Specific Interactions in Modified Chitosan Systems

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• 作者：M. Rinaudo ; R. Auzely ; C. Vallin ; and I. Mullagaliev
• 刊名：Biomacromolecules
• 出版年：2005
• 出版时间：September 2005
• 年：2005
• 卷：6
• 期：5
• 页码：2396 - 2407
• 全文大小：220K
• 年卷期：v.6,no.5(September 2005)
• ISSN：1526-4602

文摘

This paper concerns the bulk and interfacial properties of a series of alkylated chitosans having differentalkyl chain lengths grafted randomly along the main chitosan chain. Chitosan has a low degree of acetylation(5%); on chitosan derivatives, the role of the degree of grafting and of length of the alkyl chains are examined.The optimum alkyl chain length is C12 and the degree of grafting 5% to get physical gelation based on theformation of hydrophobic domains. The cross-linking is essentially controlled by the salt concentration: itis shown that 0.025 M AcONa is needed to screen electrostatic interchain repulsions. Hydrophobic interactionsproduce highly non-Newtonian behavior with large thinning behavior; this behavior is suppressed in thepresence of cyclodextrins able to cap the hydrophobic alkyl chains.The interfacial properties of the chitosanderivatives were tested for the air/aqueous solution interfaces. Specifically, the role of their structure on thekinetic of film formation was examined showing that excess of external salt favors the stabilization of theinterfacial film. The derivatives with a higher degree of substitution and longer alkyl chains are more efficientand give a higher elastic modulus compared to the model surfactant as a result of the chain properties.