US4906763A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boron nitride preceramic polymers
Assignee: ULTRASYSTEMS DEFENSE AND SPACE Inc 16775 VON KARMAN AVENUE IRVINE CALIFORNIA 92714 A CA CORP
•
Filing: 1987-11-13
•
Granted: 1990-03-06
•
Expires: 2007-11-13
Abstract
Abstract A preceramic substituted borazine polymer of the formula: ##STR1## wherein R is methyl, ethyl, propyl, or butyl, and x is a positive integer. Also disclosed are methods for making the polymer, methods for converting the polymer into coatings, shaped articles, articles including fibers and filaments formed from the polymer, blends of the foregoing polymer and preceramic triamino-N-tris (trialkylsilyl) borazines, and methods for thermally decomposing the foregoing polymers to form shaped articles of boron nitride.
Inventors
- 👤 Kazimiera J. L. Paciorek
- 👤 Reinhold H. Kratzer
- 👤 David H. Harris
- 👤 Wilfried Krone-Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:40
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/583; C01; C01B; C01B21/00; C01B21/06; C01B21/064; C04B35/622; C04B35/62227; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/10; C08; C08G; C08G79/00; C08G79/08
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
33 words
The polymer ##STR6## where R is methyl, ethyl, propyl or butyl of the general formula C n H 2n+1 and where X is a positive integer, in the form of fibers or filaments.
Claim 2
Dependent Claim
33 words
The polymer ##STR6## where R is methyl, ethyl, propyl or butyl of the general formula C n H 2n+1 and where X is a positive integer, in the form of fibers or filaments.
Claim 3
Dependent Claim
10 words
The polymer ##STR7## in the form of a shaped article.
Claim 4
Dependent Claim
10 words
The polymer ##STR7## in the form of a shaped article.
Claim 5
Dependent Claim
33 words
A shaped article formed from one or both of the following polymers ##STR8## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 6
Dependent Claim
33 words
A shaped article formed from one or both of the following polymers ##STR8## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 7
Dependent Claim
40 words
Fibers or filaments formed from a mixture of the polymer ##STR9## and one or both of the following polymers ##STR10## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 8
Dependent Claim
40 words
Fibers or filaments formed from a mixture of the polymer ##STR9## and one or both of the following polymers ##STR10## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 9
Dependent Claim
19 words
The fibers and filaments of claim 4 wherein the proportion of A polymers and B polymers are approximately equal.
Claim 10
Dependent Claim
38 words
Shaped articles formed from a mixture of the polymer ##STR11## and one or both of the polymers ##STR12## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 11
Dependent Claim
38 words
Shaped articles formed from a mixture of the polymer ##STR11## and one or both of the polymers ##STR12## wherein R is lower alkyl of the general formula C n H 2n+1 , and X is a positive integer.
Claim 12
Dependent Claim
18 words
The shaped article of claim 6 wherein A polymers and B polymers are present in approximately equal proportions.
Claim 13
Dependent Claim
91 words
The process of preparing the polymer ##STR13## comprising the steps of: (a) reacting chloroborazine with a disilazine in a mixture of organic solvents, said mixture having at least one aromatic component and at least one non-polar aliphatic component, in an atmosphere of an inert gas, and at a temperature below 0° C. but above the freezing point of said mixture for a period long enough to form a polymer solution; (b) removing precipitate from said polymer solution; and (c) then isolating the polymer by removing said solvents from said polymer solution.
Claim 14
Dependent Claim
91 words
The process of preparing the polymer ##STR13## comprising the steps of: (a) reacting chloroborazine with a disilazine in a mixture of organic solvents, said mixture having at least one aromatic component and at least one non-polar aliphatic component, in an atmosphere of an inert gas, and at a temperature below 0° C. but above the freezing point of said mixture for a period long enough to form a polymer solution; (b) removing precipitate from said polymer solution; and (c) then isolating the polymer by removing said solvents from said polymer solution.
Claim 15
Dependent Claim
22 words
The process of claim 8, wherein said atmosphere comprises a gas or a mixture of gases selected from nitrogen, helium, and argon.
Claim 16
Dependent Claim
17 words
The process of claim 9, wherein said gas or said mixture of gases is at ambient pressure.
Claim 17
Dependent Claim
41 words
The process of claim 8, wherein chloroborazine and hexamethyldisilazane are reacted in a solvent mixture comprising equal parts of benzene and hexane for a period of from about 3 to about 24 hours at temperatures from about -50° to -30° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |