Effect of Nanofiller Calcination on Breakdown Performance of Silica Based Polyethylene Nanocomposites

Polymer nanocomposites have become one of the main research studies in investigating the potential use of new dielectric materials especially in high voltage insulation. Many promising results, especially on the use of polyethylene nanocomposites as dielectric materials, have been reported in the literature. Significantly, the main factor that affects the dielectric performance of the materials was attributed to the interface between the host matrix and the nanofiller. This paper reports on an investigation into the AC and DC breakdown performance of unfilled and polyethylene nanocomposites containing silicon dioxide (SiO2) nanofillers at different loading levels (1 wt%, 4 wt%, and 8wt%). By using the Fourier transform infrared (FTIR) spectroscopy, the chemical structures of the materials were characterized. The dielectric permittivity of the samples was analyzed using dielectric spectroscopy. From the breakdown results, it showed that AC breakdown testing did not result in significant changes on the breakdown strength between uncalcined and calcined nanofillers. Meanwhile, for DC breakdown testing, introducing a small number of nanofillers could have a major impact on the DC breakdown strength. These results were correlated with the calcination process of nanofiller; the DC breakdown strength improved for calcined nanofiller compared to uncalcined nanofiller.