Gas sorption and diffusion in perfluoro(butenyl vinyl ether) based perfluoropolymeric membranes
Gas sorption and diffusion in perfluoro(butenyl vinyl ether) based perfluoropolymeric membranes
复制标题
全氟（丁烯基乙烯基醚）基全氟聚合物膜中的气体吸附和扩散
DOI：
10.1016/j.memsci.2021.120095
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发表时间：
2021
影响因子：
9.5
通讯作者：
S. Kentish
中科院分区：
文献类型：
--
作者：
Moataz Ali El;Liang Liu;M. H. Abdellah;E. Goudeli;S. Kentish
无定形玻璃态全氟聚合物的特征在于高的自由体积分数和疏烃性，这意味着它们在几种气体对的上限下表现。在这项研究中，一系列纯气体在Cytop®和全氟（丁烯基乙烯基醚）（PBVE）和全氟（2，2-二甲基-1，3-间二氧杂环戊烯）（PDD）的CyclAFlorTM无规共聚物中的吸附首次在不同温度下进行了研究。在根据聚合物体积行为的文献数据确定Sanchez-Lacombe模型参数之后，使用非平衡晶格流体（NELF）模型来模拟Cytop®中的吸附等温线。双模式吸附模型用于模拟聚（50%PBVE-共-50%PDD）中的吸附等温线。这些结果和先前公布的渗透率数据，然后使用内的传输模型，以确定扩散的扩散系数和活化能的范围内的气体在这些聚合物。CyclAFlor™共聚物显示出比Cytop®具有更高的CO2扩散率，同时保持相当的CO2/CH 4扩散率选择性。进行分子动力学（MD）模拟作为比较，以计算35 °C下的菲克扩散系数。从MD得到的扩散系数是一致的，由传输模型计算的He和H2，但偏离较大的渗透剂（即CO2和CH 4）。结果证实了CyclAFlor™共聚物在气体分离应用中的上级性能，其CO2溶解度和扩散率高于可比聚合物。
Amorphous glassy perfluoropolymers are characterized by high fractional free volume and hydrocarbon phobicity which means that they perform at the upper bound for several gas pairs. In this study, the sorption of a range of pure gases in Cytop® and a CyclAFlorTMrandom copolymer of perfluoro(butenyl vinyl ether) (PBVE) and perfluoro(2,2-dimethyl-1,3-dioxole) (PDD) are studied for the first time at different temperatures. The Non-Equilibrium Lattice Fluid (NELF) model is used to model the sorption isotherms in Cytop®, after the determination of the Sanchez-Lacombe model parameters from literature data of the polymer volumetric behavior. The Dual Mode Sorption model is used to model the sorption isotherms in Poly(50%PBVE-co-50%PDD). These results and previously published permeability data are then used within a transport model to determine the diffusivity and activation energy of diffusion for a range of gases within these polymers. The CyclAFlor™ copolymer is shown to have a higher CO2diffusivity than Cytop®, while maintaining comparable CO2/CH4diffusivity selectivity. Molecular Dynamics (MD) simulations are performed as a comparison, to calculate the Fickian diffusion coefficients at 35 °C. The diffusion coefficients obtained from MD are consistent with those calculated by the transport model for He and H2but deviate for larger penetrants (i.e. CO2and CH4). The results confirm the superior performance of the CyclAFlor™ copolymer for gas separation applications, with greater CO2solubility and diffusivity than comparable polymers.