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  • 1
    Electronic Resource
    Electronic Resource
    Oxygen-ascorbic acid-ferric ion initiating system. Kinetics of polymerization of methyl methacrylate (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 115 (1983), S. 61-74 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde die Kinetik der Polymerisation von Methylmethacrylat in verdünntem salpetersaurem Medium bei 40°C mit einem Dreikomponenteninitiator  -  Saurestoff-Ascorbinsäure-Fe3+ionen  -  untersucht. Die Polymerisationsgeschwindigkeit, Rp, erwies sich bei unterschiedlichen experimentellen Bedingungen proportional [MMA]1,5. Rp war unabhängig von der [Fe3+] innerhalb der Konzentrationsreihe 2-5·10-5M, erniedrigte sich aber bei höheren Werten. Rp war auch unabhängig von der [AA] und für [O2] 〈 6,5·10-4M wurde eine Abhängigkeit [O2]0,6 gefunden.
    Notes: The kinetics of polymerization of methyl methacrylate (MMA) in dilute nitric acid medium at 40°C initiated by the three component initiating system, oxygen-ascorbic acid (AA)-ferric ions was investigated. The rate of polymerization, Rp, was found to be proportional to [MMA]1.5 under different experimental conditions. Rp, was independent of [Fe3+] in the concentration range 2 to 5 - 10-5 M, but decreased slightly at higher values. Rp was also independent of [AA] and a dependence on [O2]0.6 was noticed with [O2] 〈 6.5 × 10-4M. After an initial increase, Rp became independent above [HNO3] ≈ 0.3M. Ionic strength, μ, of the medium had no effect on Rp. A rate increase up to 42°C followed by constancy and decrease with further increase in temperature (〉46°C) was noticed. The chain lengths of the polymers were determined to be in the range 102  -  103 by viscometry. A plausible reaction mechanism with initiation by the primary radical and termination by mutual interaction was proposed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1983.051150106
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  • 2
    Electronic Resource
    Electronic Resource
    Oxygen-ascorbic acid-Copper(II) initiating system. A kinetic study of the polymerisation of methyl acrylate in aqueous medium (1982)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 905-913 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerisation of methyl acrylate (MA) initiated by O2-ascorbic acid (AA)-Cu2+ system was studied in aqueous medium at 40°C. The rate of polymerisation Rp, was found to increase, remain constant, and then decrease with increasing [Cu2+]. Rp was found to depend on [Cu2+]0,6, [AA]0, [O2]0,6, and [MA]1,3 in the increasing region, on [Cu2+]0, [AA]0, [O2]0,6, and [MA]1,6 in the constant region and on [Cu2+]-0,9, [AA]0, [O2]0,7, and [MA]2,0 in the decreasing region. Rate laws were derived assuming a plausible reaction mechanism for the different regions. Rp increased with ionic strength and decreased with [H2SO4,]. An initial increase, then steady state followed by a decrease in rate with temperature was noticed in the range 25 - 55°C. kp/kt1/2 values were calculated and compared with literature values. Chain lengths were determined viscometrically.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1982.021830414
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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