Aramid fiber and two-dimensional-three-dimensional particle synergistic surface modification method
By employing a synergistic surface modification method involving high-energy ray treatment, graft polymerization, and graphene oxide nanoparticle sizing agents, the problem of poor interfacial shear strength in aramid fiber-reinforced resin matrix composites was solved, achieving efficient bonding between the fiber and the resin matrix.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AEROSPACE RES INST OF MATERIAL & PROCESSING TECH
- Filing Date
- 2023-11-20
- Publication Date
- 2026-05-22
AI Technical Summary
In existing aramid fiber reinforced resin matrix composites, the fiber-resin interfacial shear strength is poor and difficult to improve further.
A surface modification method using aramid fibers and two-dimensional-three-dimensional particles was employed. Through the synergistic effect of high-energy ray treatment, graft polymerization, and graphene oxide nanoparticle sizing agent, the surface roughness and active sites of the fibers were improved, enhancing the physical interlocking and chemical bonding between the fibers and the resin matrix.
It significantly improves the interfacial bonding performance between aramid fibers and the resin matrix, enhances the physical interlocking and chemical bonding between the fiber surface and the resin molecular chains, and improves the interfacial shear strength.
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Abstract
Description
Technical Field
[0001] This application relates to a surface modification method for aramid fibers and two-dimensional-three-dimensional particles, belonging to the field of aramid fiber modification technology. Background Technology
[0002] Aramid fiber reinforced resin matrix composites, with their unique rigid linear structure, possess advantages such as high strength, high modulus, and good insulation, and are widely used in high-end manufacturing fields such as military, transportation, and aerospace. However, high-performance resins such as epoxy, bismaleimide, and polyimide have strong chemical structural stability after curing, making it difficult to form chemical bonds with other structures. At the same time, the molecular conjugation effect and rigid benzene rings inside aramid fibers endow them with low activity and a halo surface, lacking grooves to form physical interlocking with other structures. Therefore, the poor bonding performance at the fiber-resin micro-interface has become a bottleneck problem restricting the further improvement of the performance of aramid fiber reinforced resin matrix composites.
[0003] Methods used domestically and internationally to enhance the micro-interface bonding properties of aramid fibers and resins can be broadly categorized into two types: molecular rearrangement and surface modification. One method involves using high-energy radiation to induce molecular rearrangement in aramid fibers, significantly increasing surface roughness by reducing molecular orientation along the fiber axis, while simultaneously increasing surface polarity to enhance wettability with the resin matrix. Another method involves introducing cross-linked networks or functionalized active sites onto the aramid fiber surface through graft polymerization, promoting chemical bonding and physical interlocking with the resin matrix. However, while molecular rearrangement and surface modification alone can improve micro-interface bonding properties to some extent, they often fail to achieve the desired results. Summary of the Invention
[0004] The technical problem solved by this application is to address the issue of poor interfacial shear strength between aramid fiber and resin matrix composites, and to provide a method for synergistic surface modification of aramid fiber and two-dimensional-three-dimensional particles, which can effectively enhance the interfacial shear strength between aramid fiber and resin matrix.
[0005] Combining two reinforcement methods (molecular rearrangement and surface modification) effectively can further improve the micro-interface bonding performance of aramid fiber-reinforced resin matrix composites. Furthermore, graphene oxide (GO), a nanomaterial with a unique two-dimensional layered structure, high specific strength, and high specific modulus, can effectively improve the surface roughness of aramid fibers. This method innovatively prepares a novel sizing agent, which introduces GO nanoparticles into the surface of aramid fibers through sizing treatment, enabling effective bonding. Simultaneously, through its entanglement with resin molecular chains, it effectively hinders the generation and propagation of microcracks at the fiber-resin micro-interface, improving the damage evolution mode of the fiber-resin micro-interface and effectively enhancing the bonding performance of the fiber-resin micro-interface.
[0006] The technical solution provided in this application is as follows:
[0007] The present invention discloses a two-dimensional-three-dimensional particle synergistic surface modification method for aramid fibers, which includes fiber surface activation, graft polymerization, and sizing with a novel sizing agent.
[0008] The method for surface modification of aramid fibers according to the present invention includes the following steps:
[0009] (1) Activate the surface of aramid fibers;
[0010] (2) Graft polymerization is performed on the surface of aramid fibers;
[0011] (3) A sizing agent is used to sizing the surface of aramid fibers.
[0012] In step (1) above, the method for surface activation of aramid fibers can be as follows: wash the aramid fibers with acetone or ethanol 10 to 20 times, dry them in an oven at 100°C for 1 to 3 hours, place them in a closed glass reactor, introduce a nitrogen atmosphere, and irradiate them under a 60Co irradiation source. The irradiation dose rate of the γ-ray irradiation treatment is 3 to 10 kGy / h, and the irradiation dose of the γ-ray irradiation treatment is 20 to 100 kGy. Rinse them with acetone or ethanol reagent 10 to 20 times, and then dry them in an oven at 80°C for 1 to 3 hours.
[0013] In step (2) above, the method for surface grafting polymerization of aramid fibers can be as follows: after ultrasonically vibrating the aramid fibers in ethanol or acetone solvent for 30 seconds, rinse them with deionized water 10 to 20 times, dry them in a vacuum oven at 60°C for 1 to 2 hours, and then cool them to room temperature. Slowly add Tris buffer to a 0.005 to 0.01 mol / L dopamine hydrochloride solution, adjust the pH value to 8 to 9, and immerse the dried aramid fibers in the above solution for 24 hours to obtain aramid fibers that have completed surface grafting polymerization.
[0014] In step (3) above, the preparation method of the sizing agent can be as follows: add graphene oxide (GO) nanoparticles and KH550 surfactant to water, and then sonicate for 1 hour to obtain GO suspension, thus obtaining the sizing agent.
[0015] In the sizing agent, the mass ratio of KH550 surfactant to GO nanoparticles should be 1:3 to 1:5.
[0016] The total mass content of graphene oxide (GO) nanoparticles and KH550 surfactant in the sizing agent is 0.1wt% to 0.5wt%.
[0017] In step (3) above, the method of sizing the surface of aramid fibers can be as follows: immerse the aramid fibers that have completed surface grafting polymerization in a sizing agent and react at room temperature for 0.5 to 2 hours to obtain aramid fibers that have completed surface sizing.
[0018] Invention principle: This invention utilizes high-energy ray treatment, graft polymerization, and sizing modification of aramid fibers with graphene oxide (GO) nanoparticles.
[0019] First, strong-penetrating gamma rays are used to promote molecular rearrangement in the aramid fiber core layer, improving its orientation and crystallinity, and enhancing the core-sheath structure. Simultaneously, potential active sites on the fiber surface are activated, conveniently, efficiently, and controllably reducing the energy barrier for grafting reactions on the aramid fiber surface, thus achieving surface activation and facilitating subsequent graft polymerization. Then, three-dimensional dopamine groups are introduced into the fiber surface via graft polymerization, significantly improving surface roughness, mitigating interfacial damage accumulation, and enhancing the physical interlocking between the fiber surface and resin molecular chains and nanoparticles. Furthermore, a novel aramid fiber sizing agent formulation is designed, utilizing KH550 to enhance the sizing effect of graphene oxide (GO). Surface activity is enhanced, improving the compatibility between inorganic nanoparticles and water molecules. After ultrasonic dispersion, a stable GO nanoparticle suspension without significant sedimentation can be formed during the sizing process, providing technical assurance for batch stability in subsequent sizing steps on aramid fibers. Furthermore, the sizing process allows GO nanoparticles to be deposited on the surface of aramid fibers. This two-dimensional reinforcement with high strength, high stiffness, and other excellent properties further improves the surface roughness of aramid fibers, enhances the physical interlocking between the aramid fiber surface and the resin matrix molecular chains, and improves the interfacial bonding performance between aramid fibers and the resin matrix through a two-dimensional-three-dimensional particle synergistic surface modification method.
[0020] Furthermore, this collaborative surface method adopts a modular design, allowing for the selection of processing modules as needed based on various factors such as the state of different types of aramid fibers, performance requirements, and cost control. This approach can improve the versatility of the modification method while effectively modifying the fibers.
[0021] In summary, this application includes at least the following beneficial technical effects:
[0022] Compared with the prior art, the advantages of the present invention are:
[0023] (1) This invention enhances the interfacial bonding performance of aramid fibers through the synergistic effects of physical interlocking and chemical bonding. High-energy particle treatment can significantly increase the number of grooves on the fiber surface by promoting molecular rearrangement. The introduction of two-dimensional GO nanoparticles also effectively improves the surface roughness of the fiber and enhances its physical interlocking with the resin matrix. The introduction of three-dimensional dopamine groups further increases the number of active sites on the surface of aramid fibers and enhances the chemical bonding between the fiber and the resin matrix. The synergistic effect of the two enhances the interfacial bonding performance of aramid fibers.
[0024] (2) The present invention uses surfactants to prepare a GO nanoparticle suspension that is stable and does not undergo significant sedimentation during the production cycle of the sizing process, thereby improving the stability of the novel sizing agent;
[0025] (3) The present invention adopts a modular design method, and selects two-dimensional or three-dimensional modified particles as needed based on factors such as fiber state, performance requirements and cost control, thereby improving the universality of the two-dimensional-three-dimensional particle synergistic surface modification method. Detailed Implementation
[0026] The technical solution of the present invention will be further described below with reference to the embodiments.
[0027] Example 1
[0028] The preparation process of the modified aramid fiber in this embodiment is as follows:
[0029] (1) Surface activation of aramid fibers
[0030] Take 0.5g of aramid fiber, rinse it 20 times with acetone, dry it in an oven at 100℃ for 3 hours, place it in a sealed glass reactor, and purge it with nitrogen atmosphere. 60 The treatment was carried out under a Co irradiation source with an irradiation dose rate of 10 kGy / h and a irradiation dose of 100 kGy. The treatment was rinsed 20 times with acetone and then dried in an oven at 80°C for 3 hours.
[0031] (2) Surface grafting polymerization of aramid fibers
[0032] After ultrasonically vibrating the aramid fiber in ethanol or acetone for 30 seconds, rinse it 20 times with deionized water, dry it in a vacuum oven at 60°C for 2 hours, and then cool it to room temperature. Tris buffer is slowly added to a 0.01 mol / L dopamine hydrochloride solution to adjust the pH to 8.5. The dried aramid fiber is then immersed in the above solution for 24 hours to obtain aramid fiber with completed surface grafting polymerization.
[0033] (3) A new type of sizing agent is used to sizing the surface of aramid fibers.
[0034] Step 31: Add 0.4 wt% graphene oxide (GO) nanoparticles and 0.08 wt% KH550 surfactant to water, and then sonicate for 1 hour to obtain a GO suspension, thus obtaining a novel sizing agent.
[0035] Step 32: Immerse the aramid fibers that have completed surface grafting polymerization in a novel sizing agent and react at room temperature for 2 hours to obtain aramid fibers with completed surface sizing.
[0036] Example 2
[0037] The preparation process of the modified aramid fiber in this embodiment is as follows:
[0038] (1) Surface activation of aramid fibers
[0039] Take 0.5g of aramid fiber, rinse it 10 times with acetone, dry it in an oven at 100℃ for 1 hour, place it in a sealed glass reactor, and purge it with nitrogen atmosphere. 60 The treatment was carried out under a Co irradiation source with an irradiation dose rate of 3 kGy / h and a irradiation dose of 30 kGy. The treatment was rinsed 10 times with acetone and then dried in an oven at 80°C for 1 h.
[0040] (2) Surface grafting polymerization of aramid fibers
[0041] After ultrasonically vibrating the aramid fiber in ethanol or acetone for 30 seconds, rinse it 10 times with deionized water, dry it in a vacuum at 60°C for 1 hour, and then cool it to room temperature. Add Tris buffer slowly to a 0.005 mol / L dopamine hydrochloride solution to adjust the pH to 8. Immerse the dried aramid fiber in the above solution for 24 hours to obtain aramid fiber with completed surface grafting polymerization.
[0042] (3) A new type of sizing agent is used to sizing the surface of aramid fibers.
[0043] Step 31: Add 0.1 wt% graphene oxide (GO) nanoparticles and 0.03 wt% KH550 surfactant to water, and then sonicate for 1 hour to obtain a GO suspension, thus obtaining a novel sizing agent.
[0044] Step 32: Immerse the aramid fibers that have completed surface grafting polymerization in a novel sizing agent and react at room temperature for 0.5 h to obtain aramid fibers with completed surface sizing.
[0045] The surface-modified aramid fiber monofilaments prepared in Examples 1 and 2 were taken out and used to prepare micro-debonding test specimens together with epoxy resin. The interfacial shear strength was tested using a micro-debonding test device. The test results are shown in Table 1 below.
[0046] Example 3
[0047] The only difference from Example 1 is that Tris buffer was slowly added to a 0.008 mol / L dopamine hydrochloride solution to adjust the pH to 8.5.
[0048] Example 4
[0049] The only difference from Example 1 is that Tris buffer was slowly added to a 0.005 mol / L dopamine hydrochloride solution to adjust the pH to 8.5.
[0050] Example 5
[0051] The only difference from Example 1 is that the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is 0.3 wt%; the mass ratio of graphene oxide nanoparticles to KH550 surfactant is the same as in Example 1.
[0052] Example 6
[0053] The only difference from Example 1 is that the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is 0.12 wt%; the mass ratio of graphene oxide nanoparticles to KH550 surfactant is the same as in Example 1.
[0054] Comparative Example 1
[0055] Using unactivated aramid fibers as samples, surface grafting polymerization of the aramid fibers and sizing with a novel sizing agent were performed according to the method in Example 1. Micro-debonding samples were prepared according to the method of the Example, and interfacial shear strength tests were conducted. The test results are shown in Table 1 below.
[0056] Comparative Example 2
[0057] The aramid fiber surface was activated according to the method in Example 2, without surface grafting polymerization. A novel sizing agent was used to sizing the aramid fiber surface, also according to Example 2. Micro-debonding samples were prepared according to the method of the examples, and interfacial shear strength tests were performed. The test results are shown in Table 1 below.
[0058] Comparative Example 3
[0059] The aramid fiber surface activation and surface grafting polymerization were performed according to the method in Example 2, without using a novel sizing agent to sizing the aramid fiber surface. Micro-debonding samples were prepared according to the method of the Example, and interfacial shear strength tests were conducted. The test results are shown in Table 1 below.
[0060] Comparative Example 4
[0061] No surface activation or graft polymerization was performed on the aramid fibers, and no novel sizing agent was used to sizing the aramid fiber surface. Micro-debonding samples were prepared according to the method described in the example, and interfacial shear strength tests were conducted. The test results are shown in Table 1 below.
[0062] Comparative Example 5
[0063] The only difference from Example 1 is that Tris buffer was slowly added to a 0.02 mol / L dopamine hydrochloride solution to adjust the pH to 8.5.
[0064] Comparative Example 6
[0065] The only difference from Example 1 is that Tris buffer was slowly added to a 0.002 mol / L dopamine hydrochloride solution to adjust the pH to 8.5.
[0066] Comparative Example 7
[0067] The only difference from Example 1 is that the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is 0.6 wt%; the mass ratio of graphene oxide nanoparticles to KH550 surfactant is the same as in Example 1.
[0068] Comparative Example 8
[0069] The only difference from Example 1 is that the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is 0.06 wt%; the mass ratio of graphene oxide nanoparticles to KH550 surfactant is the same as in Example 1.
[0070] Table 1. Test results of interfacial bonding performance of micro-debonded samples
[0071]
[0072]
[0073] As can be seen from the table, the only difference between Examples 1, 3, and 4 is the concentration of dopamine hydrochloride solution. When the dopamine solution concentration is 0.01 mol / L, 0.008 mol / L, and 0.005 mol / L, the interfacial bonding between the modified aramid fiber and the resin matrix is good, and the interfacial shear strength reaches above 50 MPa. However, in Comparative Examples 5 and 6, when the dopamine solution concentration is adjusted to 0.02 mol / L and 0.002 mol / L, respectively, the interfacial shear strength is poor. This is because a dopamine layer is formed on the surface of the aramid fiber after graft polymerization. This layer increases the surface roughness of the fiber and also serves as a carrier layer for the two-dimensional nanoparticles in the sizing agent. When the dopamine solution concentration is too high, the dopamine layer deposited on the fiber surface is too thick and easily falls off, becoming a weak area at the interface. When the dopamine solution concentration is too low, the dopamine layer deposited on the fiber surface is too thin, and there may be some surface areas that are not covered. At the same time, the number of two-dimensional nanoparticles that can be carried is limited, resulting in poor two-dimensional-three-dimensional synergistic reinforcement effect.
[0074] As can be seen from the table, in Examples 1, 5, and 6, the only difference lies in the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent. When the total content is 0.48 wt%, 0.3 wt%, and 0.12 wt%, the interfacial bonding between the modified aramid fiber and the resin matrix is good, and the interfacial shear strength reaches above 48 MPa. However, in Comparative Examples 7 and 8, when the total content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is adjusted to 0.6 wt% and 0.06 wt%, respectively, the interfacial shear strength is poor. This is because, under the action of surfactant, nanoparticles will deposit on the fiber surface. When the mass fraction is too high, graphene oxide will agglomerate on the fiber surface, affecting the quality of interfacial bonding. When the mass fraction is too low, graphene oxide is insufficient to be uniformly deposited on the entire fiber surface, and there may be some surface areas that are not covered, resulting in poor two-dimensional-three-dimensional synergistic reinforcement effect.
[0075] As can be seen from the table, Comparative Examples 1, 2, and 3 did not employ all three steps; they did not include the three stages of aramid fiber surface activation, aramid fiber surface grafting polymerization, and sizing with a novel sizing agent. Compared with Examples 1 and 2, the interfacial shear strength decreased to some extent in all three examples. However, compared with Comparative Example 4, the interfacial shear strength increased by 12.1%, 4.6%, and 8.3%, respectively. This indicates that the three stages of aramid fiber surface activation, aramid fiber surface grafting polymerization, and sizing with a novel sizing agent can all improve the interfacial bonding performance between aramid fibers and the resin matrix, and performing all or part of the modification steps improved the interfacial shear strength.
[0076] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.
[0077] The contents not described in detail in this application specification are common knowledge to those skilled in the art.
Claims
1. A method for two-dimensional-three-dimensional particle-synergistic surface modification of aramid fibers, characterized in that: include The surface of aramid fibers was activated by irradiation to obtain activated aramid fibers. The activated aramid fibers were grafted with dopamine solution to obtain aramid fibers that had completed surface grafting polymerization. Aramid fibers that have undergone surface grafting polymerization are sized using a sizing agent. The fiber surface activation includes placing the aramid fibers in a closed reactor, introducing nitrogen or an inert gas atmosphere, and subjecting them to irradiation treatment. The irradiation dose rate for gamma-ray irradiation treatment is 3-10 kGy / h, and the irradiation dose for gamma-ray irradiation treatment is 20-100 kGy. The preparation method of the sizing agent includes adding graphene oxide nanoparticles and KH550 surfactant to water, and ultrasonically preparing a graphene oxide suspension to obtain the sizing agent. The total mass content of graphene oxide nanoparticles and KH550 surfactant in the sizing agent is 0.1 wt% to 0.5 wt%. The mass ratio of KH550 surfactant to graphene oxide nanoparticles in the sizing agent is 1:3 to 1:
5. The grafting polymerization includes slowly adding Tris buffer to a 0.005~0.01mol / L dopamine hydrochloride solution, adjusting the pH value to 8~8.5 to obtain a grafting solution, and immersing aramid fibers in the grafting solution for 24h~48h to obtain aramid fibers that have completed surface grafting polymerization.
2. The method for two-dimensional-three-dimensional particle synergistic surface modification of aramid fibers according to claim 1, characterized in that: The aramid fibers were washed with acetone or ethanol and dried before and after irradiation treatment.
3. The method for two-dimensional-three-dimensional particle synergistic surface modification of aramid fibers according to claim 1, characterized in that: The irradiation source for the irradiation treatment is a 60Co irradiation source.
4. The method for two-dimensional-three-dimensional particle synergistic surface modification of aramid fibers according to claim 1, characterized in that: The sizing process involves immersing the aramid fibers that have undergone surface grafting polymerization in a sizing agent and reacting at room temperature for 0.5 to 2 hours.
5. An aramid fiber, characterized in that: The aramid fiber was prepared by a two-dimensional-three-dimensional particle synergistic surface modification method according to any one of claims 1-4.