Characterization of Polypropylene Degradation Induced by Dielectric Barrier Discharge

Polypropylene (PP) is widely used as an insulating material in high-voltage applications, and methods capable of inducing measurable degradation-related property changes within a short period are useful for evaluating material responses. In this study, atmospheric- pressure dielectric barrier discharge (DBD) was applied to induce degradation-related changes in PP, and the electrical characteristics of the DBD were quantified using Q–V Lissajous curves. Oxidation and electrical properties were analyzed as functions of the applied voltage and treatment time, while surface morphology was evaluated after 100 min of treatment at different applied voltages. The discharge energy per cycle and average discharge power increased with applied voltage. The carbonyl index and dissipation factor generally increased with DBD treatment, whereas the volume resistivity decreased. The cumulative dissipated energy was estimated from the average discharge power and treatment time, and the degradation-related indicators showed overall changes with increasing cumulative energy; however, the data obtained at different applied voltages did not converge to a single common relationship. Surface irregularities and localized erosion became more pronounced at higher applied voltages. These results indicate that DBD treatment can induce measurable oxidation, electrical-property changes, and surface morphological changes in PP within a relatively short treatment period, although temporal equivalence between DBD treatment and conventional accelerated aging or long-term service aging remains to be established.