Graft polymeric membranes and ion-exchange membranes formed therefrom

Abstract

Graft polymeric membranes and methods for making graft polymeric membranes have one or more trifluorovinyl aromatic monomers that are radiation graft polymerized to a polymeric base film. The membranes comprise a polymeric base film to which has been graft polymerized substituted α,α,β-trifluorostyrene and/or α,α,β-trifluorovinylnaphthylene monomers, which are activated towards graft polymerization. As ion-exchange membranes, the membranes are suitable for use in electrode apparatus, including membrane electrode assemblies in, for example, fuel cells. The membranes can also be crosslinked.

1 . A membrane comprising a polymeric base film to which has been graft polymerized a monomer selected from the group consisting of monomers of formula (I)  
       
         
           
           
               
               
           
         
       
       and formula (II)  
       
         
           
           
               
               
           
         
       
       where A 1 , A 2 , and B 1 , B 2  are independently selected from the group of consisting of: 
 hydrogen, lower alkyl, lower fluoroalkyl, cyclic alkyl,  
 cyclic amine, cyclic ether, cyclic thioether,  
 Ar, wherein Ar is other than Ph when one of A 1  and A 2  is hydrogen,  
 CH(X)Ph, where X is selected from the group consisting of hydrogen, fluorine, lower alkyl, lower fluoroalkyl and Ph,  
 PRR′ and P(OR)(OR′), where R and R′ are independently selected from the group consisting of lower alkyl, cyclic alkyl and Ph, and  
 wherein at least one of substituents A 1 , A 2 , B 1  and B 2  is other than hydrogen.  
 
     
     
         2 - 36 . (Cancelled).  
     
     
         37 . A membrane comprising a polymeric base film with grafted chains comprising monomer units selected from the group consisting of monomer units of formula (IV)  
       
         
           
           
               
               
           
         
       
       and formula (V)  
       
         
           
           
               
               
           
         
       
       where A 1 , A 2 , and B 1 , B 2  are independently selected from the group consisting of: 
 hydrogen, lower alkyl, lower fluoroalkyl, cyclic alkyl,  
 cyclic amine, cyclic ether, cyclic thioether,  
 Ar, wherein Ar is other than Ph when one of A 1  and A 2  is hydrogen,  
 CH(X)Ph, where X is selected from the group consisting of hydrogen, fluorine, lower alkyl, lower fluoroalkyl and Ph,  
 PRR′ and P(OR)(OR′), where R and R′ are independently selected from the group consisting of lower alkyl, cyclic alkyl and Ph,  
 and wherein at least one of substitutents A 1 , A 2 , B 1  and B 2  is other than hydrogen.  
 
     
     
         38 - 68 . (Cancelled).  
     
     
         69 . A method of preparing a membrane, the method comprising graft polymerizing to a polymeric base film a monomer selected from the group consisting of monomers of formula (I)  
       
         
           
           
               
               
           
         
       
       and formula (II)  
       
         
           
           
               
               
           
         
       
       wherein, in the selected monomer, at least one of substitutents A 1 , A 2 , and B 1 , B 2  is a non-hydrogen substituent that activates said monomer with respect to said graft polymerization, and said method further comprises: 
 introducing a sulfonate group into at least a portion of said graft polymerized monomer units; and  
 converting at least a portion of said non-hydrogen substituents to substituents that are deactivating with respect to desulfonation.  
 
     
     
         70 . A method of preparing a membrane, said method comprising graft polymerizing to a polymeric base film a monomer selected from the group consisting of monomers of formula (I)  
       
         
           
           
               
               
           
         
       
       and formula (II)  
       
         
           
           
               
               
           
         
       
       where A 1 , A 2 , and B 1 , B 2  are independently selected from the group consisting of: 
 hydrogen, lower alkyl, lower fluoroalkyl, cyclic alkyl,  
 cyclic amine, cyclic ether, cyclic thioether,  
 Ar, wherein Ar is other than Ph when one of A 1  and A 2  is hydrogen,  
 CH(X)Ph, where X is selected from the group consisting of hydrogen, fluorine, lower alkyl, lower fluoroalkyl and Ph,  
 PRR′ and P(OR)(OR′), where R and R′ are independently selected from the group consisting of lower alkyl, cyclic alkyl and Ph, and  
 wherein at least one of substitutents A 1 , A 2 , B 1  and B 2  is other than hydrogen.  
 
     
     
         71 - 80 . (Cancelled).  
     
     
         81 . A method of preparing a membrane comprising graft polymerizing to a polymeric base film a monomer selected from the group consisting of monomers of formula (I)  
       
         
           
           
               
               
           
         
       
       and formula (II)  
       
         
           
           
               
               
           
         
       
       where A 1  and B 1  are independently selected from the group consisting of: 
 PRR′, P(OR)(OR′), and SR, where R and R′ are independently selected from the group consisting of lower alkyl, cyclic alkyl and Ph, and  
 A 2  is selected from the group consisting of A 1  and hydrogen, and B 2  is selected from the group consisting of B 1  and hydrogen,  
 the method further comprising subjecting at least a portion of one of the PRR′, the P(OR)(OR′) and the SR groups to oxidation.  
 
     
     
         82 - 85 . (Cancelled).