Effect of Temperature and Water on the Aging Characteristics of Novel High Voltage Polyamide Nanocomposite insulators /

Abstract

The polymers used in the field of cable insulation experience degradations due to heat and moisture in the field. This study was performed to analyze such effects on surface deterioration and structural changes of polyamide and its nanocomposites with zinc oxide inclusion. Neat polyamide (PA0) and its nanocomposite with 1 wt%, 3 wt%, 5 wt% and 7 wt% of filler loading were prepared and subjected to accelerated hydrothermal aging in programmable chamber. The samples were investigated with visual inspection, optical microscopy, hydrophobicity measurements, Fourier Transform Infrared (FTIR)spectroscopy, leakage current measurement and UV-Vis spectroscopy. The confirmation of gradual degradation due to thermal-oxidation and hydrolysis was done with these analyses. The contact angles of 75°, 99.5°, 112°, 97° and 80° were exhibited by PA0, PA1, PA3, PA5 and PA7 respectively, after 300h aging. After 3 cycle of aging, the PA0, PA1, PA3, PA5 and PA7 showed 6.75 µA, 6.58 µA, 6.5 µA, 6.8 µA and 6.83 µA of leakage current respectively. In C-C stretching, 38 %, 14 %, 9.4 %, 48 % and 52 % decrement was observed in PA0, PA1, PA3, respectively. Oxidation was also seen with an increase of carbonyl group. However, it was observed that the addition of nanofiller enhanced the overall performance of composite insulation. Nanocomposite having 3 wt% of nanofillers exhibited higher contact angle of 112°, lower leakage current of 6.5 µA, lower surface degradations, higher band gap energy 5.23 eV and decrease of 9.4% in C-C stretching as compared to all other sample. The addition of fillers in precise percentage improved the polymer-filler interaction due to its large surface area and energy.