Electrical and mechanical property study on three-component polyimide nanocomposite films with titanium dioxide and montmorillonite

Polyimide (PI)-matrix composite films containing titanium dioxide (TiO ₂) nanoparticles and layered montmorillonite (MMT) have been fabricated by employing in-situ polymerization and their microstructure has been investigated by synchrotron radiation small angle X-ray scattering, wide-angle X-ray diffraction and scanning electron microscopy. The effects of mixture doping concentration on volume resistivity, loss tangent, permittivity, and breakdown field strength are analyzed. The breakdown field strength of TiO ₂ and MMT doped PI nanocomposite (PTM) shows a maximum value at the inorganic content of 5 wt.%, which is 10% higher than that of comparable two-component PI/TiO₂ nanocomposite films. Meanwhile, the tri-layered PTM/PI/PTM nanocomposite film, prepared by in-situ polymerization, exhibits improved electrical properties than that of the monolayer PTM film.