Mussel-inspired modification of boron nitride for natural rubber composites with high thermal conductivity and low dielectric constant

Owing to the development of modern micro-electronic devices, polymer composites with high thermal conductivity and low dielectric constant have become increasingly important. Herein, a combination of covalent and non-covalent modification was used to functionalize boron nitride (BN) platelets via first deposition with poly(dopamine) (PDA) followed by grafting with γ-methacryloxypropyl trimethoxy silane (KH570) (denoted as BN-PDA-KH570). The as-prepared BN-PDA-KH570 platelets were incorporated into the natural rubber (NR) matrix to prepare thermal conductive composites. After modification with PDA-KH570, the BN platelets were uniformly dispersed into the NR matrix, which is beneficial for improving the thermal conductivity of NR. The interfacial thermal resistance of the composites was also reduced due to the stronger interfacial interaction via vulcanization of NR with double bonds in KH570. Thus, the NR composites filled with 30 vol% BN-PDA-KH570 platelets exhibited a relatively high thermal conductivity of 0.39 W/mK, which is about 1.5 times and 4 times of 30 vol% BN/NR composite (0.26 W/mK) and pure NR (0.10 W/mK), respectively. In addition, the BN-PDA-KH570/NR composites exhibited a low dielectric constant (3.51 at 100 Hz) and a low dielectric loss tangent (0.25 at 100 Hz), which holds promising applications as thermal management materials for electronic devices.