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通过改变合成单体种类、配比及合成方法,合成了不同结构的聚氨酯预聚体并乳化为水性聚氨酯乳液(PUD),对乳液的粒径大小,固含量,耐酸、耐盐稳定性,电势以及羧基在乳液粒子的表面分布进行分析。结果表明:羧基在预聚体分子中的位置对PUD的分散性、稳定性及乳液粒子的溶胀有显著的影响。羧基未与长疏水链连接在一起所产生的分散效果最差、乳液不稳定;羧基位于两低聚物二元醇分子之间产生的分散效果稍好,但使乳液粒子产生较大的溶胀;而羧基靠近预聚体分子一端且与长疏水链连接在一起则产生良好乳化效果。虽然羧基均处于PUD乳液粒子表面,但乳液耐酸、耐电解质性能有明显差异,且与乳液粒子的电势大小无必然联系。
Polyurethane prepolymer with different structures was synthesized and emulsified into water-based polyurethane emulsion (PUD) by changing the types, proportioning and synthesis methods of synthetic monomers. The effects of particle size, solid content, acid resistance, salt stability, And the distribution of carboxyl groups on the surface of emulsion particles. The results show that the position of the carboxyl groups in the prepolymer molecules has a significant effect on the dispersibility and stability of the PUD and the swelling of the emulsion particles. The dispersion effect of the carboxyl group not linked to the long hydrophobic chain is the worst, the emulsion is unstable; the dispersion effect of the carboxyl group between the two oligomer diol molecules is slightly better, but the emulsion particles are greatly swollen; The carboxyl group near one end of the prepolymer molecule and long hydrophobic chains are linked together to produce a good emulsifying effect. Although the carboxyl groups are all on the surface of PUD emulsion particles, the properties of acid-resistant and electrolyte-resistant emulsions are obviously different, which are not necessarily related to the potential of emulsion particles.