Synthesis of Hydrophobic Associating Polymers and Investigation of Their Adsorption Behavior on Carbonate Rock Matrix

Abstract Herein, using acrylamide (AM), methyl acryloyloxyethyl trimethyl ammonium chloride (DMC), and octadecyl polyoxyethylene ether methacrylate (OEMA) as raw materials, a ternary copolymer (PADO) with hydrophobic association between molecules is synthesized. The structure of this copolymer is characterized via Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Its average acid–rock reaction rate at 90 °C is 3.43 × 10 −6 g/(cm 2 ·s), indicating good retardation performance, respectively. Adsorption isotherm and critical association concentration (CAC) measurements reveal that when PADO reaches CAC, it adsorbs on carbonate rock via multilayer adsorption. The Zeta potential reverses after PADO adsorption, and the polarity of PADO is larger than that of PAD. X‐ray photoelectron spectroscopy shows that the lone pair of electrons on the oxygen atom in the hydrophobic segments of PADO forms new coordination chemical bonds with calcium ions in carbonate rock. Upon introducing the hydrophobic monomer OEMA, PADO adsorbs on the carbonate rock surface via chemical adsorption. This hinders hydrogen ion transfer in the PADO network, and the adsorption film prevents the direct contact of hydrogen ions with the carbonate rock surface. These findings provide an effective theoretical basis for analyzing the adsorption mechanism of hydrophobic associative polymers.