AU618233B2 - Derivatized alkylpolysilane preceramic polymers - Google Patents

Description

4. The basic application referred to in paragraph 2, of this Declaration was the first application made in a Convention country in re,..tect of the invention the subject of the application.

DECLARED at Xi d41uid,tAs!. gan U. this L~v r" COMMONWEALTH OF AUSTRALI 1 83m1% PATENTS ACT 1952-69 6 1 &a3 COMP-1 RL-ETE

(ORIGINAL)

class Int. Class Application Number: Lodged: Complete Specification Lodged-, Accepted: Published: Priority: Related Art: Name of Applizant; Address of Applicant: Actual Inventor: Address for Service: DOW CORNING CORPORATION Midland, State of Michig~kn United StaLas of America Duane Ray Bujaiski, Gary Edward Legrou and Thomas Fay-Oy Limn EDWD. WATERS SONS, 50 QUEEN ST~REET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention enlitled: DERIVIATIZED ALKYLPOLYSILANE PRECERAMIC POLYMERS The following statement Is a full description of this Invention, Including the best method. of performing It known to -U S la DERIVATIZED ALKYLPOLYSILANE PRECERAMIC POLYMERS The United States Government has rights in this invention pursuant to Contract Number F33615-83-C-5006 awarded by the United States Air Force.

This invention relates to derivatized alkylpolysilanes, and especially derivatized methylpolysilanes, which are useful as preceramic polymers in the preparation of ceramic materials and articles. This invention further relates to the methods of preparing such derivatized alkyl- D° polysilanes and derivatized methylpolysilanes as well as the ceramics prepared from such preceramic polymers.

Baney et al. in U.S. Patent 4,310,651 (issued January 12, 1982) disclosed a polysilane of general formula

(CH

3 Si)((CH 3 where there was present 0 to 60 mole percent ((CH 3 2 Si) units and 40 to 100 mole percent (CH 3 Si) "o units and where the remaining bonds on silicon were attached b to other silicon atoms and chlorine atoms or bromine atoms.

Of The polyilane was converted to a beta-silicon carbide S containing ceramic material at elevated temperatures (about o2P 1400OC). The polysilanes of U.S. Patent 4,310,651 generally o o are difficult to handle due to th-eir high reactivity in air.

Baney et al. in U.S. Patent 4,298,559 (issued November 3, 1981) prepared polysilanes of general formula

(CH

3 Si)((CH 3 where there was present 0 to 60 mole percent ((CH 3 2 Si) units and 40 to 100 mole percent (CH 3 Si) units and where the remaining bonds on silicon were attached to other silicon atoms and additional alkyl radicals of 1 to 4 carbon atoms or phenyl radicals. Upon heating, these polysilanes are converted into silicon carbide-containing ceramics in high yields, 1.

~:i:i't

A

-2- 0440 4 40 4 4 4b 4 44 r *e 64 4 64 o Q 4*S #6 44 4~ 66 Baney in U.S. Patent 4,310,481 (issued January 12, 1982) disclosed polysilanes of the general formula

(CH

3 Si)((CH 3 2 Si) where there was present 0 to 60 mole percent 2 Si) units and 40 to 100 mole percent (CH 3 Si) units and where the remaining bonds on silicon were attached to silicon and (CH 3 3 SiO- radicals. A silicon carbide containing ceramic was obtained by firing this polysilane to an elevated temperature under an inert atmosphere vacuum.

Baney in U.S. Patent 4,310,482 (issued January 12, 1982) disclosed polysilanes of the general formula (CH3Si)((CH 3 where there was present 0 to 60 mole percent ((CH 3 )2Si) units and 40 to 100 mole percent (CHASi) units and where the remaining bonds on silicon were attached to silicon and hydrogen. A silicon carbide containing ceramic was obtained by firing this polysilane to an elevated temperature under an inert atmosphere or vacuum.

Baney et al. in U.S. Patent 4,314,956 (issued February 9, 1982) disclosed polysilanes of the general formula (CH 3 Si)((CH 3 where there was present 0 to mole percent ((CH 3 units and 40 to 100 mole percent (CH3Si) units and where the remaining bonds on silicon were attached to silicon and amine radicals of the general formula -NHR'' where is a hydrogen atom, an alkyl radical of 1 to 4 carbon atoms or a phenyl radical. A silicon carbide containing ceramic was obtained by firing this polysilane to an elevated temperature under an inert atmosphere or under an ammonia atmosphere.

Baney et al. in U.S. Reissue Patent Re. 31,447 (reissued November 22, 1983) disclosed polysilanes of the general formula (CH 3 Si)((CH, 3 )Si) where there was present 0 to 60 mole percent ((CH 3 )2Si) units and 40 to 100 mole percent (CH 3 Si) units nnd where the remaining bonds on silicon were attached to other silicon atoms and alkoxy -3radicals containing 1 to 4 carbon atoms or phenoxy radicals.

Silicon carbide containing ceramics were obtained by firing these polysilanes to elevated temperatures.

These polysilanes are further discu i in Baney et al., Organometallics, 2, 859 (1983).

What has been newly discovered are derivatized alkylpolysilanes of general formula .RzSi)(RSi)(R'Si) wherein each R is independently selected from alkyl radicals containg 1 to 4 carbon atoms, where each R' is independently selected from the group consisting of alkyl t radicals of at least aix carbon atoms, phenyl radicals, and radicals of the formula A y( ySi(CH 2 wherein each A is S independently selected from a hydrogen atom or alkyl radicals 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 S or equal to 1, where there are from 0 to 40 mole percent

(R

2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole ;c percent (R'Si) units, and where there are also bonded to the e ce silicon atoms other silicon atoms and radicals selected from the group consisting of hydrogen atoms, additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, allyl radicals, phenyl radicals, (CH 3 3 SiO-radicals, radicals, and -N(RV) 2 radicals where is an alkyl radical v Sof 1 to 4 carbon atoms or a phenyl radical and R is hydrogen, an alkyl radical of to 4 carbon atoms, a phenyl radical, or a -SiA', radical where each A' is independently selected from alkyl radicals containing 1 to 4 carbon atoms, hydrogen or vinyl. These derivatized alkylpolysilane preceramic polymers can be pyrolyzed at elevated temperatures under an inert atmosphere to yield ceramic materials or articles. These derivatized alkylpolysilanes represent a significant advance in the art of preparing ceramic materials -4or articles, especially in the art of preparing ceramic fibers.

This invention relates to derivatized alkylpolysilanes of the average formula (R 2 Si)(RSi)(R'Si) wherein each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms, wherein each R' is independently selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula AyXX Si(CH) where each A is independently selected from S, a hydrogen atom or alkyl radicals 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, where there are from 0 to 40 mole percent (R 2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and radicals selected from the group consisting of hydrogen atoms, additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, allyl radicals, phenyl Sradicals, (CH 3 ),SiO-radicals, radicals, and -N(R )2 radicals where each R" is independently selected from alkyl radicals of 1 to 4 carbon atoms or a phenyl radical and R is hydrogen, an alkyl radical of 1 to 4 carbon atoms, a phenyl radical, or a -SiA", radical where each A' is independently selected from alkyl radicals containing 1 to 4 carbon atoms, rc hydrogen or vinyl.

The non-derivatized alkylpolysilanes useful in this invention to prepare the inventive derivatized alkylpolysilanes are described by the average formula

(R

2 Si)(RSi)(R'Si) where each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms and each R' is independently selected from the group consisting of alkyl rad.c4ls of at least six carbon atoms, phenyl radicals, and radicals of the formula AX. _ySi(CH2) z where each A is independently selected from a hydrogen atom or alkyl radicals 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, and there are from 0 to 40 mole percent (R 2

S')

units, 1 to 99 mole percent (RSi) units, and 1 to 99 mole percent (R'Si) units and wherein the remaining bonds on silicon are attached to either other silicon atoms, chlorine atoms or bromine atoms. These are chlorine- or brominecontaining polysilanes where the remaining bonds on silicon are attached to other silicon atoms and chlorine atons or bromine atoms. Preferably, these polysilanes contain from 0 to 40 mole percent (R 2 Si) units, 40 to 99 mole percent (RSi) units, and 1 to 30 mole percent (R'Si) units. Most preferably, these polysilanes contain from 0 to 10 mole S percent (R 2 Si) units, 80 to 99 mole percent (RSi) units, and 1 to 20 mole percent (R'Si) units. The chlorine-containing polysilanes are preferred in the practice of this invention.

"o The non-derivatized polysilanes may be prepared by 8 0> AU PctervJ p\ \cq4f\onA (S,/9i oo the method described in at nApicatn a N©.945,126 entitled "Felyailan Fin zeeeremle -Pelymflera" in the 0 nmes of Du-na meay -Bujalki, Gary Edwa-rd LmGrow and Thmaasa-Fay ey Which was -fi-ld on the-ante date asm tfhi-s SappleattHm. In general, these polysilanes may be prepared by reacting a mixture of about 40-99 weight percent of one or Smore chlorine-containing or brominie-containing disilanes and 1 to 60 weight percent of one or more monoorganosilanes of the formula R'SiX 3 where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A X( _y Si(CH;) where each A is :independently selected from a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an integer equal. to 0 to 3, X is chlorine or bromine, and z is at integer greater than or equal to 1, with -6- 0.001 to 10 weight percent of a rearrangement catalyst at a temperature of 100 0 C to 340 0 C while distilling by-produced volatile materials. More preferably, these polysilanes are prepared by reacting a mixture of about 70-99 weight percent of one or more chlorine-containing or bromine-containing disilanes and 1 to 30 weight percent of one or more monoorganosilanes of formula R'SiX 3 where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula AX (_)Si(CH2) z where each A is independently selected from off a hydrogen atom or alkyl radicals containing 1 to 4 carbon S' 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, with S 0.001 to 10 weight percent of a rearrangement catalyst at a temperature of 100 0 C to 3409C while distilling by-produced volatile materials.

The chlorine-containing or bromine-containing disilanes used to prepare the non-derivatized polysil,'nes are Sof the general formula (RbXcSi)2 wherein each R is independently selected from alkyl radicals containing from 1 L to 4 carbon atonm, b has a value of 0 to 2.5, c has a value of 0.5 to 3, the sum equals three, and X is chlorine or a 4 bromine. R in the above disilane may be phenyl, methyl, ethyl, propyl or butyl. Examples of such disilanes include CHC12SiSiCl(CH3 Ch3Cl2SiSiCI2CH3, CH3Br2SiSiBr(CI3)2, CH3Br 2 SiSiBr 2 CH,, and the like. Preferably in the above disilane, R is a methyl radical and X is chlorine. The didilane can be prepared from the appropriate silanes or the disilane can be utilized as it is found as a component of the process residue from the direct synthesis of organochlorosilanes. The direct synthesis of organochlorosilanes involves passing the vapor of an organic chloride over heated silicon and a catalyst. See Eaborn, "Organosilicon -7- CoMpounds," Butterworths Scientific Publications, 1960, page 1 The disilanes Ca 3 ,Cl 2 SiSiCl 2

CH

3 and (CH,) 2 ClSiSiCl 2

CH

3 are found in large quantities in the residue from the reaction and, therefore, this Direct Process residue is a good starting material for obtai4ning the non-derivatized polysilane polymers uzed in this invention.I The minoorganosilanes used to prepare the nonderivatized polysilanes are of formula R'SiX 3 where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the ~~'frrmula A yX (3-y)Si(CH 2 where each A is independently SselectCed from a hydrogen atom or alkyl radicals containing 1 0%to 4 carbon atoms, y is an integer equal to 0 to 3, X is 0chlorine or bromine, and z is an integer greater than or 0 0equal to 1. The A radicals in the formula A X Si(H may be the same or different, Generally, the monoorganosilane shol Id have a boiling point of about 180'C or greater at one atmoophere. Examples of suitable monoorganosilanes 0 ,include phenyltrichiorosilane, n-hexyltrichlorosilatie, n-octyltrichlorosi lane, pheny),tribromosi lane, n-octyltribromosilane, C1 3

S.'H

2 CH.z~iC1 3 CHCl 2 SiCH2C{ 2 SiCI 3

(CH

3 2 ClSiCHIHZSiC, 3 H(CH-L),SCHCH.SiC1 3 and the like.

Phenyltrichlorosilane and n-octyitrichlorosilane are the Spreferr~d tonoorganosilanes, Mixtures of such monoorganosilanes may also be used. Indeed, mixtures of monoorganosilanes are generally preferred in the practice of this inventimn. One especially preferred mixture of monoorganosilanes contains n-octyltrichlorosilane and phenyltrichlorosilane, The use of such monoorganosilanes, either singly or in mixtures, uppears to allow for control of both the softening or glass transition temperatures of the derivatized polysilanes and the relative silicon. arid carbon content of the ceramic materials produced -8from the derivatized alkylpolysilanes by a variation of the (R'Si) content in the non-derivatized alkylpolysilanes. In general, it appears that increasing the (R'Si) content of the non-derivatized, and thus the derivatized, alkylpolysilanes results in a reduction in the glass transition temperature.

Incorporation of (n-octyl-Si) units allows for a significant reduction of the glass transition temperature with the amount oC the reduction being dependent on the level of units in the alkylpolysilane. Incorporation of (phenyl-Si) units also results in a decrease in the glass transition temperature but the observed effect is generally less than ~O for incorporation of (n-octyl-Si) units. Upon pyrolysis of 4 70 the derivatized alkylpolysilanes containing (n-octyl-Si) units, it appears that the n-octyl group is lost from the o ceramic material as an olefin thereby leaving the ceramic material Jarbon deficient relative to ceramic materials prepared from similar polymers without (n-octyl-Si) units. It P. is expected that other alkyl groups containing at least six 00o carbon atoms will behave in a similar manner. Phenyl groups are generally not lost upon pyrolysis. Therefore, pyrolysis a of the derivatized alkylpolyslanes containing (phenyl-Si) units allows more carbon to be incorporated into the final ceramic material and therefore produces ceramic materials Sa that are carbon rich relative to ceramic materials prepared from similar polymers without (phenyl-Si) units. Thus, by incorporation of (R'Si) units where R' is n-octyl and phenyl, the relative silicon and carbon content of the resulting ceramic materials can be controlled to a large extent. It is possible by the practice of this invention to prepare ceramic materials containing SiC with either excess carbon or excess silicon as well as stoichiometric amounts of silicon and carbon, Methyl raidicals in the form of (CHSi) or ((CHa) 2 Si) units are generally not lost on pyrolysis, Therefore, the i I 0 -9relative amounts of silicon and carbon will also depend in part on the presence of the other units in the derivatized alkylpolysilane but the incorporation of (n-octyl-Si) and (phenyl-Si) units can be used to "fine tune" the relative silicon and carbon content of the ceramics.

The disilane and monoorganosilane mixtures are reacted in the presence of a rearrangement catalyst.

Suitable rearrangement catalysts include ammonium halides, tertiary organic amines, quaternary ammonium halides, o-0 quaternary phosphonium halides, hexamethylphosphoramide, and silver cyanide. Preferred catalyst includes quaternary SO" ammonium halides having the formula W 4 NX', quaternary Sphosphonium halides having the formula W 4 PX', and hexamethylo, phosphoramide where W is an alkyl or aryl radical and X" is o o halogen. Preferably, W is an alkyl radical containing 1 to 6 carbon atoms or a phenyl radical and X* is chlorine or bromine. One especially preferred catalyst is tetra-n- So butylphosphonium bromide.

o o n The amount of catalyst utilized can range from 0,001 to 10 weight percent and preferably from 0.1 to weight percent based on the weight of the starting disilane/monoorganosilanti mixture, The catalysts and starting materials require anhydrous conditions and therefore 2 one must take care to insure that moisture is excluded from the reaction system when the reactants are mixed, Generally, this can be done by using a stream of dry nitrogen or argon as a cover over the reaction mixture.

The mixture of about 40 to 99 weight percent disilane or disilanes and 1 to 60 Weight percent monoorganosilane or monoorganosilanes is reacted in the presence of 0.001 to 10 weight percent: of a rearrangement catalyst at a temperature of 100°C to 340 C while distilling by-produced volatile materials until there is produced the chlorine-

I

containing or bromine-containing polysilane. Preferably the reaction mixture contains 70 to 99 weight percent disilane or disilanes and 1 to 30 weight percent monoorganosilane or monoorganosilanes. Most preferably, the reaction mixture contains 80 to 98 weight percent disilane or disilanes and 2 to 20 weight percent monoorganosilane or monoorganosilanes, The order of mixing the reactants is not critical, Preferably, the reaction temperature is from 150 0 C to 300 0

C.

When the final reaction temperature is higher than the boiling point of the monoorganosilane, it is preferred that the reaction temperature be raised slowly to the final temperature so that the monoorganosilane will have a greater tendancy to incorporate into the polyme7 as opposed to simply distilling out of the reaction mixture. Increasing the incorporation of the monoorganosilane ray also be accomplished by removing the volatile by-products only in the later stages of the reaction, Typ'"ally the reaction is carried out for about 1 to 48 hours although other 'ime Sdurations may be employed.

The chlorine or bromine atoms in the chlorine- or bromine-containing non-derivatized alkylpolysilanes are very reactive. This reactivity makes the handling of these alkylpolysilanes difficult. These alkylpolysilanes are especially difficult to handle when a low oxygen containing ceramic S material is desired, Therefore, it is preferred that the chlorine or bromine atoms be replaced with less reactive groups By the practice of this invention, the highly reactive chlorine or bromine atoms of the chlorine- or bromine-containing alkylpolysilanes may be replaced by the generally less reactive radicals selected from the group consisting of hydrogen atoms, additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, allyl radicals, phenyl radicals, (CH)3SiO-radicals, radicals, and -(e2radicals wherte is an alkyl radical of 1 to 4 carbon atoms or a phenyl radical and RV is hydrogen, an alkyl, radical of 1 to 4 cairbon atoms, a phenyl radical, or a -SiA' 3 radical where each A' is independently selected from al'kyl radicals containing 1 to 4 carbon atoms hydrogen or vinyl thereby forming the derivatized allrylpolysilane preceramic polymers of this invention, The derivatized al~cylpolysilanes containing additional alkyl, vinyl, allyl, or phenyl groups can be prepared using the general tech~niques of TY..S, Patent No, %.~4,298,559, Such derivatized alk-yl polysi lanes can be prepared by reacting the non-ervaid aypoyines of this Sinvention with an alkyl, vir~xyl, ally!, or phenyl Grignard 000 v reagent of general formula R MgX or with an organolithium compound of generAl formula Fiv Li Where PiV is An Alkyl Uradical containing 1 to 4 carbon atoms, a vinyl radical, an allyl radical, or a phenyl radical and, X( is chlorine or bromine, The Grignard reagents usefutl ljcreiri are 'those reagents commonly Ihnown in the art for Griqgnard type reactions, Such materials Are$ for example, alkyl. mavreaitlm halides and aryl magnesium halides. For puwponea of tt Invention, it is preferred to u.,se Orignard roagento havix the general formuila F~ MgX wherein Rv is an a2klradicail of 1 to 4 carbon atoms, a vinyl radical, aft Allyl radiil, or phenyl radioal and X is either chlorine or );%rorine. Moast .preferred GrXgnard reagents are Otv~gCl, CHjMg~rt

(CH

2 =Cfl)MgCl, (CH2=CH)MgBr, (O 4 Hg)Mql, and (C4fls)Mgt~r.

Typical Grignard reaction solvents can be used With alkyt ethers and tetrahydrofuran being preferred. The ortjafQlithiumi compoundrh useful herein are of the general formu~la RiVt4. wherain RiV is an alkyl radioal, of 1 to 4 catbon atoms, a vinyl radical, an ally. radicaal2 or a phenyl radioca MethyllithiUm io the preferred orqanolithium' COMPOUndL -12- Suitable solvents for the organolithium compounds include toluene, xylene, benzene and ethers. Combinations of Grignard reagents and/or orgainlithium compounds may also be used. For best results, dry reaction conditions should be observed. Solvents for the starting non-derivatized alkylpolysilanes can be any organic solvent in which the material is soluble and which does not react with the material except in the desired manner. Examples of useful solvents include toluene, xylene, benzene, tetrahydrofuran and ethers.

Specifically, toluene is preferred. Generally, it has been a found preferable to add the non-derivatizoe' alkylpolysilane S to an excess of Grignard reagent or organolithium compound, both in a solvent solution. This addition and reaction is carried out while the materials are stirred or otherwise o agitated The reaction is carried out in a dry inert atmosphere such as in the presence of nitrogen or argon gas .o prevent the introduction of water into the reaction S vessel, The reaction can be run at temperatures of 0 to 10 0 °C but preferably the reaction is run at room temperature or slightly below room temperature to prevent o: decrease undesirable side reactions. After the addition of the Sreagent is complete, the reaction mixture is stirred i :r a time, with or without heating, to ensure the completion of the reaction. Typically, the reaction is carried out for a Stime period of about I to 48 hours. Excess Grignard reagent or organolithium compound is then destroyed using water, HCI, ar. alcohol, or an aqueous NH4Cl solution, The reaction mixture is cooled to room temperature and then filtered by conventional means and the solvents and other volatile materialZ are then removed by stripping under vacuum with the addition of heat, The general procedures for such replacement reactions are described in more detail in U.S.

Patent 4,298,559. The resulting derivatized alkylpolysilanes

I

Ik I ;i_ ii -13containing additional alkyl, vinyl, allyl, or phenyl groups are solids. The resulting alkylpolysilanes are of the general formula (R 2 Si)(RSi)(R'Si) where each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms, where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A X Si(CH 2 where Y (3-Y) each A is independently selected from a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an S integer equal to 0 to 3, X is chlorine or bromine, and z is San integer greater than or equal to 1, where there are from 0 to 40 mole percent (RzSi) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and radicals selected from the group consisting of additional S" alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, allyl radicals, and phenyl radicals. Preferably, S the resulting alkylpolysilanes contain 0 to 40 mole percent o (R 2 Si) units, 40 to 99 mole percent (RSi), and 1 to 30 mole percent (R'Si) units.

"o The derivatized alkylpolysilanes containing

S(CH

3 3 SiO-radicals can be prepared using the general technlquei of U.S, Patent 4,310,481. Such derivatized alkylpolysilanes can be prepared by reacting the non- 4,4 I derivatized alkylpolysilanes of this invention with hexamethyldisiloxane. Generally, the reaction is carried out adding (CH 3 3 SiOSi(CH 3 3 and a strong acid such as F 2 CS03H or sulfuric acid to the non-derivatized alkylpolysilane in an organic solvent and then adding water with agitation. The reaction may be carried out at room temperature to 125 0 C but it is generally preferred that the reaction temperature be about room temperature or slightly above room temperature to prevent or decrease undesirable side reactions. After the The following statement is a full description of this invention, including the best method of peforming it 1.

I LL -14addition of the disiloxane, acid, and water is complete, tne reaction mixture is stirred for a time, with or without heating, to ensure the completion of the reaction. The reaction mixture is then cooled to room temperature and filtered by conventional means. The solvent and other volatile materials are removed by vacuum stripping. The general procedures for such siloxylating reactions are described in more detail in U.S. Patent 4,310,481. The resulting (CH,) 3 SiO-containing alkylpolysilanes are solid at room temperature. These (CH 3 3 SiO-containing alkylpoly- 4-14 ro silanes are of the general formula (R 2 Si)(RSi)(R'Si) where each R is independently selected from alkyl radicals Scontaining 1 to 4 carbon atoms, where R is selected from the o group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula AyX X 3y)Si(CH 2 where each A is independently selected from a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X is chlorine or Sbromine, and z is an integer greater than or equal to 1, vhere there are from 0 to 40 mole percent (R 2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and (CH,) 3 SiO- radicals. Preferably, the S g, (CH 3 ),SiO-containing alkylpolysilanes contain 0 to 40 mole o: percent (R 2 Si) units, 40 to 99 mole percent (RSi), and 1 to mole percent (R'Si) units.

The derivatized alkylpolysilanes containing hydrogen attached to silicon can be prepared using the general techniques of U.S. Patent 4,310,482. Such derivatied alkylpolysilanes can be prepared by reacti g the non-derivatized alkylpolysilanes of this invention with a reducing reagent such as lithium aluminum hydride under anhydrous conditions. Generally, the process consists of placing the reducing agent (as a slurry in a dry solvent) in a reaction vessel which is purged with an inert gas. The non-derivatized alkylpolysilane is then added to the slurried reducing agent over a period of time to control any exotherm.

After the addition, the mixture can be refluxed to ensure complete reaction or can be stirred at room temperature for several hours. Excess reducing agent can be destroyed by the addition of aqueous sodium hydroxide. The reaction may be filtered if desired. It is preferred that the reaction mixture be dried, using, for example, MgSO4, and then n filtered. The reaction mixture may then be vacuum stripped to obtain the desired solid, hydrogen-containing alkylpolysilanes. The general procedures for such reduction reactions are described in more detail in U.S. Patent 4,310,482. These hydrogen-containing alkylpolysilanes may be described by the general formula (R 2 Si)(RSi)(R Si) where each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms, where R' is selected from the group consisting of alkyl radictls of at least six carbon atoms, phenyl radicals, and radicals of the formula AyX(_y)Si(CH2) where each A is independently selected from a hydrogen atom or alkyl radicals 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, where there are from 0 to 40 mole percent (R 2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and hydrogen ators. Preferably, the hydrogen-containing alkylpolysilanes contain 0 to 40 mole percent (R 2 Si) units, to 99 mole percent (RSi), and 1 to 30 mole percent (R'Si) units.

The derivatized alkylpolysilanes containing amine and substituted amine groups attached to silicon can be r .itlY-.1)1ISS~--C.

-16prepared using the general techniques of U.S. Patent No.

4,314,956. The amine and substituted amine groups can be described by the general formula -N(RV)2 where RV is hydrogen, an alkyl radical containing 1 to 4 carbon atoms, a phenyl radical, or a -SiA' 3 radical where each A' is independently selected from hydrogen, alkyl radicals containing 1 to 4 carbon atoms and vinyl. The aminolysis reagents useful in this invention are ammonia or substituted or unsubstituted organic amines having the general formula N(RV)22 where R V is a hydrogen atom, an alkyl radical of 1 to 4 carbon atoms, a phenyl radical, or a -SiA' 3 radical where each A' is independently selected fron, hydrogen, alkyl radicals of 1 to 4 carbon atoms and vinyl. Examples of *suitable aminolysis reagents include NH,, CHNH,, (CH3)2NH, 00 00

SC

4

H

9

NH

2 (CH3)3SiNH2, and aniline. Combinations of these ,0 *0 aminolysis reagents may also be employed. By treatment with such aminolysis reagents, the chlorine or bromine atoms are replaced by radicals of formula -N(RV) 2 Generally, the Soo0 aminolysis reagent is used in a stoichiometric excess based ".o"o0 on the amount of halocten present in the non-derivatized alkylpolysilane to ensure that the aminolysis reaction is o 4 enhanced. Excess reagent as well as any solvents and by-products can be stripped or strip distilled at the end of the reaction. For best results, dry reaction conditions should be observed. Solvents for the starting non-derivatized alkylpolysilane can be any organic solvent in which the material is soluble and which does not react with the material except in the desired manner. Examples of useful solvents include toluene, xylene, benzene, tetrahydrofuran and ethers. Specifically, toluene is peeferred.

Generally, the order of addition of the components is not critical, but it has been found preferable to add the neat aminolysis reagent to the non-derivatized alkylpolysilane in

:II..

-17a solvent solution, such as toluene. This addition and reaction is carried out while the materials are stirred or otherwise agitated. The reaction is carried out in a dry inert atmosphere such as in the presence of nitrogen or argon gas to prevent the introduction of water into the reaction vessel. After the addition of the aminolysis reagent is complete, the reaction mixture is stirred for a time, with or without heating, to ensure the completion of the reaction.

Typically the reaction time is about 3 to 96 hours. The reaction can be run at temperatures of 25 0 C to 100°C but preferably the reaction is run at reflux temperature. The 49Q0 0 o reaction mixture is cooled to room temperature and then "filtered by conventional means and the solvents and other 0 volatile materials are then removed by stripping under vacuum with or without the addition of heat. The resulting o alkylpolysilanes are solids at room temperature. The general procedures for such reactions are described in more detail in U.S. Patent 4,546,163. These amino-substituted alkylpoly- #0 silanes may be described by the general formula o" 0

(R

2 Si)(RSi)(R'Si) where each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms, where R' is Sa selected from the group consisting of alkyl radicals of at PoO.-. least six carbon atoms, phenyl radicals, and radicals of the formula A X, _Si(CH 2 where each A is independently selected from a hydrogen atom or alkyl radicals 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, where there are from 0 to 40 mole percent (R 2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and radicals of the formula -N(RV)2 where Rv is hydrogen, an alkyl radical containing 1 to 4 carbon atoms, a phenyl radical, or a -SiA'3 radical where radicals of the formula A X 3_y)Si(CH2)z- where each A is I i to 40 mole percent (R 2 Si) units, 40 to 99 mole percent (RSi), and 1 to 30 mole percent (R'Si) units.

under anhydrous conditions, with a reagent selected from the radicalsoup consitaing of (i alkyl orthoformates haand vinyl. the general formula (RO) 3 CH, (ii) carbinols having the general formula R' 'OH, and (iii) alcoholates having the general Preferably, the amine-substis anuted alkyl radipolysilanes containing 1 to 4 to 40 mole percent (RiSi) units, 40 to 99 mole percent (RSi), Ij and 1 to 30 mole percent (R'Si) units. i carbon aThe derivatized alkyl radysilanes containing alkoxy 4 carbon atoms or a phenyl radical, and M is sodium, potassium, or phenoxy groups By treattached to silicon can be prepared usthe chlorine or bromine atoms are replaced by radicals of formulae RO- and the general treating reagents are of threReissue Patdifferent 47types; These alkoxy- or phenoxy-containing alkylpolysilanes may be prepared by reacting the non-derivatized alkylpolysilanes, ij o' under anhydrous conditions, with a reagent selected from the namely,group consistingalky of alkyrth orthoformates having the general formula Sgeneral formula (RO)CH,CH, (ii) carbinols having the general formula R, and Sformula ROH, and (iii) alcholates having the general formula RM and in which R I formula where R is an alkyl radical containing 1 to 4 is an alkyl group of 1-4 carbon atoms, R is an alkyl group of 1 to 4 carbon atoms or a phenyl radical, and M is sodium, potassium or lithium. By treatment ithSpecific examples of materials useful in this bromine atoms are replaced by radicals of formulae RO- and invention are CHreati reagents are of three different types; LiOCH, 2 CU, (CH 3

O)

3 CH, (CH 3

CHO)

3 CH and phenol. Preferred for this invention are the alkyl orthoformates and alcoholates.

:i *Most preferred ins havingCH the general formula R OH, eagents may Si also be employed.holates hing the general formula ROMgent is used in which R stoihiometric excess based carbon the amount of his an al kyen present n of 1 the nonderivbon atoms and phenylpoysiand M is sodium, potassiumure that the or lithium. Specific examples of materials useful in this I invention are CH,OH, CHCH2OH, CH,(CH2),OH, NaOCH,, KOCH,, LiOCH2CI,, (CH,O)3CH, (CHjCH O) CH and phenol. Preferred for this invention are the alkyl orthoformates and alcoholates.

Most preferred is NaOCH,. Combinations of these reagents may also be employed. Generally, the reagent is used in a stoichiometric excess based on the amount of halogen present in the non-derivatized alkylpolysilane to ensure that the ILueger greater than or equal to 1, with 3 i'l y l i; fl At:i k

V

I

-19o a~ o 8 4 4B 4 48 40 4 neC oa i 04 4 4o 0 0 alcoholysis reaction is enhanced. Excess reagent as well as any solvents and by-products can be stripped or strip distilled at the end of the reaction. For bes3t results, dry reaction conditions should be observed. Solvents for the starting non-derivatized alkylpolysilanes can be any organic solvent in which the material is soluble and which does not react with the material except in the desired manner.

Examples of useful solvents include toluene, xylene, benzene, tetrahydrofuran and ethers. Specifically, toluene is preferred. Generally, the order of addition the components is not critical, but it has been found preferable to add the neat reagent to the non-derivatized alkylpolysilane polysilane in a solvent solution, such as toluene.

This addition and reaction is carried out while the materials are stirred or otherwise agitated. The reaction is carried out in a dry inert atmosphere such as in the presence of nitrogen or argon gas to prevent the introduction of water and air into the reaction vessel. After the addi,tion of the reagent is complete, the reaction mixture is stirred for a time, with or without heating, to ensure the completion of the reaction. Typically the reaction time is about 1.5 to hours. The reaction can be run at temperatures of 25 0 C to 110 0 C but preferably the reaction is run at reflux temperature. The reaction mixture is cooled to room temperature and then filtered by conventional means and the solvents and other volatile materials are then removed by stripping under vacuum with or without the addition of heat.

The resulting derivatized alkylpolysilanes are solids at room temperature. The general procedures for such alkoxylating or phenoxylating reactions are described in more detail in U.S.

Reissue Patent Re. 31,447. The resulting alkoxy- or phenoxy containing ulkylpolysilanes are of the general formula

(R

2 Si)(RSi)(R'Si) where each R is independently selected ft

(I

silicon and a catalyst. See Eaborn, "Organosilicon U 'i i alikyl radicals containing 1 to 4 carbon atoms, where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A X (y)Si(CH) z- where each A is independently selected from a hydrogen atom or alkyl radicals 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, where there are from 0 to 40 mole percent (R 2 Ai) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon on atoms other silicon atoms and radicals of formula where is an alkyl radical containing 1 to 4 carbon atoms So" or a phenyl radical. Preferably, the resulting alkylpolysilanes contain 0 to 40 mole percent (RSi) units. 40 to 99 Smole percent (RSi), and 1 to 30 mole percent (R'Si) units, The resulting derivatized alkylpolysilaneB, are solids at 25 0 C and have the general formula (R 2 Si)(RSi)(R -i) where each R is independently selected from alkyl radicals o: 0, containing 1 to 4 carbon atoms, Where R' is selected from the o group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula AyX Si(CH 2 z where each A is independently selected from o a hydrogen atom or alkyl radicals containing 1 to 4 carbon atoms, y is an integer equal to 0 to 3, X is chlorine or 0 00 bromine, and z is an integer greater than or equal to 1, and where there are from 0 to 40 mole percent (R 2 Si) units, 1 to 99 mole percent (RSi), and 1 to 99 mole percent (R'Si) units, where there are also bonded to' the silicon atoms other silicon atoms and radicals selected from the group consisting of hydrogen, additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, allyl radicals, phenyl radicals, (CH,) 3 Sio-radicals, radicals, and -N(Rv) 2 radicals where is an alkyl radical of 1 to 4 carbon silicon and carbon content of the ceramic materials procucea -2] atoms or a phenyl radical and R v is hydrogen, an alkyl radical of 1 to 4 carbon atoms, a phenyl radical, or a -SiA" radical where each A is independently selected from hydrogen, alkyl radicals containin.g 1 to 4 carbon atoms and vinyl. Preferably, the derivatized alkylpolysilanes contain 0 to 40 mole percent (R 2 Si) units, 40 to 99 mole percent (RSi) units, and 1 to 30 mole percent (R'Si) units. It is most preferred that the derivatized alkylpolysilanes contain from 0 to 10 mole percent (R 2 Si) units, 80 to 99 mole percent (RSi) units, and 1 to 20 mole percent (R'Si) units.

Especially preferred derivatized alkylpolysilanes I are the derivatized methylpolysilanes of general formula

((CH

3 2 Si)(CHSi)(R'Si) where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula AX Si(CH2) where each A is independently selected from y z a hydrogen atom or alkyl radicals 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 and where there are from 0 to 40 mole percent ((CHI) 2 Si) units, 1 to 99 mole percent (CHISi) units, and 1 to 99 mole percent (R'Si) units, where there are also bonded to the silicon atoms other silicon atoms and radicals selected fro., the oup consisting of hydrogen, additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, phenyl radicals, (CH,),SiO-radicals, radicals, and NHR Sradicals where is an alkyl radical of 1 to 4 carbon j atoms or a phenyl radical and R is hydrogen, an alkyl radical of 1 to 4 carbon atoms, a phenyl radical, or an -SiA' radical where each A' is independently selected from alkyl radicals containing 1 to 4 carbon atoms. Preferably, the derivatized methylpolysllanes contain 0 to 40 mole percent (RSi) units, 40 to 99 mole percent (RSi) units, and 1I__~1I -22- 1 to 30 mole percent (R'Si) units. It is most preferred that the derivatized methylpolysilanes contain from 0 to 10 mole percent ((CH 3 )2Si) units, 80 to 99 mole percent (CH 3 Si) units, and 1 to 20 mole percent (R'Si) units.

The most preferred derivatized alkylpolysilanes are the derivatized methylpolysilanes of the general formula 2 Si)(CH3Si)(R'Si) where R' is selected from the group consisting of alkyl radicals of t least six carbon atoms, phenyl radicals, and radicals of the formula A X Si(CH 2 where each A is independently selected from a hydrogen atom or alkyl radicals 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 and where there are from 0 to 40 mole percent ((CH3) 2 Si) units, 1 to 99 mole percent (CH3Si), and 1 to 99 mole percent (R'Si) units, where there are also bonded to the silicon atoms other silicon atoms and additional methyl radicals. Preferably, these additional methyl radicals attached to silicon are introduced via a methylation reaction using methyllithium, Preferably the derivatized methylpolysilanes contain 0 to mole percent (R 2 Si) units, 40 to 99 mole percent (RSi) units, and 1 to 30 mole percent (R'Si) units, It is most preferred that this derivatized methylpolysilaiae contain from 0 to mole percent ((CH3),Si) units, 80 to 99 mole percent (CF 3 Si) units, and I to 20 mole percent (R'Si) units.

These derivatized alkylpolysilanes may contain residual chlorine or bromine atoms and still be useful in this invention. The chlorine or bromine content of these derivatized alkylpolysilanes is, however, less than the chlorine or bromine content of the iktarting non-derivatized alkylpolysilanes. Preferably, the derivatized alkylpolysilanes contain less than 5 weight -percent chlorine or bromine; more preferably, they contain less than 2 weight ;~iC-pYlrp-rr~la~-.ra~ ICIC^ I~ II I -23percent chlorine or bromine; and most preferably, they contain less than 1 weight percent chlorine or bromine, The reduced levels of chlorine or bromine in these derivatized alkylpolysilanes result in easier and safer handling of the derivatized alkylpolysilanes relative to the non-derivatized alkylpolysilanes which contain significant amounts of chlorine of bromine, The derivatized alkylpolyslanes of this invention may be converted to ceramic materials by pyrolysis to an elevated temperature of at least 750 0 C in an inert atmosphere, vacuum or ammonia-containing atmosphere for a time sufficient to convert them to a ceramic material, Preferably, the pyrolysis temperature is from about 1000 0 C to about 1600 0 C. If the preceramic polymers are of sufficient viscosity or if they possess a sufficiently low melt a: temperature, they can be shaped and then pyrolyzed to give a ceramic shaped article such as a fiber, Preferably, the preceramic polymer of this invention have a aOtening or glass transition temperature of about 50 to 3006C and most SCO preferably in the range of 70 to 200 0 C. Such a settening temperature allows for the formation of pregqramic fibers by known spinning techniques, As noted earlier, the softening or glass transition temperatures of the derivatized alkyl= polysilanes can be controlled by varying the content of the (R'Si) units in the non-derivatized alkylpolysilanes.

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. The examples are intended to illustrate the invention and are not intended to limit the invention, In the following examples, the analytical methods used were as follows: -24- The glass transition temperature, T9.was determined on a Thermomechanical Analyzer, Model 1090, from Dupont Instruments, The glass transition temperature is related to the goftening point, Carbon, hydrogen, and nitrogen were determined on a C, H, N Elemental Analyzer, Model 1106, manufactured by Carlo Erba Strumentazi~one of Italy, The sample was combusted at 1030 0 C and then passed over a chromium oxide bed at 650 0 and a copper bed at 6 500C. The C0 2 and H 2 0 produced were then separated and detected using a thermal conductivity 604 detector, Percent silicon was determined by a fusion technique which consisted of converting the silicon material to soluble forms of silicon and then analyzing the soluble material quantitatively for total silicon by atomic absorption spectrometry. Percent chlorine was determined by fusion of the sample with sodium peroxide and potentiometri.c titratiton wJth silver nitrate. Oxygen was determlined "sing a L~ego Oxygen Analyzer equipped with an Oxygen peterrninatet 316 ~'>(Model 783700) and an, Electrode Furnace EF1OG (Model 77600) manufactured by Lklco Corporation., St. Joseph* Michigan, %he oxygen method, lavolves the high temperaturle carbotbertnic reduiction to CO with CO analysis by TR, Thermogravimetric analyses wecre varried out on a Notzsch STA 429, (24000C) TGA 4-IstruM -ht Manxacttured LY N'etzsch Instrumvents, Seib, West GermAny, The preqeramic polymers war(e fired to elevated terqperat~re Usidhg an Astro Industrias Furnace lOOQA (vato, cooled graphite heated mnodel 1000.3060-FP-12), a LlndbdriS furnace (Reavy Duty SB Type S4877A)t or the TGA instrument.

Chlorine-containing metbylpolysilanes of the general formula )2Si)(C14Si~, Si) w~j!prparec by tI." general procedures outlined in)J. Irvon PApp'OAt-n, KNOc--351 It. the names ef Duane lyEj1~ Ere~rew, and Thomnas Fay ey Ern, tili"J*e Prerm- Pi -I .1e-twas fi led as h preet -ppleat-er Unless otherwise indicated, all procedures, including polymer preparation and derivati.zation, were carried~ out under an, inert atmosphere of nitrogen or argon.

Examples 1 through 6 demonstrate the preparation of derivatized polysilanes by allcylation using organolithium compounds and/or Grignard reagents, ExampRn' 1 Four different chlorine-containing polysilanes containing (CHI(C I 2 7 units were prepared using the procedure's of the above described U,$4 Patent Application Stokrial No, 945,126E entitled "Polysilane. Preceramic Polymers" by reacting 436,0 g (2 moles) of a mixture of disilanes and 24.85 q (0.1 moles) n-octyltrichlorosi lane in the presence of 4.4 g tetra-n-butylphosphonium bromide uinder an inert atmosphere. The disilane mixture was a Direct Process residue which contained about 5.0 percent j) 2 Ql~i) 2 32.9 percent (CH,)gClSiSICl 2 CHj, 57,3 percent (CH3Cl 2 Si) 2 And 0.8 percent low boiling chlorosilanes, For sample A, the reaction temperaitu.re was raised from room temperature to 1506C At a rate of 2.0 0 C/mini held at 150 0 C for 16 minutes, and from 150 to 270*C at a rate of 3.0 0 0/min; for sample B, from room temperatUre to 1.l06C at a rate of 6,0 0 C/min, from 110 to 1500C at 2,0OC/min, and 150 to 280 0 C at 5,0 0 C/min, for sample C, from roomn temperatture to 110CC at a rate of 0 0/min and from 110 to 2800C at 5.

0 0C/min; and for sample, 1) from room~ tempert'ture to 1080a~ at a rate of 2.01 0 /ndn and 108 to 25Q 0 C at 1.SQC/min. By-produced Vo1,atilo pr,,dttcts were removed by distlation duriaj the course of the reactions,, The dhlorIne-ontaJxdnrq polysilane.4 Wore

I

C

-26estimated to contain about 20 percent chlorine. Aftter cooling the chlorine-cntaining polysilanes to room temperature, various alkylating reagents were slowly added to -the polysilanes dissolved in toluene (about a 20 percent solution) in the same reaction setup used to prepare the polysilanes. Tor sample A. the alkylating agent was 9.7j g (0.44 moles) methyllithium in diethylether. For B, the alkylating agent was 45.9 g (0,35 moles) vinyl magnesium bi~omide in tetrahydrofuran. For sample C, the alkylating agont was 6.6 g (0.30 moles) methyllithium and 13.1 g (0.10 moles) vinyl. magnesium bromide in tetrahydrofuran. For sample D, the alicylating agent 4z-s 34.1 g (0.26 moles) vinyl magnesium bromide and 1.9.4 1; (0,26 moles) methyl magnesium O chloride in totriahydrofuran, UJpon addition of the alkylating agent an exothe:, m was generally. observed, The rea,-,tion a0mixtures were ther, heated to about 100 0 C for up to miinutes, Genierally-, a 2.arga amount of salt prec:Lpi,tated from solution, After cooling to room temperatare, a saturated Saqueous solutIon of NH4Ci was added mi~til the precipitated Ssalt tu.rnad into a gray mass, The reaction mixture was filtered and the resulting filtrate was stripped, to obtained :the desired derivatized methylpc'lysi lanes. The derivatized samples A, C, and D were soluble in toluene; derivatized sample B was partly soluble in toluene4. The following results were obtained on the methylated rethylpolysilanes.

-27- A B C D T C 38.0 61.0 49.8 g Si, 47.1 32.8 45.5 38.5 C, 39.4 18.7 38.4 36.1 H, 9.5 5.7 9.3 8.3 0, 5 5.2 8.1 1.3 C1, 8.1 6.7 7.1 Polymer SYield 60.5 57.2 56,4 54.8 Molecular S We ight (g/mole): Num. Av. 675 1020 1044 865 S Wt. Av. 922 2928 1771 2106 0 0 The derivatized methylpolysilane A was fired to 1 1200°C under argon at a rate of about 5.0 0 C/min, The ceramic o o yield was 31.5 percent. The ceramic contained 70,0 percent

O

v silicon, 28.7 percent carbon, non-detectable levels of oo I hydrogen and nitrogen, and 1.10 percent oxygen. Samples C and D were converted to ceramics in yields of 61.0 and 67.2 percent, respectively, by firing to 12000C under an argon S atmosphere.

Example 2 S* Several different chlorine-containing polysilanes containing (CgHSi) units were prepared using the general procedures outlined in Example 1, For sample A, 437.6 g (2 moles) disilanes were reacted with 10.8 g (0.05 moles) phenyltrichlorosilane in the presence of 4.8 g tetran-butylphosphonium bromide by heating the mixture from room temperature to 250 0 C at a rate of 1.50°C/min. For sample B, 436.0 g (2 moles) disilanes were reacted with 63,45 g (0.3 -LII~ i i C i -28moles) phenyltrichlorosilane in the presence of 4.4 g tetran-butylphosphonium bromide by heating the mixture from room temperatuire to 270 0 C at a rate of 3.6 0 C/min and holding the reaction temperature at 270 0 C for ?0 minutes. The disilanes were the same as used in Example 1. The resulting chlorinecontaining polysilanes were then reacted with methyllithium using the same procedure as in Example 1. Polysilane A, dissolved in a toluene and diethylether mixture, was reacted with 10.8 g (0.49 moles) CH3Li in dicthylether. Polysilane B, dissolved in toluene, was reacted with 6.8 g (0.31 moles) .o CH 3 Li in diethylether. The derivatized polysilanes were soluble in toluene. The following results were obtained on 0' the methylated methylpolysilanes.

o" A C STg, C 136.4 122.0 Si, 54,7 43,9 a, C, 34,3 44.3 o oo H, 7.3 o O, 0.8 0.8 S C1, 0.3 0.1 Polymer Yield 53.1 67.5 'Molecular Weight (g/mole): Num. Av. 642 744 Wt. Av. 1018 1208 The derivatized methylpolysilanes were converted to ceramic materials by pyrolysis at 1200 0 C under argon as in Example 1. The following results were nbtained.

1 -29- A C Ceramic Yield, 32.5 53.8 Si, %68.4 61.9 C, 29.8 38.1 0, 0.68 0.55 Cl, 0.08 Example 3 Several chlorine-containing polysilanes containing a% both (CH 3

(CH

2 7 Si) and (C 6 HsSi) units were prepared using the general procedures outlined in Example 1. For sample A, S disilanes (437.6 g, 2 moles) were reacted with 20.9 g (0.08 0 0 o moles) n-octyltrichlorosilane and 25.1 g (0,12 moles) phenyltrichlorosilane in the presence of 4.9 g tetra-n-butylphosphonium bromide by heating the mixture from room ,o temperature to 250 0 C at 2.0 0 C/min. For sample B, disilanes (436.0 g, 2 moles) were reacted with 24.85 g (0.1 moles) n-octyltrichlorosilane and 63,45 g (0.3 moles) phenyltrichlorosilane in the presence of 4.4 g tetra-nbutylphosphonium bromide by heating the mixture from room temperature to 110 0 C at a rate of 10.0 C/min, held at 1100C for 8 minutes, from 110 to 150 0 C at 2.0°C/min, and from 150 to 300 0 C at 5.0 0 C/min. The disilanes employed were the same S as in Example 1. The resulting chlorine-containing polysilane A in toluene and diethylether was reacted with 13.6 g (0.62 moles) of methyllithium in diethylether as in Example 1. The resulting chlorine-containing polysilane B in toluene was reacted with 10.1 g (0.46 moles) of methyllithium in diethylether as in Example 1, The derivatized polysilanwere soluble in toluene. The following results were obtainn I on the methylated methylpolysilanes.

A C Tg9 C 30.0 52.6 Si, %45.7 39.0 C %43.4 46.9 H, 8.3 7.8 0, %0.5 3.3 Cl, 0.1 0*0 P~Q olymer 0 Yi eld 72.5 75.3 SMolecular We ight 00 (g/mole): 0 0Num. Av. 548 774 Wt. Av. 844 1069 The derivatized nmethylpolysilanes were converted to ceramic materials by py~'olysis at 1200'C under argon as in Example 1. The following results were obtained.

A C 00Cerami c 0:si, %66.3 60.8 C, 31,8 37.9 0, 0.86 1,82 Clj 0.17 Example 4 Two chlorine-containing polysilanes containing ((QH)yCl (3-)Si(CH 2 2 Si) units where y is 2 or 3 were c II": -31prepared using the same procedures and disilanes as in Example 1. For sample A, 436 g (2 moles) disilanes was reacted with 128 g (0.5 moles) (CH,) 2 ClSiCH 2

CH

2 SiC1l in the presence of 4.4 g tetra-n-butylphosphonium bromide by heating the reaction mixture from room temperature to 284 0 C at a rate of 2.0°C/min. For sample B, 436 g (2 moles) disilanes was reacted with 23.6 g (0.1 moles) (CH 3 3 SiCH 2

CH

2 SiCl3 in the presence of 4.4 g tetra-n-butylphosphonium bromide by heating the reaction mixture from room temperature to 300 0 C at a rate of 3.0 0 C/min. Both derivatized polysilanes were soluble in toluene. The following results were obtained on the o' 0 methylated methylpolysilanes.

S 0o SA B 0 00.

a Tg C 58.0 97.0 Si, 41.5 54.6 SC. 34.2 32.4 o H, 0 8.5 8.3 o X% 0.5 0.4 0 01 CL, 3.2 1.9 j o Polymer Yield 46.5 54,6 Molecular Weight (g/mole): Num. Av. 806 713 Wt. Av. 1348 1122 The derivatized methylpolysilanes were converted to ceramic materials by pyrolysis at 1200 0 C under argon as in Example 1. The following results were obtained. Chlorine was not determined.

1. -32- A B Ceramic Yield, 25.7 62.3 Si, 67.4 66.2 C, 28.6 30.4 H, 0.05 0.16 0, 1.75 0.43 Example A chlorine-containing polysilane containing both (CH3(CH 2 Si) and (Cl3SiCH 2

CH

2 Si) units was prepared using the general procedures outlined in Example 1. Disilanes (436 g, 2 moles) were reacted with 24.85 g (0.1 moles) n-octyltrichlorosilane and 29.7 g (0.1 moles) SClSiCH 2

CH

2 SiC1 3 in the presence of 4.4 g tetra-n-butylphosphonium bromide by heating the mixture from room temperature to 110°C at a rate of 20.0°C/min and from 110 to 250°C at 2,0 0 C/min. The disilanes employed were the Ssame as in Example 1. The resulting chlorine-containing polysilane in toluene was reacted with a mixture of 7.7 g (0.35 moles) of methyllithium in diethyl ether and 28.2 g (0,1 moles) phenyl magnesium bromide in tetrahydrofuran as in Example 1. The derivatized polysilane yield was 58.5 g. The derivatized polysilane was soluble in toluene with a glass transition temperature of 124.G 0 C. The number average and weight average molecular weights were 1343 and 3951, respectively. This derivatized polysilane contained 39.4 percent silicon, 38.3 percent carbon, 8.8 percent hydrogen, and 0.5 percent chlorine. Oxygen was not determined.

-33- Example 6 A chlorine-containing polysilane containing

(CH

3

(CH

2 7 Si), (CHsSi), and (ClSiCHCCH 2 Si) units was prepared using the general procedures outlined in Example 1.

Disilanes (436 g, 2 moles) were reacted with 24.85 g (0.1 moles) n-octyltrichlorosilane, 21.1 g (0.1 moles) phenyltrichlorosilane, and 29.7 g (0.1 moles) Cl1SiCHzCH 2 SiCIl in the presence of 4.4 g tetra-n-butylphosphonium bromide by heating the mixture from room temperature to 100°C at a rate of 10.0 0 C/min and from 100 to 250 0 C at 2.00 C/min. The disilanes employed were the same as in Example 1. The resulting chlorine-containing polysilane in toluene was reacted with 17.4 g (0.79 moles) S of methyllithium in diethylether as in Example 1. The derivatized polysilane was obtained in 72,5 g yield. The derivatized polysilane was soluble in toluene with a glass transition temperature of 118,0 0 C. Tho number average and S weight average molecular weights were 1453 and 3016, Srespectively. This derivatized polysilane contained 37.4 "percent silicon, 40.7 percent carbon, 9,1 percent hydrogen, o« a and 1.3 percent chlorine. Oxygen was not determined, Example 7 SThis example demonstrates the preparation of a o* derivatized polysilane containing SiH bonds by reacting a chlorine-containing polysilane with lithium aluminium Shydride. A chlorine-containing polysilane was prepared by reacting 436 g (2 moles) disilanes with 24.85 g (0.1 moles) n-octyltrichlorosilane in the presence of 4.4 g tetra-nbutylphosphonium bromido by heating the reaction mixture from room temperature to 110° at a rate of 17.5°C/min, held at 110 0 C for 6 minutes, from 110 to 150 0 C at 2.0°C/min, fV m 150 to 300°C at 5.0 0 C/min, and holding at 300 0 C for 16 minutes using the same disilanes and procedures as in Example 1.

Lithium aluminum hydride (5.4 g, 0.095 moles) was slowly i -34added to the chlorine-containing polysilane in a solution of heptane (35 g) and diethylether (185 g) at OC. After the addition the reaction mixture was heated to 35 0 C in one hour.

Residual lithium aluminum hydride was destroyed by addition of aqueous KOH. The derivatized polysilane was obtained in 50.1 g yield. The derivatized polysilane was soluble in toluene and had a glass transition temperature of 63.0 0

C.

The number average and weight average molecular weights were 813 and 1642, respectively. This derivatized polysilane contained 49,7 percent silicon, 27.4 percent carbon, 6.7 percent hydrogen, 1.5 percent oxygen, and 7.4 percent chlorine. Both NMR and IR confirmed the presence of hydrogen 2o bonded directly to silicon.

Examples 8 through 11 demonstrate the preparation 0 S of derivatized polysilanes using various aminolysis reagents.

Example 8 A new chlorine-containing polysilane was prepared for each different derivatization reaction by reacting 436 g o 0 (2 moles) disilanes with 24,85 g (0.1 moles) n-octyltrichlorosilane in the presence of 4.4 g tetra-n-butylphosphonium bromide by heating the mixture from room Stempeyature to 110 C at a rate of 5.8C/min and from 110 to 300°C at a rate of 2.0°C/min. The disilanes employed were the same as in Example 1. In sample A, the chlorinecontaining polysilane (about 20 percent in toluene) was reacted with methylamine by bubbling methylamine through the reaction mixture. In sample B, the chlorine-containing polysilane (about 20 percent in toluene) was reacted with dimethylamine by bubbling dimethylamine through the reaction mixture. Samples A and B were treated with the organoamine until the organoamine began to condense in a water-cooled condenser attached to the reaction flask. The reaction tim was normally about 2 to 3 hours. Excess organoamine was removed by an argon purge. The derivatized polysilanes were obtained after filtering and stripping. For sample C, a percent solution of the chlorine-containing polysilane in toluene was loaded in a 2.4 liter autoclave which was pressurized to 90 psi with ammonia. The reaction continued for 16 hours at room temperature. Excess ammonia was removed by an argon purge, The derivatized polysilane C was filtered and stripped. It gelled during stripping. The derivatized polysilane C ignited upon exposure to air. Derivatized polysilanes A and B were soluble in toluene; C was insoluble, 0 The following results were obtained on the derivatized methylpolysilanes.

A B C T C 81.0 48.0 Si, 49.0 38.5 50.8 C, 34.1 32,1 31.0 H, 8.9 8,2 7.7 N, 3.9 2.0 3.2 0, 5.3 6.1 5,6 C1, 1.5 3.8 .oo< Polymer Yield 56.0 57.0 51.0 Molecular Weight (g/mole): Num. AV, 1134 1004 2431 Wt. Av. 2269 1422 8309 The derivatized methylpolysilanes were converted to ceramic materials by pyrolysis at 1200 0 C under argon as in -36- Example 1. The following results were obtained. H was non-detectable and chlorine was not determined.

A B C ydrogen Ceramic Yield, 80.0 Si, 67.7 65.0 C, 26.0 26.2 N, 4.8 2.2 0, 4.4 Example 9 Two chlorine-containing polysilanes were prepared using the procedure of Example 1. Sample A was prepared by reacting 436 g (2 moles) disilanes with 21.15 g (0.1 moles) phenyltrichlorosilane in the presence of 4,4 g tetra-nbutylphosphonium bromide. Sample B was prepared by reacting 436 g (2 moles) disilanes with 63,45 g (0,3 moles) phenyltrichlorosilane in the presence of 4.4 g tetra-n-butylphosphonium bromide. Both samples were heated from room temperature to 110 0 C at a rate of 8.0 0 C/min and from 110 to 300 0 C at a rate of 2.0 0 C/min. The disilanes employed were the same as in Example 1. Both samples were then reacted with dimethylamine using the same procedure as in Example 8 except that the present sample B was further reacted with ammonia. A 20 percent solution of the dimethylamine treated polysilane B in toluene was loaded into a 2.4 liter autoclave which was pressurized to 90 psi with ammonia. The reaction continued for 16 hours at room temperature. Excess ammonia was removed by an argon prge. The dimethylamine/ainmonia treated polysilane B was filtered and stripped. Both -37derivatized polysilanes A and B were soluble in toluene. The following results were obtained for the polysilanes.

A B Tg' C 168.0 141,0 Si, %49.2 37,8 C, %18.1 39.6 H, 516 7.1 N, 4^,S 3.8 0, X 5.2 Cl, Pol yme r Yield 57.0 31.0 Molecular Weight (g/mole):' Num. Pv. 990 Wt, Av. 1643 The deriVatized Methy.Lpolysilanes A and B were converted to ceramic materials In 74,2, and 67.8 percent yield, respectively, by pyrolysis at 120000 under argen as in Example 1, The ceramic material A contained 65.0 percent silicon, 28.5 percent carbon, tion-detectable levels of hydrogen, 2,0 percent nitrogen, and 0.93 percent oxygen, Chlorine was not determined, The composition of ceramic B was no~t determined, Example Two chlorine-containing polysilanes which contained (tCHI(CH 2 7 Si and (COH5Si) units were pr'epared by reacting 436 g (2 moles) disilanes with 24,8 g (0,1 moles) n-octyltrichlorosilane and. 21.1 g (0.1 moles) phonyltrtehlorosi lane in the presence of 4,4 q tetra-.n-butylphosphoniim, bromide -38using the same procedures and disilanes as Example 1.

Chlorine- containing polysilane A was reacted with methylamine as described in Example 8. Chlorine-containing polysilane B was reacted with dimethylamine as described in Example 8 except that after the dimethylamine flow was terminated, ammonia waia bubbled through the reaction mixture,, fo-r about 2 hours at room temperature. Both reaction mixtures were filtered and stripped to recover the desired derivatized pol.ysilanes, Both derivatized polysilanes were soluble in toluene. The following results were obtained for the A B STgI C 94,0 80,0 S, %53.2 40.7 C, 37.8 34,8 S H, %8.2 o ~Cu I, ,4 S0, %2.9 C, %1.7 1,7 S..Polymer Yieldt 62,0 69.0 Molecular Weight (g/mole): N4um. Av. 934 1020 Wt Av. 1020 1726 The derIvatized, methylpolysilanes Were converted to ceramic, materials by *)yjolysi at 120QOC under argon as in Examiple t. The following results were obtained. Hydrogen was noti-deteotable.

ii I ii- -39- A B Ceramic Yield, 69,0 59.0 si, 63.6 64,2 C, 30.6 30.8 N, 4.5 3.6 0, 0,63 Cl, Example 11 Chorine-containing pQlysilanes with (CH 3

(CH

2 7 Si) unite were prepared as in Example 8, $ample A was then treated with methylamine as in Example 8 except that a percent solution of the derivatized polysilane in toluene Was loaded in a 2,4 liter autoclave which was pressurized to psi with ammonia, The ammonia reaction continued for 16 hours at room temperature. Excess ammonia was removed by an argon purge Polysilane B was reacted with dimethylamine as described in Example 8 except that after the dimiethylamine flow was terminated, ammonia was bubbled throtiqh the reaction mixture for about 2 hours at room temperaturo, Both reaction S mixtures were filtered and stripped to recover the desired derivatized polysilanes, Both derivatized polysilanes were Soluble in toluene. The following results were obtained fort the polysilanes.

L. 4 ak A B Tg' C 140.0 69.0 Si, 47.0 45.9 C, 33.8 9 H, 8.5 8.4 N, 4.0 3,9 0, 2.5 5.2 C11 0.3 0.9 Polymer Yielc 38,0 28.2 Molecular Weight o 0" (g/mole), Num, AN, 20.36 986 Wt. Av,, 3550 1547 o "The derivatized Methylpolysilanes A and B were 0 converted tQ ceramic materials by pyrolysis at 1200'C under argon as it xaA.ple 1 with ceramic yields of 70 ,,ad 59.0 perceni, respectively.

Examiple aZ This example demonstrates the preparati/n of a derivatized poly silane which contains radicals.

Disilanes (1176.8 g, 5.4 mcles) anid n-octyltrichlorosilane (66.7 a. 0,.17 moles) was reacted In the presence of tetra-n-butylphnsphonium bromide (12.5 g) by heating the reaction mixture from room temperatuile to 90 0 C at 5,0 0 G/min, from 90 to 1.8 0 C at 2.0 0 C/min, hold at 108 0 C for 17 minutes, and from 108 to 2501C at 1.5 0 C/min The chlorine-containing polysilane was obtained in a 245.6 g yield. CH(OCi 3 3 (135 g, 1.3 moles was slowly added over a 31 minute period to the chlorine-containing polysilanG (75.2 g) in toiuene, After addition was coinpeted, the reaction mixture was i L.h _i

V

iu~ '1 -41refluxed at 79 to 100 0 C for about 1.5 hours. The methoxy-containing polysilane (52.8 g) was obtained by stripping the reaction mixture at 250 C and 20 torr for minutes. The product was soluble in toluene and contained 47.8 percent silicon, 25.8 percent carbon, 6.62 percent hydrogen, 2.83 percent oxygen, and 1 percent chlorine. The methoxy-containing polysilane was converted to a ceramic material in 63.27 percent yield by pyrolysis to 1200 C in argon. The ceramic material contained 66,2 percent silicon, 20.7 percent carbon, 0.05 percent hydrogen, 3.09 percent oxygen, and 1 percent chlorine, oaa aa a a a 4 a4 4 o 4, a 4 a Q C a4 4a a4 a4 Sa a ar ;i

LI

Claims (9)

1. A derivatized alkylpolysilane of the average formula (RSi)(RSi)(R'Si) where each R is independently selected from alkyl radicals containing 1 to 4 carbon atoms, where R' is selected from the group consisting of alkyl radicals of at least six carbon atoms, phenyl radicals, and radicals of the formula A X _Si(CH 2 where each A is y (3 y) z independently selected from a hydrogen atom or alkyl radicals S 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, where there are from 0 to 40 mole percent o" (R 2 Si) units, 1 to 99 mole percent (RSi) units, and 1 to 99 mole percent (R'Si) units, and where there are also bonded to the silicon atoms other silicon atoms and radicals selected from the group consisting of hydrogen atoms, additional alkyl radicals containinq 1 to 4 carbon atoms, vinyl radicals, allyl radicals, phenyl radicals, (CH 3 3 SiO-radicals, -OR radicals, and -N(RV) 2 radicals where R is an alkyl radical of 1 to 4 carbon atoms or a phenyl radical and R v is hydrogen, an alkyl radical of 1 to 4 carbon atoms, a phenyl OO radical, or an -SiA'3 radical where each A' is independently selected from hydrogen, alkyl radicals containing 1 to 4 carbon atoms and vinyl. 8 0

2. A derivatized alkylpolysilane as claimed in claim 1 wherein the derivatized alkylpolysilane contains 0 to mole percent (R 2 Si) units, 40 to 99 mole percent (RSi) units, and 1 to 30 mole percent (R'Si) units. LyUL3 NO.LkV-"2J2Q-LI I -43-

3. A derivatized alkylpolysilane as claimed in claim 2 wherein R' is a radical of the formula A X (3 Si(CH2) where each A is independently selected from y z a hydrogen atom or alkyl radicals 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.

4. A derivatized alkylpolysilane as claimed in claim 2 wherein there is also bonded to the silicon atoms other silicon atoms and radicals selected from the group 00 consisting of additional alkyl radicals containing 1 to 4 carbon atoms, vinyl radicals, and phenyl radicals.

A derivatized alkylpolysilane as claimed in claim 2 wherein there is also bonded to the silicon atoms so other silicon atoms and (CH 3 3 SiO-radicals.

6. A derivatized alkylpolysilane as claimed in claim 2 wherein there is also bonded to the silicon atoms other silicon atoms and -OR radicals where R- is an 1 alkyl radical of 1 to 4 carbon atoms or a phenyl radical.

7. A derivatized alkylpolysilane as claimed in claim 2 wherein there is also bonded to the silicon atoms other silicon atoms and -N(RV) radicals where R v is hydrogen, an alkyl radical of 1 to 4 carbon atoms, a phenyl radical, or a -SiA'3 radical where each A' is independently selected from hydrogen, alkyl radicals containing 1 to 4 carbon atoms and vinyl. -44-

8. A derivatized alkylpolysilane as claimed in claim 2 where the derivatized alkylpolysilane contains 0 to mole percent (RSi) units, 80 to 99 mole percent (PSi) units, and I to 20 mole percent units.

9. A method of preparing a ceramic material, said method comprising heating the derivatized alkylpolysilane of Claim 1 in an inert atmosphere or in a vacuum to a temperature of at least 750 0 C until said derivatized alkylpolysilane is converted to a ceramic material. 4 44 4 4 44 4- 44 0 00 4 0 00 DATED this 1 4t h day of D ecember 1987 DOW CORNING CORPORATION 4 o ;~o 4 4 44 Q 04 4 4,4 4 4 4 04 444 4 4 EDWD. WATERS SONS PATENT ATTORNEYS 50 QUEEN STREET MELBOURNE VIICTORIA AUSTRALIA I