38—NUCLEAR MAGNETIC RESONANCE OF WATER SORBED ON FIBROUS MATERIALS

Abstract

The sorption of water in wool, silk and nylon fibres, and in wool cortical cells, has been studied by nuclear magnetic resonance (NMR). Proton resonance line shapes and relaxation times were determined as a function of moisture content. In every case the relatively narrow signal from the sorbed water could be distinguished from the broad resonance of the substrate. As little as I% water in wool can be detected by this technique. The width of the resonance depends on both the sorbent and the moisture content and decreases as the moisture content is increased as a result of the increasing mobility of the sorbed water. The results of this study, when interpreted in terms of the Kubo-Tomita theory of magnetic resonance and the kinetic theory of rate processes, suggest that the water is bound in clusters to the sorbent, and that surface migration is the dominant mode of magnetic relaxation.