Experimental and multiscale quantum mechanics modeling of the mechanical properties of PVC/graphene nanocomposite

In current work, we developed mechanical properties of PVC (polyvinyl chloride)/graphene nanocomposite theoretically and experimentally. In our theoretical model, a multi-scale finite element model was used to predict Young's modulus of the stated nanocomposite. The molecular structure of pristine graphene was treated using the density functional theory (DFT) method. By assuming graphene as a space-frame structure that preserves the discrete nature of graphene, they were modeled by the use of three-dimensional elastic beam elements for the Carbon-Carbon covalent bonds and point mass elements for the atoms. Then interfacial van der Waals interaction that exists between PVC and graphene was modeled using the general form of Lennard-Jones potential and simulated by a nonlinear truss rod model. The Lennard-Jones parameters and van der Waals forces were determined versus separation distance for the stated nonlinear truss rod via the DFT method. Finally, we prepared PVC/graphene samples with different weight percentages of graphene nanoplatelets experimentally using the melt-mixing procedure. Our computational modeling demonstrated that the magnitudes of Young's modulus PVC/graphene were close to the experimentally obtained results until 1 wt% with an average difference of about 25%. Finally, we justified the obtained mechanical results by investigating the morphology of experimental samples using Transmission electron microscopy (TEM) and Scanning Electron Microscopy (SEM) images.