New UV-Curable Anticorrosion Coatings from Vegetable Oils

Bio-based epoxy resins are attracting widespread interest in the field of polymer thermosets as environmentally friendly building block. In the present study, the feasibility of applying UV-curable epoxidized vegetable oils (EVOs) as anti-corrosion coating is investigated. Rheological characterization of EVOs is carried out, and their viscosity-shear relationship is evaluated. The cationic UV-curing of EVOs successfully gives rise to crosslinked materials with a wide range of thermo-mechanical properties, evaluated by differential scanning calorimetric analysis and dynamic thermal mechanical analysis. A high epoxy-group conversion, ranging from 93% to 99%, is always obtained. The thermal stability and surface properties of the bio-based coatings, such as, pencil hardness, adhesion, solvent resistance, and contact angle, are analyzed. Moreover, the corrosion protection effectiveness of the coatings is characterized by potentiodynamic polarization and electrochemical impedance spectroscopy measurements. In addition, field emission scanning electron microscopy is used to assess the samples morphology after corrosion tests.