Phenylmethylpolysilane polymers and process for their preparation

• US 4,260,780 A
• Filed: 11/27/1979
• Issued: 04/07/1981
• Est. Priority Date: 11/27/1979
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: West, Robert C.
• Primary Examiner(s): Shaver, Paul F.
• Application Number:
  US06/097,778
• Time in Patent Office: 497 Days
• Field of Search: 260/448.2 D, 556/430
• US Class Current: 556/430
• CPC Class Codes: C04B 35/571 obtained from Si-containing polymer precursors or organosilicon monomers
• CPC Class Codes: C07F 7/0803 Compounds with Si-C or Si-Si linkages
• CPC Class Codes: C08G 77/60 in which all the silicon atoms are connected by linkages other than oxygen atoms

Abstract

A phenylmethylpolysilane polymer is prepared by the addition of a small amount of phenylmethyldichlorosilane to dimethyldichlorosilane and reduction of the resulting mixture. The polymer is a gum or meltable resinous material which has utility as a precursor for preparing silicon carbide fibers.

Claims

1. A phenylmethylpolysilane polymer having the following structural formula:

##STR2## wherein Me is methyl, Ph is phenyl, the ratio of x to y varies from about 1;

3 to 1;

20, and z is an integer ranging from about 1 to 100.

2. A process for preparing a phenylmethylpolysilane polymer which comprises the steps of (a) mixing phenylmethyl dichlorosilane and dimethyldichlorosilane in which the mole ratio of phenylmethyldichlorosilane to dimethyldichlorosilane ranges from about 1:

3 to 1;

20;

(b) adding the resulting mixture to a solvent containing an alkali metal reducing agent;

(c) refluxing the resulting solution thereby causing a coupling reaction to occur; and

(d) recovering a solid polymer from the said resulting solution.

3. A process in accordance with claim 2 in which the mole ratio of phenylmethyldichlorosilane to dimethyldichlorosilane is 1:

3.9.

4. The process according to claim 2 in which the alkali metal reducing agent is sodium, potassium or a sodium-potassium alloy.

5. The process according to claim 4 in which the solvent is xylene or tetrahydrofuran.

6. The process according to claim 5 in which the solution is refluxed for at least about 24 hours.

7. The process according to claim 6 in which the solution is refluxed for a period of about 24 to 48 hours.

8. The process according to claim 5 in which the reaction is quenched at the end of the reflux period, thereby causing polymer to precipitate from solution;

the polymer is separated from the solution; and

the separated polymer is dried.

9. The process according to claim 8 in which the reaction is quenched first with methanol and then with an equal volume of 1 M hydrochloric acid and ethanol.

10. The process according to claim 8 in which the reaction is quenched first with hexane and then with water.