氧化硅溶胶稳定性及其多孔凝胶的研究

以正硅酸四乙酯(TEOS)、乙醇(EtOH)和水(H2O)为原料,盐酸(H+)为催化剂,N,N-二甲基甲酰胺(DMF)为添加剂制备氧化硅溶胶.利用正交试验分析An(H2O)∶n(TEOS)]、Bn(EtOH)∶,n(TEOS)]、Cn(H+)∶n(TEOS)]、Dn(DMF)∶n(TEOS)]和E温度]5个因素(每个因素分四水平)对氧化硅溶胶稳定性的影响,以此制备稳定均匀的氧化硅溶胶.利用粒径分析解释优化因素前后溶胶稳定性的差异原因.将凝胶干燥烘焙后得到多孔材料.结果表明,对溶胶稳定性影响的强弱程度为E＞B＞A＞D、C,调整影响因素后,最好的水平组合为A(3)、B(10)、C(0.04)、D(1.6)、E(20℃),制得的溶胶粒径为10nm左右,溶胶可敞口保存35d.制备的多孔材料经理论和实验计算得孔隙率为89.33%.

Study on Stability of SiO2 Sol and Its Gel Porous Materials

Silicon dioxide sol is prepared by five materials which are TEOS, ethanol, water, hydrochloric acid and DMF, the other important factor is temperature. Orthogonal test method is employed in this experiment to explore n(TEOS)] and E(temperature) to see which are the most important factors to the stability of silicon dioxide sol(every factor is divided into four levels). Particle size analysis apparatus is used in the work to observe the main reason to the stability of silicon dioxide sol Gel porous materials are dried with the wet gel in the vacuum oven. The results show that the important factors sequence is E＞B＞ A＞ D, C, the best combination of the levels are A(3), B (10), C (0. 04),D(1. 6), E(20℃ ), the particle size is about 10nm, the stable sol could be preserved for 35 days in the open atmosphere.The porosity of the gel materials is 89. 33% after calculation and experiments.