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

Abstract: The invention pertains to a polymerization process including polymerizing at least one fluorinated monomer in the presence of a radical initiator and a surfactant in a polymerization medium containing carbon dioxide to provide a polymer product, characterized in that the surfactant is a functional (per)fluoropolyether, which is a polymer comprising recurring units (R1) and at least one functional group having a heteroatom other than fluorine, said recurring units having at least one ether linkage in the main chain and at least one fluorine atom (fluoropolyoxyalkene chain).

Abstract: A process for preparing fluoropolymer dispersions, substantially anionic fluorinated surfactant free, comprising: step a1) to a fluoropolymer dispersion it is added: a nonionic surfactant having cloud point (CP) between 40°and 80° C., in an amount from 1.5% to 50% by weight, with respect to the fluoropolymer of the dispersion; step a2) heating of the dispersion up to a temperature Tc comprised in the range CP±10° C.; step a2?) decantation in a reactor at the temperature Tc, until obtaining: a lower aqueous phase formed of the concentrated fluoropolymer dispersion, an upper aqueous phase substantially not containing fluoropolymer; step a3) washing of the decanted dispersion obtained in a2?) with a solution of water and nonionic surfactant, wherein the concentration by weight of the surfactant in the solution is from 0.

Abstract: A process to substantially remove the fluorinated anionic surfactants comprising the following steps: a) addition to a fluoropolymer dispersion of a nonionic surfactant, in an amount in the range 1.5%–25% by weight, referred to the fluoropolymer weight; b) addition to the dispersion of a salt, soluble in water and not giving precipitates in the dispersion under the use conditions; c) contact of the dispersion with a basic anionic exchanger; d) separation of the dispersion from the basic anionic exchanger; before step d) the dispersion being filterable on a 180 micrometer net and successively on a 10 micrometer net.

Abstract: A process to substantially remove the fluorinated anionic surfactants from fluoropolymer dispersions comprising the following steps: a) addition to the fluoropolymer dispersion of an anionic polyelectrolyte; 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: 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: A process to substantially remove the fluorinated anionic surfactants comprising the following steps: a) addition to a fluoropolymer dispersion of a nonionic surfactant, in an amount in the range 1.5%-25% by weight, referred to the fluoropolymer weight; b) addition to the dispersion of a salt, soluble in water and not giving precipitates in the dispersion under the use conditions; c) contact of the dispersion with a basic anionic exchanger; d) separation of the dispersion from the basic anionic exchanger; before step d) the dispersion being filterable on a 180 micrometer net and successively on a 10 micrometer net.

Abstract: Dispersions of fluorinated polymers substantially free from fluorinated surfactants, having high stability to shear combined with high stability to segregation, said dispersions comprising one or more anionic surfactants having the following general formula (1): Y?—(P1)n—CH(Y)—(P2)n?—Y? ??(1) wherein: Y, Y? and Y? are anionic or nonionic groups, with the proviso that at least one of Y, Y? or Y? is an anionic group and at least one of the remaining of Y, Y? or Y? is a nonionic group; p1 and p2, equal or different, are linear or branched alkylene groups, optionally containing one or more unsaturations, having a number of carbon atoms from 1 to 10, preferably from 1 to 6; n and n? equal or different, are zero or 1.

Abstract: A process for preparing fluoropolymer dispersions, substantially free from anionic fluorinated surfactants, and with a coagulum amount <0.1% by weight, comprising: a) step a1) addition of: a non ionic surfactant having cloud point (CP) between 40° and 80° C., in an amount from 1.5% to 50% by weight on the dispersion fluoropolymer; and optionally an electrolyte to bring the specific conductivity of the dispersion to values in the range 130-8,000 ?S/cm; optionally a buffer agent to have a pH between 2 and 12 to a fluoropolymer dispersion obtainable by an emulsion polymerization process; step a2): heating of the dispersion obtained in a1) up to a temperature Tc in the range CP±10° C.; decantation without stirring, at the temperature Tc, until obtaining the dispersion separation in two aqueous phases, of which the lower one containing the fluoropolymer is discharged; b) step b1): the dispersion obtained in step a2) is optionally additioned of an electrolyte and of a non ionic surfactant as in a1).

Abstract: Fluoropolymer aqueous dispersions having particles with average diameters from 150 to 400 nm, comprising bifunctional fluorinated surfactants having formula: A-Rf—B??(I) wherein: A and B, equal to or different from each other, are: —(O)pCFX—COOM; M=NH4, alkaline metal, H; X=F, CF3; p is an integer equal to 0 or 1; 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 300-1,800.

Abstract: Fluoropolymer aqueous dispersions having particles with average diameters from 150 to 400 nm, comprising bifunctional fluorinated surfactants having formula: