高性能气凝胶保温隔热材料的常压制备与性能研究

发布时间：2018-01-15 08:31

本文关键词：高性能气凝胶保温隔热材料的常压制备与性能研究　出处：《广州大学》2014年硕士论文　论文类型：学位论文

【摘要】：SiO2气凝胶是一种具有超低热导率、超低密度、高孔隙率和高比表面积等特点的轻质纳米固态材料，但其本身的强度低、脆性大及生产成本高等原因限制了SiO2气凝胶在建筑保温隔热领域上的应用。而常用保温隔热材料或是高导热系数、吸湿性强或是耐燃性能差的原因限制了其在当今建筑保温隔热领域上的广泛使用。针对SiO2气凝胶和常用保温隔热材料的特点，本文采用正硅酸乙酯为硅源，以玻璃棉毡、玻璃针刺毡为增强相，通过溶胶－凝胶整体成型及常压干燥工艺制备出一系列的玻璃纤维/SiO2气凝胶复合材料。在常压干燥工艺中，通过对复合凝胶两步法和一步法制备工艺研究，确定了对复合凝胶的一步溶剂交换－表面改性处理工艺，并采用扫描电镜、热常数分析仪、热重分析仪、光学接触角测量仪和电子万能试验机等分别对玻璃纤维/气凝胶复合材料的微观结构、导热系数、热稳定性、疏水性能及力学性能进行了测试。结果表明通过把SiO2气凝胶与玻璃纤维毡复合，制得的复合材料具有低导热系数、高疏水性、较高的力学性能及耐温性能等特点。同时，多步溶剂交换－表面改性法与一步溶剂交换－表面改性法两种处理方法所得的复合材料的各项性能较为接近：采用多步溶剂交换－表面改性法所得的玻璃棉毡/SiO2气凝胶复合材料的导热数系数为0.024W m-1K-1，静态接触角为124o，，抗拉、抗压和抗弯强度由复合前的0.002、0.011和0.011MPa提高到0.213、1.474和0.252MPa。而对于玻璃针刺毡/SiO2气凝胶复合材料，其导热系数仅为0.025W m-1K-1，接触角为112o，抗拉、抗压和抗弯强度则均在1MPa以上。改性液的配比为EtOH: TMCS:正已烷＝2:2:26时与原配比EtOH: TMCS:正已烷＝1:3:26所得复合材料的导热系数均为0.022W m-1K-1，力学性能也很接近；对于不同气凝胶添加量对复合材料性能的影响，当玻璃棉与玻璃棉毡/SiO2气凝胶的质量比为13%时，具有较好的综合性能及经济性，此时复合材料的导热系数为0.023W m-1K-1、接触角为127°，抗拉、抗压和抗弯强度分别为0.132、1.563和0.282MPa；另外，配比中无水乙醇量的增加对复合材料的导热系数没有影响，而随着配比中无水乙醇的量的增加，复合材料的密度和力学性能逐渐降低，当无水乙醇量为原配比的2倍时，其密度低至148kg/m3。
[Abstract]:SiO2 aerogel is a kind of ultra low thermal conductivity, low density, lightweight nano solid materials with high porosity and high surface area characteristics, but its low strength, brittleness and high production cost reasons limit the SiO2 aerogel in application of thermal insulation in the field of building insulation and thermal insulation materials or used. High thermal conductivity, strong moisture absorption or burning resistance causes poor performance limits its wide use in the field of heat insulation. In today's architecture for SiO2 aerogel and used thermal insulation materials, using TEOS as silicon source, the glass wool felt glass mat reinforced by. Sol gel forming and whole atmospheric drying preparation process of glass fiber /SiO2 aerogel composite material. In a series of ambient pressure drying process, through the study on Preparation of composite gel two step method and one step method, are determined. The one step solvent composite gel exchange surface modification process, and using scanning electron microscopy, thermal constant analyzer, thermogravimetric analyzer, optical contact angle measuring instrument and electronic universal testing machine of glass fiber / aerogel composite material microstructure, thermal conductivity, thermal stability, and mechanical properties of hydrophobic the test.
The results show that the SiO2 aerogel and glass fiber composite, the composite materials with low thermal conductivity, high hydrophobicity, mechanical properties and heat resistance characteristics such as high. At the same time, the performance of multi - step solvent exchange surface modification method and one-step solvent exchange surface modification method of the two processing method of composite materials is close to: a multi step solvent exchange surface modification method of glass wool felt /SiO2 aerogel composite material thermal conductivity coefficient is 0.024W m-1K-1, static contact angle is 124o, tensile, compressive and flexural strength of the composite before 0.002,0.011 and 0.011MPa increased to 0.213,1.474 and 0.252MPa. for the glass mat /SiO2 aerogel composite material, its thermal conductivity is only 0.025W m-1K-1, the contact angle is 112O, tensile, compressive and bending strength is above 1MPa.
Modified liquid ratio of thermal conductivity of 1:3:26 composites produced are 0.022W = m-1K-1 EtOH: TMCS: = 2:2:26 and n-hexane than original EtOH: TMCS: n-hexane, the mechanical properties are also very close; for different aerogels addition effect on the properties of the composite materials, when glass wool and glass wool felt /SiO2 aerogel quality when the ratio is 13%, with comprehensive performance and good economy, the thermal conductivity of the composite was 0.023W m-1K-1, the contact angle is 127 DEG, tensile, compressive and flexural strength were 0.132,1.563 and 0.282MPa; in addition, absolute ethyl alcohol ratio increase in the thermal conductivity of composite materials has no effect, and with the the increase in the volume ratio of ethanol, the density and the mechanical properties of the composites decreased gradually, while 2 times amount of ethanol as raw ratio, the low density of 148kg/m3.

【学位授予单位】：广州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU551

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