US4767876A
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Method for converting organosilicon polymers containing SIH repeat units and organopolysilazane precursors to new and useful preceramic polymers and silicon nitride enriched ceramic materials
Assignee: Massachusetts Institute of Technology
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Filing: 1986-10-07
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Granted: 1988-08-30
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Expires: 2006-10-07
Abstract
Abstract A method of forming preceramic polymers using an organosilicon polymer containing Si--H repeat units by reacting it with alkali metal amide or silylamide is disclosed. Preferably, the silylamide is a polymeric silylamide formed by reacting in solution anhydrous ammonia with a mixture of R 1 SiHX 2 (where R 1 is a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms; and X is a halogen) and R 2 SiX 3 (where R 2 is H, a lower alkenyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms). The Si--H containing organosilicon polymer is preferably selected from the group consisting of organopolysilanes of the formula [(RSiH) x (RSi) y ] n (where R is a lower alkyl group having from 1 to about 6 carbon atoms, a lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and n is greater than 1), a polycarbosilane having repeat units of the formula [R a Si(H)--(CH 2 ) q ] (where R a is H, a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having from 3 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, q is an integer 1 or greater), and a polysiloxane having repeat units of the formula [R b Si(H)O] n (where R b is a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having from 3 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and n is an integer greater than 1). Novel preceramic polymers formed by this method are also disclosed.
Inventors
- 👤 Dietmar Seyferth
- 👤 Joanne M. Schwark
- 👤 Yuan-Fu Yu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:34
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/60; C04; C04B; C04B35/00; C04B35/515; C04B35/56; C04B35/565; C04B35/571; C04B35/622; C04B35/62227; C04B35/62272; C04B35/62277; C04B35/62281; C08L; C08L83/00; C08L83/16; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6562; C04B2235/658; C04B2235/6586
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
68 words
A method for preparing preceramic organosilicon polymers, wherein the method comprises: (a) mixing an organosilicon polymer containing Si--H repeat units with at least a catalytic amount of an alkali metal amide or a silylamide in an organic solvent; (b) allowing the mixture of step (a) to react at room temperature or above; and (c) quenching the reaction mixture with a reactive electrophile, thereby forming said preceramic organosilicon polymer.
Claim 2
Independent Claim
68 words
A method for preparing preceramic organosilicon polymers, wherein the method comprises: (a) mixing an organosilicon polymer containing Si--H repeat units with at least a catalytic amount of an alkali metal amide or a silylamide in an organic solvent; (b) allowing the mixture of step (a) to react at room temperature or above; and (c) quenching the reaction mixture with a reactive electrophile, thereby forming said preceramic organosilicon polymer.
Claim 3
Dependent Claim
192 words
The method of claim 1, wherein the silylamide is a polymeric silylamide formed by reacting in solution anhydrous ammonia with a mixture of R 1 SiHX 2 , wherein R 1 is a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and X is a halogen, and R 2 SiX 3 , wherein R 2 is H, a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, or a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, thereby forming a polysilazane; and reacting said polysilazane in the presence of a basic catalyst capable of deprotonating the NH functions in said polysilazane to form said polymeric silylamide.
Claim 4
Dependent Claim
212 words
The method of claim 2 wherein the Si--H containing organosilicon polymer is selected from the group consisting of an organopolysilane of the formula [(RSiH) x (RSi) y ] n , where x+y=1,R is a lower alkyl group having from 1 to about 6 carbon atoms, a lower alkenyl group having 2 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbons atoms, and n is an integer greater than 1; a polycarbosilane having a plurality of repeat units of the formula [R a Si(H)--(CH 2 ) q ] where R a is H, a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having 3 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and q is an integer 1 or greater; and a polysiloxane having a plurality of repeat units of the formula R b Si(H)O] n where R b is a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having 3 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and n is an integer greater than 1.
Claim 5
Dependent Claim
48 words
The method of claim 3 wherein the polycarbosilane contains at least about 25 mole % of repeat units of the formula [R a Si(H)--(CH 2 ) q ]and the polysiloxane contains at least about 25 mole % of repeat units of the formula [R b Si(H)O] n .
Claim 6
Dependent Claim
17 words
The method of claim 3, wherein R, R a and R b are a lower alkyl group.
Claim 7
Dependent Claim
16 words
The method of claim 3, wherein R, R a and R b are CH 3 .
Claim 8
Dependent Claim
18 words
The method of claim 3, wherein the Si--H containing the organosilicon polymer is an organopolysilane and x=1, y=0.
Claim 9
Dependent Claim
46 words
The method of claim 3 wherein the reaction mixture is quenched with an electrophile, E--X 1 , where E is selected from the group consisting of lower alkyl groups and silyl groups and X 1 is selected from the group consisting of halogen, sulfate and sulfonate.
Claim 10
Dependent Claim
60 words
The method of claim 3 wherein the Si--H containing organosilicon polymer is organopolysilane, and the polymeric silylamide is added in a sufficient quantity so that the excess carbon obtained on pyrolysis of the silylamide can react with excess silicon from the pyrolysis of the organopolysilane compound, thus producing a ceramic product which contains substantially no free silicon or free carbon.
Claim 11
Dependent Claim
22 words
The method of claim 3 wherein R 1 is a lower alkyl group, R 2 is H or a lower alkyl group.
Claim 12
Dependent Claim
12 words
The method of claim 10 wherein R 1 is CH 3 .
Claim 13
Dependent Claim
13 words
The method of claim 11 wherein R 2 is CH 3 or H.
Claim 14
Dependent Claim
13 words
The method of claim 10 wherein R 2 is CH 3 or H.
Claim 15
Dependent Claim
16 words
The method of claim 10 wherein R, R a and R b are CH 3 .
Claim 16
Dependent Claim
21 words
The method of claim 9 wherein the mixture is allowed to react by stirring at room temperature, then heating at reflux.
Claim 17
Dependent Claim
21 words
The method of claim 9 wherein the mole ratio of organopolysilane to polymeric silylamide ranges from about 4:1 to about 1:4.
Claim 18
Dependent Claim
10 words
A preceramic polymer formed by the method of claim 3.
Claim 19
Dependent Claim
15 words
The method of claim 1 wherein the alkali metal amide is an alkali metal silylamide.
Claim 20
Dependent Claim
15 words
The method of claim 3 wherein the Si--H containing organosilicon polymer is a poly(phenyl)silicon polymer.
Claim 21
Dependent Claim
25 words
The method of claim 3 wherein the Si--H containing organosilicon polymer is a polycarbosilane and the weight ratio of polycarbosilane:silylamide is about 10:1 or less.
Claim 22
Dependent Claim
60 words
The method of claim 3 wherein the Si--H containing organosilicon polymer is a mixture of the polycarbosilane and the organopolysilane, with a sufficient quantity of the organopolysilane added so that the excess silicon obtained on pyrolysis of the organopolysilane can react with excess carbon from the pyrolysis of the polycarbosilane and the silylamide. thereby reducing the amount of free carbon.
Claim 23
Dependent Claim
10 words
A preceramic polymer produced by the method of claim 21.
Claim 24
Dependent Claim
26 words
The method of claim 3 wherein the Si--H containing organosilicon polymer is a polysiloxane and the weight ratio of polysiloxane:silylamide is from about 15:1 to 1:15.
Claim 25
Dependent Claim
28 words
The method claim 3, wherein the Si--H containing organosilicon polymer is a polysiloxane and the weight ratio of polysiloxane to alkali metal silylamide is about 5:1 to 1:5.
Claim 26
Dependent Claim
11 words
The method of claim 24 wherein the ratio is about 1:1.
Claim 27
Dependent Claim
10 words
A preceramic polymer formed by the method of claim 25.
Claim 28
Independent Claim
245 words
A method for preparing a preceramic organosilicon polymer, wherein the method comprises: (a) generating a polysilylamide in the presence of an Si--H containing organosilicon polymer wherein the polysilylamide is generated by reacting the coammonolysis product of a mixture of R 1 SiHX 2 , where R 1 is a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, a substituted or unsubstituted, lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms; and X is a halogen; with R 2 SiX 3 wherein R 2 is H, a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, or a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms in the presence of a basic catalyst capable of deprotonating the hydrogen from a nitrogen atom adjacent to a silicon atom to generate the polysilylamide in situ; (b) allowing the in situ generated polysilylamide and the Si--H containing organosilicon polymer sufficient time to react with each other at room temperature; and (c) quenching the mixture with an organic halide or halosilane to produce the organosilicon preceramic polymer.
Claim 29
Independent Claim
245 words
A method for preparing a preceramic organosilicon polymer, wherein the method comprises: (a) generating a polysilylamide in the presence of an Si--H containing organosilicon polymer wherein the polysilylamide is generated by reacting the coammonolysis product of a mixture of R 1 SiHX 2 , where R 1 is a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, a substituted or unsubstituted, lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms; and X is a halogen; with R 2 SiX 3 wherein R 2 is H, a lower alkyl group having from 1 to about 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 3 to about 6 carbon atoms, or a substituted or unsubstituted lower alkenyl group having from 2 to about 6 carbon atoms, or a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms in the presence of a basic catalyst capable of deprotonating the hydrogen from a nitrogen atom adjacent to a silicon atom to generate the polysilylamide in situ; (b) allowing the in situ generated polysilylamide and the Si--H containing organosilicon polymer sufficient time to react with each other at room temperature; and (c) quenching the mixture with an organic halide or halosilane to produce the organosilicon preceramic polymer.
Claim 30
Dependent Claim
212 words
The method of claim 27 wherein the Si--H containing organosilicon polymer is selected from the group consisting of an organopolysilane of the formula [(RSiH) x (RSi) y ] n , where x+y=1, R is a lower alkyl group having from 1 to about 6 carbon atoms, a lower alkenyl group having 2 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbons atoms, and n is an integer greater than 1; a polycarbosilane having a plurality of repeat units of the formula [R a Si(H)--(CH 2 ) q ] where R a is H, a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having 3 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and q is an integer 1 or greater; and a polysiloxane having a plurality of repeat units of the formula[R b Si(H)O] n where R b is a lower alkyl group having from 1 to about 6 carbon atoms, a cycloalkyl group having 3 to about 6 carbon atoms, a substituted or unsubstituted lower aryl group having from 6 to about 10 carbon atoms, and n is an integer 1 or greater.
Claim 31
Dependent Claim
49 words
The method of claim 28 wherein the polycarbosilane contains at least about 25 mole % of repeat units of the formula [R a Si(H)--(CH 2 ) q ] and the polysiloxane contains at least about 25 mole % of repeat units of the formula [R b Si(H)O] n .
Claim 32
Dependent Claim
17 words
The method of claim 28, wherein R, R a and R b are a lower alkyl group.
Claim 33
Dependent Claim
16 words
The method of claim 28, wherein R, R a and R b are CH 3 .
Claim 34
Dependent Claim
23 words
The method of claim 28 wherein R 1 is a lower alkyl group and R 2 is H or a lower alkyl group.
Claim 35
Dependent Claim
12 words
The method of claim 32 wherein R 1 is CH 3 .
Claim 36
Dependent Claim
14 words
The method of claim 33 wherein R 2 is H or CH 3 .
Claim 37
Dependent Claim
10 words
The method of claim 34 wherein R 2 is H.
Claim 38
Dependent Claim
19 words
The method claim 31 wherein R 1 is CH 3 and R 2 is H or CH 3 .
Claim 39
Dependent Claim
17 words
The method of claim 28, wherein the Si--H containing organosilicon polymer is an organopolysilane and x=1, y=0.
Claim 40
Dependent Claim
59 words
The method of claim 28 wherein the Si--H containing organosilicon polymer is organopolysilane, and the organopolysilane is added in a sufficient quantity so that the excess carbon obtained on pyrolysis of the silylamide can react with excess silicon from the pyrolysis of the organopolysilane compound, thus producing a ceramic product which contains substantially no free silicon or free carbon.
Claim 41
Dependent Claim
21 words
The method of claim 28 wherein the mixture is allowed to react by stirring at room temperature, then heating at reflux.
Claim 42
Dependent Claim
23 words
The method of claim 28 wherein the mole ratio of organopolysilane to in situ generated silylamide ranges from about 4:1 to about 1:4.
Claim 43
Dependent Claim
63 words
The method of claim 28 wherein the Si--H containing organosilicon polymer is a mixture of the polycarbosilane and the organopolysilane, with a sufficient quantity of the organopolysilane added so that the excess silicon obtained on pyrolysis of the organopolysilane can react with excess carbon from the pyrolysis of the polycarbosilane and the in situ generated silylamide, thereby reducing the amount of free carbon.
Claim 44
Dependent Claim
30 words
The method of claim 28 wherein the Si--H containing organosilicon polymer is a polysiloxane and the weight ratio of polysiloxane: in situ generated silylamide is from about 15:1 to 1:15.
Claim 45
Dependent Claim
11 words
The method of claim 42 wherein the ratio is about 1:1.
Claim 46
Dependent Claim
10 words
A preceramic polymer formed by the method of claim 28.
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