Designing Interfacial Reaction for BN@Si/Poly(phenylene oxide) Composites with Simultaneous Improved Thermal Conductivity and Dielectric Properties

With the soaring development of device integration, miniaturization, and high frequency, electric devices have put forward synchronous and urgent requirements for thermal management composites with insulation, high thermal conductivity (TC), and low dielectric properties. However, due to phonon scattering and interfacial polarization, these performance requirements are difficult to meet simultaneously. In this work, based on the principles of interfacial engineering, hexagonal boron nitride (BN) was functionalized with methylvinyldimethoxysilane (MVDMS), and poly(phenylene oxide) (PPO) was modified by methacrylic anhydride. Owing to the introduction of reactive groups, the reaction between modified BN (BN@Si) and modified PPO (MPPO) in the mixing process enhances the interfacial forces, improves filler dispersions, and helps to reduce phonon scattering and interfacial polarization. The resulting polymer composites have a high TC of 5.21 W/(m K) at 70 wt % filler loading, 20.7 times than that of the pure MPPO resin, low dielectric loss of 0.00252, and high thermal stability. It is shown that interfacial regulation is crucial for BN@Si/poly(phenylene oxide) composites. The obtained composites hold great potential as thermal management materials for 5G electronic devices.