초록 ▼

Ionomeric membranes comprising (per)fluorinated, se-micrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, which used in fuel cells, under the following conditions: membrane thickness 50 μm assembled between two electrodes catalyzed with 0.

Ionomeric membranes comprising (per)fluorinated, se-micrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, which used in fuel cells, under the following conditions: membrane thickness 50 μm assembled between two electrodes catalyzed with 0.6 mg/cm2 Pt/C and treated with 0.7 mg/cm2 of Nafion��, having a 10 cm2 area; hydrogen and air feeding, both at the pressure of 0.25 MPa, both saturated with water at 80�� C.; cell temperature 75�� C.; for membranes formed of copolymers TFE/F2C═CF--O--(CF2)2--SO2F, give the following maximum specific power (PMAX) values, at the indicated EW values: at EW=670 PMAX higher than 0.55 Watt/cm2; at EW=830 PMAX higher than 0.66 Watt/cm2; at EW=1,160 PMAX higher than 0.50 Watt/cm2; at EW=1,600 PMAX higher than 0.32 Watt/cm2.

대표청구항 ▼

The invention claimed is: 1. A method of using a membrane in fuel cell applications, comprising the step of providing an ionomeric membrane made of (per)fluorinated, semicrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, when used in a fuel cell

The invention claimed is: 1. A method of using a membrane in fuel cell applications, comprising the step of providing an ionomeric membrane made of (per)fluorinated, semicrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, when used in a fuel cell under the following conditions: 50 μm membrane thickness assembled between two electrodes catalyzed with 0.6 mg/cm2 Pt supported on Carbon (Pt/C) and treated with 0.7 mg/cm2 of perfluorinated polymer, having 10cm2 area; hydrogen and air feeding, both at the pressure of 0.25 MPa, both saturated with water at 80�� C.; cell temperature 75�� C.; and is formed of copolymers of TFE/F2C═CF--O--(CF2)2--SO2F, gives the following maximum specific power values (PMAX), at the indicated EW values: EW = 670 PMAX higher than 0.55 Watt/cm2; EW = 830 PMAX higher than 0.66 Watt/cm2; EW = 1,160 PMAX higher than 0.50 Watt/cm2; EW = 1,600 PMAX higher than 0.32 Watt/cm2. 2. The method of claim 1, wherein the ionomeric membrane comprises (per)fluorinated ionomers comprising: (A) monomeric units deriving from one or more fluorinated monomers containing at least one ethylene unsaturation; and (B) fluorinated monomeric units containing suiphonyl groups--SO2F in amount to give an equivalent weight in the indicated range. 3. The method of claim 2, wherein the fluorinated monomers of type (A) are selected from: vinylidene fluoride (VDF); C2-C8 perfluoroolefins; C2-C08 chloro-and/or bromo-and/or iodo-fluoroolefins; CF2═CFORf1 (per)fluoroalkylvinylethers (PAVE), wherein Rf1 is a C1-C6 (per)fluoroalkyl; CF2=CFOX perfluoro-oxyalkylvinylethers, wherein X is a C1-C12 perfluoro-oxyalkyl having one or more ether groups. 4. The method of claim 3, containing sulphonic perfluorinate ionomers comprising: monomeric units deriving from TFE; monomeric units deriving from CF2═CF--O--CF2CF2SO2F. 5. The method of claim 2, wherein the fluorinated monomers of type (B) are selected from one or more of the following: F2C═CF--O--CF2--CF2--SO2 F; F2C═CF--O--[CF2--CXAF--O] nA--(CF2)nB--SO2F wherein XA=C1, F or CF3; nA=1-10, nB=2, 3; F2C═CF--O--CF2CF2--CF2 --SO2F; F2C═CF--Ar--SO2F wherein Ar is an aryl ring. 6. The method of claim 2, wherein alternatively the fluorinated monomers (B) are selected from the following: F2C═CF--O--CF2--CF2--Y; F2C═CF--O--[CF2-CXAF--O]nA --(CF2)nB--Y F2C═CF--O--CF2--CF2--CF2 --Y F2C═CF--Ar--Y; wherein XA=C1, F or CF3; nA=1-10, nB=2, 3; Ar is an aryl ring; Y is a precursor group of the carboxylic group, selected from the following: CN, COF,COON, COORB, COOM, CONR2BR3B, wherein RB is C1-C10, and R2B and R3B, equal or different, are H or have the RB meaning; optionally said fluorinated monomers (B) with end group Y being in admixture with fluorinated monomers containing sulphonyl groups--SO2F, the total amount of monomers (B) being such to give the equivalent weight as above indicated. 7. The method of claim 1, wherein the sulphonic fluorinated jonomers contain from 0.01% to 2% by moles of monomeric units deriving from a bis-olefin of formula: description="In-line Formulae" end="lead"R1R2C═CH--(CF2)m--CH═CR5R6 (I)description="In-line Formulae" end="tail" wherein: m=2-10; R1, R2, R5, R6, equal to or different from each other, are H or C01-C05 alkyl groups. 8. The method of claim 1, wherein the amorphous (per)fluorinated ionomers are in admixture with crosslinking agents and then crosslinked. 9. The method of claim 8, wherein the ionomer comprises monomeric units deriving from TFE; monomeric units deriving from CF2═CF--O--CF2CF2SO2F; monomeric units deriving from the bis-olefin of formula (I); iodine atoms in terminal position. 10. The method of claim 8, wherein to the ionomer mixture with the crosslinking agents the following components are optionally added: a crosslinking co-agent, in an amount between 0.5 and 100% by weight with respect to the polymer; a metal compound, in amounts between to 1% and 15% by weight with respect to the polymer, said metal compound selected from divalent metal oxides or hydroxides optionally combined with a weak acid salt; thickening additives, pigments, antioxidants, stabilizers; inorganic or polymeric reinforcing fillers; said fillers having a particle size from 10 to 100 nm. 11. The method of claim 10, wherein said metal compound comprises at least one of Mg, Zn, Ca and Pb. 12. The method of claim 10, wherein said weak acid salt are selected from the group consisting of: Ba, Na, K. Pb, and Ca stearates, benzoates, carbonates, oxalates or phosphites. 13. The method of claim 10, wherein said filler comprises fibrillable PTFE. 14. The method of claim 8, wherein the ionomer is mixed with fluoroelastomers that are co-curable with the ionomer. 15. The method of claim 14, wherein the fluoroelastomers comprise iodine and/or bromine atoms. 16. The method of claim 1, wherein the ionomer is mixed with a fluoropolymer selected from the following: crystalline fluoropolymers, optionally modified with a comonomer selected from HFP (hexafluoropropene), VE (vinylethers). 17. The method of claim 1, wherein the membranes, before the conversion of the functional precursor groups to the acid groups, are reinforced by adhering by hot lamination to a reinforcement net. 18. The method of claim 17, wherein the membranes are reinforced with TFE nets. 19. The method of claim 1, comprising ionomers having MFI values measured at 280�� C. and 10 Kg (ASTM D 1238-52T), equal to or lower than 0.6 g/10 mm. 20. The method of claim 1, wherein the electrodes have 10 cm2 area and are formed of a carbon cloth having a thickness of 350 μm and weight for surface unit of 116 g/cm2, said carbon cloth being treated on one side as described hereinafter: a first treatment is carried out with a PTFE/carbon mixture so as to make the sheet surface hydrophobic; subsequently, one side of the surface is catalyzed with Pt supported on carbon powder having a surface area of 250 m2/g, the Pt concentration being 30% by weight with respect to the carbon powder and the Pt surface concentration being 0.6 mg/cm2; the catalyzed side is treated with the ionomeric polymer having equivalent weight 1,100 eq/g and having the following structure: a'and b'being such to give the required equivalent weight; so as to have a surface concentration of said polymer of 0.7 g/cm2. 21. The method of claim 1, wherein the polymers have an EW of from 450 to 1,650 g/eq. 22. A method of using a membrane in electrolyzers for HCI, comprising the step of providing an ionomeric membrane made of (per) fluorinated, semicrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, when used in a fuel cell under the following conditions: 50 μm membrane thickness assembled between two electrodes catalyzed with 0.6 mg/cm2 Pt supported on Carbon (Pt/C) and treated with 0.7 mg/cm2 of perfluorinated polymer, having 10 cm2 area; hydrogen and air feeding, both at the pressure of 0.25 MPa, both saturated with water at 80�� C.; cell temperature 75�� C.; and is formed of copolymers of TFE/F2C═CF--O--(CF2)2--SO2F, gives the following maximum specific power values (PMAX), at the indicated EW values: EW = 670 PMAX higher than 0.55 Watt/cm2; EW = 830 PMAX higher than 0.66 Watt/cm2; EW = 1,160 PMAX higher than 0.50 Watt/cm2; EW = 1,600 PMAX higher than 0.32 Watt/cm2. 23. A method of using a membrane in electrolyzers for a chloro/soda process, comprising the step of providing an ionomeric membrane made of (per)fluorinated, semicrystalline or amorphous, ionomeric polymers, having equivalent weight (EW) from 380 g/eq to 1,800 g/eq, when used in a fuel cell under the following conditions: 50 μm membrane thickness assembled between two electrodes catalyzed with 0.6 mg/cm2 Pt supported on Carbon (Pt/C) and treated with 0.7 mg/cm2 of perfluorinated polymer, having 10cm2 area; hydrogen and air feeding, both at the pressure of 0.25 MPa, both saturated with water at 80�� C.; cell temperature 75�� C.; and is formed of copolymers of TFE/F2C═CF--O--(CF2)2--SO2F, gives the following maximum specific power values (PMAX), at the indicated EW values: EW = 670 PMAX higher than 0.55 Watt/cm2; EW = 830 PMAX higher than 0.66 Watt/cm2; EW = 1,160 PMAX higher than 0.50 Watt/cm2; EW = 1,600 PMAX higher than 0.32 Watt/cm2.