Vinyl-capped cationic waterborne polyurethane (CWPU) was prepared using isophorone diisocyanate (IPDI), polycarbonate diol (PCDL), N-methyldiethanolamine (MDEA), and trimethylolpropane (TMP) as raw materials and hydroxyethyl methacrylate (HEMA) as a capping agent. Then, a crosslinked FPUA composite emulsion with polyurethane (PU) as the shell and fluorinated acrylate (PA) as the core was prepared by core-shell emulsion polymerization with CWPU as the seed emulsion, together with dodecafluoroheptyl methacrylate (DFMA), diacetone acrylamide (DAAM), and methyl methacrylate (MMA). The effects of the core-shell ratio of PA/PU on the surface properties, mechanical properties, and heat resistance of FPUA emulsions and films were investigated. The results showed that when w(PA) = 30~50%, the stability of FPUA emulsion was the highest, and the particles showed a core-shell structure with bright and dark intersections under TEM. When w(PA) = 30%, the tensile strength reached 23.35 ± 0.08 MPa. When w(PA) = 50%, the fluorine content on the surface of the coating film was 14.75% and the contact angle was as high as 98.5°, which showed good hydrophobicity; the surface flatness of the film was observed under AFM. It is found that the tensile strength of the film increases and then decreases with the increase in the core-shell ratio and the heat resistance of the FPUA film is gradually increased. The FPUA film has excellent properties such as good impact resistance, high flexibility, high adhesion, and corrosion resistance.
Keywords: acrylate-based composites; cationic waterborne polyurethane; core-shell structure; isocyanate reactivity; tensile strength.