##STR00001##

The copolymer includes divalent units represented by formula [CF.sup.2-CF.sup.2], divalent units represented by formula: (I), and one or more divalent units independently represented by formula: (II) When Z is hydrogen, the copolymer has an alpha transition temperature of up to 100 ?C. The copolymer has an SO.sub.3Z equivalent weight in a range from 300 to 1400, and a variation of the copolymer in which SO.sub.3Z is replaced with SO.sub.2F has a melt flow index of up to 80 grams per ten minutes measured at a temperature of 265 C. and at a support weight of 5 kg. A catalyst ink or polymer electrolyte membrane including the copolymer are also provided.

The copolymer includes divalent units represented by formula [CF.sub.2CF.sub.2], divalent units represented by formula: and one or more divalent units independently represented by formula: The copolymer has an SO.sub.2X equivalent weight in a range from 300 to 2000. A polymer electrolyte membrane that includes the copolymer and a membrane electrode assembly that includes such a polymer electrolyte membrane are also provided.

The fluoropolymer dispersion includes a copolymer having divalent units represented by formula [CF.sub.2CF.sub.2], divalent units represented by formula: [Formula should be inserted here], and one or more divalent units independently represented by formula: [Formula should be inserted here] dispersed in at least one of water or organic solvent. Methods of making the fluoropolymer dispersion and methods of using the fluoropolymer to make a at least one of a catalyst ink or polymer electrolyte membrane are also provided.

##STR00001##

A composition including a fluorine-containing polymer and a silicon-containing compound, wherein the phosphorus content in the composition is 20 ppm or less. Also disclosed is a molded article obtained from the composition, and a second composition containing a fluorine-containing polymer and a silicon-containing polymer, wherein a content of an amide solvent in the composition is less than 1000 ppm.

Described herein is a peroxide curable, partially fluorinated polymer derived from: (a) comonomers comprising: (i) 5-28 wt. % of tetrafluoroethylene; (ii) 30-70 wt. % of vinylidene fluoride; and (iii) a monomer selected from 10-45 wt. % of hexafluoropropylene and 10-40 wt, % of a perfluoro ether monomer of the formula R.sub.f-0-(CF.sub.2).sub.nCFCF.sub.2 wherein n is 1 or 0, and Rf represents a perfluoroalkyl residue which may or may not be interrupted by one or more than one oxygen atoms; (b) 0.01-2 wt % of a perfluorinated iodinated vinyl ether based on the total amount of comonomer, wherein the perfluorinated iodinated vinyl ether has the formula: F.sub.2CCF(CF.sub.2).sub.m(0).sub.o(CF.sub.2).sub.nO(CF.sub.2).sub.pI where m is 0 or 1; n is an integer of 0-5: o is 0 or 1: and p is an integer of 1-5, wherein when n is 0, o is 0; and (c) 0.01-2 wt % of a chain transfer agent based on the total amount of comonomers wherein the chain transfer agent consists of a diiodo-fluoroalkane and a diiodo-methane. Further described are methods of making the curable partially fluorinated polymers and articles comprising the cured fluoropolymer.

A copolymer includes a repeating unit of Formula (I) and a repeating unit of Formula (II), a composition includes the copolymer, and an optical film has a layer formed of the composition,

##STR00001##

in the Formulae (I) and (II), R.sup.1 and R.sup.2 represent a hydrogen atom or an alkyl group, L.sup.3 and L.sup.1 represent a divalent linking group, L.sup.2 represents a single bond or a divalent linking group, and L.sup.4 represents a single bond or a divalent linking group, L.sup.4 does not represent a linking group including O(CO)NH, X represents a perfluoropolyether group, an alkyl group having a branched structure in which hydrogen is all substituted into fluorine, an alkenyl group, or an alkynyl group, and Y represents a crosslinking group.

A curable composition capable of being cured at a low temperature of from room temperature to 150 C. is provided. The curable composition comprises a fluorinated polymer containing at least three functional groups represented by the following formula (F) and at least one curing agent selected from the group consisting of an isocyanate-type curing agent, a blocked isocyanate-type curing agent and an amino resin-type curing agent:

R.sup.f1COZ.sup.1 (F) (in the formula (1), R.sup.f1 is a fluoroalkylene group, or a fluoroalkylene group with at least two carbon atoms having an etheric oxygen atom between carbon-carbon atoms, Z.sup.1 is NR.sup.1NR.sup.2H or NR.sup.3OR.sup.4, and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently a hydrogen atom or an alkyl group.)

To provide a method for producing a fluorinated polymer, in which it is possible to efficiently and easily control the molecular weight to be proper when polymerizing a perfluoromonomer having a dioxolane ring containing a polymerizable double bond in the ring skeleton, and in which the obtainable fluorinated polymer is less susceptible to a decrease in molecular weight even when contacted with a base. A method for producing a fluorinated polymer, comprising polymerizing a raw-material mixture which contains at least one of a monomer composition M11 which comprises a perfluoromonomer represented by the formula m11 and a fluorinated monomer m11H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, and a monomer composition M12 which comprises a perfluoromonomer represented by formula m12 and a fluorinated monomer m12H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, wherein the total amount of the fluorinated monomer mil H and the fluorinated monomer m12H is from 10 to 1,100 ppm to the total amount of the monomer composition M11 and the monomer composition M12. ##STR00001##

The invention pertains to certain fluoroelastomer compositions comprising an iodine-containing (per)fluoroelastomer of low molecular weight and certain organic peroxides, possessing outstanding cross-linking behaviour at limited temperatures, and yielding resulting final parts exhibiting good mechanical and sealing properties, while avoiding discoloring/degradation phenomena, and enabling easy colour match in a wide range of colours.

Electronic telecommunication articles are described comprising a layer of fluoropolymer composition comprising a fluoropolymer or fluoropolymer blend comprising at least 1 wt. % and less than 30 wt. % of polymerized units of unsaturated (per)fluorinated alkyl ether(s). Also described are methods of making a coated substrate, a substrate comprising a fluoropolymer composition, and fluoropolymer compositions.