Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C317/00—Sulfones; Sulfoxides
  • C07C317/14—Sulfones; Sulfoxides having sulfone or sulfoxide groups bound to carbon atoms of six-membered aromatic rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C323/00—Thiols, sulfides, hydropolysulfides or polysulfides substituted by halogen, oxygen or nitrogen atoms, or by sulfur atoms not being part of thio groups
  • C07C323/01—Thiols, sulfides, hydropolysulfides or polysulfides substituted by halogen, oxygen or nitrogen atoms, or by sulfur atoms not being part of thio groups containing thio groups and halogen atoms, or nitro or nitroso groups bound to the same carbon skeleton
  • C07C323/09—Thiols, sulfides, hydropolysulfides or polysulfides substituted by halogen, oxygen or nitrogen atoms, or by sulfur atoms not being part of thio groups containing thio groups and halogen atoms, or nitro or nitroso groups bound to the same carbon skeleton having sulfur atoms of thio groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
  • C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
  • C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
  • C07D251/14—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with hydrogen or carbon atoms directly attached to at least one ring carbon atom
  • C07D251/24—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with hydrogen or carbon atoms directly attached to at least one ring carbon atom to three ring carbon atoms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0289—Means for holding the electrolyte
  • H01M8/0293—Matrices for immobilising electrolyte solutions
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/102—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
  • H01M8/1027—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having carbon, oxygen and other atoms, e.g. sulfonated polyethersulfones [S-PES]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/1016—Fuel cells with solid electrolytes characterised by the electrolyte material
  • H01M8/1018—Polymeric electrolyte materials
  • H01M8/102—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer
  • H01M8/1032—Polymeric electrolyte materials characterised by the chemical structure of the main chain of the ion-conducting polymer having sulfur, e.g. sulfonated-polyethersulfones [S-PES]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
  • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

• the present invention relates to the monomers that can be used for the synthesis of polymers intended in particular, in sulphonated form, to constitute a solid electrolyte or membrane in a fuel cell.
• the electrolyte typically consists of a polymer membrane PEM (abbreviation for "Polymer Electrolyte Membrane”) proton-conducting and capable of separating the reactive species, consisting of two distinct nanophases: on the one hand a hydrophobic part ensuring the mechanical integrity, waterproof and gas (3 ⁇ 4 and 0 2 ), on the other hand a sulfonated portion consisting of narrow hydrophilic channels allowing the passage of protons and thus ensuring the ionic conductivity of the battery.
• This polymer membrane is disposed between the anode and the cathode of the cell, such an assembly being commonly called “ME A” (Membrane Electrode Assembly).
• a good candidate polymeric material for a PEM fuel cell must meet very high requirements with respect to its mechanical, physical and chemical properties.
• the MEA assembly is expected to operate for thousands of hours at relatively high temperatures (60 to 100 ° C in the case of PEM batteries, up to 160 ° C in the case of DMFC methanol) while being exposed to particularly high humidity and acid pH values close to zero.
• Most of the known polymers undergo decomposition under such conditions, whether of aliphatic or aromatic type.
• Aliphatic copolymers derived from perfluorosulfonic acid commercialized for example under the name Nafion ® or Flemion ®, have been used extensively as conductive membranes in fuel cells such as hydrogen / air, hydrogen / oxygen or methanol / air.
• Nafion ® type polymers is firstly not suitable for use in fuel cells methanol type, this due to a performance reduced for the highest use temperatures, due to a significant increase in permeability of the membrane to methanol.
• a second fluorinated polymer especially a PTFE (polytetrafluoroethylene) of the expanded microporous type (or "ePTFE”).
• Nafion ® type polymers are their cost of synthesis, not to mention a basic chemistry which no longer meets the latest requirements in terms of environment, hygiene and security. - -
• polystyrene resin examples of such polymers are for example poly (arylene-ether-sulfone), sold in particular under the names “Udel”, “Radel” or poly (ether-ether-ketone) marketed for example under the name “PEEK”.
• aromatic polymers are generally poorly mixed with an ePTFE-type polymer and the resulting membranes can not therefore be easily reinforced by an ePTFE polymer, such reinforcement requiring a prior surface treatment of the ePTFE polymer by plasma or by in a very aggressive chemical environment (see, for example, article entitled “Challenging reinforced composite polymer electrolyte membranes based on disulfonated poly (arylene-ether-sulfone) -impregnated expanded PTFE for fuel cell applications", Xiaobing Zhu et al., J. Mat. Chem., 2007, 386-397).
• aromatic type polymers have been described more recently in the documents US2005 / 0221135 and US 7037614. These are sulfonated triazine polymers whose monomers are connected by ether bridges (-O-).
• the syntheses described in these documents are complex, expensive and difficult to reproduce. It has further been found that their stability, chemical and dimensional, is insufficient even after a final treatment of crosslinking membranes, which treatment also requires another complex and expensive chemistry.
• This aromatic alkane compound of the invention corresponds to formula (I): - -
• n is in a range from 1 to 20;
• Xi and X 2 which are identical or different, represent S, SO or S0 2 ;
• Ari and Ar 2 which are identical or different, represent a phenylene group at least one of which carries a sulphonic group -SO 3 H or a sulphonate group -SO 3 M, M representing an alkali metal cation.
• the invention also relates to any sulfurized, fluorinated and sulfonated aromatic alkane polymer derived from a monomer according to the invention, that is to say comprising recurring units resulting from the polycondensation of the monomer of the invention with at least one (i.e. one or more) other monomer carrying at least two nucleophilic functions.
• the invention also relates to a method for synthesizing a polymer by poly condensation of at least one aromatic alkane monomer according to the invention, with another monomer carrying at least two nucleophilic functions.
• the invention also relates to the use of an aromatic alkane monomer according to the invention for the manufacture of a polymer membrane that can be used in a PEM type fuel cell.
• the monomer according to the invention From the monomer according to the invention, it has proved indeed possible to synthesize a polymer usable for producing PEM membranes unexpectedly compared to commercial membranes including Nafion ® non-reinforced type, have an ionic conductivity higher. Finally, which is not its least advantage, the polymer resulting from the monomer of the invention can be made compatible with a microporous polymer ePTFE for an optimal reinforcement of the membrane.
• Polymer 2 another example of a polymer according to the invention (Polymer 2), in blocked benzophenone form, as well as a possible synthesis scheme of this polymer by oxidation of the above Polymer 1 (FIG.
• alkane aromatic monomer of the invention sulfur, fluorinated and sulfonated, therefore has the essential characteristic of responding to formula (I):
• n is in a range from 1 to 20;
• Xi and X 2 which are identical or different, represent S, SO or S0 2 ;
• Ari and Ar 2 which are identical or different, represent a phenylene group at least one of which carries a sulphonic group -SO 3 H or a sulphonate group -SO 3 M, M representing an alkali metal cation .
• the fluorinated alkane monomer of the invention of formula (I) has the structural formula:
• R is hydrogen or a substituent for hydrogen.
• the monomer of the invention of formula (I) corresponds to one of the three formulas. , 1-2 and 1-3 respectively shown in Figures 1A, 1B and 1C appended.
• at least one of the phenylene groups carries a sulphonic group -SO 3 H or a sulphonate group -SO 3 M, M representing an alkali metal cation.
• phenylene group carrier it is understood in the present application that the phenylene group itself or one of the possible substituents of its hydrogen atoms is carrying a sulfonic or sulfonate group.
• the monomer of the invention of formula (I) corresponds to one of the three formulas II-1, II-2 and II-3 respectively represented in FIGS. 2A, 2B and 2C appended hereto.
• n preferably ranges from 2 to 20, more preferably from 2 to 8; more particularly still, the alkane monomer of the invention is a butane monomer, that is to say that n is equal to 4. - -
• a preferred characteristic of the monomer of the invention is that at least one of the phenylene groups carries a sulphonate group (-SO 3 M), M representing an alkali metal cation, preferably Na + or K + .
• M representing an alkali metal cation, preferably Na + or K + .
• Xi and X 2 which are identical or different, represent SO or SO 2 , more preferably S0 2 .
• the phenylene groups Ari and Ar 2 may be substituted or unsubstituted by optional substituents other than sulfonic or sulfonated groups on the one hand, other than fluorine on the other hand.
• substituents other than sulfonic or sulfonated groups on the one hand, other than fluorine on the other hand.
• the invention applies in particular to cases where only one phenylene group per monomer of formula (I) is substituted, as in the case where several phenylene groups per monomer are substituted, a single substituent or several substituents, identical or different. different, which may be present on the same phenylene group (s).
• aromatic rings that is to say more exactly hydrogen atoms of these phenylene groups
• substituents aromatic rings include the following substituents: o - Cl; - Br; - CN; - CF 3 ; - N0 2 ; N (CH 3 ) 2 ; even - F;
• substituents are preferably selected from the group consisting of the substituents - CN, - CF 3 , - PO 3 H, - PO 3 M, - F and the mixtures of these substituents.
• the two fluorine atoms confers its polymerizable character on the monomer of the invention, thanks to their electrophilic character well known to those skilled in the art: as a reminder, an electrophilic function or group (atom or group of atoms) (also called Lewis acid or electron acceptor) has a missing pair of electrons and is therefore capable of covalently bonding with a Lewis base; reciprocally, a nucleophilic function or group (atom or group of atoms) (also called Lewis base or donor - - of electrons) has a pair of free electrons and is therefore able to create a covalent bond with a Lewis acid.
• an electrophilic function or group atom or group of atoms
• Lewis acid or electron acceptor also called Lewis acid or electron acceptor
• the alkane aromatic monomer of the invention is an alkali metal salt of 3,3'-bis (4-fluorophenylthio) butane disulfonate, 3,3'-bis (4-fluorophenylsulfoxy) butane disulfonate, or 3,3'-bis (4-fluorophenylthio) butane disulfonate.
• aromatic alkane monomer according to the invention described above is advantageously usable for the synthesis of polymers which may constitute, in sulphonated form, an electrolyte (or membrane, which is equivalent) in a fuel cell.
• polymer is meant any homopolymer or copolymer, especially a block copolymer, comprising at least structural units derived from the monomer of the invention.
• sulfonated monomer or "sulfonated polymer”, by definition in the present application and in known manner, respectively a monomer or polymer bearing one or more sulfonic groups (-SO3H), sulfonates (-SO3M), or mixtures such groups, M representing an alkali metal cation; M is preferably selected from lithium (Li), cesium (Cs), sodium (Na) and potassium (K), more preferably from sodium (Na) and potassium (K). It will be briefly recalled here that it is the sulfonic groups which in a PEM cell ensure the proton conductivity of the polymer used as a membrane.
• FIG. 3 represents an example of a polymer according to the invention, synthesizable from an aromatic alkane monomer according to the invention, as well as a possible synthetic scheme for this polymer from such a monomer.
• Polymer 1 The polymer (hereinafter referred to as "Polymer 1") as represented in FIG. 3, in sulphonated form, consists of two types of structural units connected to each other by ether bridges (-O-).
• This Polymer 1 can be prepared by poly condensation of a monomer according to the invention denoted Al (here, in disulfonated form) with a second monomer (monomer of the triazine type) not according to the invention denoted Bl in FIG. 3, in the presence of a base and an organic solvent, according to a procedure which will be described in detail below.
• Al monomer corresponds to the aromatic alkane monomer of formula ( ⁇ -3) previously described (FIG 2C).
• FIG. 4 represents another example of a polymer (hereinafter referred to as "Polymer 2”) synthesizable from an aromatic alkane monomer according to the invention, as well as a possible synthetic scheme for this polymer 2 by oxidation of the Polymer 1 above, according to a procedure which will be described in detail later.
• Polymer 2 a polymer synthesizable from an aromatic alkane monomer according to the invention
• Polymer 1 is characterized and tested as a proton conducting membrane in a PEM type fuel cell.
• Polymer 1 and Polymer 2 comprise chain ends blocked by hydrophobic and sterically hindered benzophenone blocking groups (denoted by B in FIGS. 3 and 4) intended to reduce the solubility of the polymer in water.
• the monomer Al is 3,3 'bis (4-fluorophenylsulphonyl) butane disulfonated, whose formula (reproduced for example in Figure 3, M being here sodium Na) is as follows:
• This Al monomer (or Compound 3 in Figure 5) was prepared according to the procedure shown diagrammatically in Figure 5, in three successive steps, as detailed below.
• the solution is then cooled with an ice bath (temperature between 0 ° C. and 5 ° C.), still under a stream of nitrogen, and 1,4-diiodobutane (25.0) is added dropwise. 0.81 mmol).
• the temperature is allowed to rise to room temperature (25 ° C) and then heated overnight (about 12 hours) at 40 ° C.
• the next day the temperature is raised to 60 ° C for one hour, then the solution is poured into a 3.0 liter beaker and 2.5 liters of deionized water are added.
• the white precipitate thus obtained is stirred at ambient temperature (23 ° C.) for 30 minutes; it is then isolated by filtration on filter paper.
• a one-liter, one-liter round flask equipped with a condenser, magnetic bar, and nitrogen inlet is charged with 20.4 g (65.7 mmol) of Compound 1 and 500 ml of glacial acetic acid. After stirring for 5 minutes at room temperature (23 ° C.), the suspension is cooled by an ice bath (between 0 ° and 5 ° C.) and 61.27 g (388 mmol) of KMnO 4 are then added ; after stirring for 15 minutes, 35 ml of concentrated (98%) sulfuric acid are added dropwise.
• reaction mixture After stirring for 30 minutes at 0 ° C to 5 ° C, the reaction mixture is stirred overnight (about 12 hours) at room temperature (23 ° C). The reaction mixture is poured into a 3.0 liter beaker and 1.5 liters of deionized water are added. The mixture is stirred for 15 minutes at room temperature (23 ° C.) and then cooled with an ice bath (0 to 5 ° C.). With stirring, NaOH (solid) is gradually added until a pH of 7 is reached. To the half of the reaction mixture previously prepared, 1 liter of dichloromethane is added and, after stirring for 30 min, the organic phase is separated. of the aqueous phase in a separatory funnel.
• a solid part (hydrolysed Mn0 2 ) is separated from the organic phase by filtering through a microporous silica ("HyFlo Super Elemental Cylinder" Sigma-Aldrich).
• the organic phase is dried over anhydrous Na 2 SO 4 , filtered and the dichloromethane is removed on a rotary evaporator at 40 ° C.
• the crude solid product (22.8 g) thus obtained is dissolved in acetone (in 3 parts of 8.0 g of product for 1.250 liters of acetone) and refluxed with activated charcoal for one hour.
• the activated carbon is removed by filtration on filter paper and the filtrate is cooled to room temperature until the product is recrystallized.
• the white crystals obtained are isolated by filtration and dried in the oven (60 ° C., 1 mbar) overnight (about 12 hours).
• Compound 3 or monomer Al (3,3'-bis (4-fluorophenylsulphonyl) butane disulfonated) is prepared according to the following procedure and diagrammatically in FIG. 5C.
• Compound 2 (8.0 g, 21.36 mmol) is placed in a 250 ml three-neck flask equipped with a condenser and a magnetic bar coated with glass. The apparatus is purged with nitrogen and left under an inert atmosphere. 20 ml H 2 SO 4 (98%) and then 20 ml (37.3 g) of oleum containing 65% of SO 3 are added . The reaction medium is heated at 120 ° C. for 4 hours under a gentle stream of nitrogen. Once the sulfonation is complete, the reaction mixture is cooled to 90 ° C and then poured still hot into 250 g of ice.
• the monomer B1 for a booster not according to the present invention, is 2,4 - [(4-hydroxyphenylsulfanyl phenyl)] - 6- (phenyl) - [l, 3,5] -triazine, whose formula ( already reproduced in Figure 3) is as follows:
• This B1 monomer (or Compound 5 in Fig. 7) was prepared according to the procedure shown schematically in Fig. 7, in two successive steps, as detailed below.
• Compound 4 or 2,4-bis- (p -fluorophenyl) -6-phenyl- [l, 3,5] -triazine is prepared, according to the procedure which follows and schematized in FIG. 7A.
• the flask is immersed in an oil bath heated to 158 ° C and left overnight (about 12 hours) at 150 ° C (temperature inside the reaction flask), a slight stream of nitrogen being above the reaction mixture.
• the reaction product is then cooled to room temperature (23 ° C.) and hydrolysed by adding 300 g of ice and 60 g of 36% HCl.
• the solid is filtered, then dispersed in water and washed until a neutral pH is obtained.
• the white solid is stirred in 500 ml of methanol, refluxed for 30 minutes and then allowed to cool to room temperature (23 ° C.). Finally, the product is filtered and dried at 60 ° C. under vacuum.
• the purification of the product can not be done in a single step: about 250 ml of aliquot of the reaction are collected and poured into an extraction bulb (3 liters) containing 2.6 liters of ethyl acetate / water (ratio 1/1). The rest of the product is kept under a constant stream of nitrogen. The mixture placed in the extraction funnel is shaken (the color changes from orange to lemon yellow) and the desired product is extracted into the ethyl acetate phase (the DMSO / H 2 O phase contains only traces of the desired product ). The organic phase is washed with 100 ml of NaHCO 3 solution, followed by washing with 100 ml of H 2 O; the organic phase is then dried with anhydrous MgSO 4 .
• the process is repeated twice with the other two remaining 250 ml aliquots of the reaction mixture.
• the ethyl acetate phase is evaporated using the rotary evaporator, there remains a viscous slightly orange liquid having the appearance of honey (containing a small amount of DMSO).
• DMSO residues are removed at 100 ° C under reduced pressure.
• a small amount of acetone (10 ml) is added followed by 40 ml of diethyl ether.
• the solid becomes immediately creamy white, it is filtered on a ceramic filter.
• the residual thiol is removed from the reaction product by column chromatography using hexane / CH 2 Cl 2 / ethyl acetate / methanol (4/2/1/1 weight ratios) as the mobile phase.
• the molecular weight of the product as measured by "Matrix-assisted Laser Desorption / Ionization" mass spectrometry (positive mode, dithranol matrix) is equal to 558.1 (calculated theoretical value equal to 557.7).
• Monomer B1 is dried at 60 ° C under vacuum overnight.
• Al monomer and base (Na 2 CO 3) are dried separately at 150 ° C under vacuum overnight. Then the three compounds are mixed and dried at 160 ° C under vacuum for one hour.
• the copolymerization of the monomers A1 and B1 is carried out in a 100 ml three-neck round-bottomed flask. The flask is equipped with a nitrogen inlet, a thermometer, a magnetic stirrer and a "Dean Stark" separator surmounted by a coolant.
• the glass parts of the apparatus are dried under vacuum using a hot air gun to reach a temperature of at least 100 ° C in the reaction flask.
• the reaction flask is loaded with the monomer Al (1.76 g, 3.04 mmol), the monomer B1 (1.7 g, 3.04 mmol), the anhydrous sodium carbonate (0.97 g, ie 9 g, 13 mmol), anhydrous N, N-dimethylacetamide (20 ml) and 4 ml of organic solvent (toluene) as an azeotropic agent.
• the reaction flask is heated at 100 ° C in an oil bath for 90 min (azeotropic distillation).
• the toluene circulation valve is then closed and the toluene is distilled at 110 ° C for 90 minutes.
• the temperature of the oil bath is then increased by 10 degrees every 30 minutes, up to 148 ° C.
• the toluene is removed from the apparatus ("Dean Stark") by the hatch, then the temperature of the oil bath is increased to about 160 ° C and maintained at this value all night (20 hours in total). Then the temperature dropped to about 90 ° C inside the flask, removing the flask from the oil bath. 8 mg of 4-fluorobenzophenone dissolved in 5 ml of anhydrous ⁇ , ⁇ -dimethylacetamide are then added to the reaction using a syringe. The flask is returned to the oil bath at 160 ° C for an additional 1 hour. The reaction mixture is then allowed to cool to room temperature (23 ° C); then the polymer is poured dropwise into 500 ml of 2-propanol with stirring.
• the fibrous precipitate is recovered by filtration and washed with 2-propanol and then dried in an oven (80 ° C., 1 mbar) overnight (12 hours). 4.1 g of solid material are thus obtained.
• the polymer is washed with 100 ml of distilled water for 30 minutes. The pH is adjusted to about 4 with 10% aqueous HCI.
• the product is isolated by filtration, washed with distilled water and dried in an oven overnight (12 hours at 80 ° C., under 1 mbar).
• Polymer 1 (1.0 g) is placed in a 50 ml two-neck flask equipped with a condenser, then 12 ml of glacial acetic acid are added and the dispersion obtained is stirred at room temperature (23 ° C.) for 30 minutes. min. 500 ⁇ l of concentrated H 2 SO 4 are then added and, after stirring for 3 minutes, 2 ml of H 2 0 2 (50% aqueous solution). The dispersion is then stirred at room temperature overnight (12 hours). Platinum (2 cm 2 plate) is placed in the flask for destruction of the oxygen peroxide, and the reaction mixture is then stirred for 2 hours at room temperature. The acetic acid is evaporated in an oil bath of 50 ° C and in a strong stream of nitrogen.
• the solid (pale yellow color) obtained is then washed with successive portions of 25 ml of distilled water until a pH of 6 is obtained.
• the gelatinous solid is isolated by filtration and dried overnight at room temperature. oven (80 ° C, under 1 mbar).
• FIG. 9 reproduces the 1 H NMR spectrum (360 MHz ) Polymer 2 thus obtained, dissolved in DMSO- ⁇ 3 ⁇ 4.
• the polymer (650 mg) previously dissolved in 10 ml of ⁇ , ⁇ -dimethylacetamide is filtered in two stages, firstly through a microfilter (company "Millipore") made of PTFE (polytetrafluoroethylene) having a pore size of 5. , 0 ⁇ , then through a second microfilter of about 0.45 ⁇ . Then the polymer solution thus filtered is poured into a mold consisting of two superimposed glass plates, the upper plate having a recess (dimensions 9 cm ⁇ 9 cm) of depth equal to 1 mm; it is then heated at 50 ° C for 12 h, then 12 h at 60 ° C. Then traces of organic solvent are removed from the membrane thus formed by immersing the latter in a distilled water bath for about 4 hours.
• Polymer 1 For the acidification of the membrane (as a reminder, exchange of the cation M + by H + ), Polymer 1 is initially immersed in 200 ml of H 2 SO 4 (aqueous, 3.8M) for 2 h. Double-distilled H 2 SO 4 (Sigma Aldrich) is used to avoid traces of metals. Distilled water is then added in several stages (total time about 12 hours) to reach a pH close to 7; the membrane is then stored in distilled water overnight (about 12 hours).
• H 2 SO 4 aqueous, 3.8M
• Double-distilled H 2 SO 4 Sigma Aldrich
• Distilled water is then added in several stages (total time about 12 hours) to reach a pH close to 7; the membrane is then stored in distilled water overnight (about 12 hours).
• the proton conductivity of the membrane expressed in S / cm (Siemens per centimeter) is determined as indicated below.
• Disc-shaped membranes 2 cm in diameter (thickness 60 to 65 ⁇ ) are cut using a punch.
• the proton conductivity of the membrane is determined by the measurement of the real part (Ohmic) and the imaginary part (Capacitance) of the complex impedance, in the frequency range between 100 kHz and 10 Hz (with amplitude of 100 mV AC). Measurements are made with an impedance / AC potentiostat (Zahner, Germany).
• Nyquist plots are generated by the measurements of a successive stack of one, two, three and up to six membranes (totally moistened) sandwiched between two platinum electrodes of the same circular shape as the membranes.
• the value intercepting the real axis of Nyquist graph is reported, that is to say a value of the imaginary component of the impedance at zero.
• these points are aligned on an affine line whose slope directly determines the value of the resistance of the membrane. Its ordinate at the origin determines the contact resistance between the membranes and the platinum electrodes.
• the membranes derived from Polymer 1 showed remarkable proton conductivity values, equal to about 95 mS / cm at 25 ° C, higher than the conductivity value (about 70 mS / cm) measured on the commercial membrane (" Nafion ® 112 "), unreinforced, of the same thickness and rigorously tested under the same conditions.
• This second monomer not in accordance with the invention was certainly also a sulfur-type monomer, fluorinated and sulfonated, therefore structurally close to the monomer according to the invention, but not alkane type unlike the latter.
• SFPS 3,3'-disulfo-4,4'-diflurorophenylsulfone
• Membranes were then prepared from this polymer not according to the invention, as described in paragraph V-5 above. They have been found to be relatively brittle, with high rigidity, and significantly reduced mechanical endurance compared to membranes prepared from the alkane monomer according to the invention.
• the monomers of the invention make it possible to manufacture PEM polymers and membranes which, unexpectedly, have, on the one hand, an ionic conductivity which may be greater than those of commercial membranes of the Nafion® non-reinforced type, and of on the other hand a mechanical endurance which can be improved over that available with other polymers known for this type of application, poly (arylene ether sulphone) type.

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