Effect of Silane-Functionalized RuO2 Nanoparticles on the Anticorrosive and Mechanical Properties of Poly (Methyl Methacrylate) Coatings

Abstract

Newly synthesized poly (methyl methacrylate) (PMMA), silane, and nano ruthenium oxide (PMMA/silane/RuO2) nanocomposite coatings on Al alloy (AA7475) in chloride media were evaluated for their anticorrosion and mechanical properties. Three different silanes, trimethoxyphenylsilane (TPS), trimethoxy(3-glycidyloxypropyl)silane (TGS), and trimethoxy(3-mercapto propyl) silane (TMS), were used to functionalize the RuO2 nanoparticles that were incorporated into PMMA to produce PMMA-TPS/RuO2, PMMA-TGS/RuO2, and PMMA-TMS/RuO2 nanocomposite coatings. Electrochemical impedance spectroscopy (EIS) showed a profound coating (Rc) and charge transfer (Rct) resistance and polarization studies demonstrated a noticeable reduction in the corrosion current density (icorr) using PMMA-TPS/RuO2, PMMA-TGS/RuO2, and PMMA-TMS/RuO2 nanocomposites. The resulting nanocomposite coatings behaved as the best protective passive layer, which prevented the diffusion of the electrolyte and, thus, increased the life span of the coating. Embedding the silane-functionalized RuO2 into PMMA coating provided improved protective properties. Scanning electrochemical microscopy (SECM) detected the least current over the defects of the coated surface, confirming the barrier properties of the investigated nanocomposite coatings. Field emission-scanning electron microscopy (FE-SEM)/energy dispersive X-ray (EDX) spectroscopy confirmed the presence of passive films, which protected the dissolution aluminum alloy. The investigated coated materials were examined by mechanical testing, which complimented the electrochemical results. The improvement of the protective and mechanical properties of the nanocomposites consisting of PMMA/silane/RuO2 made these potential coating materials for use in the aerospace industry. The superior anticorrosive property of the proposed coatings provides a new horizon in industrial anticorrosive coatings.