以二聚脂肪酸聚酯二元醇为软段合成水性聚氨酯-脲(英文)

Waterborne polyurethane-urea prepared with dimer fatty acid based polyester polyol as soft segment

以C36二聚脂肪酸聚酯二元醇为软段,合成了一系列贮存稳定性优异的聚氨酯-脲(PUU)水分散液。与由己二酸聚酯二元醇制备的PUU水分散液相比,这类PUU水分散液的粒径减小,成膜后的耐水性和力学性能明显提高,其中硬段质量分数为35%的水分散液(DPU 35)成膜后的吸水率最低,仅为1. 3%。进一步在DPU 35中添加少量的含氟聚丙烯酸酯乳液,发现水在这种改性PUU膜表面的接触角上升到96°,表现出良好的疏水性,材料的力学性能也更高。

The physical properties of waterborne polyurethane and polyurethane-urea-acrylate are significantly affected by the compositions of soft segments [1] . Erwin et al [2] reported that C 36 -dimer fatty acid(DFA) based polyester polyol could be used to prepare the waterborne polyurethane and its mechanical properties were measured. In this article, a series of polyurethane-urea(PUU) aqueous dispersions were prepared with C 36 -DFA based polyester polyol or adipate polyester polyol as soft segment, as well as isophorone diisocyanate and dimethylol propionic acid. These PUU aqueous dispersions were called DPU or APU. For enhancing the hydrophobic performance of the waterborne PUU further,mass fraction of the fluorinated polyacrylate emulsion [3] 1.0% and 3.0% were added into DPU-35 to prepare the modified aqueous dispersions, MPU-1 and MPU-3 respectively.Table 1 shows that the particle size of the DPU systems increases with increasing the mass fraction of hard segment, but it is much smaller than the comparable specimen(APU-35). The particle size of fluorinated polyacrylate modified PUU aqueous dispersions only a bit increases as compared with the unmodified one. Table 2 shows that the water resistance and the mechanical properties of the DPU films enhance appreciably as compared with those of APU-35 film, and the DPU-35 film shows the lowest water absorption over all PUU films prepared. Compared with that of DPU-35 film, the surface hydrophobicity of the MPU film enhances further, as the water contact angle on the surface of MPU-3 film rises up to 96°. Although the water absorption of MPU film is a little higher than that of DPU-35 film due to the existence of the emulsifying agent in the fluorinated polyacrylate emulsion [3] ,the mechanical properties of MPU film are higher than those of DPU-35 film.