Cure characteristics and mechanical properties of styrene-butadiene rubber/acrylonitrile butadiene rubber

Blends of styrene butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NBR) were prepared. Sulfur, dicumyl peroxide (DCP) and a combination of sulfur and DCP were used as vulcanizing agents. The effects of blend ratio and vulcanizing systems on the cure characteristics and mechanical properties, such as stress-strain behaviour, Young's modulus, tensile strength, elongation at break and hardness of SBR/NBR blends, were studied. Blends prepared by using sulfur as the vulcanizing agent showed comparatively better mechanical properties. Tensile and tear strengths showed synergism for the blends containing 60% SBR. The morphology of the blends was examined to correlate with observations on mechanical properties by using an optical microscope with special reference to the effects of blend ratio. A relatively co-continuous morphology was observed for 60:40 SBR/NBR composition.