Entry and exit rate coefficients in emulsion polymerization of styrene

The rate coefficient for entry of radicals into the polymer particles and the radical exit rate coefficient were estimated in seeded emulsion polymerization of styrene. The dependence of both coefficients on the particle size was used in an attempt to discriminate between the models proposed for these coefficients. The results obtained were found to be consistent with a model in which the entry of radicals into the polymer particles occurs by the propagational mechanism and the radicals desorb from the polymer particles by diffusion. A comparison between the estimated values of the coefficients and those calculated theoretically using the equations derived from the corresponding mechanisms was performed.