Evaluation of the Chain Length Distribution in Free-Radical Polymerization, 2. Emulsion Polymerization

Abstract

Emulsion polymerization is characterized by the segregation of the active chains in the polymer particles, which can strongly affect the kinetics of the process and in particular the chain length distribution (CLD). To correctly take into account these effects, a model has been developed which is constituted by a set of population balance equations based on the well-known concept of distinguished particle distribution. The model has been solved with the discretization technique developed in the first part of the work, which allows the directly evaluation of the CLD. The obtained model has been used to calculate the CLD resulting from complex polymerization kinetic mechanisms, such as, for example, those of living free-radical polymerization. In all cases rather accurate results have been obtained, including situations characterized by bimodal CLDs, where indirect methods, typically based on the method of moments, fail.