摘要SiO2气凝胶作为一种超级隔热材料，以其极高的孔隙率和极低的热导率受到广泛关注，但其制备工艺的复杂性也制约了它的发展。本文研究了一种低成本简单工艺制备二氧化硅气凝胶的方法，将廉价水玻璃作为硅源，通过溶胶-凝胶工艺、陈化工艺、表面改性等一系列操作，最后经过常压干燥得到SiO2气凝胶样品。实验主要研究水玻璃的稀释度、pH值、干燥条件等因素对气凝胶状态的影响，同时对不同的陈化时间和表面改性剂TMCS的加入量进行探索。实验最终确定：水玻璃以1：15稀释，pH值为7制备湿凝胶，静置3d，溶剂交换3d，再以V水玻璃：VTMCS：V正己烷=1：1：10的比例进行表面改性处理，最后将凝胶浸泡于正己烷、无水乙醇混合液中处理后70℃干燥。80996

由于SiO2气凝胶的脆性，其在加工和处理等方面存在一定的难度，从而制约了结构应用等方面的发展。为了较好的解决这一问题，提高SiO2气凝胶的适用性，可以通过发泡法将疏水性SiO2气凝胶颗粒混合进明胶-SDS（十二烷基磺酸钠）发泡溶液中的，制备出明胶二氧化硅气凝胶（GSA）复合块，即GSA-SDS复合材料。由于实验条件与周期的限制，前期制备的SiO2气凝胶量较少，遂用疏水的气相二氧化硅和沉淀二氧化硅来替代SiO2气凝胶。实验主要确定了SDS与水含量相同时， 明胶与气相SiO2的比例为1。5：8。5、2：8、2。5：7。5、3：7、3。5：6。5，明胶与沉淀SiO2的比例为1。1：8。9、1。4：8。6、1。7：8。3、1。9：8。1、2。2：7。8。经性能测试，可知明胶/气相SiO2复合材料的密度更小、保温效果更好，但其阻燃性略差。

毕业论文关键词： 水玻璃；SiO2气凝胶；明胶；二氧化硅；复合材料

Abstract SiO2 aerogels as a super-insulation material, with its high porosity and very low thermal conductivity has been widely concerned, but the complexity of its preparation process also restricts its development。 In this paper, a low-cost simple process for the preparation of silica aerogels was studied。 A series of operations such as sol-gel process, aging process and surface modification were used as the silicon source。 Dry to obtain a sample of SiO2 aerogels。 The effects of dilution, pH value and drying conditions on the aerogel state were studied in the course of the experiment, and the different aging time and the amount of TMCS were explored。 The final determination of the water glass to 1:15 dilution, pH 7 prepared wet gel, standing for 3 days, solvent exchange 3 days, then V water glass: VTMCS: V n-hexane = 1 : 1: 10 ratio of the surface modification treatment, and finally the gel immersion in n-hexane and anhydrous ethanol mixture after treatment at 70 ℃ dry。

Due to the brittleness of SiO2 aerogels, there are some difficulties in processing and handling, which restricts the development of structural applications。 In order to solve this problem and improve the suitability of the SiO2 aerogel, the hydrophobic SiO2 aerogels can be mixed into the gelatin-SDS (sodium dodecyl sulfonate) foaming solution by the foaming method, A mixture of gelatin silica aerogels (GSA) composite, GSA-SDS composites was prepared。 Due to the limitation of the experimental conditions and the cycle, the amount of SiO2 aerogels prepared in the early stage is less, and the hydrophobic fumed silica and precipitated silica are used to replace the SiO2 aerogels。 The experiment mainly determined that the ratio of gelatin to gas phase SiO2 was 1。5: 8。5, 2: 8, 2。5: 7。5, 3: 7, 3。5: 6。5, and the ratio of gelatin to precipitated SiO2 was 1。1: 8。9, 1。4: 8。6, 1。7: 8。3, 1。9: 8。1, 2。2: 7。8, when SDS and water content of the same。 The performance test shows that the density of gelatin / vapor-phase SiO2 composites is smaller and the insulation effect is better, but the flame retardancy is slightly worse。