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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1175-1189 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Studies have been made of the γ-induced emulsion polymerization of styrene and comparisons made with chemically initiated emulsion polymerization. The polymerization proceeded smoothly to high conversions at 0 and 60°C, the reaction showing a high G (monomer) value. Complete conversions were obtained with total doses of less than 0.05 Mrad. In accordance with the behavior expected of systems having a constant rate of initiation, the molecular weight was found to decrease with decreasing temperature. The molecular weight and particle size distributions were narrower than those obtained in chemically initiated emulsion polymerizations at the same temperature. The radiation-induced emulsion polymerization of vinyl acetate proceeded smoothly at temperatures in the range 0-50°C to give polymers of much higher molecular weight than these obtained from chemically initiated polymerizations at the same temperature. Complete conversion was attained after a dose of 0.02 Mrad for latices approaching 50% solids. The elimination of ionic endgroups in the poly(vinyl acetate) radicals tends to drive the polymerization from the aqueous phase, resulting in faster rates and higher molecular weights than are obtained from chemically initiated systems. Rates of polymerization were found to be independent of temperature and the molecular weight of the polymer to be independent of dose rate. Latices of poly(vinyl acetate) of high solids content were evaluated for latex and film properties and found to have improvements over commercially available samples in both areas, especially in clarity of film and scrub resistance. A number of acrylate and maleate esters were copolymerized with vinyl acetate in a radiation-initiated emulsion system. High molecular weight copolymers were produced after low dose.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 143 (1971), S. 163-171 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Zusammensetzung von Terpolymeren aus Schwefeldioxid, konjugierten Dienen und Methacrylsäureestern, die mit SO2 keinen Komplex bilden können, wurde bestimmt. Wenn die Konzentration des dritten Monomeren im Reaktionsgemisch steigt, sollte der Gehalt an SO2 im Terpolymeren abnehmen. In einem weiten Gebiet der Zusammensetzungsverhältnisse wurde jedoch gefunden, daß der SO2-Gehalt ungefähr 50 Mol-% beträgt. Um dieses Ergebnis zu erklären, wurde ein Reaktionsmechanismus aufgestellt, durch den die Abweichung dieses Systems von den konventionellen Copolymerisationen erläutert wird. Die statistische Struktur dieser Terpolymeren wurde durch die Ergebnisse der thermogravimetrischen Analyse bewiesen. Die Terpolymerisation bewirkt eine kleine Erhöhung der thermischen Stabilität.
    Notes: The composition of terpolymers of sulfur dioxide, conjugated dienes and a methacrylate monomer which does not form a complex with sulfur dioxide should decrease in sulfur dioxide content as the concentration of the third monomer in the reaction mixture increases. The sulfur dioxide content of these terpolymers was actually nearly 50 mole-% over a wide range of reaction mixture compositions. A reaction route is presented by which the deviation of this system from conventional copolymerization behaviour is explained. A random structure of the terpolymers is deduced from the results of thermal gravimetric analysis of these polymers. A slight enhancement of thermal stability was obtained by terpolymerization.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 9 (1971), S. 1197-1202 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl methacrylate may be polymerized by free-radical initiators in liquid sulfur dioxide without incorporating sulfur dioxide in the polymer chain, even though methacrylate radicals and sulfur dioxide readily as indicated by electron spin resonance studies. An explanation for this anomalous result is advanced, and evidence for the participation of sulfur dioxide in the transition state of the addition reaction is presented.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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