Papers by Keyword: DC Breakdown

Abstract: To improve the agglomerate phenomena of polarity nanosized MgO-filler in non-polar low density polyethylene (LDPE) matrix, in the composite (MgO/LDPE) master batch preparation process, adding a certain amount of ethylene-vinyl acetate copolymer (EVA), in order to improve the compatibility of nanoparticles and matrix materials. The dispersion states of MgO in the MgO/LDPE and EVA/MgO/LDPE composite material was evaluated by using scanning electron microscope (SEM), results shown that compared with MgO/LDPE nanocomposite, the dispersion of EVA modified MgO/LDPE is better and the agglomerate phenomena is not seen. DC breakdown tests shown that EVA modified MgO/LDPE compared with other several kinds of materials (LDPE; EVA/LDPE; MgO/LDPE and EVA/MgO/LDPE); the DC breakdown strength has improved significantly.

Abstract: Electrical breakdown field measurements on Polymethylmethylacrylate (PMMA) and a nano-composite of PMMA/Barium Titanate (BTA) by 10% wt are presented. The measurements were made using uniform field electrode configuration under high voltage DC. The electrodes were made of stainless steel, each having a Bruce profile, and diameter 25 mm. The measurements were made at room temperature (293 K) and liquid Nitrogen temperature (77 K). Using Weibull statistics it shows that both PMMA and the nano-composite have breakdown electrical field strengths much higher at 293 K than at 77 K. It has been shown that there was very marked improvement in the reliability of results for both compounds at 77 K over those at 293 K. The SEM micrographs have shown very distinct differences in the behavior of the nano-compound between 293 K and 77 K, PMMA also exhibit some clear differences.