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

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 (Tg) of poly(vinyl acetate) (PVAc) polymerized in these emulsion gels with silica was higher (Tg=41°C) than those of PVAc made from bulk polymerization at 60°C (Tg=31°C) and the weight average molar mass (Mw) was also larger (Mw about 300 kg/mol) than those from bulk polymerization (Mw=125 kg/mol). Increased Mw, Tg, and lowered processing temperature for these composites could facilitate new applications for PVAc