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Preparation method of polydimethylsilane with uniform molecular weight distribution

A polydimethylsilane and molecular weight distribution technology, applied in the field of high-temperature ceramic materials, can solve the problems of wide molecular weight distribution of the product polycarbosilane, unsuitable silicon carbide fiber precursor, and small proportion of polymer parts, etc. The effect of large molecular weight and uniform performance

Inactive Publication Date: 2018-06-29
南昌嘉捷天剑新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the product polycarbosilane has a wide molecular weight distribution and a small proportion of polymers, so it is not suitable for use as a precursor of silicon carbide fibers

Method used

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Examples

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preparation example Construction

[0021] The invention provides a method for preparing polydimethylsilane with uniform molecular weight distribution, comprising the steps of:

[0022] S1: Dissolving refined dimethyldichlorosilane in toluene, the volume ratio of dimethyldichlorosilane to toluene is (1-2):1, to obtain the first mixed solution;

[0023] S2: Under the condition of avoiding light, put the sodium sand in the first mixed solution, add the quality of sodium sand to every 100ml of the first mixed solution is 10-15g, and under the ammonia gas environment with the flow rate of 100-200ml / min, 105 Heat to reflux at ~110°C for 24 to 36 hours, then cool to room temperature to obtain the second mixed solution;

[0024] S3: Add absolute ethanol dropwise to the second mixed solution, the volume ratio of absolute ethanol to the second mixed solution is (1-2):10, and obtain the precipitate by suction filtration;

[0025] S4: Mix the precipitate and sodium sand at a mass ratio of (1~2):1, and then place them in t...

Embodiment 1

[0030] This embodiment provides a method for preparing polydimethylsilane with uniform molecular weight distribution, comprising steps:

[0031] S1: The refined dimethyl dichlorosilane ((CH 3 ) 2 SiCl 2 ) is dissolved in toluene, and the volume ratio of dimethyldichlorosilane to toluene is 1:1 to obtain the first mixed solution;

[0032] S2: Under the condition of avoiding light, put 20g of sodium sand in 200ml of the first mixed solution, pass through ammonia gas, the flow rate is 200ml / min, keep the temperature at 105°C, heat and reflux for 24h, and then cool to room temperature to obtain the second mixed solution solution;

[0033] S3: Add 30ml of absolute ethanol dropwise to the second mixed solution, and obtain the precipitate by suction filtration;

[0034] S4: Mix 10g of precipitate with 10g of sodium sand, then place it in 100ml of toluene, pressurize to 0.2MPa under an ammonia gas environment with a flow rate of 200ml / min, keep the temperature at 160°C, and heat t...

Embodiment 2

[0039] This embodiment provides a method for preparing polydimethylsilane with uniform molecular weight distribution, comprising steps:

[0040] S1: The refined dimethyl dichlorosilane ((CH 3 ) 2 SiCl 2 ) is dissolved in toluene, and the volume ratio of dimethyldichlorosilane to toluene is 2:1 to obtain the first mixed solution;

[0041] S2: Under the condition of avoiding light, put 30g of sodium sand in 200ml of the first mixed solution, pass through ammonia gas, the flow rate is 100ml / min, keep the temperature at 110°C, heat and reflux for 30h, and then cool to room temperature to obtain the second mixed solution solution;

[0042] S3: Add 40ml of absolute ethanol dropwise to the second mixed solution, and obtain the precipitate by suction filtration;

[0043] S4: Mix 20g of precipitate with 10g of sodium sand, then place it in 100ml of toluene, pressurize to 0.5MPa under an ammonia gas environment with a flow rate of 100ml / min, keep the temperature at 180°C, and heat to ...

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Abstract

The invention relates to a preparation method of polydimethylsilane with uniform molecular weight distribution. The method comprises the following steps: dissolving dimethyl dichlorosilane into methylbenzene to obtain a first mixed solution; putting sodium sand into the first mixed solution under the dark condition, carrying out heating reflux for the first time in an ammonia environment, and cooling to room temperature to obtain a second mixed solution; dropwise adding anhydrous ethanol into the second mixed solution, and carrying out suction filtration to obtain precipitate; mixing the precipitate with sodium sand, putting the mixture into methylbenzene, and carrying out heating reflux for the second time in the ammonia environment so as to obtain a third mixed solution; dropwise addinganhydrous ethanol into the third mixed solution, and carrying out suction filtration to obtain precipitate; then, washing and drying the precipitate to obtain the white powder product polydimethylsilane. The preparation method provided by the invention is simple and does not need complicated equipment; the prepared polydimethylsilane is high in yield, large in molecular weight and narrow in molecular distribution range; after the polydimethylsilane is subjected to cracking and rearrangement, polycarbosilane which is high in high molecular weight ratio and uniform in performance can be generated.

Description

technical field [0001] The invention relates to the technical field of high-temperature ceramic materials, in particular to a preparation method of polydimethylsilane with uniform molecular weight distribution. Background technique [0002] Polydimethylsilane (PDMS) is a white powdery crystal at room temperature, insoluble and infusible. Decomposition and rearrangement reactions are prone to occur at high temperatures of 360-420°C, and the reaction product polycarbosilane (PCS) is obtained. Polycarbosilane is an important precursor material for the preparation of silicon carbide (SiC) fibers. The composition and structure of polycarbosilane play a decisive role in the performance of the prepared SiC fiber. In particular, increasing the polymer portion of PCS is beneficial to improving the strength of SiC fibers, and the molecular weight distribution of PCS also determines the spinnability of SiC fibers. In addition, the content of carbon and oxygen elements in PCS also af...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/04C08G77/06D01F9/10
CPCC08G77/04C08G77/06D01F9/10
Inventor 吴宝林侯振华
Owner 南昌嘉捷天剑新材料有限公司
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