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Relationships between chemical structures and solubility, diffusivity, and permselectivity of 1,3-butadiene andn-butane in 6FDA-based polyimides

Authors :
Masatoshi Maeda
Akira Shimazu
Tomoko Matsushita
Tsukasa Miyazaki
Kenichi Ikeda
Source :
Journal of Polymer Science Part B: Polymer Physics. 37:2941-2949
Publication Year :
1999
Publisher :
Wiley, 1999.

Abstract

The solubility, diffusivity, and permselectivity of 1,3-butadiene and n-butane in seven different polyimides synthesized from 2,2-bis (3,4-carboxyphenyl) hexafluoropropane dianhydride (6FDA) were determined at 298 K. The influence of chemical structures on physical and gas permeation properties of 6FDA-based polyimides was studied. Solubility of 1,3-butadiene in 6FDA-based polyimides can be described by a dual-mode sorption model. 1,3-Butadiene-induced plasticization is considered to be associated with the increasing permeabilities of 1,3-butadiene and n-butane and the decreasing permselectivity of 1,3-butadiene vs. n-butane in the mixed gas system containing a high concentration of 1,3-butadiene. It was found that controlling the solubility of 1,3-butadiene in an unrelaxed volume in 6FDA-based polyimides is very important to maintain the high permselectivity of 1,3-butadiene vs. n-butane in the mixed gas system. Changing the-C(CF 3 ) 2 - linkage to a -CH 2 -, -O- linkage, removing methyl substituents at the ortho position of the imide linkage, and changing the p-phenylene linkage to an m-phenylene linkage in the main chains in some 6FDA-based polyimides are effective to decrease fractional free volume and restrict the solubility of 1,3-butadiene in the unrelaxed volume of a polymer matrix. The 6FDA-based polyimides restricting the solubility of 1,3-butadiene in an unrelaxed volume exhibit high separation performance in the 1,3-butadiene/n-butane mixed gas system compared with conventional glassy polymers and, therefore, are potentially useful membrane materials for the separation of 1,3-butadiene and n-butane in the petrochemical industry.

Details

ISSN :
10990488 and 08876266
Volume :
37
Database :
OpenAIRE
Journal :
Journal of Polymer Science Part B: Polymer Physics
Accession number :
edsair.doi...........eb7c856a50b8f9383617e4ead257fb5e
Full Text :
https://doi.org/10.1002/(sici)1099-0488(19991101)37:21<2941::aid-polb4>3.0.co;2-5