High performance hybrid fluoropolymer composite membranes

Abstract

The present invention relates to a method for the preparation of fluoropolymer hybrid organic / inorganic composite materials, to polymer electrolyte membranes based on said fluoropolymers, and to the use of said electrolyte membranes in various applications, in particular electrochemical applications.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application No. 21213289.8, filed December 9, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to a method for the preparation of fluoropolymer hybrid organic / inorganic composite materials, to polymer electrolyte membranes based on said fluoropolymers, and to the use of said electrolyte membranes in various applications, in particular electrochemical applications. [Background technology]

[0003] Organic-inorganic polymer hybrids, in which inorganic solids are dispersed in organic polymers at the nano- or molecular level, have attracted considerable scientific, technological and industrial interest due to their unique properties.

[0004] To fabricate organic-inorganic polymer hybrid composites, the sol-gel method using metal alkoxides is the most useful and important technique.

[0005] By appropriately controlling the reaction conditions for the hydrolysis and polycondensation of metal alkoxides, especially alkoxysilanes (e.g., tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS)), in the presence of preformed organic polymers, it is possible to obtain hybrids with improved properties compared to the parent compounds. The polymers can improve the toughness and processability of otherwise brittle inorganic materials, where the inorganic network can improve the scratch resistance, mechanical properties and surface properties of the hybrids.

[0006] Hybrids made by the sol-gel technique starting from fluoropolymers, particularly vinylidene fluoride polymers, are known in the art.

[0007] For example, WO 2013 / 160240 discloses the preparation of a fluoropolymer hybrid organic / inorganic composite in the presence of a liquid medium to provide a free-standing fluoropolymer membrane that stably contains and retains the liquid medium and has outstanding ionic conductivity. The hybrid organic / inorganic composite can be obtained by a method that includes reacting the -OH functional groups of a specific functionalized fluoropolymer with a silyl isocyanate and an alkoxysilane in the presence of a liquid medium and one electrolytic salt, and then hydrolyzing and / or polycondensing the mixture. The resulting liquid mixture is then processed into a membrane by a solvent casting procedure and dried to obtain the membrane. The membrane can be used as a polymer membrane suitable for use in electrochemical devices such as secondary batteries. The use of silyl isocyanate is said to be essential in the method using an organic carbonate as the liquid medium.

[0008] Unfortunately, due to specific reactivity and reaction conditions, isocyanate-based processes limit the fluoropolymer choices to those that contain repeat units derived from monomers with hydroxyl functionality.

[0009] Therefore, there is a need in the art for a method of making fluoropolymer hybrid organic / inorganic composites that are suitable for preparing composites containing different grades of fluoropolymers.

[0010] The inventors have unexpectedly demonstrated that the method of the present invention, utilizing certain universal metal compounds as grafting agents, allows for the successful preparation of a variety of fluoropolymer hybrid organic / inorganic composites, with the added benefit of providing composites with improved mechanical properties and flexibility. Summary of the Invention

[0011] The object of the present invention is therefore a method for the preparation of a fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)], said method comprising the steps of: (i) preparing a composition [composition (C1)] comprising a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], said polymer (F) being - repeat units derived from at least one fluorinated monomer [monomer (FM)]; - repeat units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl, amine, carboxyl, thiol and anhydride; (ii) mixing composition (C1) with at least a first metal compound of formula (I) [Compound (M1)]: X 4-m AY m (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. to react at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY m obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (Fj)] having pendant groups; (iii) reacting composition (C2) with at least one second metal compound of formula (II) different from compound (M1) [compound (M2)]: X' 4-m’ A'Y' m’ (II) wherein m' is an integer from 1 to 4, A' is a metal selected from the group consisting of Si, Ti, and Zr, each occurrence of Y' is a hydrolyzable group, and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX'). to contact at least a portion of the compound (M2) with -AY of the polymer (Fj). mWith at least a portion of the pendant groups, thereby forming -A'Y' m obtaining a composition [composition (C3)] comprising at least one grafted fluoropolymer [polymer (Fg)] having pendant groups; and (iv) -A'Y' of polymer (Fg) m hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4)] comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)]; Includes.

[0012] A second object of the present invention relates to the fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] obtainable by the process of the present invention.

[0013] The polymer (Fj) formed in step (ii) of the process of the invention is novel and represents a further aspect of the invention.

[0014] In another object, the present invention provides a fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] according to the present invention.

[0015] The present invention therefore further relates to a method for producing a fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)]. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The polymer (F) is typically obtained by polymerization of at least one monomer (FM) and at least one monomer (FPM).

[0017] The monomers (FPM) may be chosen from (per)fluorinated and hydrogenated monomers comprising at least one functional group [group (FX)].

[0018] Suitable hydrogenated monomers (FPM) are monomers of formula (III): [ka] (In the formula, R1, R2 and R3 are equal to or different from each other and are independently selected from a hydrogen atom and a C1-C3 hydrocarbon group; R X is a C1-C 1 -C 2 -C 3 -C 4 -C 5 -C 6 -C 7 -C 8 -C 9 -C 10 -C 11 -C 12 -C 13 -C 14 -C 15 -C 16 -C 17 -C 18 -C 19 -C 20 -C 21 -C 22 -C 23 -C 24 -C 20 (the hydrocarbon moiety).

[0019] Rx may contain a functional group different from the group (FX) and may also contain a heteroatom.

[0020] The term "fluorinated monomer (FM)" is intended herein to mean an ethylenically unsaturated monomer that contains at least one fluorine atom.

[0021] The term "at least one fluorinated monomer" is understood to mean that the polymer (F) may contain repeat units derived from one or more fluorinated monomers. In the remainder of the text, the expressions "fluorinated monomers" are understood for the purposes of the present invention both in the plural and in the singular, i.e. they mean both one or more fluorinated monomers as defined above.

[0022] Non-limiting examples of suitable monomers (FM) include, inter alia: - C2-C8 perfluoroolefins, such as tetrafluoroethylene and hexafluoropropylene; - C2-C8 hydrogenated fluoroolefins, such as vinylidene fluoride, vinyl fluoride, 1,2-difluoroethylene and trifluoroethylene; - Formula CH2=CH-R f0 (In the formula, R f0 is a C1-C6 perfluoroalkyl) perfluoroalkylethylene; - chloro- and / or bromo- and / or iodo-C2-C6 fluoroolefins, for example chlorotrifluoroethylene; - Formula CF2=CFOR f1 (In the formula, R f1 is C1-C6 fluoro- or perfluoroalkyl, for example CF3, C2F5, C3F7), (per)fluoroalkyl vinyl ethers; - CF2 = CFOX0 (per)fluoro-oxyalkyl vinyl ether (wherein X0 is C1-C 12 Alkyl groups, C1-C 12 C1-C having one or more ether groups such as oxyalkyl groups or perfluoro-2-propoxy-propyl groups 12 (per)fluorooxyalkyl group; - Formula CF2=CFOCF2OR f2 (In the formula, R f2 is a C1-C6 fluoro- or perfluoroalkyl group, for example, a C1-C6 (per)fluorooxyalkyl group having one or more ether groups, such as CF3, C2F5, C3F7, or -C2F5-O-CF3; (per)fluoroalkyl vinyl ethers of - Formula CF2 = CFOY0 (wherein Y0 is C1 to C 12 Alkyl group or (per)fluoroalkyl group, C1-C 12 C1-C having an oxyalkyl group or one or more ether groups 12 (per)fluorooxyalkyl groups, Y0 containing a carboxylic or sulfonic acid group in the form of its acid, acid halide or salt); Mention may be made of fluorodioxoles, preferably perfluorodioxoles.

[0023] A preferred polymer (F) is one containing repeating units derived from at least one monomer (FM) selected from the group consisting of vinylidene fluoride (VDF), tetrafluoroethylene (TFE), and chlorotrifluoroethylene (CTFE).

[0024] The polymer (F) typically comprises at least one monomer of formula (III) [monomer (FPM)]: [ka] (In the formula, R1, R2 and R3 are equal to or different from each other and are independently selected from a hydrogen atom and a C1-C3 hydrocarbon group; R X is a C1-C 1 -C 2 -C 3 -C 4 -C 5 -C 6 -C 7 -C 8 -C 9 -C 10 -C 11 -C 12 -C 13 -C 14 -C 15 -C 16 -C 17 -C 18 -C 19 -C 20 -C 21 -C 22 -C 23 -C 24 -C 20 The repeating unit derived from the hydrocarbon moiety is 0.02 mol % to 5.0 mol %; The said mole percentages relate to the total number of moles of repeating units of polymer (F). Rx may contain a functional group different from the group (FX) and may also contain a heteroatom.

[0025] The monomers (FPM) are in particular selected from the group consisting of (meth)acrylic monomers of formula (IV): [ka] (wherein R1, R2, and R3 are as defined above, and RH is a hydrogen atom or at least one functional group [group (FX H )] C1 to C 20 More preferably, the functional group (FX H ) is selected from the group consisting of a hydroxyl group and a carboxyl group.

[0026] Non-limiting examples of monomers (FPM) include, among others, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, acrylic acid (AA), and succinic acid 1-[2-(acryloyloxy)propyl] ester.

[0027] When the functional group (FX) in the monomer (FPM) is an amine, it may be suitably selected from primary and secondary amines, said amines may be both aliphatic and aromatic amines.

[0028] The determination of the average molar percentage of the repeating monomer (FRM) units in the polymer (F) can be carried out by any suitable method, in particular by acid-base titration (suitable for determining, for example, the carboxylic acid content), by NMR methods (suitable for quantifying the monomers (FPM) containing aliphatic hydrogen atoms in their side chains), by weight balance based on the total fed monomers (FPM) and unreacted residual monomers (FPM) during the preparation of the polymer (F).

[0029] In a particularly preferred embodiment, the monomers (FPM) are randomly distributed in the polymer (F). In said embodiment, a proportion of the monomers (FPM) of at least 40% is randomly distributed in said polymer (F).

[0030] The expression "randomly distributed in the polymer (F)" is intended to express the percentage ratio between the average number (%) of monomer (FPM) sequences between two repeat units derived from a monomer (FM) and the average total number (%) of monomer (FPM) repeat units according to the following formula:

number

[0031] If each of the (FPM) repeat units is isolated, i.e. contained between two repeat units of a monomer (FM), then the average number of (FPM) sequences is equal to the average total number of (FPM) repeat units and therefore the percentage of randomly distributed units (FPM) is 100%: this value corresponds to a completely random distribution of the (FPM) repeat units.

[0032] Thus, as stated above, the greater the number of isolated (FPM) units relative to the total number of (FPM) units, the higher the percentage value of the portion of randomly distributed units (FPM) will be.

[0033] The polymer (F) can be amorphous or semi-crystalline.

[0034] The term "amorphous" is intended herein to mean a polymer (F) having a heat of fusion, measured according to ASTM D-3418-08, of less than 5 J / g, preferably less than 3 J / g, more preferably less than 2 J / g.

[0035] The term "semi-crystalline" is intended herein to mean a polymer (F) having a heat of fusion, measured according to ASTM D3418-08, of between 10 and 90 J / g, preferably between 30 and 60 J / g, more preferably between 35 and 55 J / g.

[0036] The polymer (F) is preferably semi-crystalline.

[0037] Preferably, the intrinsic viscosity of the polymer (F), measured in dimethylformamide at 25° C., is comprised between 0.05 l / g and 0.80 l / g, more preferably between 0.10 l / g and 0.50 l / g, even more preferably between 0.2 l / g and 0.4 l / g.

[0038] Preferred polymers (F) are those that comprise one or more backbones, said backbones comprising repeating units derived from at least one monomer (FM) selected from the group consisting of vinylidene fluoride (VDF), tetrafluoroethylene (TFE), and chlorotrifluoroethylene (CTFE).

[0039] The polymer (F) preferably comprises units derived from vinylidene fluoride (FPM) and from at least one monomer (MA) as defined above, and optionally also comprises repeat units derived from at least one additional monomer (FM) different from VDF. The additional monomer (FM) in the polymer (F) is preferably HFP.

[0040] The polymer (F) is preferably: (a) at least 60 mol %, preferably at least 75 mol %, more preferably at least 85 mol % vinylidene fluoride (VDF); (b) optionally, 0.1 mol % to 15 mol %, preferably 0.5 mol % to 10 mol %, more preferably 1 mol % to 5 mol % of at least one monomer (FM) selected from vinyl fluoride (VF1), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), and perfluoromethyl vinyl ether (PMVE); (c) 0.01 mol % to 10 mol %, preferably 0.05 mol % to 5 mol %, more preferably 0.1 mol % to 2 mol % of at least one monomer of formula (III) (FPM) as defined above; Includes.

[0041] The polymer (F) is typically obtained by emulsion or suspension polymerization.

[0042] In a particularly preferred embodiment, the polymer (F) used in the process of the invention is (a) at least 60 mol %, preferably at least 75 mol %, more preferably at least 85 mol % vinylidene fluoride (VDF); (b) optionally, 0.1 mol % to 15 mol %, preferably 0.5 mol % to 10 mol %, more preferably 1 mol % to 5 mol % of at least one monomer (FM) selected from vinyl fluoride (VF1), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), and perfluoromethyl vinyl ether (PMVE); (c) 0.01 mol % to 10 mol %, preferably 0.05 mol % to 5 mol %, more preferably 0.1 mol % to 2 mol % of acrylic acid (AA); Including, Said polymer (F) has an intrinsic viscosity, measured in dimethylformamide at 25° C., comprised between 0.2 l / g and 0.4 l / g.

[0043] For the purposes of the present invention, the term "liquid medium [medium (L)]" is intended herein to refer to a composition comprising one or more substances that are in a liquid state at 20° C. under atmospheric pressure.

[0044] According to some embodiments of the present invention, the medium (L) is preferably selected from an organic carbonate, an ionic liquid (IL), a solvent (S), or a mixture thereof.

[0045] Within the present invention, solvent (S) is intended to denote a solvent suitable for dissolving the polymer (F) defined above. For this purpose, the solvent (S) is typically selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphamide, dioxane, tetrahydrofuran, tetramethylurea, triethylphosphate, trimethylphosphate, aliphatic ketones, cycloaliphatic ketones, and cycloaliphatic esters. These solvents can be used alone or in a mixture of two or more species.

[0046] According to a first embodiment of the invention, said medium (L) comprises at least one organic carbonate as the only medium (L).

[0047] Non-limiting examples of suitable organic carbonates include, among others, ethylene carbonate, propylene carbonate, mixtures of ethylene carbonate and propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl-methyl carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate, and mixtures thereof.

[0048] According to a second embodiment of the invention, said medium (L) comprises at least one ionic liquid (IL) as the only medium (L).

[0049] The term "ionic liquid (IL)" is intended herein to denote compounds formed by the combination of positively charged cations and negatively charged anions that exist in the liquid state at temperatures below 100° C. under atmospheric pressure.

[0050] Ionic liquids (ILs) are protic ionic liquids (ILs p ), aprotic ionic liquids (IL a ), and mixtures thereof.

[0051] "Protic Ionic Liquids (ILs) p The term "cation" as used herein means a cation having one or more H + It is intended to denote ionic liquids that contain hydrogen ions.

[0052] One or more H + Non-limiting examples of cations containing hydrogen ions include imidazolium, pyridinium, pyrrolidinium, or piperidinium rings, among others, where the positively charged nitrogen atom is H + is bonded to a hydrogen ion.

[0053] Aprotic ionic liquids (ILs) a )" is used herein to refer to a compound in which the cation is H + It is intended to denote ionic liquids that do not contain hydrogen ions.

[0054] The ionic liquids (IL) are typically chosen from those containing as cations a sulfonium ion or an imidazolium, pyridinium, pyrrolidium or piperidium ring, which may optionally be substituted at the nitrogen atom, in particular by one or more alkyl groups having 1 to 8 carbon atoms, and also at the carbon atoms, in particular by one or more alkyl groups having 1 to 30 carbon atoms.

[0055] According to another embodiment of the invention, said medium (L) comprises a mixture of at least one organic carbonate as defined above and at least one ionic liquid (IL) as defined above.

[0056] According to a further embodiment of the invention, said medium (L) comprises a mixture of at least one organic solvent as defined above with at least one organic carbonate as defined above and / or at least one ionic liquid (IL) as defined above. The liquid medium (L) according to this embodiment is hereinafter called "medium (LS)".

[0057] The medium (L) in the composition (C1) may further comprise at least one metal salt (S). The term "metal salt (S)" is intended herein to mean a metal salt comprising a conductive ion.

[0058] A variety of metal salts can be used as the metal salt (S). Metal salts that are stable and soluble in the selected liquid medium (L) are generally used.

[0059] Non-limiting examples of suitable metal salts (S) include, inter alia, MeI, Me(PF6), n , Me(BF4) n , Me(CIO4) n , Me(bis(oxalato)borate) n ("Me (BOB) n ”), MeCF3SO3, Me[N(CF3SO2)2] n , Me[N(C2F5SO2)2] n , RF Me[N(CF3SO2)(R F SO2)] n , Me(AsF6) n , Me[C(CF3SO2)3] n , Me2S n (In the formula, Me is a metal, preferably a transition metal, an alkali metal or an alkaline earth metal, more preferably, Me is Li, Na, K or Cs, n is the valence of the metal, and typically, n is 1 or 2.)

[0060] Preferred metal salts (S) are the following: LiI, LiPF6, LiBF4, LiClO4, lithium bis(oxalato)borate ("LiBOB"), LiCF3SO3, LiN(CF3SO2)2 ("LiTFSI"), LiN(C2F5SO2)2, R F M[N(CF3SO2)(R F SO2)] n , LiAsF6, LiC(CF3SO2)3, Li2S n and combinations thereof.

[0061] The medium (L) in the composition (C1) may further comprise one or more additives.

[0062] When one or more additives are present in the liquid medium, non-limiting examples of suitable additives include, among others, those that are soluble in the liquid medium.

[0063] The concentration of polymer (F) in the medium (L) of composition (C1) is advantageously less than 40% and better still less than 20%.

[0064] In step (ii) of the method of the present invention, the composition (C1) is a compound represented by the formula (I): X 4-m AY m (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. is contacted with at least one first metal compound [compound (M1)] of the formula (I).

[0065] The polymer (F) and the metal compound (M1) are typically reacted at a temperature comprised between 20°C and 250°C.

[0066] A person skilled in the art will appropriately select the temperature depending on the boiling point of the medium (L) and the equipment and techniques used for the reaction in the process.

[0067] In step (ii) of the process of the invention, composition (C1) advantageously further comprises at least one catalyst.

[0068] The catalyst for the grafting reaction between the polymer (F) and the metal compound (M1) is preferably selected from the group consisting of organoaluminum compounds, such as aluminum trifluoromethanesulfonate.

[0069] Typically, the molar amount of compound (M1) added in step (ii) corresponds to the molar amount of monomer (FPM) present in composition (C1).

[0070] In step (ii) of the process of the present invention, the catalyst is typically added to composition (C1) in an amount comprised between 0.1 mol % and 50 mol %, preferably between 0.3 mol % and 20 mol %, more preferably between 0.5 mol % and 10 mol %, based on the total molar amount of compound (M1).

[0071] In step (ii), at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) react with at least a portion of the compound (M1), thereby forming -AY m A composition [composition (C2)] is obtained which comprises at least one grafted fluoropolymer [polymer (Fj)] having pendant groups.

[0072] In step (iii) of the process, the composition (C2) obtained in step (ii) is contacted with a metal compound (M2).

[0073] Compound (M2), which is different from compound (M1), is a compound of formula (II): X' 4-m’ A'Y' m’ (II) (wherein m' is an integer from 1 to 4, A' is a metal selected from the group consisting of Si, Ti, and Zr, each occurrence of Y' is a hydrolyzable group, and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX) of monomer (FPM).

[0074] Non-limiting examples of functional groups (FX') include, inter alia, carboxylic acid groups (in the form of their acids, esters, amides, anhydrides, salts or halides), sulfonic acid groups (in the form of their acids, esters, salts or halides), hydroxyl groups, phosphoric acid groups (in the form of their acids, esters, salts or halides), thiol groups, amine groups, quaternary ammonium groups, ethylenically unsaturated groups (such as vinyl groups), cyano groups, urea groups, organosilane groups, aromatic groups.

[0075] Preferably, X' in the metal compound (M2) is a C1 to C 18 More preferably, X' in the metal compound (M2) is selected from the group consisting of C1 to C6 hydrocarbon groups, optionally containing one or more functional groups. 12 It is a hydrocarbon group, optionally containing one or more functional groups.

[0076] The choice of hydrolyzable group Y of the metal compound of formula (I) is not particularly limited, provided that it is capable of forming an -OA≡ bond under appropriate conditions, and said hydrolyzable group may in particular be a halogen (especially a chlorine atom), a hydrocarboxy group, an acyloxy group or a hydroxyl group.

[0077] Examples of functional metal compounds (M2) are in particular vinyltriethoxysilane, vinyltrimethoxysilane, vinyltrismethoxyethoxysilane of formula CH2=CHSi(OC2H4OCH3)3, vinyltrismethoxyethoxysilane of formula: [ka] 2-(3,4-epoxycyclohexylethyltrimethoxysilane), formula: [ka] glycidoxypropylmethyldiethoxysilane, formula: [ka] glycidoxypropyltrimethoxysilane, formula: [ka] methacryloxypropyltrimethoxysilane, formula: [ka] of aminoethylaminopropylmethyldimethoxysilane, Formula:H2NC2H4NHC3H6Si(OCH3)3 aminoethylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-chloroisobutyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, n-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, (3-acryloxypropyl)dimethylmethoxysilane, (3-acryloxypropyl)methyldichlorosilane, (3-acryloxypropyl)methyldimethoxysilane, 3-(n-allylamino)propyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrichlorosilane, carboxyethylsilanetriol and its sodium salt, the formula: [ka] triethoxysilylpropylmaleamic acid, 3-(trihydroxysilyl)-1-propane-sulfonic acid of the formula HOSO2-CH2CH2CH2-Si(OH)3, N-(trimethoxysilylpropyl)ethylene-diaminetriacetic acid and its sodium salt of the formula: [ka] 3-(triethoxysilyl)propylsuccinic anhydride, Acetamidopropyltrimethoxysilane of formula H3C-C(O)NH-CH2CH2CH2-Si(OCH3)3, formula Ti(A) X (OR) Y where A is an amine substituted alkoxy group, such as OCH2CH2NH2, R is an alkyl group, and x and y are integers such that x+y=4.

[0078] Examples of non-functional compounds (M2) are in particular triethoxysilane, trimethoxysilane, tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-isobutyl titanate, tetra-tert-butyl titanate, tetra-n-pentyl titanate, tetra-n-hexyl titanate, tetraisooctyl titanate, tetra-n-lauryl titanate, tetra Ethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-sec-butyl zirconate, tetra-tert-butyl zirconate, tetra-n-pentyl zirconate, tetra-tert-pentyl zirconate, tetra-tert-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, and tetra-n-stearyl zirconate.

[0079] The amount of compound (M2) added in step (iii) of the process is usually comprised between 1% and 90% by weight relative to the total weight of monomer (M1) and polymer (F).

[0080] Compound (M2) may suitably be added to the reaction mixture obtained in step (ii) in the form of a solid compound or in admixture with an aqueous medium (A), possibly containing an acid catalyst as defined hereinafter.

[0081] The term "aqueous medium" is intended herein to mean a liquid medium comprising water, which is in the liquid state at 20° C. at atmospheric pressure.

[0082] The aqueous medium (A) more preferably consists of water and one or more alcohols. The alcohol contained in the medium (A) is preferably ethanol.

[0083] Step (iii) can be carried out in the same equipment and under the same temperature and concentration conditions as those used in step (ii).

[0084] All details given above for the process conditions of step (ii) are applicable here to define step (iii).

[0085] In step (iii), at least a part of the compound (M2) is -AY of the polymer (Fj). m reacts with at least a portion of the pendant groups; By that -A'Y' m A composition [composition (C3)] is obtained that comprises at least one grafted fluoropolymer [polymer (Fg)] having pendant groups.

[0086] The compound (M2) can further react with the remaining portion of the group (FX) of the monomer (FPM) of the polymer (F).

[0087] The possible reactivity of compound (M2) with the residual moieties of groups (FX) of monomers (FPM) of polymer (F) depends on the reaction conditions and the liquid medium used in the previous step.

[0088] In step (iv) of the process of the present invention, the pendant groups -A'Y'm of the polymer (Fg) undergo hydrolysis and / or condensation, thereby obtaining a composition [composition (C4)] comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] comprising fluoropolymer domains and inorganic domains.

[0089] It will be appreciated that the hydrolysis and / or condensation reaction of step (iv) may have already been initiated in situ during step (ii) of the process of the present invention and may be continued during any one of steps (iii) and (iv) of the process of the present invention.

[0090] As will be appreciated by those skilled in the art, hydrolysis and / or condensation usually produce low molecular weight by-products which may be inter alia water or alcohols depending on the nature of compound (M1) and, optionally, the nature of compound (M2).

[0091] An acid catalyst is typically added to the composition in either step (iii) or (iv) of the process of the invention.

[0092] The selection of the acid catalyst is not particularly limited. The acid catalyst is typically selected from the group consisting of organic acids and inorganic acids.

[0093] The acid catalyst is typically added to the composition of either one of steps (iii) or (iv) of the method of the present invention in an amount comprised between 0.01% and 100% by weight, preferably between 0.5% and 60% by weight, based on the total weight of composition (M2).

[0094] The acid catalyst is preferably selected from the group consisting of organic acids such as citric acid, acetic acid, and formic acid.

[0095] Very good results have been obtained with formic acid and citric acid.

[0096] In one embodiment of the present invention, steps (ii) and (iii) are carried out simultaneously.

[0097] The term "concurrently" intends that metal compound (M1) and metal compound (M2) are added together to composition (C1).

[0098] Without being bound by this theory, the applicant believes that under the reaction conditions, the group (FX) of the monomer (FPM) of the polymer (F) first reacts with the metal compound (M1), resulting in the formation of -AY m At least one grafted fluoropolymer having pendant groups [polymer (Fj)] is obtained, and then at least a portion of compound (M2) is grafted to the -AY group of polymer (Fj). m It is believed that the fluoropolymer reacts with at least a portion of the pendant groups, thereby obtaining a composition [composition (C4)] comprising at least one grafted fluoropolymer [polymer (Fg)] having -A'Y'm pendant groups.

[0099] According to another embodiment of the present invention, steps (ii) and (iii) are carried out sequentially.

[0100] According to said embodiment of the invention, after step (ii), the polymer (Fj) can be isolated from the composition (C2). In this embodiment, the -AY m The composition (C2) comprising at least one grafted fluoropolymer having pendant groups (polymer (Fj)) may further be subjected to a step (iib): (iib) isolating the fluoropolymer [polymer (Fj)] as a solid by filtering the composition (C2), washing the solid with a polar solvent and drying to recover the dry polymer (Fj). can be received.

[0101] The polar solvent used for washing is appropriately selected from solvents that cannot solubilize the polymer (Fj). The polar solvent can typically be selected from alcohols.

[0102] In step (v) of the process of the invention, the polymer (Fj) after filtration and washing is dried, typically at a temperature comprised between 25°C and 200°C.

[0103] Drying can be carried out at atmospheric pressure or under vacuum, or it can be carried out under a controlled atmosphere, for example an inert gas, typically especially devoid of moisture (water vapor content less than 0.001% v / v).

[0104] The polymer (Fj) formed during the process, which is an intermediate in the process for preparing said polymer (Fh), is novel and forms a further aspect of the invention.

[0105] Thus, in one aspect, the invention provides a grafted fluoropolymer [polymer (Fj)] obtained by a process comprising the following steps: (i) preparing a composition [composition (C1)] comprising a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], said polymer (F) being - repeat units derived from at least one fluorinated monomer [monomer (FM)]; - repeat units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl, amine, carboxyl, thiol and anhydride; (ii) Composition (C1) is treated with at least a first metal compound of formula (I) [compound (M1)]: X 4-m AY m (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. to react at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY m obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (Fj)] having pendant groups; (iib) isolating the fluoropolymer [polymer (Fj)] as a solid by filtering composition (C2), washing the solid with a polar solvent and drying to recover the dry polymer (Fj).

[0106] The polymer (Fj) obtained in step (iib) of the process of the present invention can be further ground and isolated as a powder component for further use.

[0107] According to a first variant [variant (A)] of the method for producing a fluoropolymer hybrid organic / inorganic composite [polymer (Fg)], the medium (L) in the composition (C1) is the medium (LS) defined above.

[0108] The composition (C4) obtained at the end of step (iv) of variant (A) then comprises a polymer (Fg) and at least one organic solvent (S).

[0109] According to a second variant [variant (B)] of the process for preparing a fluoropolymer hybrid organic / inorganic composite [polymer (Fg)], the medium (L) in the composition (C1) obtained in step i) does not comprise a solvent (S) as defined above.

[0110] The composition (C4) obtained at the end of step (iv) of variant (B) then comprises the polymer (Fg) and the liquid medium (L) free of organic solvents (S).

[0111] In another object, the present invention provides a fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] according to the present invention.

[0112] The present invention therefore further relates to a method for producing a fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)], said method comprising the following steps: (i) preparing a composition [composition (C1)] comprising a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], said polymer (F) being - repeat units derived from at least one fluorinated monomer [monomer (FM)]; - repeat units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl, amine, carboxyl, thiol and anhydride; (ii) Composition (C1) is treated with at least a first metal compound of formula (I) [compound (M1)]: X 4-m AY m (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. to react at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY m obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (Fj)] having pendant groups; (iii) Composition (C2) is treated with at least one second metal compound of formula (II) different from compound (M1) [compound (M2)]: X' 4-m’ A'Y' m’ (II) wherein m' is an integer from 1 to 4, A' is a metal selected from the group consisting of Si, Ti, and Zr, each occurrence of Y' is a hydrolyzable group, and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX). to contact at least a portion of the compound (M2) with -AY of the polymer (Fj). m reacting with at least a portion of the pendant groups; This results in -A'Y' m obtaining a composition [composition (C3)] comprising at least one grafted fluoropolymer [polymer (Fg)] having pendant groups; and (iv) -A'Y' of polymer (Fg) m hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4)] comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)]; (v) processing the composition (C4) comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)] as defined above into a film; and (vi) drying the film obtained in step (v).

[0113] For purposes of the present invention, the term "film" is intended to mean a continuous, generally thin sheet.

[0114] When the process for obtaining the polymer (Fh) is carried out according to variant (A) defined above, the composition (C4) obtained at the end of step (iv) comprises at least one organic solvent (S), said composition (C4) being suitable for casting to produce thin films using any standard casting method.

[0115] Thus, when composition (C4) is obtained according to variant (A), the processing of said composition (C4) into a film in step (v) is typically carried out using techniques generally known in the art.

[0116] Non-limiting examples of suitable techniques include casting, doctor blade coating, metering rod (or Meyer rod) coating, slot die coating, knife over roll coating or "gap" coating, and the like.

[0117] According to variant (A) of the process of the invention, in step (vi), the film obtained in step (v) is dried, typically at a temperature comprised between 25°C and 200°C.

[0118] Drying can be carried out at atmospheric pressure or under vacuum, or it can be carried out under a controlled atmosphere, for example an inert gas, typically especially devoid of moisture (water vapor content less than 0.001% v / v).

[0119] The drying temperature will be selected such that the solvent (S) in the medium (L) provided in step (iv) of the method of the invention is removed by evaporation.

[0120] When the process for obtaining the polymer (Fh) is carried out according to variant (B) defined above, the composition (C4) obtained at the end of step (iv) is free of solvent (S).

[0121] According to said variant (B), steps (i) to (iv) of the process of the invention can be suitably carried out in a closed apparatus such as a reactor or in a semi-closed apparatus such as an extruder. In both said cases, the reactions of steps (i) to (iv) are carried out at elevated temperature in the presence of the polymer (F) in the molten state dissolved in the liquid medium (L).

[0122] The residence time in the closed equipment depends on the equipment used and the reactivity of the system. Those skilled in the art will choose the appropriate timing to complete the reaction. The advantage of the closed equipment is that the residence time can be selected from a few minutes to a few hours or days. This is not possible in semi-closed equipment such as extruders. The following examples will illustrate this case.

[0123] When steps (i) to (iv) are carried out in a semi-closed apparatus such as an extruder, the reaction time will be adjusted to the structure and revolutions per minute (rpm) of the apparatus. The residence time in a semi-closed apparatus such as an extruder is typically less than 10 minutes, preferably less than 5 minutes.

[0124] According to said variant (B), when steps (i) to (iv) are carried out in a closed apparatus, composition (C4) can be processed into a film in step (v) by compression molding or in an extruder. In both cases, composition (C4) removed from the closed apparatus at the end of step (iv) is preferably comminuted before being subjected to step (v).

[0125] According to variant (B), when steps (i) to (iv) are carried out in a semi-closed apparatus, steps (v) and (vi) can be carried out in the same apparatus and thus the film can be obtained directly from the extruder die, or the material leaving the semi-closed apparatus can be fed to a second extruder specially designed to obtain high quality films or polymer electrolyte membranes.

[0126] In the process for producing a film of fluoropolymer hybrid organic / inorganic composite [polymer (Fh)], an additional step of co-laminating the film obtained after step (v) or (vi) according to any of the variants defined above can be applied to reduce the thickness of the film.

[0127] The film of fluoropolymer hybrid organic / inorganic composite [polymer (Fh)] preferably has a thickness in the range of 5 to 300 microns, preferably 10 to 50 microns.

[0128] In the process for producing a film of fluoropolymer hybrid organic / inorganic composite [polymer (Fh)], an additional post-treatment step can be applied to the film obtained after step (vi) or optionally after co-lamination, in order to complete the crosslinking, which is usually already initiated in the previous steps of the process. Said crosslinking post-treatment comprises contacting said film with an acid catalyst as defined above. Contacting the film with the acid catalyst can be suitably carried out in an acid catalyst saturated atmosphere for a time sufficient to complete the crosslinking.

[0129] Alternatively, the crosslinking post-treatment can include heat treatment under pressure, such as at a pressure of about 8-12 MPa and a temperature in the range of 80° C.-120° C. for 2-10 minutes. Post-treatment can also be performed with a hot calender, which may or may not reduce the thickness of the film.

[0130] In a further alternative, post-crosslinking can be achieved by exposing the film to microwave radiation.

[0131] In step (i) of the method of the present invention, composition (C1) may further comprise an electrolyte medium [medium (E)] comprising at least one metal salt.

[0132] In the process for producing a film according to the invention, when the medium (E) is present in the composition (C1), the film obtained by the process defined above is suitable for producing a polymer electrolyte membrane. The composition (C1) according to this embodiment is hereinafter referred to as "composition (C5)".

[0133] Therefore, in another aspect, the present invention relates to a polymer electrolyte membrane obtainable by the process of the present invention.

[0134] For purposes of the present invention, the term "membrane" is intended to indicate a discrete, generally thin, interface that mitigates the permeation of chemical species in contact therewith.

[0135] Thus, in one aspect, the present invention provides a method for producing a polymer electrolyte membrane, said method comprising: (i) preparing a composition [composition (C5)] comprising a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], said polymer (F) being - repeat units derived from at least one fluorinated monomer [monomer (FM)]; - repeat units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl, amine, carboxyl, thiol and anhydride, the liquid medium (L) also containing at least one metal salt (S); (ii) Composition (C5) is treated with at least a first metal compound of formula (I) [compound (M1)]: X 4-m AY m (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. to react at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AYm obtaining a composition [composition (C2')] comprising at least one grafted fluoropolymer having pendant groups [polymer (Fj)]; (iii) mixing the composition (C2′) at least one second metal compound of formula (II) different from compound (M1) [compound (M2)]: X' 4-m’ A'Y' m’ (II) wherein m' is an integer from 1 to 4, A' is a metal selected from the group consisting of Si, Ti, and Zr, each occurrence of Y' is a hydrolyzable group, and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX'). to contact at least a portion of the compound (M2) with -AY of the polymer (Fj). m reacting with at least a portion of the pendant groups; As a result, -A'Y' <2945 m obtaining a composition [composition (C3')] comprising at least one grafted fluoropolymer having pendant groups [polymer (Fg)]; (iv) Polymer (Fg) -A'Y' < 2957 m hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4')] comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)]; (v) processing the composition (C4') into a film; and (vi) drying the film obtained in step (v).

[0136] All the details and features described above for the production process of a film of a fluoropolymer hybrid organic / inorganic composite [polymer (Fh)] can be applied here to define the production process of the polymer electrolyte membrane of the invention.

[0137] The polymer electrolyte membranes of the present invention advantageously possess outstanding crosslink density characteristics, which allow them to exhibit excellent mechanical properties that make them suitable for use as free-standing polymer electrolyte membranes.

[0138] The crosslink density of the fluoropolymer hybrid organic / inorganic composite of the present invention can be measured by any suitable method. The fluoropolymer hybrid organic / inorganic composite is typically swollen in a suitable solvent at a specific temperature and either the change in mass or the change in volume is measured.

[0139] Surprisingly, it has been found that the free-standing polymer electrolyte membranes of the present invention are capable of stably containing and retaining a high percentage of electrolyte while maintaining outstanding mechanical properties and excellent ionic conductivity properties.

[0140] In a further aspect, the present invention relates to an electrochemical device comprising the polymer electrolyte membrane of the present invention.

[0141] Non-limiting examples of suitable electrochemical devices include, inter alia, secondary batteries, particularly alkaline or alkaline earth secondary batteries such as lithium ion batteries, and capacitors, particularly lithium ion capacitors.

[0142] To the extent that the disclosures of any patents, patent applications, and publications incorporated herein by reference conflict with the statements in this application to the extent that any term may be unclear, the statements herein shall control.

[0143] The invention will now be described in more detail with reference to the following examples, the purpose of which is merely illustrative and not intended to limit the scope of the invention. EXAMPLES

[0144] Experimental section raw materials Polymer (F-1): VDF / HEA (0.4 mol%) / HFP (2.5 mol%) copolymer with an intrinsic viscosity of 0.11 l / g in DMF at 25° C. Polymer (F-2): a VDF-AA (0.9 mol %)-HFP (2.4 mol %) polymer having a viscosity of 0.30 l / g in DMF at 25° C. Epoxysilane (EPP-1): [3-(2,3-epoxypropoxy)propyl]trimethoxysilane. Epoxysilane (EPP-2): [3-(2,3-epoxypropoxy)propyl]triethoxysilane. Catalyst (ATS): Aluminum trifluoromethanesulfonate. LiTFSI: bis(trifluoromethanesulfonyl)imide lithium salt. Medium (EL-1): ethylene carbonate (EC) / propylene carbonate (PC) (weight ratio 1 / 1). Medium (EL-2): A solution of LiTFSI (1 mol / L) in ethylene carbonate (EC) / propylene carbonate (PC) (weight ratio 1 / 1). TEOS:Si(OC2H5)4

[0145] Basic steps for preparing extrusion material in a semi-closed apparatus: A 15 ml twin screw extruder (DSM Xplore) (Miniextruder) was used. All tests were performed at 100 rpm. The residence time in all tests was 2 minutes.

[0146] Basic steps for producing films by compression molding: The films were obtained by compression moulding using a Collin P200T press. The material is heated to 90°C and pressed at 0 bar for 3 minutes. The press is then evacuated and set at 100 bar pressure for 2 minutes at 90°C. The press is then cooled and opened at approximately 30-40°C.

[0147] Determination of the intrinsic viscosity of the polymer (F) The intrinsic viscosity (η) [dl / g] was calculated based on the fall time at 25° C. of a solution obtained by dissolving the polymer (F) in N,N-dimethylformamide at a concentration of about 0.2 g / dl using an Ubbelhode viscometer, according to the following formula:

number

[0148] Dissolution Test Approximately 5-10 mg of membrane sample was placed in approximately 10 mL of N,N-dimethylformamide (DMF) at room temperature for 60 min.

[0149] DMF is a very good solvent for the polymer (F). The higher the crosslink density of the film, the more swelling and less dissolution of the film can be achieved in DMF. Conversely, a poorly crosslinked film will dissolve most of the film in DMF.

[0150] Example 1 - Preparation of fluoropolymer film using F-1 by solvent casting (variant A) Polymer (F-1) (0.8 g) was dissolved in 7.2 g of acetone at room temperature, thereby obtaining a solution containing 10 wt% of polymer (F-1). The solution was homogeneous. Then, 2.8 g of EL-1, 6.4 mg of ATS, and 0.16 g of EPP-1 were added to this solution in this order. The solution was mixed for about 10 minutes, and 1.38 g of TEOS and 0.76 g of formic acid were added. It was then poured into a 80 x 15 mm Petri dish and placed in a hood at room temperature overnight to allow the acetone to evaporate. Afterwards, a film of about 300 microns was obtained. When tested in DMF according to the dissolution method, no dissolution was observed in DMF.

[0151] Example 2 - Preparation of fluoropolymer film using F-2 by solvent casting (Variant A) The same procedure as in Example 1 was followed, but using F-2 polymer and EPP-2 (same amount as EPP-1 in Example 1). After that, a film of about 300 microns was obtained. It was tested in DMF according to the dissolution method, and no dissolution was observed in DMF.

[0152] Comparative Example 1 by Solvent Casting A film was prepared according to the same procedure as in Example 1, but without the incorporation of EPP-1 and ATS. This film was dissolved in DMF in a dissolution test.

[0153] Example 3 - Preparation of fluoropolymer film using F-1 by processing in the melt (variant B) The reactions were carried out in a Büchiglaster reactor Novoclave with the following characteristics: Novoclave - Laboratory High Pressure / High Temperature Reactor (HPHT) from Buechiglasuster. Reactor volume: 100-600ml, pressure: up to 1500bar, temperature: -20°C to +500°C. Electric heating with built-in automatic tap water cooling and programmable PID control for fast and precise temperature control. Magnetic stirrer drive ensures efficient mixing and stirring of the process medium as well as excellent heat transfer. Material: Stainless steel.

[0154] The following components were fed into the reactor: polymer (F-1) (9.6 g), EL-1 (33.6 g), ATS (6.4 mg), EPP-1 (0.64 g), and finally a homogeneous solution formed by TEOS (16.56 g), water (5.74 g), ethanol (4.14 g), and citric acid (0.22 g) was added. The reactor was then brought to 110° C. and held at that temperature for 24 hours with stirring at 1000 rpm. Afterwards, it was removed from the reactor and the product obtained was ground and dried at 40° C. for 1 hour. A portion of this material was fed into a mini-extruder as defined above and processed at 90° C. The extruded material obtained was compression molded with the equipment and conditions mentioned above. A film of about 100 microns was then obtained. When tested in DMF, no dissolution was observed in DMF.

[0155] Example 4 - Preparation of fluoropolymer film using F-2 by melt processing The same procedure was followed as in Example 3, but with F-2 polymer and EPP-2 instead of EPP-1. Extrusion in a mini extruder was carried out at 110°C instead of 90°C. A film of about 100 microns was then obtained. Tested in DMF according to the dissolution method, no dissolution was observed in DMF.

[0156] Comparative Example 2 by Processing in the Melt State A film was prepared according to the same procedure as in Example 3, but without the incorporation of EPP-1 and ATS. The film was dissolved in DMF.

[0157] Example 5 - Preparation of fluoropolymer film using F-1 by melt processing The following components were placed in the reactor described above: polymer (F-1) (9.6 g), EL-1 (33.6 g), ATS (6.4 mg), EPP-1 (0.64 g). The reactor was then brought to 90° C. and held at that temperature for 30 minutes while stirring at 1000 rpm. The reactor was then cooled to 50° C. and the following homogeneous solution formed from TEOS (16.56 g), water (5.74 g), ethanol (4.14 g), and citric acid (0.22 g) was placed in. The reactor was then brought to 110° C. again and held at that temperature for 24 hours while stirring at 1000 rpm. Afterwards, the reactor was removed and the product obtained was ground and dried at 40° C. for 1 hour. A portion of this material was fed to the mini-extruder described above and processed at 90° C. The extruded material obtained was compression molded with the equipment and conditions described above. A film of about 100 microns was then obtained. When tested in DMF, no dissolution was observed in DMF.

[0158] Comparative Example 3 by Processing in the Melt State The film was prepared according to the same procedure as in Example 4, but without the incorporation of EPP-2 and ATS. The film was dissolved in DMF.

[0159] Example 6 - Preparation of fluoropolymer (Fj) using F-2 by processing in the melt The following ingredients were placed in the reactor described above: Polymer (F-2) (9.6 g), EL-1 (33.6 g), ATS (6.4 mg), EPP-2 (0.64 g). The reactor was then brought to 110° C. and held at that temperature for 4 hours while stirring at 1000 rpm. The reactor was then removed and the product was dried at 70° C. for 48 hours.

[0160] Example 7 - Preparation of fluoropolymer (Fj) using F-2 by processing in the melt The following ingredients were placed in the reactor described above: polymer (F-2) (9.6 g), EL-2 (33.6 g), ATS (6.4 mg), EPP-2 (0.64 g), and finally a homogeneous solution formed by TEOS (16.56 g), water (5.74 g), ethanol (4.14 g), and citric acid (0.22 g). The reactor was then brought to 110° C. and kept at that temperature for 24 hours with stirring at 1000 rpm. Afterwards, it was removed from the reactor, and the product obtained was ground and dried at 40° C. for 1 hour. A portion of this material was fed to the mini-extruder described above and processed at 110° C. The extruded material obtained was compression molded using the equipment and conditions described above. A film of about 100 microns was then obtained. When tested in DMF, no dissolution was observed in DMF.

[0161] Because the film contains metal salts, the membrane itself is ionically conductive.

[0162] Example 8 - Preparation of fluoropolymer film using F-2 by melt processing followed by curing The following components were fed into the reactor described in Example 3 (Novoclave from Büchiglasuster) as follows: polymer (F-2) (9.6 g), EL-1 (33.6 g), ATS (6.4 mg), EPP-2 (0.64 g), and finally a homogeneous solution formed by TEOS (16.56 g), water (5.74 g), ethanol (4.14 g), and citric acid (0.22 g). Then, removed from the reactor, the product obtained was ground, dried at 40° C. for 1 h, and then ground to a powder. This process was repeated several times (at least 6 times) to obtain enough material to feed the extruder. A co-rotating twin screw extruder (Leistritz ZSE 18HP, screw diameter D 18 mm, screw length 720 mm (40 D)) was used. The extruder was equipped with a main feeder, a secondary feeder, and a degassing unit. The barrel consisted of eight temperature control zones and one cooling zone (at the feeder) that allowed the desired temperature profile to be set. The molten polymer was extruded through a die consisting of a flat shape with a thickness of 1 mm and a length of 40 mm. The extrudate was stretched between two cold cylinders with a diameter of 100 mm and a width of 100 mm, with a gap of 100 to 500 μm. The extrudate was cooled in air. The temperature profile was set at 110 °C in all heating zones and the rotation speed of the extruder was adjusted to 250 rpm.

[0163] After that, a film of 100 to 300 microns was obtained.

[0164] Film samples were post-treated either by processing in a press at 90 °C for 2–5 min at 10 MPa pressure to simulate a heated calendar to obtain a hardened extruded film, or by microwave processing at 800 W for 30 s.

[0165] Film samples without post-treatment (uncured extruded film) were almost completely dissolved in DMF, whereas no dissolution was observed for the cured extruded film. Tensile tests were performed at room temperature on uncured and cured extruded films (1 cm x 4 cm) with a gauge length of 20 mm using an Instrom 5966 machine equipped with 250 N pneumatic grips. A 2 kN load cell (error <0.25%) was used, with the measurement parameters being a strain rate of 1 mm / min.

[0166] Three specimens were used for each formulation, and the average values ​​and corresponding standard deviations of Young's modulus, stress at break, and elongation at break were calculated and reported in Table 1.

[0167] [Table 1]

[0168] Preparation of fluoropolymer film using Example 9-F-2; alternative processing in the melt (a) The following ingredients were placed in a reactor: EL-1 (20 g), TEOS (16.56 g), water (5.74 g), ethanol (4.14 g), and citric acid (0.22 g). The reactor was then brought to 110° C. and held at that temperature for 24 hours with stirring at 1000 rpm. The reactor was then removed and the resulting product was ground and dried at 40° C. for 1 hour. (b) The following ingredients: EL-1 (10.64 g), ATS (14.2 mg), EPP-2 (1.42 g), and polymer (F-2) (7.09 g) were placed in a mini-extruder (DSM Xplore, as described above) at 110° C. The resulting product was pelletized in a VariCut pelletizer (Thermo Fisher Scientific). (c) The products obtained from step (a) and step (b) were fed by two different feeders to a single inlet feeder and extruded as done in Example 8 detailed above. Afterwards, a film of about 100-200 microns was obtained.

[0169] Film samples were post-treated either by processing in a press at 90 °C for 2–5 min at 10 MPa pressure to simulate a heated calendar to obtain a hardened extruded film, or by microwave processing at 800 W for 30 s.

[0170] Film samples without post-treatment (uncured extruded film) were almost completely dissolved in DMF, whereas no dissolution was observed for the cured extruded film. Tensile tests were performed at room temperature on uncured and cured extruded films (1 cm x 4 cm) with a gauge length of 20 mm using an Instrom 5966 machine equipped with 250 N pneumatic grips. A 2 kN load cell (error <0.25%) was used, with the measurement parameters being a strain rate of 1 mm / min.

[0171] The uncured extruded film dissolved almost completely in DMF, whereas no dissolution was observed in the cured extruded film.

[0172] Uncured and cured extruded films (1 cm x 4 cm) were subjected to tensile testing as described in Example 8. The mean and standard deviations of Young's modulus, stress at break, and elongation at break are reported in Table 2.

[0173] [Table 2]

[0174] Example 10 - Preparation of fluoropolymer film using F-2 by alternative processing in the melt The following ingredients: EL-1 (13.79 g), ATS (2.6 mg), EPP-2 (0.26 g), and polymer (F-2) (3.94 g) were fed into a mini-extruder (DSM Xplore, as described above) at 110° C. The resulting product was pelletized with a VariCut pelletizer (Thermo Fisher Scientific).

[0175] The pelletized intermediate (29.45 g) and the following ingredients were placed in a reactor: TEOS (12.56 g), water (4.35 g), ethanol (3.14 g), and citric acid (0.17 g). The reactor was brought to 110° C. and held at that temperature for 6 hours with stirring at 1000 rpm. Afterwards, the reactor was removed and the resulting product was ground and dried at 40° C. for 1 hour. This material was fed into the mini-extruder described above and processed at 110° C. The resulting extruded material was compression molded using the equipment and conditions described above. A film of about 100 microns was then obtained and tested in DMF. No dissolution of the polymer was observed.

Claims

1. A method for producing a fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)], comprising the steps of: (i) preparing a composition [composition (C1)] containing a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], wherein the polymer (F) is repeat units derived from at least one fluorinated monomer [monomer (FM)], - repeating units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl groups, amines, carboxyls, thiols and anhydrides; a process comprising: (ii) Composition (C1) is mixed with at least a first metal compound [compound (M1)] of formula (I): X ４－ｍ AY ｍ (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. and reacting at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY ｍ obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (F-j)] having pendant groups; (iii) Composition (C2) is prepared by adding at least a second metal compound of formula (II) different from compound (M1) [compound (M2)]: ︸' ４－ｍ’ _'] ｍ’ (=) wherein m' is an integer from 1 to 4; A' is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y' is a hydrolyzable group; and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX). to contact at least a portion of the compound (M2) with the -AY of the polymer (Fj). ｍ reacting with at least a portion of the pendant groups; Thereby, -A'Y' ｍ Obtaining a composition [composition (C3)] comprising at least one grafted fluoropolymer [polymer (Fg)] having pendant groups; and (iv) -A'Y' in polymer (Fg) ｍ hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4)] comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)]. A method comprising:

2. The monomer (FPM) has the formula (III): 【Chemistry 1】 (In the formula, R １ , R ２ and R ３ are equal to or different from each other, and are a hydrogen atom and C １ ~C ３ are independently selected from hydrocarbon groups; R Ｘ is a C containing at least one functional group [group (FX)] selected from the group consisting of a hydroxyl group, an amine, a carboxylic acid group, a thiol group, and an anhydride group; １ ~C ２０ hydrocarbon moiety) The method of claim 1, wherein the hydrogenated monomer is

3. The monomer (FPM) is represented by formula (IV): 【Chemistry 2】 (In the formula, R １ , R ２ and R ３ are equal to or different from each other, and are a hydrogen atom and C １ ~C ３ R is independently selected from hydrocarbon groups; Ｈ is a hydrogen atom or at least one functional group selected from the group consisting of a hydroxyl group, an amine, a carboxyl group, a thiol group, and an anhydride group [group (FX Ｈ ) )] １ ~C ２０ hydrocarbon portion) The method of claim 2, wherein the (meth)acrylic monomer is selected from the group consisting of:

4. 4. The method according to any one of claims 1 to 3, wherein the monomer (FPM) is selected from the group consisting of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyethylhexyl (meth)acrylate, acrylic acid (AA), and succinic acid 1-[2-(acryloyloxy)propyl] ester.

5. 4. The method according to any one of claims 1 to 3, wherein the monomer (FM) is selected from the group consisting of vinylidene fluoride (VDF), tetrafluoroethylene (TFE), and chlorotrifluoroethylene (CTFE).

6. 4. The method according to any one of claims 1 to 3, wherein the polymer (F) is semi-crystalline and has an intrinsic viscosity, measured in dimethylformamide at 25°C, comprised between 0.05 l / g and 0.80 l / g, more preferably between 0.10 l / g and 0.50 l / g, even more preferably between 0.2 l / g and 0.4 l / g.

7. The method according to any one of claims 1 to 3, wherein the medium (L) is selected from organic carbonates, ionic liquids (IL), solvents (S), or mixtures thereof.

8. 8. The method of claim 7, wherein the solvent (S) is selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphamide, dioxane, tetrahydrofuran, tetramethylurea, triethyl phosphate, trimethyl phosphate, aliphatic ketones, alicyclic ketones, and alicyclic esters.

9. The polymer (F) is (a) at least 60 mol %, preferably at least 75 mol %, more preferably at least 85 mol % vinylidene fluoride (VDF); (b) optionally 0.1 mol% to 15 mol%, preferably 0.5 mol% to 10 mol%, more preferably 1 mol% to 5 mol% of at least one monomer (FM) selected from vinyl fluoride (VF1), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), trifluoroethylene (TrFE), perfluoromethyl vinyl ether (PMVE); (c) 0.01 mol% to 10 mol%, preferably 0.05 mol% to 5 mol%, more preferably 0.1 mol% to 2 mol% of acrylic acid (AA); Including, 4. The method according to claim 1, wherein said polymer (F) has an intrinsic viscosity, measured in dimethylformamide at 25° C., comprised between 0.2 l / g and 0.4 l / g.

10. A fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] obtainable by the method according to any one of claims 1 to 3.

11. A grafted fluoropolymer [polymer (Fj)], (i) preparing a composition [composition (C1)] containing a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], wherein the polymer (F) is repeat units derived from at least one fluorinated monomer [monomer (FM)], - repeating units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl groups, amines, carboxyls, thiols and anhydrides; a process comprising: (ii) Composition (C1) is mixed with at least a first metal compound [compound (M1)] of formula (I): X ４－ｍ AY ｍ (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. and reacting at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY ｍ Obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (F-j)] having pendant groups; and (iib) isolating the fluoropolymer [polymer (Fj)] as a solid by filtering the composition (C2), washing the solid with a polar solvent and drying to recover the dry polymer (Fj). A grafted fluoropolymer [polymer (Fj)] obtained by a process comprising the steps of:

12. Fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] according to claim 11.

13. 13. The fluoropolymer film of claim 12 having a thickness in the range of 5 to 300 microns, preferably 10 to 50 microns.

14. 14. A method for producing a fluoropolymer film comprising at least one fluoropolymer hybrid organic / inorganic composite [polymer (Fh)] according to claim 12 or 13, comprising: (i) preparing a composition [composition (C1)] containing a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], wherein the polymer (F) is repeat units derived from at least one fluorinated monomer [monomer (FM)], - repeating units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl groups, amines, carboxyls, thiols and anhydrides; a process comprising: (ii) Composition (C1) is mixed with at least a first metal compound [compound (M1)] of formula (I): X ４－ｍ AY ｍ (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. and reacting at least a portion of the groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY ｍ obtaining a composition [composition (C2)] comprising at least one grafted fluoropolymer [polymer (F-j)] having pendant groups; (iii) Composition (C2) is prepared by adding at least a second metal compound of formula (II) different from compound (M1) [compound (M2)]: ︸' ４－ｍ’ _'] ｍ’ (=) wherein m' is an integer from 1 to 4; A' is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y' is a hydrolyzable group; and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX). to contact at least a portion of the compound (M2) with the -AY of the polymer (Fj). ｍ reacting with at least a portion of the pendant groups; Thereby, -A'Y' ｍ Obtaining a composition [composition (C3)] comprising at least one grafted fluoropolymer [polymer (Fg)] having pendant groups; and (iv) -A'Y' in polymer (Fg) ｍ hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4)] comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)]; (v) processing the composition (C4) comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)] obtained in step (iv) into a film; and (vi) drying the film obtained in step (v); A method comprising:

15. A method for producing a polymer electrolyte membrane, comprising: (i) preparing a composition [composition (C5)] containing a liquid medium [medium (L)] and at least one fluoropolymer [polymer (F)], wherein the polymer (F) is repeat units derived from at least one fluorinated monomer [monomer (FM)], - repeating units derived from at least one monomer [monomer (FPM)] comprising at least one functional group [group (FX)] selected from the group consisting of hydroxyl groups, amines, carboxyls, thiols and anhydrides; Including, the liquid medium (L) also comprises at least one metal salt (S); (ii) Composition (C5) is prepared by mixing at least a first metal compound [compound (M1)] of formula (I): X ４－ｍ AY ｍ (I) wherein m is an integer from 1 to 3; A is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y is a hydrolyzable group; each occurrence of X is a hydrocarbon group; and at least one X contains at least one epoxy functional group. and reacting at least a portion of said groups (FX) of the monomers (FPM) of the polymer (F) with at least a portion of the compound (M1), thereby forming -AY ｍ obtaining a composition [composition (C2')] comprising at least one grafted fluoropolymer [polymer (Fj)] having pendant groups; (iii) The composition (C2′) is prepared by adding at least a second metal compound of formula (II) [compound (M2)] different from compound (M1): ︸' ４－ｍ’ _'] ｍ’ (=) wherein m' is an integer from 1 to 4; A' is a metal selected from the group consisting of Si, Ti, and Zr; each occurrence of Y' is a hydrolyzable group; and each occurrence of X' is a hydrocarbon group, optionally containing at least one functional group [group (FX')] different from group (FX). to contact at least a portion of the compound (M2) with the -AY of the polymer (Fj). ｍ reacting with at least a portion of the pendant groups; Thereby, -A'Y' ｍ obtaining a composition [composition (C3')] comprising at least one grafted fluoropolymer [polymer (Fg)] having pendant groups; (iv) -A'Y' in polymer (Fg) ｍ hydrolyzing and / or condensing the pendant groups, thereby obtaining a composition [composition (C4')] comprising at least one fluoropolymer hybrid organic / inorganic composite material [polymer (Fh)]; (v) processing the composition (C4') into a film; and (vi) drying the film obtained in step (v); A method comprising:

16. An electrochemical device comprising the polymer electrolyte membrane of claim 15.

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