Effect of Air Oxidation of Carbon Fiber on Interfacial Shear Strength of Carbon Fiber Reinforced Thermoplastics

Abstract

Carbon fiber reinforced thermoplastics (CFRTPs) are expected to be used for the structural parts of automobiles due to their properties, such as high recyclability and ability of secondary process. They are studied for the purpose of improving productivity and reducing costs. Among thermoplastics, PA6 and PP are expected to be used. PA6 is relatively good in adhesion to carbon fiber among thermoplastics, whereas PP is inferior in adhesion to carbon fiber because it has no polarity. As a fiber modification method for improving the fiber matrix interfacial shear strength (IFSS), oxidizing of carbon fiber has developed. In this study, single fiber pull-out tests of CF/PA6 and CF/PP were conducted to clarify the effect of air oxidation of carbon fiber on the IFSS. The effect of temperature on PA6 and the temperature holding time at specimen preparation for PP on the IFSS were also clarified. The IFSS of CF/PA6 was improved by oxidizing carbon fiber, and the IFSS of CF/PP was improved by oxidizing carbon fiber and using PP with MAPP for matrix. For PA6, the test specimen that was prepared at the higher temperature has higher IFSS. For PP, the test specimen that was prepared with longer temperature holding time has higher IFSS.