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Preparation method of low oxygen content silicon carbide fiber prepared from thermally curable polycarbosilane

A technology of silicon carbide fiber and polycarbosilane, which is applied to the chemical characteristics of fibers, textiles and papermaking, etc., can solve the problems of complex procedures and difficulty in meeting large-scale production, and achieve the effect of simple process and low cost

Active Publication Date: 2020-12-29
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires polycarbosilane to be graded, and the procedure is complicated, and it is difficult to meet large-scale production (W.Toreki, C.D.Batich, M.D.Sacks, et al. Polymer~Derived Silicon Carbide Fibers with Improved ThermomechanicalStability [J]. Mrs Proceedings, 1992, 271:761~769. Preparation of silicon carbide fiber with low oxygen content by dry spinning method, Peng Shanyong, master thesis)

Method used

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  • Preparation method of low oxygen content silicon carbide fiber prepared from thermally curable polycarbosilane
  • Preparation method of low oxygen content silicon carbide fiber prepared from thermally curable polycarbosilane
  • Preparation method of low oxygen content silicon carbide fiber prepared from thermally curable polycarbosilane

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Experimental program
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Embodiment 1

[0050] The preparation process of silicon carbide fibers with low oxygen content is as follows:

[0051] (1) Preparation of PVCS

[0052] The PCS used for spinning is used as a precursor, and the PCS is a polycarbosilane synthesized by cracking and rearranging polydimethylsilane, with a softening point of 210-230°C and a number-average molecular weight of 1650-1900.

[0053] This PCS and dimethyl divinyl silane (DVS) are added in the autoclave by the mass ratio of 1:0.3, add xylene in the ratio of 10ml / g by xylene / PCS and evenly miscible, then with chloroplatinic acid / PCS is 100ppm and chloroplatinic acid is added as a catalyst. After vacuuming and replacing high-purity argon, the argon pressure is pre-filled to 11MPa, and then heated to 120°C. After 20 hours of heat preservation, the reaction is stopped, and the product solution is cooled to room temperature. Put it in a distillation device, under the protection of high-purity argon, raise the temperature to 80°C and distil...

Embodiment 2

[0066] The preparation process of silicon carbide fibers with low oxygen content is as follows:

[0067] (1) Preparation of PVCS

[0068] The PCS used for spinning is used as a precursor, and the PCS is a polycarbosilane synthesized by cracking and rearranging polydimethylsilane, with a softening point of 210-230°C and a number-average molecular weight of 1650-1900.

[0069] Add the PCS and methyltrivinylsilane (TVS) into the reaction vessel at a mass ratio of 1:0.3, add xylene at a ratio of 15ml / g to xylene / PCS, and then mix it with chloroplatinic acid / PCS Add chloroplatinic acid as a catalyst at a ratio of 150ppm, vacuumize and replace high-purity argon, heat to 90°C while stirring under normal pressure and high-purity argon protection conditions, stop the reaction after 20 hours of heat preservation, and cool to room temperature The product solution is placed in a distillation device, and under the protection of high-purity argon, the temperature is raised to 60-100° C. an...

Embodiment 3

[0081] The preparation process of silicon carbide fibers with low oxygen content is as follows:

[0082] (1) Preparation of PVCS

[0083] The PCS used for spinning is used as a precursor, and the PCS is a polycarbosilane synthesized by cracking and rearranging polydimethylsilane, with a softening point of 210-230°C and a number-average molecular weight of 1650-1900.

[0084] This PCS and dimethyl divinyl silane (DVS) are added in the autoclave by the mass ratio of 1:0.5, add xylene in the ratio of 20ml / g by xylene / PCS and evenly miscible, then with chloroplatinic acid / The proportion of PCS is 100ppm and chloroplatinic acid is added as a catalyst. After vacuuming and replacing high-purity nitrogen, the pressure of argon gas is prefilled to 11MPa, and then heated to 120°C. After 20 hours of heat preservation reaction, the reaction is stopped. In the distillation device, under the protection of high-purity argon, the temperature is raised to 60-100° C. and the solvent and unrea...

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Abstract

The invention discloses a preparation method for preparing low-oxygen-content silicon carbide fiber from heat-curable polycarbosilane. The preparation method comprises the following steps: synthesizing vinyl-containing polycarbosilane with a heat curing property from polycarbosilane and vinyl-containing silane through a hydrosilylation reaction, then performing dry spinning to obtain raw polycarbosilane fiber with the heat curing property, then thermally treating the raw polycarbosilane fiber to achieve crosslinking curing of the fiber, and finally performing high-temperature pyrolysis to obtain the silicon carbide fiber. The preparation method is simple and relatively low in cost; with the preparation method, the prepared silicon carbide fiber has the diameter of 5-20 microns, the oxygencontent lower than 1wt%, and the tensile retention rate of 50% or above 50% after treatment for 1h at 1600 DEG C in an inert atmosphere.

Description

technical field [0001] The invention belongs to the technical field of ceramic fibers, in particular to a method for preparing silicon carbide fibers with low oxygen content by using heat-curable polycarbosilane. Background technique [0002] Silicon carbide (SiC) fiber has excellent high temperature resistance and corrosion resistance, and is an important part of ceramic matrix composites. [0003] Among the many preparation methods of silicon carbide fibers, the precursor pyrolysis conversion method pioneered by Professor Yajima of Japan is the only commercial preparation method. It mainly includes four processes: precursor synthesis, spinning, non-melting treatment and high temperature pyrolysis. For example, typical Nicalon fibers are prepared from polycarbosilane (PCS) as a precursor through melt spinning, air infusion and pyrolysis processes. [0004] However, studies have shown that: in the process of air not melting, a large amount of oxygen is introduced into the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D01F9/10
CPCD01F9/10
Inventor 顾喜双何流黄庆袁钦
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI