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Liquid ammonia treatment of (cationic) nanofibrillated cellulose/vermiculite composites

Authors

  • Thi Thu Thao Ho,

    Corresponding author
    1. Laboratory for Applied Wood Materials, Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Duebendorf, Switzerland
    • Swiss Federal Laboratories for Materials Science and Technology (EMPA), Applied Wood Materials, 8600 Duebendorf, Switzerland
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  • Tanja Zimmermann,

    1. Laboratory for Applied Wood Materials, Swiss Federal Laboratories for Materials Science and Technology (EMPA), 8600 Duebendorf, Switzerland
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  • Walter Remo Caseri,

    1. Department of Materials, Eidgenössische Technische Hochschule (ETH Zürich), 8093 Zürich, Switzerland
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  • Paul Smith

    1. Department of Materials, Eidgenössische Technische Hochschule (ETH Zürich), 8093 Zürich, Switzerland
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Abstract

Liquid ammonia was used to treat films of nanofibrillated cellulose (NFC), trimethylammonium-modified NFC (TMA-NFC), and their composites with vermiculite. Crystal structure, mechanical properties, water vapor permeation and water vapor adsorption of the resulting materials were investigated. Upon treatment, the crystal structure of (TMA-)NFC both in presence and absence of vermiculite changed from cellulose I to III. With the exception of TMA-NFC/vermiculite composites, pronounced effects on the addressed mechanical properties arose after exposure of the materials to ammonia. Furthermore, treatment of composite films with ammonia led to a distinct decrease in water vapor permeation. Remarkably, TMA-NFC/vermiculite composites films show the best water vapor barrier properties, highest tensile strength and highest elastic modulus after treatment with liquid ammonia. This is regarded to be at least partially a consequence of electrostatic attraction between the positively charged ammonium groups in TMA-NFC and the anionic silicate layers of vermiculite. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013

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