| Efficient separation of low carbonlight olefin/paraffin is a key process for sustainable development of petrochemical industry.Gas membrane separation technology has the advantages of low energy consumption,and has become one of the most potential olefin/paraffin separation methods.However,currently,the commonly used polymer membrane materials have low selectivity for olefin,which cannot meet the requirements of industrialization currently.Therefore,membranes with high permeability flux and selective of olefin/paraffin separation membranes need to be developed.In this paper,Based on the development of glassy polymer polyimide Matrimid 5218（glassy polymer Matrimid 5218）composite membrane,rubbery polymer polyether copolyamideblock amide Pebax1657（rubbery polymer Pebax1657）composite membrane,and some polymer-ionic liquid blend membranes were prepared using dip-coating method.the structure and composition of blend membranes were characterized by FTIR、TGA、XPS、SEM and EDS.The permeation performance of propylene and paopane were also studied in detail.First of all,Pebax1657/PAN and Matrimid5218/PAN composite films were prepared with Pebax1657/PAN and Matrimid5218/PAN composite films by dip coating method.The influences of preparation conditions such as polymer concentration,coating thickness,solvent volatilization temperature and operating pressure and operating temperature on the properties of the composite films were investigated.Then,three silver-based ionic liquids,silver/1-hexene/trifluoromethanesulfonate[Ag（1-hexene）][NTf2],silver/N,N-Dimethylformamide/trifluoromethanesulfonate[Ag（DMBA）2][NTf2]and DES（silver trifluoromethanesulfonate/acetamide）,were synthesized,and their properties were characterized by FTIR TGA and other methodsIonic liquid-polymer composite membranes were prepared by blending Pebax1657with[Emim][NTf2]、[Ag（hexene）][NTf2]、[Ag（DMBA）2][NTf2]、DES（Ag CF3SO3:CH3CONH2）Compared with Pebax1657/PAN composite membranes containing conventional ionic liquids,the osmotic fluxes of C3H6 and C3H8 increased,and the separation coefficient of C3H6/C3H8 decreased.The blend composite membranes containing silver-based ionic liquids[Ag（hexene）][NTf2]/Pebax1657/PAN、[Ag（DMBA）2][NTf2]-pebax1657/PAN、DES-Pebax1657/PAN Compared with Pebax1657/PAN composite membrane,the permeability fluxes of C3H6 and C3H8 were decreased,and the separation coefficient of C3H6/C3H8 was increased.Among them,the separation coefficient of des-pebax1657/PAN composite membrane C3H6/C3H8 was the highest,and the influence of the addition of DES on the structure and performance of the blend membrane was further studied Results show that the interaction between DES and Peax1657,with the increase of content of DES,Pebax1657 crystallinity decreased,the amorphous structure increases,meanwhile blend membrane,C3H6 permeation flux and decreases,C3H6/C3H8 separation factor increases after the first decreases,and when DES content is 80%,mixed membranes separation factor of C3H6/C3H8 reached a maximum of5.94,compared with Pebax1657/PAN by about 100%... |
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