title: Preparation and characterization of TEMPO-oxidized cellulose nanofibrils with ammonium carboxylate groups.
abstract: Fibrous TEMPO-oxidized celluloses with 100% ammonium carboxylate groups (TOC-COONH4) were prepared by adding aqueous ammonia to fibrous TOC-COOH/water slurries. Using a gentle mechanical disintegration treatment in water, the obtained never-dried TOC-COONH4/water slurries could be converted to highly viscous and transparent gels consisting of mostly individualized TEMPO-oxidized cellulose nanofibrils. The self-standing TOCN-COONH4 film prepared from the aqueous TOCN-COONH4 dispersion via casting and drying had high optical transparency. When the self-standing TOCN-COONH4 film was heated at 105°C for 1 day, clear yellowing was observed on the film. FT-IR analysis of the heated TOCN-COONH4 films indicated the partial formation of TOCN-COOH type structures from the TOCN-COONH4 due to evaporation of NH3 gas from the films during heating. The heated TOCN-COONH4 films had lower moisture contents, higher film densities, and higher Young's moduli than the unheated TOCN-COONH4 films.
authors.affiliation: Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Shimizu
authors.forename: Hayaka
authors.initials: H
authors.lastname: Fukuzumi
authors.forename: Tsuguyuki
authors.initials: T
authors.lastname: Saito
authors.forename: Akira
authors.initials: A
authors.lastname: Isogai
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D002483:Cellulose, Oxidized / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D055119:Elastic Modulus; D057139:Nanofibers / Q000737:chemistry*; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water
chemical_list: D064751:Ammonium Compounds; D002483:Cellulose, Oxidized; D003497:Cyclic N-Oxides; D014867:Water; C003959:TEMPO