Development of Self-Healing 2 K Waterborne Polyurethane Coatings with PVA/Polyurea Microcapsules for Enhanced Corrosion Protection

The article investigates the development of self-healing 2K waterborne polyurethane (WPU) coatings enhanced with PVA/polyurea microcapsules, focusing on their superior corrosion protection properties. The study begins with an overview of the evolution of polyurethane coatings, highlighting their transition from traditional protective and decorative applications to multifunctional systems. The core of the research lies in the synthesis of PVA/polyurea microcapsules loaded with isophorone diisocyanate (IPDI) using interfacial polymerization. The microcapsules are characterized using techniques such as FT-IR, TGA, SEM, and EIS to evaluate their structure, thermal stability, and self-healing performance. The article also explores the impact of different PVA grades on the microcapsules' properties, revealing that the degree of polymerization and alcoholysis of PVA significantly influences the microcapsules' size, morphology, and thermal stability. The self-healing mechanism of the coatings is elucidated through electrochemical impedance spectroscopy and SEM analysis, demonstrating the effectiveness of the microcapsules in repairing cracks and enhancing corrosion resistance. The study concludes with a detailed evaluation of the coatings' performance, highlighting the optimal concentration of microcapsules for achieving the best balance between mechanical properties and self-healing efficiency. The findings suggest that the developed 2K WPU coatings with PVA/polyurea microcapsules offer a promising solution for long-term durability and enhanced corrosion protection in harsh environments.