Effect of carbon nanotubes on the interlaminar and fracture properties of carbon fiber/epoxy composites

Abstract

The average properties of carbon fiber reinforced plastics (CFRPs) depend on the extent of interaction between the fiberand matrix. Any means, therefore, to modify either of the two constituents of CFRPs is the key to design the composite.Carbon nanotubes (CNTs) are often used to tailor the interface/interphase in conventional CFRPs either by mixing thenanotubes in matrix or by growing them on the surface of fiber. However, the incorporation of nanotubes, by either means, may affect the mechanical performance of the matrix and that of the composite as a whole. Experiments are carried out toassess the effect of CNT dispersion on the rate sensitivity of matrix, and the effect of CNT grafting on the averagemechanical properties of laminated composites. For better dispersion and interfacial interaction of nanotubes with matrix,molecular level designing of nanotubes is carried out by way of functionalization. It is found that the ultimate strength ofepoxy composites increases with applied loading rate, and that neat epoxy is more rate sensitive than CNT based epoxynano composites. Significant enhancements are also observed in the interlaminar and fracture properties of CFRPs after theincorporation of grafted nanotubes in the composite.