Preparation method for SiBN(C) ceramic fiber precursor

A ceramic fiber and precursor technology, which is applied in the field of preparation of ceramic fiber materials, can solve problems such as constraints, and achieve the effect of simple operation and easy access to raw materials

Inactive Publication Date: 2013-10-09
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the natural brittleness of the Si-B-N framework, local crosslinking and the existence of a ring-shaped rigid structure, the SiBN(C) ceramic fiber precursor exhibits

Method used

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  • Preparation method for SiBN(C) ceramic fiber precursor
  • Preparation method for SiBN(C) ceramic fiber precursor
  • Preparation method for SiBN(C) ceramic fiber precursor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] (1) Put the anhydrous toluene solution of the precursor molecules in a reaction vessel with a stirring and distillation device, heat to 120°C to remove the toluene solvent, and after the solvent is distilled, heat up to 150°C for pre-polymerization to a certain degree of polymerization , with an average molecular weight of 600; (2) Add 6% hydroxyl-terminated polydimethylsiloxane (molecular weight about 500) to the reaction system, and polymerize at 160°C for 40 hours to obtain a copolymerized modified polysiloxane Boron nitrogen precursor polymer; (3) Put the polysilicon boron nitrogen precursor polymer in the melt spinning equipment for vacuum defoaming for 4 hours, under the conditions of temperature 130 ℃, pressure 5 MPa, winding speed 450m / min A SiBN(C) ceramic fiber precursor with a diameter of 20 μm was prepared by melt spinning, and the precursor had good flexibility.

Embodiment 2

[0030] (1) Put the toluene solution of the precursor molecules in a reaction vessel with a stirring and distillation device, heat to 130°C to remove the toluene solvent, and after the solvent is distilled, raise the temperature to 140°C for pre-polymerization to a certain degree of polymerization, The average molecular weight is 2300;

[0031] (2) Add bis(3-aminopropyl) end-capped polydimethylsiloxane (molecular weight about 2500) with a mass fraction of 3% to the reaction system, and polymerize at 180°C for 30 hours to obtain a copolymerized modified polydimethylsiloxane. Silicon boron nitrogen precursor polymer; (3) Put the polysilicon boron nitrogen precursor polymer in the melt spinning equipment for vacuum degassing for 6 hours, under the conditions of temperature 125 ℃, pressure 8MPa, winding speed 250m / min A SiBN (C) ceramic fiber precursor with a diameter of 27 μm was prepared by melt spinning under the lower pressure, and the precursor had good flexibility.

Embodiment 3

[0033](1) Put the toluene solution of the precursor molecules in a reaction vessel with a stirring and distillation device, heat to 125°C to remove the toluene solvent, and after the solvent is distilled, raise the temperature to 130°C for pre-polymerization to a certain degree of polymerization; (2) Add hexamethylenediamine with a mass fraction of 1% to the reaction system, and polymerize at 170°C for 32 hours to obtain a copolymerized modified polysilicon boron nitrogen precursor polymer; (3) polymerize the polysilicon boron nitrogen precursor The material was placed in a melt spinning equipment for vacuum defoaming for 5 hours, and the SiBN (C) ceramic fiber precursor with a diameter of 35 μm was obtained by melt spinning under the conditions of a temperature of 135 ° C, a pressure of 9 MPa, and a winding speed of 175 m / min. The precursor has good flexibility.

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Abstract

The invention relates to a preparation method for a SiBN(C) ceramic fiber precursor. The preparation method comprises the steps of synthesizing SiBN(C) ceramic fiber precursor molecules by using methyl dichlorosilane (MeHSiCl2), hexamethyl disilazane (HMDZ), boron trichloride (BCl3) and methylamine (CH3NH2) at a temperature ranging from-40 DEG C to-80 DEG C; removing toluene from an anhydrous toluene solution of the SiBN(C) ceramic fiber precursor molecules; heating to a temperature of 130-300 DEG C to obtain a prepolymer; then adding active group-terminated polydimethylsiloxane or active group-terminated long carbon chain molecules; keeping for 10-100 h at the temperature of 130-300 DEG C; defoaming and melt-spinning. Aiming at the problems of large friability, low strength and the like of the SiBN(C) ceramic fiber precursor, the SiBN(C) ceramic fiber precursor with excellent flexibility is prepared by employing a copolymerization method, thereby providing a foundation for continuous and integrated preparation of SiBN(C) ceramic fibers.

Description

technical field [0001] The invention belongs to the field of preparation of ceramic fiber materials, in particular to a preparation method of a SiBN (C) ceramic fiber precursor. Background technique [0002] SiBN(C) ceramic fiber combines Si 3 N 4 And the excellent characteristics of BN fiber, with its light weight, high strength, high temperature resistance, corrosion resistance, creep resistance, high temperature oxidation resistance, good thermal stability and good dielectric properties, it has broad application prospects in the fields of national defense and aerospace. [0003] The organic polymer precursor method has unique advantages in the preparation of SiBN(C) ceramic fibers, which are reflected in the controllability of the component ratio and the designability of the molecular structure, which is conducive to industrial production. This method can generally be divided into four major steps: synthesis of precursor polymer, melt spinning, non-melting treatment of ...

Claims

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Application Information

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IPC IPC(8): C04B35/515C04B35/622
Inventor 余木火胡建建韩克清牟世伟唐彬彬贾军孙泽玉邱显星杨燕平王会峰耿冉柯盛包
Owner DONGHUA UNIV
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