The NMR spectra of a series of compounds were taken in order to identify the nitrogencontaining linkages which had been considered to be present in polyurethane elastomers. It has been found that the urea, the urethane, the allophanate and t h e biuret can be discriminated each other by their different chemical shifts when the measurement is made in polar solvent like N,N-dimethyl acetamide, dimethyl sulfoxide, etc. The method was further applied to the analysis of the uncured linear prepolymer prepared from polypropylene glycol and diphenylmethane-4,4'-diisocyanate or tolylene diisocyanate.
ZUSAMMENFASSUNG:Die NMR-Spektren einer Reihe von Modellverbindungen wurden untersucht zur Identifizierung der stickstoffhaltigen Bindungen, die in den Elastomeren des Polyurethantyps anzunehmen sind. Es ergab sich, daR Harns'toffe, Urethane, Allophanate und Biurete durch ihre verschiedene chemische Verschiebung unterschieden werden konnen, wenn die Messung in polaren Losungsmitteln wie Dimethylacetamid, Dimethylsulfoxyd u. a. durchgefiihrt wird. Die Methode wurde ferner fiir die Analyse von linearen Prepolymerisaten aus Polypropylenglycol und Diphenylmethan-4,4'-diisocyanat oder Tolylendiisocyanat angewandt.
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