SELF-VULCANIZABLE TERNARY RUBBER BLEND BASED ON EPOXIDIZED NATURAL-RUBBER, CARBOXYLATED NITRILE RUBBER AND POLYCHLOROPRENE RUBBER .1. EFFECT OF BLEND RATIO, MOLDING TIME AND FILLERS ON MISCIBILITY

Miscibility of the self-vulcanizable ternary blend based on epoxidized natural rubber (ENR), neoprene and carboxylated nitrile rubber (XNBR) depends on blend ratio. Miscibility is attained at an ENR content of 75 parts per 100 parts of neoprene/XNBR blend, irrespective of the neoprene/XNBR blend ratio. At lower ENR content, miscibility depends on neoprene/XNBR blend ratio. At a fixed ENR content, the higher the neoprene content in the neoprene/XNBR blend, the lower is the miscibility in the ternary blend system. Reinforcing fillers, such as silica and carbon black, cause phase separation in a miscible ternary blend. Variation in moulding time does not alter the miscibility, but shifts the glass transition temperature due to change in crosslink density.