High temperature elastomers from linear poly (silarylene-siloxane-acetylene)

Abstract

A linear polymer has repeating units represented by the formula wherein (a) n is an integer greater than or equal to 0, (b) x is an integer greater than or equal to 1, and  represents an unconjugated acetylenic group when x is equal to 1 or conjugated acetylenic groups when x is greater than 1; (c) Ar is an aromatic group, and (c) R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof. The linear polymer may be thermally cured to form a crosslinked polymer.

1. A linear polymer comprising repeating units represented by the formula 
                 
 
       wherein
 (a) n is an integer greater than or equal to 0,  
 (b) x is an integer greater than or equal to 1, and 
                 
 
  represents an unconjugated acetylenic group when x is equal to 1 or conjugated acetylenic groups when x is greater than 1;  
 (c) Ar is an aromatic group, and  
 (c) R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof.  
 
     
     
       2. The linear polymer of  claim 1  wherein x is 2. 
     
     
       3. The linear polymer of  claim 1  wherein Ar is phenylene. 
     
     
       4. The linear polymer of  claim 1  wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are CH 3 . 
     
     
       5. The linear polymer of  claim 1  wherein n is 0. 
     
     
       6. The linear polymer of  claim 1  wherein n is 1. 
     
     
       7. The linear polymer of  claim 1  wherein n is 2. 
     
     
       8. The linear polymer of  claim 1  wherein n is 3. 
     
     
       9. A linear polymer comprising repeating units represented by the formula 
                 
 
       wherein n is an integer greater than or equal to 0, and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof. 
     
     
       10. The linear polymer of  claim 9  wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are CH 3 . 
     
     
       11. The linear polymer of  claim 9  wherein n is 0. 
     
     
       12. The linear polymer of  claim 9  wherein n is 1. 
     
     
       13. The linear polymer of  claim 9  wherein n is 2. 
     
     
       14. The linear polymer of  claim 9  wherein n is 3. 
     
     
       15. A linear polymer made by a process comprising the steps of
 (a) reacting hexachlorobutadiene with n-butyl lithium to form 1,4-dilithio-1,3-butadiyne,  
 (b) reacting the 1,4-dilithio-1,3-butadiyne of step (a) with (dimethylamino)(R 9 -disubstituted)chlorosilane, wherein each R 9  is independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof, to form 1,4-bis(dimethylamino, R 9 -disubstituted-silyl)butadiyne,  
 (c) reacting 1,4- bis(hydroxy-R 10 -disubstituted-silyl)-Ar, wherein Ar is an aromatic group, wherein R 10  is independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof, with bis(dimethylamino)R 11 -disubstituted-silane, wherein R 11  is independently selected from the group consisting of alkyl, aryl, alkylaryl, haloalkyl, haloaryl and mixtures thereof, to form a prepolymer of the formula: 
                 
 
  wherein n is an average value greater than or equal to 0, and wherein the value of n is controlled by selecting the initial molar ratio of 1,4- bis(hydroxy-R 10 -disubstituted-silyl)benzene  Ar and bis(dimethylamino)R 11 -disubstituted-silane, and  
 (d) reacting the prepolymer of step (c) with the 1,4-bis(dimethylamino, R 9 -disubstituted-silyl)butadiyne of step (b) to form the linear polymer.  
 
     
     
       16. The linear polymer of  claim 15  wherein the Ar group is phenylene. 
     
     
       17. A linear polymer made by a process comprising the steps of
 (a) reacting hexachlorobutadiene with n-butyl lithium to form 1,4-dilithio-1,3-butadiyne,  
 (b) reacting the 1,4-dilithio-1,3-butadiyne of step (a) with (dimethylamino)dimethylchlorosilane to form 1,4-bis(dimethylaminodimethylsilyl)butadiyne,  
 (c) reacting 1,4-bis(hydroxydimethylsilyl)benzene with bis(dimethylamino)dimethylsilane, to form a prepolymer of the formula: 
                 
 
  wherein n is an average value greater than or equal to 0, and wherein the value of n is controlled by selecting the initial molar ratio of 1,4-bis(hydroxydimethylsilyl)benzene and bis(dimethylamino)dimethylsilane, and  
 (d) reacting the prepolymer of step (c) with the 1,4-bis(dimethylaminodimethylsilyl)butadiyne of step (b) to form the linear polymer.