The effect of crystallinity on the mechanical properties of plain woven carbon reinforced composites using polypropylene

Abstract

In this study, the effect of crystallinity on the mechanical properties of carbon fiber reinforced thermoplastics (CFRTP) was investigated. Plain woven carbon fiber was used as reinforcement. Polypropylene (PP) and maleic anhydride modified polypropylene (MAPP) were used as a matrix. The crystallinity of PP was controlled by using heat treatment after hot press molding of CFRTP. The range of crystallinity of PP and MAPP were from 26% to 40%. Flexural and izod impact tests of CFRTP were conducted based on Japanese Industrial Standard (JIS) K 7074 and K 7110, respectively. And double-notched test of CFRTP was conducted. Crystal morphologies of single carbon fiber added thermoplastics were observed by using polarization microscope. As a result, flexural strength and izod impact the value of CFRTP using PP increased with an increase of crystallinity. Flexural strength and izod impact value of CFRTP using MAPP almost did not change with an increase of crystallinity. But interfacial shear strength of CFRTP using MAPP increased with an increase of crystallinity. Crystallizations of PP and MAPP occurred around carbon fiber after heat treatment. Therefore, interfacial adhesion between fiber and resin increased with an increase of crystallinity.