A lightweight high-strength fiber composite material and its preparation method

Abstract

This invention discloses a lightweight high-strength fiber composite material and its preparation method. The raw materials include 35-45 parts of T700 grade carbon fiber cloth and 55-65 parts of a ternary matrix. The ternary matrix is ​​obtained by melt blending polyethersulfone, lignin, and organo-modified montmorillonite. The composite material is prepared by impregnating the carbon fiber cloth with the ternary matrix solution via a phase inversion method, followed by deionized water phase inversion, drying, and reaction at 120°C. Its biomimetic bamboo-like "fiber-porous matrix" structure forms a ternary complementary system with a tensile strength of 680 MPa and a density of 1.35-1.45 g / cm³. 3 It improves fracture toughness and interfacial shear strength, reduces costs, and is suitable for high-end manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of novel materials technology, specifically relating to a lightweight high-strength fiber composite material and its preparation method. Background Technology

[0002] Fiber-reinforced composite materials, with their high specific strength, high specific modulus, and strong designability, have become core materials for achieving structural lightweighting and performance optimization in high-end manufacturing fields such as aerospace and rail transportation. Taking aerospace as an example, the Boeing 787's fuselage structure uses approximately 50% carbon fiber reinforced composite materials, reducing the overall weight by about 20% compared to traditional aluminum alloy structures and improving fuel efficiency by 15%–20%. Similarly, the Airbus A350XWB effectively reduces fuselage weight through extensive use of composite materials, thereby lowering operating costs and enhancing market competitiveness. In rail transportation, CRRC's carbon fiber composite subway car bodies reduce weight by more than 30% compared to traditional steel car bodies, significantly reducing energy consumption and improving train speed and passenger comfort, providing strong support for green and low-carbon travel.

[0003] However, the development of materials science has always faced the challenge of synergistic multi-objective objectives. Currently, fiber-reinforced composite materials exhibit three major bottlenecks in practical applications: First, there is an irreconcilable contradiction between the strength, toughness, and lightweighting of materials. From a materials mechanics perspective, when the density of fiber-reinforced composite materials decreases, their internal load-bearing structure is inevitably affected. The effective load-bearing area between the fiber and the matrix decreases, making the material more susceptible to failure under stress. For example, in some extreme lightweight designs, the strength and toughness reduction rate can reach 15%–20%, seriously affecting the reliability and safety of the structure. Second, the interface design between the fiber and the matrix lacks systematic theoretical guidance. Insufficient or excessive interfacial bonding strength will affect the overall performance of the material. As the key area for load transfer between the fiber and the matrix, the interface directly determines the mechanical behavior of the composite material. Insufficient bonding strength can easily lead to debonding between the fiber and the matrix, resulting in stress concentration; excessive bonding limits the fiber's ability to deform collaboratively, causing the material to exhibit brittle fracture characteristics. Third, the complex manufacturing process and the cost of high-performance raw materials pose economic challenges for large-scale industrial applications. Taking autoclave molding as an example, although this process can produce high-performance composite material components, it requires large equipment investment, consumes a lot of energy, and has a long production cycle, which severely restricts its application in low-cost fields. Meanwhile, the high prices of raw materials such as high-performance carbon fibers further increase the manufacturing cost of composite materials. These technological barriers that need to be overcome not only restrict the expansion of fiber composite material applications but also provide clear directions for the research and development of new material systems and preparation processes. Summary of the Invention

[0004] The purpose of this invention is to provide a lightweight high-strength fiber composite material and its preparation method to solve the problems in the background art.

[0005] The core improvement of this invention is as follows: Based on the natural composite structure of bamboo's "fiber-porous matrix", carbon fiber is used as the reinforcing phase to simulate bamboo fiber. Polyethersulfone (PES) modified with lignin and organic montmorillonite (OMMT) is used as the porous matrix to replace natural lignin. Through phase transformation, the ether groups in the polyethersulfone molecular structure give it good toughness, while the sulfone groups provide heat resistance and self-extinguishing properties without flame retardants. The conjugated diphenyl sulfone groups enable a tensile strength of 84.3 MPa. Lignin is both a natural matrix component and a functional additive to enhance interfacial bonding, achieving a dual match between "biomimicry and performance". The introduction of organic montmorillonite compensates for the weakening of matrix strength by lignin, forming a ternary complementary system.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A lightweight, high-strength fiber composite material comprises the following raw materials in parts by weight:

[0008] 35-45 parts of T700 grade carbon fiber cloth;

[0009] 55 to 65 parts of ternary matrix;

[0010] Furthermore, the ternary matrix is ​​prepared by the following steps:

[0011] T1. Dry lignin at 60°C for 8 hours, dry polyethersulfone resin at 120°C for 12 hours, then put lignin and polyethersulfone resin into a mixer and stir at 800 r / min for 10 minutes, then add organo-modified montmorillonite and continue stirring at 800 r / min for 15 minutes to obtain a premix.

[0012] T2. Set the temperature of each section of the twin-screw extruder as follows: Zone 1 280℃, Zone 2 290℃, Zone 3 300℃, Zone 4 305℃, Zone 5 300℃, and Die 295℃. Add the premix to the hopper of the twin-screw extruder and melt-blend extrusion at a screw speed of 20r / min. After the extrudate is water-cooled and stretched, it is cut into 3-5mm long particles using a pelletizer. The particles are vacuum dried at 80℃ for 6 hours to obtain the ternary matrix.

[0013] Furthermore, the ratio of polyethersulfone, lignin and organo-modified montmorillonite in T1 is 70-80g:15-25g:4-6g.

[0014] Furthermore, a method for preparing a lightweight high-strength fiber composite material includes the following steps:

[0015] S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, the mass ratio of matrix particles to solvent is 15:85, stir at 80°C for 2 hours to form a homogeneous solution;

[0016] S2. Immerse the T700 grade carbon fiber cloth in the solution until the solution is completely absorbed. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water and leave it for 10 minutes to allow the solvent to fully dissolve in the deionized water. After removing it, dry it at 60°C for 4 hours to obtain the dried composite material.

[0017] S3. The dried composite material is reacted at 120°C for 20-40 minutes to promote the interfacial reaction between lignin and carbon fiber, while the organic montmorillonite sheets are further stretched, increasing the matrix density and obtaining a lightweight high-strength fiber composite material.

[0018] Furthermore, the mass of the deionized water in S2 is more than 10 times the mass of the impregnated carbon fiber cloth.

[0019] The beneficial effects of this invention are:

[0020] Carbon fiber, acting as a reinforcing phase, bears the main load and forms a "rigid skeleton-flexible buffer" structure with the ternary matrix, enabling the composite material to achieve a tensile strength of 680 MPa and an overall density of only 1.35–1.45 g / cm³. 3 .

[0021] The synergistic effect of lignin's flexible chain segments and the lamellar structure of organo-modified montmorillonite: lignin absorbs energy through molecular chain slippage, while organo-modified montmorillonite disperses stress through crack deflection, resulting in a fracture toughness (KIC) of 7.2 MPa·m for the composite material. 1 / 2 This represents a 60% improvement over pure polyethersulfone matrix composites. In collision scenarios, the porous structure further buffers impact, increasing impact resistance to 80 kJ / m². 2 .

[0022] The phenolic hydroxyl groups of lignin form hydrogen bonds with the hydroxyl groups on the carbon fiber surface. Combined with the nanoscale anchoring effect of organo-modified montmorillonite, the shear strength at the fiber-matrix interface reaches 61 MPa, which is 35% higher than that of the unmodified system. This optimization solves the pain point of "interfacial debonding" in traditional composite materials.

[0023] Replacing some of the polyethersulfone with lignin reduces the cost of the matrix raw materials; at the same time, the addition of organic montmorillonite achieves a leap in performance with a small amount, avoiding the excessive use of expensive reinforcing agents. The overall material cost is reduced by 25% compared to pure carbon fiber / polyethersulfone composites. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials, reagents, or devices used in the following embodiments can be obtained from conventional commercial channels or by existing known methods.

[0025] Example 1

[0026] The ternary matrix is ​​prepared by the following steps:

[0027] T1. Dry 150g of lignin (purchased from Shanghai Tingruo Chemical Co., Ltd.) at 60℃ for 8 hours, and dry 700g of polyethersulfone resin (purchased from Nagase Group) at 120℃ for 12 hours. Then, put the lignin and polyethersulfone resin into a mixer and stir at 800r / min for 10 minutes. Then, add 40g of organo-modified montmorillonite (purchased from Zhejiang Fenghong New Material Co., Ltd.) and continue stirring at 800r / min for 15 minutes to obtain a premix.

[0028] T2. Set the temperature of each section of the twin-screw extruder as follows: Zone 1 280℃, Zone 2 290℃, Zone 3 300℃, Zone 4 305℃, Zone 5 300℃, and Die 295℃. Add the premix to the hopper of the twin-screw extruder and melt-blend extrusion at a screw speed of 20r / min. After the extrudate is water-cooled and stretched, it is cut into 3mm long particles using a pelletizer. The particles are vacuum dried at 80℃ for 6 hours to obtain the ternary matrix.

[0029] Example 2

[0030] The ternary matrix is ​​prepared by the following steps:

[0031] T1. Dry 200g of lignin (purchased from Shanghai Tingruo Chemical Co., Ltd.) at 60℃ for 8 hours, and dry 750g of polyethersulfone resin (purchased from Nagase Group) at 120℃ for 12 hours. Then, put the lignin and polyethersulfone resin into a mixer and stir at 800r / min for 10 minutes. Then, add 50g of organo-modified montmorillonite (purchased from Zhejiang Fenghong New Material Co., Ltd.) and continue stirring at 800r / min for 15 minutes to obtain a premix.

[0032] T2. Set the temperature of each section of the twin-screw extruder as follows: Zone 1 280℃, Zone 2 290℃, Zone 3 300℃, Zone 4 305℃, Zone 5 300℃, and Die 295℃. Add the premix to the hopper of the twin-screw extruder and melt-blend extrusion at a screw speed of 20r / min. After water cooling and stretching, the extrudate is cut into 4mm long particles using a pelletizer. The particles are vacuum dried at 80℃ for 6 hours to obtain the ternary matrix.

[0033] Example 3

[0034] The ternary matrix is ​​prepared by the following steps:

[0035] T1. Dry 250g of lignin (purchased from Shanghai Tingruo Chemical Co., Ltd.) at 60℃ for 8 hours, and dry 800g of polyethersulfone resin (purchased from Nagase Group) at 120℃ for 12 hours. Then, put the lignin and polyethersulfone resin into a mixer and stir at 800r / min for 10 minutes. Then, add 60g of organo-modified montmorillonite (purchased from Zhejiang Fenghong New Material Co., Ltd.) and continue stirring at 800r / min for 15 minutes to obtain a premix.

[0036] T2. Set the temperature of each section of the twin-screw extruder as follows: Zone 1 280℃, Zone 2 290℃, Zone 3 300℃, Zone 4 305℃, Zone 5 300℃, and Die 295℃. Add the premix to the hopper of the twin-screw extruder and melt-blend extrusion at a screw speed of 20r / min. After the extrudate is water-cooled and stretched, it is cut into 5mm long particles using a pelletizer. The particles are vacuum dried at 80℃ for 6 hours to obtain the ternary matrix.

[0037] Example 4

[0038] Preparation of lightweight high-strength fiber composite materials:

[0039] First, the lightweight high-strength fiber composite material comprises the following raw materials by weight:

[0040] 35 units of T700 grade carbon fiber cloth (purchased from Carbon Technology Group Co., Ltd.);

[0041] 55 parts of the ternary matrix prepared in Example 1;

[0042] Then, the preparation method of the above-mentioned lightweight high-strength fiber composite material includes the following steps:

[0043] S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, the mass ratio of matrix particles to solvent is 15:85, stir at 80°C for 2 hours to form a homogeneous solution;

[0044] S2. Immerse the T700 grade carbon fiber cloth in the solution and impregnate it for 60 seconds under a pressure of 0.1 MPa to ensure that the solution is completely absorbed. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water with a mass of more than 10 times that of the impregnated fiber cloth to ensure full phase inversion. Hold for 10 minutes to allow the solvent to fully dissolve in the deionized water. After removal, dry at 60°C for 4 hours to obtain a dried composite material.

[0045] S3. The dried composite material is reacted at 120°C for 20 minutes to promote the interfacial reaction between lignin and carbon fiber, while the organic montmorillonite sheets are further stretched, increasing the matrix density and obtaining a lightweight high-strength fiber composite material.

[0046] Example 5

[0047] Preparation of lightweight high-strength fiber composite materials:

[0048] First, the lightweight high-strength fiber composite material comprises the following raw materials by weight:

[0049] 40 sets of T700 grade carbon fiber cloth (purchased from Carbon Technology Group Co., Ltd.);

[0050] 60 parts of the ternary matrix prepared in Example 2;

[0051] Then, the preparation method of the above-mentioned lightweight high-strength fiber composite material includes the following steps:

[0052] S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, the mass ratio of matrix particles to solvent is 15:85, stir at 80°C for 2 hours to form a homogeneous solution;

[0053] S2. Immerse the T700 grade carbon fiber cloth in the solution and impregnate it for 60 seconds under a pressure of 0.1 MPa to ensure that the solution is completely absorbed. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water with a mass of more than 10 times that of the impregnated fiber cloth to ensure full phase inversion. Hold for 10 minutes to allow the solvent to fully dissolve in the deionized water. After removal, dry at 60°C for 4 hours to obtain a dried composite material.

[0054] S3. The dried composite material is reacted at 120°C for 30 minutes to promote the interfacial reaction between lignin and carbon fiber, while the organic montmorillonite sheets are further stretched, increasing the matrix density and obtaining a lightweight high-strength fiber composite material.

[0055] Example 6

[0056] Preparation of lightweight high-strength fiber composite materials:

[0057] First, the lightweight high-strength fiber composite material comprises the following raw materials by weight:

[0058] 45 units of T700 grade carbon fiber cloth (purchased from Carbon Technology Group Co., Ltd.);

[0059] 65 parts of the ternary matrix prepared in Example 3;

[0060] Then, the preparation method of the above-mentioned lightweight high-strength fiber composite material includes the following steps:

[0061] S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, the mass ratio of matrix particles to solvent is 15:85, stir at 80°C for 2 hours to form a homogeneous solution;

[0062] S2. Immerse the T700 grade carbon fiber cloth in the solution and impregnate it for 60 seconds under a pressure of 0.1 MPa to ensure that the solution is completely absorbed. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water with a mass of more than 10 times that of the impregnated fiber cloth to ensure full phase inversion. Hold for 10 minutes to allow the solvent to fully dissolve in the deionized water. After removal, dry at 60°C for 4 hours to obtain a dried composite material.

[0063] S3. The dried composite material is reacted at 120°C for 40 minutes to promote the interfacial reaction between lignin and carbon fiber, while the organic montmorillonite sheets are further stretched, increasing the matrix density and obtaining a lightweight high-strength fiber composite material.

[0064] Comparative Example 1

[0065] Comparative Example 1 served as the control group for Example 5. In Example 2, the raw material lignin was replaced with polyethersulfone resin, while the remaining raw materials, raw material amounts, and preparation methods remained consistent with those in Example 5. Finally, a lightweight high-strength fiber composite material was obtained.

[0066] Comparative Example 2

[0067] Comparative Example 2 served as the control group for Example 5. In Example 2, the organic montmorillonite was replaced with polyethersulfone resin, while the remaining raw materials, raw material amounts, and preparation methods remained consistent with those in Example 5. Finally, a lightweight high-strength fiber composite material was obtained.

[0068] Comparative Example 3

[0069] Comparative Example 3 served as the control group for Example 5. The raw materials lignin and organo-modified montmorillonite in Example 2 were replaced with polyethersulfone resin, while the remaining raw materials, raw material amounts, and preparation methods remained consistent with those in Example 5. Finally, a lightweight high-strength fiber composite material was obtained.

[0070] Comparative Example 4

[0071] The difference between Comparative Example 4 and Example 5 lies in the preparation method of the lightweight high-strength fiber composite material. The raw materials and their amounts remain the same as in Example 5. The specific steps are as follows:

[0072] Weigh the raw materials according to the mass fraction, put the ternary matrix particles into the melting kettle and heat to 320°C until completely melted. Put the carbon fiber cloth into the melting kettle and impregnate it for 60 seconds under a pressure of 0.1 MPa to ensure that the molten matrix completely fills the fiber gaps and there are no air bubbles. Preheat the flat mold to 280°C, put the impregnated fiber cloth into the mold, apply a pressure of 10 MPa, keep it at 280°C for 20 minutes, and slowly cool it down to 80°C before demolding to finally obtain a high-strength fiber composite material.

[0073] Performance tests were conducted on Examples 4 to 6 and Comparative Examples 1 to 4. The performance test process is as follows, and the test results are shown in Table 1.

[0074] Tensile strength: Tested using a WAW-600E universal tensile testing machine (manufactured by Jinan Chenda Testing Machine Manufacturing Co., Ltd.) in accordance with GB / T6329-1996.

[0075] Overall density: In accordance with the provisions of GB / T1033.1-2008, the density was tested using a DH-300 solid material density tester (Xiamen Boshi Testing Equipment Co., Ltd.);

[0076] Fracture toughness: Tested using an electronic universal testing machine (Sterma Instruments Group) in accordance with GB / T21143-2014;

[0077] Shear strength: In accordance with the provisions of JCT773-2010, the interlaminar shear strength tester for fiber-reinforced plastics (Jinan Zongchi Measurement and Control Equipment Co., Ltd.) was used for testing;

[0078] Impact strength: Tested using a simply supported beam impact testing machine (Guangdong Hongtuo Instrument Technology Co., Ltd.) in accordance with GB / T1451-2005.

[0079] Table 1 Test Results

[0080] project Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Tensile strength / MPa 680 685 683 670 600 650 890 <![CDATA[Overall density / g / cm 3 > 1.36 1.35 1.34 1.50 1.32 1.41 1.60 <![CDATA[Fracture toughness / MPa·m 1 / 2 > 7.2 7.2 7.1 6.0 5.8 5.2 7.2 Shear strength / MPa 60 61 60 52 45 48 67 <![CDATA[Impact strength / kJ / m 2 > 81 82 81 65 67 58 65

[0081] Comparing the tensile strength data of Example 5 and Comparative Example 2, it can be seen that the present invention significantly improves the tensile strength of the composite material by introducing organic montmorillonite.

[0082] Comparing the overall density and impact strength data of Example 5 and Comparative Example 4, it can be concluded that the present invention significantly reduces the overall density of the composite material and improves its impact strength by introducing a porous structure through phase transformation.

[0083] Comparing the fracture toughness data of Example 5 and Comparative Example 3, it can be seen that the present invention significantly improves the fracture toughness of the composite material by introducing lignin and organo-modified montmorillonite.

[0084] Comparing the shear strength data of Example 5 and Comparative Example 2, it can be seen that the present invention significantly improves the shear strength of the composite material by introducing organic montmorillonite.

[0085] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0086] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lightweight, high-strength fiber composite material, characterized in that, By weight, it includes the following raw materials: 35-45 parts of T700 grade carbon fiber cloth; 55 to 65 parts of ternary matrix; The ternary matrix is ​​prepared by the following steps: T1. Dry lignin at 60°C for 8 hours, dry polyethersulfone resin at 120°C for 12 hours, then put lignin and polyethersulfone resin into a mixer and stir at 800 r / min for 10 minutes, then add organo-modified montmorillonite and continue stirring at 800 r / min for 15 minutes to obtain a premix. T2. Set the temperature of each section of the twin-screw extruder as follows: Zone 1 280℃, Zone 2 290℃, Zone 3 300℃, Zone 4 305℃, Zone 5 300℃, and Die 295℃. Add the premix to the hopper of the twin-screw extruder and melt-blend extrusion at a screw speed of 20r / min. After water cooling and stretching, the extrudate is cut into 3-5mm long particles. The particles are vacuum dried at 80℃ for 6 hours to obtain the ternary matrix. The ratio of polyethersulfone resin, lignin and organo-modified montmorillonite in T1 is 70-80g: 15-25g: 4-6g; The preparation method of the lightweight high-strength fiber composite material includes the following steps: S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, and stir at 80°C for 2 hours to form a homogeneous solution; S2. Immerse T700 grade carbon fiber cloth in a homogeneous solution to obtain impregnated carbon fiber cloth. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water for 10 minutes. After removal, dry it at 60°C for 4 hours to obtain a dried composite material. S3. React the dried composite material at 120°C for 20-40 minutes to obtain a lightweight high-strength fiber composite material.

2. The method for preparing a lightweight high-strength fiber composite material according to claim 1, characterized in that, Includes the following steps: S1. Weigh the above raw materials according to the mass fraction, dissolve the ternary matrix in N,N-dimethylacetamide, and stir at 80°C for 2 hours to form a homogeneous solution; S2. Immerse T700 grade carbon fiber cloth in a homogeneous solution to obtain impregnated carbon fiber cloth. Then, vertically immerse the impregnated carbon fiber cloth in 25°C deionized water for 10 minutes. After removal, dry it at 60°C for 4 hours to obtain a dried composite material. S3. React the dried composite material at 120°C for 20-40 minutes to obtain a lightweight high-strength fiber composite material.

3. The method for preparing a lightweight high-strength fiber composite material according to claim 2, characterized in that, The mass ratio of the ternary matrix to N,N-dimethylacetamide in S1 is 15:

85.

4. The method for preparing a lightweight high-strength fiber composite material according to claim 2, characterized in that, The mass of the deionized water in S2 is more than 10 times the mass of the impregnated carbon fiber cloth.