Role of dichlorocarbene modified styrene butadiene rubber in compatibilisation of styrene butadiene rubber and chloroprene rubber blends

A study was conducted on the use of dichlorocarbene modified styrene butadiene rubber (DCSBR) for the compatibilisation of blends of styrene butadiene rubber (SBR) and chloroprene rubber (CR). Stress–strain behaviour, mechanical properties, and low temperature transitions of the blends were examined in order to elucidate the efficiency of the compatibiliser. It was found that effective compatibilisation was achieved when chlorine content of DCSBR was 25% and its dosage was 5 phr (parts per hundred rubber). Thermal analysis by DSC showed that an appreciable extent of molecular level miscibility has been achieved in SBR/CR blends by using DCSBR as a compatibiliser. The formation of interfacial crosslinks in the presence of DCSBR is evident from the cure characteristics and stress–strain isotherms. An increase in tensile strength, tear strength, resilience and hardness and a decrease in compression set was observed when the chlorine content and dosage of the compatibiliser increased from 15% to 25% and 5 phr, respectively. Compatibilised blends showed enhanced mechanical properties in the presence of reinforcing fillers such as HAF carbon black and precipitated silica.