抄録
Polyparabanic acid (PPA) is one of the excellent heat-resistive insulating materials. The infiuence of the chemical structure on the breakdown of PPA has been investigated. The breakdown strength was measured with dc and pulse voltages. The breakdown strength in both cases decreases with temperature in the range of 120-180°C. The results indicate the significant dependence of the breakdown strength on the chemical structure of PPA. Thermal breakdown has been proposed as the mechanism responsible for the breakdown. The results have been discussed quantitatively by taking the electric conduction mechanism into consideration.
