Synthesis, Modification And Characterization Of Hyperbranched Waterborne Polyurethane

Waterborne polyurethane with water as the solvent, with advantages of environmental protection, non-toxic, no pollution, safety, fire prevention, transportation safety, but it also has some shortcomings, such as low solid content, slow drying, poor water resistance and solvent resistance, therefore, in order to improve the performance of waterborne polyurethane, in this case, the modified waterborne polyurethane arises at the historic moment, this not only make substantially improves the performance of the waterborne polyurethane material, and make the application expansion. The method of modified waterborne polyurethane has:crosslinking modification, acry late modified, silicone modified, nano modified and modified epoxy resin etc. With the advantages of chain entanglement between the molecular chains is less, low solution viscosity and good fluidity and easily into the film an so on, hyperbranched polyurethane has not only the advantages mentioned above, but also has the advantages of polyurethane molecules can be designed easily, high tensile strength of the latex film and good resistance. The synthesis methods of hyperbranched polyurethane are mainly three types:functional groups with monomer, functional group different monomer and the expansion of hyperbranched polymer chain method. Hyperbranched polyurethane with extraordinary performance has special application in some aspects, such as in UV curable coatings, solid polymer electrolyte, phase change energy storage application materials, shape memory materials and damping material.In the first chapter, the advantages and shortcomings of waterborne polyurethane are introduced, in order to avoid the defects, there are several kinds of modified methods are particularly successful, such as crosslinking modification, acrylate, silicone modified, nano modified and epoxy resin modified; then introduces the hyperbranched polymer and the definition of the degree of branching, and then introduces the synthesis method of hyperbranched polyurethane, namely, functional group with monomer, functional group different monomer and the expansion of hyperbranched polymer chain method; finally summarized the application of hyperbranched polyurethane in some aspects.In the second chapter, mainly using isophorone diisocyanate (IPDI) and polyether polyol (N220) as raw material, and then add the hydrophilic chain extender dimethylol propionic acid (DMPA) and small molecule chain extender 1,4-butanediol (BDO), synthesis of linear polyurethane prepolymer (LPU), and then add the hyperbranched polyurethane (HBPU-0), after three triethylamine (TEA) and salt, dispersed in water, and finally add ethylenediamine (EDA) as the chain extender in water, with crosslinking structure of hyperbranched waterborne polyurethane (HBPU) was synthesized. The polymer structure is analyzed by infrared spectra and 13C NMR, at the same time, the effects of mole ratio of -NCO and -OH on polymer emulsion particle size, mechanical stability and mechanical properties, thermal stability and absorption of the film were examined. The results showed that:with the increase of the molar ratio of -NCO and -OH, HBPU emulsion particle size has been increased, the tensile strength of the latex film increased, after reaching limit value is reduced, while the elongation at break decreases continuously, bibulous rate is reduced continuously; after joining the HBPU-0, the heat resistance of HBPU adhesive film is higher than that of WPU; when the mole ratio of -NCO and -OH is 8:1, the comprehensive properties of HBPU at best, the emulsion particle size is 75nm, the tensile strength is 9.45 MPa, the elongation at break is 432%, water absorption rate is 5.48% in 24h.In the third chapter, mainly using isophorone diisocyanate (IPDI) and polyether glycol (N220) as raw material, and then add hydrophilic chain extender dimethylol propionic acid (DMPA) and small molecule chain extender 1,4-butanediol (BDO), the synthesis of linear polyurethane prepolymer (LPU), then use hydroxyl ethyl methacrylate (HEMA) on LPU sealing side, join HBPU-0, finally add acrylate monomer emulsified in water, adding ethylenediamine (EDA) as chain extension in water, hyperbranched polyurethane acrylate copolymer emulsion (HBPUA) was synthesized. Change the amount of acrylate, by thermo-gravimetric (TG) analysis and tensile data show that, when m(HBPU):m(PA) =10:6, HBPUA has the best performance, the thermal decomposition temperature reaches 268 ℃, the tensile strength is 8.32MPa. Using infrared spectroscopy characterization of its structure, with phosphotungstic acid to dyeing HBPUA, observed by transmission electron microscopy (TEM), HBPUA shows a core-shell structure.In the fourth chapter, mainly using isophorone diisocyanate (IPDI), polyester polyhydric alcohol and hydroxypropyl silicone oil as raw material, and then add hydrophilic chain extender dimethylol propionic acid (DMPA) and small molecule chain extender 1,4-butanediol (BDO), then add the hyperbranched polyurethane (HBPU-0), the molar ratio of -NCO and -OH is 8:1, finally add ethylenediamine (EDA) in water by chain extension, hydroxypropyl silicone modified hyperbranched waterborne polyurethane (HBPUS) was synthesized. The polymer structure is analyzed by infrared spectra, and at the same time the influence of hydroxypropyl silicone oil after polymer emulsion particle size, the stability and the film of water contact angle, mechanical properties, thermal stability and water absorption rate is discussed. The results showed that:with the increase of the content of hydroxypropyl silicone oil, particle size of emulsion and water contact angle increases, the tensile strength of the latex film continues to decrease, but the elongation at break has been increased, water absorption rate decreased continuously. After joining hydroxypropyl silicone oil, film heat resistance increased, when hydroxypropyl silicone oil content is 10%, the comprehensive performance of glue film at its best, at this point the emulsion particle size is 107 nm, the film of water contact angle is 92, the tensile strength is 14.68MPa, the elongation is 517%, water absorption rate is 6.25% in 48h.