HYDROGEN-BONDING IN COPOLY(ETHER-UREA)S AND ITS RELATIONSHIP WITH THEPHYSICAL-PROPERTIES

The evolution of hydrogen bonding with temperature in three copoly(eth er-urea)s with no phase separation has been studied by Fourier transfo rm infrared spectroscopy (FT-IR) in the region of the carbonyl absorpt ion of the urea groups. Assignment of the bands was made by supposing the existence of chains of urea groups linked by bifurcated hydrogen b onds. Quantum mechanical calculations of these chains fitted qualitati vely with the experimental results. Dynamic mechanical and calorimetri c experiments showed that the apparition of the band related to the '' internal'' urea groups of the chains produces a decrease in the glass transition of the polyether moiety of the copolymer and that prior to it a transition that we related to the glass transition of the bis(ure aphenyl)methane units takes place.