中文摘要：

在正硅酸乙酯（TEOS）酸碱两步催化的溶胶-凝胶过程中，加入干燥控制化学添加剂（DCCA）N,N-二甲基甲酰胺（DMF）和三甲基氯硅烷（TMCS）的混合溶液，进行原位疏水改性处理，并结合常压干燥工艺制备了高比表面积的疏水SiO2气凝胶．利用N2物理吸附，全自动X射线衍射仪（XRD），傅立叶变换红外光谱仪（FTIR），扫描电子显微镜（SEM）等对样品的形貌结构进行了表征．实验结果表明，原位疏水改性比非原位疏水改性制备的SiO2气凝胶具有更大的比表面积，可达979m2·g^-1，气凝胶表面存在憎水性基团-CH3，有良好的疏水性．500℃热处理后，气凝胶因失去大量的-CH3基团，由憎水性转为亲水性；800℃高温热处理后，疏水SiO2气凝胶仍处于非晶态，具有良好的热稳定性能．

英文摘要：

Using an acid-base two-step catalysis for the hydrolysis of tetraethyl orthosilicate （TEOS）, hydrophobic silica aerogel with a high specific surface area was prepared by an in-situ sol-gel process and ambient pressure drying utilizing the introduction of drying control chemical additives （DCCA） N,N-dimethylformamide （DMF） and trimethylchlorosilane （TMCS） to allow for the hydrophobic modification of the sol system. The structure and morphology of these samples were characterized by N2 physical adsorption, X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectrometry, and scanning electron microscopy （SEM）. Results showed that the specific surface area of the hydrophobic silica aerogel modified by this in-situ method was larger than that of an aerogel modified by the ex-situ method. The specific surface area of the former aerogel was up to 979 m2·g-1. The aerogel had a good hydrophobic property because of the hydrophobic group （--CH3） that was linked to the aerogel＇s surface. After heat treatment at 500 ℃, the aerogel became hydrophilic because it lost most of its hydrophobic groups （--CH3）. After heat treatment at high temperature 800 ℃ the hydrophobic silica was still in an amorphous state, which indicated good thermal stability for the hydrophobic silica aerogel.