Fracture behavior of epoxy nanocomposites reinforced with different carbon nano-reinforcements

Mixed mode fracture resistance of epoxy-based nanocomposites reinforced with carbon nanoparticles of three different shapes is studied. The nanodiamond (ND) of spherical shape, the carbon nanofiber (CNF) of cylindrical shape and the graphene oxide (GO) nanoplatelets are used to prepare the nanocomposites. The semi-circular bending specimen (SCB) is employed to perform a total number of 36 mixed mode fracture tests on the prepared nanocomposites. Fracture toughness of nanocomposites having high aspect ratio fillers (i.e. CNF and GO) is found to be higher than that of ND nanocomposites. The fracture mechanisms of nanocomposites and the effect of filler shape on these mechanisms are discussed. In addition, the dispersion state of reinforcements and the fracture surface characteristics are investigated using the photographs taken by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).