On the nature of thermally stimulated discharge current spectra in polyethylene terephthalate

Abstract

Thermally stimulated depolarization currents (TSDC) in polyethylene terephthalate (Hostaphan) films of different thickness (12, 25, and 50 μm) have been investigated under different environmental conditions in the temperature range of 20–150 °C. Two peaks of TSDC spectra observed at approximately 80 and 125 °C originate from a dipolar process (α peak) and a space-charge relaxation (ρ peak), as evidenced from the variation of parameters such as electrode geometry and polarizing voltage. A numerical method (Tikhonov regularization procedure) has been employed to determine the most probable values of effective frequency factors of dipolar and space-charge relaxation in polyethylene terephthalate. An apparent influence of environmental pressure on the location of the α peak has been observed whose origin is yet to be determined.

TSDC study of structural relaxation on polyethylene terephthalate

“…The a peak appears close to the glass transition temperature as determined by DSC, and can be attributed to the micro-Brownian motions of large chain segments. The value 4.03 eV of the activation enthalpy calculated by peak integration method [22,23], in the vicinity of the glass transition characterizes a main relaxation mode [24]; this value is close to that calculated by Neagu et al [22]. The high temperature peak (q-peak), whose origin is related to space charges [25] depends strongly on sample preparations and poling conditions.…”

Insight into What Is inside Swift Heavy Ion Latent Tracks in PET Film

“…We use the term electrification, following [39], because of the difference between our experimental scheme and that which is generally used in electret studies. See, for instance, [17,18,25,40]: in [40], the polarization of samples of PET films from the same manufacturer with a thickness of 12 to 50 µm was performed using aluminum electrodes and unipolar corona discharge at voltages up to 100 V for 5 min at temperatures above the glass transition temperature.…”