Low Temperature, In Situ Polymerization of Vinyl Acetate in Silica Containing Emulsion Gels

Abstract

Vinyl acetate (VAc) was polymerized to about 90% conversion in 9 h at 40°C from the colloidal microstructure of the VAc/fumed silica/cetyltrimethylammonium bromide (CTAB) system. The glass transition ( $T_g$ ) of poly(vinyl acetate) (PVAc) polymerized in these emulsion gels with silica was higher ( $T_g={41}^{°}\text{C}$ ) than those of PVAc made from bulk polymerization at 60°C ( $T_g={31}^{°}\text{C}$ ) and the weight average molar mass ( $M_w$ ) was also larger ( $M_w$ about 300 kg/mol) than those from bulk polymerization ( $M_w=125\text{kg}/\text{mol}$ ). Increased $M_w$ , $T_g$ , and lowered processing temperature for these composites could facilitate new applications for PVAc.