Abstract
Fiber reinforced plastics (FRPs) are used in various fields for their light-weigh and their superiority of high specific strength and modulus. However, there are several issues such as their poor heat resistant property for the general vehicles and the constructions, other than the economy and molding process. Recently, Tg-less epoxy resin is developed. Its elastic modulus does not decrease up to a high temperature due to using potassium carboxylate salt as a catalyst. CFRP and GFRP with the Tg-less epoxy resin matrix were tried to mold and their mechanical properties for evaluation. The Tg-less epoxy GFRP revealed the high heat resistant property. However, the bending modulus and the strength of the Tg-less epoxy CFRP were lower than those of expected. In this report, we explain that the sizing agent for carbon fibers inhibit the anionic polymerization of the Tg-less epoxy resin on the interfacial surface of the carbon fibers. Then we improve the bending modulus and the strength of the Tg-less epoxy CFRP after washing or neutralizing of the sizing agent on the carbon fibers. Moreover we evaluate creep properties of the Tg-less epoxy CFRP under high temperatures.
