Electroconductivity and Dielectric Permittivity of γ-Irradiated Composites Based on Ultra High Molecular Polyethylene with α-SiO₂

Abstract

UDC 541.64:539.26:537.529

DOI  https://doi.org/10.5281/zenodo.1053487

Ultra-high-molecular polyethylene (UHMPE)/ SiO₂ composites were obtained from a homogeneous mixture of UHMPE and silicon dioxide powders by hot pressing method. Under study were: the temperature dependence (20–170°С) of their conductivity σ_dс before and after γ-irradiation (D = 200 kGy); the influence of the absorbed dose on the value of σ_dс (dose dependence), as well as the behavior of the function lgσ_dc = f(T) under the conditions of heating-cooling and the frequency dependence (25–10⁶ Hz) of the real (ε^/) and imaginary (ε^//) parts of the complex dielectric permittivity. It was shown that the dependence lgσ_dc= f(T) in both cases has a compli-cated character: "fractures" are observed resulting from the phase transition. With an increase of the α-SiO₂ concentration in the matrix, a growth in the values of ε^/ and ε^// (tgδ) is observed, whereas the dependence of these values on frequency corresponds to the exponential law.

Keywords: ultra-high-molecular-polyethylene, UHMPE+α-SiO₂ composite, dielectric loss, dielectric permittivity, electric conductivity, frequency, γ-irradiation.