Polymer electrolytes and process for their production

Abstract

Polymer electrolytes and process for their preparation A sulfonated aromatic polyether ketone of the formula (II) [Ar—O—Ar′—CO—Ar′—O—Ar—CO—Ar″—CO—]  (II) in which from 1% to 100% of the O-phenylene-CO units are substituted with an SO 3 M group and sulfonated and unsulfonated O-phenylene-CO units can be in any desired sequence with respect to one another, the radicals Ar, Ar′ and Ar″ independently of one another are substituted or unsubstituted 1,2-, 1,3- or 1,4-phenylene rings, and M, taking into account the ionic valencies, comprises one or more elements selected from the following group: H, NR 4 + , where R is H or C 1 -C 4 -alkyl, or an alkali metal or alkaline earth metal or a metal from subgroup 8, and is preferably H, NR 4 + , Li, Na, K, Ca, Mg, Fe or Pt.

1 . A sulfonated aromatic polyether ketone of the formula (II)  
       [Ar—O—Ar′—CO—Ar′—O—Ar—CO—Ar″—CO—]  (II)  
       in which from 1% to 100% of the O-phenylene-CO units are substituted with an SO 3 M group and sulfonated and unsulfonated O-phenylene-CO units can be in any desired sequence with respect to one another, the radicals Ar, Ar′ and Ar″ independently of one another are substituted or unsubstituted 1,2-, 1,3- or 1,4-phenylene rings, and  
       M, taking into account the ionic valencies, comprises one or more elements selected from the following group: H, NR 4   + , where R is H or C 1 -C 4 -alkyl, or an alkali metal or alkaline earth metal or a metal from subgroup 8, and is preferably H, NR 4   + , Li, Na, K, Ca, Mg, Fe or Pt.  
     
     
         2 . A process for the preparation of a polyether ketone of the formula (II) in which Ar, Ar′ and Ar″ are as defined in  claim 1  by dissolving the corresponding unsulfonated polyether ketone of the formula (II) in from 94 to 97% strength by weight sulfuric acid, adding a sulfonating agent to the solution thus obtained, at an appropriate temperature, and working up the reaction mixture as soon as the desired degree of sulfonation has been reached, and, if desired, converting the sulfonic acid groups into their salt form.  
     
     
         3 . The process as claimed in  claim 2 , wherein the dissolution temperature is in the range from 10 to 80° C.  
     
     
         4 . The process as claimed in  claim 2 , wherein the sulfonation temperature is in the range from 10 to 100° C.  
     
     
         5 . The process as claimed in  claim 2 , wherein following addition of the sulfonating agent the temperature of the solution is at least 30° C.  
     
     
         6 . The process as claimed in  claim 2 , wherein the sulfonating agent used is sulfuric acid, fuming sulfuric acid, oleum, chlorosulfonic acid, sulfur trioxide or a mixture of these compounds.  
     
     
         7 . The process as claimed in  claim 2 , wherein oleum is added to the polyether ketone, dissolved in sulfuric acid, until the concentration of sulfuric acid is from 98 to 100% by weight or the concentration of oleum is from 0.01 to 15% by weight of SO 3 .  
     
     
         8 . The process as claimed in  claim 2 , wherein a polyether ketone of the formula (I) is dissolved in from 95 to 97% strength by weight sulfuric acid at not more than 80° C. and is sulfonated at temperatures of from 50 to 100° C.  
     
     
         9 . A process for the preparation of a sulfonated polyether ketone by dissolving the polyether ketone in from 94 to 97% strength by weight sulfuric acid, sulfonating the polyether ketone in sulfuric acid, fuming sulfuric acid, oleum, chlorosulfonic acid or a mixture thereof and working up the reaction mixture as soon as the desired degree of sulfonation has been reached, wherein from 1 to 100% of the O-phenylene-CO units are substituted with an SO 3 M group.  
     
     
         10 . A polymer electrolyte solution comprising a sulfonated aromatic polyether ketone of formula (II).  
     
     
         11 . The polymer electrolyte solution as claimed in  claim 10 , which comprises at least 1% by weight of sulfonated polyether ketones of the formula (II).  
     
     
         12 . The polymer electrolyte solution as claimed in  claim 10 , whose principal constituent is an aprotic dipolar solvent, for example N-methylpyrrolidone or dimethyl sulfoxide.  
     
     
         13 . The polymer electrolyte solution as claimed in  claim 10 , which comprises a further, sulfonated or unsulfonated polymer and, if desired, small quantities of auxiliaries.  
     
     
         14 . The use of a polymer electrolyte solution as claimed in  claims 10  to  13  for preparing asymmetric membranes, for example for nano-, ultra- or microfiltration.  
     
     
         15 . The use of a polymer electrolyte solution as claimed in  claims 10  to  13  for preparing cohesive films.  
     
     
         16 . The use of a polymer electrolyte solution as claimed in  claims 10  to  13  for establishing particularly intensive contact between two polymer electrolyte surfaces.  
     
     
         17 . The use of a polymer electrolyte solution as claimed in  claims 10  to  13  for achieving a porous or rough surface after contacting the solution with a precipitating agent.  
     
     
         18 . The use of a polymer as claimed in  claim 1  for preparing a polymer electrolyte solution and/or for preparing a polymer film.  
     
     
         19 . The use of a polymer as claimed in  claim 1  and/or  18  in electrochemical cells.  
     
     
         20 . The use as claimed in  claim 19 , wherein the electrochemical cell is a fuel cell or an electrolyzer.  
     
     
         21 . A film having a thickness of from 5 μm to 1 mm, which comprises a polyether ketone as claimed in  claim 1.