Synergistic effect of h-BN on thermal conductivity of polymer composites

Abstract

The conductivity characteristics of polymers and polymer composites have become more significant recently. Good heat dissipation is required in many applications, such as circuit boards and heat exchangers, so it is essential to develop the thermal conductivity characteristics of the materials. The micro-fillers have been replaced with nano or hybrid fillers to increase the low thermal conductivity of the polymer. Hexagonal boron nitride (h-BN) and multi-walled carbon nanotubes (MW-CNT), both of which have good conductivity properties, are two popular filling materials. The presence of hydroxyl and amino active groups at the corners of the hexagonal structure of BN improves the thermal conductivity properties of the polymer composite. In addition, it shows high thermal conductivity behavior in polymer composite structures with BN and MW-CNT. It is essential to demonstrate the effects of the volume fraction of additives on the thermal properties of composites with various approaches. In this study, the thermal conductivity behaviors of h-BN/high-density polyethylene and h-BN/MW-CNT/high-density polyethylene composites are demonstrated using the theoretical Bruggeman model, which is based on the assumption that there are constant infinitesimal changes in the material so that there is an interaction between particles. The coefficient of determination (R²) between the thermal conductivity values of the composites and the predictions of the Bruggeman theoretical model is greater than 0.98. This way, the synergetic effect of h-BN and MW-CNT/h-BN additives on thermal conductivity has been theoretically proven.