Highly Ordered BN<sub>⊥</sub>–BN<sub>⊥</sub> Stacking Structure for Improved Thermally Conductive Polymer Composites
B. Ghosh, Fang Xu, David M. Grant, Paolo Giangrande, Chris Gerada, Michael W. George, Xianghui Hou
Abstract
Abstract The substantial heat generation in modern electronic devices is one of the major issues requiring efficient thermal management. This work demonstrates a novel concept for the design of thermally conducting networks inside a polymer matrix for the development of highly thermally conductive composites. Highly ordered hexagonal boron nitride (hBN) structures are obtained utilizing a freeze‐casting method. These structures are then thermally sintered to get a continuous network of BN ⊥ –BN ⊥ of high thermal conductivity in which a polymer matrix can be impregnated, enabling a directional and thermally conducting composite. The highest achieved thermal conductivity ( K ) is 4.38 W m −1 K −1 with a BN loading of 32 vol%. The effect of sintering temperatures on the K of the composite is investigated to optimize connectivity and thermal pathways while maintaining an open structure (porosity ≈ 2.7%). The composites also maintain good electrical insulation (volume resistivity ≈ 10 14 Ω cm). This new approach of thermally sintering BN ⊥ –BN ⊥ aligned structures opens up a new avenue for the design and preparation of filler alignment in polymer‐based composites for improving the thermal conductivity while maintaining high electrical resistance, which is a topic of interest in electronic packaging and power electronics applications.