SiO_2无机膜涂膜液稳定性的研究

Study on Stability of the SiO_2 Sol for Inorganic Membranes

制备SiO2溶胶作为SiO2无机膜的涂膜液，以正硅酸乙酯（TEOS）、水为原料，乙醇（EtOH）为溶剂，N，N-二甲基甲酰胺（DMF）为添加剂，盐酸（HCl）为催化剂。先后用正交实验法和单因素实验研究了乙醇、水、DMF、pH值和配制温度对SiO2溶胶稳定性的影响，结果表明：pH值影响因素中占权重最大；其次为水，随着水量的增大溶胶的稳定时间明显变长，比值在12～14；随着乙醇含量的增加，溶胶稳定性的增长速率由快变慢，n（EtOH）／n（TEOS）保持在16～20；DMF对其影响不大；而配制温度的影响在单因素实验中得到体现。

Silica sol as coating liquid for the inorganic SiO2 membranes was prepared by using tetraethoxysilane （TEOS） and H2O as the raw materials, ethanol as solvent, DMF as additive and hydrochloric acid as catalyst. Orthogonal test design method and single factor experiment were used to study the effects of the EtOH, H2O, DMF, pH value and preparing temperature on the stability of SiO2 sol. The results show that the pH value has most significant influence among these factors; H2O has the secondly important impact; the stabilization time becomes obviously longer with increasing the ratio of it. The best ratio is about 12- 14. The sol stability rises fast and gradually slowly as EtOH is increased; n （EtOH）/n（TEOS） remains about 16-20; DMF has little influence on it, but the effect of preparing temperature was shown in single factor experiment.