A kind of synthetic method of aluminum-containing polycarbosilane

Abstract

A method for synthesizing aluminum-containing polycarbosilane, comprising the following steps: (1) placing polycarbosilane in a reactor, vacuumizing, replacing the gas in the reaction system with an inert gas to normal pressure, adding an organic solvent to dissolve, and obtaining Component a; (2) Under the protection of an inert gas atmosphere, add an oxygen-free monofunctional aluminum-containing compound to the component a obtained in step (1) at room temperature, stir, and program the temperature to 130-145 °C, and react 6-14 h, to obtain component b; (3) program the temperature of component b obtained in step (2) to 380-450°C, keep it warm for 1-5 hours, then distill under reduced pressure, and cool to room temperature to obtain aluminum-containing polycarbosilane. The aluminum-containing polycarbosilane prepared according to the method of the present invention has a low oxygen content; the use of a monofunctional aluminum source compound is beneficial to control the aluminum content; the residual Si-H content is relatively high, and there is no ultra-high molecular weight part, which is beneficial to fiber preparation; process Simple and suitable for large-scale production.

Description

technical field [0001] The invention relates to a synthesis method of aluminum-containing polycarbosilane, in particular to a synthesis method of aluminum-containing polycarbosilane with low oxygen content. Background technique [0002] The development of high-tech fields such as aerospace, weapons, and energy has put forward an urgent demand for composite materials of thermal structural materials. High-performance ceramic fibers are key raw materials for thermal structural material composites. Among them, silicon carbide (SiC) fibers have received great attention due to their excellent high temperature resistance, high strength, high modulus, and oxidation resistance. [0003] Organic precursor conversion method is the main method to prepare SiC fibers. The organic precursor conversion method is a method in which an organic polymer is used as a precursor, and after being molded using its soluble and fusible properties, it is then transformed from an organic material into ...

AI Technical Summary

Problems solved by technology

The above organoaluminum complex, aluminum acetylacetonate Al(AcAc) 3 , aluminum alkoxide, aluminum carbonyl, etc. all contain a large amount of oxygen, and oxygen will be introduced into the precursor, and polysilane or polysilane copolymer with Si-Si as the main chain will continue to break bonds and rearrange even at a high temperature of 420 °C , therefore, the reaction product at 300-420 °C may still contain Si-Si bonds, which is detrimental to the final fiber properties

[0009] In summary, in the prior art, the Al source compound in aluminum-containing polycarbosilane contains oxygen, and the commonly used raw materials such as aluminum acetylacetonate are easy to sublimate, and the reaction cannot be measured according to the setting Carried out, the obtained aluminum-containing polycarbosilane contains ultra-high molecular weight parts that are not conducive to melt spinning, and the residual Si-H bond content is low, which is not conducive to subsequent non-melting

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