Fluorinated ionomers with reduced amounts of carbonyl end groups

Abstract

The present invention is a fluoropolymer comprising a plurality of pendent groups terminating in —CF 2 SO 3 X, —CF 2 SO 2 F, or combinations thereof, where X is selected from a group consisting of H + and a monovalent cation, and at least one —CF 2 Y end group, where Y is selected from a group consisting of a chlorine atom, a bromine atom, an iodine atom, a nitrile group, and an —SO 3 X group.

1 . A fluoropolymer comprising: 
 a plurality of pendent groups terminating in —CF 2 SO 3 X, —CF 2 SO 2 F, or combinations thereof, wherein X is selected from a group consisting of H +  and a cation; and    at least one —CF 2 Y end group, wherein Y is selected from a group consisting of a chlorine atom, a bromine atom, an iodine atom, a nitrile group, and an —SO 3 X group.    
     
     
         2 . The fluoropolymer of  claim 1 , wherein Y comprises the chlorine atom or the —SO 3 X group.  
     
     
         3 . The fluoropolymer of  claim 1 , wherein the fluoropolymer has at least about 25% fewer carbonyl end groups relative to a similar fluoropolymer produced in the absence of a salt or a pseudohalogen.  
     
     
         4 . The fluoropolymer of  claim 1 , further comprising a perfluorinated backbone chain.  
     
     
         5 . The fluoropolymer of  claim 1 , wherein the pendent groups are selected from a group consisting of —O(CF 2 ) 4 SO 2 X, —O(CF 2 ) 4 SO 2 F, —OCF 2 CF(CF 3 )OCF 2 CF 2 SO 2 X, —OCF 2 CF(CF 3 )OCF 2 CF 2 SO 2 F, and combinations thereof.  
     
     
         6 . An electrolyte membrane comprising the fluoropolymer of  claim 1 .  
     
     
         7 . The electrolyte membrane of  claim 6 , wherein the electrolyte membrane is cross-linked.  
     
     
         8 . An electrolyte membrane comprising being formed in part from fluoropolymers, wherein each of the fluoropolymers comprises: 
 a plurality of pendent groups terminating in —CF 2 SO 3 X, wherein X is selected from a group consisting of H +  and a cation; and    at least one —CF 2 Y end group, wherein Y is selected from a group consisting of a chlorine atom and an —SO 3 X group.    
     
     
         9 . The electrolyte membrane of  claim 8 , wherein the fluoropolymers have at least about 25% fewer carbonyl end groups relative to similar fluoropolymers produced in the absence of a salt or a pseudohalogen.  
     
     
         10 . An electrochemical device comprising the electrolyte membrane of  claim 8 .  
     
     
         11 . A method of making a fluoropolymer, the method comprising free-radical polymerizing fluorinated monomers in the presence of a salt, a pseudohalogen, or a combination of the salt and the pseudohalogen, to make the fluoropolymer, wherein the fluoropolymer comprises a plurality of pendent groups terminating in —CF 2 SO 2 F and at least one —CF 2 Y end group, wherein Y is selected from a group consisting of a chlorine atom, a bromine atom, an iodine atom, a nitrile group, and an —SO 3 X group, wherein X is selected from a group consisting of H +  and a cation.  
     
     
         12 . The fluoropolymer of  claim 11 , wherein the fluoropolymer has at least about 25% less carbonyl end groups relative to a similar fluoropolymer produced in the absence of the salt or the pseudohalogen.  
     
     
         13 . The method of  claim 11 , further comprising hydrolyzing the fluoropolymer, wherein the hydrolyzing substantially converts the pendent groups terminating in —CF 2 SO 2 F to pendent groups terminating in —CF 2 SO 3 X.  
     
     
         14 . The method of  claim 11 , further comprising post-fluorinating the fluoropolymer, where the post-fluorinating substantially converts the —CF 2 Y end group to a —CF 3  end group.  
     
     
         15 . The method of  claim 14 , further comprising hydrolyzing the fluoropolymer, wherein the hydrolyzing substantially converts the pendent groups terminating in —CF 2 SO 2 F to pendent groups terminating in —CF 2 SO 3 X.  
     
     
         16 . The method of  claim 11 , wherein the free-radical polymerizing also takes place in the presence of one or more disulphites.  
     
     
         17 . The method of  claim 11 , wherein the free-radical polymerizing also takes place in the presence of one or more compounds selected from a groups consisting of fluoroalkylsulfinates, fluoroalkylsulfinic acids, and combinations thereof.  
     
     
         18 . A method of making a fluoropolymer, the method comprising: 
 providing fluorinated monomers, wherein at least one of the fluorinated monomers comprises a sulfonyl fluoride monomer; and    free-radical reacting the fluorinated monomers in the presence of a salt, a pseudohalogen, or a combination of the salt and the pseudohalogen, to make the fluoropolymer, wherein the fluoropolymer has at least about 25% less carbonyl end groups relative to a similar fluoropolymer produced in the absence of the salt or the pseudohalogen.    
     
     
         19 . The method of  claim 18 , wherein fluoropolymer comprises a plurality of pendent groups terminating in —CF 2 SO 2 F.  
     
     
         20 . The method of  claim 19 , further comprising hydrolyzing the fluoropolymer such that the fluoropolymer comprises plurality of pendent groups terminating in —CF 2 SO 3 X, wherein X is selected from a group consisting of H+and a monovalent cation.  
     
     
         21 . The method of  claim 18 , further comprising post-fluorinating the fluoropolymer.