Preparation of Block Copolymers of Vinyl Acetate in. Viscous Poor Solvents

Stable macroradicals of poly(vinyl acetate) were produced by heating vinyl acetate (VAC) and 2% tert-butyl peroxypivalate at 50° C for 96 hr in silicone oil. Block copolymers were produced from these macroradicals by adding a second vinyl monomer and heating at 50° C for an additional 72 hr. The formation of these macroradicals was monitored by yield, dilatometric rate data, and scanning electron micrographs. Poly(vinyl acetate-b-methyl methacrylate), polyvinyl acetate-b-acrylic acid), polyvinyl acetate-b-acrylonitrile), poly(vinyl acetate-b-vinylpyrrolidone), poly(vinyl acetate-b-styrene), and polyvinyl acetate-b-methyl methacrylate-b-styrene) were characterized by yield, selective precipitation, pyrolysis gas chromatograph, and differential scanning calorimetry (DSC).