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Coagulation rate studies of spinnable chitosan solutions

✍ Scribed by Jonathan Z. Knaul; Katherine A. M. Creber


Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
307 KB
Volume
66
Category
Article
ISSN
0021-8995

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✦ Synopsis


The coagulation properties of some mixtures of 5% chitosan in 2% aqueous acetic acid were investigated with the goal of determining the optimal coagulation conditions for the spinning of chitosan fibers. The chitosan was characterized and found to possess a deacetylation value of 84.9 { 0.2%. Molecular weight of the chitosan was also measured; based on intrinsic viscosity, the M V value was 7.73 1 10 5 g mol 01 , and based on high-pressure liquid chromatography, the M w value was 1.14 1 10 5 g mol 01 . Solutions of 5% chitosan/2% acetic acid were prepared, filtered, and extruded through a large-diameter hole syringe into coagulation baths of varying composition that were all strongly basic in nature, at least a pH of 12 or greater. For each coagulant, time was varied from between 22 s and 2 minutes at room temperature. A second set of experiments was conducted where the temperature was varied from 20ЊC to 70ЊC at a constant time of 45 s. In a third set of experiments, using a 1 M NaOH coagulant, different chitosans were also analyzed. Throughout all of the experiments, a distinct moving boundary between coagulated and uncoagulated polymer was observed within the cylindrical-shaped polymer fibers. Using a series of equations based on Fick's 2nd Law, a straight line relationship has been demonstrated between boundary motion and time and between boundary motion and temperature for each coagulant tested. The activation energy for each coagulant was also determined.


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