Nuclear magnetic resonance studies of ionomers. 6. Polyurethane‐polyphosphonate blends

Blending of a poly(ether urethane) with a polyphosphonate obtained by phase transfer catalyzed polycondensation of 4,4′‐biphenol and chloromethylphosphonic dichloride generates a phase‐separated material. One phase contains the soft segment of the polyurethane. This has been excluded from a high‐Tg phase that contains ionic species formed mainly by proton transfer and elimination reactions between the hard segment of the polyurethane and the polyphosphonate. Two glass transitions appear in the blend: one close to the Tg of the polyphosphonate and one belonging to the excluded soft segment of the polyurethane. The low temperature Tg decreases with the increasing content of the polyphosphonate, whereas the high temperature transition increases slightly, indicating an increasing purity of the soft segment and the presence of ionic interactions in the hard segment. The presence of ionic interactions is confirmed by NMR analysis of the blend. Comparison of the spectra of the blends with those of the pure components, along with two‐dimensional experiments, indicate a reaction involving the chloromethyl groups of the polyphosphonate and the nitrogens of the polyurethane.