Abstract:

As an emerging technology, membrane-based gas separation has received widespread attention. Aromatic polyimide is one of the most promising materials for gas separation membranes. Currently, polyimide with various structures has been developed and researched on laboratory scales. However, in situations of industrial application, the physical aging phenomenon of membrane materials during long-term operation significantly affects the accurate evaluation of gas separation performance and the reasonable design of process parameters. The current research status of the physical aging behavior of polyimide thin films and asymmetric membranes was reviewed, the aging mechanism and models proposed by predecessors were summarized, the main factors affecting the aging process were analyzed and the prevention methods of physical aging were proposed. The characteristics of polyimide used for gas separation membranes that were not prone to aging included high molecular chain rigidity, limited chain space configuration, and appropriate inter-chain interactions. Future research was expected to focus on not only developing new structures of polyimides as well as crosslinking agents, but also preparation process optimization.

Key words: polyimide, gas, separation, membranes, physical aging, free volume, model

摘要：

气体分离膜技术是一项广受关注的新兴技术，芳香族聚酰亚胺是最具应用前景的气体分离膜材料之一。目前，学术界已对多种结构的聚酰亚胺进行了实验室规模的开发和研究，但在实际工业应用情境下，膜材料长期服役过程中的物理老化现象极大影响着气体分离性能的准确评估和工艺参数的合理设计。本文综述了当前针对聚酰亚胺类薄膜和非对称膜物理老化行为的研究现状，总结了前人提出的老化机理模型，分析了影响老化进程的主要因素，提出了物理老化的预防和改善方法。提出不易老化的气体分离膜用聚酰亚胺应具备的特质包括较强的分子链刚性、受限的链空间构型和合适的链间相互作用。未来相关研究的重点方向可能为聚酰亚胺新结构探索、交联剂开发、制备工艺优化等方面。

关键词: 聚酰亚胺, 气体, 分离, 膜, 物理老化, 自由体积, 模型