A carborane hybrid RTM polyimide sizing agent and its preparation method

Abstract

This invention belongs to the field of resin-based composite material manufacturing technology, and relates to a carborane hybrid RTM polyimide stabilizer and its preparation method. This invention designs the molecular structure of the RTM molding polyimide stabilizer as an amide ester oligomer containing a carborane structure and an active phenylacetylene group. Carborane diamine and aromatic diamine are added to an esterified acid anhydride solution, and devolatilization polymerization is performed to generate an amide ester oligomer with a carborane-containing main chain. The carborane hybrid RTM polyimide stabilizer of this invention introduces a cage-like carborane structure into the molecular backbone, which can effectively improve the heat resistance of the polyimide stabilizer, enabling it to be used with RTM polyimide resins that withstand temperatures above 400℃. Simultaneously, the use of a low-boiling-point solvent as the reaction solvent can significantly improve production efficiency and reduce process costs.

Description

Technical Field

[0001] This invention belongs to the field of resin-based composite material manufacturing technology, and relates to a carborane hybrid RTM polyimide sizing agent and its preparation method. Background Technology

[0002] With the rapid development of aerospace technology at home and abroad, more and more high-temperature resistant polyimide composite materials are being used in aerospace structures. Most of the structures that have been successfully applied are simple planar or curved structures using autoclave technology. These complex structures are often difficult to integrally form using traditional autoclave technology. Liquid-molded polyimide has received widespread attention and application in the field of aero-engines due to its excellent performance characteristics. As early as the 1990s, NASA developed typical RTM-molded polyimide resin grades such as PETI-RTM, PETI-298, PETI-330, and PETI-375 and carried out a lot of application research. It has already begun to be verified and applied in engine structures. At present, the temperature resistance of liquid-molded polyimide composite materials reported in research is generally below 350℃.

[0003] However, with the development of aerospace equipment such as high-speed missiles and hypersonic vehicles, traditional autoclave molding processes cannot meet the molding requirements of their complex structures. It is necessary to use RTM polyimide composite materials that can withstand temperatures above 400°C for molding and manufacturing. However, the molecular backbone of the PETI type RTM polyimide resin developed by NASA is a pure organic structure. Even with molecular structure optimization design, it is difficult to meet the requirements of long-term service at 400°C. Invention patent ZL201518008675.6 discloses a conventional polyimide shaping preparation method. Its molecular structure is a pure organic structure. Although it can withstand temperatures up to 350°C, it cannot withstand temperatures of 400°C for a long time. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by the present invention is to provide material support for the preparation of RTM polyimide composite preforms with a temperature resistance of over 400°C, so as to meet the application requirements of large-size complex high-temperature resistant structures with a temperature resistance of over 400°C.

[0006] (II) Technical Solution

[0007] To solve the above technical problems, the present invention provides an amide ester oligomer sizing agent with a main chain containing carborane, wherein the sizing agent has the structural formula of structure A or structure B;

[0008] Structure A includes the structure shown in Formula I:

[0009]

[0010] Formula I

[0011] Structure B includes the structure shown in Formula II:

[0012]

[0013] Formula II

[0014] In Formula I, X1 represents any of the following substituents:

[0015] , , , , , , , , ,

[0016] In Formula II, X2 represents any of the following substituents:

[0017] , , , , , , , , , ;

[0018] Wherein, R represents any of the following substituents:

[0019] , , , , , ;

[0020] Where m takes any integer from 1 to 5, and n takes any integer from 1 to 5.

[0021] This invention also provides a method for preparing an amide ester oligomer stabilizer with a main chain containing carborane, comprising the following steps:

[0022] S1. Dissolve 4-phenylacetylene phthalic anhydride in an alcohol solvent and reflux to obtain an esterified solution;

[0023] S2. Under inert gas protection, carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixed solution;

[0024] S3. The mixture solution is heated and subjected to a vacuum reaction to obtain a block-shaped shaping agent;

[0025] S4. Crush the block-shaped sizing agent, control the particle size, and obtain a powdered sizing agent.

[0026] In a preferred embodiment of the present invention, in step S1, the reaction temperature of the reflux reaction is 60℃-90℃, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

[0027] In a preferred embodiment of the present invention, in step S2, the stirring temperature is 25-80°C and the stirring time is 1-6 hours.

[0028] In a preferred embodiment of the present invention, in step S3, the heating vacuum reaction process specifically involves heating the mixed solution to 50-100°C, applying a continuous vacuum to the reaction vessel, controlling the solvent volatilized in the solution to no longer flow back into the reaction solution, and recovering it through a solution recovery device. When the solvent content is ≤2%, stirring is stopped, the material is released using an extrusion device, and after cooling, a block-shaped sizing agent is obtained.

[0029] In a preferred embodiment of the present invention, the particle size of the powdered sizing agent in step S4 is 50-100 mesh.

[0030] In a preferred embodiment of the present invention, the conventional diamine monomer is selected from one or two of m-PDA, 3,4-ODA, p-PDA, 6FAP, TFMBZ, 1,3,4-APB, p-ODA, FDA, 2,3,5-AABI, and 2,4,5-AABO.

[0031] In a preferred embodiment of the present invention, the carborane diamine monomer is a diaminophenyl carborane monomer.

[0032] In a preferred embodiment of the present invention, the alcohol solvent is one or a mixture of several of methanol, ethanol, propanol, isopropanol, butanol, and n-butanol in any proportion.

[0033] The present invention also provides an application of an amide ester oligomer stabilizer containing carborane in the main chain in the preparation of pre-shaped fabrics.

[0034] (III) Beneficial Effects

[0035] The above-described technical solution of the present invention has the following advantages:

[0036] This invention designs the molecular structure of a carborane-containing amide ester oligomer sizing agent into an amide ester oligomer containing a carborane structure and an active phenylacetylene group. Using an alcohol solvent as the reaction solvent, carborane diamine and aromatic diamine are added in powder form to an esterified acid anhydride solution. Under vacuum, devolatilization polymerization is carried out to generate a carborane-containing amide ester oligomer. The particle size is then controlled by mechanical pulverization to obtain a powdered sizing agent. This invention introduces a cage-like carborane structure into the molecular backbone, forming an organic-inorganic hybrid molecular structure, which effectively improves the heat resistance of the sizing agent, raising its heat resistance to above 400℃. This allows it to be used in conjunction with RTM polyimide resins that can withstand temperatures above 400℃, providing material support for the molding and manufacturing of 400℃-resistant RTM polyimide composites and components. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0038] This invention provides an amide ester oligomer sizing agent with a main chain containing carborane, wherein the sizing agent has a structural formula of structure A or structure B;

[0039] Structure A includes the structure shown in Formula I:

[0040]

[0041] Formula I

[0042] Structure B includes the structure shown in Formula II:

[0043]

[0044] Formula II

[0045] In Formula I, X1 represents any of the following substituents:

[0046] , , , , , , , , ,

[0047] In Formula II, X2 represents any of the following substituents:

[0048] , , , , , , , , , ;

[0049] Wherein, R represents any of the following substituents:

[0050] , , , , , ;

[0051] Where m takes any integer from 1 to 5, and n takes any integer from 1 to 5.

[0052] This invention also provides a method for preparing an amide ester oligomer stabilizer with a main chain containing carborane, comprising the following steps:

[0053] S1. Dissolve 4-phenylacetylene phthalic anhydride in an alcohol solvent and reflux to obtain an esterified solution;

[0054] S2. Under inert gas protection, carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixed solution;

[0055] S3. The mixture solution is heated and subjected to a vacuum reaction to obtain a block-shaped shaping agent;

[0056] S4. Crush the block-shaped sizing agent, control the particle size, and obtain a powdered sizing agent.

[0057] In a preferred embodiment of the present invention, in step S1, the reaction temperature of the reflux reaction is 60℃-90℃, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

[0058] In a preferred embodiment of the present invention, in step S2, the stirring temperature is 25-80°C and the stirring time is 1-6 hours.

[0059] In a preferred embodiment of the present invention, in step S3, the heating vacuum reaction process specifically involves heating the mixed solution to 50-100°C, applying a continuous vacuum to the reaction vessel, controlling the solvent volatilized in the solution to no longer flow back into the reaction solution, and recovering it through a solution recovery device. When the solvent content is ≤2%, stirring is stopped, the material is released using an extrusion device, and after cooling, a block-shaped sizing agent is obtained.

[0060] In a preferred embodiment of the present invention, the particle size of the powdered sizing agent in step S4 is 50-100 mesh.

[0061] In a preferred embodiment of the present invention, the conventional diamine monomer is selected from one or two of m-PDA, 3,4-ODA, p-PDA, 6FAP, TFMBZ, 1,3,4-APB, p-ODA, FDA, 2,3,5-AABI, and 2,4,5-AABO.

[0062] In a preferred embodiment of the present invention, the carborane diamine monomer is a diaminophenyl carborane monomer.

[0063] In a preferred embodiment of the present invention, the alcohol solvent is one or a mixture of several of methanol, ethanol, propanol, isopropanol, butanol, and n-butanol in any proportion.

[0064] This invention designs the molecular structure of a carborane-containing amide ester oligomer sizing agent into an amide ester oligomer containing a carborane structure and an active phenylacetylene group. Using an alcohol solvent as the reaction solvent, carborane diamine and aromatic diamine are added in powder form to an esterified acid anhydride solution. Under vacuum, devolatilization polymerization is carried out to generate a carborane-containing amide ester oligomer. The particle size is then controlled by mechanical pulverization to obtain a powdered sizing agent. This invention introduces a cage-like carborane structure into the molecular backbone, forming an organic-inorganic hybrid molecular structure, which effectively improves the heat resistance of the sizing agent, raising its heat resistance to above 400℃. This allows it to be used in conjunction with RTM polyimide resins that can withstand temperatures above 400℃, providing material support for the molding and manufacturing of 400℃-resistant RTM polyimide composites and components.

[0065] Example 1

[0066] This embodiment provides an amide ester oligomer sizing agent with a main chain containing carborane, which is structure A, and its chemical structure is shown below:

[0067] Chemical structure of the setting agent 1

[0068] The method for preparing the amide ester oligomer stabilizer containing carborane in the main chain provided in this embodiment includes the following steps:

[0069] S1. Dissolve 269g of 4-phenylacetylene phthalic anhydride and 319g of 2,3,3',4'-biphenyltetraic acid dianhydride monomer in 880g of ethanol, and reflux at 78℃ for 3h to obtain an esterified anhydride solution.

[0070] S2. Nitrogen gas is introduced into the obtained esterified anhydride solution, and 354g of carborane diamine monomer and 59g of m-phenylenediamine (m-PDA) monomer powder are directly added to the above esterification solution. The mixture is stirred at 30°C for 4 hours to obtain a mixed solution.

[0071] S3. Heat the above mixture solution to 80°C, apply a continuous vacuum to the reactor, control the solvent volatilized in the solution to prevent it from flowing back into the reaction solution, and recover it through a solution recovery device. When the solvent content is ≤2%, stop stirring, release the material using an extrusion device, and obtain a block-shaped sizing agent after cooling.

[0072] S4. The obtained block-shaped sizing agent is pulverized using a pulverizer, and the particle size of the pulverized sizing agent is controlled to be 80 mesh to obtain a powdered sizing agent, which is the present invention.

[0073] The basic properties of the setting agent provided in this embodiment are shown in Table 1.

[0074] The setting agent is evenly sprinkled on the surface of the carbon fiber fabric. Two layers of carbon cloth are stacked, heated and flattened with an electric iron. After cooling, the two layers of carbon cloth are well bonded and not easy to separate, thus meeting the requirements for carbon cloth setting effect.

[0075] Table 1 Basic Properties of Fixatives

[0076]

[0077] Example 2

[0078] This embodiment provides an amide ester oligomer sizing agent with a main chain containing carborane, which is structure B, and its chemical structure is shown below:

[0079]

[0080] Chemical structure of the setting agent 2

[0081] The method for preparing the amide ester oligomer stabilizer containing carborane in the main chain provided in this embodiment includes the following steps:

[0082] S1. Dissolve 305g of 4-phenylacetylene phthalic anhydride and 362g of 2,3,3',4'-biphenyltetraic acid dianhydride monomer in 1000g of ethanol and reflux at 78℃ for 3h to obtain an esterified anhydride solution.

[0083] S2. Nitrogen gas is introduced into the obtained esterified anhydride solution, and 133g of carborane diamine monomer and 201g of m-phenylenediamine (m-PDA) monomer powder are directly added to the above esterification solution. The mixture is stirred at 30°C for 5 hours to obtain a mixed solution.

[0084] S3. Heat the above mixture solution to 85°C, apply a continuous vacuum to the reactor, control the solvent volatilized in the solution to prevent it from flowing back into the reaction solution, and recover it through a solution recovery device. When the solvent content is ≤2%, stop stirring, release the material using an extrusion device, and obtain a block-shaped sizing agent after cooling.

[0085] S4. The obtained block-shaped sizing agent is pulverized using a pulverizer, and the particle size of the pulverized sizing agent is controlled to be 80 mesh to obtain a powdered sizing agent, which is the present invention.

[0086] The basic properties of the setting agent provided in this embodiment are shown in Table 2.

[0087] The setting agent is evenly sprinkled on the surface of the carbon fiber fabric. Two layers of carbon cloth are stacked, heated and flattened with an electric iron. After cooling, the two layers of carbon cloth are well bonded and not easy to separate, thus meeting the requirements for carbon cloth setting effect.

[0088] Table 2 Basic Properties of Shaping Agents

[0089]

[0090] Example 3

[0091] This embodiment provides an amide ester oligomer sizing agent with a main chain containing carborane, which is structure A, and its chemical structure is shown below:

[0092]

[0093] Chemical structure of the setting agent 3

[0094] The method for preparing the amide ester oligomer stabilizer containing carborane in the main chain provided in this embodiment includes the following steps:

[0095] S1. Dissolve 269g of 4-phenylacetylene phthalic anhydride and 319g of 2,3,3',4'-biphenyltetraic acid dianhydride monomer in 880g of methanol, and reflux at 65℃ for 4h to obtain an esterified anhydride solution.

[0096] S2. Nitrogen gas is introduced into the obtained esterified anhydride solution, and 354g of carborane diamine monomer and 59g of m-phenylenediamine (m-PDA) monomer powder are directly added to the above esterification solution. The mixture is stirred at 30°C for 4 hours to obtain a mixed solution.

[0097] S3. Heat the above mixture solution to 70°C, apply a continuous vacuum to the reactor, control the solvent volatilized in the solution to prevent it from flowing back into the reaction solution, and recover it through a solution recovery device. When the solvent content is ≤2%, stop stirring, release the material using an extrusion device, and obtain a block-shaped sizing agent after cooling.

[0098] S4. The obtained block-shaped sizing agent is pulverized using a pulverizer, and the particle size of the pulverized sizing agent is controlled to be 100 mesh to obtain a powdered sizing agent, which is the present invention.

[0099] The basic properties of the setting agent provided in this embodiment are shown in Table 3.

[0100] The setting agent is evenly sprinkled on the surface of the carbon fiber fabric. Two layers of carbon cloth are stacked, heated and flattened with an electric iron. After cooling, the two layers of carbon cloth are well bonded and not easy to separate, thus meeting the requirements for carbon cloth setting effect.

[0101] Table 3 Basic Properties of Shaping Agents

[0102]

[0103] Example 4

[0104] This embodiment provides an amide ester oligomer sizing agent with a main chain containing carborane, which is structure A, and its chemical structure is shown below:

[0105]

[0106] Chemical structure of the setting agent 4

[0107] The method for preparing the amide ester oligomer stabilizer containing carborane in the main chain provided in this embodiment includes the following steps:

[0108] S1. Dissolve 253g of 4-phenylacetylene phthalic anhydride and 300g of 2,3,3',4'-biphenyltetraic acid dianhydride monomer in 829g of propanol, and reflux at 100℃ for 5h to obtain an esterified anhydride solution.

[0109] S2. Nitrogen gas is introduced into the obtained esterified anhydride solution. 333g of carborane diamine monomer and 114g of 2-(3-aminophenyl)-5-aminobenzimidazole (2,3,5-AABI) monomer powder are directly added to the above esterification solution and stirred at 35°C for 5h to obtain a mixed solution.

[0110] S3. Heat the above mixture solution to 100°C, apply a continuous vacuum to the reactor, control the solvent volatilized in the solution to prevent it from flowing back into the reaction solution, and recover it through a solution recovery device. When the solvent content is ≤2%, stop stirring, release the material using an extrusion device, and obtain a block-shaped sizing agent after cooling.

[0111] S4. The obtained block-shaped sizing agent is pulverized using a pulverizer, and the particle size of the pulverized sizing agent is controlled to be 70 mesh to obtain a powdered sizing agent, which is the present invention.

[0112] The basic properties of the setting agent provided in this embodiment are shown in Table 4.

[0113] The setting agent is evenly sprinkled on the surface of the carbon fiber fabric. Two layers of carbon cloth are stacked, heated and flattened with an electric iron. After cooling, the two layers of carbon cloth are well bonded and not easy to separate, thus meeting the requirements for carbon cloth setting effect.

[0114] Table 4 Basic Properties of Shaping Agents

[0115]

[0116] Example 5

[0117] This embodiment provides an amide ester oligomer sizing agent with a main chain containing carborane, which is structure B, and its chemical structure is shown below:

[0118]

[0119] Chemical structure of the setting agent 5

[0120] The method for preparing the amide ester oligomer stabilizer containing carborane in the main chain provided in this embodiment includes the following steps:

[0121] S1. Dissolve 236g of 4-phenylacetylene phthalic anhydride and 279g of 2,3,3',4'-biphenyltetraic acid dianhydride monomer in 772g of propanol, and reflux at 100℃ for 5h to obtain an esterified anhydride solution.

[0122] S2. Then, nitrogen gas is introduced into the above solution, and 155g of carborane diamine monomer and 331g of 9,9-bis(4-aminophenyl)fluorene (FDA) monomer powder are directly added to the above esterification solution. The mixture is stirred at 35°C for 5 hours to obtain a mixed solution.

[0123] S3. Heat the above mixture solution to 95°C, apply a continuous vacuum to the reactor, control the solvent volatilized in the solution to prevent it from flowing back into the reaction solution, and recover it through a solution recovery device. When the solvent content is ≤2%, stop stirring, release the material using an extrusion device, and obtain a block-shaped sizing agent after cooling.

[0124] S4. The obtained block-shaped sizing agent is pulverized using a pulverizer, and the particle size of the pulverized sizing agent is controlled to be 90 mesh to obtain a powdered sizing agent, which is the present invention.

[0125] The basic properties of the setting agent provided in this embodiment are shown in Table 5.

[0126] The setting agent is evenly sprinkled on the surface of the carbon fiber fabric. Two layers of carbon cloth are stacked, heated and flattened with an electric iron. After cooling, the two layers of carbon cloth are well bonded and not easy to separate, thus meeting the requirements for carbon cloth setting effect.

[0127] Table 5 Basic Properties of Sterilizers

[0128]

[0129] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A carborane-containing amide ester oligomer stabilizer, characterized in that, The structural formula of the setting agent is either structure A or structure B; Structure A is the structure shown in Equation I: A Formula I Structure B is the structure shown in Formula II: B Formula II In Formula I, X1 represents any of the following substituents: 、 ； In Formula II, X2 represents any of the following substituents: 、 ； Wherein, R represents any of the following substituents: 、 、 、 、 、 ； Where m takes any integer from 2 to 5, and n takes any integer from 2 to 5; The setting agent is prepared by the following steps: S1. Dissolve 4-phenylacetylene phthalic anhydride in an alcohol solvent and reflux to obtain an esterified solution; S2. Under inert gas protection, carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixed solution; S3. The mixture solution is heated and subjected to a vacuum reaction to obtain a block-shaped shaping agent; S4. Crush the block-shaped sizing agent, control the particle size, and obtain a powdered sizing agent.

2. The setting agent as described in claim 1, characterized in that, In step S1, the reflux reaction temperature is 60℃-90℃, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

3. The setting agent as described in claim 1, characterized in that, In step S2, the stirring temperature is 25-80℃, and the stirring time is 1h-6h.

4. The setting agent as described in claim 1, characterized in that, In step S3, the heating vacuum reaction process specifically involves heating the mixture solution to 50-100°C, maintaining a vacuum, stopping stirring when the solvent content is ≤2%, releasing the material, and obtaining a block-shaped sizing agent after cooling.

5. The setting agent as described in claim 1, characterized in that, The powdered sizing agent in step S4 has a particle size of 50-100 mesh.

6. The setting agent as described in claim 1, characterized in that, The alcohol solvent is one or a mixture of several of methanol, ethanol, propanol, and butanol in any proportion.

7. The application of the amide ester oligomer stabilizer containing carborane as described in claim 1 in the preparation of pre-shaped fabrics.

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