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Indexed by:会议论文

Date of Publication:2015-01-01

Included Journals:CPCI-S、SCIE

Volume:39

Page Number:62-67

Key Words:Polyimide; Flourene; Gas separation properties; Solubility; Structure and properties

Abstract:The six kinds of polyimides(PIs) containing fluorene units were prepared from 9,9'-bis(4-aminophenyl)fluorene(BAF) with various dianhydrides including 2,2'-bis-(3,4-dicarboxyphenyl)hexafluoropropane dianhydride(6FDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA), 4,4'-oxydiphthalic anhydride(ODPA), 3,3', 4,4'-biphenyltetracarboxylic dianhydride(BTDA), pyromellitic dianhydride(PMDA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride(CBDA) via chemical imidization. Wide-angle X-ray diffractograms revealed that the polymers were amorphous. Most of the polyimides exhibited good solubility and could be readily dissolved in various solvents such as N-Methyl-2-pyrrolidone(NMP), N,N-dimethylacetamide(DMAc), N,N-dimethylformamide(DMF), and so on. The polyimide was thermally treated at 300 degrees C, 420 degrees C and 550 degrees C for further carbonization. Gas permeation properties for O-2 and N-2 of the PI-BPDA and PI-CBDA membranes were investigated. The permeability coefficients and selectivity for O-2 and N-2 of polyimide were obtained. With the increase of thermal treatment temperature, the permeability for O-2 and N-2 of polyimides increased, but the selectivity decreased. The gas separation mechanism for O-2 and N-2 was mainly molecular sieving.