Molecular Simulation on Cross-linking Reaction of PVC/NBR

Cross-linking mechanism and cross-linking position of polyvinyl chloride(PVC)/nitrile butadiene rubber(NBR) blends were studied using molecular simulation method.Cross-linking behavior of PVC/NBR blends was studied using the free energy,activation energy and heat of reaction,which were calculated by DMol3.Computer simulation results show that through dicumyl peroxide(DCP) initiator,macromolecular radical of NBR are produced by capturing α-methylene hydrogen and double bond addition reaction,which initiates self-cross-linking reaction of NBR.The rate of addition reaction is higher than that of capturing α-methylene hydrogen reaction.DCP can initiate dehydrogenation of PVC chain to produce PVC chain radical to further intiate self-cross-linking reaction,but it cannot produce dechlorinate reaction.PVC and NBR can produce co-cross-linking reaction.The rate of co-cross-linking reaction of NBR and PVC is higher than that of PVC self-cross-linking reaction,and slower than that of NBR self-cross-linking reaction.