聚乙烯醇(PVA)对无支撑氧化铝膜微观结构的影响

Effects of Polyvinyl Alcohol(PVA) Content on the Microstructures of Unsupported Alumina Membranes

聚乙烯醇（ＰＶＡ）能够避免溶胶－凝胶法制备的Ａｌ２Ｏ３膜在干燥阶段产生微裂纹，同时也对Ａｌ２Ｏ３膜的微观结构产生影响．利用ＸＲＤ、ＤＴＡ、ＴＧＡ、ＦＴ－ＩＲ及Ｎ２吸附等手段研究掺杂ＰＶＡ对Ａｌ２Ｏ３膜的物相组成、热稳定性以及比表面积、孔径分布、孔表面分形性等微观结构的影响．研究表明，经过４００℃煅烧ＰＶＡ完全排除．与纯Ａｌ２Ｏ３膜相比，添加ＰＶＡ的Ａｌ２Ｏ３膜吸附量较大，比表面积有所增大，但并不随着ＰＶＡ含量的增多而增加．ＰＶＡ有利于 Ａｌ２Ｏ３膜孔径的调整，使孔径分布更狭窄，孔体积也有较大程度的增加．随着 ＰＶＡ的加入，Ａｌ２Ｏ３膜的孔表面分形维数降低．

Polyvinyl Alcohol(PVA) can prevent the microcrack of the sol-gel-derived alumina membranes from occurring during the drying process, and at the same time has effects on the microstructures of the membranes. In the present paper, the crystalline phase, thermal stability, specific surface area, pore size distribution and pore surface fractal of alumina membranes doped with PVA were characterized by XRD,DTA,DGA, FT-IR and BET. The results show that PVA is completely removed after calcination at 400 degreesC. The N(2) adsorbed amount of PVA-doped alumina membranes is greater than that of pure membranes, but doesn't increase in proportion to PVA content. The PVA-doped alumina membranes have a sharper pore size distribution, higher pore volume and lower pore surface fractal dimension.