Brief introduction of organosilicon modification and organofluorine modification


Because of the main chain and side chain of organic structure in the structure of organosilicon, organosilicon has the dual characteristics of organic and inorganic. The water-borne polyurethane (WPU) modified by this material can improve the high and low temperature resistance, water resistance, oil resistance and chemical stability of the water-borne polyurethane curing film, and make it have excellent adhesion performance. Therefore, in order to improve the performance of waterborne polyurethane, it is very valuable to study the modification of organosilicon materials.


Waterborne polyurethane modified by hydroxyl silicone oil and silane as composite coupling agent was prepared and prepared with excellent water resistance emulsion after modification. The water absorption rate of the modified waterborne polyurethane emulsion decreased significantly, elongation at break decreased significantly, tensile strength increased, and the surface of the waterborne polyurethane emulsion was softer and slippery, showing better comprehensive properties.


Polyether polysiloxane diols (PESO), isophorone diisocyanate (IPDI), polyether 210, DMPA and three hydroxymethyl propane (TMP) were used as the main raw materials, and a self crosslinking silicone modified waterborne polyurethane (Si-WPU) emulsion was synthesized by prepolymer method. The emulsion was used to study the effect of different dosage of PE-SO on the properties of modified PU emulsion and its film. The results showed that when the mass fraction of PE-SO was 6%, the Si-WPU emulsion had good stability and small particle size, and the water resistance and mechanical properties of the film reached the best effect.


To sum up, Si-WPU emulsion has the advantages of increased water resistance, low elongation at break, and increased tensile strength.


Due to the small radius of fluorine atom, strong electronegativity, small polarizability and refractive index, fluoropolymer has excellent electrical and optical properties, which can be used to improve water resistance, reduce water absorption, improve chemical resistance and weather resistance of waterborne polyurethane. Because of the excellent properties of the fluorine-containing polyurethane with water as the dispersion medium, it is of great significance to study the modification of the organic fluorine material in improving the properties of the waterborne polyurethane.


Aqueous polyurethane modified with eight fluoroprene alcohol (F8) as modifier was used to synthesize waterborne polyurethane (FWPU) containing fluorine based materials. The structure of FWPU was characterized by Fourier transform infrared spectroscopy (FTIR), and the effect of F8 content on the properties and film properties of waterborne polyurethane emulsion was studied. The results showed that: with the addition of F8, the water resistance of the coating increased significantly, and when the amount of F8 was 8%, the water absorption rate of the coating decreased from 3.1% to 3.1%, and the contact angle increased from 80 to 108 degrees. The diameter of the emulsion increased first and then decreased. When the F8 content was added to 4%, the emulsion particle diameter reached the maximum of 157 nm. TGA test results show that the thermal stability of the modified fwpu film is significantly improved.


To sum up, organic fluorine modified waterborne polyurethane can make the emulsion have excellent water resistance and thermal stability.


Source: anda Huatai