There is provided a fluorine-containing copolymer comprising tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(ethyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 9.5 to 11.6% by mass with respect to the whole of the monomer units, a content of the perfluoro(ethyl vinyl ether) unit of 1.2 to 2.9% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 19.0 to 28.0 g/10 min, and a total number of —CF.sub.2H, carbonyl group-containing terminal groups, —CF═CF.sub.2 and —CH.sub.2OH of 90 or less per 10.sup.6 main-chain carbon atoms.

There is provided a fluorine-containing copolymer comprising tetrafluoroethylene unit, hexafluoropropylene unit and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 9.4 to 10.3% by mass with respect to the whole of the monomer units, a content of the perfluoro(propyl vinyl ether) unit of 1.6 to 2.9% by mass with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 22.0 to 40.0 g/10 min.

There is provided a fluorine-containing copolymer comprising tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 3.55 to 4.10% by mol with respect to the whole of the monomer units, a content of the perfluoro(propyl vinyl ether) unit of 0.39 to 0.90% by mol with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 1.0 to 9.0 g/10 min.

There is provided a fluorine-containing copolymer comprising tetrafluoroethylene unit, hexafluoropropylene unit and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 6.0 to 7.6% by mass with respect to the whole of the monomer units, a content of the perfluoro(propyl vinyl ether) unit of 1.5 to 2.4% by mass with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 4.5 to 9.5 g/10 min.

There is provided a fluorine-containing copolymer containing tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 10.3 to 12.0% by mass with respect to the whole of the monomer units, a content of the perfluoro(propyl vinyl ether) unit of 1.6 to 2.9% by mass with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 5.0 to 40.0 g/10 min.

Provided herein are copolymers that comprise copolymerized residues of a perfluorotrivinyltriazine monomer of Formula 1. ##STR00001## Preferred R.sub.f groups include, without limitation, —(CF.sub.2).sub.n— (n=1-6); —(CF.sub.2).sub.m—[OCF(CF.sub.3)CF.sub.2].sub.p— (m=1-4, p=1-4); and —[(CF(CF.sub.3)—O).sub.x—(CF.sub.2).sub.k]— (x=1-3, k=1-5). Preferred comonomers for copolymerization with the perfluorotrivinyltriazine monomer (1) include, without limitation, tetrafluoroethylene (TFE); vinylidene fluoride (VF2); hexafluoropropylene (HFP); vinyl fluoride (VF); EVE; PSEPVE; perfluoro-(long chain vinyl ethers); E; P; PFBE; PEVE; EVE-OH; EVE-P; PDD; and the cure-site monomers BTFB, ITFB, 8-CNVE, 8-SAVE, and the like. Also provided are methods of synthesizing the copolymers and articles comprising the copolymers.

Co-cured blends of fluoroelastomers of tetrafluoroethylene-propylene copolymer with cure site monomer and terpolymers of Vinylidene fluoride (VDF), Hexafluoropropylene (HFP) and Tetrafluoroethylene (TFE) with peroxide as initiator and coagent TAIC as crosslinker show improved curing performance, improved mechanical properties and improved compression set as well. The co-cured fluoroelastomers show improved chemical resistance to the solvent aging systems and better retention of mechanical properties after aging at high temperature in the solvents system.

There is provided a fluorine-containing copolymer containing tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of hexafluoropropylene unit of 9.5 to 12.2% by mass with respect to the whole of the monomer units, a content of perfluoro(propyl vinyl ether) unit of 0.5 to 1.4% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 0.8 to 4.0 g/10 min, and a number of —CF.sub.2H of more than 50 per 10.sup.6 main-chain carbon atoms.

There is provided a fluorine-containing copolymer comprising tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of the hexafluoropropylene unit of 9.4 to 10.3% by mass with respect to the whole of the monomer units, a content of the perfluoro(propyl vinyl ether) unit of 1.6 to 2.9% by mass with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 9.0 to 17.0 g/10 min.

There is provided a fluorine-containing copolymer containing tetrafluoroethylene unit, hexafluoropropylene unit, and perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of hexafluoropropylene unit of 10.3 to 12.2% by mass with respect to the whole of the monomer units, a content of perfluoro(propyl vinyl ether) unit of 1.2 to 1.6% by mass with respect to the whole of the monomer units, and a melt flow rate at 372° C. of 13.0 to 17.0 g/10 min.