Evaluation of dielectric films for aerospace and space power wiring insulation

Three high-performance dielectric films, perfluoroalkoxy (PFA), poly-p-xylene (PPX), and polybenzimidazole (PBI), were characterized to explore their possible use as a replacement for Kapton in high-voltage wiring insulation. The dielectric properties of PFA and PPX, including permittivity and dissipation factor, were obtained in a frequency range of 50 Hz to 100 kHz and at temperatures up to 200°C, and the AC dielectric strength was determined at temperatures up to 250°C. For PBI, the dielectric properties were obtained at temperatures up to 250°C and the dielectric strength at temperatures up to 300°C. The experimental results are compared with those for Kapton. The results indicate that PBI film can withstand temperatures up to 300°C and maintain all its electrical properties at elevated temperatures. PFA and PPX dielectric films, like Kapton, are capable of maintaining their electrical properties, with minimal degradation, at temperatures up to 200°C