Four high-rigidity poly(oxo-biphenylene-isatin) polymers (POBIs)─poly(2-oxo-3-biphenyleneindole) (POBI-H), poly(2-oxo-3-biphenylene-1-(4-fluorophenyl)indole) (POBI-FPh), poly(2-oxo-3-biphenylene-1-(3-trifluoromethylphenyl)indole) (POBI-TFMPh), and poly(2-oxo-3-biphenylene-1-(3,5-bis(trifluoromethyl)phenyl)indole) (POBI-bTFMPh)─bearing a systematic increase in bulky lateral phenyl-fluorine groups were synthesized by a superacid catalyzed reaction. Thin-film membranes from POBIs were prepared by solution casting and pyrolyzed under an inert atmosphere (Ar) to obtain carbon molecular sieve membranes (CMSMs) at 600 °C. During the pyrolysis processes, −CF₃ decomposition produces an amorphous carbon structure with more open strands, as found from an increase between carbon strand distances, L_a and L_c, and pore volume. A comparison of POBI precursor films and CMSM gas transport properties shows that CMSM presents a 10-fold increase in permeability over POBI precursors. A high gas permeability was observed, ascribed to an improved gas sorption capability in the CMSM due to an increase in condensability and surface area between POBIs as the bulkiness of phenyl-fluorine substitution increases. Aging of CMSM POBI membranes shows a decrease in permeability compared to the initial CMSM, which is larger for pyrolyzed POBI-bTFMPh, due to the rearrangement of the amorphous turbostratic structure and a considerable increase in ideal selectivity associated with the formation of compact micropores by the rearrangements of the carbon strand with an increase in ultramicropores. The overall effect of the systematic increase in bulkiness of phenyl-fluorene substitution in the POBI precursor to obtain CMSM is an increase in P due to a higher gas sorption S resulting from an increase in the pore volume and surface area and a larger L_c and L_a among the carbonaceous strands.

中文翻译：

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由聚（氧代-联苯-谴氨酸）制成的碳分子筛膜具有越来越大的氟取代物：表征和气体传输特性


四种高刚性聚（氧代-联苯-亚胺-菩萨基）聚合物（POBI）─聚（2-氧代-3-联苯-1-（3-联苯）吲哚：，（POBI-H）、聚（2-氧代-3-联苯-1-（4-氟苯基）吲哚）（POBI-FPh）、聚（2-氧代-3-联苯-1-（3-三氟甲基）苯基）吲哚：：：（POBI-TFMPh）和聚（2-氧代-3-联苯-1-（3,5-双（三氟甲基）苯基）吲哚）（POBI-bTFMPh））─ 通过超强酸催化反应合成了系统性增加的块状侧苯基-氟基团。通过溶液浇注制备 POBIs 薄膜，并在惰性气氛 （Ar） 下热解，在 600 °C 下获得碳分子筛膜 （CMSM）。 在热解过程中，−CF₃ 分解产生具有更多开放链的无定形碳结构，这从碳链距离、L_a 和 L_c 与孔体积之间的增加中可以看出。POBI 前驱体膜和 CMSM 气体传输特性的比较表明，CMSM 的渗透性比 POBI 前驱体高 10 倍。观察到高透气性，这归因于 CMSM 中气体吸附能力的提高，因为随着苯氟取代体积的增加，POBI 之间的冷凝性和表面积增加。与初始 CMSM 相比，CMSM POBI 膜的老化显示通透性降低，初始 CMSM 对于热解的 POBI-bTFMPh 更大，这是由于无定形涡状结构的重排和理想选择性的显着增加，与碳链的重排和超微孔的增加有关。 为获得 CMSM 而获得的 POBI 前驱体中苯基-芴取代的体积系统增加的总体效果是 P 的增加，这是由于孔体积和表面积的增加导致更高的气体吸附 S 以及碳质链中更大的 L_c 和 L_a。