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Waterborne polyurethane not only with solvent-based polyurethane with high strength and excellent properties of wear-resistant and safe to use, non-toxic, easy to process operations, non-flammable, easy to store, and environmental pollution, which has received considerable attention. However, since the emulsified water-based polyurethane due to the limitations of the synthesis conditions, the polymer is relatively low molecular weight, molecular side chains exist more hydrophilic groups, resulting in its poor mechanical properties and water resistance of the film, which to some extent limit the scope of its application. In recent years, a large number of studies show that the the crosslinking modification is to improve the film properties of the aqueous polyurethane is the most direct and most effective way. The ketone carbonyl group is introduced into the molecular chains in the aqueous polyurethane, the use of the reaction of the ketone carbonyl group activity (such as a ketone hydrazine) re-crosslinking reaction in the preparation of the film formation of the aqueous polyurethane, can achieve the purpose of improving the physical and chemical properties of such polymer film . Therefore, the choice of cheap and easily available raw materials, to explore simple synthesis route and the appropriate process parameters, Synthetic able ketone carbonyl introduction of water-based polyurethane molecule, small molecule dual-hydroxy compound, is a very meaningful work. By halohydrocarbon nucleophilic substitution reaction containing ketone carbonyl bis-hydroxyalkyl hydrocarbyl compounds were synthesized, and then a ketone carbonyl group is introduced into the molecular chains of the aqueous polyurethane, the activity of using the reaction of a ketone carbonyl group (ketone hydrazine) was prepared by the deposition occurs when the cross-linking reaction of the aqueous polyurethane, and by comparative experiments, to study the difference in performance before and after the crosslinking aqueous polyurethane. In this experiment, diethanolamine (DEA), 5 - chloro-2 - pentanone (CPE), as raw materials, synthesis of 5 - [bis (β-hydroxyethyl) amino]-2 - pentanone (BHAP), the The compound can be used as the crosslinking agent of the aqueous polyurethane. Explored in order to improve the BHAP the yield experimental temperature, factors such as the acid binding agent, a catalyst and a solvent on the yield and by extraction, vacuum distillation, thin layer chromatography, column chromatography and the product was separated and purified were measured by high-performance liquid chromatography the product mixture the content of BHAP to obtain a higher yield and purity of BHAP. Characterization by infrared spectroscopy and nuclear magnetic resonance spectroscopy (1HNMR, 13CNMR, COSY, HMBC, HMQC) the BHAP structure; BHAP molecular weight was determined by high resolution mass spectrometry and elemental composition. Homemade BHAP as a reforming raw material, 2,4 - toluene diisocyanate (TDI) to link to the aqueous polyurethane molecule as a hard segment and a polyether 210,220, such as a soft segment, dimethylol propionic acid (DMPA diethylene triamine (DETA)) as the center of the ion, as a chain extender, a prepolymer method the synthesized The crosslinked polyurethane water dispersion (CWPU). Crosslinked polyurethane aqueous dispersion viscosity, cross-linked polyurethane film water absorption, suction toluene rate, tensile strength, elongation at break, the measurement of the gel content of crosslinked modified polyurethane film performance. By comparing the experimental study of different carboxyl group content and the amount of crosslinking agent on the performance of the water dispersion of the modified polyurethane, and the discussion and analysis of the difference in performance before and after the crosslinking of waterborne polyurethane. The experimental results show that: the crosslinker the optimum conditions of the synthesis reaction as: N, N-dimethyl formamide (DMF) as solvent, with anhydrous sodium carbonate acid binding agent anhydrous sodium iodide as catalyst, The reaction temperature was 73 ° C, the reaction time is 30H, yield this condition BHAP can reach 90.74% measured by high performance liquid chromatography, the purity of this product was 89.66%. Structural Characterization of the products separated by column chromatography obtained: FT-IR spectra show that the structure of the product having the desired functional group; Nuclear Magnetic Resonance Spectrum (1HNMR, 13CNMR, COSY, HMBC, HMQC) spectrum, The structure of the column chromatography purified material was consistent with the structure of the desired product BHAP; high-resolution mass spectrum shows that the data obtained is consistent with the molecular weight and elemental composition of the desired product BHAP. Comparative studies show that performance of the crosslinkable modified polyurethane film, the NCO / OH molar ratio was 1.28, the carboxyl group content of 1.9% of the cases: BHAP content of 8% of the film when compared with the film not added ADH water absorption decreased by 18.48%, 72.54% suction toluene rate, fracture strength 14.25MPa, a 11.92% increase in the gel mass fraction; NCO / OH molar ratio of 1.28, a carboxyl group content of 2.1% of the cases: BHAP The content of 7% of the film when compared with the film not added ADH, water absorption, a decrease of 64.7%, suction toluene rate decrease of 15.12%, a fracture strength improve 11.81 MPa, the gel mass fraction 4.43% increase.
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