This study performs the thermal aging of chlorosulfonated polyethylene (CSPE) for 807.36 and 1,614.48 hours at 110℃, which is equivalent to 40 and 80 years of aging at 50℃ in nuclear power plants, respectively. Flat-type CSPEs were soaked in seawater for five days and then dried for five days at room temperature. Furthermore, the soaked CSPEs were cleaned for 5 days with fresh water and dried for 1,100 days at room temperature. Through this process, the log IV of the CSPEs decreases, whereas the dissipation factor of the CSPEs increases as thermally accelerated aged years increase at the measured frequency. Although the phase degree of the response voltage versus excitation voltage of the CSPEs increases, that of the response current versus excitation voltage decreases with the thermally accelerated aging. The thermal conductivity of the CSPEs increases slightly, but the thermal diffusivity does not vary with the thermally accelerated aged year increase. The displacement of the compressive strength of the CSPEs decreases gradually as the thermally accelerated aged years increase.

The accelerated thermal aging of a CSPE were carried out for 0, 80.82, 161.63 days at 100℃, which are equal to 0, 40 and 80 years of aging at 50℃, respectively. The volume electrical resistivities of the seawater and freshwater flooding were measured through 3-terminal circuit diagram. The volume electrical resistivities of the 0y, 40y and 80y were 2.454×1013∼1.377×1014Ω?cm, 1.121×1013∼7.529×1013Ω?cm and 1.284×1013∼8.974×1013Ω?cm at room temperature, respectively. The dielectric constant of the 0y, 40y and 80y were 2.922∼3.431, 2.613∼3.285 and 2.921∼3.332 at room temperature, respectively. It is certain that the ionic (Na+, Cl-, Mg2+, SO4 2-, Ca2+, K+) conduction current was formed by the salinity of the seawater. The volume electrical resistivity of the cleaned CSPE via freshwater trends slightly upward with the number of dried days at room temperature. As a result, the CH2 component of thermally accelerated aged CSPE decreased after seawater and freshwater flooding for 5 days respectively, whereas the atoms such as Cl, O, Pb, Al, Si, Sb, S related with the conducting ion (Na+, Cl-, Mg2+, SO4 2-, Ca2+, K+) component increased relatively.