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In a previous study, self-healing polyurethane coatings with microcapsules containing healing agents were developed to protect of metal against corrosion. At the initial stage in developing these coatings, we synthesized microcapsules containing healing agents by adding organic solvents to inhibit solidification of the entire capsule. In this study, we examined the structure of the capsules formed with different solvents, such as chlorobenzene, toluene, and xylene. We also evaluated the self-healing ability of coatings with these capsules after damaging the coating by scratching. The amount of healing agents contained in capsules depends on the kind and amount of solvents added. In a capsule formed with 20 or 50 wt % chlorobenzene, there is almost no liquid-phase healing agent, while the capsule formed with 70 wt % chlorobenzene contains healing agents. Toluene and xylene are more effective inhibitors than chlorobenzene. The capsule formed with 70 wt % toluene or xylene contains much greater amounts of liquid-phase healing agent than that formed with 70% chlorobenzene, and the coatings with the former have an appreciable self-healing ability. [ABSTRACT FROM AUTHOR]

In a previous study, self-healing polyurethane coatings with microcapsules containing the high reactive liquid phase were developed to protect metal from corrosion for long periods. In this study, we examine the effect of the amount of glycerol added in the microcapsule formation process on the shape of capsules and the self-healing ability of coatings with microcapsules. Capsule formation with large amounts of glycerol gave rise to clusters of capsules, while with small amounts of glycerol, the capsules were mainly independent. The self-healing property of the coatings was more remarkable with a decreasing amount of glycerol in the capsule formation process. [ABSTRACT FROM AUTHOR]