The synthesis and dielectric study of BaTiO3/polyimide nanocomposite films

Polymer-ceramic dielectric composites have been of great interest because they combine the processability of polymers with the desired dielectric properties of the ceramics. A novel, simple method to make thin, homogeneous composite films with varying amounts of ceramic filler content has been proposed. Nanocomposite thick films of barium titanate (BaTiO3) in polyimide (PI) from 3,3,4,4'-benzophenone tetra carboxylic dianhydride, 4,4'-oxy dianiline have been successfully prepared by in situ imidization using n-methyl pyrrolidinone as the solvent. The dielectric properties of the nanocomposite films were discussed for various filler volume contents. These nanocomposite films exhibited stable dielectric properties in the various frequency ranges. Films were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermo gravirnetric analysis (TGA), and differential scanning calorimetry (DSC). The curing cycle was optimized using FTIR. XRD results confirm BaTiO3 particles remain unchanged in the PI matrix and no undesired secondary phases are present in the films. Their glass transition behavior and thermal stability were investigated by DSC and TGA, and the films were stable to 300 degrees C. Scanning electron microscope images show that the BaTiO3 phase is well dispersed in the polymer matrix. (c) 2005 Elsevier B.V. All rights reserved.