Heating properties of carbon fibers subjected to direct resistance heating

Abstract

To mold carbon fiber reinforced thermoplastics (CFRTP), it is necessary to impregnate carbon fiber with thermoplastic resin by heating the materials. Electromagnetic induction heating and direct resistance heating are available heating methods. The electromagnetic induction heating has a high production cost because of the complex equipment used. In contrast, the direct resistance heating is performed with a simple piece of equipment and low power consumption. It is thus better to use direct resistance heating for low-cost CFRTP molding. A process of CFRTP molding is here proposed using direct resistance heating of carbon fibers in non-crimp fabric (NCF). The resistance heating characteristics of NCF and the influence of resistance heating upon mechanical properties of carbon fibers are discussed. The temperature distribution in 0° and 90° layers were found sufficient and it took 70 s to reach 250°C in the temperature history when heat is applied to the NCF [0°/90°] using direct resistance heating. From the results of tensile tests of a single carbon fiber, the tensile strength did not decrease by resistance heating at 300°C for 300 s.