Preparation and Characterization of the Cross-Linked Fluoro-Silicon Polyacrylate–Polyurethane Hybrid Emulsions for Superior Performance of Waterborne Coatings

This work focuses on the problem-solution of the weak mechanical properties, low water and corrosion resistances encountered in waterborne hydroxyl acrylic resin (WA) by low surface energy modification, and the construction of cross-linking structure. A waterborne hydrophobic hydroxyl acrylic resin (WFSA) with core–shell structure was first synthesized by the emulsion polymerization technique using acrylate monomers as the main materials and 3-(methacryloyloxy)propyltris(trimethbylsilyloxy) silane (M 3 T) and 2-(perfluorooctyl)ethyl methacrylate (FMA) as modified monomers. Then, different contents of hydrophilic polyisocyanate cross-linking agent (XP2655) were introduced into WFSA to obtain the cross-linked coatings (CFSAUs). The results showed that the comprehensive properties of CFSAUs are mainly determined by the hydrophobicity of the resin matrix and the cross-linking degree between WFSA and XP2655. The cross-linking density, the water absorption, the water contact angle, and the tensile strength of the optimal CFSAU-8 coatings are 11.75 × 10 –4 mol/cm 3, 5.64%, 110.1°, and 6.14 MPa, respectively. Moreover, CFSAU-8 not only possessed better thermal stability when compared with WA and WFSA but also maintained a low frequency (0.01 Hz) impedance modulus, being larger than 10 6 Ω cm 2 even after immersion in 3.5 wt % NaCl solution for 15 days. CFSAU-8 coating is possibly qualified to be applied in waterproof and corrosion protection fields.