KH550-SiO2/polyimide insulating paper preparation and characterisation

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, SiO₂ nanoparticles were modified with a silane coupling agent (KH550), and the KH550-SiO₂ 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-SiO₂, and the dielectric strength reached its maximum value of 85 kV/mm. The results demonstrate that the insulation performance of the KH550-SiO₂/PI composite was significantly improved due to the incorporation of nano-SiO₂. This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550-SiO₂/PI fibre membrane.