Polyphenylene oxide/SiO2 composites: Towards ultra-low dielectric loss and high thermal conductivity of microwave substrates

Abstract

With the rapid development of electronic information industry has raised the requirements for the performance of electronic components. Therefore, it is essential to research dielectric substrate materials with excellent dielectric properties and good thermal conductivity at high frequencies. This study introduced vinyl trimethoxysilane (VTMS) surface-functionalized silicon dioxide (SiO2) into the polyphenylene oxide/styrene–butadiene–styrene/triallyl isocyanurate (PST) composite resin to prepare PST/V-SiO2 composite. The microwave composite substrates for high-speed signal propagation were prepared through a process involving scraping coating and hot pressing. The study investigated the impact of varying amounts of V-SiO2 on the dielectric property, thermal stability, and thermal conductivity of the composites. The microwave composite substrates exhibit excellent dielectric properties and good thermal conductivity. When the V-SiO2 content is 80 wt%, the dielectric loss is 1.8 × 10-3 with a low dielectric constant (≤3.23@10 GHz). Furthermore, the PST/V-SiO2 composite displays higher thermal conductivity (0.735 W/(m·K)) and low moisture absorption. This research provides a novel strategy to develop microwave composite substrates with low dielectric loss and high thermal conductivity.