Improving electrical properties of SrTiO<inf>3</inf>/epoxy nanocomposites with high thermal conductivity

Abstract

SrTiO 3 /epoxy nanocomposites have been prepared via simple solution-processing technique by incorporating SrTiO 3 nanoparticles into the epoxy resin matrix with different loading amount 0wt%, 7wt%, 15wt%, 25wt%, 40wt% respectively. The morphology of the nanoparticles and composites, thermal conduction characteristic and electrical properties of the composites were investigated by multiples of conventional testing methods. FT-IR spectroscopy and TEM image showed that the surfactant KH550 would link the particles with epoxy resin matrix during the curing process which allowed a keen affinity between the matrix and the particles. It was found that the thermal conductivity increased with the SrTiO 3 weight fraction, Thermal conductivity of the SrTiO 3 /epoxy composite containing 40 wt% weight fraction was up to 0.37 W/m k. The uniformity of dispersion without pinholes or cracks seen from the SEM images could also enhance thermal conductivity and dielectric properties. The dielectric constant increased with the weight fraction and decreased with the frequency which indicated that the interfacial polarization and dipole polarization can't follow the change of electrical field direction at high frequency. However, dielectric constant at the frequency 1 kHz would increase with temperature which may result from the unique negative temperature coefficient characteristic, the shorter relaxation time and the intensification of molecule thermal motion. The functional composites would solve the key problem involving about intelligentization and miniaturization of the Gas Insulated Switchgear (GIS) and smart grid development deserving further research.