Synthesis, Characterization And Application Of Waterborne Polyurethane Hydrophilic Chain Extender

In this paper, sulfonic acid and carboxylic acid types of hydrophilic chain extenders were synthesizd, which were applied to the preparation of waterborne polyurethane and hyperbranched waterborne polyurethane, and then the films were made a series of performance testing. The main contents and results were as follows:A sulfonic acid type of hydrophilic monomer N,N-(2-hydroxyethyl)-2-amino-propane was synthesized by substitution and sulfonation reaction. The synthesis conditions were optimized through single factor experiments. And the products were characterized by FT-IR, 1H-NMR, organic elemental analysis, X-ray diffraction and thermal analysis. FT-IR, 1H-NMR and elemental analysis showed that the synthesized product is expected target product; X-ray diffraction measurement results showed that the product was a crystalline compound; simultaneous thermal analysis showed that the decomposition temperature of the sulfonic acid type monomer was 278.1 which ha℃ d a excellent thermal stability.Succinic anhydride and diethanolamine as the main raw materials react with methanol as solvent to produce the carboxylic acid waterborne polyurethane chain extender DMCA. Under the optimal conditions the conversion rate had reached 86.18%. The DMCA was characterized by modern equipments. FT-IR, 1H-NMR and elemental analysisn showed that N,N-(2-hydroxyethyl)-2-aminoacid(DMCA) was the desired product; XRD showed that the DMCA was non-crystalline compound; TGA studied the thermal stability of DMCA which thermal decomposition temperature was 263.7℃.The hydroxyl-terminated hyperbranched polymer(HPAE) was prepared, and the use of carboxylic acid type monomers of dihydroxy methyl propionic acid(DMPA), dihydroxy methyl butyric acid(DMBA) and homemade carboxylic acid monomer DMCA as hydrophilic chain extenders, three kinds of carboxylic acid hyperbranched waterborne polyurethanes were synthesized respectively. The three kinds of HWPU were characterized by modern equipments. The conclusions were as follows:The FT-IR spectrograms proved that three kinds of hyperbranched waterborne polyurethanes were similar in structure, and were all connected to –COOH and had hydrophilicity. Crystallinity: DMBA-HWPU<DMPA-HWPU< DMCA-HWPU. DMCA-HWPU was better than the other two in the crystalline properties. SEM showed that three kinds of hyperbranched waterborne polyurethanes are all formated a dense of network structure. The surface roughness of DMCA-HWPU was better. Three types of polyurethane emulsion were milky and had blue light, no precipitation. The stability of emulsions: DMBA-HWPU< DMCA-HWPU<DMPA-HWPU. It can be seen from the simultaneous thermal analysis curves, DMCA-HWPU in thermal performance was fairly with DMPA-HWPU and DMBA-HWPU. The physical and mechanical properties: DMCA-HWPU>DMPA-HWPU>DMBA-HWPU. The water absorption and the solvent resistance of DMCA-HWPU were fairly with the polyurethanes which synthesized with commercially available hydrophilic monomers of DMPA and DMBA.