Investigation of the Interphase Effects on the Mechanical Behavior of Carbon Nanotube Polymer Composites by Multiscale Modeling

In this article, a multiscale modeling procedure is implemented to study the effect of interphase on the Young's modulus of CNT/polymer composites. For this purpose, a three-phase RVE is introduced which consists of three components, i.e., a carbon nanotube, an interphase layer, and an outer polymer matrix. The nanotube is modeled at the atomistic scale using molecular structural mechanics. Moreover, three-dimensional elements are employed to model the interphase layer and polymer matrix. The nanotube and polymer matrix are assumed to be bonded by van der Waals interactions based on the Lennard-Jones potential at the interface. Using this Molecular Structural Mechanics/Finite Element multiscale model, we investigate the macroscopic material properties of nanocomposite with and without considering the interphase and compare the results with molecular dynamics (MD) simulations. It is shown that there is a noticeable deviation from MD results with two-phase model. Meanwhile, the three-phase modeling shows that by considering the effect of the interphase, the elastic constants of these nanocomposites could be calculated the same as the MD results with maximum deviation of 1.8% and negligible computational cost in comparison with the MD simulation. Hence, considering the interphase layer in modeling the CNT-based nanocomposites is necessary and cannot be ignored. (C) 2010 Wiley Periodicals, Inc. I Appl Polym Sci 117: 361-367, 2010