Copolymer nanocomposites with strong adsorption of exfoliated silicate nanosheets and high-temperature stability

Abstract

Exfoliated layers of two-dimensional materials with high surface activity can adsorb polymer chains to induce nucleation effects and enhance the high-temperature resistance of polymer nanocomposites. Herein, a novel polymer nanocomposite (AAS/I-Mt), comprising acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), sodium p-styrenesulfonate (SSS), and sodium 1-dodecanesulfonate-intercalated montmorillonite (I-Mt), was prepared via in situ polymerization. The composition, structure, and morphology of AAS/I-Mt were confirmed using various characterization methods. Thermogravimetric analysis and high-temperature apparent viscosity measurements demonstrated the excellent thermal stability of AAS/1.0 wt% I-Mt. After aging at 200 °C for 16 h, the apparent viscosity of a 10 g L⁻¹ AAS/1.0 wt% I-Mt aqueous solution was 251.7 mPa s. Moreover, after aging at 180 °C for 16 h, the fluid loss under the American Petroleum Institute standard conditions (FL_API) was 8.0 mL in a fresh-water-based drilling fluid system with 1.0 wt% AAS/1.0 wt% I-Mt, compared to 39.1 mL in the similar system without AAS/1.0 wt% I-Mt. Furthermore, the FL_API of a saturated brine-based drilling fluid system with 1.0 wt% AAS/1.0 wt% I-Mt was 8.6 mL. Additionally, scanning electron microscopy, transmission electron microscopy, and zeta potential analyses suggested the strong adsorption between the exfoliated I-Mt nanosheets and polymer chains. The uniformly dispersed nanosheets in AAS/I-Mt thickened and toughened the polymer chains and decreased the porosity of the nanocomposite, reducing the fluid loss in water-based drilling fluids at high temperatures. The multifunctional AAS/I-Mt polymer nanocomposite shows potential as an effective additive in high-temperature oil and gas water-based drilling fluids.