Hydrophilic-hydrophobic thermoplastic polyimide resin flexibilizer and preparation method thereof

Abstract

The invention belongs to the technical field of high polymer material preparation, and relates to a hydrophilic-hydrophobic thermoplastic polyimide resin flexibilizer and a preparation method thereof. The glass transition temperature of the thermoplastic polyimide resin flexibilizer is increased to 250 DEG C or above, and meanwhile, the flexibilizer has the hydrophilic and hydrophobic integrated molecular structure characteristic, that is, the flexible part of a molecular chain of the flexibilizer is similar to the molecular structure of thermosetting polyimide resin and is soluble, and the rigid part of the molecular chain of the flexibilizer is insoluble with the thermoplastic polyimide resin. After the thermoplastic polyimide resin flexibilizer and the thermosetting polyimide resin are mixed at a high temperature, the particle morphology of the thermoplastic resin can be partially reserved, so that the purpose of soluble-insoluble synergistic toughening is achieved, and the high-temperature-resistant toughening of the thermosetting polyimide resin is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material preparation, and relates to a thermoplastic polyimide resin toughening agent with affinity and hydrophobicity and a preparation method thereof. Background Art

[0002] At present, the toughening methods of thermosetting polyimide resin mainly include resin main chain molecular structure design, inorganic powder blending toughening and thermoplastic resin toughening. Specifically, the main chain molecular structure design refers to the introduction of flexible molecular long chains containing ether bonds, sulfone groups, etc. into the molecular structure of thermosetting polyimide during the resin synthesis process to increase the flexibility of the molecular main chain to improve the toughness of the resin. However, for the material research and development process, this process usually requires repeated trial and error, a long cycle and high cost. Adding inorganic powders such as SiO2 to thermosetting polyimide resin can also improve the brittleness of the resin to a certain extent, and can serve as an anchoring site for the resin matrix under a destructive load to play a toughening role. However, the resin and the inorganic powder only have a weak physical connection through resin infiltration. At the same time, the inorganic powder is very easy to agglomerate and requires further surface treatment before it can be used as a toughening component. The efficiency is low and it is 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, the long-term operating temperature of thermoplastic polyimide resin is higher than 200°C. Therefore, 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, a thermoplastic polyimide resin toughener with toughness, heat resistance and system compatibility should be selected as a toughening component. For this purpose, it is necessary to design a thermoplastic polyimide resin toughener for a specific thermosetting resin molecular structure to ensure the compatibility between the thermosetting resin and the thermoplastic toughener to achieve the best toughening effect. For example, in the patent CN 113861421, a block-type thermoplastic polyimide resin toughener is designed for the preparation of a tetrafunctional epoxy resin. The block structure contains repeating units containing phenolic hydroxyl groups and repeating units without phenolic hydroxyl groups, and the phenolic hydroxyl groups participate in the cross-linking reaction of the epoxy resin, thereby introducing the thermoplastic polyimide resin toughener into the epoxy resin system. In the patent CN 118307780, a thermoplastic polyimide resin toughener containing an isocyanate cross-linking group is prepared to improve the toughness of bismaleimide resin.

[0004] Due to the end group reactivity and molecular structure heat resistance limitations, the thermoplastic polyimide resin toughening agent with the above characteristic groups cannot meet the toughening requirements of thermosetting polyimide resins with a glass transition temperature 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] 1. Technical issues to be resolved

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

[0007] (II) Technical solution

[0008] In order to solve the above technical problems, the present invention provides a thermoplastic polyimide resin toughening agent with affinity and hydrophobicity. The polyimide resin toughening agent is a copolymerized thermoplastic polyimide polymer, which is composed of a rigid segment A and a flexible segment B, and has the following structural formula:

[0009]

[0010] The rigid segment A comprises a structure shown in formula I:

[0011]

[0012] The flexible segment B comprises a structure shown in Formula II:

[0013]

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

[0015]

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

[0017]

[0018]

[0019] Here, 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 preparation method of the polyamic acid solution A' is as follows:

[0021] S1.1 dissolving 4,4'-diaminodiphenyl ether in a non-protonic polar solvent and heating to obtain a diamine solution A';

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

[0023] S1.3 adding the dianhydride solution A' into the diamine solution A', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution A'.

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

[0025] As 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 20 wt %-80 wt %.

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

[0027] As a preferred embodiment of the present invention, the rigid segment A is synthesized from pyromellitic anhydride and 4,4'-diaminodiphenyl ether, and the monomer molar ratio of pyromellitic anhydride 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 preparation method of the polyamic acid solution B' is:

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

[0030] S2.2 dissolving the aromatic dianhydride in an organic solvent, heating and stirring until the aromatic dianhydride is completely dissolved, to obtain a dianhydride solution B';

[0031] S2.3 adding the dianhydride solution B' into the diamine solution B', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution B'.

[0032] As 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 20 wt %-80 wt %.

[0033] As 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 20 wt %-80 wt %.

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

[0035] As 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] As 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'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and 4,4'-hexafluoroisopropylphthalic anhydride.

[0037] As a preferred embodiment of the present invention, the monomer of the aromatic diamine is selected from one or more of 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] As 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] As a preferred embodiment of the present invention, the organic solvent is selected from one of alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone or a mixture of any proportion of the above.

[0040] The present invention also provides a method for preparing a hydrophilic-hydrophobic thermoplastic polyimide resin toughening agent, comprising the steps of:

[0041] S1. Adding the polyamic acid solution B' to the polyamic acid solution A', stirring the solution and heating it to 150 ℃-200 ℃, reacting in vacuum for 1h-12h, and cooling to obtain a thermoplastic polyimide resin toughening agent having affinity and phobia;

[0042] S2. Mechanically crushing the hydrophobic thermoplastic polyimide resin toughening agent to obtain hydrophobic thermoplastic polyimide resin toughening agent powder.

[0043] The present invention also provides an application of a hydrophilic-intergrated thermoplastic polyimide resin toughening agent in toughening and modifying thermosetting polyimide resin.

[0044] (III) Beneficial effects

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

[0046] The hydrophilic-integrated thermoplastic polyimide resin toughener of the present invention is a copolymerized thermoplastic polyimide resin composed of a rigid segment A and a flexible segment B, wherein the rigid segment A has a regular molecular structure and is insoluble in the thermosetting polyimide resin, and the flexible segment B has a compliant structure and is soluble in the thermosetting polyimide resin, thereby realizing the hydrophilic-integrated design of the thermoplastic polyimide resin toughener. The rigid segment A and the flexible segment B undergo copolymerization in the form of a polyamic acid solution, and the thermoplastic polyimide resin toughener is obtained after high-temperature imidization.

[0047] The hydrophilic-integrated thermoplastic polyimide resin toughening agent of the present invention is synthesized from aromatic monomers and regulated by the rigidity and flexibility of the molecular main chain, so that a resin toughening agent with excellent toughness can be obtained under the premise of ensuring the heat resistance of the toughening agent, and is suitable for toughening the matrix of thermosetting polyimide resin. When the hydrophilic-integrated thermoplastic polyimide resin toughening agent modifies the thermosetting polyimide resin matrix, the rigid structure is immiscible with the matrix, and the flexible structure is miscible with the matrix, and the toughening agent can maintain its original morphology in the matrix and exert a toughening effect. DETAILED DESCRIPTION

[0048] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0049] The present invention provides a thermoplastic polyimide resin toughening agent with affinity and hydrophobicity. The polyimide resin toughening agent is a copolymerized thermoplastic polyimide polymer, which is composed of a rigid segment A and a flexible segment B, and has the following structural formula:

[0050]

[0051] The rigid segment A comprises a structure shown in Formula I:

[0052]

[0053] The flexible segment B comprises a structure shown in Formula II:

[0054]

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

[0056]

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

[0058]

[0059] Here, 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', providing the rigid segment A, comprising the steps of:

[0061] S1.1 dissolving 4,4'-diaminodiphenyl ether in a non-protonic polar solvent in a dry reaction vessel, and heating under the protection of an inert gas to obtain a diamine solution A';

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

[0063] S1.3 adding the dianhydride solution A' into the diamine solution A', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution A'.

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

[0065] As 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 20 wt %-80 wt %.

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

[0067] As a preferred embodiment of the present invention, the rigid segment A is synthesized from pyromellitic anhydride and 4,4'-diaminodiphenyl ether, and the monomer molar ratio of pyromellitic anhydride 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', providing the rigid segment B, comprising the steps of:

[0069] S2.1 dissolving an aromatic diamine in a non-protonic polar solvent in a dry reaction vessel, and heating under the protection of an inert gas to obtain a diamine solution B';

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

[0071] S2.3 adding the dianhydride solution B' into the diamine solution B', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution B'.

[0072] As 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 20 wt %-80 wt %.

[0073] As 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 20 wt %-80 wt %.

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

[0075] As 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] As 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'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride and 4,4'-hexafluoroisopropylphthalic anhydride.

[0077] As a preferred embodiment of the present invention, the monomer of the aromatic diamine is selected from one or more of 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] As 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] As a preferred embodiment of the present invention, the organic solvent is selected from one of alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone or a mixture of any proportion of the above.

[0080] The present invention also provides a method for preparing a thermoplastic polyimide resin toughening agent having affinity and hydrophobicity, comprising the steps of:

[0081] S1. Adding the polyamic acid solution B' to the polyamic acid solution A', stirring the solution and heating it to 150°C-200°C for 1h-12h, evacuating the reaction vessel to a vacuum degree of ≤-0.095MPa, cooling and separating the volatile solvent during the reaction, and obtaining a thermoplastic polyimide resin toughening agent having affinity and repellency after cooling;

[0082] S2. Mechanically crushing the hydrophobic thermoplastic polyimide resin toughening agent to obtain hydrophobic thermoplastic polyimide resin toughening agent powder.

[0083] The present invention increases the glass transition temperature of the thermoplastic polyimide resin toughening agent to above 250°C, and the toughening agent has a molecular structure characteristic of being both affinity and repellency, that is, the flexible part of the toughening agent molecular chain is similar to the molecular structure of the thermosetting polyimide resin and is soluble, 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 morphology of the thermoplastic resin particles can be partially retained to achieve the purpose of soluble-insoluble synergistic toughening, thereby realizing the high temperature resistant toughening of the thermosetting polyimide resin.

[0084] Example 1

[0085] This embodiment provides a method for preparing a thermoplastic polyimide resin toughening agent having affinity and hydrophobicity, comprising the steps of:

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

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

[0088] S1.3 Add the above dianhydride solution A' into the diamine solution A', stir and heat to 85°C for polymerization reaction for 6 hours to obtain a 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 container, and heat to 80° C. under the protection of an inert gas to obtain a diamine solution B' with a concentration of 30 wt%.

[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, heat to 80° C. until the monomer is completely dissolved, and obtain a dianhydride solution B' with a concentration of 30 wt%.

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

[0092] S3.1 Add polyamic acid solution B' into polyamic acid solution A', further heat to 180°C for reaction for 6h, evacuate the reaction vessel to a vacuum degree of -0.1MPa, cool and separate the volatile solvent during the reaction, and obtain thermoplastic polyimide resin after cooling.

[0093] S3.2 The resin obtained above is mechanically crushed to obtain a thermoplastic polyimide resin toughening agent powder having affinity and hydrophobicity, which is recorded as TO-1.

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

[0095] Example 2

[0096] This embodiment provides a method for preparing a thermoplastic polyimide resin toughening agent having affinity and hydrophobicity, comprising the steps of:

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

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

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

[0100] S2.1 348.44 g of 9,9-bis(4-aminophenyl)fluorene was dissolved in 813.03 g of dioxane solvent in a dry reaction container, and heated to 85° C. under the protection of an inert gas to obtain a diamine solution B′ with a concentration of 30 wt %.

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

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

[0103] S3.1 Add polyamic acid solution B' into polyamic acid solution A', further heat to 180°C for reaction for 8h, evacuate the reaction vessel to a vacuum degree of -0.1MPa, cool and separate the volatile solvent during the reaction, and obtain thermoplastic polyimide resin after cooling.

[0104] S3.2 The resin obtained above is mechanically crushed to obtain a thermoplastic polyimide resin toughening agent powder having affinity and hydrophobicity, which is recorded as OF-1.

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

[0106] Example 3

[0107] This embodiment provides a method for preparing a thermoplastic polyimide resin toughening agent having affinity and hydrophobicity, comprising the steps of:

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

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

[0110] S1.3 Add the above dianhydride solution A' into the diamine solution A', stir and heat to 85°C for polymerization reaction for 6 hours to obtain a 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 container, and heat to 60° C. under inert gas protection to obtain a diamine solution B' with a concentration of 30 wt%.

[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, heat to 75° C. until the monomer is completely dissolved, and 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 polymerization reaction for 6 hours to obtain a polyamic acid solution B'.

[0114] S3.1 Add polyamic acid solution B' into polyamic acid solution A', further heat to 180°C for reaction for 8h, evacuate the reaction vessel to a vacuum degree of -0.1MPa, cool and separate the volatile solvent during the reaction, and obtain thermoplastic polyimide resin after cooling.

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

[0116] The PA-1 thermoplastic polyimide resin toughening agent prepared in this example is used to toughen and modify the thermosetting polyimide resin at a rate of 10 wt%. The simply supported beam impact strength of the untoughened thermosetting polyimide resin is 15.3 kJ / m 2 The toughened thermosetting polyimide resin simply supported beam impact strength is increased to 32.8kJ / 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, and the same preparation method as in Example 3 was used to obtain thermoplastic polyimide toughening agents PA-2, PA-3 and PA-4 with different molecular weights.

[0118] The prepared thermoplastic polyimide resin toughening agent was used to toughen and modify the thermosetting polyimide resin at 10 wt%. The simple supported beam impact strength of the untoughened thermosetting polyimide resin was 15.3 kJ / m 2 The simply supported beam impact strength 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 the present 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 the thermoplastic toughening agent with an affinity-repellency integrated structure in the thermosetting polyimide resin, thereby improving the impact toughness of the thermosetting polyimide resin, which is beneficial to the further promotion and application of the thermosetting polyimide resin.

[0120] 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 specific steps and structures described above. In addition, for the sake of brevity, a detailed description of known method technologies is omitted here.

[0121] 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 thermoplastic polyimide resin toughening agent having affinity and hydrophobicity, characterized in that: The polyimide resin toughening agent is a copolymerized thermoplastic polyimide polymer, which is composed of a rigid segment A and a flexible segment B, and has the following structural formula: The rigid segment A comprises a structure shown in formula I: The flexible segment B comprises a structure shown in Formula II: In formula I, Ar1 represents any one of the following substituents: In formula I, Ar2 represents any one of the following substituents: Here, m is any integer from 3 to 300, and n is any integer from 3 to 300.

2. The polyimide resin toughening agent according to claim 1, characterized in that: The rigid segment A is provided by a polyamic acid solution A', and the preparation method of the polyamic acid solution A' is as follows: S1.1 dissolving 4,4'-diaminodiphenyl ether in a non-protonic polar solvent and heating to obtain a diamine solution A'; S1.2 Dissolve pyromellitic anhydride in an organic solvent, heat and stir until the pyromellitic anhydride is completely dissolved to obtain a dianhydride solution A'; S1.3 adding the dianhydride solution A' into the diamine solution A', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution A'.

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

4. The polyimide resin toughening agent according to claim 2 or 3, characterized in that: The rigid segment A is synthesized from pyromellitic anhydride and 4,4'-diaminodiphenyl ether, and the monomer molar ratio of pyromellitic anhydride to 4,4'-diaminodiphenyl ether is (0.95-1.05): (0.95-1.05).

5. The polyimide resin toughening agent according to claim 1, characterized in that: The rigid segment B is provided by a polyamic acid solution B', and the preparation method of the polyamic acid solution B' is: S2.1 dissolving an aromatic diamine in an aprotic polar solvent and heating the solvent to obtain a diamine solution B'; S2.2 dissolving the aromatic dianhydride in an organic solvent, heating and stirring until the aromatic dianhydride is completely dissolved, to obtain a dianhydride solution B'; S2.3 adding the dianhydride solution B' into the diamine solution B', stirring and heating to carry out polymerization reaction, to obtain a polyamic acid solution B'.

6. The polyimide resin toughening agent according to claim 5, characterized in that: In step S2.1, the heating temperature is 40°C-100°C, and the concentration of the obtained diamine solution B' is 20wt%-80wt%; 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%; In step S2.3, the heating temperature is 60°C-100°C, and the reaction time of the polymerization reaction is 1h-6h.

7. The polyimide resin toughening agent according to claim 5 or 6, 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'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and 4,4'-hexafluoroisopropylphthalic anhydride; The monomer of the aromatic diamine is selected from one or more of 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'-diaminophenylsulfone, and 2,2-bis[4-(4-aminophenoxy)phenyl]propane.

8. The polyimide resin toughening agent according to claim 2 or 5, 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 of alcohol solvents, tetrahydrofuran, dioxane, N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, or a mixture of several of the above in any proportion.

9. A method for preparing the hydrophilic-hydrophobic thermoplastic polyimide resin toughening agent according to any one of claims 1 to 8, comprising the steps of: S1. Adding the polyamic acid solution B' to the polyamic acid solution A', stirring the solution and heating it to 150 ℃-200 ℃, reacting in vacuum for 1h-12h, and cooling to obtain a thermoplastic polyimide resin toughening agent having affinity and phobia; S2. Mechanically crushing the hydrophobic thermoplastic polyimide resin toughening agent to obtain hydrophobic thermoplastic polyimide resin toughening agent powder.

10. Use of the hydrophilic-interconnected thermoplastic polyimide resin toughening agent according to any one of claims 1 to 8 in toughening and modifying thermosetting polyimide resin.

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