Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8333389 | International Journal of Biological Macromolecules | 2013 | 6 Pages |
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.
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Authors
Michiko Shimizu, Hayaka Fukuzumi, Tsuguyuki Saito, Akira Isogai,