疏水SiO_2气凝胶的常压制备及在建筑隔热涂料中的应用

Preparation of Hydrophobic SiO_2 Aeroge under Ambient Pressure and Its Application in Heat-Insulating Architectural Coatings

以廉价的工业级正硅酸乙酯为原料,经过酸碱两步催化制备二氧化硅凝胶,分别以三甲基氯硅烷(TMCS)/六甲基二硅氧烷(HMDSO)溶液和TMCS/n-C6H14溶液对凝胶进行改性,常压干燥下制得产品。用FT-IR、TEM、XRD等手段对样品进行表征,并考察了产品的疏水性能和在外墙涂料中的隔热性能。在相同的条件下,前者可以使凝胶溶剂交换和表面改性同时完成,而后者则不能。以TMCS/HMDSO改性所得产品为无定型非晶态结构,具有5～10 nm孔径。改性后的SiO2气凝胶具有较强的疏水性,在外墙建筑涂料中具有优良的隔热性能。

The title silica gel was prepared by two -step acid -base catalysis process using low cost industrial tetraethyl orthosilicate as precursor, the gel was modified by TMCS/HMDSO solution and TMCS/n - C6Hl4 solution respectively, which was then dried at ambient pressure. The products were characterized by use of FT - IR, TEM and XRD. The hydrophobic performance and heat insulation properties in exterior wall coatings were investigated. Under the same condition, the solvent exchange and surface modication on the former surface could be completed simultaneously, but impossible for the later form. The product modified by TMCS/HMDSO solution was in an amorphous state and had a pore diameter of 5 - 10 nm. The modified SiO2 aerogel had good hydrophobic and heat -insulating properties in exterior wall coatings.