Study on the Damping of EVM Based Blends

The mechanical and damping properties of blends of ethylene-vinyl acetate rubber(VA content >40 wt %) (EVM)/nitrile butadiene rubber (NBR) and EVM/ethylene-propylene-diene copolymer (EPDM), both with 1.4 phr BIPB (bis (tert-butyl peroxy isopropyl) benzene) as curing agent, were investigated by DMA. The effect of polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), and dicumyl peroxide (DCP) on the damping and mechanical properties of both rubber blends were studied. The results showed that in EVM/EPDM/PVC blends, EPDM was immiscible with EVM and could not expand the damping range of EVM at low temperature. PVC was miscible with EVM and dramatically improved the damping property of EVM at high temperature while keeping good mechanical performance. In EVM/NBR/PVC blends, PVC was partially miscible with EVM/NBR blends and remarkably widened the effective damping temperature range from 41.1 degrees C for EVM/NBR to 62.4 degrees C, while CPVC mixed EVM/NBR blends had an expanded effective damping temperature range of 63.5 degrees C with only one damping peak. Curing agents BIPB and DCP had a similar influence on EVM/EPDM blends. DCP, however, dramatically raised the height of tan delta peak of EVM/NBR = 80/20 and expanded its effective damping temperature range to 64.9 degrees C. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1121-1125, 2011