Excellent electrical performance and thermal properties insulation paper based on polyimide porous fiber membrane modified by nano-SiO2

Oil-paper insulation system is an important insulation structure of converter transformer. At present study, polyamic acid introduced was synthesized firstly, then perform electrospinning and thermal imidization to prepare polyimide (PI) porous fiber membrane, and the nano-SiO2 was introduced into the fiber membrane by in-situ polymerization. FT-IR was used to characterize PI porous fiber membrane chemical structure. Consequently, when the SiO2 addition amount is 4 wt.%, the breakdown voltage of the SiO2/PI composite fiber reaches the maximum, which is 74 kV/mm. The dielectric constant and dielectric loss of the composite fiber film are 1.98–0.0013 (107 Hz). It is worth noticing that nano-SiO2 available in PI significantly improved its electrical performance.