Interfacial and Mechanical Properties of Carbon Fiber Reinforced Polycarbonate (PC) Film and PC Fiber Impregnated Composites

Currently, continuous polymer fibers are usually manufactured in versatile forms such as, aramid fiber. In this study, continuous polycarbonate (PC) fiber having the uniform diameter was manufactured from a thermoplastic PC resin using a twin screw extruder. Carbon nanotubes (CNTs) were uniformly dispersed in the PC resin, using a solvent dispersion method. The effect of CNT on the mechanical properties of PC fiber was analyzed statistically, using Weibull distribution, by single PC fiber tensile test. Dynamic contact angle was measured to compare the surface energies of PC fiber and PC-CNT fiber on the water droplet. The difference in the wetting patterns was also observed by injecting a solvent between two fibers. Tensile strength and Young's modulus of the PC fiber was significantly increased by the addition of even a small amount of CNT. This improvement can be attributed to the excellent reinforcing and stress transferring effects of the CNT filler. Composites were made of both types of PC film and PC fiber as a matrix and their impregnation properties were investigated by inspection of photographs of their cross-sections. The mechanical properties of the two-types of composites were also compared by tensile testing. From the cross-sectional fractography and the permeated PC weight, PC fiber type exhibited better impregnation property than the PC film type, and thus resulted in the improved tensile strength.