Advanced Physical Research

In this study, for the first time, a composition based on high-pressure polyethylene (LDPE) grade 10803-020 has been developed, notable for its exceptionally low additive content (0.05 wt% each) and excellent technological compatibility. The results of experiments investigating the effect of small amounts of phthalic anhydride (PhAn) and phthalic acid (PhAc) additives on the lifetime and dielectric properties (tgδ, ρv) of high pressure polyethylene (HPPE) film grade 108 are presented. It was found that the optimal concentration is 0.05 mass% PhAn + PhAc, which increases the electrical strength by about 50% and significantly improves the dielectric properties compared to the original HPPE. The dielectric characteristics of the loss tangent , specific volume electrical resistivity (ρ_v), and dielectric permittivity (ε) were studied. In the optimal HPPE composition, there is a significant increase in specific volume electrical resistivity and a decrease in the loss tangent (tgδ), indicating a strong correlation between these characteristics. To identify structural changes in the polymer materials before and after the introduction of small additives and exposure to discharges, research was conducted using scanning electron microscopy and dilatometry methods. These methods were used to study the effect of the small additive (PhAn + PhAc) on the crystallization rate and mechanism of high pressure polyethylene. It was found that the introduction of 0,05% by mass of PhAn + PhAc into HPPE influences the increase in polymer crystallization rate and improves polymer processing productivity.