Physico-mechanical properties of NBR/CPVC blend vulcanizates and foams

Abstract

Foams were prepared from acrylonitrile-butadiene rubber (NBR)/chlorinated polyvinyl chloride (CPVC) blend compounds using a chemical blowing agent during compression molding. The effect of varying NBR/CPVC blend ratio and the time on the foams were investigated. The curing parameters showed that both the maximum torque and the difference between the maximum and minimum torque decreased with increase of CPVC content. The limiting oxygen index (LOI) of the blend vulcanizate increased with increase of CPVC content, reached up to 30% for the NBR/CPVC blend with blend ratio 50/50. The SEM micrographs of the NBR/CPVC blend indicate semi-compatibility between the blend phases. The NBR/CPVC foams prepared using a chemical blowing agent, showed closed cell structures, which were uniformly distributed across the blend phases. The average cell sizes increased and foam density decreased with increase of CPVC content. Tensile strength and tear strength of both vulcanizates and foams increased with increase CPVC content. Hardness of the foams increased but resilience of the foams decreased with increase of CPVC content. Density, tensile strength, tear strength, and hardness of the foams increased but resilience decreased when the compression molding time of the foam was increased. J. VINYL ADDIT. TECHNOL., 25:182-188, 2019. (c) 2018 Society of Plastics Engineers