Preparation and rheological properties of associative salt tolerant polymer by inverse-phase emulsion polymerization

Abstract An associative and salt tolerant p(AM/AMC12S/GTE-10) polymer was synthesized through reverse-phase emulsion polymerization of acrylamide (AM), 2-acrylamide-sodium dodecyl sulfonate (AMC12S), and the hydrophobic monomer 29-(4-octylphenoxy)-3,6,9,12,15,18,21,24,27-nonaoxanonacosyl methacrylate (GTE-10). The structure and morphology of the polymer obtained were then characterized by FTIR, 1H-NMR, SEM, TEM, and a laser particle size distribution analyzer. This was followed by an evaluation of its rheological properties, thixotropic properties, and viscoelasticity. The results showed that the hydrophobic monomer GTE-10 was successfully incorporated into the polymer, resulting in a narrow and uniform particle size distribution of the emulsion after polymerization. The addition of salt made the aggregation of p(AM/AMC12S/GTE-10) molecules more compact, resulting in a more stable spatial network structure. The p(AM/AMC12S/GTE-10) polymer aqueous solution with a mass fraction of 0.7% exhibited excellent temperature resistance at 140 ℃. After being sheared at 120 ℃ and 170 s–1 for 1 h, the polymer solutions with a mass fraction of 0.7%, prepared at a mass concentration of 20000 mg/L NaCl and CaCl2 aqueous solutions exhibited viscosities of 64.7 and 54.2 mPa·s, respectively, with good shear recovery performance. The energy storage modulus was higher than the loss modulus, and the complex interaction between the metal ion and phenoxyethylene group enhanced the intermolecular forces, resulting in a more stable spatial structure and increased viscoelasticity.