Improved anti-aging performances based on doping of organic additives of PP films for capacitors

During the operation of the power capacitors, thermal aging will be caused by the coupling effects of high ambient temperature and dielectric loss. This complicated aging process leads to the dielectric performance degradation and eventually cause the life end of capacitors. Therefore, there is an urgent need to improve the anti-aging properties of polypropylene films. Different types of organic additives were added to polypropylene, and film samples were prepared by melt blending and hot pressing. The samples were subjected to heat aging treatment for 0, 240 and 480 hours at temperature of 120 °C. FTIR and DSC were used to characterize the microstructures and thermal properties of the samples. The Weibull distribution was used to analyze the DC breakdown field strength. After thermal aging treatment, the molecular chains of the film are broken, and internal small molecules are generated. The modified film has a higher breakdown strength than pure PP and shows excellent anti-aging properties. The modification method proposed in this paper can help improve the long-term operating characteristics of the capacitors.