Reinforced anion exchnage membranes and methods of making same
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- ORION POLYMER CORP
- Filing Date
- 2024-01-12
- Publication Date
- 2026-05-27
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Figure 1.1
Abstract
Description
[0001] REINFORCED ANION EXCHNAGE MEMBRANES AND METHODS OF MAKING SAME BACKGROUND 1. Field of the Disclosure The present disclosure provides an anion exchange membrane that is reinforced with a porous polymer support. More particularly, the present disclosure provides an anion exchange membrane that is impregnated with an aryl ether-free polyaromatic polymer having a random copolymer architecture with two or more aromatic ring components. 2. Discussion of the Related Art Anion exchange membranes (AEMs) are key components for electrochemical energy conversion devices such as fuel cells, electrolyzers, and flow batteries. The membranes transport anions between electrodes while preventing reactants from inter-mixing. For better performance of the devices, the membranes should have low ionic resistance, long-term durability, and good mechanical properties. Conventional AEM materials include aryl ether containing polyaromatic electrolytes because of their beneficial mechanical properties. The aryl ether group in the polymer provides flexibility into the rigid polyaromatic structure and this provides great strength to AEMs. However, the aryl ether groups are not chemically stable under high pH conditions owing to aryl ether cleavage reactions of quaternized polyaromatics, and this deteriorates membrane long-term durability. Other polymers have been developed for this purpose. (US 10,435,504, US11,040,339) Regarding ionic resistance of AEMs, membranes with higher ion exchange capacity (IEC) usually show higher anion conductivity and low ionic resistance. However, the high IEC can also cause flooding in the membrane, deteriorating its mechanical properties in high relative humidity conditions. Because of this problem with desirable property trade-offs, a lot of reinforcement methods have been developed for ion exchange membranes to possess good mechanical properties and high IEC, simultaneously. The reinforcement methods include forming composite membranes with additive fillers, pore-filled membranes, and crosslinking with additives or between polymers in the pores of support. SUMMARY The present disclosure provides a reinforced anion exchange membrane prepared by impregnating an ionic polymer into a porous membrane substrate, wherein the impregnating polymer is an aryl ether-free polyaromatic polymer having a random copolymer architecture with two or more aromatic ring components. The copolymer can be non-crosslinked or crosslinked. The latter can help to confine the polymer in the pores of the porous substrate, preventing polymer leaching. The reinforced anion exchange membrane may be useful for electrochemical energy conversion devices, e.g., AEM fuel cells, AEM electrolyzers, and flow batteries. Membranes impregnated with random copolymers using two or more different aromatic monomers employed for the aryl ether group-free quaternized polyaromatics do not currently exist. In some embodiments, the porous membrane substrates may be highly porous and thin films having a continuous porous structure from one side to the other side. The porous substrates are hydrophobic, and do not swell in water. The porous substrate is made from a material that preferably comprises high molecular weight polyethylene, ultrahigh molecular weight polyethylene, polytetrafluoroethylene, expanded polytetrafluoroethylene, polypropylene, and combinations thereof. The porous membrane substrate is not greater than about 200 microns in thickness. Some embodiments of the present disclosure include a novel method of making reinforced anion exchange membranes. The method comprises reacting two or more aromatic compounds and a trifluoromethyl ketone compound under acidic condition to produce an aryl ether-free polyaromatic polymer having random copolymer architecture with two, or more aromatic ring components; reacting the polymer with an amine to form an ionic polymer; dissolving the ionic polymer in a solvent to make a polymeric solution; and impregnating a porous membrane substrate with the polymeric solution to form a reinforced anion exchange membrane BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 shows an illustration of a method for a reinforced anion exchange membrane according to some embodiments of the invention DESCRIPTION Some embodiments of the present disclosure include reinforced anion exchange membranes prepared by impregnating an ionic polymer into a porous membrane substrate, wherein the impregnating polymer is an aryl ether-free polyaromatic polymer based on random copolymer architecture with two or more aromatic ring components. The polymer can be non-crosslinked or crosslinked, the latter to confine the polymer in the pores of the porous membrane substrate preventing the reinforced anion exchange membrane from leaching of the impregnated copolymer during operation in water. The reinforced anion exchange membrane may be useful for electrochemical energy conversion devices, e.g., AEM fuel cells, AEM electrolyzers, and flow batteries. The impregnated membranes of the present disclosure provide significantly improved mechanical (e.g. tensile) strength, chemical durability, and water management characteristics when compared to impregnated membranes that are currently available. In some embodiments, the impregnated ionic polymer has the following formula I: … random copolymers, wherein Arn is 2 to 20, wherein each of a1, a2, a3, … and an is, independently, 1 to 1,000,000, wherein R1, R2, R3, … and Rn, wherein Rn is 2 to 20, include
[0002] , or com natons tereo, weren ncues , , ,2,an a y group, or com natons tereof; A’ includes N, an alkyl group, or combinations thereof; X includes a halide, e.g., Br; FG includes NR3+X–, NR3+OH–, OH, NR2, SO3H, P(=O)(OH)2, CO2H, SO3–M+, P(=O)(O–)22M+, CO2–M+(M = Li, Na, K), linear multi-quaternary ammonium groups, branched multi-quaternary ammonium groups, or combinations thereof; FG’ includes NR2+X–, NR2+OH–; R is an alkyl group, e.g., CH3or CH2CH3; m is from 0 to 20; and n is from 0 to 20. In one embodiment, a “random copolymer” is one that is composed of two or more different monomers with a completely random sequence of repeat units. In some embodiments, Ar1, Ar2, Ar3, … and Arncan be
[0003] , or combinations thereof, wherein R includes an alkyl group, e.g., CH3 or CH2CH3, a halide, e.g., F, or combinations thereof; R' includes H, an alkyl group, e.g., CH3or CH2CH3, or combinations thereof; X includes a halide; A includes S, O, NH, SO2, an alkyl group, e.g., CH2or CH2CH3, or combinations thereof; and n is from 0 to 20. The ionic polymer having two or more aromatic rings components is contained in the pores of a porous membrane substrate. In some embodiments, the porous substrates may be highly porous and thin films having a continuous porous structure from one side to the other side. The porous substrates are hydrophobic, and it doesn’t swell in water. The porous substrate preferably comprises a material selected from high molecular weight polyethylene, ultrahigh molecular weight polyethylene, polytetrafluoroethylene, expanded polytetrafluoroethylene, or polypropylene. The porous substrate is preferably not greater than about 200 microns in thickness, more preferably less than about 50 microns. In some embodiments, the porous substrate has porosity greater than 30%, preferably greater than 70%. Preferred substrate membranes have a pore size of from 0.05 micron to 1.0 microns. In some embodiments, the pore-filled reinforced membrane contains the ionic polymer greater than 30 wt.%, preferably greater than 70 wt.%. Some embodiments of the present disclosure include novel methods of making the reinforced anion exchange membranes. The method comprises reacting two or more aromatic compounds and a trifluoromethyl ketone compound under acidic conditions to produce aryl ether-free polyaromatic based on random copolymer architecture with two or more aromatic ring components; reacting the polyaromatic with an amine to form an ionic polymer; dissolving the ionic polymer in a solvent to make a polymeric solution; and impregnating a porous membrane substrate with the polymeric solution to form a reinforced anion exchange membrane. In some embodiments, the R1, R2, R3, … or Rn are partially crosslinked by a crosslinking agent selected from a group consisting of: multi- amines or combinations thereof, wherein R include H, an alkyl group, such as for example, CH3 or CH2CH3, or combinations thereof; and n is from 0 to 20. In some embodiments the copolymer has a degree of crosslinking of from 0% to 100%, or any subranges therebetween. The crosslinking reaction takes place in the pores of the porous substrate to confine the copolymer in the pores preventing the reinforced anion exchange membrane from leaching of the impregnated copolymer during operations.
Claims
CLAIMS 1. A method of making a reinforced anion exchange membrane, comprising: reacting two or more aromatic compounds and a trifluoromethyl ketone compound under acidic condition to produce a precursor copolymer; reacting the precursor copolymer with an amine to form an ionic polymer; dissolving the ionic polymer in a solvent to make a polymeric solution; and impregnating a porous membrane substrate with the polymeric solution to form a reinforced anion exchange membrane.
2. The method of claim 1, wherein the aromatic compounds are selected from the group consisting of:, and combinations thereof, wherein R includes an alkyl group, e.g., CH3or CH2CH3, a halide, e.g., F, or combinations thereof; R' includes H, an alkyl group, e.g., CH3or CH2CH3, or combinations thereof; X includes a halide; A includes S, O, NH, SO2, an alkyl group, e.g., CH2or CH2CH3, and combinations thereof; and n is from 0 to 20.
3. The method of claim 1, wherein the trifluoromethyl ketone compound is selected from the group consisting of: O (CH2)nCH3F3C F3C F3C ,n Xnn , ,thereof; A’ includes N, an alkyl group, or combinations thereof; X includes a halide, e.g., Br; and n is from 0 to 20.
4. The method of claim 1, wherein the amine is selected from the group consisting of: trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, tripentylamine, trihexylamine, N,N-diisopropylmethylamine, N-isopropyl-N-methyl-tert-butylamine, N- methylpiperidine, N-methylpyrrolidine, 1-ethylpyrrolidine, 1-butylpyrrolidine, 1,2,2,6,6- pentamethylpiperidine, diamines, multi-amines and combinations thereof.
5. The method of claim 1, wherein the solvent is selected from a group consisting of toluene, tetrahydrofuran, dichloromethane, chloroform, chlorobenzene, 1,2-dichlorobenzene, 1,3- dichlorobenzene, nitrobenzene, dimethylformamide, dimethylacetamide, dimethylsulfoxide, N- methyl-2-pyrrolidone, methanol, ethanol, 1-propanol, 2-propanol, or combinations thereof 6. The method of claim 1, wherein the porous membrane substrate comprises a polymer selected from a group consisting of high molecular weight polyethylene, ultrahigh molecular weight polyethylene, polytetrafluoroethylene, expanded polytetrafluoroethylene, polypropylene or combinations thereof.
7. The method of claim 1, wherein thickness of the porous membrane substrate is less than about 200 microns.
8. The method of claim 1, wherein thickness of the porous membrane substrate is about 10 - 50 microns.
9. The method of claim 1, wherein the ionic copolymer is according to Formula I:wherein Ar1, Arnare different aryl groups to form random copolymers, and are selected from the group consisting of:a halide, or combinations thereof, wherein n is 2 to 20, wherein each of a1, … and an is, independently, 10 to 1,000,000, wherein each of R1, … and Rn is independently:from 0 to 20, wherein FG is selected from the group consisting of NR3+X–, NR3+OH–, OH, NR2, SO3H, P(=O)(OH)2, CO2H, SO3–M+, P(=O)(O–)22M+, CO2–M+(M = Li, Na, K), linear multi-quaternary ammonium groups, branched multi-quaternary ammonium groups, crosslinked multi-quaternary ammonium groups, and combinations thereof, and R is an alkyl group, and X is a halide.
10. A reinforced anion exchange membrane, comprising: a porous membrane substrate; and an ionic polymer according to Formula I, impregnated into pores of the porous membrane substrate… are groups to random copolymers, wherein Arn is 2 to 20, wherein each of a1, a2, a3, … and an is, independently, 1 to 1,000,000, wherein R1, R2, R3, … and Rn, wherein Rn is 2 to 20, include, thereof; A’ includes N, an alkyl group, or combinations thereof; X includes a halide, e.g., Br; FG includes NR3+X–, NR3+OH–, OH, NR2, SO3H, P(=O)(OH)2, CO2H, SO3–M+, P(=O)(O–)22M+, CO2–M+(M = Li, Na, K), linear multi-quaternary ammonium groups, branched multi- quaternary ammonium groups, or combinations thereof; FG’ includes NR2+X–, NR2+OH–; R is an alkyl group, e.g., CH3 or CH2CH3; m is from 0 to 20; and n is from 0 to 20.
11. The reinforced anion exchange membrane of claim 9, wherein Ar1, Ar2, Ar3, … and Arn is independently selected from the group consisting of:, and comb nat ons t ereo , w ere n nc udes an a y group, e.g., C3or CH2CH3, a halide, e.g., F, or combinations thereof; R' includes H, an alkyl group, e.g., CH3or CH2CH3, or combinations thereof; X includes a halide; A includes S, O, NH, SO2, an alkyl group, e.g., CH2or CH2CH3, and combinations thereof; and n is from 0 to 20.
12. The reinforced anion exchange membrane of claim 9, wherein the porous membrane substrate comprises a polymer selected from the group consisting of: high molecular weight polyethylene, ultrahigh molecular weight polyethylene, polytetrafluoroethylene, polypropylene or combinations thereof.
13. The reinforced anion exchange membrane of claim 9, wherein thickness of the reinforced anion exchange membrane is less than or equal to about 200 microns.
14. The reinforced anion exchange membrane of claim 9, wherein thickness of the reinforced anion exchange membrane is about 10 - 50 microns.
15. The reinforced anion exchange membrane of claim 9, wherein the reinforced anion exchange membrane has an ion exchange capacity of from about 0.5 to about 5.0 mequiv. / g.
16. The reinforced anion exchange membrane of claim 9, wherein a portion of R1, R2, R3, … and Rnis crosslinked by a diamine selected from the group consisting of:multi-amines or combinations thereof, wherein R include H, an alkyl group, e.g., CH3 or CH2CH3, and combinations thereof; and n is from 0 to 20.
17. A reinforced anion exchange membrane, comprising: a porous membrane substrate; and an ionic polymer according to Formula II, impregnated into pores of the porous membrane substratewherein m and n is 1 to 1,000,000.
18. The reinforced anion exchange membrane of claim 16, wherein the porous membrane substrate comprises a polymer selected from the groups consisting of high molecular weight polyethylene, ultrahigh molecular weight polyethylene, polytetrafluoroethylene, polypropylene or combinations thereof.
19. The reinforced anion exchange membrane of claim 16, wherein thickness of the reinforced anion exchange membrane is less than or equal to about 200 microns.
20. The reinforced anion exchange membrane of claim 16, wherein thickness of the reinforced anion exchange membrane is about 10 - 50 microns.
21. The reinforced anion exchange membrane of claim 16, wherein the reinforced anion exchange membrane has an ion exchange capacity of from about 0.5 to about 5.0 mequiv. / g.
22. The reinforced anion exchange membrane of claim 1, wherein the ionic copolymer is according to Formula I:wherein Ar1, Arn are different aryl groups to form random copolymers, and are selected from the group consisting of:a halide, or combinations thereof, wherein n is 2 to 20, wherein each of a1, … and an is, independently, 10 to 1,000,000, wherein each of R1, … and Rnis independently: x FG wherein x is from 0 to 20,wherein FG is selected from the group consisting of NR3+X–, NR3+OH–, OH, NR2, SO3H, P(=O)(OH)2, CO2H, SO3–M+, P(=O)(O–)22M+, CO2–M+(M = Li, Na, K), linear multi-quaternary ammonium groups, branched multi-quaternary ammonium groups, crosslinked multi-quaternary ammonium groups, and combinations thereof, and R is an alkyl group, and X is a halide.