Kinetics of chitosan coagulation from aqueous solutions |
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| Authors: | Alin Alexandru Enache Laurent David Jean‐Pierre Puaux Ionut Banu Grigore Bozga |
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| Affiliation: | 1. Laboratoire Ingénierie des Matériaux Polymères, Université Lyon 1, Centre National de la Recherche Scientifique Unité Mixte de Recherche (France) 5223, 15 Boulevard André Latarjet, Polytech Lyon, Villeurbanne Cedex, France;2. Department of Chemical and Biochemical Engineering, Politehnica University of Bucharest, 1 Polizu Street Bucharest, Romania |
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| Abstract: | In this study, we investigated the kinetics of chitosan hydrogel formation from aqueous chitosan solutions with sodium hydroxide (NaOH) as the coagulant. Two sets of experiments were performed, one in a parallelepiped cell and the other with cylindrical chitosan solution extrudates. The coagulation occurred by the neutralization of the protonated amino groups (?  ) present in the chitosan chains, with the kinetics being controlled by NaOH transport toward the gelification zone. In this study, we confirmed the appropriateness of Fick's second law to describe NaOH transport, considering the instantaneous reaction between the NaOH and ?  groups. The experimental data were used to determine the NaOH diffusion coefficient in gels having different chitosan concentrations. The diffusion coefficient values obtained from the cylindrical coagulation data were lower than those determined for linear coagulation because of the influences of transport geometry and gel structure, respectively. Accordingly, in fiber coagulation calculations, it is recommended to use diffusion coefficient values determined from cylindrical coagulation studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46062. |
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| Keywords: | biopolymers and renewable polymers gels theory and modeling |
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