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    ESR investigations on gamma-ray irradiated 3-methyl nylon 3
    (Elsevier B.V. All, 2008) Çatıker, Efkan; Güven, Olgun; Özarslan, Özdemir; Chipara, Mircea
    Electron spin resonance spectroscopy investigations on gamma irradiated 3-methyl nylon 3 (poly-3-methyl beta-alanine) are reported. The resonance spectra (recorded after the irradiation in nitrogen atmosphere has been stopped) have been attributed to the parallel and perpendicular components of a triplet line assigned to the delocalization of the uncoupled electron over an effective nuclear spin 1. It was suggested that this effective spin arises from the fast tunneling/rotation of a proton between two positions. The resonance spectra have been simulated with accuracy by using a simplified spin Hamiltonian and assuming Lorentzian-like resonance line shapes and axial asymmetry of the resonance line due to the trapping of free radicals in randomly oriented crystallites. The time evolution of free radicals in nitrogen atmosphere at room temperature has been analyzed. The decay kinetics of stable free radicals in 3-methyl nylon 3 (under inert atmosphere) has been investigated. It was shown that the radiation-induced radicals in inert atmosphere decay through a unimolecular reaction. (c) 2008 Elsevier B.V. All rights reserved.
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    ESR study of gamma irradiated 2-methyl nylon3
    (Pergamon-Elsevier Science Ltd, 2010) Çatıker, Efkan; Güven, Olgun; Özarslan, Özdemir; Chipara, Mircea
    Gamma radiation-induced radicals of 2-methyl nylon3 (2mN3) have been investigated by electron spin resonance spectrometry. The type of radicals generated, conversion into other radicalic species and their room temperature stability were evaluated. Two types of radicals have been detected. Two different formation mechanisms have been proposed for each radical. As suggested in literature for commercial polyamides, in our system we also observed two different radicals (R1 and R2). Among these radicals, R1 is expected to convert to R2, which is a chemically favorable process. (C) 2009 Elsevier Ltd. All rights reserved.
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    ESR study of gamma irradiated Nylon3
    (Pergamon-Elsevier Science Ltd, 2013) Çatıker, Efkan; Güven, Olgun; Özarslan, Özdemir; Chipara, Mircea
    Nylon3 (poly-beta-alanine) gamma irradiated in nitrogen was investigated by Electron Spin Resonance Spectroscopy to elucidate the type of radicals generated, their relative abundance, conversion into other radicalic species and their room temperature stability. Two types of radiation induced primary radicals have been detected. One of them (R-1) occurs by hydrogen abstraction from methylene group next to the carbonyl group, while the other (R-2) by hydrogen abstraction from methylene group next to amide group. R1 is observed to be converted into an alkoxy radical (R-3). Decay kinetics of the radicals in nitrogen was also examined and decay mechanisms have been proposed for each radical. (C) 2012 Elsevier Ltd. All rights reserved.
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    ESR study of poly($beta$-alanine) and its derivatives
    (2014) Çatıker, Efkan; Güven, Olgun; Özarslan, Özdemir; Chipara, Mircea
    Gamma radiation-induced radicals in poly(b-alanine), poly(a-methyl-$\\beta$-alanine) and poly(bmethyl-$\\beta$-alanine) have been investigated by Electron Spin Resonance Spectrometry technique. ESR spectra of polymers irradiated in nitrogen and air have been simulated by curve fitting software (Winsim2002). The type of radicals generated, their relative abundances, conversion into other radicalic species and their room temperature stability were evaluated. At least two types of radicals have been detected for each polymer. Most stable radicals have been obtained in the case of poly(a-methyl-b-alanine).