High Performance Self-Healing Epoxy/Polyamide Protective Coating Containing Epoxy Microcapsules and Polyaniline Nanofibers for Mild Carbon Steel

Abstract

Epoxy microcapsules and polyaniline nanofibers are incorporated into epoxy/polyamide coatings to enhance the protective and self-healing performance of the coatings for mild carbon steel. Epoxy microcapsules are prepared through the wellknown interfacial polymerization process. Sodium chloride (NaCl, 12 wt %) solution is used as the model corrosion media. Protective and self-healing performance of the coatings is characterized by the electrochemical impedance spectroscopy (EIS) technique, scanning electron microscope (SEM) image analysis, and X-ray photoelectron spectroscopy characterization. The results demonstrate that the coatings containing epoxy microcapsules and polyaniline nanofibers have almost no deterioration in the 100-day testing period under the condition of being immersed in 12 wt % NaCl solutions at room temperature. The excellent protective performance and self-healing behavior are ascribed to the controlling release of epoxy which is encapsulated and the passive property of PANI nanofibers. The results might give some insights on the preparation of high performance protective coatings.

Electrochemical impedance spectroscopy (EIS): An efficiency method to monitor resin curing processes

“…The first one is the polymerization reaction between epoxy groups and amino groups, and the second one is the polymerization reaction between epoxy resin molecules under the alkaline condition [24]. The curing reactions are complex processes, along with the variation of viscosity, conductivity, dielectric properties and so on.…”

A review of advances in the preparation and application of polyaniline based thermoset blends and composites

“…The first method for the preparation of anticorrosion coatings is proposed by Zhang et al, in which a coating of PANI nanofibres mixed with the selfhealing epoxy microcapsules is included as an additive to the epoxy/polyamide composite. This system shows very high efficient protective anticorrosive coating when applied on mild steel [94]. In the second approach towards protective coatings application, a layer PANI is applied as a primer in the surface of PANI-thermoset stratified assembly.…”

‘Containers’ for self-healing epoxy composites and coating: Trends and advances

“…Coating with an optimum concertation of epoxy microcapsules (20 wt%) completely healed the scratched surface with in 4 hrs. Also, these epoxy microcapsules were later used in epoxy/polyamide coatings for mild carbon steel for self-healing performance along with polyaniline nanofibers for passive property [54]. In epoxy protective coatings, solvents used to lower resin viscosity and heat treatment used to remove solvent or to cure coating matrix adversely affect the stability of the microcapsules.…”