Application of time-resolved pulse radiolysis technique in the investigation of the mechanism of epoxy resins cationic polymerization

E-beam induced cationic polymerization of epoxy resins is of great interest to industry because it offers many advantages over thermal curing methods. Despite good thermal properties, epoxy-based composites prepared using E-beam curable resins exhibit low compression strength, poor interlaminar shear strength, and low fracture toughness. We have initiated a comprehensive study to investigate the mechanism of cationic polymerization of epoxy resins in an attempt to identify the factors that are responsible for these shortcomings associated with E-beam curable resins. The objective of this investigation is to use pulse radiolysis technique as a tool to identify the reactive intermediates involved in the polymerization process. We have employed pulse radiolysis in conjunction with optical detection and Electron Paramagnetic Resonance (EPR) spectroscopy to elucidate spectral features and the identity of reactive intermediates produced during the cationic polymerization of epoxy resins. The ultimate goal of this study is to identify the parameters that give rise to improved thermal and mechanical properties of the final composite prepared by electron beam curing.