Stereospecific polymerization of vinyl acetate in fluoroalcohols

Synthesis of syndiotactic poly(vinyl alcohol)

Abstract

The free-radical polymerization of vinyl acetate (VAc) was carried out in various alcoholic solvents. Fluoroalcohols with a lower pKa and higher bulkiness were effective in enhancing the syndiotactic specificity of the polymerization. The polymerization of VAc in perfluoro-tert-butyl alcohol ((CF₃)₃COH) at -78°C led to a dyad syndiotacticity of 72%, which is the highest value reported for the radical polymerization of vinyl esters. Hydrogen-bonding between the acetyl groups of VAc and polymer and the fluoroalcohol molecule may be responsible for the enhancement of the syndiotactic specific propagation.