Effect of graphene nanoplatelets and montmorillonite nanoclay on mechanical and thermal properties of polymer nanocomposites and carbon fiber reinforced composites

Multifaceted effects of Graphene Nanoplatelets (GNP) and Montmorillonite Nanoclay (MMT) reinforcement on mechanical and thermal properties of DGEBA epoxy resin nanocomposites were investigated. Multi-step dispersion techniques involving ultrasonication, shear mixing and magnetic stirring were used to disperse nanoparticles. Impact on thermal properties was investigated via Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA), while mechanical properties were studied using Tensile and Three-point flexure tests. Graphene sheets were instrumental in increasing modulus and strength at a very low percentage whereas nanoclay was helpful in preserving thermal stability of the matrix thus creating a synergistic effect to reflect the reinforcing ability of both GNP and MMT in mechanical and thermal aspects respectively. X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) studies showed mixed intercalation and exfoliation of nanoparticles with increased inter-planar spacing and decrease in intensity of crystal peaks. SEM micrographs of failed samples revealed failure mechanisms and the aid of GNP to resist failure. To further investigate the effect of binary nano-reinforcement, hybrid Carbon Fiber Reinforced Polymer (CFRP) samples were fabricated and tested for mechanical properties via Tensile and Flexural tests. The mode of failure was analyzed by SEM imaging. It was confirmed that GNP reinforcement helped in increasing the mechanical properties of material.