Studies on waterborne polyurethanes based on new medium length fluorinated diols

• WPU with fluorinated medium branched chain were synthesized.
• Water/solvent resistance, thermal and mechanical properties of WPU were improved.
• Effect of physical properties on WPU with fluorine content was well studied.
• This study opens a window to produce high-performance polyurethane materials.

A novel fluorinated diol 3-(bis-(N,N-dihydroxyethyl)) dodecafluoroheptyl acrylate (DEFA) was for the first time synthesized via Michael addition reaction between diethanolamine and dodecafluoroheptyl acrylate, followed by a series of waterborne fluorinated polyurethane emulsions IPDI-DEFA-PU synthesis using isophorone diisocyanate (IPDI), poly(tetramethylene oxide glycol) (PTMG), dimethylolpropionic acid (DMPA) and 1,4-butanediol (BDO) as main starting materials, and DEFA as a chain extender. The structure of DEFA and IPDI-DEFA-PU was confirmed by Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (1H NMR). It was found that the fluorine content increased from 0 to 15.1%, and the particle size of emulsion increased from 102 nm to 260 nm, whereas the surface tension of latex film decreased from 42.9 mN/m to 16.5 mN/m; while the water contact angle increased from 71° to 104°, the swelling ratio of latex film in water and cyclohexane decreased from 15.8% to 1.1% and from 28.8% to 3.4%, respectively. Meanwhile, water/organic solvent resistance and thermal stability, mechanical properties of IPDI-DEFA-PU were all improved. As tensile strength increased from 9 MPa to 15 MPa, extensibility decreased from 520% to 280%.

The water/organic solvent resistance, thermal stability and mechanical properties of the resulting fluorinated waterborne polyurethanes were all improved. It was found that the fluorine content increased from 0 to 15.1%, and the tensile strengths increased from 9 MPa to 15 MPa, whereas the extensibility decreased from 520% to 280%.Figure optionsDownload as PowerPoint slide