二氧化硅溶胶稳定性的研究

二氧化硅溶胶是二氧化硅微粒分散于水中或有机溶剂中的胶体溶液, 在陶瓷、纺织、造纸、涂料、水处理、半导体等行业中有着广泛的应用。以正硅酸乙酯(TEOS)为原料, 乙醇为溶剂, 盐酸为催化剂, 用溶胶-凝胶工艺制备二氧化硅溶胶, 初步研究了溶剂、pH 值以及添加剂对二氧化硅溶胶稳定性的影响, 从而可以利用这些因素来实现对二氧化硅溶胶稳定性的控制。结果表明, 随着乙醇含量的增加, 溶胶的稳定性增加;无添加剂时, 随着pH 值的升高, 溶胶的稳定性也随之增加;在添加剂存在下, 随着pH 值增加, 溶胶的稳定性先增加后降低;加入添加剂DMF, 能使溶胶的凝胶时间延长;n (TEABr)/ n (TEOS)大于0 .05 时, TEABr 能使溶胶的凝胶时间延长。

The Stability of SiO2 Sol

The SiO_2 sol is a kind of colloid solution, with SiO_2 particle dispersing in water or organic solvents, and has been widely used in the industries of the ceramics, textile, papermaking, paint, water treatment and semiconductor and so on. SiO_2 sol was prepared from tetraethoxysilane(TEOS) by sol-gel method with ethanol as solvent and hydrochloric acid as catalyst. The effects of the solvent, the pH value, and additives on the stability of SiO_2 sol were studied during the sol-gel processing. The effects of these factors can be used to control the stability of the SiO_2 sol. The results show the more the amount of EtOH, the more the stability of sol. In the absence of additives, the stability of sol increases as the pH value is increased. As the pH value is increased, the stability of sol firstly increases, but then decreases when additives are added to the SiO_2 sol. Gelation time becomes long when DMF additive is added to the SiO_2 sol. If the mole ratio of TEABr and TEOS is more than 0.05, TEABr makes gelation time become longer.