Anisotropic thermal conductivity of aligned GNPs/polymer composites: a finite element approach

In this article, we propose a 3D FEM model to analyze the anisotropic thermal behavior of oriented GNPs/polymer composites. The model considers the effect of microstructural characteristics such as the shape and aspect ratio of filler, interfacial thermal resistance, volume fraction, dispersion state and orientation of GNPs dispersion to simulate a steady state heat flow in the composite. In the simulation model, the composite is treated as a cubic unit cell and GNPs are modeled as oblate spheroid with a long axis diameter of 1 mu m and the aspect ratio is in the range of 0.01 to 0.05. The oblate spheroids align in the cubic to represent the microstructure of the oriented GNPs/polymer composites. By varying the number of the GNPs in the representative unit cell, the volume fractions of fillers are determined. The simulation results show that the parallel thermal conductivity (//) increase in a nonlinear trend and the perpendicular thermal conductivity (perpendicular to) is slightly linear increasing. Compared with experimental results, the trends predicted by the finite element models are consistent.