【作者】 夏志伟；

【导师】 吴笑梅；

【作者基本信息】 华南理工大学 ， 材料学， 2015， 硕士

【摘要】 随着人们对居住环境舒适度要求的越来越高,采暖与制冷装置越来越普及,建筑节能日益受到人们的关注。提高建筑物的保温隔热性能是一种重要的建筑节能措施。反射隔热涂料作为一种新型的建筑材料,不仅能起到装饰美化的作用,还具备良好的隔热效果,能有效提高南方炎热地区夏季室内的舒适度,降低建筑物空调能耗。反射隔热涂料的关键技术在于反射隔热颜料的制备。粉煤灰空心玻璃微珠具有中空结构、颗粒尺寸小、质轻、导热系数小、保温效果好,Ti O2具有折射率大、对近红外线反射率高的特点。如在玻璃微珠表面包覆一层纳米Ti O2薄膜,可以使其同时具备良好的隔热性能和高的近红外反射率,制备出一种集阻隔隔热和反射隔热功能于一体的复合隔热材料。目前在制备玻璃微珠-Ti O2复合颗粒方面仍存在一些未妥善解决的难题,主要表现为玻璃微珠表面二氧化钛薄膜包覆率低、薄膜包覆不均匀,易出现游离二氧化钛等,既影响隔热效果,也造成大量的二氧化钛浪费。这主要与玻璃微珠的表面特性有关,因此研究不同的包覆方法、不同的玻璃微珠表面预处理技术就显得尤为重要。本文分别用溶胶-凝胶法和非均相沉淀法在玻璃微珠表面包覆纳米Ti O2薄膜,研究溶胶-凝胶法中的钛盐浓度、p H值、静置时间、煅烧温度等反应条件对包覆效果的影响;非均相沉淀法中预处理方式对玻璃微珠表面组成、微结构和二氧化钛薄膜包覆的影响,并对包覆过程和包覆机理进行了探讨,最后对所制备的样品的隔热性能进行研究。研究结果表明:(1)溶胶-凝胶法制备Ti O2-HGM过程中,溶胶静置时间延长,包覆率提高,包覆均匀性降低。钛盐浓度影响薄膜的连续性,钛盐与乙醇摩尔比在15~20范围内成膜效果好。p H值影响溶胶的稳定性,适宜的溶胶p H范围为2~4。凝胶在600℃煅烧转变为锐钛矿型二氧化钛。(2)非均相沉淀法制备Ti O2-HGM过程中,HF、Na OH、Ca(OH)2对玻璃微珠预处理,玻璃微珠表面Ti O2包覆率和均匀性提高。表面活性剂预处理玻璃微珠后其表面Ti O2薄膜的均匀性提高。用Ca(OH)2对玻璃微珠进行预处理,表面有CSH生成,该层物质能有效抑制Ti O2薄膜煅烧开裂。Ca(OH)2预处理24小时可以得到包覆率最高、表面无裂纹、保温隔热效果好的样品。(3)HF、Na OH、Ca(OH)2对玻璃微珠预处理后,玻璃微珠的比表面积提高和Zeta电位下降。玻璃微珠与Ti O2.n H2O带同种电荷,静电排斥,不利于包覆,玻璃微珠与Ti O2.n H2O带异种电荷,静电吸引,促进包覆。玻璃微珠表面包覆Ti O2受到玻璃微珠的比表面积和Zeta电位共同影响。二氧化钛在玻璃微珠表面沉积过程表现为层状生长模式。(4)将Ti O2包覆在玻璃微珠表面其隔热效果要优于Ti O2与玻璃微珠直接混合。溶胶-凝胶法制备的Ti O2-HGM在8.2%的Ti O2包覆率下,隔热温差为11.8℃。非均相沉淀制备Ti O2-HGM最大包覆率为28.6%,隔热温差为27.6℃。更多还原

【Abstract】 With high demand for comfort of the living environment, The application of air conditioner equipment gets more and more popular. Energy-saving of building draw many people’s attention. Improving the heat insulation properties of buliding is an Important measures of energy conservation. As a type of new constructional material, heat insulation coating can applicat to beautify ande strew people’s life, and has excellent heat insulation properties. It is an effective measure to reduce energy consumption of air conditioning and to improve the comfort of living environment. Important Function of heat insulation coating Made up of reflective powder. Hollow glass microspheres(HGM) have the following characteristics: small particle size, hollow structures, light mass and little heat conductivity. Ti O2 has characteristics of high refractive index. If coating Ti O2 films on the surface of HGM, Material with properties of good heat insulation and high refractive index can be obtain. However, Some problems still exist on preparation of Ti O2-HGM, such as hard to get high cladding rate, easy to Appear free Ti O2. That’s bad for heat insulation and wastes Ti O2. Surface properties of HGM contribute to this. To study the influence of sample preparation method to HGM and adopt new method of preparation has important implications.In this paper the films were coated by sol-gel process and heterogeneous deposition process. The influences of the follow reactive conditions were studyed : titanium concentration, standing time, p H values, calcining temperature. The effect of pretreatment methods to the composition and structure of HGM, and to the coat effect of Ti O2 were studied in this paper. Then the mechanism of heterogeneous deposition process was discussed briefly,Finaly heat preservation performance of Ti O2-HGM studied in this paper.The results shows as follows:(1) As the retention time of sol increase, coating rate improved, depositing uniformity decreased, the suitable retention time are 8~12 hour. titanium concentration must have an effect on continuity of Ti O2 film, The optimal molar ratio of Ti4+ to Ethanol was 1:15 ~1:20. p H have serious influence on stability of the sols and coating rate. p H need to be controlled between 2~4. Anatase titanium dioxide transferred at temperature of 600℃.(2) Ti O2 coated on the surface of HGM which Pretreated by HF, Na OH, Ca(OH)2. All of the three preprocess methods can improve the coating rate effectively. Glasses dissolved and The substrate roughness increase when HGM pretreatment by HF and Na OH. Uniformity of thin films gets better when HGM pretreated with CBTA and SDBS. CSH appears on the surface of HGM pretreated by Ca(OH)2 at 90℃. The new product layer can prevent cracking of Ti O2 film. The sample of highest coating rate, crack-free of Ti O2 film and best heat preservation effect can be obtained.under the condition of HGM pretreated with Ca(OH)2 at 90℃.(3)The zeta potential and surfactants of HGM changed after pretreated by HF、Na OH、Ca(OH)2. Both of zeta potential and surfactants function to Ti O2 growing on the surface of HGM. At the initial stage, Island particles growth on the surface of HGM. Nano particles grow and agglomeration with time, then film formatted. Step growth models were clearly shown.(4) The experimental results show heat preservation properties of Ti O2-HGM is better than Ti O2 and HGM physical blend into coating. The coating rate of Ti O2-HGM prepare by sol-gel is 8.2%, and the temperature difference is 11.8℃. The coating rate of Ti O2-HGM prepare by heterogeneous deposition method is up to 28.6%, and the temperature difference is 27.6℃.更多还原