A method for producing a fluoropolymer powder including (A1) adding, to a fluoropolymer aqueous dispersion obtained by polymerization using a carboxylic acid type hydrocarbon surfactant, and an acid to adjust a pH to 4.0 or less and cause coagulation to thereby obtain a wet fluoropolymer powder containing a fluorine-containing compound represented by the following general formula (1A), and (B1) heat-treating the wet fluoropolymer powder at a temperature higher than 150° C. and lower than 240° C.: General Formula (1A): H—(CF.sub.2).sub.m—COOH wherein m is 3 to 19.

A method for producing a fluoropolymer powder including (A1) adding, to a fluoropolymer aqueous dispersion obtained by polymerization using a carboxylic acid type hydrocarbon surfactant, and an acid to adjust a pH to 4.0 or less and cause coagulation to thereby obtain a wet fluoropolymer powder containing a fluorine-containing compound represented by the following general formula (1A), and (B1) heat-treating the wet fluoropolymer powder at a temperature higher than 150° C. and lower than 240° C.: General Formula (1A): H—(CF.sub.2).sub.m—COOH wherein m is 3 to 19.

A method for producing a composition containing low molecular weight polytetrafluoroethylene, the method including: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×10.sup.2 to 7.0×10.sup.5 Pa.Math.s; and (II) carrying out at least one selected from the group consisting of washing treatment, steam treatment and decompression treatment on the composition containing low molecular weight polytetrafluoroethylene.

A method for producing a composition containing low molecular weight polytetrafluoroethylene, the method including: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×10.sup.2 to 7.0×10.sup.5 Pa.Math.s; and (II) carrying out at least one selected from the group consisting of washing treatment, steam treatment and decompression treatment on the composition containing low molecular weight polytetrafluoroethylene.

A method for producing a composition containing low molecular weight polytetrafluoroethylene, the method including: (I) irradiating a composition containing high molecular weight polytetrafluoroethylene with ionizing radiation to obtain a composition containing low molecular weight polytetrafluoroethylene having a melt viscosity at 380° C. in the range of 1.0×10.sup.2 to 7.0×10.sup.5 Pa.Math.s; and (II) carrying out at least one selected from the group consisting of washing treatment, steam treatment and decompression treatment on the composition containing low molecular weight polytetrafluoroethylene.

The present invention discloses a process for polymerizing fluoromonomers in an aqueous medium to form a fluoropolymer, said process comprising the steps of: (a) forming an aqueous solution comprising a first surfactant combination of at least one fluorinated surfactant and at least one non-10 fluorinated surfactant in a polymerization reactor; (b) pressurizing the polymerization reactor with said fluoromonomers; (c) initiating a polymerization reaction of said fluoromonomers to form said fluoropolymer; (d) propagation of said polymerization reaction, wherein a second surfactant combination of at least one fluorinated surfactant and at least one non-fluorinated surfactant is 15 metered or one shot dosed into the polymerization reactor; and (e) termination of said polymerization reaction after consumption of a desired quantity of said fluoromonomers.

The present invention discloses a process for polymerizing fluoromonomers in an aqueous medium to form a fluoropolymer, said process comprising the steps of: (a) forming an aqueous solution comprising a first surfactant combination of at least one fluorinated surfactant and at least one non-10 fluorinated surfactant in a polymerization reactor; (b) pressurizing the polymerization reactor with said fluoromonomers; (c) initiating a polymerization reaction of said fluoromonomers to form said fluoropolymer; (d) propagation of said polymerization reaction, wherein a second surfactant combination of at least one fluorinated surfactant and at least one non-fluorinated surfactant is 15 metered or one shot dosed into the polymerization reactor; and (e) termination of said polymerization reaction after consumption of a desired quantity of said fluoromonomers.

Provided in this patent disclosure are two types of novel fluoro-monomers that can be polymerized for the fabrication of ion-exchange fluoropolymers. In addition, new proton-conductive zirconium-perfluorophosphonic acid fluoropolymer membranes that can reduce metal crossovers in redox flow batteries are also provided.

Provided in this patent disclosure are two types of novel fluoro-monomers that can be polymerized for the fabrication of ion-exchange fluoropolymers. In addition, new proton-conductive zirconium-perfluorophosphonic acid fluoropolymer membranes that can reduce metal crossovers in redox flow batteries are also provided.

A modified polytetrafluoroethylene aqueous dispersion having low viscosity at high temperature. The modified polytetrafluoroethylene aqueous dispersion contains a modified polytetrafluoroethylene and a nonionic surfactant, has a modified polytetrafluoroethylene solid concentration of 50 to 70% by mass, is substantially free from a fluorine-containing surfactant, and has a viscosity at 55° C. of 80 mPa•s or lower, and the modified polytetrafluoroethylene contains 0.050% by mass or more and 1.00% by mass or less of a polymerized unit based on a modifying monomer.