Hypothesis: Metal corrosion, an inevitable and detrimental phenomenon poses significant economic, environmental, and engineering challenges across various industries. Polyurethane coatings, renowned for their excellent adhesion to metal surfaces, mechanical strength, and chemical resistance, have emerged as a cost-effective and efficient solution to mitigate corrosion. Recent research has focused on advancing these coatings to eliminate volatile organic compounds (VOCs), incorporate natural materials, and enhance their corrosion resistance through the integration of nanoparticles.
Methods: In this study, waterborne polyurethanes (WPUs) were initially synthesized using renewable and biocompatible castor oil as a polyol. To enhance the corrosion resistance of the prepared coatings, two waterborne samples containing pristine graphene oxide (GO) nanoparticles and graphene oxide (GO) nanoparticles modified with p-tert-utylcalix[4]arene (BC4A) were prepared via in-situ polymerization. The structural properties of the nanocomposites were characterized using ATR-FTIR XRD, contact angle measurements, SEM and TGA. Subsequently, the corrosion resistance of these coatings was investigated using EIS and PDS techniques
Findings: DLS analysis confirmed the stability of the dispersions. SEM images revealed that C4A-GO nanosheets exhibited superior dispersion within the polymer matrix compared to unmodified GO nanosheets. To assess the corrosion resistance of the coatings, EIS and PDS tests were conducted. The corrosion current density (I_corr) and charge transfer resistance (R_ct) values for the WPU/C4A-GO sample were 8 × 10^-9 A/cm² and 629610 Ω.cm², respectively, indicating its potential as a corrosioninhibiting filler. Overall, the in-situ synthesis of polyurethane with nanoparticles significantly enhanced the corrosion resistance of the coatings. This improvement is attributed to the incorporation of nanoparticles into the polymer matrix, the formation of cross-links within the polyurethane structure, and increased surface hydrophobicity.