摘要
输电线路的积雪覆冰会对通信及电力系统网络的安全运行造成严重的威胁。覆冰常引起倒杆、断线等输电线路上的重大事故,会对其安全运行造成严重危害。因此,研究和开发输电线路相应的防覆冰技术,已成为一个重要而紧迫的课题。目前,国内外对输电线路的除冰防冰方法合计约有30余种。对输电线路的冰雪灾害,应防除并举,着重于防。因此,在输电线上涂覆超疏水的涂料,突出以防为主,力争长期高效、方便经济地解决问题,是一个较好的思路。目前构建超疏水涂层的主要方法有模板法、溶胶-凝胶法、气相沉积法等,这些方法大多制备工艺复杂或仪器成本昂贵,难以实现大面积推广。所以寻找一种成本较低,简单易行的超疏水涂层的制备方法就显得很有意义。本研究中,则是采用了的粒子填充法,将氟改性丙烯酸树脂与纳米粒子进行复合来制备了超疏水涂料,来避免传统方法繁琐复杂的制备工艺或高昂的生产成本,试图简化生产工艺并提高其性能。
本文首先采用甲基丙烯酸甲酯、丙烯酸丁酯、丙烯酸、苯乙烯与甲基丙烯酸全氟辛烷酯作为反应单体,采用自由基溶液聚合的方法,制备了氟改性丙烯酸树脂,并对合成过程中的氟单体用量、反应温度、反应单体浓度、滴加时间、玻璃化温度等工艺条件作了逐一考察,结果表明含氟单体用量为5%,反应温度为85℃,玻璃化温度为60℃,单体浓度为50%,滴加时间为2.5h时,涂膜的疏水性最佳。并对产物涂膜进行了红外图谱表征,结果表明聚合反应较完全,含氟单体完全参与到了聚合反应的过程之中。
以纳米粒子填充的方法,将纳米SiO_2与上述氟改性丙烯酸树脂进行了复合,制备了一种超疏水涂料,并探讨了纳米SiO_2的加入量对最终涂层表面疏水性的影响并分析了其形成原因。SEM测试结果表明涂层表面具有微米级的粗糙结构,且在微米粗糙结构的表面还具有纳米级的凸起。AFM测试结果表明,涂层表面分布着20nm左右的凸起不平的粗糙结构。
在试验过程中,将少量的SiO_2被纳米TiO_2所代替从而使涂层具有一定的光催化性能。考察了纳米TiO_2的加入量对涂层表面的催化性能的影响并分析了其原因。采用油渍将涂层表面污染后在紫外光照射下对涂层的自清洁性能进行了考察,结果表明,涂层对其表面污物具有一定的分解与自清洁能力,使涂层的超疏水性在一定程度上有所恢复,有利于操持涂层疏水性的持久性,增加其实际利用价值。在覆冰模拟实验中,对不同基材与覆冰之间的粘附力进行了测量并进行了逐一对比。结果表明疏水性的不断增加会使覆冰的粘附力逐渐下降。当涂层具有超疏水性时,其与表层覆冰之间的粘附力比常见玻璃基材下降了80%左右,显著提高了其抗覆冰性能。
综上所述,采用粒子填充法制备的超疏水涂层,相对于其他方法而言简单易行,成本较低,可操作性强,同时纳米TiO_2的加入使涂层具有一定的自清洁性能,有利于保持其疏水性的长久性。被该涂料涂覆后可明显降低基材与表层覆冰之间的粘附作用力,为防止输电线路覆冰自然灾害提供了一条可行的思路。
The security of electricity and communication network was threaten by the ice and snow on the transmission line. The ice can cause the collapse of transmission lines, flashover insulator and other major incidents, so the safe operation of the power system have serious hazards. Therefore, the research and development of anti-icing thchnology for transmission lines has become an important and urgant tasks. Currently, the methods of anti-icing on the transmission line have about 30 species. On the transmission line disater, the facus should be placed on prevention and control. Therefore, the transmission lines coated with the super-hydrophobic coating can strive to long-term efficient, convenient and economical solution the problem is a good idea. Currently, the main method to construct the super-hydrophobic coating have template, sol-gel, vapor deposition and so on, but most of these methods need complex preparation or extensive eauipment and are difficult to be supplied in large area. So, the rsearch for a low cost and simple preparation method of super-hydrophobic coating becomes very significant. In this work, the super-hydrophobic coating was prepared by particle-filling method based on nanometer SiO_2 and TiO_2 as fillers, fluoropolyacrylate as binder. The method avoid cumbersome traditional methods of complex preparation process or high production costs, and trying to simplify the produciton process and improve the coating’s performance.
In this paper, methyl methacrylate, butyl acrylate, acrylic acid styrene and fluorine-containing monomer were used to prepare the fluoropolyacrylate by the free radical copolymerization. The amount of fluorine monomer, reaction temeprature, monomer concentration, addition time and the glass transition temperature were investigated on the synthesis, the results showed that when the amount of fluorine monomer was 5%, reaction temperature was 85℃, monomer concentration was 50%, addition time was 2.5h and glass transition temperature was 60℃, the products had the best hydrophobicity.The characterization of the product by IR showed that the the polymerization reaction is complete and the fluorine-containing monomer was fully involved in the reaction.
The super-hydrophobic coating was prepared by particle-filling method based on nanometer SiO_2 as fillers and fluoropolyacrylate as binder. The impact of the added amount of nanometer SiO_2 on the final surface hydrophobicity was explored and the causes were analyzed. The characterization of the product by SEM showed that the surface of coating exhibited a crater-like topology composed of processes and holes with diameter of 500nm. The AFM showed the asperity shapes and density of the rugosities with diameter of 20nm distributed on the particle surface.
In this work, a little amount of nanometer SiO_2 was replaced by nanometer TiO_2 to make the coating has photocatalyticity. The impact of the added amount of nanometer TiO_2 on the photocatalyticity was explored and the causes were analyzed. The surface of coating was smeared by oil pollutant and then dried. The changes of CA on the oil pollutant surface under a low pressure mercury lamp were determined as a function of irradiation time. The results indicated that the photocatalytic degradation of the oil could regenerate the hydrophobic surface. It meant that the small amounts of n-TiO_2 mixed in the coating could puriy the attached oil pollutants under UV light irradiation and enhance its use value.
In the simulation of ice, adhere force of faces of different hydrophobicity and ice was measured one by one. The results indicated that the increase of hydrophobicity can reduce the force. When the coating had super-hydrophobicity, the adhere force can drop about 80% and the performance of anti-ice improved significantly.
In summry, the preparation of super-hydrophobic coating by particle-filling method was simple and had low coat, high maneuverability. The addition of nanometer TiO_2 made the coating has performance of self-cleaning which was conducive to maintaining the longevity of its hydrophobicity. After being coated with this super-hydrophobic coating, the adhere force between ice and substract can be decreased obviously. Therefore, this work provides a feasible way of think to prevent natural disasters of transmission line.
引文
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