High-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material as well as preparation method and application thereof

Abstract

The invention discloses a high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material as well as a preparation method and application thereof. According to the invention, the mutual exclusion bottleneck of toughness-strength-modulus of high-strength and high-modulus carbon fibers matched with a resin matrix is solved, liquid crystal epoxy monomers with different functionalities are designed and synthesized, the resin matrix is toughened through a liquid crystal intrinsic microcosmic mesocrystal domain, and the rigid structure of a mesocrystal element and an intermolecular hydrogen bond provided by aryl amide are synergistically enhanced and reinforced, so that the rigidity of the resin matrix is improved. Linear bridging of a bifunctional liquid crystal monomer and branch crosslinking of a tetrafunctional liquid crystal monomer are utilized to regulate and control a topological structure of curing crosslinking, a triple network structure of a liquid crystal ordered region-hydrogen bond association domain-topological crosslinking body is formed, and the toughness, strength and rigidity of a resin matrix are synchronously improved; the performance matching with third-generation high-strength high-modulus high-toughness carbon fibers is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite material, a preparation method thereof, and an application thereof. Background Art

[0002] The third-generation high-strength, high-modulus, and high-toughness carbon fiber has become the core reinforcing body of lightweight structural composite materials in the fields of aerospace, high-end equipment, etc. due to its high tensile strength (≥5.5 GPa), high modulus (≥370 GPa), and excellent elongation at break (≥1.5%).

[0003] However, the comprehensive performance of carbon fiber composite materials not only depends on the fiber itself, but more on the interfacial bonding between the resin matrix and the fiber and the matching of its own mechanical properties. With the high-performance of carbon fibers, the problem of performance imbalance between strength, modulus, and toughness of the epoxy resin matrix has become increasingly prominent: although traditional methods of intermolecular hydrogen bond networks, increasing crosslinking density, and molecular chain rigidity can provide high strength and modulus, their brittle characteristics lead to insufficient toughness of the composite material, making it difficult to meet the performance requirements of high damage tolerance for the third-generation carbon fiber composite materials.

[0004] Therefore, there is an urgent need to develop a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite material. Summary of the Invention

[0005] To solve at least some of the above-mentioned problems in the prior art, the present invention utilizes the orientation rearrangement characteristics of the mesomorphic domain of liquid crystal polymers and the molecular designability of liquid crystal polymers, introduces hydrogen bond sites such as arylamides into rigid mesogenic units to construct a dynamic physical crosslinking network, which can effectively improve its modulus while maintaining the strength of the resin matrix. On this basis, through controllable functionalization (epoxidation, amination, etc.) treatment of the end groups of liquid crystal polymers, bifunctional linear and multifunctional three-dimensional molecular structures are designed to precisely control the topological structure of the ordered orientation polymer network in the resin matrix, and synergistically improve the toughness, strength, and modulus of the epoxy resin matrix. Specifically, the present invention includes the following contents.

[0006] In the first aspect of the present invention, a preparation method of a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite material is provided, which includes the following steps:

[0007] (1) Dissolve the aromatic dianhydride and phenolamine in the first solvent, adjust the pH value to 8 - 11, and react at 100 - 160 °C for 8 - 12 h to obtain a bifunctional liquid crystal intermediate P1. Dissolve the aromatic dianhydride and diamine in the second solvent, and react at 120 - 180 °C for 10 - 16 h to obtain a tetrafunctional liquid crystal intermediate P2. Dissolve the intermediates P1 and P2 in epichlorohydrin respectively, and react at 70 - 90 °C for 24 - 48 h, and continue to react at 30 - 50 °C for 2 - 4 h in the presence of a catalyst and an alkaline solution to obtain a bifunctional liquid crystal epoxy monomer and a tetrafunctional liquid crystal epoxy monomer respectively. The first solvent and the second solvent can be the same or different;

[0008] (2) Mix the glycidyl - type epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent to obtain a high - strength, high - modulus and high - toughness epoxy resin composition;

[0009] (3) Combine and cure the high - strength, high - modulus and high - toughness epoxy resin composition with high - strength, high - modulus and high - toughness carbon fiber to obtain the high - strength, high - modulus and high - toughness epoxy resin - based carbon fiber composite material.

[0010] In some embodiments, for the preparation method of the high - strength, high - modulus and high - toughness epoxy resin - based carbon fiber composite material according to the present invention, in step (1), the molar ratio of the aromatic dianhydride to the phenolamine is 1:(2 - 4); the molar ratio of the aromatic dianhydride to the diamine is 1:(2 - 6); the molar ratio of the intermediate P1 or P2 to epichlorohydrin is 1:(6 - 12); the addition amount of the catalyst is 0.2% - 0.5% of the total mass of the reaction system.

[0011] In some embodiments, for the preparation method of the high - strength, high - modulus and high - toughness epoxy resin - based carbon fiber composite material according to the present invention, in step (2), the mass ratio of the glycidyl - type epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:(10 - 30):(20 - 40):(35 - 45).

[0012] In some embodiments, for the preparation method of the high - strength, high - modulus and high - toughness epoxy resin - based carbon fiber composite material according to the present invention, the aromatic dianhydride includes at least one of pyromellitic dianhydride, naphthalene tetracarboxylic dianhydride and perylene tetracarboxylic dianhydride; the phenolamine includes at least one of p - aminophenol, m - aminophenol, p - hydroxy phenethylamine, 2 - amino - 4 - hydroxybenzamide and N-(4 - aminophenyl)-3 - hydroxybenzamide; the diamine includes at least one of p - phenylenediamine, m - phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide and 4,4'-methylenebis(2 - ethyl)aniline.

[0013] In some embodiments, for the method for preparing a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite according to the present invention, the first solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, methanol, and acetonitrile; the second solvent includes at least one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0014] In some embodiments, for the method for preparing a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite according to the present invention, the catalyst includes at least one of tetraethylammonium bromide, tetrabutylammonium bromide, benzyltriethylammonium chloride, and dodecyltrimethylammonium chloride.

[0015] In some embodiments, for the method for preparing a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite according to the present invention, the glycidyl-type epoxy resin includes at least one of 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, 3,3'-diethyl-4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, m-phenylenediamine tetraepoxypropyl epoxy resin, p-aminophenol triepoxypropyl epoxy resin, m-aminophenol triepoxypropyl epoxy resin, and phthalic acid diglycidyl epoxy resin.

[0016] In some embodiments, for the method for preparing a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite according to the present invention, the aromatic amine curing agent includes at least one of diethyltoluenediamine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 1,3-bis(4'-aminophenoxy)benzene, and 4,4'-diaminobenzanilide.

[0017] In a second aspect of the present invention, there is provided a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite obtained by the preparation method described in the first aspect of the present invention.

[0018] In a third aspect of the present invention, there is provided an application of the high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite described in the second aspect of the present invention.

[0019] The present invention solves the mutually exclusive bottleneck of "toughness - strength - modulus" of high - strength and high - modulus carbon fibers combined with resin matrix, designs and synthesizes liquid - crystal epoxy monomers with different functionalities, toughens the resin matrix through the liquid - crystal intrinsic mesomorphic domain, synergistically enhances and stiffens with the rigid structure of mesogenic units and intermolecular hydrogen bonds provided by arylamides, and regulates the topological structure of curing cross - linking by the linear bridging of difunctional liquid - crystal monomers and the branched cross - linking of tetrafunctional liquid - crystal monomers, forming a triple - network structure of "liquid - crystal ordered region - hydrogen - bond association domain - topological cross - linker", synchronously improving the toughness, strength and stiffness of the resin matrix, and achieving performance matching with the third - generation high - strength, high - modulus and high - toughness carbon fibers. Specifically, the present invention has the following advantages:

[0020] 1. Based on the molecular - structure design, the present invention synthesizes linear difunctional and three - dimensional tetrafunctional liquid - crystal epoxy monomers, controls the distribution state of mesogenic domains in the resin matrix by regulating the content of liquid - crystal epoxy with different functionalities, forms a nano - scale buffer phase with gradient orientation, and endows the resin with dynamic energy - dissipation ability by the orientation reconstruction of dynamic stress response under load, significantly improving the toughness of the resin matrix.

[0021] 2. Based on the imide and arylamide groups in the mesogenic units of liquid - crystal epoxy monomers with different functionalities, the present invention introduces hydrogen - bond sites to form a high - density hydrogen - bond network with the abundant hydroxyl groups in the resin matrix, and provides an additional π - π conjugation effect through the rigid aromatic condensed - ring skeleton, synergistically enhancing the strength and stiffness of the resin matrix.

[0022] 3. Based on the dynamic regulation of the cross - link network topological structure by liquid - crystal epoxy functionality, through the cooperation of the linear extension of difunctional liquid - crystal epoxy and the three - dimensional cross - linking of tetrafunctional liquid - crystal epoxy, the present invention realizes the balanced optimization of the cross - link density and the molecular weight between cross - link points of the resin matrix, simultaneously improves the toughness, strength and modulus of the resin matrix, effectively enhances the compatibility and performance matching between high - strength and high - modulus carbon fibers and the resin matrix, and realizes the improvement of the comprehensive performance of the third - generation composite materials. Detailed implementation mode

[0023] The various exemplary implementation modes of the present invention will be described in detail below. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing specific implementation modes and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Each intermediate value within any stated value or stated range and each smaller range between any other stated value or intermediate value within the stated range are also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0025] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0026] Preparation method

[0027] One aspect of the present invention provides a method for preparing a high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite.

[0028] In a preferred embodiment, the preparation method of the present invention comprises the following steps:

[0029] (1) Dissolve an aromatic dianhydride and a phenolic amine in a first solvent, adjust the pH value to 8 - 11 (such as 8, 8.5, 9, 9.5, 10, 10.5, 11), and react at 100 - 160 °C (such as 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160 °C) for 8 - 12 h (such as 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12 h) to obtain a bifunctional liquid crystal intermediate P1. Dissolve an aromatic dianhydride and a diamine in a second solvent, and react at 120 - 180 °C (preferably 130 - 180 °C, more preferably 140 - 180 °C, such as 140, 145, 150, 155, 160, 165, 170, 175, 180 °C) for 10 - 16 h (such as 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 1, 15.5, 16 h) to obtain a tetrafunctional liquid crystal intermediate P2. Dissolve the intermediates P1 and P2 in epichlorohydrin respectively, and react at 70 - 90 °C (such as 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90 °C) for 24 - 48 h (such as 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 h), and continue to react at 30 - 50 °C (such as 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50 °C) for 2 - 4 h (such as 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4 h) in the presence of a catalyst and an alkaline solution to obtain a bifunctional liquid crystal epoxy monomer and a tetrafunctional liquid crystal epoxy monomer respectively. The first solvent and the second solvent can be the same or different;

[0030] (2) Mix the glycidyl epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent to obtain a high-strength, high-modulus and high-toughness epoxy resin composition;

[0031] (3) Combine and cure the high-strength, high-modulus and high-toughness epoxy resin composition with high-strength, high-modulus and high-toughness carbon fiber to obtain the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material.

[0032] In step (1) of the present invention, an alkali-containing solution is used to adjust the pH value to 8 - 11. The alkali-containing solution is not particularly limited, and its examples include but are not limited to triethylamine solution, triethylenediamine solution, tetramethylethylenediamine solution, etc. The examples of the alkaline solution include but are not limited to sodium hydroxide solution, potassium hydroxide solution, ammonia water solution, etc.

[0033] In the present invention, the bifunctional liquid crystal epoxy monomer and the tetrafunctional liquid crystal epoxy monomer can be extracted and purified using a polar solvent. The polar solvent is not particularly limited as long as it can achieve the purpose of purification. Its examples include but are not limited to toluene, chloroform, dichloromethane, deionized water, etc.

[0034] In the present invention, in order to improve the strength, modulus and toughness of the epoxy resin-based carbon fiber composite material, the molar ratio of the reactants should not be too high or too low, and the dosage of the catalyst can be controlled within a suitable range. In the present invention, the molar ratio of the aromatic dianhydride to the phenolic amine is 1:(2 - 4), such as 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4; the molar ratio of the aromatic dianhydride to the diamine is 1:(2 - 6), such as 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4, 1:4.2, 1:4.4, 1:4.6, 1:4.8, 1:5, 1:5.2, 1:5.4, 1:5.6, 1:5.8, 1:6; the molar ratio of the intermediate P1 or P2 to epichlorohydrin is 1:(6 - 12), such as 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12; the addition amount of the catalyst is 0.2% - 0.5% of the total mass of the reaction system, such as 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%.

[0035] In a preferred embodiment, the molar ratio of the aromatic dianhydride to the phenolamine is 1:2, the molar ratio of the aromatic dianhydride to the diamine is 1:2, the molar ratio of the intermediate P1 to epichlorohydrin is 1:8, the molar ratio of the intermediate P2 to epichlorohydrin is 1:10, the addition amount of the catalyst in the preparation process of the intermediate P1 is 0.3% of the total mass of the reaction system, and the addition amount of the catalyst in the preparation process of the intermediate P2 is 0.5% of the total mass of the reaction system. In another preferred embodiment, the molar ratio of the aromatic dianhydride to the phenolamine is 1:2, the molar ratio of the aromatic dianhydride to the diamine is 1:2, the molar ratio of the intermediate P1 to epichlorohydrin is 1:6, the molar ratio of the intermediate P2 to epichlorohydrin is 1:12, the addition amount of the catalyst in the preparation process of the intermediate P1 is 0.2% of the total mass of the reaction system, and the addition amount of the catalyst in the preparation process of the intermediate P2 is 0.4% of the total mass of the reaction system. In yet another preferred embodiment, the molar ratio of the aromatic dianhydride to the phenolamine is 1:2, the molar ratio of the aromatic dianhydride to the diamine is 1:2, the molar ratio of the intermediate P1 to epichlorohydrin is 1:6, the molar ratio of the intermediate P2 to epichlorohydrin is 1:10, the addition amount of the catalyst in the preparation process of the intermediate P1 is 0.3% of the total mass of the reaction system, and the addition amount of the catalyst in the preparation process of the intermediate P2 is 0.4% of the total mass of the reaction system.

[0036] In the present invention, in order to improve the strength, modulus and toughness of the epoxy resin-based carbon fiber composite, the molar ratio of the reactants should not be too high or too low. In the present invention, the mass ratio of the glycidyl epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:(10 - 30):(20 - 40):(35 - 45), such as 100:10:20:35, 100:15:20:35, 100:20:20:35, 100:25:20:35, 100:30:20:35, 100:10:25:35, 100:10:30:35, 100:10:35:35, 100:10:40:35, 100:10:20:40, 100:10:20:45, 100:10:40:45, 100:20:30:40, or any value within the above range.

[0037] In a preferred embodiment, the mass ratio of the glycidyl epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:10:40:45. In another preferred embodiment, the mass ratio of the glycidyl epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:20:30:40. In yet another preferred embodiment, the mass ratio of the glycidyl epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:30:20:35.

[0038] In the present invention, the type of the aromatic dianhydride is not particularly limited, and examples thereof include, but are not limited to, at least one of pyromellitic dianhydride, naphthalene tetracarboxylic dianhydride, and perylene tetracarboxylic dianhydride; the type of the phenolamine is not particularly limited, and examples thereof include, but are not limited to, at least one of p-aminophenol, m-aminophenol, p-hydroxyphenethylamine, 2-amino-4-hydroxybenzamide, and N-(4-aminophenyl)-3-hydroxybenzamide; the type of the diamine is not particularly limited, and examples thereof include, but are not limited to, at least one of p-phenylenediamine, m-phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide, and 4,4'-methylenebis(2-ethyl)aniline.

[0039] In a preferred embodiment, the aromatic dianhydride is pyromellitic dianhydride, the phenolamine is N-(4-aminophenyl)-3-hydroxybenzamide, and the diamine is 4,4'-diaminobenzanilide. In another preferred embodiment, the aromatic dianhydride is pyromellitic dianhydride, the phenolamine is N-(4-aminophenyl)-3-hydroxybenzamide, and the diamine is 3,3'-diaminobenzanilide. In yet another preferred embodiment, the aromatic dianhydride is pyromellitic dianhydride, the phenolamine is 2-amino-4-hydroxybenzamide, and the diamine is 4,4'-diaminobenzanilide.

[0040] In the present invention, the first solvent includes at least one of N-methylpyrrolidone, N,N-dimethylformamide, methanol, and acetonitrile; the second solvent includes at least one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide. In a preferred embodiment, the first solvent is N,N-dimethylformamide and the second solvent is N-methylpyrrolidone. In another preferred embodiment, the first solvent is N,N-dimethylformamide and the second solvent is N,N-dimethylformamide. In yet another preferred embodiment, the first solvent is N-methylpyrrolidone and the second solvent is N,N-dimethylformamide.

[0041] In the present invention, the type of the catalyst is not particularly limited, and examples thereof include but are not limited to at least one of tetraethylammonium bromide, tetrabutylammonium bromide, benzyltriethylammonium chloride, and dodecyltrimethylammonium chloride. In a preferred embodiment, the catalyst in the preparation process of the bifunctional liquid crystal epoxy monomer is tetrabutylammonium bromide, and the catalyst in the preparation process of the tetrafunctional liquid crystal epoxy monomer is benzyltriethylammonium chloride. In another preferred embodiment, the catalyst in the preparation process of the bifunctional liquid crystal epoxy monomer is tetraethylammonium bromide, and the catalyst in the preparation process of the tetrafunctional liquid crystal epoxy monomer is tetrabutylammonium bromide. In yet another preferred embodiment, the catalyst in the preparation process of the bifunctional liquid crystal epoxy monomer is tetrabutylammonium bromide, and the catalyst in the preparation process of the tetrafunctional liquid crystal epoxy monomer is tetrabutylammonium bromide.

[0042] In the present invention, the type of the glycidyl-type epoxy resin is not particularly limited, and examples thereof include but are not limited to at least one of 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, 3,3'-diethyl-4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, m-xylylenediamine tetraepoxypropyl epoxy resin, p-aminophenol triepoxypropyl epoxy resin, m-aminophenol triepoxypropyl epoxy resin, and phthalic acid diglycidyl epoxy resin. In a preferred embodiment, the glycidyl-type epoxy resin is 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin.

[0043] In the present invention, the type of the aromatic amine curing agent is not particularly limited, and examples thereof include but are not limited to at least one of diethyltoluenediamine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 1,3-bis(4'-aminophenoxy)benzene, and 4,4'-diaminobenzanilide. In a preferred embodiment, the aromatic amine curing agent is 4,4'-diaminodiphenyl sulfone.

[0044] In the present invention, the high-strength, high-modulus, and high-toughness carbon fiber is not particularly limited, and any carbon fiber with high strength, high modulus, and high toughness known in the art can be used, such as domestic M40X grade, domestic T1100G grade carbon fiber, etc.

[0045] Carbon fiber composite material

[0046] In one aspect of the present invention, there is provided a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite material obtained by the preparation method of the present invention.

[0047] In a preferred embodiment, the high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite material of the present invention has not less than 363 J / m 2The interlaminar fracture toughness is not less than 1671 MPa, the flexural strength is not less than 189 GPa, and the flexural modulus is not less than 189 GPa.

[0048] Application

[0049] One aspect of the present invention provides an application of the high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite according to the present invention. The application is not particularly limited, and its examples include but are not limited to aerospace (such as but not limited to antenna reflectors, antenna brackets, waveguides, etc.), high-end equipment (such as but not limited to missile casings, ship decks, etc.), ocean engineering (such as but not limited to pressure-resistant structural parts, pipe fittings, etc.), civil construction (such as but not limited to solar panels, etc.), transportation (such as but not limited to battery boxes, chassis structural parts, body shells, etc.), etc.

[0050] Example 1

[0051] The following shows the preparation method of the high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite.

[0052] (1) Synthesis of difunctional and tetrafunctional liquid crystal epoxy monomers: Under nitrogen protection, pyromellitic dianhydride and N-(4-aminophenyl)-3-hydroxybenzamide were dissolved in N,N-dimethylformamide at a molar ratio of 1:2, and triethylamine solution was added dropwise to adjust the pH to 11 and react at 160 °C for 8 h. After cooling, filtration and drying were carried out to obtain a liquid crystal intermediate P1 with terminal phenolic hydroxyl groups; P1 was dissolved in epichlorohydrin at a molar ratio of 1:8, reacted at 90 °C for 24 h, and then cooled to room temperature. 0.3% of the total mass of the reaction system of tetrabutylammonium bromide was added, and an aqueous solution of 30% NaOH was slowly added dropwise within 0.5 h, and the reaction was continued at 50 °C for 2 h. The reaction solution was extracted with dichloromethane, washed with deionized water until neutral, and the solvent was removed by vacuum distillation to obtain a difunctional liquid crystal epoxy monomer. Under nitrogen protection, pyromellitic dianhydride and 4,4'-diaminobenzanilide were dissolved in N-methylpyrrolidone at a molar ratio of 1:2, reacted at 180 °C for 12 h, and after cooling, filtration and drying were carried out to obtain a liquid crystal intermediate P2 with terminal amino groups; P2 was dissolved in epichlorohydrin at a molar ratio of 1:10, reacted at 90 °C for 24 h, and then cooled to room temperature. 0.5% of the total mass of the reaction system of benzyltriethylammonium chloride was added, and an aqueous solution of 40% NaOH was slowly added dropwise within 0.5 h, and the reaction was carried out at 50 °C for 3 h. The reaction solution was extracted with toluene, washed with deionized water until neutral, and the solvent was removed by vacuum distillation to obtain a tetrafunctional liquid crystal epoxy monomer.

[0053] (2) Add 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, the bifunctional and tetrafunctional liquid crystal epoxy monomers obtained in step (1), and 4,4'-diaminodiphenyl sulfone to a high-speed stirring kettle in a ratio of 100:10:40:45, mix at 130 °C for 30 minutes, and obtain a curable high-strength, high-modulus, and high-toughness epoxy resin composition after vacuum degassing.

[0054] (3) Compound high-strength, high-modulus, and high-toughness carbon fiber (domestic M40X grade) with the epoxy resin composition obtained in step (2), and cure by heating according to the curing system of 180 °C / 2 h + 200 °C / 2 h to obtain a high-strength, high-modulus, and high-toughness carbon fiber composite based on epoxy resin.

[0055] Example 2

[0056] The following shows the preparation method of a high-strength, high-modulus, and high-toughness carbon fiber composite based on epoxy resin.

[0057] (1) Synthesis of bifunctional and tetrafunctional liquid crystal epoxy monomers: Under nitrogen protection, dissolve pyromellitic dianhydride and N-(4-aminophenyl)-3-hydroxybenzamide in N,N-dimethylformamide in a molar ratio of 1:2, add a triethylenediamine solution to adjust the pH to 9 and react at 140 °C for 10 h. After cooling, filter and dry to obtain a liquid crystal intermediate P1 with terminal phenolic hydroxyl groups; dissolve P1 in epichlorohydrin in a molar ratio of 1:6, react at 80 °C for 36 h, then cool to room temperature, add tetraethylammonium bromide accounting for 0.2% of the total mass of the reaction system, and slowly dropwise add a 30% NaOH aqueous solution within 0.5 h, and continue to react at 40 °C for 3 h. Extract the reaction solution with dichloromethane, wash with deionized water until neutral, and remove the solvent by vacuum distillation to obtain a bifunctional liquid crystal epoxy monomer. Under nitrogen protection, dissolve pyromellitic dianhydride and 3,3'-diaminobenzanilide in N,N-dimethylformamide in a molar ratio of 1:2, react at 160 °C for 16 h, cool, filter, and dry to obtain a liquid crystal intermediate P2 with terminal amino groups; dissolve P2 in epichlorohydrin in a molar ratio of 1:12, react at 80 °C for 36 h, then cool to room temperature, add tetrabutylammonium bromide accounting for 0.4% of the total mass of the reaction system, slowly dropwise add a 40% NaOH aqueous solution within 0.5 h, and react at 40 °C for 4 h. Extract the reaction solution with toluene, wash with deionized water until neutral, and remove the solvent by vacuum distillation to obtain a tetrafunctional liquid crystal epoxy monomer.

[0058] (2) Add 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, the bifunctional and tetrafunctional liquid crystal epoxy monomers obtained in step (1), and 4,4'-diaminodiphenyl sulfone to a high-speed stirring kettle in a ratio of 100:20:30:40, mix at 130 °C for 30 minutes, and obtain a curable high-strength, high-modulus, and high-toughness epoxy resin composition after vacuum degassing.

[0059] (3) Compound the high-strength, high-modulus and high-toughness carbon fiber (domestic M40X grade) with the epoxy resin composition obtained in step (2), and cure it by heating according to the curing regime of 180 °C / 2 h + 200 °C / 2 h to obtain a high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material.

[0060] Example 3

[0061] The following shows the preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material.

[0062] (1) Synthesis of difunctional and tetrafunctional liquid crystal epoxy monomers: Under nitrogen protection, dissolve pyromellitic dianhydride and 2-amino-4-hydroxybenzamide in N-methylpyrrolidone at a molar ratio of 1:2, add a solution of tetramethylethylenediamine to adjust the pH to 8 and react at 100 °C for 12 h. After cooling, filter and dry to obtain a liquid crystal intermediate P1 with terminal phenolic hydroxyl groups; dissolve P1 in epichlorohydrin at a molar ratio of 1:6, react at 70 °C for 48 h, then cool to room temperature, add tetrabutylammonium bromide accounting for 0.3% of the total mass of the reaction system, and slowly dropwise add an aqueous solution of 30% NaOH within 0.5 h, and continue to react at 40 °C for 3 h. Extract the reaction solution with toluene, wash it with deionized water until neutral, and remove the solvent by vacuum distillation to obtain a difunctional liquid crystal epoxy monomer. Under nitrogen protection, dissolve pyromellitic dianhydride and 4,4'-diaminobenzanilide in N,N-dimethylformamide at a molar ratio of 1:2, react at 180 °C for 12 h. After cooling, filter and dry to obtain a liquid crystal intermediate P2 with terminal amino groups; dissolve P2 in epichlorohydrin at a molar ratio of 1:10, react at 70 °C for 48 h, then cool to room temperature, add tetrabutylammonium bromide accounting for 0.4% of the total mass of the reaction system, slowly dropwise add an aqueous solution of 40% NaOH within 0.5 h, and react at 50 °C for 3 h. Extract the reaction solution with dichloromethane, wash it with deionized water until neutral, and remove the solvent by vacuum distillation to obtain a tetrafunctional liquid crystal epoxy monomer.

[0063] (2) Add 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, the difunctional and tetrafunctional liquid crystal epoxy monomers obtained in step (1), and 4,4'-diaminodiphenyl sulfone to a high-speed stirring kettle at a ratio of 100:30:20:35, mix at 130 °C for 30 minutes, and perform vacuum degassing to obtain a curable high-strength, high-modulus and high-toughness epoxy resin composition.

[0064] (3) Compound the high-strength, high-modulus and high-toughness carbon fiber (domestic T1100G grade) with the epoxy resin composition obtained in step (2), and cure it by heating according to the curing regime of 180 °C / 2 h + 200 °C / 2 h to obtain a high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material.

[0065] Comparative Example 1

[0066] The following is a method for preparing an epoxy resin-based carbon fiber composite material.

[0067] (1) Synthesis of bifunctional liquid crystal epoxy monomer: Under nitrogen protection, pyromellitic dianhydride and N-(4-aminophenyl)-3-hydroxybenzamide were dissolved in N,N-dimethylformamide at a molar ratio of 1:2, triethylamine solution was added dropwise to adjust the pH to 9, and the mixture was reacted at 140°C for 10 hours. After cooling, the mixture was filtered and dried to obtain a liquid crystal intermediate P1 with a terminal phenolic hydroxyl group. P1 was dissolved in epichlorohydrin at a molar ratio of 1:6, and the mixture was reacted at 80°C for 30 hours. After cooling to room temperature, 0.2% of the total mass of the reaction system was added with tetrabutylammonium bromide, and a 30% NaOH aqueous solution was slowly added dropwise over 0.5 hours. The reaction was continued at 40°C for 3 hours. The reaction solution was extracted with dichloromethane, washed with deionized water until neutral, and the solvent was removed by vacuum distillation to obtain a bifunctional liquid crystal epoxy monomer.

[0068] (2) Add 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, the bifunctional liquid crystal epoxy monomer obtained in step (1) and 4,4'-diaminodiphenyl sulfone into a high-speed stirring kettle at a ratio of 100:30:35, mix at 130°C for 30 minutes, and obtain a curable high-strength, high-modulus and high-toughness epoxy resin composition after vacuum degassing.

[0069] (3) Compounding high-strength, high-modulus, high-toughness carbon fiber (domestic M40X grade) with the epoxy resin composition obtained in step (2), heating and curing according to a curing system of 180°C / 2h+200°C / 2h to obtain a high-strength, high-modulus, high-toughness epoxy resin-based carbon fiber composite material.

[0070] Comparative Example 2

[0071] The following is a method for preparing an epoxy resin-based carbon fiber composite material.

[0072] (1) Synthesis of a tetrafunctional liquid crystal epoxy monomer: Under nitrogen protection, pyromellitic dianhydride and 4,4'-diaminobenzanilide were dissolved in N-methylpyrrolidone at a molar ratio of 1:2, reacted at 180°C for 12 hours, cooled, filtered, and dried to obtain an amino-terminated liquid crystal intermediate P2; P2 was dissolved in epichlorohydrin at a molar ratio of 1:10, reacted at 90°C for 24 hours, then cooled to room temperature, and 0.5% of the total mass of the reaction system was added to benzyltriethylammonium chloride. A 40% aqueous solution of NaOH was slowly added dropwise over 0.5 hours, and the reaction was continued at 50°C for 3 hours. The reaction solution was extracted with toluene, washed with deionized water until neutral, and the solvent was removed by distillation under reduced pressure to obtain a tetrafunctional liquid crystal epoxy monomer.

[0073] (2) Add 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, the tetrafunctional liquid crystal epoxy monomer obtained in step (1), and 4,4'-diaminodiphenyl sulfone into a high-speed stirring kettle in a ratio of 100:30:40, mix at 130 °C for 30 minutes, and obtain a curable high-strength, high-modulus, and high-toughness epoxy resin composition after vacuum degassing.

[0074] (3) Compound high-strength, high-modulus, and high-toughness carbon fiber (domestic M40X grade) with the epoxy resin composition obtained in step (2), and heat and cure according to the curing system of 180 °C / 2h + 200 °C / 2h to obtain a high-strength, high-modulus, and high-toughness epoxy resin-based carbon fiber composite.

[0075] Comparative Example 3

[0076] The following shows the preparation method of the epoxy resin-based carbon fiber composite.

[0077] Prepare a curable epoxy resin composition from 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin and 4,4'-diaminodiphenyl sulfone in a ratio of 100:30, compound it with high-strength, high-modulus, and high-toughness carbon fiber (domestic M40X grade), and heat and cure according to the curing system of 180 °C / 2h + 200 °C / 2h to obtain an epoxy resin-based carbon fiber composite.

[0078] Detect the properties of the epoxy resin-based carbon fiber composites of Examples 1, 2, 3 and Comparative Examples 1, 2, 3, and the results are shown in Table 1.

[0079] Table 1 Comparison of the properties of the composites of Examples 1, 2, 3 and Comparative Examples 1, 2, 3

[0080]

[0081] The results show that through the controllable functionalization treatment of the end groups of the liquid crystal polymer, the present invention designs bifunctional linear and polyfunctional three-dimensional molecular structures, precisely regulates the topological structure of the ordered orientation polymer network in the resin matrix, and synergistically improves the toughness, strength, and modulus of the epoxy resin matrix, ultimately realizing the comprehensive improvement of the mechanical properties of the third-generation high-strength, high-modulus, and high-toughness carbon fiber composites.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A preparation method of a high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material, characterized in that, It includes the following steps: (1) Dissolve an aromatic dianhydride and a phenolamine in a first solvent, react at 100 - 160 °C for 8 - 12 h under alkaline conditions to obtain a bifunctional liquid crystal intermediate P1. Dissolve the aromatic dianhydride and a diamine in a second solvent, react at 120 - 180 °C for 10 - 16 h to obtain a tetrafunctional liquid crystal intermediate P2. Dissolve the intermediates P1 and P2 in epichlorohydrin respectively, react at 70 - 90 °C for 24 - 48 h, and continue to react at 30 - 50 °C for 2 - 4 h in the presence of a catalyst and an alkaline solution to obtain a bifunctional liquid crystal epoxy monomer and a tetrafunctional liquid crystal epoxy monomer respectively. The first solvent and the second solvent may be the same or different; (2) Mix a glycidyl-type epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and an aromatic amine curing agent to obtain a high-strength, high-modulus and high-toughness epoxy resin composition; (3) Composite and cure the high-strength, high-modulus and high-toughness epoxy resin composition with high-strength, high-modulus and high-toughness carbon fiber to obtain the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material.

2. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, wherein, In step (1), the molar ratio of the aromatic dianhydride to the phenolamine is 1:(2 - 4); the molar ratio of the aromatic dianhydride to the diamine is 1:(2 - 6); the molar ratio of the intermediate P1 or P2 to epichlorohydrin is 1:(6 - 12); the addition amount of the catalyst is 0.2% - 0.5% of the total mass of the reaction system.

3. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, characterized in that, In step (2), the mass ratio of the glycidyl-type epoxy resin, the bifunctional liquid crystal epoxy monomer, the tetrafunctional liquid crystal epoxy monomer and the aromatic amine curing agent is 100:(10 - 30):(20 - 40):(35 - 45).

4. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, characterized in that, The aromatic dianhydride includes at least one of pyromellitic dianhydride, naphthalene tetracarboxylic dianhydride and perylene tetracarboxylic dianhydride; the phenolamine includes at least one of p-aminophenol, m-aminophenol, p-hydroxyphenethylamine, 2-amino-4-hydroxybenzamide and N-(4-aminophenyl)-3-hydroxybenzamide; the diamine includes at least one of p-phenylenediamine, m-phenylenediamine, 4,4'-diaminobenzanilide, 3,3'-diaminobenzanilide and 4,4'-methylenebis(2-ethyl)aniline.

5. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, characterized in that, The first solvent and the second solvent are each independently selected from at least one of N-methylpyrrolidone, N,N-dimethylformamide, methanol, acetonitrile and dimethyl sulfoxide.

6. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, characterized in that, The catalyst includes at least one of tetraethylammonium bromide, tetrabutylammonium bromide, benzyltriethylammonium chloride and dodecyltrimethylammonium chloride.

7. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, wherein, The glycidyl-type epoxy resin includes at least one of 4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, 3,3'-diethyl-4,4'-diaminodiphenylmethane tetraepoxypropyl epoxy resin, m-xylenediamine tetraepoxypropyl epoxy resin, p-aminophenol triepoxypropyl epoxy resin, m-aminophenol triepoxypropyl epoxy resin and phthalic acid diepoxypropyl epoxy resin.

8. The preparation method of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite according to claim 1, characterized in that, The aromatic amine curing agent includes at least one of diethyltoluenediamine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 1,3-bis(4'-aminophenoxy)benzene, and 4,4'-diaminobenzanilide.

9. A high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite, characterized in that, It is obtained by the preparation method according to any one of claims 1-8.

10. Use of the high-strength, high-modulus and high-toughness epoxy resin-based carbon fiber composite material according to claim 9.

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