Thermally stimulated depolarization current spectra of cross‐linked polyethylene and the influence of cross‐linking byproducts. Issue 22 (2nd October 2020)

• Record Type: Journal Article
• Authors: Walker, Roger C; Hamedi, Hossein; Woodward, William Hunter; Lanagan, Michael
• Is Part Of: Journal of polymer science. Volume 58:Issue 22(2020)
• Page Start: 3142
• Page End: 3152
• Publication Date: 2020-10-02
• Subjects: acetophenone -- antioxidant -- methylstyrene -- oxidation -- polyethylene -- space charge -- thermally stimulated depolarization current; Polymers -- Periodicals; Polymerization -- Periodicals; Polymerization; Polymers; Periodicals; 547.7
• DOI: 10.1002/pol.20200470
• Languages: English
• ISSNs: 2642-4150

Abstract

Abstract: Cross‐linked polyethylene (XLPE) is notable for its use as power cable insulation. Its longevity is limited by space charge buildup linked to impurities such as the byproducts left behind by the cross‐linking agent dicumyl peroxide (DCP). The goal of this work is to determine the impacts of these byproducts on charge trapping and detrapping in XLPE using the thermally stimulated depolarization current technique. XLPE with byproducts has one source of trapped charge, which originates from the byproducts. XLPE that was thermally treated via degassing exhibits two other sources of trapped charge, which are charge injection and dipolar relaxations. Oxidation from degassing was shown to control the trapping from these sources, which is useful knowledge for processing this material prior to its use. Reintroducing acetophenone, one of the major byproducts of DCP, suppresses those two peaks once more, showing that it controls the overall space charge buildup characteristics in XLPE. Abstract : The electrical properties of cross‐linked polyethylene (XLPE) are relevant for power cable applications. Charge trapping and detrapping in XLPE is examined in this work using the thermally stimulated depolarization technique. Under the as‐received condition, there is one main source of trapped charge–cross‐linking byproducts such as acetophenone (ACP) and water. Thermal treatments like degassing alter the resulting thermally stimulated depolarization current spectra by removing ACP and leaving behind water, thus revealing the intrinsic trapping characteristics of XLPE.