Abstract
To study the time-dependent properties of clay gels in the structural rejuvenation mode, a combination of the stepdown shear rate method and an ageing test is advocated. In this mode, the structural development process at two different initial equilibrium states during the low stepdown shear rate and the rest period of the ageing test were followed. The roles played by the electric double layer (EDL) repulsive force in this structural development process with and without shear, for platelet sodium montmorillonite or NaMnt, hectorite and Laponite gels, and fibrous sepiolite gels were assessed. The response of the stepdown shear stress and ageing yield stress reflects the action of these forces on the structural rejuvenation kinetics and the type of structure formed. The platelet clay gels with their strong EDL repulsive particle interaction commenced the structural development process immediately and formed an open network structure. This process is short in shear and takes years when without. The fibrous sepiolite gel with its weak EDL repulsive interaction did not display structural rejuvenation in shear and only showed a significant yield stress increase after the first few hours of ageing. An additional issue concerning the stability of the isotropic liquid (IL) phase state of dilute Laponite dispersions was addressed. These dispersions aged for >9 years, displaying that yield stress and network structure confirmed that the IL phase is unstable. A low energy path available for Laponite particles to aggregate was discussed. A new method for determining the flocculate phase state was also presented.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
