Quantifying nanodiamonds assisted exfoliation of graphene and its effect on toughening behaviour of composite structure

Abstract Graphene (Gr) is one of the most preferred reinforcement for polymer matrix, due to its large surface area. However, poor dispersion, due to stacking of Gr sheets, restricts their potential as reinforcement. In the present study, exfoliation of multi-layered graphene sheets is achieved in the presence of nanodiamond (ND), using ultrasonication. High-resolution electron micrographs clearly reveal the role played by ND in hindering restacking of graphene. SPM imaging further quantified exfoliation by measuring the thickness for different combinations of Gr:ND. Improved exfoliation of Gr increases both tensile strength and strain by ~71% and ~113%, respectively, for >0.5 wt% Gr content. Fracture toughness is improved by ~150% with Gr, and an additional 44% with ND decorated Gr. Numerical analysis further confirms the effect of ND assisted exfoliation of Gr in toughening behavior of the composite, which can be explained in terms of improved total interface area, helping in better load transfer.