Influence of Polymer Topology on Gas Separation Membrane Performance of the Polymer of Intrinsic Microporosity PIM-Py
Influence of Polymer Topology on Gas Separation Membrane Performance of the Polymer of Intrinsic Microporosity PIM-Py
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DOI：
10.1021/acsapm.1c00415
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发表时间：
2021-06-16
影响因子：
5
通讯作者：
Budd, Peter M.
中科院分区：
文献类型：
--
作者：
Devarajan, Anirudh;Asuquo, Edidiong D.;Budd, Peter M.
在不同的溶剂(二甲基甲酰胺和二甲基乙酰胺/二氯苯)和温度(65-160℃)下，研究了2，3，5，6-tetrafluoro-4-pyridinecarbonitrile-3，3，3‘，3’-tetramethyl-1，1‘-spirobisindane-5，5’，6，6‘-tetrol共聚物的聚合物合成，得到了一系列不同拓扑结构的聚合物样品。聚合物的表征，特别是质子核磁共振谱和多检测器SEC分析表明，与PIM-1一样，聚合过程进行了一定程度的聚合物链支化。这是由于发生了单取代反应，而不是双取代反应，最终导致了相当大比例的胶体网络的形成。然而，所有聚合物样品在氯仿中保持可溶/可分散，浓度达到浇铸独立薄膜所需的浓度。这项工作首次研究了PIM-Py作为气体分离膜的应用。结构最多样化的PIM-Py样品在单次气体渗透研究中表现出选择性/渗透性平衡，超过了2008年CO2/N-2气体对的罗伯逊上限。事实上，来自最高胶体网络含量样本的电影演员超过了最近引入的2019年CO2/N-2上限。经过143天的老化，40微米的自立膜仍然表现出4480巴的单气体CO2渗透率和45的理想CO2/N-2选择性。在DMF中的低温反应中产生的聚合物表现出与结构规则的“正常”PIM-1聚合物非常相似的气体分离性能，位于2008年Robeson上限线或附近。用于确定CO2/CH4选择性的单次气体渗透测量在整个聚合物样品范围内显示出类似的趋势，但通常没有达到像CO2/N-2对那样的高选择性。PIM-Py膜的混合气体CO2/CH4渗透随老化时间的变化也被测量，这表明了与结构规则的PIM-1聚合物相似的气体分离性能。这项研究表明，与PIM-1一样，PIM-Py的气体分离性能也受到聚合物样品中支化和网状材料的拓扑平衡的很大影响。
The polymer synthesis of 2,3,5,6-tetrafluoro-4-pyridinecarbonitrile-3,3,3',3'-tetramethyl-1,1'-spirobisindane-5,5',6,6'-tetrol copolymer, termed PIM-Py, was investigated under different solvent (dimethylformamide (DMF) and dimethylacetamide/dichlorobenzene) and temperature (65-160 degrees C) conditions to produce a range of topologically different polymer samples. Characterization of the polymers, particularly with proton NMR spectroscopy and multiple detector SEC analysis, indicated that, like PIM-1, the polymerizations proceeded with a degree of polymer chain branching. This is attributed to the occurrence of monosubstitution reactions, instead of disubstitution, which eventually leads to a significant proportion of colloidal network formation. However, all polymer samples remained soluble/dispersible in chloroform at the concentration required to cast self-standing films. This work reports the first examination of PIM-Py as a membrane for gas separation applications. The most structurally diverse PIM-Py samples produced films that exhibited selectivity/permeability balances in single gas permeation studies above the 2008 Robeson upper bound for the CO2/N-2 gas pair. Indeed, a film cast from the highest colloidal network content sample surpassed the recently introduced 2019 CO2/N-2 upper bound. After 143 days of aging, a 40 mu m self-standing membrane still exhibited a single gas CO2 permeability of 4480 barrer and an ideal CO2/N-2 selectivity of 45. The polymers produced in lower temperature reactions in DMF exhibited gas separation performances very similar to a structurally regular "normal" PIM-1 polymer, sitting on or around the 2008 Robeson upper bound line. Single gas permeation measurements to determine CO2/CH4 selectivity showed similar trends across the range of polymer samples, without generally reaching high selectivities as for the CO2/N-2 pair. Mixed gas CO2/CH4 permeation measurements with aging were also completed for PIM-Py membranes, which indicated similar gas separation performance to a structurally regular PIM-1 polymer. This study would suggest that, like PIM-1, gas separation performance of PIM-Py is greatly influenced by the topological balance toward branched and network material within the polymer sample.