Gas permeation properties of asymmetric carbon hollow fiber membranes prepared from asymmetric polyimide hollow fiber

Asymmetric carbon hollow fiber membranes were prepared by pyrolysis of an a symmetric polyimide hollow fiber membrane, and their mechanical and permeat ion properties were investigated. The carbon membrane had higher elastic mo dulus and lower breaking elongation than the polyimide membrane. Permeation experiments were performed for single gases such as H-2, CO2, and CH4, and for mixed gases such as H-2/CH4 at high feed pressure ranging from 1 to 5 MPa with or without toluene vapor. The permeation properties of the carbon membranes and the polyimide membrane were compared. There was little change in the properties of the carbon membranes with a passage of time. The prop erties were hardly affected by the feed pressure, whether the feed was acco mpanied with the toluene vapor or not, because the carbon membranes were no t affected by compaction and plasticization. (C) 1999 Elsevier Science B.V. All rights reserved.