A kind of preparation method of polyborosilazane with high softening point

A technology of polyborosilazane and high softening point, which is applied in the field of preparation of SiBNC ceramic precursors, can solve the problems of low ceramic yield and achieve the effects of high batch stability, simple process and strong controllability

Active Publication Date: 2015-10-28
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The processability of the precursor prepared by this method is better, but the softening point of the synthesized polyborosilazane is less than 160°C, and the ceramic yield is low

Method used

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  • A kind of preparation method of polyborosilazane with high softening point
  • A kind of preparation method of polyborosilazane with high softening point
  • A kind of preparation method of polyborosilazane with high softening point

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Experimental program
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Effect test

Embodiment 1

[0024] This embodiment includes the following steps:

[0025] (1) Replace nitrogen in the reaction kettle with stirring, temperature measuring, feeding, ventilating, discharging and distillation devices;

[0026] (2) Weigh trichlorosilane, B, B'-dimethylborazine: heptamethyldisilazane molar ratio of 1:0.5:6 Methylborazine, heptamethyldisilazane;

[0027] (3) First add trichlorosilane, B, B'-dimethylborazine to the reactor respectively, and cool the reactor to minus 5°C; then add heptamethyldisilazane at 0.01 liter / min Speed ​​into the reaction kettle, keep stirring;

[0028] (4) After the feeding is completed, heat the reactor to 300°C, and distill at this temperature for 16 hours under atmospheric pressure;

[0029] (5) After the distillation at atmospheric pressure, lower the temperature of the reactor by 50°C, and distill under reduced pressure at this temperature for 1 hour (vacuum degree 0.5kPa), and cool to room temperature to obtain 95g of high softening point polybo...

Embodiment 2

[0035] This embodiment includes the following steps:

[0036] (1) Replace nitrogen in the reaction kettle with stirring, temperature measuring, feeding, ventilating, discharging and distillation devices;

[0037] (2) Weigh trichlorosilane, B, B'-dimethylborazine: heptamethyldisilazane molar ratio of 1:1:6 Methylborazine, heptamethyldisilazane;

[0038] (3) Add trichlorosilane and B, B'-dimethylborazine to the reaction kettle respectively, and cool the reaction kettle to -55°C below zero; then add heptamethyldisilazane at 0.05 liter / Add the reaction kettle at a speed of 1 minute and keep stirring;

[0039] (4) After the feeding is completed, heat the reactor to 250°C, and distill at atmospheric pressure for 25 hours at this temperature;

[0040] (5) After the distillation at atmospheric pressure, lower the temperature of the reactor by 60°C, and distill under reduced pressure at this temperature for 0.3 hours (vacuum degree 0.1kPa), and cool to room temperature to obtain 11...

Embodiment 3

[0043] This embodiment includes the following steps:

[0044] (1) Replace nitrogen in the reaction kettle with stirring, temperature measuring, feeding, ventilating, discharging and distillation devices;

[0045](2) Weigh methylvinylchlorosilane according to the molar ratio of methylvinylchlorosilane: B, B'-diethylborazine: heptamethyldisilazane: 1:1.5:8 Silane, B, B'-diethylborazine, heptamethyldisilazane;

[0046] (3) Add methylvinylchlorosilane and B, B'-diethylborazine to the reactor respectively, and cool the reactor to minus 35°C; then add heptamethyldisilazane at 0.1 The speed of liters / minute is added in the reactor, keep stirring;

[0047] (4) After the feeding is completed, heat the reactor to 300°C, and distill at this temperature for 8 hours under atmospheric pressure;

[0048] (5) After the distillation at atmospheric pressure, lower the temperature of the reactor by 45°C, conduct vacuum distillation for 1 hour (vacuum degree 2kPa), and cool to room temperature...

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Abstract

The invention discloses a preparation method for high softening point polyborosilazane, which comprises the following steps: (1) a reaction still provided with a stirring device, a temperature measurement device, a charging device, a ventilation device, a discharging device, and a distillation device is used for replacement of nitrogen; (2)chlorosilane, dialkyl group borazine and heptamethyldisilazane are weighed according to the molar ratio of 1:(0.5-3):(6-12); (3) chlorosilane, dialkyl group borazine and heptamethyldisilazane are added into the reaction still, and the reaction still is cooled to 5-55 below zero DEG C; the heptamethyldisilazane is added into a reactor at the speed of 0.01-0.2L / min and is stirred; (4) after the charging is completed, the reactor is heated to reach 250-350 DEG C and is distilled for 6-48 hours under the normal pressure; (5) after the distillation under the normal pressure is completed, the temperature of the reactor is reduced by 10-60 DEG C and is subjected to reduced pressure distillation for 0.3-3 hours. The softening point of polyborosilazane is synthesized by the method is greater than 180 DEG C, the ceramic yield is more than 60 percent, and high performance ceramic fiber and ceramic matrix can be prepared.

Description

technical field [0001] The invention relates to a preparation method of polyborosilazane with a high softening point, in particular to a preparation method of a SiBNC ceramic precursor. Background technique [0002] SiBNC ceramics have excellent high temperature oxidation resistance and high temperature creep resistance, and have important application prospects in aviation, aerospace, weapons, ships and other fields. Due to the characteristics of the material itself, it is difficult to synthesize it by inorganic methods. Precursor conversion method is the most effective preparation method of this kind of ceramic materials. [0003] At present, the preparation methods of SiBNC ceramic precursors mainly include polymer route and monomer route. [0004] The polymer route refers to modifying polysilazane and other polymers containing Si-N bonds with boron-containing compounds and obtaining side groups as Si-B-N-C precursors containing B groups (Chem.Mater, 2002, 14: 3398; Che...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G77/62C04B35/58
Inventor 邵长伟王浩王军宋永才王应德简科苟燕子
Owner NAT UNIV OF DEFENSE TECH
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