Investigation of the Phase Separation Behavior of Polyurethane Elastomers by Two-Dimensional Wide-Line-Separation Nuclear Magnetic Resonance Spectroscopy

摘要

Several methods associated with solid-state NMR have been used to investigate thephase separation behavior of polyurethane elastomers. The recently developed two-dimensional wide-line-separation nuclear magnetic resonance spectroscopy (WISE-NMR) provides a particularly interesting alternative tool for determination of the phase composition of polyurethane elastomers. With this experiment, a correlation has been established between chemical structure and segmental mobility as reflected in (13)C chemical shifts and (1)H line shapes, respectively. Segments dispersed in the hard-segment-rich domain are immobilized, resulting in broad components in the (1)H spectra. The fraction of hard/soft segments distributed in each phase can therefore be calculated from the resolved (13)C spectrum. Utilizing this technique, the degree of phase separation in piperazine-based polyurethanes has been established. p3.