Molecular mobility in wool fibers as determined from nuclear magnetic resonance studies

The mobility of protons in wool samples of Lincoln, Chokla, and Merino, equilibrated to various moisture contents in the range of 0–98% relative humidity (RH), have been studied by pulsed nuclear magnetic resonance (NMR) technique. Peak height and peak width were determined from absorption and derivative curves and the relaxation times T₁ and T₂ were determined from relaxation curves. The mobility increases with increase in moisture content. Among the three wools, the mobility was high in Merino as compared to the other two wools. The differences in the measured mobilities were related to structural and morphological differences in the three wools. The present analysis suggests that water in wool has at least three different associations, each with a different binding energy.