Effect of water absorption on the mechanical properties of continuous carbon fibre reinforced polycarbonate composites

Abstract

Carbon fibre reinforced thermoplastics (CFRTP) attract attention due to their excellent features of specific strength, specific modulus, productivity and recyclability in various fields. In this research, polycarbonate (PC) was used as a matrix of CFRTP with high impact strength compared with other plastics. However, at high temperature and high humidity conditions, hydrolyzation of an ester linkage in PC occurs, at the same time crazes and cracks also occur and the mechanical properties of PC deteriorate. Water absorption testing and tensile testing were also carried out to investigate the influence of water absorption on the mechanical properties on the CF/PC composite and PC resin. Single fibre pull-out tests were carried out to investigate the influence of water absorption on CF/PC interfacial shear strength. The water gain of PC was saturated at 0.46%. For the CF/PC composite, water was absorbed not only in the PC resin but also in the fibre/matrix interface. The tensile strength of the PC resin showed a tendency to decrease as the water absorption time increases, while the tensile modulus of PC did not change. The CF/PC composite showed a tendency to decrease for tensile strength and modulus when water absorption time is at 400 hours. The CF/PC interfacial shear strength showed a tendency to decrease as the water absorption time increases.