【作者】 辛华；

【导师】 沈一丁；

【作者基本信息】 陕西科技大学 ， 材料物理与化学， 2012， 博士

【摘要】 目前关于阳离子型水性聚氨酯的研究报道相对较少，但因其骨架上带有阳离子基团，使其具有一些独特的性能，在造纸、皮革、纺织、涂料和胶粘剂等领域有着较好的应用。传统的水性聚氨酯由于分子结构的限制使其涂膜的力学性能、耐水性、耐溶剂性等相关性能不足，常引入疏水性链段或交联结构对其改性。疏水性的氟链段可通过含氟二元异氰酸酯、含氟聚醚二元醇、含氟聚酯二元醇及含氟扩链剂等方法引入，此均是逐步聚合机理；本研究采用全氟烷基丙烯酸酯通过自由基聚合机理引入聚氨酯体系。通过物理复合及化学交联两种方法制得全氟烷基丙烯酸酯改性阳离子聚氨酯复合乳液。研究了复合乳液及其乳胶膜的结构与性能。为全氟烷基丙烯酸酯改性阳离子聚氨酯的制备、乳液性能、成膜性能和使用性能提供理论基础。因全氟烷基丙烯酸酯具有全取代的氟碳烷基，具有更低表面自由能，且全氟烷基位于大分子侧链，具有更好的表面迁移性，有助于提高其表面性能。首先以脂环族二元异氰酸酯异佛尔酮二异氰酸酯(IPDI)为硬段，以聚醚二元醇聚四氢呋喃醚(PTMG)为软段，以N-甲基二乙醇胺(MDEA)为亲水性扩链剂，以多功能团的小分子醇三羟甲基丙烷(TMP)为内交联剂，合成一种自乳化自交联的水性阳离子聚氨酯(CPU)乳液，CPU大分子上既有亲水基团又有亲油基团，可视为高分子表面活性剂。重点讨论了主要合成因素如软段种类及分子量、R值、MDEA用量及TMP用量等对CPU乳液及乳胶膜性能的影响。接着以N-甲基二乙醇胺(MDEA)为阳离子亲水性扩链剂，三羟甲基丙烷(TMP)为内交联剂，先将全氟烷基丙烯酸酯(FA)与其它乙烯基单体（St和BA）的混合液作为聚氨酯制备的稀释剂，经相转化法合成了阳离子水性聚氨酯(PU)乳液；再以其为种子乳液，采用水溶性偶氮引发溶胀在其中的乙烯基单体（FA、St和BA）进行自由基共聚合，制得稳定的物理复合改性的全氟烷基丙烯酸酯/阳离子水性聚氨酯(PUFA)复合乳液。重点讨论了FA单体用量对复合乳液及其乳胶膜性能的影响规律。在上面引入全氟烷基丙烯酸酯强疏水性组分改性阳离子聚氨酯基础之上，进一步通过高分子设计使得复合体系形成化学交联结构从而进一步提高其性能。通过带有羟基的乙烯基单体丙烯酸羟乙酯(HEA)对阳离子聚氨酯预聚体两端封端，其作为双烯类大单体可与全氟烷基丙烯酸酯自由基共聚形成交联体系，得到明显核壳结构的改性复合乳液(FAPU)。重点讨论了合成因素对复合乳液稳定性的影响，以及软段分子量、FA单体用量和MDEA单体用量等因素对复合乳液及其稳定性的影响，最后初步研究了FAPU乳液在纸张表面上施胶性能。结果表明物理复合法及化学交联法所得全氟烷基丙烯酸酯改性阳离子聚氨酯复合乳胶膜力学性能、耐水性及热稳定性相比改性前的聚氨酯明显提高。且因为全氟烷基结构的引入，所得复合乳液具有优良的表面性能，其表面自由能在20mJ/ m2，这个数值小于水(72.8mJ/m2)和一般油类(25～35mJ/ m2)的表面自由能，这也正是含氟聚合物具备防水防油性的理论基础。经更高温度热处理后，复合乳胶膜的表面自由能会进一步下降。通过原子力显微镜(AFM)测试可以看出，膜表面整体平整、微观粗糙。X射线光电子能谱(XPS)分析表明，复合乳胶膜表面氟元素的实际含量远高于理论值，全氟烷基链段明显地向表面富集。应用实验表明较佳的纸张表面处理工艺是：施胶液固含量3‰，后处理温度120℃，后处理时间3min。复合乳液处理过纸张，水和液体石蜡在其上接触角分别可达132 o和108 o，且液滴在纸张表面停留5min以内接触角基本不变。这表明经复合乳液处理过的纸张具备良好的防水防油性。更多还原

【Abstract】 Although anionic PU emulsions are often encountered in the literature, therehave been not many reports about the preparation and the properties of thecationic PU, which show very high adhesion to various ionic substrates,especially anionic substrates such as paper, leather, textile, coatings and adhesive.Some inferior properties of traditional waterborne polyurethanes (WPU) such aslow mechanical strength, water and solvent resistance restrict utility for highperformance applications of WPU. It is important to modify the WPU byintroducing hydrophobic chain segments or cross linked structure into WPU.Fluorocarbon chains can be incorporated into polyurethane via fluoro-containingdiisocyanates, polyether glycols, polyester glycols and chain extender, always bystep polymerization. Perfluorinated acrylate was chose to preparepolyurethane-fluorinated acrylic hybrid emulsions by radical copolymerization inour study system. As an alternative to the step polymerization, free radicalcopolymerization has emerged as an attractive and simple method for producingfluorinated polyurethane. First, preparation and properties of cationic waterbonepolyurethane were studied. Then the cationic polyurethane-perfluorinatedacrylate hybrid emulsions were prepared by physical compound method andchemical crosslink method, respectively. Structures and properties of hybridemulsions latexes and their films were studied, which could provide fundamentalinformation for film-forming performance and operational performance ofcationic polyurethane-perfluorinated acrylate hybrid emulsions.A serial of selfcrosslinked and selfemulsifying polyether cationicpolyurethane (CPU) emulsions were prepared by usingpolytetrahydrofuran glycol (PTMG1000) as soft segment, N-methyl diethanol amine (MDEA) as cationic chain-extender and trimethylolpropane (TMP) asinner crosslinker.The CPU emulsions were modified with the hydrophobic perfluorinatedacrylate (FA) by the physical compound method. In the cationic polyurethanesprepolymer preparation step, the vinyl monomer mixture was added in order toreduce the high viscosity of reactive system instead of traditional organic solvent.There was no small molecule emulsifier used in the perfluorinated acrylateradical copolymerization step which relied on the cationic group of CPU tosupply hybrid emulsion stability and belong to emulsifier-free polymerization.The cationic polyurethane prepolymer were prepared with MDEA as hydrophilicchain extender, TMP as innercrosslinker and the perfluorinated acrylate and theother vinyl monomer as diluter instead of traditional solvent. After theneutralization and dispersion of the prepolymer, the PU emulsion swollen byvinyl monomer obtained, which acted as the seed emulsion and the vinylmonomer swollen in PU latexes took place radical copolymerization in it andthen the cationic polyurethane-perfluorinated acrylate hybrid emulsions (PUFA)were obtained.On the basis of CPU modified with perfluorinated acrylate, the properties ofhybrid polymer were tried to been raised by crosslink structure. The aqueouscationic polyurethane dispersion was prepared by using tertiary amine group tomake the polyurethane dispersible and then nanograde core-shell and crosslinkedstructure FAPU hybrid emulsions containing perfluoroalkyl side-chains wereobtained from double bond-end capped polyurethane macromonomers withperfluoroalkyl acrylate by radical copolymerization.The results showed the mechanical strength, water resistance and the heatstability of the hybrid films enhanced. The hybrid films showed excellent surfaceproperties due to the introducing of the perfluorinated group. The surface freeenergy of the hybrid films were about 20mJ/ m2，which was lower the surfacefree energy of water (72.8mJ/m2)and common oil (25-35mJ/ m2)，so the hybridfilms had the water and oil repellent properties. The study results also showedthat the surface free energy could be reduced under the higher heat treattemperature. Through surface morphology observation of atomic forcemicroscope (AFM), it can be seen that the surface morphology of smooth overall but micro-rough was formed. X-ray photoelectron spectroscope (XPS) analysisshowed that the practical content of fluorine on the perfluorinated polymermembrane surface was much higher than the theoretical value which indicatedthat perfluoroalkyl chains had significant enrichment to the surface. Apreliminary study of the application performance of FAPU on paper surfacesizing proceeded at last. The better technology was: the sizing emulsion solid ofFAPU was 3‰, the annealing temperature was 120℃and the annealing timewas 3 minutes. The water and liquid paraffin contact angles of the paper treatedby the FAPU hybrid emulsion with 30% FA content were 132 o and 108 o,respectively. The contact angles almost changed nothing during 5 minutes. Allthese showed that the papers treated with the hybrid emulsion possessed goodwater and oil repellent properties.更多还原