title: Aqueous Modification of Nano- and Microfibrillar Cellulose with a Click Synthon.
abstract: The modification of cellulose as a renewable resource has received wide attention in research and industry. A major problem regarding chemical modification, including heating and drying, is related to hornification that causes pore-system collapse and results in decreased reactivity and changes in the 3D structure of the material. A mild and green approach for the modification of different never-dried and thus wet cellulose substrates (pulp, nanostructured celluloses, and viscose fibers) by an alkoxysilane-azide in water is presented. A kinetic study of the silanization reaction demonstrates that alkoxy-trans-silanization of the cellulose surface is accomplished in water as a suspension medium within a few hours at room temperature. The resulting, azido-equipped celluloses are widely applicable precursor materials for subsequent functionalization by so-called click chemistry, for example, with a fluorescent Rhodamine derivative as a representative reagent. Successful covalent bonding was shown by GPC and a model reaction. The 3D structure of the materials remained intact, as was inter alia visualized by optical and fluorescence microscopy.
authors.affiliation: University of Natural Resources and Life Sciences Vienna (BOKU), Department of Chemistry, Division of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria.
authors.forename: Hubert
authors.initials: H
authors.lastname: Hettegger
authors.affiliation: University of Natural Resources and Life Sciences Vienna (BOKU), Department of Chemistry, Division of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria.
authors.forename: Marco
authors.initials: M
authors.lastname: Beaumont
authors.affiliation: University of Natural Resources and Life Sciences Vienna (BOKU), Department of Chemistry, Division of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria.
authors.forename: Antje
authors.initials: A
authors.lastname: Potthast
authors.affiliation: University of Natural Resources and Life Sciences Vienna (BOKU), Department of Chemistry, Division of Chemistry of Renewable Resources, Konrad-Lorenz-Strasse 24, 3430, Tulln, Austria. thomas.rosenau@boku.ac.at.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rosenau
mesh_terms: D001386:Azides / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D057930:Click Chemistry; D061565:Cycloaddition Reaction; D007700:Kinetics; D008856:Microscopy, Fluorescence; D057139:Nanofibers / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D001386:Azides; D012821:Silanes; D014867:Water; D002482:Cellulose
keywords: cellulose; click reaction; fluorescence; green chemistry; siloxanes