High temperature high pressure synthesis method for polycarbosilane

A technology of polycarbosilane and a synthesis method, which is applied in the field of high temperature and high pressure synthesis of polycarbosilane, can solve the problems of low Si-H bond content, low yield of synthetic PCS, low molecular weight of PCS, etc., so as to shorten the reaction time and increase the reaction pressure. , the effect of increasing the reaction rate

Inactive Publication Date: 2005-01-26
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

Research in the past 20 years has shown that the synthesis time of this method is long (>48h), the yield of synthetic PCS

Method used

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  • High temperature high pressure synthesis method for polycarbosilane
  • High temperature high pressure synthesis method for polycarbosilane

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Example Embodiment

[0013] The present invention will be further described below in conjunction with embodiment.

[0014] (1) Using PDMS as the embodiment of high temperature and high pressure synthesis of PCS

[0015] Put 250g of PDMS in the autoclave, repeatedly vacuumize and replace the gas in the autoclave with high-purity nitrogen, and finally add 0.5Mpa of N 2 , sealed; then the temperature was programmed to 450 ° C, reacted for 6h, and after cooling, the crude product of PCS was obtained. The crude product was dissolved in xylene, filtered, and the filtrate was distilled under reduced pressure at 350° C., and the PCS precursor (PCS-HP) in the form of brownish yellow resin was obtained after cooling.

[0016] The following is an evaluation of the present invention based on the composition structure, Si-H bond content, yield, molecular weight and other characteristics of PCS-HP, and compared with the characteristics of PCS-NP synthesized at normal pressure with a similar softening point.

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Abstract

The invention provides a high temperature high pressure synthesis method for polycarbosilane which comprises the steps of, (1) loading small molecular PCS or LPS whose PDMS or average molecular weight is less than 2000 into hot pressing kettle, evacuating and replacing gas in the kettle with high purity nitrogen, charging 0.1-5Mpa of N2 and sealing, elevating the temperature to 430-490 deg. C, reacting time being 0.5-10 hours, (3) dissolving the crude product with xylene, filtering, and proceeding vacuum distillation to the filter liquor at 330-380 deg. C, finally cooling down to obtain the resin form product.

Description

technical field [0001] The invention relates to a synthesis method of polycarbosilane, in particular to a synthesis method of polycarbosilane under high temperature and high pressure. Background technique [0002] At present, the preparation method of SiC fiber is mainly the transformation method of organic precursor. This method includes the synthesis of organic precursor polycarbosilane (Polycarbosilane, PCS), melt spinning, non-melting and high-temperature firing and other processes. PCS is the key material for the preparation of SiC fibers by the conversion method of organic precursors. The synthesis of PCS precursors is the basis of all research work. Its composition, structure and key physical and chemical properties play a very important role in determining the performance of SiC fibers. The performance of the PCS precursor not only directly affects the melt spinning process and the quality of the precursor, but also affects the non-melting ...

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Application Information

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IPC IPC(8): C08G77/60
Inventor 程祥珍谢征芳宋永才肖加余
Owner NAT UNIV OF DEFENSE TECH
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