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Swelling and Dissolution of Cellulose Part II: Free Floating Cotton and Wood Fibres in NaOH–Water–Additives Systems
Author(s) -
Cuissinat Celine,
Navard Patrick
Publication year - 2006
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200651202
Subject(s) - swelling , dissolution , cellulose , chemical engineering , urea , materials science , solvent , polymer chemistry , chemistry , nuclear chemistry , composite material , organic chemistry , engineering
Summary: The swelling and dissolution mechanisms of native cotton and wood cellulose fibres in NaOH–water are studied. The cellulose fibres exhibit a heterogeneous swelling by ballooning in the best dissolving conditions (−5 °C, 7.6% of NaOH). This corresponds to the mode 3 of the swelling‐dissolution (see companion paper). In this region of the mixture phase diagram, cellulose is only dissolved inside the balloons. A lot of insoluble parts are present. Increasing the temperature and/or the content of NaOH decreases the quality of the solvent. In this case, the cellulose fibres do not show ballooning, but only a homogeneous swelling (mode 4). Three components are tested as additives: urea, zinc oxide and N ‐methylmorpholine– N –oxide (NMMO). The swelling and dissolution mechanisms in NaOH‐water and NaOH–water–additives stay the same. Adding urea to NaOH‐water (−5 °C, 7.6% of NaOH) gives the same ballooning mechanisms, but with a larger expansion of the balloons, indicating that the solvent is better. Zinc oxide does not increase the expansion of the balloons, but the kinetics of swelling is faster. NMMO acts as a dissolution inhibitor.