Assignment of non-crystalline forms in cellulose I by CP/MAS 13C NMR spectroscopy

Non-crystalline forms of cellulose in birch pulp, cotton linters and Cladophora sp were studied by CP/MAS 13C NMR spectroscopy. New assignments were made for the NMR-signals in the lower shift part of the C-4 region (80–86 ppm). These signals were assigned to cellulose at accessible fibril surfaces, cellulose at inaccessible fibril surfaces and hemicellulose. Also, further evidence was found for para-crystalline cellulose as an “in-fibril” form, inaccessible to the surrounding solvent.