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Method for preparing silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane

A technology of polycarbosilane and foam ceramics, which is applied in the field of ceramic foam, can solve problems such as unfavorable environmental protection, rare research, and technology that is yet to be developed, and achieves a product that is beneficial to environmental protection, simple in the preparation process, and excellent in temperature resistance Effect

Active Publication Date: 2019-11-22
福建立亚化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The above decomposition reactions lead to damage to the strength of the foam ceramic skeleton, limiting the use temperature of silicon carbide foam ceramics below 600 °C
[0006] Summary of existing technologies: Silicon carbide particles, binder and solvent are used to make a slurry, and organic matter with a foam structure is used as a template. After impregnation, sintering is carried out at about 1300 ° C, but the disadvantage is obvious: the uniformity of the slurry is difficult to guarantee , the use of solvents in the preparation process is not conducive to environmental protection; using organosilane compound polycarbosilane as the precursor, the preparation of foam ceramics by the precursor method is rare in this part of the research, and the technology is yet to be developed

Method used

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  • Method for preparing silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane
  • Method for preparing silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The preparation process of silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane is as follows:

[0037] (1) Preparation of heat-curable polycarbosilane, one of the raw materials

[0038] Preparation of heat-curable polycarbosilane, refer to (Gu Xishuang, Song Yongcai. Synthesis and properties of heat-curable polycarbosilane [J]. Silicone Materials, 2015,29(6):462-468.): Polycarbosilane (commercially available, molecular weight 2800, softening point 220°C, molecular weight 1700) dissolved in xylene and dimethyldivinylsilane (commercially available) at a mass ratio of 1:1, placed in an autoclave, added platinum catalyst, pumped Replace the high-purity nitrogen with vacuum, increase the pressure to 12.5MPa; then heat up to 110°C under the protection of high-purity nitrogen to react for 30h; cool, and distill under reduced pressure to obtain the solid product PVCS.

[0039] It has been characterized that the amount of vinyl in heat-curable polyc...

Embodiment 2

[0049] The preparation process of silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane is as follows:

[0050] (1) Preparation of heat-curable polycarbosilane, one of the raw materials

[0051] Preparation of heat-curable polycarbosilane, refer to (Gu Xishuang, Song Yongcai. Synthesis and properties of heat-curable polycarbosilane [J]. Silicone Materials, 2015,29(6):462-468.): Polycarbosilane (commercially available, molecular weight 2800, softening point 240°C, molecular weight 1900) dissolved in xylene and dimethyldivinylsilane (commercially available) at a mass ratio of 1:1, placed in an autoclave, added platinum catalyst, pumped Replace the high-purity nitrogen with vacuum, increase the pressure to 12.5MPa; then heat up to 110°C under the protection of high-purity nitrogen to react for 30h; cool, and distill under reduced pressure to obtain the solid product PVCS.

[0052] It has been characterized that the amount of vinyl in heat-curable polyc...

Embodiment 3

[0062] The preparation process of silicon carbide foam ceramics with heat-curable polycarbosilane and polyurethane is as follows:

[0063] (1) The heat-curable polycarbosilane prepared in Example 1 was used.

[0064] (2) Grinding raw materials

[0065] The mass ratio, PVCS: polyurethane is 1:0.6, at 30°C, in an argon atmosphere, fully mix and grind the above two materials to obtain a uniformly mixed powder.

[0066] (three) shaping

[0067] The powder is added into the mold, and the internal shape is cylindrical, and a pressure of 0.3Mpa is applied to discharge the gas inside the powder to obtain a foam preform.

[0068] (4) Heat treatment of organic foam preform

[0069] Put the organic foam preform into the furnace, and replace the high-purity nitrogen with vacuum for three times, then raise the temperature of the organic foam to 220°C at a rate of 2°C / min in an argon atmosphere, and keep it warm for 6 hours.

[0070] (5) Preparation of silicon carbide-aluminum carbide f...

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Abstract

The invention discloses a method using heat-curable polycarbosilane and polyurethane to prepare silicon carbide foamed ceramic. The method includes: sufficiently grinding and evenly mixing the heat-curable polycarbosilane and the polyurethane, adding into a die, applying certain pressure, and discharging gas inside powder to obtain a preform; subjecting the foamed preform to heat treatment to achieve self-crosslinking-curing of the polycarbosilane, and performing high-temperature pyrolysis in argon atmosphere to obtain the foamed ceramic. The preparation method has the advantages that the method is simple, few in process procedures, low in cost, capable of avoiding the use of solvents and beneficial to environment protection, the shrinkage rate of the foamed ceramic prepared by the methodis smaller than 10%, the volume density of the foamed ceramic prepared by the method is smaller than 0.6g / cm<3>, the porosity of the foamed ceramic prepared by the method is 60-90%, the rupture strength of the foamed ceramic prepared by the method reaches 1.0-2.6MPa, and the foamed ceramic prepared by the method can be used under 1200-1400 DEG C for a long time.

Description

technical field [0001] The invention belongs to the technical field of ceramic foam, and in particular relates to a method for preparing silicon carbide foam ceramics from heat-curable polycarbosilane and polyurethane. Background technique [0002] The traditional preparation process of silicon carbide foam ceramics is complicated. It mainly blends silicon carbide powder with dispersant, sintering aid, etc. to make a slurry, and then impregnates it with an organic foam template to obtain a preform. The preform is dried and organic matter is excluded. The process is fired to obtain silicon carbide foam ceramics. (Liang Hanqin, Yao Xiumin, Huang Zhengren, Liu Xuejian. Liquid phase formation process during liquid phase sintering of silicon carbide ceramics[J]. Mechanical Engineering Materials, 2015,39(02):34-37.;) Liang Hanqin studied SiC foam ceramics Sintering mechanism: SiC foam ceramics is mainly due to the coating and connection of glass to SiC particles and the formation...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/571C04B35/622C04B38/06
CPCC04B35/571C04B35/622C04B38/067C04B2235/6562C04B2235/6567C04B2235/77C04B2235/96C04B38/0074C04B38/0058C04B38/0067
Inventor 顾喜双高锦荣
Owner 福建立亚化学有限公司