Ako Parsa - MSc. student of mechanical department, University of Tehran
Mahmoud MosaviMashhadi - Professor of mechanical engineering, University of Tehran

Experimental data suggests that well dispersed nanoparticles within a polymer matrix induce a significant interphase zone of altered polymer mobility surrounding each nanoparticle, which can lead to a third phase inside of the composite. To investigate this concept and the nature of the interphase, a threedimensional finite element model is developed to study the impact of interphase zone on the overall properties of the composite. In this paper the influence of interphase properties on overall mechanical properties of carbon nanotube reinforced polymer is investigated by using a 3-phase RVE1. The effective material properties of RVE are obtained by substituting the FEM results of RVE under certain loads into corresponding elasticity equations. First, the influence of thickness and mechanical properties of interphase layer on effective material properties of RVE is studied. To compare the result of a unite cell containing several CNTs with experimental data, the mechanical properties ofinterphase layer is defined based on a viscoelastic approach. Results show that interphase layer has significant influence on overall mechanical properties of nanocomposites and considering this phase in simulations will cause to predict their properties more accurately.

carbon nanotube/polymer interface,interphase properties, representative volume element