preparation of composite hydrogel based on polyacrylamide and the effect of kaolinite on its properties in the reservoir conditions

a gel composite (based on polyacrylamide and crosslinker cr(iii) acetate) was prepared by solvent method (distillate and water formation) and nanoclay particle (kaolinite). using xrd tests, d001 was evaluated for kaolinite nanoparticles in gel composite. kaolinite modification using dimethyl-sulfoxide led to increase interlamellar spacing from 7.21 to 10.82 o a. based on the results obtained for samples prepared from unmodified clay besides the pure clay, there is a wide peak at 2θ = 8o; which is a representative of polymer diffusion between the clay layers. for the sample prepared from modified clay, no increase in interlamellar space was observed. addition of 15% clay (modified and unmodified) caused the syneresis to reduce by 20%. the gelation time for composites prepared from both types of clays increased due to increases in clay concentration, which this increase for the sample prepared from unmodified clay was greater. the viscosity of gel for samples prepared from modified clay increased due to increased clay concentration, which reached its maximum for 15% clay concentration. however for unmodified clay the maximum value of viscosity was observed for 30% clay concentration.