The synthesis of hyperdispersants with different anchoring and solvated segments for improving the dispersion of mica in UV-curable anti-corrosion coatings
摘要
In this article, a series of acrylic ester copolymer hyperdispersants with different chemical structures (anchoring segments and solvated segments) were designed and synthesized by free radical polymerization and used to disperse mica in UV-curable systems. The influence of anchoring segments and solvated segments of the polyacrylic hyperdispersant on the dispersion of mica in UV-curable coating as well as the coating properties was systematically investigated. The dispersion performance of the hyperdispersants was investigated by rheology measurement, mechanical property, and anticorrosion property (via electrochemical impedance spectroscopy and neutral salt spray test) of the UV-curable coatings. It was found that the optimum anchoring segment and solvated segment of the polyacrylic hyperdispersant for dispersing mica in UV-curable systems were N-isopropylacrylamide (NIPAM) and butyl methacrylate (BMA), respectively. With the addition of p(BMA-co-NIPAM), the viscosity of the UV-curable resin system with mica decreased obviously. Moreover, the negative effect of mica on the mechanical properties of the UV-curable coatings was significantly mitigated, and the coating exhibited outstanding anticorrosion performance. The electrochemical low-frequency impedance value of the coating remains above 109.0 Ω cm2 for 40 days without any decrease. After 1,200 h of neutral salt spray testing, only slight pitting corrosion was observed on the coating surface.