Paper Number
GG38
Session
Rheology of Gels, Glasses and Jammed Systems
Title
Phase diagram and rheology of polymer-carbon black aqueous suspensions
Presentation Date and Time
October 12, 2022 (Wednesday) 10:50
Track / Room
Track 3 / Sheraton 5
Authors
- Legrand, Gauthier (ENSL, CNRS, Laboratoire de physique)
- Manneville, Sébastien (ENSL, CNRS, Laboratoire de physique)
- Divoux, Thibaut (ENSL, CNRS, Laboratoire de physique)
Author and Affiliation Lines
Gauthier Legrand, Sébastien Manneville and Thibaut Divoux
ENSL, CNRS, Laboratoire de physique, Lyon, France
Speaker / Presenter
Legrand, Gauthier
Keywords
experimental methods; colloids; gels; glasses; polymer solutions
Text of Abstract
Carbon Black (CB) colloidal particles are combustion residues commonly used in industry for their mechanical and electrical properties in a wide range of applications such as inks, tire strengthening, and flow batteries. When dispersed in mineral oil, these particles aggregate under the effect of Van der Waals interactions and form a gel, i.e., a percolated network even at very low mass fractions, of the order of 0.1%. These gels behave as viscoelastic solids at rest and flow like viscous liquids beyond a critical stress, or under the effect of large deformations.
Here we report on the rheological properties of aqueous suspensions of carbon black. The dispersion in water of these hydrophobic particles is made possible by adding a cellulose ether, namely carboxymethylcellulose (CMC). First, we will discuss the behavior of these CB–CMC aqueous suspensions through a phase diagram in the (%wt. CB, %wt. CMC) plane, which exhibits four prominent behaviors: phase demixion, viscoelastic liquid, viscoelastic solid and brittle paste. In this study we mainly focus on the viscoelastic solid properties. Unlike dispersions of CB in oil, a critical mass fraction of CB, of the order of 5 to 10%, is necessary to obtain a viscoelastic solid. Moreover, two asymptotic behaviors are observed above this critical mass fraction of CB depending on whether the amount of CMC in solution is larger than the overlap concentration of the polymer solution C*. Comparing suspensions at 8%wt. CB, we observe that for C > C*, the behavior of the mixture is dominated by the polymers, whereas for C < C*, the behavior of the mixture is dominated by the colloids.