Modified carbon fiber material and preparation method thereof

Abstract

The invention provides a modified carbon fiber material and a preparation method thereof, and the preparation method comprises the following steps: S1, dissolving a polyurethane reinforcing aid in absolute ethyl alcohol to obtain a first mixed solution; s2, pouring the first mixed solution into EL2 epoxy laminated resin, stirring to obtain a second mixed solution, heating the second mixed solution, and airing for later use; s3, uniformly stirring the GC polyester gel coat, coating the mold with the GC polyester gel coat, and standing until the surface is not sticky; s4, uniformly coating the second mixed solution on the surface of the GC polyester gel coat; s5, covering the GC polyester gel coat coated with the second mixed solution with a twill carbon fiber material, and brushing a layer of modified EL epoxy resin on the twill carbon fiber material; s6, repeating the step S5 for at least one time; s7, extruding the mold to discharge bubbles, and brushing off redundant modified EL epoxy resin by using a brush; and S8, standing and demolding to obtain the modified carbon fiber material. The modified carbon fiber material has strain rate sensitivity, and meanwhile, the brittleness of a traditional carbon fiber material can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of carbon fiber materials, and in particular to a modified carbon fiber material and a preparation method thereof. Background Art

[0002] Carbon fiber is an inorganic polymer fiber with a carbon content of more than 90%. Due to its high carbon content, it can be used to manufacture composite materials with high temperature resistance. The application fields of high temperature resistant materials include aviation, aerospace, military, batteries, environmental protection, automobiles and construction. Carbon fiber consists of major processes such as raw silk, pre-oxidation and carbonization, plus several small processes under each major process. Twill carbon fiber is formed by steaming the pre-oxidized polyacrylonitrile yarn, and then through the processes of splitting, feeding, changing direction, pressurizing and heating, and dipping. The surface of the carbon fiber sheet has wool yarn or thorn-shaped pit-shaped small holes, and a layer of resin is attached. It can not only increase the adhesion of carbon fiber, but also prevent the sheet from wrinkling and improve exhaust during molding.

[0003] However, the obvious brittleness and insufficient toughness of carbon fiber materials will limit their application in some areas. In addition, if carbon fiber materials are strain rate sensitive, they will be more widely used in many fields such as biomedicine.

[0004] In view of this, the present application proposes a modified carbon fiber material and a preparation method thereof, which can obtain a carbon fiber material with strain rate sensitivity and improve the brittleness of the carbon fiber material. Summary of the invention

[0005] In order to solve the problems of obvious brittleness and insufficient toughness of existing carbon fiber materials, the present application provides a modified carbon fiber material and a preparation method thereof to solve the above-mentioned technical defects.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a modified carbon fiber material, comprising the following steps:

[0008] S1, dissolving the polyurethane reinforcing agent in anhydrous ethanol to obtain a first mixed solution;

[0009] S2, pouring the first mixed solution into EL2 epoxy laminating resin, stirring to obtain a second mixed solution, heating the second mixed solution, and then cooling it for later use;

[0010] S3, after stirring the GC polyester gel coat evenly, apply it on the mold and let it stand until the surface is no longer sticky;

[0011] S4, evenly coating the second mixed solution on the surface of the GC polyester gel coat;

[0012] S5, covering the twill carbon fiber material on the GC polyester gel coat coated with the second mixed solution, and brushing a layer of modified EL epoxy resin thereon;

[0013] S6, repeat step S5 at least once;

[0014] S7, squeeze the mold to expel air bubbles, and brush off excess modified EL epoxy resin with a brush;

[0015] S8. After standing still, demoulding is performed to obtain the modified carbon fiber material.

[0016] Preferably, in step S1, the mass ratio of the polyurethane reinforcing agent to anhydrous ethanol is 1:1.

[0017] Preferably, in step S2, the mass ratio of the first mixed solution to the EL2 epoxy laminating resin is 1:9.

[0018] Preferably, in step S2, the second mixed solution is heated to 80°C-100°C under stirring, and then cooled for standby use.

[0019] Preferably, in step S3, the GC polyester gel coat is evenly stirred and then coated on the mold with a thickness of 0.3-0.4 mm, and allowed to stand until the surface is no longer sticky.

[0020] Preferably, in step S3, the GC polyester gel coat is evenly stirred and then coated on the mold, and left for 1 hour until the surface is no longer sticky.

[0021] Preferably, in step S8, the modified carbon fiber material can be obtained by demoulding after standing for at least 24 hours.

[0022] In a second aspect, the present invention provides a modified carbon fiber material, which is prepared according to any of the above-mentioned methods for preparing the modified carbon fiber material.

[0023] Compared with the prior art, the beneficial results of the present invention are:

[0024] (1) Significantly improve the performance of carbon fiber materials: By using a mixed modification of polyurethane reinforcing additives and EL2 epoxy laminating resin, the brittleness of traditional carbon fiber materials is effectively improved and their toughness is enhanced. When subjected to external forces, this modified carbon fiber material can show better impact resistance and durability, thereby broadening its application areas, especially in situations where high-toughness materials are required.

[0025] (2) Improved strain rate sensitivity: After the modification treatment of the present invention, the sensitivity of the carbon fiber material to strain rate is significantly improved. This means that in fields such as biomedicine and sports equipment that require materials to respond quickly to external mechanical stimuli, the modified carbon fiber material of the present invention can provide better comfort and performance.

[0026] (3) Simplify the preparation process and reduce costs: The preparation method of the present invention is relatively simple and does not require complex equipment and harsh conditions of high temperature and high pressure. Through reasonable proportioning and process control, the production cost can be effectively reduced and the production efficiency can be improved while ensuring the modification effect. This is of great significance for promoting the widespread application of carbon fiber materials.

[0027] (4) Optimize coating process and improve material quality: During the preparation process, the uniformity and consistency of the modified carbon fiber material are ensured by precisely controlling the coating thickness and standing time of the GC polyester gel coat, as well as the coating and repeated brushing times of the modified EL epoxy resin. This not only improves the quality stability of the material, but also helps reduce waste and defective rates during the production process.

[0028] (5) Environmentally friendly, efficient and easy to promote: The raw materials used in the preparation method of the present invention are all environmentally friendly materials, and the entire preparation process has no harmful emissions, which meets the requirements of modern industry for environmental protection and sustainable development. At the same time, due to the simple preparation process and low cost, the modified carbon fiber material of the present invention is easier to promote and apply. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 It is a flow chart of a method for preparing a modified carbon fiber material according to a specific embodiment of the present application. DETAILED DESCRIPTION

[0031] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0032] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] Figure 1 A flow chart of a method for preparing a modified carbon fiber material according to a specific embodiment of the present application is shown, as shown in FIG. Figure 1 As shown, the present invention provides a method for preparing a modified carbon fiber material, comprising the following steps:

[0034] S1, dissolving the polyurethane reinforcing agent in anhydrous ethanol to obtain a first mixed solution;

[0035] S2, pouring the first mixed solution into EL2 epoxy laminating resin, stirring to obtain a second mixed solution, heating the second mixed solution, and then cooling it for later use;

[0036] S3, after stirring the GC polyester gel coat evenly, apply it on the mold and let it stand until the surface is no longer sticky;

[0037] S4, evenly coating the second mixed solution on the surface of the GC polyester gel coat;

[0038] S5, covering the twill carbon fiber material on the GC polyester gel coat coated with the second mixed solution, and brushing a layer of modified EL epoxy resin thereon;

[0039] S6, repeat step S5 at least once;

[0040] S7, squeeze the mold to expel air bubbles, and brush off excess modified EL epoxy resin with a brush;

[0041] S8. After standing still, demoulding is performed to obtain the modified carbon fiber material.

[0042] Embodiment 1:

[0043] Dissolve 5g of polyurethane reinforcing agent in 5g of anhydrous ethanol, stir evenly to obtain a first mixed solution, pour the first mixed solution into 90g of EL2 epoxy laminating resin to obtain a second mixed solution. Under stirring, heat the second mixed solution to 80°C-100°C, cool and set aside. Preferably, heat the second mixed solution to 80°C. It should be understood that 80°C is the temperature at which alcohol and water begin to azeotropically form. If the temperature is less than 80°C, the alcohol and water will not evaporate completely; and if the temperature is greater than 100 degrees, resources will be wasted and other compounds may be damaged.

[0044] Preparation of carbon fiber materials: prepare a suitable mold, stir the GC polyester gel coat evenly, and apply it on the mold with a thickness of 0.3-0.4mm. If the thickness is less than 0.3mm or the thickness is greater than 0.4mm, the bonding strength will be low. Leave it for 2 hours until the surface is not sticky. After repeated experiments, it is known that if the placement time is less than 2 hours, it is too sticky, and if the placement time is more than 3 hours, the viscosity is not enough.

[0045] Apply the modified EL epoxy resin evenly on the dried GC polyester gel coat surface with a thickness of 0.3-0.4mm. If the thickness is less than 0.3mm or greater than 0.4mm, the bonding strength is low.

[0046] Cover a piece of twill carbon fiber with GC polyester gel coat coated with EL2 epoxy resin, and then apply a layer of modified EL2 epoxy resin. Repeat this step.

[0047] Gently squeeze the entire surface or part of the mold coated with EL epoxy resin and twill carbon fiber to expel bubbles, and carefully brush off excess resin with a brush. Specifically, you can use your palm, fingers or special tools (such as scrapers, rollers, etc., depending on the actual operation) to flatten or roll the mold surface. It is important to ensure that the squeezing force is moderate, enough to expel bubbles, but also to avoid damaging the carbon fiber material or destroying its structure.

[0048] Leave it overnight (i.e. 24 hours or more), and then carefully remove the carbon fiber material from the mold. It should be understood that if it is less than 24 hours, the viscosity is high and it is difficult to demold; if it is more than 24 hours, there will be no effect.

[0049] Embodiment 2:

[0050] (1) The polyurethane reinforcing agent is dissolved in anhydrous ethanol, and the mass ratio of the polyurethane reinforcing agent to the anhydrous ethanol is 1:1.

[0051] (2) Pour the solution into EL2 epoxy laminating resin, the mass ratio of solution to epoxy resin is 1:9. Heat the mixture to 80 degrees Celsius while stirring, and then let it cool for later use.

[0052] (3) Prepare a suitable mold, mix the GC polyester gel coat evenly, apply it on the mold with a thickness of 0.3-0.4mm, and leave it for 1 hour until the surface is no longer sticky.

[0053] (4) Evenly apply the modified EL2 epoxy resin on the surface of the dried GC polyester gel coat.

[0054] (5) Place a twill carbon fiber on the EL2 epoxy laminating resin film at a fiber angle of 0°, then spread the EL2 epoxy laminating resin evenly with a brush, and apply a second layer of modified EL2 epoxy laminating resin at a fiber angle of 90°.

[0055] (6) Repeat step (5).

[0056] (7) Apply the third layer of modified EL2 epoxy laminating resin in the direction of fiber angle 0°

[0057] (8) Repeat step (5).

[0058] (9) Apply the fourth layer of modified EL2 epoxy laminating resin at a fiber angle of 90°

[0059] (10) Gently squeeze out the bubbles and carefully brush off the excess resin with a brush.

[0060] (11) The modified carbon fiber material is placed for 24 hours or more and then demolded to obtain the modified carbon fiber material.

[0061] In a specific embodiment, the model of the twill carbon fiber material is Japan Toray T800.

[0062] Alternatively, the preparation method of the twill carbon fiber material is:

[0063] A sizing solution is prepared by mixing polyacrylonitrile pre-oxidized yarn with an average single yarn diameter of 7 microns and epoxy resin solution with a viscosity of 4500 mPa·s in a ratio of 10:3, and the pre-oxidized yarn is impregnated to make the epoxy resin content of the surface layer of the pre-oxidized yarn 16%. The pre-oxidized yarn is placed in a drying drum with a heat medium temperature of 180 degrees Celsius and heated to obtain carbon fiber yarn with an epoxy resin content of 16%;

[0064] Four layers of carbon fiber filaments impregnated with epoxy resin having a content of 16% were subjected to four times of dipping, drying, cooling and winding to obtain a twill carbon fiber material with a single yarn diameter of 7 microns and an epoxy resin content of 16%.

[0065] The present invention also provides a modified carbon fiber material, which is prepared according to any of the above-mentioned methods for preparing the modified carbon fiber material.

[0066] The present invention modifies the carbon fiber material in view of the fact that the carbon fiber material in the prior art has no strain sensitivity and is brittle. The obtained carbon fiber material has strain sensitivity and becomes hard at the moment of being subjected to external force. When the external force is applied slowly, elastic deformation will occur. And to a certain extent, the toughness of the carbon fiber material is improved. Moreover, the equipment used in the present invention is simple, does not require harsh conditions of high temperature and high pressure, and is environmentally friendly and efficient.

[0067] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other to form a technical solution.

Claims

1. A method for preparing a modified carbon fiber material, characterized in that: The following steps are involved: S1, dissolving the polyurethane reinforcing agent in anhydrous ethanol to obtain a first mixed solution; S2, pouring the first mixed solution into EL2 epoxy laminating resin, stirring to obtain a second mixed solution, heating the second mixed solution, and then cooling it for later use; S3, after stirring the GC polyester gel coat evenly, apply it on the mold and let it stand until the surface is no longer sticky; S4, uniformly coating the second mixed solution on the surface of the GC polyester gel coat; S5, covering the twill carbon fiber material on the GC polyester gel coat coated with the second mixed solution, and brushing another layer of the modified EL epoxy resin thereon; S6, repeat step S5 at least once; S7, squeezing the mold to expel air bubbles, and brushing off excess modified EL epoxy resin with a brush; S8. After standing still, demoulding is performed to obtain the modified carbon fiber material.

2. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S1, the mass ratio of the polyurethane reinforcing agent to the anhydrous ethanol is 1:

1.

3. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S2, the mass ratio of the first mixed solution to the EL2 epoxy laminating resin is 1:

9.

4. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S2, the second mixed solution is heated to 80°C-100°C under stirring, and then cooled for later use.

5. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S3, the GC polyester gel coat is evenly stirred and coated on the mold with a thickness of 0.3-0.4 mm, and allowed to stand until the surface is no longer sticky.

6. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S3, the GC polyester gel coat is evenly stirred and then coated on the mold, and left for 1 hour until the surface is no longer sticky.

7. The method for preparing the modified carbon fiber material according to claim 1, characterized in that: In step S8, the modified carbon fiber material can be obtained by demoulding after standing for at least 24 hours.

8. A modified carbon fiber material, characterized in that: The modified carbon fiber material is prepared according to the method for preparing the modified carbon fiber material as described in any one of claims 1 to 7.

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