COMPREHENSIVE THEORY OF PARTICLE GROWTH IN THE SMITH-EWART INTERVAL-II OF EMULSION POLYMERIZATION SYSTEMS

A mathematical model is developed for describing the time evolution of particle size distribution, (PSD) in the Smith–Ewart Interval II of emulsion polymerizations. By use of an appropriate combination of transforms, the infinite set of partial differential difference equations for the time evolution of particle size is transformed into a single partial differential “wave equation”. It is shown that all the information connected to the growth history of the reacting polymer latex is encapsulated in this equation. General solutions are presented for systems having an average number of radicals per particle either <0.5 or >0.5. In this treatment the contribution of bimolecular termination reactions is explicitly included. The model provides good fitting to experimentally available PSD data of styrene. © 1990, American Chemical Society. All rights reserved.