Quantitative EPR study of poly(vinylidene fluoride) activated by electron beam treatment

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Mohsen Sadeghi Bogar - , Institute of Lightweight Engineering and Polymer Technology (Author)
  • Sabine Beuermann - , Clausthal University of Technology (Author)
  • Evgenia Dmitirieva - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Marco Drache - , Clausthal University of Technology (Author)
  • Uwe Gohs - , Institute of Lightweight Engineering and Polymer Technology (Author)
  • Ulrich Kunz - , Clausthal University of Technology, Energie-Forschungszentrum Niedersachsen (Author)
  • Torben Lemmermann - , Clausthal University of Technology, Energie-Forschungszentrum Niedersachsen (Author)
  • Marco Rosenkranz - , Leibniz Institute for Solid State and Materials Research Dresden (Author)
  • Maria Stehle - , Clausthal University of Technology (Author)
  • Carsten Zschech - , Leibniz Institute of Polymer Research Dresden (Author)

Abstract

The electron paramagnetic resonance (EPR) spectra of poly (vinylidene fluoride) (PVDF) films were studied in order to identify type and intensity of trapped radicals after an electron treatment with 150 kGy in air at room temperature. The observed EPR spectra consist of superimposed spectra of eight different radicals. The individual spectra were simulated by first derivatives of normalized Gaussian functions including intensity, linewidth, g value, and hyperfine splitting constants of the unpaired electron with hydrogen or fluorine atoms in α or β positions. In addition, the number of trapped radicals was estimated using a standard sample of known spin concentrations. Although initially generated radicals tend to be converted to peroxy radicals in the presence of oxygen, the predominant radical is the CH-based mid-chain radical (–CF2–C*H-CF2-) with a relative intensity of 62.3%. This is attributed to CH-based radicals in the crystalline domains with low molecular mobility leading to an enhancement in its linewidth (ΔHpp ⁓ 3.6 mT). A fraction of 20.7% of all radicals are peroxy radicals with anisotropic g values, g = 2.0210 and g = 2.0095. The relative intensity of allyl, dienyl and polyenyl radicals amounts to 4.9%.

Details

Original languageEnglish
Article number109421
JournalRadiation Physics and Chemistry
Volume184
Publication statusPublished - Jul 2021
Peer-reviewedYes

External IDs

Scopus 85103343035

Keywords

Keywords

  • Air atmosphere, Electron beam modification, EPR analysis, Membrane, PVDF