Superior high-temperature dielectric properties of dicyclopentadiene resin

Complex permittivity (ϵ_r′ and ϵ_r″) and conductivity were measured in a wide temperature range for dicyclopentadiene (DCP) resin and epoxy resin, which show glass transition at a similar temperature around 150 °C. Furthermore, space charge distributions remaining in the two resins that had been polarized in the same wide temperature range were measured at room temperature. As a result, it was found that ϵ_r′, ϵ_r″, and conductivity are much lower in DCP resin than in epoxy resin at almost all the temperatures and frequencies. A further analysis using complex electric modulus, which is the inverse of the complex permittivity, indicates that charge transport is much more difficult in DCP resin. Furthermore, while similar small amounts of homocharges appear in DCP resin at any polarization temperatures, a significant accumulation of heterocharges, most likely due to ions, is induced in epoxy resin in the vicinity of the cathode/sample interface at polarization temperatures above the glass transition temperature. These results indicate that DCP resin possesses superior stable dielectric behavior, especially at high temperatures.