Investigation of Damage Properties of Woven Carbon-Epoxy Composites Modified with CNT Fillers

Abstract

CNT/CNF grafting at high amount causes a CNT forest around the fiber and this causes significant limitations in composite material production. Due to increased distance between the fibers, local fiber volume fraction decreases within the yarns. Fiber volume fraction was found to decrease by 2.7–6.2% according to CNT/CNF ratio. The results revealed that there were significant decreases in mechanical properties and characteristic strain values where damage initiation and progression of the composite samples produced from carbon nanotubes grown on fabrics. It was found that Young’s modulus values decreased by 15–17%. Characteristic strain values where damage threshold decreased by 36–53%. It was concluded that decreased local fiber volume fraction and low fiber-matrix interface bonding were the main cause for this situation. Moreover, it is believed that the one of the most important factor that might cause these limitations is lack of adequate wetting of fiber surfaces and low fiber-matrix interface bonding.