Etude de la stabilité colloïdale du latex de caoutchouc naturel

Abstract : This work, in collaboration with Michelin for the fabrication of composite materials, deals with the colloidal stability of the latex of natural rubber (NR). The NR latex is a polydisperse colloidal dispersion of a bio-polymer in an aqueous serum. The particles are stabilized by a complex layer of phospholipids and proteins. This dispersion can be coagulated by a physical way (under shearing), or by a physical-chemicalway (addition of divalent cations or hydrophobic particles). In this thesis, we studied the coagulation of the NR latex by divalent cations with physical-chemical tools (stability diagrams with different cations, aggregation kinetic of particles, rheological measuremments). Then, the surface of NR particles has been characterized by electrophoresis, firstly in the presence surfactants and secondly depending on the particles size. From the results of the first part we suggest that the coagulation with divalent cations is due to a screening effect because of the increase of ionic strength and that divalent cations can bridge the particles together. This allows keeping them in contact. Adhesion between polymer chains near the surface ensures the irrversible cohesion. In a second time, we saw that the adsorption of surfactants changes the particles surface and the coagulation of NR latex with cations. A small difference of surface charge is observed between the biggest and the smallest NR particles. Finally, a similar behavior has been obtained with a synthetic latex in presence of divalent cations. Our results could be used to develop an industrial process based on this coagulation phenomenon.
Complete list of metadatas

https://pastel.archives-ouvertes.fr/tel-01178787
Contributor : Fanny Alousque <>
Submitted on : Monday, July 20, 2015 - 8:26:16 PM
Last modification on : Thursday, July 4, 2019 - 11:00:07 AM
Long-term archiving on : Friday, May 5, 2017 - 11:43:00 AM

Licence


Distributed under a Creative Commons Attribution - NonCommercial - NoDerivatives 4.0 International License

Identifiers

  • HAL Id : tel-01178787, version 1

Collections

Citation

Fanny Alousque. Etude de la stabilité colloïdale du latex de caoutchouc naturel. Chimie-Physique [physics.chem-ph]. Université Pierre et Marie Curie, 2014. Français. ⟨tel-01178787⟩

Share

Metrics

Record views

535

Files downloads

1740