Synthesis and corrosion inhibition performance of a silane-modified ZnO/polymer nanocomposite on J55 carbon steel in CO₂-containing saline media

Objective To further extend the service life of J55 carbon steel in CO₂-saturated 3.5% NaCl solution, a novel polymer nanocomposite corrosion inhibitor (ZnO/PAVA) was designed and synthesized. Its corrosion-inhibition performance and mechanism were investigated through experimental and theoretical analyses. Methods Modified nano-zinc oxide was combined with 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid and vinyl acetate to synthesize the ZnO/PAVA polymer nanocomposite. The corrosion inhibition performance and mechanism of ZnO/PAVA in 3.5% NaCl solution saturated whit CO 2 were systematically analyzed using surface analysis, electrochemical weight loss tests, and theoretical simulation. Results ZnO/PAVA exhibited excellent corrosion inhibition performance. FTIR and XRD results confirmed its successful synthesis, while TEM images indicated that the modified nano-ZnO was uniformly dispersed in the polymer matrix with no obvious agglomeration. EIS and Tafel polarization curves yielded inhibition efficiencies of 89.56% and 91.96%, respectively, which were attributed to the formation of a protective film on the carbon steel surface. Further experiments using SEM-EDS and contact angle techniques confirmed its mechanism of action. Density functional theory (DFT) and molecular dynamics (MD) simulations also verified the microscopic mechanism. Conclusion ZnO/PAVA exhibits excellent corrosion inhibition performance for J55 carbon steel in 3.5% NaCl solution saturated with CO₂. Its outstanding corrosion inhibition effect is mainly attributed to the formation of a stable protective film on the J55 surface and a reduction in the charge transfer rate at the metal/medium interface. From a practical perspective, this study provides new ideas for the design and optimization of polymer nanocomposite anticorrosion agents.