The hydrophobic silica aero-gels were prepared by copolymerization under ambient pressure, and sol-gel two-step catalysis. Tetraethoxysilane (TEOS) was used as precursor, methacrylic propenyl trimethoxy silane (KH-570) was used as modifier and ethanol (EtOH) was used as solvent. To establish the reaction mechanism and confirm the preparation process steps, in-situ IR was used to monitor the process on line. The pore size distribution, microstructure, surface functional groups and thermal stability were investigated with SEM, BET, FTIR and TG-DSC. The results showed that silica aero-gels modified with KH-570 exhibited good hydrophobic performance with surface area of 877.17 m2 · g-1. This material was composed of accumulated spherical nano-particles. The particle size was in the range of 10-50 nm and the pore size was 1.9-2. 5 nm. It was typical nano-mesoporous material.%以正硅酸乙酯为原料,应用溶胶-凝胶两步催化,甲基丙烯酸基丙基三甲氧基硅烷作为改性剂,无水乙醇为溶剂,共聚法常压下制备疏水性SiO2气凝胶.运用原位红外在线监测反应历程,确定制备工艺步骤.运用N2吸附仪、扫描电镜、红外光谱、TG-DSC对SiO2气凝胶孔径分布、形貌、表面官能团及热稳定性进行分析.结果表明,经甲基丙烯酸基丙基三甲氧基硅烷改性的SiO2气凝胶疏水性能良好,疏水的耐温性可达到407℃,比表面积为877.17 m2·g-1, 由球形纳米颗粒堆积而成,颗粒尺寸范围在10～50 nm,孔径集中分布在1.9～2.5 nm,是典型的纳米介孔材料.
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