High resolution neutron fibre diffraction data on hydrogenated and deuterated cellulose

High-resolution fibre neutron diffraction data were recorded from cellulose samples on a D19 diffractometer at the Institut Laue-Langevin (Grenoble). Highly crystalline cellulose I samples from Cladophora (cellulose I alpha I beta) or Halocynthia (cellulose IF) origin were prepared in the form of oriented films. Samples were studied in a hydrogenated form and in a hydrog en-deuterium exchanged deuterated form corresponding to all OH moieties bei ng replaced by ODs. These samples, which diffracted to a resolution of arou nd 0.9 Angstrom, save diffraction diagrams consisting of several hundred in dependent diffraction spots. Crystalline cellulose II fibres resulting from the mercerization of flax were also studied in a hydrogenated form using N aOH/H2O as mercerizing medium and in a deuterated form using NaOD/D2O. Both of these samples diffracted to around 1.2 Angstrom, giving fibre diffracti on diagrams slightly less reserved than those of cellulose I, but still con sisting of more than one hundred independent diffraction spots. For cellulo se I as well as for cellulose II, significant differences between the hydro genated and deuterated patterns were observed and recorded. These new data should lead to improved structures for cellulose and direct identification of the position of hydrogen atoms involved in hydrogen bonding. (C) 1999 El sevier Science B.V. All rights reserved.