The synthesis of multiarm poly[(r)-3-hydroxybutyrate] and its derivatives

Abstract

Provided herein is a polymer having formula I: where m, n, and R 1 are as defined herein, and the polymer has a number average molecular weight of the polymer of from 500 to 80,000 Daltons. Also provided herein are block copolymers of the polymer of formula I, as well as processes to make the polymer and block copolymers thereof.

What is claimed is: 
     
         1 - 31 . (canceled) 
     
     
         32 . A polymer having formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         m represents the repeating unit of the polymer; 
         R 1  represents a straight-chain or branched C 1-14  alkyl or a C 3-10  cycloalkyl that are substituted with n hydroxyl groups; 
         n represents 0 to 8, and wherein 
         the number average molecular weight of the polymer is from 500 to 80,000 Daltons. 
       
     
     
         33 . The polymer according to claim  1 , wherein the polymer has a number average molecular weight of from 1,000 to 10,000 Daltons. 
     
     
         34 . The polymer according to claim  1 , wherein R 1  represents a straight-chain or branched C 1-6  alkyl and n represents 0 to 5. 
     
     
         35 . The polymer according to claim  1 , wherein —R 1 (OH) n  represents hexyl or a fragment selected from formula Ia-Ic, 
       
         
           
           
               
               
           
         
         where the wavy line represents the point of attachment of the fragment —R 1 (OH) n  to the rest of the polymer. 
       
     
     
         36 . The polymer according to claim  4 , wherein:
 (a) when R 1  represents hexyl, the number average molecular weight of the polymer is from 1,000 to 7,000 Daltons;   (b) when R 1  represents the fragment of formula Ia, the number average molecular weight of the polymer is from 750 to 60,000 Daltons;   (c) when R 1  represents the fragment of formula Ib, the number average molecular weight of the polymer is from 750 to 60,000 Daltons; and   (d) when R 1  represents the fragment of formula Ic, the number average molecular weight of the polymer is from 750 to 60,000 Daltons.   
     
     
         37 . A process of preparing a polymer, which process comprises a transesterification reaction to produce a compound of formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         m represents the repeating unit of the polymer; 
         R 1  represents a straight-chain or branched C 1-14  alkyl or a C 3-10  cycloalkyl that are substituted with n hydroxyl groups; 
         n represents 0 to 8, and wherein 
         the number average molecular weight of the polymer is from 500 to 80,000 Daltons; 
         comprising reaction of a P3HB having a number average molecular weight of from 20,000 to 200,000 Daltons with an alcohol of formula II,
   R 1 OH  II
 
 
         wherein:
 R 1  represents a straight-chain or branched C 1-14  alkyl, a straight-chain or branched C 1-14  alkyl substituted with from 0 to 8 hydroxyl groups, a C 1-10  cycloalkyl or a C 1-10  cycloalkyl substituted with from 0 to 8 hydroxyl groups, and 
 the alcohol of formula II is present in a molar excess of from 100 times to 500 times (e.g. 300 times) the molar amount of the P3HB. 
 
       
     
     
         38 . The process according to claim  6 , wherein R 1  represents a straight-chain or branched C 1-6  alkyl, or a straight-chain or branched C 1-6  alkyl substituted with from 0 to 5 hydroxyl groups. 
     
     
         39 . The process according to claim  7 , wherein R 1 OH represents hexanol or a compound selected from formula Ia′-Ic′, 
       
         
           
           
               
               
           
         
       
     
     
         40 . The process according to claim  8 , wherein:
 (a) when R 1  represents hexanol, the number average molecular weight of the compound of formula I is from 1,000 to 7,000 Daltons;   (b) when R 1 OH represents the compound of formula Ia, the number average molecular weight of the compound of formula I is from 750 to 60,000 Daltons;   (c) when R 1 OH represents the compound of formula Ib, the number average molecular weight of the compound of formula I is from 750 to 60,000 Daltons; and   (d) when R 1 OH represents the compound of formula Ic, the number average molecular weight of the compound of formula I is from 750 to 60,000 Daltons.   
     
     
         41 . A process to provide a block copolymer derived from the compound of formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         m represents the repeating unit of the polymer; 
         R 1  represents a straight-chain or branched C 1-14  alkyl or a C 3-10  cycloalkyl that are substituted with n hydroxyl groups; 
         n represents 0 to 8, and wherein 
         the number average molecular weight of the polymer is from 500 to 80,000 Daltons; wherein 
         the process comprises functionalising the compound of formula I with a suitable reversible addition-fragmentation chain-transfer (RAFT) polymerization agent to form a RAFT precursor compound and reacting the RAFT precursor compound with a monomer suitable for use in RAFT polymerization to form a RAFT-polymerised block copolymer. 
       
     
     
         42 . A process to provide a block copolymer derived from the compound of formula I: 
       
         
           
           
               
               
           
         
         wherein: 
         m represents the repeating unit of the polymer; 
         R 1  represents a straight-chain or branched C 1-14  alkyl or a C 3-10  cycloalkyl that are substituted with n hydroxyl groups; 
         n represents 0 to 8, and wherein 
         the number average molecular weight of the polymer is from 500 to 80,000 Daltons; wherein 
         the process comprises reacting the compound of formula I with a suitable di- or polyisocyanate to form a polyurethane.