Optimization of the branched structure to enhance the corrosion protection of waterborne acrylic-alkyd resins on iron-based materials.

Waterborne acrylic-alkyd resins with various acrylic resin contents were synthesized by free-radical polymerization on the alkyd resin side chains to produce copolymers with different molecular structures on the side chains to improve the coating corrosion protection properties. By copolymerizing the double bonds introduced on the alkyd resin with acrylic monomers and designing the side-chain structure of the alkyd resin, a denser crosslinking structure of the coatings can be achieved. This improves the thermal stability and corrosion resistance of the coatings. The denser crosslinked network is achieved by the flexibility of the highly branched acrylic resin and copolymer chains grafted on the side chains, making it more difficult for corrosive media to pass through the contact between the coating and the tinplate substrate. Gel permeation chromatography with thermogravimetric and electrochemical analyses showed that the highly branched side-chain structure enhanced the thermal stability and corrosion resistance of the coated samples compared to the small-molecule side-chain structure of the copolymers. This work illustrates that coating corrosion protection can be improved by optimizing the side-chain structure. • Waterborne acrylic-alkyd resins with different side-chain molecular structures were synthesized by free-radical polymerization to enhance corrosion resistance. • Acrylic acid was successfully grafted onto the side chain of alkyd resin by esterification reaction. • The improvement of the molecular structure of the side chains enhanced the water resistance, thermal stability and corrosion resistance of the resins. • A method to improve the anti-corrosion properties of coatings by optimizing the side-chain structure is described. [ABSTRACT FROM AUTHOR]