Novel thermally cross-linked polyimide membranes for ethanol dehydration via pervaporation

作者：Xu, Sheng; Wang, Yan^*

来源：Journal of Membrane Science, 2015, 496: 142-155.

DOI：10.1016/j.memsci.2015.08.055

• Pcrvaporation membrane
• Carboxyl-containing polyimide
• Thermal treatment
• Cross-linking
• Ethanol dehydration

In this work, two novel carboxyl containing polyimicles, 2,2'-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride-4,4'-diaminodiphenylmethane/3,5-diaminobenzoic acid (GFDA-MDA/DABA, FMD) and 3,3',4,4'-benzophenone tetracarboxylic dianhydride-4,4'-diaminodiphenylmethane/3,5-diaminobenzoic acid (BTDA-MDA/DABA, BMD), are synthesized via chemical and thermal imidization methods, respectively, and employed as pervaporation membranes for ethanol dehydration. Chemical structures of the two polyimides are examined by FUR and TGA to confirm the successful synthesis. A post thermal treatment of the polyimide membranes with the temperature range of 250 to 400 degrees C is applied, and its effects on the membrane morphology and separation performance are studied and characterized by FTIR, TGA, WXRD, solubility and sorption test. It is believed that the thermal treatment of the carboxyl-containing polyimide membrane at a relative low temperature only leads to the physical annealing, while it may cause the decarboxylation-induced cross-linking at a higher temperature. In addition, the operation temperature in pervaporation is also varied and shown to be an important factor to affect the final membrane performance. Performance benchmarking shows that the developed polyimide membranes both have superior pervaporation performance to most other flat-sheet dense membranes. This work is believed to shed useful insights on polyimicle membranes for pervaporation applications.

• 出版日期2015-12-15
• 单位华中科技大学