Thermally stimulated depolarization currents of crosslinked polyethylene relaxations in the fusion range of temperatures

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 41; no. 12; pp. 1412 - 1421
• Main Authors: Tamayo, I., Belana, J., Cañadas, J. C., Mudarra, M., Diego, J. A., Sellarès, J.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.06.2003; Wiley
• Subjects: Applied sciences; charge transfer; crosslinked polyethylene (PE); crosslinking; Electrical, magnetic and optical properties; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; polyethylene (PE); Properties and characterization; space charge; thermostimulated depolarization current; windowing polarization; Polyethylene; polyethylene (PE); thermostimulated depolarization current; Space charge; Experimental study; charge transfer; Dielectric relaxation; Thermostimulated depolarization; Charge carrier trapping; Thermal history; Crosslinked polymer; crosslinked polyethylene (PE); crosslinking; windowing polarization
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.10489

With thermally stimulated depolarization currents, we researched the relaxations of crosslinked polyethylene as it is used in medium‐voltage cable insulation. Through conventional polarization two heteropolar peaks stand up in the spectra, at 80 and 105 °C. As the sample is annealed, a homopolar peak is developed at about 99 °C. With window polarization, our results indicated that the 80 °C peak is a structured peak related to polar crosslinking subproducts and impurities. The 105 and 99 °C peaks are fitted to the general kinetic‐order model because the 105 °C peak is related to free‐charge detrapping at the crystalline phase, in the bulk and maybe at the amorphous‐crystal interphases, and the peak that is observed at 99 °C is due to injected charge. Annealing at high temperatures promotes the creation of traps in the material. Charge trapping at T < 70 °C seems to be related to the increased insulator resistivity with annealing time. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1412–1421, 2003