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Jipa S.,University Valahia of Targoviste | Setnescu R.,University Valahia of Targoviste | Setnescu R.,National RandD Institute for Electrical Engineering INCDIE ICPE CA | Zaharescu T.,National RandD Institute for Electrical Engineering INCDIE ICPE CA | And 3 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

Chemiluminescence (CL) and differential scanning calorimetry (DSC) were applied for proving the copper ion migration processes occurring within the low-density polyethylene (LDPE) electrical insulator as a consequence of intimate contact. Thin LDPE slides of 0.5 mm thick were subjected to short-time thermal stress at temperatures between 80 and 120 °C. Both CL and DSC kinetic parameters revealed the acceleration of post-treatment oxidation at elevated temperatures (170-200 °C) in copper-contacting polymer as in respect to the cases when Cu was absent. It was revealed that the oxidation rate measured by CL was more than two times higher for the samples heated in the presence of Cu than in its absence, while the oxidation induction time from DSC was considerably lowered for the same samples. Elemental analysis data provided by atomic absorption spectroscopy and particle-induced X-ray emission techniques as well as SEM investigations confirmed the presence of copper within the samples subjected to thermal treatment when the polymer insulation was in contact with the metallic conductor. Chemiluminescence procedure has a remarkable sensitivity to detect the effect of copper in the polymer matrix even at low concentrations. © 2015 Akadémiai Kiadó, Budapest, Hungary.


Jipa S.,University Valahia of Targoviste | Setnescu R.,University Valahia of Targoviste | Setnescu R.,National RandD Institute for Electrical Engineering INCDIE ICPE CA | Zaharescu T.,National RandD Institute for Electrical Engineering INCDIE ICPE CA | And 6 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

Chemiluminescence (CL) and differential scanning calorimetry (DSC) were applied for proving the copper ion migration processes occurring within the low-density polyethylene (LDPE) electrical insulator as a consequence of intimate contact. Thin LDPE slides of 0.5 mm thick were subjected to short-time thermal stress at temperatures between 80 and 120 °C. Both CL and DSC kinetic parameters revealed the acceleration of post-treatment oxidation at elevated temperatures (170-200 °C) in copper-contacting polymer as in respect to the cases when Cu was absent. It was revealed that the oxidation rate measured by CL was more than two times higher for the samples heated in the presence of Cu than in its absence, while the oxidation induction time from DSC was considerably lowered for the same samples. Elemental analysis data provided by atomic absorption spectroscopy and particle-induced X-ray emission techniques as well as SEM investigations confirmed the presence of copper within the samples subjected to thermal treatment when the polymer insulation was in contact with the metallic conductor. Chemiluminescence procedure has a remarkable sensitivity to detect the effect of copper in the polymer matrix even at low concentrations. © 2015 Akadémiai Kiadó, Budapest, Hungary.

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