Carbon fiber reinforced modified resin material and preparation method thereof

Abstract

The invention discloses a carbon fiber reinforced modified resin material and a preparation method thereof, and belongs to the technical field of high-molecular compound composition.The preparation method comprises the steps that 40-60 parts of acidified carbon fibers, 8-12 parts of silane coupling agent modified graphene oxide, 10-20 parts of polyethylene glycol and 3-8 parts of alkylphenol polyoxyethylene ether are ultrasonically mixed to be uniform with acetone as a solvent, and a mixture I is obtained; mixing 100 parts of epoxy resin and 30-50 parts of a curing agent, heating and stirring until the mixture is melted to obtain a mixture II; the mixture I and the mixture II are placed in a vacuum drying oven to be mixed and stirred, the obtained product is placed at the room temperature and then subjected to heating curing treatment, and the carbon fiber reinforced modified resin material is obtained, so that the interface bonding strength of the composite material is remarkably improved by optimizing the formula, and the composite material has excellent mechanical properties; the composite material has a wide application prospect in the fields of aerospace, automobile manufacturing, electronics and other high-performance composite material requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer compound compositions, and particularly relates to a carbon fiber reinforced modified resin material and a preparation method thereof. Background Art

[0002] Carbon fiber reinforced modified resin refers to a composite material with resin as the matrix material and carbon fiber as the reinforcing material. With the progress of technology and the acceleration of the industrialization process, especially in the fields of automotive lightweighting, aerospace technology innovation, and military equipment upgrading, the requirements for the strength, stiffness, heat resistance, and lightweight of materials are becoming increasingly strict. Carbon fiber resin matrix composites are widely used in main load-bearing structures and precision support components in the automotive, aerospace, and military fields due to their excellent properties such as high specific strength, high specific modulus, and small thermal expansion coefficient.

[0003] However, although carbon fiber reinforced modified resin composites have many advantages, they still face a series of technical defects in current research and applications, which hinder their wider application and performance optimization.

[0004] Firstly, thermosetting resin, as a commonly used matrix material, although exhibits good heat resistance and dimensional stability due to its highly cross-linked network structure, this structure also brings inherent brittleness, resulting in poor fracture toughness of the material. This characteristic limits the application of the composite material in extreme environments such as high impact and high load, especially in the aerospace and military fields that need to withstand complex stress states.

[0005] In addition, thermosetting resin matrix requires a high temperature during the curing process, which not only increases the processing cost and energy consumption, but also may cause thermal damage to carbon fibers. At the same time, the compatibility of thermosetting resin with other matrix materials is poor, which limits the application of the composite material in multi-material systems. Moreover, the high viscosity of the resin at room temperature during processing results in poor fluidity, making it difficult to fully infiltrate the voids between carbon fiber bundles, affecting the denseness and uniformity of the composite material, and thus reducing its mechanical properties.

[0006] Finally, the performance of the interface layer between carbon fiber and resin matrix is a key factor affecting the overall performance of the composite material. Due to the inert surface and lack of polar functional groups of carbon fibers, the bonding force between unmodified carbon fibers and resin matrix is weak, and the interface layer is fragile. This not only reduces the mechanical properties and durability of the composite material, but also may cause debonding or delamination at the interface during the stress process, further weakening the overall performance of the material.

[0007] In summary, although carbon fiber-reinforced modified resin composites have great potential in improving material properties and expanding application fields, problems such as the high brittleness and poor compatibility of the matrix resin, the vulnerability of the interface layer, and the poor bonding between the resin and carbon fiber still limit the practical application of carbon fiber-reinforced modified resin composites in various high-precision fields. Summary of the Invention

[0008] The purpose of this section is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this section, the abstract, and the title, but such simplifications or omissions shall not be used to limit the scope of the present invention.

[0009] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0010] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a preparation method for a carbon fiber-reinforced modified resin material.

[0011] To solve the above technical problems, the present invention provides the following technical solutions: including,

[0012] 40 - 60 parts of acidified carbon fiber, 8 - 12 parts of graphene oxide modified with silane coupling agent, 10 - 20 parts of polyethylene glycol, and 3 - 8 parts of alkylphenol polyoxyethylene ether are ultrasonically mixed evenly with acetone as the solvent to obtain mixture I;

[0013] 100 parts of epoxy resin are mixed with 30 - 50 parts of curing agent, heated and stirred until melted to obtain mixture II;

[0014] Further, the heating and stirring temperature in this step is 55 - 75 °C, and the heating and stirring time is 10 - 20 min. It should be noted that after the heating reaction in this step, due to the short curing time, the obtained mixture II is not completely cured, but forms a uniform mixture to participate in the next reaction;

[0015] Mixture I and mixture II are placed in a vacuum oven for mixing and stirring, and the obtained product is cured by heating after standing at room temperature, thus obtaining the carbon fiber-reinforced modified resin material.

[0016] As a preferred embodiment of the preparation method for the carbon fiber-reinforced modified resin material of the present invention, wherein: the preparation method of the acidified carbon fiber is,

[0017] Carbon fiber and acetone are ultrasonically mixed evenly according to a mass-to-volume ratio of 1 g:10 - 15 ml, placed in a three-necked flask, refluxed at 60 - 70 °C for 24 - 48 h, after the reflux ends, the upper clear liquid is removed by centrifugation, and then vacuum dried;

[0018] The obtained product is acidified with the mixed strong acid at a mass-to-volume ratio of 1 g: 10 - 15 ml and at 70 - 80 °C for 2 - 3 h. After the reaction, the supernatant is removed by centrifugation, deionized water and absolute ethanol are added and shaken, and the washing is repeated until the pH of the solution is alkaline, and then vacuum drying is carried out to obtain acidified carbon fibers.

[0019] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the mixed strong acid is obtained by mixing concentrated sulfuric acid and concentrated nitric acid at a volume ratio of 1 - 3: 1 - 3.

[0020] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the preparation method of the graphene oxide modified by the silane coupling agent is as follows.

[0021] γ-aminopropyltriethoxysilane and water are mixed at a volume ratio of 1 - 3: 9, and ultrasonic treatment is carried out for 30 - 60 min to obtain a silane coupling agent hydrolysis solution.

[0022] Graphene oxide powder and a dispersant are added thereto, and ultrasonic treatment is continued for 30 min. After being uniformly dispersed, the temperature is raised to 80 - 90 °C and the reaction is carried out for 6 - 8 hours. The product is filtered and dried to obtain graphene oxide modified by the silane coupling agent.

[0023] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the mass fraction of the graphene oxide in the silane coupling agent hydrolysis solution is 15 - 25%, and the mass ratio of the graphene oxide to the dispersant is 1: 0.1 - 0.3.

[0024] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the mixture II is obtained by heating and stirring until melted, wherein the temperature of the heating and stirring is 55 - 75 °C, and the time of the heating and stirring is 10 - 20 min.

[0025] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the mixture I and the mixture II are placed in a vacuum oven and mixed and stirred, wherein the temperature of the mixing and stirring is 55 - 60 °C, and the time is 2 - 4 h.

[0026] As a preferred embodiment of the preparation method of the carbon fiber-reinforced modified resin material described in the present invention, wherein: the obtained product is placed at room temperature and then subjected to heat curing treatment, wherein the time of placing at room temperature is 10 - 14 h.

[0027] As a preferred embodiment of the preparation method of the carbon fiber reinforced modified resin material described in the present invention, wherein: the temperature of the curing treatment is 70-90 °C, and the time is 2-4 h.

[0028] Advantages of the present invention:

[0029] By acidifying the carbon fiber, the surface properties of the carbon fiber are improved, and the number of surface functional groups is increased, thereby enhancing the interfacial bonding force between the carbon fiber and the resin matrix;

[0030] By modifying graphene oxide with a silane coupling agent, the compatibility between graphene oxide and the resin matrix is improved, and the interfacial bonding force is enhanced;

[0031] Introducing the high molecular polymer polyethylene glycol as a bridging molecule can connect the modified GO and the epoxy resin matrix. The hydroxyl groups of PEG form chemical bonding with the silyl functional groups on the surface of the modified GO and the epoxy functional groups in the epoxy resin, thereby enhancing the interfacial bonding force between GO and the resin matrix

[0032] Introducing the non-ionic surfactant alkylphenol polyoxyethylene ether, which has both a dispersing effect and a certain adhesive property, can act as a plasticizer in the resin, increasing the fluidity of the resin, and also helping to improve the dispersion of other fillers (such as carbon fiber, graphene oxide, etc.) in the resin;

[0033] By deeply analyzing the interaction mechanism between the components and reasonably designing the formula, the present invention significantly improves the interfacial bonding force of the carbon fiber reinforced modified resin composite material, and further improves the overall mechanical properties of the composite material, having broad application prospects in the fields of high-performance composite materials such as aerospace, automotive manufacturing, and electronic appliances. Specific embodiments

[0034] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the embodiments of the specification.

[0035] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar promotions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0036] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" appearing in different places in this specification does not all refer to the same embodiment, nor is it a separate or alternative embodiment that mutually excludes other embodiments.

[0037] In the present invention, the carbon fiber used is T700 carbon fiber, the epoxy resin used is bisphenol A epoxy resin, the polyethylene glycol used is polyethylene glycol 6000, and the alkylphenol polyoxyethylene ether used is alkylphenol polyoxyethylene ether TX-10. All are purchased from Jiangsu Santuo New Materials Co., Ltd. The remaining raw materials are also commonly commercially available in this field without special instructions.

[0038] In the performance test of the present invention, the tensile strength was measured with reference to the standard (GB / T3354-1999); the impact toughness was measured with reference to the standard GBT1451-2005.

[0039] Example 1

[0040] This example provides a preparation method of a carbon fiber-reinforced modified resin material. Specifically:

[0041] 1) 1 g of carbon fiber was ultrasonically mixed evenly with 10 mL of acetone and then placed in a three-necked flask. It was refluxed at 70 °C for 48 h. After the reflux ended, it was centrifuged for 0.5 h. After removing the supernatant, it was dried in vacuum. The obtained product was acidified and reacted with 10 mL of a mixed strong acid solution prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1 at 80 °C for 3 h. After the reaction ended, the supernatant was removed by centrifugation, deionized water and absolute ethanol were added and shaken, and the washing was repeated until the solution pH = 7, and then it was dried in vacuum to obtain acidified carbon fiber;

[0042] 2) γ-aminopropyltriethoxysilane and water were mixed in a volume ratio of 1:9 and ultrasonically treated for 30 min to obtain a silane coupling agent hydrolysis solution. Graphene oxide powder and calcium lignosulfonate (dispersant) were added thereto and ultrasonically treated for another 30 min. Among them, the mass fraction of graphene oxide in the silane coupling agent hydrolysis solution was 20%, and the mass ratio of graphene oxide to calcium lignosulfonate was 1:0.1. After being dispersed evenly, the temperature was raised to 90 °C and reacted for 6 hours. The product was filtered and dried to obtain silane coupling agent-modified graphene oxide;

[0043] 3) 50 parts of acidified carbon fiber, 10 parts of silane coupling agent-modified graphene oxide, 15 parts of polyethylene glycol, and 5 parts of alkylphenol polyoxyethylene ether were ultrasonically mixed evenly with acetone as the solvent to obtain mixture I;

[0044] 100 parts of epoxy resin and 40 parts of triethylenetetramine were mixed and heated and stirred at 60 °C for 10 min to obtain mixture II;

[0045] Mixture I and mixture II were placed in a 55 °C vacuum oven and mixed and stirred for 3 h. The obtained product was left at room temperature for 10 h and then heated to 80 °C for curing for 3 h to obtain the carbon fiber-reinforced modified resin material of this example.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that step 1) is omitted, and the carbon fiber is not acidified. Specifically:

[0048] 50 parts of carbon fiber, 10 parts of graphene oxide modified by silane coupling agent, 15 parts of polyethylene glycol, and 5 parts of alkylphenol polyoxyethylene ether were ultrasonically mixed evenly with acetone as the solvent to obtain Mixture I;

[0049] 100 parts of epoxy resin and 40 parts of triethylenetetramine were mixed and heated and stirred at 60 °C for 10 min to obtain Mixture II;

[0050] Mixture I and Mixture II were placed in a vacuum oven at 55 °C and mixed and stirred for 3 h. The obtained product was left at room temperature for 10 h and then heated to 80 °C for curing for 3 h;

[0051] The processes of the remaining steps were all referred to Example 1 to obtain the carbon fiber-reinforced modified resin material of this comparative example.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 1 is that step 2) is omitted, and the graphene oxide is not modified by silane coupling agent. Specifically:

[0054] 50 parts of acidified carbon fiber, 10 parts of graphene oxide, 15 parts of polyethylene glycol, and 5 parts of alkylphenol polyoxyethylene ether were ultrasonically mixed evenly with acetone as the solvent to obtain Mixture I;

[0055] 100 parts of epoxy resin and 40 parts of triethylenetetramine were mixed and heated and stirred at 60 °C for 10 min to obtain Mixture II;

[0056] Mixture I and Mixture II were placed in a vacuum oven at 55 °C and mixed and stirred for 3 h. The obtained product was left at room temperature for 10 h and then heated to 80 °C for curing for 3 h;

[0057] The processes of the remaining steps were all referred to Example 1 to obtain the carbon fiber-reinforced modified resin material of this comparative example.

[0058] Comparative Example 3

[0059] The difference between this comparative example and Example 1 is that polyethylene glycol in step 3) is omitted, and the processes of the remaining steps are all referred to Example 1 to obtain the carbon fiber-reinforced modified resin material of this comparative example.

[0060] Comparative Example 4

[0061] The difference between this comparative example and Example 1 is that alkylphenol polyoxyethylene ether in step 3) is omitted, and the processes of the remaining steps are all referred to Example 1 to obtain the carbon fiber-reinforced modified resin material of this comparative example.

[0062] The properties of the carbon fiber-reinforced modified resin materials prepared in Comparative Example 1 and Comparative Examples 1-4 are shown in Table 1 as follows.

[0063] Table 1

[0064] Tensile strength (MPa) <![CDATA[Impact toughness (KJ / m 2 )]]> Interlaminar shear strength (MPa) Example 1 1816 218 129 Comparative Example 1 1399 122 62 Comparative Example 2 1022 117 57 Comparative Example 3 985 94 48 Comparative Example 4 1577 161 77

[0065] As can be seen from Table 1, steps such as acid treatment of carbon fiber, modification of graphene oxide with silane coupling agent, addition of polyethylene glycol and alkylphenol polyoxyethylene ether play important roles in improving the mechanical properties of the carbon fiber-reinforced modified resin materials. The absence or omission of these steps will lead to a significant decrease in the tensile strength, impact toughness and interlaminar shear strength of the composite material.

[0066] This is because the acid treatment can improve the surface properties of the carbon fiber and increase the number of surface functional groups, thereby enhancing the interfacial bonding force between the carbon fiber and the resin matrix. The carbon fiber without acid treatment has fewer surface functional groups and weaker bonding force with the resin matrix, resulting in a decrease in the tensile strength, impact toughness and interlaminar shear strength of the composite material.

[0067] The silane coupling agent can improve the compatibility between graphene oxide and the resin matrix and enhance the interfacial bonding force. The graphene oxide without modification with silane coupling agent has poor dispersibility in the resin matrix and is prone to form aggregates, leading to a decrease in the mechanical properties of the composite material. At the same time, the interfacial bonding force between the unmodified graphene oxide and the resin matrix is weak, further reducing the tensile strength, impact toughness and interlaminar shear strength of the composite material.

[0068] In the present invention, polyethylene glycol, as a kind of polymer, has both a dispersing effect and a certain adhesive property. After omitting polyethylene glycol, both the dispersibility and adhesive property of the composite material will be affected. The uneven dispersion of graphene oxide in the resin matrix and the weakening of the interfacial bonding force between the carbon fiber and the resin matrix jointly lead to a decrease in the tensile strength, impact toughness and interlaminar shear strength of the composite material.

[0069] Alkylphenol polyoxyethylene ether is a non-ionic surfactant with good dispersing performance and a certain adhesive property. After omitting alkylphenol polyoxyethylene ether, the dispersibility of the composite material decreases, the graphene oxide is unevenly dispersed in the resin matrix and is prone to form aggregates. At the same time, the adhesive property of alkylphenol polyoxyethylene ether is also affected, resulting in a weakening of the interfacial bonding force between the carbon fiber and the resin matrix. These factors will also lead to a decrease in the tensile strength, impact toughness and interlaminar shear strength of the composite material.

[0070] Example 2

[0071] This example is used to explore the influence of different treatment methods of carbon fibers on the properties of the prepared carbon fiber-reinforced modified resin materials. Specifically, the acidification treatment of the carbon fibers in step 1) of Example 1 is adjusted as follows:

[0072] A. Dopamine treatment;

[0073] Prepare a 2 mg / mL dopamine solution using a 10 mmol / L Tris buffer solution;

[0074] The carbon fibers are refluxed with acetone at 100 °C for 24 h. The obtained product is immersed in the dopamine solution at room temperature for 24 h and then taken out, washed with deionized water multiple times until the filtrate is colorless and transparent. Finally, the fibers are placed in a vacuum oven at 60 °C and dried overnight to obtain dopamine-treated carbon fibers.

[0075] B. Silanization;

[0076] Under the condition of 60 °C, the carbon fibers are added to an ethanol solution with a KH570 concentration of 3 wt%, and magnetically stirred for 8 h to obtain silanized carbon fibers.

[0077] C. Air oxidation;

[0078] The carbon fibers are subjected to air oxidation treatment at 500 °C for 1.5 h to obtain air-oxidized carbon fibers.

[0079] The remaining preparation methods are all referred to Example 1. Replace the acidified carbon fibers with other functionalized carbon fibers to obtain the carbon fiber-reinforced modified resin materials prepared from different functionalized carbon fibers in this example. Measure their relevant properties and compare them with Example 1. The results are shown in Table 2.

[0080] Table 2

[0081]

[0082]

[0083] As can be seen from Table 2, in the solution of the present invention, different functionalized carbon fiber treatment methods have a significant impact on the properties of the prepared carbon fiber-reinforced modified resin materials. For example, dopamine treatment may form a relatively thick coating on the surface of the carbon fibers. Although this coating may improve the wettability and adhesion between the carbon fibers and the resin matrix, it may also introduce additional stress concentration points, resulting in a decrease in the mechanical properties of the composite material. In addition, if the dopamine coating fails to uniformly cover the surface of the carbon fibers, local defects may be formed, further weakening the mechanical properties of the composite material.

[0084] The mechanical properties of the composite material prepared from the carbon fiber after silanization treatment have decreased to a certain extent. This is because the silane coupling agent fails to effectively penetrate into the pores of the carbon fiber or fails to form good chemical bonds with the resin matrix, resulting in a weakened interfacial bonding force and thus reducing the mechanical properties of the composite material.

[0085] Air oxidation treatment is a relatively mild method for surface modification of carbon fibers. It cannot effectively remove impurities on the surface of carbon fibers and increase the number of functional groups like acid treatment. In addition, air oxidation treatment may also introduce some oxidation products or defects that are not conducive to mechanical properties.

[0086] Example 3

[0087] The difference between this example and Example 1 is that the amounts of acid-treated carbon fibers in step 3) are adjusted to 30 parts, 40 parts, 50 parts, 60 parts, and 70 parts respectively, and the other steps of the process are all referred to Example 1 to explore the influence of the amount of acid-treated carbon fibers on the properties of the prepared modified resin material. The relevant properties of the modified resin materials prepared with different contents of acid-treated carbon fibers are tested, and the results are shown in Table 3.

[0088] Table 3

[0089] Carbon fiber content Tensile strength (MPa) <![CDATA[Impact toughness (KJ / m 2 )]]> Interlaminar shear strength (MPa) 30 parts 982 98 45 40 parts 1578 163 86 50 parts 1816 218 129 60 parts 1762 154 98 70 parts 1421 112 74

[0090] It can be seen from Table 3 that the content of acid-treated carbon fibers has a significant impact on the properties of the prepared modified resin material. Too high or too low content of acid-treated carbon fibers may both lead to an increase in the non-uniformity of the interfacial bonding force. And in the composite material, the resin matrix plays a role in supporting and transmitting loads. When the content of acid-treated carbon fibers changes, the relative proportion between the resin matrix and it will also change. If the content of acid-treated carbon fibers is too high, the proportion of the resin matrix will be relatively reduced, which leads to a decrease in the toughness of the composite material; on the contrary, if the content is too low, it may cause the proportion of the resin matrix to be too high, affecting the rigidity and strength of the composite material.

[0091] Example 4

[0092] The difference between this example and Example 1 is that the amounts of graphene oxide modified by silane coupling agent in step 3) are adjusted to 6 parts, 8 parts, 10 parts, 12 parts, and 14 parts respectively, and the other steps of the process are all referred to Example 1 to explore the influence of the amount of graphene oxide modified by silane coupling agent on the properties of the prepared modified resin material. The relevant properties of the modified resin materials prepared with different amounts of graphene oxide modified by silane coupling agent are tested, and the results are shown in Table 4.

[0093] Table 4

[0094] Graphene oxide content Tensile strength (MPa) <![CDATA[Impact toughness (KJ / m 2 )]]> Interlaminar shear strength (MPa) 6 parts 1033 112 59 8 parts 1482 151 93 10 parts 1816 218 129 12 parts 1573 149 108 14 parts 1268 125 87

[0095] As can be seen from Table 4, the amount of graphene oxide modified by silane coupling agent has a significant impact on the properties of the prepared modified resin material. The modification with silane coupling agent can enhance the interfacial interaction between GO and the resin matrix. However, when the content of modified GO is too high or too low, the uniformity of the interfacial interaction may be affected. When the content of modified GO is too high, it may cause the resin matrix to be unable to fully infiltrate the GO sheets, forming interfacial defects; while when the content is too low, the interfacial bonding force between GO and the resin matrix may be insufficient.

[0096] Example 5

[0097] The difference between this example and Example 1 is that the amount of polyethylene glycol in step 3) is adjusted to be 5 parts, 10 parts, 15 parts, 20 parts, and 25 parts respectively. The processes of the remaining steps are all referred to Example 1 to explore the influence of the amount of polyethylene glycol on the properties of the prepared modified resin material. The relevant properties of the modified resin materials prepared with different amounts of polyethylene glycol are tested, and the results are shown in Table 5.

[0098] Table 5

[0099]

[0100]

[0101] In the solution of the present invention, the addition of polyethylene glycol can optimize the internal structure of the composite material, enabling a closer combination among epoxy resin, carbon fiber, and modified GO. This close combination helps to improve the overall mechanical properties of the composite material. Specifically, as a high molecular polymer, polyethylene glycol has strong hydrophilicity and can form hydrogen bonds with resin groups, thus playing a plasticizing role. Its addition may also change the structure of the resin matrix, including its crosslinking density, molecular chain length, etc. When the content of PEG is too high, it may interfere with the normal crosslinking process of the resin matrix, resulting in a decrease in crosslinking density and thus affecting the mechanical properties of the composite material.

[0102] The surface of acidified carbon fiber contains acidic functional groups such as carboxyl groups, and these functional groups can form hydrogen bonds with the hydroxyl groups in PEG. The formation of hydrogen bonds enhances the interaction between PEG and carbon fiber, helps to improve the dispersion and interfacial bonding force of carbon fiber in the epoxy resin matrix. At the same time, the good hydrophilicity of PEG can wet the surface of carbon fiber, reduce the interfacial tension between carbon fiber and the epoxy resin matrix, and promote the infiltration and coating of the resin matrix on carbon fiber, thereby improving their bonding effect.

[0103] In summary, as a bridging molecule, PEG can connect the modified GO and the epoxy resin matrix. The hydroxyl groups of PEG form chemical bonding or hydrogen bonding interactions with the silyl functional groups on the surface of the modified GO and the epoxy functional groups in the epoxy resin, thereby enhancing the interfacial bonding force between GO and the resin matrix.

[0104] However, when the content of polyethylene glycol is too high, its plasticizing effect may lead to a weakening of the intermolecular forces between the molecular chains of the resin matrix, thereby affecting the mechanical properties of the composite material. An appropriate amount of PEG can form a good interaction with the resin matrix, improving the interfacial bonding force and dispersibility of the composite material. However, when the PEG content is too high or too low, this interaction may become uneven, resulting in defects or stress concentration points inside the composite material.

[0105] Example 6

[0106] The difference between this example and Example 1 is that the dosages of alkylphenol polyoxyethylene ether in step 3) are adjusted to 1 part, 3 parts, 5 parts, 8 parts, and 10 parts respectively, and the processes of the remaining steps are all referred to Example 1 to explore the influence of the dosage of alkylphenol polyoxyethylene ether on the properties of the prepared modified resin material. The relevant properties of the modified resin materials prepared with different dosages of alkylphenol polyoxyethylene ether are tested, and the results are shown in Table 6.

[0107] Table 6

[0108]

[0109]

[0110] Since the molecular structure of alkylphenol polyoxyethylene ether contains a benzene ring and a polyoxyethylene ether group, these functional groups can interact with the functional groups in the resin matrix. An appropriate amount of alkylphenol polyoxyethylene ether can form a good interaction with the resin matrix, improving the interfacial bonding force and dispersibility of the composite material. However, when the content of alkylphenol polyoxyethylene ether is too high, it may interfere with the normal cross-linking process of the resin matrix, resulting in a decrease in cross-linking density, thereby affecting the mechanical properties of the composite material.

[0111] In addition, as a non-ionic surfactant, alkylphenol polyoxyethylene ether can act as a plasticizer in the resin, increasing the fluidity of the resin and also helping to improve the dispersibility of other fillers (such as carbon fiber, graphene oxide, etc.) in the resin. However, when the content of alkylphenol polyoxyethylene ether is too high or too low, its plasticizing effect and dispersibility may become uneven, resulting in defects or stress concentration points inside the resin.

[0112] In summary, based on the defects existing in the carbon fiber-reinforced modified resin composite material in the prior art, such as the large brittleness and poor compatibility of the matrix resin, the vulnerability of the interface layer, and the poor bonding between the resin and the carbon fiber, the present invention uses epoxy resin as the matrix, acidifies the carbon fiber, and combines graphene oxide modified by a silane coupling agent, polyethylene glycol, and alkylphenol polyoxyethylene ether. By deeply analyzing the interaction mechanism between each component and reasonably designing the formula, the interfacial bonding force of the carbon fiber-reinforced modified resin composite material is significantly improved, thereby improving the overall mechanical properties of the composite material. It has a wide application prospect in the fields of high-performance composite materials such as aerospace, automobile manufacturing, and electronic appliances.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A method for preparing a carbon fiber reinforced modified resin material, characterized in that: include, 40 to 60 parts of acidified carbon fiber, 8 to 12 parts of graphene oxide modified by a silane coupling agent, 10 to 20 parts of polyethylene glycol, and 3 to 8 parts of alkylphenol polyoxyethylene ether are uniformly mixed by ultrasonication with acetone as solvent to obtain a mixture I; 100 parts of epoxy resin and 30-50 parts of curing agent are mixed, heated and stirred until melted to obtain mixture II; The mixture I and the mixture II are placed in a vacuum oven for mixing and stirring, and the obtained product is placed at room temperature and then heated for curing to obtain a carbon fiber reinforced modified resin material.

2. The method for preparing a carbon fiber reinforced modified resin material according to claim 1, characterized in that: The preparation method of the acidified carbon fiber is: The carbon fiber and acetone were ultrasonically mixed in a mass volume ratio of 1 g: 10-15 ml, and then placed in a three-necked flask, refluxed at 60-70° C. for 24-48 hours, and after the reflux was completed, the supernatant was removed by centrifugation, and then vacuum dried; The obtained product is reacted with a mixed strong acid at a mass volume ratio of 1g:10-15ml at 70-80°C for 2-3h. After the reaction, the supernatant is removed by centrifugation, deionized water and anhydrous ethanol are added for shaking, and washing is repeated until the pH of the solution is alkaline, and then vacuum drying is performed to obtain acidified carbon fiber.

3. The method for preparing a carbon fiber reinforced modified resin material according to claim 2, characterized in that: The mixed strong acid is obtained by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1-3:1-3.

4. The method for preparing a carbon fiber reinforced modified resin material according to claim 1, characterized in that: The preparation method of the silane coupling agent-modified graphene oxide is: γ-aminopropyltriethoxysilane and water are mixed in a volume ratio of 1 to 3:9, and ultrasonicated for 30 to 60 minutes to obtain a silane coupling agent hydrolyzate; Graphene oxide powder and dispersant were added thereto, and ultrasonic treatment was continued for 30 minutes. After uniform dispersion, the temperature was raised to 80-90° C. and the reaction was carried out for 6-8 hours. The product was filtered and dried to obtain graphene oxide modified by a silane coupling agent.

5. The method for preparing a carbon fiber reinforced modified resin material according to claim 4, characterized in that: The mass fraction of the graphene oxide in the silane coupling agent hydrolyzate is 15-25%, and the mass ratio of the graphene oxide to the dispersant is 1:0.1-0.

3.

6. The method for preparing a carbon fiber reinforced modified resin material according to claim 1, characterized in that: The heating and stirring are performed until the mixture melts to obtain a mixture II, wherein the heating and stirring temperature is 55 to 75° C. and the heating and stirring time is 10 to 20 minutes.

7. The method for preparing a carbon fiber reinforced modified resin material according to claim 1, characterized in that: The mixture I and the mixture II are placed in a vacuum oven for mixing and stirring, wherein the mixing and stirring temperature is 55-60° C. and the time is 2-4 hours.

8. The method for preparing a carbon fiber reinforced modified resin material according to claim 1, characterized in that: The obtained product is placed at room temperature and then subjected to temperature-raising curing treatment, wherein the time of placing at room temperature is 10 to 14 hours.

9. The method for preparing a carbon fiber reinforced modified resin material according to claim 8, characterized in that: The curing treatment is performed at a temperature of 70 to 90° C. and for a time of 2 to 4 hours.

10. The carbon fiber reinforced modified resin material prepared by the preparation method according to any one of claims 1 to 9.

Images