SiBCN precursor for prepreg, prepreg, composite material and preparation method of SiBCN precursor

Abstract

The invention provides a SiBCN precursor for a prepreg, the prepreg, a composite material and a preparation method of the SiBCN precursor for the prepreg, and the preparation method comprises the following steps: taking dichloromethylvinylsilane, boron trichloride and disilazane as raw materials, and preparing the SiBCN precursor for the prepreg through a one-step method; the homogeneous impregnation slurry is prepared by blending the SiBCN precursor and the ceramic powder at a high temperature, so that the components of the prepreg can be efficiently regulated and controlled, and the prepreg prepared by taking the impregnation slurry as an impregnation matrix can be used for preparing a special silicon resin-based composite material and a special ceramic-based composite material. A resin-based composite material and a ceramic-based composite material which are prepared by taking the prepreg prepared by the method as a raw material have excellent ablation performance and can be used for preparing a novel ablation composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of special precursors and prepregs, and particularly relates to a SiBCN precursor for prepregs, a prepreg, a composite material and a preparation method thereof. Background Art

[0002] Ceramic precursors are important raw materials for preparing ceramic matrix composites by the PIP method. Carbon fiber reinforced ceramic matrix composites prepared with ceramic precursors as raw materials have important applications in aerospace and other fields. However, most of the existing ceramic matrix composites are prepared by the precursor impregnation and curing pyrolysis process (PIP), which has the problems of expensive raw materials, many preparation steps, long manufacturing cycle, large damage to fiber weaving and multiple rounds of composite, low composite efficiency, high manufacturing cost, etc., which are difficult to meet the low-cost and short-cycle development requirements of ceramic matrix composites in the aerospace field, and have become a bottleneck restricting the widespread application of ceramic matrix composites. At the same time, the commonly used ceramic matrix composites are mainly Si-based composites, and their operating temperature usually does not exceed 1600℃, which is difficult to meet the higher operating temperature requirements. Summary of the invention

[0003] In order to overcome the deficiencies in the prior art, the inventors have conducted intensive research and provided a SiBCN precursor for prepreg, a prepreg, a composite material and a preparation method thereof, which solve the problems of insufficient temperature resistance of the composite material and the expensive raw materials, multiple preparation steps, long manufacturing cycle and high preparation cost of the precursor impregnation curing and cracking process.

[0004] Based on this, the present invention proposes a SiBCN precursor for prepreg, a prepreg, a composite material and a preparation method thereof, and the rheological properties of the prepared precursor meet the prepreg process requirements. At the same time, the introduction of carbides, borides, and nitrides containing ultra-high temperature metal components into the precursor as inorganic fillers to prepare the impregnation slurry for the prepreg can achieve the effective introduction of the metal component. At the same time, the introduction of the metal component effectively improves the ceramic yield of the mixed slurry and shortens the composite material preparation cycle. The prepreg prepared with the impregnation slurry as the raw material can not only be used to prepare ceramic-based composite materials, but also can be used to prepare resin-based composite materials, and has great application prospects in the field of high-temperature ablation materials.

[0005] The technical solution provided by the present invention is as follows:

[0006] In a first aspect, a method for preparing a SiBCN precursor for prepreg is characterized by comprising the following steps: using methylvinyldichlorosilane, boron trichloride and disilazane as raw materials, reacting at a temperature of 220 to 280° C. to obtain a SiBCN precursor;

[0007] Dichlorosilane has the following structure:

[0008]

[0009] Wherein, R1 and R2 are the same or different, and at least one of R1 and R2 contains an olefin group, and R1 and R2 are independently selected from the following groups: H, C 2-4 Olefin group.

[0010] In a second aspect, a SiBCN precursor for prepreg is prepared by the method for preparing a SiBCN precursor for prepreg according to the first aspect; preferably, the room temperature viscosity of the precursor is 20,000 to 500,000 cp, and the number average molecular weight of the precursor is 4,000 to 20,000.

[0011] In the third aspect, an impregnation slurry for prepreg comprises the SiBCN precursor and ceramic powder described in the second aspect, the mass fraction of the SiBCN precursor is 60% to 90%, and the mass fraction of the ceramic powder is 10% to 40wt%; preferably, the ceramic powder is one or more of hafnium carbide, zirconium carbide, tantalum carbide, silicon carbide, hafnium boride, zirconium boride, tantalum boride, hafnium nitride, zirconium nitride, tantalum nitride, etc.

[0012] In a fourth aspect, a prepreg is provided. The prepreg comprises a substrate and an impregnation slurry. The impregnation slurry is the impregnation slurry for prepreg according to the third aspect. Preferably, the volume fraction of the impregnation slurry in the prepreg is 40% to 70%.

[0013] In a fifth aspect, a method for preparing the prepreg according to the fourth aspect comprises:

[0014] The SiBCN precursor and the ceramic powder are heated and mixed to obtain an impregnation slurry;

[0015] The substrate is placed on a constant tension unwinding device and is pulled into a preheated dipping tank filled with impregnation slurry by the equipment. The substrate obtains a predetermined slurry content through a dipping amount control device. The prepared prepreg is then rolled up and refrigerated after being attached with a protective film.

[0016] In a sixth aspect, a fiber-reinforced resin-based composite material comprises: using the prepreg described in the fourth aspect to prepare a blank of a desired shape by winding or stacking, and preparing the fiber-reinforced resin-based composite material through vacuum-assisted curing and shaping.

[0017] In the seventh aspect, a fiber-reinforced ceramic-based composite material comprises: using the prepreg described in the fourth aspect to prepare a blank of a desired shape by winding or stacking, and preparing a fiber-reinforced resin-based composite material through vacuum-assisted curing and shaping; subjecting the fiber-reinforced resin-based composite material to a cracking reaction, and continuing to perform multiple rounds of precursor impregnation, curing, and cracking cycles to obtain a densified ceramic-based composite material.

[0018] The SiBCN precursor for prepreg, prepreg, composite material and preparation method thereof provided by the present invention have the following beneficial effects:

[0019] (1) The present invention introduces carbides, borides, and nitrides containing ultra-high temperature metal components into the precursor as inorganic fillers to prepare the impregnation slurry for prepreg, which can effectively introduce the metal components. At the same time, the introduction of the metal components effectively improves the ceramic yield of the mixed slurry and shortens the preparation cycle of the composite material.

[0020] (2) The present invention adopts a prepreg containing a SiBCN precursor and a ceramic powder, and prepares a blank of a desired shape by winding, stacking and laying, and then prepares a special silicone resin-based composite material through vacuum-assisted curing and shaping; the special silicone resin-based composite material can be densified by further high-temperature pyrolysis and combined with multiple rounds of impregnation slurry impregnation, curing, and cracking cycles to prepare a ceramic-based composite material; due to the introduction of ceramic components, the number of cycles is greatly reduced when preparing the ceramic-based composite material, and the traditional 8-15 cycles are reduced to 3-5 cycles. DETAILED DESCRIPTION

[0021] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0022] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0023] The invention provides a method for preparing a SiBCN precursor for prepreg, comprising the following steps: using methylvinyldichlorosilane, boron trichloride and disilazane as raw materials, reacting at a temperature of 220-280°C to obtain the SiBCN precursor.

[0024] Specifically: under the protection of an inert atmosphere, a solvent such as n-hexane and reaction raw materials such as methylvinyldichlorosilane, boron trichloride and disilazane are added to the reactor, stirred evenly and then heated for reaction, and heat-treated at 55-65, 75-85, 110-130, 150-170°C for 0.5-1h, and then heated to 220-280°C for 0.1-10h to obtain a room temperature viscous or solid SiBCN resin. The purpose of staged heating is to allow the resin to fully react in each reaction stage, while providing sufficient time for the reaction system to remove by-products and promote the forward progress of the reaction system.

[0025] In a preferred embodiment, in order to prepare SiBCN resin with suitable viscosity, the molar ratio of methylvinyldichlorosilane, boron trichloride and disilazane is 1:0.5-2:4-10.

[0026] In a preferred embodiment, dichlorosilane has the following structure:

[0027]

[0028] Wherein, R1 and R2 are the same or different, and at least one of R1 and R2 contains an olefin group, and R1 and R2 are independently selected from the following groups: H, C 2-4 Olefin (C 2-4 The alkene group refers to a straight-chain or branched alkene group containing one or two double bonds and having 2 to 4 carbon atoms).

[0029] The present invention also provides a SiBCN precursor for prepreg, which is prepared by the above-mentioned method for preparing the SiBCN precursor for prepreg, the room temperature viscosity of the precursor is 20,000 to 500,000 cp, the number average molecular weight of the precursor is 4,000 to 20,000, and it is converted into a fusible and soluble liquid under heating. The number average molecular weight and room temperature viscosity of the SiBCN precursor can be controlled by controlling the reaction temperature and time, and the above-mentioned number average molecular weight and room temperature viscosity precursor can be obtained, which can ensure that the impregnation slurry prepared after adding ceramic powder has fluidity under heating, alleviate the sedimentation of ceramic powder in the impregnation slurry, and is solid and non-sticky at room temperature.

[0030] The present invention also provides an impregnation slurry for prepreg, comprising a SiBCN precursor and a ceramic powder, wherein the mass fraction of the SiBCN precursor is 60% to 90%, and the mass fraction of the ceramic powder is 10% to 40wt%; the ceramic powder is one or more of hafnium carbide, zirconium carbide, tantalum carbide, silicon carbide, hafnium boride, zirconium boride, tantalum boride, hafnium nitride, zirconium nitride, tantalum nitride, etc., and the particle size is 500nm to 50μm. The impregnation slurry is solid at room temperature and is converted into a flowable liquid when heated.

[0031] The present invention also provides a prepreg, which includes a substrate and an impregnation slurry, wherein the impregnation slurry adopts the impregnation slurry containing SiBCN precursor and ceramic powder as described above; the substrate is a unidirectional fiber cloth or a two-dimensional fiber woven cloth, selected from quartz fiber, carbon fiber, ultra-high temperature ceramic fiber unidirectional fiber cloth or a two-dimensional fiber woven cloth.

[0032] The present invention also provides a method for preparing a prepreg, comprising:

[0033] The SiBCN precursor and the ceramic powder are heated and mixed to obtain an impregnation slurry;

[0034] The substrate is placed on a constant tension unwinding device and is pulled into a preheated dipping tank filled with impregnation slurry by the equipment. The substrate obtains a predetermined slurry content through a dipping amount control device. The prepared prepreg is then rolled up and refrigerated after being attached with a protective film.

[0035] Preferably, the preheating temperature of the impregnation slurry is 80-150° C., and the volume fraction of the impregnation slurry in the prepreg is 40%-70%.

[0036] The present invention also provides a fiber-reinforced resin-based composite material, comprising: using the above-mentioned prepreg to prepare a blank of a desired shape by winding, stacking and laying, and then preparing the fiber-reinforced resin-based composite material through vacuum-assisted curing and shaping.

[0037] The present invention also provides a fiber-reinforced ceramic-based composite material, comprising: using the above-mentioned prepreg to prepare a blank of a desired shape by winding, laminating and laying, etc., and preparing a fiber-reinforced resin-based composite material through vacuum-assisted curing and shaping; the fiber-reinforced resin-based composite material is subjected to a cracking reaction, and multiple rounds of precursor impregnation, curing, and cracking cycles are continued to obtain a densified ceramic-based composite material. The precursor used in the multiple rounds of precursor impregnation can be the SiBCN precursor prepared above, or other ceramic precursors, which are not limited here.

[0038] Example

[0039] Example 1

[0040] A method for preparing a fiber-reinforced resin-based composite material comprises the following steps:

[0041] Under the protection of inert atmosphere, 20L of n-hexane, 4.3kg (30.5mol) of reaction raw materials methylvinyldichlorosilane and 3.6kg (30.7mol) of boron trichloride were added to a 100L reactor, and 40kg (215.7mol) of 1,3-divinyltetramethyldisilazane was slowly added dropwise. After stirring evenly, the temperature was raised to react. The mixture was kept at 60, 80, 120 and 160°C for 1h, and then the temperature was raised to 250°C for 1h to obtain a room temperature viscous SiBCN resin. The room temperature viscosity of the precursor was 50000cp, and the number average molecular weight of the precursor was 8500.

[0042] Under the protection of an inert atmosphere, the SiBCN precursor was heated to 80° C., and then 20 wt % of hafnium carbide ceramic powder was added to the SiBCN resin and fully stirred, and then rapidly cooled at a temperature of −20° C. to obtain a mixed slurry.

[0043] The unidirectional carbon fiber is arranged in a constant tension unwinding device and is pulled into a dipping tank filled with impregnation slurry that has been preheated at 100°C. The impregnated fiber fabric is precisely controlled by a device to obtain a slurry content of 50wt%. The prepreg prepared is then rolled up and refrigerated for later use after being attached with a protective film.

[0044] The prepared unidirectional prepreg was laid in a 0-90° ply manner to obtain a composite blank with a thickness of 10 cm, and vacuum-assisted curing and shaping was performed in a metal tooling, and a special silicone resin-based composite material was obtained after curing at 180°C. After testing, the tensile strength of the composite material was 150MPa.

[0045] Example 2

[0046] A method for preparing a fiber-reinforced ceramic matrix composite material comprises the following steps:

[0047] Under the protection of inert atmosphere, 20L of n-hexane, 4.3kg of reaction raw materials methylvinyldichlorosilane and 3.6kg of boron trichloride were added to a 100L reactor, and 40kg of 1,3-divinyltetramethyldisilazane was slowly added dropwise. After stirring evenly, the temperature was raised to react. The mixture was kept at 60, 80, 120 and 160°C for 1h, and then the temperature was raised to 270°C and kept for 1h to obtain a room temperature solid SiBCN resin. The room temperature viscosity of the precursor was 100000cp, and the number average molecular weight of the precursor was 11000.

[0048] Under the protection of an inert atmosphere, the SiBCN precursor was heated to 80° C., and then 30 wt % of hafnium carbide ceramic powder was added to the SiBCN resin and fully stirred, and then rapidly cooled at a temperature of -20° C. to obtain a mixed slurry.

[0049] The unidirectional carbon fiber is arranged in a constant tension unwinding device and is pulled into a dipping tank filled with precursor mixed slurry that has been preheated to 120°C. The fiber fabric impregnated with resin obtains a slurry content of 60wt% through a precise control device for the amount of dipping. The prepreg prepared is then rolled up and refrigerated for later use after being attached with a protective film.

[0050] The prepared unidirectional prepreg was laid in a 0-90° layering manner to obtain a composite material blank with a thickness of 10 cm, and vacuum-assisted curing and shaping was carried out in a metal tooling. After curing at 180°C, a special silicone resin-based composite material was obtained.

[0051] The special silicone resin-based composite material was clamped in a graphite dimensional tooling and cracked at 1200°C for 1 hour in a heat treatment equipment to obtain a ceramic-based composite body. Subsequently, SiBCN resin with a viscosity of less than 200cp was selected to further pressurize the composite body for impregnation-curing-cracking. The impregnation pressure was 2MPa, the curing temperature was 180°C, and the cracking temperature was 1200°C. After 4 rounds of impregnation-curing-cracking, the hafnium-containing SiBCN ceramic-based composite material was finally obtained. The density of the composite material was measured to be 1.95g / cm 3 , tensile strength is 250MPa.

[0052] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0053] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for preparing a SiBCN precursor for prepreg, characterized in that: The method comprises the following steps: using methylvinyldichlorosilane, boron trichloride and disilazane as raw materials, reacting at a temperature of 220 to 280° C. to obtain a SiBCN precursor; Dichlorosilane has the following structure: Wherein, R1 and R2 are the same or different, and at least one of R1 and R2 contains an olefin group, and R1 and R2 are independently selected from the following groups: H, C 2-4 Olefin group.

2. The method for preparing a SiBCN precursor for prepreg according to claim 1, characterized in that: The preparation method specifically comprises: under the protection of an inert atmosphere, adding a solvent and reaction raw materials methylvinyldichlorosilane, boron trichloride and disilazane into a reaction kettle, stirring evenly and then heating to react, heat-insulating at 55-65, 75-85, 110-130 and 150-170°C for 0.5-1h, respectively, then heating to 220-280°C and heat-insulating for 0.1-10h to obtain a SiBCN resin that is viscous or solid at room temperature.

3. The method for preparing a SiBCN precursor for prepreg according to claim 1 or 2, characterized in that: The molar ratio of the methylvinyldichlorosilane, boron trichloride and disilazane is 1:0.5-2:4-10.

4. A SiBCN precursor for prepreg, characterized in that The prepreg is prepared by the method for preparing a SiBCN precursor for prepreg according to any one of claims 1 to 4; preferably, the room temperature viscosity of the precursor is 20,000 to 500,000 cp, and the number average molecular weight of the precursor is 4,000 to 20,000.

5. A prepreg impregnation slurry, characterized in that: It comprises the SiBCN precursor and ceramic powder as described in claim 4, the mass fraction of the SiBCN precursor is 60% to 90%, and the mass fraction of the ceramic powder is 10% to 40wt%; preferably, the ceramic powder is one or more of hafnium carbide, zirconium carbide, tantalum carbide, silicon carbide, hafnium boride, zirconium boride, tantalum boride, hafnium nitride, zirconium nitride, tantalum nitride, etc.

6. A prepreg, characterized in that: The prepreg comprises a substrate and an impregnation slurry, wherein the impregnation slurry is the impregnation slurry for prepreg according to claim 5, and the substrate is a unidirectional fiber cloth or a two-dimensional fiber woven cloth.

7. The prepreg according to claim 6, characterized in that The volume fraction of the impregnation slurry in the prepreg is 40% to 70%.

8. A method for preparing the prepreg according to claim 6, characterized in that: include: The SiBCN precursor and the ceramic powder are heated and mixed to obtain an impregnation slurry; The substrate is placed on a constant tension unwinding device and is pulled into a preheated dipping tank filled with impregnation slurry by the equipment. The substrate obtains a predetermined slurry content through a dipping amount control device. The prepared prepreg is then rolled up and refrigerated after being attached with a protective film.

9. A fiber-reinforced resin-based composite material, characterized in that: include: The prepreg according to claim 5 or 6 is used to prepare a blank of a desired shape by winding or stacking, and a fiber-reinforced resin-based composite material is prepared by vacuum-assisted curing and shaping.

10. A fiber-reinforced ceramic matrix composite material, characterized in that: include: The prepreg according to claim 5 or 6 is used to prepare a blank of a desired shape by winding or stacking, and a fiber-reinforced resin-based composite material is prepared by vacuum-assisted curing and shaping; The fiber-reinforced resin-based composite material is subjected to a cracking reaction, and multiple rounds of precursor impregnation, curing, and cracking cycles are continued to obtain a densified ceramic-based composite material.

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