Analysis of the TSD spectra of polymers near the glass transition temperature using the fractional purification method

Abstract

In this work, the thermally stimulated spectroscopy methods are applied to PET films exposed to UV rays for the analysis of electrically active defects parameters in these materials, such as activation energy (E a ) and relaxation time, or frequency factor (ω). To obtain these parameters the methods of thermally stimulated currents and thermally stimulated currents thermal sampling were used. To determine the relaxation parameters using the methods of thermally stimulated currents, various mathematical methods of data processing were used. The Eyring equation and the compensation law were found to be the most correct for PET films. The value of the activation energy determined with their help for the PET exposed to UV rays turned out to be 1.07 eV, and the value of effective frequency factor ω = 1/τ 0 = 5 × 10 10 с −1 .

Molecular mobility research in polyethylene composite films

“…However, in many cases, e. g., near glass transition temperatures and mechanical relaxations of polymers, the use of traditional methods of experimental results processing for thermal activation spectroscopy leads to abnormally high values of activation energy of E a electrically active defects (EAD) participating in the relaxation process and unrealistic relaxation time values less than 10 −20 seconds (Shabanova, Temnov 2021). This is due to the fact that in this case the relaxation process involves the cooperative movement of molecular chain segments, and the precise determination of the activation energy of one relaxer requires taking into account the change in the free volume of the polymer during the relaxation transition.…”

“…Figs. 2-3 show the curves of the TSD in the temperature range of α-relaxation obtained for LDPE samples with 5% and 20% of technical carbon obtained with fractional purification (Shabanova, Temnov 2021).…”