This paper reports effects of ultraviolet (UV) light radiation on the physicochemical, electrical and mechanical properties of low-density polyethylene (LDPE) cable insulating materials. Changes in structural and morphological properties of UV-aged samples were characterized by various analytical methods such as attenuated total reflection Fourier transform infrared spectroscopy (ATRFTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Additionally, elongation at break, tensile strength, dielectric strength, and optical properties were also evaluated. Changes in some physical properties of LDPE after exposing to UV irradiation clearly highlighted that the polymer underwent the structural degradation. In addition, it was also found that such degradation yielded both crosslinking and chain scission as two competing processes during UV aging.

This article examines the influence of micro- and nanoscale calcium carbonate (CaCO₃) fillers on the dielectric behavior and aging resistance of polyvinyl chloride (PVC)-based composites. PVC films containing varying CaCO₃ contents (0%, 2.5%, 5%, and 7.5% by weight) were subjected to accelerated aging through prolonged ultraviolet (UV) exposure and thermal stress for up to 1248 h. The evolution of dielectric properties was characterized by impedance spectroscopy, while structural modifications were analyzed using Fourier-transform infrared (FTIR) spectroscopy. Additionally, changes in surface morphology, internal homogeneity (related to particle size, shape, and distribution), and chemical composition were investigated using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX), to evaluate the effects of irradiation and variations in the material’s surface composition and morphology. The results reveal a significant correlation between filler concentration and dielectric stability, highlighting the potential of CaCO₃ reinforcement to improve the long-term reliability of polymeric insulating materials. The results further highlight that beyond the amount of filler used, the fine-scale feature of CaCO₃, particularly its particle size and how well it is dispersed, has a significant impact on how the material responds to aging and maintains its dielectric properties.

This study focuses on isothermal charging and discharging currents in polystyrene (PS). It is a well known fact that the discharging current is almost the mirror symmetry of the charging current at low electric fields. However, the experimental results presented and discussed in this study have revealed the possibility of an abnormal discharging current (ADC) flowing in the same direction as the charging current. Furthermore, electrical measurements implied that the electrical ageing of PS resulted in a significant increase in the charging current, even for extended ageing periods. Moreover, the intensity and duration of the reverse discharging current have evolved with electrical ageing. This characteristic can be attributed to the presence of ionic impurities both trapped at the polymer surface and in the bulk structure. To highlight the structural changes induced by electrical ageing, detailed structural analyses were conducted using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis.

In this work, the effects of electrical aging on the structural and electrical properties of low-density polyethylene (LDPE) used as cable insulation are examined. Fourier-transform infrared spectroscopy spectroscopy revealed oxidative degradation characterized by the progressive formation of carbonyl groups, while scanning electron microscopy observations confirmed surface morphological changes induced by oxidation. LDPE films were subjected to intense partial discharges under an AC electrical field for 10 and 20 h, and their electrical performance was systematically evaluated. Measurements of DC resistivity, charging and discharging currents, polarization, and leakage currents demonstrated clear degradation of LDPE insulating properties with aging time. The decrease in surface and volume resistivity, the increase in charging and discharging currents, and the unexpected reduction in leakage current were directly correlated with structural and chemical modifications. Overall, the combined structural, morphological, and electrical analyses consistently show that electrical stress accelerates the structural deterioration of LDPE, providing reliable indicators of insulation performance loss.