Preparation and characteristics of EPDM/NBR rubber blends with BIIR as compatibilizer

Butadiene-acrylonitrile rubber (NBR) was blended with ethylene-propylene-diene rubber (EPDM) in the presence and absence of different amounts of bromobutyl rubber ( BIIR) to be tested as a compatibilizer. The results revealed that 10 phr was the optimum amount of BIIR to get a compatible blend. Dicumyl peroxide (DCP) curing system resulted in EPDM/NBR vulcanizates with better thermal aging resistance than did sulfur vulcanizates. Also DCP produced vulcanizates with the most reduced swelling values both in motor oil and brake fluid. On the other hand, sulfur-curing systems produced EPDM/NBR vulcanizates with much higher mechanical properties than did DCP vulcanizates. The fatigue resistance of the vulcanizates was greatly improved upon blending the two types of rubber. Also, the 25/75 EPDM/NBR blend possessed the highest aged mechanical properties together with good thermal stability.