Material properties and phase behavior of crosslinkable acrylonitrile‐butadiene copolymer/ethylene vinyl acetate/carbon black composites

Abstract Crosslinkable composites of ethylene vinyl acetate copolymer (EVA)/acrylonitrile‐butadiene copolymer (NBR)/carbon black (CB) finds widespread use in industrial applications. Crosslinking and phase behavior and resulting mechanical properties have been reported, but a systematic investigation as a function of varying molecular architecture is still elusive. The present work combines an experimental and theoretical approach to understand the phase morphology and physical properties of crosslinked EVA/NBR/CB polymer composites. Crosslinking behavior is studied by varying the functionality content in the two polymers. A theoretical model was developed to calculate and predict the overall phase behavior of the composites as well as the preferential solubility of the peroxide in the phases. The phase morphology of the immiscible EVA/NBR polymer blend investigated clearly showed two distinct phases with the NBR phase dispersed in the continuous EVA phase and the CB particles tend to reside at the interface. The influence of varying molecular architecture and functionality of the NBR and EVA on material properties was investigated and did not significantly contribute to the crosslinking and tensile behavior of the composites. The mechanical properties were found to correlate with the degree of crosslinking and CB loading.