In situ monitoring the sol-gel transition for polyacrylamide gel

The effects of heating rate and shear stress on the sol-gel transition for a polyacrylamide gel during in situ preparation were investigated by dynamic rheology. The gelation evolution was also studied through monitoring of the static gelation process by means of temperature, pH, and conductivity variation. The gels were prepared by polymerization of acrylamide crosslinked with N, N'-methylenebisacrylamide using a redox initiation based on potassium persulfate/ascorbic acid. In situ gelation process was studied using oscillatory deformation tests at constant frequency of 0.1 Hz for different heating rate ( from 0.5 to 5 degrees C/min) and shear stress (in the range of 0.1 to 10 Pa).