Preparation and Gas Permeation Properties of Composite Carbon Molecular Sieve Membranes Derived from Polyimides with Thermally Decomposable Sulfonic Acid Salt and/or Hexafluoroisopropylidene Group

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

Hidetoshi Kita¹  Kazuhiro Tanaka¹  Md. Nurul Islam¹  Ken-ichi Okamoto¹ 

[1] Department of Advanced Materials Science and Engineering, Yamaguchi University

关键词: Composite Membranes;    Carbon Molecular Sieve;    Sulfonated Polyimides;    Fluorinated Polyimides;    Gas Permeation;    Gas Separation;   

DOI  :  10.1252/jcej.39.131

来源: Maruzen Company Ltd

【 摘 要 】

References(14)Cited-By(6)Carbon molecular sieve (CMS) membranes were prepared from polyimides with sulfonic acid triethylammonium salt (SO3NH(C2H5)3) and/or hexafluoroisopropylidene (–C(CF3)2–) groups by pyrolyzing precursor composite membranes at the temperatures ranging from 773 to 973 K in an N2 flow for 1 h. The precursor membranes were prepared by coating the polyimides on ceramic porous support tubes. The sulfonic acid salt and the –C(CF3)2– group decomposed in the ranges of 573 to 673 K and 723 to 973 K, respectively. The composite CMS membranes prepared here had a defect-free top layer of 1.5 to 5 μm thick. The CMS membrane derived from the polyimide with both the thermally decomposable groups displayed the highest gas permeances. The decomposition of sulfonic acid groups followed by the decomposition of the –C(CF3)2– group just before the substantial decomposition of the polyimide backbone seemed to significantly enhance the micropore structure of the resultant pyrolytic layer. Compared to the CMS composite or hollow-fiber membranes reported in the literature, the membranes prepared in this study displayed higher O2 and CO2 gas permeances with reasonably high ideal separation factors for O2/N2 and CO2/N2 separations.

【 授权许可】

Unknown