KH550‐SiO 2 /polyimide insulating paper preparation and characterisation

Abstract Oil‐paper insulation material is an essential component for oil‐filled transformers, and polyimide (PI) insulation paper is a novel material in the field of electricity. The improvement of insulation class for insulation paper has gained significant attention in recent years. In this study, SiO 2 nanoparticles were modified with a silane coupling agent (KH550), and the KH550‐SiO 2 was added to the fibre membrane through in situ polymerisation. The chemical composition and microcosmic characteristics of the PI porous fibre membrane were characterised using FT‐IR and SEM FT‐IR and SEM. Consequently, the dielectric constant of the composite paper was reduced to 2.3 upon adding 3 wt% of KH550‐SiO 2 , and the dielectric strength reached its maximum value of 85 kV/mm. The results demonstrate that the insulation performance of the KH550‐SiO 2 /PI composite was significantly improved due to the incorporation of nano‐SiO 2 . This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550‐SiO 2 /PI fibre membrane.