Effect of Amount of Ethyl Cellulose Microcapsules on the Corrosion Resistance of Polyurethane-based Self-healing Coating

In this study, Ethyl Cellulose (EC) microcapsules containing linseed oil have been prepared by emulsion-solvent evaporation method. The prepared microcapsules were then embedded in polyurethane (PU) paint to develop self-healing coatings and applied on steel substrate. In order to determine the effect of amount of EC microcapsules containing linseed oil on self-healing performance of the produced coating, PU-based coatings with various amount of prepared microcapsules were applied on plain carbon steel via spray method. The characterization of microcapsules core material was investigated by FT-IR spectroscopy and their shape and size were determined by Scanning Electron Microscope (SEM). The average diameter of microcapsules was obtained around 300 microns. The self-healing performance and corrosion resistance of the coatings were evaluated on samples with initial scratches on them, using Linear Polarization (LP) and Electrochemical Impedance Spectroscopy (EIS) tests. Results obtained revealed that, coatings containing microcapsules showed self-healing performance. Moreover, corrosion resistance of the self-healing coatings increased with increasing amount of EC microcapsules containing linseed oil and self-healing properties improved as well.