Aging Investigation of Polyvinyl chloride with zinc oxide micro-fillers for High Voltage and High-temperature Applications /

Abstract

Polyvinyl chloride and its composites are used for high-voltage cable insulation. Due to the organic nature of PVC insulators, which degrades due to the electrical and thermal stresses. This study investigated the effect of thermal and electrical stresses on the surface morphology of polyvinyl chloride and its composites. To analyze these effects, neat polyvinyl chloride (PZ0) and its micro-composites are 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25wt.%, and 30 wt.% of zinc oxide were prepared and subjected to an accelerated electrothermal chamber for 200 hours. The samples were analyzed with visual inspection, optical microscopy, STRI hydrophobicity, contact angle, FTIR, Leakage current, and UV-Vis spectroscopy. Through XRD, the presence of ZnO in the polyvinyl chloride matrix was confirmed. Visual inspection and optical microscopy are used to observe surface roughness and material loss. STRI and contact angle are performed to analyze surface hydrophobicity. The contact angle of PZ0, PZ5, PZ 10, PZ 15, PZ 20, and PZ 30 is 98.95o, 87.35o, 97.65o, 100.4o, 83.35o, and 83.75o, respectively. PZ 15 shows better performance than other composites at the end of 200h aging. FTIR is used to analyze the chemical binding and functional group. At 1719 cm-1, there is an increase in carbonyl function group absorbance which causes oxidation. From the FTIR spectrum, it has been proved that PZ 15 performs better under electrothermal aging than other samples. UV-Vis spectroscopy is performed to analyze the bandgap energy. To measure the surface resistance of samples dc leakage current has been performed. PZ 15 has a minimum leakage current which is 0.36 μA while other composites PZ 0, PZ 5, PZ 10, PZ 20, PZ 25, and PZ 30 have 0.531 μA, 0.55 μA, 0.44 μA, 0.388 μA, 0.436 μA, and 0.620 μA, respectively. In summary, during this study overall PZ 15 shows resistance to degradation under electrothermal stress. It is due to the optimal concentration of ZnO, and better interaction of fillers with PVC which enhances the properties of polyvinyl chloride. Moreover, with the addition of ZnO micro-fillers, the micro-composites performed better than neat polyvinyl chloride due to its large surface area and energy.