Particle State Dependent Radical Desorption and Its Effect on the Kinetics of Emulsion Polymerization

Abstract

Radical desorption from polymer particles is a kinetic event peculiar to the emulsion polymerization process. A careful modeling of this phenomenon is highly valuable in order to achieve accurate predictions of polymerization rate and average properties of molecular weight. In this work, radical desorption is described accounting for an aspect fully neglected in previous modeling literature. Specifically, particle state dependent desorption coefficients are used instead of a single average coefficient, and the corresponding rate expressions are developed and applied to the solution of the well-known Smith–Ewart equations. Parametric model simulations show that the higher level of detail introduced in the description of radical desorption improves the accuracy of the predicted values of the average number of radicals per particle, especially in the cases of high desorption rate and slow reactions in the aqueous phase.