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  • 1950-1954  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Friedel-Crafts polymerizations. III. Medium effects in the Friedel-Crafts polymerization of styrene (1951)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 6 (1951), S. 725-732 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In polymerizing styrene at room temperature in the presence of tin tetrachloride, it is found that the rate of polymerization is greatly affected by the dielectric constant of the medium. It increases by a factor of approximately 1400 when the dielectric constant changes from 6.5 to 18.4. At the same time the degree of polymerization increases only slightly. The results are interpreted as supporting evidence for the mechanism of Friedel-Crafts polymerizations as suggested by Polanyi and co-workers. A unimolecular termination by proton-splitting cannot be reconciled with these results.Quantitative equations are derived relating the rate and degree of polymerization to the dielectric constant. Traces of liquid water have no visible effect on the polymerization while larger amounts cause retardation. The degree of polymerization, which is of the order of 20, does not change with conversion and is unaffected by the catalyst present.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1951.120060607
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  • 2
    Electronic Resource
    Electronic Resource
    A color reaction involving vinyl chloride containing polymers and pyridinePresented before the Division of Polymer Chemistry at the 122nd meeting of the American Chemical Society; Atlantic City, New Jersey, September, 1952. (1953)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 11 (1953), S. 233-242 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When a dilute pyridine solution of vinyl chloride polymers or copolymers is heated and a few drops of alcoholic hydroxide are added to the hot solution, a dark brown color develops. The response of vinyl chloride polymers in this reaction is much more intense than that of most other organic compounds, probably due to the conjugated double bonds produced in the main chain through the loss of hydrogen chloride. In addition to straight degradation of the polymer, the formation of an isocyanine dye is suggested by a mechanism which, besides pyridine and the polymer, involves the alkali alkoxide as a reactant.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1953.120110306
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    Paper (German National Licenses)
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