Crosslinked and crosslinkable hollow fiber membrane and method of making same utility
AssigneeChevron U.S.A. Inc.
InventorsWilliam J. Koros, David Wallace, John Wind, Stephen J. Miller, Claudia Staudt-Bickel
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Abstract
A composition of and a method of making high performance hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer comprising covalently bonded ester crosslinks. The resultant hollow fiber membrane exhibits a high permeability of CO2 in combination with a high CO2/CH4 selectivity. Another embodiment provides a method of making the hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.
Claims19
A composite polymer membrane, comprising:
- a crosslinked polyimide polymer having covalent ester crosslinks;
- and having a CO2 permeance of at least 20 GPU and a CO2/CH4 selectivity of greater than 20, at 35 degrees C. and a pressure of 100 psia.
A composite polymer membrane, comprising:
- a crosslinked polyimide polymer having at least some covalent ester crosslinks and having a ratio of crosslinkable sites to imide groups of between 3:8 and 1:16.
A composite polymer membrane, comprising:
- a polyimide polymer made from the monomers A+B+C;
- where A is a dianhydride of the formula;
- where X1 and X2 are the same or different halogenated alkyl group, phenyl or halogen;
- where R1, R2, R3, R4, R5, and R6 are H, alkyl, or halogen;
- where B is a diamino cyclic compound without a carboxylic acid functionality;
- where C is a diamino cyclic compound with a carboxylic acid functionality;
- and
- wherein the ratio of B to C is between 1:4 and 8:1, and wherein said composite polymer membrane further comprises at least some covalent ester crosslinks.
Dependencies are inferred from the claim text.