Investigating effect of CNT agglomeration in CNT/polymer nanocomposites using multiscale finite element method

A multiscale finite element model based on molecular structural mechanics is developed in this paper to investigate the effect of CNT agglomeration on the bulk elastic properties of CNT-reinforced polymer nanocomposites. In this model, both the CNTs and the interphases (among the CNTs as well as between the CNTs and the matrix) are introduced as discrete structures into a representative volume element (RVE) of the nanocomposite. The surrounding polymer in the RVE is considered a continuum medium; however, the parameters for the non-bonded interactions between the CNT and the polymer are calculated based on the atomic structure of the polymer, and the nodal density of the finite element mesh is kept to be the same as the atomic density of the polymer. Nanocomposites having different combinations of single-walled CNT and the polymer at different volume fractions of CNT are studied. The model is first applied to nanocomposites reinforced with single CNTs and validated using published results. The model is then used to investigate the effects of CNT agglomeration on the effective elastic properties of nanocomposites consisting of both long and short CNTs.