A 13C solid-state NMR study of ion-exchange resins derived from natural polysaccharides

Several ion-exchange resins and resin precursor materials formed from natural polysaccharides have been examined by solid-state NMR spectroscopy. NMR spectra of the dry resin contained broad, featureless bands due to the polysaccharide backbone of the resin and additional broad bands due to attached groups. On addition of water to the resin, the resonances for the polysaccharide backbone remained broad, but those due to the attached groups were considerably sharpened. Many individual resonances of the attached groups could thus be assigned, so that changes brought about by chemical modification of the polysaccharide during the production of an ion-exchange resin could be followed