Features of the Charge State of UHMWPE + α-SiO2 Nanocomposites

• Published in: Surface engineering and applied electrochemistry 2020-05, Vol.56 (3), p.267-271
• Main Authors: Ismayilova, R. S., Kuliev, M. M.
• Format: Article
• Language: English
• Subjects: Amorphous materials; Charge density; Composite materials; Current carriers; Depolarization; Electrets; Electrical resistivity; Engineering; Machines; Manufacturing; Nanocomposites; Nanoparticles; Polymer matrix composites; Processes; Radiation dosage; Room temperature; Silicon dioxide; Surface charge; Surface layers; Thermal stability; Ultra high molecular weight polyethylene
• ISSN: 1068-3755; 1934-8002
• DOI: 10.3103/S1068375520030060

— This paper presents the results into the study of electret properties of composite materials based on ultrahigh molecular weight polyethylene (UHMWPE) and nano-dispersed amorphous silica filler α-SiO 2 (aerosil) depending on the volume content of silicon dioxide and the absorbed dose D γ-irradiation at room temperature using the method of thermally stimulated depolarization (TSD). It was found that introducing up to 5% of spherical nanoparticles of amorphous α-SiO 2 silicon dioxide with a diameter of 20 nm in UHMWPE first increases and then reduces the electret characteristics of the composites. UHMWPE + 1% α-SiO 2 has the maximum value of the electret potential difference and the stability of the electret state. It was shown that preliminary γ-irradiation affects the electret properties of the studied composite material, which is associated with its increased electrical conductivity and a high charge relaxation rate. The observed increase in the initial surface charge density σ el of UHMWPE compositions is associated with the presence of energy traps of injected charge carriers. Based on the analyzing the spectra of TSD, it was shown that the thermal stability of electrets from the UHMWPE composite + 1% α-SiO 2 is improved. The nature of the TSD current of pre-γ-irradiated films once again proves that, after γ-irradiation, the injected charges from the corona zone mainly accumulate in the near-surface layers of the irradiated samples. The results of TSD suggest that the relaxation of the electret state in the materials under study occurs due to the bulk conductivity.