Electrical Properties of Silver-Silicone Rubber Nanocomposites for High-Voltage Outdoor Insulators

Currently, the selection of high-temperature vulcanizing silicone rubber (HTVSiR) formulations resistant to the growth of microorganisms and which suitable electrical properties plays an important role in the manufacture of the polymeric high-voltage outdoor insulators (HVOIs) with high lifetime. In this work, silver-HTVSiR nanocomposites (AgHTVSiR) formulations are prepared and their electrical and antimicrobial properties are presented. Ag nanoparticles were electrochemically synthesized and characterized by scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), UV-visible (UV-Vis), and X-ray (XRD) spectroscopies. Thermogravimetric (TG/DTG) analysis is undertaken with the purpose of determining the thermal behavior of AgHTVSiR. The complex impedance analyses were conducted to investigate the electrical conduction mechanism of the AgHTVSiR nanocomposites via electrochemical impedance spectroscopy (EIS) within a frequency range from 0.1 Hz to 0.1 MHz. XRD revealed Ag nanoparticles of 50 nm in diameter size. The images of SEM-EDS evinced the homogeneity of Ag nanoparticles dispersion into the HTVSiR matrix. The incorporation of silver nanoparticles does not change the thermal stability of the AgHTVSiR nanocomposite as compared to neat HTVSiR. The AgHTVSiR nanocomposites have maximal values for real part (
${Z} ^{\prime} $
) at low frequencies.
${Z} ^{\prime} $
is found to decrease as the frequency of the applied alternating electric field increases. Furthermore, there is an improvement in the permittivity values for the AgHTVSiR nanocomposites with an increase in the concentration of 0.1 wt.%–0.3 wt.% of the Ag nanoparticles. Also, the AgHTVSiR shows excellent antimicrobial efficacy against Trichoderma spp fungus. The impedance characteristics of the AgHTVSiR nanocomposite along with its high dielectric permittivity and excellent antimicrobial property make it suitable for application in HVOI.