具有明确硬段结构的水性聚氨酯脲的研究

通过逐步反应由4,4′-二苯基甲烷二异氰酸酯、2,2-二羟甲基丙酸和1,4-丁二醇,合成了结构明确的硬段模型化合物.通过13C NMR对其序列结构进行了表征,并通过FTIR、DSC和WAXD对其形态结构进行了研究.进一步制备了具有这类规整结构硬段的水性聚氨酯脲,初步考察了水分散液及其成膜后的性能.实验结果表明,这类聚氨酯脲水分散液的粒径小于110nm,在室温下贮存期大于一年,成膜后具有优异的耐水性能以及表面疏水性能.

STUDIES OF A WELL-DEFINED MODEL HARD SEGMENT AND WATERBORNE POLYURETHANEUREA

A well-defined model hard segment was synthesized with 4,4′-diphenylmethane diisocyanate,dimethylolpropionic acid and 1,4-butanediol by means of fractional steps.The sequence distribution of the model hard segment was measured by 13C-NMR and its structure and morphology were characterized by FT-IR,DSC and WAXD.A series of polyester based polyurethaneurea (PUU) aqueous dispersions with this well-defined hard segment were prepared.The physical properties of PUU aqueous dispersions and their films were measured. The experimental results showed that the particle size of the aqueous dispersions decreased with increasing the hard segment content from 110 nm to 72 nm,and they were very stable at ambient temperature (more than one year).Furthermore,the films prepared with such PUU aqueous dispersions exhibited the excellent water resistance,i.e.low equilibrium water absorbing capacity (at around 5 wt%) and high contact angle of water on the surface (more than 100°).