Effect of hexagonal boron nitride on the thermal and dielectric properties of polyphenylene ether resin for high-frequency copper clad laminates

Highlights: • Polyphenylene ether resin filled with hBN or hBN@SiO₂ were used as an insulation layer of copper clad laminates. • The as-obtained copper clad laminates exhibited a high advantage in thermal and dielectric properties. • A modified model for the thermal conductivity was proposed taking into consideration of the SiO₂ effect of on hBN. -- Abstract: As the base material of the printed circuit boards (PCBs), copper clad laminates (CCLs) with high thermal conductivity, low dielectric loss and high peel strength have been greatly desired especially for the upcoming 5G age. In this study, hexagonal boron nitride (hBN) was firstly introduced into the polymer insulating filler (Polyphenylene ether resin, PPER) of copper clad laminates for high frequency applications. The as-obtained CCLs exhibited a high thermal conductivity up to 1W/m·K and a low dielectric loss of ~4×10⁻³. Meanwhile, the interface tailoring of hBN was also tried by SiO₂ coating, which enhanced the peel strength to a maximum value of 1.1N/mm, but changed the thermal conductivity behavior of the CCLs from the Agari's linear model to the modified quadratic model due to the interfacial thermal resistance effect of SiO₂ coating on hBN. Moreover, the flexural strength and water absorption were also tested. The results revealed that, comparing with the related composite materials reported in literature and commercial products, the CCLs obtained in this paper have outstanding advantages in thermal and dielectric properties, validating the high potential of the present CCLs for use in high frequency PCBs.