Synthesis, Characterization and Corrosion Resistance Behavior of Waterborne Cationic Acrylic Resins

Cationic acrylic resins with different glass transition temperatures (Tg) and molecular weight (Mw) were synthesized using different ratios of methyl methacrylate (MMA) and tertiary butyl acrylate (TBA) monomers. Furthermore, waterborne acrylic coatings were prepared using the cathodic electrocoating application technique. The cathodic electrocoating process was carried out at 80 V for 120 seconds to obtain a dry film thickness of 20±2 μm. Fourier transform infrared spectroscopy (FTIR), GPC (molecular weight), glass transition temperature, particle size, zeta potential, and viscosity measurements were used to characterize the synthesized cationic acrylic resin. The throwing power (ability to coat recessed area) and cross-cut adhesion were evaluated for each resin. According to the electrochemical impedance spectroscopy (EIS) data and general properties, the coatings with an MMA/TBA ratio of 0.125 exhibited excellent corrosion resistance (Log |Z|0.01Hz stay above seven even after 720 hours dipping in 3.5 wt.% NaCl solution). By increasing the MMA/TBA ratio, the final product's average molecular weight and viscosity were increased.