Block Copolymers From Living Emulsion Polymerization: Reactor Operating Strategies and Blocking Efficiency

摘要

Diblock copolymers are generated using xanthate-based RAFT agents in conjunction with emulsion polymerization via stage-wise operations. First, emulsion polymerization is conducted for styrene, methyl acrylate, and butyl acrylate monomers to obtain polymers of specified molar mass. At the second stage, polymers undergo chain extension to produce block copolymers. Linear growth of molecular weight with respect to conversion establishes the living characteristics of the process. Under batch conditions, partly homopoly-mers are produced. Semi-batch operation produces copolymers of higher purity with low polydispersity. The choice of blocking sequence is crucial for reducing the influence of the terminated chains on the distribution sequence of copolymers produced.