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利用溶胶-凝胶酸碱二步催化法和常压干燥法制备了SiO2干凝胶。反应物的配比是影响SiO2干凝胶制备最基本的因素。为了得到密度最小、孔隙率最大的SiO2干凝胶,本工作设计了一个四因素、三水平的正交实验确定水、无水乙醇、盐酸、氨水等反应物与正硅酸乙酯(TEOS)的摩尔比。同时为了保证所有实验均能在相同条件下发生,确定了其它实验参数。结果表明,SiO2干凝胶制备所需的最优反应摩尔配比为TEOS:水:无水乙醇:盐酸:氨水=1∶4∶10∶7.5×10-4∶0.0375。
SiO2 xerogels were prepared by sol-gel acid-base two-step catalysis and atmospheric drying. The ratio of reactants is the most basic factor affecting the preparation of SiO2 xerogels. In order to obtain the lowest density, the highest porosity of SiO2 xerogel, this work designed a four-factor, three-level orthogonal experiment to determine the water, ethanol, hydrochloric acid, ammonia and other reactants and tetraethoxysilane (TEOS) Of the molar ratio. At the same time, in order to ensure that all experiments can occur under the same conditions, other experimental parameters were determined. The results showed that the optimal molar ratio of TEOS to SiO2 xerogel prepared was TEOS: water: absolute ethanol: hydrochloric acid: aqueous ammonia = 1: 4: 10: 7.5 × 10-4: 0.0375.