聚酰亚胺中空纤维膜材料自由体积与氙渗透性能相关性研究  

Correlation of Xenon Permeability in Polyimide Hollow Fiber Membranes With Free Volume

作　　者：安少杭 陈占营[1] 刘蜀疆[1] 马梦瑶 盛毓强 常印忠[1] 李奇[1] 王世联[1] AN Shaohang;CHEN Zhanying;LIU Shujiang;MA Mengyao;SHENG Yuqiang;CHANG Yinzhong;LI Qi;WANG Shilian(CTBT Beijing National Data Center and Beijing Radionuclide Laboratory,Beijing 100085,China)

机构地区：[1]禁核试北京国家数据中心和北京放射性核素实验室,北京100084

出　　处：《现代应用物理》2024年第6期177-186,共10页Modern Applied Physics

基　　金：国家自然科学基金资助项目(12205126)。

摘　　要：针对氙富集浓缩需求,以3种聚酰亚胺PI-X,PI-E,PI-M为对象,研究了膜材料自由体积与气体渗透性能的关系。采用能谱分析、傅里叶红外光谱、核磁共振、X射线衍射等方法表征了聚酰亚胺的官能团和链段间距;通过正电子湮灭寿命测量技术,测定了3种聚酰亚胺的平均自由体积并计算了相对自由体积分数;测试了氧气、氮气、氙气在3种聚酰亚胺中的渗透速率,计算了理想气体分离系数;对平均自由体积、相对自由体积分数及气体渗透速率进行了Spearman相关性分析。结果表明,PI-X携带-SO_(2)-,-CF_(3),-Cl等官能团,链段间距(125.9 pm)和平均自由体积(0.381 nm^(3))均大于PI-E和PI-M的同类参数,说明大体积官能团的引入有利于增加聚酰亚胺的自由体积;PI-X的气体渗透性能(J_(O)=31.4,J_(N)=4.46,J_(Xe)=0.66)和氙气分离性能(α_(O/Xe)=47.58,α_(N/Xe)=6.76)均优于PI-M和PI-E;聚酰亚胺的气体渗透速率与平均自由体积的Spearman相关性为1,具有强正相关性,与相对自由体积分数相关性不强。Polyimide hollow fiber membranes are widely used in xenon separation.To meet the demand for xenon enrichment and concentration,the relationship between the free volume and gas permeation performance of membrane materials is investigated using three polyimides,PI-X,PI-E,and PI-M.The functional groups and chain segment spacing of the polyimides are characterized by energy spectrum analysis,Fourier infrared spectroscopy,nuclear magnetic resonance,and X-ray diffraction.The average free volumes and relative free volume fractions of the three polyimides are determined and calculated by the positron annihilation lifetime measurement technique.The permeation rates of oxygen,nitrogen,and xenon in the three polyimides are tested,and the ideal gas separation coefficients are calculated.The relationship among the average free volumes,relative free volume fractions,and gas permeation rate is investigated.Spearman's correlation analyses are carried out for the average free volume,relative free volume fraction,and gas permeation rate.The results show that PI-X carries functional groups such as-SO_(2)-,-CF_(3),and-Cl,and the chain segment spacing(125.9 pm),as well as average free volume(0.381 nm 3),are larger than those of the same parameters of PI-E and PI-M,indicating that the introduction of bulky functional groups is conducive to the increase of the free volume of the polyimide.The gas permeation performance of PI-X(J_(O)=31.4,J_(N)=4.46,J_(Xe)=0.66)and xenon separation performance(α_(O/Xe)=47.58,α_(N/Xe)=6.76)are better than those of PI-M and PI-E.The Spearman's correlation between the gas permeation rate and the average free volume is 1,which is a strong positive correlation,and the correlation with the relative free volume fractions is not significant.

关 键 词：聚酰亚胺 正电子湮灭寿命 自由体积 氙 气体渗透速率 

分 类 号：TB324[一般工业技术—材料科学与工程]