Abstract: The invention pertains to a process for stabilizing a semi-crystalline fluoropolymer comprising ion exchange groups, said process comprising: suspending at least one semi-crystalline fluoropolymer having ion exchange groups [polymer (I)] in at least one fluorinated organic dispersing medium [medium (M)] so as to obtain a dispersion (D) of polymer (I) in a dispersing medium (M), contacting said dispersion (D) with fluorine under irradiation with U.V. radiation so as to obtain a stabilized polymer. Still objects of the invention arc a stable semi-crystalline fluoropolymer as above defined having a low amount of unstable ends groups of —COF type, the use of the stabilized fluoropolymer obtained by the process or of the stable fluoropolymer in fuel cells devices, a membrane and a membrane-electrode assembly comprising said fluoropolymers.

Abstract: Fine fluoropolymer powders substantially fluorinated surfactant free, in particular fluorinated ionic surfactants, preferably perfluorooctanoic acid or its salts, comprising an anionic polyelectrolyte.

Abstract: A process for preparing a fluoropolymer dispersion that is substantially anionic fluorinated surfactant free includes adding to a fluoropolymer dispersion a nonionic surfactant having a cloud point (CP) between 40 and 80° C. in a concentration of 1.5% to 50% by weight of the fluoropolymer, heating the dispersion up to a temperature Tc in a range of CP±10°C., decanting the dispersion in a reactor at Tc until obtaining a lower aqueous phase containing a concentrated fluoropolymer dispersion and an upper aqueous phase substantially not containing the fluoropolymer dispersion, washing the decanted dispersion with a solution of water and nonionic surfactant having a concentration of the nonionic surfactant of 0.5% to 50% by weight of the fluoropolymer, removing the upper aqueous phase from the upper part of the reactor, and discharge and recovery of the fluoropolymer dispersion.

Abstract: Polymers of formula Q-O-[A-B]z-[A-B?]z-A-Q???(I) wherein: A=-(X)a—O-A?-(X?)b— with A?=perfluoropolyether chain and X, X?=—CF2—, —CF2CF2—; a, b=0.1 with the proviso that a=1 if A is linked to Q-O—; b=0 when A is linked to Q?; B derives from homopolymerizable olefins by radical route, of formula: —[(CR1R2—CR3R4)j(CR5R6—CR7R8)j?]—??(Ia) wherein j is an integer from 1 to 30, j? is an integer from 0 to 29 with the proviso that (j+j?) is higher than 2 and lower than 30; R1-R8 are halogen; H; C1-C6 (per)haloalkyl; C1-C6 alkyl; or C1-C6 oxy(per)fluoroalkyl; B?=B but at least one among R1-R8 has a meaning different from that in B; z, z? are such that the number average molecular weight of the polymer of formula (I) is between 500 and 150,000; Q, Q?=C1-C3 (per)fluoroalkyl or functional end group —(CFW)-Dq-Tk; W=F, CF3; k and q are integers, k ranges from 1 to 4, q is an integer and is equal to 0 or 1; with the proviso that at least one of Q, Q? is functional end group.

Abstract: A (per)fluoroelastomeric composition curable by peroxidic way comprising for 100 phr of (per)fluoroelastomer: as filler, from 2 to 70 phr of carbon black having a surface area between 25 and 35 m2/g; as crosslinking agent, from 0.5 to 10 phr of a bis-olefin having general formula: wherein: R1, R2, R3, R4, R5, R6, equal to or different from each other, are H or C1-C5 alkyls; Z is selected between a linear or branched C1-C18 alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.

Abstract: A process to substantially remove fluorinated anionic surfactants from fluoropolymer dispersions comprising the following steps: a) addition to the fluoropolymer dispersion of one or more non fluorinated surfactants; b) contact of the dispersion with an anionic exchanger; c) separation of the dispersion from the anionic exchanger and recovery of the dispersion substantially fluorinated anionic surfactant free.

Abstract: Aqueous dispersions comprising a mixture of: A) from 0.05% by weight to 10% by weight of salts of perfluoropolyether di-carboxylic derivatives having formula: T-O—Rf-T??(IA) wherein T=—CF2—COOZ or —CF2CF2—COOZ wherein Z=Na, K, NH4, R1(R2)(R3)N wherein R1=R2=alkyl or hydroxyalkyl, R3=H, alkyl or hydroxyalkyl, Rf is a (per)fluoropolyoxyalkylene chain having number average molecular weight between 500 and 10,000. B) from 0.01% to 5% by weight of water-dispersible or water-soluble cationic polymers, having a charge density, defined as number of equivalents per weight unit of dry polymer, higher than 1 meq/g of dry polymer.

Abstract: The invention pertains to a process for operating a polymer electrolyte membrane fuel cell (PEMFC), said PEMFC comprising: (a) a membrane comprising at least one fluorinated ionomer [polymer (I)] comprising recurring units derived from tetrafluoroethylene (TFE) and from at least one monomer of formula (M): wherein m is an integer between 1 and 6 and X? is chosen among halogens (Cl, F, Br, I), —O?M+, wherein M+ is a cation selected among H+, NH4+, K+, Li+, Na+, or mixtures thereof, said polymer (I) having an equivalent weight (EW) of from 700 to 850 g/eq.; (b) a cathode; (c) an anode; said process comprising: (i) feeding gaseous reactants at the electrodes at a relative humidity of at most 66%; (ii) maintaining an average current density between 0.05 and 1.5 A/cm2; and (iii) maintaining an average temperature of more than 65° C.

Abstract: Compounds having the following formula: wherein: A and A1, equal or different, are respectively H or an aromatic end group as defined below; optionally said aromatic group being substituted; n is an integer different from zero, such that the number average molecular weight of the compound of formula (I) is in the range 1,800-50,000, T is the bivalent group —Y—CH2—CFW1—O—Rf—CFW2—CH2—Y— wherein: Y=O, S; W1 and W2, equal or different, are F, CF3; Rf is a (per) fluoropolyoxyalkylene chain formed of one or more repeating units, statistically distributed along the chain; R1, R2, R3, equal to or different from each other, are selected from H; linear or branched C1-C8 perfluoroalkyl, linear or branched C1-C15 (per) fluorooxyalkyl; linear or branched C1-C8 alkyl; linear or branched C1-C8a oxyalkyl, optionally containing one or more oxygen atoms; NO2; CN.

Abstract: Polyurethanes-urea based on perfluoropolyethers comprising ionizable groups and pendant groups having the following structure: —RI—Si(ORII)n(OH)3?n??(I) wherein: RI is alkylene from 1 to 10 carbon atoms; RII is an alkyl group from 1 to 4 carbon atoms; n is an integer from 0 to 3.

Abstract: A process for producing a polymer by polymerizing at least one fluorinated monomer in the presence of a radical initiator and a surfactant in a polymerization medium containing essentially only carbon dioxide. The surfactant is a functional (per)fluoropolyether having recurring units (R1) and at least one functional group containing a heteroatom other than fluorine, the recurring units containing at least one ether linkage in the main chain and at least one fluorine atom. Molded article containing the polymer obtained from the process.

Abstract: Use for the preparation of paints for substrata coatings of aqueous dispersions of VDF-based polymers having an average particle size between 0.260 and 0.3 micrometers comprising a bifunctional surfactant of formula: A-Rf-B ??(I) wherein A=—O—CFX—COOM; B=—CFX—COOM with X=F, CF3; M=NH4, alkaline metal, H; Rf is a linear or branched perfluoroalkyl chain, or a (per)fluoropolyether chain such that the number average molecular weight of (I) is in the range 600-800.

Abstract: Polymeric compositions comprising: 1) at least one thermoprocessable semicrystalline halo-polymer; 2) an additive in amounts between 0.01 and 10% by weight of 1) one or more (per)fluoropolyether polymers of formula: Q-O-[A-B]z-[A-B?]z?-A-Q? (I) wherein: A=—(X)a—O-A?-(X?)b— wherein A? is a perfluoropolyether chain; X, X?=—CF2—, —CF2CF2—, —CF(CF3)—; a, b=0 or 1; B derives from one or more olefins, of which at least one homopolymerizable by radical way, of formula: —[(CR1R2—CR3R4)j(CR5R6—CR7R8)j?]— (Ia) wherein j=1-30, j?=0-29, with the proviso that 2<(j+j?)<30; R1-R8=halogen, H, C1-C6 (per)haloalkyl, C1-C6 alkyl, or C1-C6 oxy(per)fluoroalkyl; B?=(Ia) but at least one of R1-R8 has a meaning different from that in B, and 2?(j+j?)<30; z?2; z? is 0 or an integer; z, z? are such that the number average molecular weight of (I) is between 500 and 500,000; Q, Q?=C1-C3 perfluoroalkyl; C1-C6 alkyl; or functional end group(s).

Abstract: Peroxidic perfluoropolyethers having formula: X1—O(CF2O)n1(CF2CF2O)m1(CF2(CF2)zCF2O)p1(O)h—X2??(I) wherein: X1 and X2, equal to or different from each other, are chain end groups selected among —CF2COF, —COF, —SO2F; n1, m1, p1 and h are integers such that the number average molecular weight is in the range 700-100,000; z=1 or 2; with the proviso that: the m1/n1 ratio is between 0.2 and 10; the p1/(n1+m1) ratio is lower than 0.05; the h/(n1+m1+p1) ratio is such that the PO content, defined as grams of active oxygen/100 g of compound, is in the range 0.8-4.5, preferably 1.4-3.8; the perfluorooxyalkylene units being statistically distributed along the polymeric chain.

Abstract: A process for obtaining vinyl compounds by dehalogenation of halofluorinated compounds having a linear, branched or cyclic structure, said halofluorinated compounds containing in the molecule at least one group: wherein Y1 and Y2, equal to or different from each other, are selected from Cl, Br, I; wherein the halofluorinated compounds are dehalogenated in the presence of a transition metal, or of transition metal couples, by operating in a biphasic system of solvents immiscible among each other, formed of a (per)fluorinated solvent and a dipolar aprotic or protic solvent (co-solvent), wherein the ratio moles co-solvent/equivalents of the halofluorinated compound ranges from 0.5 to 10, preferably from 0.5 to 5, still more preferably from 1 to 3.

Abstract: A (per)fluoroelastomeric composition curable by peroxidic way comprising: 100 phr as (per)fluoroelastomer as filler, 0.5-50 phr of silica having a pH value, determined according to the DIN ISO 787-9 standard, higher than 7, preferably higher than 8, as crosslinking agent, from 0.5 to 10 phr of a bis-olefin having general formula: wherein: R1, R2, R3, R4, R5, R6, equal to or different from each other, are H or C1-C5 alkyls; Z is selected between a C1-C18 linear or branched alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.

Abstract: The invention pertain to a process for purifying a fluoropolymer dispersion, said process comprising: (i) providing an aqueous dispersion (D) of at least one fluoropolymer [polymer (F)] comprising at least one fluorinated surfactant [surfactant (FS)], having a solids content (SC) of 15% by weight or more; (ii) adding to said aqueous dispersion (D) at least one non-ionic non-fluorinated surfactant [surfactant (NS)]; (iii) adjusting said solid content (SC) to less than 10% by weight, to obtain a diluted aqueous dispersion (dD); (iv) contacting said diluted aqueous dispersion (dD) with at least one adsorbing material, so as to obtain an aqueous dispersion of polymer (F) having a content of the fluorinated surfactant (FS) of less than 1 ppm based on the total weight of solids. Still an object of the invention is an aqueous fluoropolymer dispersion comprising less than 1 ppm of fluorinated surfactant.

Abstract: Fluoroelastomers, curable by peroxidic route, obtainable by polymerizing the following monomers: a) C2-C8 hydrogenated fluoroolefins; b) fluorovinylethers of general formula: CFX?CXOCF2OR ??(I) c) bis-olefins having general formula: RI1RI2 C?CRI3-Z-CRI4?CRI5RI6??(IA) and optionally: d) one or more fluorinated olefinic comonomers selected from perfluoroalkylvinylethers (PAVE) CF2?CFOR2f, perfluorooxyalkylvinylethers CF2?CFOXa, e) C2-C8 perfluorolefins; f) one or more C2-C8 non fluorinated olefinic comonomers said fluoroelastomers comprising iodine and/or bromine atoms in the chain and/or in end position.

Abstract: A process for preparing fluorovinylethers having general formula: RfO—CF?CF2??(IA) wherein Rf is a fluorinated or perfluorinated alkyl or cycloalkyl substituent; comprising the following reaction steps: 1) reaction of a hypofluorite; 2) dehalogenation or dehydrohalogenation of the fluorohalogenethers obtained in step 1) and obtainment of vinyl ethers; 3) fluorination with fluorine of the vinyl ethers and obtainment of fluorohalogenethers; and 4) dehydrohalogenation of the fluorohalogenethers and obtainment of the fluorovinylethers of formula (IV). The compounds of formula (IA) can be used, for example, in the preparation of various polymers, such as fluorinated elastomers and fluorinated thermoprocessable semicrystalline polymers.

Abstract: Liquid formulations of imidoalkanepercarboxylic acids, in the form of aqueous dispersions comprising, in percentages by weight relative to the total weight of the composition: A) from ?7% to 40% and preferably from 10% to 20% of imidoalka-nepercarhoxylic acids having the general formula (I), the said imidoalkanepercarboxylic acids being in the ? form and having a dissolution time, determined via the test of the rate of dissolution at a temperature of 40° C. or 18° C., of not more than 5 minutes when determined at 40° C. or 15 minutes when determined at 18° C., for an amount of dissolved acid equal to 99% of the theoretical amount; B) from 0.001% to 0.9% of a nonionic surfactant; the said dispersions having a viscosity of not more than 2000 mPa·sec at 25° C. by applying a shear rate of 20 s?1; in which the dissolution time of the component A), determined via the test of the rate of dissolution at a temperature of 40° C. or 18° C., is not more than 5 minutes when determined at 40° C.