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  • 1
    Electronic Resource
    Electronic Resource
    Postirradiation polymerization and ESR studies of γ-irradiated N-tert-butylacrylamide (1983)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 184 (1983), S. 1919-1926 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Postirradiation polymerization of γ-irradiated N-tert-butylacrylamide was studied at 80, 85, 90, and 100°C, and the activation energy was found to be 183 kJ · mol-1. By ESR spectroscopy, the half-life for the second order decay of the irradiated monomer was found to be 13,8 h at 25°C with a decay rate constant of 4,5 · 106 g · mol-1 · h-1. The effect of oxygen and sulfur dioxide on γ-irradiated N-tert-butylacrylamide was also studied. It was observed that oxygen reacts with N-tert-butylacrylamide free radicals resulting in a characteristic peroxyl radical spectrum. The signal decays rapidly and disappears in about 100 h. The decay was found to be of second order with a rate constant of 1,3 · 107 g · mol-1 · h-1 and a half-life of 3,8 h at 25°C. In contrast to the situation with atmospheric oxygen, an appreciable fraction of the free radicals does not react rapidly with sulfur dioxide. The changes in the ESR spectra indicate that at least a large fraction of the original N-tert-butylacrylamide radicals, generated in the irradiated sample, react with sulfur dioxide rapidly to give sulfonyl radicals. Their decay is second order with a rate constant of 4,5 · 106 g · mol-1 · h-1 and a half-life of 8,3 h.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1983.021840918
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  • 2
    Electronic Resource
    Electronic Resource
    ESR studies of some γ-irradiated organic crystals (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 19 (1981), S. 3047-3061 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acrylamide, N-tert-butylacrylamide, and propionamide crystals were irradiated at -196°C and the structures of radicals studied by ESR spectroscopy at various temperatures. The γ-irradiated acrylamide crystals show a five-line spectrum which is similar in shape to the signal obtained from the γ-irradiated propionamide crystals. Two types of radicals are produced in irradiated acrylamide and propionamide crystals at -196°C. When the irradiated samples are kept at -78°C the spectrum of propionamide remains the same, except in intensity. In contrast to this, the acrylamide spectrum changes to a triplet because of dimerization. Upon warming the irradiated acrylamide sample to between -50 and -30°C, some small new peaks become apparent on either side of the triplet. These new peaks disappear above -20°C and the spectrum changes to a triplet because of polymerization. To observe the changes in the ESR spectra of γ-irradiated N-tert-butylacrylamide we kept the sample at various temperatures from -196 to 100°C. From -196°C to about room temperature the spectrum is a quintet. At and above 35°C, the spectrum changes to a triplet with shoulders on either side of the main peaks. With further warming above 80°C the spectrum changes to a broad triplet.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.170191202
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal and radiation-induced polymerizations of N-tert-butylacrylamide and (N-tert-butylacrylamide)2-ZnCl2 complex (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 453-462 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal and radiation-induced in-source and postirradiation polymerizations of N-tert-butylacrylamide and (N-tert-butylacrylamide)2-ZnCl2 complex of this monomer were studied at various temperatures. In in-source, solid-state polymerizations of monomer and complex the conversion was about 95% at 21°C in about eight days. Their postirradiation polymerizations were also studied in solid state. The conversion-time curves of these two systems show an autoacceleration as in-source polymerization. In both types of polymerization the overall rate of polymerization of complex was higher than that of pure monomer at the same polymerization temperature. In investigations of the thermal polymerization of N-tert-butylacrylamide and ZnCl2-complex it was observed that the ZnCl2-complex system can be polymerized in air in the molten and solid state. The conversion of monomer to polymer reaches limiting values in solid state in about 1 hr. The thermal polymerization of ZnCl2-complex in the molten state was also studied and 100% conversion was obtained in 30 min. The thermal polymerization of pure monomer was studied in vacuum and an appreciable amount of polymer was obtained in the molten state; however, the thermal polymerization of this monomer is negligible in solid state. In this work rates of polymerization for N-tert-butylacrylamide and (N-tert-butylacrylamide)2-ZnCl2 are compared under various experimental conditions and overall activation energies are calculated.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220216
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  • 4
    Electronic Resource
    Electronic Resource
    Thermal polymerization of N-tert-butylacrylamide in 1,4-dioxane (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 23 (1985), S. 1017-1029 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the thermal polymerization of N-tert-butylacrylamide were investigated in 1,4-dioxane as solvent, in the 65-80°C temperature range. It was found that the overall rate of polymerization which was determined by a gravimetric method is proportional to the 1.9 power of monomer concentration at 70°C. The rate of initiation was determined by ESR spectroscopy using DPPH as an inhibitor, and it was found that the order of initiation rate is 1.8 with respect to monomer concentration at 70°C. The overall activation energy for the thermal polymerization of N-tert-butylacrylamide was found to be 64 ± 9 kJ mol-1 in the 65-80°C temperature range. The activation energy for the rate of initiation was also determined and it was found to be 90 ± 23 kJ mol-1.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.170230407
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