将4,4'-六氟亚异丙基-邻苯二甲酸酐(6FDA)和1,3-苯二胺(mPDA)与二端氨基聚醚缩聚,得到含有聚醚柔性链段的聚酰亚胺气体分离膜材料.所合成的共聚聚酰亚胺在N-甲基吡咯烷酮(NMP)和四氢呋喃(THF)等有机溶剂中具有良好的溶解性能.研究了O2,N2,H2,CH4和CO2在聚酰亚胺均质膜中的渗透性能,考察了二端氨基聚醚的含量、链长和化学结构对气体渗透性能的影响.结果表明,聚醚链段的引入增大了气体的扩散系数,气体的渗透系数显著增大;聚醚链段与CO2相对较强的相互作用,增大了对CO2/N2的溶解选择性,CO2/N2的分离性能优于CO2/CH4,同时CO2比H2优先透过膜.
Polyimide copolymers as materials for gas separation containing polyether soft segment were synthesized from 2,2-bis (3,4-dicarboxyphenyl) hexafluoroprophane dianhydride ( 6 FDA ) with m-phenylenediamine (mPDA) and polyether diamine by two steps of condensation polymerization. Permeation properties of O2, N2, H2, CH4 and CO2 were investigated. The co-polyimides were soluble in common solvents such as NMP and THF. The effects of content and structure of the polyether on permeation properties were studied. It was found that introducing soft polyether segment into polyimide main chain increased the diffusion coefficients due to in- creasing of chain flexibility, and also increased CO2 solubility selectivity due to the strong affinity of ether oxide groups with CO2. The results show that the permeability coefficients of CO2 for co-polyimides are higher than that for 6FDA-mPDA polyimide ; the CO2/N2 selectivity is better than CO2/CH4 ; meanwhile, CO2 permeability coefficients for co-polyimides is higher than H2.