Preparation method of boron-containing silicon carbide fiber

A technology of silicon carbide fiber and polycarbosilane, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems that the preparation of boron-containing silicon carbide fiber cannot be replicated or cannot be completely replicated, and achieves non-toxic waste and melt spinning Good performance, simple process and equipment

Active Publication Date: 2015-07-22
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

[0006] The preparation of boron-containing silicon carbide fiber

Method used

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  • Preparation method of boron-containing silicon carbide fiber
  • Preparation method of boron-containing silicon carbide fiber
  • Preparation method of boron-containing silicon carbide fiber

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preparation example Construction

[0029] The boron-containing SiC fiber prepared by boron-containing polycarbosilane in the present invention mainly lies in the synthesis of boron-containing polycarbosilane, and its synthesis method includes:

[0030] (1) The low molecular weight polycarbosilane LPCS has a number average molecular weight of 500-1200 and a molecular weight distribution coefficient of 1.0-1.5.

[0031] (2) Mix dimethyldivinylsilane and borane at a ratio of 3 to 1:1 under nitrogen protection at room temperature, heat to 60°C for 24 hours, then heat up to 120°C for distillation to remove unreacted raw materials, drop The boron-containing monomer can be obtained at room temperature as an oily transparent liquid.

[0032] (3) Under the protection of nitrogen, the above LPCS is dissolved in xylene, and a boron-containing monomer is added, and the weight ratio of the boron-containing monomer to the LPCS is 5% to 20%. Then raise the temperature to 120°C and keep it for 12-24h, then raise the temperatu...

Embodiment 1

[0035]The low molecular weight polycarbosilane LPCS, with a number average molecular weight of 500 and a molecular weight distribution coefficient of 1.0, was dissolved in an equal weight of xylene. (2) Mix dimethyldivinylsilane and borane dimethyl sulfide at a ratio of 1:1 under nitrogen protection at room temperature, heat to 60°C for 24 hours, then heat up to 120°C for distillation to remove unreacted raw materials , the boron-containing monomer can be obtained at room temperature, figure 1 is the infrared spectrum of the boron-containing monomer; (3) under the protection of nitrogen, add the boron-containing monomer to the xylene solution of LPCS, and the weight ratio of the boron-containing monomer to LPCS is 20:100. Then raise the temperature to 120°C and keep it for 24h, then raise the temperature to 250°C and keep it for 6h, then raise the temperature to 350°C and keep it for 4h, then distill at 20Pa for 2h, cool to room temperature to get boron-containing polycarbosil...

Embodiment 2

[0038] The low molecular weight polycarbosilane LPCS, with a number average molecular weight of 960 and a molecular weight distribution coefficient of 1.3, was dissolved in an equal weight of xylene. (2) Mix dimethyldivinylsilane and borane dimethyl sulfide at a ratio of 2:1 under nitrogen protection at room temperature, heat to 75°C for 12 hours, then heat up to 150°C for distillation to remove unreacted raw materials , the boron-containing monomer can be obtained when the temperature is lowered to room temperature. (3) Under the protection of nitrogen, add the boron-containing monomer to the xylene solution of the above LPCS, and the weight ratio of the boron-containing monomer to LPCS is 10:100. Then raise the temperature to 150°C and keep it for 12h, then raise the temperature to 270°C and keep it for 2h, then raise the temperature to 380°C and keep it for 2h, then distill at 100Pa pressure for 1h, cool to room temperature to get boron-containing polycarbosilane.

[0039]...

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Abstract

The invention discloses a preparation method of boron-containing silicon carbide fiber. The preparation method comprises the following steps: mixing dimethyldivinylsilane with borane in a ratio of (3-1): 1 under the protection of nitrogen at room temperature, segmentally heating and preserving heat, and distilling to obtain a boron-containing monomer; dissolving LPCS into dimethylbenzene with weight equal to that of the LPCS, adding the boron-containing monomer, segmentally heating and preserving heat, distilling for 0.5-2 h at 20-100 Pa to remove low molecular compounds, and cooling to room temperature to obtain boron-containing polycarbosilane; putting the boron-containing polycarbosilane into a spinning melting barrel, heating till a uniform melt under the protection of nitrogen, performing melt spinning to obtain continuous fiber, and preparing into unmelted fiber; heating the unmelted fiber to 900-1100 DEG C, ceramizing the unmelted fiber, and further preserving heat at 1400-1800 DEG C. The boron-containing polycarbosilane prepared by the preparation method is not sensitive to air and humidity, has good melt spinning performance, and avoids toxicity of an unmelted boron-containing atmosphere and equipment corrosion caused by the unmelted boron-containing atmosphere.

Description

technical field [0001] The invention belongs to the technical field of high-performance fibers and relates to a method for preparing boron-containing silicon carbide (SiC) fibers. Background technique [0002] SiC fiber is an excellent functional structural material and has broad application prospects in many fields such as aerospace, weaponry and nuclear industry. In the early 1980s, after the commercialization of silicon carbide (SiC) fibers represented by Nicalon, its unique high temperature resistance (1000°C) attracted the attention of the world's technological powers. At present, Japan has realized the industrial production of various SiC fibers and imposed a technical blockade on my country. In China, after more than 30 years of exploration and research, the National University of Defense Technology has independently developed a series of SiC fibers, including KD-I SiC fibers, KD-II SiC fibers, near-stoichiometric SiC fibers and wave-absorbing SiC fibers. The perform...

Claims

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Application Information

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IPC IPC(8): D01F9/10
Inventor 邵长伟王军王浩简科苟燕子王小宙
Owner NAT UNIV OF DEFENSE TECH
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