Preparation of self-healing acrylic latex coatings using novel oil-filled ethyl cellulose microcapsules

• Oil-filled microcapsules were prepared using a novel phase separation method.
• Latex films containing rapeseed oil-filled microcapsules were prepared.
• Addition of oil-filled microcapsules improved tensile properties of the films.
• Colorimetric measurements were used to study self-healing mechanism of films.
• Self-healing and tensile properties of films enhanced via plasticizing mechanism.

Novel oil-filled microcapsules were prepared by introducing a phase separation method using ethyl cellulose as a shell-forming containing rapeseed oil. The prepared oil-filled microcapsules were evaluated by optical microscopy, scanning electron microscopy and particle size analysis. Results showed that spherical microcapsules with a diameter of 10 to 45 μm and a rough porous shell were obtained. Carboxylated styrene/butadiene copolymer latex films containing various levels of these microcapsules were subjected to various levels of pre-elongation and their tensile properties were examined. The addition of oil-filled microcapsules resulted in a significant improvement in the modulus, strain-to-break, and toughness of the films. The self-healing mechanism of latex films was examined through the colorimetric measurements of the release of dye-containing following the pre-elongation of the samples. These measurements confirmed that pre-elongation of samples resulted in the release of oil within the latex films, hence plasticizing the surrounding polymeric network and partly restoring the mechanical properties of the pre-elongated films.

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