Synthesis of polystyrene latex via emulsion polymerization with poly(vinyl alcohol) as sole stabilizer

Compared with low molecular surfactants, poly(vinyl alcohol) (PVA) could afford latexes with particular tackiness as an important property for various applications. However, until now, except for some highly reactive monomers, most of monomers including styrene seldom use PVA as protective colloid in emulsion polymerization. In this work, we used oil-soluble initiator, 2,2 ' -azobisisobutyronitrile, to accelerate the copolymerization of styrene and divinyl benzene in PVA protected colloids and synthesize polystyrene (PS) latex within 50 min at 70 degrees C successfully. The reaction system could remain stable even at the monomer-to-water ratio as high as 1:4, and the polymerization in pseudo-micelles or latex particles was always dominant. The adjustment of the size of the PS latex in the range from 70 to 100 nm was facilely achieved by changing the polymerization temperature, the addition of PVA, or the monomer-to-water ratio. This method was also exploited to synthesize poly(styrene-co-methyl methacrylate) and poly(styrene- co-4-chlorostyrene) latexes, indicating prospects in applications with the advantages of high capacity and broad applicability. (C) 2017 Wiley Periodicals, Inc.