Preparation and properties of polysiloxane modified fluorine-containing waterborne polyurethane emulsion

A series of polysiloxane modified fluorinated waterborne polyurethane emulsions (H-SiFPU) were prepared by using hydroxypropyl polydimethylsiloxane (HP-PDMS) and polytetramethylene ether diol (PTMG) as soft segments, isophorone diisocyanate (IPDI), dihydroxymethyl butyric acid (DMBA), 2,2,3,3,4,4,5,5-octafluoro-1-pentanoloctafluoropentol (OFP) and ethylenediamine (EDA) as hard segments. The structure and properties of the emulsion were characterized by FT-IR, TG, SEM, XPS, XRD, water absorption and contact angle. The results show that with the increase of the dosage of HP-PDMS, the particle size trends to firstly increase and then decrease, and the transmittance of the emulsion gradually decreases. Moreover, the addition of HP-PDMS increases the thermal stability and phase separation of the film and reduces the crystallization property. The fluorine and silicon elements are enriched on the surface of the film, the water contact angle increases from 71.2°to 105.95°, and the water absorption decreases from 20.3% to 11.1%, which contributes to the water resistance of the film. Therefore, it is concluded that with the addition of 15 wt% HP-PDMS, the tensile strength and tear strength of coated leather are 935N and 130N, respectively. Meanwhile, the coated leather has excellent hydrophobicity, good aging resistance and mechanical properties.