A thermoplastic polyimide resin toughener with both hydrophilic and hydrophobic properties and a preparation method thereof

Abstract

The application belongs to the technical field of polymer material preparation, and relates to a thermoplastic polyimide resin toughening agent with hydrophilic and hydrophobic properties and a preparation method thereof. The glass transition temperature of the thermoplastic polyimide resin toughening agent is increased to above 250 DEG C, and the toughening agent has the molecular structure characteristics of hydrophilic and hydrophobic properties, that is, the flexible part of the toughening agent molecular chain is soluble and similar to the molecular structure of the thermosetting polyimide resin, and the rigid part is insoluble in the thermoplastic polyimide resin. After the thermoplastic polyimide resin toughening agent is mixed with the thermosetting polyimide resin at high temperature, the particle morphology of the thermoplastic resin can be partially retained, so that the purpose of soluble-insoluble synergistic toughening is achieved, and the high-temperature resistance of the thermosetting polyimide resin is realized.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, and relates to a thermoplastic polyimide resin toughening agent with both affinity and hydrophobicity and its preparation method. Background Technology

[0002] Currently, toughening methods for thermosetting polyimide resins mainly include resin backbone molecular structure design, inorganic powder blending toughening, and thermoplastic resin toughening. Specifically, backbone molecular structure design refers to introducing flexible long chains containing ether bonds, sulfone groups, etc., into the thermosetting polyimide molecular structure during resin synthesis to increase the flexibility of the molecular backbone and improve resin toughness. However, for material development, this process usually requires repeated trial and error, is lengthy, and costly. Adding inorganic powders such as SiO2 to thermosetting polyimide resins can also improve resin brittleness to some extent and act as anchoring sites for the resin matrix under destructive loads, thus playing a toughening role. However, the physical connection between the resin and inorganic powders is only formed through resin wetting, and the inorganic powders are prone to agglomeration, requiring further surface treatment before they can be used as toughening components. This is inefficient and difficult to meet the needs of engineering applications. Thermoplastic resins include a series of thermoplastic polymers with different operating temperature ranges, such as polyethersulfone, polyetheretherketone, and thermoplastic polyimide. Among them, thermoplastic polyimide resin has a long-term operating temperature above 200°C, so it is used as a toughening material for thermosetting resins such as high-temperature epoxy, bismaleimide, and thermosetting polyimide to improve the toughness of thermosetting resins while ensuring the heat resistance of thermosetting resins.

[0003] For different thermosetting resin matrices, thermoplastic polyimide resin toughening agents with toughness, heat resistance, and system compatibility should be selected as toughening components. Therefore, it is necessary to design thermoplastic polyimide resin toughening agents tailored to the specific molecular structure of the thermosetting resin to ensure compatibility between the thermosetting resin and the thermoplastic toughening agent, achieving the best toughening effect. For example, patent CN 113861421 discloses a block-type thermoplastic polyimide resin toughening agent designed for the preparation of a tetrafunctional epoxy resin. The block structure includes repeating units containing phenolic hydroxyl groups and repeating units without phenolic hydroxyl groups, and the phenolic hydroxyl groups participate in the crosslinking reaction of the epoxy resin, thereby introducing the thermoplastic polyimide resin toughening agent into the epoxy resin system. Patent CN 118307780 discloses a thermoplastic polyimide resin toughening agent containing isocyanate crosslinking groups to improve the toughness of bismaleimide resin.

[0004] Due to limitations in end-group reactivity and molecular structure heat resistance, the aforementioned toughening agents for thermoplastic polyimide resins with characteristic groups cannot meet the toughening requirements of thermosetting polyimide resins with glass transition temperatures above 300°C. Therefore, in order to achieve high-temperature toughening of thermosetting polyimide resins, it is necessary to develop a thermoplastic polyimide resin toughening agent that combines toughness, heat resistance, and system compatibility. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] The technical problem to be solved by the present invention is that existing thermoplastic polyimide resin toughening agents are mainly developed for thermosetting resins with low temperature resistance, such as epoxy and bismaleimide resins. The molecular structure of the toughening agents is difficult to meet the toughening requirements of thermosetting polyimide resins with glass transition temperatures above 300°C.

[0007] (II) Technical Solution

[0008] To address the aforementioned technical problems, this invention provides a thermoplastic polyimide resin toughening agent with both affinity and repulsion properties. The polyimide resin toughening agent is a copolymeric thermoplastic polyimide polymer composed of a rigid segment A and a flexible segment B, with the following structural formula:

[0009]

[0010] The rigid chain segment A includes the structure shown in Formula I:

[0011]

[0012] The flexible chain segment B includes the structure shown in Formula II:

[0013]

[0014] In Formula I, Ar1 represents any of the following substituents:

[0015]

[0016] In Formula I, Ar2 represents any of the following substituents:

[0017]

[0018]

[0019] Where m is any integer from 3 to 300, and n is any integer from 3 to 300.

[0020] The rigid segment A is provided by a polyamic acid solution A', and the polyamic acid solution A' is prepared by:

[0021] S1.1 Dissolve 4,4'-diaminodiphenyl ether in an aprotic polar solvent and heat to obtain diamine solution A';

[0022] S1.2 Dissolve pyromellitic dianhydride in an organic solvent, heat and stir until the pyromellitic dianhydride is completely dissolved to obtain dianhydride solution A';

[0023] S1.3 Add the dianhydride solution A' to the diamine solution A', stir and heat to carry out the polymerization reaction, and obtain polyamic acid solution A'.

[0024] In a preferred embodiment of the present invention, in step S1.1, the heating temperature is 40℃-100℃, and the concentration of the obtained diamine solution A' is 20wt%-80wt%.

[0025] In a preferred embodiment of the present invention, in step S1.2, the heating temperature of the heating and stirring is 40°C-80°C, and the concentration of the obtained dianhydride solution A' is 20wt%-80wt%.

[0026] In a preferred embodiment of the present invention, in step S1.3, the heating temperature is 60℃-100℃, and the reaction time of the polymerization reaction is 1h-6h.

[0027] In a preferred embodiment of the present invention, the rigid segment A is synthesized from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether, wherein the monomer molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is (0.95-1.05):(0.95-1.05).

[0028] The rigid segment B is provided by a polyamic acid solution B', and the polyamic acid solution B' is prepared by:

[0029] S2.1 Dissolve an aromatic diamine in an aprotic polar solvent and heat to obtain a diamine solution B';

[0030] S2.2 Dissolve aromatic dianhydride in an organic solvent, heat and stir until the aromatic dianhydride is completely dissolved to obtain dianhydride solution B';

[0031] S2.3 Add the dianhydride solution B' to the diamine solution B', stir and heat to carry out the polymerization reaction, and obtain polyamic acid solution B'.

[0032] In a preferred embodiment of the present invention, in step S2.1, the heating temperature is 40°C-100°C, and the concentration of the obtained diamine solution B' is 20wt%-80wt%.

[0033] In a preferred embodiment of the present invention, in step S2.2, the heating temperature of the heating and stirring is 40°C-80°C, and the concentration of the obtained dianhydride solution B' is 20wt%-80wt%.

[0034] In a preferred embodiment of the present invention, in step S2.3, the heating temperature is 60℃-100℃, and the reaction time of the polymerization reaction is 1h-6h.

[0035] In a preferred embodiment of the present invention, the monomer molar ratio of the aromatic dianhydride to the aromatic diamine is (0.95-1.05):(0.95-1.05).

[0036] In a preferred embodiment of the present invention, the monomer of the aromatic dianhydride is selected from one or more of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride.

[0037] In a preferred embodiment of the present invention, the monomer of the aromatic diamine is selected from one or more of the following: m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenyl sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0038] In a preferred embodiment of the present invention, the aprotic polar solvent is selected from one or more of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0039] In a preferred embodiment of the present invention, the organic solvent is selected from one or a mixture of several of the following in any proportion: alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0040] This invention also provides a method for preparing a biocompatible thermoplastic polyimide resin toughening agent, comprising the following steps:

[0041] S1. Add polyamic acid solution B' to polyamic acid solution A', stir the solution and heat it to 150℃-200℃, react under vacuum for 1h-12h, and obtain a thermoplastic polyimide resin toughening agent with both affinity and hydrophobicity.

[0042] S2. The thermoplastic polyimide resin toughening agent with both affinity and non-affinity properties is mechanically pulverized to obtain thermoplastic polyimide resin toughening agent powder with both affinity and non-affinity properties.

[0043] This invention also provides an application of a biocompatible thermoplastic polyimide resin toughening agent in the toughening and modification of thermosetting polyimide resins.

[0044] (III) Beneficial Effects

[0045] The above-described technical solution of the present invention has the following advantages:

[0046] The biocompatibility-repellency integrated thermoplastic polyimide resin toughening agent of the present invention is a copolymerized thermoplastic polyimide resin composed of rigid segment A and flexible segment B. The rigid segment A has a regular molecular structure and is insoluble in thermosetting polyimide resin, while the flexible segment B has a flexible structure and is soluble in thermosetting polyimide resin, thus achieving a biocompatibility-repellency integrated design for the thermoplastic polyimide resin toughening agent. The rigid segment A and flexible segment B undergo a copolymerization reaction in the form of a polyamic acid solution, followed by high-temperature imidization to obtain the thermoplastic polyimide resin toughening agent.

[0047] This invention discloses a thermoplastic polyimide resin toughening agent with both affinity and repulsion properties, synthesized from aromatic monomers. Through the control of the rigidity and flexibility of the molecular backbone, it achieves excellent toughness while ensuring the toughening agent's heat resistance. This agent is suitable for toughening thermosetting polyimide resin matrices. When this thermoplastic polyimide resin toughening agent modifies a thermosetting polyimide resin matrix, the rigid structure is immiscible with the matrix, while the flexible structure is miscible. The toughening agent can maintain its original morphology within the matrix and exert its toughening effect. Detailed Implementation

[0048] 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.

[0049] This invention provides a thermoplastic polyimide resin toughening agent with both affinity and repulsion properties. The polyimide resin toughening agent is a copolymeric thermoplastic polyimide polymer composed of rigid segment A and flexible segment B, with the following structural formula:

[0050]

[0051] The rigid chain segment A includes the structure shown in Formula I:

[0052]

[0053] The flexible chain segment B includes the structure shown in Formula II:

[0054]

[0055] In Formula I, Ar1 represents any of the following substituents:

[0056]

[0057] In Formula I, Ar2 represents any of the following substituents:

[0058]

[0059] Where m is any integer from 3 to 300, and n is any integer from 3 to 300.

[0060] The present invention also provides a method for preparing a polyamic acid solution A', wherein the rigid segment A is provided, comprising the steps of:

[0061] S1.1 Dissolve 4,4'-diaminodiphenyl ether in an aprotic polar solvent in a dry reaction vessel and heat under inert gas protection to obtain diamine solution A';

[0062] S1.2 Dissolve pyromellitic dianhydride in an organic solvent in a dry reaction vessel, heat and stir until the pyromellitic dianhydride is completely dissolved to obtain dianhydride solution A';

[0063] S1.3 Add the dianhydride solution A' to the diamine solution A', stir and heat to carry out the polymerization reaction, and obtain polyamic acid solution A'.

[0064] In a preferred embodiment of the present invention, in step S1.1, the heating temperature is 40℃-100℃, and the concentration of the obtained diamine solution A' is 20wt%-80wt%.

[0065] In a preferred embodiment of the present invention, in step S1.2, the heating temperature of the heating and stirring is 40°C-80°C, and the concentration of the obtained dianhydride solution A' is 20wt%-80wt%.

[0066] In a preferred embodiment of the present invention, in step S1.3, the heating temperature is 60℃-100℃, and the reaction time of the polymerization reaction is 1h-6h.

[0067] In a preferred embodiment of the present invention, the rigid segment A is synthesized from pyromellitic dianhydride and 4,4'-diaminodiphenyl ether, wherein the monomer molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is (0.95-1.05):(0.95-1.05).

[0068] The present invention also provides a method for preparing a polyamic acid solution B', wherein the rigid segment B is provided, comprising the steps of:

[0069] S2.1 Dissolve an aromatic diamine in an aprotic polar solvent in a dry reaction vessel and heat under inert gas protection to obtain a diamine solution B';

[0070] S2.2 Dissolve the aromatic dianhydride in an organic solvent in a dry reaction vessel, heat and stir until the aromatic dianhydride is completely dissolved to obtain dianhydride solution B';

[0071] S2.3 Add the dianhydride solution B' to the diamine solution B', stir and heat to carry out the polymerization reaction, and obtain polyamic acid solution B'.

[0072] In a preferred embodiment of the present invention, in step S2.1, the heating temperature is 40°C-100°C, and the concentration of the obtained diamine solution B' is 20wt%-80wt%.

[0073] In a preferred embodiment of the present invention, in step S2.2, the heating temperature of the heating and stirring is 40°C-80°C, and the concentration of the obtained dianhydride solution B' is 20wt%-80wt%.

[0074] In a preferred embodiment of the present invention, in step S2.3, the heating temperature is 60℃-100℃, and the reaction time of the polymerization reaction is 1h-6h.

[0075] In a preferred embodiment of the present invention, the monomer molar ratio of the aromatic dianhydride to the aromatic diamine is (0.95-1.05):(0.95-1.05).

[0076] In a preferred embodiment of the present invention, the monomer of the aromatic dianhydride is selected from one or more of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride.

[0077] In a preferred embodiment of the present invention, the monomer of the aromatic diamine is selected from one or more of the following: m-phenylenediamine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenyl sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

[0078] In a preferred embodiment of the present invention, the aprotic polar solvent is selected from one or more of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0079] In a preferred embodiment of the present invention, the organic solvent is selected from one or a mixture of several of the following in any proportion: alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0080] This invention also provides a method for preparing a biocompatible thermoplastic polyimide resin toughening agent, comprising the following steps:

[0081] S1. Add polyamic acid solution B' to polyamic acid solution A', stir the solution and heat it to 150℃-200℃ for 1h-12h, evacuate the reaction vessel to a vacuum degree ≤-0.095MPa, and cool and separate the volatile solvent during the reaction. After cooling, obtain the thermoplastic polyimide resin toughening agent with both affinity and hydrophobicity.

[0082] S2. The thermoplastic polyimide resin toughening agent with both affinity and non-affinity properties is mechanically pulverized to obtain thermoplastic polyimide resin toughening agent powder with both affinity and non-affinity properties.

[0083] This invention raises the glass transition temperature of the thermoplastic polyimide resin toughening agent to above 250°C. Simultaneously, the toughening agent possesses a unique molecular structure characterized by both affinity and hydrophobicity; that is, the flexible portion of the toughening agent's molecular chain is soluble and similar in structure to the thermosetting polyimide resin, while the rigid portion is insoluble. When the thermoplastic polyimide resin toughening agent is mixed with the thermosetting polyimide resin at high temperatures, it can partially retain the particle morphology of the thermoplastic resin, achieving a synergistic toughening effect between soluble and insoluble components, thereby enabling high-temperature toughening of the thermosetting polyimide resin.

[0084] Example 1

[0085] This embodiment provides a method for preparing a biocompatible thermoplastic polyimide resin toughening agent, including the following steps:

[0086] S1.1 Dissolve 200.24 g of 4,4'-diaminodiphenyl ether in 467.23 g of dioxane solvent in a dry reaction vessel, and heat to 80 °C under inert gas protection to obtain a 30 wt% diamine solution A'.

[0087] S1.2 Dissolve 218.12 g of pyromellitic dianhydride in 508.95 g of N,N-dimethylacetamide solvent in a dry reaction vessel, and heat to 80 °C until the monomer is completely dissolved to obtain a dianhydride solution A' with a concentration of 30 wt%.

[0088] S1.3 Add the above dianhydride solution A' to the diamine solution A', stir and heat to 85°C for 6 hours to obtain polyamic acid solution A'.

[0089] S2.1 Dissolve 200.24 g of 3,4'-diaminodiphenyl ether in 467.23 g of dioxane solvent in a dry reaction vessel, and heat to 80 °C under inert gas protection to obtain a 30 wt% diamine solution B'.

[0090] S2.2 Dissolve 322.23 g of 3,3',4,4'-benzophenone tetracarboxylic dianhydride in 751.87 g of N,N-dimethylacetamide solvent in a dry reaction vessel, and heat to 80 °C until the monomer is completely dissolved to obtain a dianhydride solution B' with a concentration of 30 wt%.

[0091] S2.3 Add the above dianhydride solution B' to the diamine solution B', stir and heat to 85°C for 6 hours to obtain polyamic acid solution B'.

[0092] S3.1 Add polyamic acid solution B' to polyamic acid solution A', further heat to 180℃ and react for 6 hours. Vacuum the reaction vessel to a vacuum degree of -0.1MPa. During the reaction, the volatile solvent is cooled and separated. After cooling, thermoplastic polyimide resin is obtained.

[0093] S3.2 The resin obtained above is mechanically pulverized to obtain a thermoplastic polyimide resin toughening agent powder with both affinity and hydrophobicity, denoted as TO-1.

[0094] The TO-1 thermoplastic polyimide resin toughening agent prepared in this embodiment was used to toughen and modify thermosetting polyimide resin at a rate of 10 wt%. The untoughened thermosetting polyimide resin had a simply supported beam impact strength of 15.3 kJ / m. 2 The impact strength of the simply supported beam of the toughened thermosetting polyimide resin increased to 21.7 kJ / m. 2 .

[0095] Example 2

[0096] This embodiment provides a method for preparing a biocompatible thermoplastic polyimide resin toughening agent, including the following steps:

[0097] S1.1 Dissolve 200.24 g of 4,4'-diaminodiphenyl ether in 467.23 g of dioxane solvent in a dry reaction vessel, and heat to 80 °C under inert gas protection to obtain a 30 wt% diamine solution A'.

[0098] S1.2 Dissolve 218.12 g of pyromellitic dianhydride in 508.95 g of N,N-dimethylacetamide solvent in a dry reaction vessel, and heat to 80 °C until the monomer is completely dissolved to obtain a dianhydride solution A' with a concentration of 30 wt%.

[0099] S1.3 Add the above dianhydride solution A' to the diamine solution A', stir and heat to 85°C for 6 hours to obtain polyamic acid solution A'.

[0100] S2.1 Dissolve 348.44 g of 9,9-bis(4-aminophenyl)fluorene in 813.03 g of dioxane solvent in a dry reaction vessel, and heat to 85 °C under inert gas protection to obtain a 30 wt% diamine solution B'.

[0101] S2.2 Dissolve 310.21 g of 4,4'-oxobisphthalic anhydride in 723.82 g of N-methylpyrrolidone solvent in a dry reaction vessel, and heat to 80 °C until the monomer is completely dissolved to obtain a dianhydride solution B' with a concentration of 30 wt%.

[0102] S2.3 Add the above dianhydride solution B' to the diamine solution B', stir and heat to 85℃ for polymerization reaction for 5 hours to obtain polyamic acid solution B'.

[0103] S3.1 Add polyamic acid solution B' to polyamic acid solution A', further heat to 180℃ and react for 8 hours. Vacuum the reaction vessel to a vacuum degree of -0.1MPa. During the reaction, the volatile solvent is cooled and separated. After cooling, thermoplastic polyimide resin is obtained.

[0104] S3.2 The resin obtained above is mechanically pulverized to obtain a thermoplastic polyimide resin toughening agent powder with both affinity and hydrophobicity, denoted as OF-1.

[0105] The OF-1 thermoplastic polyimide resin toughening agent prepared in this embodiment was used to toughen and modify thermosetting polyimide resin at a rate of 10 wt%. The impact strength of the untoughened thermosetting polyimide resin in a simply supported beam was 15.3 kJ / m. 2 The impact strength of the simply supported beam of the toughened thermosetting polyimide resin increased to 27.4 kJ / m. 2 .

[0106] Example 3

[0107] This embodiment provides a method for preparing a biocompatible thermoplastic polyimide resin toughening agent, including the following steps:

[0108] S1.1 Dissolve 200.24 g of 4,4'-diaminodiphenyl ether in 467.23 g of dioxane solvent in a dry reaction vessel, and heat to 80 °C under inert gas protection to obtain a 30 wt% diamine solution A'.

[0109] S1.2 Dissolve 218.12 g of pyromellitic dianhydride in 508.95 g of N,N-dimethylacetamide solvent in a dry reaction vessel, and heat to 80 °C until the monomer is completely dissolved to obtain a dianhydride solution A' with a concentration of 30 wt%.

[0110] S1.3 Add the above dianhydride solution A' to the diamine solution A', stir and heat to 85°C for 6 hours to obtain polyamic acid solution A'.

[0111] S2.1 Dissolve 292.33 g of 1,3-bis(4'-aminophenoxy)benzene in 682.10 g of tetrahydrofuran solvent in a dry reaction vessel, and heat to 60 °C under inert gas protection to obtain a 30 wt% diamine solution B'.

[0112] S2.2 Dissolve 294.22 g of 2,3,3',4'-biphenyltetracarboxylic dianhydride in 686.51 g of ethanol solvent in a dry reaction vessel, and heat to 75 °C until the monomer is completely dissolved to obtain a dianhydride solution B' with a concentration of 30 wt%.

[0113] S2.3 Add the above dianhydride solution B to the diamine solution B', stir and heat to 78°C for 6 hours to obtain polyamic acid solution B'.

[0114] S3.1 Add polyamic acid solution B' to polyamic acid solution A', further heat to 180℃ and react for 8 hours. Vacuum the reaction vessel to a vacuum degree of -0.1MPa. During the reaction, the volatile solvent is cooled and separated. After cooling, thermoplastic polyimide resin is obtained.

[0115] S3.2 The resin obtained above is mechanically pulverized to obtain thermoplastic polyimide resin toughening agent powder, denoted as PA-1.

[0116] The PA-1 thermoplastic polyimide resin toughening agent prepared in this embodiment was used to toughen and modify thermosetting polyimide resin at a rate of 10 wt%. The untoughened thermosetting polyimide resin had a simply supported beam impact strength of 15.3 kJ / m. 2 The impact strength of the simply supported beam of the toughened thermosetting polyimide resin increased to 32.8 kJ / m. 2 .

[0117] The molar ratio of aromatic diamine and aromatic dianhydride in Example 3 was adjusted from 1.00:1.00 to 1.00:0.99, 1.00:0.97, and 1.00:0.95, respectively. Using the same preparation method as in Example 3, thermoplastic polyimide toughening agents PA-2, PA-3, and PA-4 with different molecular weights were obtained.

[0118] The prepared thermoplastic polyimide resin toughening agent was used to toughen and modify thermosetting polyimide resin at a dosage of 10 wt%. The impact strength of the untoughened thermosetting polyimide resin in a simply supported beam was 15.3 kJ / m. 2 The impact strength of simply supported beams of thermosetting polyimide resin toughened with PA-2, PA-3, and PA-4 toughening agents was increased to 28.6 kJ / m. 2 25.5kJ / m 2 21.9kJ / m 2 .

[0119] The preparation method of this invention can effectively control the molecular structure and molecular weight of the obtained thermoplastic polyimide resin toughening agent, realize the soluble-insoluble synergistic toughening of thermoplastic toughening agent with a hydrophilic-reactive structure in thermosetting polyimide resin, thereby improving the impact toughness of thermosetting polyimide resin, which is conducive to the further promotion and application of thermosetting polyimide resin.

[0120] It should be noted 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 mutually. Each embodiment focuses on describing the differences from other embodiments. For the embodiments of the method, relevant parts can be referred to the description of the device embodiments (as appropriate). The present invention is not limited to the specific steps and structures described above. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0121] 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 thermoplastic polyimide resin toughening agent with both affinity and repulsion properties, characterized in that, The polyimide resin toughening agent is a copolymeric thermoplastic polyimide polymer composed of rigid segment A and flexible segment B, with the following structural formula: The rigid chain segment A has the structure shown in Equation I: Formula I The flexible chain segment B has the structure shown in Formula II: Formula II In Formula I, Ar1 represents any of the following substituents: 、 、 、 、 ； In Formula I, Ar2 represents any of the following substituents: 、 、 、 、 、 、 、 、 ； Where m is any integer from 3 to 300, and n is any integer from 3 to 300; The rigid segment A is provided by polyamic acid solution B', and the flexible segment B is provided by polyamic acid solution A'; The method for preparing the polyamic acid solution A' is as follows: S1.1 Dissolve 4,4'-diaminodiphenyl ether in an aprotic polar solvent and heat to obtain diamine solution A'; S1.2 Dissolve pyromellitic dianhydride in an organic solvent, heat and stir until the pyromellitic dianhydride is completely dissolved to obtain dianhydride solution A'; S1.3 Add the dianhydride solution A' to the diamine solution A', stir and heat to carry out the polymerization reaction to obtain polyamic acid solution A'; The preparation method of the polyamic acid solution B' is as follows: S2.1 Dissolve an aromatic diamine in an aprotic polar solvent and heat to obtain a diamine solution B'; S2.2 Dissolve aromatic dianhydride in an organic solvent, heat and stir until the aromatic dianhydride is completely dissolved to obtain dianhydride solution B'; S2.3 Add the dianhydride solution B' to the diamine solution B', stir and heat to carry out the polymerization reaction to obtain polyamic acid solution B'; The biocompatibility-repellency integrated thermoplastic polyimide resin toughening agent is prepared through the following steps: S1. Add polyamic acid solution B' to polyamic acid solution A', stir the solution and heat it to 150℃-200℃, react under vacuum for 1h-12h, and obtain a thermoplastic polyimide resin toughening agent with both affinity and hydrophobicity. S2. The thermoplastic polyimide resin toughening agent with both affinity and non-affinity properties is mechanically pulverized to obtain thermoplastic polyimide resin toughening agent powder with both affinity and non-affinity properties.

2. The polyimide resin toughening agent as described in claim 1, characterized in that, In step S1.1, the heating temperature is 40℃-100℃, and the concentration of the obtained diamine solution A' is 20wt%-80wt%. In step S1.2, the heating temperature for heating and stirring is 40℃-80℃, and the concentration of the obtained dianhydride solution A' is 20wt%-80wt%. In step S1.3, the heating temperature is 60℃-100℃, and the polymerization reaction time is 1h-6h.

3. The polyimide resin toughening agent as described in claim 1, characterized in that, The monomer molar ratio of the pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is (0.95-1.05):(0.95-1.05).

4. The polyimide resin toughening agent as described in claim 1, characterized in that, In step S2.1, the heating temperature is 40℃-100℃, and the concentration of the obtained diamine solution B' is 20wt%-80wt%. In step S2.2, the heating temperature for heating and stirring is 40℃-80℃, and the concentration of the obtained dianhydride solution B' is 20wt%-80wt%. In step S2.3, the heating temperature is 60℃-100℃, and the polymerization reaction time is 1h-6h.

5. The polyimide resin toughening agent as described in claim 1, characterized in that, The monomer molar ratio of the aromatic dianhydride to the aromatic diamine is (0.95-1.05):(0.95-1.05). The monomer of the aromatic dianhydride is selected from one or more of 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride. The monomer of the aromatic diamine is selected from one or more of the following: m-phenylenediamine, 3,4'-diaminodiphenyl ether, 2,2-(4-aminophenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 1,3-bis(4'-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminodiphenylmethane, 4,4'-diaminophenyl sulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

6. The polyimide resin toughening agent as described in claim 1, characterized in that, The aprotic polar solvent is selected from one or more of tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone. The organic solvent is selected from one or a mixture of several of the following in any proportion: alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone.

7. The application of the thermoplastic polyimide resin toughening agent according to any one of claims 1-6 in the toughening modification of thermosetting polyimide resins.

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