Adhesive bonding of carbon fiber reinforced composite using UV-curing epoxy resin

Carbon fiber reinforced materials are widely used in a variety of products due to their stiffness, high strength and light weight. However, the strength of fiber reinforced composites will dramatically decrease when they have suffered damage from impact. Therefore, repair is necessary to maintain integrity. In many cases, speed of this repair is paramount. In this work, UV resins adhered to a damaged panel to form a hard patch are considered for fast repair. The challenge in using UV curing resins on carbon fiber reinforced materials is the non-UV transparency of the composite. In this work, a cationic UV epoxy resin is used due to its characteristic of dark polymerization after UV exposure. ASTM lap shear testing showed the shear stress was above 1000 psi. However, the large scale testing failed due to partial curing of adhesive before repair indicating that control in dosing and resin delivery is critical, yet problematic.