Abstract Polyimide has been widely investigated as a potential material for gas separation. The post-crosslinking of polyimide could increase gas selectivity and membrane stability due to increase of chain-packing density and chain stiffness. However, common crosslinking strategies tend to destroy the chemical structure of polyimide. In this work, a strong hydrogen bond among polymer chains of 6FDA-durene polyimide (Du-PI) membranes is designed by introducing isophthalic dihydrazide (IPD) molecules as cross-linker. The formation of hydrogen bond between Du-PI and IPD strengthens the polymer interchain interaction and regulates interchain spacing but without breaking the chemical structure of Du-PI. The resulting IPD/Du-PI membranes exhibit largely enhanced mechanical strength and anti-plasticization property in comparison with pristine Du-PI membranes. In addition, due to the increased packing density of polymer chains, the membranes show obviously increased gas perm-selectivity by 296%, 505%, 125%, 66%, and 171% for H2/N2, H2/CH4, H2/CO2, O2/N2, and CO2/CH4 gas pair in the case of 20% IPD/Du-PI membrane. The use of IPD as cross-linker has demonstrated herein to be a facile and effective strategy to strengthen the inter-polymer chain interaction and simultaneously improve membrane stability in a mild way.

中文翻译：

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设计聚酰亚胺膜中的链间氢键以提高气体选择性和膜稳定性

摘要 聚酰亚胺作为一种潜在的气体分离材料已被广泛研究。由于链堆积密度和链刚度的增加，聚酰亚胺的后交联可以提高气体选择性和膜稳定性。然而，常见的交联策略往往会破坏聚酰亚胺的化学结构。在这项工作中，通过引入间苯二甲酸二酰肼 (IPD) 分子作为交联剂，设计了 6FDA-杜烯聚酰亚胺 (Du-PI) 膜聚合物链之间的强氢键。Du-PI与IPD之间形成氢键加强了聚合物链间相互作用并调节链间间距，但不破坏Du-PI的化学结构。与原始的 Du-PI 膜相比，所得 IPD/Du-PI 膜的机械强度和抗塑化性能大大增强。此外，由于聚合物链的堆积密度增加，膜对 H2/N2、H2/CH4、H2/CO2 的气体渗透选择性明显提高了 296%、505%、125%、66% 和 171%在 20% IPD/Du-PI 膜的情况下，O2/N2 和 CO2/CH4 气体对。使用 IPD 作为交联剂在本文中已证明是一种简便有效的策略，可以增强聚合物间链的相互作用，同时以温和的方式提高膜稳定性。和 CO2/CH4 气体对在 20% IPD/Du-PI 膜的情况下。使用 IPD 作为交联剂在本文中已证明是一种简便有效的策略，可以增强聚合物间链的相互作用，同时以温和的方式提高膜稳定性。和 CO2/CH4 气体对在 20% IPD/Du-PI 膜的情况下。使用 IPD 作为交联剂在本文中已证明是一种简便有效的策略，可以增强聚合物间链的相互作用，同时以温和的方式提高膜稳定性。