Abstract
In this study, we measured the leakage current at 30~80oC and 90~170oC under a voltage of 200~980 V applied to samples (ordinary temperature) and polyamide film specimens degraded at 170°C for 20 minute respectively. After the specimen was degraded at 130°C and 50°C, a voltage of 200 to 800 V was applied for 10 to 60 minutes. The measurement of the leakage current resulted in the following conclusions. In the case of using Al and Cu as the main electrode, it was confirmed that the leakage current also increased in high temperatures as the voltage increased. Regardless of the type of main electrode, when the temperature was constant at 130°C and 50°C, the leakage current increased as the voltage increased, and gradually decreased with time. As a result of the FTIR measurement, the main absorption of the infrared absorption spectrum was C=O at about 1650 cm−1 and N-H diagonal vibration occurred at around 1550 cm−1. There was no change in the material, so no effect of temperature was observed. By the results of SEM measurements, as the temperature of degradation increases, cracks in the specimen disappear. This may be because the amide bond (-CO-NH-) is absorbed by the material.
Keywords: infrared absorption spectrum;temperature of degradation