Influence of coagents on Payne effect of butadiene rubber vulcanizates

Gum vulcanizates exhibit Payne effect and weak strain overshooting behavior, which is usually forgot in rubber industry. Herein the Payne effect of butadiene rubber (BR) vulcanizates is investigated for clarifying the effect of crosslinking density and sol content mediated by using coagent in conjugation with dicumyl peroxide. Toluene extraction and paraffin swelling of the vulcanizates are performed for clarifying the contribution of sol fraction and chains entanglement. The results show that the Payne effect and weak strain overshooting of gum vulcanizates are closely related to effective crosslinking density rather than network defects. This work is helpful for understanding the nonlinear rheological responses of the gum vulcanizates with defective network structure.