Method for preparing spinnable polysiloxane ceramic precursor for SiC fibers

A technology of ceramic precursors and polysiloxane, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, can solve the problem of high cost, and achieve the effect of high ceramic yield, low cost and high production yield

Active Publication Date: 2011-04-27
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a new low-cost spinnable polysiloxane ceramic precursor preparation method for the current high cost of polycarbosilane ceramic precursors for SiC fibers

Method used

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  • Method for preparing spinnable polysiloxane ceramic precursor for SiC fibers
  • Method for preparing spinnable polysiloxane ceramic precursor for SiC fibers
  • Method for preparing spinnable polysiloxane ceramic precursor for SiC fibers

Examples

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Effect test

Embodiment 1

[0020] (1) Add 16g of xylene, 12g of methyltrichlorosilane, 8g of dimethyldichlorosilane, and 2g of tetramethyldichlorodisiloxane into a three-necked flask; 2 Atmosphere protection, slowly (heating speed: 2°C / min) heat up to 82°C, then keep constant temperature, while mechanically stirring, stirring speed is 120r / min, then dropwise add potassium hydroxide aqueous solution (the mass ratio of potassium hydroxide to water is 3:10 ), the dropping rate was controlled at 3g / min, and the total amount of dropping was 104g; after the dropping was completed, it was kept at a constant temperature of 82°C for 12h; The siloxane xylene solution was taken out; (4) The xylene solvent was removed by vacuum distillation at 70°C for 1 h to obtain 15.6 g of hard white solid polysiloxane precursor (sample marked A1).

Embodiment 2

[0022] (1) 16g xylene, 12g methyltrichlorosilane, 8g dimethyldichlorosilane, 2g tetramethyldichlorodisiloxane are added to a three-necked flask; (2) vacuumize and feed N 2 Protect the atmosphere, slowly raise the temperature (heating rate is 2°C / min) to 70°C, then keep the temperature constant, and at the same time carry out mechanical stirring, the stirring speed is 60r / min, and then dropwise add potassium hydroxide aqueous solution (the mass ratio of potassium hydroxide to water is 3: 10), the dropping rate is controlled at 3g / min, and the total amount of dropping is 102g; after the dropping is completed, keep at a constant temperature of 65°C for 6h; The polysiloxane xylene solution was taken out; (4) The polysiloxane xylene solution in the upper layer was distilled at 70°C for 1 h to remove the xylene solvent, and 10.8 g of white rubbery polysiloxane precursor (sample labeled A2).

Embodiment 3

[0024] (1) Add 16g of xylene, 12g of methyltrichlorosilane, 8g of dimethyldichlorosilane, and 2g of tetramethyldichlorodisiloxane into a three-necked flask; 2 Protect the atmosphere, slowly raise the temperature (heating rate is 1°C / min) to 90°C, then keep the temperature constant, and at the same time carry out mechanical stirring, the stirring speed is 240r / min, and then dropwise add potassium hydroxide aqueous solution (the mass ratio of potassium hydroxide to water is 3: 10), the dropping rate is controlled at 3g / min, and the total amount of dropping is 104g; after the dropping is completed, keep at a constant temperature of 90°C for 18h; The siloxane xylene solution was taken out; (4) The polysiloxane xylene solution in the upper layer was distilled at 70°C for 1 hour to remove the xylene solvent, and 14.3 g of hard white solid polysiloxane precursor (sample marked for A3).

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Abstract

The invention discloses a method for preparing a spinnable polysiloxane ceramic precursor for SiC fibers, which comprises the following steps of: (1) adding chlorosilane, chlorinated siloxane and dimethylbenzene into a neck flask according to a certain mass ratio; (2) vacuumizing the neck flask, introducing N2 for protection, slowly raising the temperature to 70-90DEG C, keeping constant temperature, simultaneously performing mechanical stirring, dripping aqueous solution of an alkaline substance, and continuously stirring for reaction for 6 to 24 hours at constant temperature under the protection of the N2; (3) standing reaction liquid to separate out water and impurities of the lower layer, and taking polysiloxane dimethylbenzene solution of the upper layer out; and (4) distilling the polysiloxane dimethylbenzene solution of the upper layer under reduced pressure to remove a dimethylbenzene solvent. The compound raw materials are mature industrial materials, and are wide in sources; the reaction process is easy to control, the preparation yield is high, and the product purity is high; and the prepared polysiloxane ceramic precursor is low in cost, higher in ceramic yield and good spinnability.

Description

technical field [0001] The invention relates to a preparation method of a polysiloxane ceramic precursor, in particular to a preparation method of a polysiloxane ceramic precursor for SiC fibers. Background technique [0002] Silicon carbide (SiC) fiber is a high-strength, high-modulus, high-temperature oxidation-resistant ceramic fiber. It is one of the high-performance reinforcing fibers commonly used in advanced lightweight high-temperature resistant structural composite materials; due to its unique electromagnetic properties, it can As a radar stealth material. SiC fiber integrates structure-stealth-heat protection and is widely used in aviation, weapons, ships and some high-tech fields such as high-temperature structural materials such as engine combustion chambers and nozzles, cruise missile tail radar stealth-structural materials, etc. prospect. However, although high-temperature-resistant SiC fibers have good application prospects in aerospace, military and civil f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/06D01F9/10C04B35/565
Inventor 简科王军谢征芳王浩王亦菲薛金根陈兴波
Owner NAT UNIV OF DEFENSE TECH
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