室温自交联有机氟接枝改性水性聚氨酯的可控合成与性能研究

Due to improvement of water-resistance and solvent-resistance properties, cross-linking and organic fluorine modifications on the waterborne polyurethanes have been attracted considerable attention in recent years. In this project, room temperature self cross-linkable waterborne polyurethane modified with organic fluorine will be synthesized via RAFT emulsion polymerization. Vinyl-teminated polyurethane macro-monomers will be synthesized by the reaction of NCO-terminated polyurethane prepolymers and fluorine-containing diol and ketone carbonyl-containing diol. The main work will be to characterize the diols and vinyl-terminated polyurethane macro-monomers. And the difference of RAFT emulsion polylmerization of vinyl-terminated polyurethane macro-monomers and other monomers will be focused studied. In addition, the synthesis conditions of vinyl-terminated polyurethane and the effects of cross-linking and fluorine content on the properties of emulsions and films will be discussed in detail. And on the other hand, the relationship between micro-structure and the properties will be researched to provide theoretical basis for new-type waterborne polyurethane materials.

设计、合成室温自交联有机氟接枝改性水性聚氨酯，提高其耐水性和耐溶剂性，是近来一个重点关注的研究课题。本项目提出来以活性可控聚合的方法，可控制备室温自交联有机氟接枝改性水性聚氨酯。首先合成结构清晰的含氟二元醇和含酮羰基二元醇，通过丙烯酸羟乙酯封端法制备乙烯基封端侧链含酮羰基和有机氟接枝改性水性聚氨酯大分子单体，采用RAFT乳液聚合的方法，可控合成室温自交联有机氟接枝改性水性聚氨酯共聚物材料。着重研究含氟二元醇和含酮羰基二元醇及其乙烯基封端聚氨酯大分子单体的合成工艺和结构表征，重点考察乙烯基封端聚氨酯大分子单体的聚合规律，详细研究交联和氟含量对水性聚氨酯乳液和胶膜性能的影响，提出微相分离结构与水性聚氨酯性能的构效关系，为开发新型的室温自交联有机氟接枝改性水性聚氨酯提供理论依据。

水性聚氨酯以水为主要的分散介质，不含或含有少量溶剂，绿色环保，但在制备水性聚氨酯的过程中，亲水基团的引入以及较低的分子量，导致水性聚氨酯涂膜的耐水性、耐溶剂性及耐热性不佳，从而限制了其使用范围。本研究以有机氟改性和交联改性为基础，通过迈克尔加成反应合成含氟二元醇和酮羰基二元醇，通过酮肼交联实现了室温自交联有机氟接枝改性水性聚氨酯乳液的制备。首先以二乙醇胺和甲基丙烯酸三氟乙酯为原料，通过迈克尔加成反应，合成含氟二元醇trifluoroethyl-2-methylpropanoate-β-dihydroxyethylamine，制备了有机氟接枝改性水性聚氨酯。实验发现，合成的含氟二元醇，合成条件温和，收率高，柱层析法纯度大于99%，有机氟的引入，能够显著提高聚氨酯胶膜的耐水性、耐溶剂性等性能，同时胶膜具有优良的断裂伸长率（均大于1000%）；其次，以二乙醇胺和双丙酮丙烯酰胺为原料，合成了含酮羰基二元醇N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamine，制备了室温自交联水性聚氨酯。含酮羰基二元醇的引入，在挥发性碱性条件下（三乙胺，pH值~8），在室温乳液挥发成膜的过程中，实现了酮肼交联反应，能够提高胶膜的机械强度和耐水性、耐溶剂性能。最后以合成的含氟二元醇和含酮羰基二元醇为原料，通过顺序加料的方式合成了链段含有机氟和酮羰基基团的乙烯基封端聚氨酯大分子大体，以合成的小分子RAFT试剂2-(dodecylthiocarbonothioylthio) propanoic acid为活性调控剂，通过活性/可控乳液聚合，实现了室温自交联有机氟接枝丙烯酸酯改性水性聚氨酯乳液的可控合成，乳液稳定，性能优异。