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Preparation method of liquid-state polycarbosilane

A polycarbosilane, liquid technology, applied in the field of preparation of liquid polycarbosilane, can solve the problems of limiting the large-scale preparation and application of liquid polycarbosilane, difficult control of the reaction process, difficult operation, etc. The effect of low carbon content and improved safety

Active Publication Date: 2019-03-19
AEROSPACE RES INST OF MATERIAL & PROCESSING TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Using LiAlH 4 There are some disadvantages in the reduction method: (1) LiAlH 4 Expensive; (2) LiAlH 4 It is extremely active, the reaction process is difficult to control, the risk is high, and the operation is difficult; these problems limit the large-scale preparation and application of liquid polycarbosilane

Method used

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  • Preparation method of liquid-state polycarbosilane
  • Preparation method of liquid-state polycarbosilane
  • Preparation method of liquid-state polycarbosilane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] (1) Add 184 grams of chloromethyltrichlorosilane and 282 grams of hexamethyldisilazane to the Schlenk reactor filled with an inert gas atmosphere in advance, and stir to mix the raw materials uniformly, then raise the temperature to 50 ° C, stir And react for 12 hours;

[0033] (2) Add 28 grams of activated magnesium chips into the purified and dried tetrahydrofuran, and add the material obtained in step (1), 7.6 grams of allyl chloride and 200 mL of tetrahydrofuran through a dropping funnel. After stirring for 1 hour, a mixed solution of 16.3 g of chloromethylmethyldichlorosilane and 100 mL of tetrahydrofuran was added to the system using a dropping funnel, and the temperature of the system was raised to 60° C., stirred and reacted for 12 hours.

[0034] (3) Add 19 grams of sodium borohydride, and the reaction temperature is 60°C. Stir for 12 hours after addition of sodium borohydride is complete.

[0035](4) Add petroleum ether, deionized water and concentrated hydr...

Embodiment 2

[0040] (1) Add 184 grams of chloromethyltrichlorosilane and 241.5 grams of hexamethyldisilazane into a Schlenk reactor filled with an inert gas atmosphere in advance, and stir to mix the raw materials uniformly, then raise the temperature to 50 ° C, and stir And react for 12 hours;

[0041] (2) Add 28 grams of activated magnesium chips into the purified and dried tetrahydrofuran, and add the material obtained in step (1), 7.6 grams of allyl chloride and 200 mL of tetrahydrofuran through a dropping funnel. After stirring for 1 hour, a mixed solution of 16.3 g of chloromethylmethyldichlorosilane and 100 mL of tetrahydrofuran was added to the system using a dropping funnel, and the temperature of the system was raised to 60° C., stirred and reacted for 12 hours.

[0042] (3) Add 19 grams of sodium borohydride, and the reaction temperature is 60°C. Stir for 12 hours after addition of sodium borohydride is complete.

[0043] (4) Add petroleum ether, deionized water and concentrat...

Embodiment 3

[0046] (1) Add 184 grams of chloromethyltrichlorosilane and 282 grams of hexamethyldisilazane to the Schlenk reactor filled with an inert gas atmosphere in advance, and stir to mix the raw materials uniformly, then raise the temperature to 50 ° C, stir And react for 12 hours;

[0047] (2) Add 28 grams of activated magnesium chips into the purified and dried tetrahydrofuran, and add the material obtained in step (1), 7.6 grams of allyl chloride and 200 mL of tetrahydrofuran through a dropping funnel. After stirring for 1 hour, a mixed solution of 14 g of chloromethylmethylchlorosilane and 100 mL of tetrahydrofuran was added to the system using a dropping funnel, and the temperature of the system was raised to 60° C., stirred and reacted for 12 hours.

[0048] (3) Add 19 grams of sodium borohydride, and the reaction temperature is 60°C. Stir for 12 hours after addition of sodium borohydride is complete.

[0049] (4) Add petroleum ether, deionized water and concentrated hydroch...

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Abstract

The invention relates to a preparation method of liquid-state polycarbosilane. The preparation method includes: subjecting hexamethyl disilazane and chloromethyl trichlorosilane to partial ammonolysis, being in format coupling reaction with unsaturated chloroalkane and chloromethyl chlorosilane, adding a certain amount of NaBH4 (sodium borohydride) reductant for reduction after reaction is completed, adding petroleum ether, deionized water and concentrated hydrochloric acid into an obtained material for acid pickling and extraction, adopting NaOH to dry an obtained petroleum ether solution, filtering, and adopting a method of reduced pressure distillation to evaporate the petroleum ether out to obtain flavescent thick liquid which is liquid-state polycarbosilane. Liquid-state polycarbosilane prepared by the method is high in fluidity and processability and can be directly in thermal polymerization, and ceramic yield is higher than 70%. Content of free carbon in ceramic is low, SiC ceramic phase is high in purity, and liquid-state polycarbosilane is suitable for serving as a high-performance SiC ceramic precursor, can be used for ultrahigh-temperature ceramic based composite material soaking substrates and can also be used for preparing high-performance materials like SiC ceramic coatings and fiber.

Description

technical field [0001] The invention relates to a preparation method of liquid polycarbosilane, which belongs to the technical field of preparation of inorganic non-metallic materials. Background technique [0002] Continuous fiber toughened SiC ceramic composites have excellent physical and mechanical properties, and are considered to be the most promising materials in the aerospace field in the 21st century. In 1975, Yajima used solid organopolymer polycarbosilane (PCS) as a precursor, successfully prepared SiC ceramic fibers through steps such as spinning, non-melting treatment, and high-temperature cracking, and opened up a precursor conversion method to prepare high-performance ceramic fibers. New frontiers in ceramics. Over the past 30 years, PCS, as the precursor of SiC ceramics, has been intensively studied. In recent years, a liquid hyperbranched PCS (hyperbranched PCS, HBPCS), which has attracted great interest from researchers because of its good fluidity, self-...

Claims

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Application Information

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IPC IPC(8): C08G77/60
CPCC08G77/60
Inventor 冯志海胡继东陶孟李媛田跃龙许艺芬
Owner AEROSPACE RES INST OF MATERIAL & PROCESSING TECH
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