A series of thermal rearrangement (TR) copolymer membranes were developed through the copolymerization of 9,9-bis(3-amino-4-hydroxyphenoxyphenyl) fluorene (BAHPPF), 9,9-bis(3-amino-4-hydroxyphenyl)fluorene (BAHPF), and 2,2′-bis(3,4′-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), followed by thermal imidization and subsequent thermal rearrangement. The influence of the molar ratio of diamines on the structure and performance of these copolymer membranes was systematically investigated. Notably, the copolymer precursors CP-4:6 and CP-5:5 exhibited outstanding mechanical properties. While the mechanical strength of the precursor membranes declined rapidly with increasing thermal treatment temperature, TRCP-4:6 retained a tensile strength of 21.2 MPa after exposure to 450 °C. Generally, gas permeabilities of TR copolymers increased with higher BAHPF content.NR1I3 Antibody In stock Among the tested samples, TRCP-3:7 and TRCP-4:6 demonstrated superior gas permeability combined with high O₂/N₂ and CO₂/CH₄ selectivities.Transferrin Antibody Purity & Documentation Specifically, TRCP-4:6 achieved H₂, CO₂, O₂, N₂, and CH₄ permeabilities of 244.4, 269.0, 46.8, 5.20, and 4.60 Barrers, respectively, with CO₂/CH₄ and O₂/N₂ selectivities reaching 58.48 and 9.00—both exceeding the 2008 upper bound for gas separation performance. These results indicate that the fluorene-based TR copolymers are promising candidates for advanced membrane materials in gas separation applications.
The study highlights the potential of incorporating rigid fluorene units into thermally rearranged polymers to enhance both gas transport and mechanical integrity. The presence of bulky fluorene groups effectively disrupts chain packing, increases free volume, and improves molecular rigidity, which are critical factors in achieving high permeability without sacrificing selectivity. Moreover, the copolymerization strategy enables fine-tuning of the chemical architecture, allowing optimization of both physical and separation properties. The successful balance between enhanced permeability and maintained mechanical robustness underscores the feasibility of these materials for practical deployment in industrial gas separation processes such as CO₂ capture from natural gas streams or hydrogen purification.PMID:35230092 This work provides a clear pathway toward next-generation polymer membranes that overcome the traditional trade-off between permeability and selectivity, paving the way for more efficient and sustainable separation technologies.
The structural evolution during thermal rearrangement was confirmed via FTIR, XPS, and XRD analyses, showing the formation of benzoxazole rings and an increase in interchain spacing due to CO₂ release. The amorphous nature of the resulting membranes, coupled with a significant increase in d-spacing—reaching up to 0.60 nm in TRCP-4:6—supports the development of effective microporous networks favorable for selective gas diffusion. Additionally, DSC and DMA data revealed glass transition temperatures around 350 °C, indicating excellent thermal stability suitable for demanding operational environments. Overall, this research demonstrates that fluorene-containing TR copolymers offer a unique combination of high gas permeability, exceptional selectivity, and sufficient mechanical durability, making them strong contenders for future membrane-based gas separation systems.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com