JPS6261220B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel polymeric material derived from polysilane and titanium alkoxide, and a method for producing the same. Like SiCV, TiC has high hardness and is promising as an excellent heat-resistant material.

A wide range of applications have been developed by using polycarbosilane consisting of [formula] as a precursor, molding it into a fibrous shape or various molded bodies, and firing it. , JP-A-51-139929, JP-A-54-61299, JP-A-54
-82435, JP-A-102311, etc. However, for TiC, conventional CVD methods and inorganic chemical methods are used, so it is difficult to use organic matter as a precursor. Compared to SiC, its applications were limited. The present inventors previously published Japanese Patent Application Laid-Open No. 56-5828,
-9209, JP-A-56-74126, JP-A-56-88877
No. 56-128315, the reaction product of polycarbosilane and polytitanoxane or titanium alkoxide can be converted into SiC-TiC-based inorganic materials,
Although it has been shown that it is useful as a precursor for fibers and other molded bodies, it is inevitable that SiC is the main component, and it can be used as a raw material for the development of even more functional inorganic materials with TiC as the main component. It has become clear that there are limits. Therefore, the present inventors conducted research on raw materials for inorganic materials containing TiC as the main component, and found that the molecular weight
A reaction product of an organosilicon compound having a polysilane structure of 100 to 600 and titanium alkoxide is converted into an inorganic substance having a TiC type crystal structure mainly composed of Ti, C and O by firing in a non-oxidizing atmosphere, Moreover, it has been found that it can be molded into fibrous shapes and various molded bodies, and is useful as a precursor for inorganic materials, leading to the present invention. According to the invention, formula (A): (However, R is a hydrogen atom, methyl group, ethyl group, phenyl group, hydroxyl group, or halogen) (B): (However, R' is an alkyl group) It is mainly composed of structural units (A) and (B), and the structural unit (A) is a formula with a molecular weight of 100 to 600. (n is 2 to 10), provided that the polysilane moiety can contain a small amount of carbosilane bond or siloxane bond, and the structural unit of (B) has the formula (m is 1 to 10) A titanoxane moiety having the structural formula is formed, and the formula is formed from the polysilane moiety and the titanoxane moiety. It is a polymeric substance with a molecular weight of 2 × 10 ² to 10 ⁷ and in some cases contains a branched structure. The polysilane moiety, which is insoluble in organic solvents after hydrolysis and does not melt when heated, has a molecular weight of 100 to 600, and contains 2 to 10 Si atoms, is derived from Ti(OR') _4.
1:1 with titanoxane moiety containing 1 to 10 Ti atoms
When fired in a non-oxidizing atmosphere, Ti
Provided is a polymeric substance that is characterized by being converted into an inorganic substance having a TiC type crystal structure consisting of , C and O. Furthermore, according to the present invention, the polysilane and the titanium alkoxide are added in a quantitative ratio such that the ratio of the number of Ti atoms in the titanium alkoxide to the number of Si atoms in the polysilane is 5:1 to 1:1. Heat in an inert atmosphere, adding a small amount of water if necessary. A method for producing the polymeric substance is provided. The present invention will be explained in detail below. The polymeric substance of the present invention can generally be characterized by the following structure, where n is 2 to 10,
m is 1 to 10, and the molecular weight of the polysilane part is 100 to 10.
600, but the polysilane part does not have to be chain-like, and can be branched, cyclic, or cage-like depending on what polysilane is used as the raw material, and the titanoxane part is not limited to such polytitanoxane. As is clear from the fact that the polymer substance has absorption in the visible absorption spectrum from 370 to 1200 nm and is colored, it is presumed that titanium alkoxide polymers containing six-coordinated Ti and their analogues are also formed. For example, the following structure can be considered (R' is omitted, but it is estimated from the infrared absorption spectrum that some parts are separated during the reaction.) Also, during the reaction It is also clear that adding a small amount of water introduces a titanoxane bond, which is actually a titanoxane bond containing a titanium alkoxide polymer, and the Ti atoms in this titanoxane moiety are 1 to 10.
It is. Although polysilane and titanium alkoxide themselves are known, the polymeric substance derived from polysilane and titanium alkoxide in the present invention has not been known so far, and from the measurement results of gel vermiaction chromatography (GPC), It is a polymer substance with a molecular weight of 2×10 ² to 10 ⁷ , which is much larger than the molecular weight of the raw material polysilane. In addition, from the infrared absorption spectrum of the polymeric substance, the infrared absorption spectrum of the low-boiling point product obtained as a by-product during the synthesis of the polymeric substance, and the measurement results by gas chromatography, it was determined that the reaction occurred in the raw material polysilane. It has become clear that Si-H and Si-OH are active moieties in particular, and they disappear through reaction even at low temperatures.At higher temperatures, alkyl groups such as Si- _CH3 , halogens, and phenyl groups react. Each corresponding compound, e.g.
It generates R′OH, R′H, H ₂ O, H ₂ , CH ₄ , C ₆ H ₆ , but what is particularly noteworthy is the ketone derived from the alcohol of titanium alkoxide, H ₂ , CH ₄ , etc. gas is produced, indicating the complexity of the reaction. This is because the formation of the bond between the polysilane moiety and the titanoxane moiety is caused by which substituent on the Si atom of the raw material polysilane is released. It turned out that this was due to the following. The method for producing the polymeric substance of the present invention includes:
This is a method in which polysilane and titanium alkoxide are heated in an atmosphere inert to the reaction, without a solvent or in an organic solvent, to bond the polysilane part and the titanoxane part.Since the polysilane used is usually liquid, it is a method that does not require a solvent. However, since the raw material polysilane has a high viscosity,
Or it is solid, or titanium alkoxide is a higher alcohol alkoxide and is solid,
When uniform mixing is not possible, it is advantageous to use an organic solvent, and preferred solvents include hexane, benzene, toluene, xylene, and the like. For example, hydrogen or argon is suitable as an inert atmosphere for the reaction; oxidation occurs in air, and raw material polysilane and titanium alkoxy are distilled out before the reaction under reduced pressure, which is not preferable. The reaction temperature is the boiling point when an organic solvent is used, and the reflux temperature required when no organic solvent is used.Then, the solvent or unreacted substances are distilled off and heated at 200 to 450°C. Generally, the temperature is preferably below 400°C to avoid gelation. The reaction time is not particularly important, and the molecular weight is preferably controlled by the reaction temperature. Polysilane, which is one of the starting materials for producing the new polymeric substance in the method of the present invention, has the following structural formula with a molecular weight of 100 to 600. (However, R is a hydrogen atom, a methyl group, an ethyl group, a phenyl group, a hydroxyl group, or a halogen), and in some cases, the above structural units are polysilanes bonded by carbosilane bonds or siloxane bonds, shaped, circular,
Any cage-like structure is acceptable, and the terminal group is the same as the side chain, but if the polysilane unit is bonded by a carbosilane bond or a siloxane bond, the Si atom in this polysilane moiety is The number is 2 to 10 as described later.
The method for producing these polysilanes is known per se. Particularly suitable as the polysilane used as a raw material in the present invention is a method in which linear polydimethylsilane with a high degree of polymerization is thermally decomposed at 500°C or less. This polysilane has a small number of carbosilane bonds in the molecule, but it is advantageous in that it has high reactivity because it has a hydrogen atom as a substituent on the Si atom. Moreover, it is an excellent method for easily obtaining such polysilane. Another starting material for the present invention has the general formula Ti
(OR') ₄ (where R' is an alkyl group) and its manufacturing method is known, but for example, R' is preferably a propyl, isopropyl, or n-butyl group, and titanium diisopropoxybisacetyl Acetonate and the like can also be used. In the method of the present invention, the total Ti in the titanium alkoxide relative to the total number of Si atoms in the polysilane is
A polymer material is produced by adding and heating in a quantity ratio such that the ratio of the number of atoms is 5:1 to 1:1. Through this reaction, a polysilane moiety with a molecular weight of 100 to 600 and containing 2 to 10 Si atoms is produced. A polymer material is obtained which is bonded in a 1:1 ratio with a titanoxane moiety containing 1 to 10 Ti atoms derived from Ti(OR') ₄ . The polymeric material of the present invention may have a branched structure in which the titanoxane moiety is bonded to the polysilane moiety of another chain. If the number of Si atoms in the polysilane moiety in the polymer material obtained by the above method is greater than 10,
When the number of Ti atoms in the titanoxane moiety is greater than 10, the yield of inorganic materials obtained by firing becomes small, or inorganic materials with a TiC type structure cannot be obtained, resulting in SiC, SiO ₂ and oxides between TiO ₂ and TiO. It has become clear that the ratio of the total number of Ti atoms to the total number of Si atoms must be 5:1 to 1:1 in order to obtain an inorganic substance with a TiC type structure. is as described below. The new polymeric substance produced by the method of the present invention is
It has a molecular weight of 2 x 10 ² to 10 ⁷ and is usually a fluid viscous liquid or a thermoplastic substance that softens or melts when heated above room temperature, and is soluble in solvents such as toluene, xylene, and tetrahydrofuran. However, it is susceptible to hydrolysis due to moisture in the air or moisture in the solvent, and when the molecular weight distribution is measured by GPC, the molecular weight distribution shifts to the lower molecular weight side with the passage of time. When heated at low temperature, hydrolysis and gelation proceed simultaneously, making it insoluble in solvents,
It was also revealed that the material did not show any softening due to heating. This phenomenon does not occur in the absence of moisture. This is presumed to be due to the fact that the titanoxane moiety constituting the polymeric material is susceptible to hydrolysis, but this property may be caused by molding or It is extremely useful when used as a sintering aid for molded bodies and then fired to obtain molded bodies of various shapes that maintain their shapes without being deformed due to softening due to heating. The novel polymeric substance of the present invention can be converted into an inorganic substance having a TiC-type crystal structure mainly composed of Ti, C, and O by firing in a non-oxidizing atmosphere such as a vacuum or an inert gas atmosphere. This is a major feature, and in order to achieve this, all of the raw material polysilane must be
The ratio of the total number of Ti atoms in the titanium alkoxide to the number of Si atoms must be added and reacted at a quantitative ratio of 5:1 to 1:1. At this quantitative ratio, the molecular weight is 100 to 600, and the polysilane moiety containing 2 to 10 Si atoms is derived from titanium alkoxide.
1:1 with titanoxane moiety containing 1 to 10 Ti atoms
A bonded polymer substance is formed. When the high molecular weight substance in the present invention is fired,
Although the mechanism of conversion into an inorganic substance with a TiC-type crystal structure consisting mainly of Ti, C, and O is not necessarily clear, the polysilane part that makes up the polymer substance is completely thermally decomposed by heat treatment up to 600°C, producing a large number of radicals. , for example, generates S〓iR ₂ , R・, H・, and these radicals react with Ti and react with oxygen around the Ti atom to exhibit a reducing action and form TiC, and only polytitanoxane is heated. Oxygen-deficient oxides from TiO ₂ of TiO ₂ to TiO produced when decomposed, such as Ti oxides with compositions such as Ti ₇ O ₁₃ , Ti ₆ O ₁₁ , and Ti ₈ O ₁₅ (Comparative Example 1), are reduced. A solid solution phase of TiO and TiO are formed in TiO and TiC.
It is estimated that TiC forms a mixed phase in which TiC is a solid solution and transforms into an inorganic substance having a TiC-type crystal structure consisting of Ti, C, and O as shown in the example. In some cases, it may be possible to contain a large amount, but in general, the yield of inorganic substances obtained may be low, or polycarbosilane may be formed due to thermal decomposition of the polysilane portion, and the polycarbosilane may generate SiC upon firing. So I don't like it. In addition, when the polysilane moiety has one silicon atom, the yield of thermal decomposition products is still low, and when it has a phenyl group with a high yield (Comparative Example 2), a large amount of silicon oxide, carbon, Further heating to a high temperature produces SiC, which is a reaction product of these, which is undesirable. On the other hand, the number of Ti atoms in the titanoxane portion is preferably 1 to 10; if it is more than that, an oxide having more oxygen atoms than TiO as described above is formed, which is not preferable. Furthermore, the molecular weight of the polysilane part forming the polymeric material may be greater than 600, but since most of the polysilane portion is dispersed due to thermal decomposition when the polymeric material is fired, this is effective in increasing the yield of inorganic materials.
100 to 600 is preferable, and the substituents of such polysilanes are substantially methyl groups and ethyl groups, with small amounts of hydrogen, phenyl groups, hydroxyl groups, and halogens. The polymeric substance obtained by the production method of the present invention is a solid that softens or melts when heated, or is a viscous liquid, so it can be made into molded bodies of various shapes, or it can be used as a sintering aid for molded bodies. By subjecting it to the above-mentioned hydrolysis and calcination treatment, inorganic materials with good performance can be obtained, such as fibers, films, ultrafine particles, and other complex-shaped molded bodies. It is useful as a raw material for The present invention will be explained below with reference to Examples. Example 1 Polydimethylsilane with a degree of polymerization of about 35, (-
SiMe ₂ ) _o , 1000g in nitrogen atmosphere from room temperature to 450℃
The resulting product was heated to decompose and the low boiling point products produced were distilled off to obtain about 750 g of polysilane with a molecular weight range of 60 to 600. It was confirmed from infrared absorption spectrum and nuclear magnetic resonance spectrum that this polysilane has approximately 17% hydrogen as a substituent on the Si atom in addition to the methyl group.
It was confirmed that there were almost no carbosilane bonds in this polysilane. Next, 340 g of titanium tetrabutoxy was added to 60 g of the above polysilane, heated while stirring in a nitrogen atmosphere, and refluxed until the temperature rose to 210°C. Next, low-boiling reaction products and unreacted substances were distilled out to 250°C. Heating to ℃ and cooling until the Si to Ti ratio is 1:1.
137 g of a black-green solid polymer substance with a molecular weight of 300 to 2×10 ⁶ was obtained. The polymer material obtained here was heated at 100℃・h ^-1 in vacuum.
The yield of the inorganic material heated to 1400℃ and calcined at 1400℃ for 0.5 hours is 62%, and the result of X-ray powder diffraction measurement using CuK rays of this material shows that the 2θ is 36.2
TiC at ゜, 42.1゜, 60.8゜, 72.7゜, 76.6゜ respectively.
Diffraction peaks corresponding to (111), (200), (220), (113), and (222) diffraction lines were obtained, but these diffraction lines were at higher angles than those observed for conventional TiC. It shows a shift to the side or an overlap of another diffraction line on the high angle side, and this is due to the phase showing the diffraction line on the low angle side where TiO is solid dissolved in TiC and the phase showing the diffraction line on the high angle side where TiC is solid dissolved in TiO. These are phases that show diffraction lines, and both have a TiC type crystal structure, and under similar firing conditions.
The diffraction peaks of inorganic materials calcined to 1200°C show similar diffraction lines with wider half-value widths, so Ti and C
It is presumed that this is caused by an inorganic substance having a TiC-type crystal structure consisting of and O. Example 2 90 to 310 of the polysilane obtained in Example 1
190 g of titanium tetraisopropoxide to 120 g of polysilane with a molecular weight of 200 to 600 and a boiling point of up to ℃.
was added and refluxed under stirring in a nitrogen atmosphere until the temperature rose to 180°C. Next, low-boiling reaction products and unreacted substances were distilled off, heated to 280°C, and then cooled to remove Si and Ti. Molecular weight 1000~ with a ratio of 3:1
129 g of a dark green semi-solid polymeric substance of 10 ⁷ was obtained. The inorganic material obtained by calcining this polymeric material at 1400°C in the same manner as in Example 1 had a yield of 37%, which was also estimated to be due to the inorganic material having a TiC type crystal structure consisting of Ti, C, and O. given the shape. Example 3 114 g of titanium tetraisopropoxide was added to 120 g of the polysilane obtained in Example 1 and refluxed under stirring in a nitrogen atmosphere until the temperature reached 205°C. Next, low-boiling reaction products and unreacted substances were distilled off. The mixture was heated to 350° C. and then cooled to obtain 108 g of a blackish-blue semisolid polymer material with a Si:Ti ratio of 5:1 and a molecular weight of 200 to 5×10 ⁶ . This polymeric material was heated to 1400°C at a temperature increase rate of 100°C x h ^-1 in an Ar stream with a flow rate of 200 c.c.・min ^-1 , and the inorganic material obtained by firing at 1400°C for 0.5 hours was With a yield of 31%, an X-ray diffraction pattern was obtained which was presumed to be due to an inorganic substance having a TiC-type crystal structure composed of Ti, C, and O. Example 4 1 mole of dimethyldichlorosilane and 2 moles of diphenyldichlorosilane were dechlorinated and condensed in xylene with 4 moles of metallic Na to give an average composition of Cl--SiPh ₂ --SiMe ₂
-SiPh ₂ -Cl polysilane was generated and this was hydrolyzed to form disilanol HO-SiPh ₂ -SiMe ₂ -SiPh ₂ -OH. To 114 g of this polysilane, 85 g of titanium tetrabutoxide was added, and then 150 g of xylene was added. After heating with stirring in a nitrogen atmosphere and refluxing, xylene and low boiling point products are distilled out, heated to 200℃, then cooled, and Si and Ti are removed.
130 g of a brown solid polymer substance having a molecular weight of 1000 to 3×10 ⁶ with a ratio of 3:1 was obtained. This polymer material was heated to 1400 ml under the same conditions as in Example 3.
The inorganic material obtained by firing at .degree. C. had a yield of 58% and gave an X-ray diffraction pattern that was presumed to be due to the inorganic material having a TiC type crystal structure consisting of Ti, C, and O. Example 5 The polymer material obtained in Example 2 was dissolved in 10 g of tetrahydrofuran (10 c.c.) and left in the air for 24 hours to be hydrolyzed, and then the tetrahydrofuran was evaporated to obtain a brown resinous substance insoluble in the solvent. . This product did not soften when heated, and when fired at 1400°C in the same manner as in Example 1, the yield was 50%, which is presumed to be due to an inorganic substance having a TiC type crystal structure consisting of Ti, C, and O, and a trace amount of SiO ₂ An X-ray diffraction pattern was given. Comparative Example 1 284 g of titanium tetraisopropoxide was heated to 30°C in a nitrogen atmosphere, and while stirring, 17.4 g of water was added.
Dissolve g in 100 c.c. of isopropyl alcohol and make 2
The mixture was added dropwise over a period of time, and then heated to 240° C. while distilling off a low-boiling reaction product to obtain 134 g of polytitanoxane. This was carried out in the same manner as in Example 1 for 1200
℃ and 1400℃, the yields were 53% and 49%, respectively, but the X-ray diffraction patterns showed that Ti ₇ O ₁₃ , Ti ₆ O ₁₁ , and Ti ₈ O ₁₅ were the main components. ,
No TiC type crystal structure was observed. Comparative Example 2 35.5 g of titanium tetraisopropoxide and 81 g of diphenylsilanediol were mixed and heated to 180°C with stirring in a nitrogen atmosphere to obtain 78 g of polytitanosiloxane with a Si to Ti ratio of 3:1. .
This was heated to 1200°C and 1400°C in the same manner as in Example 1.
The yields of the products calcined at 1200°C were 41% and 27%, respectively, but the X-ray diffraction pattern showed that β-SiC was the main component in addition to the TiC type crystal structure, and at 1200°C, large amounts of SiO ₂ and C were observed. Admitted.

Claims (1)

[Claims] 1 Formula (A): (However, R is a hydrogen atom, a methyl group, an ethyl group,
phenyl group, hydroxyl group or halogen) (B): (However, R′ is an alkyl group) It mainly consists of structural units (A) and (B), and the structural unit (A) is a formula with a molecular weight of 100 to 600. (n is 2 to 10), provided that the polysilane moiety can contain a small amount of carbosilane bond or siloxane bond, and the structural unit of (B) has the formula (m is 1 to 10) A titanoxane moiety having the structural formula is formed, and a formula formed from the polysilane moiety and the titanoxane moiety It is a polymeric substance with a molecular weight of 2 × 10 ² to 10 ⁷ and sometimes containing a branched structure,
It is colored with absorption in the range of 370 to 1200 nm in the visible absorption spectrum, has excellent hydrolyzability, becomes insoluble in organic solvents after hydrolysis, and does not melt when heated, and the polysilane portion containing 2 to 10 Si atoms is Ti. When combined with the titanoxane moiety containing 1 to 10 atoms in a 1:1 ratio and fired in a non-oxidizing atmosphere, it becomes mainly composed of Ti, C, and O.
A polymer substance characterized by being converted into an inorganic substance having a TiC type crystal structure. 2 Polysilane having a molecular weight of 100 to 600 and having the following structural formula (However, R is a hydrogen atom, a lower alkyl group, a phenyl group, a hydroxyl group, or a halogen.) Alternatively, this structural unit is bonded to a polysilane by a carbosilane bond or a siloxane bond, with the general formula Ti(OR') ₄ , (wherein R' is A titanium alkoxide represented by an alkyl group) is added in a quantity ratio such that the ratio of the number of Ti atoms in the titanium alkoxide to the number of Si atoms in the polysilane is 5:1 to 1:1, and an inert atmosphere for the reaction is added. Formula (A) characterized by heating with a small amount of water added as necessary: (However, R is a hydrogen atom, a methyl group, an ethyl group,
phenyl group, hydroxyl group or halogen) (B): (However, R′ is an alkyl group) It mainly consists of structural units (A) and (B), and the structural unit (A) is a formula with a molecular weight of 100 to 600. (n is 2 to 10), provided that the polysilane moiety can contain a small amount of carbosilane bond or siloxane bond, and the structural unit of (B) has the formula (m is 1 to 10) A titanoxane moiety having the structural formula is formed, and a formula formed from the polysilane moiety and the titanoxane moiety It is a polymeric substance with a molecular weight of 2 × 10 ² to 10 ⁷ and sometimes containing a branched structure,
It is colored with absorption in the range of 370 to 1200 nm in the visible absorption spectrum, has excellent hydrolyzability, becomes insoluble in organic solvents after hydrolysis, and does not melt when heated, and the polysilane portion containing 2 to 10 Si atoms is Ti. When combined with the titanoxane moiety containing 1 to 10 atoms in a 1:1 ratio and fired in a non-oxidizing atmosphere, it becomes mainly composed of Ti, C, and O.
A method for producing a polymeric substance, characterized by converting it into an inorganic substance having a TiC-type crystal structure.