二氧化硅气凝胶最佳制备工艺的确定

Determination of the Best Preparation Craft of Silica Aerogel

以正硅酸乙酯为原料,先采用溶胶-凝胶法制备湿凝胶,然后浸泡在反应溶液中进行老化,再利用正己烷进行溶剂交换,三甲基氯硅烷进行表面改性,最终获得轻质多孔二氧化硅气凝胶。并通过正交试验,确定了制备凝胶的最佳工艺条件是:pH=5,TEOS∶乙醇∶水(摩尔比)=1∶4∶8;利用FTIR、XRD和SEM等方法对二氧化硅气凝胶改性特征和添加DCCA前后的物理性质进行表征。

Using tetraethoxysilane（TEOS） as the silica source, silica aerogels were synthesized via sol -gel and am- bient drying process. In order to enhanced the wet gel, measures such as prolonging aging time, exchanging solvent and using an trimethylchlorosilane（TMCS）/hexane modification were adopted. The synthesized silica aerogel was a light, por- ous and crack -free solid. Through the orthogonal experiment, the determined preparation gelatin best technological con- ditions were pH =5, and TEOS ： EtOH ： H20（摩尔比） = 1 ： 4 ： 8. Using FTIR, XRD and SEM and other methods, the modification of silica aerogel properties and physical properties before and after adding DCCA were characterized.