Preparation of Core-Shell Emulsion Functional Anticorrosive Coating Based on Vinyl Phosphonic Acid

Aluminum and its alloys have a wide range of applications because of their excellent properties. However, aluminum corrodes during actual use. Therefore, protecting aluminum is usually achieved through coatings. Due to environmental protection requirements, the research of water-based coatings is becoming more and more important. This paper reported the preparation of functional latex particles containing phosphonic acid with core-shell structure using styrene (St) and n-butyl acrylate (BA) as copolymers and vinyl phosphonic acid (VPA) as the functional monomer. The core-shell structure was accomplished through seed emulsion polymerization, using poly(St-co-BA) as the seed and poly(St-co-BA-co-VPA) as the shell. The core-shell emulsions a solid content (mass fraction of solid particles in the emulsion product) of approximately 30%, uniform particle distribution, and a well-defined core-shell structure. The coatings exhibited a thermal decomposition temperature above 380 ℃. The corrosion potential of the coating could reach 1.74 V, the corrosion current density also decreased, and the corrosion resistance was excellent, which proved the excellent corrosion resistance of aluminum. In electrochemical impedance spectroscopy tests, this functional coating had a high impedance, which also proved that this coating could greatly slow down the corrosion rate.