Fracture investigation of functionalized carbon nanotubes-grown carbon fiber fabrics/epoxy composites

Abstract

Two different morphologies of carbon nanotubes (CNTs)-grown carbon fiber fabrics (CFFs) were successfully prepared by chemical vapor deposition (CVD) at different temperatures. Short-beam method was used to investigate interlaminar shear strength (ILSS) of epoxy composites reinforced by three kinds of CFFs—desized CFFs, CNTs-grown CFFs and functionalized CNTs-grown CFFs. It was found that the morphology of CNTs affected the mechanical properties of composites. The ILSS of epoxy composites reinforced by CFFs with long and sparse CNTs was decreased by 10.4% compared with the desized CFFs/epoxy composites, while the ILSS of epoxy composites reinforced by CFFs with short and dense CNTs was almost unchanged. However, after the CNTs-grown CFFs functionalization, the ILSS of epoxy composites reinforced by CFFs with different CNTs of two morphologies were 13.78% and 23.93% higher than the desized CFFs/epoxy composites, respectively. By comprehensively analyzing the changes in oxygen-containing functional groups on the surface of CFFs, the fracture surface morphology of the composites and the relative hardness modulus distribution at the interface, a schematic model was proposed to explain the failure mechanism.