SiO_2浓度对反应体系成胶特性及SiO_2凝胶粉末性能的影响

Effect of SiO 2 Concentration on the Characteristic of Sol Gel Formation and the Property of Silica Gel Powders

以水玻璃为原料，乙酸乙酯为潜伏酸试剂，采用溶胶－凝胶法制备超细二氧化硅凝胶粉末．研究了成胶反应体系中的ＳｉＯ２浓度对成胶特性及最终所得二氧化硅凝胶粉末性能的影响，并用透射电镜和氮气物理吸附测试手段对粉末的有关性能进行了测试和表征．结果表明：增大ＳｉＯ２浓度，反应体系成溶胶时间和成凝胶时间逐渐减小；最终所得ＳｉＯ２凝胶粉末颗粒粒径逐渐变大，总孔体积单调降低，颗粒间聚集形成的孔明显减少．

Ultrafine silica gel powders were prepared by means of sol gel method from water glass using ethyl acetate as a latent acid reagent. Both of the effect of silica concentration in the sol gel process on the characteristic of silica sol gel formation and the property of silica gel powders obtained were investigated. The products were characterized by TEM and nitrogen adsorption. The results show that with increasing silica concentration, the time of silica sol gel formation is gradually reduced, at the same time, the size of silica gel powders obtained is increased by degrees, the total pore volume decreased montonously and the amount of pores formed by aggregation of particles diminishe dramatically.