A characterization of tung oil-filled Urea-Formaldehyde microcapsules and their effect on mechanical properties of an epoxy-based coating

Abstract

The development of smart coatings with possible for active anticorrosion and self-healing protection of metals is essential for long-term performance of metallic structures in marine environments. In this study, tung oil-filled Poly-Urea-Formaldehyde (PUF) capsules were created utilising in-situ polymerization, and 7.5 wt.% of synthesized microcapsules were combined with commercial epoxy paint. The poly-urea-formaldehyde (PUF) microcapsules with linseed oil encapsulation had a core content of about 80 % and a diameter of 180 µm. Self-healing coatings were realized by the releasing of tung oil from microcapsules under the scarp area. Tung oil has excellent film-forming property when they contact with oxygen, self-healing anti-corrosion properties. The performance of the self-healing coating was examined through immersion testing in 3.5 wt% medium for 7, 14, 21, 28 and 35 days. The microcapsule, self-healing capability, and surface morphology of the substrate following the corrosion test were all characterised using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), weight loss, and corrosion rate methods. The experimental result indicate that the scratched of self-healing coating samples were able to resist corrosion behavior in salt solution thus, the microcapsules can be used to significantly extend the service life of the coatings. Compared to uncoated and epoxy coating, the self-healing coating exhibits superior anticorrosive capabilities after immersion testing. A more profound knowledge of the self-healing process to extend life could result from this research.