Microsuspension polymerization of methyl methacrylate

Microsuspension polymerization kinetics frequently display characteristics of both suspension and emulsion polymerizations. Because the suspension polymer is the desired product, the concurrent formation of emulsion polymer is detrimental to product quality. Emulsion particles possess significantly different size, molecular weight and possibly composition from the suspension product, and can have a pronounced effect on material properties. Methyl methacylate (MMA) suspension polymerizations often become limited around 85-95% conversion, thereby requiring post-reaction processing to remove residual monomer. Conversely, emulsion polymerizations can attain close to 100% monomer conversion. An ideal microsuspension polymerization process yields a homogeneous dispersion of particles of the desired particle size, without any emulsion polymer, and with similar to 100% conversion. This study examines the kinetics of MMA microsuspension polymerization, including effects of particle size and initiator type. A process for achieving similar to 100% conversion while maintaining true suspension polymerization properties is presented.