CN101367944B - Preparation method for boron nitride ceramics fibre precursor - Google Patents
Preparation method for boron nitride ceramics fibre precursor Download PDFInfo
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- CN101367944B CN101367944B CN200810200531XA CN200810200531A CN101367944B CN 101367944 B CN101367944 B CN 101367944B CN 200810200531X A CN200810200531X A CN 200810200531XA CN 200810200531 A CN200810200531 A CN 200810200531A CN 101367944 B CN101367944 B CN 101367944B
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Abstract
The invention relates to a method for preparing boron nitride ceramic fiber precursor polymer, the method comprises the following steps: the anhydrous toluene solution of cyclic trichloroboron azane is cooled to 80 DEG C below zero-70 DEG C below zero, anhydrous toluene solution of methylamine is dripped, and the reaction endures 1-10 hours under -40 DEG C below zero -0 DEG C, and then endures 10-20 hours under room temperature, and is subsequently filtered; the boron trichloride is condensed in anhydrous toluene solution of methylamine (40 DEG C below zero - 80 DEG C below zero), stirred for reaction for 1-10hr, and then stirred for 5-20hr under room temperature, and then filtered; the filtrates are combined, stirred for 2-4hr under 10 DEG C below zero -0 DEG C, stirred for 5-10hr under room temperature, and then filtered; the filtrates react for 10-60min under 50-100 DEG C, the toluene is evaporated out under 100-120 DEG C, and then react for 5-20hr under 160-170 DEG C. The precursor polymer synthesized by the method has a proper linear shape and a mesh structure, and has sound spinnability and wave-penetrating performance.
Description
Technical field
The present invention relates to a kind of preparation method of boron nitride ceramics fibre precursor, belong to technical field of polymer materials.
Background technology
Along with the particularly develop rapidly of space flight and aviation industry of Modern High-Tech, the research and development high-performance fiber is the high-performance inorganic ceramic fiber especially, has become one of emphasis of current Materials science research in the world.Boron nitride fibre is compared with some inorganic fibre, have that high strength at high temperature, oxidation-resistance, resistance to chemical attack, density are little, workability, self-lubricating, do not soak into multiple metal, high dielectric property, good thermal conductivity and good good characteristics such as wave penetrate capability.Its oxidation resistance temperature is than the height of carbon fiber, boron fibre.Under inert conditions, still keep stable more than 2500 ℃, in oxidizing atmosphere, 850 ℃ are still stable, therefore, it can be used as solar heat protection, lagging material, high-temperature-resistant filtering material and electrical apparatus insulation material, particularly the potential application foreground of this fiber aspect the aerospace flight technology field is more wide, can make anti-ablation cover, Electric insulator, radar scanner window, military protection suit, anti-NEUTRON PROTECTION cover and the parachute of reentrying etc.; It has that the electromagnetic radiation resistant of wide region, density are little, high-temperature oxidation resistance, high heat of gasification and excellent lubrication characteristic, compare with graphite, the BN thermal expansivity is little, and can make oxide ceramics have good unreactiveness, can be used as the ideal boundary material: and the BN fiber has high Young's modulus and has high intensity simultaneously, makes it can be used as a kind of high performance strongthener again.Thereby enjoy the concern of Chinese scholars, become the focus of ceramic fiber research in recent years.
The preparation method of BN ceramic fiber has two kinds usually, and a kind of is traditional inorganic precursor high-temperature powder sintering process, and another kind is an organic precursor method method pyrolysis method.Because inorganic method has demonstrated many shortcomings that are difficult to overcome on preparation BN fiber, from the end of the eighties abroad to utilizing organic boron-nitrogen polymer to make the BN fiber through spinning, non-melt processed, high-temperature heat treatment for precursor, carried out comparatively extensive studies.The earliest with the organic precursor body method prepare the BN fiber be Japanese scholar Tan iguchi report in 1976 utilize the amino borazole of N-phenyl-B-as precursor pyrolysis prepare tensile strength BN fiber preferably, but regrettably because of the existing problems that remove of carbon, the result of this report can not repeat.In grant number is 4,581,468, authorizing day is April8, having introduced the method that a kind of organo-boron polymer prepares boron nitride fibre in 1986 the United States Patent (USP) " Boron nitride preceramic polymers ", is to react acquisition by ammonia (ammonolysis) and three chloro-trialkyl silicomethane-borazoles (ring compound), because initial compounds is difficult to preparation, cause this method to involve great expense, be difficult to carry out.There were many methods to prepare boron-nitrogen compound afterwards again, for example R T PAINE etc. is at " SyntheticRoutes to Boron Nitride " (Chemical Reviews, 1990, Vol.90, No.1,73~91) elaboration is synthesized preceramic polymer with organic compound such as boron azane, C K Narula etc. are at " Models andPolyborazine Precursors for Boron Nitride Ceramics " (Chem Mater.1990.2,384~389) use trichlorine boron azane or 2-dimethylin-4 in, 6-dichloro boron azane is with the hexa methyl silazane synthetic precursor of reaction in the dichloromethane solution at room temperature, and publication number is by functional group [B (NR in the French Patent " Processfor the production of polyaminoborazines " of FR2695645
1R
2)-NR
3-]
3Thermal polycondensation and obtain precursor, R wherein
1, R
2And R
3The expression or identical or different hydrogen bases or alkyl.Top these polymkeric substance of telling about are suitable for preparing the coating of powder or some forms, but with these polymer manufacture more the complexity film particularly fiber be very difficult.
After more than 10 year, Wade has prepared solvable fusile BN precursor, but claims that this precursor melt-spun is a fiber.Nearly 10 in the past few years, the foreign scholar has explored the approach of various preparation BN precursor, and B.Bonnetot. had reported the novel process for preparing the BN fiber with boron trichloride and the synthetic precursor of methylamine in 1994, but this method synthetic precursor is a network-like structure, viscosity is bigger, is unfavorable for the spinning technique in later stage.
Summary of the invention
The preparation method who the purpose of this invention is to provide a kind of boron nitride ceramics fibre precursor, it can access the existing line structure cancellated, as to have better spinning property poly-boron azane precursor again.
In order to achieve the above object, technical scheme of the present invention provides a kind of preparation method of boron nitride ceramics fibre precursor, it is characterized in that, concrete steps are:
The first step, the anhydrous toluene solution of 40-45wt% ring-type trichlorine boron azane is cooled to-80 ℃~-70 ℃ with refrigeration equipment, under the magnetic agitation condition, drip the anhydrous toluene solution of 40-45wt% methylamine, after dripping end, be warming up to-40 ℃~0 ℃, stirring reaction 1~10 hour, be warming up to room temperature again, reacted 10~20 hours, and filtered and remove precipitation, and precipitate 1~8 time with the dry toluene flushing, merging filtrate, be warmed up to 30-60 ℃ then under the vacuum of 3-5 mmhg and remove part toluene, wherein, the weight ratio of methylamine and ring-type trichlorine boron azane is 3:10~2:5;
Second step, with tetrafluoroethylene pipe and refrigeration equipment boron trichloride is condensed in-40 ℃~-80 ℃ the anhydrous toluene solution of 40-45wt% methylamine, magnetic agitation reaction 1~10hr, be warming up to room temperature again, stir 5~20hr, filter the removal precipitation and obtain filtrate, wherein the weight ratio of boron trichloride and methylamine is 2:5~9:20, and the weight ratio of the ring-type trichlorine boron azane that adds in the boron trichloride and the first step is 7:10~3:4;
In the 3rd step, the first step and second is gone on foot the filtrate that obtains mix, at-10 ℃~0 ℃ magnetic agitation 2-4hr, be warming up to stirring at room 5-10hr again, filter out precipitation, filtrate under agitation condition, is warming up to 50 ℃~100 ℃, insulation 10~60min, be warming up to 100 ℃~120 ℃ again,, be warming up to 160-170 ℃ again up to having steamed toluene solvant, insulation 5~20hr is cooled to room temperature.
Used refrigeration equipment was preferably PSL-1800 type magnetic agitation cryostat, during the first step and second went on foot.
Used dry toluene was preferably the dry toluene through drying treatment during the first step and second went on foot.
The first step, second step and the 3rd step preferably carry out under the condition of nitrogen or argon shield.
Filtrate heat-up rate in the 3rd step is preferably 0.5~20 ℃/min.
Reaction process of the present invention is as follows:
Owing to contain 2 strong polarity B-C1 keys in the small molecule monomer 1, be the Lewis acid of the last one, so can be that the small molecule monomer 2 of Lewis alkali reacts, obtain having certain linear and cancellated boron nitride precursor body polymkeric substance with performance.
The present invention has the following advantages:
1. the boron nitride ceramics fibre precursor for preparing has certain linear and reticulated structure, has better spinnability, helps the preparation of boron nitride fibre;
2. the ceramic fiber precursor that makes in the ammonia atmosphere, be heated to 900 ℃ of resulting products through ultimate analysis as can be known the content of carbon be less than 0.003, can reach good wave;
3. the by product that forms in the reaction process-alkyl ammomium chloride solid is to form in the synthesized micromolecule monomer stage, separates from reaction system easily.
Description of drawings
Fig. 1 is the infrared spectrum of small molecule monomer 1;
Fig. 2 is the nucleus magnetic resonance boron spectrogram of small molecule monomer 1;
Fig. 3 is the boron nitride ceramics fibre precursor infrared spectrum;
Fig. 4 is a boron nitride ceramics fibre precursor nucleus magnetic resonance boron spectrogram.
Embodiment
Specify the present invention below in conjunction with embodiment.
A kind of preparation method of boron nitride ceramics fibre precursor, concrete steps are:
The first step: the anhydrous toluene solution of 40wt% ring-type trichlorine boron azane (36.3g) is cooled to-80 ℃ with PSL-1800 type magnetic agitation cryostat,, under the magnetic agitation condition, drip the anhydrous toluene solution of 40wt% methylamine, cotton-shaped methyl ammonia chloride precipitation with regard to adularescent generates immediately, after dripping end, be warming up to-40 ℃, reacted 1 hour, be warming up to room temperature again, reacted 10 hours, and filtered and remove precipitation, and precipitate 1 time with the dry toluene flushing, merging filtrate, be warmed up to 60 ℃ and remove part toluene under the vacuum tightness of 3 mmhg, wherein, the weight ratio of methylamine and ring-type trichlorine boron azane is 3:10;
Second step: with PSL-1800 type magnetic agitation cryostat, and tetrafluoroethylene pipe boron trichloride is condensed in-40 ℃ the anhydrous toluene solution of 40wt% methylamine, magnetic agitation reaction 1hr, be warming up to room temperature again, stir 5hr, there is the yellow solid precipitation to generate, filter the removal precipitation and obtain filtrate, wherein the weight ratio of boron trichloride and methylamine is 2:5, and the weight ratio of the ring-type trichlorine boron azane that adds in the boron trichloride and the first step is 7:10;
The 3rd step: the first step and second is gone on foot the filtrate that obtains mix,, be warming up to stirring at room 5hr again at-10 ℃ of magnetic agitation 2hr, filter out precipitation, with filtrate under agitation condition, oil bath heat temperature raising to 50 ℃, insulation 10min, be warming up to 100 ℃ again, up to having steamed toluene solvant, be warming up to 160 ℃ again, insulation 5hr, being cooled to room temperature and getting yellow crystalline solid, promptly is the BN precursor.
Wherein, the first step and in second step used dry toluene be dry toluene through drying treatment.Before reaction process in the first step, second step, the 3rd step begins, go out air in the reactive system, the first step and filter in second step that to remove precipitation be to carry out in being full of the glove box of nitrogen with nitrogen replacement.Filtrate heat-up rate in described the 3rd step is 0.5 ℃/min.
Embodiment 2
A kind of preparation method of boron nitride ceramics fibre precursor, concrete steps are:
The first step: the anhydrous toluene solution of 45wt% ring-type trichlorine boron azane (36.3g) is cooled to-70 ℃ with refrigeration equipment, under the magnetic agitation condition, drip the anhydrous toluene solution of 45wt% methylamine, cotton-shaped methyl ammonia chloride precipitation with regard to adularescent generates immediately, after dripping end, be warming up to 0 ℃, reacted 10 hours, be warming up to room temperature again, reacted 20 hours, and filtered and remove precipitation, and precipitate 8 times with the dry toluene flushing, merging filtrate, remove part toluene under 30 ℃ being warmed up under the vacuum tightness of 5 mmhg, wherein, the weight ratio of methylamine and ring-type trichlorine boron azane is 2:5;
Second step: with refrigeration equipment and tetrafluoroethylene pipe boron trichloride is condensed in-80 ℃ the anhydrous toluene solution of 45wt% methylamine, magnetic agitation reaction 10hr, be warming up to room temperature again, stir 20hr, there is the yellow solid precipitation to generate, filter the removal precipitation and obtain filtrate, wherein the weight ratio of boron trichloride and methylamine is 9:20, and the weight ratio of the ring-type trichlorine boron azane that adds in the boron trichloride and the first step is 3:4;
The 3rd step: the first step and second is gone on foot the filtrate that obtains mix,, be warming up to stirring at room 10hr again at 0 ℃ of magnetic agitation 4hr, filter out precipitation, filtrate under agitation condition, is warming up to 100 ℃, insulation 60min, be warming up to 120 ℃ again, up to having steamed toluene solvant, be warming up to 170 ℃ again, insulation 20hr, being cooled to room temperature and getting yellow crystalline solid, promptly is the BN precursor.
Wherein, used refrigeration equipment was a PSL-1800 type magnetic agitation cryostat, during the first step and second went on foot.Dry toluene used during the first step and second goes on foot is the dry toluene through drying treatment.Before the reaction process in the first step, second step and the 3rd step begins, go out air in the reaction system, the first step and filter in second step that to remove precipitation be to carry out in being full of the glove box of argon gas with argon replaces.Filtrate heat-up rate in described the 3rd step is 20 ℃/min.
Embodiment 3
A kind of preparation method of boron nitride ceramics fibre precursor, concrete steps are:
The first step, the synthesized micromolecule monomer 1 by the following method: the anhydrous toluene solution of 43wt% ring-type trichlorine boron azane (36.3g) is cooled to-75 ℃ with refrigeration equipment, under the magnetic agitation condition, drip the anhydrous toluene solution of 43wt% methylamine, cotton-shaped methyl ammonia chloride precipitation with regard to adularescent generates immediately, after dripping end, be warming up to-20 ℃, reacted 5 hours, and be warming up to room temperature again, reacted 15 hours, filter and remove precipitation, and with dry toluene flushing precipitation 4 times, merging filtrate is warmed up to 40 ℃ and removes part toluene under the vacuum tightness of 4 mmhg, wherein, the weight ratio of methylamine and ring-type trichlorine boron azane is 7:20.As shown in Figure 1, the infrared spectrum of the small molecule monomer 1 that obtains for the first step; Fig. 2 is the nucleus magnetic resonance boron spectrogram of small molecule monomer 1.
Second step, the synthesized micromolecule monomer 2 by the following method: with refrigeration equipment and tetrafluoroethylene pipe boron trichloride is condensed in-60 ℃ the anhydrous toluene solution of 43wt% methylamine, magnetic agitation reaction 5hr, be warming up to room temperature again, stir 15hr, have the yellow solid precipitation to generate, filter the removal precipitation and obtain filtrate, wherein the weight ratio of boron trichloride and methylamine is 17:40, and the weight ratio of the ring-type trichlorine boron azane that adds in the boron trichloride and the first step is 29:40.
In the 3rd step, the first step and second is gone on foot the filtrate that obtains mix, at-5 ℃ of magnetic agitation 3hr, be warming up to stirring at room 8hr again, filter out precipitation, with filtrate under agitation condition, be warming up to 75 ℃, insulation 30min is warming up to 110 ℃ again, up to having steamed toluene solvant, be warming up to 165 ℃ again, insulation 15hr, being cooled to room temperature, being cooled to room temperature and getting yellow crystalline solid, promptly is the BN precursor, Fig. 3 is its infrared spectrum, and Fig. 4 is a nucleus magnetic resonance boron spectrogram.
Wherein, used refrigeration equipment was a PSL-1800 type magnetic agitation cryostat, during the first step and second went on foot.Dry toluene used during the first step and second goes on foot is the dry toluene through drying treatment.Before the reaction process in the first step, second step and the 3rd step begins, fall air in the reaction system, the first step and filter in second step that to remove precipitation be to carry out in being full of the glove box of nitrogen with nitrogen replacement.Filtrate heat-up rate in described the 3rd step is 10 ℃/min.
Boron nitride ceramics fibre precursor constituent content after the cracking in the ammonia atmosphere sees the following form among the embodiment 1-3, and by table as can be seen, the content of carbon has been less than 0.3wt% after the sample ammonification, can guarantee that like this its precursor has good wave.In addition, can infer the structural unit formula of the boron nitride ceramics fibre precursor after the cracking, infer that with reaction mechanism the existing present situation that has cancellated conclusion to match again according to each constituent content in the table.
Claims (5)
1. the preparation method of a boron nitride ceramics fibre precursor is characterized in that, concrete steps are:
The first step, the anhydrous toluene solution of 40-45wt% ring-type trichlorine boron azane is cooled to-80 ℃~-70 ℃ with refrigeration equipment, under the magnetic agitation condition, drip the anhydrous toluene solution of 40-45wt% methylamine, after dripping end, be warming up to-40 ℃~0 ℃, stirring reaction 1~10 hour, be warming up to room temperature again, reacted 10~20 hours, and filtered and remove precipitation, and precipitate 1~8 time with the dry toluene flushing, merging filtrate, be warmed up to 30-60 ℃ then under the vacuum of 3-5 mmhg and remove part toluene, wherein, the weight ratio of methylamine and ring-type trichlorine boron azane is 3: 10~2: 5;
Second step, with tetrafluoroethylene pipe and refrigeration equipment boron trichloride is condensed in-40 ℃~-80 ℃ the anhydrous toluene solution of 40-45wt% methylamine, magnetic agitation reaction 1~10 hour, be warming up to room temperature again, stirred 5~20 hours, filter the removal precipitation and obtain filtrate, wherein the weight ratio of boron trichloride and methylamine is 2: 5~9: 20, and the weight ratio of the ring-type trichlorine boron azane that adds in the boron trichloride and the first step is 7: 10~3: 4;
The 3rd step, the first step and second filtrate that obtains of step are mixed ,-10 ℃~0 ℃ magnetic agitation 2-4 hour, be warming up to again stirring at room 5-10 hour, filter out precipitation, filtrate under agitation condition, is warming up to 50 ℃~100 ℃, insulation 10~60min, be warming up to 100 ℃~120 ℃ again,, be warming up to 160-170 ℃ again up to having steamed toluene solvant, be incubated 5~20 hours, be cooled to room temperature.
2. the preparation method of a kind of boron nitride ceramics fibre precursor as claimed in claim 1 is characterized in that, used refrigeration equipment was a PSL-1800 type magnetic agitation cryostat, during the first step and second went on foot.
3. the preparation method of a kind of boron nitride ceramics fibre precursor as claimed in claim 1 is characterized in that, dry toluene used during the first step and second goes on foot is the dry toluene through drying treatment.
4. the preparation method of a kind of boron nitride ceramics fibre precursor as claimed in claim 1 is characterized in that, the described the first step, second step and the 3rd step are what to be carried out under the condition of nitrogen or argon shield.
5. the preparation method of a kind of boron nitride ceramics fibre precursor as claimed in claim 1 is characterized in that, the each heat-up rate that heats up of filtrate in described the 3rd step is all 0.5~20 ℃/min.
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CN112316567B (en) * | 2020-10-19 | 2022-07-22 | 江苏大学 | Nanofiber filter membrane and preparation method and device thereof |
CN114715861B (en) * | 2022-03-24 | 2023-07-28 | 中国人民解放军国防科技大学 | Synthesis method of linear macromolecule BN precursor |
CN114891229B (en) * | 2022-03-24 | 2023-11-14 | 中国人民解放军国防科技大学 | Synthesis method of spinnable BN precursor with high ceramic yield |
CN115806435B (en) * | 2023-02-09 | 2023-06-16 | 山东工业陶瓷研究设计院有限公司 | Preparation method of boron nitride powder |
CN117210043B (en) * | 2023-10-19 | 2024-07-16 | 青岛恩泽化工有限公司 | Water-based flash rust prevention agent and preparation method thereof |
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EP1329437A3 (en) * | 2002-01-22 | 2005-09-28 | EADS SPACE Transportation SA | Method of production of boron nitride fibers and the obtained fibers |
EP1329436A3 (en) * | 2002-01-22 | 2005-09-28 | EADS SPACE Transportation SA | Method of production of boron nitride fibers starting from borylborazines |
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