Effect of Carbon Nanotube Deposition Time to the Surface of Carbon Fibres on Flexural Strength of Resistance Welded Carbon Fibre Reinforced Thermoplastics Using Carbon Nanotube Grafted Carbon Fibre as Heating Element

摘要

In recent years, carbon fibre reinforced thermoplastics (CFRTP) are expected to be usedas lightweight structural materials for mass-produced vehicles. CFRTP with thermoplastics asmatrix allows us to weld them using melting of matrix by heating. We have been developinga direct resistance heating method, which uses carbon fibres as the resistance heating element.Carbon nanotube (CNT) is expected to be used as additive to FRP and we reported that thefibre/matrix interfacial shear strength was improved by grafting CNT on the surface of carbonfibres and tensile lap-shear strength was improved by using CNT grafted carbon fibre as the heatingelement for welding. For the practical use of CFRTP for structural parts, flexural strength is alsonecessary to be evaluated. In this study, flexural test was carried out to clarify the effect of CNTdeposition time to the surface of carbon fibres on flexural strength of resistance welded CFRTP usingCNT grafted carbon fibre as the heating element. The highest flexural strength was obtained whenCNT10, for which CNT is grafted on the carbon fibres for deposition time of 10 min, was used forthe heating element of resistance welding. In the case of CNT deposition time of 60 min, the lowestflexural strength was obtained because of the poor impregnation of the resin into the carbon fibredue to the excess CNT on the carbon fibres.