Heat-resistant insulation film containing clay and wood components

Abstract In this paper, we prepared a novel organic–inorganic nanocomposite film with excellent insulation properties relative to the polyimide film in mild-processing conditions. The main component of the film is clay mineral and wood component, i.e., the layered silicate and poly(ethylene glycol)-modified lignin derivatives. In the nanocomposite film, an interlayer of silicate was bound by triethanolamine. Furthermore, the lignin derivatives filled the voids of the layered silicate, producing a defect-free densely packed nanocomposite film. This unique structure of the nanocomposite film provides high-thermal stability, a low thermal expansion coefficient of film consisting of clay and lignin derivatives, low gas transmittance rate, low volume/surface resistivity, and high dielectric breakdown voltage. The obtained nanocomposite film was installed in a planar-type transformer where it acted as an insulation film in the transformer coil with high dielectric breakdown voltage.