Enhancement of thermal conductivity of h-BN/polymer thermal sheets by combining boron nitride nanotubes (BNNTs)

D. Seo, H. Jeong, J. Kim, Y. Oh, J. Kim
Naieel Technology,
Korea

Keywords: h-BN, Boron nitride nanotubes, epoxy composites, thermal conductivity, heat dissipation, thermal interface materials

Summary:

In this study, we used boron nitride nanotubes (BNNT) to enhance the thermal conductivity of the h-BN/polymer composite sheets used as a thermal dissipating material for the electronic devices. BNNT used in this investigation was synthesized using thermal annealing of nano-boron precursor under the N2 environment. By combining a small amount of 1-D BNNT with 2-D h-BN in polymer, we observed that the thermal conductivity could be increased as high as 2 times by presumably constructing the BNNT thermal conducting channels between h-BN particles inside the polymer resin. This is the first experimental observation that BNNT enhances the thermal conducting property of the h-BN dispersed polymers. We evaluated the thermal conductivity and electric breakdown voltages of the BNNT/h-BN/epoxy and silicon composites. The prepared BNNT combined polymer composites present the thermal conductivities of 3.4~3.8 W/mK with 0.5 wt% of BNNT compared to h-BN dispersed composites of 1.27~1.8 W/mK depending on the resin densities, while the breakdown voltage was higher than 26 kV/mm. Thermal conductivity was achieved 10 W/mK for the h-BN and aluminum nitride (AlN) combined filler with BNNT, when the density was increased to 2 g/cm3. Consequently, BNNT may offer an efficient way of alleviating the heat problem encountered in various IT devices such as smartphones, wearable sensors/robots, LED, and electric vehicles, etc.