Enhancing epoxide kinetics and tuning polymer properties using hydroxyl-containing (meth)acrylates in hybrid photopolymerizations

摘要

In order to improve epoxide kinetic outcomes and to control the phase separation that can occur in cationic/freeradical hybrid systems, the cationic activated monomer (AM) mechanism was promoted through a hydroxyl functional group on the (meth)acrylate, covalently bonding (meth)acrylate chains and epoxide networks. The impact of the AM mechanism on the reaction kinetics and physical properties was studied using real-time Raman spectroscopy and dynamic mechanical analysis to compare a hydroxyl-containing acrylate and methacrylate to non-hydroxyl-containing controls. The promotion of the AM mechanism improved epoxide conversion and polymerization rate. The effect on the (meth)acrylate kinetics correlated to the propagation rate of the neat (meth)acrylate. Formulation viscosity did not have a significant impact in these hybrid systems. The presence of the hydroxyl group increased network homogeneity and cross-link density, yet still allowed control of the glass transition temperature in the hybrid systems by varying the ratio of epoxide to (meth)acrylate.