CO2分离用多功能基团掺杂混合基质膜材料的构建及增效机制

Mixed matrix membranes (MMMs) have great potential for CO2 capture from flue gas. Massive efforts have been devoted to investigating CO2 separation performance of the ether oxygen modified MMMs. In contrast, less attention is paid to those MMMs modified with ester. Our preliminary results demonstrate that some ester fillers can greatly improve CO2 separation performance of the MMMs, which is superior to ether oxygen fillers. However, the synergistic mechanism of ester fillers for CO2 permeation is still unclear, the stability of the MMMs is insufficient and the performance of the MMMs is constrained by a trade-off between the permeability and selectivity. In this proposal, considering of the aggregation structure of the polymer matrix, the MMMs will be constructed where thermoplastic polyester elastomer Arnitel will be used as matrix and branched fatty acid ester, ester functionalized MOFs and amino functionalized MOFs will be used as fillers respectively. A novel CO2 separation MMMs with excellent separation performance and good stability will be constructed in this study by adjusting the aggregation structure of the polymer matrix, optimizing the interface morphology between the matrix and filler and taking advantage of the synergistic effect of multiple CO2-affinity functional groups. Meanwhile, the interaction among polymer matrix, filler and CO2 as well as the change of MMMs micro-nanostructure, which can be controlled by adjusting the oxygen content in fatty acid ester, MOFs functional groups and the matching of the fillers, will be explored at molecular scale with the aid of instrumental characterization and molecular simulation analysis. The structure-activity relationship between the performance of the MMMs and the micro-nanostructure as well as the interaction among the components in the MMMs will be explored. Through this project, the synergistic mechanism of multifunctional group for improving the stability and the CO2 permeation performance of the MMMs including the breaking through of trade-off between the permeability and selectivity will be clear. This study will provide theoretical basis for the design and construction of high performance MMMs for CO2 separation.

混合基质膜(MMMs)是烟道气CO2捕集膜材料的重要发展方向。目前大量研究集中在醚氧类材料，而我们初步研究发现部分酯基材料性能远优于醚氧材料，但存在增效机制不清楚、稳定性不足和trade-off效应的问题。本项目以聚酯弹性体Arnitel为聚合物基质，以其聚集态结构为出发点，创造性地引入分枝状脂肪酸酯、酯基/氨基功能化MOFs，通过调节基质聚集态结构、优化界面形态，利用多功能基团协同作用,构建兼具优良分离性和良好稳定性的新型CO2分离膜材料。借助仪器表征和分子模拟，从分子尺度解析基质、填料和CO2相互作用关系及MMMs微纳结构变化。通过调节脂肪酸酯氧含量、MOFs功能基团及填料间的匹配，调控组分间相互作用及MMMs微纳结构，揭示其与MMMs性能之间的构效关系，阐释多功能基团协同增效MMMs分离性和稳定性、突破trade-off效应的途径和机制，为高性能CO2分离MMMs的设计提供理论依据。

混合基质膜（MMMs）是烟道气CO2捕集膜材料的重要发展方向。研究以富含酯基基团的甘油三酯为切入点，以热塑性弹性体为聚合物基质，基于分子三维立体空间结构对聚合物自由体积的影响，通过原位调控法制备Pebax/甘油三酯系列混合基质膜，阐释了甘油三酯结构变化对混合基质膜气体分离性能以及稳定性的影响。所制备的Pebax1657/TPP(50wt%)混合基质膜兼具优异的渗透分离性能和稳定性，CO2渗透系数可达1602Barrer，CO2/N2选择性30，并且可在65℃范围内保持热力学稳定。在此基础上，利用聚合物三维骨架结构固定液态TCP，制备了TCP含量高达80wt%的自支撑凝胶膜，明确了凝胶膜的化学结构及其相互作用与气体渗透分离性能和稳定性的关系。进一步地，通过功能化修饰MOFs材料的引入创建了多元凝胶混合基质膜（g-MMMs），在创建增强气体分离性能新通道的同时提高了膜材料的压力稳定性，通过FTIR、TGA、DSC、SEM等多种技术手段考察了g-MMMs分间相互作用以及微纳结构的变化，剖析了渗透系数变化的内在原因。所制备的凝胶混合基质膜CO2渗透系数可达1182Barrer，CO2/N2选择性23，突破了trade-off效应，并且具有良好的稳定性。项目研究结果揭示了混合基质膜微纳结构与其性能之间的构效关系，阐释多功能基团协同增效混合基质膜分离性和稳定性、突破trade-off效应的途径和机制，为高性能CO2分离混合基质膜的设计提供理论依据。