N-甲基二乙醇胺用量对水性阳-非离子聚氨酯溶液性能的影响

Effects of N-Methyldiethanolamine Concentration on Solution Properties of Waterborne Cationic-Nonionic Polyurethane Surfactants

通过预聚体法合成了水性阳-非离子聚氨酯表面活性剂(CPUS),利用红外光谱和核磁共振谱对聚合物的结构和组成进行了表征.并通过动态光散射(DLS)、透射电镜(TEM)、表面张力仪、稳态流变分析及荧光光谱法等系统研究了阳离子亲水扩链剂N-甲基二乙醇胺(MDEA)用量对CPUS表面张力、临界胶束浓度、流变性、胶束的尺寸、微极性和聚集行为的影响.TEM表明,CPUS胶束呈球形核壳结构.随着MDEA含量的增加,CPUS水溶液表面张力和临界胶束浓度(CMC)先减小后增大,其最低值分别为39.54 m N/m和1.99 g/L,胶束的平均粒径和分布系数逐渐减小.当浓度低于CMC时,光散射强度较低且变化缓慢,当浓度高于CMC时,光散射强度呈现逐渐增长趋势,胶束聚集数逐渐增加.随着MDEA含量的增加,乳液黏度增加,胶束间的相互作用增强,假塑行为增强.荧光光谱法表明随CPUS浓度增加,I1/I3值从1.8降低到1.3,I338/I334值从0.5升高到1.7,表明疏水基团聚集形成疏水微区,芘分子从水相极性环境转移到胶束疏水内核.随着MDEA含量的增加,胶束微极性和形成难度先减小后增加.

A series of waterborne cationic-nonionic polyurethanes surfactants （CPUS） was prepared through prepolymerization method and their structures were investigated by FTIR and ^1H-NMR. The effects of N- methyldiethanolamine （MDEA） concentration on the surface tension, critical micelle concentration, rheology property, micelle size, micropolarity and aggregation behaviors of CPUS were studied by DLS, surface tension analysis, steady state theological analysis and fluorescence analysis. TEM results showed that CPUS micelles displayed as core-shell spheres. It was also found that average micelle particle size and polydispersity index of CPUS solutions decreased with increasing MDEA concentration. While the surface tension and critical micelle concentration （CMC） decreased first and then increased, the lowest of which were 1.99 g/L and 39.54 mN/ m. When the CPUS concentration was lower than CMC,the light scattering intensity was very low and changed slowly with CPUS concentration. However, the light scattering intensity displayed a gradually increasing tendency when the CPUS concentration was greater than CMC. Meanwhile, the aggregation number of CPUS micelles increased greatly. The viscosity of CPUS solution increased with increasing MDEA concentration, as well as the interactions among micelles increased,while the pseudoplastic behavior was enhanced. In addition, fluorescence spectrometry showed that I1/I3values decreased from 1.8 to 1.3 and 1338/1334 increased from 0.5 to 1.7, suggesting that the hydrophobic groups tended to aggregate and form hydrophobic microdomains, and pyrene molecules transfered from the aqueous polar phase to micellar interphase. Furthermore, the micelle micropolarity and the difficulty with micelle formation decreased first and then increased as increasing MDEA concentration.