Structural Evolution of Highly Crosslinked Polymer Networks

Abstract

Homopolymerizations of multifunctional monomers produce densely crosslinked polymer networks with structures that are often complex and difficult to characterize. The complexity in the structure arises primarily from the heterogeneous nature of the polymerization such as the formation of microgels. This work presents progress towards developing a better understanding of the highly crosslinked polymer structure through combined experimental and modeling techniques. Electron spin resonance (ESR) spectroscopy was used to examine the concentration and local environment of the radicals, i.e., the fraction of radicals that were trapped and terminate on a long time scale as compared to those which are more mobile and terminate on a shorter time scale. A kinetic gelation simulation was developed to verify the ESR results and provide further information regarding the structural evolution of the network and its heterogeneities.