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  • Chemistry  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 58 (1962), S. 1243-1252 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The following possibilities of introducing hydroxyl endgroups in polymers have been experimentally realized: (1) redox initiation by ferrous sulfate + H2O2 (Fenton's reagent), N2H4, H2O + H2O2, FeCl3 + H2O2; photoinitiation by Fe(OH)++ + light, H2O2 + ultraviolet light or sunlight, and initiation by unstable Ag+++ complex in dark; (2) copolymerization with a trace of allyl alcohol or with traces of vinyl acetate and allyl acetate and subsequent hydrolysis; (3) chain transfer with butyl alcohols. The method of detection consists in first converting hydroxyl endgroups to carboxyl endgroups by refluxing with phthalic anhydride or 3-nitrophthalic anhydride in benzene and pyridine medium or with maleic anhydride in benzene medium and testing the resulting polymer for carboxyl endgroup by the dye-interaction test with rhodamine 6GX dye extract. The hydroxyl endgroup was also quickly converted to a strong acid endgroup like OSO3H by reacting the polymer with chlorosulfonic acid in chloroform medium under controlled conditions and tested by the dye-interaction test or a dye-partition test with methylene blue. This test is not entirely satisfactory, as the reagent attacks the thermal polymers slightly.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 2 (1964), S. 4433-4440 
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Quantitative determination of endgroups of poly(methyl methacrylate), polystyrene and poly(vinyl acetate) obtained by aqueous initiation with K2S2O8 under varied conditions have been made by the application of two sensitive dye techniques, called the dye partition technique and the dye interaction technique. The description of the dye techniques are given in detail. Sulfate (OSO3-) and hydroxyl (OH) endgroups are generally found to be incorporated in the polymers to an average total of 1.5 to 2.5 endgroups per polymer chain. Hydroxyl endgroups are always present to a fairly large extent. The proportion of sulfate endgroups in polymers is highly dependent on the pH of the polymerizing medium; it increases with the alkalinity of the medium and sharply decreases under acid conditions.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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