title: Periodic disorder along ramie cellulose microfibrils.
abstract: Small angle neutron scattering studies have been carried out on cellulose fibers from ramie and Populus maximowicii (cotton wood). Labile hydrogen atoms were replaced by deuterium atoms, in water-accessible disordered regions of the fibers, to increase the neutron scattering contrast between the disordered and crystalline regions. A meridional Bragg reflection, corresponding to a longitudinal periodicity of 150 nm, was observed when scattering collected from hydrogenated and deuterated dry ramie fibers was subtracted. No Bragg reflection was observed with the cotton wood fibers, probably because of lower orientation of the microfibrils in the cell wall. The ramie fibers were then subjected to electron microscopy, acid hydrolysis, gel permeation chromatography, and viscosity studies. The leveling off degree of polymerization (LODP) of the hydrolyzed samples matched exactly the periodicity observed in the diffraction studies. The weight loss related to the LODP was only about 1.5%, and thus, the microfibrils can be considered to have 4-5 disordered residues every 300 residues.
authors.affiliation: School of Agricultural and Life Science, The University of Tokyo, Tokyo 113-8657, Japan. nishiy@sbp.fp.a.u-tokyo.ac.jp
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Ung-Jin
authors.initials: UJ
authors.lastname: Kim
authors.forename: Dae-Young
authors.initials: DY
authors.lastname: Kim
authors.forename: Kyoko S
authors.initials: KS
authors.lastname: Katsumata
authors.forename: Roland P
authors.initials: RP
authors.lastname: May
authors.forename: Paul
authors.initials: P
authors.lastname: Langan
mesh_terms: D000143:Acids / Q000737:chemistry; D032402:Boehmeria / Q000737:chemistry* / Q000648:ultrastructure; D002473:Cell Wall / Q000737:chemistry / Q000648:ultrastructure; D002482:Cellulose / Q000737:chemistry* / Q000648:ultrastructure; D002850:Chromatography, Gel; D003903:Deuterium / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D020894:Microfibrils / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009502:Neutrons; D012542:Scattering, Radiation; D014783:Viscosity
chemical_list: D000143:Acids; D006859:Hydrogen; D002482:Cellulose; D003903:Deuterium