▎ 摘　　要

In the present research, the effects of graphene nanosheets (GNS) and graphite nanoplatelets (GNP) on the mechanical properties of epoxy nanocomposites thereof were studied. It was found that GNS have more significant impact on the mechanical properties of the nanocomposites with better properties for GNC with smaller thickness and larger diameter in comparison with GNP. The mechanical properties of nanocomposites with variable contents of GNS and GNP, 0.05, 0.1, 0.25 and 0.5 wt%, dispersed in epoxy resin for different ultra-sonication times were considered. Moreover, the Halpin-Tsai micromechanical model is used to calculate the stiffness of nanocomposites and the results are compared with the experimental ones. The process of nano-fillers dispersion into the matrix is determinant and a non-uniform dispersion and defects in fabrication can cause premature failure in the matrix and prevent suitable properties from being achieved. A significant enhancement in the tensile strength (15.7% for GNS and 14% for GNP) of the nanocomposites was obtained using 0.1 wt% of GNS and GNP. Also, the Young's modulus of nanocomposites was raised by using higher weight percentage of nanoparticles. The effect of GNS particles on increasing the Young's modulus, compared with that achieved with the GNP particles, was more significant.