Preparation method for liquid polyborosilazane

A technology of polyborosilazane and polysilazane, which is applied in the field of preparation of liquid polyborosilazane, can solve the problems of lack of fluidity and preparation of SiBCN ceramic matrix composite materials, etc., to improve high temperature oxidation resistance, The synthesis process is simple and the effect of good fluidity

Inactive Publication Date: 2011-07-06
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the above studies, although polyborosilazane can be prepared through the polymer route, because each H 3 The B molecule contains 3 boron-hydrogen bonds, and it is easy to over-crosslink during the boro-hydrogen addition process, so that polyborosilazane is solid at room temperature, does not have good fluidity, and cannot be directly used for polymer impregnation Preparation of SiBCN Ceramic Matrix Composites by Cracking Method

Method used

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  • Preparation method for liquid polyborosilazane
  • Preparation method for liquid polyborosilazane
  • Preparation method for liquid polyborosilazane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 1) Under the protection of an inert atmosphere, weigh 10 g of vinyl liquid polysilazane, put it into a Schlenk reaction bottle, and in a nitrogen atmosphere, distill xylene through sodium-benzophenone to remove water, and then distill the resulting Xylene 5.0g is transferred in the Schlenk reaction flask, stirs to obtain the mixed solution;

[0023] 2) Under the protection of an inert atmosphere, add 1 g of 9-borabicyclo[3,3,1]nonane into the mixed solution obtained in step 1);

[0024] 3) In a 50°C oil bath, the reaction was continuously stirred for 24 hours;

[0025] 4) After the reaction was completed, xylene was removed by distillation under reduced pressure to obtain 10.4 g of liquid polyborosilazane.

[0026] The average structural formula of the raw material liquid polysilazane used is [SiH(CH=CH 2 ) 0.24 (CH 3 ) 0.76 NH] n , measure its molecular weight and molecular weight distribution thereof by gel permeation chromatography (GPC), eluent is tetrahydrofu...

Embodiment 2

[0028] 1) Under the protection of an inert atmosphere, weigh 10 g of vinyl liquid polysilazane, put it into a Schlenk reaction bottle, and in a nitrogen atmosphere, distill toluene through sodium-benzophenone to remove water, and then distill 20 g of the obtained toluene Transfer to the Schlenk reaction bottle, stir the mixed solution;

[0029] 2) Under the protection of an inert atmosphere, add 5 g of 9-borabicyclo[3,3,1]nonane into the mixed solution obtained in step 1);

[0030] 3) After the dropwise addition is completed, keep stirring and reacting for 6 hours in an ice-salt bath at -10°C;

[0031] 4) After the reaction was completed, the toluene was removed by distillation under reduced pressure to obtain 13.9 g of liquid polyborosilazane.

[0032] The average structural formula of the raw material liquid polysilazane used is [SiH 0.77 (CH 3 )(CH=CH 2 ) 0.23 NH] n , measure its molecular weight and its molecular weight distribution by gel permeation chromatography (...

Embodiment 3

[0034] 1) Under the protection of an inert atmosphere, weigh 10 g of n-butynyl liquid polysilazane, put it into a Schlenk reaction bottle, and in a nitrogen atmosphere, distill ether through sodium-benzophenone to remove water, and then distill the obtained Diethyl ether 30g was transferred to the Schlenk reaction flask, and stirred to obtain a mixed solution;

[0035] 2) Under the protection of an inert atmosphere, add 10 g of 9-borabicyclo[3,3,1]nonane into the mixed solution obtained in step 1);

[0036] 3) In a liquid nitrogen acetone bath at -78°C, continue to stir and react for 10 hours;

[0037] 4) After the reaction was completed, diethyl ether was removed by distillation under reduced pressure to obtain 19.3 g of liquid polyborosilazane.

[0038] The average structural formula of the raw material liquid polysilazane used is [SiH 1.35 (CH 2 CH 2 C≡CH) 0.2 (CH 3 ) 0.45 NH] n , measure its molecular weight and its molecular weight distribution by gel permeation c...

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Abstract

The invention relates to a preparation method for liquid polyborosilazane and belongs to the field of inorganic nonmetallic materials. The preparation method comprises the following steps: liquid polyborosilazane and 9-borabicyclo [3,3,1]-nonane are added in a solvent in inert atmosphere to obtain mixed solution, then the obtained mixed solution is hydroborated under the stirring condition, and then the solvent is removed after completion of hydroboration to obtain the liquid polyborosilazane. The preparation method solves the problems in the traditional polymer route that excessive cross-linking is easily caused in the hydroboration addition reaction, and solid polyborosilazane has poorer fluidity. The prepared liquid polyborosilazane has good fluidity and high ceramic yield and can be directly used for the high polymer infiltration and pyrolysis method for preparing SiBCN ceramic matrix composites.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a preparation method of liquid polyborosilazane. Background technique [0002] Silicon carbide ceramic matrix composites toughened by continuous fibers have excellent high temperature resistance and mechanical properties, and are often prepared by polymer impregnation cracking method (1, Interrante L V, Jacobs J M, Sherwood W, et al.Fabrication and properties of fiber-and particulate-reinforced SiC matrix composites obtained with (A)HPCS as the matrix source[J]. Key Engineering Materials, 1997, 127: 271-278), the basic process includes: the liquid polymer or polymer as the precursor The fiber preform is impregnated with a solution or melt, and after cross-linking and solidification, it is cracked at a high temperature under the protection of an inert atmosphere. In order to increase the density of the composite material, multiple cycles of dipping and cracking are ge...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G77/62C04B35/515
Inventor 余兆菊周聪李然詹俊英杨乐涂惠彬廖志楠何国梅夏海平陈立富张立同
Owner XIAMEN UNIV
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