The text describes the chemical composition analysis and thermal stability analysis of microcapsules containing ODA (octadecyl amine) and EC (epoxy resin). The Fourier Transform Infrared (FT-IR) spectra of the microcapsules, EC, and ODA are compared to confirm the encapsulation of ODA in the EC. The thermal stability analysis shows that the microcapsules begin to decompose at around 100°C, with a second decomposition peak around 268°C.
The morphological analysis of the microcapsules shows that they are spherical and have a smooth surface, allowing for better encapsulation of ODA. The particle size distribution shows that most of the microcapsules are between 100-120 μm in diameter.
The corrosion resistance of the self-healing coatings is also evaluated. The results show that the coatings with 6 wt% addition amounts of microcapsules have better corrosion resistance than those with other addition amounts. The corrosion resistance is further improved by adding microcapsules to the epoxy coatings, as shown by the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve results.
The self-healing coatings are also tested for their ability to repair cracks and scratches. The results show that the self-healing coatings can effectively repair cracks and scratches, while the pure epoxy coatings cannot. The self-healing mechanism is attributed to the adsorption of ODA on the metal surface, which forms a hydrophobic film and prevents corrosion.
Overall, the results suggest that the microcapsules containing ODA and EC are effective at improving the corrosion resistance and self-healing properties of the coatings. The ODA acts as an adsorption corrosion inhibitor, forming a hydrophobic film on the metal surface and preventing corrosion. The EC provides a matrix for the encapsulation of ODA, protecting it from degradation and allowing it to be released and adsorbed on the metal surface as needed. The combination of ODA and EC results in a coating with improved corrosion resistance and self-healing properties.