Investigation of the dielectric and thermal conductive properties of core-shell structured HGM@hBN/PTFE composites

Porous polymer materials have been widely used for the preparation of low dielectric constant materials, but they also suffer from high moisture absorption and decreased thermal conductivity. In this study, core-shell structured hexagonal boron nitride coated hollow glass microsphere (HGM@hBN) particles were prepared using an electrostatic-assembly process and incorporated into poly(tetrafluoroethylene) (PTFE). The composites exhibited decreased dielectric constants due to the implantation of air, which is mainly encapsulated in HGM. The hBN layer on the surface of HGM effectively enhanced composite thermal conductivity due to its special coreshell form. The 30 vol% HGM@hBN/PTFE composites had a low dielectric constant of 1.68, low moisture absorption of 0.11%, and thermal conductivity (0.276 W/mK) was improved by 43% compared with that of 30 vol % HGM/PTFE composites. This study provides a facile and cost-effective strategy for fabricating polymer composites with low dielectric constant, low moisture absorption and no deteriorated thermal conductivity simultaneously.