Method for making silarylene-siloxane polymers

Abstract

A method for making silarylene-siloxane polymers having the Formula: ##STR1## where R 1 -R 6 are alkyl or aryl and n is an integer above about , wherein the rate of reaction and the degree of polymerization achieved when reacting disilanols with dichlorosilanes to form silarylene-siloxane polymers are unexpectedly enhanced by a subsequent charge into the reaction medium of a tertiary amine which functions as an acid acceptor.

What is claimed is: 
     
       1. A method for making silarylene-siloxane polymers comprising the steps: (a) reacting in inert solvent a disilanol with a dichlorosilane, the disilanol having the formula: ##STR9## where R 1 , R 2 , R 3 , and R 4  are independently selected form the group consisting of alkyl and aryl radicals,   the dichlorosilane further having the formula: ##STR10## wherein R 5  and R 6  are independently selected from the group consisting of alkyl and aryl radicals;   (b) adding an effective amount of an acid acceptor;   (c) stirring for less than 1 hour; and   (d) isolating the polymer.   
     
     
       2. The method of claim 1, wherein said disilanol and said dichlorosilane are added in equivalent amounts. 
     
     
       3. The method of claim 1, wherein the reaction is maintained at from 25° C. to 50° C. by external cooling. 
     
     
       4. The method of claim 1, wherein the acid acceptor is a tertiary amine. 
     
     
       5. The method of claim 1, wherein stirring is effected for 5 minutes. 
     
     
       6. The method of claim 1, wherein the by-product residue is separated by aqueous extraction. 
     
     
       7. The method of claim 1 wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6  are methyl. 
     
     
       8. The method of claim 1, wherein R 1 , R 2 , R 3 , R 4 , and R 5  are methyl, but R 6  is phenyl. 
     
     
       9. The method of claim 1, wherein the acid acceptor is pyridine. 
     
     
       10. A method for making silarylene-siloxane polymers comprising the steps: (a) reacting in inert solvent a disilanol with a dichlorosilane, the disilanol having the formula: ##STR11## where R 1 , R 2 , R 3 , and R 4  are independently selected from the group consisting of alkyl and aryl radicals,   the dichlorosilane further having the formula: ##STR12## wherein R 5  and R 6  are independently selected from the group consisting of alkyl and aryl radicals;   (b) adding an effective amount of an acid acceptor;   (c) stirring for less than 1 hour; and   (d) isolating the polymer, whereby polymer backbone cleavage by attack form acid by-products reacting with carbon-silicon bonds, and undesirable by-product condensation is negated without the need for continually flushing inert gas through the reaction mixture to remove acid by-products and without retardation and monitoring of monomer addition and polymer formation.     
     
     
       11. Silarylene-siloxane polymers having the formula: ##STR13## where R 1  -R 6  are alkyl or aryl and n is an integer above about 50, made by the process comprising the steps: (a) reacting in inert solvent a disilanol with a dichlorosilane, the disilanol having the formula: ##STR14## where R 1 , R 2 , R 3 , and R 4  are independently selected from the group consisting of alkyl and aryl radicals,   the dichlorosilane further having the formula: ##STR15## wherein R 5  and R 6  are independently selected form the group consisting of alkyl and aryl radicals;   (b) adding an effective amount of an acid acceptor;   (c) stirring for less than 1 hour; and   (d) isolating the polymer.