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Enhanced thermal conductivity in epoxy nanocomposites with hybrid boron nitride nanotubes and nanosheets



This paper is an effort to solve the issue related to the electrically insulating polymer composites for thermal interface materials applications. A novel strategy is designed to achieve both enhanced thermal conductivity and high electrical insulation of epoxy composites by combining one-dimensional boron nitride nanotubes (BNNTs) and two-dimensional boron nitride nanosheets (BNNSs). A noncovalent functionalization approach is used to functionalize and solubilize hybrid BNNTs/BNNSs fillers by 1-pyrenebutyric acid (PBA) molecules. The PBA-functionalized BNNTs/BNNSs exhibit good dispersion and high compatibility with epoxy matrix. The epoxy composites with PBA-functionalized BNNTs/BNNSs hybrid fillers yield a thermal conductivity of 0.47 W m−1 K−1 and an electrical resistivity of 9.3 × 1016 Ω cm at 2 wt% filler loading, which outperform the epoxy composites with individual PBA-functionalized BNNTs or BNNSs fillers.