Low-molecular carbon-free polysilazane and liquid-phase synthesis method thereof

A carbon polysilazane, liquid phase synthesis technology, applied in silicon compounds, chemical instruments and methods, nitrogen and non-metallic compounds, etc., can solve problems such as adverse effects on electrical properties of materials, and achieve low price and good controllability. , the effect of high purity

Inactive Publication Date: 2011-09-07
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, as the precursor of silicon nitride ceramics, the structure of polysilazane often contains a c...

Method used

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  • Low-molecular carbon-free polysilazane and liquid-phase synthesis method thereof
  • Low-molecular carbon-free polysilazane and liquid-phase synthesis method thereof
  • Low-molecular carbon-free polysilazane and liquid-phase synthesis method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Check the airtightness of the synthesis device, fully dry the whole device, evacuate, fill the container 5 with nitrogen through the inert gas branch pipe 6, and repeat the process three times to replace the air in the container 5;

[0030] (2) Add tetrahydrofuran and trichlorosilane to container 5 through silicon source raw material inlet pipe 1, wherein tetrahydrofuran is excessive; start agitator 2 to stir, so that trichlorosilane is completely dissolved in tetrahydrofuran;

[0031] (3) Start the condenser 4, pass excess ammonia gas into the container 5 through the nitrogen source raw material inlet pipe 3, heat the container 5 to 60°C through the temperature-controlled water bath 7, and let it stand for 3 hours. After the reaction is completed, protect it in an inert atmosphere Filtration to obtain a clear solution;

[0032] (4) Distill under reduced pressure at room temperature to remove the solvent tetrahydrofuran to obtain a transparent liquid, which is the c...

Embodiment 2

[0035] (1) Same as step (1) of Example 1;

[0036] (2) Add pyridine and dihydrodichlorosilane to container 5, where pyridine is excessive; start stirrer 2 for stirring;

[0037] (3) Start the condenser 4, pass excess ammonia gas into the container, let it stand at room temperature for 6 hours, and the reaction ends; filter under the protection of an inert atmosphere to obtain a clear solution;

[0038] (4) Distill under reduced pressure at normal temperature or under heating conditions to remove the solvent pyridine to obtain a transparent liquid, namely the carbon-free polysilazane of the present invention. The yield is about 70%.

[0039] The dielectric constant of the pyrolysis product of the carbon-free polysilazane synthesized in this example (ie silicon nitride ceramic) is 3.3.

Embodiment 3

[0041] (1) Same as step (1) of Example 1;

[0042] (2) Add triethylene glycol dimethyl ether and monochlorosilane to the container 5, wherein the solvent triethylene glycol dimethyl ether is excessive; start the agitator 2 for stirring;

[0043] (3) Start the condenser 4, pass excess hydrazine into the container 5, heat to 100°C, let it stand for 1 hour, and the reaction ends; filter under the protection of an inert atmosphere to obtain a clear solution;

[0044] (4) Distill under reduced pressure at normal temperature or under heating conditions to remove the solvent pyridine to obtain a transparent liquid, namely the carbon-free polysilazane of the present invention. The yield is about 75%.

[0045] The dielectric constant of the pyrolysis product of the carbon-free polysilazane synthesized in this example (ie silicon nitride ceramic) is 3.6.

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Abstract

The invention discloses a low-molecular carbon-free polysilazane and a liquid-phase synthesis method thereof, and is characterized in that the low-molecular carbon-free polysilazane is liquid state, structurally contains Si-N, Si-H and N-H bonds and does not contains carbon or other foreign elements. The liquid-phase synthesis method comprises the following steps: (1) feeding organic solvents and halogenated silicane in a container which is provided with a raw material feed pipe, a gas pipe, a stirrer and a condenser; (2) introducing an excessive amount of hydronitrogen compounds into the container, standing for 0.5 to 7 hours, filtering in an inert atmosphere to obtain a clear solution; and (3) distilling under reduced pressure at room temperature or under heating to remove the organic solvents, to obtain a transparent solution. The silicon nitride ceramics produced by cracking the low-molecular carbon-free polysilazane are excellent in dielectric properties. The starting compounds for synthesis are easily available and low in price. The synthesis device has a simple structure, is convenient to operate and has good controllability. The synthetic product has a high purity and a high yield.

Description

technical field [0001] The invention relates to a polysilazane and its synthesis method and device, in particular to a low-molecular carbon-free polysilazane and its liquid phase synthesis method and device. Background technique [0002] Silicon nitride (Si 3 N 4 ) is a covalent bond compound, which belongs to the hexagonal crystal system and has two structures: α-crystal form and β-crystal form. The chemical composition and density of the two crystal forms are the same, both are hexagonal. The difference is that the c-axis length of the α-form unit cell is about twice that of the β-form. Silicon nitride is an important non-oxide advanced ceramic material with good comprehensive properties, such as high strength, high hardness, high temperature resistance, thermal shock resistance, self-lubrication, etc. Therefore, silicon nitride is used in high temperature structural materials, High-performance bearing materials and other fields have extremely broad application prospec...

Claims

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Application Information

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IPC IPC(8): C01B21/082C01B33/00
Inventor 张长瑞李斌曹峰王思青齐共金李俊生刘荣军
Owner NAT UNIV OF DEFENSE TECH
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