Preparation and characterization of microcapsules based self-healing coatings containing epoxy ester as healing agent

Cracks caused by chemicals or mechanical forces would damage the performance of coatings leading to the coating failure. Microcapsules based self-healing smart coatings can provide automatic recovery and extend the durability of coatings. In this study, poly urea-formaldehyde microcapsules contained tall oil fatty acid basede-poxy ester as core materials were synthesized through in situ polymerization. The synthesized microcapsules were characterized by scanning electron microscope (SEM), optical microscope, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The core content of microcapsules was 67 wt. %; the average diameter of microcapsules was 101 +/- 48 mu m. The self-healing coatings were prepared by embedding the poly (urea-formaldehyde)-epoxy ester (PUF-epoxy ester) microcapsules into epoxy coatings. Salt spray, SEM, and electrochemical impedance spectroscopy were examined, and the self-healing coatings exhibited satisfactory self-healing property and sufficient corrosion resistance recovery.