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  • 1
    Electronic Resource
    Electronic Resource
    Diffuse Reflectance Spectrophotometry in Ultraviolet Using Powdered Salts (1959)
    s.l. : American Chemical Society
    Analytical chemistry 31 (1959), S. 1338-1341 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60152a027
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Detection of Free Radicals in Polyacrylonitrile by Paramagnetic Resonance (1955)
    [s.l.] : Nature Publishing Group
    Nature 175 (1955), S. 894-895 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Acrylonitrile was polymerized photochemically in a tube of J in. diameter with di-iert.-butyl peroxide (10 per cent v/v) as catalyst. The rate was 7 x 10~3 mol.lit.-1 sec.-1. After 20 per cent conversion the unchanged monomer and catalyst were distilled off in vacuum and the tube sealed. The ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/175894b0
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  • 3
    Electronic Resource
    Electronic Resource
    Spectroscopy of aqueous solutions: protein and DNA interactions with water (2000)
    Springer
    Cellular and molecular life sciences 57 (2000), S. 999-1007 
    Details
    ISSN: 1420-9071
    Keywords: Key words. Infrared (IR) and near-infrared (NIR) spectroscopy; electron paramagnetic resonance (EPR) spectroscopy; water; aqueous solutions; biomolecules.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. This review emphasises the need to use spectroscopy in order to understand the behaviour of water, and summarises the background of the subject. The various forms of spectroscopy that are especially informative are described, with particular reference to near-infrared (NIR) spectrophotometry. The key results are outlined, first those obtained with small molecules and ions, and second those involving proteins, DNA and cell membranes. Finally, some interpretations are offered which include the novel but possibly controversial concept of free OH and free lone-pair groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00000753
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  • 4
    Electronic Resource
    Electronic Resource
    Trapped radicals in heterogeneous vinyl polymerization (1959)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 34 (1959), S. 181-198 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The existence of trapped radicals in polymers prepared heterogeneously from vinyl monomers was first deduced from kinetic observations and subsequently confirmed by electron resonance spectroscopy. We have used this latter technique to determine the concentration of trapped polyacrylonitrile radicals obtained as a function of the experimental variables including the degree of swelling of the polymer, the rate of photo-initiation and the temperature of polymerization. In the bulk polymerization of acrylonitrile at 25°C. the fraction of radicals which become trapped is approximately 12% for a conversion of 17%. The concentration of trapped radicals obtained in the presence of N,N-dimethylformamide increases for low concentrations of the swelling agent, passes through a maximum, and subsequently decreases to zero. Qualitatively similar behavior is obtained if the swelling of the polymer is increased by the incorporation of methyl acrylate as commonomer. Addition of a swelling agent to the active photopolymer leads to destruction of the radicals. An increase in the concentration of trapped radicals with increasing light intensity (for a given conversion) is observed initially; at very high intensities the concentration decreases to zero. There is a marked decrease in the concentration of radical as the temperatur of polymerization increase; it is doubtful if trapping occurs significantly at 60°C. There observations are discussed in terms of previous kinetic studies and shown to be in general accord with the occlusion theory of heterogeneous polymerization. The effect of oxygen on the electron-resonance absorption is characterized by a rapid initial decrease followed by a slow decay. The results are tentatively interpreted in terms of the formation of peroxy and/or HO2 radicals. It is surprising that the absorption line obtained with polyacrylonitrile radicals does not show the fine structure which would be expected to arise from interaction of the unpaired electrons with hydrogen and nitrogen nuclei. A possible reason for this is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1959.1203412716
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