Preparation method of polyborocarbosilane

Abstract

The invention provides a preparation method of polyborocarbosilane. The method comprises the steps of firstly, synthesizing a first raw material of silane containing -C=C; adding a certain amount of catalyst into the first raw material and a second raw material, and performing olefin metathesis reaction to obtain a first intermediate product, wherein the second raw material contains (X)nSi(Y)m, wherein X is CH2=CH-CH2- or CH2=CH-, and Y is at least one of Cl, Br, I and alkoxy; adding a reducing agent into the first intermediate product, reducing Y into hydrogen atoms by the reducing agent, andremoving solids in the first intermediate product to obtain a second intermediate product; and finally, reacting the second intermediate product with a boron-containing compound to obtain the polyborocarbosilane. The polyborocarbosilane prepared by adopting the method disclosed by the invention is high in boron content, and the boron content can be regulated and controlled.

Description

technical field [0001] The invention relates to a method for preparing silane, in particular to a method for preparing polyborocarbosilane. Background technique [0002] Boron-containing silicon carbide fiber has shown great application potential because of its outstanding high temperature resistance (Li Wenhua, Wang Jun, Wang Hao, etc. Research progress of boron-containing continuous SiC fiber by precursor conversion method, Aerospace Materials Technology, 2007, 4:5 -7.). [0003] Sylramic fiber is a typical boron-containing fiber, and its preparation process is varied. First, boron is introduced through a boron-containing atmosphere without melting during the preparation process. The disadvantages are obvious: the boron-containing atmosphere requires high corrosion resistance of equipment, and the treatment of toxic waste It is also a problem. The second preparation process uses a boron-containing precursor, which has obvious disadvantages: the polyborosilazane precursor...

AI Technical Summary

Problems solved by technology

[0003] Sylramic fiber is a typical boron-containing fiber, and its preparation process is varied. First, boron is introduced through a boron-containing atmosphere without melting during the preparation process. The disadvantages are obvious: the boron-containing atmosphere requires high corrosion resistance of equipment, and the treatment of toxic waste is also a problem

The second preparation process uses a boron-containing precursor, which has obvious disadvantages: the polyborosilazane precursor itself is extremely easy to hydrolyze and oxidize, and the synthesis of the precursor and the entire fiber preparation process must be completed in an anhydrous and oxygen-free environment. Its platform construction and production costs are extremely high

The disadvantages are obvious: boron is introduced through the dehydrogenation reaction of silicon-hydrogen bonds and boron-hydrogen, silicon-hydrogen bonds are consumed to obtain silicon-boron bonds, and the boron-containing polycarbosilane has a low silicon-hydrogen content. In the final analysis, it is due to the silicon-hydrogen content of polycarbosilane Low (0.58mol / 100g), this method is limited by the silicon hydrogen content, the boron element introduced is limited, and high boron content polyborosilane cannot be obtained