Polymer Membranes

Abstract

The invention relates to novel organic/inorganic hybrid membranes which have the following composition: a polymer acid containing —SO 3 H, —PO 3 H 2 , —COOH or B(OH) 2 groups, a polymeric base (optional), which contains primary, secondary or tertiary amino groups, pyridine groups, imidazole, benzimidazole, triazole, benzotriazole, pyrazole or benzopyrazole groups, either in the side chain or in the main chain; an additional polymeric base (optional) containing the aforementioned basic groups; an element or metal oxide or hydroxide, which has been obtained by hydrolysis and/or sol-gel reaction of an elementalorganic and/or metalorganic compound during the membrane forming process and/or by a re-treatment of the membrane in aqueous acidic, alkaline or neutral electrolytes. The invention also relates to methods for producing said membranes and to various uses for membranes of this type.

1 . Membranes containing at least one polymeric acid, characterized in that before, during or after the membrane formation process salts, metal oxides or metal hydroxides or their organic precursors are incorporated into the membrane. 
     
     
         2 . Membranes according to  claim 1  containing at least one polymeric acid and at least one polymeric base characterized in that during or after the membrane formation process salts, metal oxides or metal hydroxides or their organic precursors are incorporated into the membrane. 
     
     
         3 . Membranes according to  claim 1  characterized in that the polymeric acid is an aryl main chain polymer and comprises as acidic groups SO 3 H—, PO 3 H 2 , COOH or B(OH) 2  or their salts and is chosen from the group of polyether sulfones, polysulfones, polyphenyl sulfones, polyetherether sulfones, polyether ketones, polyether ether ketones, polyphenylene ethers, polydiphenylphenylene ethers, polyphenylene sulfides or is a copolymer, that contains at least one of these components. 
     
     
         4 . Membranes according to  claim 1  characterized in that the polymeric bases contain primary, secondary or tertiary amino groups, pyridine groups, imidazole, benzimidazole, triazole, benzotriazole, pyrazole or benzopyrazole groups either in the side chain or the main chain. 
     
     
         5 . Membranes according to one or more claims of  1  to  4 , characterized in that they contain a salt, elemental oxide or elemental hydroxide or metal oxide or metal hydroxide, which has been obtained by hydrolysis and/or sol/gel reaction before, during or after membrane formation and is chosen from the following precursors:
 metal/element alkoxides/esters of Ti, Zr, Sn, Si, B, Al   metal acetylacetonates, e.g. Ti(acac) 4 , Zr(acac) 4      mixed compounds of metal/element alkoxides and   metal acetylacetonates, e.g. Ti(acac) 2 (OiPr) 2  etc.   organic amino compounds of Ti, Zr, Sn, Si, B, Al   
     
     
         6 . Membranes according to one or more of  claims 1  to  5  characterized in that they are additionally covalently cross-linked. 
     
     
         7 . Membranes according to one or more of  claims 1  to  6  characterized in that the membranes are posttreated with phosphoric acid to generate in the membrane matrix from the metal oxides and/or metal hydroxides and/or metal oxide hydroxides the metal phosphates or element phosphates or metal hydrogenphosphates or elemental hydrogenphosphates or metal dihydrogenphosphates or element dihydrogenphosphates, which contribute to proton conductivity. 
     
     
         8 . Process for the preparation of composites and composite membranes according to one or more of  claims 1  to  7  characterized in that the following components are mixed in a dipolar-aprotic solvent such as N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO) or sulfolane: a polymeric acid with SO 3 X, PO 3 X 2 , COOX or B(OX) 2  (X—H, an univalent or bivalent or trivalent or tetravalent metal cation), at least one polymeric base which carries primary, secondary or tertiary amino groups, pyridine groups, imidazole, benzimidazole, triazole, benzotriazole, pyrazole or benzopyrazole groups either in the side chain and/or the main chain and at least metalorganic or elementorganic compounds according to the compounds of  claim 4 . 
     
     
         9 . Process according to  claim 8 , characterized in that the polymer solution of  claim 7  is cast in thin films onto a support (glass-plate or metal plate, tissue, wovens, non-wovens, fleece, porous (polymer) membrane), the solvent is evaporated at temperatures of 80 to 150° C. at normal pressure or under vacuum, and the formed thin film is posttreated as follows, whereby the order of posttreatment steps can vary and also optionally the steps
 (1) and/or (2) and/or (3) can be omitted:   (1) in water at T=50 to 100° C.   (2) in 1 to 100% mineral acid (hydrokalic acid, sulfuric acid, phosphoric acid) at T=50 to 100° C.   (3) in 1 to 50% aqueous base (e.g. ammonia solution, amine solution, sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, calcium hydroxide solution, barium hydroxide solution) or in an anhydrous liquid amine or mixture of different liquid amines.   (4) in water at T=50 to 100° C.   
     
     
         10 . Use of membranes according to  claim 1  to produce energy by an electrochemical way. 
     
     
         11 . Use of membranes according to  claim 1  as component in membrane fuel cells (H 2  or direct methanol fuel cells) at temperatures from 0 to 180° C. 
     
     
         12 . Use of membranes according to  claim 1  in electrochemical cells. 
     
     
         13 . Use of membranes according to  claim 1  in secondary batteries 
     
     
         14 . Use of membranes according to  claim 1  in electrolysis cells. 
     
     
         15 . Use of membranes according to  claim 1  in membrane separation processes such as gas separation, pervaporation, perstrakation, reverse osmosis, electrodialysis and diffusion dialysis.