Influence of Surface Fluorination Treatment on Properties of Polypropylene Film

Biaxially-oriented polypropylene (BOPP) film is currently an indispensable material for pulse capacitor production. The breakdown field strength and leakage current are the key indicators of the metallized film, which affect the energy storage density and voltage holding performance of the capacitor. In this paper, BOPP film is subjected to surface treatment with different fluorination time and different fluoride concentration. The changes in material properties, such as the chemical bond, element content and crystallinity of the film after the fluorination treatment, are studied and analyzed. Then, the electrical properties, such as breakdown field strength, dielectric loss and leakage current of the film after the fluorination treatment, are studied. It is found that the fluorination treatment can increase the breakdown field strength of the dielectric film by 8.7%, increasing the energy storage density by 18%. It has little effect on the loss and leakage current of the film.