Encapsulation of tung oil for self-healing coatings in corrosion applications

Abstract

Encapsulation of tung oil for use in self-healing applications using urea-formaldehyde as the shell was performed via in-situ polymerization. Microcapsules ranging from 100 to 250 μm with a shell wall thickness of 1.7–2.6 μm were obtained. Infrared spectroscopy and scanning electron microscopy were used to characterize the microcapsules. The self-healing performance of steel substrates coated with tung oil microcapsules in epoxy was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The surface roughness of the coated specimens was evaluated by atomic force microscopy and contact angle measurements. Coatings that contained smaller microcapsules were found to exhobit a higher corrosion resistance and lower roughness than coatings containing larger microcapsules.