Copolysilane and preparation method thereof

Abstract

The invention discloses copolysilane and a preparation method thereof, which relate to the preparation method of copolysilane. The preparation method comprises: in the presence of an inert gas, cooling ether solution of a metal dichlorodialkyl compound to -78 DEG C, adding a metal alkyl or metal phenyl compound, heating to room temperature and forming solution of an active catalyst; in the presence of an inert gas, introducing mixed gas of CH3SiH3 and (CH3)2SiH2 into an ether solvent cooled to -78 DEG C, making all gases liquefied and dissolved in the ether solvent, adding the solution of the active catalyst into the cooled mixed solution, heating the mixed solution, reacting till the reaction solution becomes viscous, heating again and reacting; removing the solvent from the solution of the polymer under reduced pressure after the reaction is finished, and adding a hydrocarbon solvent to dissolve the polymer, filtering to remove insoluble materials such as salts; and removing the solvent from alkyl solution under reduced pressure, heating to 80 to 180 DEG C, distilling under reduced pressure to remove a small molecular weight product, and obtaining the copolysilane. The process is simple, the cost is low, and the copolysilane is solid at normal temperature and under normal temperature.

Description

Technical field [0001] The invention relates to a method for preparing copolysilane. The copolysilane prepared by the method can be applied to the preparation of silicon carbide fibers or silicon carbide high temperature resistant ceramic-based aerospace composite materials. Background technique [0002] Past studies have shown that Cp 2 Zr(CH 3 ) 2 Can be used as a catalyst to convert CH 3 SiH 3 Catalytic dehydrogenation to prepare methyl silane homopolymer ([MeSiH] n ), and it can be properly treated and then spun, stabilized, and finally high-temperature inorganicized to obtain silicon-rich silicon carbide (SiC) fibers with C / Si of 0.9~1.0 (J.Am.Ceram.Soc. 1991, 74(3): 670-673; Ceram. Eng. Sci. Proc., 1994, 15(4): 152-161). In contrast, the current industrially produced silicon carbide fiber, its C / Si>1.2 / 1 (Chem. Rev. 1995, 95: 1443-1477), this is because the raw material used is polydimethylsilane ([Me 2 Si] n ), its C / Si=2 / 1, so the produced silicon carbide fiber is rich...

AI Technical Summary

Problems solved by technology

Silicon carbide ceramic materials with a stoichiometric ratio range of 1.0 / 1<C / Si<1.1 / 1 have excellent oxidation resistance and high temperature creep resistance, but the above-mentioned polymethylsilane or polydimethylsilane precursors are fired cannot meet the requirement of stoichiometric ratio

In addition, polymethylsilane is liquid at normal temperature and pressure, and is extremely flammable. If it is to be used as a precursor of silicon carbide ceramic materials, complex post-treatment processes such as adding chemical crosslinking agents to increase molecular weight are required, which greatly increases the cost. , and is rich in silicon, so its application as a precursor of silicon carbide ceramic fibers is greatly limited

And the currently used solid polydimethylsilane ([Me 2 Si] n ), there is a disadvantage of excess carbon content

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