Emulsion homo- and copolymerization of vinyl acetate in the presence of maleic-modified and unmodified silica

The emulsion homo- and copolymerization of vinyl acetate in the presence of maleic-modified and unmodified silica were investigated. The formation of surfactant admicelles onto the silica surface induces a decrease of the surfactant concentration in water. It was shown that an increase of the functionalization degree of the inorganic support led to a decrease of the initiator conversion during homopolymerization. The same effect, along with the increase of the initiator productivity, was caused by the enhancement of the amount of unmodified silica during the copolymerization of vinyl acetate with bis(2-ethylhexyl)maleate. Vinyl acetate copolymerization with the maleic-modified support was suggested by the oxidation phenomenon taking place during the heating of the formed polymers in air and by T-g measurements. (C) 1999 Elsevier Science Ltd. All rights reserved.