High performance fiber composite and method of making same

Abstract

The application belongs to the technical field of polymer materials, and particularly relates to a high-performance fiber composite material and a preparation method thereof. The preparation method of the high-performance fiber composite material comprises the following steps: adding pretreated aluminum oxide whiskers into a solvent, then adding pretreated carboxymethyl cellulose and gallic acid, and heating to reflux to obtain modified aluminum oxide whiskers; then mixing epoxy resin, the modified aluminum oxide whiskers, a curing agent and an accelerator uniformly to coat a film to obtain a resin adhesive film; and compounding the resin adhesive film and carbon fibers through hot pressing to obtain carbon fiber prepreg, and heating and curing the obtained prepreg to obtain the high-performance fiber composite material. The fiber composite material obtained by the application not only has high strength and rigidity, but also has excellent toughness, can effectively resist the impact of the external environment, has oxidation resistance and long-term stability, and has a wide application prospect in the fields of aerospace and new energy equipment.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, and particularly relates to a high-performance fiber composite material and its preparation method. Background Technology

[0002] High-performance fiber composites, with their superior properties such as light weight, high specific strength, and high temperature resistance, have become a hot research topic, finding wide applications in civilian fields such as wind power generation and automotive lightweighting, as well as military fields such as aerospace and missiles. In the wind power sector, with the increasing size of wind turbines, especially the growing demand for offshore wind power, fiber composites, due to their high strength and fatigue resistance, are widely used in the manufacture of key components such as the main beam cap and skin of wind turbine blades, effectively improving the stiffness and service life of the blades. In the new energy vehicle sector, carbon fiber composites help solve problems such as increased vehicle weight and poor driving range. In the aerospace field, compared with traditional materials such as aluminum alloys, these composites have advantages such as low density, high hardness, corrosion resistance, and stable properties. Their excellent creep resistance and high temperature resistance help them maintain their shape in the space environment, thus they are widely used in the manufacture of manned spacecraft and satellites. However, during service and maintenance, they are susceptible to low-impact impacts from the external environment, and the resulting dents are not easily visible to the naked eye but can significantly reduce compressive strength, posing potential dangers to flight safety.

[0003] Currently, some existing fiber composite materials still suffer from defects such as insufficient toughness, poor impact resistance, weak interfacial bonding between the reinforcement and the resin matrix, easy agglomeration of the reinforcement, and the need to improve long-term stability. For example, although alumina whiskers can improve the mechanical properties of carbon fiber composites as a reinforcement, their inherent brittleness makes it difficult for cracks to be effectively deflected at the interface between the whiskers and the matrix during crack propagation, resulting in poor toughening efficiency and affecting the overall performance of the composite material. Furthermore, the effect of adding alumina whiskers alone is limited.

[0004] To address the aforementioned shortcomings, developing a fiber composite material with high strength, high toughness, impact resistance, and long-term stability is of great significance for promoting the development of aerospace and civilian technology fields. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the primary objective of this invention is to provide a method for preparing high-performance fiber composite materials.

[0006] Another object of the present invention is to provide a high-performance fiber composite material.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a high-performance fiber composite material includes the following steps:

[0009] (1) Add hydroxymethyltriethoxysilane to the solvent, stir, add alumina whiskers, react, and obtain pretreated alumina whiskers;

[0010] (2) Take carboxymethyl cellulose, strong base and solubilizer, add them to water, stir and mix evenly, and freeze dry to obtain pretreated carboxymethyl cellulose;

[0011] (3) Take the pretreated alumina whiskers from step (1) and add them to the solvent, then add the pretreated carboxymethyl cellulose and gallic acid from step (2), heat and reflux to obtain modified alumina whiskers;

[0012] (4) Mix epoxy resin, modified alumina whiskers from step (3), curing agent and accelerator evenly and coat them into a film to obtain a resin film.

[0013] (5) The resin film from step (4) and carbon fiber are hot-pressed together to obtain carbon fiber prepreg;

[0014] (6) The carbon fiber prepreg from step (5) is heated and cured to obtain a high-performance fiber composite material.

[0015] Further, in step (1), the mass ratio of hydroxymethyltriethoxysilane, alumina whiskers and solvent is 1:(3-4):(40-50), and the solvent is anhydrous ethanol; the stirring time is 1-3h; the reaction temperature is 50-60℃ and the reaction time is 3-5h.

[0016] Further, in step (2), the mass ratio of carboxymethyl cellulose, strong alkali, co-solvent and water is (3-4):(6-7):(8-10):100; the strong alkali is potassium hydroxide and the co-solvent is urea; the freeze-drying temperature is -50℃ to -40℃ and the time is 8-12h.

[0017] Further, in step (3), the mass ratio of the pretreated alumina whiskers, pretreated carboxymethyl cellulose, gallic acid, and solvent is 1:(5-8):(6-9):(180-300); the solvent is anhydrous ethanol, and the reflux temperature is 78-85℃ for 3-5 hours.

[0018] Further, in step (4), the mass ratio of epoxy resin, modified alumina whiskers, curing agent and accelerator is (90-100): (8-15): (20-30): (0.1-0.5).

[0019] Further, in step (4), the curing agent is 4,4'-diaminodiphenyl sulfone, and the accelerator is dimethylimidazole.

[0020] Furthermore, in step (4), the coating temperature is 80-90℃, and the coating amount is 32-35g / m². 2 .

[0021] Furthermore, in step (5), the temperature of the hot-pressing composite is 85-95℃.

[0022] Further, in step (6), the heating and curing adopts an autoclave molding process, which includes the following steps: first, the temperature is raised from room temperature to 90-100℃ at a rate of 1-1.5℃ / min, and at this temperature, it is cured at 0.5-1MPa for 20-30min. Then, the temperature is raised to 130-150℃ at a rate of 1-1.5℃ / min, and cured at 1-2MPa for 0.5-1h. Finally, the temperature is raised to 180-190℃, and cured at 1-2MPa for 2-3h to obtain the product.

[0023] This invention provides a high-performance fiber composite material, which is prepared using the above-described preparation method.

[0024] The present invention has the following advantages over the prior art:

[0025] 1. This invention provides a high-performance fiber composite material that, through the synergistic effect of its components, exhibits excellent mechanical strength, toughness, impact resistance, and long-term stability. Specifically, the addition of modified alumina whiskers effectively improves the toughness of the fiber composite material. When subjected to impact, the composite material can absorb energy through yield deformation, thus dissipating fracture energy. Simultaneously, the numerous active functional groups such as hydroxyl and carboxyl groups on the surface of the modified alumina whiskers can form hydrogen bonds with the epoxy resin matrix, strengthening interfacial interactions and effectively improving the mechanical properties of the composite material. Furthermore, the introduced gallic acid possesses good antioxidant activity, contributing to improved long-term stability of the composite material.

[0026] 2. This invention first modifies alumina whiskers with hydroxymethyltriethoxysilane, successfully introducing a large number of alcohol hydroxyl active sites. Then, carboxymethyl cellulose is pretreated to make its structure more porous, significantly increasing its specific surface area and reactivity. Simultaneously, the pretreated carboxymethyl cellulose contains a large number of hydroxyl and carboxyl groups. Gallic acid, as a crosslinking agent, can undergo esterification reactions with the carboxyl groups on the pretreated carboxymethyl cellulose, and can also undergo etherification reactions with the alcohol methyl groups on the alumina whiskers; furthermore, the carboxyl groups of gallic acid can also undergo esterification reactions with the hydroxyl groups. Through these multiple crosslinking effects, a stable three-dimensional crosslinked network structure is ultimately formed between the alumina whiskers, carboxymethyl cellulose, and gallic acid, which helps to improve the mechanical properties and impact resistance of the composite material.

[0027] 3. The pretreated carboxymethyl cellulose of this invention not only possesses a large specific surface area and abundant polar functional groups (hydroxyl and carboxyl groups), but also exhibits good compatibility with epoxy resin, promoting uniform dispersion of modified alumina whiskers in the resin and preventing agglomeration, thereby ensuring the material's performance. Simultaneously, the excellent film-forming properties of carboxymethyl cellulose also contribute to improving the impregnation effect on carbon fibers.

[0028] 4. The present invention also provides a method for preparing the above-mentioned high-performance fiber composite material. This method is simple and efficient, which helps to realize industrial production and has wide applications in the field of preparing aerospace materials. Attached Figure Description

[0029] Figure 1 This is an electron microscope image of the modified alumina whiskers obtained in Example 1 of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed according to conventional experimental conditions or experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available.

[0031] The carbon fiber of this invention is 12K T800 industrial-grade unidirectional carbon fiber filament;

[0032] The epoxy resin of this invention is a bisphenol A type epoxy resin;

[0033] The alumina whiskers of this invention have a diameter of 260-500 nm and an aspect ratio of 60-88.

[0034] Example 1

[0035] A method for preparing a high-performance fiber composite material includes the following steps:

[0036] (1) Add hydroxymethyltriethoxysilane (CAS:162781-70-6) to anhydrous ethanol. The mass ratio of hydroxymethyltriethoxysilane to anhydrous ethanol is 1:45. Stir at room temperature for 2 hours. Add alumina whiskers. The amount of alumina whiskers added is 3.5 times the mass of hydroxymethyltriethoxysilane. React at 55°C for 4 hours. Cool naturally to room temperature and then filter. Wash the filtered solid material three times with anhydrous ethanol and three times with deionized water. Dry at 95°C for 6.5 hours to obtain pretreated alumina whiskers.

[0037] (2) Take carboxymethyl cellulose, potassium hydroxide and urea and add them to water. The mass ratio of carboxymethyl cellulose, potassium hydroxide, urea and water is 3.5:6.5:9:100. Stir and mix evenly, and freeze dry at -45℃ for 10h to obtain pretreated carboxymethyl cellulose.

[0038] (3) Take the pretreated alumina whiskers from step (1) and add them to anhydrous ethanol. Then add the pretreated carboxymethyl cellulose and gallic acid from step (2). The mass ratio of the pretreated alumina whiskers, carboxymethyl cellulose, gallic acid, and anhydrous ethanol is 1:7:8:240. Heat the mixture to reflux at 80°C for 4 hours, cool it naturally to room temperature, and then filter it. Wash the solid obtained by filtration with deionized water three times and dry it at 55°C for 4.5 hours to obtain modified alumina whiskers. The electron microscope image of the modified alumina whiskers is shown below. Figure 1 As shown.

[0039] (4) Weigh epoxy resin, modified alumina whiskers, curing agent (4,4'-diaminodiphenyl sulfone), and accelerator (dimethylimidazole) according to a mass ratio of 90:12:25:0.3; mix epoxy resin, modified alumina whiskers, 4,4'-diaminodiphenyl sulfone, and dimethylimidazole evenly, and coat them on a coating machine to form a resin film; wherein the coating temperature is 85℃ and the coating amount is 33g / m 2 ;

[0040] (5) The resin film from step (4) is laminated on a prepreg machine. The two resin films are placed on the upper and lower sides of the carbon fiber respectively. At 95°C, the carbon fiber is hot-pressed and laminated by a hot press roller to melt-impregnate the carbon fiber and obtain carbon fiber prepreg.

[0041] (6) Place the carbon fiber prepreg from step (5) in an autoclave and heat-cur it using an autoclave molding process: first, heat it from room temperature to 95°C at a rate of 1.2°C / min, and at this temperature, cure it at 0.8MPa for 20 min; then continue heating it to 140°C at a rate of 1.2°C / min, and cure it at 1.5MPa for 0.75 h; then heat it to 185°C and cure it at 1.5MPa for 2.5 h to obtain a high-performance fiber composite material.

[0042] This embodiment also provides a high-performance fiber composite material, which is prepared by the above-described method.

[0043] Example 2

[0044] A method for preparing a high-performance fiber composite material includes the following steps:

[0045] (1) Add hydroxymethyltriethoxysilane to anhydrous ethanol, wherein the mass ratio of hydroxymethyltriethoxysilane to anhydrous ethanol is 1:40, stir at room temperature for 1 h, add alumina whiskers, wherein the amount of alumina whiskers added is 3 times the mass of hydroxymethyltriethoxysilane, react at 50°C for 5 h, cool naturally to room temperature, and then filter. Wash the filtered solid material three times with anhydrous ethanol and three times with deionized water, and dry at 90°C for 7 h to obtain pretreated alumina whiskers.

[0046] (2) Take carboxymethyl cellulose, potassium hydroxide and urea and add them to water. The mass ratio of carboxymethyl cellulose, potassium hydroxide, urea and water is 3:6:8:100. Stir and mix evenly, and freeze dry at -40℃ for 12h to obtain pretreated carboxymethyl cellulose.

[0047] (3) Take the pretreated alumina whiskers from step (1) and add them to anhydrous ethanol. Then add the pretreated carboxymethyl cellulose and gallic acid from step (2). The mass ratio of the pretreated alumina whiskers, pretreated carboxymethyl cellulose, gallic acid and anhydrous ethanol is 1:5:6:180. Heat the mixture to reflux at 78°C for 3 hours, cool it naturally to room temperature, and then filter it. Wash the solid material obtained by filtration with deionized water three times and dry it at 50°C for 5 hours to obtain modified alumina whiskers.

[0048] (4) Weigh epoxy resin, modified alumina whiskers, curing agent (4,4'-diaminodiphenyl sulfone), and accelerator (dimethylimidazole) in a mass ratio of 90:8:20:0.1 respectively; mix epoxy resin, modified alumina whiskers, 4,4'-diaminodiphenyl sulfone, and dimethylimidazole evenly, and coat them on a coating machine to form a resin film; wherein the coating temperature is 80℃ and the coating amount is 32g / m 2 ;

[0049] (5) The resin film from step (4) is laminated on a prepreg machine. The two resin films are placed on the upper and lower sides of the carbon fiber respectively. At 90°C, the carbon fiber is hot-pressed and laminated by a hot press roller to melt-impregnate the carbon fiber and obtain carbon fiber prepreg.

[0050] (6) Place the carbon fiber prepreg from step (5) in an autoclave and heat and cure it using an autoclave molding process: first, heat it from room temperature to 90°C at a rate of 1°C / min, and cure it at 0.5MPa for 20 minutes at this temperature; then heat it to 130°C at a rate of 1°C / min, and cure it at 1MPa for 1 hour; then heat it to 180°C and cure it at 1MPa for 3 hours to obtain a high-performance fiber composite material.

[0051] This embodiment also provides a high-performance fiber composite material, which is prepared by the above-described method.

[0052] Example 3

[0053] A method for preparing a high-performance fiber composite material includes the following steps:

[0054] (1) Add hydroxymethyltriethoxysilane to anhydrous ethanol, wherein the mass ratio of hydroxymethyltriethoxysilane to anhydrous ethanol is 1:50, stir at room temperature for 3 hours, add alumina whiskers, wherein the amount of alumina whiskers added is 4 times the mass of hydroxymethyltriethoxysilane, react at 60°C for 3 hours, cool naturally to room temperature, and then filter. Wash the filtered solid material three times with anhydrous ethanol and three times with deionized water, and dry at 100°C for 6 hours to obtain pretreated alumina whiskers.

[0055] (2) Take carboxymethyl cellulose, potassium hydroxide and urea and add them to water. The mass ratio of carboxymethyl cellulose, potassium hydroxide, urea and water is 4:7:10:100. Stir and mix evenly, and freeze dry at -50℃ for 8 hours to obtain pretreated carboxymethyl cellulose.

[0056] (3) Take the pretreated alumina whiskers from step (1) and add them to anhydrous ethanol. Then add the pretreated carboxymethyl cellulose and gallic acid from step (2). The mass ratio of the pretreated alumina whiskers, pretreated carboxymethyl cellulose, gallic acid and anhydrous ethanol is 1:8:9:300. Heat to reflux at 85°C for 5 hours, cool naturally to room temperature, and then filter. Wash the solid material obtained by filtration with deionized water three times and dry it at 60°C for 4 hours to obtain modified alumina whiskers.

[0057] (4) Weigh epoxy resin, modified alumina whiskers, curing agent (4,4'-diaminodiphenyl sulfone), and accelerator (dimethylimidazole) according to a mass ratio of 100:15:30:0.5; mix epoxy resin, modified alumina whiskers, 4,4'-diaminodiphenyl sulfone, and dimethylimidazole evenly, and coat them on a coating machine to form a resin film; wherein the coating temperature is 90℃ and the coating amount is 35g / m 2 ;

[0058] (5) The resin film from step (4) is laminated on a prepreg machine. The two resin films are placed on the upper and lower sides of the carbon fiber respectively. At 100°C, the carbon fiber is hot-pressed and laminated by a hot press roller to melt-impregnate the carbon fiber and obtain carbon fiber prepreg.

[0059] (6) Place the carbon fiber prepreg from step (5) in an autoclave and heat-cur it using an autoclave molding process: first, heat it from room temperature to 100°C at a rate of 1.5°C / min, and at this temperature, cure it at 1 MPa for 30 min; then continue heating it to 150°C at a rate of 1.5°C / min, and cure it at 2 MPa for 1 h; then heat it to 190°C and cure it at 2 MPa for 2 h to obtain a high-performance fiber composite material.

[0060] This embodiment also provides a high-performance fiber composite material, which is prepared by the above-described method.

[0061] Comparative Example 1

[0062] Comparative Example 1 is basically the same as Example 1, except that steps (1) to (3) are omitted, and the modified alumina whiskers in step (4) are replaced with alumina whiskers. Otherwise, it is the same as Example 1.

[0063] Comparative Example 2

[0064] Comparative Example 2 is basically the same as Example 1, except that steps (1) to (3) are omitted, and the modified alumina whiskers in step (4) are replaced with alumina whiskers, carboxymethyl cellulose and gallic acid (the amount of alumina whiskers, carboxymethyl cellulose and gallic acid is controlled to be the same as in Example 1), and the rest is consistent with Example 1.

[0065] Test case

[0066] The properties of the composite materials obtained in Examples 1-3 and Comparative Examples 1-2 of this invention were tested using the following methods:

[0067] (1) The bending properties of high-performance fiber composite materials were tested in accordance with the standard ASTM D7264;

[0068] (2) The compressive strength of high-performance fiber composite materials was tested in accordance with the standard ASTM D6641;

[0069] (3) Test the compressive strength of high-performance fiber composite materials after impact according to standard ASTM D7137;

[0070] (4) Its type II interlaminar fracture toughness was tested with reference to the standard ASTM D7905 / D7905M.

[0071] The test results are all recorded in Table 1.

[0072] Table 1

[0073]

[0074] As shown in Table 1, the composite materials obtained in Examples 1-3 of this invention exhibit superior flexural strength, compressive strength, post-impact compressive strength, and type II interlaminar fracture toughness compared to Comparative Examples 1 and 2. Compared to Example 1, Comparative Example 1 replaced the modified alumina whiskers with alumina whiskers, and Comparative Example 2 replaced the modified alumina whiskers with alumina whiskers, carboxymethyl cellulose, and gallic acid. The overall performance of Comparative Examples 1 and 2 was inferior to that of Example 1. These results demonstrate that the modified alumina of this invention can effectively improve the toughness, mechanical properties, and post-impact compressive strength of fiber composite materials, thereby contributing to improved long-term stability. The pretreated carboxymethyl cellulose in this invention can work synergistically with the modified alumina whiskers to enhance the toughness and mechanical properties of the composite material. Furthermore, the pretreated carboxymethyl cellulose exhibits excellent compatibility with components such as the epoxy resin matrix, enabling uniform dispersion of the modified alumina whiskers in the resin and improving the impregnation effect on carbon fibers, thus enhancing the overall performance of the fiber composite material and making it suitable for preparing composite materials for aerospace and other applications.

[0075] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a high-performance fiber composite material, characterized in that, Includes the following steps: (1) Add hydroxymethyltriethoxysilane to the solvent, stir, add alumina whiskers, react, and obtain pretreated alumina whiskers; (2) Take carboxymethyl cellulose, strong base and solubilizer, add them to water, stir and mix evenly, and freeze dry to obtain pretreated carboxymethyl cellulose; (3) Take the pretreated alumina whiskers from step (1) and add them to the solvent, then add the pretreated carboxymethyl cellulose and gallic acid from step (2), heat and reflux to obtain modified alumina whiskers; (4) Mix epoxy resin, modified alumina whiskers from step (3), curing agent and accelerator evenly, and coat them to form a resin film. (5) The resin film from step (4) and carbon fiber are hot-pressed together to obtain carbon fiber prepreg; (6) The carbon fiber prepreg from step (5) is heated and cured to obtain a high-performance fiber composite material.

2. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (1), the mass ratio of hydroxymethyltriethoxysilane, alumina whiskers, and solvent is 1:(3-4):(40-50), and the solvent is anhydrous ethanol; the stirring time is 1-3 h; the reaction temperature is 50-60 °C, and the reaction time is 3-5 h.

3. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (2), the mass ratio of carboxymethyl cellulose, strong alkali, co-solvent and water is (3-4):(6-7):(8-10):100; the strong alkali is potassium hydroxide and the co-solvent is urea; the freeze-drying temperature is -50℃ to -40℃ and the time is 8-12h.

4. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (3), the mass ratio of the pretreated alumina whiskers, pretreated carboxymethyl cellulose, gallic acid, and solvent is 1:(5-8):(6-9):(180-300); the solvent is anhydrous ethanol, the reflux temperature is 78-85℃, and the time is 3-5h.

5. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (4), the mass ratio of epoxy resin, modified alumina whiskers, curing agent and accelerator is (90-100): (8-15): (20-30): (0.1-0.5).

6. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (4), the curing agent is 4,4'-diaminodiphenyl sulfone, and the accelerator is dimethylimidazole.

7. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (4), the coating temperature is 80-90℃, and the coating amount is 32-35g / m². 2 .

8. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (5), the temperature of the hot-pressing composite is 85-95℃.

9. The method for preparing the high-performance fiber composite material according to claim 1, characterized in that, In step (6), the heating and curing process adopts an autoclave molding process, which includes the following steps: first, heating from room temperature to 90-100℃ at a heating rate of 1-1.5℃ / min, and curing at 0.5-1MPa for 20-30min at this temperature; then heating to 130-150℃ at a heating rate of 1-1.5℃ / min, and curing at 1-2MPa for 0.5-1h. Then heat to 180-190℃ and cure at 1-2MPa for 2-3 hours to obtain the product.

10. A high-performance fiber composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

Images