Preparation And Properties Of Polyimide Thermo-crosslinked Membrane Gas Separation Materials Containing Phenylacetylene

Along with the increasingly prominent environmental and energy issues,To seek a kind of environmentally friendly and energy saving materials is one of the problems at this stage we need to be addressed.Gas separation membrane materials to become one of the effective solutions to the problem of the new technology.Gas separation membrane is a kind of membrane separation material which is mainly used in the separation of air,adsorption of carbon dioxide,separation and recovery of hydrogen in the exhaust of petrochemical plant.Due to its advantages such as high efficiency,low energy,low cost and environmental friendliness,it has aroused more and more in-depth exploration of researchers.For gas separation membrane,the contradiction of present main research is how to decrease gas permeability and selectivity of the trade-off between conditionality,as well as how to improve the thermal stability of gas separation membrane and the plasticizing capability.In the first part of the experiment,we introduce a alkynyl containing benzene dianhydride monomer 4ETA?4,4'?acetylene-1,2-2?2?phthalic anhydride,and 6?4,4'-?second from six different propylene?phthalic anhydride?to another dianhydride monomer,DAM and diamine monomer?2,6 minus-trimethyl-1,3-phenylenediamine?ternary copolymerization,synthesis of a series of main chain containing benzene alkynyl can be cross-linked polyimide copolymer,and through the thermal crosslinking methods,the preparation of a series of main chain type thermal cross-linking polyimide polymer,to the study of modification.After thermal crosslinking of polyimide and reduce the internal activity and close packing of molecular chain,to improve the gas permeability,internal crosslinking structure can provide selective channel,so the selectivity can also be guaranteed,through testing,we found that this series of polymers,the cross-linked before until after crosslinking,the CO₂ permeability increase,crosslinking before 4ETA-PI5%CO₂ permeability is 1016.7 barrer,increased to1221.9 barrer after crosslinking,and selective not significantly reduced,at the same time improve the thermal stability,by former crosslinking T_d5%to 532?to 563?,is accomplished by means of a thermal crosslinking of polyimide functionalization modification.In the second part of the experiment,we synthesized a kind of side chain first dianhydride monomer containing benzene alkynyl-PEPHQDA?4,4'?phenylacetylene phenyl of benzene?ether dianhydride?,in the same way,with 6FDA for another dianhydride monomer,DAM as the diamine monomer,ternary copolymerization.A series of crosslinked polyimide copolymers containing phenylenyl groups were synthesized and a series of crosslinked thermo-crosslinked polyimide polymers were prepared.Through the test,we found that this series of polymers,after the crosslinking before the crosslinking,increased the permeability of CO₂,and the CO₂ permeability of PEPHQDA-PI5%was 771.4 barrer,which was increased to 995.3 barrer after crosslinking.At the same time,the thermal stability was improved,and the T_d5%of the crosslinking was increased to 570?by 545?,which resulted in the modification of polyimide functionalization by means of heat crosslinking.In conclusion,this thesis designed and synthesized two containing benzene alkynyl structure can be crosslinked polyimide copolymer-main chain and side chain,in order to improve the gas transport resistance and thermal stability,we respectively on the thermal crosslinking treatment,after cross-linking polyimide because of the reticular structure,forming limit freedom of movement of the chain,reduced the close packing of chain segment,thereby increasing the free volume,and makes the permeability increased significantly,and the selective no obvious drop,at the same time compared with before the crosslinking,thermal stability,proved by thermal crosslinking methods for functional polyimide polymer containing benzene alkynyl processing have broad application prospects in the field of gas separation membrane.