Novel Polyisobutylene-Based Thermoplastic Elastomers

Abstract

The present invention is directed to a new class of thermoplastic elastomers (TPEs) and processes for making them. In some embodiments of the present invention, the end groups of the multi-arm PIB copolymer is a conjugated diene, whereas the other component is a multi-functional dienophile. The components of the TPE of the present invention are chemically connected via the well-known Diels-Alder reaction which is thermally reversible (by the retro-Diels-Alder reaction) at moderately elevated temperatures. The reversibility of the Diels-Alder retro-Diels-Alder reactions allows the recovery of the original components of the TPE and thus its recyclability and also gives the TPE the ability to be reshaped or reformed.

1 . A 3-(2-methoxyispropyl)styrene composition having the formula (i): 
       
         
           
           
               
               
           
         
       
     
     
         2 . A method for synthesizing the 3-(2-methoxyispropyl)styrene composition of  claim 1  comprising:
 a) reacting a 3-bromostyrene with magnesium to form a compound having the structure of formula (ii); 
 
       
         
           
           
               
               
           
         
         b) reacting the compound of formula (ii) with acetone to form a compound having the structure of formula (iii); 
       
       
         
           
           
               
               
           
         
         c) reacting the compound of formula (iii) with H 2 O to form a compound having the structure of formula (iv); and 
       
       
         
           
           
               
               
           
         
         d) reacting the compound of formula (iv) with CH 3 I to form 3-(2-methoxyispropyl)styrene. 
       
     
     
         3 . A multi-arm polyisobutylene (PIB) polymer comprising:
 a) an oligomeric styrene pre-polymer having a sec-butyl head group, a poly(-methylstyrene) segment from about 3 to about 5 units in length and a poly[3-(2-methoxyisopropyl)styrene] segment from about 3 units to about 50 units in length and having the structure of formula (v):   
       
         
           
           
               
               
           
         
         wherein n is an integer from 3 to 5 and m is an integer from 3 to 50; and 
         b) at least one PIB arm extending from each 3-(2-methoxyisopropyl)styrene 
         wherein said PIB arms are terminated with end groups selected from the group consisting of allyls, dienes, and furans. 
       
     
     
         4 . The multi-arm PIB polymer of  claim 3  wherein said end groups are allyl end groups. 
     
     
         5 . The multi-arm PIB polymer  claim 4  having the formula (vi): 
       
         
           
           
               
               
           
         
         wherein n is an integer from about 3 to about 5, m is an integer from about 3 to about 50, and q is an integer from about 10 to about 10,000. 
       
     
     
         6 . The multi-arm PIB polymer of  claim 3  wherein said end groups are diene end groups. 
     
     
         7 . The multi-arm PIB polymer of  claim 3  wherein said end groups are furan end groups. 
     
     
         8 . The multi-arm PIB polymer of  claim 7  having the formula (vii): 
       
         
           
           
               
               
           
         
         wherein n is an integer from about 2 to about 5, m is an integer from about 3 to about 50, and q is an integer from about 10 to about 10,000. 
       
     
     
         9 . (canceled) 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . A method for synthesizing a multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and allyl end groups comprising:
 a) reacting a sec-butyl lithium and an-methylstyrene to form an-methylstyrene oligomer of from about 3 units to about 5 units in length, said-methylstyrene oligomer having a sec-butyl head group and a lithium ion;   b) reacting the-methylstyrene oligomer of step (a) with potassium tert-butoxide to replace the lithium ion on the-methylstyrene oligomer with a potassium ion;   c) reacting the-methylstyrene oligomer of step (b) with a 3-(2-methoxyisopropyl)styrene to form an oligomeric styrene pre-polymer having a sec-butyl head group, a poly(-methylstyrene) segment of from about 3 to about 5 units in length, and a poly [3-(2-methoxyisopropyestyrene] segment of from about 3 to about 50 units in length;   d) combining the oligomeric styrene pre-polymer of step (c), a stoichiometric excess of isobutylene, and a photoinitiator, wherein said isobutylene is added to at least one of the 3-(2-methoxyisopropyl)styrene units of said poly[3-(2-methoxyisopropyestyrene] segment of said oligomeric styrene pre-polymer by cationic polymerization to create PIB arms of from 10 units to 10,000 units in length extending from each of said 3-(2-methoxyisopropyl)styrene units; and   e) adding allyltrimethylsilane to terminate the isobutylene polymerization and place an allyl end group on the end of said PIB arms.   
     
     
         13 . (canceled) 
     
     
         14 . A method for synthesizing a multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and diene end groups comprising:
 a) dissolving the allyl-terminated multi-arm polyisobutylene of  claim 5  and a photoinitiator in a solvent to provide a solution;   b) adding furfuryl mercaptan to provide a solution comprising furfuryl mercaptan and the solution of step (a);   c) irradiating the solution of step (b); and   d) removing the solvent to provide a multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and diene end groups.   
     
     
         15 . The method of  claim 14  further comprising the steps of:
 e) redissolving the multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and a diene end groups of step (d) in hexane; 
 f) washing the solution of step (e) with methanol; and 
 g) removing said hexane and said methanol under reduced pressure to leave the multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and a diene end groups. 
 
     
     
         16 . The method of  claim 14  wherein the photoinitiator is 2,2-dimethoxy-2-phenyl acetophenone and the solvent is dichloromethane. 
     
     
         17 . A thermoplastic elastomer network comprising:
 a) a plurality of the multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and a diene end groups of  claim 12 ; and   b) a plurality of multi-functional dienophiles,   wherein said multi-functional dienophiles are chemically bonded to one or more of said diene end groups to form a thermoplastic elastomer network.   
     
     
         18 . The thermoplastic elastomer network of  claim 17  having the formula (viii): 
       
         
           
           
               
               
           
         
         wherein n is an integer from about 3 to about 5, m is an integer from about 3 to about 50, 
         q is an integer from about 10 to about 10,000 and R can be either an aliphatic or aromatic group. 
       
     
     
         19 . The thermoplastic elastomer network of  claim 17 , wherein said diene end group is a furan end group. 
     
     
         20 . The thermoplastic elastomer network of  claim 17 , wherein said multi-functional dienophiles are selected from the group consisting of aliphatic/aromatic bis-maleimide, tris-maleimide, and combinations thereof. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . A method for making a thermoplastic elastomer network comprising reacting the multi-arm polyisobutylene having an oligomeric styrene, a sec-butyl head group, and a diene end groups of  claim 14  and a plurality of multi-functional dienophiles to form a reversibly crosslinked thermoplastic elastomer. 
     
     
         28 . The method of  claim 27 , wherein said diene end groups are a furan end groups. 
     
     
         29 . The method of  claim 27 , wherein said multi-functional dienophiles are selected from the group consisting of aliphatic/aromatic bis-maleimide, tris-maleimide, and combinations thereof. 
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . A method for making a thermoplastic elastomer network comprising reacting: the multi-arm polyisobutylene of  claim 12  having an oligomeric styrene, a sec-butyl head group, and diene end groups; a plurality of multi-functional dienophiles; and a plurality of tris-furan molecules to form a reversibly crosslinked thermoplastic elastomer.