Molecular Mechanism of h-BN Enhancing the Thermal Conductivity of PEEK

Abstract As electronic devices rapidly evolve towards higher power density and integration, the importance of efficient thermal management grows significantly. In the context of nano-reinforced thermoplastic composites, establishing effective thermal path through the filler network is crucial. In this study, by optimizing the ratios of two sizes of hexagonal boron nitride (h-BN) nanosheets in the poly (ether ether ketone) (PEEK) matrix, a significant enhancement of the thermal conductivity of PEEK/h-BN composites was achieved. The thermal conductivity of a PEEK/h-BN composite containing a 3:7 weight ratio of the two sizes of h-BN(with 15wt% overall h-BN content) achieved the highest thermal conductivity of 0.87 W/mK due to the formation of more complete thermal paths. Additionally, based on the structural distribution of boron nitride nanosheets (BNNSs) observed in scanning electron microscopy (SEM), the influence of heat transfer direction along single-layer BNNSs, as well as the interlayer relative displacement and torsional angle of bilayer BNNSs, on the thermal conductivity of BNNSs/PEEK composites was investigated through molecular dynamics simulations. The results show that when heat flow is transmitted along the armchair direction of BNNSs, the BNNSs/PEEK composites exhibit higher thermal conductivity. Furthermore, by regulating the microstructure of BNNSs, the interface scattering in BNNSs/PEEK composites can be effectively reduced, and the interfacial coupling of BNNSs/PEEK composites can be improved, leading to an enhancement in thermal conductivity. This study provides experimental data and theoretical support for the further development of high-performance thermal management materials.