Patent US4777234A successfully refreshed from Google Patents.
US4777234A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicon carbide precursors
Assignee: Case Western Reserve University
•
Filing: 1986-08-25
•
Granted: 1988-10-11
•
Expires: 2006-08-25
Abstract
Abstract The present application relates to novel silicon based preceramic polymers useful in the production of silicon carbide reinforcement fibers, and to the novel synthesis procedures by which such polymers and reinforcement fibers may be produced. These novel polymers are produced by preparing phenyl substituted polyalkylcyclohexasilane compounds, which are then converted to the corresponding halogen substituted compound by reaction with the appropriate ammonium halide and sulfuric acid in a suitable solvent such as benzene, and then polymerizing the substituted cyclohexasilane by reaction with an alkali metal, again in a suitable solvent such as toluene or benzene, to produce polymers of the general formula: ##STR1## wherein R 1 is lower alkyl, preferably methyl or ethyl, R 2 is lower alkyl or hydrogen, m is 0 to 5, n is at least 3. The polymers of the present invention have an average molecular weight of from about 1000 to 100 million or more.
Inventors
- 👤 Morton H. Litt
- 👤 Kanta Kumar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:34
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C08; C08G; C08G77/00; C08G77/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
62 words
A polyalkylcyclohexasilane preceramic polymer having a molecular weight of at least 1000 and having the general formula: ##STR8## wherein R 1 is lower alkyl, R 2 is hydrogen or a lower alkyl radial, m is 0 to 5, and n is at least 3 and wherein the linkages between monomer units are the same or different and is 1,2-, 1,3- or 1,4-.
Claim 2
Dependent Claim
62 words
A polyalkylcyclohexasilane preceramic polymer having a molecular weight of at least 1000 and having the general formula: ##STR8## wherein R 1 is lower alkyl, R 2 is hydrogen or a lower alkyl radial, m is 0 to 5, and n is at least 3 and wherein the linkages between monomer units are the same or different and is 1,2-, 1,3- or 1,4-.
Claim 3
Dependent Claim
13 words
The polymer of claim 1 wherein said polymer corresponds to the formula: ##STR9##
Claim 4
Dependent Claim
13 words
The polymer of claim 1 wherein said polymer corresponds to the formula: ##STR10##
Claim 5
Independent Claim
99 words
The method of preparing a silicon based preceramic polymer, the steps which comprise converting a phenyl substituted polyalkylcyclohexasilane to the corresponding halogen substituted cyclohexasilane analogue by reaction with an ammonium halide and sulfuric acid in a solvent and then polymerizing said halogen substituted cyclohexasilane by reaction with an alkali metal, to produce a polymer of the general formula: ##STR11## wherein R 1 is lower alkyl and R 2 is hydrogen or a lower alkyl, m is 0 to 5 and n is at least 3, and said polymers have an average molecular weight of from about 1000 to 100,000,000.
Claim 6
Independent Claim
99 words
The method of preparing a silicon based preceramic polymer, the steps which comprise converting a phenyl substituted polyalkylcyclohexasilane to the corresponding halogen substituted cyclohexasilane analogue by reaction with an ammonium halide and sulfuric acid in a solvent and then polymerizing said halogen substituted cyclohexasilane by reaction with an alkali metal, to produce a polymer of the general formula: ##STR11## wherein R 1 is lower alkyl and R 2 is hydrogen or a lower alkyl, m is 0 to 5 and n is at least 3, and said polymers have an average molecular weight of from about 1000 to 100,000,000.
Claim 7
Dependent Claim
13 words
The method of claim 4 wherein said polymer corresponds to the formula: ##STR12##
Claim 8
Dependent Claim
13 words
The method of claim 4 wherein said polymer corresponds to the formula: ##STR13##
Claim 9
Independent Claim
113 words
The method of preparing a silicon carbide reinforcement, the steps which comprise: converting a phenyl substituted polyalkylcyclohexasilane to the corresponding halogen substituted cyclohexasilane analogue by reaction with an ammonium halide and sulfuric acid in a solvent and then polymerizing said halogen substituted cyclohexasilane by reaction with an alkali metal, to produce a polymer of the general formula: ##STR14## wherein R 1 is lower alkyl, R 2 is hydrogen or a lower alkyl, m is 0 to 5, and n is at least 3, and said polymers have an average molecular weight of from about 1000 to 100,000,000; forming said polymer into the desired reinforcing configuration, and pyrolyzing said formed polymer to silicon carbide.
Claim 10
Independent Claim
113 words
The method of preparing a silicon carbide reinforcement, the steps which comprise: converting a phenyl substituted polyalkylcyclohexasilane to the corresponding halogen substituted cyclohexasilane analogue by reaction with an ammonium halide and sulfuric acid in a solvent and then polymerizing said halogen substituted cyclohexasilane by reaction with an alkali metal, to produce a polymer of the general formula: ##STR14## wherein R 1 is lower alkyl, R 2 is hydrogen or a lower alkyl, m is 0 to 5, and n is at least 3, and said polymers have an average molecular weight of from about 1000 to 100,000,000; forming said polymer into the desired reinforcing configuration, and pyrolyzing said formed polymer to silicon carbide.
Claim 11
Dependent Claim
13 words
The method of claim 7 wherein said polymer corresponds to the formula: ##STR15##
Claim 12
Dependent Claim
13 words
The method of claim 7 wherein said polymer corresponds to the formula: ##STR16##
References Cited (Backward Citations)
US4590253A
Cited
US4537942A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-11 | 1992-04-11 | 1992-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-11 | 1996-04-11 | 1996-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-11 | 2000-04-11 | 2000-10-11 | $7700.00 | Window Closed / Lapsed |