CA1338969C - Preceramic metallopolysilanes - Google Patents
Preceramic metallopolysilanesInfo
- Publication number
- CA1338969C CA1338969C CA000613367A CA613367A CA1338969C CA 1338969 C CA1338969 C CA 1338969C CA 000613367 A CA000613367 A CA 000613367A CA 613367 A CA613367 A CA 613367A CA 1338969 C CA1338969 C CA 1338969C
- Authority
- CA
- Canada
- Prior art keywords
- metallic compound
- polysilane
- coordination sites
- open coordination
- tungsten
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229920000548 poly(silane) polymer Polymers 0.000 claims abstract description 69
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 44
- 238000000034 method Methods 0.000 claims abstract description 38
- 229910000765 intermetallic Inorganic materials 0.000 claims abstract description 37
- 229910052751 metal Inorganic materials 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 32
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 31
- 239000010937 tungsten Substances 0.000 claims abstract description 31
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 23
- 239000011733 molybdenum Substances 0.000 claims abstract description 23
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims abstract description 21
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 12
- 239000011651 chromium Substances 0.000 claims abstract description 12
- 239000010936 titanium Substances 0.000 claims abstract description 12
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 11
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000003446 ligand Substances 0.000 claims abstract description 11
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 9
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 9
- 229910052796 boron Inorganic materials 0.000 claims abstract description 9
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims abstract description 8
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 claims abstract description 8
- 229910052735 hafnium Inorganic materials 0.000 claims abstract description 8
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 8
- 239000010955 niobium Substances 0.000 claims abstract description 8
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 8
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 8
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 4
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 claims abstract 3
- 239000012298 atmosphere Substances 0.000 claims description 10
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 9
- 229910021529 ammonia Inorganic materials 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 abstract description 16
- 238000002360 preparation method Methods 0.000 abstract description 10
- 150000002739 metals Chemical class 0.000 abstract description 5
- 230000008569 process Effects 0.000 abstract description 4
- 230000009467 reduction Effects 0.000 abstract description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 45
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 27
- 239000001301 oxygen Substances 0.000 description 27
- 229910052760 oxygen Inorganic materials 0.000 description 27
- 229920000642 polymer Polymers 0.000 description 26
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 23
- 229910052710 silicon Inorganic materials 0.000 description 22
- 239000010703 silicon Substances 0.000 description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 20
- 229910052799 carbon Inorganic materials 0.000 description 19
- 239000001257 hydrogen Substances 0.000 description 17
- 229910052739 hydrogen Inorganic materials 0.000 description 17
- 230000014759 maintenance of location Effects 0.000 description 14
- 238000000197 pyrolysis Methods 0.000 description 14
- 239000000523 sample Substances 0.000 description 13
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical group [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 12
- 239000000919 ceramic Substances 0.000 description 12
- 239000000460 chlorine Substances 0.000 description 12
- 229910052801 chlorine Inorganic materials 0.000 description 12
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 10
- 150000002431 hydrogen Chemical group 0.000 description 10
- 238000002329 infrared spectrum Methods 0.000 description 10
- 239000012300 argon atmosphere Substances 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 9
- 229910052736 halogen Inorganic materials 0.000 description 8
- 150000002367 halogens Chemical class 0.000 description 8
- 230000001590 oxidative effect Effects 0.000 description 8
- 229910010271 silicon carbide Inorganic materials 0.000 description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 7
- 238000002441 X-ray diffraction Methods 0.000 description 7
- 238000005227 gel permeation chromatography Methods 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 6
- 125000003277 amino group Chemical group 0.000 description 6
- 229910052786 argon Inorganic materials 0.000 description 6
- 230000009477 glass transition Effects 0.000 description 6
- 125000005843 halogen group Chemical group 0.000 description 6
- 239000011541 reaction mixture Substances 0.000 description 6
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 5
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 5
- 229910021431 alpha silicon carbide Inorganic materials 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 238000004821 distillation Methods 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 4
- 125000000217 alkyl group Chemical group 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- -1 aryl Grignard reagents Chemical class 0.000 description 4
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 4
- 229910000077 silane Inorganic materials 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- 150000003657 tungsten Chemical class 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910008045 Si-Si Inorganic materials 0.000 description 3
- 229910006411 Si—Si Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910008814 WSi2 Inorganic materials 0.000 description 3
- 125000001309 chloro group Chemical group Cl* 0.000 description 3
- KQHIGRPLCKIXNJ-UHFFFAOYSA-N chloro-methyl-silylsilane Chemical class C[SiH]([SiH3])Cl KQHIGRPLCKIXNJ-UHFFFAOYSA-N 0.000 description 3
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 description 3
- 239000012280 lithium aluminium hydride Substances 0.000 description 3
- DVSDBMFJEQPWNO-UHFFFAOYSA-N methyllithium Chemical compound C[Li] DVSDBMFJEQPWNO-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical group [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- 229910010084 LiAlH4 Inorganic materials 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 125000004429 atom Chemical group 0.000 description 2
- 150000001639 boron compounds Chemical class 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Chemical group BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Chemical group 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- 229910003465 moissanite Inorganic materials 0.000 description 2
- 150000002751 molybdenum Chemical class 0.000 description 2
- 125000002524 organometallic group Chemical group 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 150000004756 silanes Chemical class 0.000 description 2
- 229910021332 silicide Inorganic materials 0.000 description 2
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- IBWGNZVCJVLSHB-UHFFFAOYSA-M tetrabutylphosphanium;chloride Chemical compound [Cl-].CCCC[P+](CCCC)(CCCC)CCCC IBWGNZVCJVLSHB-UHFFFAOYSA-M 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- VOITXYVAKOUIBA-UHFFFAOYSA-N triethylaluminium Chemical compound CC[Al](CC)CC VOITXYVAKOUIBA-UHFFFAOYSA-N 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- VYXHVRARDIDEHS-QGTKBVGQSA-N (1z,5z)-cycloocta-1,5-diene Chemical compound C\1C\C=C/CC\C=C/1 VYXHVRARDIDEHS-QGTKBVGQSA-N 0.000 description 1
- 239000005046 Chlorosilane Substances 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910013627 M-Si Inorganic materials 0.000 description 1
- 229910020968 MoSi2 Inorganic materials 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 229910009052 W5Si3 Inorganic materials 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 150000001345 alkine derivatives Chemical class 0.000 description 1
- 239000002168 alkylating agent Substances 0.000 description 1
- 229940100198 alkylating agent Drugs 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 238000007098 aminolysis reaction Methods 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 1
- 125000001246 bromo group Chemical group Br* 0.000 description 1
- 150000001728 carbonyl compounds Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- KOPOQZFJUQMUML-UHFFFAOYSA-N chlorosilane Chemical class Cl[SiH3] KOPOQZFJUQMUML-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000004696 coordination complex Chemical class 0.000 description 1
- JAGHDVYKBYUAFD-UHFFFAOYSA-L cyclopenta-1,3-diene;titanium(4+);dichloride Chemical compound [Cl-].[Cl-].[Ti+4].C1C=CC=[C-]1.C1C=CC=[C-]1 JAGHDVYKBYUAFD-UHFFFAOYSA-L 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000005054 phenyltrichlorosilane Substances 0.000 description 1
- 238000006303 photolysis reaction Methods 0.000 description 1
- 230000015843 photosynthesis, light reaction Effects 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical group [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- PFUVRDFDKPNGAV-UHFFFAOYSA-N sodium peroxide Chemical compound [Na+].[Na+].[O-][O-] PFUVRDFDKPNGAV-UHFFFAOYSA-N 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 150000003608 titanium Chemical class 0.000 description 1
- 239000012485 toluene extract Substances 0.000 description 1
- ORVMIVQULIKXCP-UHFFFAOYSA-N trichloro(phenyl)silane Chemical compound Cl[Si](Cl)(Cl)C1=CC=CC=C1 ORVMIVQULIKXCP-UHFFFAOYSA-N 0.000 description 1
- LALRXNPLTWZJIJ-UHFFFAOYSA-N triethylborane Chemical compound CCB(CC)CC LALRXNPLTWZJIJ-UHFFFAOYSA-N 0.000 description 1
- 150000003658 tungsten compounds Chemical class 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/60—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which all the silicon atoms are connected by linkages other than oxygen atoms
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
- C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
- C04B35/571—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained from Si-containing polymer precursors or organosilicon monomers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G79/00—Macromolecular compounds obtained by reactions forming a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon with or without the latter elements in the main chain of the macromolecule
Abstract
A process for the preparation of preceramic metallopolysilanes is described. The process consists of reacting polysilanes with metallic compounds from which can be generated open coordination sites associated with the metallic element. Such open coordination sites can be generated by the reduction of the metallic compound with an alkali metal reducing agent or by heating a metallic compound which has thermally labile ligands or by the UV irradiation of a carbonyl-containing metallic compound. The metals which can be incorporated into the polysilane include aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum. These metallopolysilanes are useful, when fired at high temperatures, to form metal-containing ceramic materials.
Description
1~38969 PRECERAMIC METALLOPOLYSILANES
This invention relates to the preparation of metallopolysilanes. More specifically, this invention relates to the preparation of metallopolysilanes which contain significant amounts of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium or tantalum. These polymers are useful as chemical intermediates to synthesize other metal-containing organo-silicon materials or polymers. These polymers can also be converted, when fired at high temperatures, to ceramic materials.
What is disclosed herein is a novel process to obtain metallopolysilanes by reacting polysilanes with certain metal-containing compounds or complexes. The metals are oxidatively added to the polysilane. Polysilanes with significantly higher metallic levels, relative to other methods of incorporating the metal components, can be prepared by the processes of this invention.
What is newly discovered is that metallopolysilanes can be prepared by reacting polysilanes with certain metallic compounds under conditions where open or unoccupied coordination sites can be generated.
This invention relates to a method of preparing a metallopolysilane, which method comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open _ -2- 1 33896~
coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane i5 obtained.
This invention also relates to a method for preparing a ceramic material which method consists of heating a metallopolysilane in an inert atmosphere or in a vacuum to a temperature of at least 750C. until the metallopolysilane is converted to a ceramic material, where the metallopoly-silane is prepared by a method which comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane is obtained.
This invention concerns the preparation of metallo-polysilanes by reacting polysilanes with certain metallic compounds or complexes. The polysilanes useful in this invention are characterized by Si-Si bonds in the skeletal backbone. The polysilanes should be capable of being converted to a ceramic material by pyrolysis to elevated temperatures. Preferably, the polysilane should be capable of being converted to a ceramic product in a 20% or more yield; more preferably, the ceramic yield of the polysilane should be greater than about 40%. Such polysilanes are well known in the art. The polysilane may contain units of general structure [R3Si], [R2Si] and [RSi] where each R is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 20 carbon atoms, phenyl radicals, vinyl radicals and radicals of the formula AyX'(3 y)Si(CH2)z~ where A is a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X' is chlorine or bromine and z is an integer _ -3-greater than or equal to 1. Polysilanes useful in this invention may contain silane units such as tMe2Si], [MeSi], tPhMeSi], tPhSi], [ViSi], [MeHSi], [MeViSi], [Ph2Si], [Me3Si]
and the like. Mixtures of polysilanes may also be employed.
The polysilanes of this invention can be prepared by techniques well known in the art. The actual methods used to prepare the polysilanes are not critical. Suitable polysilanes may be prepared by the reaction of organohalo-silanes with alkali metals as described in Noll, Chemistry and Technolo~Y of Silicones, 347-49 (translated 2d Ger. Ed., Academic Press, 1968). More specifically, suitable poly-silanes may prepared by the sodium metal reduction of organo-substituted chlorosilanes as described by West in U.S. Patent 4,260,780 and West et al. in 25 Polym. Preprints 4 (1984).
Preferred polysilanes can be described by the unit formula [RSi]tR2Si] where there are present 0 to 60 mole percent [R2Si] units and 40 to 100 mole percent [RSi] units and where each R is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 20 carbon atoms, phenyl radicals, vinyl radicals and radicals of the formula AyX'(3 y)Si(CH2)z- where A is a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X' is chlorine or bromine and z is an integer greater than or equal to 1. Halogen-containing polysilanes of unit formula [RSi][R2Si], where there are present 0 to 60 mole percent [R2Si] units and 40 to 100 mole percent [RSi] units and where the remaining bonds on silicon are attached to other silicon atoms and chlorine atoms or bromine atoms, can be prepared by the method of Baney et al., U.S. Patent 4,310,651. These halogen-containing polysilanes are generally difficult to handle due to their high reactivity in air. Therefore, polysilanes where the halogen atoms are replaced with less reactive groups are preferred.
Such less reactive groups include alkyl groups, phenyl groups, amine groups, hydrogen atoms and Me3SiO- groups. The halogen atoms may be replaced by more than one type of these groups. The halogen atoms may be replaced with alkyl or phenyl groups by reacting the halogen-containing polysilanes with alkyl or aryl Grignard reagents or alkyl or aryl lithium compounds as described in Baney et al., U.S Patent 4,298,559.
The halogen atoms in the halogen-containing polysilane may also be replaced with amine groups by reacting the halogen-containing polysilane with a aminolysis reagent of general formula NHR'2 where each R' is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 4 carbons atoms and phenyl radicals as described in Baney et al., U.S. Patent 4,314,956; the resulting amino-polysilane contains amino groups of the general formula -~JHR'. The halogen atoms may also be replaced by hydrogen atoms by reacting the halogen-containing polysilane with lithium aluminum hydride as described in Baney, U.S. Patent 4,310,482. The halogen atoms may also be replaced with Me3SiO- groups by reacting the halogen-containing polysilane with Me3SiOSiMe3 as described in Baney, U.S. Patent 4,310,481. These polysilanes are further discussed in Baney et al., 2 Organometallics 859 (1983).
Still other polysilanes may be used in the practice of this invention.
The metallic compound must be capable of becoming coordinatively unsaturated; that is, the metallic compound must be capable of generating or forming open or unoccupied coordination sites. There are three general methods of generating such sites associated with the metal element in the metallic compound.
The first method is the alkali metal reduction of the metallic compound. Open coordination sites may be generated from reducible metal compounds by reaction with alkali metals. By the general term "alkali metal'~, we mean to include both Group IA alkali metals and Group IIA alkaline earth metals. Preferred alkali metals include lithium, sodium, potassium and magnesium. This method is carried out by combining the polysilane, metallic compound and the reducing agent at room temperature. If desired, higher or lower temperatures may be used. Suitable reducible metallic compounds are of the formula Cp2MX2 where M is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, X is halogen (preferably chlorine) and Cp is a cyclopentadienyl group. These cyclopentadienyl compounds are generally commercially available. The reduction of such complexes are discussed in Kool et al., 320 J. Organometallic Chem. 37 (1987) and Sikora et al., 24 Inor~anic Syntheses 147 (J. Shreeve, ed., Wiley-Interscience, 1986).
The second method of generating open coordination sites is by heating a mixture of the polysilane and a metallic compound which contains thermally labile ligands to a temperature less than or equal to about 175C. For polysilanes which contain amine groups, suitable metallic compounds with thermally labile ligands include organic aluminum compounds of formula R''3Al and organic boron compounds of formula R''3B where R'' is an alkyl radical containing 1 to 4 carbon atoms. Preferred organic aluminum and boron compounds are triethyl aluminum and triethyl boron.
Other suitable metallic compounds with thermally labile ligands include compounds of formula (MeCN)3M'(CO)3 where M' is molybdenum or tungsten. Also suitable are alkene and alkyne metal carbonyl compounds where the metal is chromium, molybdenum or tungsten. Examples of such compounds can be described by the general formula QM''(CO)4 where Q is _ -6-cycloheptatriene, cyclo-octa-1,5-diene, 2,2,1-bicyclohepta-2,5-diene or similar thermally labile groups and M'' is chromium, molybdenum or tungsten. These chromium, molybdenum or tungsten compounds may be used with all polysilanes; amine groups, although they may be present, are not required.
The third method of generating open coordination sites is by exposure of a carbonyl-containing metallic compound, in the presence of the polysilane, to W
irradiation. The metallic compound must contain at least one carbonyl ligand which can be removed under the influence of W irradiation. Metallic compounds which contain two or more carbonyl ligands are preferred. Examples of such suitable carbonyl-containing compounds include compounds of general formula (C6H6)M''(C0)3 and compounds of general formula M''(C0)6 where M'' is chromium, molybdenum or tungsten. Such carbonyl-containing metallic compounds and their photolysis are described in Cotton & Wilkinson, Advanced Inor~anic Chemistry 1049-79 (4th ed., Wiley-Interscience, 1980).
Metallopolysilanes containing two or more metals selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum may be also prepared by the methods of this invention. Such mixed metallopolysilanes can be prepared by either the addition of the different metals at the same time or by sequential addition of the different metals.
The polysilanes and metallic compounds should be reacted in an inert, essentially anhydrous atmosphere. Such reaction conditions help prevent excessive oxygen incorporation into the resulting metallopolysilanes and the occurrence of possible side reactions. By "essentially anhydrous", we mean that reasonable efforts are made to exclude water from the system during the reaction; the _ -7-absolute exclusion of water is not required. Generally, the inert atmosphere is argon or nitrogen.
Although not wishing to be limited by theory, it is thought that once an open or coordinatively unsaturated site is generated in the metallic compound, in the presence of a polysilane, the resulting metallic complex is oxidatively added across a Si-Si bond. In other words, the following reactions are thought to occur:
LnM ---> ML(n 1) and ML(n l) + Si-Si ---> Si-M-Si L(n- 1 ) where M represents the metal atom and L represents the ligands. The incorporation of aluminum and boron is thought to occur through a different mechanism by reaction of the metallic compound with the amino group:
Si-SiNHR' + R' '3Al ---> R''H + Si-SiNAlR''2.
R' This reaction may proceed further:
Si-SiNHR' + Si-SiNAlR''2 ---> R''H + SiSiN-ll-NSiSi.
1, 1 1 R R' R' Similar reactions may occur for the boron-containing compounds. In any event, by the practice of this invention, a metallic-containing group is incorporated into the polysilane.
The metallopolysilanes prepared in this invention generally contain at least about 0.5 weight percent of the metal. It is generally preferred that the metal content of ~ 338969 _ -8-the metallopolysilane is between about 2 and 10 weight percent; more preferably the metal content is between 4 and 10 weight percent. But the metal content, if desired, can be as high as 20 to 25 weight percent.
The metallopolysilane of this invention may be pyrolyzed in an inert atmosphere, in a vacuum or in an ammonia atmosphere at a temperature of at least 750C. to give a ceramic material. Pyrolysis under an ammonia atmosphere should tend to form nitride-containing ceramic materials. Generally, pyrolysis under an inert atmosphere or vacuum is preferred. The polymers may be shaped first (such as an extruded fiber) and then fired to give a ceramic material. Or the polymers may be filled with ceramic type fillers and then fired to obtained filled ceramic materials.
Additionally, pellets, composites, flakes, powders and other articles may be prepared by pyrolysis of the metallopoly-silanes of this invention. The ceramic materials produced by the pyrolysis of the metallopolysilanes of this invention generally contain between 2 and 30 weight percent of the metal. Preferably, the ceramic materials contain about 5 to 10 weight percent of the metal. The metal in the ceramic can be in the form of a metal carbide and/or a metal silicide;
other forms or phases of the metal may also be present. The presence of a metal carbide or silicide may influence the phase composition of the silicon carbide in the ceramic material. The presence of the metal in the ceramic material may increase the wear resistance of the ceramic material; the metal components may also allow for different electrical or magnetic properties in the ceramic materials.
So that those skilled in the art can better appreciate and understand the invention, the following examples are given. Unless otherwise indicated, all percentages are by weight. Throughout the specification "Me"
13389~9 represents a methyl group, "Ph" represents a phenyl group, "Vi" represents a vinyl group and "Cp" represents a cyclo-pentadienyl group. In the following examples, the analytical methods used were as follows:
Carbon, hydrogen and nitrogen were determined on a Control Equipment Corporation 240-XA Elemental Analyzer.
Oxygen analysis was done on a "Leco" Oxygen A~alyzer eq~pped with an Oxygen Determinator 316 (Model 783700) and an Electrode Furnace EF100. Silicon was determined by a fusion technique which consisted of converting the silicon material to soluble forms of silicon and analyzing the solute for total silicon by atomic absorption spectrometry. Metal analyses were carried out by fusing the polymers or ceramic materials with sodium peroxide in a closed nickel bomb and then dissolving the fusinate in an aqueous system. The metal was analyzed by either atomic adsorption spectrometry or inductively coupled plasma-atomic emission spectrometry.
Molecular weights were determined using gel permeation chromatography (GPC) with a "Waters" GPC equipped with a model 600E systems controller, a model 490 W and model 410 Differential Diffractometer detectors; all values are relative to polystyrene. IR spectra were recorded on a "Nicolet" 5 DX spectrometer. Pyrolysis was carried out in an "Astro" graphite element tube furnace Model 1000-3060-FP12 equipped with an ~Eurotherm"- Controller/Programmer Model 822.
Powder X-ray analyses were performed on a "Norelco"
diffractometer interfaced with a HP 3354 computer. Oxidative stability of the ceramic material was evaluated by heating a powdered sample of the ceramic material to 1200C. for 12 hours in air. Thermal stability of the ceramic material was evaluated by firing a powdered sample of the ceramic material to 1800C. for 1 hour under argon.
* Trademark (each instance) ,~
-lo- 133~9 Example 1 (A). Preparation of a chlorine-containing methyl-polysilane. This polysilane was prepared using the general procedure of U.S. Patent 4,310,651. A mixture of methyl-chlorodisilanes containing about 48% (C12MeSi)2, 40%
C12MeSiSiMe2Cl and 12% (ClMe2Si)2 was placed in a three-neck round bottom flask under an argon purge. The flask was equipped with a glass inlet tube, overhead stirrer, temperature programmer probe and a distillation head. About 1.0% tetrabutylphosphonium chloride catalyst from Aldrich Chemical Co. was added. The reaction mixture was then heated to 250C. at 2C./min. while byproducts were removed by distillation. The reaction temperature was held at 250C.
for about 45 minutes and then cooled to room temperature. A
pale yellow polymer was obtained in about 15% yield based on the total weight of the reactants and stored under an inert atmosphere.
(B). Preparation of a chlorine-containing phenyl-methylpolysilane. This polysilane was also prepared using the general procedure of U.S. Patent 4,310,651. A mixture of methylchlorodisilanes (2083.8 g, containing about 48%
(C12MeSi)2, 40% C12MeSiSiMe2Cl and 12% (ClMe2Si)2) and phenyltrichlorosilane (91.0 g) was reacted as described in Example l(A), yielding 295.0 g (13.6%) product. This polysilane contained 40.1% silicon, 29.9% carbon, 0.2% oxygen and 6.0% hydrogen.
(C). Preparation of a methyl-containing methylpolysilane. About 25.0 g of the chlorine-containing methylpolysilane of Example l(A) (containing about 0.15 moles chlorine) was placed, under argon, in a three-neck flask equipped with a gas inlet tube, overhead stirrer and a distillation head. The polymer was dissolved in about 200 mL
toluene, cooled in an ice bath and then alkylated with methyllithium (0.2 moles) in diethyl ether. The reaction mixture was warmed to room temperature and then heated to a distillation head temperature of about 100C. while removing the volatile byproducts. The resulting slurry was cooled in an ice bath and any residual alkylating agent was neutralized with aqueous ammonium chloride. The toluene layer was dried with MgS04, filtered and dried by stripping to 200C. A
white polymer (18.0 g) was obtained.
(D). Preparation of a methyl-containing phenyl-methylpolysilane. The chlorine-containing phenylmethylpoly-silane of Example l(B) (45.0 g, about 0.25 moles chlorine) was methylated with methyllithium (250 mL of 1.3M solution in diethyl ether) using a procedure similar to Example l(C). A
yellow, resinous solid (20.5 g) was obtained. GPC molecular weight: Mn = 963, Mw = 1789; the glass transition temperature was 100.4C.
(E). Preparation of a hydrogen-containing methyl-polysilane. LiAlH4 (12.0 g) was placed in a one liter 3-neck flask (equipped with an overhead stirrer, septa and argon inlet) under an argon atmosphere. Then 200 mL freshly di~tilled toluene and 60.0 g of the chlorine-containing polysilane of Example l(A) in 250 mL toluene was added. The resulting slurry was stirred at room temperature for about 15 hours. The reaction mixture was cooled in an ice bath at which time any excess LiAlH4 was destroyed by slowly adding 12 mL water, 12 mL of 15% aqueous NaOH and then 36 mL water.
The slurry was filtered and then stirred over Na2SO4 for about two hours. After a second filtration, toluene was removed by distillation. A hydrogen-containing methylpoly-silane was obtained (25.7 g, 51.4%). The presence of SiH was confirmed by IR. GPC molecular weight: Mn = 1202, Mw = 2544. The polymer contained 47.0% silicon, 20.6%
carbon, 2.3% oxygen, 7.4% chlorine, 0.20% nitrogen and 6.37 hydrogen.
-12- 1~389~9 (F). Preparation of an NH2-containing phenylmethylpolysilane. A chlorine-containing phenylmethyl-polysilane similar to that described in Example l(B) was dissolved in about 1500 mL toluene and cooled to -78C.
Anhydrous ammonia was rapidly bubbled through the solution for about two hours. The reaction mixture was warmed to room temperature and the excess ammonia was allowed to distill off. The solution was filtered and the filtrate concentrated under vacuum. The NH2-containing phenylmethylpolysilane was obtained in 12.1% yield.
Example 2 The methyl-containing methylpolysilane (10.0 g) of Example l(C) was reacted with 5.0 g (0.02 moles) bis(cyclo-pentadienyl)titanium dichloride and 2.2 g (0.09 moles) magnesium metal in 200 mL tetrahydrofuran for 20 hours at room temperature. The color of the slurry changed from red, to green and finally to a dark red-brown. The solvent was removed at 100C. under vacuum. The gummy solid was extracted with toluene until the toluene was colorless. The toluene extracts were combined and filtered. The toluene was removed at 150C., leaving 12.0 g (83.9% yield) of the red-brown polymer containing 36.6% carbon, 7.0% hydrogen, 0.7% oxygen, 33.6% silicon and 4.0% titanium. The glass transition temperature of the titanium-containing polymer was 140C. A sample of this titanium-containing polysilane was converted to a ceramic material with a char yield of 69.3% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 36.0% carbon, 44.7% silicon, 0.73% oxygen and 7.3% titanium. The ceramic material had 97.1% mass retention and contained 24.0% oxygen when evaluated for oxidative stability. The ceramic material had 93.7% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 2% alpha-SiC, 58% beta-SiC and 10%
TiC.
Example 3 The methyl-containing methylpolysilane (5.0 g) of Example l(C) and (MeCN)3W(C0)3 (1.0 g) were placed in a 250 mL flask under argon along with 100 mL tetrahydrofuran; the polysilane and a portion of the metal complex were soluble.
The stirred sl~rry (pale yellow-green) was heated to 100C.
for 24 hours; a dark black slurry was obtained. After removal of the solvent under vacuum at 100C., the residue was extracted with toluene until colorless. The combined extracts were filtered. After removal of the solvent at 150C., a black polymer was obtained (4.8 g, 84.8% yield).
The tungsten-containing polymer contained 29.0% carbon, 7.2%
hydrogen, 4.1% oxygen, 50.6% silicon and 4.7% tungsten. GPC
molecular weight: Mn = 1277, Mw = 3392. An IR spectrum was recorded with C0-stretching frequencies observed at 1975 (s), 1940 (m) and 1890 (w) cm 1. The glass transition temperature of the tungsten-containing polymer was 60C. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 66.7% by pyrolysis to 1200C. at 5C./min and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 24.2% carbon, 47.9% silicon, 5.7% oxygen and 7.1%
tungsten. The ceramic material had 103.8% mass retention and contained 10.8% oxygen when evaluated for oxidative stability. The ceramic material had 86.7% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 50% beta-SiC, 30% WSi2 and 20%
w5si2 .
Example 4 The methyl-containing methylpolysilane (2.0 g) of Example l(C) and (MeCN)3W(C0)3 (4.0 g) were reacted using the same procedure as Example 3. A toluene soluble black polymer (2.8 g, 60.3%) was obtained which contained 24.2% carbon, 5.3% hydrogen, 12.3% oxygen, 35.6% silicon and 20.9%
tungsten. An IR spectrum was recorded with CO-stretching frequencies observed at 1962 (s), 1933 (m) and 1868 (vs) cm 1. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 61.9% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 19.8% carbon, 45.0% silicon, 4.7% oxygen and 26.3~ tungsten. The ceramic material had 94.5% mass retention and contained 17.7% oxygen when evaluated for oxidative stability. The ceramic material had 91.9% mass retention when tested for thermal stability. Qualitative X-ray analysis indicated the presence of alpha-SiC, beta-SiC
and WSi2.
Example 5 A 5.0 g sample of the methyl-containing methylpoly-silane of Example l(C) was treated with 1.0 g (MeCN)3Mo(C0)3 in the same manner as in Example 3. A black polymer (5.0 g, 89.4%) was obtained which contained 29.1% carbon, 7.4%
hydrogen, 3.1% oxygen, 51.5% silicon and 4.1% molybdenum. An IR spectrum was recorded with C0-stretching frequencies observed at 2023 (m), 1883 (s), 1834 (s) and 1784 (m) cm 1.
The glass transition temperature of the molybdenum-containing polymer was 185C. A sample of this molybdenum-containing polysilane was converted to a ceramic material with a char yield of 66.0% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere.
The resulting ceramic char contained 24.8% carbon, 58.1%
silicon, 5.1% oxygen and 6.7% molybdenum. The ceramic material had 103.8% mass retention and contained 12.9% oxygen when evaluated for oxidative stability. The ceramic material ~ -15- 1~38~69 had 86.9% mass retention when tested for thermal stability.
Quantitative X-ray analysis indicated about 10% alpha-SiC, 62% beta-SiC and 25% MoSi2.
The methyl-containing phenylmethylpolysilane (7.0 g) of Example l(D), molybdenum hexacarbonyl (3.0 g) and 250 mL toluene was placed in a 500 mL quartz Schlenk reactor equipped with a reflux condenser. T~he resulting clear solution was irradiated with a medium pressure UV lamp for one hour. The irradiation intensity was sufficient to reflux the reaction mixture. The resulting red-black solution was stripped at 100C. and the residue was extracted with toluene until colorless. The combined extracts were filtered. Upon removal of the solvent at 150C., 7.7 g of a red-black polymer was obtained. The molybdenum-containing polymer contained 37.9% carbon, 7.6% hydrogen, 2.9% oxygen, 45.170 silicon and 2.6% molybdenum. GPC molecular weight:
Mn = 705~ Mw = 1083. An IR spectrum was recorded with C0-stretching frequencies observed at 1967 (m), 1940 (s) and 1898 (m) cm 1. The glass transition temperature of the molybdenum-containing polymer was 129.3C. A sample of this molybdenum-containing polysilane was converted to a ceramic material with a char yield of 64.8% by pyrolysis to 1200C.
at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 31.6%
carbon, 53.1% silicon, 5.3% oxygen and 5.0% molybdenum. The ceramic material had 101.8% mass retention and contained 10.7% oxygen when evaluated for oxidative stability. The ceramic material had 86.2% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 42% alpha-SiC and 55% beta-SiC.
-16- 13389~9 Example 7 A 7.0 g sample of the methyl-containing phenyl-methylpolysilane of Example l(D) and 3.0 g W(C0)6 was treated with W irradiation in the same manner as in Example 6. A
red-black polymer (8.0 g) was obtained which contained 36.5%
carbon, 7.2% hydrogen, 4.5% oxygen, 41.0% silicon and 5.9%
tungsten. An IR spectrum was recorded with C0-stretching frequencies observed at 1975 (s), 1925 (vs) and 1898 (s) cm 1. The glass transition temperature of the tungsten-containing polymer was 164C. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 67.8% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 24.8%
carbon, 51.2% silicon, 6.2% oxygen and 7.1% tungsten. The ceramic material had 102.9% mass retention and contained 13.9% oxygen when evaluated for oxidative stability. The ceramic material had 85.8% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 26% alpha-SiC, 50% beta-SiC and 20% of an unidentified phase.
Example 8 The hydrogen-containing methylpolysilane (4.0 g) of Example l(E) and 1.0 g (MeCN)3W(C0)3 were reacted using the same procedure as Example 3 except that the mixture was heated to 120C. for 24 hours. A black polymer (4.7 g) was obtained which contained 20.7% carbon, 5.4% hydrogen, 2.3%
oxygen, 44.2% silicon and 5.5% tungsten. An IR spectrum was recorded with C0-stretching frequencies observed at 2066 (m), 1975 (m), 1933 (s) and 1898 (s) cm 1. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 81.7% by pyrolysis to 1200C.
at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 23.9%
1'~38~9 carbon, 57.4% silicon, 6.3% oxygen and 7.9% tungsten. The ceramic material had 102.47O mass retention and contained 10.8% oxygen when evaluated for oxidative stability. The ceramic material had 87.5% mass retention when tested for thermal stability. Qualitative X-ray analysis indicated the presence of beta-SiC, W5Si3 and WSi2.
Example 9 The NH2-containing phenylmethylpolysilane (19.3 g) of Example l(F) was dissolved in 300 mL of degassed toluene;
triethyl aluminum (10.2 g, 0.089 moles) was then added with stirring. The reaction mixture was refluxed for about two hours and then stirred at room temperature for 60 hours.
After filtration and concentration of the filtrate under vacuum, 15.2 g of a toluene soluble polymer was obtained.
This polymer contained 38.9% carbon, 8.6% hydrogen and 30.1%
silicon. A sample of this aluminum-containing polysilane was converted to a ceramic material with a char yield of 66.7% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 30.7% carbon, 45.7% silicon and 13.0%
aluminum.
Example 10 This example is included for comparative purposes only. A tungsten-containing polysilane was prepared from a mixture of methylchlorodisilanes, W(C0)6 and tetrabutyl-phosphonium chloride using the procedure of U.S. Patent 4,762,895. The resulting tungsten-containing polysilane was methylated using methyllithium. An IR spectra of the resulting polysilane exhibited C0-stretching frequencies at 1919 (vs) and 1869 (s) cm 1. A comparison with the IR
spectra of the tungsten-containing polysilane prepared by the method of the present invention in Example 7, where the C0-stretching frequencies were 1975 (s), 1925 (vs) and 1898 (s) cm 1, shows that the metallopolysilanes of the present invention are different from the polysilanes of the prior art. The IR spectra of the tungsten-containing polysilane prepared by the method of the present invention in Examples 3, 4 and 7 also show the differences.
This invention relates to the preparation of metallopolysilanes. More specifically, this invention relates to the preparation of metallopolysilanes which contain significant amounts of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium or tantalum. These polymers are useful as chemical intermediates to synthesize other metal-containing organo-silicon materials or polymers. These polymers can also be converted, when fired at high temperatures, to ceramic materials.
What is disclosed herein is a novel process to obtain metallopolysilanes by reacting polysilanes with certain metal-containing compounds or complexes. The metals are oxidatively added to the polysilane. Polysilanes with significantly higher metallic levels, relative to other methods of incorporating the metal components, can be prepared by the processes of this invention.
What is newly discovered is that metallopolysilanes can be prepared by reacting polysilanes with certain metallic compounds under conditions where open or unoccupied coordination sites can be generated.
This invention relates to a method of preparing a metallopolysilane, which method comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open _ -2- 1 33896~
coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane i5 obtained.
This invention also relates to a method for preparing a ceramic material which method consists of heating a metallopolysilane in an inert atmosphere or in a vacuum to a temperature of at least 750C. until the metallopolysilane is converted to a ceramic material, where the metallopoly-silane is prepared by a method which comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane is obtained.
This invention concerns the preparation of metallo-polysilanes by reacting polysilanes with certain metallic compounds or complexes. The polysilanes useful in this invention are characterized by Si-Si bonds in the skeletal backbone. The polysilanes should be capable of being converted to a ceramic material by pyrolysis to elevated temperatures. Preferably, the polysilane should be capable of being converted to a ceramic product in a 20% or more yield; more preferably, the ceramic yield of the polysilane should be greater than about 40%. Such polysilanes are well known in the art. The polysilane may contain units of general structure [R3Si], [R2Si] and [RSi] where each R is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 20 carbon atoms, phenyl radicals, vinyl radicals and radicals of the formula AyX'(3 y)Si(CH2)z~ where A is a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X' is chlorine or bromine and z is an integer _ -3-greater than or equal to 1. Polysilanes useful in this invention may contain silane units such as tMe2Si], [MeSi], tPhMeSi], tPhSi], [ViSi], [MeHSi], [MeViSi], [Ph2Si], [Me3Si]
and the like. Mixtures of polysilanes may also be employed.
The polysilanes of this invention can be prepared by techniques well known in the art. The actual methods used to prepare the polysilanes are not critical. Suitable polysilanes may be prepared by the reaction of organohalo-silanes with alkali metals as described in Noll, Chemistry and Technolo~Y of Silicones, 347-49 (translated 2d Ger. Ed., Academic Press, 1968). More specifically, suitable poly-silanes may prepared by the sodium metal reduction of organo-substituted chlorosilanes as described by West in U.S. Patent 4,260,780 and West et al. in 25 Polym. Preprints 4 (1984).
Preferred polysilanes can be described by the unit formula [RSi]tR2Si] where there are present 0 to 60 mole percent [R2Si] units and 40 to 100 mole percent [RSi] units and where each R is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 20 carbon atoms, phenyl radicals, vinyl radicals and radicals of the formula AyX'(3 y)Si(CH2)z- where A is a hydrogen atom or an alkyl radical containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X' is chlorine or bromine and z is an integer greater than or equal to 1. Halogen-containing polysilanes of unit formula [RSi][R2Si], where there are present 0 to 60 mole percent [R2Si] units and 40 to 100 mole percent [RSi] units and where the remaining bonds on silicon are attached to other silicon atoms and chlorine atoms or bromine atoms, can be prepared by the method of Baney et al., U.S. Patent 4,310,651. These halogen-containing polysilanes are generally difficult to handle due to their high reactivity in air. Therefore, polysilanes where the halogen atoms are replaced with less reactive groups are preferred.
Such less reactive groups include alkyl groups, phenyl groups, amine groups, hydrogen atoms and Me3SiO- groups. The halogen atoms may be replaced by more than one type of these groups. The halogen atoms may be replaced with alkyl or phenyl groups by reacting the halogen-containing polysilanes with alkyl or aryl Grignard reagents or alkyl or aryl lithium compounds as described in Baney et al., U.S Patent 4,298,559.
The halogen atoms in the halogen-containing polysilane may also be replaced with amine groups by reacting the halogen-containing polysilane with a aminolysis reagent of general formula NHR'2 where each R' is independently selected from the group consisting of hydrogen, alkyl radicals containing 1 to 4 carbons atoms and phenyl radicals as described in Baney et al., U.S. Patent 4,314,956; the resulting amino-polysilane contains amino groups of the general formula -~JHR'. The halogen atoms may also be replaced by hydrogen atoms by reacting the halogen-containing polysilane with lithium aluminum hydride as described in Baney, U.S. Patent 4,310,482. The halogen atoms may also be replaced with Me3SiO- groups by reacting the halogen-containing polysilane with Me3SiOSiMe3 as described in Baney, U.S. Patent 4,310,481. These polysilanes are further discussed in Baney et al., 2 Organometallics 859 (1983).
Still other polysilanes may be used in the practice of this invention.
The metallic compound must be capable of becoming coordinatively unsaturated; that is, the metallic compound must be capable of generating or forming open or unoccupied coordination sites. There are three general methods of generating such sites associated with the metal element in the metallic compound.
The first method is the alkali metal reduction of the metallic compound. Open coordination sites may be generated from reducible metal compounds by reaction with alkali metals. By the general term "alkali metal'~, we mean to include both Group IA alkali metals and Group IIA alkaline earth metals. Preferred alkali metals include lithium, sodium, potassium and magnesium. This method is carried out by combining the polysilane, metallic compound and the reducing agent at room temperature. If desired, higher or lower temperatures may be used. Suitable reducible metallic compounds are of the formula Cp2MX2 where M is titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, X is halogen (preferably chlorine) and Cp is a cyclopentadienyl group. These cyclopentadienyl compounds are generally commercially available. The reduction of such complexes are discussed in Kool et al., 320 J. Organometallic Chem. 37 (1987) and Sikora et al., 24 Inor~anic Syntheses 147 (J. Shreeve, ed., Wiley-Interscience, 1986).
The second method of generating open coordination sites is by heating a mixture of the polysilane and a metallic compound which contains thermally labile ligands to a temperature less than or equal to about 175C. For polysilanes which contain amine groups, suitable metallic compounds with thermally labile ligands include organic aluminum compounds of formula R''3Al and organic boron compounds of formula R''3B where R'' is an alkyl radical containing 1 to 4 carbon atoms. Preferred organic aluminum and boron compounds are triethyl aluminum and triethyl boron.
Other suitable metallic compounds with thermally labile ligands include compounds of formula (MeCN)3M'(CO)3 where M' is molybdenum or tungsten. Also suitable are alkene and alkyne metal carbonyl compounds where the metal is chromium, molybdenum or tungsten. Examples of such compounds can be described by the general formula QM''(CO)4 where Q is _ -6-cycloheptatriene, cyclo-octa-1,5-diene, 2,2,1-bicyclohepta-2,5-diene or similar thermally labile groups and M'' is chromium, molybdenum or tungsten. These chromium, molybdenum or tungsten compounds may be used with all polysilanes; amine groups, although they may be present, are not required.
The third method of generating open coordination sites is by exposure of a carbonyl-containing metallic compound, in the presence of the polysilane, to W
irradiation. The metallic compound must contain at least one carbonyl ligand which can be removed under the influence of W irradiation. Metallic compounds which contain two or more carbonyl ligands are preferred. Examples of such suitable carbonyl-containing compounds include compounds of general formula (C6H6)M''(C0)3 and compounds of general formula M''(C0)6 where M'' is chromium, molybdenum or tungsten. Such carbonyl-containing metallic compounds and their photolysis are described in Cotton & Wilkinson, Advanced Inor~anic Chemistry 1049-79 (4th ed., Wiley-Interscience, 1980).
Metallopolysilanes containing two or more metals selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum may be also prepared by the methods of this invention. Such mixed metallopolysilanes can be prepared by either the addition of the different metals at the same time or by sequential addition of the different metals.
The polysilanes and metallic compounds should be reacted in an inert, essentially anhydrous atmosphere. Such reaction conditions help prevent excessive oxygen incorporation into the resulting metallopolysilanes and the occurrence of possible side reactions. By "essentially anhydrous", we mean that reasonable efforts are made to exclude water from the system during the reaction; the _ -7-absolute exclusion of water is not required. Generally, the inert atmosphere is argon or nitrogen.
Although not wishing to be limited by theory, it is thought that once an open or coordinatively unsaturated site is generated in the metallic compound, in the presence of a polysilane, the resulting metallic complex is oxidatively added across a Si-Si bond. In other words, the following reactions are thought to occur:
LnM ---> ML(n 1) and ML(n l) + Si-Si ---> Si-M-Si L(n- 1 ) where M represents the metal atom and L represents the ligands. The incorporation of aluminum and boron is thought to occur through a different mechanism by reaction of the metallic compound with the amino group:
Si-SiNHR' + R' '3Al ---> R''H + Si-SiNAlR''2.
R' This reaction may proceed further:
Si-SiNHR' + Si-SiNAlR''2 ---> R''H + SiSiN-ll-NSiSi.
1, 1 1 R R' R' Similar reactions may occur for the boron-containing compounds. In any event, by the practice of this invention, a metallic-containing group is incorporated into the polysilane.
The metallopolysilanes prepared in this invention generally contain at least about 0.5 weight percent of the metal. It is generally preferred that the metal content of ~ 338969 _ -8-the metallopolysilane is between about 2 and 10 weight percent; more preferably the metal content is between 4 and 10 weight percent. But the metal content, if desired, can be as high as 20 to 25 weight percent.
The metallopolysilane of this invention may be pyrolyzed in an inert atmosphere, in a vacuum or in an ammonia atmosphere at a temperature of at least 750C. to give a ceramic material. Pyrolysis under an ammonia atmosphere should tend to form nitride-containing ceramic materials. Generally, pyrolysis under an inert atmosphere or vacuum is preferred. The polymers may be shaped first (such as an extruded fiber) and then fired to give a ceramic material. Or the polymers may be filled with ceramic type fillers and then fired to obtained filled ceramic materials.
Additionally, pellets, composites, flakes, powders and other articles may be prepared by pyrolysis of the metallopoly-silanes of this invention. The ceramic materials produced by the pyrolysis of the metallopolysilanes of this invention generally contain between 2 and 30 weight percent of the metal. Preferably, the ceramic materials contain about 5 to 10 weight percent of the metal. The metal in the ceramic can be in the form of a metal carbide and/or a metal silicide;
other forms or phases of the metal may also be present. The presence of a metal carbide or silicide may influence the phase composition of the silicon carbide in the ceramic material. The presence of the metal in the ceramic material may increase the wear resistance of the ceramic material; the metal components may also allow for different electrical or magnetic properties in the ceramic materials.
So that those skilled in the art can better appreciate and understand the invention, the following examples are given. Unless otherwise indicated, all percentages are by weight. Throughout the specification "Me"
13389~9 represents a methyl group, "Ph" represents a phenyl group, "Vi" represents a vinyl group and "Cp" represents a cyclo-pentadienyl group. In the following examples, the analytical methods used were as follows:
Carbon, hydrogen and nitrogen were determined on a Control Equipment Corporation 240-XA Elemental Analyzer.
Oxygen analysis was done on a "Leco" Oxygen A~alyzer eq~pped with an Oxygen Determinator 316 (Model 783700) and an Electrode Furnace EF100. Silicon was determined by a fusion technique which consisted of converting the silicon material to soluble forms of silicon and analyzing the solute for total silicon by atomic absorption spectrometry. Metal analyses were carried out by fusing the polymers or ceramic materials with sodium peroxide in a closed nickel bomb and then dissolving the fusinate in an aqueous system. The metal was analyzed by either atomic adsorption spectrometry or inductively coupled plasma-atomic emission spectrometry.
Molecular weights were determined using gel permeation chromatography (GPC) with a "Waters" GPC equipped with a model 600E systems controller, a model 490 W and model 410 Differential Diffractometer detectors; all values are relative to polystyrene. IR spectra were recorded on a "Nicolet" 5 DX spectrometer. Pyrolysis was carried out in an "Astro" graphite element tube furnace Model 1000-3060-FP12 equipped with an ~Eurotherm"- Controller/Programmer Model 822.
Powder X-ray analyses were performed on a "Norelco"
diffractometer interfaced with a HP 3354 computer. Oxidative stability of the ceramic material was evaluated by heating a powdered sample of the ceramic material to 1200C. for 12 hours in air. Thermal stability of the ceramic material was evaluated by firing a powdered sample of the ceramic material to 1800C. for 1 hour under argon.
* Trademark (each instance) ,~
-lo- 133~9 Example 1 (A). Preparation of a chlorine-containing methyl-polysilane. This polysilane was prepared using the general procedure of U.S. Patent 4,310,651. A mixture of methyl-chlorodisilanes containing about 48% (C12MeSi)2, 40%
C12MeSiSiMe2Cl and 12% (ClMe2Si)2 was placed in a three-neck round bottom flask under an argon purge. The flask was equipped with a glass inlet tube, overhead stirrer, temperature programmer probe and a distillation head. About 1.0% tetrabutylphosphonium chloride catalyst from Aldrich Chemical Co. was added. The reaction mixture was then heated to 250C. at 2C./min. while byproducts were removed by distillation. The reaction temperature was held at 250C.
for about 45 minutes and then cooled to room temperature. A
pale yellow polymer was obtained in about 15% yield based on the total weight of the reactants and stored under an inert atmosphere.
(B). Preparation of a chlorine-containing phenyl-methylpolysilane. This polysilane was also prepared using the general procedure of U.S. Patent 4,310,651. A mixture of methylchlorodisilanes (2083.8 g, containing about 48%
(C12MeSi)2, 40% C12MeSiSiMe2Cl and 12% (ClMe2Si)2) and phenyltrichlorosilane (91.0 g) was reacted as described in Example l(A), yielding 295.0 g (13.6%) product. This polysilane contained 40.1% silicon, 29.9% carbon, 0.2% oxygen and 6.0% hydrogen.
(C). Preparation of a methyl-containing methylpolysilane. About 25.0 g of the chlorine-containing methylpolysilane of Example l(A) (containing about 0.15 moles chlorine) was placed, under argon, in a three-neck flask equipped with a gas inlet tube, overhead stirrer and a distillation head. The polymer was dissolved in about 200 mL
toluene, cooled in an ice bath and then alkylated with methyllithium (0.2 moles) in diethyl ether. The reaction mixture was warmed to room temperature and then heated to a distillation head temperature of about 100C. while removing the volatile byproducts. The resulting slurry was cooled in an ice bath and any residual alkylating agent was neutralized with aqueous ammonium chloride. The toluene layer was dried with MgS04, filtered and dried by stripping to 200C. A
white polymer (18.0 g) was obtained.
(D). Preparation of a methyl-containing phenyl-methylpolysilane. The chlorine-containing phenylmethylpoly-silane of Example l(B) (45.0 g, about 0.25 moles chlorine) was methylated with methyllithium (250 mL of 1.3M solution in diethyl ether) using a procedure similar to Example l(C). A
yellow, resinous solid (20.5 g) was obtained. GPC molecular weight: Mn = 963, Mw = 1789; the glass transition temperature was 100.4C.
(E). Preparation of a hydrogen-containing methyl-polysilane. LiAlH4 (12.0 g) was placed in a one liter 3-neck flask (equipped with an overhead stirrer, septa and argon inlet) under an argon atmosphere. Then 200 mL freshly di~tilled toluene and 60.0 g of the chlorine-containing polysilane of Example l(A) in 250 mL toluene was added. The resulting slurry was stirred at room temperature for about 15 hours. The reaction mixture was cooled in an ice bath at which time any excess LiAlH4 was destroyed by slowly adding 12 mL water, 12 mL of 15% aqueous NaOH and then 36 mL water.
The slurry was filtered and then stirred over Na2SO4 for about two hours. After a second filtration, toluene was removed by distillation. A hydrogen-containing methylpoly-silane was obtained (25.7 g, 51.4%). The presence of SiH was confirmed by IR. GPC molecular weight: Mn = 1202, Mw = 2544. The polymer contained 47.0% silicon, 20.6%
carbon, 2.3% oxygen, 7.4% chlorine, 0.20% nitrogen and 6.37 hydrogen.
-12- 1~389~9 (F). Preparation of an NH2-containing phenylmethylpolysilane. A chlorine-containing phenylmethyl-polysilane similar to that described in Example l(B) was dissolved in about 1500 mL toluene and cooled to -78C.
Anhydrous ammonia was rapidly bubbled through the solution for about two hours. The reaction mixture was warmed to room temperature and the excess ammonia was allowed to distill off. The solution was filtered and the filtrate concentrated under vacuum. The NH2-containing phenylmethylpolysilane was obtained in 12.1% yield.
Example 2 The methyl-containing methylpolysilane (10.0 g) of Example l(C) was reacted with 5.0 g (0.02 moles) bis(cyclo-pentadienyl)titanium dichloride and 2.2 g (0.09 moles) magnesium metal in 200 mL tetrahydrofuran for 20 hours at room temperature. The color of the slurry changed from red, to green and finally to a dark red-brown. The solvent was removed at 100C. under vacuum. The gummy solid was extracted with toluene until the toluene was colorless. The toluene extracts were combined and filtered. The toluene was removed at 150C., leaving 12.0 g (83.9% yield) of the red-brown polymer containing 36.6% carbon, 7.0% hydrogen, 0.7% oxygen, 33.6% silicon and 4.0% titanium. The glass transition temperature of the titanium-containing polymer was 140C. A sample of this titanium-containing polysilane was converted to a ceramic material with a char yield of 69.3% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 36.0% carbon, 44.7% silicon, 0.73% oxygen and 7.3% titanium. The ceramic material had 97.1% mass retention and contained 24.0% oxygen when evaluated for oxidative stability. The ceramic material had 93.7% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 2% alpha-SiC, 58% beta-SiC and 10%
TiC.
Example 3 The methyl-containing methylpolysilane (5.0 g) of Example l(C) and (MeCN)3W(C0)3 (1.0 g) were placed in a 250 mL flask under argon along with 100 mL tetrahydrofuran; the polysilane and a portion of the metal complex were soluble.
The stirred sl~rry (pale yellow-green) was heated to 100C.
for 24 hours; a dark black slurry was obtained. After removal of the solvent under vacuum at 100C., the residue was extracted with toluene until colorless. The combined extracts were filtered. After removal of the solvent at 150C., a black polymer was obtained (4.8 g, 84.8% yield).
The tungsten-containing polymer contained 29.0% carbon, 7.2%
hydrogen, 4.1% oxygen, 50.6% silicon and 4.7% tungsten. GPC
molecular weight: Mn = 1277, Mw = 3392. An IR spectrum was recorded with C0-stretching frequencies observed at 1975 (s), 1940 (m) and 1890 (w) cm 1. The glass transition temperature of the tungsten-containing polymer was 60C. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 66.7% by pyrolysis to 1200C. at 5C./min and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 24.2% carbon, 47.9% silicon, 5.7% oxygen and 7.1%
tungsten. The ceramic material had 103.8% mass retention and contained 10.8% oxygen when evaluated for oxidative stability. The ceramic material had 86.7% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 50% beta-SiC, 30% WSi2 and 20%
w5si2 .
Example 4 The methyl-containing methylpolysilane (2.0 g) of Example l(C) and (MeCN)3W(C0)3 (4.0 g) were reacted using the same procedure as Example 3. A toluene soluble black polymer (2.8 g, 60.3%) was obtained which contained 24.2% carbon, 5.3% hydrogen, 12.3% oxygen, 35.6% silicon and 20.9%
tungsten. An IR spectrum was recorded with CO-stretching frequencies observed at 1962 (s), 1933 (m) and 1868 (vs) cm 1. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 61.9% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 19.8% carbon, 45.0% silicon, 4.7% oxygen and 26.3~ tungsten. The ceramic material had 94.5% mass retention and contained 17.7% oxygen when evaluated for oxidative stability. The ceramic material had 91.9% mass retention when tested for thermal stability. Qualitative X-ray analysis indicated the presence of alpha-SiC, beta-SiC
and WSi2.
Example 5 A 5.0 g sample of the methyl-containing methylpoly-silane of Example l(C) was treated with 1.0 g (MeCN)3Mo(C0)3 in the same manner as in Example 3. A black polymer (5.0 g, 89.4%) was obtained which contained 29.1% carbon, 7.4%
hydrogen, 3.1% oxygen, 51.5% silicon and 4.1% molybdenum. An IR spectrum was recorded with C0-stretching frequencies observed at 2023 (m), 1883 (s), 1834 (s) and 1784 (m) cm 1.
The glass transition temperature of the molybdenum-containing polymer was 185C. A sample of this molybdenum-containing polysilane was converted to a ceramic material with a char yield of 66.0% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere.
The resulting ceramic char contained 24.8% carbon, 58.1%
silicon, 5.1% oxygen and 6.7% molybdenum. The ceramic material had 103.8% mass retention and contained 12.9% oxygen when evaluated for oxidative stability. The ceramic material ~ -15- 1~38~69 had 86.9% mass retention when tested for thermal stability.
Quantitative X-ray analysis indicated about 10% alpha-SiC, 62% beta-SiC and 25% MoSi2.
The methyl-containing phenylmethylpolysilane (7.0 g) of Example l(D), molybdenum hexacarbonyl (3.0 g) and 250 mL toluene was placed in a 500 mL quartz Schlenk reactor equipped with a reflux condenser. T~he resulting clear solution was irradiated with a medium pressure UV lamp for one hour. The irradiation intensity was sufficient to reflux the reaction mixture. The resulting red-black solution was stripped at 100C. and the residue was extracted with toluene until colorless. The combined extracts were filtered. Upon removal of the solvent at 150C., 7.7 g of a red-black polymer was obtained. The molybdenum-containing polymer contained 37.9% carbon, 7.6% hydrogen, 2.9% oxygen, 45.170 silicon and 2.6% molybdenum. GPC molecular weight:
Mn = 705~ Mw = 1083. An IR spectrum was recorded with C0-stretching frequencies observed at 1967 (m), 1940 (s) and 1898 (m) cm 1. The glass transition temperature of the molybdenum-containing polymer was 129.3C. A sample of this molybdenum-containing polysilane was converted to a ceramic material with a char yield of 64.8% by pyrolysis to 1200C.
at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 31.6%
carbon, 53.1% silicon, 5.3% oxygen and 5.0% molybdenum. The ceramic material had 101.8% mass retention and contained 10.7% oxygen when evaluated for oxidative stability. The ceramic material had 86.2% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 42% alpha-SiC and 55% beta-SiC.
-16- 13389~9 Example 7 A 7.0 g sample of the methyl-containing phenyl-methylpolysilane of Example l(D) and 3.0 g W(C0)6 was treated with W irradiation in the same manner as in Example 6. A
red-black polymer (8.0 g) was obtained which contained 36.5%
carbon, 7.2% hydrogen, 4.5% oxygen, 41.0% silicon and 5.9%
tungsten. An IR spectrum was recorded with C0-stretching frequencies observed at 1975 (s), 1925 (vs) and 1898 (s) cm 1. The glass transition temperature of the tungsten-containing polymer was 164C. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 67.8% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 24.8%
carbon, 51.2% silicon, 6.2% oxygen and 7.1% tungsten. The ceramic material had 102.9% mass retention and contained 13.9% oxygen when evaluated for oxidative stability. The ceramic material had 85.8% mass retention when tested for thermal stability. Quantitative X-ray analysis indicated about 26% alpha-SiC, 50% beta-SiC and 20% of an unidentified phase.
Example 8 The hydrogen-containing methylpolysilane (4.0 g) of Example l(E) and 1.0 g (MeCN)3W(C0)3 were reacted using the same procedure as Example 3 except that the mixture was heated to 120C. for 24 hours. A black polymer (4.7 g) was obtained which contained 20.7% carbon, 5.4% hydrogen, 2.3%
oxygen, 44.2% silicon and 5.5% tungsten. An IR spectrum was recorded with C0-stretching frequencies observed at 2066 (m), 1975 (m), 1933 (s) and 1898 (s) cm 1. A sample of this tungsten-containing polysilane was converted to a ceramic material with a char yield of 81.7% by pyrolysis to 1200C.
at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 23.9%
1'~38~9 carbon, 57.4% silicon, 6.3% oxygen and 7.9% tungsten. The ceramic material had 102.47O mass retention and contained 10.8% oxygen when evaluated for oxidative stability. The ceramic material had 87.5% mass retention when tested for thermal stability. Qualitative X-ray analysis indicated the presence of beta-SiC, W5Si3 and WSi2.
Example 9 The NH2-containing phenylmethylpolysilane (19.3 g) of Example l(F) was dissolved in 300 mL of degassed toluene;
triethyl aluminum (10.2 g, 0.089 moles) was then added with stirring. The reaction mixture was refluxed for about two hours and then stirred at room temperature for 60 hours.
After filtration and concentration of the filtrate under vacuum, 15.2 g of a toluene soluble polymer was obtained.
This polymer contained 38.9% carbon, 8.6% hydrogen and 30.1%
silicon. A sample of this aluminum-containing polysilane was converted to a ceramic material with a char yield of 66.7% by pyrolysis to 1200C. at 5C./min. and holding at 1200C. for two hours under an argon atmosphere. The resulting ceramic char contained 30.7% carbon, 45.7% silicon and 13.0%
aluminum.
Example 10 This example is included for comparative purposes only. A tungsten-containing polysilane was prepared from a mixture of methylchlorodisilanes, W(C0)6 and tetrabutyl-phosphonium chloride using the procedure of U.S. Patent 4,762,895. The resulting tungsten-containing polysilane was methylated using methyllithium. An IR spectra of the resulting polysilane exhibited C0-stretching frequencies at 1919 (vs) and 1869 (s) cm 1. A comparison with the IR
spectra of the tungsten-containing polysilane prepared by the method of the present invention in Example 7, where the C0-stretching frequencies were 1975 (s), 1925 (vs) and 1898 (s) cm 1, shows that the metallopolysilanes of the present invention are different from the polysilanes of the prior art. The IR spectra of the tungsten-containing polysilane prepared by the method of the present invention in Examples 3, 4 and 7 also show the differences.
Claims (8)
1. A method of preparing a metallopolysilane, which method comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane is obtained.
2. A method as defined in claim 1 wherein the open coordination sites are generated by treating the metallic compound with an alkali metal reducing agent where the metallic compound is reducible.
3. A method as defined in claim 1 wherein the open coordination sites are generated by heating the metallic compound to a temperature less than or equal to about 175°C.
where the metallic compound contains thermally labile ligands.
where the metallic compound contains thermally labile ligands.
4. A method as defined in claim 1 wherein the open coordination sites are generated by exposing the metallic compound to UV irradiation where the metallic compound contains at least one carbonyl ligand.
5. A method for preparing a ceramic material which method consists of heating a metallopolysilane in an inert atmosphere, in a vacuum or in an ammonia atmosphere to a temperature of at least 750°C. until the metallopolysilane is converted to a ceramic material, where the metallopolysilane is prepared by a method which comprises (A) contacting a polysilane with a metallic compound capable of generating open coordination sites where the metallic compound contains a metal selected from the group consisting of aluminum, boron, chromium, molybdenum, tungsten, titanium, zirconium, hafnium, vanadium, niobium and tantalum and (B) forming open coordination sites of the metallic compound, in the presence of the polysilane, until a metallopolysilane is obtained.
6. A method as defined in claim 5 wherein the open coordination sites are generated by treating the metallic compound with an alkali metal reducing agent where the metallic compound is reducible.
7. A method as defined in claim 5 wherein the open coordination sites are generated by heating the metallic compound to a temperature less than or equal to about 175°C.
where the metallic compound contains thermally labile ligands.
where the metallic compound contains thermally labile ligands.
8. A method as defined in claim 5 wherein the open coordination sites are generated by exposing the metallic compound to UV irradiation where the metallic compound contains at least one carbonyl ligand.
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US5204381A (en) * | 1990-02-13 | 1993-04-20 | The United States Of America As Represented By The United States Department Of Energy | Hybrid sol-gel optical materials |
US5033681A (en) * | 1990-05-10 | 1991-07-23 | Ingersoll-Rand Company | Ion implantation for fluid nozzle |
DE4036988A1 (en) * | 1990-11-20 | 1992-05-21 | Wacker Chemie Gmbh | PROCESS FOR PREPARING METALOPOLYSILANES AND THEIR USE |
US5204380A (en) * | 1991-08-29 | 1993-04-20 | Massachusetts Institute Of Technology | Preparation of silicon carbide ceramics from the modification of an Si-H containing polysilane |
US5700400A (en) * | 1993-06-15 | 1997-12-23 | Nippon Oil Co., Ltd. | Method for producing a semiconducting material |
US6146559A (en) | 1994-07-28 | 2000-11-14 | Dow Corning Corporation | Preparation of high density titanium diboride ceramics with preceramic polymer binders |
CA2154216A1 (en) | 1994-08-01 | 1996-02-02 | Gregg Alan Zank | Preparation of high density zirconium carbide ceramics with preceramic polymer binders |
US5447893A (en) | 1994-08-01 | 1995-09-05 | Dow Corning Corporation | Preparation of high density titanium carbide ceramics with preceramic polymer binders |
FR2726551B1 (en) * | 1994-11-09 | 1997-01-31 | Flamel Tech Sa | PROCESS FOR PREPARING CERAMIC MATERIALS AND STARTING COMPOSITION LIKELY TO BE USED IN THIS PROCESS |
JP3244020B2 (en) * | 1996-08-27 | 2002-01-07 | 宇部興産株式会社 | Silicon carbide based inorganic fiber and method for producing the same |
US5945362A (en) * | 1996-10-02 | 1999-08-31 | Ube Industries, Ltd. | Silicon carbide fiber having excellent alkali durability |
EP1221433B1 (en) * | 1999-09-13 | 2005-03-09 | Japan Science and Technology Agency | Organometallic bridged polymer for use in preparing ceramic composite material and method for preparing the same |
US7579430B2 (en) * | 2005-09-27 | 2009-08-25 | The United States Of America As Represented By The Secretary Of The Navy | Polymeric material made from siloxane-acetylene polymer containing metal-acetylene complex |
US7700710B2 (en) * | 2005-09-27 | 2010-04-20 | The United States Of America As Represented By The Secretary Of The Navy | Pyrolytic formation of metallic nanoparticles |
US7579424B2 (en) * | 2005-09-27 | 2009-08-25 | The United States Of America As Represented By The Secretary Of The Navy | Ceramic material made from siloxane-acetylene polymer containing metal-acetylene complex |
US7576168B2 (en) * | 2005-09-27 | 2009-08-18 | The United States Of America As Represented By The Secretary Of The Navy | Thermoset material made from siloxane-acetylene polymer containing metal-acetylene complex |
EP3057925B1 (en) * | 2013-10-15 | 2019-11-27 | United Technologies Corporation | Manufacturing process of a preceramic polymer for ceramic including metal boride |
RU2712240C1 (en) * | 2019-05-22 | 2020-01-27 | Акционерное общество "Государственный Ордена Трудового Красного Знамени научно-исследовательский институт химии и технологии элементоорганических соединений" (АО "ГНИИХТЭОС") | Method of producing metal polycarbosilanes |
CN112280050B (en) * | 2020-10-13 | 2021-12-31 | 中国科学院化学研究所 | Hf-Ta-C ceramic solid solution precursor and preparation method thereof |
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JPS52112700A (en) * | 1976-02-28 | 1977-09-21 | Tohoku Daigaku Kinzoku Zairyo | Amorphous organopolysilicone composite for preparing silicone carbide |
US4310651A (en) * | 1979-03-26 | 1982-01-12 | Dow Corning Corporation | Method for preparing silicon carbide |
US4260780A (en) * | 1979-11-27 | 1981-04-07 | The United States Of America As Represented By The Secretary Of The Air Force | Phenylmethylpolysilane polymers and process for their preparation |
JPS56147827A (en) * | 1980-04-17 | 1981-11-17 | Seishi Yajima | Organometallic polymer and its preparation |
US4314956A (en) * | 1980-07-23 | 1982-02-09 | Dow Corning Corporation | High yield silicon carbide pre-ceramic polymers |
US4310482A (en) * | 1980-07-23 | 1982-01-12 | Dow Corning Corporation | High yield silicon carbide pre-polymers |
US4298559A (en) * | 1980-07-23 | 1981-11-03 | Dow Corning Corporation | High yield silicon carbide from alkylated or arylated pre-ceramic polymers |
JPS58213023A (en) * | 1982-06-04 | 1983-12-10 | Ube Ind Ltd | Polymetallosilane and its production |
JPS59161430A (en) * | 1983-03-07 | 1984-09-12 | Tokushu Muki Zairyo Kenkyusho | High polymer substance to be converted into inorganic substance having tic crystalline structure and its preparation |
JPS63128027A (en) * | 1986-11-18 | 1988-05-31 | Ube Ind Ltd | Transition metal-crosslinked polymer containing silicon and titanium or zirconium and production thereof |
US4762895A (en) * | 1987-08-10 | 1988-08-09 | Dow Corning Corporation | Process for the preparation of preceramic metallopolysilanes and the polymers therefrom |
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1989
- 1989-09-26 CA CA000613367A patent/CA1338969C/en not_active Expired - Fee Related
- 1989-10-26 EP EP89311051A patent/EP0367497B1/en not_active Expired - Lifetime
- 1989-10-26 DE DE68926096T patent/DE68926096T2/en not_active Expired - Fee Related
- 1989-10-30 JP JP1280015A patent/JPH02178331A/en active Pending
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US4906710A (en) | 1990-03-06 |
DE68926096T2 (en) | 1996-09-19 |
JPH02178331A (en) | 1990-07-11 |
EP0367497A3 (en) | 1990-12-27 |
EP0367497B1 (en) | 1996-03-27 |
DE68926096D1 (en) | 1996-05-02 |
EP0367497A2 (en) | 1990-05-09 |
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