CN1298767C - High temperature high pressure synthesis method for polycarbosilane - Google Patents
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- CN1298767C CN1298767C CNB2004100231854A CN200410023185A CN1298767C CN 1298767 C CN1298767 C CN 1298767C CN B2004100231854 A CNB2004100231854 A CN B2004100231854A CN 200410023185 A CN200410023185 A CN 200410023185A CN 1298767 C CN1298767 C CN 1298767C
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Abstract
The present invention discloses a high-temperature and high-pressure synthetic method for carbon gathering silicane, which comprises the following steps: (1), small molecule PCS or LPS whose PDMS or weight average molecular weight is approximately smaller than 2000 is arranged in an autoclave, vacuum is pumped repeatedly, gas in the autoclave is displaced by purity nitrogen and finally, the autoclave is pre-added with 0.1 to 5MPa of N2 and is sealed; (2), temperature is raised by a program to 430 to 490 DEG C for reacting 0.5 to 10h; (3), coarse products obtained in the step (2) are dissolved and filtered by xylene, an obtained filtered solution is pressure reduced and distilled under 330 to 380 DEG C and after cooling, resin type PCS precursors are obtained. The present invention has the following advantages (1), reaction rates are enhanced, the molecular weight of the precursors is increased and synthesis yield is enhanced; (2), equipment is simplified, and the needed equipment is only a high-pressure reaction vessel; (3), processing control is simplified, and process parameters only comprise reaction temperature, reaction time and pre-added pressure; (4) the quantity of reactants can be accurately introduced, which enables the reaction process to be simplified. The present invention is particularly suitable for preparing precursors containing different elements, such as B, Al, Fe, etc.
Description
Technical field
The present invention relates to a kind of synthetic method of Polycarbosilane, relate in particular to a kind of Polycarbosilane High Temperature High Pressure synthetic method.
Background technology
The SiC fiber preparation method mainly is the organic precursor method conversion method at present.This method comprises that (Polycarbosilane, does not melt and high temperature such as burns till at operation synthetic, melt-spinning PCS) the organic precursor method Polycarbosilane.PCS is the critical material that the organic precursor method conversion method prepares the SiC fiber, and the synthetic of PCS precursor is the basis of full-fledged research work, and the physics-chem characteristic of its composition, structure and key has crucial decisive action for the performance of SiC fiber.The performance of PCS precursor not only directly influences the quality of melt-spinning process and precursor, also influences the not thaw process of precursor, thus composition, structure, performance that fiber is burnt till in final influence.Therefore, synthesizing of PCS precursor has very important effect in the preparation of SiC fiber.
At present, the precursor legal system is equipped with the SiC fiber, the synthetic PCS precursor of constant-pressure and high-temperature cracking processs that adopt promptly at first are being cracked into liquid polysilane (LPS) with polydimethyl silane (PDMS) more more than 360 ℃, make LPS change PCS under 450～470 ℃ of atmospheric pressure states then.Nearly 20 years studies show that, the long (＞problem such as 48h), synthetic PCS yield is low, and synthetic PCS exists molecular weight low, and softening temperature is low, and the Si-H linkage content is low of this method generated time.
Summary of the invention
The objective of the invention is to overcome the defective of above-mentioned prior art, a kind of yield height, molecular weight height, softening temperature height, Polycarbosilane (PCS) precursor synthetic method that the Si-H linkage content is high are provided.
Further purpose of the present invention is to provide a kind of not only yield height, molecular weight height, Si-H linkage content height, and good uniformity, the PCS precursor synthetic method that foreign matter content is few.
For realizing first purpose of the invention described above, the present invention has adopted following technical proposals: with polydimethyl silane (PDMS) or weight-average molecular weight is raw material less than 2000 small molecules PCS approximately, under high pressure-temperature, react, change the PCS that processing parameter (temperature of reaction, reaction times, precharge pressure etc.) can synthesize different softening point.
For realizing second purpose of the invention described above, it is raw material that the present invention selects liquid polysilane (LPS) for use, reacts the PCS of synthetic different softening point under high pressure-temperature.
The present invention specifically comprises following operation steps: (1) places PDMS or weight-average molecular weight in the autoclave less than 2000 small molecules PCS or LPS approximately (when the needs preparation contains the PCS precursor of different elements such as B, Al, Fe, also should add the compound that contains elements such as B, Al, Fe that is equivalent to these raw material weights 2-10wt%; When needs prepare rich carbon PCS precursor, also should add the compounds such as polyvinyl chloride that are equivalent to these raw material weights 1-10wt%), vacuumize repeatedly and replace gas reactor with high pure nitrogen, finally add the N of 0.1～5Mpa in advance
2, sealing; (2) temperature programming to 430 then～490 ℃, reaction 0.5～10h promptly gets the thick product of PCS after the cooling; (3) should thick product through xylene soluble, filtration, filtrate is carried out underpressure distillation at 330～380 ℃, promptly gets arborescens PCS precursor after the cooling.Be the synthetic PCS of raw material with PDMS or LPS wherein, preferred reaction conditions is: adding nitrogen pressure in advance is 0.5～1Mpa; 450～460 ℃ of temperature of reaction; Reaction times 4～6h.
Compare with the normal pressure synthesis method, the present invention has distilling effect unlike normal pressure synthesis when synthetic, small molecules such as small molecules silicon-carbon alkane, hydrocarbon polymer, the hydrogen system of can not overflowing, high pressure has increased the small molecules concentration of reactants that has than high reaction activity on the one hand, participates in the dehydrogenative condensation reaction; On the other hand, micromolecular existence increases system pressure, has promoted the intermolecular reaction of other PCS, impels molecular weight to increase.Therefore, after underpressure distillation, high pressure synthetic PCS molecular weight is than PCS yield height, molecular weight height, the softening temperature height of normal pressure synthesis under the same conditions.
Therefore, the present invention has following advantage: (1) increases reaction pressure, improves reactant concn, improves speed of reaction, increases the molecular weight of precursor, improves synthetic yield; (2) simplified equipment, required equipment only are autoclave, if from the synthetic precursor of PDMS, the constant-pressure and high-temperature cracking process also needs the PDMS cracking apparatus except that the needs synthesis device; (3) technology controlling and process is simplified, and processing parameter only is temperature of reaction, reaction times, precharge pressure, and the reaction times shortens dramatically; (4) can accurately control the amount of introducing reactant, second component such as the BCl of particularly volatile or distillation
3, Al (AcAc)
3, Fe (CO)
5Deng, reaction process is simplified, especially be fit to the precursor that preparation contains different elements such as B, Al, Fe.
Description of drawings
The infrared spectrum of accompanying drawing 1:PDMS and PCS;
Accompanying drawing 1:PCS-HP's
1The H-NMR spectrogram.
Embodiment
The invention will be further described below in conjunction with embodiment.
(1) take PDMS as the embodiment of the synthetic PCS of raw material High Temperature High Pressure
250gPDMS is placed in the autoclave, vacuumize repeatedly and replace gas reactor, finally add the N of 0.5Mpa in advance with high pure nitrogen
2, sealing; Temperature programming to 450 ℃ then, reaction 6h promptly gets the thick product of PCS after the cooling.This thick product is through xylene soluble, filtration, and filtrate is carried out underpressure distillation at 350 ℃, gets pale brown chromoresin shape PCS precursor (PCS-HP) after the cooling.
With characteristics such as the composition structure of PCS-HP, Si-H linkage content, productive rate, molecular weight the present invention is made evaluation below, and make comparisons with the characteristic of the PCS-NP with close softening temperature of normal pressure synthesis.
1, elementary composition
Relatively have PCS-NP elementary composition of approximate softening temperature normal pressure synthesis, find that both constituent contents are suitable substantially, the empirical formula basically identical.Results of elemental analyses sees Table 1.
The results of elemental analyses of table 1 PCS
| Sample | Si/wt％ | C/wt％ | H/wt％ | O/wt％ | Empirical formula |
| PCS-HP | 48.33 | 38.65 | 12.31 | 0.71 | Si 1.87H 7.13O 0.03 |
| PCS-NP | 48.22 | 38.14 | 13.11 | 0.53 | Si 1.85H 7.61O 0.02 |
2, infrared analysis
The infrared spectrum of PDMS, the PCS-HP with close softening temperature and PCS-NP as shown in Figure 1.
As seen from Figure 1, the structural similitude of PCS-HP and PCS-NP, wherein 1250cm
-1The place is Si-CH
3The distortion peak, 2100cm
-1The place is Si-H stretching vibration peak, relatively 2100cm
-1And 1250cm
-1The charateristic avsorption band absorbancy at place, the Si-H content that gets PCS-HP is 0.99.Compare (A with PCS-NP
Si-H/ A
Si-CH3=0.87), it is higher that height is pressed into the Si-H content of PCS, and active site is more.
When PCS is used for melt-spinning and prepares the SiC fiber, in follow-up not thaw process, introduce less oxygen and can realize not melting.Therefore, can reduce the fiber oxygen level, reduce the defective that produces because of the Si-C-O STRUCTURE DECOMPOSITION, improve the mechanical property and the resistance to elevated temperatures of fiber.
3, nuclear magnetic resonance spectroscopy
PCS-HP's
1The H-NMR nmr spectrum as shown in Figure 2.
In Fig. 2, near the resonance peak of the hydrogen that produces for c h bond δ=0ppm, δ=4～5ppm place is the resonance peak of the hydrogen in the Si-H key.The resonance peak area of comparison C-H and Si-H gets C-H and Si-H ratio is about 8.84, and the C-H/Si-H value of PCS-NP is about 9.12, and the Si-H content of visible PCS-HP is higher, and the result is consistent with the infrared spectrum gained.
By above analysis explanation, PCS-HP and PCS-NP are elementary composition, molecular structure is similar, and the Si-H linkage content of PCS-HP is higher.
4, molecular weight and distribution thereof
With the synthetic PCS of 450 ℃ of 6h is example, and the PCS productive rate of normal pressure synthesis is about 35%, and 195～205 ℃ of softening temperatures, Si-H content be less than 0.9, and weight-average molecular weight is about 2500, does not have the high molecular part (on the graph of molecular weight distribution of PCS, to think logM
w＞4.0 is the high molecular part).And high pressure synthetic PCS productive rate is about 45%, and 200～210 ℃ of softening temperatures, Si-H linkage content are 0.96, and weight-average molecular weight is about 2750, and high molecular partly accounts for 8%, as seen all increases than the PCS specific performance index of normal pressure synthesis.
The high molecular part of high pressure synthetic PCS is higher, and is favourable to fibre strength.Therefore, by control certain reaction condition, adopt high-pressure process can synthesize the PCS that softening temperature is higher than 330 ℃, this PCS is more suitable for carrying out dry-spinning and prepares the SiC fiber.
(2) with lower molecular weight PCS be the embodiment of the synthetic PCS of raw material High Temperature High Pressure
PCS places in the autoclave with the 300g lower molecular weight, vacuumizes repeatedly and replaces gas reactor with high pure nitrogen, finally adds the N of 0.5Mpa in advance
2, sealing.Temperature programming to 430 then～490 ℃, reaction 0.5h promptly gets the thick product of PCS after the cooling.This thick product is through xylene soluble, filtration, and filtrate is carried out underpressure distillation at 350 ℃, gets arborescens PCS precursor after the cooling.The characteristic parameter of this PCS sees Table 2.
The characteristic parameter of the synthetic PCS of table 2 lower molecular weight PCS
| Sample | Softening temperature/℃ | The Si-H linkage content | Weight-average molecular weight | Dispersion coefficient | Polymer content/% |
| Raw material | 150 | 0.9194 | 2069 | 1.65 | 2 |
| 430 | 164 | 0.9221 | 2257 | 1.77 | 3 |
| 440 | 172 | 0.9094 | 2536 | 1.94 | 4.5 |
| 450 | 178 | 0.8916 | 2744 | 1.91 | 5 |
| 460 | 186 | 0.8842 | 2902 | 2.06 | 6 |
| 470 | 204 | 0.8910 | 3455 | 2.50 | 8 |
| 480 | 224 | 0.8788 | 4353 | 3.01 | 12 |
| 490 | 272 | 0.8485 | 7750 | 4.36 | 25 |
By table 2 as seen, along with the raising of temperature of reaction, the softening temperature of PCS improves gradually, and the Si-H linkage content reduces, and molecular weight increases gradually, and polymer content increases, and molecular weight distribution broadens.Change reaction conditions, and in addition appropriate postprocessing can obtain the PCS of desired characteristic.
(3) take LPS as the embodiment of the synthetic PCS of raw material High Temperature High Pressure
With 200gLPS (LPS by PDMS in nitrogen atmosphere more than 360 ℃ cracking and get) place in the autoclave, replace gas reactor with high pure nitrogen repeatedly, finally add the N of 0.5Mpa in advance
2, sealing.Temperature programming to 450 then～470 ℃, reaction 2～8h promptly gets the thick product of PCS after the cooling.This thick product is through xylene soluble, filtration, and filtrate is carried out underpressure distillation at 350 ℃, gets light yellow arborescens PCS precursor after the cooling.The characteristic parameter of this PCS sees Table 3.
Table 3 is the influences of the different synthesis conditions of raw material to the PCS characteristic with LPS
| Sample | PCS productive rate/% | Softening temperature/℃ | The Si-H linkage content | Weight-average molecular weight | Polymer content/% |
| 470-2 | 47.47 | 201 | 0.902 | 3497 | 7 |
| 470-4 | 52.89 | 283 | 0.8682 | 12795 | 32 |
| 470-6 | 12.42 | ＞325 | 0.8045 | 32959 | 28.5 |
| 470-8 | 10.15 | ＞340 | 0.8228 | 52849 | 37 |
| 460-2 | 46.74 | 172 | 0.9458 | 2221 | 2 |
| 460-4 | 47.42 | 226 | 0.9007 | 3709 | 9.5 |
| 460-6 | 46.62 | 283 | 0.9340 | 6269 | 19.5 |
| 460-8 | 57.84 | ＞330 | 0.8744 | 14298 | 32 |
| 450-2 | 38.31 | 159 | 0.9928 | 1274 | 0 |
| 450-4 | 43.28 | 181 | 0.9845 | 1638 | 0 |
| 450-6 | 43.99 | 201 | 0.9692 | 2090 | 1.5 |
| 450-8 | 47.54 | 246 | 0.9721 | 3246 | 6.5 |
By table 3 as seen, along with the raising of temperature of reaction, the prolongation in reaction times, the softening temperature of PCS improves gradually, and the Si-H linkage content reduces, and molecular weight increases gradually, and polymer content increases, and molecular weight distribution broadens.Change temperature of reaction and time and in addition appropriate postprocessing can obtain the PCS of desired characteristic.
(4) High Temperature High Pressure that contains aluminium PCS is synthesized embodiment
Al (AcAc) with 200gLPS and 3～6wt%
3Place in the autoclave, vacuumize repeatedly and replace gas reactor, finally add the N of 0.5Mpa in advance with high pure nitrogen
2, sealing.Temperature programming to 450 ℃ then, reaction 6h promptly gets the thick product of PCS after the cooling.This thick product is through xylene soluble, filtration, and filtrate is carried out underpressure distillation at 350 ℃, gets orange arborescens PCS precursor after the cooling.The characteristic parameter of this PCS sees Table 4.
Table 4 contains the characteristic parameter of aluminium PCS
| Sample | Al(AcAc) 3/wt％ | Productive rate/% | Softening temperature/℃ | The Si-H linkage content | Weight-average molecular weight |
| PCS-1 | 3 | 44.2 | 235～245 | 0.76 | 5074 |
| PCS-2 | 6 | 26.6 | 290～300 | 0.70 | 9109 |
By table 4 as seen, add aluminium acetylacetonate (Al (AcAc) among the LPS
3), under High Temperature High Pressure, can synthesize PCS, and synthetic PCS is with Al (AcAc)
3The difference of content and have characteristic parameters such as different molecular weight and softening temperature.
(5) the synthetic embodiment of the High Temperature High Pressure of rich carbon PCS
The PVC of 200gLPS and 1～7wt% is placed in the autoclave, vacuumize repeatedly and replace gas reactor, finally add the N of 0.5Mpa in advance with high pure nitrogen
2, sealing.Temperature programming to 450 ℃ then, reaction 6h promptly gets the thick product of PCS after the cooling.This thick product is through xylene soluble, filtration, and filtrate is carried out underpressure distillation at 350 ℃, gets the PCS precursor of the rich carbon of pale brown chromoresin shape after the cooling.The characteristic parameter of this PCS sees Table 5.
By table 5 as seen, add polyvinyl chloride (PVC) among the LPS, under High Temperature High Pressure, can synthesize PCS, and along with the change that adds the PVC amount, synthetic PCS has different molecular weight and softening temperature.
The characteristic parameter of the rich carbon PCS of table 4
| Sample | PVC/wt％ | Productive rate/% | Softening temperature/℃ | The Si-H linkage content | Weight-average molecular weight |
| PCS-1 | 1 | 51.53 | 168～178 | 0.84 | 2040 |
| PCS-2 | 5 | 43.62 | 177～187 | 0.81 | 2107 |
| PCS-3 | 7 | 40.33 | 190～200 | 0.78 | 2380 |
In sum, the PCS precursor can be synthesized,, the PCS precursor of different softening point, molecular weight and Si-H key can be obtained by control certain reaction condition with the different material High Temperature High Pressure.
Claims (3)
1, a kind of synthetic method of polycarbosilane precusor, it is characterized in that, may further comprise the steps: (1) places polydimethyl silane or liquid polysilane or weight-average molecular weight in the autoclave less than 2000 small molecules Polycarbosilane, vacuumize repeatedly and replace gas reactor, finally add the N of 0.1-5MPa in advance with high pure nitrogen
2, sealing; (2) temperature programming is to 430-490 ℃, and reaction 0.5-10h promptly gets the thick product of Polycarbosilane after the cooling; (3) should thick product through xylene soluble, filtration, filtrate is carried out underpressure distillation at 330-380 ℃, promptly gets the arborescens polycarbosilane precusor after the cooling.
2, the synthetic method of polycarbosilane precusor according to claim 1, it is characterized in that, in raw materials used, also be added with and be equivalent to polydimethyl silane or liquid polysilane or weight-average molecular weight the compound that contains B, Al, Fe less than 2000 small molecules Polycarbosilane weight 2-10wt%.
3, the synthetic method of polycarbosilane precusor according to claim 1, it is characterized in that, in raw materials used, also be added with and be equivalent to polydimethyl silane or liquid polysilane or weight-average molecular weight polyvinyl chloride less than 2000 small molecules Polycarbosilane weight 1-10wt%.
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Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101240070B (en) * | 2007-02-09 | 2012-05-30 | 中国人民解放军国防科学技术大学 | Supercritical fluid synthesis method of ceramic precursor polycarbosilane |
| CN102030904B (en) * | 2010-12-08 | 2012-05-23 | 中国人民解放军国防科学技术大学 | Method for preparing spinnable polysiloxane ceramic precursor for SiC fibers |
| CN102120822B (en) * | 2011-04-02 | 2012-05-02 | 中国人民解放军国防科学技术大学 | Method for synthesizing polycarbosilane at normal pressure |
| CN102585235B (en) * | 2012-01-17 | 2013-08-28 | 中国人民解放军国防科学技术大学 | Catalytic synthesis method of polycarbosilane precursor |
| CN103772710B (en) * | 2014-02-26 | 2016-02-17 | 中国人民解放军国防科学技术大学 | A kind of synthetic method of high softening-point spinning-grade Polycarbosilane |
| CN105384940B (en) * | 2015-12-10 | 2018-02-23 | 中国人民解放军国防科学技术大学 | A kind of synthetic method of spinning-grade polyaluminocarbosilane precursor |
| CN105566637B (en) * | 2016-03-14 | 2018-04-17 | 黑龙江省科学院石油化学研究院 | A kind of synthetic method of Polycarbosilane |
| CN110078926A (en) * | 2019-05-16 | 2019-08-02 | 湖南远辉新材料研究院有限公司 | A kind of high-volume high pressure synthesis method of Polycarbosilane |
| CN111019141B (en) * | 2019-12-10 | 2021-12-31 | 江苏赛菲新材料有限公司 | Method for synthesizing polycarbosilane |
| CN111019142A (en) * | 2019-12-10 | 2020-04-17 | 江苏赛菲新材料有限公司 | Improved synthesis method of polycarbosilane |
| CN112048068A (en) * | 2020-08-05 | 2020-12-08 | 福建立亚化学有限公司 | Method for preparing solid polycarbosilane by recovering polydimethylsiloxane cracking residues |
| CN112062967B (en) * | 2020-08-05 | 2022-08-30 | 福建立亚化学有限公司 | Preparation method of polycarbosilane ceramic precursor material |
| CN113667129B (en) * | 2021-09-22 | 2022-09-02 | 湖南希里肯科技有限公司 | Spinning-grade polycarbosilane and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4377677A (en) * | 1980-11-11 | 1983-03-22 | Ube Industries, Ltd. | Method of preparing polycarbosilanes |
| JPS59138230A (en) * | 1983-01-27 | 1984-08-08 | Ryuzo Kasahara | Production of polycarbosilane |
| CN1010601B (en) * | 1987-02-10 | 1990-11-28 | 国营机械和化学清洗锅炉联合工厂 | Hydraulic pulse generator |
| JPH0586200A (en) * | 1991-06-20 | 1993-04-06 | Tonen Corp | Thermosetting copolymer and its production |
| US5292830A (en) * | 1991-06-20 | 1994-03-08 | Tonen Corporation | Thermosetting copolymers, silicon carbide-based fiber and processes for producing same |
-
2004
- 2004-05-12 CN CNB2004100231854A patent/CN1298767C/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4377677A (en) * | 1980-11-11 | 1983-03-22 | Ube Industries, Ltd. | Method of preparing polycarbosilanes |
| JPS59138230A (en) * | 1983-01-27 | 1984-08-08 | Ryuzo Kasahara | Production of polycarbosilane |
| CN1010601B (en) * | 1987-02-10 | 1990-11-28 | 国营机械和化学清洗锅炉联合工厂 | Hydraulic pulse generator |
| JPH0586200A (en) * | 1991-06-20 | 1993-04-06 | Tonen Corp | Thermosetting copolymer and its production |
| US5292830A (en) * | 1991-06-20 | 1994-03-08 | Tonen Corporation | Thermosetting copolymers, silicon carbide-based fiber and processes for producing same |
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