甲基纤维素对SiO2薄膜性能的影响

摘要

以正硅酸乙酯为主要原料,采用溶胶凝胶法和浸渍提拉技术在氧化铝支撑体上进行涂膜,研究了在制备过程中引入甲基纤维素(MC)对SiO2薄膜性能的影响.采用FT-IR和AFM、BET等测试技术对膜的热稳定性、凝胶膜热处理前后的结构变化和薄膜的表面微观形貌进行表征.实验结果表明,甲基纤维素对SiO2溶胶体系起到增稠剂的作用,本次实验确定的最佳加入量为每100 mL溶胶中加入0.35g甲基纤维素；SiO2薄膜表面光滑平整,内部结构均匀,具有良好的热稳定性；但与未加入甲基纤维素的薄膜相比较,薄膜的孔隙率和平均孔径均有一定的减少；SiO2薄膜的孔径分布呈单峰且较窄,其最可几孔径为1.14 nm;添加甲基纤维素后的薄膜在0.18 MPa下,纯水通量为880 L/(m2·h);孔隙率约为31％,体积密度为2.4％.%A silica gel was prepared on the supporting body of alumina by sol-gel process and dip-coating technique using tetraethoxy silicone(TEOS) as main raw material, then a SiO2membrane was introducted by methyl cellulose. The structures and properties were effected by adding methyl cellulose. The thermal stability, phase transformation, structure and morphology of composite membranes were characterized by FT-IR、AFM、 BET, etc. respectively. The results showed that the methyl cellulose played a role of thickening agent on SiO2 sol system. When the SiO2 sol was 100 mL, the optimum adding amount of methyl cellulose was 0.35 g. The films surface was smooth, uniform internal structure and had good thermal stability. The porosity and average pore size of the thin film can be reduced compared with that there is no adding methyl cellulose film; The pore size distribution of SiO2films were unimodal, narrow and the most probable pore diameters were about 1. 14 nm; The pure water flux of the film added was 880 L/ (m2 · h); porosity was about 31%, and volume density was 2. 4% under 0. 18 MPa.