The role of polyvinyl alcohol in emulsion polymerization

Emulsion polymerization of styrene (St) and vinyl acetate (VAc) in the presence of conventional polyvinyl alcohol (PVA), PVA modified with a terminal alkyl group or PVA modified with a terminal thiol group (HS‐PVA) was compared. Whereas stable PVAc latexes were obtained, a stable PSt latex was obtained only in the case of HS‐PVA. From the adsorption isotherms of these PVAs on the surface of PVAc and PSt latex particles, as well as the grafting efficiencies of VAc and St onto HS‐PVA in relation to the stability of the polymerization process, the role of PVA in the emulsion polymerization was discussed.