Title :
Gamma radiation effects in polyethylene naphthalate-electrical properties
Author :
Mackersie, J.W. ; Given, M.J. ; MacGregor, S.J. ; Fouracre, R.A.
Author_Institution :
Centre for Electr. Power Eng., Strathclyde Univ., Glasgow, UK
Abstract :
Samples of polyethylene naphthalate (PEN) film, 25 μm thick, have been exposed to gamma radiation doses of 26.4 kGy and 158.4 kGy. The electrical properties of virgin material and material exposed to these representative doses have been examined by two methods. The first is the response of the material to the application and removal of a step voltage and the second is thermally stimulated depolarisation current (TSDC) measurements. The former provided data on both the nominal DC conductivity as a function of temperature and, by transforming the transient current results to the frequency domain, the low frequency dielectric loss behaviour-also as a function of temperature. The TSDC measurements included both global spectra and partial polarisation spectra. Both types of measurement showed significant differences in behaviour associated with ageing of the sample material. It is also shown that effects due to processes activated at higher temperatures can be initiated by polarisation at much lower temperatures
Keywords :
dielectric losses; dielectric polarisation; dielectric thin films; gamma-ray effects; polyethylene insulation; polymer films; thermally stimulated currents; 10-5 to 10-1 Hz; 140 C; 15 min; 155 C; 158.4 kGy; 25 micron; 26.4 kGy; 30 min; 30 to 150 C; 60 min; electrical properties; frequency domain; gamma radiation effects; global spectra; low frequency dielectric loss; nominal DC conductivity; partial polarisation spectra; polyethylene naphthalate; response; step voltage; thermally stimulated depolarisation current; Conducting materials; Dielectric losses; Dielectric materials; Dielectric measurements; Gamma rays; Plastic films; Polarization; Polyethylene; Temperature; Voltage;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 2001 Annual Report. Conference on
Conference_Location :
Kitchener, Ont.
Print_ISBN :
0-7803-7053-8
DOI :
10.1109/CEIDP.2001.963516
