Synthesis and characterization of waterborne polyurethane modified by fluorinated polysiloxane used for fabric coating

For the synthesis of high-performance fabric coating agents, water-borne polyurethanes modified by polysiloxane (WFSPU) were prepared by polyaddition reaction using poly (tetramethylene oxide)glycol, polyethylene glycol and amino fluorinated polysiloxane (AFS) as mixing soft segments. The chemical composition of modified polyurethane was characterized using infrared spectroscopy and nuclear magnetic resonance spectroscopy. The emulsion stability was studied by the use of nano-particle size and Zeta potential analyzer. Thermal properties, free volume hole and mechanical properties of WFSPU film were investigated by differential scanning calorimetry, positron annihilation spectroscopy and static tensile test. The results show that stable emulsion can be obtained when the amount of AFS (mass fraction) <10%. Soft segment glass transition temperature of polyurethane film is about -78°C. When the mass fraction of AFS is 6%, the tensile modulus of polyurethane films is up to 47.33 MPa, while the break elongation is 663.49%.