KINETICS OF LONG-CHAIN BRANCHING IN EMULSION POLYMERIZATION

A mathematical model for the kinetics of long-chain branching in emulsion polymerization systems was developed. The model takes into account the compartmentalization of the reaction system. Large errors were found when the effect of the compartmentalization of the free radicals was ignored. The model predicts that extremely high molecular weights can be reached when termination occurs by combination, and the extent of the chain transfer to polymer reaction is significant. Extensive propagation to terminal double bonds can lead to gel formation irrespective of the type of bimolecular termination. The model was used to analyze the effect of the monomer addition policy on the molecular weights of the copolymers obtained in the emulsion copolymerization of ethyl acrylate and methyl methacrylate.