| Aqueous polyurethane as an environment-friendly material has attracted greatly attention. In this thesis, a series of modified anion aqueous polyurethanes (PU) were synthesized. The relationship between structure and properties was investigated, and modifying mechanism was also discussed. The main contents of this thesis include the following points:1. The development and applications of aqueous polyurethane were reviewed, and the preparation methods of aqueous polyurethane were also summarized in detail.2. The optimal preparation conditions of anion aqueous polyurethanes (PU) were investigated. The modified aqueous polyurethanes were prepared based on three different methods. (1) Siloxane hydrolysis crosslinking method. The modified polyurethanes (PU-Si) were prepared by the reaction with prepolyurethane and hydrolysis cross-linking of 3-aminotriethoxysiliane. (2) Acrylate copolymerization. The end-capped polyurethanes is copolymerized with acrylic monomers (methylmethacrylate, MMA, and butylacrylate, BA) to obtain the acrylate cross-linking modified polyurethane (PUA). (3) Combined modification method to prepare polyurethane (PUA-Si). The polyurethane is modified from a combination of siloxane hydrolysis cross-linking method and acrylate copolymerization method.3. The modified polyurethanes were characterized by IR, DSC, TEM and their performances were investigated by measuring tensile strength, pencil hardness, water absorption and TGA. The relationship between structure and properties was discussed in detail. The results show that the modified PU possesses better performance than PU. Simultaneously, it is found that the KH550 weight percent has a great effect on the stabilization of PU-Si emulsions, while the PUA emulsion has better stabilization than that of PU-Si. In all the three modified polyurethanes, PUA-Si prepared from the combined method displayed best properties. The pencil... |
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