Preparation and characteristics of polyimide/CaMoO sub(4) nanocomposites with enhanced dielectric performance and thermal stability

The polyimide/CaMoO sub(4) nanocomposites were successfully prepared by ex-situ polymerization. (3-Aminopropyl) triethoxysilane (KH550) was used as coupling agent to disperse the CaMoO sub(4) nanoparticles in polyimide matrix homogeneously. To characterize the structure and properties of the obtained nanocomposites, Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, dielectric properties and thermal stability were studied. It was observed that the CaMoO sub(4) nanoparticles were dispersed homogeneously in the polyimide matrix without obvious aggregation. The results show that nano-sized CaMoO sub(4) will improve dielectric constant and decrease dielectric loss of the nanocomposites in the relatively high-frequency region (>10 kHz). And the nanocomposite with excellent dielectric properties of epsilon =3.04, delta =8.010 super(-3) was obtained after doping 2.5 wt% nano-sized CaMoO sub(4) into polyimides. Dielectric loss of the nanocomposites is reduced in low frequency domain (10 kHz). In addition, the thermal stability of the nanocomposites was enhanced from 544 to 651 degree C compared to pure polyimide.