Tensile, flexural and interlaminar shear strength of carbon fiber reinforced epoxy composites modified by graphene

In order to investigate the effects of different functional groups on graphene on the mechanical behavior of carbon fiber reinforced epoxy composites were fabricated by hand layup technique. In this study, three different variety of functionalized graphene (-NH2, -COOH, and -OH) with varying weight percent (i.e. 0.1, 0.3, and 0.5 wt%) was considered. Tensile, interlaminar, and three-point flexural tests were conducted to evaluate the effects of graphene concentration and fiber stacking sequence (i.e. 0/90 degrees and 0/90/ +/- 45 degrees) on composites. The microstructures of the composites were characterized by a scanning electron microscope. Experimental results showed that pristine and functionalized graphene significantly improved the mechanical properties of carbon fiber epoxy composites. Compared to neat carbon fiber epoxy composites, the maximum tensile strength of 33.34% and 26.35% were noticed for 0/90 degrees-COOH-0.5 and 0/90/ +/- 45 degrees-NH2-0.3 stacked functionalized graphene modified carbon fiber epoxy composites, respectively. Moreover, 48.44% and 59.1% flexural strength were recorded for 0/90 degrees-COOH-0.3 and 0/90/ +/- 45 degrees-OH-0.5 stacked functionalized graphene modified carbon fiber epoxy composites, respectively. Furthermore, maximum interlaminar shear strength (ILSS) of 120.25% was observed for 0/90/ +/- 45 degrees stacked carbon fiber epoxy composites. Finally, the results obtained with graphene as reinforcement filler can cause a significant improvement in the mechanical performance of fiber composites. Henceforth, they can also be considered as a promising candidate for designing composites for structural applications.