Construction of three-dimensional network using boron nitride microspheres and the thermal conductivity/stability of epoxy resin composites

Efficient heat dissipation has become the focus of electronic packaging materials, constructing three-dimensional thermally conductive filler networks to prepare composites can realize efficient heat transfer. However, there are few studies comparing the effects of different ways of constructing three-dimensional networks on the thermal conductivity enhancement of polymers. In this study, BNMS self-assembled from BNNSs was used as a thermally conductive filler, and the three-dimensional skeleton was constructed by both the powder mixing compression pressing method and the ice template method, and scanned to analyze the morphological and structural characteristics. At the same time, the epoxy composites were prepared, and the advantages and disadvantages of the thermal conductivity of the composites prepared in different ways were analyzed by combining the SEM structures. In the powder hybrid compression pressing method, the in-plane and through-plane thermal conductivity of the epoxy composites with the BNMS additive amount of 53.92 wt% reached 10.961 W·m−1·K−1 and 9.955 W·m−1·K−1, respectively, which was increased by 58 and 52 times. The thermal stability has been improved significantly that the T60 was in creased by 60.89 °C compared to pure epoxy. Using the ice template method with 7.67 wt% of BNMS addition, the through-plane thermal conductivity of the epoxy composites reaches 0.977 W·m−1·K−1, which is an improvement of 428.1 % compared with pure EP. In addition, both composites maintain low dielectric constants and dielectric losses. It is instructive for the preparation method of subsequent construction of three-dimensional thermally conductive filler networks.