【作者】 罗家和；

【导师】 郭金山；

【作者基本信息】 兰州大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 近年来,传统溶剂型涂料中含有的有害有机挥发物(VOC)会对人身健康和大气产生危害,使人类的生态环境遭到严重破坏,以发达国家为首的许多国家对传统溶剂型涂料的限制越来越严格,从而使水性涂料获得了广泛的研究和应用。因此,用水作为溶剂代替有毒溶剂的水性涂料已经成为涂料发展的主要方向之一尽管如此,目前水性涂料由于应用条件苛刻存在一些困难和问题,如水的高蒸发热和高表面张力,容易产生霉菌等问题都限制了水性涂料的应用。而且,水性涂料涂膜的耐化学性、耐热性和力学性能等方面还不能与传统溶剂型的涂膜性能相媲美。尽管如此,水性涂料逐渐代替溶剂型涂料是势在必行。水性涂料和紫外光固化涂料被认为是最有希望实现环境友好涂料目标的技术,而如果将水性技术和紫外光固化技术有机地结合起来,开发新型水性紫外光固化涂料,将会在降低对环境的危害方面取得突飞猛进的进展。水性光固化涂料的优点突出,然而其浸润性差、易引起涂布不均,涂膜耐热性、耐冲击性、耐开裂性和耐湿热性较差等缺点,在很大程度上限制了它在某些高技术领域的应用,因此需要通过改性改善水性光固化涂料的性能。多年来硅化合物一直用来改性有机树脂,以此提高性能。因此,一个改善水性光固化涂料性能的有效途径就是在高聚物中引入硅化合物。通过硅改性的水性光固化涂料将会具有更好的浸润性、耐热性和力学性能。因此本论文研究的内容主要是通过适当的方法将纳米二氧化硅／有机硅引入到水性光固化树脂中,然后制备出含有纳米二氧化硅／有机硅改性的具有较好涂膜性能的水性光固化涂料。(1)在水性光固化聚氨酯乳液合成过程中引入纳米二氧化硅水溶胶,利用纳米二氧化硅与聚氨酯分子的氢键作用制备聚氨酯纳米复合乳液,详细研究了纳米二氧化硅对涂膜耐热性、耐水性和力学性能的影响。结果表明纳米二氧化硅的存在提高了膜的耐水性,当纳米二氧化硅质量分数达到6%时,聚合物膜的吸水率稳定在10.28%,显示出良好的拒水性能；纳米二氧化硅能有效地实的实现对膜的硬度、抗冲击力、附着力和柔韧性等力学性能的提升；热重分析证明纳米二氧化硅的引入改善了固化涂膜的热稳定性。本方法制备的纳米二氧化硅复合涂层在耐磨木器、耐高刮伤、塑胶等表面涂层领域有很好的应用前景。(2)将KH550引入聚氨酯大分子链段末端,得到一系列KH550改性水性光固化聚氨酯乳液,用FT-IR对产物结构进行了表征,说明有机硅烷已被引入到聚氨酯骨架中。研究结果结果表明硅氧链段的引入提高了膜的耐水性；涂膜性能测试表明涂膜附着力、柔韧性等力学性能均有所提高；热重分析证明有机硅的引入改善了固化涂膜的热稳定性。当KH550质量分数大于3.433%时,膜的力学性能没有明显提升,聚合物膜可以在达到良好表面拒水性的同时保持较好的附着力、柔韧性。由实验得出的最佳KH550添加量和反应物配比可以为水性光固化聚氨酯的改性研究和实际生产应用提供参考。(3)将KH560引入水性环氧丙烯酸大分子链段末端,得到一系列零VOC的KH560改性水性光固化环氧丙烯酸水分散体,对产物结构进行表征,并测试了所得聚合物膜的耐水性、力学性能和热稳定性能。涂膜性能测试表明涂膜耐水性、附着力、柔韧性等均随着有机硅的引入有所提高；热重分析证明有机硅的引入改善了固化涂膜的热稳定性。本实验为水性光固化有机硅树脂改性环氧丙烯酸树脂性能的深入研究提供了方法指导。更多还原

【Abstract】 Recently, waterborne coatings have gained increasing attention due to strict environmental regulations on the emission of volatile organic compounds (VOC) from solvent-borne coatings. VOC in paints and coatings is of particular interest due to their adverse effects on the environment. Using water instead of hazardous solvent is the rational behind waterborne coatings which aims for total reduction of toxicity without compromising environmental concerns. At present, however, waterborne coatings are considered unsatisfactory as the application conditions are often critical; they are difficult to apply because of their rheological behavior and poor wetting, temperature and humidity have to be strictly controlled for correct curing conditions, etc. Moreover, once applied, their performances are usually inferior to the traditional coatings.The use of waterborne coatings in combination with the UV-curing technique is also very attractive since the UV-curing process offers many advantages too.The advantages of UV-curable waterborne coatings are obvious, however, their poor wetting, thermal and mechanical properties have limited their applications, so they need some modifications. For many years silicon intermediates have been used to modify organic resins to increase their properties. Therefore, one possibility to get higher performance materials is incorporating silicon in the polymer network. UV-curable waterborne coatings modified with silicon can be used to formulate coatings having high hardness with excellent flexibility, thermal stability and better wetting.Here, we synthesized a series of nano SiO2/functionalized siloxane modified UV-curable waterborne coatings by incorporating the nano SiO2/functionalized siloxane into the organic resins. The films of the nano SiO2/functionalized siloxane modified UV-curable waterborne coatings show excellent properties such as surface hardness, water resistance, heat resistance, flexibility and mechanical properties owing to the excellent bond strength of the Si-O-Si. In this study, we synthesized a series of nano SiO2 modified UV-curable waterborne polyurethane emulsions (SiO2-PUs) by the effect of hydrogen bonds between nano SiO2 and polyurethane chains. A detailed study of the effect of nano SiO2 on the heat stability, water resistance and mechanical properties of the films was carried on. It was found that incorporating of nano SiO2 can improve the water resistance of the films. When the nano SiO2 content was 6%, the water absorption of the films was stable at 10.28%. It was also found that incorporating of nano SiO2 can improve the thermal stability and many mechanical properties of the films. The coating thus formed can serve as a good scratch, abrasion, water resistant and heat resistant coating and can find applications in various practical situations.Here, we synthesized a series of KH550 modified UV-curable waterborne polyurethane emulsions (Si-PUs) by incorporating the KH550 into the end of the PUs chains. The Si-PUs was characterized by using FTIR spectroscopy and the results showed that the KH550 had been successfully introduced into the polyurethane chains. It was found that incorporating of KH550 can improve the thermal stability, water resistance, and many mechanical properties of the films. It can be seen that when the KH550 content was greater than 3.433%, the mechanical properties of the films did not significantly improve while maintaining good water resistance. The best content of KH550 and the ratio of reactants for the modification obtained by the experiment can provide information to the research of modifying UV-curable waterborne polyurethane and practical application.In this study, we synthesized a series of 0 VOC KH560 modified UV-curable waterborne epoxy acrylic dispersions (Si-EAs) by incorporating the Tetrahydrophthalic anhydride and the KH560 into the end of the epoxy acrylate chains. The Si-EAs was characterized by using FTIR spectroscopy and the results showed that the KH560 had been successfully introduced into the epoxy acrylate chains. It was found that incorporating of KH560 can improve the thermal stability, water resistance, and many mechanical properties of the films. The experiment can provide methodological guidance to the research of modifying UV-curable waterborne epoxy acrylic resin.更多还原