To improve the corrosion resistance of waterborne polyacrylate latexes coatings, an epoxy/polyacrylate (EP/PA) composite latex with high EP content was developed viaminiemulsion polymerization as the matrix of anticorrosion coatings. Transmission electron microscopy illustrated that the EP/PA composite had spherical shapes with the diameter of 130–199 nm. In addition, differential scanning calorimeter and thermal gravity analysis thermograms suggested that the EP/PA composites showed good compatibility and thermal stability. The barrier properties of the EP/PA composite coatings were also remarkably enhanced by the crosslinking between EP groups and primary amines during film formation. Moreover, the use of phosphate emulsifier could act as an adhesion promoter to form a passive layer to prevent metals from further corrosion. The corrosion resistance of EP/PA composite coatings on cold-rolled steel was fully investigated by the Tafel polarization test, salt spray test, and scanning electron microscope. The Tafel polarization test results show that the EP/PA composite coatings exhibited a low corrosion rate of 1.2 μm per year, which was better than the PA coatings by a factor of 24. Therefore, the obtained EP/PA composites could significantly improved the corrosion resistance of waterborne polyacrylate latexes, and showed a great potential application in the aqueous metal coatings.
Volume 113, December 2017, Pages 143–150