自具微孔嵌段高分子膜材料的可控合成与二氧化碳分离性能研究

High efficient CO2 separation membranes are greatly demanded from various fields including the clean energy and carbon dioxide reductions. However, it is still a big challenge to produce a polymer membrane with high permeability and good CO2 selectivity. Polymers of intrinsic microporosity (PIMs) are attractive membrane materials for gas separation due to their high specific surface and microporous structure. They show an extremely high CO2 permeability of up to 7140 barrer whereas a moderate selectivity that limits their industrial applications. In order to improve the CO2 selectivity of PIMs-based membranes, a new strategy is devolved to a novel PIMs-based membrane with high permeability and selectivity for CO2 separation. A series of novel PIM-b-PES block copolymers are synthesized from PIM-1 and poly(ether sulfone) (PES) oligomers by varying the block ratio and oligomers’ molecular weight. After that, polyethylene glycol (PEG) chains are grafted onto the PES chains of block copolymers and thus form a new polymer, that is PEG grafted PIM-b-PES block copolymers. The as-synthesized copolymers are used to prepare the dense membranes for CO2 separation. The membranes’ physic-chemical structure, microstructure, morphology and other properties are characterized in details. The microstructure of the membranes is controlled via adjusting the block ratio, the length of the oligomers (PIM-1, PES and PEG) to study the microstructure-property relationship of the membranes. The symbiosis among those influence factors and the dependence of composition-microstructure-property of the membranes are thus established. The mechanism of micro-phase segregation structure formation is studied to create a desirable micro-phase segregation structure and construct the highly permeable PIM-1 phase and PEG-g-PES phase with good CO2 selectivity. Thus, the as-formed membranes should have high permeability and selectivity for CO2 separation, will hold a great potential for a wide range applications in reduction of carbon dioxide emissions.

面向能源气体净化及温室气体减排的巨大需求，针对高CO2选择性自具微孔高分子（PIMs）膜材料的制备难题，从调控膜微观结构和引入功能基团着眼，提出高渗透性和高选择性的PIMs嵌段高分子膜材料的科学原理，开展CO2分离用高分子膜材料的合成和性能研究。以自具微孔高分子PIM-1为刚性链段、易化学改性的聚醚砜（PES）为柔性链段合成PIM-b-PES嵌段高分子，接枝聚乙二醇（PEG）以制备高性能CO2分离膜。利用嵌段高分子的自组装行为，形成高渗透性的PIM-1相和高CO2选择性的PES相组成的微相分离膜，实现CO2的快速、高效分离。研究微相分离结构的形成与调控机制，创建适宜的微相分离结构。实验与分子模拟相结合研究膜的组成-微观结构-性能三者之间的内在联系、气体分子的传质行为及分离机理，并建立传质模型，有望为PIMs气体分离膜材料的开发提供新的途径和理论依据，具有潜在的实用价值和重要的科学意义。

面向环境和能源领域对CO2分离的重大需求，针对高性能CO2分离膜的缺乏、高CO2选择性PIMs基高分子膜的制备难题，项目在前期研究工作基础上，从调控膜微观结构和引入功能基团着眼，提出了引入柔性易功能化链段以构建结构易控、性能易调的新型高性能微孔高分子膜材料的合成策略；合成了PIM-PES嵌段微孔高分子，获得了其合成方法、功能化技术及制膜工艺，揭示了调控膜微观结构的影响规律及化学结构与微观结构间的本质关系。项目还获得了PIM-1最优的合成工艺和制膜条件，开发了PIM-1/GO混合基质膜和酸催化自交联PIM-1膜。前者兼具高CO2选择性和高CO2渗透性，其性能超过Robeson上限；后者提高了抗塑化性同时也提高了CO2选择性。此外，受启发于PIM-1的刚性结构主链可以有效限制膜的溶胀同时微孔结构可以作为离子传输通道，提出了调控高分子链接距以构建高效离子通道的设计新思路，揭示了疏水交联剂长度与刚性、疏水性侧链的长度对阴离子交换膜结构和性能的影响规律，可用于指导高性能离子交换膜的开发。研究结果获国家授权发明专利2项，在Journal of Membrane Science（4篇）、Journal of Materials Chemistry A（3篇）、Chemical Engineering Journal、AIChE Journal、Chemical Engineering Science学术期刊上发表SCI收录论文14篇，其中JCR一区论文9篇、二区论文5篇。