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1730285 
Journal Article 
COVULCANIZATION AND OZONE RESISTANCE OF NR/EPDM BLENDS 
Vanduin, M; Krans, JCJ; Smedinga, J 
1993 
1 
Kautschuk Gummi Kunststoffe
ISSN: 0022-9520 
46 
6 
445-451 
WOS:A1993LH69600005 
Blends of polydiene rubbers and EPDM might combine both the good mechanical, elastic, and dynamic properties of the former and the oxidation and ozonization resistance of the latter It is demonstrated that the EPDM phase in SMR CV 50/EPDM (70/30) blends with and without carbon black is always well dispersed in the NR matrix (<3 mum). As a result, the static ozone resistance of the NR/EPDM blends is excellent An increase in the Mooney viscosity and/or of the third monomer content of the EPDM results in an increased crosslinking of the EPDM phase, but does not affect the ozone resistance. Various procedures from the (patent) literature have been screened in order to enhance covulcanization. Our experiments show that addition of poly-trans-octenylene rubber or liquid BR, application of maleic anhydride grafted EPDM, or increasing the vulcanization time of the NR/EPDM blends are the only measures, that both improve covulcanization and seem technologically and environmentally feasible. 
NR; EPDM; BLEND; COVULCANIZATION; OZONE RESISTANCE; MORPHOLOGY