A CP/MAS C-13 NMR investigation of molecular ordering in celluloses

The individual states of order of cellulose found within Valonia, Cladophora, Halocynthia, cotton and wood cellulose were quantified by non-linear least-squares fitting of the C-13 NMR spectra. The results from the spectral fittings indicated that a cellulose form giving signals at delta 104.5 (C-1 region) and delta 88.1-88.5 (C-4 region) was present in all the investigated samples. Partial signal suppression by spin-lattice relaxation supported the findings from the spectral fittings. The spectral behavior of this cellulose form indicates it is a less-ordered or a para-crystalline 'in core' structure with a somewhat larger mobility than the crystalline cellulose I alpha and I beta allomorphs. (C) 1997 Elsevier Science Ltd.