Permeability of porous membrane polymers modified by supercritical carbon dioxide

IF 3.4 3区工程技术 Q2 CHEMISTRY, PHYSICAL Journal of Supercritical Fluids Pub Date : 2024-07-20 DOI:10.1016/j.supflu.2024.106357

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Abstract

An approach to predict the gas permeability of membrane polymers after supercritical CO₂ treatment is proposed. The approach is based on the connection of the temperatures of secondary relaxation transitions with the effective sizes of mobile free volume elements in the polymers. The correlation between permeability of nitrogen and effective sizes of mobile holes for a set of polymers is established. The effect of supercritical CO₂ on the nitrogen permeability of polycarbonate, polysulfone, polyvinylbutyral is analyzed by FTIR spectroscopy of low-molecular weight conformationally-inhomogeneous compounds introduced in the polymers. Membranes were exposed at 40 MPa and 333 K for 4 h through static treatment and dynamic treatment separately. For polyvinylbutyral, the nitrogen permeability did not change after supercritical CO₂ modification while for polysulphone, the effective volume of mobile holes increased, but the nitrogen permeability decreased. For polycarbonate after supercritical CO₂, the effective volume of mobile holes and the nitrogen permeability increased.

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超临界二氧化碳改性多孔膜聚合物的渗透性

本文提出了一种预测膜聚合物经超临界 CO 处理后气体渗透性的方法。该方法基于二次弛豫转变温度与聚合物中可移动自由体积元素有效尺寸之间的联系。建立了一组聚合物的氮渗透性与移动孔有效尺寸之间的相关性。通过对聚合物中引入的低分子量构象均一化合物的傅立叶变换红外光谱分析了超临界 CO 对聚碳酸酯、聚砜和聚乙烯醇缩丁醛的氮渗透性的影响。分别通过静态处理和动态处理，将膜暴露在 40 兆帕和 333 K 的环境中 4 小时。对于聚乙烯醇缩丁醛，超临界 CO 改性后氮渗透性没有变化；而对于聚砜，移动孔的有效体积增加了，但氮渗透性降低了。聚碳酸酯经过超临界 CO 改性后，移动孔的有效体积和氮渗透率都有所增加。

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来源期刊

Journal of Supercritical Fluids 工程技术-工程：化工

CiteScore

7.60

自引率

10.30%

发文量

236

审稿时长

56 days

期刊介绍： The Journal of Supercritical Fluids is an international journal devoted to the fundamental and applied aspects of supercritical fluids and processes. Its aim is to provide a focused platform for academic and industrial researchers to report their findings and to have ready access to the advances in this rapidly growing field. Its coverage is multidisciplinary and includes both basic and applied topics. Thermodynamics and phase equilibria, reaction kinetics and rate processes, thermal and transport properties, and all topics related to processing such as separations (extraction, fractionation, purification, chromatography) nucleation and impregnation are within the scope. Accounts of specific engineering applications such as those encountered in food, fuel, natural products, minerals, pharmaceuticals and polymer industries are included. Topics related to high pressure equipment design, analytical techniques, sensors, and process control methodologies are also within the scope of the journal.