End-capped polymer chains and products thereof

Abstract

Methods are described herein for converting carbocationically terminated polymers to anionically terminated polymers. These methods comprise: (a) providing a carbocationically terminated polymeric moiety; (b) reacting the carbocationically terminated polymeric moiety with a heterocyclic compound of the formula where —X— is selected from —S—, —O—, —NH— and —NR—, and where R is an alkyl group or an aryl group, thereby providing an end-capped polymeric moiety; and (c) reacting the end-capped polymeric moiety with an organolithium compound to yield an anionically terminated polymeric moiety. Also described are block copolymers in which a first polymer block comprising cationically polymerized monomers is linked to a second polymer block comprising anionically polymerized monomers by a group, as well as a polymer in which a polymer block comprising cationically polymerized monomers is linked to a halogenated silane residue or a carbosilane residue by a group.

1 . A method for converting a carbocationically terminated polymer to an anionically terminated polymer comprising: (a) providing a carbocationically terminated polymeric moiety; (b) reacting said carbocationically terminated polymeric moiety with a heterocyclic compound of the formula 
     
       
         
         
             
             
         
       
     
     where —X— is selected from —S—, —O—, —NH— and —NR—, and where R is an alkyl group or an aryl group, thereby providing an end-capped polymeric moiety, wherein at least 75 wt % of the carbocationically terminated polymeric moiety becomes attached to the heterocyclic compound in a mono-substituted fashion; and (c) reacting said end-capped polymeric moiety with an organolithium compound to yield an anionically terminated polymeric moiety. 
   
   
       2 . The method of  claim 1 , wherein —X— is —S—. 
   
   
       3 . The method of  claim 1 , wherein —X— is —O—. 
   
   
       4 . The method of  claim 1 , wherein —X— is selected from —NH— and —NR— where R is an alkyl group or an aryl group. 
   
   
       5 . The method of  claim 1 , wherein the heterocyclic compound is thiophene. 
   
   
       6 . The method of  claim 1 , wherein at least 95 wt % of the carbocationically terminated polymeric moiety becomes attached to the heterocyclic compound in a mono-substituted fashion. 
   
   
       7 . The method of  claim 1 , wherein at least 99 wt % of the carbocationically terminated polymeric moiety becomes attached to the heterocyclic compound in a mono-substituted fashion. 
   
   
       8 . The method of  claim 1 , wherein said carbocationically terminated polymeric moiety comprises a polymeric block selected from a poly(vinyl aromatic) block, a carbocationically terminated poly(vinyl ether) block, and a carbocationically terminated poly(vinyl amine) block. 
   
   
       9 . The method of  claim 1 , wherein said carbocationically terminated polymeric moiety comprises a polyolefin block. 
   
   
       10 . The method of  claim 1 , wherein said carbocationically terminated polymeric moiety comprises a polyisobutylene block. 
   
   
       11 . The method of  claim 1 , wherein said carbocationically terminated polymer comprises a plurality of carbocationically terminated moieties. 
   
   
       12 . The method of  claim 1 , wherein said organolithium compound is an alkyllithium compound. 
   
   
       13 . The method of  claim 1 , wherein said organolithium compound is selected from methyllithium, ethyllithium, isopropyllithium, normal-butyllithium, secondary-butyllithium, tertiary-butyllithium, benzyllithium and allyllithium. 
   
   
       14 . The method of  claim 1 , further comprising removing excess organolithium compound by increasing temperature of the in the presence of a reactive solvent. 
   
   
       15 . The method of  claim 1 , further comprising removing excess organolithium compound by increasing temperature increasing the temperature to 30° C. or higher in the presence of tetrahydrofuran. 
   
   
       16 . The method of  claim 1 , further comprising reacting the terminated polymeric moiety with an anionically polymerizable monomer thereby producing an anionically polymerized polymer block. 
   
   
       17 . The method of  claim 16 , wherein said anionically polymerizable monomer is selected from N,N-disubstituted acrylamide, N,N-dimethacrylamide, alkyl acrylate, alkyl methacrylate, vinyl amide, acrylonitrile, methacrylonitrile, vinyl pyridine, isopropenyl pyridines, n-alkyl isocyanate, ethylene oxide, ε-caprolactone, L,L-lactide, D,D-lactide, D,L-lactide, and their mixtures. 
   
   
       18 - 21 . (canceled)