Preparation Of Nanocomposites Based On Waterborne Polyurethane And Study On Its Electrorheological Performance

In order to study the preparation, the characterization and the performance on bond, ultraviolet (UV) curable water-borne polyurethane resin and electrorheological(ER) systems of waterborne polyurethane composites, the structure-property relationships of polyurethane ionomers and their nanocomposites were studied carefully by difference modified measurements.In this paper, the visualized optimization method was used to guide the design of experimental formula innovatively, and the waterborne polyurethane emulsion with double modification was synthesized with acrylate and tri-methylolp ropane (TMP) as the cross-linkers as well as with epoxy resin (EP) and acrylate as the modification agents. In this study, two sets of EP/WPU emulsions of various EP contents were synthesized with include chemical graft method and physical blend method. The structure and properties of the modified emulsion was also characterized using Fourier Transform Infrared (FT-IR), Transmission Electron Microscope (TEM), Differential Scanning Calorimetry (DSC), Particle Size Analyzer and Stretching Measurement. The different mechanical properties between before and after the UV irradiation of the PU films, the different way of filling EP, and the different EP content were compared respectively.We focused on the preparation of anionic silicon dioxide/polyurethane (SiO2/PU) which was synthesized by in-situ hydrolyzation and phase-reversion. Comparison the structure and the properties of different samples, the electrorheological (ER) characteristic of SiO2/PU which was prepared by in-situ hydrolyzation were focused on.The experimental results showed that silicon dioxide can enhance the toughness and the strength of the WPU films. The double modification can strengthen the heat resistance and the water resistance. When the content of reactive diluent is between 30% and 50%, the content of photoinitator is 3%, and the UV-curing time is 60s, the property of the UV-curing film is the best. For the waterborne polyurethane modified by epoxy resin system, chemical grafting is more difficult than mechanical blending to prepare stable emulsion. The tensile strength and the elongation increased significantly, and the particle size distribution was broadbanding along with the the amount of epoxy resin increase. The ER property of the SiO2/PU was characterized. The ER activity is obviously higher for the more SiO2 content samples in a constant electric field. The sample made of HDI has better ER effect than the sample made of MDI in the same electric field at the same shear rate.