Particle size control in dispersion polymerization of polystyrene

Abstract

In a dispersion polymerization process, the reaction mixture starts out as a homogeneous solution and the resulting polymer precipitates as spherical particles, stabilized by a steric barrier of dissolved polymer. The final polymer particle size is determined by the inherent polymer aggregation behaviour under a given set of conditions. In the present study styrene polymerization was studied in various solvents using cellulosic derivatives as the steric stabilizer. Some of these solvents in certain combinations allowed the direct preparation of particles in the micron size and their size distribution appeared to be highly dependent on the monomer–solvent–initiator system. Investigations of these factors have suggested that monodisperse particles up to 12 μm can be prepared in a single step; studies of several systems are delineated.