Structure, surface tension, and rheological behaviors of hydrophobically associative polyacrylamides by self‐emulsified microemulsion polymerization

Abstract Hydrophobically associating copolymers using acrylamide (AM), acrylic acid (AA), and Styrene (St) as comonomers were successfully prepared by self‐emulsified microemulsion polymerization, in which low‐molecular‐weight AM/AA/St copolymers as surfactant and AM as cosurfactant. The structure and chemical composition of AM/AA/St copolymers were characterized by Fourier transform infrared, nuclear magnetic (NMR), and differential scanning calorimeter. The content of PSt in the copolymers is determined by 1 H nuclear magnetic resonance spectra, suggesting that the self‐made polymer surfactant can disperse uniformly the St monomers to improve the copolymerization efficiency. Furthermore, the polymerization mechanism of the self‐emulsified microemulsion method is explored preliminarily. During the synthesis of the copolymers, the purified copolymer solution is obtained in one step without using a small molecular emulsifier such as sodium dodecyl sulfate, in order to avoid the complicated post‐treatment process of the small molecular emulsifier. The copolymers revealed good hydrophobic association properties and low surface tension.