Membranes of glassy polymer blends with peg-crosslinked intrinsic microporous polymers for gas separations
This disclosure relates to blended polymeric membranes containing a polyimide polymeric matrix blended with a crosslinked polymer of intrinsic microporosity and methods of using the membranes for gas separation applications, such as removal of CO 2 from natural gas.
1. A blended polymeric membrane comprising:
a co-polyimide polymeric membrane matrix;
a polymer of intrinsic microporosity (PIM); and
a polyethylene glycol-bisazide (PEG-bisazide) crosslinking agent having an average molecular weight (Mn) of about 200 to about 40,000,
wherein the PIM is crosslinked with the PEG-bisazide crosslinking agent.
2. The blended polymeric membrane of claim 1 , wherein the co-polyimide polymeric membrane matrix comprises a 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA)-based polyimide.
3. The blended polymeric membrane of claim 2 , wherein the 6FDA-based polyimide has an average molecular weight (Mn) of about 150,000 to about 230,000.
4. The blended polymeric membrane of claim 2 , wherein the 6FDA-based polyimide is 6FDA-DAM: DABA.
5. The blended polymeric membrane of claim 4 , wherein the 6FDA-based polyimide is 6FDA-DAM: DABA (3:2).
6. The blended polymeric membrane of claim 1 , wherein the PIM is PIM-1.
7. The blended polymeric membrane of claim 1 , wherein the PIM has an average molecular weight (Mn) of about 70,000 to about 100,000.
8. The blended polymeric membrane of claim 1 , wherein the PEG-bisazide crosslinking agent has an average molecular weight (Mn) of about 600 to about 2,000.
9. The blended polymeric membrane of claim 1 , wherein the PEG-bisazide crosslinking agent has an average molecular weight (Mn) of about 1100.
10. The blended polymeric membrane of claim 1 , wherein the crosslinked PIM is blended with the co-polyimide polymeric membrane matrix.
11. The blended polymeric membrane of claim 1 , wherein the membrane demonstrates enhanced CO 2 plasticization resistance up to 800 psi CO 2 feed pressure as compared to the same blended polymeric membrane that does not incorporate a PIM crosslinked with a PEG-bisazide crosslinking agent.
12. The blended polymeric membrane of claim 1 , wherein the membrane exhibits a CO 2 -permeability increase of about 10% to about 100% as compared to the same blended polymeric membrane that does not incorporate a PIM crosslinked with a PEG crosslinking agent.
13. The blended polymeric membrane of claim 1 , wherein the membrane exhibits a CO 2 /CH 4 selectivity increase of about 10% to about 100% as compared to the same blended polymeric membrane that does not incorporate a PIM crosslinked with a PEG crosslinking agent.
14. The blended polymeric membrane of claim 1 , wherein the membrane exhibits a CO 2 /CH 4 single gas selectivity (αCO 2 /CH 4 ) of about 50 to about 60 when tested at feed temperature of 25° C. and feed pressure of 800 psi.