Preparation of modified-boron nitride/epoxy resin composite with good thermal stability and thermal conductivity <i>via</i> directional freezing method

Abstract Improving thermal conductivity by directly blending filler with epoxy resin (ER) is often not ideal. The key is solving the dispersion of filler particle in matrix, which is crucial for establishing thermal conductive network. To achieve it, by utilizing the tannic acid (TA) modification and the alkali treatment of boron nitride (BN), OH-BN and BN@TA were obtained. Then, the chitosan-based framework was prepared via directional freezing method, where OH-BN or BN@TA acted as filler. Finally, the acquired framework was soaked in ER mixture, and the compound was cured to fabricate a new-type thermal conductive modified-BN/ER composite. The results indicated that the filler was uniformly dispersed, well adhered and directionally arranged within the framework, causing the formation of efficient thermal conductive pathway. The derived ER composite had good thermal stability with the decomposition temperature over 200 °C. Moreover, the thermal conductivity of ER composite exhibited maximum improvement rate of 210 % when the filling ratio of BN@TA was 30 wt%. The got ER composite could quickly transfer the heat, demonstrating its good heat dissipation capability. This study provided a new route to attain safe and efficient thermal conductive ER composite, which had great application prospect in the field of thermal management.