Kinetics of vinyl acetate emulsion polymerization

The emulsion polymerization of vinyl acetate has generally been considered a special type of reaction that is not covered by the Smith-Ewart theory. Although the number of particles depends on coalescence rates and can not be predicted by this theory, the polymerization rate data are consistent with the general concepts of Smith and Ewart, including reaction primarily inside swollen polymer particles, escape of radicals from particles, and termination of chains inside the particles. Allowing for rapid exchange of radicals following chain transfer leads to a simple equation which fits much of the published data for cases of both very low and very high values of n , the average number of radicals per particle.