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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:36 |
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Conference: Bucharest University Faculty of Physics 2010 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
Coincidence Doppler Broadening Spectroscopy on Polymers
Authors:
M. Straticiuc (1,2), C. M. Barna (1,2), I. Burducea (1,2), F. Constantin (1)
Affiliation:
(1) Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HH, Str. Atomistilor no.407, Magurele – 077125, Ilfov, Romania
(2) Atomic and Nuclear Physics Chair, Faculty of Physics, University of Bucharest, Romania
E-mail
mstrat@nipne.ro
Keywords:
CDBS, polyurethane, nanostructures
Abstract:
Despite the general use of positron annihilation lifetime spectroscopy (PAL) in polymer studies we present a new approach in probing the chemical environment of the free volume holes in polymers by the use of the Doppler broadened annihilation energy line.Coincidence Doppler Broadening Spectroscopy (CDBS) measurements were performed on gamma-irradiated polyurethanes nanostructure samples with and without the silver ions in the nanofibers matrix. It is shown that, after a certain gamma irradiation, the momentum density distributions of annihilation electrons have changes for the high dose irradiated polyurethane, but no significant changes have been observed for the low dose irradiated polyurethane. The irradiation procedure consisted in using gamma radiation at 30-35 kGy/h exposure fluency, up to 100 kGy absorption dose, and temperature at 25°C. Electron paramagnetic resonance (EPR) measurements were also made. The results show a peculiar behavior of the silver ions in modifying the chemical environment of the free volumes.
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