Synthesis and Characterization of Hydrophobically Associating Polyacrylamide Modified with Long Fatty Chain

ABSTRACT Hydrophobically associating polyacrylamide modified with long fatty chain P(AM-AA-ODAAMPS) was synthesized by free radical copolymerization with octadecyl acrylate (ODA), acrylamide (AM), 2-acrylamido-2-methyl propane sulfonic acid (AMPS), and acrylic acid (AA). The effect of influencing factors on the apparent viscosity of the copolymer solution in polymerization was discussed, and the optimum copolymerization condition was determined. Also, P(AM-AA-ODAAMPS) was characterized by infrared spectrum (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM). The diameter of the aggregation formed in the aqueous solutions of P(AM-AA-ODA-AMPS) with and without surfactant under the condition of reservoir temperature and salinity was measured by dynamic scattering. Rheometer was also employed to study the influence of surfactant on rheology of P(AM-AA-ODA-AMPS) solutions. The results showed that the optimum conditions were as follows: the mass fraction of ODA, AMPS, AA and KPS was respectively 0.6%, 20%, 10% and 0.3%. There were strong intermolecular hydrophobic association interactions in P(AM-AA-ODA-AMPS) aqueous solution. The diameter of the aggregation formed in P(AMAA-ODA-AMPS) solutions with and without surfactant is much smaller than the reservoir pore diameter and the influence of surfactant on rheology of P(AM-AA-ODA-AMPS) solutions is negligible. Therefore, P(AM-AA-ODA-AMPS) can be used in reservoirs with low permeability and high salinity as flooding agents with and without surfactant.