Method for converting ionomers

Abstract

Described herein is a method including (I) forming a first mixture including: an ionomer including at least one pendant -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof; a chlorination reagent; and a chlorination solvent; (II) reacting the first mixture to produce an at least partially chlorinated ionomer including at least one pendant -SO2Cl group; (III) forming a second mixture including: the at least partially chlorinated ionomer including at least one pendant -SO2Cl group; a fluorination reagent; and optionally a fluorination solvent; and (IV) reacting the second mixture to produce a sulfonyl fluoride-containing polymer including at least one pendant -SO2F group. The method is useful for recycling ionomers.

Description

FP0022-WG01 (45985-18)METHOD FOR CONVERTING IONOMERSGOVERNMENT SUPPORT CLAUSE

[0001] This invention was made with government support under W911 NF2320017 awarded by the Army Research Office (ARO). The government has certain rights in the invention.FIELD OF DISCLOSURE

[0002] This disclosure is directed to a method useful for converting polymers having -SOsM groups, where M is H, alkali metals, alkaline-earth metals, or combinations thereof, to melt-processible polymers having -SO2F groups, which is particularly useful for recycling ionomers.BACKGROUND

[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, or energy storage technologies. A key component in these technologies is the membrane which separates the anode from the cathode. Typical membrane materials comprise perfluoroionomers bearing anionic substituents, such as sulfonate groups, which are capable of binding and exchanging cations such as H+, Na+, and K+. In perfluorosulfonic acid (PFSA) ionomers, the sulfonate groups are typically formed by hydrolysis of pendant -SO2F groups present in precursor polymers. PFSA ionomers are characterized by high conductivity, long operational life, and good stability.

[0004] In the interest of efficient resource utilization and waste minimization, there is a need for methods suitable for recycling PFSA ionomers used in these technology areas. Such methods would allow manufacturing waste or used membranes from fuel cells, fuel cell stacks, redox flow batteries, chlor-alkali cells, electrolytic cells, water electrolyzers, humidifiers, dehumidifiers, ion exchange applications, filtration applications, deacidification applications, and catalysis applications to be re-extruded and reused. Such methods are especially desirable for perfluorosulfonic acid ionomers since these are typically manufactured in an extrudable form, but used in a hydrolyzed form.

[0005] However, existing methods for recycling hydrolyzed PFSA ionomers to an extrudable form, for example by converting -SO3H groups in the ionomer to -SO2FFP0022-W001 (45985-18) groups, are insufficient. Most recycling methods are unable to recycle ionomers by this type of transformation. In addition, the few available methods, such as those disclosed in U.S. 4,266,036, require hazardous reactants and reaction conditions and have not been demonstrated to be efficacious.BRIEF DESCRIPTION OF THE DISCLOSURE

[0006] Accordingly, the present application seeks to provide methods useful for recycling ionomers containing -SO3H groups (e.g., PFSA ionomers). In particular, it has been found that hydrolyzed PFSA ionomers may be recovered and recycled by chlorination of a hydrolyzed form of the ionomer to produce an at least partially chlorinated form of the ionomer, with subsequent fluorination of the at least partially chlorinated form to produce an at least partially fluorinated form of the ionomer.

[0007] In one aspect, provided herein is a method including (I) forming a first mixture including: an ionomer including at least one pendant -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof; a chlorination reagent; and a chlorination solvent; (II) reacting the first mixture to produce an at least partially chlorinated ionomer including at least one pendant - SO2CI group; (III) forming a second mixture including: the at least partially chlorinated ionomer including at least one pendant -SO2CI group; a fluorination reagent; and optionally a fluorination solvent; and (IV) reacting the second mixture to produce a sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group.DETAILED DESCRIPTION OF THE DISCLOSURE

[0008] The present disclosure is directed to a method including (I) forming a first mixture including: an ionomer including at least one pendant -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof; a chlorination reagent; and a chlorination solvent; (II) reacting the first mixture to produce an at least partially chlorinated ionomer including at least one pendant - SO2CI group; (III) forming a second mixture including: the ionomer including at least one pendant -SO2CI group; a fluorination reagent; and optionally a fluorination solvent; and (IV) reacting the second mixture to produce a sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group. The sulfonyl fluoride-FP0022-W001 (45985-18) containing polymer can be used as a precursor for a further ionomer by subsequent processing steps.

[0009] In some embodiments, the alkali metals are selected from Li, Na, K, Rb, Cs, and combinations thereof.

[0010] In some embodiments, the alkaline-earth metals are selected from Mg, Ca, Sr, Ba, and combinations thereof.

[0011] In some embodiments, disclosed herein is method for converting an ionomer including SOsH groups to an ionomer precursor in which at least some of the SO3H groups have been converted to -SO2F groups. In some embodiments, disclosed herein is method for converting a PFSA ionomer in the hydrolyzed form to a PFSA ionomer precursor in which at least some of the SO3H groups have been converted to -SO2F groups.

[0012] In some embodiments, disclosed herein is method for converting an ionexchange ionomer including SO3M groups, wherein M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof, including but not limited to Li, Na, K, Rb, Cs, and combinations thereof, to a fluorinated form of the ionomer in which at least some of the SO3M groups have been converted to -SO2F groups. In some embodiments, disclosed herein is method for converting an ion exchange PFSA ionomer in which at least some of the SO3M groups in the ionomer have been converted to -SO2F groups.

[0013] In some embodiments, disclosed herein is a method of recycling an ionomer. In some embodiments, disclosed herein is a method of recycling a PFSA ionomer.

[0014] One benefit of the present disclosure is high conversion of a hydrolyzed form of an ionomer (e.g., a PFSA ionomer) to an at least partially fluorinated form of the ionomer in the form of a sulfonyl fluoride-containing polymer. This high conversion allows melt processing of the sulfonyl fluoride-containing polymer. A high conversion of the ionomer to the sulfonyl fluoride-containing polymer also allows removal of reactive endgroups by reaction with elemental fluorine.

[0015] In step I, a first mixture is formed containing an ionomer component in the first mixture which comprises at least one pendant -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof, which mayFP0022-W001 (45985-18) include any ionomer comprising at least one pendant -SO3M group known in the art suitable to facilitate the method described herein. In some embodiments, the ionomer comprising at least one pendant -SO3M group is selected from perfluorosulfonic acid ionomers, at least partially fluorinated sulfonic acid ionomers, and combinations thereof.

[0016] Generally, the ionomer comprising at least one pendant -SO3M group may be in any form known in the art suitable to facilitate the method described herein. The form may include combinations of characteristics, such as source and morphology. In some embodiments, the ionomer comprising at least one pendant -SO3M group is in a form selected from films, sheets, rolls, membranes, pellets, extrudates, particles, spray-dried particles, chips, flakes, powders, and combinations thereof. In some embodiments, the ionomer comprising at least one -SO3M group may be obtained from new ionomers, used ionomers, waste ionomers, and recycled ionomers.

[0017] In some embodiments, the ionomer comprising at least one pendant - SO3M group is recovered from manufacturing waste. In some embodiments, the ionomer comprising at least one pendant -SO3M group is virgin material recovered from manufacturing waste.

[0018] In some embodiments, the ionomer comprising at least one pendant - SO3M group is in a form of a used or spent membrane from an application selected from fuel cell (FC) applications, water electrolysis (WE) applications, flow battery (FB) applications, chlor-alkali (CA) applications, catalyst applications, and combinations thereof.

[0019] In some embodiments, the ionomer comprising at least one pendant - SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 5 pm to about 75 pm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 10 pm to about 50 pm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm; in another aspect, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range ofFP0022-WG01 (45985-18) from about 1 pm to about 5 mm; and in another aspect, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 2 mm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is first obtained in the form of large format, such as a sheet, roll, or membrane, and the particle size is reduced to form a particle, spray-dried particle, chip, flake, powder, or combination thereof. In one aspect, the method further comprises the step of reducing the size of the ionomer comprising at least one pendant -SO3M group before step I. Some methods for reducing the particle size include, but are not limited to, grinding or pulverizing, as described in US 4,266,036, or spray drying.

[0020] In some embodiments, the ionomer comprising at least one pendant - SO3M group is a PFSA ionomer in a form of spray-dried particles. Spray-dried PFSA ionomers may be obtained from dispersions of PFSA ionomers as disclosed in U.S. Patent No 7,989,513, the teachings of which are incorporated herein.

[0021] In some embodiments, the ionomer comprising at least one pendant - SO3M group is a PFSA ionomer in a form of spray-dried particles having a particle size D50 in a range of from about 1 pm to about 100 pm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is a PFSA ionomer in a form of spray-dried particles having a particle size D50 in a range of from about 5 pm to about 75 pm. In some embodiments, the ionomer comprising at least one pendant - SO3M group is a PFSA ionomer in a form of spray-dried particles having a particle size D50 in a range of from about 10 pm to about 50 pm.

[0022] Generally, the ionomer comprising at least one pendant -SO3M group may have any equivalent weight known in the art suitable to facilitate the method described herein. In some embodiments, the ionomer comprising at least one pendant -SO3M group has an equivalent weight in a range of from about 700 to about 1500.

[0023] Generally, the ionomer comprising at least one pendant -SO3M group may have any ion exchange ratio known in the art suitable to facilitate the method described herein. In some embodiments, the ionomer comprising at least oneFP0022-WG01 (45985-18) pendant -SO3M group has an ion exchange ratio in a range of from about 3.55 to about 13.2.

[0024] Generally, it is preferable that the ionomer comprising at least one pendant -SO3M group may have any ion exchange ratio known in the art suitable to facilitate the method described herein. In some embodiments, the ionomer comprising at least one pendant -SO3M group has an ion exchange ratio in a range of from about 3.55 to about 13.2.

[0025] Generally, it is preferable that the ionomer comprising at least one pendant -SO3M group contains a minimal amount of adsorbed water. Since perfluorinated ionomers are hygroscopic, the water content of the ionomer is preferably reduced by one or more methods to a level below about 6 weight percent; in another aspect, below about 4 weight percent; in another aspect, below about 3 weight percent; in another aspect, below about 2 weight percent; and in another aspect, below about 1 weight percent; all based on the total weight of the ionomer.

[0026] In some embodiments, the water content of the ionomer to be processed by this method is further reduced by drying prior to forming the first mixture. The ionomer may be dried, for example, in an oven, drying tube, or the container to be used for forming the first mixture. The drying step may be conducted at a temperature of from about 40 °C to about 130 °C; in another aspect, about 40 °C to about 120 °C; in another aspect, about 60 °C to about 120 °C; in another aspect, about 40 °C to about 110 °C; and in another aspect, about 60 °C to about 110 °C. The pressure of the drying step may be atmospheric pressure, optionally with a dry inert gas purge on the vessel (e.g., with nitrogen). In one aspect, the drying step may be conducted at a reduced pressure of from about 0.006 kPa to about 70.9 kPa; in another aspect, about 10.1 kPa to about 70.9 kPa (about 0.1 to about 0.7 atmospheres); in another aspect, about 0.006 kPa to about 60.0 kPa, in another aspect, about 0.006 kPa to about 50.0 kPa; and in another aspect, about 0.006 kPa to about 41.0 kPa. Suitable drying times are from about 1 hour to about 20 hours. Preferably, the drying step reduces the water content of the ionomer to a level below about about 6 weight percent; in another aspect, below about 4 weight percent; in another aspect, below about 3 weightFP0022-WG01 (45985-18) percent; in another aspect, below about 2 weight percent; and in another aspect, below about 1 weight percent.

[0027] Generally, the chlorination reagent component in the first mixture may include any chlorination reagent known in the art suitable to facilitate the method described herein. In some embodiments, the chlorination reagent is selected from phosphorus(V) chlorination reagents such as RPCk wherein R is selected from Cl, alkyl, haloalkyl, aryl, and combinations thereof, and phosphorus(V) chlorination reagents generated in situ from a phosphorus(lll) precursor reagent such as RPCh wherein R is as defined above, by reaction of the phosphorus(lll) precursor reagent with CI2. Of note is the generation of the chlorination reagent phenyltetrachlorophosphorane, CeHsPCU, by reaction of phenyldichlorophosphine, CeHsPCh, with CI2.

[0028] Generally, the chlorination solvent component in the first mixture may include any chlorination solvent known in the art suitable to facilitate the method described herein. In some embodiments, the chlorination solvent is selected from solvents which are inert to CI2 and strong Lewis acids and have a boiling point greater than about 80 °C. In some aspects, the chlorination solvent has a boiling point less than about 250 °C. Groups of solvents suitable as chlorination solvents include halogenated arenes (e.g., chlorobenzene, fluorobenzene, difluorobenzene, 1 ,2- dichlorobenzene, and 1 ,2,4-trichlorobenzene), and trifluoromethyl-substituted arenes (e.g., benzotrifluoride and hexafluoro-m-xylene), trifluoromethyl-substituted halogenated arenes (e.g., 4-chlorobenzotrifluoride, 2-chlorobenzotrifluoride (CBTF), 2,4-dichlorobenzotrifluoride, and 3,4-dichlorobenzotrifluoride), and combinations thereof.

[0029] In some embodiments, a first mixture is formed containing the ionomer comprising at least one pendant -SO3M group, a chlorination solvent, and a phosphorus(lll) precursor reagent, RPCh, where R is selected from Cl, alkyl, haloalkyl, aryl, and combinations thereof and where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof. The resulting mixture is then reacted with chlorine (Ch) to form the chlorination reagent, RPCI4. This prechlorination step may be carried out at atmospheric pressure at a temperature of from about 0 °C to about 80 °C. In some embodiments, the pre-chlorination step is carried at a temperature of from about 10 °C to about 50 °C. The amount of chlorine addedFP0022-W001 (45985-18) is typically enough to fully convert the phosphorus(lll) precursor reagent to the phosphorus(V) chlorination reagent. Typically, from about 1.0 mole to about 1.2 moles of chlorine per mole of phosphorus(lll) reagent are added to the reactor to ensure complete reaction. The chlorine is typically added in the vapor form at a rate sufficient to control the reaction exotherm which subsides when the chlorination of the phosphorus(lll) precursor reagent is complete, that is, when the phosphorus(lll) precursor reagent has been consumed and the phosphorus(V) chlorination reagent has formed.

[0030] In some embodiments, a pre-mixture is initially formed containing a chlorination solvent and a phosphorus(lll) precursor reagent. This pre-mixture is then reacted with chlorine to fully convert the phosphorus(lll) precursor reagent to the phosphorus(V) chlorination reagent and provide a mixture comprising a phosphorus(V) chlorination reagent and a chlorination solvent. The ionomer comprising at least one pendant -SOsM group is then added to the pre-formed phosphorus(V) chlorination reagent to form the first mixture.

[0031] In other embodiments, a pre-mixture is initially formed containing a chlorination solvent, the ionomer comprising at least one pendant -SO3M group, and a dehydrating or desiccating agent. Examples of dehydrating or desiccating agents include the phosphorus(lll) precursor reagent, RPCI2, where R is as defined above or the oxide form of the phosphorus(lll) precursor reagent, RP(O)Cl2, where R is as defined above. The dehydrating agent need not be derived from the chlorination reagent. For example, the dehydrating agent may be POCI3 and the chlorination reagent may be CeHsPCk The pre-mixture containing the dehydrating agent is then mixed at a temperature of about 25 °C to about 100 °C for a time sufficient to remove water from the mixture, for example, for a time of about one hour to about 10 hours. After the dehydrating step is completed, the mixture is typically cooled to a temperature of from about 10 °C to about 40 °C and then the phosphorus(V) chlorination reagent is added to form the first mixture.

[0032] In some embodiments, the phosphorus(lll) precursor is added to the dehydrated pre-mixture followed by the chlorination step to generate the phosphorus(V) chlorination reagent and to form the first mixture. In otherFP0022-W001 (45985-18) embodiments, the phosphorus(V) chlorination reagent is then added to the dehydrated pre-mixture to form the first mixture.

[0033] In step II, the first mixture may be reacted under any reaction conditions known in the art suitable to facilitate the method described herein to form an at least partially chlorinated ionomer. In some embodiments, reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 80 °C to about 150 °C. In some embodiments, reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 85 °C to about 135 °C. In other embodiments, reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 100 °C to about 135 °C. In other embodiments, reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 90 °C to about 135 °C; and in other embodiments, reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 90 °C to about 125 °C

[0034] In some embodiments, reacting the first mixture comprises reacting the first mixture at atmospheric pressure. In some embodiments, reacting the first mixture comprises reacting the first mixture at elevated pressure.

[0035] In some embodiments, reacting the first mixture comprises reacting the first mixture for a time in a range of from about 1 hour to about 24 hours. In some embodiments, reacting the first mixture comprises reacting the first mixture for a time in a range of from about 1 hours to about 12 hours. In some embodiments, reacting the first mixture comprises reacting the first mixture for a time in a range of from about 4 hours to about 12 hours. In some embodiments, reacting the first mixture comprises reacting the first mixture for a time in a range of from about 2 hours to about 8 hours. In some embodiments, reacting the first mixture comprises reacting the first mixture for a time in a range of from about 4 hours to about 8 hours.

[0036] Generally, the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group may be processed with any technique known in the art suitable to facilitate the method described herein. In some embodiments, the method further comprises processing the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof. In some embodiments, theFP0022-W001 (45985-18) ionomer comprising at least one pendant -SO2CI group is not processed after reacting the first mixture.

[0037] In some embodiments, the ionomer comprising at least one pendant - SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm. In some embodiments, the ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 5 pm to about 75 pm. In some embodiments, the ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 10 pm to about 50 pm. In some embodiments, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm; in another aspect, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 5 mm; and in another aspect, the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 2 mm. In some embodiments, the ionomer comprising at least one pendant -SO2CI group is first obtained in the form of large format, such as a sheet, roll, or membrane, and the particle size is reduced to form a particle, spray-dried particle, chip, flake, powder, or combination thereof. In some embodiments, the ionomer comprising at least one pendant -SO2CI group is first obtained in the form of large format, such as a chip or flake, and the particle size is reduced to form a particle, spray-dried particle, powder, or combination thereof. In one aspect, the method further comprises the step of reducing the size of the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group before step III. Some methods for reducing the particle size include, but are not limited to, grinding, pulverizing, or spray drying.

[0038] In some embodiments, the method further comprises recovering the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture.

[0039] In step III, a second mixture is formed containing the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group, a fluorination reagent, and a fluorination solvent. Generally, the fluorination reagent may include any fluorination reagent known in the art suitable to facilitate the method describedFP0022-WG01 (45985-18) herein to form a sulfonyl fluoride-containing polymer. In some embodiments, the fluorination reagent is selected from alkali metal fluorides (e.g., lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, and combinations thereof).

[0040] Generally, the fluorination solvent may include any fluorination solvent known in the art suitable to facilitate the method described herein. In some embodiments, the fluorination solvent is selected from anhydrous polar aprotic organic solvents, such as nitriles (e.g., acetonitrile, propionitrile, butyronitrile, benzonitrile), carboxylic amides (e.g., N,N-dimethylformamide (DMF), N,N- dimethylacetamide (DMAc), N-methyl formamide, or formamide), heterocyclic amides (e.g., 1 ,3-dimethyl-2-imidazolidinone (DMI)), sulfoxides (e.g., dimethyl sulfoxide (DMSO)), and sulfones (e.g., tetramethylene sulfone (sulfolane)), and combinations thereof. By anhydrous is meant having a water content of less than 500 ppm, and most preferably less than about 100 ppm. Water content in the solvents may be minimized by any mean known in the art such as by distillation in the presence of a dessicant or by storage over a drying agent such as 3 Angstrom molecular sieves.

[0041] In step IV, the second mixture is reacted to form a sulfonyl fluoride- containing polymer comprising at least one pendant -SO2F group. Generally, the second mixture may be reacted under any reaction conditions known in the art suitable to facilitate the method described herein. In some embodiments, reacting the second mixture comprises reacting the second mixture at atmospheric pressure. In some embodiments, reacting the second mixture comprises reacting the second mixture at elevated pressure.

[0042] In some embodiments, reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 25 °C to about 120 °C. In some embodiments, reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 40 °C to about 100 °C.

[0043] In step IV, the second mixture is reacted to form a sulfonyl fluoride- containing polymer comprising at least one pendant -SO2F group. In some embodiments, reacting the second mixture comprises reacting the second mixture atFP0022-WG01 (45985-18) atmospheric pressure. In some embodiments, reacting the second mixture comprises reacting the second mixture at elevated pressure.

[0044] In some embodiments, reacting the second mixture comprises reacting the second mixture for a time in a range of from about 1 hour to about 24 hours. In some embodiments, reacting the second mixture comprises reacting the second mixture for a time in a range of from about 4 hours to about 12 hours.

[0045] Generally, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group formed in Step IV may be processed with any technique known in the art suitable to facilitate the method described herein. In some embodiments, the method further comprises processing the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group after reacting the second mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof.

[0046] In some embodiments, the method further comprises recovering the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group after reacting the second mixture.

[0047] In some embodiments, the ionomer comprising at least one pendant - SO3M group comprises at least one -COOM group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof. In some embodiments, the first mixture further comprises a further component comprising at least one -COOM group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof.

[0048] Generally, perfluorinated ionomers, ion exchange polymers, comprising perfluorinated sulfonic acids and / or perfluorinated sulfonate salts, such as PFSA ionomers, which are used in Step I, can be made by hydrolyzing precursor polymers containing -SO2F endgroups to give -SO3M endgroups. Where M is a cation other than H, the -SO3M endgroup may then optionally be treated with mineral acids to form -SO3H endgroups. Suitable precursor polymers containing sulfonyl fluoride endgroups 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 beFP0022-W001 (45985-18) 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.

[0049] Typically, the monomers containing at least one fluorinated sulfonyl fluoride functional group 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 independently H or F; and R1, R2, R3, R4, and R5are independently selected from H, F, Cl, or a perfluorinated or partially fluorinated alkyl or fluoroalkoxy group having 1 to 4 carbon atoms. For clarity, it is noted that the segment (CFR2)b- [O-(CFR3CFR4)c]a-O-(CFR5)dSC>2F 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.

[0050] In some embodiments, the precursor polymer containing sulfonyl fluoride endgroups is a copolymer made from one or more sulfonyl fluoride substituted monomers and one or more nonfunctionalized vinyl co-monomer(s). 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), C2F5OCF=CF2; and perfluoro(propyl vinyl ether), C3F7OCF=CF2) and and mixtures thereof. For example, the precursor polymer containing sulfonyl fluoride endgroups may be a copolymer of a sulfonyl fluoride-containing monomer with TFE, resulting inFP0022-W001 (45985-18) 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- 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.

[0051] 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.

[0052] 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.

[0053] 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-CF2CF2SC>2F. 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-CF2CF2SC>2F, 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 another salt form if desired for the particular application.

[0054] In some embodiments, the fluorinated sulfonyl fluoride ionomer precursor includes a perfluorocarbon backbone and a side chain represented by the formula -FP0022-W001 (45985-18)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-CF2CF2SC>2F, perfluoro(3 oxa-4-pentenesulfonyl fluoride) (PFSVE, also called short side-chain or SSC), followed by hydrolysis and conversion to the proton or salt form if desired for the particular application.

[0055] 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 another salt form if desired for the particular application.

[0056] 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, or N(R1)(R2)(R3)(R4), where R1, R2, R3, and R4are 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).

[0057] 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}- wherein b, c, a, d, R1, R2, R3, R4, and R5are as defined above and M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof, preferably H, Li, Na, K, Mg, Ca, or N(R1)(R2)(R3)(R4) where R1, R2, R3, and R4are 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 isFP0022-W001 (45985-18) the pendant chain from the perfluorinated polymer backbone. Branched pendant chains having multiple sulfonic acid groups are also encompassed.

[0058] Specific ion exchange polymer backbones may include side chains having one or more units represented by the following formulae:-[O-CF2CF(CF3)-O-(CF2)d-SO3M)]- and-[O-(CF2)d-SO3M)J- wherein d is 1-8, and M is H or an alkali metal.

[0059] 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]

[0060] In some embodiments the side chain in the fluorinated sulfonyl fluoride ionomer precursor may contain branched pendant chains bearing more than one sulfonyl fluoride group. After hydrolysis, the resulting fluorinated ionomer would contain branched pendant chains bearing more than one sulfonate group. For example in some embodiments, the repeating group can be represented by the formulaewherein Q1is a perfluoroalkylene group optionally having an etheric oxygen atom, Q2is a single bond or a perfluoroalkylene group optionally having an etheric oxygen atom, Rf3is a perfluoroalkyl group optionally having an etheric oxygen atom, X1is an oxygen atom, a nitrogen atom or a carbon atom, 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, ris 0 or 1, and M is selectedFP0022-W001 (45985-18) from H, alkali metals, alkaline-earth metals, and combinations thereof, preferably an alkali metal.

[0061] In other embodiments, the repeating group can be represented by the formulaewherein RF11is a single bond or a C1-6 linear perfluoroalkylene group which may have an etheric oxygen atom, and RF12is a C1-6 linear perfluoroalkylene group, ris 0 or 1 , and M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof, preferably an alkali metal. Fluorinated ionomers containing sulfonate or sulfonic acid groups of this type are disclosed in U.S. Patent No 7,531 ,610.

[0062] In some embodiments, the ionomer of the first mixture 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 fluorinated sulfonate or sulfonic acid groups. In some embodiments, the IXR of an ionomer 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 weight is given by the equation EW = (50 x IXR) + MWsc -19, where MWsc is the molecular weight of the side chain of the ionomer. As used herein, (EW) refers to the weight of the corresponding fluorinated sulfonic acid polymer in proton form required to neutralize one equivalent of NaOH, which can be measured by titration.

[0063] In one aspect, where the ionomer of the first mixture has one functional group, the ionomer 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 ionomer of the first mixture 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.FP0022-W001 (45985-18)

[0064] In one aspect, where the ionomer of the first mixture has more than one functional group, the ionomer has an IXR corresponding to the IXR of the preceding paragraph divided by the number of functional groups.

[0065] In one aspect, where the ionomer of the first mixture has two functional groups, the ionomer 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 ionomer of the first mixture 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.

[0066] In some embodiments, the ionomer of the first mixture 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 of the first mixture 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.

[0067] In one aspect, the ionomer of the first mixture contains the long side chain and has an EW less than about 1000; alternatively less than about 980; alternatively less than about 950; alternatively less than about 930, or any value, range, or subrange therebetween. In one aspect, the fluorinated sulfonyl fluoride polymer and its corresponding fluorinated sulfonate or sulfonic acid polymer has an EW of at least about 700; alternatively, at least about 750; alternatively, at least about 800; alternatively at least about 950, or any value, range, or sub-range therebetween. The IXR for a fluorinated polymer with the side chain -O-CF2-CF(CF3)-O-CF2-CF2-SC>3H, i.e., produced from a copolymer of TFE and PSEPVE, can be related to EW using the following formula: 50 IXR + 344 = EW.

[0068] In another embodiment, the fluorinated sulfonyl fluoride polymer and its corresponding fluorinated sulfonate or sulfonic acid polymer contains the short side chain and has an EW less than about 840; alternatively less than about 810; alternatively less than about 785; alternatively less than about 765, or any value, range, or sub-range therebetween. In one aspect, the fluorinated sulfonyl fluoride polymer and its corresponding fluorinated sulfonate or sulfonic acid polymer has anFP0022-W001 (45985-18)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. 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.

[0069] In some embodiments, the ionomer of the first mixture may further include one or more functional groups to improve ionic conductivity, water uptake, chemical stability, and / or mechanical properties. In some embodiments, the ionomer of the first mixture is a cationic exchange polymer comprising a functional group selected from the group consisting of sulfonate, phosphate, and carboxylate and derivatives thereof, and combinations thereof.

[0070] In many embodiments, a product includes a sulfonyl fluoride-containing polymer produced according to a method including (i) at least partially chlorinating an at least partially hydrolyzed ionomer to produce an at least partially chlorinated ionomer and (ii) at least partially fluorinating the at least partially chlorinated ionomer to produce the sulfonyl fluoride-containing polymer .

[0071] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group may also contain -SO3H groups or unreacted - SO2CI groups. If desired, this material may be combined with the first mixture and cycled through the chlorination and fluorination methods of steps II and IV to provide a sulfonyl fluoride-containing polymer comprising additional pendant -SO2F groups.

[0072] In some embodiments, the ionomer of the first mixture comprising at least one pendant -SO3M group is pre-processed to be in a form suitable for reaction. In some embodiments, the ionomer comprising at least one pendant -SO3M group is pre-processed to have a particle size suitable for reaction. For example, the ionomer comprising at least one pendant -SO3M group may be dispersed according to conventional means and then spray-dried to form particles of ionomer comprising at least one -SO3M group.

[0073] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is isolated and melt extruded to provide a pellet, tube, rod, or film.FP0022-W001 (45985-18)

[0074] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is isolated and contacted with fluorine gas (F2) to remove unwanted and reactive endgroups from the polymer.

[0075] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is isolated and contacted with fluorine gas (F2) and then melt extruded to provide a pellet, tube, rod, or film.

[0076] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is isolated and melt extruded to provide a pellet, tube, rod, or film and then contacted with fluorine gas (F2) to remove unwanted and reactive endgroups from the polymer.

[0077] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is isolated and melt extruded to provide a pellet, tube, rod, or film and contacted with fluorine gas (F2) during the extrusion process to remove unwanted and reactive endgroups from the polymer.

[0078] In some embodiments, the method further comprises converting the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group to a further ionomer comprising at least one -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof.

[0079] The sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group, whether contacted with F2 gas or not, may subsequently be converted to a further ionomer having at least one -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof. The sulfonyl fluoride- containing polymer may be hydrolyzed in an aqueous alkali metal hydroxide solution to convert the sulfonyl fluoride groups to sulfonate groups. The sulfonate groups may be acidified by an acid, such as nitric acid, to form sulfonic acid endgroups. Alkali metal hydroxides include but are not limited to NaOH or KOH. During the hydrolysis step, a water-soluble organic solvent may be employed in the hydrolysis solution, such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide, N,N- dimethylacetamide, N-methyl-2-pyrrolidinone, N-ethyl-2-pyrrolidone, methanol, ethanol, isopropanol, butanol, methoxyethoxyethanol, butoxyethanol, butylcarbitol, hexyloxyethanol, octanol, propylene glycol methyl ether, ethylene glycol, ethanolamine, N-methylethanolamine, N-ethylethanolamine, 1-amino-2-propanol, 1-FP0022-W001 (45985-18) amino-3-propanol, 2-aminoethoxyethanol, 2-aminoethoxyethanol, and 2-amino-2- methyl-1-propanol.

[0080] In many embodiments, a product includes the further ionomer comprising at least one -SO3M group produced according to the method of the present disclosure.

[0081] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is converted into a further ionomer having at least one -SO3M group and is used in a product 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.

[0082] In some embodiments, the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group is optionally reacted with elemental fluorine and / or extruded and is utilized in an application selected from a fuel cell membrane, a water electrolysis membrane, a chloro-alkali electrolysis cell, a redox flow battery, a humidifier, a dehumidifier, an ion exchange product, a filtration product, a deacidification product, a catalyst application, and combinations thereof.

[0083] Further aspects of the present disclosure are provided by the subject matter of the following clauses:

[0084] 1. A method comprising:I) forming a first mixture comprising: a) an ionomer comprising at least one pendant -SO3M group, wherein M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof; b) a chlorination reagent; and c) a chlorination solvent;II) reacting the first mixture to produce an at least partially chlorinated ionomer comprising at least one pendant -SO2CI group;III) forming a second mixture comprising: a) the ionomer comprising at least one pendant -SO2CI group; b) a fluorination reagent; andFP0022-W001 (45985-18) c) optionally a fluorination solvent; andIV) reacting the second mixture to produce a sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group.

[0085] 2. The method of the preceding clause, wherein the ionomer comprising at least one pendant -SO3M group is selected from perfluorosulfonic acid ionomers, at least partially fluorinated sulfonic acid ionomers, and combinations thereof.

[0086] 3. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group is in a form selected from films, sheets, rolls, membranes, pellets, extrudates, particles, spray-dried particles, chips, flakes, powders, and combinations thereof.

[0087] 4. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group is obtained from new ionomers, used ionomers, waste ionomers, or recycled ionomers, and combinations thereof.

[0088] 5. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm.

[0089] 6. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group has an equivalent weight in a range of from about 800 to about 1500.

[0090] 7. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group has an ion exchange ratio in a range of from about 3.55 to about 13.2.

[0091] 8. The method of any preceding clause, wherein the chlorination reagent is selected from phosphorus(V) chlorination reagents, phosphorus(V) chlorination reagents generated in situ by reaction of chlorine and phosphorus(lll) precursor reagents RPCI2, wherein R is selected from Cl, alkyl, haloalkyl, aryl, and combinations thereof, phenyldichlorophosphine, and combinations thereof

[0092] 9. The method of any preceding clause, wherein the chlorination solvent is inert to CI2 and strong Lewis acids and has a boiling point greater than about 80°C.FP0022-W001 (45985-18)

[0093] 10. The method of any preceding clause, where in the chlorination solvent is selected from halogenated arenes, trifl uoromethyl-substituted arenes, trifl uoromethyl-substituted halogenated arenes, and combinations thereof.

[0094] 11 . The method of any preceding clause, wherein the chlorination solvent is selected from chlorobenzene, fluorobenzene, difluorobenzene, 1 ,2- dichlorobenzene, 1 ,2,4-trichlorobenzene, benzotrifluoride, hexafluoro-m-xylene, 4- chlorobenzotrifluoride, 2-chlorobenzotrifluoride, 2,4-dichlorobenzotrifluoride, 3,4- dichlorobenzotrifluoride, and combinations thereof.

[0095] 12. The method of any preceding clause, wherein reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 80 °C to about 150 °C.

[0096] 13. The method of any preceding clause, wherein reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 100 °C to about 135 °C.

[0097] 14. The method of any preceding clause, wherein reacting the first mixture comprises reacting the first mixture at atmospheric pressure.

[0098] 15. The method of any preceding clause, wherein reacting the first mixture comprises reacting the first mixture for a time in a range of from about 1 hour to about 24 hours.

[0099] 16. The method of any preceding clause, further comprising processing the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof.

[0100] 17. The method of any preceding clause, further comprising recovering the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture.

[0101] 18. The method of any preceding clause, wherein the fluorination reagent is selected from alkali metal fluorides.FP0022-W001 (45985-18)

[0102] 19. The method of any preceding clause, wherein the fluorination reagent is selected from lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, and combinations thereof.

[0103] 20. The method of any preceding clause, wherein the fluorination solvent is selected from anhydrous polar aprotic organic solvents.

[0104] 21. The method of any preceding clause, wherein the fluorination solvent is selected from nitriles, carboxylic amides, heterocyclic amides, sulfoxides and sulfones, and combinations thereof.

[0105] 22. The method of any preceding clause, wherein the fluorination solvent is selected from acetonitrile, butyronitrile, benzonitrile, N,N-dimethylformamide, dimethylacetamide, N-methyl formamide, formamide, 1 ,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, tetramethylene sulfone, and combinations thereof.

[0106] 23. The method of any preceding clause, wherein reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 25 °C to about 120 °C.

[0107] 24. The method of any preceding clause, wherein reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 40 °C to about 100 °C.

[0108] 25. The method of any preceding clause, wherein reacting the second mixture comprises reacting the second mixture for a time in a range of from about 1 hour to about 24 hours.

[0109] 26. The method of any preceding clause, further comprising processing the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group after reacting the second mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof.

[0110] 27. The method of any preceding clause, further comprising recovering the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group after reacting the second mixture.FP0022-W001 (45985-18)

[0111] 28. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group comprises at least one -COOH group.

[0112] 29. The method of any preceding clause, wherein the first mixture further comprises a further component comprising at least one -COOH group.

[0113] 30. The method of any preceding clause, wherein the alkali metals are selected from Li, Na, K, Rb, Cs, and combinations thereof

[0114] 31 . The method of any preceding clause, wherein the alkaline-earth metals are selected from Mg, Ca, Sr, Ba, and combinations thereof.

[0115] 32. The method of any preceding clause, further comprising the step of drying the ionomer comprising at least one pendant -SO3M group prior to forming the first mixture.

[0116] 33. The method of any preceding clause, where the drying step is conducted at a temperature of about 40 °C to about 130 °C.

[0117] 34. The method of any preceding clause, where the drying step is conducted at a temperature of about 40 °C to about 110 °C.

[0118] 35. The method of any preceding clause, where the drying step is conducted at a reduced pressure of about 0.006 kPa to about 70.9 kPa.

[0119] 36. The method of any preceding clause, where the drying step is conducted at a reduced pressure of about 10.1 kPa to about 70.7 kPa.

[0120] 37. The method of any preceding clause, where the ionomer comprising at least one pendant -SO3M group has a water content below about 6 weight percent, based on the total weight of the ionomer.

[0121] 38. The method of any preceding clause, where the ionomer comprising at least one pendant -SO3M group has a water content below about 1 weight percent, based on the total weight of the ionomer.

[0122] 39. The method of any preceding clause, wherein the ionomer comprising at least one pendant -SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm.FP0022-W001 (45985-18)

[0123] 40. The method of any preceding clause, further comprising reducing the particle size of the ionomer comprising at least one pendant -SO3M group before step I.

[0124] 41. The method of any preceding clause, wherein the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm.

[0125] 42. The method of any preceding clause, wherein the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm.

[0126] 43. The method of any preceding clause, further comprising reducing the particle size of the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group before step III.

[0127] 44. A sulfonyl fluoride-containing polymer comprising at least one pendant-SO2F group produced according to the method of any preceding clause.

[0128] 45. The method of any preceding clause, further comprising converting the sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group to a further ionomer comprising at least one -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof.

[0129] 46. An ionomer comprising at least one -SO3M group produced according to the method of the preceding clause.

[0130] 47. A membrane comprising the ionomer comprising at least one -SO3M group produced according the method of any preceding clause.

[0131] 48. A product comprising the ionomer comprising at least one -SO3M group of any preceding clause.

[0132] 49. 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 usedFP0022-W001 (45985-18) in filtration applications, products used in deacidification applications, products used in catalysis applications, and combinations thereof.EXAMPLES

[0133] 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 value and the highest value enumerated are to be considered to be expressly stated in this application.

[0134] The particle size D50 was measured by dry laser diffraction (Microtac S3500 particle size analyzer with Turbotrac dry powder dispensing unit).

[0135] Example 1 . Spray-dried PFSA 920EW (H+ form) converted to -SO2CI form using PhPCL in CBTF (two passes).

[0136] A 300 mL three neck flask containing a PTFE-coated stirring bar was charged with 12.235 g of spray-dried CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O- CF2CF2SO3H PFSA copolymer having an EW of 920 and a particle size of 23 pm. The ionomer was dried under vacuum at a pressure of about 40.4 kPa and a temperature of about 76 °C for about 17 h. The flask was then charged with 4- chlorobenzotrifluoride (94.3 g) and P,P-dichlorophenylphosphine (8.5 mL, ca. 63 mmoles). Chlorine gas (ca. 79 mmoles) was admitted to the flask over the course of 0.8 hour; the temperature in the flask increased from about 24 °C to 41 °C during this time. The chlorinated mixture was heated at 99-105 °C for 5 hours. After cooling, the polymer product was recovered by filtration. After washing sequentially with toluene, acetone, methanol, water, methanol, and acetone and drying under vacuum,FP0022-W001 (45985-18)ATR-IR analysis indicated the presence of unconverted RfSOsH groups based on the presence of a band at about 1055 cm-1.

[0137] The at least partially chlorinated ionomer (9.897 g) was returned to the flask along with 4-chlorobenzotrifluoride (121.4 g) and P,P-dichlorophenylphosphine (8.5 mL, ca. 63 mmoles). The mixture was treated with chlorine gas followed by heating at 99-107 °C for 4.5 hours. The reaction was filtered and the recovered polymer was washed as before and dried under vacuum to give 8.789 g of PFSA polymer in the sulfonyl chloride form as indicated by an I R peak at 1427 cm-1and the absence of a peak for a sulfonate group at approximately 1055 cm-1.

[0138] Example 2. Spray-dried PFSA 920EW (K+ form) reacted with PhPCk in CBTF with high conversion after three passes.

[0139] Spray-dried CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO3K PFSA copolymer (7.64 g) having an EW of 920 and a particle size of 10 pm was dried in a vacuum oven at about 104 °C at a pressure of about 40.4 kPa for 21 hours. The dried ionomer was then the mixed with P,P-dichlorophenylphosphine (7.68 g, 42.9 mmoles) in 4-chlorobenzotrifluoride (93.9 g). The mixture was chlorinated and then stirred for 5 hours at 100-109 °C. The polymer product was isolated by filtration followed by washing with toluene, acetone, and methanol and vacuum drying to give 7.279 g of white solid. ATR-IR analysis showed a weak band at 1425 cm-1and a peak at 1057 cm-1indicating partial conversion of the -SOsK endgroups to -SO2CI endgroups.

[0140] The product was re-treated with 49.4 mmoles of P,P- dichlorophenylphosphine in 4-chlorobenzotrifluoride (82.3 g) followed by chlorination and heating at 101-112 °C for 6 hours. ATR-IR analysis indicated an increased conversion of the -SO3K endgroups to -SO2CI endgroups based on an increase in intensity of the 1425 cm-1band and a reduced intensity of the 1057 cm-1band.

[0141] The product was suspended in 4-chlorobenzotrifluoride (88.0 g) and then phenylphosphonic dichloride (36.2 mmoles) was added followed by heating for 3 hours at 71-85 °C. P,P-dichlorophenylphosphine (31.7 mmoles) was then added to the mixture followed by chlorination and heating at 118-130 °C for 7 hours. ATR-IRFP0022-W001 (45985-18) analysis of the product indicated the presence of -SO2CI endgroups; the absence of a band at about 1056 cm-1confirmed high conversion of the sulfonic acid endgroups.

[0142] Example 3. Spray-dried PFSA 920EW (H+ form) pre-treated with P(O)Cls in CBTF followed by reaction with PCI5 gave low conversion to -SO2CI form.

[0143] A 250 mL three neck flask containing a PTFE-coated stirring bar was charged with 7.70 g of spray-dried CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO3H PFSA copolymer having an EW of 920 and a particle size of 23 pm; the ionomer was dried under vacuum at a pressure of about 40.4 kPa and a temperature of about 106 °C for 4.5 h. The flask was then charged with 4-chlorobenzotrifluoride (90.8 g) and phosphorous oxytrichloride (3.56 g, 23.2 mmoles) and the mixture stirred at 90 to 104 °C for 2.5 hours. The resulting mixture was stirred overnight at room temperature and then treated with phosphorus trichloride (4.3 g, 31 .3 mmoles) followed by chlorination. The chlorinated mixture was then stirred at 99-106 °C for 5.6 hours. After cooling, the reaction mixture was quenched with water and filtered. The product was washed with acetone, methanol, water and again with acetone and dried under vacuum to give 6.64 g of off white powder. ATR-IR analysis indicated some conversion of the - SO3H endgroups to -SO2CI endgroups based on a weak band at 1428 cm-1and a strong band at 1061 cm-1.

[0144] Example 4. Spray-dried PFSA 920EW (H+ form) pre-treated with PhP(O)Cl2 in CBTF followed by reaction with PhPCU converted -SO3H to -SO2CI form.

[0145] A 300 mL three neck flask containing a PTFE-coated stirring bar was charged with 6.75 g of spray-dried CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O-CF2CF2SC>3H PFSA copolymer having an EW of 920 and a particle size of 23 pm; the ionomer was dried under vacuum at a pressure of about 40.4 kPa and a temperature of about 102 °C for 3.2 h. The flask was then charged with 4-chlorobenzotrifluoride (77.2 g) and P,P-dichlorophenylphosphine oxide (4.2 g, 29.9 mmoles) and the mixture stirred at 72 to 82°C for 3 hours. After cooling to room temperature, P,P- dichlorophenylphosphine (5.35 g, 42.9 mmoles) was added to the flask followed by addition of an excess of chlorine gas over the course of 0.5 h at 22-36 °C. The chlorinated mixture was then stirred at 104-111°C for 6.5 hours. After cooling, the reaction mixture was filtered, and the product washed with toluene, acetone, methanol, and water and dried under vacuum to give 5.919 g of white solid. ATR-IRFP0022-W001 (45985-18) analysis showed a strong band at 1426 cm-1and no evidence of sulfonate endgroups indicating complete conversion of the -SO3H endgroups to -SO2CI endgroups.

[0146] Example 5. Spray-dried PFSA 920EW (H+ form) pre-treated with PhP(O)Ch in ODCB followed by reaction with PhPCk

[0147] Spray-dried CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO3H PFSA copolymer (6.63 g) having an EW of 920 and a particle size of 23 pm was oven-dried at a temperature of about 105 °C and a pressure of about 40.4 kPa for 2.5 hours. The ionomer was mixed with P,P-dichlorophenylphosphine oxide (4.61 g, 23.6 mmoles) in 1 ,2-dichlorobenzene (74.6 g) for 3 hours at 75-88 °C. After addition of P,P- dichlorophenylphosphine (3.69 g, 20.6 mmoles) followed by chlorination, the resulting reaction mixture was stirred at 98-107 °C for 6 hours. After cooling, filtration of the reaction mixture followed by washing, and vacuum-drying gave white solid product (5.809 g). ATR-IR analysis indicated complete conversion of the -SO3H endgroups to -SO2CI endgroups; no evidence of sulfonate endgroups was observed.

[0148] Example 6. Good conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMF at 70°C for 5 h.

[0149] A 1.3223-g sample of chlorinated spray-dried 920EW PFSA powder from Example 1 was stirred with potassium fluoride (1.517 g, 26.1 mmoles) in N,N- dimethylformamide (36.609 g) for 5 hours at 70° C. After cooling, the fluorinated spray-dried 920 EW PFSA powder was filtered, and the polymer washed with water and acetone to remove excess KF. The isolated polymer was then dried under full vacuum at 85 °C. After isolation, the ATR-IR spectrum indicated complete conversion of the -SO2CI endgroups to -SO2F endgroups based on the strong band at 1467 cm’1and absence of a band at 1426 cm’1; a small amount of hydrolysis was observed based on a weak band in the IR at 1059 cm’1. The19F magic angle spinning NMR spectrum indicated the sample was over 60% in the -SO2F form based on a chemical shift of -112 ppm for the CF2 group bonded to the -SO2F endgroup and a resonance at +44 ppm for the fluorine in the SO2F group.

[0150] Example 7. Partial conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in sulfolane at 100°C for 3 h.

[0151] A 0.2696-g sample of chlorinated spray-dried 920EW PFSA powder from Example 1 was stirred with potassium fluoride (0.2696 g, 4.6 mmoles) inFP0022-W001 (45985-18) tetramethylene sulfone (20 mL) for 3 hours at 100°C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated partial conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis.

[0152] Example 8. Complete conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMF at 60°C for 4 h.

[0153] A 0.145-g sample of chlorinated spray-dried 920EW PFSA powder from Example 1 was stirred with potassium fluoride (0.1807 g, 3.11 mmoles) in N,N- dimethylformamide (9.44 g) for 4 hours at 60 °C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated complete conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis. This was confirmed by a transmission IR spectrum which showed only a weak band corresponding to -SO2CI endgroups.

[0154] Example 9. Complete conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMSO at 60°C for 3.5 h.

[0155] A 0.2617-g sample of chlorinated spray-dried 920EW PFSA powder prepared by a two-fold scale-up of the procedure in Example 1 was stirred with potassium fluoride (0.1759 g, 3.03 mmoles) in dimethyl sulfoxide (13.89 g) for 3.5 hours at 60 °C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated complete conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis. This was confirmed by a transmission IR spectrum which showed only a weak band corresponding to -SO2CI endgroups.

[0156] Example 10. High conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in N-methylformamide at 50°C for 3 h.

[0157] A 0.2741 -g sample of chlorinated spray-dried 920EW PFSA powder prepared by a two-fold scale-up of the procedure in Example 1 was stirred with potassium fluoride (0.1324 g, 2.28 mmoles) in N-methylformamide (12.532 g) for 3 hours at 50 °C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. TheFP0022-W001 (45985-18)ATR-IR spectrum indicated complete conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis. This was confirmed by a transmission IR spectrum which showed only a weak band corresponding to -SO2CI endgroups.

[0158] Example 11. High conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMSO at 60 °C overnight.

[0159] A 5.071-g sample of chlorinated spray-dried 920EW PFSA powder from Example 4 was stirred with potassium fluoride (2.507 g, 43.15 mmoles) in dimethyl sulfoxide (86.47 g) overnight at 60 °C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated complete conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis. The19F magic angle spinning NMR spectrum indicated the sample was over 80% in the -SO2F form based on a chemical shift of -112 ppm for the CF2 group bonded to the -SO2F endgroup and a resonance at +44 ppm for the fluorine in the SO2F group.

[0160] Example 12. High conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMSO at 60°C.

[0161] A 3.165-g sample of spray-dried 920EW PFSA powder, containing a mixture of -SO2F and SO2CI endgroups and a small amount of unconverted -SO3H endgroups, was stirred with potassium fluoride (1.39 g, 23.93 mmoles) in dimethyl sulfoxide (81.21 g) for 3 hours at 60 °C. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated complete conversion of the - SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis. The19F magic angle spinning NMR spectrum indicated that over 95% of the sample was in the -SO2F form based on a chemical shift of -112 ppm for the CF2 group bonded to the -SO2F endgroup and a resonance at +44 ppm for the fluorine in the SO2F group.

[0162] Example 13. Milled 1000EW PFSA (H+ form) with PhPCI4in CBTF converted -SO3H to -SO2CI form.

[0163] A 250-mL three neck flask equipped with a thermocouple well and a condenser topped with nitrogen bubbler was charged with 4-chlorobenzotrifluoride (67.6 g) and P,P-dichlorophenylphosphine (6.63 g, 37.0 mmoles). A gas inlet tube was placed in a side neck of the flask, and excess chlorine gas flowed to the flaskFP0022-W001 (45985-18) over the course of 0.9 hour. The temperature in the flask increased from about 23 °C to 37°C during this time. After cooling, a sample of 1000EW CF2=CF2 / CF2=CF-O- CF2CF(CF3)-O-CF2CF2SC>3H PFSA copolymer (H+ form, 5.266 g), shredded and then milled in an Ika T25 Ultra Turrax™ homogenizer in a mixture of ethanol and water to approximately 2 mm2pieces, was added to the flask. The mixture was heated for 3 hours at 100-108 °C. After cooling the reaction mixture was filtered, and the recovered polymer was washed with 4-chlorobenzotrifluoride and hexane, then dried under vacuum to give 5.201 g of product. Analysis by ATR-IR indicated the presence of unconverted -SOsH groups as shown by a peak at about 1050 cm-1.

[0164] The product was re-chlorinated in 4-chlorobenzotrifluoride (67.6 g) with P,P-dichlorophenylphosphine (3 g, 16.9 mmoles) followed by treatment with chlorine gas and heating at 90-93 °C for 4 hours. After cooling, the reaction mixture was filtered and the recovered polymer was washed with 4-chlorobenzotrifluoride and hexane, then dried under vacuum to give 4.507 g of product. Analysis by ATR-IR and transmission IR indicated complete conversion of the ionomer form to the -SO2CI form which is characterized by a band at about 1430 cm-1. The magic angle spinning (MAS)19F NMR shows a peak at -109 ppm assigned to the CF2 group bonded to the -SO2CI endgroup.

[0165] Example 14. Milled 1000EW PFSA (H+ form) with PhPCI4in CBTF converted -SO3H to -SO2CI form.

[0166] A sample of 1000EW CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O-CF2CF2SO3H PFSA copolymer (H+ form), shredded and then milled in an Ika T25 Ultra Turrax™ homogenizer in a mixture of ethanol and water to approximately 2 mm2pieces. The resulting pieces were dried under vacuum overnight at 54 °C and then weighed into a 250-mL flask (5.825 g) and dried under vacuum for approximately 19 hours at about 74 °C. After cooling, the flask was equipped a thermocouple well and a condenser topped with a nitrogen bubbler. The flask was then charged with 4- chlorobenzotrifluoride (67.6 g) and P,P-dichlorophenylphosphine (4.04 g, 22.6 mmoles). A gas inlet tube was placed in a side neck of the flask, and chlorine gas (ca. 32 mmoles) was admitted to the flask over the course of 0.5 hour; the temperature in the flask increased from about 23 °C to 32 °C during this time. After purging excess chlorine from the flask, the gas inlet was replaced with a glass stopper and the yellow mixture was heated at 92-101 °C for 5 hours. After cooling the reaction mixture wasFP0022-W001 (45985-18) filtered and the recovered polymer washed with 4-chlorobenzotrifluoride, toluene, and hexane and then dried under vacuum. Analysis by ATR-IR indicated complete conversion of the ionomer to the -SO2CI form as shown by a peak at 1426 cm-1in the infra-red spectrum; hydrolysis was not observed based on the absence of a band in the IR around 1050 cm-1.

[0167] Example 15. Chopped 1000EW PFSA (Na+ form) with PhPCI4in CBTF converted -SO3H to -SO2CI form.

[0168] A sample of chopped 1000EW CF2=CF2 / CF2=CF-O-CF2CF(CF3)-O- CF2CF2SO3H PFSA copolymer in the Na+ form was prepared by treating the H+ form of the chopped polymer (ca. 9 mm2pieces) with excess of 6.7 weight % aqueous NaOH at 60 °C followed by water-washing and drying. The chopped ionomer (10.832 g) was weighed into a 500-mL flask and dried under vacuum for approximately 30 hours at about 78-80 °C. After cooling, the flask was equipped with a thermocouple well and a condenser topped with a nitrogen bubbler. The flask was then charged with 4-chlorobenzotrifluoride (162.3 g) and P,P-dichlorophenylphosphine (8.57 g, 47.9 mmoles). Chlorine gas (72 mmols) was added to the flask at 22-32 °C followed by a heating for 5.5 hours at 95-103 °C. After cooling, the reaction mixture was filtered and the recovered polymer was washed with toluene, methanol, water, and acetone followed by vacuum drying. Analysis by ATR-IR indicated complete conversion of the ionomer to the -SO2CI form of the polymer.

[0169] Example 16. Conversion of chlorinated 1000EW PFSA to -SO2F form using CsF in acetonitrile.

[0170] A vial containing a PTFE-coated stir bar was charged with sieve-dried acetonitrile (10 mL, 7.83 g) and dry cesium fluoride (0.255 g, 1.68 mmoles). The mixture was stirred for 10 minutes and then a sample of chlorinated ionomer from Example 13 (0.3 g) was then added to the vial. The vial was sealed and stirred vigorously for 120 hours at room temperature. The mixture was filtered and the polymer washed three times with 5-mL portions of methanol. Analysis by ATR-IR indicated that sulfonyl chloride groups were still present (peak at 1427 cm-1), but aFP0022-W001 (45985-18) small peak at 1467 cm-1indicated some conversion to the sulfonyl fluoride form of the polymer.

[0171] Example 17. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in DMF and water.

[0172] A vial containing a PTFE-coated stir bar was charged with a sample of chlorinated ionomer from Example 13 (0.414 g), potassium fluoride (0.5052 g), Aliquat™ 336 (0.1626 g), N,N-dimethylformamide (3 mL), and water (3 mL). The mixture was allowed to stir overnight. A sample was taken from mixture, washed with water, and dried under vacuum. Analysis by ATR-IR indicated that sulfonyl chloride groups were still present, but a small peak for the sulfonyl fluoride form of the polymer as well as a small peak corresponding the sulfonate end group indicative of hydrolysis indicated conversion.

[0173] Example 18. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in tetramethylene sulfone.

[0174] A sample of chlorinated ionomer from Example 14 (0.2874 g) was stirred with potassium fluoride (0.1841 g) in tetramethylene sulfone (18 g) for 28 hours at 80 °C. After 2 hours, significant conversion of the sulfonyl chloride endgroups to the sulfonyl fluoride endgroups had occurred.

[0175] Example 19. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in DMSO.

[0176] A sample of chlorinated ionomer from Example 14 (0.1797 g) was stirred with potassium fluoride (0.28 g) in dimethyl sulfoxide (15 mL) at 80 °C. After 3 hours, dimethyl sulfoxide was decanted and the polymer was dried under full vacuum at 60 °C. The dried polymer was washed with water and acetone and redried under vacuum at 60 °C. Analysis of the dried polymer by ATR-IR indicated conversion of the endgroups to SO2F based on the band in the IR spectrum at 1467 cm-1with only small amounts of unreacted SO2CI endgroups (1426 cm-1) and hydrolysis product (weak band at 1057 cm-1).

[0177] Example 20. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in DMF.

[0178] A sample of chlorinated ionomer from Example 15 (1.0092 g) was stirred with potassium fluoride (1.024 g, 17.6 mmoles) in N,N-dimethylformamide (14.324 g)FP0022-W001 (45985-18) for 4.25 h at 60 °C. After cooling to room temperature, the reaction mixture was filtered and the polymer was washed with water and acetone followed by vacuum drying at 85 °C for 3 hours. The ATR-IR of the recovered polymer indicated incomplete conversion of the -SO2CI groups to -SO2F groups. The polymer was re-treated with potassium fluoride (0.9929 g, 17.1 mmoles) and N,N-dimethylformamide (12.183 g) for 4.5 h at 60 °C. After isolation, the ATR-IR spectrum indicated complete conversion.19F magic angle spinning NMR suggested the sample was approximately 30% in the -SO2F form and 70% in the -SO2CI form based on integration of the -SO2F peak at +44 ppm in the19F NMR spectrum as compared with the other side chain resonances. The combination of ATR-IR and NMR data suggest that the conversion to -SO2F may be more focused on the surface and underlying regions, such that the entirety of the material is approximately 30% in the -SO2F form.

[0179] Example 21. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in DMF.

[0180] A 1.0092-g sample of chopped 1000EW CF2=CF2 / CF2=CFOCF2CF(CF3)OCF2CF2SC>3Na PFSA co-polymer film that had been chlorinated to -SO2CI endgroups was cryoground to a powder and dried under vacuum. The ground film was stirred in a mixture of potassium fluoride (1.024 g, 17.63 mmoles) in N, N-dimethylformamide (15 mL) for 4.5 hours at 60 °C. After cooling to room temperature, the product mixture was filtered and washed with water and acetone followed by vacuum drying. The ATR-IR spectrum showed partial conversion of the endgroups based on the appearance of IR bands at 1470cm-1and 1427 cm-1. The partially fluorinated material (1.0092 g) was returned to the flask along with N, N-dimethylformamide (15 mL) and potassium fluoride (0.9929 g, 17.09 mmoles) and stirred for 4.5 hours at 60 °C. After cooling to room temperature, the product mixture was filtered and washed with water and acetone and dried by vacuum drying. The ATR-IR spectrum showed full conversion of the -SO2CI endgroups to - SO2F endgroups; a small amount of hydrolysis was indicated by a weak IR band at 1062cm-1.19F MAS NMR shows sulfonyl fluoride accounts for 30% of the PSEPVE present in the polymer and the remaining 70% is sulfonyl chloride. The combination of ATR-IR and NMR data suggest that the conversion to -SO2F may be more focusedFP0022-W001 (45985-18) on the surface and underlying regions, such that the entirety of the material is approximately 30% in the -SO2F form.

[0181] Example 22. Conversion of chlorinated 1000EW PFSA to -SO2F form using KF in DMF.

[0182] A 0.178-g sample of chopped 1000EW CF2=CF2 / CF2=CFOCF2CF(CF3)OCF2CF2SC>3H PFSA co-polymer film that had been chlorinated to -SO2CI endgroups was stirred with potassium fluoride (0.189 g, 3.25 mmoles) in N, N-dimethylformamide (5 mL) for 16 hours at 50 °C. After cooling to room temperature, the product mixture was filtered and washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated partial conversion of the -SO2CI endgroups to -SO2F endgroups with a small amount of hydrolysis indicated by a week IR band at 1059cm'1.

[0183] Example 23. Spray-dried PFSA 920EW (H+ form) pre-treated with PhP(O)Cl2 in 1 ,2-dichlorobenzene followed by reaction with PhPCk

[0184] A sample of spray-dried CF2=CF2 / CF2=CFOCF2CF(CF3)OCF2CF2SO3H PFSA co-polymer 920EW was dried in a vacuum oven at 100-108 °C for about 2 hours at a pressure of about 40 kPa. A portion of this material (10.005 g) was transferred to a 500-mL three-neck flask containing a PTFE-coated stirring bar. The flask was held under dynamic vacuum (ca. 0.013 kPa) at 41 -87 °C for about 1.2 hours. The flask was then filled with nitrogen and charged with 1 ,2-dichlorobenzene (188.1 g) followed by P,P-dichlorophenylphosphine oxide (4.97 g, 25.49 mmoles). The mixture was heated at 87-90 °C for 3 hours. P,P-dichlorophenylphosphine (5.66 g, 31 .62 mmoles) was then added to the flask. The mixture was then treated with an excess of chlorine gas over the course of 34 minutes at a temperature of 20.4°C to 32.7 °C. The chlorinated mixture was then warmed to 101-114°C for 5 hours. After cooling, the reaction mixture was filtered. The chlorinated polymer was washed sequentially with toluene, acetone, methanol, water, and acetone and then dried under dynamic vacuum at room temperature. ATR-IR analysis showed a strong bandFP0022-W001 (45985-18) at 1425.7 cm-1and a very weak band at about 1055 cm-1indicating high conversion of the -SO3H endgroups to -SO2CI endgroups.

[0185] Example 24. Spray-dried PFSA 920EW (H+ form) pre-treated with PhP(O)Ch in 1 ,2-dichlorobenzene followed by two treatments with PhPCk

[0186] A sample of spray-dried CF2=CF2 / CF2=CFOCF2CF(CF3)OCF2CF2SO3H PFSA co-polymer 920EW was dried in a vacuum oven at 106-112 °C for about 2 hours at a pressure of about 40 kPa. A portion of this material (11.292 g) was transferred to a 500 mL three neck flask containing a PTFE-coated stirring bar. The flask was held under dynamic vacuum (ca. 0.010 kPa) at 80-82 °C for about 1 hour. The flask was then filled with nitrogen and charged with 1 ,2-dichlorobenzene (181.8 g) followed by P,P-dichlorophenylphosphine oxide (7.38 g, 37.85 mmoles). The mixture was heated at 78-92°C for 2 hours. P,P-dichlorophenylphosphine (5.46 g, 30.51 mmoles) was then added to the flask. The mixture was then treated with an excess of chlorine gas over the course of 40 minutes at a temperature of 18.8 °C to 29.4 °C. The chlorinated mixture was then warmed to 101-111 °C for 5 hours. After cooling, the reaction mixture was filtered. The chlorinated polymer was washed sequentially with toluene, acetone, methanol, water, and acetone and then dried under dynamic vacuum at room temperature. The isolated polymer was returned to the reaction flask along with 1 ,2-dichlorobenzene (207.2 g) followed by P,P- dichlorophenylphosphine (4.77 g, 26.7 mmoles). The mixture was then treated with an excess of chlorine gas over the course of 25 minutes at a temperature of 23.5 °C to 31 .8 °C. The chlorinated mixture was then warmed to 102-110 °C for 4 hours. After cooling, filtering, washing, and drying under vacuum, the isolated polymer was analyzed by ATR-IR. A strong band at 1425.6 cm-1was observed; no peak corresponding to the sulfonate endgroup was detected.

[0187] Example 25. High conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMSO at 60°C.

[0188] A 7.8730-g sample of chlorinated spray-dried 920EW PFSA powder from Example 24 was stirred with potassium fluoride (3.69 g, 63.51 mmoles) in dimethyl sulfoxide (140.67 g) at 60 °C for 3 hours. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum indicated conversion of the -SO2CIFP0022-W001 (45985-18) endgroups to -SO2F endgroups was not complete. The partially fluorinated spray- dried 920EW PFSA powder was stirred with additional potassium fluoride (1.220 g, 20.998 mmoles) in dimethyl sulfoxide (62.649 g) at 60 °C for 2 hours. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum had a strong band at 1466.1 cm-1indicating complete conversion of the -SO2CI endgroups to -SO2F endgroups; a small amount of hydrolysis had occurred as indicated by a weak band at 1058.2 cm-1. The19F magic angle spinning NMR spectrum indicated the sample was 87% in the -SO2F form based on a chemical shift of -112 ppm for the CF2 group bonded to the -SO2F endgroup and a resonance at +44 ppm for the fluorine in the SO2F group. When subjected to repeat thermal history, melting and reforming the sample showed viscoelastic responses indicating extrusion processability.

[0189] Example 26. High conversion of chlorinated spray-dried 920EW PFSA to -SO2F form using KF in DMSO at 60°C.

[0190] A 7.60-g sample of chlorinated spray-dried 920EW PFSA powder from Example 23 was stirred with potassium fluoride (3.567 g, 61.39 mmoles) in dimethyl sulfoxide (112.673 g) at 60 °C for 2.5 hours. After cooling to room temperature, the product mixture was filtered and the product washed with water and acetone followed by vacuum drying. The ATR-IR spectrum had a strong band at 1466.3 cm-1indicating complete conversion of the -SO2CI endgroups to -SO2F endgroups; a small amount of hydrolysis had occurred as indicated by a weak band at 1057.3 cm-1.Conclusions.

[0191] It was discovered in the present disclosure that ionomers in a hydrolyzed form can be chlorinated to produce an at least partially chlorinated form with subsequent fluorination of the at least partially chlorinated form to produce an at least partially fluorinated form. The at least partially fluorinated form of the ionomer may be used as an ionomer precursor. The method of the present disclosure is therefore useful for recycling ionomers.

[0192] 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 andFP0022-W001 (45985-18) 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.

[0193] 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.

[0194] 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 a 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.

[0195] 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”.

[0196] 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.”

[0197] 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 oneFP0022-W001 (45985-18) 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).

[0198] 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.

[0199] As used herein, the term “about” means plus or minus 10% of the value.

[0200] As used herein, a “D50” particle size means that the portion of particles with diameters smaller than this value is 50%.

[0201] 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 -SOsM group, where M is as defined above.

[0202] 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, for example, hydrolysis. Ionomer precursors include polymers comprising at least one pendant -SO2F group.

[0203] As used herein, the term “at least partially chlorinated ionomer” means a polymer comprising pendant -SO2CI groups or a mixture of pendant -SO2CI groups with -SO2F groups and / or -SO3M groups, comprising at least one pendant -SO2CI group, where M is selected from H, alkali metals, alkaline earth metals, or a combination thereof. They represent an ionomer, where at least a portion of the - SO3M groups are converted to -SO2CI groups.

[0204] As used herein, the term “sulfonyl fluoride-containing polymer” means a polymer comprising pendant -SO2F groups or a mixture of pendant -SO2F groups with -SO3M groups and / or -SO2CI groups, comprising at least one pendant -SO2F group, where M is selected from H, alkali metals, alkaline earth metals, or a combination thereof. They represent an at least partially fluorinated ionomer, where at least a portion of the -SO2CI groups are converted to -SO2F groups.

Claims

FP0022-W001 (45985-18)WHAT IS CLAIMED IS:

1. A method comprising:I) forming a first mixture comprising: a) an ionomer comprising at least one pendant -SO3M group, wherein M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof; b) a chlorination reagent; and c) a chlorination solvent;II) reacting the first mixture to produce an at least partially chlorinated ionomer comprising at least one pendant -SO2CI group;III) forming a second mixture comprising: a) the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group; b) a fluorination reagent; and c) optionally a fluorination solvent; andIV) reacting the second mixture to produce a sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group.

2. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group is selected from perfluorosulfonic acid ionomers, at least partially fluorinated sulfonic acid ionomers, and combinations thereof.

3. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group is in a form selected from films, sheets, rolls, membranes, pellets, extrudates, particles, spray-dried particles, chips, flakes, powders, and combinations thereof.

4. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group is obtained from new ionomers, used ionomers, waste ionomers, recycled ionomers, and combinations thereof.

5. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm.FP0022-W001 (45985-18)6. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group has an equivalent weight in a range of from about 800 to about 1500.

7. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group has an ion exchange ratio in a range of from about 3.55 to about 13.2.

8. The method of claim 1 , wherein the chlorination reagent is selected from phosphorus(V) chlorination reagents; phosphorus(V) chlorination reagents generated in situ by reaction of chlorine and phosphorus(lll) precursor reagents RPCI2, wherein R is selected from Cl, alkyl, haloalkyl, aryl, and combinations thereof; phenyldichlorophosphine; and combinations thereof.

9. The method of claim 1 , wherein the chlorination solvent is inert to CI2 and strong Lewis acids, has a boiling point greater than about 80 °C, and is selected from halogenated arenes, trifluoromethyl-substituted arenes, trifluoromethylsubstituted halogenated arenes, and combinations thereof.

10. The method of claim 1 , wherein the chlorination solvent is selected from chlorobenzene, fluorobenzene, difluorobenzene, 1 ,2-dichlorobenzene, 1 ,2,4- trichlorobenzene, benzotrifluoride, hexafluoro-m-xylene, 4-chlorobenzotrifluoride, 2-chlorobenzotrifluoride, 2,4-dichlorobenzotrifluoride, 3,4- dichlorobenzotrifluoride, and combinations thereof.

11. The method of claim 1 , wherein reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 80 °C to about 150 °C.

12. The method of claim 1 , wherein reacting the first mixture comprises reacting the first mixture at a temperature in a range of from about 100 °C to about 135 °C.

13. The method of claim 1 , wherein reacting the first mixture comprises reacting the first mixture at atmospheric pressure.

14. The method of claim 1 , wherein reacting the first mixture comprises reacting the first mixture for a time in a range of from about 1 hour to about 24 hours.FP0022-W001 (45985-18)15. The method of claim 1 , further comprising processing the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof.

16. The method of claim 1 , further comprising recovering the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group after reacting the first mixture.

17. The method of claim 1 , wherein the fluorination reagent is selected from alkali metal fluorides.

18. The method of claim 1 , wherein the fluorination reagent is selected from lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, and combinations thereof.

19. The method of claim 1 , wherein the fluorination solvent is selected from anhydrous polar aprotic organic solvents.

20. The method of claim 1 , wherein the fluorination solvent is selected from nitriles, carboxylic amides, heterocyclic amides, sulfoxides and sulfones, and combinations thereof.

21. The method of claim 1 , wherein the fluorination solvent is selected from acetonitrile, butyronitrile, benzonitrile, N,N-dimethylformamide, dimethylacetamide, N-methyl formamide, formamide, 1 ,3-dimethyl-2- imidazolidinone, dimethyl sulfoxide, tetramethylene sulfone, and combinations thereof.

22. The method of claim 1 , wherein reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 25 °C to about 120 °C.

23. The method of claim 1 , wherein reacting the second mixture comprises reacting the second mixture at a temperature in a range of from about 40 °C to about 100 o / ^FP0022-W001 (45985-18)24. The method of claim 1 , wherein reacting the second mixture comprises reacting the second mixture for a time in a range of from about 1 hour to about 24 hours.

25. The method of claim 1 , further comprising processing the sulfonyl fluoride- containing polymer comprising at least one pendant -SO2F group after reacting the second mixture, wherein the processing comprises at least one technique selected from filtering, washing, removing volatiles, removing solvent, drying, and combinations thereof.

26. The method of claim 1 , further comprising recovering the sulfonyl fluoride- containing polymer comprising at least one pendant -SO2F group after reacting the second mixture.

27. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group comprises at least one -COOH group.

28. The method of claim 1 , wherein the first mixture further comprises a further component comprising at least one -COOH group.

29. The method of claim 1 , wherein the alkali metals are selected from Li, Na, K, Rb, Cs, and combinations thereof.

30. The method of claim 1 , wherein the alkaline-earth metals are selected from Mg, Ca, Sr, Ba, and combinations thereof.

31. A sulfonyl fluoride-containing polymer comprising at least one pendant -SO2F group produced according to the method of claim 1 .

32. The method of claim 1 , further comprising converting the sulfonyl fluoride- containing polymer comprising at least one pendant -SO2F group to a further ionomer comprising at least one -SO3M group, where M is selected from H, alkali metals, alkaline-earth metals, and combinations thereof.

33. An ionomer comprising at least one -SO3M group produced according to the method of claim 32.

34. A membrane comprising the ionomer comprising at least one -SO3M group of claim 33.FP0022-W001 (45985-18)35. A product comprising the ionomer comprising at least one -SO3M group of claim 33.

36. The product of claim 35, 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.

37. The method of claim 1 , further comprising the step of drying the ionomer comprising at least one pendant -SO3M group prior to forming the first mixture.

38. The method of claim 37, where the drying step is conducted at a temperature of about 40 °C to about 130 °C.

39. The method of claim 37, where the drying step is conducted at a temperature of about 40 °C to about 110 °C.

40. The method of claim 37, where the drying step is conducted at a reduced pressure of about 0.006 kPa to about 70.9 kPa.41 .The method of claim 37, where the drying step is conducted at a reduced pressure of about 10.1 kPa to about 70.7 kPa.

42. The method of claim 1 , where the ionomer comprising at least one pendant - SO3M group has a water content below about 6 weight percent, based on the total weight of the ionomer.

43. The method of claim 42, where the ionomer comprising at least one pendant - SO3M group has a water content below about 1 weight percent, based on the total weight of the ionomer.

44. The method of claim 1 , wherein the ionomer comprising at least one pendant - SO3M group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm.

45. The method of claim 1 , further comprising reducing the particle size of the ionomer comprising at least one pendant -SO3M group before step I.

46. The method of claim 1 , wherein the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 10 mm.FP0022-W001 (45985-18)47. The method of claim 1 , wherein the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group is in a form comprising particles having a particle size D50 in a range of from about 1 pm to about 100 pm.

48. The method of claim 1 , further comprising reducing the particle size of the at least partially chlorinated ionomer comprising at least one pendant -SO2CI group before step III.