Thermal and electrical characterization of composite metal oxides particles from periwinkle shell for dielectric application

Rather than synthesizing metal oxides through chemical processes as fillers in polymer composites, metal oxides from natural sources (waste) could provide a cheaper and environmentally friendly alternative. In this work, a fine powder prepared from properly cleaned periwinkle shells was examined for its use as filler for polymer composites for high-voltage application. The powder was characterized using scanning electron microscopy (SEM), X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermal conductivity set-up and a programmable LCR Bridge. The SEM image of the powder revealed a range of particle sizes that vary from 2 to 34 mu m. The chemical analysis shows that CaO is the dominant metal oxide in the powder with 81.8 wt%. The dielectric constant and the electrical conductivity of the powder are 11.08 and 1.5876 x 10(-8) S m(-1), respectively, at the frequency of 200 Hz. The electrical conductivity of the powder is lower than the conductivity of pure CaO, while the thermal conductivity is slightly higher than that of pure CaO. This could be due to the influence of the other constituent metal oxides. The is an indication that periwinkle shell powder if properly processed to micro- and even nano-sized particles can be a good candidate as a filler in polymer composites to produce polymeric insulation with good insulating and thermal conducting properties.