Spinnable polycarbosilane and preparation method thereof

Abstract

The invention relates to spinnable polycarbosilane and a preparation method thereof. The method comprises the following steps: under nitrogen protection, adding an organic solvent and alkali metal into mixing equipment for mixing, heating the mixture until the alkali metal is molten, then adding dimethyldichlorosilane into the molten alkali metal for a reaction, and carrying out stirring and curing at a high temperature to obtain a reactant; separately adding purified water and absolute ethyl alcohol into the obtained mixture, and cleaning the mixture multiple times so as to obtain pure polydimethylsilane; conducting reacting for 1-6 hours at a temperature of 100-150 DEG C, and carrying out condensation polymerization to obtain polydimethylsilane to be treated; and carrying out pressure maintaining, vacuumizing, heat preservation, heating and cracking on the vacuum-dried polydimethylsilane to obtain a liquid low-molecular cracking product. According to the invention, excellent flowability is obtained, the branching degree of polycarbosilane is reduced, the product has a better linear structure, flowability is high, and spinnability is also obviously improved.

Description

technical field [0001] The invention relates to the technical field of polycarbosilane, in particular to a spinnable polycarbosilane and a preparation method thereof. Background technique [0002] Polycarbosilane (PCS) is a common and widely used silicon carbide ceramic precursor. PCS is prepared from polydimethylsilane (PDMS) through high-temperature rearrangement above 470°C. High-pressure, high-temperature rearrangement requires high equipment, while normal-pressure, high-temperature rearrangement has low synthesis yield and long production cycle, which lead to high production costs. At the same time, the C / Si ratio in the molecular structure of PCS is 2, and the C / Si ratio in the pyrolysis product is about 1.4, which is rich in carbon, which affects its high temperature oxidation resistance. Hyperbranched polycarbosilane (HBPCS) has attracted extensive attention from researchers due to its low viscosity, high ceramic yield, and designability of molecular structure and ...

AI Technical Summary

Problems solved by technology

High-pressure and high-temperature rearrangement requires high equipment, while atmospheric pressure and high-temperature rearrangement has low synthesis yield and long production cycle, which lead to high production costs.

At the same time, the C / Si ratio in the molecular structure of PCS is 2, and the C / Si ratio in the pyrolysis product is about 1.4, which is rich in carbon, which affects its high temperature oxidation resistance.

Hyperbranched polycarbosilane (HBPCS) has attracted extensive attention from researchers due to its low viscosity, high ceramic yield, and designability of molecular structure and performance. However, the high cost limits the development of this material. business application

[0003] The existing method for preparing spinnable polycarbosilane exists, the storage stability is not enough or the advantage of comprehensive price ratio is not outstanding, and there is no problem of commercial production and application, so it is urgent to improve

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