Effect of accelerator solubility on the curing characteristics and physico-mechanical properties of SBR/NBR blends: correlation with feeding sequence and blend composition

Abstract

The main objective of this study was to investigate how the effect of accelerator solubility in the blend components on the curing characteristics and mechanical properties of blend and its components could be affected by the accelerator feeding sequence to the blend and the blend composition. For this purpose, the properties of styrene-butadiene copolymer rubber (SBR)/acrylonitrile-butadiene copolymer rubber (NBR) (50/50 and 75/25 wt%/wt%) blends cured using the sulfur curing system with only one of accelerators, zinc dibutyldithiocarbamate (ZDBC) and zinc diethyldithiocarbamate (ZDEC), or with a combination of them as well as the properties of the vulcanized components (SBR and NBR) were examined. The EDX results revealed that ZDBC and sulfur are more localized in the SBR phase of SBR/NBR blends, while ZDEC is more located in the NBR phase. The accelerators feeding sequence to the blend in the way that each accelerator was loaded in an appropriate elastomer phase in terms of solubility could improve the curing characteristics and tensile mechanical properties of the blend, especially for 50/50 blend with a co-continuous morphology.