摘要：

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

关键词: 疏水性, 二氧化硅, 共聚法, 常压干燥

Abstract:

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.

Key words: 疏水性, 二氧化硅, 共聚法, 常压干燥