DC Breakdown Characteristics of Biodegradable Polyethylene Films

A study has been carried out on DC breakdown characteristics of biodegradable polyethylene (BDPE) film, with high-density polyethylene (HDPE) film as a reference. The patterns of breakdown craters were obtained by a monocular zoom microscope. These patterns revealed that the shape of breakdown crater is almost identical to the type of electrodes as well as the location of samples. Meanwhile, the obtained results were calculated by a mathematical statistic method. From the test results, it can be observed that the breakdown crater is smaller with the film at the plane-electrode side than that at the sphere/needle-electrode side, and that at the middle of gap is the biggest. The effective area under positive bias voltage is much smaller than that under negative bias voltage. Under positive bias voltage, the breakdown area of BDPE is smaller than that of HDPE, while under negative bias voltage, the difference is insignificant between BDPE and HDPE.