Investigation of dielectric and thermal conductive properties of epoxy resins modified by core-shell structured PS@SiO₂

In this study, the core-shell structured polystyrene@SiO₂ (PS@SiO₂) microspheres were successfully synthesized by tetraethylorthosilicate (TEOS) hydrolysis method. The synthesized PS@SiO₂ microspheres were subsequently characterized by FTIR spectroscopy, XRD, SEM, and TEM respectively. The results indicated that the particle size of PS@SiO₂ microspheres is about 2 μm, and the PS microsphere is uniformly coated by amorphous SiO₂ shell. PS@SiO₂/cyanate ester (CE)/epoxy resin (ER) composite films were prepared with PS@SiO₂ microspheres as fillers and morphology of the films was inspected by AFM. The images showed that the PS@SiO₂ microspheres were well-distributed in epoxy matrix. Thermal conductivity of PS@SiO₂/CE/ER composite increases 131% by adding 1.0 wt% of PS@SiO₂ microspheres. The volume resistivity of composites decreased with increasing of the loading of PS@SiO₂ fillers and still keeping an excellent insulating performance. In addition, the dielectric constant as well as the dielectric loss of composites increased with the increased the content of PS@SiO₂ microspheres.