A molecular dynamics study on mechanical properties of polymer nanocomposites reinforced by two-dimensional nanosheets

Molecular dynamics (MD) simulations have been performed to determine the reinforcing role of two-dimensional (2D) nanosheets on Young's and shear moduli of nanosheet-strengthened polylactic acid (PLA). Various volume fractions of nanosheets in addition to different kinds of nanosheets, that is, graphene (GR), silicon carbide nanosheet (SiCNS), and boron-nitride nanosheet (BNNS), are regarded as affecting parameters on the mechanical response. Uniaxial tensile and shear tests are conducted and related stress-strain diagrams are achieved to be used for exploring mechanical properties. It is found that the incorporation of 2D nanosheets into PLA has a noticeable impact on the mechanical behavior of the polymer. In a desired percentage of volume fraction (${\rm v}_{\rm f}$vf), GR and SiCNS have performed the greatest and least roles in augmenting the mechanical properties of PLA nanocomposites, respectively. Compared to those, the reinforcing effect of the BNNS comes in between. Also, the results show that there is a growing trend in longitudinal and transverse Young's moduli (${\rm E}_{\rm x}$Ex and ${\rm E}_{\rm y}$Ey) and the XY-plane shear modulus (${\rm G}_{{\rm xy}}$Gxy) of nanocomposites as the ${\rm v}_{\rm f}$vf of nanosheets increases.