TSDC of Irradiated and Non-Irradiated Cellulose Acetate

Document Type : Original Article

Authors

1 Dept. of Physics, College of Science and Humanities in Al-Kharj, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Kingdom of Saudi Arabia.

2 Polymer Research Group, Physics Dept., Faculty of Science, Mansoura University, 35516 Mansoura, Egypt.

3 Al-Mnsoura Specialist Hospital, 35511 Mansoura, Ministry of Health, Egypt.

4 Dept. of Physics, College of Science, Princes Nourah bint Abdulrahman University, Ryiadh, Saudi Arabia.

Abstract

Films of cellulose acetate (CA) have been prepared by casting method using tetrahydrofuran (THF). CA films are γ-irradiated with varying radiation doses of 10, 20, 30, 40, 50 and 60 kGy using cobalt-60 (60Co) source. Global thermally stimulated depolarization current (TSDC) of non-irradiated and irradiated CA samples has been investigated under the effect of various poling electric field (Ep) in a temperature range from 300 K to 440 K. It is observed that, global TSDC spectra of non-irradiated and irradiated CA samples are characterized by two relaxation peaks. One in the low temperature range ~321 K and the other in the high temperature range ~ 376-383 K are observed for non-irradiated sample. On the other hand, these temperatures are shifted towards lower temperature for irradiated samples to be located at 317 K and ~371 K. These relaxations are assigned as  and -relaxation and attributed to molecular motion of the polar acetate groups, C2H3O2 and polarization of the space charges, respectively. TS-technique has been carried out to decompose global TSDC spectra of all samples into its elementary peaks and the molecular parameters such as, activation energy and pre-exponential factor are calculated for each TS peak. Relaxation map (RM) of all samples has been analyzed using Eyring transformation and thermodynamic parameters such as, enthalpy activation (H), entropy activation (S) and Gibbs free energy (G) are estimated. The compensation phenomenon was verified by the linear relationship between both enthalpy and entropy.

Keywords

Egyptian Journal of Chemistry
Volume 64, Issue 5
May 2021
Pages 2453-2468

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History

  • Receive Date: 07 January 2021
  • Accept Date: 10 February 2021

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