Radiative reduction and curing method of liquid polycarbosilane

Abstract

The invention provides a radiative reduction and curing method for liquid polycarbosilane, and belongs to the field of macromolecules and the field of inorganic non-metallic ceramics. An electron beamradiation technology is applied to reduction and curing of liquid polycarbosilane, liquid polycarbosilane containing chloromethyl groups is subjected to a radiation chemical reaction under radiationof electron beams, and cross-linking curing of liquid polycarbosilane is realized while chlorine atoms are reduced by hydrogen. The method can be directly applied to a liquid polycarbosilane dipping pyrolysis method for preparing a silicon carbide ceramic material, unsaturated bonds are not required to be introduced into liquid polycarbensilane molecular chains, or a cross-linking agent, a catalyst and an initiating agent are added to a liquid polycarbensilane precursor, curing of liquid polycarbensilane can be realized, so that not only is change of a silicon-carbon ratio of the polymer precursor in a curing process avoided, but also introduction of heteroatoms such as platinum, oxygen and nitrogen are avoided, and the method has the advantages of being simple to operate, easy to controland capable of realizing large-scale production and the like.

Description

technical field [0001] The invention belongs to the field of macromolecules and the technical field of inorganic non-metallic ceramics, and relates to a method for radiation reduction and solidification of liquid polycarbosilane. Background technique [0002] Silicon carbide (SiC) is an advanced ceramic material that has received widespread attention. It has the characteristics of high strength, low density, high temperature resistance, oxidation resistance, and good compatibility with metals. and other fields have broad application prospects. Among the SiC ceramic preparation methods that have been developed, the polymer impregnation pyrolysis method (PIP) is the most suitable method for the preparation of SiC films, SiC continuous fibers, SiC-based composites and bonded / sintered larger SiC due to the characteristics of polymers that are easy to shape and process. The most efficient method for monolithic artifacts. This method puts forward the following requirements for t...

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Problems solved by technology

However, these methods also deviate the silicon-carbon ratio of the cured polymer from 1:1, and introduce a certain amount of free carbon and SiO in the final ceramic product. 2 Such impurities seriously affect the performance of the product

[0005] (2) The hydrogenation reduction reaction of liquid polycarbosilane was not complete during the preparation process, and part of the methyl chloride could not be completely reduced

It can be seen that although the hydrogenation reduction of methyl chloride is not complete, it will not affect the composition of the final product, but it will also reduce the ceramicization rate of the liquid polycarbosilane prepared by the Grignard coupling method.

In the reported studies on the pyrolytic ceramicization of liquid polycarbosilane, no further reduction treatment of methyl chloride has been found, and an effective way to completely remove the methyl chloride contained in liquid polycarbosilane has not yet been found.

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