水工混凝土表面氟碳纳米复合涂层的制备及防护耐久性研究
发布时间：2018-07-17 06:03
【摘要】：随着水资源的持续开发,近年来纳入规划的172项重大水利工程主要集中于中西部地区,并逐渐往水资源丰富的西部高海拔、寒冷地区转移。该地区水工建筑物通常面临更为复杂和苛刻的服役环境(如海拔高、温差大、紫外线辐照强、冻融循环频繁等),其中冻融和紫外辐照是造成水工混凝土结构损伤劣化的最具代表性的影响因素。因此,开发出防水、耐候性佳且高效持久的水工混凝土表面防护涂层,使混凝土结构免受或减缓环境因子侵蚀作用,将有助于提高西部高海拔地区水工建筑物耐久性和安全性,提升我国水利工程建设质量和运行维护水平。氟碳涂层由于具有优异的低表面能特性、耐介质腐蚀性能和耐候性等优点,已成为表面防护的有效手段之一。然而,此类涂层用于水工混凝土表面防护时,尚面临粘结性能不足、表界面耐久性有限等技术难题,限制了其大规模使用。本文通过在低表面能氟碳涂层中引入纳米材料,制备兼具优异表面疏水性能和粘接性能的氟碳纳米复合涂层。通过分析涂层组成和涂覆工艺对表界面性能的影响,研制了由“氟碳/纳米SiO2底涂+氟硅烷面涂”组成的氟碳纳米复合涂层双涂层体系,即首先将自制的室温固化型氟碳/纳米二氧化硅复合涂层涂覆于水泥砂浆表面,待其表干后涂覆全氟辛基三乙氧基硅烷。通过紫外老化试验、冻融循环试验、冻融-紫外交替循环试验以及耐水性试验,并采用傅里叶变换红外光谱、扫描电镜、接触角测试、拉拔试验等测试手段研究了涂层材料本身和涂层/砂浆体系的耐久性。结果显示,纳米SiO2的引入能够改善涂层/砂浆试件的耐紫外老化性能、抗冻融循环性能和抗冻融-紫外交替循环性能;当纳米SiO2粒子含量为10%时,涂层/砂浆表面耐久性最佳,界面粘接耐久性能保持良好。结合傅里叶变换红外光谱、扫描电镜等微观表征结果以及耐久性研究结果,初步分析了涂层本体和涂层/砂浆体系的老化规律和机理。涂层本体老化的主因是光老化过程中,氟碳中的酯键易发生断裂,导致耐紫外老化性能下降;涂层/砂浆界面老化过程中,长时间的紫外辐照使得涂层容易发生交联反应,致使涂层分子与砂浆基体之间的结合更加紧密,但紫外老化达到一定时间后,持续的紫外高温照射使得涂层与砂浆界面的相容性变差,导致涂层与砂浆之间的结合强度有所下降。
[Abstract]:With the sustainable development of water resources, 172 major water conservancy projects which have been included in the planning in recent years are mainly concentrated in the central and western regions, and gradually transferred to the high altitude and cold regions of the western regions with abundant water resources. Hydraulic structures in the area generally face more complex and demanding service environments (such as high altitude, large temperature differences, strong ultraviolet radiation, Among them, freeze-thaw and ultraviolet irradiation are the most representative factors that cause damage and deterioration of hydraulic concrete structure. Therefore, the development of waterproof, weatherproof and efficient and durable surface protection coating of hydraulic concrete, which can protect concrete structure from or slow down the erosion of environmental factors, will help to improve the durability and safety of hydraulic structures at high altitude in western China. We will improve the quality of water conservancy construction and the level of operation and maintenance in China. Fluorocarbon coating has become one of the effective methods of surface protection because of its excellent low surface energy properties, corrosion resistance and weathering resistance. However, when this kind of coating is used for surface protection of hydraulic concrete, it still faces some technical problems, such as insufficient bond property and limited durability of surface interface, which limits its large-scale application. In this paper, fluorocarbon nanocomposite coatings with excellent surface hydrophobic and adhesive properties were prepared by introducing nano-materials into low surface energy fluorocarbon coatings. By analyzing the influence of coating composition and coating process on the surface interface properties, a fluorocarbon nanocomposite coating double coating system composed of fluorocarbon / nano Sio 2 coated fluorosilane surface was developed. The self-made room temperature curing fluorocarbon / nano-silica composite coating was first coated on the surface of cement mortar, and then perfluorooctyl triethoxy silane was coated on the surface of cement mortar. Through ultraviolet aging test, freeze-thaw cycle test, freeze-thawing-ultraviolet alternate cycle test and water resistance test, Fourier transform infrared spectroscopy, scanning electron microscope, contact angle test, The durability of coating material and coating / mortar system was studied by drawing test. The results show that the introduction of nano-SiO _ 2 can improve the UV aging resistance, freeze-thaw resistance and anti-freeze-thaw alternate cycle performance of the coating / mortar, and the surface durability of the coating / mortar is the best when the content of nano-SiO _ 2 particles is 10. Interfacial adhesion durability is maintained. The aging law and mechanism of coating body and coating / mortar system were preliminarily analyzed by means of Fourier transform infrared spectroscopy, scanning electron microscope and other microscopic characterization results as well as the results of durability study. The main reason of coating body aging is that the ester bond in fluorocarbon is easy to break, which leads to the deterioration of UV aging resistance, and during the aging of coating / mortar interface, the coating is easily crosslinked by ultraviolet irradiation for a long time. The bonding between coating molecules and mortar matrix is closer, but after UV aging reaches a certain time, the compatibility between coating and mortar interface becomes worse by continuous ultraviolet high temperature irradiation. The bonding strength between the coating and mortar decreases.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV431
[Abstract]:With the sustainable development of water resources, 172 major water conservancy projects which have been included in the planning in recent years are mainly concentrated in the central and western regions, and gradually transferred to the high altitude and cold regions of the western regions with abundant water resources. Hydraulic structures in the area generally face more complex and demanding service environments (such as high altitude, large temperature differences, strong ultraviolet radiation, Among them, freeze-thaw and ultraviolet irradiation are the most representative factors that cause damage and deterioration of hydraulic concrete structure. Therefore, the development of waterproof, weatherproof and efficient and durable surface protection coating of hydraulic concrete, which can protect concrete structure from or slow down the erosion of environmental factors, will help to improve the durability and safety of hydraulic structures at high altitude in western China. We will improve the quality of water conservancy construction and the level of operation and maintenance in China. Fluorocarbon coating has become one of the effective methods of surface protection because of its excellent low surface energy properties, corrosion resistance and weathering resistance. However, when this kind of coating is used for surface protection of hydraulic concrete, it still faces some technical problems, such as insufficient bond property and limited durability of surface interface, which limits its large-scale application. In this paper, fluorocarbon nanocomposite coatings with excellent surface hydrophobic and adhesive properties were prepared by introducing nano-materials into low surface energy fluorocarbon coatings. By analyzing the influence of coating composition and coating process on the surface interface properties, a fluorocarbon nanocomposite coating double coating system composed of fluorocarbon / nano Sio 2 coated fluorosilane surface was developed. The self-made room temperature curing fluorocarbon / nano-silica composite coating was first coated on the surface of cement mortar, and then perfluorooctyl triethoxy silane was coated on the surface of cement mortar. Through ultraviolet aging test, freeze-thaw cycle test, freeze-thawing-ultraviolet alternate cycle test and water resistance test, Fourier transform infrared spectroscopy, scanning electron microscope, contact angle test, The durability of coating material and coating / mortar system was studied by drawing test. The results show that the introduction of nano-SiO _ 2 can improve the UV aging resistance, freeze-thaw resistance and anti-freeze-thaw alternate cycle performance of the coating / mortar, and the surface durability of the coating / mortar is the best when the content of nano-SiO _ 2 particles is 10. Interfacial adhesion durability is maintained. The aging law and mechanism of coating body and coating / mortar system were preliminarily analyzed by means of Fourier transform infrared spectroscopy, scanning electron microscope and other microscopic characterization results as well as the results of durability study. The main reason of coating body aging is that the ester bond in fluorocarbon is easy to break, which leads to the deterioration of UV aging resistance, and during the aging of coating / mortar interface, the coating is easily crosslinked by ultraviolet irradiation for a long time. The bonding between coating molecules and mortar matrix is closer, but after UV aging reaches a certain time, the compatibility between coating and mortar interface becomes worse by continuous ultraviolet high temperature irradiation. The bonding strength between the coating and mortar decreases.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV431
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