Controlling Suspension Rheology with Novel Oligomeric Dispersants

摘要

Suspensions of cationic boehmite (Catapal 200) exhibit “challenging” rheological properties—irreversible shear thickening to viscoelastic or jammed states, dependent on the shear history. A range of commercially available dispersants—either small molecules or polymers—were able to reduce viscosity but not able to eliminate shear-induced jamming. We designed and synthesized oligomeric functional anchor-buoy dispersants, with a small, strongly adsorbing carboxylic acid based anchor and a simple, inexpensive water-soluble oligomeric buoy (typically 25–30 acrylamide units). In the presence of the dispersant, the viscosity was reduced and irreversible shear thickening eliminated.