Controlled radical polymerization of vinyl acetate in supercritical CO2 catalyzed by CuBr/terpyridine

Poly(vinyl acetate) (PVAc) was synthesized by the atom transfer radical polymerization of vinyl acetate (VAc) in supercritical carbon dioxide using CuBr/2,2':6',2aEuro(3)-terpyridine complex as a catalyst and ethyl 2-bromoisobutyrate as an initiator. Polymerization proceeded in a controlled manner, and low to moderate conversion was achieved within a reasonable time. The effects of the monomer amount, temperature, pressure, initiator, and ligand loading on monomer conversion, molecular weight and molecular weight distribution of the polymer were examined. The reaction kinetics was also investigated. The polymerization reaction was found to be first-order with respect to the monomer concentration. The molecular weights of the resulting PVAc increased linearly with increasing VAc conversion.