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

Abstract

Blends of acrylonitrile butadiene rubber (NBR) and poly(ethylene-co-vinyl acetate) (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, tensile set, and tear strength, were studied. The mixed system exhibited better 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 correlated with the morphology of the system. The effect of high-abrasion furnace black (HAF), semireinforcing furnace black (SRF), silica, and clay on the mechanical properties and failure mechanism of 50/50 blend of NBR–EVA (N50P) has also been studied. The Kraus equation has been applied to analyze the extent of polymer–filler interaction. Applicability of various theoretical models has been investigated to predict the properties of the blend systems. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2335–2364, 1999