Claims
- 1. A method of rendering a preceramic silazane polymer material infusible prior to pyrolysis, which method comprises treating the preceramic silazane polymer material with UV irradiation for a time sufficient to render the preceramic silazane polymer material infusible wherein the preceramic silazane polymer material contains
- (1) a vinyl- or allyl-containing preceramic silazane polymer with an average of at least 0.7 vinyl or allyl groups per molecule,
- (2) a mercapto compound with at least two SH groups per molecule, and
- (3) a photoinitiator.
- 2. A method as defined in claim 1 wherein the preceramic silazane polymer material contains a vinyl-containing preceramic silazane polymer with an average of 0.7 vinyl groups per molecule and wherein the SH/(CH.sub.2 .dbd.CH) molar ratio is greater than one half.
- 3. A method as defined in claim 1 wherein the mercapto compound contains at least three SH groups per molecule.
- 4. A method as defined in claim 2 wherein the mercapto compound contains at least three SH groups per molecule.
- 5. A method as defined in claim 2 wherein the preceramic silazane polymer material is a fiber.
- 6. A method as defined in claim 3 wherein the preceramic silazane polymer material is a fiber.
- 7. A method as defined in claim 4 wherein the preceramic silazane polymer material is a fiber.
- 8. A method as defined in claim 4 wherein the SH/(CH.sub.2 .dbd.CH) molar ratio is in the 0.6 to 1.0 range.
- 9. A method as defined in claim 4 wherein the preceramic silazane polymer material contains 5 to 15 weight percent of the mercapto compound and 0.1 to 10 weight percent of the photoinitiator based on the weight of the preceramic silazane polymer.
- 10. A method as defined in claim 9 wherein the photoinitiator is present in the range of 2.0 to 5.0 weight percent based on the weight of the preceramic silazane polymer.
- 11. A method as defined in claim 7 wherein the photoinitiator is selected from the group consisting of benzophenone, 2-hydroxy-2-methyl-1-(p-isopropylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-diethoxyacetophenone.
- 12. A method as defined in claim 8 wherein the photoinitiator is selected from the group consisting of benzophenone, 2-hydroxy-2-methyl-1-(p-isopropylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-diethoxyacetophenone.
- 13. A method as defined in claim 9 wherein the photoinitiator is selected from the group consisting of benzophenone, 2-hydroxy-2-methyl-1-(p-isopropylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-diethoxyacetophenone.
- 14. A preceramic silazane polymer composition comprising
- (1) a vinyl- or allyl-containing preceramic silazane polymer with an average of at least 0.7 vinyl or allyl groups per molecule,
- (2) a mercapto compound with at least two SH groups per molecule, and
- (3) a photoinitiator.
- 15. A composition as defined in claim 14 wherein the mercapto compound contains at least three SH groups.
- 16. A composition as defined in claim 15 wherein the mercapto compound is present in the range of 5 to 15 weight percent and wherein the photoinitiator is present in the range of 0.1 to 10 weight percent where the percentages are based on the weight of the preceramic silazane polymer.
- 17. A composition as defined in claim 16 wherein the preceramic silazane polymer is a vinyl-containing preceramic silazane polymer with an average of 0.7 vinyl groups per molecule and wherein the SH/(CH.sub.2 .dbd.CH) molar ratio is greater than one half.
- 18. A composition as defined in claim 16 wherein the SH/(CH.sub.2 .dbd.CH) molar ratio is in the 0.6 to 1.0 range.
- 19. A composition as defined in claim 14 wherein the photoinitiator is selected from the group consisting of benzophenone, 2-hydroxy-2-methyl-1-(p-isopropylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-diethoxyacetophenone.
- 20. A composition as defined in claim 17 wherein the photoinitiator is selected from the group consisting of benzophenone, 2-hydroxy-2-methyl-1-(p-isopropylphenyl)propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,2-diethoxyacetophenone.
STATEMENT OF GOVERNMENT RIGHTS
The United States Government has rights in this invention pursuant to Contract Number F33615-83-C-5006 awarded by the United States Air Force.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4537942 |
Brown-Wensley |
Aug 1985 |
|
4611035 |
Brown-Wensley |
Sep 1986 |
|
4631260 |
Bartos |
Dec 1986 |
|