Stiffness prediction of graphene nanoplatelet/epoxy nanocomposites by a combined molecular dynamics–micromechanics method

In this research, by a combined molecular dynamics–micromechanics method the stiffness of graphene nanoplatelet/epoxy nanocomposites is predicted. It is assumed that graphene sheets are randomly oriented in the polymer matrix. First, the stiffness of a multilayered graphene nanoplatelet was achieved using the molecular dynamics (MD). Then, results obtained by the molecular dynamics were used by the Mori–Tanaka (MT) and the Halpin-Tsai (HT) micromechanics models to predict nanocomposite stiffness. These combined models are called the MD–MT and MD–HT models, respectively. The results obtained show that the MD–MT model is more compatible with the result of experiments at low filler contents (<0.25 wt.%) in comparison with the MD–HT model. While, the MD–HT model is more reliable at high filler contents (>0.25 wt.%). Mechanical properties of graphene nanoplatelet/epoxy nanocomposites with several contents of graphene nanoplatelet, i.e. 0.05, 0.1, 0.25, 0.5 and 1 wt.% were considered and the optimum graphene content was obtained.