The fluidity and thixotropy of montmorillonite suspensions containing added hydrolyzed polyacrylamide show unusual thixotropic behavior in that they show in their natural state a neg. thixotropy (the fluidity of the suspensions increases with time). This neg. thixotropic behavior is time-dependent and exhibits clockwise hysteresis loops. The consistency of the suspension has a considerable influence on this unusual behavior and addns. of salts destroy the ability of the materials to build up a structure possessing a neg. thixotropic behavior.

Key words: POLYACRYLAMIDE, SUSPENSION, MONTMORILLONITE, THIXOTROPY