Sol-Gel法二氧化硅溶胶的制备及性能影响研究

Preparation of Silica Sol and Effect of Preparation Conditions on Its Properties by Sol-Gel Process

以正硅酸乙酯为前驱体,硝酸为催化剂,制备了SiO2溶胶.研究了催化剂、水、乙醇的加入量对溶胶粘度和凝胶时间的影响。结果表明,在保持其它反应条件不变的情况下,随着EtOH/TEOS摩尔比的增大,溶胶粘度减小,凝胶时间变长;随着H2O/TEOS摩尔比的增大,溶胶粘度先增大后减小,凝胶时间先变短后变长,H2O/TEOS=9.6左右时粘度最大,凝胶时间最短;pH<2时,随着HNO3/TEOS摩尔比的增大,溶胶粘度增大,凝胶时间变短。

Silica sol was prepared using TEOS as the precursor and HNO3 as the catalyst by sol-gel process. The effects of the amount of catalyst, water and ethanol on the viscosity and gelation time of SiO2 sols were inspected during the sol-gel processing. The results showed that with the increasing of EtOH/TEOS molar ratio, the viscosity of sols reduced and the gelation time of sols increased. With the increasing of H2O/TEOS molar ratio, the viscosity of silica sol firstly increased and then decreased, and gelation time firstly decreased and then increased. When H2O/TEOS is about 9.6, the viscosity attained to the maximum and gelation time to the minimum. With the increasing of HNO3/TEOS molar ratio, the viscosity of sols increased and the gelation time of sols reduced when pH value is less than 2. Key words： sol-gel process ; silica dioxide; viscosity; gelation time