Structure, rheology and stability of concentrated disperse systems under dynamic conditions

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 1994-07, Vol.87 (1), p.1-14
• Main Author: Uriev, N.B.
• Format: Article
• Language: English
• Subjects: Concentrated disperse systems; Dynamic conditions; Rheological properties; Stability; Structural properties
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/0927-7757(93)02611-H

This paper presents the results of an investigation of the structural and rheological properties, and the aggregation and sedimentation stabilities of structured concentrated disperse systems under dynamic conditions (shear and vibration). The full rheological flow curve is described on the basis of the mechanism of aggregative disintegration of the structure in flow. Using a new method for the visualization of the process of flow of structured disperse systems, the laminar character of the flow has been detected as a consequence of disruptions of continuity in structure and the formation of structural layers from aggregates in the shear flow. A computer simulation substantiates the flow mechanism described. It has been shown that disruptions of continuity and the laminar structure are eliminated under the effect of vibrations orthogonal to the direction of the continuous shear deformation. The phenomenon of the synergistic effect of mechanical vibration and additions of surfactants on the structure failure processes has been detected and is described. The latter is essential for attaining the maximum flowability of concentrated disperse systems in various heterogeneous chemical processes.