Method for recycling reinforced ionomer membranes

Abstract

Described herein is a method of separating components of a reinforced ionomer membrane. The reinforced ionomer membrane includes an ionomer component and a reinforcement component coupled to the ionomer component. The method includes fragmenting the reinforced ionomer membrane to produce fragmented ionomer membrane; pulverizing the fragmented ionomer membrane to form a mixture of pulverized ionomer and reinforcement fibers; and separating the ionomer component from the reinforcement component. The method is useful for recycling ionomers.

Description

FP0032-W001TITLE OF THE INVENTIONMETHOD FOR RECYCLING REINFORCED IONOMER MEMBRANESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Application No. 63 / 687,385 filed August 27, 2024, the disclosures of which are incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] This disclosure is directed to a method for separating components of a reinforced ionomer membrane. The reinforced ionomer membrane includes an ionomer component and a reinforcement component integrated with the ionomer component. The method includes pulverizing, grinding, or milling the reinforced ionomer membranes to form a mixture of the ionomer component in the form of a powder and fibers of the reinforcement component, separating the mixture of components, and isolating the ionomer component. The method is useful for recycling ionomers.BACKGROUND OF THE INVENTION

[0003] Electrochemical technologies such as fuel cells (e.g., proton exchange fuel cells and direct methanol fuel cells), water electrolyzers, chlor-alkali cells, and flow batteries are important energy sources, chemical processes, and energy storage technologies. A key component in these technologies is the membrane which separates the anode and cathode. Typical membrane materials are polymeric ionomers bearing anionic substituents such as sulfonate, phosphate, and carboxylate which are capable of binding and exchanging cations such as protons, or quaternary ammonium groups which are capable of binding and exchanging anions such as hydroxide. Examples of such ionomers are poly(perfluorosulfonic acids) such as Nation™ brand ionomers, which is manufactured by the Chemours Company.

[0004] Although the membranes in these applications can be free-standing films, in many cases the membranes are reinforced with a reinforcement component such as a polymer grid. The reinforcement component strengthens the membrane,FP0032-W001 particularly when a very thin membrane is used to minimize resistance in the cell. The reinforcement component is also helpful in maintaining mechanical integrity of the membrane under high pressure environments such as in a water electrolysis cell.

[0005] One of the unique attributes of perfluorinated ionomers is high stability to chemical attack, which makes disposal difficult. Waste perfluorinated ionomers are often land-filled or incinerated. Incineration is costly and corrosive, and conditions must be carefully controlled to eliminate the possibility of partial combustion. Given the cost of perfluorinated ionomers and difficulty of disposing of them, there is a need for a means to efficiently recover, re-process, and re-use these materials so as to minimize waste.

[0006] Various processes have been disclosed for reprocessing and recycling waste perfluorinated ionomers. Such processes typically include liquid-based techniques that require dissolution. Examples of such processes are disclosed in U.S. Patent No 4,433,082 and U.S. Patent No. 6,515,102. However, since the reinforcing component of reinforced perfluoroionomer membranes is typically insoluble, this component remains in the mixing vessel during an ionomer dispersing step. The fibrous nature of these materials poses significant problems for removing them from the reactor.

[0007] Accordingly, there is a need in the art for a process for reclaiming and reusing perfluorosulfonic acid-based ionomer membranes from fuel cells, water electrolyzers, chlor-alkali cells, and flow batteries by a process that simplifies handling of insoluble materials, such as the reinforcement component.SUMMARY OF THE INVENTION

[0008] Disclosed herein is a method for separating components of a reinforced ionomer membrane. The reinforced ionomer membrane includes an ionomer component and a reinforcement component integrated with the ionomer component. The method includes fragmenting the reinforced ionomer membrane; pulverizing, grinding, or milling the fragmented membrane to form a mixture of the powdered ionomer and the fibers of the reinforcement components, and separating the mixture of the components. The ionomer component can then be recovered and used.FP0032-W001BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 depicts an image of reinforcement fibers wrapped around the thermocouple well of a 300-cc autoclave vessel for a comparative example not in accordance with the present disclosure.

[0010] Figure 2 depicts an image of reinforcement fibers adhering to the wall of a 300-cc autoclave vessel for a comparative example not in accordance with the present disclosure.

[0011] Figure 3 depicts an image of a ground ionomer containing entangled reinforcement fibers in accordance with the present disclosure.

[0012] Figure 4 depicts an image of a ground ionomer after physical removal of the reinforcement fibers in accordance with the present disclosure.

[0013] Figure 5 depicts an image of a wet filter cake containing residual reinforcement in accordance with the present disclosure.

[0014] Figure 6 is a schematic diagram of a process for separating the ionomer component from the reinforcement component in a reinforced ionomer membrane.DETAILED DESCRIPTION OF THE INVENTION

[0015] An objective of this work is to provide a practical and scalable means of recycling pre-consumer and post-consumer ion exchange membrane waste. Disclosed herein is a method for separating an ionomer component from a reinforcement component in a reinforced ionomer membrane without need for prior dissolution of the ionomer component. The disclosed method is applicable to any ion exchange membrane having a reinforcement grid. The method is particularly applicable to reinforced perfluorosulfonic acid ionomers, mixtures of perfluorosulfonic acid ionomers, as well as laminates or combinations of perfluorosulfonic acid ionomers with perfluorocarboxylic acid ionomers or perfluorophosphonic acid ionomers.

[0016] Disclosed herein is a mechanical process that enables the physical separation of an ionomer component from a reinforcement grid in a reinforced ionomer membrane without dissolution of the ionomer component. The process includes pulverizing, grinding, or milling a reinforced ionomer membrane to produceFP0032-W001 a mixture of ionomer powder and reinforcement fibers suitable for separation. The separation process may include a screening and / or sieving process based on size and shape of the pulverized, ground, or milled components. The separated ionomer component may then be further processed to form a free-standing or reinforced ionomer film suitable for use in a number of applications.

[0017] Figure 6 depicts an exemplary schematic diagram of a process for separating the ionomer component from the reinforcement component in a reinforced ionomer membrane.Methods.

[0018] Generally, the reinforced ionomer membrane may be in any form known in the art and suitable for the method described herein. In some embodiments, the reinforced ionomer membrane is in the form of a sheet, roll, or any irregular shape or length. In some embodiments, the reinforced ionomer membrane is in the form of a sheet. In some embodiments, the reinforced ionomer membrane is in the form of a sheet comprising a reinforcement grid. In some embodiments, the reinforced ionomer membrane may be recovered waste or scrap membrane from the membrane manufacturing process such as, for example, edge trim, off-specification, damaged membranes, test samples, and / or end of roll materials. In other embodiments, the reinforced ionomer membrane may be from used or spent composite membranes recovered from electrochemical applications such as fuel cells, water electrolyzers, chlor-alkali cells, or redox flow batteries or composite membranes from non-electrochemical applications such as dehumidification, ion exchange, filtration, deacidification, and catalysis. For example, the reinforced ionomer membrane may be a used 2.7 m2sheet of laminated membrane from a chlor-alkali electrolysis cell.

[0019] In some embodiments, the reinforced ionomer membrane is in the form of a sheet comprising woven reinforcing fibers. In some embodiments, wherein the reinforced ionomer membrane is in the form of a sheet comprising woven reinforcement fibers, the woven reinforcement fibers may be individually separated by a distance in a range of from about 0.1 mm to about 1 .5 mm.

[0020] Generally, the sheets, rolls, or irregularly shaped pieces of reinforced ionomer membrane to be used for the disclosed method are reduced in size in oneFP0032-W001 or two steps. In some embodiments, the reinforced ionomer membrane is initially fragmented, or reduced to a smaller physical size, to provide fragments of the reinforced ionomer membrane having a dimensional area of about 100 cm2or less. In one aspect, fragmenting the reinforced ionomer membranes is performed by a technique including, but not limited to, cutting, slicing, chopping, shredding, granulating, or combinations thereof. In some embodiments, the ionomer membrane fragments have dimensional areas of about 0.3 cm2to about 30 cm2; in another embodiment, the ionomer membrane fragments have dimensional areas of about 0.4 cm2to about 20 cm2; in another embodiment, the ionomer membrane fragments have dimensional areas of about 0.4 cm2to about 10 cm2; and in another embodiment, the ionomer membrane fragments have dimensional areas of about 0.4 cm2to about 6 cm2.

[0021] Generally, the fragmented reinforced ionomer membrane pieces are then further reduced in size to provide a mixture comprising the finely ground ionomer component particles and coarser reinforcement fibers. According to the method of this disclosure the reinforced membrane ionomer fragments are pulverized by any technique known in the art suitable to facilitate the method described herein. In some embodiments, this comprises processing the fragmented ionomer membrane using a technique selected from the group consisting of grinding, cryogrinding, pulverizing, homogenizing, milling, ball milling, dry milling, disk milling, attrition milling, and combinations thereof. The result is a mixture of pulverized ionomer and reinforcement fibers. Surprisingly, it has been found that this method enables disengagement or release of the ionomer component from the reinforcement component.

[0022] The pulverized ionomer particles have a particle size of from about 0.2 mm to about 5 mm; in another embodiment, the ionomer particles have a particle size of from about 0.2 mm to about 3 mm; and in another embodiment, the ionomer particles have a particle size of from about 0.5 mm to about 2 mm. The reinforcement fibers have an average length of about 0.05 cm to about 15 cm; in another embodiment, the reinforcement fibers have a length of about 0.1 to about 10 cm; and in another embodiment, the reinforcement fibers have a length of about 1 to about 6 cm. In one embodiment, the ratio of reinforcement fiber length to ionomer particle size is at least about 20; in another aspect, the ratio of reinforcement fiberFP0032-W001 length to ionomer particle size is at least about 30; and in another aspect, the ratio of reinforcement fiber length to ionomer particle size is at least about 35.

[0023] As an example, in the cryogrinding technique, the fragments of reinforced ionomer membrane are cooled to a temperature from about -196°C to about 0°C, preferably from about -196°C to about -70°C, with cooling being provided by dry ice, liquid nitrogen, liquid argon, or liquid air. The membrane fragments are then subjected to a rapidly rotating gear, blade, or knife until the desired particle size is attained.

[0024] In some embodiments, a membrane is subjected to cryogrinding to provide a powdered ionomer with reinforcement fibers, where the ionomer particles have a particle size of from about 0.2 mm to about 5 mm, and the reinforcement fibers have an average length of about 1 cm to about 15 cm. Cryogrinding provides a facile means of disengaging the reinforcement component from the ionomer component due to the differing particle sizes and shapes of the two materials obtained after the final grinding process. Separation may be further affected by a sieving or screening step.

[0025] In other embodiments, a membrane may be dry milled in the absence of a solvent to provide a milled membrane consisting of the powdered ionomer with reinforcement fibers. The powdered ionomer particles component have a particle size of from about 0.2 mm to about 3 mm, and the reinforcement fibers have an average length of about 0.05 cm to about 5 cm. The mixture of milled membrane components is then screened and / or sieved to separate the reinforcement fibers and any larger pieces of membrane from the powdered ionomer component.

[0026] Regardless of the technique employed, pulverizing the reinforced ionomer membrane into smaller particles and fibers enables the separation of the finely divided ionomer component from the reinforcement component by physical means such as screening or sieving.

[0027] Without being bound to any particular theory, it is believed that the separation of the two reinforced ionomer membrane components by this method is possible due to a drastic difference in tensile properties between the ionomer component and the reinforcement component which leads to particle size and shape differentiation. The final size difference between the powdered ionomer componentFP0032-W001 and the entangled fibers of the reinforcement component is variable and dependent on the technique used to grind, pulverize, or mill the membrane.

[0028] In a preferred practice of the method, the pulverizing, grinding, and milling process is carried out as a dry method, that is, free of added solvents. It has been found that when the method includes solvents or dissolution of the ionomer during the pulverizing, grinding, and milling steps, the fibers of the reinforcement component may intertwine and become strongly adhered onto the surface of the internal parts of the equipment used resulting in increased equipment maintenance and longer processing times, thereby impeding the method.

[0029] Generally, the ionomer component may be separated from the reinforcement component according to any technique known in the art suitable to facilitate the method described herein. In some embodiments, the method includes separating the ionomer component from the reinforcement component, after the pulverizing, grinding, and milling process is carried out, based on the size and shape of the ground membrane components using a technique selected from the group consisting of screening, sieving, or filtering in a single-stage or multi-stage process. Said sieving may be assisted by means of a purge of air pressure or by means of agitation such as shaking or vibrating the sieve assembly. In these embodiments, the finely divided particles of the ionomer component are separated from the entangled fibers of the reinforcement component.

[0030] In some embodiments, the particles of the powdered ionomer component are separated from the entangled fibers of the reinforcement component by means of a sieve having a mesh size less than 5 mm, preferably less than 3 mm, especially preferably less than 2 mm. Multi-stage sieve separation can be performed using multiple mesh sizes, starting with the coarsest mesh size and ending with the finest mesh size. In these embodiments, the separated ionomer component has a particle size on the order of 100 mil, and preferably in a range of from about 5 mil to about 50 mil.

[0031] In some separation embodiments, the amount of reinforcement component collected in the separation step is at least 50% by weight of the reinforcement component in the reinforced ionomer membrane. In some separation embodiments, the amount of reinforcement component collected in the separation step is at leastFP0032-W00160% by weight of the reinforcement component in the reinforced ionomer membrane. In some separation embodiments, the amount of reinforcement component collected in the separation step is at least 70% by weight of the reinforcement component in the reinforced ionomer membrane. In some separation embodiments, the amount of reinforcement component collected in the separation step is at least 80% by weight of the reinforcement component in the reinforced ionomer membrane. In some separation embodiments, the amount of reinforcement component collected in the separation step is at least 90% by weight of the reinforcement component in the reinforced ionomer membrane.

[0032] In some embodiments, the separated reinforcement may be recycled or reprocessed. For example, poly(tetrafluoroethene) may be converted to tetrafluoroethene monomer by a thermal process as disclosed in II. S. Patent No. 2,406,153 and in much subsequent work such as described in Polymer Degradation and Stability, Vol. 83, pages 163-172 (2004).

[0033] In some embodiments, for example in chlor-alkali membranes, the reinforced ionomer membrane may also contain a gas release coating comprising particles of one or more metal oxides selected from the group consisting of zirconium oxide, cerium oxide, ruthenium oxide, manganese oxide, or mixtures thereof. Such gas release coatings may also contain, as a binder, an ionomer, such as a fluoroionomer. The ionomers may include, for example, perfluorosulfonic acid polymers, perfluorocarboxylic acid polymers, or perfluorophosphonic acid polymers. When such components are present, the method further comprises removing the gas release coating. In some embodiments, the gas release coating is removed before the membrane is subjected to pulverizing, grinding, or milling. In some embodiments, the gas release coating is removed from the ground membrane mixture after the pulverizing, grinding, or milling step. In other embodiments, the gas release coating is removed from the powdered ionomer after the reinforcement component has been separated from the ionomer component.

[0034] In some embodiments, the gas release coating is removed from the reinforced ionomer membrane, mixture of membrane components, or the separated ionomer by contact with a solvent selected from the group consisting of Ci to Cs alcohols, water, and combinations thereof. Examples of suitable alcohols includeFP0032-W001 methanol, ethanol, n-propanol, and isopropanol. In some embodiments, the solvent comprises an alcohol / water mixture comprising 20-100 weight percent water. The amount of solvent in the mixture of solvent and membrane, membrane mixture, or separated ionomer is typically from about 50 percent by weight to about 97 percent by weight based on the total weight of the mixture. Preferred solvents for removal of the gas release coating are methanol or mixtures of methanol and water such as 50 weight percent methanol in water.

[0035] In some embodiments, the contacting during gas release coating removal is conducted at a temperature of from about 20°C to about 80°C for about 0.5 hour to about 8 hours. In some embodiments, the contacting is conducted at a temperature of from about 25°C to about 50°C for about 1 hour to about 3 hours. These embodiments provide an initial mixture comprising a suspension of finely divided metal oxide(s) dispersed in the solvent along with the insoluble polymeric components such as the ionomer, the reinforcement, or the reinforced ionomer membrane. The initial mixture of metal oxides mixed with insoluble polymers may then be filtered to separate the suspension of the metal oxide from the insoluble reinforced ionomer membrane or membrane components. Said filtration may be carried out at atmospheric pressure or superatmospheric conditions, although superatmospheric conditions are seldom required.

[0036] In some embodiments, the separated reinforced ionomer membrane or membrane components are optionally recovered and re-washed, to remove any remaining metal oxides or salt contaminants, using a solvent mixture, such as water, alcohol, or water / alcohol mixture. The washing step may be repeated 1 to 3 times with solvent in the amount of from about 50 weight percent to about 97 weight percent based on the total weight of the solvent / membrane mixture. Suitable temperatures for the washing step are from about 20°C to about 60°C.

[0037] The suspension of metal oxide(s) in the processing solvent from the washing steps may be further processed to recover the metal oxide(s) by filtration or centrifugation. The recovered solvent may contain dissolved perfluoroionomer which may be recovered by precipitation or by removing the solvent under vacuum. Said solvent or solvent mixture may be recovered, optionally by distillation, and re-used.FP0032-W001

[0038] After the removal of the gas release coating, the reinforced ionomer membrane or membrane components is / are recovered and then optionally dried, for example, by means of an oven or by purging with nitrogen at elevated temperature such as from about 50°C to about 100°C. In some embodiments, the reinforced membrane ionomer or membrane components, free of gas release coating, is / are then subjected to the separation method described above. In other embodiments, when the separated particles of the ionomer component are treated to remove the gas release coating, the ionomer is washed free of metal oxide(s), isolated such as by filtration, and then carried on to the next step of the recycling process such as formation of an ionomer dispersion.

[0039] Generally, the ionomer component may be recovered according to any technique known in the art suitable to facilitate the method described herein. In some embodiments, the ionomer component is recovered according to a method comprising (i) fragmenting and grinding a reinforced ionomer membrane, (ii) separating the ground components of the reinforced ionomer membrane; and (iii) recovering the separated ionomer component.

[0040] Also disclosed herein is a process for recovering the ionomer component from a reinforced ionomer membrane comprising (i) cutting, slicing, chopping, shredding, or granulating sheets, rolls, or large pieces of a reinforced ionomer membrane to provide fragments of the reinforced membrane ionomer, (ii) subjecting the fragments of the reinforced membrane ionomer to grinding, cryogrinding, pulverizing, homogenizing, milling, ball milling, dry milling, disk milling, attrition milling, and combinations thereof, and (iii) separating the particles of powdered ionomer component from the fibers of the reinforcement component by screening or sieving in a single-stage or multi-stage process, and (iv) recovering the fragmented ionomer and fragmented reinforcement components.

[0041] Also disclosed herein is a process for recovering a perflurosulfonic acid ionomer from a reinforced perfluorosulfonic acid ionomer membrane comprising (i) cutting, slicing, chopping, shredding, or granulating sheets, rolls, or large pieces of a reinforced perfluorosulfonic acid ionomer membrane to provide fragments of the reinforced membrane, (ii) subjecting the fragments of the reinforced perfluorosulfonic acid ionomer membrane to grinding, cryogrinding, pulverizing, homogenizing, milling,FP0032-W001 ball milling, dry milling, disk milling, attrition milling, and combinations thereof, (iii) separating the particles of powdered perfluorosulfonic acid ionomer component from the fibers of the reinforcement component by screening or sieving in a single-stage or multi-stage process, and (iv) recovering the fragmented ionomer and fragmented reinforcement components.

[0042] In some embodiments, the separated fragmented PFSA ionomer may be further processed to a dispersion by treatment with solvents at elevated temperature as disclosed in the art such as U.S. 4,433,082, the teachings of which are hereby incorporated by reference. In some embodiments the solvents suitable for forming PFSA ionomer dispersion are selected from the group consisting of methanol, ethanol, n-propanol, and isopropanol, water, and mixtures of water and ethanol, n- propanol, and isopropanol.

[0043] In some embodiments, for example in chlor-alkali membranes, the reinforced membrane may contain a laminated ionomer assembly comprising one or more layers of a perfluorinated sulfonate ionomer film and one or more layers of a perfluorinated carboxylate ionomer film. Following the method of this disclosure, fragmenting and pulverizing a reinforced ionomer membrane comprising such a laminated ionomer assembly provides a finely divided ionomer component comprising a mixture of perfluorinated sulfonate ionomer(s) and perfluorinated carboxylate ionomer(s) in addition to the fibers of the reinforcement component. The separated ionomer components may be recovered and further processed, for example by dispersing in a media such as solvents suitable for forming a PFSA ionomer dispersion. Such solvents include methanol, ethanol, n-propanol, isopropanol, water, and mixtures thereof, at elevated temperatures. In dispersion mixtures where one or more perfluorinated carboxylate ionomers are present, at least a portion of these ionomers remain in a solid form and maybe recovered from the perfluorinated sulfonate ionomer dispersion by filtration.

[0044] Also disclosed herein is a powdered ionomer component recovered from a reinforced ionomer membrane according to the disclosed method.

[0045] Also disclosed herein is a perflurosulfonic acid ionomer dispersion recovered from a reinforced perflurosulfonic acid ionomer membrane according to the disclosed method.FP0032-W001

[0046] Also disclosed herein is a film cast from a perflurosulfonic acid ionomer dispersion recovered from a reinforced perflurosulfonic acid ionomer membrane according to the disclosed method.

[0047] Generally, the ionomer membrane may be selected from any product known in the art suitable for the method described herein. In some embodiments, the product is selected from the group consisting of electrochemical cell separators, catalyst-coated membranes from fuel cells or water electrolyzers, membrane electrode assemblies from fuel cells or water electrolyzers, membrane, fuel cell stacks, batteries, membranes from redox flow batteries, membranes from chlor-alkali cells, membranes from humidifiers or dehumidifiers, membranes used in ion exchange applications, membranes used in filtration applications, membranes used in deacidification applications, ionomers and membranes used in catalysis applications, and combinations thereof. In the case of the chlor-alkali electrochemical cells, the membranes are typically laminated products comprising one or more layers of perfluorosulfonic acid ionomer and one or more layers of perfluorocarboxylic acid ionomer.Materials.

[0048] The ionomer membranes to be processed by the methods and processes of this disclosure comprise at least one ionomer component and may comprise one or more reinforcement components.

[0049] The ionomer membranes to be re-processed are typically in the ionized form, that is, with the ionomeric component having anionic substituents such as - SO3M and / or CO2M where M is H, alkali metals, alkaline-earth metals, N(R6)(R7)(R8)(R9), where R6, R7, R8, and R9are the same or different and are H, CH3, or C2-C8 alkyl or aryl, and combinations thereof. This includes but is not limited to Li, Na, K, Rb, Cs, Mg, Ca, or N(R6)(R7)(R8)(R9), where R6, R7, R8, and R9are the same or different and are H, CH3, or C2-C8 alkyl or aryl and combinations thereof. Polymers bearing nonionic groups such as -SO2F or -CC CHs may be hydrolyzed with a base such as NaOH or KOH to provide an ionomer with the desired anionic substituents, such as -SOsNa and / or -CO2Na. The cation may be exchanged with other cations, e.g., H+, if desired.FP0032-W001

[0050] In some embodiments, used ionomer membranes recovered from chloralkali electrolysis applications may, in addition to the expected sodium or potassium ions, be further contaminated with other alkaline, alkaline-earth, transition, and nontransition metals which may in the form or oxide or hydroxides or at least partially bound to the ionic groups of the ionomer. Examples of other metal ions present are Mg, Ca, Ba, Ti, Fe, Ni, Zn, and Sn. Said contaminated membranes may be pretreated by soaking, washing, or rinsing with water or aqueous mineral acid, for example, sulfuric or hydrochloric acid, to remove the ionic contaminants.

[0051] Generally, one or more reinforcing components may be integrated with or embedded into the ionomer component by techniques such as casting or laminating to increase mechanical strength, chemical durability and / or dimensional stability of the final membrane. The reinforcement component may include any reinforcement grid known in the art suitable for the method described herein. The reinforcement grid can be fabricated with any process known in the art suitable for creating a lattice or network including weaving, braiding, interlacing polymer strands. Alternatively, the reinforcement grid can be fabricated by electrospinning, extrusion, or 3D printing. In some embodiments, the reinforcement component is a reinforcement grid comprising a material selected from the group consisting of poly(tetrafluoroethene), expanded poly(tetrafluoroethene), poly(ether sulfone), poly(propylene), poly(ethylene), poly(phenylene sulfide), poly(ether ether ketone) (PEEK), poly(ether sulfone), and combinations thereof.

[0052] Generally, the ionomer component may be any ionomer-containing composition known in the art suitable for the method described herein. In some embodiments, the ionomer composition is selected from the group consisting of solution-cast ionomer-containing films, reinforced ionomer-containing films, melt- extruded and hydrolyzed ionomer-containing films, reinforced extruded and hydrolyzed ionomer-containing films, and combinations thereof. In some embodiments, the ionomer-containing composition is an ionomer membrane.

[0053] Generally, the ionomer component may include any ionomer component known in the art suitable for the method described herein. In some embodiments, the ionomer is an anion exchange ionomer in which the ionomer bears cationic groups. In some embodiments, the ionomer is a cation exchange ionomer in which theFP0032-W001 ionomer bears anionic groups. Examples of ionomers bearing anionic groups are those bearing sulfonate groups or carboxylate groups. Of particular note are perfluorinated ionomers in which the anionic groups are sulfonate groups, carboxylate groups, or phosphonate groups.

[0054] In some embodiments, suitable perfluorinated ionomers comprising perfluorinated sulfonic acids and / or perfluorinated sulfonate salts, also known as PFSA ionomers, or comprising perfluorinated carboxylic acids and / or perfluorinated carboxylate salts, also known as PFCA ionomers, can be made by hydrolyzing fluorinated ionomer precursor polymers containing -SO2F endgroups to give -SO3M endgroups or by hydrolyzing fluorinated ionomer precursor polymers containing - CO2CH3 endgroups to give -CO2M endgroups, respectively. Of note are laminated ionomers comprising one or more layers of a PFSA ionomer and one or more layers of a PFCA ionomer.

[0055] Polymers bearing nonionic groups such as -SO2F or -CO2CH3 may be hydrolyzed with a base such as NaOH or KOH to provide an ionomer with the desired anionic substituents; that is, the anionic substitutents are -SO3M and / or - CO2M where M = H, Li, Na, K, Mg, Ca, or NR4 and R = alkyl, aralkyl, or aryl. The - SO3M or -CO2M endgroups may then optionally be treated with mineral acids to form -SO3H or -CO2H endgroups.

[0056] Suitable fluorinated sulfonyl fluoride ionomer precursor polymers may be prepared by polymerization or co-polymerization of at least one vinyl monomer containing at least one fluorinated sulfonyl fluoride functional group and optionally one or more additional non-functionalized vinyl co-monomers under free radical polymerization conditions. Alternatively, hydrolyzed ionomers may be prepared directly by polymerization or co-polymerization of at least one monomer containing at least one fluorinated sulfonate group and optionally one or more additional comonomers under free radical emulsion polymerization conditions. Alternatively, fluorinated sulfonyl fluoride ionomer precursor polymers or their hydrolyzed forms may be prepared by grafting sulfonyl fluoride or sulfonate substituted vinyl monomers onto a fluorinated or partially fluorinated poly(alkylene) or poly(oxyalkylene) backbone. Said monomers may be perfluorinated or at least partially fluorinated.FP0032-W001

[0057] Typically, suitable monomers containing at least one fluorinated sulfonyl fluoride functional group may have polymerizable, terminal vinyl groups such as substituted alkenyl, vinyl ether, or allyl ether groups. For example, the fluorinated sulfonyl fluoride ionomer precursor polymers may contain the repeat unit represented by the formula:-{CX2-CR1(CFR2)b-[O-(CFR3CFR4)c]a-O-(CFR5)dSO2F}- where b is 0, 1 , or 2; c is an integer from 1 to 8; a is 0, 1 , or 2; d is an integer from 1 to 8; X is H or F; and R1, R2, R3, R4, and R5are independently selected from H, F, Cl, or a perfluorinated or partially fluorinated alkyl or alkoxy group having 1 to 4 carbon atoms. For clarity, it is noted that the segment (CFR2)b-[O- (CFR3CFR4)c]a-O-(CFR5)dSO2F in the structure above is the pendant chain from the fluorinated polymer backbone and the polymerizable vinyl group, CX2=CR1-, is incorporated into the polymer backbone. Branched pendant chains having multiple sulfonyl fluoride groups are also encompassed.

[0058] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor polymer is a copolymer made from one or more sulfonyl fluoride substituted monomers and one or more nonfunctionalized vinyl co-monomers. Suitable nonfunctionalized vinyl co-monomers include, but are not limited to, tetrafluoroethylene (TFE, CF2=CF2), hexafluoropropylene (CF3CF=CF2), vinyl fluoride (CH2=CHF), vinylidene fluoride (CH2=CF2), trifluoroethylene (CHF=CF2), chlorotrifluoroethylene (CCIF=CF2), perfluoro(alkyl vinyl ethers) (e.g., perfluoro(methyl vinyl ether), CF3OCF=CF2; perfluoro(ethyl vinyl ether), C2FSOCF=CF2; and perfluoro(propyl vinyl ether), C3F?OCF=CF2) and mixtures thereof. For example, it may be a copolymer of a sulfonyl fluoride-containing monomer with TFE, resulting in a repeat unit -[CF2-CF2]-, or with other comonomers. Other nonfunctionalized vinyl co-monomers include cyclic monomers, including but are not limited to, 2-difluoromethylene-4,4,5-trifluoro-5-(trifluoromethyl)-1 ,3- dioxolane, 2-difluoromethylene-4,5-difluoro-4,5-bis(trifluoromethyl)-1 ,3-dioxolane, 2,2-bis(trifluoromethyl)-1 ,3-dioxole, 4,5-difluoro-2,2-bis(trifluoromethyl)-1 ,3-dioxole, 2,2,4,5-tetrafluoro-1 ,3-dioxole, 2,4,5-trifluoro-2-(trifluoromethyl)-1 ,3-dioxole, 2,4,5- trifluoro-2-(pentafluoroethyl)-1 ,3-dioxole, 2,2,4-trifluoro-5-(trifluoromethoxy)-1 ,3- dioxole, 4-fluoro-5-(trifluoromethoxy)-2,2-bis(trifluoromethyl)-1 ,3-dioxole, 2, 2, 3, 3,5,6-FP0032-W001 hexafluoro-2,3-dihydro-1 ,4-dioxin, 2,2,3,5,6-pentafluoro-2,3-dihydro-3- (trifluoromethyl)-l ,4-dioxin, and 2,3,5,6-tetrafluoro-2,3-dihydro-2,3- bis(trifluoromethyl)-1 ,4-dioxin.

[0059] For example, in some embodiments, a fluorinated sulfonyl fluoride ionomer precursor polymer may be a copolymer of a sulfonyl fluoride-containing monomer with TFE, resulting in a repeat unit -[CF2-CF2]-, in the backbone of the copolymer.

[0060] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor polymers include a highly fluorinated, most preferably perfluorinated, carbon backbone with a side chain represented by the formula -(O-CF2CFR4)a-O- (CF2)dSO2F, where R4is independently selected from F, Cl, or a perfluorinated alkyl group having 1 to 4 carbon atoms; a = 0, 1 or 2; and d is an integer from 2 to 6. These ionomer precursor polymers are converted to sulfonates or sulfonic acids, as disclosed, for example, in U.S. Patent No. 3,282,875, in U.S. Patent No. 4,358,545, in U.S. Patent No. 4,940,525, or in U.S. Patent No. 7,348,088.

[0061] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor includes a perfluorocarbon backbone and a side chain represented by the formula - O-CF2CF(CF3)-O-CF2CF2SO2F. Fluorinated ionomers containing sulfonate or sulfonic acid groups of this type are disclosed in U.S. Patent No. 3,282,875 and may be made by copolymerization of tetrafluoroethylene (TFE) and the perfluorinated vinyl ether CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO2F, perfluoro(3,6- dioxa-4 methyl-7-octenesulfonyl fluoride) (PSEPVE, also called long side-chain or LSC), followed by conversion to sulfonate groups by hydrolysis of the sulfonyl fluoride groups and conversion to the proton or salt form if desired for the particular application.

[0062] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor includes a perfluorocarbon backbone and a side chain represented by the formula - O-CF2CF2SO2F. Fluorinated ionomers containing sulfonate or sulfonic acid groups of this type are disclosed in U.S. Patent No. 4,358,545 and U.S. Patent No. 4,940,525. This polymer may be made by copolymerization of TFE and the perfluorinated vinyl ether CF2=CF-O-CF2CF2SO2F, perfluoro(3 oxa-4- pentenesulfonyl fluoride) (PFSVE, also called short side-chain or SSC), followed byFP0032-W001 hydrolysis and conversion to the proton or salt form if desired for the particular application.

[0063] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor includes a perfluorocarbon backbone and a side chain represented by the formula - O-CF2CF2CF2CF2SO2F. Fluorinated ionomers containing sulfonate or sulfonic acid groups of this type are disclosed in U.S. Patent No. 7,348,088. This polymer may be made by copolymerization of TFE and the perfluorinated vinyl ether CF2=CF-O- CF2CF2CF2CF2SO2F, perfluoro(5-oxa-6-heptenesulfonyl fluoride), followed by hydrolysis and conversion to the proton or salt form if desired for the particular application.

[0064] After hydrolysis and optional conversion to the proton form, a fluorinated sulfonate or sulfonic acid ionomer is formed. As used herein, sulfonate or sulfonic acid groups refers to either salts of sulfonic acid (i.e. , -SO3M endgroups, where M is a cation other than H), preferably alkali metal or ammonium salts, or sulfonic acid endgroups (i.e. -SO3H). Preferred functional groups are represented by the formula - SO3M wherein M is H, Li, Na, K, Mg, Ca, Rb, Cs, or N(R6)(R7)(R8)(R9), where R6, R7, R8, and R9are the same or different and are H, CH3, or C2-C8 alkyl or aryl. In exemplary embodiments, the fluorinated sulfonate or sulfonic acid ionomer is perfluorinated. Examples of such products include those available under the trade name of Nation™ (The Chemours Company FC, LLC, Wilmington, DE).

[0065] For example, the fluorinated sulfonate or sulfonic acid ionomer may contain the repeat unit:-{CX2-CR1(CFR2)b-[O-(CFR3CFR4)c]a-O-(CFR5)dSO3M}-

[0066] wherein b, c, a, d, R1, R2, R3, R4, and R5are as defined above and M is H, Li, Na, K, Mg, Ca or N(R6)(R7)(R8)(R9) where R6, R7, R8, and R9are the same or different and are H, CH3 or C2-C8 alkyl or aryl. For clarity, it is noted that the segment -((CFR2)b-[O-(CFR3CFR4)c]a-O-(CFR5)dSO3M)- in the structure above is the pendant chain from the perfluorinated polymer backbone. Branched pendant chains having multiple sulfonic acid groups are also encompassed.

[0067] Specific ion exchange polymer backbones may include side chains having one or more units represented by the following formulae:FP0032-W001-[O-CF2CF(CF3)-O-(CF2)d-SO3M)]- and -[O-(CF2)d-SO3M)]- wherein d is 1 -8, and M is H or an alkali metal.

[0068] In some embodiments, the ionomer backbones may include side chains having one or more units represented by the following formulae:-[O-CF2CF(CF3)-O-CF2CF2-SO3H]-[O-CF2CF(CF3)-O-CF2CF2-SO3Na]-[O-CF2CF2-SO3H]-[O-CF2CF2-SO3Na]-[O-CF2CF2CF2CF2-SO3H]-[O-CF2CF2CF2CF2-SO3Na]

[0069] wherein Q1is a perfluoroalkylene group optionally having an etheric oxygen atom, Q2is a single bond or a perfluoroalkylene group optionally having an etheric oxygen atom, R1is a perfluoroalkyl group optionally having an etheric oxygen atom, X1is an oxygen atom, a nitrogen atom or a carbon atom, such that when X1is an oxygen atom, a is 0, when X1is a nitrogen atom, a is 1 , and when X1is a carbon atom, a is 2, Y is a fluorine atom or a monovalent perfluoro organic group, r is 0 or 1 , and M is an alkali metal; or

[0070] wherein R2is a single bond or a C1-6 linear perfluoroalkylene group which may have an etheric oxygen atom, and R3is a C1-6 linear perfluoroalkylene group, mFP0032-W001 is 0 or 1 ; n is 1 , and M is an alkali metal. In some embodiments, the ion exchange polymer backbone, the main chain of a polymer, may include units represented by the following formulae:

[0071] wherein m is 0,1 or 2; n is 0, 1 or 2; Rn is a C1-6 linear perfluoroalkylene; Rf2 is a C1-6 linear perfluoroalkylene group; and M is a cation, which may be a proton, alkali metal or quaternary ammonium; or

[0072] wherein m is 0, 1 or 2; n is 0, 1 or 2; Rfi is a C1-6 linear perfluoroalkylene group; f2 is a C1-6 linear perfluoroalkylene group; and M is a cation, which may be a proton, alkali metal or quaternary ammonium. Alkali metals and quaternary ammonium suitable for use herein include, but are not limited to for example, K+, Na+and Li+, and tetramethyl ammonium, respectively.

[0073] In some embodiments, the fluorinated sulfonate or sulfonic acid has an ion exchange ratio of less than about 13.2. As used herein, ion exchange ratio (IXR) refers to the number of carbon atoms in the polymer backbone in relation to the number of sulfonyl fluoride groups. In some embodiments, the IXR of a fluorinated sulfonyl fluoride polymer can be related to the equivalent weight (EW) of the corresponding fluorinated sulfonate or sulfonic acid polymer. For example, for a copolymer of tetrafluoroethylene with a trifluorovinyl-substituted sulfonyl fluoride monomer, the equivalent is given by the equation EW = (50 x IXR) + MWSC-19, where MWSCis the molecular weight of the side chain of the fluorinated sulfonate or sulfonic acid polymer. As used herein, (EW) refers to the weight of theFP0032-W001 corresponding fluorinated sulfonic acid polymer in proton form required to neutralize one equivalent of NaOH.

[0074] In one aspect, where the fluorinated sulfonate or sulfonic acid polymer has one functional group, the fluorinated sulfonate or sulfonic acid polymer has an IXR less than about 13.2; in another aspect, less than about 12.7; in another aspect, less than about 12.1 ; and in another aspect, less than about 11.7; or any value, range, or sub-range therebetween. In one aspect, the fluorinated sulfonate or sulfonic acid polymer has an IXR of at least 7.1 ; in another aspect, at least 8.1 ; in another aspect, at least 9.1 ; and in another aspect, at least 10.1 ; or any value, range, or sub-range therebetween.

[0075] In one aspect, where the fluorinated sulfonate or sulfonic acid polymer has more than one functional group, the fluorinated sulfonate or sulfonic acid polymer has an IXR corresponding to the IXR of the preceding paragraph divided by the number of functional groups.

[0076] In one aspect, where the fluorinated sulfonate or sulfonic acid polymer has two functional groups, the fluorinated sulfonate or sulfonic acid polymer has an IXR less than about 6.6; in another aspect, less than about 6.35; in another aspect, less than about 6.05; and in another aspect, less than about 5.85; or any value, range, or sub-range therebetween. In one aspect, the fluorinated sulfonate or sulfonic acid polymer has an IXR of at least 3.55; in another aspect, at least 4.05; in another aspect, at least 4.55; and in another aspect, at least 5.05; or any value, range, or sub-range therebetween.

[0077] In some embodiments, the fluorinated sulfonate or sulfonic acid has an equivalent weight (EW) less than about 1100; alternatively less than about 1000; alternatively less than about 980; alternatively less than about 950; alternatively less than about 930, or any value, range, or sub-range therebetween. In one aspect, the ionomer precursor comprising at least one pendant -SO2F group has an EW of at least about 530; alternatively, at least about 580; alternatively, at least about 630; alternatively at least about 680, or any value, range, or sub-range therebetween.

[0078] The IXR for a fluorinated polymer with the side chain -O-CF2-CF(CF3)-O- CF2-CF2-SO3H, i.e., produced from a copolymer of TFE and PSEPVE, can be related to EW using the following formula: 50 IXR + 344 = EW.FP0032-W001

[0079] The IXR for a fluorinated polymer with the side chain -O-CF2CF2SO3H, i.e., produced from a copolymer of TFE and PFSVE, can be related to equivalent weight using the following formula: 50 IXR + 178 = EW.

[0080] In some embodiments, the ionomer membrane may further include one or more functional groups to improve ionic conductivity, selectivity, water uptake, chemical stability, and / or mechanical properties. In some embodiments, the ion exchange polymer is a cationic exchange polymer comprising a functional group selected from the group consisting of sulfonate, phosphonate, and carboxylate and derivatives thereof, and combinations thereof.

[0081] Further aspects of the present disclosure are provided by the subject matter of the following clauses:

[0082] 1 . A method of separating components of a reinforced ionomer membrane comprising: an ionomer component; and a reinforcement component coupled to the ionomer component; the method comprising: fragmenting the reinforced ionomer membrane to produce fragmented ionomer membrane; pulverizing the fragmented ionomer membrane to form a mixture of pulverized ionomer and reinforcement fibers; and separating the ionomer component from the reinforcement component.

[0083] 2. The method of the preceding clause, wherein the reinforced ionomer membrane is in a form of a sheet.

[0084] 3. The method of any preceding clause, wherein fragmenting the reinforced ionomer membrane comprises a technique selected from the group consisting of cutting, slicing, chopping, shredding, granulating, and combinations thereof.

[0085] 4. The method of any preceding clause, wherein fragmented ionomer membrane has an area of about 0.3 to about 30 cm2.

[0086] 5. The method of any preceding clause, wherein pulverizing the fragmented ionomer membrane into a fine material comprising the pulverized ionomer having aFP0032-W001 particle size of about 0.2 mm to about 5 mm and a coarse material comprising the reinforcement fibers having a fiber length of about 0.05 cm to about 15 cm.

[0087] 6. The method of any preceding clause, wherein pulverizing the fragmented ionomer membrane comprises pulverizing with a technique selected from the group consisting of grinding, cryogrinding, pulverizing, homogenizing, milling, ball milling, dry milling, disk milling, attrition milling, and combinations thereof.

[0088] 7. The method of any preceding clause, wherein the size ratio of reinforcement fiber length to ionomer particle size is at least about 20.

[0089] 8. The method of any preceding clause, wherein the reinforcement component comprises a reinforcement grid.

[0090] 9. The method of any preceding clause, wherein the reinforcement component comprises a grid with individual strands separated by a distance in a range of from about 0.1 mm to about 1.5 mm.

[0091] 10. The method of any preceding clause, wherein the reinforcement component is a reinforcement grid comprising a material selected from the group consisting of expanded polytetrafluoroethylene (ePTFE), poly(ether sulfone), poly(tetrafluoroethene), poly(propylene), poly(ethylene), poly(phenylene sulfide), poly(ether ether ketone) (PEEK), and combinations thereof.

[0092] 11. The method of any preceding clause, wherein the ionomer component comprises a material selected from the group consisting of copolymers of tetrafluoroethylene with one or more perfluorovinyl ether monomers bearing one or more sulfonate end groups, copolymers of tetrafluoroethylene with perfluorovinyl ether bearing carboxylate end groups, copolymers of tetrafluoroethylene with perfluorovinyl ether bearing phosphonate groups, and combinations thereof.

[0093] 12. The method of any preceding clause, wherein the method is a dry method free of solvents.

[0094] 13. The method of any preceding clause, wherein the steps of fragmenting the reinforced membrane and pulverizing the fragmented ionomer membrane are performed without the use of solvent.FP0032-W001

[0095] 14. The method of any preceding clause, wherein separating the ionomer component from the reinforcement component comprises a technique selected from the group consisting of sieving, single-stage size separation, multi-stage size separation, filtering, and combinations thereof.

[0096] 15. The method of any preceding clause, wherein the reinforced ionomer membrane comprises a gas release coating, wherein the method further comprises removing the gas release coating.

[0097] 16. The method of the preceding clause, wherein removing the gas release coating comprises contacting the mixture of pulverized ionomer and reinforcement fibers with a solvent and separating the resulting solid and liquid phases.

[0098] 17. A method of recovering an ionomer component, the method comprising: separating components of a reinforced ionomer membrane according to the method of any preceding clause; and recovering the ionomer component.

[0099] 18. A method of recycling an ionomer component, the method comprising: obtaining a reinforced ionomer membrane from a waste stream; and recovering the ionomer component according to the method of the preceding clause.

[0100] 19. The method of the preceding clause, wherein the waste stream is manufacturing waste or post-consumer waste.

[0101] 20. An ionomer component recovered according to the method of any preceding clause.

[0102] 21. An ionomer composition comprising the ionomer component of any preceding clause.

[0103] 22. The ionomer composition of the preceding clause, wherein the ionomer composition is selected from the group consisting of ionomer dispersions, spray- dried ionomers, cast ionomer-containing films, and combinations thereof.

[0104] 23. An ionomer membrane comprising the ionomer component of any preceding clause.

[0105] 24. A product comprising the ionomer component of any preceding clause.FP0032-W001

[0106] 25. The product of the preceding clause, wherein the product is selected from the group consisting of stacks, fuel cells, fuel cell stacks, batteries, redox flow batteries, chlor-alkali cells, electrolytic cells, electrolyzers, water electrolyzers, humidifiers, dehumidifiers, products used in ion exchange applications, products used in filtration applications, products used in deacidification applications, products used in catalysis applications, and combinations thereof.

[0107] 26. A method of forming an ionomer membrane comprising dispersing an ionomer component of any preceding clause to form an ionomer dispersion, and casting the ionomer dispersion to form an ionomer film, and producing an ionomer membrane from the ionomer film.

[0108] 27. A method of forming an ionomer membrane comprising: separating components of a reinforced ionomer membrane according to the method of any preceding clause; recovering the ionomer component; dispersing the ionomer component to form an ionomer dispersion; casting the ionomer dispersion to form an ionomer film; and producing an ionomer membrane from the ionomer film.

[0109] 28. A plurality of reinforcement fibers recovered from the method of clauses 1-16.EXAMPLES

[0110] Without further elaboration, it is believed that one skilled in the art using the preceding description can utilize the present invention to its fullest extent. The following Examples are, therefore, to be construed as merely illustrative, and not limiting of the disclosure in any way whatsoever. The starting material for the following Examples may not have necessarily been prepared by a particular preparative run whose procedure is described in other Examples. It also is understood that any numerical range recited herein includes all values from the lower value to the upper value. For example, if a range is stated as 10-50, it is intended that values such as 12-30, 20-40, or 30-50, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest valueFP0032-W001 and the highest value enumerated are to be considered to be expressly stated in this application.Materials

[0111] A perfluorinated ionomer membrane was used in each of the following examples. The perfluorinated ionomer membrane includes a woven fabric of ePTFE having a first ionomer on one side and a second ionomer on the opposing side, also including zirconium oxide particles coated on both surfaces of the membrane. The first ionomer (SR) is made of a copolymer of tetrafluoroethylene with CF2=CF-O- CF2CF(CF3)-O-CF2CF2SO3H, having equivalent weight of 920. The second ionomer (CR) is made of a copolymer of tetrafluoroethylene with CF2=CF-O-CF2CF(CF3)-O- CF2CF2COOH, having equivalent weight of 1050. The weight ratio of the first (SR) ionomer to the second ionomer (CR) is about 10. The reinforcing fabric is made of 90 denier ePTFE fibers with plain weave, having 14% weight fraction of the membrane. The zirconium oxide particles have a weight fraction less than 5 % of the membrane.

[0112] The examples below include versions of perfluorinated ionomer membrane that are either sourced from manufacturing waste or post-consumer waste.Membranes sourced from manufacturing waste have not been used in an end-use application. Post-consumer waste materials represent membranes that have been used and previously subjected to harsh conditions, including high temperature, chlorine, caustic, sodium hypochlorite, peroxides, strong oxidizing conditions.Particle Size Measurements

[0113] The post-pulverization ionomer particle size was measured according to the smallest sieve mesh that allowed passage of the powdered ionomer particles.

[0114] The reinforcement fiber length was measured by selecting 20-50 representative fibers, measuring fiber length, and averaging the results.Through-Plane Conductivity

[0115] The through-plane conductivity of a membrane was measured by a technique in which the current flowed perpendicular to the plane of the membrane. Prior to testing, the membrane was conditioned in boiling water for an hour andFP0032-W001 remained submerged in until it cooled down to room temperature and was ready to be tested. The lower electrode was formed from a 9.5 mm diameter stainless steel rod and the upper electrode was formed from a 6.35 mm diameter stainless steel rod. The rods were cut to length, and their ends were polished and plated with gold. A stack was formed consisting of lower electrode / GDE / membrane / GDE / upper electrode, where GDE is a gas diffusion electrode. The lower GDE and membrane were punched out as a 9.5 mm diameter disk, while the upper GDE was punched out as 6.35 mm diameter disks to match the upper electrode. The membrane was punched out to size while sandwiched between two pieces of Kapton film with additional water and then placed in a jar of water to ensure it did not dry out prior to testing. The stack consisting of the lower GDE, the membrane, two drops of water, and the upper GDE was assembled and held in place by a block that had a 9.5 mm diameter hole drilled into the bottom of the block to accept the lower electrode and a concentric 6.4 mm diameter hole drilled into the top of the block to accept the upper electrode. The assembly was secured with a vertical vise and torqued down to 6 Ib-in using a calibrated torque wrench to ensure low impedance ionic contact between the GDE’s and the membrane. The real part of the AC impedance of the fixture containing the membrane, Rs, was measured at a frequency of 100 kHz using a potentiostat / frequency response analyzer (PC4 / 750™ with EIS software, Gamry Instruments, Warminster, Pa.). The fixture short, Rf, was also determined by measuring the real part of the AC impedance at 100 kHz for the fixture and stack assembled without a membrane sample. The conductivity, K, of the membrane was then calculated asK=t / ((Rs-Rf)x0.317 cm2), where t was the thickness of the membrane in cm.Comparative Example 1

[0116] A 40-g sample of perfluorinated ionomer membrane manufacturing waste with a woven reinforcement and spray-coated gas release coating was hand cut into 5-10 cm2pieces for further processing. The fragmented membrane was then treated with methanol in a round-bottomed flask at 60 °C under mechanical agitation to remove the gas-release coating from the ionomer followed by a water wash and nitric acid treatment to convert the ionomer to the acid form. The fragmented membrane was then dried in a vacuum oven overnight to prepare for dissolution in aFP0032-W001300-cc autoclave. The ionomer was successfully dispersed in an ethanol-water solution to form an SR ionomer dispersion. Upon disassembly of the dispersion vessel, fibers from the woven reinforcement were found wrapped around the thermocouple well and stuck to the walls of the reactor. Figure 1 depicts an image of the reinforcement fibers wrapped around the thermocouple well of the 300cc vessel. Figure 2 depicts an image of reinforcement fibers adhering to the wall of the 300-cc vessel.Example 1

[0117] A 141 g sample perfluorinated ionomer membrane manufacturing waste containing a woven reinforcement and spray-coated gas release coating was hand cut into 5-10 cm2pieces and cryoground with dry ice in a laboratory blender. The resulting ground membrane was comprised of a large mass of entangled reinforcement fibers and ground ionomer roughly 1 mm in diameter. This mixture was treated with methanol in a round-bottomed flask under mechanical agitation at 35 °C to remove the gas release coating from the ionomer. During this process the fibrous reinforcement wrapped around the agitator shaft and was physically removed from the ionomer-solution mixture.

[0118] The contents of the flask where then filtered to isolate the ionomer from the white, spent-methanol solution containing the suspended spray-coated particles. The ionomer was then subjected to a treatment with potassium hydroxide to fully hydrolyze the ionomer followed by a nitric acid treatment to convert the ionomer to the acid form. The ionomer was then dried in a vacuum oven overnight to prepare for dissolution. A total of 75 g of ionomer was recovered. A 38 g sample of ionomer was successfully dispersed in an ethanol-water solution using a 300-cc autoclave vessel to form an SR dispersion. There was no reinforcement found on the thermocouple or reactor walls during disassembly of the vessel. The dispersion made from the recycled ionomer was cast into a 64-pm film for characterization. The film had an EW of 938 and through-plane conductivity of 58.5 mS / cm. Figure 3 depicts an image of a ground ionomer containing entangled reinforcement fibers. Figure 4 depicts an image of a ground ionomer after physical removal of the reinforcement fibers.FP0032-W001Example 2

[0119] A 138-g sample of a tan-colored, spent, post-consumer perfluorinated ionomer membrane waste containing a woven reinforcement and spray-coated gas release coating was hand cut into 5-10 cm2pieces and cryoground with dry ice in a laboratory blender. The resulting ground membrane was comprised of a large mass of entangled reinforcement fibers averaging 4.9 cm in length and ground ionomer roughly 1 mm in diameter. This mixture was treated with methanol in a round- bottomed flask under mechanical agitation at 35 °C to remove the gas release coating from the ionomer. During this process the fibrous reinforcement wrapped around the agitator shaft and was physically removed from the ionomer-solution mixture. The contents of the flask were then filtered to isolate the ionomer from the light brown, methanol suspension of spray-coated particles. The ionomer was then subjected to a nitric acid treatment to convert the ionomer to the acid form and dried in a vacuum oven overnight to prepare for dissolution. The final ionomer weight was 70g. A 27 g sample of ionomer was successfully dispersed in an ethanol-water solution using a 300-cc autoclave vessel to form an SR ionomer dispersion. There was no reinforcement found on the thermocouple or reactor walls during disassembly of the vessel. The dispersion made from the recycled ionomer was cast into a 52-pm film for characterization. The film had an EW of 973 and a through- plane conductivity of 97 mS / cm.Example 3

[0120] A sample of red-colored, iron-contaminated spent, post-consumer perfluorinated ionomer membrane waste containing a woven reinforcement and spray-coated gas release coating was hand cut into 1 cm2pieces and cryoground with dry ice in a laboratory blender. The resulting ground membrane consisted of a large mass of entangled reinforcement fibers averaging 4.7 cm in length and ground ionomer roughly 1 mm in diameter. This mixture was treated with methanol in a round-bottomed flask under mechanical agitation at 35 °C to remove the gas release coating from the ionomer. During this process the fibrous reinforcement wrapped around the agitator shaft and was physically removed from the ionomer-solution mixture. The contents of the flask were then filtered to isolate the ionomer from the red, methanol suspension of spray-coated particles. The ionomer was then treatedFP0032-W001 with nitric acid to convert the ionomer to the acid form. The ionomer still appeared red in color from iron contamination, so the ionomer was stirred in 6M hydrochloric acid overnight at room temperature. The resulting ionomer, which appeared white with a slight pink tint, was filtered, washed with water, and dried to prepare for dissolution. The recycled ionomer was successfully dispersed in an ethanol-water solution in a 300-cc autoclave vessel to form an SR ionomer dispersion. There was no reinforcement found on the thermocouple or reactor walls during disassembly of the vessel. The dispersion made from the recycled ionomer was cast into a 60-pm film for characterization. The film had an EW of 968 and a through-plane conductivity of 95.9.Example 4

[0121] A 201 g-sample of perfluorinated ionomer manufacturing membrane waste containing a woven reinforcement and spray-coated gas release coating was shredded into 4mm x 12mm pieces with a paper-shredder. The shredded ionomer was then divided into five 40 g batches for homogenization. Each batch was placed in a 1-L Nalgene bottle with 400mL of a 10 wt.% ethanol solution and homogenized at 25 rpm for 2 minutes to pulverize the ionomer. The contents of each bottle were then filtered through a coarse milk filter to isolate the ground membrane from the spent ethanol solution which appeared white in color due to the suspended spray- coated gas release particles. The ground membrane was then treated with 675 mL methanol in a round-bottomed flask under mechanical agitation at 35 °C to further remove any residual gas-release coating particles. The contents of the flask were filtered through a coarse milk filter to isolate the ground membrane from solution. 3 g of the fibrous reinforcement was wrapped around the agitator during this step and physically removed. The ground membrane was then treated with nitric acid treatment to convert the ionomer into the acid form, washed with water, and dried in a vacuum oven overnight. After drying, the ground membrane was sieved using a 3 mm screen size. 9 g of large, entangled reinforcement fibers averaging 1 .7 cm in length were retained in the coarse material and a total of 135 g of ionomer was recovered for dissolution. A 38-g sample of ionomer was successfully dispersed in a 300-cc autoclave vessel to form an SR ionomer dispersion. A small amount of residual reinforcement remaining in the ionomer was siphoned out of the reactor withFP0032-W001 the dispersion due to its small particle size. The reactor appeared clean upon disassembly. The dispersion was pressure-filtered using a coarse milk filter and the residual reinforcement was collected. The filter cake, consisting of non-dispersed CR polymer and residual reinforcement had a dry weight of 3.1 g. The dispersion underwent further processing and was cast into a film. Figure 5 depicts an image of a wet filter cake containing residual reinforcement.Example 5

[0122] A 6-lb. sample of perfluorinated reinforced ionomer membrane obtained from manufacturing waste was fed into to a granulator to produce chopped membrane roughly ! ” in diameter. The chopped film was then pulverized in a disk mill to obtain ground ionomer that was liberated from the entangled reinforcement mass. After milling, a portion of the sample was sieved using an analytical air jet sieving machine with a 30 mesh or 0.6 mm screen. The sieving step separated the entangled reinforcement from the finely ground ionomer which also included some residual finely ground reinforcement. The isolated ground ionomer accounted for 70% of the starting mass.Example 6

[0123] A 6-lb. sample perfluorinated reinforced ionomer membrane obtained from manufacturing waste was fed to a granulator to produce chopped membrane roughly V2” in diameter. The chopped film was then pulverized in a disk mill to obtain ground ionomer that was liberated from the entangled reinforcement mass. After milling, a portion of the sample was sieved using an analytical air jet sieving machine with a 30 mesh or 0.6 mm screen size. The sieving step separated the entangled reinforcement from the finely ground ionomer which also included some residual finely ground reinforcement. The isolated ground ionomer accounted for 75% of the starting mass.Example 7

[0124] A 1628-g portion of perfluorinated ionomer manufacturing waste was initially processed as in Example 6. The pulverized ionomer was shaken in a set of handheld sieves. Three different mesh sizes were used to demonstrate a multi-stageFP0032-W001 separation. The first stage used a 5 mm mesh sieves; 1243 g of fine material was recovered (76.4% of the starting material mass). The second stage used 1 mm mesh sieves; 1149 g of fine material was recovered (70.6% of the starting mass). The third and final separation stage used 0.7 mm sieves; 1012 g of fine material was recovered (62.2% of the starting mass).Conclusions

[0125] It was discovered in the present disclosure that mechanical methods of separating an ionomer component from a reinforcement component without dissolution can provide a practical, cost-effective and scalable means of recycling pre-consumer and post-consumer ionomer membrane waste into a usable ionomer film.

[0126] This written description uses examples to illustrate the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any compositions or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have elements that do not differ from the literal language of the claims, or if they include equivalent elements with insubstantial differences from the literal language of the claims.

[0127] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains”, “containing,” “characterized by” or any other variation thereof, are intended to cover a non-exclusive inclusion, subject to any limitation explicitly indicated. For example, a composition, mixture, process or method that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, mixture, process or method.

[0128] The transitional phrase “consisting of” excludes any element, step, or ingredient not specified. If in the claim, such would close the claim to the inclusion of materials other than those recited except for impurities ordinarily associated therewith. When the phrase “consisting of” appears in a clause of the body of aFP0032-W001 claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0129] The transitional phrase “consisting essentially of” is used to define a composition or method that includes materials, steps, features, components, or elements, in addition to those literally disclosed, provided that these additional materials, steps, features, components, or elements do not materially affect the basic and novel characteristic(s) of the claimed invention. The term “consisting essentially of” occupies a middle ground between “comprising” and “consisting of”.

[0130] Where an invention or a portion thereof is defined with an open- ended term such as “comprising,” it should be readily understood that (unless otherwise stated) the description should be interpreted to also describe such an invention using the terms “consisting essentially of” or “consisting of.”

[0131] Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0132] Also, the indefinite articles “a” and “an” preceding an element or component of the invention are intended to be nonrestrictive regarding the number of instances (i.e. occurrences) of the element or component. Therefore “a” or “an” should be read to include one or at least one, and the singular word form of the element or component also includes the plural unless the number is obviously meant to be singular.

[0133] As used herein, the term “about” means plus or minus 10% of the value.

[0134] As used herein, the term “ionomer” means a polymer composed of repeat units of both electrically neutral repeating units and ionized units covalently bonded to the polymer backbone as pendant group moieties. Ionomers include polymers comprising at least one pendant -SO2M group, where M is as defined above. Ionomers also include polymers comprising at least one pendant -SO2CI group.

[0135] As used herein, the term “ionomer precursor” means a polymer that may be converted to an ionomer. An ionomer precursor may be converted to an ionomer by,FP0032-W001 for example, hydrolyzation. Ionomer precursors include polymers comprising at least one pendant -SO2F group.

[0136] As used herein, the term “coupled” means a connection between components, including but not limited to, a mechanical connection, a chemical connection, and combinations thereof.

Claims

FP0032-W001CLAIMSWhat is claimed is:1 . A method of decoupling components of a reinforced ionomer membrane comprising: an ionomer component; and a reinforcement component coupled to the ionomer component; the method comprising: fragmenting the reinforced ionomer membrane to produce fragmented ionomer membrane; pulverizing the fragmented ionomer membrane to form a mixture of pulverized ionomer and reinforcement fibers; and separating the ionomer component from the reinforcement component.

2. The method of claim 1 , wherein the reinforced ionomer membrane is in a form of a sheet.

3. The method of claim 1 , wherein fragmenting the reinforced ionomer membrane comprises a technique selected from the group consisting of cutting, slicing, chopping, shredding, granulating, and combinations thereof.

4. The method of claim 1 , wherein fragmented ionomer membrane has an area of about 0.3 to about 30 cm2.

5. The method of claim 1 , wherein pulverizing the fragmented ionomer membrane comprises pulverizing the fragmented ionomer membrane into a fine material comprising the pulverized ionomer having a particle size of about 0.2 mm to about 5 mm and a coarse material comprising the reinforcement fibers having a fiber length of about 0.05 cm to about 15 cm.

6. The method of claim 1 , wherein pulverizing the fragmented ionomer membrane comprises pulverizing with a technique selected from the group consisting of grinding, cryogrinding, pulverizing, homogenizing, milling, ball milling, dry milling, disk milling, attrition milling, and combinations thereof.

7. The method of claim 1 , wherein following the pulverizing step, the size ratio of reinforcement fiber length to ionomer particle size is at least about 20.FP0032-W0018. The method of claim 1 , wherein the reinforcement component comprises a reinforcement grid.

9. The method of claim 1 , wherein the reinforcement component comprises a grid with individual fibers separated by a distance in a range of from about 0.1 mm to about 1 .5 mm.

10. The method of claim 1 , wherein the reinforcement component is a woven reinforcement component comprising a material selected from the group consisting of expanded polytetrafluoroethylene (ePTFE), poly(tetrafluoroethene), poly(ether sulfone), poly(propylene), poly(ethylene), poly(phenylene sulfide), poly(ether ether ketone) (PEEK), and combinations thereof.11 . The method of claim 1 , wherein the ionomer component comprises a material selected from the group consisting of copolymers of tetrafluoroethylene with perfluorovinyl ether bearing sulfonate end groups, copolymers of tetrafluoroethylene with perfluorovinyl ether bearing carboxylate end groups, copolymers of tetrafluoroethylene with perfluorovinyl ether bearing phosphonate groups, and combinations thereof.

12. The method of claim 1 , wherein the method is a dry method free of solvents.

13. The method of claim 1 , wherein the steps of fragmenting the reinforced membrane and pulverizing the fragmented ionomer membrane are performed without the use of solvent.

14. The method of claim 1 , wherein separating the ionomer component from the reinforcement component comprises a technique selected from the group consisting of sieving, single-stage size separation, multi-stage size separation, filtering, and combinations thereof.

15. The method of claim 1 , wherein the reinforced ionomer membrane comprises a gas release coating, wherein the method further comprises removing the gas release coating.FP0032-W00116. The method of claim 15, wherein removing the gas release coating comprises contacting the mixture of pulverized ionomer and reinforcement fibers with a solvent and separating the resulting solid and liquid phases.

17. A method of recovering an ionomer component, the method comprising: separating components of a reinforced ionomer membrane according to the method of claim 1 ; and recovering the ionomer component.

18. A method of recycling an ionomer component, the method comprising: obtaining a reinforced ionomer membrane from a waste stream; and recovering the ionomer component according to the method of claim 17.

19. The method of claim 18, wherein the waste stream is manufacturing waste or post-consumer waste.

20. An ionomer component recovered according to the method of claim 17.21 . An ionomer composition comprising the ionomer component of claim 20.

22. The ionomer composition of claim 21 , wherein the ionomer composition is selected from the group consisting of ionomer dispersions, spray-dried ionomers, cast ionomer-containing films, and combinations thereof.

23. An ionomer membrane comprising the ionomer component of claim 20.

24. A product comprising the ionomer component of claim 20.

25. The product of claim 24, wherein the product is selected from the group consisting of stacks, fuel cells, fuel cell stacks, batteries, redox flow batteries, chlor-alkali cells, electrolytic cells, electrolyzers, water electrolyzers, humidifiers, dehumidifiers, products used in ion exchange applications, products used in filtration applications, products used in deacidification applications, products used in catalysis applications, and combinations thereof.

26. A method of forming an ionomer membrane comprising dispersing an ionomer component of claim 20 to form an ionomer dispersion, casting the ionomer dispersion to form an ionomer film, and producing an ionomer membrane from the ionomer film.FP0032-W00127. A method of forming an ionomer membrane comprising: separating components of a reinforced ionomer membrane according to the method of claim 1 ; recovering the ionomer component; dispersing the ionomer component to form an ionomer dispersion; casting the ionomer dispersion to form an ionomer film; and producing an ionomer membrane from the ionomer film.

28. A plurality of reinforcement fibers recovered from the method of claims 1-16.

Images