Polymerization kinetics

Abstract

The polymerization reaction kinetics of benzoxazine resins is described in this chapter. Polymerization, in polymer chemistry, is the process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains. There are many forms of polymerization and different systems exist to categorize them. The chemistry of the polymerization begins by formation and linear growth of the chain that soon begins to branch and then to cross-link. As the reaction proceeds, the molecular weight increases rapidly and eventually several chains become linked together into networks of infinite molecular weight. The resulting polymer, if properly processed, is a highly cross-linked, three-dimensional infinite network. The nature of the polymerization reactions of a thermosetting polymer or the macroscopic kinetics is very complex in that many reactive processes sometimes occur simultaneously. In addition, reinforcements, fillers, pigments, and other additives are commonly added. Therefore, the understanding of polymerization kinetics contributes to both a better knowledge of process development and an improvement in the quality of the final products related to the structures of the polymer networks. This chapter summarizes the polymerization reaction of epoxy novolac resin by BA-a. The polymerization of a BA-a: EP mixture is characterized by two predominant reactions, as evidenced by the presence of a double peak in the DSC thermograms. The activation energy value of reaction is similar to the activation energy for polymerization of the neat BA-a, supporting reaction as the reaction among the benzoxazine monomers. © 2011 Copyright © 2011 Elsevier B.V. All rights reserved.