title: Hydration properties of regioselectively etherified celluloses monitored by 2H and 13C solid-state MAS NMR spectroscopy.
abstract: The hydration properties of 2,3-O-hydroxypropylcellulose (HPC) and 2,3-O-hydroxyethylcellulose (HEC) were analyzed by multi-nuclear solid-state MAS NMR spectroscopy. By 13C single-pulse (SP) MAS and cross-polarization (CP) MAS NMR, differences between the immobile regions and all parts of the polysaccharides were detected as a function of hydration. Complementary information about the water environments was observed by 2H MAS NMR. By this approach it was demonstrated that side chains in 2,3-O-HPC and 2,3-O-HEC were easier to hydrate than the cellulose backbone. Furthermore the motion of water was more restricted (slower) in 2,3-O-HPC than in 2,3-O-HEC. For both polysaccharides the hydration could be explained by a two-step process: in step one increased ordering of the immobile regions occurs after which the entire polymer is hydrated in step two.
authors.affiliation: Department of Food Science, University of Copenhagen, Rolighedsvej 30, DK-1958 Frederiksberg C, Denmark.
authors.forename: Flemming H
authors.initials: FH
authors.lastname: Larsen
authors.affiliation: Thüringisches Institut für Textil- und Kunststoff-Forschung e. V., Eingetragener Verein, Breitscheidstraße 97, 07407 Rudolstadt, Germany; Institute of Organic Chemistry and Macromolecular Chemistry, Center of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Schöbitz
authors.affiliation: Thüringisches Institut für Textil- und Kunststoff-Forschung e. V., Eingetragener Verein, Breitscheidstraße 97, 07407 Rudolstadt, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Schaller
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D017666:Deuterium Oxide / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods
chemical_list: D002482:Cellulose; C002283:hydroxyethylcellulose; C008079:hydroxypropylcellulose; D017666:Deuterium Oxide