Modified acrylamide copolymers based on β-cyclodextrin and twin-tail structures for enhanced oil recovery through host–guest interactions

Abstract

β-Cyclodextrin has attracted considerable attention due to its unique structure with a hydrophobic cavity and a hydrophilic rim, allowing hydrophobic guest molecules to enter the hydrophobic cavity from aqueous solution to form stable host–guest inclusions. Based on this, two kinds of copolymers with host–guest interaction based on modified β-cyclodextrin and hydrophobic twin-tail structures, which are expected to be alternatives to currently used copolymers in the oil field, were successfully synthesized via free-radical copolymerization in this study. Subsequently, the copolymers were characterized by FT-IR, ¹H NMR, SEM and TG-DTG to confirm that they were prepared successfully and exhibited favorable thermal stability. Furthermore, the copolymers could enormously increase the viscosity of the aqueous solution compared with partially hydrolyzed polyacrylamide. And static experiments have convincingly proved that the β-cyclodextrin and twin-tail structure endowed the copolymers with excellent shear resistance, temperature resistance, salt tolerance, and viscoelasticity. Core flooding experiments further indicated that this unique type of host–guest interaction can make the copolymers have great potential for enhanced oil recovery.