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Synthesis of new high molecular weight phosphorylated chitosans for improving corrosion protection

Coquery, Clément and Negrell, Claire and Caussé, Nicolas and Pébère, Nadine and David, Ghislain Synthesis of new high molecular weight phosphorylated chitosans for improving corrosion protection. (2019) In: 17th Polymers and Organic Chemistry (POC-2018), 4 June 2018 - 7 June 2018 (Palavas les Flots,, France).

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Official URL: https://doi.org/10.1515/pac-2018-0509

Abstract

Two grades of chitosan [chitosan 30000 g mol−1 (N-chitosan 30) and 250000 g mol−1 (N-chitosan 250)] were functionalized by the Kabachnik–Fields reaction. To obtain the highest phosphonic ester grafting rate (55% and 40% for the N-chitosan 30 and N-chitosan 250, respectively), the pH must be kept constant during the reaction (pH=5). Then, a partial hydrolysis of the ester functions was carried out in HCl medium to generate phosphonic acid functions up to 25% and 20% for the N-chitosan 30 and N-chitosan 250, respectively. It was shown that the grafting of phosphonic acids on chitosan significantly reduced the dynamic viscosity. Afterwards, electrochemical impedance measurements were performed in an aqueous solution (pH=5) in the presence of either N-chitosans or P-chitosans (3 wt.%). The two native N-chitosans were little adsorbed onto the carbon steel surface and the corrosion protection was low. In contrast, the impedance results in the presence of the 30000 g mol−1 phosphorylated chitosan (P-chitosan 30) evidenced the beneficial effect of grafted phosphonic acid on its adsorption on the steel surface. The lower efficiency of the 250000 g mol−1 (P-chitosan 250) was attributed to its high molecular weight which made difficult the interactions between the phosphonic groups and the metallic surface.

Item Type:Conference or Workshop Item (Paper)
Additional Information:IUPAC & De Gruyter. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives
HAL Id:hal-02067816
Audience (journal):International peer-reviewed journal
Audience (conference):International conference proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Ecole Nationale Supérieure de Chimie de Montpellier - ENSCM (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
Other partners > Université de Montpellier (FRANCE)
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Deposited By: Yves MOMBOISSE
Deposited On:06 Nov 2019 15:25

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