Radiation-induced, solid-state polymerization of derivatives of methacrylic acid. IX. Electron spin resonance and product analysis study of the gamma radiolysis of methacrylic acid, barium methacrylate and their saturated analogues, isobutyric acid and ba

O'Donnell J.H. and Sothman R.D. (1979) Radiation-induced, solid-state polymerization of derivatives of methacrylic acid. IX. Electron spin resonance and product analysis study of the gamma radiolysis of methacrylic acid, barium methacrylate and their saturated analogues, isobutyric acid and barium isobutyrate. Radiation Physics and Chemistry, 13 3-4: 77-88. doi:10.1016/0146-5724(79)90053-0


Author O'Donnell J.H.
Sothman R.D.
Title Radiation-induced, solid-state polymerization of derivatives of methacrylic acid. IX. Electron spin resonance and product analysis study of the gamma radiolysis of methacrylic acid, barium methacrylate and their saturated analogues, isobutyric acid and barium isobutyrate
Journal name Radiation Physics and Chemistry
ISSN 0146-5724
Publication date 1979
Sub-type Article (original research)
DOI 10.1016/0146-5724(79)90053-0
Volume 13
Issue 3-4
Start page 77
End page 88
Total pages 12
Subject 3108 Radiation
Abstract Methacrylic acid and barium methacrylate polymerize in the solid state during and after gamma irradiation. Previous ESR studies have indicated a free radical chain mechanism initiated by radical, particularly H atom, addition to the C=C bond. The radiation chemical yields of small molecular products are now reported and correlated with the ESR spectra and yields of molecular products from the saturated analogues, isobutyric acid and barium isobutyrate, in order to provide a detailed mechanism for the radiolysis. The ESR spectrum of barium isobutyrate at -196°C was similar to that of isobutyric acid and is attributed to (i) isobutyrate radical CH3-Ċ(CH3)COO-; (ii) isobutyrate anion radical [CH3-CH(CH3)COO-]-; and (iii) isopropyl radical CH3-Ċ(CH3)H. Conversion of radicals (ii) and (iii) into (i) occurred on warming and second-order decay of (i) was measured at higher temperatures. For isobutyric acid irradiated at 0°C, G(CO2)=5.4, which is compatible with values for n-carboxylic acids, but in marked disagreement with G(CO2)=14.4 for isobutyric acid reported by Johnsen.(11) Water was proven to be a significant radiolysis product. CO2 was the major product from methacrylic acid and barium methacrylate, but in lower yields than from the isobutyrates; the other products were propyne, hydrogen, water, propylene, carbon monoxide and methane, all in relatively low yield.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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