Preparation and properties of three‐dimensional boron nitride submicron tube/epoxy resin composites with high thermal conductivity

Abstract Heat dissipation of electronic devices was an urgent problem to be addressed. In this paper, magnesium borate whiskers were used as the template for the preparation of the boron nitride submicron tube (BNST). Then the polymer‐free supported three‐dimensional boron nitride submicron tube skeleton was prepared by sacrificing the material ammonia bicarbonate. Finally, high thermal conductivity boron nitride submicron tube/epoxy resin (BNST/EP) composites were prepared by infiltrating technique. The phase, chemical composition, microstructure, thermal conductivity, and thermal stability of the samples were studied by X‐ray diffraction, scanning electron microscopy, and other characterization methods. The results show that BNST has an average diameter was 2 um and the tube length was 5–20 um. The surface of BNST was loaded with a large number of boron nitride nanosheets. The in‐plane thermal conductivity of the BNST/EP composite was improved by the three‐dimensional BNST skeleton. When the BNST was 39.28 wt%, the in‐plane thermal conductivity reached 1.632 W/(m K). Compared with pure EP, the in‐plane thermal conductivity was increased by 782.2%. BNST played a good physical barrier effect on the matrix, so the thermal stability of the composite was greatly improved. This strategy will open up a new path to prepare heat dissipation materials.