Electrical properties of thermoplastic polyimide

Conduction process of thermoplastic polyimide has been examined. The as-received sample shows a current with a peak at /spl sim/230/spl deg/C even when any poling bias has been applied. However, this spontaneous current disappears if the measurement is repeated. Conduction current decreases if the sample was heat-treated. It is considered that impurities such as K and Na remaining in the sample are responsible for the current peak or the spontaneous current.