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.
