Fabrication of Epoxy Matrix Composites by Electron Beam Induced Cationic Polymerization1

Abstract

This paper describes the use of high-energy electron beam radiation to fabricate high-performance epoxy resin matrix composites. Employing catalytic amounts of diaryliodonium and triarylsulfonium salt photoinitiators, it was found that graphite fiber reinforced composites based on epoxy monomers could be efficiently e-beam cured at room temperature when exposed to e-beam irradiation. A mechanism involving the reduction of the onium salt initiators by e-beam induced free radicals has been proposed. Strong protonic acids generated during the course of this reaction initiate the cationic ring-opening polymerization of the epoxy resins. This chemistry was employed to fabricate high-performance carbon fiber reinforced composites. The mechanical properties of the composites were measured and effects of blends with other epoxy monomers and additional types of particulate fillers were evaluated using various testing methods.