Mechanical and thermal properties of carbon fiber reinforced composite with silanized graphene as nano-inclusions

Abstract

The use of nanofillers to enhance the properties of fiber reinforced composites is limited due to the adverse effect on mechanical properties caused by agglomeration of these nanofillers in the matrix materials. In this study, graphene nanoflakes were functionalized with silane moiety to improve its dispersion, stability and bond strengths in the polymer matrices of the carbon fiber reinforced composites. Wet layup process was applied to incorporate graphene nanocomposites into the dry carbon fibers to make composite panels following the curing cycle of the epoxy and hardener. The impacts of the functionalized graphene on the mechanical and thermal properties of carbon reinforced composite were investigated in detail by tensile test, differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy (SEM) analysis. It was observed that nanocomposites with 0.5 wt% silanized graphene exhibited maximum tensile strength and modulus of elasticity, indicating that 0.50 wt% silane functionalized graphene was the optimum nanofiller composition amongst the three different compositions investigated. The nanocomposites with 0.25 wt% and 0.50 wt% nanofillers showed improved ductility compared to the control sample. Based on the SEM studies on the crack zones, major morphological changes were observed after the salinization process. The interfacial interaction between epoxy and silane moiety of the graphene and reduction in the tendency to agglomerate could account for the improved properties of the nanocomposite observed here. Nanocomposites with silanized graphene showed overall higher glass transition temperature (Tg) and tensile strength than those with pristine graphene and control samples.