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Electrical insulation properties of silicone rubber under accelerated corona and thermal aging
Author(s) -
Belhiteche El Hadi,
Rondot Sébastien,
Moudoud Mustapha,
Dony Philippe,
Jbara Omar
Publication year - 2021
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.25610
Subject(s) - materials science , silicone rubber , composite material , polymer , scanning electron microscope , attenuated total reflection , surface roughness , accelerated aging , fourier transform infrared spectroscopy , chemical engineering , engineering
A contactless method based on energy shift of high‐energy cut‐off of the x‐ray bremsstrahlung, the so‐called Duane Hunt Limit and a conventional low voltage electrical technique (three‐probes technique) is applied on thermal and corona aged silicone rubber (SiR) to measure, respectively, the surface potential, V s , and the surface resistivity, ρ s . The effect of aging on these quantities, representing the dielectric properties, is studied. The results are highly reproducible and highlight a good correlation between V s and ρ s . It was observed that thermal aging combined with electrical aging deteriorates more the electrical properties of the polymer than thermal aging alone. Explanations for electrical characteristics ( V s , ρ s ) change with aging are supported by attenuated total reflection Fourier transform infrared spectroscopy spectra analysis and a chemical mechanism of aging in three steps (i.e., oxidation‐polycondensation, degradation, and thermal cracking). The surface degradation of the polymer is revealed by images of surface morphology obtained by using scanning electron microscopy (SEM). Roughness is greater for combined thermal and corona aging mode compared to thermal aging alone. In addition, the surface degradation of SiR polymer is confirmed by the loss of its hydrophobicity.