Microcapsules with linseed oil and benzotriazole
A new study describes the anticorrosion and healing properties of an epoxy coating with poly(urea–formaldehyde) microcapsules encapsulated linseed oil and benzotriazole.
Two-component microcapsules were prepared with benzotriazole (BTA) and linseed oil as the core material and poly(urea–formaldehyde) as the shell material. The effects of stirring speed, temperature, type and amount of emulsifier, core/shell mass ratio, and initial pH on the microcapsule structure and properties were studied, and the optimal preparation process of the two-component microcapsules was obtained. On this basis, the shell stability of the microcapsules was enhanced by adding graphene oxide (GO), and the added content of GO was optimised by means of microscopic observation.
Anticorrosion performance
The results show that the optimal preparation process of the two-component microcapsules is as follows: The stirring speed is 500 r/min, the temperature is 55°C, the amount of polyvinyl alcohol is 5 g, core/shell mass ratio is 1.25:1, the initial pH is 3, the added amount of GO is 0.3 wt%, and the encapsulation rate of the prepared microcapsules was as high as 83.44%. Subsequently, different contents of graphene-based two-component microcapsules were embedded into the epoxy coating, and the best ones were optimised by self-healing performance test (scratch test) and anticorrosion performance test (salt spray test and electrochemical impedance spectroscopy). The experimental results show that the impedance modulus of the damaged graphene-based two-component self-healing coating after repair can reach 1.29 × 109 Ω cm2, and the repair process can last for 24 h.
The study has been published in Journal of Coatings Technology and Research, Volume 20, Issue 6, November 2023.
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