摘要： 以不同烷氧基取代的Percec型苯甲醇树形分子作为封端剂,制备3种具有相同亲水链段但末端疏水尾链数不同的聚氨酯缔合增稠剂(HEURs):HEUR-1C10(单尾)、HEUR-2C10(双尾)和HEUR-3C10(三尾)。通过红外光谱和凝胶渗透色谱对HEURs的结构和相对分子质量进行了表征,并采用应力控制型流变仪研究了不同HEUR添加量的纯丙乳液的稳态及动态剪切行为。结果发现:二取代和三取代树形分子封端的HEUR-2C10和HEUR-3C10的增稠效果明显好于普通单疏水尾链封端的HEUR-1C10。这表明在亲水链段相同时,短而多的疏水链有利于增加有效网链密度,使得相邻胶束和乳液粒子之间产生更多的桥连,形成更强的疏水网络结构。本研究为新型高效聚氨酯增稠剂的制备与应用提供了有益的借鉴。

关键词: 树形分子, 疏水改性乙氧基化聚氨酯, 增稠剂, 乳液, 流变学

Abstract: Three novel dendron hydrophobically modified ethoxylated urethanes (HEURs) end-functionalized by Percec=type alkyl substituted benzyl alcohol dendrons with identical hy-drophilic portion but different terminal hydrophobic tail number have benn synthesized: HEUR-IC10 for single-tail, HEUR-2C10 for two-tail and HEUR-3C10 for three-tail, respectively. The structure and molecular weight of these HEURs are characterize by FT-IR and GPC. A comparative study of their rheological properties in latex is performed by steady state and oscillatory shear measurements in detail. The results show that the HEUR-2C10 and HEUR-3C10 have stronger thickening performance than HEUR-1C10. In addition, the end-cappers with shorter and more tails help HEURs to form a stronger physical network with the larger number density of active micellar junctions and get a higher thickening performance. This work offers a new approach to preparation of highly efficient HEURs thickeners.

Key words: dendron, hydrophobically modified ethoxylated urethane, thickener, latex, rheology