Thermally stimulated depolarization current and space charge measurements on low‐density polyethylene: Influence of the presence of antioxidant

Abstract

The purpose of this study is an investigation upstream of polymer insulator ageing and rupture. We studied the electrical and physicochemical properties of a low-density polyethylene (LDPE) used in high-power insulated cables. Space charge measurements using pulsed electroacoustic method and thermally stimulated depolarization current (TSDC) were carried out on LDPE samples, with and without antioxidant, at different temperatures. TSDC peaks were observed only in the presence of an antioxidant. Furthermore, a TSDC anomalous peak was revealed for the sample containing an antioxidant and polarized at 508C. All the TSDC peaks are interpreted as trapped charges and can be explained by measuring the space charge distribution within the sample bulk.

Morphology‐related packetlike space‐charge behavior in linear low‐density polyethylene doped with Al2O3 nanoparticles

“…The structural charge traps partly depend on the material morphology. The significant influence of the polymer morphology on the carrier transportation has been revealed by many authors 12–15. However, the relationship between the migration of the packetlike space charge and the material morphology has not been revealed.…”

Numerical simulation of thermo-stimulated depolarization currents in polyethylene films

“…Furthermore, the " and # peaks are located at the same temperature as the C3 and C4 peaks shown by Mizutani et al [7] These peaks are assigned to the presence of defects, acting as deep traps (0.8 at 1.4 eV) and located in the amorphous-crystalline interface [7], or in the crystalline region [8]. Moreover, the " and # relaxations are only observed in the case of LDPE with antioxidant [9] so the antioxidant most probably acts as deep trap and is also responsible for the polymer morphological change. …”

Electrical conductivity of waxes as model systems for polyethylene: Role of water

“…In terms of the values in Table (where the sum total of all fractions adds up to 100 wt %) this implies a minimum detectable impurity concentration of ~0.02 wt % or 200 ppm. In contrast, a commercial PE contains antioxidants at typical concentrations of 0.05–1 wt % and other additives, such as flame retardants, may be present in even greater proportions . Therefore, compared to commercial PE, PW is a very clean system indeed.…”

“…The relative abundances were determined by integration but, due to the uncertainties introduced through estimation of a suitable baseline, the values are calculated to an accuracy of 0.1% (Table I). PW is composed of 18 distinct homologues ranging from C 20 H 42 to 19 and other additives, such as flame retardants, may be present in even greater proportions. 20 Therefore, compared to commercial PE, PW is a very clean system indeed.…”