多次疏水改性SiO_2气凝胶的制备及其性能表征

Preparation and Performance Characterization of SiO_2 Aerogel by Multi-Hydrophobic Modification

以正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTOS)为共聚硅源,加入N,N-二甲基甲酰胺(DMF)为化学干燥控制添加剂,三甲基氯硅烷(TMCS)和γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)为原位疏水改性剂,通过溶胶-凝胶法,常压干燥制备出低密度的疏水SiO2气凝胶。用扫描电子显微镜(SEM)、N2-吸附仪、傅里叶变换红外分析(FT-IR)、X射线衍射、热分析仪对其结构和性能进行表征。结果表明:所制备出的SiO2气凝胶比表面积高达870.99 m2/g、孔体积为1.74 cm3/g,密度为0.244 g/cm3,气孔率为88.9%,可在430℃下保持疏水性,孔径分布集中在11 nm,为典型的中孔纳米材料。

The hydrophobie SiO2 with low density aerogel was prepared using tetraethoxysilane （TEOS） and methyltriethoxysilane （MTOS） as co-polymer Si source, N,N-dimethylformamide （DMF） as chemical drying controlling additive, trimethylchlorosilane （TMCS） and γ-methylpropenoyloxypropyl trimethoxylsilane （KH-570） as situ hydrophobic modifier by sol-gel method and drying under ambient pressure. Its structure and performance were characterized by using scanning electron microscopy （SEM）, N2-adsorption apparatus, Fourier infrared （FT-IR）, X-ray diffraction and thermal analysis instruments. The results show that the specific surface area of the prepared SiO2 aerogel is up to 870.99 m2/g, the pore volume is 1.74 cm3/g, the density is 0.244 g/cm3, the porosity is 88.9%, the hydrophobic performance can be maintained even at 430 %, the pore size distribution is focused on 11 nm. The SiO2 aerogel is typical mesopore nano material.