Influence de cations métalliques sur les propriétés physico-chimiques de carboxyméthyl-dextrane fonctionnalisé

Abstract : The present work focused on the acquisition of experimental and quantitative data on the physico-chemical properties of a linear, flexible and chemically functionalized polysaccharide by carboxymethyl grafting, yielding carboxymethyldextran macromolecules (CMD) and an aqueous electrolyte containing various ions Na+, Ca2+ et Cd2+ with different chemical affinity for these chemical functions. Charge density and complexation dissociation constants have been evaluated using specific electrodes-based potentiometric titration. The electro-hydrodynamic properties and the conformational transitions were examined through electrical conductivity increment measurements, electrophoresis, dynamic light scattering and viscosimetry. Also, colloidal stability has been investigated by means of turbidimetry and dynamic light scattering. In the presence of monovalent ions, the behaviour of CMD, typically that of a soft microgel particle, is strongly depending on ionic strength and polysaccharide content. For low ionic strengths and in dilute regime, CMD is in situation of good solvent while in concentrated regime, overlapping double layers that develop around macromolecules governs the electro-hydrodynamic features of CMD. For sufficiently high ionic strengths, intermolecular and intramolecular electrostatic interactions are nearly suppressed, and CMD behaves as a polymer in bad solvent upon increase of its concentration in the medium. In the presence of divalent ions, calcium ions and cadmium ions are in competition with hydronium ions to occupy the carboxylic sites, and this situation is concomitantly accompanied by local reorganization of polymer chains. The large size of formed clusters, the high initial aggregation rate and the increased turbidity all suggest that aggregates are generated according to a diffusion limited aggregation (DLA) type of mechanism
Complete list of metadatas

Cited literature [241 references]  Display  Hide  Download

https://hal.univ-lorraine.fr/tel-01753036
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 2:05:13 PM
Last modification on : Monday, April 16, 2018 - 10:42:47 AM

File

2008_SAGOU_S_J_P.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01753036, version 1

Collections

Citation

Sagou Jean-Pierre Sagou. Influence de cations métalliques sur les propriétés physico-chimiques de carboxyméthyl-dextrane fonctionnalisé. Sciences de la Terre. Institut National Polytechnique de Lorraine, 2008. Français. ⟨NNT : 2008INPL072N⟩. ⟨tel-01753036⟩

Share

Metrics

Record views

93

Files downloads

73