Improved Thermal Conductivity of Polymer Composites by Noncovalent Modification of Boron Nitride via Tannic Acid Chemistry

With the advent of the 5G era, hexagonal boron nitride (BN) platelets are ideal fillers to incorporate into polymers for preparing thermally conductive composites, which are applied in relieving the heat dissipation in electronic devices. In this study, we report a green, low cost, and high-efficient method to improve the thermal conductivity (λ) of carboxylated acrylonitrile-butadiene rubber (XNBR) composites via noncovalent modification of boron nitride (BN) via tannic acid (TA) chemistry. The noncovalent TA decorating on the surface of BN without deteriorating the surface structure of BN platelets ensures the high intrinsic λ of BN. Additionally, TA enhances the interfacial compatibility between the filler and matrix, as well as the formation of a thermally conductive path in the composites. The maximum through-plane λ is obtained by 30 vol % BN-TA-XNBR composite as 0.42 W/mK, which is 260% of that for pure XNBR (0.16 W/mK). The excellent dielectric properties of BN-TA-XNBR composites also indicates that the BN-TA-XNBR composites can meet the requirements of high capacitance and low energy loss of electronic devices. In brief, the TA chemistry provides potential applications in large scale production of thermally conductive composites in industries, as well as paves the way for advanced applications in next-generation miniaturization and integration of electronic devices.