Molecular simulation and experimental investigation of enhanced thermal and dielectric properties in mica-filled polyimide films

Aromatic polyimide (PI) is widely used in aerospace, microelectronics, and transformer insulation due to its excellent performance and design flexibility. With the rapid development of the military industry, the insulation layer of Tesla transformer windings demands low dielectric, high heat resistance, high breakdown strength, and aging resistance. This paper studies the performance of polyimide insulation film based on theoretical calculation and experimental methods. We used molecular simulation technology and density functional theory (DFT) to study the microscopic electrical and optical properties of polyimide molecules with eight structures, which saved time for subsequent experimental design. Then, we studied ordinary polyimide film, fluorinated polyimide film, and polyimide film with mica filler using experimental methods. We also analyzed the dielectric, electrical, and ageing properties of polyimide composites and finally prepared polyimide composites with excellent comprehensive performance.