NMR STUDIES ON POLYETHER-POLYURETHANE ZWITTERIONOMERS——CHAIN STRUCTURE AND PHASE SEPARATION

The ~1H and ~(13)C NMR spectra of polyether-polyurethancs (A) based on 4, 4'-diphenylmethanediisocyanate (MDI), N-methyl diethanolamine (MDEA), and polytetramethyleneoxide (PTMO)and the zwitterionomers derived from A with various degree of ionization was assigned by comparingwith model compounds. Phase separation of the samples was visualized through pulsed NMR investigations. The FIDsignals of these multiphase elastomers were recorded and decomposed by non-linear least squaresregression into fast Gaussian and slow exponential components assodated with the hard, the soft andthe interface respectively. Thus pulsed NMR gives both qualitative and quantitative informationabout the existence of multiphases and the relative amounts of materials in each phase.

NMR STUDIES ON POLYETHER-POLYURETHANE ZWITTERIONOMERS——CHAIN STRUCTURE AND PHASE SEPARATION

 The ¹H and ¹³C NMR spectra of polyether-polyurethancs (A) based on 4, 4'-diphenylmethanediisocyanate (MDI), N-methyl diethanolamine (MDEA), and polytetramethyleneoxide (PTMO)and the zwitterionomers derived from A with various degree of ionization was assigned by comparingwith model compounds. Phase separation of the samples was visualized through pulsed NMR investigations. The FID signals of these multiphase elastomers were recorded and decomposed by non-linear least squaresregression into fast Gaussian and slow exponential components associated with the hard,the soft and the interface respectively.Thus pulsed NMR gives both qualitative and quantitative information about the existence of multiphases and the relative amounts of materials in each phase.