Performance and Application of Double-layered Microcapsule Corrosion Inhibitors

• Published in: Journal of Wuhan University of Technology. Materials science edition 2024-08, Vol.39 (4), p.845-853
• Main Authors: Yu, Haiyan, Wang, Yingxiang, Wang, Ruizhi, Hu, Lintong, Wang, Tianlei
• Format: Article
• Language: English
• Subjects: Advanced Materials; Chemistry and Materials Science; Concrete; Corrosion effects; Corrosion inhibitors; Corrosion potential; Corrosion prevention; Materials Science; Membrane structures; Membranes; Microencapsulation; Microscopy; Monolayers; Mortars (material); Particle size distribution; Polymethyl methacrylate; Polyvinyl alcohol; Service life; Sodium fluorophosphate; Spray drying; Thermal stability
• ISSN: 1000-2413; 1993-0437
• DOI: 10.1007/s11595-024-2945-z

Double-layered microcapsule corrosion inhibitors were developed by sodium monofluorophosphate as the core material, polymethyl methacrylate as the inner wall material, and polyvinyl alcohol as the outer wall material combining the solvent evaporation method and spray drying method. The protection by the outer capsule wall was used to prolong the service life of the corrosion inhibitor. The dispersion, encapsulation, thermal stability of microcapsules, and the degradation rate of capsule wall in concrete pore solution were analyzed by ultra-deep field microscopy, scanning electron microscopy, thermal analyzer, and sodium ion release rate analysis. The microcapsules were incorporated into mortar samples containing steel reinforcement, and the effects of double-layered microcapsule corrosion inhibitors on the performance of the cement matrix and the actual corrosion-inhibiting effect were analyzed. The experimental results show that the double-layered microcapsules have a moderate particle size and uniform distribution, and the capsules were completely wrapped. The microcapsules as a whole have good thermal stability below 230 °C. The monolayer membrane structure microcapsules completely broke within 1 day in the simulated concrete pore solution, and the double-layer membrane structure prolonged the service life of the microcapsules to 80 days in the simulated concrete pore solution before the core material was completely released. The mortar samples containing steel reinforcement incorporated with the double-layered microcapsule corrosion inhibitors still maintained a higher corrosion potential than the monolayer microcapsule corrosion inhibitors control group at 60 days. The incorporation of double-layered microcapsules into the cement matrix has no significant adverse effect on the setting time and early strength.