Multiscale Composites of Kevlar Fibers and Carbon Nanotubes in Epoxy Matrix

: Hybrid composites with high strength to weight ratio are very important in structural applications. An extensive research is being carried out to enhance the mechanical properties of composites by incorporating micro and nanoscale reinforcements. The nanoreinforcements provide unique strengthening mechanisms that result in an overall high mechanical performance of composites. In order to investigate the effect of nanoreinforcements on the mechanical properties of fiber reinforced composites a novel multiscale composites of Kevlar fibers and carbon nanotubes in epoxy matrix were prepared in this research. A combination of hand layup and vacuum bagging technique was used to manufacture multiscale composites. Nanotubes at three different concentrations, i.e. 0.33wt%, 0.66wt% and 0.99wt% were incorporated after their functionalization through ultraviolet ozone-treatment to improve their interfacial interaction with epoxy matrix. The microstructural and mechanical property characterization of multiscale composites was performed by optical and electron microscopy, and tensile, hardness and interlaminar shear testing. An increase of ~45% in tensile strength was noted by incorporating 0.99wt% of nanotubes while the improvements of ~60% in hardness and ~13% rise in interlaminar shear strength were observed. The improved mechanical performance owes to the uniform dispersion of nanotubes along with their adherence to nanotubes promoting anchoring effect between fibers and matrix.