Metal modified polymethyl silicane, preparation method and application thereof

A technology of polymethylsilane and metal modification, which is applied in the field of preparation of precursor-metal-modified polymethylsilane, can solve the problems of long preparation time, low ceramic yield, high temperature oxidation resistance and other performance degradation, and achieves The effect of reducing manufacturing costs, reducing use costs, and reducing the number of cycles

Inactive Publication Date: 2008-05-28
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polycarbosilane has the following disadvantages as an impregnating agent: (1) polycarbosilane is a type of organosilicon polymer with a main chain containing a Si-C-Si structure, and the C / Si ratio in the molecule is about 1.8, which leads to The SiC ceramics prepared by it are rich in carbon, and because too many small molecules escape during the sintering process, the ceramic yield is low
The excess carbon in the ceramic product reduces the high-temperature oxidation resistance of the material; (2) the melting point of polycarbosilane is around 200°C, and a solvent needs to be added in the precursor impregnation cracking process to impregnate
This affects the impregnation efficiency and increases the cycle number of the precursor impregnation and cracking process; (3) the preparation of polycarbosilane needs to go through processes such as dimethyl monomer sodium condensation, PDMS refining, and high-temperature pyrolysis, and the total preparation time is long. higher cost

Method used

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  • Metal modified polymethyl silicane, preparation method and application thereof
  • Metal modified polymethyl silicane, preparation method and application thereof
  • Metal modified polymethyl silicane, preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] In a 1000ml three-necked flask equipped with a stirrer, a condenser, and a nitrogen inlet pipe, add 100g of polymethylsilane and 0.5g of trifluoromethylmethylsiloxane, stir well under the protection of nitrogen, and then add the crushed and refined SbCl 3 5g, control the flow of nitrogen gas at 100-1000ml / min, stir rapidly for 1-2 hours, then reduce the rotation speed to about 300-400 rpm, and react at room temperature for 10-12 hours. The HCl produced by the reaction is introduced into the water through the air duct until The gas generated by the airway will no longer turn the pH test paper red, and the reaction can be stopped; the small molecular substances are removed by vacuum filtration, and the obtained liquid substance is antimony-modified polymethylsilane, which is liquid at room temperature and has a molecular weight of 500. , the viscosity is 0.26Pa·s.

[0027] The precursor is directly cracked at a high temperature of 1200°C under the protection of high-puri...

Embodiment 2

[0033] In a 1000ml three-neck flask equipped with a stirrer, condenser tube, and nitrogen inlet tube, add 100g of polymethylsilane and 0.8g of diphenylsiloxane, and stir well under the protection of nitrogen, then add CrCl 3 10g, control the flow of nitrogen gas at 300-2000ml / min, after stirring for 3 hours, reduce the speed to about 200-400 rpm, and fully react for about 12-15 hours at 100-150°C. In water, until the gas generated by the airway tube no longer makes the pH test paper turn red, the reaction can be stopped, and the small molecular substances are removed by vacuum filtration, and the obtained liquid substance is chromium-modified polymethylsilane, which is liquid at room temperature. The molecular weight is 800, and the viscosity is 0.36Pa.s. The precursor was directly cracked at a high temperature of 1200°C under the protection of high-purity nitrogen, and its Si / C was 1.09. This material is used as a precursor impregnating agent, and the silicon carbide fiber b...

Embodiment 3

[0039] In a 1000ml three-necked flask equipped with a stirrer, a condenser, and a nitrogen inlet tube, add 100g of polymethylsilane and 0.5g of trifluoroalkylalkylsiloxane, and stir well under the protection of nitrogen, and then add FeCl 34.8g, control the larger nitrogen flow rate of 100-1000ml / min, stir rapidly for 1-2 hours, then reduce the speed to about 300-400 rpm, fully react for about 10-12 hours, the HCl produced by the reaction passes through the airway, and introduces In water, until the gas generated by the airway tube no longer makes the pH test paper turn red, the reaction can be stopped, and the small molecular substances are removed by vacuum filtration, and the obtained liquid substance is iron-modified polymethylsilane, which is liquid at room temperature. The molecular weight is 1000, the viscosity is 0.32Pa.s, the precursor is directly cracked at a high temperature of 1200°C under the protection of high-purity nitrogen, and its Si / C is 1.18. This material ...

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Abstract

The invention discloses a metallic modified polymethyl siloxane, process for preparation and application. The metallic modified polymethyl siloxane regards the polymethyl siloxane as the matrix polymer, metallic chloride as the cross linking agent, oxosilane compound as the accelerant and synthesizes a metallic modified polymethyl siloxane harbinger body polymeric compound via removing hydrochloride which is liquid state in the normal temperature, wherein the mean molecular weight of the metallic modified polymethyl siloxane harbinger body polymeric compound is between 400 and 1000, the ceramic yield is 60-80%, the metallic modified polymethyl siloxane harbinger body polymeric compound can be solidified at 300-400 DEG C, the solidified ceramic yield can achieve more than 95%. The invention can be used for preparing the ceramic group composite material in PIP technology, which can shorten the dipping cycle frequency, reduces the material cost, guarantees the carborundum basal body of the product and has ideal silicon carbide ratio.

Description

technical field [0001] The invention relates to a preparation method and application of metal-modified polymethylsilane, a precursor (impregnating agent) mainly used in the preparation of high-tech ceramic matrix composite materials. Background technique [0002] The "precursor dipping and cracking process" has been successfully used to prepare ceramic matrix composites. Fiber braids need to go through many dipping-curing-cracking treatments to obtain better performance composites. At present, polycarbosilane is the widely used impregnating agent for preparing SiC-based composite materials in the domestic precursor impregnation and cracking process. Chinese patents CN85108006 and CN1031535 disclose synthesis methods of polycarbosilane; Chinese patents CN1251083 and CN1803715 disclose methods for preparing ceramics and composite materials using polycarbosilane as an impregnating agent. However, polycarbosilane has the following disadvantages a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/60C04B35/634
Inventor 李效东邢欣王浩刘琳周新贵胡海峰
Owner NAT UNIV OF DEFENSE TECH
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