Stabilization of Polymer Nanocomposites in High-Temperature and High-Salinity Brines.

Stabilization of polymer nanocomposites in aqueous environment with high salinity has been a constant challenge for their applications. This work aimed to improve the stability of graphene oxide (GO) polyacrylamide nanocomposites at high-temperature and high-ionic-strength brines. GO was synthesized via a modified Hummers' method and the copolymer of acrylamide (COPAM) was obtained via free-radical polymerization. The covalent functionalization of COPAM with the partially reduced GO (rGO) was successfully achieved. 1,3-Propane sultone was used to further functionalize the obtained rGO-COPAM composites to accomplish the zwitterionic character on the rGO-COPAM surface to get a material with excellent temperature stability and dispersibility in the presence of high ionic strength brines. The synthesized materials were characterized by H NMR, gel permeation chromatography, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy analysis, and so forth. The thermal stability of the dispersion at 80 °C for 120 days was observed by visual inspection and spectroscopic analysis. The results showed that the zwitterionic polymer produced excellent brine stability with GO nanosheets and suggested promising applications of zwitterionic polyacrylamide-GO systems especially for enhanced oil recovery.