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  • 1985-1989  (2)
Collection
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of ornithology 129 (1988), S. 377-391 
    ISSN: 1439-0361
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 2
    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: Copolyetherurethan-Harnstoffe (PEUU) wurden in der Ionenquelle des Massenspektrometers mit einem linearen Temperaturprogramm pyrolysiert. Während der Aufheizung repetierend registrierte Massenspektren gestatten die Identifizierung und genaue Charakterisierung der untersuchten Polymeren.Die Bausteine der Makromolekeln: Polyether (Polyoxyethylen, Polyoxypropylen, Polyoxytetramethylen), 4,4′-Diisocyanatodicyclohexylmethan und das als Kettenverlängerer eingesetzte 4,4′-Diaminodiphenylmethan konnten anhand charakteristischer Fragmente („Schlüsselfragmente“) nachgewiesen werden.Darüber hinaus liefern sowohl die Polyether als auch die PEUU charakteristische Gesamtionenstromprofile. Die Einzelionenstromprofile von Schlüsselfragmenten zeigen, daß Harnstoff-, Urethan- und Etherbindungen in dieser Reihenfolge mit linear ansteigender Temperatur gespalten werden.
    Notes: Copoly(etherurethane-urea)s (PEUU) from different polyethers with hydroxyl endgroups, with 4,4′-diisocyanato-dicyclohexylmethane and 4,4′-diamino-diphenylmethane (as a chain extender) were heated linearly within the ion source of a mass spectrometer. The analysis of the evolved gases allows the identification and detailed characterization of the investigated polymers. The building units of PEUU  -  polyethers, diisocyanates, and the diamine  -  can be identified by key fragments. These are formed during pyrolysis and can be identified with field ionization or low-voltage electron impact ionization.Furthermore, the polyethers with hydroxyl endgroups as well as the PEUU can easily be distinguished by their volatilization rate curves. Fragments resulting from cleavages of the different bond types present, e.g., urea, urethane, ether in this order, are generated during the linear increase of temperature; they are pinpointed by repetitive scanning of the mass spectra.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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