Effects of blend ratio, crosslinking systems and fillers on the morphology, curing behavior, mechanical properties, and failure mode of acrylonitrilebutadiene rubber and poly(ethylene-co-vinyl acetate) blends

Blends of acrylonitrile butadiene rubber (NBR) and poly(ethylene-co-vinyl a cetate) (EVA), with varying proportions of the components, were vulcanized using different crosslinking systems, namely, sulfur (S), dicumyl peroxide (DCP), and a mixed system (S + DCP). Mechanical properties, such as stress- strain behavior, tensile strength, elongation at break, Young's modulus, te nsile set, and tear strength, were studied. The mixed system exhibited bett er mechanical performance than other systems. The tensile and tear fracture surfaces were analyzed under the scanning electron microscope in order to understand the failure mechanism. The variation in properties was correlate d with the morphology of the system. The effect of high-abrasion furnace bl ack (HAF), semireinforcing furnace black (SRF), silica, and clay on the mec hanical properties and failure mechanism of 50/50 blend of NBR-EVA (N50P) h as also been studied. The Kraus equation has been applied to analyze the ex tent of polymer-filler interaction. Applicability of various theoretical mo dels has been investigated to predict the properties of the blend systems. (C) 1999 John Wiley & Sons, Inc.