采用溶胶-凝胶法和酸-碱两步催化过程, 以正硅酸乙酯(Tetraethyl Orthosilicate, TEOS)为前驱物, N,N-二甲基甲酰胺(N,N-dimethylformamide, DMF)为干燥控制化学添加剂、三甲基氯硅烷(Trimethylchlorosilane, TMCS)为疏水改性剂, 制得高比表面积的疏水性SiO2气凝胶. 利用X射线衍射仪(X-ray Diffraction, XRD) 、扫描电子显微镜(Scanning Electron Microscopy, SEM) 、红外光谱仪(Fourier Transform Infrared, FTIR) 、N2物理吸附仪、热重差热分析仪(Thermo Gravimetric and Differential Thermal Analyzer, TG-DTA)对样品进行了测试和表征. 结果表明：制得的疏水性SiO2气凝胶呈白色粉末状, 为非晶态的网络多孔结构, 孔径集中分布在35~40 nm之间, 且组成骨架的颗粒呈大小较均匀的球形. SiO2气凝胶表面存在大量的疏水基团—CH3, 在304.08~430. 45℃时—CH3发生氧化, 气凝胶由疏水性转为亲水性.

Based on the sol-gel method and acid-base two-step catalysis process, the hydrophobic silica aerogel with a high specific surface area is prepared by using tetraethyl orthosilicate (TEOS) as the precursors,N,N-dimethylformamide (DMF) as the drying control chemical additives and trimethylchlorosilane (TMCS) as the hydrophobic modification. The samples are tested and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrometry, N2 physical adsorption and thermo gravimetric and differential thermal analyzer (TG-DTA). The results indicate that the prepared hydrophobic SiO2 aerogel is white powder with amorphous and continuous network porous structures. The pore size of SiO2 aerogel is distributed primarily in the narrow range of 35~40 nm, and the composition of the skeleton of SiO2 aerogel is an uniform spherical particle. The hydrophobic group (—CH3) linked on the surface of SiO2 aerogel is oxidized when heated from 30408 to 43045℃, and the aerogel became hydrophilic from hydrophobic.