A series of hyperbranched copolyimides (co-HBPIs), as the completely symmetrical tetraamine monomer successfully incorporated into the linear polyimide 6FDA-ODA, were synthesized under the chemical imidization after the gel formation was avoided, as to more effectively separate CO₂/CH₄. CO₂/CH₄ selectivity (74%) was observed to be improved significantly under 7‰ tetraamine contents at 2 bar and 35°C; thus, the acceptable CO₂ permeability was maintained compared with the pure membrane, exceeding the 1991 upper bound. Moreover, the as-prepared membrane with 6FDA-ODA-7‰ was reported to exhibit higher CO₂/CH₄ selectivity (109.14) at 10 bar and 35°C. Accordingly, the hyperbranched copolyimides will be promising candidates as membrane materials for the further separation of CO₂/CH₄ gas pair.

避免凝胶形成后，在化学酰亚胺化作用下，合成了一系列成功引入线性聚酰亚胺6FDA-ODA中的完全对称的四胺单体-超支化共聚酰亚胺（co-HBPIs），以更有效地分离出CO ₂ / CH _4。。在2 bar和35°C下，四胺含量为7‰时，CO ₂ / CH ₄选择性（74％）得到了显着提高；因此，与纯膜相比，维持了可接受的CO ₂渗透率，超过了1991的上限。此外，据报道制备的具有6FDA-ODA-7‰的膜表现出更高的CO ₂ / CH _4。10 bar和35°C时的选择性（109.14）。因此，超支化共聚酰亚胺将有望用作进一步分离CO ₂ / CH ₄气体对的膜材料。