JPS6149335B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel organometallic crosslinked block copolymer comprising a polycarbosilane moiety and a polytitanosiloxane moiety. Polycarbosilane, which is a polymer with a main chain skeleton of (-Si-CH ₂ )- and two side chain groups bonded to each silicon atom, is converted into an inorganic carbide SiC by baking, so polycarbosilane It is well known that SiC fibers with good mechanical and thermal properties can be produced by forming SiC fibers into fibers and firing them.
It was disclosed in No. 26527, Japanese Unexamined Patent Publication No. 139929/1983, etc. The present inventors also disclosed in JP-A-54-61299 that the main chain skeleton mainly consists of (-Si-CH ₂ )-,
In addition to this, a small amount of components constituting the main chain skeleton)
It has been disclosed that polycarbosilane containing Si-O)- is particularly excellent as a raw material for producing SiC fibers. The present inventors continued their research on organometallic polymers, and as a result, they discovered a method for producing a new crosslinked block copolymer consisting of a crosslinked polycarbosilane moiety and a polytitanosiloxane moiety, and This organometallic copolymer is an extremely useful polymer because, when molded and fired, it is possible to obtain composite inorganic carbide fibers that have even better performance than SiC fibers obtained from conventional polycarbosilane. I discovered that. The organometallic crosslinked block copolymer obtained by the method of the present invention comprises a polycarbosilane portion (A) having a number average molecular weight of approximately 500 to 10,000 and a polycarbosilane portion (A) having a number average molecular weight of approximately 500 to 10,000.
-10,000 polytitanosiloxane moiety (B) and a number average molecular weight of about 1,000 to 50,000; the polycarbosilane moiety (A) mainly has the formula (-Si-CH ₂ ) It has a main chain skeleton consisting of structural units, and the silicon atom in the formula is a hydrogen atom or a lower alkyl group (preferably 1 to 4 carbon atoms).
The polytitanosiloxane moiety (B) has one or two side chain groups selected from the group consisting of phenyl and phenyl groups;
)- and siloxane bond units (-Si-O-) are randomly bonded, and the ratio of the total number of titanoxane bonds to the total number of siloxane bonds is
30:1 to 1:30, and most of the silicon atoms in the siloxane bond are side chain groups selected from the group consisting of lower alkyl groups (preferably having 1 to 4 carbon atoms) and phenyl groups. most of the titanium atoms in the titanoxane bond have one or two lower alkoxy groups (preferably 1 to 4 carbon atoms) as side chain groups; the polycarbosilane At least one part of the silicon atoms of the part (A) is bonded to at least one part of the silicon atoms and/or titanium atoms of the polytitanosiloxane part (B) via an oxygen atom, thereby forming a polytitanosiloxane part (B). The carbosilane part (A) and the polytitanosiloxane part (B) are crosslinked, and the polycarbosilane part (A) (-Si-
Within the description that the ratio of the total number of pairs of (-Ti-O)-bonding units and (-Si-O)-bonding units of the polytitanosiloxane moiety of the total number of pairs of CH ₂ -) structural units is 100:1 to 1:100. The organometallic crosslinked block copolymer described above is characterized in that: it melts when heated at 100 to 400°C and is soluble in organic solvents. The method of the present invention has (1) a main chain skeleton mainly composed of structural units of the formula (-Si-CH ₂ )- with a number average molecular weight of about 500 to 10,000, in which the silicon atoms are substantially hydrogen. (2) a titanoxane having a number average molecular weight of about 500 to 10,000; It has a main chain skeleton in which bonding units (-Ti-O)- and siloxane bonding units (-Si-O-) are randomly bonded, and the ratio of the total number of titanoxane bonding units to the total number of siloxane bonding units is 30. :1 to 1:30, and most of the silicon atoms of the siloxane bonding unit are side chain groups selected from the group consisting of lower alkyl groups (preferably having 1 to 4 carbon atoms) and phenyl groups. polytitanosiloxane, which has one or two lower alkoxy groups (preferably 1 to 4 carbon atoms), and most of the titanium atoms in the titanoxane bonding unit have one or two lower alkoxy groups (preferably 1 to 4 carbon atoms) as side chain groups. The total number of )-Si-CH ₂ )- structural units of the polycarbosilane versus the )-Ti-O)-bonding units and -)Si of the polytitanosiloxane.
-O)- Mix in a quantitative ratio such that the ratio of the total number of bonding units is within the range of 100:1 to 4:100, and the resulting mixture is placed in an organic solvent and under an atmosphere inert to the reaction. Crosslinking characterized by heating to bond at least one part of the silicon atoms of the polycarbosilane to at least one part of the silicon atoms and/or titanium atoms of the polytitanosiloxane via oxygen atoms. This is a method for producing an organometallic crosslinked block copolymer having a number average molecular weight of 1,000 to 50,000, which is composed of a polycarbosilane part and a polytitanosiloxane part. Below, the organometallic crosslinked block copolymer of the present invention (hereinafter sometimes simply referred to as organometallic copolymer) and the method of the present invention for producing the same will be explained in more detail. The organometallic copolymer of the present invention is a crosslinked block copolymer obtained by crosslinking polycarbosilane and polytitanosiloxane by block copolymerization. A typical block copolymer is obtained by bonding each block to each other at each end, and therefore has a structure consisting of a series of blocks connected by head-to-tail bonds. On the other hand, in the organometallic copolymer of the present invention, a part of the silicon atoms of the structural unit (Si-CH ₂ -) existing in the middle of the main chain skeleton of the polycarbosilane moiety is bonded via an oxygen atom. , has a structure in which it is bonded to a part of the silicon atom and/or titanium atom of the structural unit (-Si-O- and/or -Ti-O-) existing in the middle of the main chain skeleton of the polytitanosiloxane moiety. It is something. That is, the organometallic copolymer of the present invention is unique in that the polycarbosilane moiety (A) and the polytitanosiloxane moiety (B) are crosslinked in the middle of the main chain bond, rather than in a head-to-tail bond. It is a crosslinked block copolymer with a unique structure. Although polycarbosilane itself and polytitanosiloxane themselves are known polymers, a copolymer consisting of carbosilane and titanosiloxane has not been known so far. Needless to say, a crosslinked block copolymer in which polycarbosilane and polytitanosiloxane are bonded in the above-mentioned unique bonding manner has never been known, and therefore, the organometallic copolymer of the present invention Coalescence is a new polymer. The fact that the organometallic copolymer of the present invention is a crosslinked block copolymer consisting of a polycarbosilane part and a polytitanosiloxane part shows that it has a gel permeation chromatography (GPC) and an infrared absorption spectrum ( IR). Figure 1 shows the GPC of polycarbosilane obtained by the method of Reference Example 1 described below, and Figure 2 shows the GPC of polytitanosiloxane obtained by the method of Reference Example 2 described later.
GPC, FIG. 3 shows the organometallic compound of the present invention obtained by reacting the above polycarbosilane and polytitanosiloxane at a weight ratio of 1:1 according to the method of Example 1 described later. GPC of the polymer (in each case, a solution of 50 mg of polymer dissolved in 10 ml of tetrahydrofuran was used for the measurement). Moreover, FIG. 4 shows a simple mixture of the above-mentioned polycarbosilane and polytitanosiloxane (weight ratio 1:
1) (the solution used in the measurement was a 50 mg polymer mixture consisting of 25 mg of each polymer dissolved in 10 ml of tetrahydrofuran). GPC of a simple mixture of two polymers shown in Figure 4
matches the superposition of the GPC in Figure 1 and the GPC in Figure 2. However, in the GPC of the copolymer shown in FIG. 3, a new peak that is not seen in any of the GPCs in FIGS. 1, 2, and 4 appears at an elution volume of 8.1 ml on the horizontal axis. This means that the molecular weight has increased due to the block copolymerization of polycarbosilane and polytitanosiloxane (in GPC, the lower the value on the horizontal axis (elution amount) of the peak, the higher the molecular weight is high). Also, if we focus on the peak at an elution volume of 10 ml seen in the GPC of Figures 1 and 2,
In the GPC shown in Figure 3, the height of this peak is extremely small. This means that the content of low molecular weight substances in the block copolymer was significantly reduced. As mentioned above, the GPC experimental results show that the organometallic polymer of the present invention is not a mere mixture of polycarbosilane and polytitanosiloxane, but is a block compound with a high molecular weight due to the combination of the above two types of polymers. This indicates that it is a polymer. Next, to explain the infrared absorption spectra (IR), Fig. 5 shows the IR of the polycarbosilane described in Reference Example 1, Fig. 6 shows the IR of the polytitanosiloxane described in Reference Example 2, and Fig. 7 shows the IR of the polycarbosilane described in Reference Example 1. 1 is an IR of the organometallic copolymer of the present invention described in Example 1. The absorptions at 1250 cm ^-1 and 2100 cm ^-1 in the IR in Figure 5 are absorptions corresponding to Si--CH ₃ and Si--H present in polycarbosilane, the raw material that appears (in Figure 6, the absorption In the IR of siloxane, these absorptions are not present). In the IR of the copolymer shown in Figure 7, the above two absorptions exist, but Si-H absorption intensity (2100 cm ^-1 )/Si-C
Comparing Figures 5 and 7 with respect to the ratio of H ₃ absorption intensity (1250 cm ^-1 ), the ratio is 0.690 in the IR of Figure 5, while it is considerably reduced to 0.568 in Figure 7. ing. This means that
The reaction between polycarbosilane and polytitanosiloxane causes some of the Si--H bonds in polycarbosilane to disappear, thereby producing a block copolymer of polycarbosilane and polytitanosiloxane. It shows. That is, the organometallic copolymer (block copolymer) of the present invention has structural units (-Si-CH ₂ ) present in the main chain skeleton of polycarbosilane.
Some of the hydrogen atoms bonded as side chain groups to the silicon atoms of ) are removed, and the silicon atoms and the structural units (-Si-O- and/or It is produced by crosslinking with a part of the silicon atoms and/or titanium atoms of Ti—O—) through oxygen atoms.
Based on the above IR data, the crosslinking rate of the organometallic copolymer of Example 1 is calculated to be 17.7% (assuming that crosslinking occurs only due to the disappearance of Si--H bonds). The method of the present invention for producing the organometallic copolymer of the present invention comprises heating a mixture of polycarbosilane and polytitanosiloxane in an organic solvent and under an atmosphere inert to the reaction; This is a method in which at least part of the silicon atoms of polycarbosilane is bonded to at least part of the silicon atoms and/or titanium atoms of polytitanosiloxane via oxygen atoms. The organic solvent is used to carry out the reaction smoothly and to suppress the production of by-products such as gel-like substances, and preferred solvents include benzene, toluene, xylene, tetrahydrofuran, and the like. In addition, it is necessary to carry out the reaction in an atmosphere of an inert gas (e.g. nitrogen, argon, hydrogen, etc.), and if it is carried out in an oxidizing atmosphere such as air, This is not preferred because oxidation of silane and polytitanosiloxane occurs. The reaction temperature can be varied over a wide range; for example, it may be heated to a temperature below the boiling point of the organic solvent used, but if a copolymer with a high crosslinking rate is to be obtained, it may be heated to a temperature above the boiling point of the organic solvent. It is preferable to carry out the crosslinking reaction by heating to distill off the organic solvent. The reaction temperature is generally preferably 500°C or lower. The reaction time is not particularly important, but it is usually 1~
It takes about 10 hours. It is generally preferable to carry out the reaction near normal pressure; carrying out the reaction in vacuum or under high reduced pressure is not preferable because low molecular weight components will distill out of the system and the yield will decrease. In order to carry out the method of the present invention, it is preferable to carry out the reaction while feeding an inert gas into the reaction part as a gas stream,
This is because the pressure inside the reactor is thereby maintained at approximately normal pressure, thereby preventing pressure increases due to temperature increases and hydrocarbon gases released during the reaction, such as gases such as methane. In the method of the present invention, the polycarbosilane used as one of the starting materials for producing the organometallic copolymer has a number average molecular weight of about 500 to 10,000.
has a main chain skeleton mainly consisting of structural units of the formula (-Si-CH ₂ )-, in which the silicon atom is substantially a side selected from the group consisting of a hydrogen atom, a lower alkyl group, and a phenyl group. It is a polycarbosilane having two chain groups. In addition to the above-mentioned side chain groups, an OH group may be bonded to the silicon atom of the terminal group of polycarbosilane. The method for producing polycarbosilane itself is well known;
The above polycarbosilane used as a starting material in the present invention can be produced by such known methods. For example, Fritz; Angew. Chem. 79 p. 657 (1967) discloses a method for producing polycarbosilane by directly polymerizing monosilane; A method for producing polycarbosilane by the above method is disclosed in Japanese Patent Publication No. 57-26527 and Japanese Patent Application Laid-open No. 52-1989 filed by the present applicant.
No. 74000 and JP-A-52-112700. Among the polycarbosilanes used in the present invention, polycarbosilanes whose main chain skeleton consists essentially only of (-Si-CH ₂ )- structural units can be produced by the above-mentioned known method. . Polycarbosilanes particularly suitable for use as starting materials in the present invention include modified polycarbosilanes prepared by the method described in JP-A-54-61299 filed by the applicant; That is, it is a polycarbosilane partially containing siloxane bonds. This modified polycarbosilane mainly consists of the following structural units (A) and (B), (A):

[Formula] (B):

[Formula] (Here, R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a lower alkyl group or a phenyl group) The ratio of (A) and (B) is 5:1 to 200: 1, and is a polycarbosilane partially containing siloxane bonds with a number average molecular weight of 500 to 10,000. This modified polycarbosilane is

For polysilanes having the structure [formula] (where n≧3, R ₁ and R ₂ have the same meanings as above), the skeleton components are B, Si and O
0.01 to 15% by weight of polyborosiloxane having a phenyl group in at least a part of the Si side chain.
The mixture of polymers is heated at 250°C or higher under an atmosphere inert to the reaction.
It can be produced by heating preferably at 300 to 500°C and polymerizing usually for 8 to 10 hours. In the method of the present invention, the polytitanosiloxane used as another starting material for producing the organometallic copolymer has a number average molecular weight of about 500 to 10,000.
has a main chain skeleton consisting of titanoxane bonding units (-Ti-O)- and siloxane bonding units (Si-O)-, and the ratio of the total number of titanoxane bonding units to the total number of siloxane bonding units is 30:1. 1:30, most of the silicon atoms of the siloxane bonding unit have one or two side chain groups selected from the group consisting of lower alkyl groups and phenyl groups, and the titanoxane Most of the titanium atoms in the bonding units are polytitanosiloxanes having one or two lower alkoxy groups as side chain groups. In addition to the above-mentioned side chain groups, an OH group may be bonded to the silicon atom or titanium atom that exists as a terminal group of polytitanosiloxane. The production of polytitanosiloxane itself is known, and the above-mentioned polytitanosiloxane used as a starting material in the present invention can be produced by such a known synthesis method. Typical synthesis methods include (a) a synthesis method by cohydrolysis of organochlorosilane and titanium alkoxide, (b) a synthesis method by dehydrochloric acid condensation reaction of organosilanol and titanium chloride, or (c) a synthesis method using organosilanol and titanium chloride. A synthesis method using a dealcoholization condensation reaction of an alkoxide can be mentioned. When synthesizing the polytitanosiloxane used in the present invention by the synthesis methods (a) to (c) above, -Si-
The formation of the O--Ti--O- bond is expressed as follows.

[Table] Synthesis methods for polytitanosiloxane include, for example,
Inorganic Polymers (FGAStone, Academic
Press. 1962), and also in the specification of Japanese Patent Application No. 58004/1983 filed by the applicant. The polytitanosiloxane used as a starting material in the present invention has a number average molecular weight of 500 to 10,000, and has an organic solvent such as benzene, toluene, xylene,
It is a polymer soluble in acetone, tetrahydrofuran, etc.). In this specification, the siloxane bonding unit present in the main chain skeleton is expressed by the simplified formula -(Si-O)- according to the conventional writing method, but as is well known to those skilled in the art,
The siloxane bonding unit represented by the above formula is a difunctional group.

[Formula] Trifunctional group

[Formula] and tetrafunctional group

It contains three types of siloxane bonding units: [Formula] (R in the formula is a side chain organic group). All of these three types of siloxane bonding units can serve as structural units forming the main chain skeleton of the polytitanosiloxane used in the present invention.
However, as the content of tetrafunctional siloxane bonding units increases, the polymer generally becomes rich in crosslinked structures and becomes insoluble in organic solvents. It is necessary that the majority be di- or tri-functional siloxane bonding units and only a small amount of tetra-functional siloxane units. Therefore, the polytitanosiloxane used as a starting material in the present invention has a siloxane bonding unit (-
Most of the silicon atoms of Si-OZ- should be bonded to one or two side chain organic groups R (lower alkyl or phenyl groups). That is, the polytitanosiloxane used in the present invention may contain a small amount of tetrafunctional siloxane bonding units, but the content must be within a limit that does not inhibit the solubility of the polymer in organic solvents. The polytitanosiloxane bonding units used in the present invention preferably consist essentially of difunctional and/or trifunctional siloxane bonding units. Similarly to the above, the titanoxane bonding unit represented by the formula (-Ti-O)- can also be a difunctional group, a trifunctional group,
Although it contains a tetrafunctional group, for the same reason as stated above, most of the titanoxane bonds in the polytitanosiloxane used in the present invention have two side chain organic groups (lower alkoxy groups). (a difunctional group) or one (a trifunctional group), and the titanoxane bonding unit is substantially difunctional and/or has one (trifunctional group).
Or a trifunctional titanoxane bonding unit is preferred. In the polytitanosiloxane used in the present invention, the ratio of the total number of titanoxane bonds to the total number of siloxane bonds is within the range of 30:1 to 1:30. The polytitanosiloxane used in the present invention is a polymer consisting of a skeleton in which the above-mentioned siloxane bonds (-Si-O-) and titanoxane bonds (-Ti-O-) are randomly bonded. It can take various structures such as annular, ladder-like, cage-like, or mesh-like. In the method of the present invention, the above-mentioned polycarbosilane and polytitanosiloxane are bonded to the total number of (-Si-CH ₂ -) structural units of the polycarbosilane to the (-Ti-O-) bond of the polytitanosiloxane. Unit and (-Si-O
-) Mix in a quantitative ratio such that the ratio of the total number of bonding units is within the range of 100:1 to 1:100, and the resulting mixture is reacted, thereby forming a crosslink between the two polymers. As explained earlier, the crosslinking reaction mainly involves the elimination of hydrogen atoms bonded as side chain groups among the silicon atoms of the structural unit (-Si-CH ₂ -) in the main chain skeleton of polycarbosilane. The separated silicon atom is a part of the silicon atom and/or titanium atom of the siloxane bond unit and/or titanoxane bond unit in the main chain skeleton of polytitanosiloxane,
This reaction involves bonding via oxygen, and thus the organometallic polymer of the present invention, which is a crosslinked block copolymer, is the main constituent. Therefore, when focusing on the polycarbosilane moiety of the block copolymer, the silicon atoms in the main chain skeleton involved in crosslinking had two side chain groups before the crosslinking reaction, but After the reaction, the silicon atoms in the main chain skeleton that have one side chain group and do not participate in crosslinking are substantially 2 atoms selected from hydrogen atoms, lower alkyl groups, and phenyl groups. It has 3 side chain groups. The organometallic polymer of the present invention produced by the method described above is a block copolymer with a molecular weight of 1,000 to 50,000, in which the polygarbosilane and polytitanosiloxane specified in the present invention are crosslinked. It is a thermoplastic substance that melts when heated at 50 to 400°C, and is a solvent such as benzene, toluene, xylene, and tetrahydrofuran. FIG. 7 shows the infrared absorption spectrum (IR) of the organometallic copolymer of the present invention obtained by the method of Example 1. It is a block copolymer consisting of a polycarbosilane partially containing siloxane bonds obtained from silane and polyborodiphenylsiloxane, and polytitanosiloxane obtained from diphenylsilanediol and titanium tetrabutoxide. The starting materials (polycarbosilane and polytitanosiloxane) shown in Figures 5 and 6
Taking IR into consideration, the assignment of IR to the block copolymer shown in FIG. 7 is determined as follows. Si-C ₆ H ₅ around 500cm ^-1 and 700cm ^-1 ; Si-CH ₃ around 800cm ^-1 and 1250cm ^-1 : Si-O-Ti at 920cm ^-1 ;
1020~1030cm ^-1 Si―CH ₂ -Si: 1050cm ^-1 , 1120
cm ^-1 Si-O; 1430 cm ^-1 Si-C ₆ H ₅ ; 2100 cm ^-1
Si—H; C in Ti—OC ₄ H ₉ from 2850 to 2940 cm ^-1
-H; C-H at 2900 cm ^-1 and 2950 cm ^-1 ; Absorption corresponding to each C-H bond at C ₆ H ⁵ near 3050 cm ^-1 is shown in the IR in FIG. As explained above, the organometallic copolymer of the present invention is a crosslinked block polymer with a novel structure;
When fired in an inert gas atmosphere or a non-oxidizing gas atmosphere, this copolymer has superior mechanical strength compared to conventional SiC and superior oxidation resistance at high temperatures compared to conventional TiC. Mainly TiC, SiC, solid solutions of TiC and SiC, and TiC _1-x
(However, 0<x<1) can be converted into a composite carbide. In addition, since it melts when heated and is soluble in organic solvents, it can be molded into various shapes. By heating and firing, it is possible to obtain a composite carbide compact having the above-mentioned structure and having extremely excellent performance. Examples of such molded bodies include continuous fibers, films, coatings, powders, etc. mainly made of this composite carbide. In addition to the above-mentioned composite carbide products, the organometallic copolymer of the present invention can also be used as a binder for sintering or as an impregnating agent.Furthermore, since it has excellent heat resistance, it can be used in various applications even as a polymer. It is expected that the The present invention will be explained below with reference to Examples. Reference Example 1 Put 2.5 g of anhydrous xylene and 400 g of sodium into a three-necked flask and heat it under a nitrogen gas stream to the boiling point of xylene.
was added dropwise over 1 hour. After the dropwise addition was completed, the mixture was heated under reflux for 10 hours to form a precipitate. After this precipitation,
First, the mixture was washed with methanol and then with water to obtain 420 g of white powder polydimethylsilane. On the other hand, 759 g of diphenyldichlorosilane and 124 g of boric acid are heated at a temperature of 100 to 120°C in n-butyl ether under a nitrogen gas atmosphere, and the resulting white resinous material is further heated at 400°C in vacuum for 1 hour. This yielded 530 g of polyborodiphenylsiloxane. Next, 0.125 g of the above polyborodiphenylsiloxane was added and mixed to 250 g of the above polydimethylsilane, and the mixture was heated to 350°C under a nitrogen stream in a quartz tube equipped with a reflux tube for 3 hours to polymerize. , a polycarbosilane to be used as a raw material for the copolymer of the present invention was obtained. After cooling at room temperature, xylene was added to take out the solution, xylene was evaporated, and the mixture was concentrated to 300° C. under a nitrogen stream to obtain 84 g of solid. The number average molecular weight of this polymer was determined by vapor pressure osmosis (VPO).
It was 1500 when measured by the method). When we measured the IR spectrum of this material, as shown in Figure 5, we found Si-CH ₃ absorption near 800 cm ^-1 and 1250 cm ^-1 , C-H absorption at 1400, 2900, and 2950 cm ^-1 , and C-H absorption at 2100 cm -1.
Si-H absorption at cm ^-1 , Si-CH ₂ at 1020, 1350 cm ^-1
-Si absorption, Si-O absorption near 1050cm ^-1 ,
Absorption of Si-C ₆ H ₅ was observed at 700, 1120, and 1430 cm ^-1 , and the resulting polymer showed that the constituent elements were

【formula】 【formula】

【formula】

【formula】

It is a polycarbosilane with the formula: Reference Example 2 864 g of diphenylsilanediol and 340 g of titanium tetrabutoxide were weighed out, xylene was added thereto, and a reflux reaction was carried out at 150° C. for 1 hour under nitrogen gas. After the reaction was completed, the insoluble matter was filtered off, and the solvent xylene was removed using an evaporator, and the resulting intermediate product was further polymerized by heating at 300°C for 1 hour under nitrogen gas to be used as a raw material for the copolymer of the present invention. Using the polytitanosiloxane used, a polymer was obtained in which the ratio of the total number of titanoxane bonds to the total number of siloxane bonds was 1:4. The number average molecular weight was 1600 by the VPO method. When we measured the infrared absorption spectrum of this material, it was ~3600 cm ^-1 as shown in Figure 6.
Slight absorption of Si-OH near 2900cm ^-1
Absorption of C ₄ H ₉ , 1600 cm ^-1 Absorption of benzene nuclei near 1400 cm ^-1 , absorption of Si-O at 1150 to 1000 cm ^-1 , 900 cm
Absorption of Ti-O in the Ti-O-Si bond was observed near ^-1 , and the resulting polymer had a skeleton of Ti, Si, and O, with a phenyl group in the Si side chain and a butoxy group in the Ti side chain. It is a polymer having groups. Example 1 40g of polycarbosilane obtained in Reference Example 1,
Weigh out 40 g of the polytitanosiloxane obtained in Reference Example 2, add 400 ml of xylene to this mixture to make a mixed solution consisting of a homogeneous phase, and perform a reflux reaction under nitrogen gas atmosphere at 130°C while stirring for an hour. Ta.
After the reflux reaction was completed, the temperature was further raised to 200℃ to distill off the solvent xylene, and then the temperature was raised to 200℃.
Polymerization was carried out for 2 hours to obtain an organometallic copolymer. The number average molecular weight of this polymer was determined to be 3550 by the VPO method. The results of gel permeation chromatography of this material shown in FIG. 3, and the polycarbosilane of Reference Example 1 shown in FIG.
As is clear from the comparison of gel permeation chromatography results obtained by simply mixing the polycarbosilane and polytitanosiloxane of Reference Example 2, the polymer obtained here is a mixture of the polycarbosilane and polytitanosiloxane described above. It is not a mixture, but a copolymer in which both of the raw material polymers react and have a high molecular weight. Also, the IR of this substance shown in Figure 7
As is clear from the comparison between the spectrum and the IR spectra of polycarbosilane and polytitanosiloxane shown in Figures 5 and 6, the polymer obtained here has a polycarbosilane moiety and polytitanosiloxane. The Si--H bond in the polycarbosilane part disappears, and this part becomes the silicon atom and/or the polytitanosiloxane part.
Alternatively, it is a copolymer in which a polycarbosilane portion and a polytitanosiloxane portion are crosslinked by bonding to at least a portion of titanium atoms via an oxygen atom. -Si-CH ₂ - of polycarbosilane part
total number of bonds vs. polytitanosiloxane moiety)—Ti
-O-) The ratio of the total number of bonds is 7:2. The copolymer obtained here was heated in a nitrogen atmosphere.
The mixture was heated to 1700°C for 8.5 hours and calcined at 1700°C for 1 hour to obtain a black solid. When X-ray powder diffraction measurements were performed on this substance, as shown in Figure 8,
(111) diffraction line of β-SiC at 2θ=35.8°, 2θ=
(220) diffraction line of β-SiC at 60.1° and 2θ=
There is a (311) diffraction line of β-SiC at 72.1°, and 2θ=
(200) diffraction line of TiC at A2.4°, 2θ=36.4°
A (111) diffraction line of TiC, a (220) diffraction line of TiC at 2θ = 61.4°, and a (113) diffraction line of TiC at 2θ = 73.5° were observed. In particular, each diffraction line of PiC is two times smaller than each diffraction line observed for conventional TiC.
It is shifted to a higher angle than θ, which is different from conventional TiC.
Since the lattice constant is different from
It is estimated to be a composite carbide mainly consisting of β-SiC, TiC, a solid solution of β-SiC and TiC, and TiC _1-x (0<x<1). Example 2 The present invention was carried out in the same manner as in Reference Example 2, except that 600 g of diphenylsilanediol and 394 g of titanium tetrainopropoxide were weighed, xylene was added thereto, the solvent was removed, and the reaction was carried out at 250°C for 30 minutes. The number average molecular weight used as the raw material for the copolymer is
960, a polytitanosiloxane in which the ratio of the total number of titanoxane bonds to the total number of siloxane bonds was 1:2 was obtained. Weigh out 80 g of this polymer and 40 g of polycarbosilane obtained in Reference Example 1, add 500 ml of xylene to this mixture to make a mixed solution consisting of a homogeneous phase, and reflux with stirring at 130°C for 2 hours under a nitrogen gas atmosphere. The reaction was carried out. After the reflux reaction was completed, the temperature was further raised to 200°C to distill off the xylene solvent, and then polymerization was carried out at 200°C for 2 hours to obtain an organometallic copolymer with a number average molecular weight of 5,700. The total number of -Si-CH ₂ - bonds in the polycarbosilane portion of this polymer versus (-Ti-O
The ratio of the total number of -) bonds and (-Si-O) bonds is approximately 7:
It is 4. Example 3 72g of polycarbosilane synthesized in Reference Example 1,
Weigh out 8 g of polytitanosiloxane synthesized in Reference Example 2, add 400 ml of benzene to this mixture to make a mixed solution consisting of a homogeneous phase, and heat at 70°C under a nitrogen atmosphere.
The reflux reaction was carried out while stirring for 5 hours. After the reflux reaction is completed, further heating is performed to distill off benzene.
Polymerization was performed at 250℃ for 1 hour, and the number average molecular weight was 8200.
An organometallic copolymer was obtained. The obtained polymer was a uniform transparent resinous material. The ratio of the total number of -Si-CH ₂ - bonds in the polycarbosilane part of this resin-like material to the total number of (-Ti-O-) bonds and (-Si-O-) bonds in the polytitanosiloxane part is approximately 31. :1.

[Brief explanation of the drawing]

Figure 1 shows gel permeation chromatography (GPC) of the polycarbosilane of Reference Example 1, and Figure 2 shows the gel permeation chromatography of the polytitanosiloxane of Reference Example 2.
GPC, Figure 3 shows the GPC of the organometallic copolymer of the present invention in Example 1, and Figure 4 shows the GPC of the polycarbosilane of Reference Example 1 and the polytitanosiloxane of Reference Example 2 in a weight ratio of 1:1. It is GPC. Figure 5 shows the infrared absorption spectrum (IR) of the polycarbosilane of Reference Example 1, Figure 6 shows the IR of the polytitanosiloxane of Reference Example 2, and Figure 7 shows the organometallic copolymer of the present invention in Example 1. This is a combined IR. FIG. 8 is an X-ray powder diffraction diagram of a composite carbide obtained by firing the organometallic copolymer of the present invention of Example 1 at 1700° C. in a nitrogen atmosphere.

Claims (1)

[Claims] 1. Has a main chain skeleton mainly composed of structural units of the formula (-Si-CH ₂ -) with a number average molecular weight of approximately 500 to 10,000, in which the silicon atoms are substantially hydrogen atoms. , a polycarbosilane having two side chain groups selected from the group consisting of a lower alkyl group and a phenyl group, and 2 a titanoxane bonding unit (-Ti-O-) and a siloxane bond having a number average molecular weight of about 500 to 10,000. It has a main chain skeleton in which units (-Si-O)- are randomly bonded, and the ratio of the total number of titanoxane bonding units to the total number of siloxane bonding units is 30:1 to 1:30.
most of the silicon atoms in the siloxane bonding unit have one or two side chain groups selected from the group consisting of lower alkyl groups and phenyl groups, and the titanium atoms in the titanoxane bonding unit A polytitanosiloxane, most of which has one or two lower alkoxy groups as side chain groups, is combined with the total number of (-Si-CH ₂ -) structural units of the polycarbosilane versus the -( of the polytitanosiloxane). The ratio of the total number of Ti-O)- bond units and (-Si-O-) bond units is 100:
The resulting mixture is heated in an organic solvent in an atmosphere inert to the reaction to reduce the amount of silicon atoms in the polycarbosilane. A crosslinked polycarbosilane moiety and a polytitanosiloxane moiety, characterized in that one part of each is bonded to at least one part of silicon atoms and/or titanium atoms of the polytitanosiloxane via oxygen atoms. A method for producing an organometallic crosslinked block copolymer having a number average molecular weight of about 1,000 to 50,000.