The Synthesis,Modification And Gas Separation Properties Of 6FAP Polyimide

The relationship between the molecular structure and gas of the polybramidine membrane through the performance is the basis for achieving its separation of Robeson’s launch,and it is also a focus point of solving the problem of poor stability and high problems that can be separated on excessive specificity.The dissertation revolves around 2,2-dual（3-amino-4-hydroxylphenyl）hexfluoropropane（6FAP）.The separation of gas separation film,stability,and mechanical strength,and summarizes the relationship between the side chain and different gas through the nature of the side chain.The main work of the paper is divided into three parts:（1）The 6FAP-6FDA is prepared with 6FAP and 4,4-（hexarinopylopylopylene）dietic anhydride（6FDA）as the raw material,and then the a-6FAP-6FDA is prepared through the treatment of the acid anhydrial and ethidine.And c-6FAP-6FDA.The a-6FAP-6FDA membrane shows the best gas separation performance:the permeability of N₂,O₂,and CO₂ are 15.18±2.86 Barrer,44.28±4.89 Barrer,and 174.25±12.69 Barrer,O₂/N₂ and CO₂/N₂ ideal gas selectivity is 2.92±0.95 and 11.48±1.58.Compared with acetylization,the oligoma 6FAP-6FDA has the maximum average molecular chain spacing,the highest penetration of N₂,O₂,and CO₂,but O₂/N₂ and CO₂/N₂ selectively decrease.Results showed that the ester-based official energy group can efficiently adjust the gas separation performance.（2）Flexible dihamine monomer 2,2-dual（4,4-aminophenoxyl）propine（BAPP）,which is introduced to the 6FDA-6FAP main chain to increase the main chain polymerization.The a-6FDA-BAPP/6FAP and c-6FDA-BAPP/6FAP are prepared through the acid anhydrial and aceticide.The penetration of a-6FDA-BAPP/6FAP membrane has increased the penetration of N₂,O₂,and CO₂ to 31.36±2.09 Barrer,121.25±10.99 Barrer,and 1279.41±6.93 Barrer,O₂/N₂ and CO₂/N₂can reach 3.87±0.31and 40.80±2.27,and the amount of Yang’s modulus is 2389.00 MPa.Results showed that the introduction of the mechanical strength and gas separation performance of flexible ether bonding dual ammonia BAPP and acetate base fixing co-optimized membrane.（3）In this part,we optimize the 6FDA/BPADA-6FAP cross-linking asymmetric membrane of the 6FDA ratio and cross-linking time of BPADA.The results showed that when BPADA:6FDA=5:1,the main chain had the maximum polymerization,with average molecular weight of 98500 g mol^-1.After cross-linking 100 s,phase transfer 6FDA₁/BPADA₅-6FAP-MA membrane gas separation performance is the best.The penetration of N₂,O₂,and CO₂ of the membrane is 23.53±3.33 Barrer,155.50±9.64Barrer,and 638.53±52.29 Barrer;the selectivity of O₂/N₂ and CO₂/N₂ is 6.09±0.42 and25.01±2.21,respectively,and O₂/N₂separation performance far exceeds Robeson upper limit（2008）.