Research Of Nano-Modified Waterborne Polyurethane

In this paper, nano-SiO2 and nano-TiO2 particles were respectively modified by toluene diisocyanate (TDI) and polyethylene glycol (PEG). The results of sedimentation test, grain size analysis and SEM image showed that the dispersibility of the modified nano-SiO2 and nano-TiO2 particles were improved, The results of FTIR and TG showed that TDI and PEG were successfully grafted onto the surface of nanoparticles.when molar ratio of TDI to PEG was 1:0.8, the nanoparticles has highest rate of organic grafting and good distribution in ethanol.Waterborne Polyurethane emulsion was prepared by prepolymer mixing proeess. The effeets of the synthesis process and ratio of material on the properties of emulsion and film were researched, and the best synthesis was determined.nano-particle/polyurethane emulsion was preparaed by blending method. SEM photo shows that nanoparticles were well dispersed and no agglomerates can be observed. Through the test of the resin viscosity, water absorption, acid resistance, hardness, tensile strength and elongation and other properties,the test results showed that the mechanical properties were improved by adding nanoparticles. When the contents of SiO2 and TiO2 were up to 0.5%, the waterborne polyurethane can provide.the best mechanical properties. The adhesion was 0 level, the tensile strength was 26MPa, the elongation at break was 971%, the pencil hardness was 2H, coating water resistance and acid resistance were improved.