Synthesis of poly(styreee-co-4-vinylpyrídine) microspheres via dispersion polymerization: effect of the concentration of 4-vineylpyridine

Amphiphilic copolymer microspheres of poly(styrene-co-4-vinylpyridine) were prepared by dispersion polymerization in an alcohol/water medium. The synthesis of ρoly(styrene-co-4-vinylρyridine) microparticles was successfully carried out, and the latexes had a spherical morphology with good monodispersity. The degree of conversion in the early stage of polymerization decreased with increasing 4-vinylpyridine (4VP) monomer content, but the final conversions were similar (>95%). The copolymerization rate decreased with increasing 4VP content, and a broad particle size distribution was observed with 20 wt % 4VP because of the prolonged nucleation time. With the 4VP concentration increasing, the molecular weight of the copolymer microspheres decreased, and the glass-transition temperature of the copolymers increased; this indicated that all the copolymers were random and homogeneous.