Synchronous enhancement on the thermal stability and electric property of polyimide by introducing the hybrid of sericite and SiO2

Abstract

The hybrid of sericite and SiO2 was synthesized by the sol-gel method. Fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM) results indicated that the SiO2 had well formed on the surface of sericite, and the inner structure of the hybrid was characterized by x-ray radiation (XRD). Then PI/sericite-SiO2 composites were obtained by blending the hybrid with polyamide acid (PAA) and subsequently thermal imidization. It was shown that the thermal stability of PI/sericite-SiO2 composites was obviously improved with moderate content of the hybrid, and the onset degradation temperature and the residues both increase compared with that of pure PI and PI-raw sericite. Simultaneously, the resistivity and the intensity of electric shock properties of PI/sericite-SiO2 composites had been both considerably improved with the optimum ratio of the hybrid, which is mainly attributed to the formation of inorganic insulative network by incorporating the hybrid in PI matrix, as revealed by the results of SEM images and the XRD pattern.