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  • 1985-1989  (4)
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Year
  • 1
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    Unknown
    The thermal dissociation of water: The forgotten literature (1986)
    American Chemical Society
    Details
    Publication Date: 1986-12-01
    Print ISSN: 0021-9584
    Electronic ISSN: 1938-1328
    Topics: Chemistry and Pharmacology , Education
    Published by American Chemical Society
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    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Evolution of H2O and CO2 during the copper-catalyzed oxidation of isotactic polypropylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 389-403 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics and mechanism of H2O and CO2 evolution during uncatalyzed and copper(oxide)-catalyzed (Cu, CuO, CuO0.67) oxidation of isotactic polypropylene have been investigated in detail for various catalysts over a range of temperatures (90-150°C). These volatiles were determined chromatographically; H2O and CO2 represent the main volatiles of the oxidation, comprising about 80 mol % of all volatiles. Uncatalyzed oxidation evolves ca. 1 mol of H2O and 1 mol of CO2 for each unit mole of polymer oxidized, while catalyzed oxidation produces 2 mol of H2O and ca. 1.2 mol of CO2 for each unit mole of polymer. These results indicate that secondary as well as tertiary H atoms on the polymer chains are involved in hydroperoxide formation and decay. The oxidation mechanism has been formulated and evaluated on this basis. It consists essentially of two parallel oxidation reactions involving tertiary and secondary groups (H atoms and hydroperoxides), respectively. The mechanism can be represented by first- and pseudo-first-order reactions in series: (1) oxygen absorption showing induction periods; (2) hydroperoxide formation and decay (plateaus are reached); (3) H2O evolution from the decay of hydroperoxides; and (4) subsequent CO2 production involving chain scission. Arrhenius parameters for all oxidation reactions (uncatalyzed and catalyzed) are also presented. It appears that CuO0.67 is the most efficient catalyst of those investigated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240301
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Diffusion of Cu2+ catalysts from Cu-metal polymer or Cu-oxide/polymer interfaces into isotactic polypropylene (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 503-510 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diffusion coefficients of Cu2+ in the form of its carboxylate have been measured in isotactic polypropylene as a function of temperature (90-128°C) and extent of preoxidation. Diffusion take place from the metal catalyst/polymer interface into the bulk polymer. The diffusion is dependent on the extent of preoxidation and temperature but not on the type of catalyst (Cu, CuO, CuO0.67). Analysis of polymer sections for Cu2+ ions was carried out with a selective Cu2+ electrode. Diffusion in isotactic polypropylene is about 1000 times faster than in lowdensity polyethylene. The carboxylate anion appears to have about 7 C-atoms for diffusion in isotactic polypropylene compared with 29 C-atoms for low-density polyethylene.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1986.090240303
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrogen peroxide determination by I.R. specular reflectance spectroscopy during uncatalyzed and copper (oxides)-catalyzed oxidation of isotactic polypropyleneWork supported by USDCOE under Contract No. EG-77-C-021-01-4042. (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 23 (1985), S. 2291-2304 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: IR specular reflectance spectra with respect to hydrogen peroxide formation during uncatalyzed and Cu (oxide)-catalyzed oxidation of isotactic Polypropylene films have been measured as function of time and temperature (90-130°C). Energies of activation for the various cases have been obtained. The originally proposed kinetic scheme based on oxygen-absorption measurements has been modified in order to accommodate the spectroscopical results. The amount of ROOH groups present at any time on the polymer is very small, indicating relatively slow rates of ROOH formation and fast rates of their decomposition. The kinetic scheme fits well the experimental data. However, the reasons for the variations of the relevant energies of activation obtained for the catalyzed oxidation in absence and presence of the main volatile reaction products, H2O and CO2, are not yet understood, i.e., the mechanism needs further investigations.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.170230818
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