A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorine-containing diacyl peroxide represented by the formula (1): XRf.sup.aC(═O)OOC(═O)Rf.sup.bY (wherein X and Y are each independently H or F; and Rf.sup.a and Rf.sup.b are each independently a C1-C6 linear or branched perfluoroalkylene group optionally containing an ether bond) and a fluorine-containing carboxylic acid represented by the following formula (2): Z.sup.2Rf.sup.cCOOH (wherein Z.sup.2 is H or F; and Rf.sup.c is a C1-C3 linear or branched perfluoroalkylene group optionally containing an ether bond when Z.sup.2 is H, and Rf.sup.c is a C1 or C2 linear or branched perfluoroalkylene group optionally containing an ether bond when Z.sup.2 is F) to provide a fluoropolymer.

A method for producing a fluoropolymer which includes polymerizing a fluoromonomer in an aqueous medium in the presence of a fluorine-containing diacyl peroxide represented by the formula (1): XRf.sup.aC(═O)OOC(═O)Rf.sup.bY (wherein X and Y are each independently H or F; and Rf.sup.a and Rf.sup.b are each independently a C1-C6 linear or branched perfluoroalkylene group optionally containing an ether bond) and a fluorine-containing carboxylic acid represented by the following formula (2): Z.sup.2Rf.sup.cCOOH (wherein Z.sup.2 is H or F; and Rf.sup.c is a C1-C3 linear or branched perfluoroalkylene group optionally containing an ether bond when Z.sup.2 is H, and Rf.sup.c is a C1 or C2 linear or branched perfluoroalkylene group optionally containing an ether bond when Z.sup.2 is F) to provide a fluoropolymer.

A member contains a fluorine-containing polymer and a fluorine-containing surfactant, in which provided that a mass-based content of the fluorine-containing surfactant in at least a surface of a portion of the member is M.sub.1, and a mass-based content of the surfactant in a position 10 nm below the surface in a thickness direction of the member is M.sub.2, M.sub.1/M.sub.2 is 0.50 to 0.90, and an atom number ratio X.sub.1 of the number of fluorine atoms contained in the surface to the number of carbon atoms contained in the surface is 0.50 to 3.0.

A member contains a fluorine-containing polymer and a fluorine-containing surfactant, in which provided that a mass-based content of the fluorine-containing surfactant in at least a surface of a portion of the member is M.sub.1, and a mass-based content of the surfactant in a position 10 nm below the surface in a thickness direction of the member is M.sub.2, M.sub.1/M.sub.2 is 0.50 to 0.90, and an atom number ratio X.sub.1 of the number of fluorine atoms contained in the surface to the number of carbon atoms contained in the surface is 0.50 to 3.0.

Microencapsulation methods are provided using encapsulant, fiber or film forming compositions of a cross-linkable anionic polymer, a multivalent cation salt, a chelating agent, and a volatile base. During the formation of this composition, the generally acidic chelating agent is titrated with a volatile base to an elevated pH to improve ion-binding capability. Multivalent cations are sequestered in cation-chelate complexes. Cross-linkable polymers in this solution will remain freely dissolved until some disruption of equilibrium induces the release of the free multivalent cations from the cation-chelate complex. Vaporization of the volatile base drops the pH of the solution causing the cation-chelate complexes to dissociate and liberate multivalent cations that associate with the anionic polymer to form a cross-linked matrix. During spray-drying, the formation of a wet particle, polymer cross-linking, and particle drying occur nearly simultaneously.

Microencapsulation methods are provided using encapsulant, fiber or film forming compositions of a cross-linkable anionic polymer, a multivalent cation salt, a chelating agent, and a volatile base. During the formation of this composition, the generally acidic chelating agent is titrated with a volatile base to an elevated pH to improve ion-binding capability. Multivalent cations are sequestered in cation-chelate complexes. Cross-linkable polymers in this solution will remain freely dissolved until some disruption of equilibrium induces the release of the free multivalent cations from the cation-chelate complex. Vaporization of the volatile base drops the pH of the solution causing the cation-chelate complexes to dissociate and liberate multivalent cations that associate with the anionic polymer to form a cross-linked matrix. During spray-drying, the formation of a wet particle, polymer cross-linking, and particle drying occur nearly simultaneously.

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.

Described herein are compositions and methods for stabilizing the ability of hydrated polyacrylamide co-polymers to modify the physical properties of water solutions under high shear conditions. The compositions generally include a water solution including at least one hydrated polyacrylamide co-polymer; and at least one additive selected from the group consisting of i) a component having the formula of Formula 1, where Formula 1 is R.sub.1—O-EO.sub.a-PO.sub.b-EO.sub.c—PO.sub.d—R.sub.2, where R.sub.1 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain; O is oxygen, EO.sub.a is —(CH.sub.2CH.sub.2—O).sub.a where a can be from 0-500; PO.sub.b is —(CH(CH.sub.3)CH.sub.2—O).sub.b where b can be from 0-70; EO.sub.c is —(CH.sub.2CH.sub.2—O).sub.c where c can be from 0-150; PO.sub.d is —CH(CH.sub.3)CH.sub.2—O).sub.d where d is from 0-30; and R.sub.2 is hydrogen or any C.sub.1 to C.sub.18 carbon or carbon chain; ii) a tetra functional block copolymer; iii) a polyvinylpyrrolidone (PVP) homopolymer; and iv) any combination thereof.

The present invention provides a perfluoroether fluororubber and a preparation method therefor and use thereof. The perfluoroether fluororubber is prepared by a stepwise polymerization method, wherein polymerization monomers in each step of polymerization comprise tetrafluoroethylene and a perfluoroalkyl vinyl ether. The preparation method for the perfluoroether fluororubber provided in the present invention can shorten polymerization time and improve production efficiency, and the finally obtained perfluoroether fluororubber is good in processability, high in strength, low in hardness and compression deformation and good in medium resistance.