Ester-Cross-linkableComposite Hollow Fiber Membranes for CO2Removal from NaturalGas.

High-performance ester-cross-linkablecomposite hollow fibers were developed through simultaneous spinningof 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)based polyimide and Torlon (registered trademark of Solvay Polymers)solutions. The core layer polyamide-imide polymer, Torlon, demonstratesexcellent adhesion with cross-linkable 6FDA-based polyimide duringspinning and ester-cross-linking. Torlon also shows superior thermalstability after cross-linking while maintaining the open substructureof the Torlon core layer. The resultant cross-linked composite hollowfibers show a CO2permeance of 40 GPU with a CO2/CH4selectivity of 39 in testing at 100 psi with 50/50CO2/CH4feed, 35 °C. The cross-linked compositehollow fibers also show high separation performance in the presenceof high-level toluene contaminants up to 1000 ppm, suggesting thatcross-linked composite hollow fibers are viable under realistic operationconditions. The high natural gas separation performance and significantlyreduced cost of hollow fiber formation provides a significant advancementin the state of the art for natural gas separations. [ABSTRACT FROM AUTHOR]