Sulfonated polyarylene polymers and uses thereof

Abstract

The present invention relates to sulfonated polyarylene polymers and to their use for the manufacture of films, in particular suitable as ion exchange membranes for use in fuel cells, electrolyzers and redox flow batteries.

Description

SSPU 2024 / 034DescriptionSulfonated polyarylene polymers and uses thereofCross reference to related patent applications

[0001] The present invention claims priorities filed on 4 October 2024 in the USA with number 63 / 703595, and filed on 21 October 2024 in Europe, with number 24315488.7, the whole content of each of these patent applications being incorporated herein by reference for all purposes.Technical field

[0002] The present invention relates to sulfonated polyarylene polymers and to their use for the manufacture of films, in particular suitable as ion exchange membranes for use in electrochemical devices, including for example fuel cells, electrolyzers and redox flow batteries.Background

[0003] Fuel cells are devices that convert the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. They are highly efficient, environmentally friendly, and have been identified as a promising technology for clean energy conversion. A critical component of a fuel cell is the proton exchange membrane (PEM), which conducts protons from the anode to the cathode while blocking electrons to ensure the flow of electricity through an external circuit.

[0004] Polyarylene polymers have emerged as a promising class of materials due to their rigid backbone structure, which offers excellent thermal and chemical stability. However, the inherently hydrophobic nature of polyphenylenes limits their proton conductivity, a critical parameter for efficient fuel cell operation.

[0005] Several approaches have been attempted to enhance the proton conductivity of polyphenylene polymers. One such approach involves the sulfonation of the polyphenylene backbone, introducing sulfonic acid groups that can attract and hold water, thereby facilitating proton transport.SSPU 2024 / 034

[0006] The use of sulfonated polyarylene polymers has been disclosed in the art for the manufacture of ion-exchange membranes, which are non-porous films.

[0007] For example, US 5,403,675 (in the name of Maxdem, Inc.) discloses rigid-rod polyphenylene polymer, which has been sulfonated to contain from about 1% to about 30% by weight of sulfur. The backbone of such polymers is formed of phenylene units linked primarily at 1,4- positions. Preferably at least 80%, and more preferably at least 90% of the phenylene units have 1 ,4- linkages. Although in the description other linkages are disclosed as possible, no examples or characterization of such polymer was made in the text. Also, this patent discloses that a degree of sulfonation (expressed by the weight of sulfur deriving from -SO3H in the polymer divided by the total weight of the polymer) from about 1 wt.% to about 30 wt.% is desired. Indeed, the description mentions that it is not practical to provide a polymer where the percent by weight of sulfur is greater than about 30%.

[0008] More recently, US 7,868,124 (in the name of COMMISSARIAT A L'ENERGIE ATOMIQUE) discloses polymers comprising phenylene units, at least one of which bears a phenylene side group substituted with a perfluoro group or chain, which itself bears a -SO3H, -PO3H2 or -COOH group, and the use thereof to make fuel cell membranes.

[0009] LIM Y. et al. in “Studies of sulfonated polyphenylene membranes containing benzophenone moiety for PEMFC" (International Journal of Hydrogen Energy 39 (2014) 24595-21600) prepared sulfonated polyphenylenes containing benzophenone structure (sulfonated Parmax 1200, S-Parmax) with different degree of sulfonation and evaluated the ion exchange capacity (I EC) of membranes prepared with such polymers.

[0010] US 2014 / 0154610 (in the name of JSR Corporation) discloses an aromatic copolymer comprising: a hydrophilic segment (A) and a hydrophobic segment (B), where (A) comprises a structural unit having a proton conductive group and (B) comprising (*) a first divalent structural unit having an aromatic ring and no proton conductive groups and having two bonding sites at the para-position of one ring included in the aromatic ring and (*) a divalent structural unit having a benzene ring and being different from the first divalent structural unit. It is specified in the description that the polymer disclosed in this patent application is a block copolymer. In particular, segment (A) is formed by three, preferably five and more preferably ten or more structural units having a proton conductive group are continuous. Also,SSPU 2024 / 034 segment (B) is such that it is formed by five or more, preferably by ten or more continuous structural units. Also, Example 12 discloses a blocky sulfonated structure of formula:which is obtained by reacting a sulfonated monomer with the copolymerization product of 2,5-dichlorobenzophenone and m-dichlorobenzene. Based on the amounts of monomers used in the reaction, the ratio of recurring units containing the benzophenone group to all the recurring units is 39.5 mol% and the ratio of recurring units bonded in the meta position is 60.5 mol.%.Summary of the invention

[0011] The Applicant dedicated many efforts to develop new polymers characterized by high conductivity. Such polymers can advantageously be used for the manufacture of films, which can be used among other applications as membranes for the manufacture of fuel cells and electrolyzers.

[0012] Surprisingly, the Applicant prepared a new sulfonated polyphenylene polymer [polymer (sPP)] comprising phenylene repeating units linked in para and in meta position, wherein the repeating units in meta position are at least 25% by moles based on 100% moles of polymer (sPP).

[0013] Unexpectedly, the membranes prepared by said polymer (sPP) showed an increased conductivity when compared to membranes having a similar ion exchange capacity (I EC) but prepared from polymers having a lower number of units linked in meta position. For this reason, without being bound by any theory, the Applicant perceives that the position of the sulfonated groups in polymer (sPP), as achieved within the present invention, plays an important role in providing a membrane characterized by an increased conductivity.SSPU 2024 / 034

[0014] Advantageously, such polymer (sPP) can be used for the manufacture of films, and more in particular for the manufacture of membranes suitable for use in fuel cells and electrolyzers.Disclosure of the invention

[0015] As used in the present description and in the following claims:- the use of parentheses around symbols or numbers identifying the formulae, for example in expressions like “polymer (sPP)”, etc., has the mere purpose of better distinguishing the symbol or number from the rest of the text and, hence, said parenthesis can also be omitted;- the proportions of repeating units in a polymer are given relative to the total moles of repeating units in the polymer;- the concentration of repeating units in “percent by mol” or “mol%” or “% by mol” refers to the concentration of a given type of repeating unit relative to the total number of repeating units in the polymer, unless explicitly stated otherwise;- the expression “sulfonated polyphenylene polymer [polymer (sPP)]” is intended to indicate a polyphenylene polymer comprising repeating units (Rpm) and repeating units (Rpp) as represented hereinafter, wherein at least one a fraction of such repeating units (Rpm) and / or at least a fraction of such repeating units (Rpp) comprises at least one substituent -SO3H or the conjugated base thereof.

[0016] In the first aspect, the present invention relates to a sulfonated polyphenylene polymer [polymer (sPP)] comprising at least 25.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP), of repeating units (Rpm) complying with the following formula:wherein each of R1, R3, R4, is independently selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone, alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine, -SO3H or the conjugate baseSSPU 2024 / 034 thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof; andR2is selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone, alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine; and at least 10.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP), of repeating units (Rpp) complying with the following formula:wherein each of R5, R6, R7and R8is independently selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone, alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof; wherein, at least 10.0 mol.% or more of said repeating units (Rpm) based on 100 mol.% of repeating units (Rpm), comprise at least one of R1, R3and R4equal to -SO3H or the conjugated base thereof.

[0017] Advantageously, polymer (sPP) comprises repeating units (Rpm) in an amount higher than 30.0%, more preferably higher than 35.0% and even more preferably of at least 40.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP).

[0018] Preferably, polymer (sPP) comprises repeating units (Rpm) in an amount lower than 80.0%, more preferably lower than 75.0%, even more preferably lower than 70.0%, lower than 65.0% and still more preferably lower than 60.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP).

[0019] More preferably, polymer (sPP) comprises from more than 40.0% to 60.0% by moles and more preferably from 45.0% to 55.0% by moles of repeating units (Rpm), based on 100.0% by moles of repeating units in polymer (sPP).SSPU 2024 / 034

[0020] Preferably, each of R1, R3, and R4is independently selected from hydrogen atom, - SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and - COOH or the conjugated base thereof.

[0021] More preferably, one of R1, R3, and R4is selected from -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof, even more preferably -SO3H or the conjugated base thereof, and the other two substituents are each a hydrogen atom.

[0022] Preferably, R2is a hydrogen atom.

[0023] Accordingly, polymer (sPP) of the present invention comprises more than 10.0 mol.% and up to 100.0 mol.% of repeating unit (Rpm.s) based on 100 mol.% of repeating units (Rpm), said repeating units (Rpm-s) complying with the following formula:wherein one of R1, R3and R4is -SO3H or the conjugated base thereof, and each of the other substituents is a hydrogen atom.

[0024] Advantageously, polymer (sPP) comprises at least 15.0 mol.%, preferably at least 20.0 mol.%, more preferably at least 25.0 mol.%, even more preferably at least 30.0 mol.% and still more preferably at least 40.0 mol.% of repeating unit (Rpm-s) based on the total amount of repeating unit (Rpm).

[0025] Advantageously, polymer (sPP) comprises up to 100.0 mol.%, preferably up to 99.9 mol.%, more preferably up to 99.5 mol.%, even more preferably up to 99.0 mol.% of repeating units (Rpm-s) based on the total amount of repeating units (Rpm).

[0026] Preferably, polymer (sPP) comprises up to 97.0 mol.%, preferably up to 95.0 mol.%, more preferably up to 90.0 mol.% of repeating units (Rpm-s) based on the total amount of repeating units (Rpm).

[0027] The molar amount of repeating units (Rpm-s) can be calculated based on the ion exchange capacity measured for polymer (sPP).

[0028] It is particularly preferred that the polymer (sPP) of the present invention has an ion exchange capacity (IEC) of at least 1.85 meq / g. The ion exchange capacity (IEC) refers to the total number of active sites or functional groups in a polymer electrolyteSSPU 2024 / 034 membrane that are responsible for ion exchange. In the present description and in the following claims, the IEC is expressed as milli equivalents of -SO3H groups per gram of dry polymer.

[0029] Advantageously, the IEC of polymer (sPP) is at least 1.50 meq / g, preferably at least 1.75 meq / g and more preferably at least 1.80 meq / g as measured by titration.

[0030] Preferably, the IEC of polymer (sPP) is at most 4.50 meq / g, more preferably at most 4.00 meq / g and even more preferably at most 3.50 meq / g, as measured by titration.

[0031] Preferably, one or more of R5, R6, R7, and R8is independently represented by formula Ar-T-, wherein:Ar is represented by a formula selected from the following group of formulae:wherein each Rj, Rk and Ri is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine, quaternary ammonium, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof, j and I, equal or different from each other, being independently 0, 1 , 2, 3, 4, or 5 and, k, equal or different from j or I, being independently 0, 1 , 2, 3 or 4; andT is selected from the group consisting of -C(O)-; -CH2-; -O-; -SO2-; -S-; -C(CH3)2-;-C(CF3)2-; -C(=CCI2)-; -C(CH3)(CH2CH2COOH)-; -N=N-; -RaC=CRb-, wherein each Raand Rb, independently of one another, is hydrogen, C1-C12 alkyl, C1-C12 alkoxy, or Ce-Cis aryl group; -(CH2)n- and -(CF2)n- with n being an integer from 1 to 6; a linear or branched aliphatic divalent group having from 1 to 6 carbon atoms.SSPU 2024 / 034

[0032] More preferably, at least one of R5, R6, R7, and R8is represented by the following formula:wherein Rj- has the same meanings defined above for Rj.

[0033] Advantageously, polymer (sPP) comprises repeating units (Rpp) in an amount lower than 70.0%, more preferably lower than 65.0% and even more preferably of at most 60.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP).

[0034] Preferably, polymer (sPP) comprises repeating units (Rpp) in an amount higher than 20.0%, more preferably higher than 25.0%, even more preferably higher than 30.0%, higher than 35.0% and still more preferably higher than 40.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP).

[0035] More preferably, polymer (sPP) comprises more than 40.0% to at most 60.0% by moles and more preferably from 45.0% to 55.0% by moles of repeating units (Rpp), based on 100.0% by moles of repeating units in polymer (sPP).

[0036] According to an embodiment, the repeating unit (Rpp) is represented by the following formula:(RPP-I) wherein each of R5, R7and R8is independently selected from hydrogen atom, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof, andRj- is selected from a hydrogen atom, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof.

[0037] More preferably, each of R5, R7, R8and Rj- is a hydrogen atom.SSPU 2024 / 034

[0038] According to an embodiment, in a fraction of repeating units (RPP), one of R5, R7, R8and Rj” is -SO3H or the conjugated base thereof and the other substituents are each a hydrogen atom.

[0039] Without being bonded by any theory, the Applicant believes that polymer (sPP) prepared according to the method disclosed herein after does not comprise -SO3H groups as substituent of repeating unit (RPP). However, based on the reaction conditions selected in the method for the synthesis of polymer (sPP), it is not excluded that polymer (sPP) comprises repeating units of formula (Rpp-i) wherein at least one of Rj-, R5, R7and R8is -SO3H or the conjugated base thereof. Preferably, the amount of repeating units of formula (Rpp.i) comprising at least one of Rj-, R5, R7and R8= -SO3H or the conjugated base thereof, is lower than 10.0 mol% based on 100 mol% of polymer (sPP).

[0040] The method for the synthesis of polymer (sPP) is not limited.

[0041] Advantageously, polymer (sPP) can be prepared via a method comprising contacting a non-sulfonated polyphenylene polymer [polymer (PP)] with at least one sulfonating agent, thus obtaining polymer (sPP). Preferably, said sulfonating agent is selected from oleum, concentrated sulfuric acid, chlorosulfonic acid (CSA), SO3 adducts with another chemical reagent such as pyridine, acyl sulfate as described in WO 2020 / 009987 (in the name of Cytec Industries Inc.).

[0042] Such a method is preferably performed at a temperature from about 10 to about 70 °C, more preferably from 20 °C to about 65 °C.

[0043] Such a step of contacting said polymer (PP) with the sulfonating reactant is preferably performed for a time from about 30 minutes and up to about 15 hours.

[0044] The reaction conditions can be properly controlled to obtain a suitable ion exchange capacity, as described above.

[0045] After the completion of the polymerization reaction, polymer (sPP) can be isolated using known polymer isolation techniques.

[0046] Polymer (sPP) may be precipitated by mixing a solvent in which polymer (sPP) is poorly soluble with the reaction mixture, to precipitate the polyarylene polymer and separating the polyarylene polymer precipitated from the reaction mixture by filtration.

[0047] Alternatively, after post functionalization, i.e. sulfonation of the polymer, droplets of the reaction mixture are dropped, for instance by means of a nozzle, in a precipitation bath containing a solvent in which polymer (sPP) is poorly soluble.SSPU 2024 / 034

[0048] Examples of the solvent in which polymer (sPP) is insoluble or poorly soluble include water, glacial acetic acid, methanol, ethanol, acetonitrile, diluted sulfuric acid. Water, glacial acetic acid are preferable.

[0049] The precipitated polymer (sPP) may then be washed to remove any traces of the residual acids, and then dried.

[0050] Polymer (sPP) may then be ground or sieved to obtain a powder comprising particles of the desired particle size as known to the person skilled in the art.

[0051] Polymer (sPP) may be in the form of a powder. The solid particles of polymer (sPP) may have an average size of nanometers to millimeters, preferably from microns to millimeters. The average particle size can be in the range of 50 microns to 20 mm, from 100 microns to 10 mm or even from 200 microns to 5 mm.

[0052] The powder of polymer (sPP) is typically free flowing.

[0053] For the preparation of the membranes according to the present invention, preferably polymer (sPP) is provided in the form of a liquid composition.

[0054] Advantageously, said liquid composition is in the form of a solution, or alternatively of a dispersion, in a suitable solvent, in particular an organic solvent.

[0055] Examples of suitable solvents, are for instance selected from the group consisting of tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N,N-dimethylformamide, N,N- dimethylacetamide, N,N-dimethyl lactamide, N-methyl-2-pyrrolidone, N-butyl-2- pyrrolidone, y-butyrolactone and y-butyrolactam. More preferred are dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-butyl-2-pyrrolidone, and mixtures thereof.

[0056] Polymer (sPP) is advantageously used to manufacture a film, such as a dense film or dense membrane, including proton conductive membranes for electrolysers, redox flow batteries and fuel cells, as well as solid electrolytes for display elements, sensors, signal transmission media, solid capacitors and the like.

[0057] Thus, in another aspect, the present invention relates to an article comprising polymer (sPP).

[0058] Preferably, said article in the form of a film.

[0059] More preferably, such film has a thickness from 5 to 300 micrometers, preferably from 10 to 150 micrometers and more preferably from 15 to 100 micrometers.

[0060] According to a preferred aspect, the film of the present invention is a polymer electrolyte membrane.SSPU 2024 / 034

[0061] The expression “polymer electrolyte membrane” is intended to indicate a film of polymeric material characterized by ion exchange properties due to the presence of ion exchange functional groups.

[0062] The method for manufacturing the membrane of the present invention is not limited.

[0063] Preferably, a method for manufacturing the membrane as defined above comprises the following steps: i) providing a liquid composition [composition (CL)] comprising at least polymer (sPP) as defined above and a liquid medium [medium (L)] ; ii) processing said composition (CL) provided in step (i) to provide a film; and iii) separating said at least one solvent from the film provided in step (ii); thus obtaining the membrane as defined above.

[0064] Preferably, said medium (L) is a solvent selected in the group comprising polar aprotic solvent. More preferably, said at least one polar aprotic solvent is selected in the group comprising, preferably consisting of: N-butyl-2-pyrrolidone, N-methyl- pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), tetrahydrofuran (THF), methyl-5-dimethylamino-2-methyl- 5- oxopentanoate (commercially available under the trade name Rhodiasolv Polarclean®), triethylphosphate (TEP) and mixtures thereof.

[0065] Preferably, composition (CL) is manufactured by any conventional techniques. For instance, the medium (L) may be added to polymer (sPP), or, preferably, polymer (sPP) may be added to the medium (L), or even polymer (sPP) and the medium (L) may be simultaneously mixed.

[0066] Any suitable mixing equipment may be used. Preferably, the mixing equipment is selected to reduce the amount of air entrapped in composition (CL) which may cause defects in the final membrane. The mixing of polymer (sPP) and the medium (L) may be conveniently carried out in a sealed container, optionally held under an inert atmosphere. Inert atmosphere, and more precisely nitrogen atmosphere has been found particularly advantageous for the manufacture of composition (CL).

[0067] Under step (ii), composition (CL) is typically processed in liquid phase, preferably in the form of a solution or of a dispersion. Under step (ii), composition (CL) is typically processed by casting thereby providing a film.

[0068] Casting generally involves a casting blade, a draw-down bar or a slot die is used to spread an even film of a liquid composition comprising a suitable medium (L) across a suitable support.SSPU 2024 / 034

[0069] Under step (ii), the temperature at which composition (CL) is processed by casting may be or may be not the same as the temperature at which composition (CL) is mixed under stirring.

[0070] Composition (CL) is preferably cast as a film over a flat supporting substrate, typically a plate, a belt or a fabric, or another microporous supporting membrane, typically by means of a casting knife, a draw-down bar or a slot die.

[0071] According to an embodiment of step (ii), composition (CL) is processed by casting onto a flat supporting substrate to provide a flat film.

[0072] Preferably, step (iii) is performed by evaporating said at least one solvent from the film of step (ii).

[0073] Alternatively, said step (iii) is performed by precipitating the film provided in step (ii).

[0074] Optionally, step (iii) is followed by a step of washing, for example with water or acidic to remove residual solvent(s).

[0075] According to another embodiment, the membrane according to the present invention can be manufactured by processing a polyphenylene polymer, which is a polymer without any group -SO3H or the conjugated base thereof, into a membrane as disclosed above, and sulfonating said membrane, for example by contacting it with oleum, concentrated sulfuric acid or chlorosulfonic acid. Such sulfonation step can be performed in the presence or in the absence of a solvent.

[0076] Advantageously, the membrane according to the present invention has a conductivity of at least 200 mS / cm as measured in water at 80 °C, as disclosed in more detail in the examples.

[0077] In still another aspect, the present invention relates to the use of a membrane as defined above in fuel cell(s), water electrolyzer(s) and redox flow battery(ies).

[0078] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0079] The present invention will be now described in more detail with reference to the following examples, whose purpose is merely illustrative and not intended to limit the scope of the disclosure.SSPU 2024 / 034

[0080] EXAMPLES

[0081] Materials

[0082] Polymer (A1) = p-phenylene substituted by a phenylketone group I m-phenylene in a mole ratio 50 / 50, having weight average molecular weight = 100000 g / mol as determined by GPC analysis Polymer (A2) = p-phenylene substituted by a phenylketone group I m-phenylene in a mole ratio 50 / 50, having weight average molecular weight = 71000 g / mol as determined by GPC analysis Polymer (B) = p-phenylene substituted by a phenylketone group I m-phenylene in a mole ratio 85 / 15, having weight average molecular weight = 149000 g / mol as determined by GPC analysis all available from Solvay Specialty Polymers USA, LLC.

[0083] Molecular weight determination Method - GPC

[0084] Gel permeation chromatography (GPC) analyses were carried out using a Waters 2695 Separations Module and a Waters 2487 Dual Wavelength Absorbance detector with dimethylacetamide (0.1 M LiBr) as an eluent on two PLgel 5 urn minimixed - D columns (250 x 4.6 mm) and a PLgel 5um MiniMIX-D Guard (50 x 4.6 mm). An ultraviolet detector monitoring 270 nm was used to obtain the chromatogram. A flow rate of 0.3 ml I min and injection volume of 5 uL of a 0.2 w / v % solution in mobile phase was selected. Calibration was performed with 10 narrow molecular weight polystyrene standards (Peak molecular weight range: 371 ,000 to 580 g I mol). The weight average molecular weight Mw was reported.

[0085] Synthesis of sulfonated polymers (sPP)

[0086] The reactions were performed in a double-shell glass reactor (250 mL) with an air condenser and a thermostatically controlled bath. The agitation was performed with a glass stirrer (A320) connected to an I KA stirring motor equipped with a temperature probe. The temperature and agitation speed were monitored and recorded.

[0087] Polymer (sPP-1)

[0088] Oleum 20-30% (commercially available, titrated 25 wt.%; 192 g, 100 mL) was introduced into the reactor under argon flush. 10 g of polymer (A1) were added at one-time at 25 °C and under stirring speed at 600 rpm, followed by a second portionSSPU 2024 / 034 of oleum 20-30% (titrated 25%; 192 g, 100 mL). The reaction mixture was heated up to 40 °C. After 5 hours at 40 °C, the medium was cooled down to 15 °C and poured in a stirred erlenmeyer containing a 1 / 1 mixture of water and ice (1250 g / 1250 g).

[0089] The mixture was then filtered on disposable Nalgene® bottle-top sterile filter units PES, pore size 0.2 pm. The cake was then washed with deionized water until pH around 6 and finally dried in a ventilated oven at 50 °C overnight to provide mass of 6.0 g.

[0090] Polymer (sPP-2)

[0091] The polymer was prepared following the procedure disclosed above for polymer (sPP-1) starting from polymer (A1) but the reaction with oleum was performed for 3 hours.The obtained mass was 5.0 g.

[0092] Polymer (sPP-3)

[0093] The polymer was prepared following the same procedure disclosed above for polymer (sPP-1), but starting from polymer (A2) and the reaction with oleum was performed for 3 hours. Mass = 12.2 g

[0094] Polymer (sPP-4)

[0095] The polymer was prepared following the same procedure disclosed above for polymer (sPP-1), but starting from polymer (A2). Mass = 12.7 g

[0096] Polymer (sPP-5)

[0097] The polymer was prepared following the same procedure disclosed above for polymer (sPP-1), but starting from polymer (A2) and the reaction with oleum was performed for 2.5 hours.Mass = 12.3 gSSPU 2024 / 034

[0098] Polymer (sPP-1C) of comparison

[0099] The polymer was prepared following the same procedure disclosed above for polymer (sPP-1), using polymer (B) as starting material.

[0100] Preparation of the membranes

[0101] The polymer (1.51 g) was dissolved in 9.13 g of NMP at 80 °C under nitrogen. The solution was filtered at 80 °C with a 5 micron syringe filter. After filtration, the solution was allowed to rest at room temperature to remove bubbles in the solution. A portion of the prepared solution was heated again to 80 °C and cast on a glass plate substrate at 80 °C using a doctor blade. It was transferred on the glass substrate in a N2 flowing oven preheated at 80 °C. After 20 minutes, the temperature was set at 150 °C and the membrane was dried in the oven at 150 °C for 18 hours. Each membrane was soaked in deionized water for 1 hour then in four other deionized water baths for 5 or 30 minutes. It was then allowed to dry at room temperature before measuring cationic conductivity.

[0102] Titration method

[0103] The ion exchange capacity (I EC) was determined using the acid-base titration method. The samples were soaked for one or two nights in 10 ml or 5 ml of 0.1 M NaOH + 5 ml of water to exchange sodium ions for protons. The excess NaOH remaining in the solution after ionic exchange was titrated with 0.1M HCI using the pH-metry method taking into account the carbonation of NaOH. For each sample, at least two repetitions were performed (if enough sample was available to do so). 2 blanks were performed under the same conditions.

[0104] Conductivity of the membranes was measured using the following method. A BekkTech conductivity cell was used, with a four-electrode system that provides the ability to separate the voltage drop due to ion creation, from the voltage drop due to ion flow.To measure proton conductivity, the membrane was cut in appropriate shape, put in the Bekktech cell, and then the cell was immersed into a Milli-Q water bath previously set at 80 °C. Electrochemical measures of conductivity / resistivity were performed though linear voltage sweep.SSPU 2024 / 034The results are summarized in the following Table 1.Table 1(*) comparison

Claims

SSPU 2024 / 034Claims1. A sulfonated polyphenylene polymer [polymer (sPP)] comprising at least 25.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP), of repeating units (Rpm) complying with the following formula:wherein each of R1, R3, R4, is independently selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone, alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof; andR2is selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone, alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine; and at least 10.0% by moles, based on 100.0% by moles of repeating units in polymer (sPP), of repeating units (Rpp) complying with the following formula:wherein each of R1, R2, R3, R4, R5, R6, R7and R8is independently selected from the group consisting of: hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylketone, arylketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkylsulfone, arylsulfone,SSPU 2024 / 034 alkylamide, arylamide, alkylester, arylester, fluorine, chlorine, bromine, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof; wherein, at least 10.0 mol.% of said repeating units (Rpm) based on 100 mol.% of repeating units (Rpm), comprise at least one of R1, R3and R4equal to -SO3H or the conjugated base thereof.

2. The polymer (sPP) according to Claim 1 , said polymer (sPP) comprising:- at least 40.0% by moles of repeating units (Rpm), based on 100.0% by moles of repeating units in polymer (sPP); and / or- less than 60.0% by moles of repeating units (Rpm), based on 100.0% by moles of repeating units in polymer (sPP).

3. The polymer (sPP) according to Claim 1 or 2, said polymer (sPP) comprising more than 10.0 mol.% and up to 100.0 mol.% of repeating unit (Rpm-s) based on 100 mol.% of repeating units (Rpm), said repeating unit (Rpm-s) complying with the following formula:wherein one of R1, R3and R4is -SO3H or the conjugated base thereof, and each of the other substituents is hydrogen atom.

4. The polymer (sPP) according to any one of the preceding Claims, wherein said polymer (sPP) comprises:- at least 15.0 mol.%, preferably at least 20.0 mol.%, more preferably at least 25.0 mol.% and even more preferably at least 30.0 mol.% of repeating units (Rpm-s) based on the total amount of repeating units (Rpm); and / or- up to 100.0 mol.%, preferably up to 99.9 mol.%, more preferably less than 99.5 mol.% and even more preferably up to 99.0 mol.% of repeating units (Rpm-s) based onSSPU 2024 / 034 the total amount of repeating units (Rpm).

5. The polymer (sPP) according to any one of the preceding Claims, wherein said polymer (sPP) has an ion exchange capacity (I EC) of at least 1.50 meq / g, the I EC being expressed as milliequivalents of -SO3H groups per gram of dry polymer as measured via titration.

6. The polymer (sPP) according to any one of the preceding Claims, wherein one or more of R5, R6, R7, and R8is independently represented by formula Ar-T-, wherein: Ar is represented by a formula selected from the following group of formulae:wherein each Rj, Rkand Ri is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine, quaternary ammonium, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof, j and I, equal or different from each other, being independently 0, 1 , 2, 3, 4, or 5 and, k, equal or different from j or I, being independently 0, 1 , 2, 3 or 4; andT is selected from the group consisting of -C(O)-; -CH2-; -O-; -SO2-; -S-; -C(CH3)2-; - C(CF3)2-; -C(=CCI2)-; -C(CH3)(CH2CH2COOH)-; -N=N-; -RaC=CRb-, wherein each Raand Rb, independently of one another, is hydrogen, C1-C12 alkyl, C1- C12 alkoxy, or Ce-Cis aryl group; -(CH2)n- and -(CF2)n- with n being an integer from 1 to 6; a linear or branched aliphatic divalent group having from 1 to 6 carbon atoms.

7. The polymer (sPP) according to Claim 6, wherein at least one of R5, R6, R7, and R8isS SPU 2024 / 034 represented by the following formula:wherein Rj- selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine, quaternary ammonium, -SO3H or the conjugate base thereof, - PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof.

8. The polymer (sPP) according to any one of the preceding Claims, wherein said polymer (sPP) comprises:- at most 60.0% by moles of repeating units (Rpp), based on 100.0% by moles of repeating units in polymer (sPP); and / or- more than 40.0% by moles of repeating units (Rpp), based on 100.0% by moles of repeating units in polymer (sPP).

9. The polymer (sPP) according to any one of the preceding Claims, wherein said repeating unit (Rpp) is represented by the following formula:(RPP-I) wherein each of R5, R7and R8is independently selected from hydrogen atom, -SO3H or the conjugate base thereof, -PO3H2 or the conjugated bases thereof, and -COOH or the conjugated base thereof, andRj- is selected from a hydrogen atom, -SO3H or the conjugate base thereof, -PO3H2SSPU 2024 / 034 or the conjugated bases thereof, and -COOH or the conjugated base thereof.

10. The polymer (sPP) according to Claim 9, wherein said polymer (sPP) comprises:- less than 10.0 mol.% based on 100 mol.% of polymer (sPP) of repeating units of formula (RPP.|):(RPP-I) wherein at least one of Rj-, R5, R7and R8is -SO3H or the conjugated base thereof and the others are hydrogen atoms.

11. A method for the manufacture of polymer (sPP) according to any one of Claims 1 to 10, said method comprising:- providing a non-sulfonated polyphenylene polymer [polymer (PP)],- contacting said polymer (PP) and at least one sulfonating agent selected from oleum, concentrated sulfuric acid, chlorosulfonic acid (CSA), SO3 adducts and acyl sulfate, thus obtaining polymer (sPP).

12. The method according to Claim 11 , wherein said method is performed at a temperature from about 10 to about 70 °C and / or for a time from about 30 minutes to 15 hours.

13. An article comprising polymer (sPP) according to any one of Claims 1 to 10.

14. The article according to Claim 14, said article being selected from dense film or dense membrane, including proton conductive membranes for electrolysers, redox flow batteries and fuel cells, as well as solid electrolytes for display elements, sensors, signal transmission media, solid capacitors and the like.S SPU 2024 / 03415. A method for manufacturing a membrane, said method comprising the steps of: i) providing a liquid composition [composition (CL)] comprising at least polymer (sPP) according to any one of Claims 1 to 10 and a liquid medium [medium (L)] ; ii) processing said composition (CL) provided in step (i) to provide a film; and iii) separating said at least one solvent from the film provided in step (ii); thus obtaining a membrane.

16. Use of a dense film or a dense membrane according to Claim 14 in fuel cell(s), water electrolyzer(s) and redox flow battery(ies).

Images