US5051215A
Expired / Lapsed
US
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Curing preceramic polymers by exposure to nitrogen dioxide
Assignee: Dow Silicones Corp
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Filing: 1990-03-21
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Granted: 1991-09-24
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Expires: 2010-03-21
Abstract
Abstract A rapid method of infusibilizing (curing) preceramic polymers comprising treatment said polymers with gaseous nitrogen dioxide. The infusibilized polymers may be pyrolyzed to temperatures in excess of about 800° C. to yield ceramic materials with low oxygen content and, thus, good thermal stability. The methods are especially useful for the production of ceramic fibers and, more specifically, to the on-line production of ceramic fibers.
Inventors
- 👤 James A. Rabe
- 👤 Jonathan Lipowitz
- 👤 Paul P. Lu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:44
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C04B35/58; C04B35/584; C04B35/589; C04B35/622; C04B35/62227; C04B35/62272; C04B35/62277; C04B35/62281; C04B35/62286; C04B35/62295; C08; C08G; C08G77/00; C08G77/60
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
54 words
A method of infusibilizing a preceramic polymer selected from the group consisting of polycarbosilanes, polysilanes and polysilazanes comprising treating the preceramic polymer with gaseous nitrogen dioxide at a temperature in the range of from about room temperature up to about 300° C. for less than about 2 hours to render the preceramic polymer infusible.
Claim 2
Independent Claim
54 words
A method of infusibilizing a preceramic polymer selected from the group consisting of polycarbosilanes, polysilanes and polysilazanes comprising treating the preceramic polymer with gaseous nitrogen dioxide at a temperature in the range of from about room temperature up to about 300° C. for less than about 2 hours to render the preceramic polymer infusible.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein the infusibilized preceramic polymer pyrolyzes to a ceramic which contains less than about 10 weight percent oxygen.
Claim 4
Dependent Claim
23 words
The method of claim 2 wherein the infusibilized preceramic polymer pyrolyzes to a ceramic which contains less than about 7 weight percent oxygen.
Claim 5
Dependent Claim
16 words
The method of claim 2 wherein the preceramic polymer is in the form of a fiber.
Claim 6
Dependent Claim
26 words
The method of claim 2 wherein the nitrogen dioxide is present in a concentration of about 0.5 to 25 weight percent diluted in an inert gas.
Claim 7
Dependent Claim
26 words
The method of claim 4 wherein the nitrogen dioxide is present in a concentration of about 0.5 to 25 weight percent diluted in a inert gas.
Claim 8
Dependent Claim
26 words
The method of claim 2 wherein the nitrogen dioxide is present in a concentration of about 2 to 10 weight percent diluted in an inert gas.
Claim 9
Dependent Claim
21 words
The method of claim 2 wherein the time sufficient to render the preceramic polymer infusible is less than about 30 minutes.
Claim 10
Dependent Claim
12 words
The method of claim 5 wherein the preceramic polymer is a polycarbosilane.
Claim 11
Dependent Claim
12 words
The method of claim 5 wherein the preceramic polymer is a methylpolysilane.
Claim 12
Dependent Claim
12 words
The method of claim 5 wherein the preceramic polymer is a polysilazane.
Claim 13
Dependent Claim
11 words
The method of claim 5 wherein the preceramic polymer is hydridopolysilazane.
Claim 14
Independent Claim
69 words
A method of infusibilizing a preceramic fiber selected from the group consisting of polycarbosilanes, polysilanes and polysilazanes on a continuous spinning line comprising treating said preceramic fiber with gaseous nitrogen dioxide at a temperature in the range of from about room temperature up to about 300° C. for less than about 2 hours to render said preceramic polymer infusible as the fiber is continuously processed from spinning through pyrolysis.
Claim 15
Independent Claim
69 words
A method of infusibilizing a preceramic fiber selected from the group consisting of polycarbosilanes, polysilanes and polysilazanes on a continuous spinning line comprising treating said preceramic fiber with gaseous nitrogen dioxide at a temperature in the range of from about room temperature up to about 300° C. for less than about 2 hours to render said preceramic polymer infusible as the fiber is continuously processed from spinning through pyrolysis.
Claim 16
Dependent Claim
23 words
The method of claim 13 wherein the infusibilized preceramic fiber pyrolyzes to a ceramic which contains less than about 10 weight percent oxygen.
Claim 17
Dependent Claim
23 words
The method of claim 14 wherein the polymer is treated at a temperature in the range of about 50° to about 300° C.
Claim 18
Dependent Claim
21 words
The method of claim 15 wherein the time sufficient to render the preceramic fiber infusible is less than about 10 seconds.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-23 | 1995-03-25 | 1995-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-23 | 1999-03-25 | 1999-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-23 | 2003-03-25 | 2003-09-24 | $7700.00 | Window Closed / Lapsed |