An approach to predict the gas permeability of membrane polymers after supercritical CO 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 CO 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 CO modification while for polysulphone, the effective volume of mobile holes increased, but the nitrogen permeability decreased. For polycarbonate after supercritical CO, the effective volume of mobile holes and the nitrogen permeability increased.

中文翻译：

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超临界二氧化碳改性多孔膜聚合物的渗透性


提出了一种预测超临界 CO 处理后膜聚合物透气性的方法。该方法基于二次弛豫转变的温度与聚合物中移动自由体积单元的有效尺寸的联系。建立了一组聚合物的氮气渗透性和移动孔的有效尺寸之间的相关性。通过聚合物中引入的低分子量构象非均质化合物的 FTIR 光谱分析了超临界 CO 对聚碳酸酯、聚砜、聚乙烯醇缩丁醛氮渗透性的影响。膜分别经过静态处理和动态处理在40 MPa和333 K下暴露4 h。对于聚乙烯醇缩丁醛，超临界CO改性后氮渗透率没有变化，而对于聚砜，有效移动孔体积增加，但氮渗透率下降。对于超临界CO后的聚碳酸酯，移动孔的有效体积和氮渗透率增加。