基于ZIFs笼状结构对二氧化碳的可选择性高效捕获效应的PEO/ZIF杂化膜的设计与构筑

The capture of carbon dioxide is received considerable attention for environmental protection and energy shortage. Membranes separation technology with its inherent advantage, such as low energy consumption, has been a current research focus. The developments of membrane material and membrane with excellent performances are important keys. In this project, molecular simulation will be used in structure design and polymer synthesis. The novel star network poly (etheylene oxide) will be synthesized and used as organic matrix. The polyfunctional crosslinking agent will be used. The poly (etheylene oxide) with high CO2 permeability and high selectivity will be synthesized by free radical photopolymerization. The zeolitic imidazolate frameworks （ZIFs）with highly- efficient capture performance of CO2 will be introduced in polymer synthesis reaction to fabricate the PEO/ZIF mixed matrix membranes. The membranes will have high permeabilities and selectivities. The membranes will exhibit antiplasticization for high solubility selectivity, high adsorption selectivity and crosslink network structure. The reaction condition will be studied to ensure the optimal reaction conditions. The effect of mixed matrix membrane composition on membrane structure and performance will be studied. Comprehensive discussions will be presented about the design and fabrication of membrane material and membrane, the effects of material structure on CO2 permeability, selectivity and plasticization behavior. A controlled construction system of "Molecular simulation and structure design-Material synthesis-Membrane fabrication" for membrane will be established. The system will provide an effective way to develop excellent membrane material and membrane. The project will has important theoretical significance and applicable value.

环境及能源问题的日益突出使CO2捕集受诸多关注，膜分离因能耗低等优点成为当前研究热点，开发具有优异性能的膜材料及膜是关键。本项目利用分子模拟技术辅助有机基质星形网状聚氧乙烯（PEO）的结构设计及合成。采用多官能度交联剂，通过自由基光聚合，合成具有高CO2渗透性和溶解选择性的PEO为有机基质，在反应过程中引入可选择性地高效捕获CO2的沸石咪唑酯骨架材料（ZIFs），一步制备PEO/ZIF杂化膜，解决传统聚合物膜难以实现高渗透、高分离的难题；通过提高溶解及吸附选择性和构筑交联网状结构实现膜材料的有效抗塑化。考察反应条件对聚合物结构及性能的影响；考察杂化膜组成对膜结构和性能的影响。全面探讨膜材料及分离膜设计与制备、材料结构对渗透性、分离性和塑化行为的影响等问题，从而建立完善的"分子模拟与结构设计-膜材料合成-分离膜"的膜可控构筑体系，为膜材料及膜开发提供有效途径，具有重要的理论意义和应用价值。

在化工、能源和环境等相关领域中，从一些含有其他气体（例如：H2、CH4和N2等）的混合气中规模性分离CO2已经成为具有环保性和经济性的化工过程。膜法CO2分离由于其自身优势已成为当前的一个研究热点。研究开发具有良好CO2渗透性和良好CO2/light gases选择性的膜材料是提高膜分离技术竞争性的关键。. 首先以聚乙二醇甲醚丙烯酸酯（PEGMEA）为单体，分别以季戊四醇三丙烯酸酯、季戊四醇四丙烯酸酯、聚二季戊四醇五丙烯酸酯、聚二季戊四醇六丙烯酸酯及三羟甲基丙烷三丙烯酸酯为交联剂，通过自由基光聚合制备了多个系列的交联聚氧乙烯膜材料。考察了交联剂和交联剂含量对膜性能的影响，如膜的密度、玻璃化转变温度以及气体渗透和分离性能等。结果表明：与采用双官能团交联剂合成的聚合物相比，采用多官能团交联剂合成的多臂星形网状聚合物具有更高的气体渗透系数，多种聚合物的性能超越CO2/N2的罗宾逊上限。最高气体渗透渗透性能高达1300 Barrer（CO2，35℃，2 atm）。采用涂覆法制备的复合膜CO2渗透速率高达2060 GPU （CO2，35℃，2 atm）。利用合成的聚合物，制备了PEO/ZIF-8共混基质膜，结果表明：ZIF-8纳米粒子会填充到聚合物链段中，使链段间距变小，导致扩散系数下降；另一方面，纳米粒子的引入使得链段活动性降低，聚合物刚性变强，会导致溶解度系数的增大。为此，PEO/ZIF-8混合基质膜性能完全偏离了Maxwell模型，或出现正偏移，或出现负偏移。项目合成的多臂星形网状聚合物本身具有优异的气体渗透和分离性能，ZIF-8的引入并无益处，且制得的复合膜性能优异，在CO2分离领域非常有潜力。