Stretchable and High Thermally Conductive Boron Nitride Nanosheet/Poly(Thioctic Acid) Nacre-Like Nanocomposites for Thermal Management Applications

The development of high-power density electronic devices and electrical equipment has put forward the higher thermal conductivity requirements of electrical insulating materials. Nacre-like dielectric polymer nanocomposites can have high thermal conductivity and electrical insulation because of the highly oriented packing arrangement. However, these materials also have poor stretchability. Here, we report nacrelike boron nitride nanosheets/poly(thioctic acid)(BNNS/PTA) nanocomposites prepared by vacuum-assisted filtration. It was found that the BNNS/PTA nanocomposites can exhibit a high inplane thermal conductivity of $21.2 \mathrm{~W}^* \mathrm{~m}^{-1 *} \mathrm{~K}^{-1}$ and an elongation of 32 % at 60 wt % BNNS filler content. We attributed this excellent thermal and mechanical property to the in-plane alignment of surface-modified BNNSs and the high flexibility of PTA. In addition, the nanocomposites can reduce the peak operating temperature of 5 G base station chips by $10^{\circ} \mathrm{C}$, showing a wide application prospect in the heat dissipation of high-power electronic devices.