Mechanical properties of epoxy nanocomposites added with fullerene and milled-graphite nanoparticles: A comparative study

Abstract

In the present work, a comparative study has been made on epoxy nanocomposite samples reinforced with 0.5 wt% of Fullerene (C60) and milled graphite nanoparticles (GrNPs). Both the nano reinforcements were analyzed under FESEM to assess their morphology. FESEM study reveals the spherical-shaped morphology of C60 with fewer defects, whereas GrNPs are found as aggregated with porous structures consisting of stacked and randomly oriented planes. The major challenges to fabricating epoxy nanocomposites with these nano reinforcements are discussed here with the possible remedies. With the aid of a mechanical stirrer, 0.5 wt% percent of C60 and GrNPs are dispersed separately into the viscous epoxy resin followed by vacuum degassing to remove the entrapped air. The degassed mixtures are then poured into a silicone mold followed by room temperature curing to fabricate the test specimens following ASTM standards. The test findings show that adding 0.5 wt% of C60 to the epoxy system increases the tensile strength, Young's modulus, and fracture toughness for the resulting epoxy nanocomposite by 13 %, 16.5 %, and 16 %, respectively, compared to the neat epoxy system. However, adding 0.5 wt% of GrNPs to the epoxy system increases strength and modulus by 2 % and 7 %, respectively, while depressing fracture toughness by 43 %. These findings informed us that pristine C60 are better reinforcement to strengthen epoxy resin compared to the pristine aggregated GrNPs, which rises the stress concentration effect around the reinforcement and initiates micro-cracks within the resin system thereby reducing the fracture toughness