Chemical cross-linking modification of polyimide membranes for gas separation
Chemical cross-linking modification of polyimide membranes for gas separation
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DOI：
10.1016/s0376-7388(01)00415-x
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发表时间：
2001-08-15
影响因子：
9.5
通讯作者：
Chung, TS
中科院分区：
文献类型：
--
作者：
Liu, Y;Wang, R;Chung, TS
我们开发了一种非常简单的室温化学交联技术，用于修饰用于He/N-2和O-2/N-2气体分离的聚酰亚胺薄膜。以6FDA-durene为例，将致密的6FDA-durene薄膜浸泡在对二甲二胺甲醇溶液中一段时间，然后用新鲜甲醇洗涤，在常温下干燥，进行化学改性。FTIR监测了交联过程中化学结构的变化，表明在改性过程中亚胺基转变为酰胺基。TGA分析表明，交联聚酰亚胺在气体分离应用中具有热稳定性。测定了改性聚酰亚胺在35℃和10 atm下对He、O-2、N-2和CO2的气体渗透性能。研究发现，随着交联程度的增加，气体渗透率以CO2 > N-2 > O-2 > He的顺序显著降低，这主要是由于扩散系数的显著降低。He/N-2和O-2/N-2的超选择性分别从10提高到86和4.1提高到5.9，而CO2/N-2的超选择性从12降低到5.4，表明这种交联方法对He/N-2和O-2/N-2的分离应用最有用。(C) 2001 Elsevier Science B.V.版权所有
We have developed an extremely simple room temperature chemical cross-linking technology for the modification of polyimide films for gas separations of He/N-2 and O-2/N-2. Using 6FDA-durene as an example, chemical modification is performed by immersing the dense 6FDA-durene films in a p-xylenediamine methanol solution for a certain period of time followed by washing with fresh methanol and drying at ambient temperature. The chemical structure changes during the cross-linking process were monitored by FTIR, which indicated that imide groups were turned to amide groups during the modification process. TGA analyses showed cross-linked polyimides were thermally stable for gas separation applications. Gas permeation properties of modified polyimides to He, O-2, N-2 and CO2 were measured at 35 degreesC and 10 atm. It is found that the gas permeability decreased significantly in the order of CO2 > N-2 > O-2 > He with an increase in the degree of cross-linking, which were mainly attributed to the significant decreases in diffusion coefficients. The permselectivities of He/N-2 and O-2/N-2 increased from 10 to 86 and from 4.1 to 5.9, respectively, but CO2/N-2 decreased from 12 to 5.4, which suggest this cross-linking approach is most useful for the application of He/N-2 and O-2/N-2 separations. (C) 2001 Elsevier Science B.V. All rights reserved.