A fluororesin having a tensile strength retention ratio of 50% or more, the tensile strength retention ratio being calculated by the following formula from the tensile strength of the fluororesin after a heat treatment obtained by conducting a heat treatment at 130° C. for 40,000 hours, and the tensile strength of the fluororesin before the heat treatment. Tensile strength retention ratio (%)=(tensile strength of fluororesin after heat treatment (MPa))/(tensile strength of fluororesin before heat treatment (MPa))×100.

Provided is a molded body with a hollow portion comprising tetrafluoroethylene and perfluoro(alkyl vinyl ether) copolymer, which is obtained by heat treating a molded body with a hollow portion obtained by melt molding tetrafluoroethylene and perfluoro(alkyl vinyl ether) copolymer having a melt flow rate of 0.1 to 100 g/10 min when measured with a load of 5 kg and a measurement temperature of 372±0.1° C. in accordance with ASTM D1238. The heat treatment is carried out at a temperature from 130° C. below the melting point of the copolymer to the melting point of the copolymer. The molded body exhibits excellent blister resistance when utilized in contact with harsh chemicals and under harsh operating conditions.

The present disclosure relates to a composition that includes a fluoropolymer, a polymerized ionic liquid block copolymer (PILBC), and a catalyst, where the fluoropolymer is configured to affect ionic mobility, and the PILBC is configured to affect a property of the catalyst. In some embodiments of the present disclosure, the property may include at least one of oxygen transport and/or an active site functionality of the catalyst.

The present disclosure relates to a composition that includes a fluoropolymer, a polymerized ionic liquid block copolymer (PILBC), and a catalyst, where the fluoropolymer is configured to affect ionic mobility, and the PILBC is configured to affect a property of the catalyst. In some embodiments of the present disclosure, the property may include at least one of oxygen transport and/or an active site functionality of the catalyst.

The present invention aims to provide a method of producing a fluoropolymer, especially a fluoropolymer essentially including a tetrafluoroethylene or chlorotrifluoroethylene unit, at a higher polymerization rate with improved efficiency, the method being capable of improving the moldability in extrusion molding and suppressing discoloration. The method of producing a fluoropolymer of the present invention includes producing a fluoropolymer by polymerizing tetrafluoroethylene or chlorotrifluoroethylene in the presence of a peroxydicarbonate. The peroxydicarbonate is represented by the formula:
R—O—C(═O)—O—O—C(═O)—O—R
wherein R's may be the same as or different from each other and individually represent a C4 alkyl group or alkoxy alkyl group.

The invention provides a laminate including a fluoroelastomer layer and a fluororesin layer which are firmly bonded to each other. The laminate includes a fluoroelastomer layer (A) and a fluororesin layer (B) stacked on the fluoroelastomer layer (A). The fluoroelastomer layer (A) is a layer formed from a fluoroelastomer composition. The fluoroelastomer composition contains a fluoroelastomer, a basic multifunctional compound, and at least one compound (a) selected from the group consisting of a fluororesin (a1) and a phosphorus compound (a2). The compound (a) is present in an amount of 0.01 to 120 parts by mass relative to 100 parts by mass of the fluoroelastomer. The fluororesin layer (B) is formed from a fluororesin (b1) having a fuel permeability coefficient of 2.0 g.Math.mm/m.sup.2/day or lower.

A film containing a resin composition containing an aromatic polyetherketone resin (I) and a fluorine-containing copolymer (II). The fluorine-containing copolymer (II) defines a dispersed phase at an average dispersed particle size of 5 .Math.m or smaller. The aromatic polyetherketone resin (I) has a crystallinity of lower than 6%.

A film containing a resin composition containing an aromatic polyetherketone resin (I) and a fluorine-containing copolymer (II). The fluorine-containing copolymer (II) defines a dispersed phase at an average dispersed particle size of 5 .Math.m or smaller. The aromatic polyetherketone resin (I) has a crystallinity of lower than 6%.

The copolymer includes divalent units represented by formula —[CF.sub.2—CF.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 copolymer includes divalent units represented by formula —[CF.sub.2—CF.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.