以TEOS-40为硅源，通过酸碱两步法，以六甲基二硅氮烷为改性剂，经CO2超临界干燥制备具有疏水性质的SiO2气凝胶，对其进行比表面积和孔径、微观形貌、光学角、导热、傅里叶红外及热重分析，研究改性剂添加量（0、0.05、0.1、0.2、0.4mol）对SiO2气凝胶结构和性能的影响。结果表明，使用六甲基二硅氮烷作为改性剂制备的气凝胶性能更优。当使用改性剂量为0.2mol时，得到的SiO2气凝胶性能最好，密度0.1056g/cm3，疏水性优良，接触角138.2°，BET比表面积1066.1568m2/g，平均孔径18.0705nm。在1um下，微观结构最好，孔径最大，分布最均匀；导热低至0.0194W/m·k，且在350℃之前有良好的热稳定性。

In this paper, hydrophobic silica aerogels are prepared by supercritical drying, using tetraethyl orthosilicate (TEOS-40) as the precursor, hexamethyldisilazane as the modifier, and acid base two-step method. The effects of the amount of modifier (0, 0.05, 0.1, 0.2, 0.4mol) on the structure and properties of silica aerogels are studied by means of specific surface area and pore size, micro morphology, optical angle, thermal conductivity, Fourier transform infrared spectroscopy and thermogravimetric analysis of the prepared aerogels. The results show that the aerogel prepared by the modification of hexamethyldisilazane has good performance, and when the modifier dosage is 0.2mol, the modified silica aerogel obtains the best performance, density 0.1056g/cm3, excellent hydrophobicity, contact angle 138.2°, BET specific surface area 1066.1568m2/g, and average pore diameter 18.0705nm. At 1um, the microstructure is the best, the pore diameter is the largest, the distribution is the most uniform, the thermal conductivity is as low as 0.0194W/m·k, and it has good thermal stability before 350℃.

TQ427

枣庄市自主创新及成果转化计划项目“耐高温气凝胶保温材料中试制备技术研发与示范”（2020GH20）