Carborane hybrid RTM polyimide setting agent and preparation method thereof

Abstract

The invention belongs to the technical field of resin-based composite material manufacturing, and relates to a carborane hybrid RTM polyimide setting agent and a preparation method thereof. The molecular structure of the RTM forming polyimide setting agent is designed into an amide ester oligomer containing a carborane structure and active phenylethynyl, carborane diamine and aromatic diamine are added into an esterified anhydride solution, and the amide ester oligomer with the main chain containing carborane is generated through devolatilization polymerization. According to the carborane hybridized RTM polyimide setting agent, a cage-shaped carborane structure is introduced into a molecular main chain, the heat resistance of the polyimide setting agent can be effectively improved, the polyimide setting agent can be matched with RTM polyimide resin resistant to 400 DEG C or above for use, meanwhile, a low-boiling-point solvent is adopted as a reaction solvent, the production efficiency can be remarkably improved, and the process cost can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of resin-based composite material manufacturing, and relates to a carborane hybrid RTM polyimide setting agent and a preparation method thereof. Background Art

[0002] With the rapid development of aerospace technology at home and abroad, more and more high-temperature resistant polyimide composite parts are used in aerospace structures. Most of the mature structures are simple plane or curved structures using autoclave technology. Such complex structures are often difficult to achieve integral molding using traditional autoclave technology. Liquid-molded polyimide has been widely concerned and applied in the field of aeroengines 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 work, and has begun to verify and apply it in engine structures. At this stage, the temperature resistance of liquid-molded polyimide composite materials reported in research is generally lower than 350°C.

[0003] However, with the development of aerospace equipment such as high-speed missiles and hypersonic vehicles, the traditional autoclave molding process cannot meet the molding process requirements of its complex structure, and it is necessary to use RTM polyimide composite materials with a temperature resistance of more than 400°C for molding and manufacturing. However, the main molecular chain of the PETI type RTM polyimide resin developed by NASA is a pure organic structure. Even through molecular structure optimization design, it is difficult to meet the requirements of long-term service at 400°C. Invention patent ZL201518008675.6 discloses a preparation method for conventional polyimide molding, whose molecular structure is a pure organic structure. Although it can withstand a temperature of up to 350°C, it cannot withstand a temperature of 400°C for a long time. Summary of the invention

[0004] 1. Technical issues to be resolved

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

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a carborane hybrid RTM polyimide setting agent, wherein the carborane hybrid RTM polyimide setting agent comprises two structures, structure A or structure B;

[0008] The structure A includes the structure shown in formula I:

[0009]

[0010] The structure B includes the structure shown in formula II:

[0011]

[0012] In Formula I, X 1 represents any one of the following substituents:

[0013]

[0014]

[0015] In Formula II, X 2 represents any one of the following substituents:

[0016]

[0017] Wherein, R represents any one of the following substituents:

[0018]

[0019] Wherein, m is any integer from 1 to 5, and n is any integer from 1 to 5.

[0020] The present invention also provides a method for preparing an RTM polyimide setting agent, comprising the steps of:

[0021] S1. dissolving 4-phenylethynylbenzene anhydride in an alcohol solvent and subjecting the mixture to reflux reaction to obtain an esterification solution;

[0022] S2. Under inert gas protection, the carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixture solution;

[0023] S3. The mixture solution is heated and vacuum reacted to obtain a block polyimide setting agent;

[0024] S4. crushing the blocky polyimide setting agent to control the particle size, and obtaining a powdery carborane hybrid RTM polyimide setting agent.

[0025] As a preferred embodiment of the present invention, in step S1, the reaction temperature of the reflux reaction is 60°C-90°C, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

[0026] As a preferred embodiment of the present invention, in step S2, the stirring temperature is 25-80°C, and the stirring time is 1h-6h.

[0027] As a preferred embodiment of the present invention, in step S3, the heating vacuum reaction process is specifically to heat the mixture solution to 50-100°C, apply continuous vacuum to the reactor, control the volatilized solvent in the solution to no longer flow back into the reaction solution, and recover it through a solution recovery device. When the reaction reaches a solvent content of ≤2%, stop stirring, release the material using an extruder, and obtain a block polyimide setting agent after cooling.

[0028] As a preferred embodiment of the present invention, the powdered carborane hybrid RTM polyimide setting agent in step S4 has a particle size of 50 meshes to 100 meshes.

[0029] As 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.

[0030] As a preferred embodiment of the present invention, the carborane diamine monomer is a diaminophenyl carborane monomer.

[0031] As a preferred embodiment of the present invention, the alcohol solvent is one of methanol, ethanol, propanol, isopropanol, butanol, and n-butanol, or a mixture of any proportions of the above.

[0032] The invention also provides an application of a carborane hybrid RTM polyimide setting agent in preparing a pre-set fabric.

[0033] (III) Beneficial effects

[0034] The above technical solution of the present invention has the following advantages:

[0035] The present invention designs the molecular structure of the RTM molding polyimide setting agent into an amide ester oligomer containing a carborane structure and an active phenylethynyl group, uses an alcohol solvent as a reaction solvent, adds carborane diamine and aromatic diamine in the form of powder to an esterified acid anhydride solution, generates an amide ester oligomer containing carborane in the main chain through devolatilization polymerization under vacuum, and obtains a carborane hybrid RTM polyimide powder setting agent through mechanical crushing to control the particle size. The present invention introduces a cage-like carborane structure into the main chain of the molecule to form an organic-inorganic hybrid molecular structure, which can effectively improve the heat resistance of the polyimide setting agent, and improves the heat resistance of the setting agent to above 400°C, and can be used in conjunction with an RTM polyimide resin that can withstand temperatures above 400°C, providing material support for the molding and manufacturing of 400°C resistant RTM polyimide composite materials and components thereof. DETAILED DESCRIPTION

[0036] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] The present invention provides a carborane hybrid RTM polyimide setting agent, wherein the carborane hybrid RTM polyimide setting agent comprises two structures: structure A or structure B;

[0038] The structure A includes the structure shown in formula I:

[0039]

[0040] The structure B includes the structure shown in formula II:

[0041]

[0042] In Formula I, X 1 represents any one of the following substituents:

[0043]

[0044] In Formula II, X 2 represents any one of the following substituents:

[0045]

[0046]

[0047] Wherein, R represents any one of the following substituents:

[0048]

[0049] Wherein, m is any integer from 1 to 5, and n is any integer from 1 to 5.

[0050] The present invention also provides a method for preparing an RTM polyimide setting agent, comprising the steps of:

[0051] S1. dissolving 4-phenylethynylbenzene anhydride in an alcohol solvent and subjecting the mixture to reflux reaction to obtain an esterification solution;

[0052] S2. Under inert gas protection, the carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixture solution;

[0053] S3. The mixture solution is heated and vacuum reacted to obtain a block polyimide setting agent;

[0054] S4. crushing the blocky polyimide setting agent to control the particle size, and obtaining a powdery carborane hybrid RTM polyimide setting agent.

[0055] As a preferred embodiment of the present invention, in step S1, the reaction temperature of the reflux reaction is 60°C-90°C, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

[0056] As a preferred embodiment of the present invention, in step S2, the stirring temperature is 25-80°C, and the stirring time is 1h-6h.

[0057] As a preferred embodiment of the present invention, in step S3, the heating vacuum reaction process is specifically to heat the mixture solution to 50-100°C, apply continuous vacuum to the reactor, control the volatilized solvent in the solution to no longer flow back into the reaction solution, and recover it through a solution recovery device. When the reaction reaches a solvent content of ≤2%, stop stirring, release the material using an extruder, and obtain a block polyimide setting agent after cooling.

[0058] As a preferred embodiment of the present invention, the powdered carborane hybrid RTM polyimide setting agent in step S4 has a particle size of 50 meshes to 100 meshes.

[0059] As 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.

[0060] As a preferred embodiment of the present invention, the carborane diamine monomer is a diaminophenyl carborane monomer.

[0061] As a preferred embodiment of the present invention, the alcohol solvent is one of methanol, ethanol, propanol, isopropanol, butanol, and n-butanol, or a mixture of any proportions of the above.

[0062] The present invention designs the molecular structure of the RTM molding polyimide setting agent into an amide ester oligomer containing a carborane structure and an active phenylethynyl group, uses an alcohol solvent as a reaction solvent, adds carborane diamine and aromatic diamine in the form of powder to an esterified acid anhydride solution, generates an amide ester oligomer containing carborane in the main chain through devolatilization polymerization under vacuum, and obtains a carborane hybrid RTM polyimide powder setting agent through mechanical crushing to control the particle size. The present invention introduces a cage-like carborane structure into the main chain of the molecule to form an organic-inorganic hybrid molecular structure, which can effectively improve the heat resistance of the polyimide setting agent, and improves the heat resistance of the setting agent to above 400°C, and can be used in conjunction with an RTM polyimide resin that can withstand temperatures above 400°C, providing material support for the molding and manufacturing of 400°C resistant RTM polyimide composite materials and components thereof.

[0063] Example 1

[0064] This embodiment provides a carborane hybrid RTM polyimide setting agent, which is structure A, and the chemical structure is as follows:

[0065]

[0066] Chemical structure of hairspray 1

[0067] The preparation method of the carborane hybrid RTM polyimide setting agent provided in this embodiment comprises the steps of:

[0068] S1. Dissolve 269 g of 4-phenylethynylphthalic anhydride and 319 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride monomer in 880 g of methanol, and reflux for reaction at 78° C. for 3 h to obtain an esterified anhydride solution.

[0069] S2. Nitrogen was introduced into the obtained esterified anhydride solution, 354 g of dimethyl carborane diamine monomer and 59 g of meta-phenylenediamine (m-PDA) monomer powder were directly added to the above esterified solution, and stirred at 30° C. for 4 h to obtain a mixture solution.

[0070] S3. The mixture solution is heated to 80°C, a continuous vacuum is applied to the reactor, the volatile solvent in the solution is controlled to not flow back into the reaction solution, and the mixture is recovered by a solution recovery device. When the reaction reaches a solvent content of ≤2%, stirring is stopped, the material is discharged by an extruder, and a block-shaped polyimide setting agent is obtained after cooling.

[0071] S4. The obtained blocky polyimide setting agent is crushed by a crusher, and the particle size of the crushed setting agent is controlled to be 80 meshes to obtain a powdery carborane hybrid RTM polyimide setting agent, that is, the present invention.

[0072] The basic properties of the carborane hybrid RTM polyimide setting agent provided in this embodiment are shown in Table 1.

[0073] The shaping agent is evenly sprinkled on the surface of the carbon fiber fabric, two layers of carbon cloth are stacked, and an electric iron is used to heat and flatten them. After cooling, the two layers of carbon cloth are well bonded and not easy to come apart, meeting the requirements for the shaping effect of the carbon cloth.

[0074] Table 1 Basic properties of setting agent

[0075] Serial number Test items performance 1 Softening point of setting agent, ℃ 112℃ 2 Glass transition temperature of setting agent, ℃ 516℃

[0076] Example 2

[0077] This embodiment provides a carborane hybrid RTM polyimide setting agent, which is structure B, and the chemical structure is as follows:

[0078]

[0079] Chemical structure of hairspray 2

[0080] The preparation method of the carborane hybrid RTM polyimide setting agent provided in this embodiment comprises the steps of:

[0081] S1. 305 g of 4-phenylethynylphthalic anhydride and 362 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride monomer were dissolved in 1000 g of ethanol, and refluxed at 78° C. for 3 h to obtain an esterified anhydride solution.

[0082] S2. Nitrogen was introduced into the obtained esterified anhydride solution, 133 g of dimethyl carborane diamine monomer and 201 g of meta-phenylenediamine (m-PDA) monomer powder were directly added to the above esterified solution, and stirred at 30° C. for 5 h to obtain a mixture solution.

[0083] S3. The mixture solution is heated to 85°C, and a continuous vacuum is applied to the reactor to control the volatile solvent in the solution to not flow back into the reaction solution, and the mixture is recovered through a solution recovery device. When the reaction reaches a solvent content of ≤2%, stirring is stopped, and the material is discharged using an extruder. After cooling, a block-shaped polyimide setting agent is obtained.

[0084] S4. The obtained blocky polyimide setting agent is crushed by a crusher, and the particle size of the crushed setting agent is controlled to be 80 meshes to obtain a powdered carborane hybrid RTM polyimide setting agent, that is, the present invention.

[0085] The basic properties of the carborane hybrid RTM polyimide setting agent provided in this embodiment are shown in Table 2.

[0086] The shaping agent is evenly sprinkled on the surface of the carbon fiber fabric, two layers of carbon cloth are stacked, and an electric iron is used to heat and flatten them. After cooling, the two layers of carbon cloth are well bonded and not easy to come apart, meeting the requirements for the shaping effect of the carbon cloth.

[0087] Table 2 Basic properties of setting agent

[0088] Serial number Test items performance 1 Softening point of setting agent, ℃ 108℃ 2 Glass transition temperature of setting agent, ℃ 506℃

[0089] Example 3

[0090] This embodiment provides a carborane hybrid RTM polyimide setting agent, which is structure A, and the chemical structure is as follows:

[0091]

[0092] Chemical structure of hairspray 3

[0093] The preparation method of the carborane hybrid RTM polyimide setting agent provided in this embodiment comprises the steps of:

[0094] S1. Dissolve 269 g of 4-phenylethynylphthalic anhydride and 319 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride monomer in 880 g of ethanol, and reflux for reaction at 65° C. for 4 h to obtain an esterified anhydride solution.

[0095] S2. Nitrogen was introduced into the obtained esterified anhydride solution, 354 g of dimethyl carborane diamine monomer and 59 g of meta-phenylenediamine (m-PDA) monomer powder were directly added to the above esterified solution, and stirred at 30° C. for 4 h to obtain a mixture solution.

[0096] S3. The mixture solution is heated to 70°C, a continuous vacuum is applied to the reactor, the volatile solvent in the solution is controlled to not flow back into the reaction solution, and the mixture is recovered by a solution recovery device. When the reaction reaches a solvent content of ≤2%, stirring is stopped, the material is discharged by an extruder, and a block-shaped polyimide setting agent is obtained after cooling.

[0097] S4. The obtained blocky polyimide setting agent is crushed by a pulverizer, and the particle size of the crushed setting agent is controlled to be 100 meshes to obtain a powdered carborane hybrid RTM polyimide setting agent, that is, the present invention.

[0098] The basic properties of the carborane hybrid RTM polyimide setting agent provided in this embodiment are shown in Table 3.

[0099] The shaping agent is evenly sprinkled on the surface of the carbon fiber fabric, two layers of carbon cloth are stacked, and an electric iron is used to heat and flatten them. After cooling, the two layers of carbon cloth are well bonded and not easy to come apart, meeting the requirements for the shaping effect of the carbon cloth.

[0100] Table 3 Basic properties of setting agent

[0101] Serial number Test items performance 1 Softening point of setting agent, ℃ 109℃ 2 Glass transition temperature of setting agent, ℃ 512℃

[0102] Example 4

[0103] This embodiment provides a carborane hybrid RTM polyimide setting agent, which is structure A, and the chemical structure is as follows:

[0104]

[0105] Chemical structure of hairspray 4

[0106] The preparation method of the carborane hybrid RTM polyimide setting agent provided in this embodiment comprises the steps of:

[0107] S1. 253 g of 4-phenylethynylphthalic anhydride and 300 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride monomer were dissolved in 829 g of propanol, and refluxed at 100° C. for 5 h to obtain an esterified anhydride solution.

[0108] S2. Nitrogen was introduced into the obtained esterified anhydride solution, 333 g of dimethyl carborane diamine monomer and 114 g of 2-(3-aminophenyl)-5-aminobenzimidazole (2,3,5-AABI) monomer powder were directly added to the above esterified solution, and stirred at 35° C. for 5 h to obtain a mixture solution.

[0109] S3. The mixture solution is heated to 100°C, a continuous vacuum is applied to the reactor, the volatilized solvent in the solution is controlled to not flow back into the reaction solution, and the solvent is recovered through a solution recovery device. When the reaction reaches a solvent content of ≤2%, stirring is stopped, the material is discharged using an extruder, and a block-shaped polyimide setting agent is obtained after cooling.

[0110] S4. The obtained blocky polyimide setting agent is crushed by a crusher, and the particle size of the crushed setting agent is controlled to be 70 meshes to obtain a powdered carborane hybrid RTM polyimide setting agent, that is, the present invention.

[0111] The basic properties of the carborane hybrid RTM polyimide setting agent provided in this embodiment are shown in Table 4.

[0112] The shaping agent is evenly sprinkled on the surface of the carbon fiber fabric, two layers of carbon cloth are stacked, and an electric iron is used to heat and flatten them. After cooling, the two layers of carbon cloth are well bonded and not easy to come apart, meeting the requirements for the shaping effect of the carbon cloth.

[0113] Table 4 Basic properties of setting agent

[0114] Serial number Test items performance 1 Softening point of setting agent, ℃ 116℃ 2 Glass transition temperature of setting agent, ℃ 526℃

[0115] Example 5

[0116] This embodiment provides a carborane hybrid RTM polyimide setting agent, which is structure B, and the chemical structure is as follows:

[0117]

[0118] Chemical structure of hairspray 5

[0119] The preparation method of the carborane hybrid RTM polyimide setting agent provided in this embodiment comprises the steps of:

[0120] S1. Dissolve 236 g of 4-phenylethynylphthalic anhydride and 279 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride monomer in 772 g of propanol, and reflux at 100° C. for 5 h to obtain an esterified anhydride solution.

[0121] S2. Then, nitrogen gas was introduced into the above solution, and 155 g of dimethyl carborane diamine monomer and 331 g of 9,9-bis(4-aminophenyl)fluorene (FDA) monomer powder were directly added to the above esterification solution, and stirred at 35° C. for 5 h to obtain a mixture solution.

[0122] S3. The mixture solution is heated to 95°C, a continuous vacuum is applied to the reactor, the volatile solvent in the solution is controlled to not flow back into the reaction solution, and the mixture is recovered through a solution recovery device. When the reaction reaches a solvent content of ≤2%, stirring is stopped, the material is discharged using an extruder, and a block-shaped polyimide setting agent is obtained after cooling.

[0123] S4. The obtained blocky polyimide setting agent is crushed by a crusher, and the particle size of the crushed setting agent is controlled to be 90 meshes to obtain a powdered carborane hybrid RTM polyimide setting agent, that is, the present invention.

[0124] The basic properties of the carborane hybrid RTM polyimide setting agent provided in this embodiment are shown in Table 5.

[0125] The shaping agent is evenly sprinkled on the surface of the carbon fiber fabric, two layers of carbon cloth are stacked, and an electric iron is used to heat and flatten them. After cooling, the two layers of carbon cloth are well bonded and not easy to come apart, meeting the requirements for the shaping effect of the carbon cloth.

[0126] Table 5 Basic properties of setting agent

[0127] Serial number Test items performance 1 Softening point of setting agent, ℃ 118℃ 2 Glass transition temperature of setting agent, ℃ 496℃

[0128] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. For the embodiments of the method, the relevant parts can refer to the partial description of the device embodiment (adopted according to the writing situation). The present invention is not limited to the structure described above. In addition, for the sake of brevity, the detailed description of the known method technology is omitted here.

[0129] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A carborane hybrid RTM polyimide setting agent, characterized in that: The carborane hybrid RTM polyimide setting agent includes two structures, structure A or structure B; The structure A includes the structure shown in formula I: The structure B includes the structure shown in formula II: In formula I, X1 represents any one of the following substituents: In formula II, X2 represents any one of the following substituents: Wherein, R represents any one of the following substituents: Wherein, m is any integer from 1 to 5, and n is any integer from 1 to 5.

2. A method for preparing the RTM polyimide setting agent according to claim 1, characterized in that: Includes steps: S1. dissolving 4-phenylethynylbenzene anhydride in an alcohol solvent and subjecting the mixture to reflux reaction to obtain an esterification solution; S2. Under inert gas protection, the carborane diamine monomer and conventional diamine monomer powder are added to the esterification solution and stirred to obtain a mixture solution; S3. The mixture solution is heated and vacuum reacted to obtain a block polyimide setting agent; S4. crushing the blocky polyimide setting agent to control the particle size, and obtaining a powdery carborane hybrid RTM polyimide setting agent.

3. The method for preparing the RTM polyimide setting agent according to claim 2, characterized in that: In step S1, the reaction temperature of the reflux reaction is 60°C-90°C, the reaction time is 1h-6h, and the concentration of the obtained esterification solution is 40%-80%wt.

4. The method for preparing the RTM polyimide setting agent according to claim 2 or 3, characterized in that: In step S2, the stirring temperature is 25-80°C, and the stirring time is 1h-6h.

5. The method for preparing the RTM polyimide setting agent according to claim 2 or 4, characterized in that: In step S3, the heating vacuum reaction process is specifically to heat the mixture solution to 50-100° C., maintain vacuum, and when the reaction reaches a solvent content of ≤2%, stop stirring, release the material, and obtain a block-shaped polyimide setting agent after cooling.

6. The method for preparing the RTM polyimide setting agent as claimed in claim 2, characterized in that: The particle size of the powdered carborane hybrid RTM polyimide setting agent in step S4 is 50 mesh to 100 mesh.

7. The method for preparing the RTM polyimide setting agent as claimed in claim 2, characterized in that: 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.

8. The method for preparing the RTM polyimide setting agent as claimed in claim 2, characterized in that: The carborane diamine monomer is a diaminophenyl carborane monomer.

9. The method for preparing the RTM polyimide setting agent as claimed in claim 2, characterized in that: The alcohol solvent is one of methanol, ethanol, propanol, isopropanol, butanol, and n-butanol, or a mixture of any proportion of the above.

10. Use of a carborane hybrid RTM polyimide setting agent as claimed in claim 1 in the preparation of pre-set fabrics.

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