Copolymer of ethylene oxide and at least one substituted oxirane carrying a cross-linkable function, process for preparation thereof, and use thereof for producing ionically conductive materials

Abstract

The invention concerns a copolymer of ethylene oxide and at least one substituted oxirane carrying a cross-linkable function. The copolymer comprises ethylene oxide, —O—CH 2 —CHR— units in which R is a substituent containing a reactive function which is cross-linkable by free radical process, and possibly —O—CH 2 —CHR′— units in which R′ is a substituent containing no reactive function which is cross-linkable by means of a free radical process, It is characterized by an excellent polydispersity index I=M W /Mn and a random distribution of the different monomer units. The copolymer is prepared by an anionic copolymerization process. The copolymer is useful for preparing a solid electrolyte having good mechanical properties, a good cationic conductivity and a good chemical compatibility with the electrodes of a generator operating with alkali metals such as lithium and sodium.

1 . A statistical copolymer comprising ethylene oxide, —O—CH 2 —CHR— units, in which R is a substituent having a reactive function, which is cross-linkable by free radical process, R may vary from one unit to the other and —O—CH 2 —CHR′— units in which R′ is a substituent containing no reactive function which is cross-linkable by free radical process, R′ may vary from one unit to the other, said statistical copolymer has a polydispersity index I=Mw/Mn lower than or equal to 2.2, a random distribution of monomer units and an average molecular mass in Mn number at least equal to 20,000.  
     
     
         2 . (canceled)  
     
     
         3 . The statistical copolymer according to  claim 1 , wherein the average molecular mass in Mn number is higher than or equal to 100,000.  
     
     
         4 . The statistical copolymer according to  claim 1 , wherein the substituent R is a radical having the formula CH 2 ═CH—(CH 2 ) q —(O—CH 2 ) p  in which 1≦q≦6 and p=0 or 1, or formula CH 3 —(CH 2 ) y —CH═CH—(CH 2 ) x —(OCH 2 ) p , in which 0≦x+y≦5 and p=0 or 1.  
     
     
         5 . The statistical copolymer according to  claim 1 , wherein the substituent R′ is selected among alkyl radicals; among alkoxy radicals; among alkyl(perfluoroalkyl sulfonate) ether radicals; or among radicals incorporating an ionophoric function in which the negative charge is carried by the bis(trifluoromethylsulfonyl) methylide carbanion —C(SO 2 CF 3 ) 2 M″, wherein M″ represents a metallic cation.  
     
     
         6 . The statistical copolymer according to  claim 5 , where the substituent R′ is selected among alkyl radicals having 1 to 16 carbon atoms, and a radical —(CH 2 ) n —O—((CH 2 ) m —O) p —CH 3  radicals, in which 0≦n≦4; 1≦m≦4 and 0≦p≦20.  
     
     
         7 . The statistical copolymer according to  claim 5 , wherein M″ represents a monovalent cation or a cation of an alkali metal.  
     
     
         8 . The statistical copolymer according to  claim 1 , characterized in that it contains at least 70 mole % of ethylene oxide units, about 2 to about 30 mole % of —O—CH 2 —CHR′— units and about 0.05 to about 10 mole % of —O—CH 2 —CHR— units.  
     
     
         9 - 26 . (canceled)  
     
     
         27 . The statistical copolymer according to  claim 1  comprising deactivated terminal functions.