Synthesis and characterization of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains

The dispersion of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains (FPUA) terminated with pentaerythritol triacrylate (PETA) was synthesized by incorporating fluorine groups into the side chains of the polyurethane macromolecular from condensation polymerization by using perfluorooctanoate glycerate (OF-diols) as chain extender, while the polyurethane macromolecular was synthesized from isophoronediisocyanate (IPDI), dimethylol propionic acid (DMPA), and poly (propylene glycol) (PPG) etc. The chain extender was prepared from 2,2-dimethyl-1,3-dioxolane-4-methyl perfluorooctanoate (OF-diols-pg) by acid hydrolysis with trifluoroacetic acid. The structure of FPUA was characterized by FTIR, NMR, elemental analysis, UV–vis and Mass spectra, and the properties of the synthesized FPUA emulsion were also discussed. The effect of fluorine content on the UV-curing dynamics was studied and the UV-curing speed decreased with increment in fluorine content. Contact angle measurements shown that the hydrophobic property of the surface greatly increased by incorporation of fluorine into the polyurethane chain. In addition, scanning electron spectroscopy (SEM) analysis was applied to characterize the morphology of the fracture surface of the UV-cured FPUA which became phase-mixed after annealing.