Hydration of biopolymers
| Autor: | I. C. Watt, R. L. D'Arcy |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of Polymer Science: Polymer Symposia. 55:155-166 |
| ISSN: | 1936-0959 0360-8905 |
| DOI: | 10.1002/polc.5070550117 |
| Popis: | Water-vapor sorption by a range of biopolymers is reviewed to demonstrate the general similarities in sorption characteristics. The interaction of water and the protein wool keratin is considered in more detail and further analyzed in terms of a three-component isotherm equation. Similar analyses have been applied to the water-vapor absorption isotherms of chemically modified wools and nylon 66. Changes in the secondary structure of wool affect the water content only at high humidities and have little effect below 80% R.H., where specific site absorption is the predominant mechanism. The analyses confirm that both the polar side chains and the peptide groups of the main polypetide chains provide specific sites for association of water molecules. Sorption hysteresis is shown to be dependent on the experimental procedure for determining “equilibrium” water content. By adopting an experimental technique which minimizes conformational changes during desorption of water from wool, sorption hysteresis is reduced and may be eliminated at low humidities. It is apparent that hysteresis water, when present, is not associated with specific sites but results from conformational changes in the substrate. |
| Databáze: | OpenAIRE |
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