Thermally stimulated currents (TSC) on new and field-agedunderground cable material

摘要

Field-aged and unaged cable material have been investigated withthe TSC technique. Two well defined relaxation modes have been observedfor both materials: one high temperature peak (α) at about 115° C that can be related to the melting of the crystalline phase ofthe polymer and one low temperature peak (β) located at about -300° C that can be associated with the glass-rubber transition.Comparison between both sample spectra have shown some noticeabledifferences. The field-aged material exhibited: (1) lower magnitudeofthe a peak; (2) slightly higher magnitude and temperature shifttowards higher temperature for the β peak; (3) higher density and(4) lower melting enthalpy