Effect of Cr(III) Acetate Concentration on the1H NMR Behavior of HPAm/Cr(III) Acetate Gels

Partly hydrolyzed polyacrylamide-Cr(III) acetate (HPAm/Cr(III) acetate) aqueous gel systems formulated with HPAm to Cr(III) acetate weight ratios ranging from 5/1 to 60/1 and 5000 mg/L of HPAm were monitored using 1H nuclear magnetic resonance (1H NMR), bottle testing, and oscillatory rheology. The chemistry of the Cr(III) acetate complex dominated the 1H NMR response of the formulations that did not form a continuous network structure. 1H NMR detected gelation time and syneresis evolution in the formulations that rendered a continuous gel network structure.