Charge Transport and DC Breakdown in Polymer Based Micro/Nano-Composite with Different Filler Orientations

Hexagonal boron nitride (h-BN) has been extensively considered as filler in order to improve thermal conductivity of the polymeric materials. As a 2D material, the orientation of h-BN will affect the insulation property of the polymer. Therefore, it is important to understand the influence of filler orientations on the insulation performance of the polymer. In this work, the orientations of the h-BN fillers were assumed to be parallel, perpendicular to the normal vector of sample surface or randomly distributed in the matrix, and the charge transport behavior and DC breakdown strength in different samples were discussed. The bipolar charge transport (BCT) model has been adopted to estimate the charge transport and the breakdown behavior in the micro/nano-composite with the purpose of better understanding the orientation effect. The obtained results indicated that the density of trapped charge was the largest in the sample with filler distributing perpendicularly compared with others and the breakdown of the polymer with vertical filler orientation could occur first. It is suggested that the material with the parallel orientation of the filler is expected to improve the insulation performance of the polymer.