酸性硅溶胶稳定性的正交实验

以正硅酸乙酯（TEOS）为原料，乙醇为溶剂，硝酸为催化剂，聚乙烯吡咯烷酮（PVP）为添加剂，采用溶胶一凝胶工艺制备二氧化硅溶胶．利用正交试验研究水、正硅酸乙酯、乙醇、酸碱度（pH）、PVP以及反应时间对二氧化硅溶胶稳定性的影响．结果表明，制备硅溶胶的最佳工艺条件为：水与正硅酸乙酯的摩尔比为8，乙醇与正硅酸乙酯的摩尔比为14，pH值为2，PVP的加入量为0，反应时间为50分钟．对于硅溶胶稳定性的影响，乙醇与正硅酸乙酯的摩尔比最为显著，随着乙醇与正硅酸乙酯的摩尔比的增加，溶胶的稳定性增强；随着PVP用量的增加，溶胶的稳定性降低；同时，pH值的增大和反应时间的延长有利于溶胶的稳定性增强．

Orthogonal test of acidic silical sol stability

Silica sol was prepared using tetraethyl orthosilicate （TEOS） as raw mateials, Anhydrous ethanol （EtOH） as solvent,nitric acid as catalyst and Polyvinylpyrrolidone （PVP） as additives by sol- gel method. The orthogonal test was used to study the effects of water, EtOH, TEOS, pH, quality addition of PVP and reaction time on the silica sol stability. The results show that the best preparation conditions for silica sol are that the mole ratio of water to TEOS of 8, the mole ratio of EtOH to TEOS of 14, pH of 2, quality addition of 0 and reaction time of 50 rain. The mole ratio of EtOH to TEOS exhibits significant effect in the silica sol stability, the silica sol stability increases with the increasing mole ratio of EtOH to TEOS. PVP makes the gelation time become short. At the same time, sol stability increases with the pH and the reaction time increasing.