Effect of nanomaterial on mode I and mode II interlaminar fracture toughness of woven carbon fabric reinforced polymer composites

Abstract Carbon fibre reinforced polymer (CFRP) composites exhibit limited fracture toughness due to characteristic of interlaminar fibre-matrix cracking and delamination. This paper described how fracture toughness of CFRP composites can be improved by the addition of nano fillers. The CFRP composite specimens were produced by using an epoxy resin with and without 3% nano fillers. The nano filler materials used were multi-walled carbon nanotubes (MWCNTs), graphene nanoplatelets (GnPs) and carbon blacks (CBs). The specimens were prepared to characterize the mode I, mode II fracture toughness and interlaminar shear strength of neat CFRP/epoxy resin, CFRP/3 wt% MWCNTs/epoxy resin, CFRP/3 wt% GnPs/epoxy resin and CFRP/3 wt% CBs/epoxy resin composites, using double cantilever beam (DCB), end-notched flexure (ENF) and short beam shear (SBS) tests. The results indicate that the mode I and mode II interlaminar fracture toughness of neat CFRP composite increases with the addition of MWCNTs and GnPs fillers due to improvements in toughness and stronger interaction between nanoparticles, fibre and matrix. However, CB particle filled CFRP composite had a lower value than the neat CFRP, MWCNTs-CFRP and GnPs-CFRP composites. Also, interlaminar shear strength of CFRP composite increases marginally with the introduction of nano fillers under the short-span three point bend test. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were used to describe the composition of elements and network of cracks.