Synthesis, characterisation and enhanced properties of polyimide/mica hybrid films

Abstract

ABSTRACTPolyimide/mica (PI/mica) hybrid films were prepared from pyromellitic dianhydride/4,4-bis(3-aminophenoxy)biphenyl (PMDA/4,3-BAPOBP) and mica in a solution of N,N-dimethylacetamide. The structure–property relationships of the composites were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible spectroscopy and differential scanning calorimetry. FTIR indicated successful preparation of PI/mica hybrid films. XRD and SEM results indicated that the mica was well dispersed in the PI matrix. The dependence of morphology, glass transition temperatures (Tg), dielectric properties and mechanical properties at room temperature of the hybrid films on the content of mica was discussed. It was observed that Tg, the breakdown strength and tensile strength of the hybrid films, could be simultaneously increased when the mica content was lower than 8 wt-%. Meanwhile, the dielectric constant and dielectric loss of PI/mica hybrid films increased with the increase in the mica content.