Dispersion copolymerization of styrene and other vinyl monomers in polar solvents

Dispersion polymerization is a very attractive method for preparing microme ter-size monodisperse polymer particles. The applications of microspheres h ave been greatly expanded by the use of copolymers. Here, the dispersion co polymerization of styrene and seven other vinyl monomers was carried out in polar solvents. The effect of the different comonomers on the particle siz e was systematically investigated. The particle size first decreased and th en increased with an increasing fraction of acrylamide in the monomer feed, and at a higher fraction of such a comonomer, only a gel-like polymer was obtained. The particle size also increased with the increase in the content s of the hydrophilic comonomers in the monomer mixtures, and the copolymer molecular weight decreased meanwhile. Although the amount of the hydrophobi c comonomer in the monomer mixture changed, the particle size was hardly af fected. (C) 2001 John Wiley & Sons, Inc.