Preparation and study on the electrical properties of polyimide / TiO2hybrid films

Polymer-matrix insulating materials are widely used in electrical and electron engineering owing to their excellent mechanical properties, thermal and dielectric properties. Polyimide/TiO₂ nanocomposites have been prepared by the polymerization process of adding nano-TiO₂ inorganic nanoparticles in polyimide. The structure of nanocomposite films was characterized by FTIR and SEM. The FTIR results confirm the formation of TiO₂ particles in the PI matrix. The homogeneous dispersion is observed by the SEM, it shows that the phase of TiO₂ was well dispersed in the polymer matrix. Finally the electrical properties of the PI/TiO₂ nanocomoposites with nano-TiO₂ loading from 1%-7% have been investigated. The results show that the breakdown strengths of nano-TiO₂ filled polyimide film are deteriorated with the increasing of nano-TiO₂ loading, however the breakdown strength reaches its maximum value when the concentration of loading is 1 wt. %. Meanwhile, the relative dielectric constant and the dissipation factor are increased with nano-TiO₂ loading.