Determination of diffusion coefficient of oxygen into polymers by using electron spin resonance spectroscopy. I. Poly(methyl methacrylate)

1989 ◽  
Vol 37 (9) ◽  
pp. 2577-2585 ◽  
Author(s):  
Yilmaz Kaptan ◽  
Önder Pekcan ◽  
Emin Arca ◽  
Olgun Güven
Keyword(s):  
Diffusion Coefficient ◽  
Electron Spin Resonance ◽  
Methyl Methacrylate ◽  
Electron Spin ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Poly Methyl Methacrylate ◽  
Spin Resonance ◽  
Diffusion Coefficient Of Oxygen

Determination of Thermal Histories of Archeological Cereal Grains with Electron Spin Resonance Spectroscopy

Science ◽  
1983 ◽  
Vol 222 (4629) ◽  
pp. 1235-1236 ◽  
Author(s):  
G. C. HILLMAN ◽  
G. V. ROBINS ◽  
D. ODUWOLE ◽  
K. D. SALES ◽  
D. A. C. MCNEIL
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Cereal Grains ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Spin Resonance ◽  
Thermal Histories

Determination of the Rates of Ring-Closure of Oxygen-Containing Analogs of Hex-5-Enyl Radical by Kinetic Electron Spin Resonance Spectroscopy

1987 ◽  
Vol 40 (1) ◽  
pp. 157 ◽  
Author(s):  
ALJ Beckwith ◽  
SA Glover
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Activation Parameters ◽  
Ring Closure ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Restricted Rotation ◽  
Conformational Effects ◽  
Spin Resonance

The hex-5-enyl (1), 3-oxahex-5-enyl (6), 2-oxahex-5-enyl (9) and 2,2-dimethylbut-3- enoyloxymethyl (13) radicals have been generated by interaction of the corresponding bromides with trialkyltin or trialkylgermanium radicals, and their rate constants and activation parameters for cyclization have been determined by kinetic e.s.r . spectroscopy. The 3-oxa species (6) undergo 1,5-ring closure more rapidly than does hex-5-enyl radical (1) because of favourable stereoelectronic factors. Spectral evidence has been obtained for restricted rotation about the O-CH2* bond in the 2-oxa radical (9) as a consequence of which its ring closure is relatively slow. Similarly, 1,5-ring closure of the ester derived radical (13) is slow because of unfavourable conformational effects arising from restricted rotation about the CO-O bond. The radical (22) formed from allyl bromoacetate does not undergo ring closure. Spectral data have been obtained for various radicals (16), (19), (23), (24) formed by intermolecular addition.

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