scholarly journals The Decay of Irradiation Defects in Polymethyl Methacrylate

1962 ◽  
Vol 15 (4) ◽  
pp. 652 ◽  
Author(s):  
ID Campbell ◽  
FD Looney
Keyword(s):  
Electron Spin Resonance ◽  
Polymethyl Methacrylate ◽  
Electron Spin ◽  
Room Temperature ◽  
Γ Irradiation ◽  
Radical Species ◽  
Decay Mechanism ◽  
Spin Resonance ◽  
Chemical Groups

The decay of defects in polymethyl methacrylate caused by γ-irradiation has been followed by electron-spin resonance. The samples were irradiated at room temperature and annealed at 80, 90, and 100 �C. Two radical species can be recognized by their different modes of decay. Some attempt is made to identify the chemical groups involved and to explain the decay mechanism.

Free radicals in γ-irradiated disodium succinate. Part 1. Monoclinic crystals

1970 ◽  
Vol 48 (18) ◽  
pp. 2804-2808 ◽  
Author(s):  
H. M. Vyas ◽  
J. Janecka ◽  
M. Fujimoto
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Succinic Acid ◽  
Electron Spin ◽  
Room Temperature ◽  
Γ Irradiation ◽  
Stable Conformation ◽  
Spin Resonance ◽  
Radiation Processes ◽  
Disodium Succinate

Crystals of disodium succinate have two distinct modifications, monoclinic and triclinic. These were recognized by electron spin resonance (e.s.r.) studies of. the free radicals produced by γ-irradiation. In the monoclinic crystals, e.s.r. spectra and radiation processes appear similar to those observed in γ- (or x-) irradiated succinic acid. The situation in triclinic crystals is more complex (see Part 2). In monoclinic crystals irradiated at 77 °K, two types of radical coexist. They were identified as −O2CCH2CH2ĊO22−, 1, together with a distorted conformation of the radical −O2C(ĊHCH2)*CO2−, 2. On warming to room temperature the former species disappears while the latter changes irreversibly to a stable conformation −O2CĊHCH2CO2−, 3.

scholarly journals Force detection of high-frequency electron spin resonance near room temperature using high-power millimeter-wave source gyrotron

2021 ◽  
Vol 118 (2) ◽  
pp. 022407
Author(s):  
Hideyuki Takahashi ◽  
Yuya Ishikawa ◽  
Tsubasa Okamoto ◽  
Daiki Hachiya ◽  
Kazuki Dono ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Millimeter Wave ◽  
Electron Spin ◽  
High Power ◽  
High Frequency ◽  
Room Temperature ◽  
Force Detection ◽  
Wave Source ◽  
Spin Resonance ◽  
Millimeter Wave Source

Radiation damage in polyethylene as studied by electron spin resonance

1961 ◽  
Vol 262 (1309) ◽  
pp. 207-218 ◽  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Alkyl Radical ◽  
Room Temperature ◽  
Chemical Properties ◽  
Resonance Method ◽  
Alkyl Radicals ◽  
Spin Resonance ◽  
Physical And Chemical ◽  
Kinetics Of

The electron spin resonance method was employed to study the nature, concentration and kinetics of the disappearance under varying conditions of radicals produced in polyethylene by fast electron irradiation at 77°K. The predominant radical species at 77°K is the alkyl radical —CH 2 —ĊH—CH 2 —. On being warmed to room temperature it disappears rapidly, revealing a more stable un­identified radical. The kinetics of the decay at room temperature of both radicals was observed. Their stabilities were found to vary in polyethylene samples of differing physical and chemical properties. G values for these radicals are given. Comparison was made with spectra obtained under similar conditions with two pure paraffins and a pure olefin to evaluate the effect of crystallinity branching, molecular weight and unsaturation. In the olefin there is evidence for a build-up of allyl radicals due to the encounter of an alkyl radical with main chain unsaturation. This supports the view that alkyl radicals are mobile, and cross-linking occurs when two such radicals meet.

Electron spin resonance study of SO2 and CO on CuO–alumina

1982 ◽  
Vol 60 (18) ◽  
pp. 2340-2341 ◽  
Author(s):  
K. C. Khulbe ◽  
R. S. Mann
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Electron Spin Resonance Study ◽  
Alumina Catalyst ◽  
Treated Sample ◽  
Spin Resonance ◽  
Spin Resonance Study

The intensity of the Cu2+ esr signal increased significantly on the addition of CO or SO2, especially with SO2, at room temperature to the preheated (at 400 °C) and evacuated CuO–alumina catalyst. When the CO or SO2 treated sample was evacuated at room temperature, the shape and intensity of the Cu2+ esr line returned to their original values. The intensity of the Cu2+ esr line decreased, but not to zero, on heating CuO–alumina either with CO or SO2. In the case of SO2, a new line appeared for the [Formula: see text] ion which was not affected on evacuation. It seems that the [Formula: see text] do not take part in the reduction of SO2 with CO over the CuO–alumina catalyst.

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