Crosslinked fluoropolymer networks
View Patent ↗Disclosed herein is a crosslinked fluoropolymer network formed by the free radical initiated crosslinking of a diacrylate fluoropolymer The diacrylate copolymer is of formula CH 2 ═CR′COO—(CH 2 ) n —R—(CH 2 ) n —OOCR′═CH 2 , wherein R is selected from the group consisting of i) an oligomer comprising copolymerized units of vinylidene fluoride and perfluoro(methyl vinyl ether), ii) an oligomer comprising copolymerized units of vinylidene fluoride and hexafluoropropylene, iii) an oligomer comprising copolymerized units of tetrafluoroethylene and perfluoro(methyl vinyl ether), and iv) an oligomer comprising copolymerized units of tetrafluoroethylene and a hydrocarbon olefin, R′ is H or —CH 3 , n is 1-4 and wherein said oligomer has a number average molecular weight of 1000 to 25,000 daltons. The source of the free radicals may be a photoinitiator or an organic peroxide.
1. A process for the manufacture of a crosslinked fluoropolymer network, said process comprising:
A) providing a telechelic diacrylate copolymer of formula CH 2 ═CR′COO—(CH 2 ) n —R—(CH 2 ) n —OOCCR′═CH 2 , wherein R′ is H or —CH 3 , n is 2 or 3 and R is an oligomer having a number average molecular weight of 1000 to 25,000 daltons, said oligomer selected from the group consisting of i) an oligomer comprising copolymerized units of vinylidene fluoride and perfluoro(methyl vinyl ether), ii) an oligomer comprising copolymerized units of vinylidene fluoride and hexafluoropropylene, iii) an oligomer comprising copolymerized units of tetrafluoroethylene and perfluoro(methyl vinyl ether), and iv) an oligomer comprising copolymerized units of tetrafluoroethylene and a hydrocarbon olefin;
B) mixing said diacrylate copolymer with a source of free radicals selected from the group consisting of photoinitiators and organic peroxides to form a curable composition; and
C) generating free radicals to form a crosslinked fluoropolymer network.
2. A process of claim 1 wherein said oligomer has a number average molecular weight of 1200 to 12,000 daltons.
3. A process of claim 2 wherein said oligomer has a number average molecular weight of 1500 to 5000 daltons.
4. A process of claim 1 wherein said oligomer comprises copolymerized units selected from the group consisting of i) vinylidene fluoride, tetrafluoroethylene and perfluoro(methyl vinyl ether); ii) tetrafluoroethylene, perfluoro(methyl vinyl ether) and ethylene; iii) vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene; and iv) tetrafluoroethylene, vinylidene fluoride and propylene.
5. A process of claim 1 wherein said source of free radicals is a photoinitiator and free radicals are generated by exposing said curable composition to UV light.