Chain transfer and living functionalization of polymethacrylates by group transfer polymerization using ethyl 2-Phenyl-2-butenoate

A living functionalization method has been investigated for group transfer polymerization (GTP) of poly(alkyl methacrylates) using ethyl 2-phenyl-2-butenoate (EPB). The end-capping reactions of EPB to living trimethylsilyl ketene acetal-ended poly(methyl methacrylate) (PMMA) chain ends have been systematically studied and characterized by SEC, VPO, UV-visible spectrosocopy, ¹H and ¹³c NMR spectroscopy. The results of sequential monomer addition, varying stoichiometry and copolymerization indicate that EPB effects efficient chain end functionalization only at stoichiometric concentrations; chain transfer reactions (chain transfer constant = 0.4) occur with excess EPB and during copolymerization with MMA. Chain transfer reactions (chain transfer constant = 0.1) also occur when copolymerizing ethyl 2-methyl-2-butenoate with MMA.