Improved Thermal Conductivity at Low Temperatures in Epoxy Nanocomposites by Hexagonal Boron Nitride Aerogels

The development of large-scale superconducting magnets has motivated the current importance of manufacturing heat-dissipation polymers with high thermal conductivity at low temperatures. However, the extremely low thermal conductivity of epoxy resins from low temperature (0.03 W·m−1·K−1 at 77 K) to room temperature (0.21 W·m−·K−1 at 300 K) limits its application in superconducting fields. Here, we prepared hexagonal boron nitride nanoribbon (BNNRs) aerogels with high crystallinity by the precursor pyrolysis method, and then the epoxy was immersed into the BNNRs aerogels to obtain the EP/BNNRs aerogel composites. The microstructure of BNNRs aerogel were investigated by transmission electron microscope (TEM) and scanning electron microscope (SEM). The crystallinity and molecule structure were characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR). Under a low BNNRs aerogels filling content of 3.2 wt%, the thermal conductivity of the composites increased from 0.03 to 0.1 W·m−1·k−1 at 77 K, 0.21 to 0.38 W·m−1·k−1 at 300 K. In this work, we think the formation of thermal conduction path in BNNRs aerogels contributes to the improvement of thermal conductivity. Therefore, the as-designed material points the way to epoxy-based, thermally conductive for the applications of superconducting devices.