The self-healing evaluation of microcapsule-based epoxy coatings applied on AA6061 Al alloy in 3.5% NaCl solution

Abstract

Purpose The aim of this work is to investigate the self-healing performance of epoxy coatings containing microcapsules. The microcapsule-based coatings were applied on AA6061 Al alloy and immersed in 3.5 per cent NaCl solution. Design/methodology/approach Microcapsules with urea–formaldehyde as the shell and linseed oil as the healing agent were prepared by in situ polymerization in an oil-in-water emulsion. For the sake of an optimum self-healing system, some coating samples were prepared by using different microcapsule concentrations: 0, 5, 10 and 20 Wt.%. The scratch-filling efficiency as the theoretical estimate of the self-healing performance was calculated for the coating samples with different microcapsule concentrations. The scratch-sealing efficiency (SSE) as a particularly crucial parameter in the self-healing evaluation of coatings was measured by both electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. Findings According to EIS and EN results, the coating samples containing 5 and 10 per cent microcapsules provided the insignificant self-healing performance, while the coating sample containing 20 per cent microcapsules exhibited the acceptable self-healing performance to AA6061 alloy in the NaCl solution. The measured SSE values confirmed the good agreement of EN data with electrochemical parameters obtained from the EIS technique. Originality/value This work is an attempt to evaluate the self-healing performance of microcapsule-based epoxy coatings applied on AA6061 Al alloy in sea water.

Octylamine-Modified Cellulose Nanocrystal-Enhanced Stabilization of Pickering Emulsions for Self-Healing Composite Coatings

“… 39 − 48 These UF–linseed oil microcapsule systems presented both self-healing and anticorrosive properties with healing times varying from 2 days to 30 days and healing temperatures from room temperature to 80 °C. 41 − 45 , 48 A self-healing hydrogel containing CNC (extracted by ethanedioic acid hydrolysis) and linseed oil has also been recently published. 49 …”

“…39−48 These UF−linseed oil microcapsule systems presented both self-healing and anticorrosive properties with healing times varying from 2 days to 30 days and healing temperatures from room temperature to 80 °C. [41][42][43][44][45]48 A self-healing hydrogel containing CNC (extracted by ethanedioic acid hydrolysis) and linseed oil has also been recently published. 49 However, no CNMs have been investigated with their efficacy to emulsify linseed oil, nor the fabrication of sustainable self-healing coatings using these materials.…”

Effect of Shellac Waterborne Coating Microcapsules on the Optical, Mechanical and Self-Healing Properties of Waterborne Primer on Tilia europaea L. Wood

“…Wang et al [17] prepared self-healing coating by adding 10.0% concentration of microcapsules into an epoxy polyamine coating matrix, and explored the effect of microcapsules on the corrosion resistance of the self-healing coating. Mixing microcapsules into the coating will have a certain impact on the performance of the coating [18,19]. The more microcapsules are added, the better the repair effect is, but an excessive amount of microcapsules will affect the optical [20], mechanical [21], liquid and aging resistance [22] of Tilia europaea L. paint film.…”

Effect of Coating Process on Mechanical, Optical, and Self-Healing Properties of Waterborne Coating on Basswood Surface with MF-Coated Shellac Core Microcapsule

“…The performance of waterborne coating on the wood surface was not only affected by the content of the microcapsules added into the coating, but also by the coating process. This is an important factor that cannot be ignored [ 23 ]. In order to further determine the self-healing mechanism of waterborne coating, the coating times of primer and finish, and whether adding microcapsules in the primer or finish has an impact on the performance of the coating was examined.…”