Rheological studies of dynamic vulcanization of butyl rubber and polypropylene blends

Butyl rubber (BR) is blended with polypropylene (PP) in ratios of 92:8, 84:16, 68:32, 50:50, 32:68, 16:84, and 8:92 (w/w) for the study of dynamic vulcanization. It is observed that the cure torque increases with the decrease in BR content up to the ratio of 50:50. No cure torque is observed in the ratios of 16:84 and 8:92 of BR:PP blends as the PP content becomes very high. On comparison of cure rate of the blends, the BR (100%) shows the highest cure rate because of the fast saturation of double bonds present in BR, whereas maximum cure torque, work energy, and totalized torque are observed in the 32:68 BR:PP blend. It is the result of the formation of an interpenetrating network.