Comparison of dielectric properties among polydicyclopentadiene resin, epoxy resin and their composites with microsized SiO2 fillers

Complex permittivity spectra of polydicyclopentadiene resin and epoxy resin, and their composites with SiO₂ microfiller were obtained in a wide temperature and frequency range. Both ε_r\´ and ε_r" at high temperatures above their glass transition temperatures (T_g\´s) are much lower in polydicyclopentadiene resin than in epoxy resin, even though the two T_g\´s are almost the same. Furthermore, analysis using electric modulus has revealed that addition of the microfiller in epoxy resin suppresses dipolar orientation and charge transport. However, both the dipolar orientation and charge transport seem to be difficult in polydicyclopentadien resin and its composite compared to epoxy resin and its composite.