Through the use of accelerators containing higher alkyl substitution, we have been able to attain improved properties of EPDM diene rubber blends. EPDM/NBR blends vulcanized with sulfur cure systems employing these accelerators compete favorably with CR compounds in heat aging; have essentially the same oil resistance level, and exhibit better low temperature properties. These blends are highly ozone resistant, easy processing, and safe. Because of the versatility of meeting a desired combination of properties by variations both in the ratios of NBR to EPDM and in the selection of the particular grade of each elastomer, these blends will fulfill many sophisticated elastomer applications. These accelerators can also be used to provide non-blooming cure systems for EPDM compounds and safer ultrafast cure systems for diene rubber compounds. We feel that this advance in property improvement in diene rubber EPDM blends through the use of these new accelerators is only the beginning of a whole new compounding technique for blending.

The polar epoxides bcganoethyl glycidyl ether, cyanomethyl glycidyl ether, Bchloro-bcyanoethyl glycidyl ether, and 3,4-epoxy valeronitrile were prepared, characterized, and their polymerization reactions studied Novel cyanoethylation of glycidol produced the Bcpanoethyl glycidyl ether in a quantitative yield Reported is the first practicable synthesis of epicyanohydrin, which failed to polymerize.Homo-, co-, and terpolymerizations of the polar &epoxy nitriles with various alkylene oddes were achieved by employing a complex catalyst obtained from an aluminum aLkyl, acetyl acetone, and water. The polymers produced a series of vulcantzable elastomers which displayed an excellent balance of solvent resistance and low temperature flexibility, as well as good ozone resistance. The presence of a third monomer such as ally1 glycidyl ether was required to facilitate rubber vulcanization, However, it was possible to vulcanize homo-and copolymers of B-chloro-P-cyanoethyl glycidyl ether through the pendant chlorine atom. Catalyst efficiency in all cases was poor due to the complexing of the aluminum catalyst by the nitrile function. 1483 Copynghc D 1973 bv Marcel Dckker. Inc. All Rights Rncrvcd. Neither !hit work nor any ppn may be reproduced or vanwntttcd in any form or by any means. electronic or mechanical. IncludIng photocopying, microfilming, and recording, or by any Informarlon storage and retncvai syr tnn, without permisston in wnting from the publisher Downloaded by [McGill University Library] at 16:

1. Car, wheel position, driver, inflation pressure, and shoulder drop have a statistically significant effect upon wear loss and need to bo taken into consideration before material factors affecting wear can be studied. 2. Variations in macrostructure of the polymers are not found to have a significant effect on wear as compared to microstructure variations. 3. At least two material factors control wear loss of tire treads. 4. When polymers are tested near their glass transition temperature (within 80° C), wear loss is dominated by viscoelastic properties. Viscoelastic properties can be related to wear loss through Tg or the combined effect of the cis, trans, vinyl, and styrene content. 5. At higher test temperatures (over 100° C above Tg) wear loss is dominated by a material factor that has a positive correlation with temperature. This is particularly noticeable when treads are worn under mild conditions. However, there is evidence that this wear factor is present at the testing nearer to Tg but is masked by the dominant viscoelastic effect. 6. The combined effect upon wear of the different material factors leads to an optimum wear resistance for any polymer in the butadiene—styrene system in the range of 75°–105° C above the Tg for that polymer. 7. For polymers tested at the same ambient temperature, (T), the effect of viscoelastic properties decreases non-linearly as T−Tg increases. 8. In the range of test severity studied, severity has little effect upon the inter-relationship of material factors. 9. In the range of test temperature where Tg dominates wear loss, skid distance on wet asphalt pavement is inversely related to wear rating.