%)

25.0 20.0 15.0 10.0 5.0 0.0 0

100

200

300

400

500

600

700

Time (hours)

Figure 7

192


Ageing of Rubber - Accelerated Weathering and Ozone Test Results

Ageing of Rubber - Accelerated Heat Ageing Test Results

Rubber and Rubber Balloons

Analysis of rubber and rubber-like polymers

Ozone

Accelerated

Accelerated C# 2008 (Accelerated)

Rubber

Accelerated Silverlight 2 (Accelerated)

Handbook of material weathering

Rubber

Accelerated

Accelerated VB 2008 (Accelerated)

Rubber

Rubber

Photochemical Smog and Ozone Reactions

Rubber

Rubber

The Ageing Brain: The Neurobiology and Neuropsychiatry of Ageing

Ozone Chemistry and Technology

Accelerated SQL Server 2008 (Accelerated)

Ageing And Employment Policies Germany (Ageing and Employment Policies)

Ageing and Employment Policies, Spain (Ageing and Employment Policies)

Accelerated Testing and Validation

Blends of Natural Rubber

Physical Testing of Rubber

The Romance Of Rubber

Accelerated Testing and Validation

Accelerated Testing and Validation

Ageing and Employment Policies: Japan (Ageing and Employment Policies)

Ageing of Rubber - Accelerated Weathering and Ozone Test Results

Ageing of Rubber - Accelerated Heat Ageing Test Results

Rubber and Rubber Balloons

Analysis of rubber and rubber-like polymers

Ozone

Accelerated

Accelerated C# 2008 (Accelerated)

Rubber

Accelerated Silverlight 2 (Accelerated)

Handbook of material weathering

Rubber

Accelerated

Accelerated VB 2008 (Accelerated)

Rubber

Rubber

Photochemical Smog and Ozone Reactions

Rubber

Rubber

The Ageing Brain: The Neurobiology and Neuropsychiatry of Ageing

Ozone Chemistry and Technology

Accelerated SQL Server 2008 (Accelerated)

Ageing And Employment Policies Germany (Ageing and Employment Policies)

Ageing and Employment Policies, Spain (Ageing and Employment Policies)

Accelerated Testing and Validation

Blends of Natural Rubber

Physical Testing of Rubber

The Romance Of Rubber

Accelerated Testing and Validation

Accelerated Testing and Validation

Ageing and Employment Policies: Japan (Ageing and Employment Policies)

Recommend Documents