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

Abstract

a b s t r a c tNovel 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 m 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.

Mechanical and self-healing properties of a water-based acrylic latex containing linseed oil filled microcapsules: Effect of pre-silanization of microcapsules' shell compound

“…The observed fluctuation in the mechanical properties at higher microcapsules loading may be attributed to an undesirable dispersion of the microcapsules and in turn to the presence of aggregates, air pockets as well as discontinuity. Similar results have been also observed in other microcapsules-containing coating systems [19,21].…”

“…However, this effect was less pronounced for the latex films containing microcapsules and in particular, microcapsules with pre-silanized shell have shown better restoring the mechanical properties of latex films after pre-elongation. These results revealed that the oil may be released from the microcapsules under mechanical stresses lower than yield point in the surrounding polymeric matrix and caused the slipping polymer chains on each other; thereby elongation of latex film increased [12,21]. These results support that the released oil increased elongation at break and decreases Young's modulus.…”

“…These results clearly show that mechanical properties of the samples relatively restored after crack filling by released oil. After the crack creation on the coating's surface, the oil instantly released from the ruptured microcapsules and rather filled the crack area [31]. The atmospheric oxygen then oxidized the released oils and therefore, sealed the crack region on the coating's surface.…”

Sunlight‐Activated Self‐Healing Polymer Coatings

“…Micro‐ or nanocapsules have also been used as an additive to repair the damage and restore the barrier properties of the original coating. Microencapsulated self‐healing bulk polymers have been widely reported . When a crack is introduced to the polymer, microcapsules are ruptured and their core contents are released into the damage.…”

Effect of Urea-Formaldehyde-Coated Epoxy Microcapsule Modification on Gloss, Toughness and Chromatic Distortion of Acrylic Copolymers Waterborne Coating

“…Zhang et al prepared microcapsule-based self-healing coatings containing epoxy ester as a healing agent [15]. Mirabedini et al prepared self-healing acrylic latex coatings using novel oil-filled ethyl cellulose microcapsules with enhanced mechanical properties and healing properties of latex coating [16]. Ataei et al found that the gloss and bond strength of the coatings decreased and the flexural elongation decreased with the increase of the concentration of microcapsules in epoxy coating containing microencapsulated alkyd resin based on coconut oil [17].…”