Dielectric characteristics on insulation oil due to the aging by electron beam irradiation

The electron beam is used to change a nature of polymers in these days. When the transformer oils is irradiated with electron beam in order to investigate the dielectric characteristics, there is a morphological change. It has already confirmed that the high dose of electron beam is caused to increase the magnitude of dielectric dissipation factor, tan/spl delta/, which can be estimated to the insulation of specimen. So, in this experiment, a low dose of electron beam such as 0.5[Mrad], 1[Mrad], 2[Mrad] is irradiated. Tan/spl delta/ is measured by Video Bridge 2150 in the applying voltage range 300[mV]/spl sim/1500[mV], in the temperature range 20[/spl deg/C]/spl sim/120[/spl deg/C], and in the frequency range 30[Hz]/spl sim/1/spl times/10/sup 5/[Hz]. In addition to investigating the electrical properties of each specimen, the physical properties of each specimen is analyzed by using the FT-IR spectrum and the /sup 1/H-NMR spectrum.