Surfactant-free emulsion polymerizations: predictions of the coagulative nucleation theory

Equations are set down for the formation of latex particles in emulsion polymerization systems in the absence of added emulsifier. The model describes the formation of colloidally unstable precursor particles through homogeneous nucleation, followed by their coagulation and propagational growth to form colloidally stable latex particles. Coagulation rates are obtained through DLVO theory and its modifications, with due allowance for the partial attraction that occurs in the coagulation between particles with different radii. Calculations show good agreement with the experimental data of Ottewill and co-workers for the variation of particle number density with initiator concentration and ionic strength.