A filler and a surface modification method thereof, a high-viscosity resin-based self-lubricating composite material and a preparation method thereof

Abstract

The application relates to the field of self-lubricating composite materials, and mainly relates to a filler and a surface modification method thereof, a high-viscosity resin-based self-lubricating composite material and a preparation method thereof.A filler comprises the following components: fibers, net framework nanosheets, two-dimensional lubricating nanomaterials and ionic liquids; the mass ratio of the fibers, the net framework nanosheets, the two-dimensional lubricating nanomaterials and the ionic liquids is 100:(1-10):(0.5-5):(0.1-2). A high-viscosity resin-based self-lubricating composite material comprises a filler and a resin matrix.The application can fundamentally solve the problems of difficult dispersion of the filler, poor infiltration, weak combination of the filler and the resin matrix and the like without reducing the viscosity of the resin, and significantly improves the self-lubricating performance of the composite material.

Description

Technical Field

[0001] This application relates to the field of self-lubricating composite materials, and mainly to a filler and its surface modification method, a high-viscosity resin-based self-lubricating composite material and its preparation method. Background Technology

[0002] Self-lubricating composite materials have important applications in high-end equipment such as aviation, aerospace, and heavy-duty bearings. They are typically composed of a high-viscosity resin matrix (such as bismaleimide, bisphenol A cyanate, or cyanate-bismaleimide copolymer) combined with fiber-reinforced fillers and lubricating fillers. Due to their high crosslinking density, excellent heat resistance (glass transition temperature is usually above 200℃), and high mechanical strength, these resins are irreplaceable matrix materials for meeting the demanding service requirements.

[0003] However, there are two common technical problems in the preparation of self-lubricating composite materials: First, the fiber fillers are prone to sticking together in bundles during production, cutting or storage, which affects resin wetting; second, the high viscosity resin has poor fluidity and is difficult to penetrate into the fiber bundle, resulting in uneven filler dispersion and poor interface wetting, which ultimately reduces the mechanical properties and tribological properties of the composite material.

[0004] To address the above problems, existing technologies mainly employ three types of improvement methods, but each has its own obvious limitations.

[0005] The first type involves conventional surface modification or the addition of coupling agents, but this only improves chemical compatibility and cannot solve the physical barriers caused by fiber adhesion. The second type involves reducing resin viscosity, but this directly sacrifices the resin's mechanical and heat resistance properties, making it counterproductive. The third type involves physically breaking down the fibers, but without subsequent interface design, the broken-down fibers are prone to re-aggregating during mixing, and the surface still lacks the driving force to guide resin wetting.

[0006] From the perspective of interface principles, the root cause of the difficulty in wetting high-viscosity resins lies in the mismatch between the interfacial energy of fibers and resins and the lack of capillary driving force. In existing solutions, material selection and process arrangement are disconnected, leading to a superposition of three problems: fiber adhesion, uneven dispersion, and poor wetting. Therefore, there is an urgent need for a modification process that deeply integrates interfacial gradient materials with synergistic processes without reducing resin viscosity, thereby fundamentally solving both wetting and lubrication problems simultaneously. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this application is to provide a filler and its surface modification method, a high viscosity resin-based self-lubricating composite material and its preparation method. The aim is to fundamentally solve the problems of difficult filler dispersion, poor wetting and weak bonding ability between filler and matrix without reducing the resin viscosity by constructing a functional gradient interface composite structure composed of network framework nanosheets, two-dimensional lubricating nanomaterials and ionic liquid on the fiber surface, combined with the synergistic process of dispersing-self-assembly construction-vacuum mixing.

[0008] The technical solution of this application is as follows: A filler comprising the following components: fibers, mesh framework nanosheets, two-dimensional lubricating nanomaterials, and ionic liquid; The mass ratio of the fiber, the mesh framework nanosheet, the two-dimensional lubricating nanomaterial, and the ionic liquid is 100:(1~10):(0.5~5):(0.1~2).

[0009] Furthermore, the fiber includes one or more of carbon fiber, aramid fiber, fluorinated fiber, and glass fiber; The network framework nanosheets include one or a mixture of two types of covalent organic framework nanosheets and two-dimensional conjugated metal-organic framework nanosheets. The two-dimensional lubricating nanomaterial includes one or more of graphyne, purple phosphorus, and black phosphorus. The ionic liquid includes one or more imidazole ionic liquids.

[0010] This application also provides a method for surface modification of fillers, including the following steps: The fibers are subjected to a pretreatment to regularize their structure. The processed fibers, the mesh framework nanosheets, the two-dimensional lubricating nanomaterials, and the ionic liquid are mechanically mixed to obtain a filler.

[0011] Furthermore, the mechanical mixing is carried out using a planetary ball milling method; The ball milling conditions are as follows: rotation speed: 100~300 rpm; time: 2~3 h; ball-to-material ratio: 10:1~30:1.

[0012] Furthermore, the pretreatment for structural regularization includes one or more of the following: mechanical dispersing, sieving, drying, and surface activation.

[0013] This application also provides a high-viscosity resin-based self-lubricating composite material with a self-assembly functional gradient interface structure, comprising a filler and a resin matrix; The filler content is 20~60 wt.%.

[0014] Furthermore, the resin matrix is ​​one or a mixture of two of bismaleimide and cyanate ester-bismaleimide copolymer.

[0015] This application also provides a method for preparing a high-viscosity resin-based self-lubricating composite material with a self-assembled functional gradient interface structure, comprising the following steps: The filler and the resin matrix are mixed in a vacuum environment to obtain a mixture; After the mixture is cured and molded, a high-viscosity resin-based self-lubricating composite material is obtained.

[0016] Furthermore, in the vacuum environment, the vacuum level is below 200 Pa; The filler and the resin matrix are mixed in a vacuum environment using a staged mixing method, starting with a low speed and then increasing to a high speed.

[0017] Furthermore, the curing conditions for the curing molding are as follows: heating to 160±10℃ at a rate of 3~6℃ / min, pressure: 3 MPa~6 MPa; heat and pressure holding time: 6 h~12 h.

[0018] Compared with the prior art, this application has the following beneficial effects: 1. This application deviates from the conventional approach to resin modification, instead focusing on filler surface design. Conventional resin modification often requires adjusting the resin formulation (e.g., introducing monomers with different functionalities), which is not only cumbersome and costly but can also adversely affect the resin's mechanical and heat resistance properties. This application constructs a gradient interface structure on the fiber surface through an entropy-driven self-assembly mechanism, enabling high-viscosity resin to spontaneously wet the fiber (filler) surface, rather than forcibly dispersing it by reducing resin viscosity or increasing shear strength. This method achieves a good interfacial bond between the filler and the resin matrix without sacrificing the original properties of the resin matrix.

[0019] 2. This application introduces network framework nanosheets and two-dimensional lubricating nanomaterials as interfacial layer building blocks. The regular nanopores of the network framework nanosheets can form a capillary network, significantly enhancing the interfacial bonding force between the resin matrix and fibers, and improving the mechanical strength of the composite material. The two-dimensional lubricating nanomaterials, with their interlayer slip characteristics and low shear resistance, can form a stable lubricating film during friction, endowing the interface with self-lubricating function. Together with ionic liquids, these two materials construct a functionally graded interfacial structure that combines high mechanical load-bearing capacity with excellent friction-reducing and wear-resistant properties. This material combination has unique performance advantages in the field of high-viscosity resin-based self-lubricating composite materials.

[0020] 3. The interface layer construction process in this application employs a mechanically assisted self-assembly method, which eliminates the need for complex chemical synthesis steps, making it simple to operate and easy to scale up. Simultaneously, the shearing action during ball milling promotes the dispersion and encapsulation of the two-dimensional lubricating nanomaterials without causing significant damage to the fibers, resulting in mild process conditions. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the molecular structure of the covalent organic framework nanosheet used in Example 1 of this application.

[0022] Figure 2 The images show the morphology of the composite materials obtained in Example 1 and Comparative Examples 1-3 as observed by a super depth-of-field microscope.

[0023] Figure 3 This is a graph showing the compressive strength of the composite materials obtained in Example 1 and Comparative Examples 1-3. (Material dimensions: width = height = 10 mm; thickness = 5 mm) Figure 4 The graphs show the friction coefficients of the composite materials obtained in Example 1 and Comparative Examples 1-3. (The curves have been smoothed – method: Savitzky-Golay, window size: 100, polynomial order: 2.) Detailed Implementation

[0024] This application provides a filler and its surface modification method, a high-viscosity resin-based self-lubricating composite material with a self-assembled interface gradient structure, and its preparation method. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following provides further detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0025] This application provides a filler comprising the following components: fibers, mesh framework nanosheets, two-dimensional lubricating nanomaterials, and ionic liquids.

[0026] The mass ratio of fiber, mesh framework nanosheet, two-dimensional lubricating nanomaterial, and ionic liquid is 100:(1~10):(0.5~5):(0.1~2).

[0027] More preferably, the mass ratio of the mesh framework nanosheets to the two-dimensional lubricating nanomaterials is 10:1 to 1:5, preferably 5:1 to 1:3, and more preferably 3:1 to 1:1.

[0028] Fibers include one or more of the following: carbon fiber, aramid fiber, fluorinated fiber, and glass fiber.

[0029] Network framework nanosheets include one or a combination of two types of covalent organic framework nanosheets (COFs) and two-dimensional conjugated metal-organic framework nanosheets (2D c-MOF Nanosheets).

[0030] Two-dimensional lubricating nanomaterials include one or more of graphyne, purple phosphorus, and black phosphorus.

[0031] The ionic liquid is selected from one or more imidazole ionic liquids. Imidazole ionic liquids include, but are not limited to, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

[0032] This application preferentially uses imine-based COF nanosheets as the interface layer. The imine bonds (–C=N–) of these nanosheets are highly compatible with the active groups in the matrix of imine-based high-temperature and high-strength resins such as bismaleimide resin. Through hydrogen bonding and chemical bonding, the bonding strength of the fiber / resin interface can be significantly enhanced, inhibiting fiber pull-out and interface debonding. Thus, under the synergistic effect of chemical anchoring and physical capillary network, the mechanical load-bearing capacity of the composite material is further improved.

[0033] This application also provides a method for surface modification of fillers, comprising the following steps: Step 1: Pretreatment for fiber structure regularization: The fibers are mechanically broken up to separate the bundled fibers into a loosely distributed state, so that the fibers can be fully impregnated in the next step.

[0034] The preferred method for dispersing is to use a pulverizing device for intermittent pulverization, combined with cooling measures to avoid temperature rise.

[0035] Preferably, the dispersed fibers are sieved to remove excessively long fibers and fine powder. A sieve of 50 to 200 mesh can be used for sieving.

[0036] Preferably, the sieved fibers are dried. The drying temperature is 80~150℃, and the time is 1~4 h.

[0037] More preferably, for surface-inert fibers, surface activation can be further performed by methods such as irradiation or plasma treatment in order to facilitate subsequent surface modification.

[0038] Preferably, the electron beam irradiation dose during irradiation treatment is 150~250 kGy.

[0039] Step 2: Construction of the fiber surface interface gradient structure: The fibers treated in step (1) are placed in a planetary ball mill along with the mesh framework nanosheets, two-dimensional lubricating nanomaterials, and ionic liquid for mixing. Under mechanical shearing, each component is adsorbed and encapsulated on the fiber surface, forming a composite interface layered structure with functional gradient distribution.

[0040] Regarding the layered structure of the composite interface with functional gradient distribution: Mesh framework nanosheets and ionic liquids are preferentially mixed to improve interfacial dispersion and wetting properties. Subsequently, two-dimensional lubricating nanomaterials are introduced to achieve synergistic construction and functional zoning of the interfacial structure. The resulting interfacial layer exhibits a gradient structure from the inside out: the inner layer is dominated by mesh framework nanosheets for interfacial support and resin penetration channels, while the outer layer is a low-shear-resistance interface formed by two-dimensional lubricating nanomaterials. Ionic liquids act as interfacial regulation mediators throughout, enhancing the compatibility and synergistic effect between components.

[0041] Preferably, the irradiated fibers, mesh framework nanosheets, and ionic liquid are premixed before being further mixed with the two-dimensional lubricating nanomaterials.

[0042] The ball milling conditions are as follows: rotation speed: 100~300 rpm; premixing time: 10~30 min; total mixing time: 2~3 h; ball-to-material ratio: 10:1~30:1.

[0043] After ball milling, the packing material is obtained.

[0044] This application also provides a high-viscosity resin-based self-lubricating composite material with a self-assembly functional gradient interface structure, comprising a resin matrix and fillers.

[0045] The filler content is 20~60 wt.%.

[0046] The resin matrix is ​​one or a mixture of two of the following: bismaleimide and cyanate ester-bismaleimide copolymer.

[0047] This application also provides a method for preparing a high-viscosity resin-based self-lubricating composite material with a self-assembled functional gradient interface structure, comprising the following steps: Step A: Vacuum impregnation and mixing treatment: The filler and resin matrix are placed together in a planetary vacuum mixer and mixed under vacuum, allowing the resin matrix to impregnate the fiber surface. After mixing, a mixture is obtained.

[0048] The vacuum level of vacuum mixing is below 200 Pa.

[0049] Vacuum mixing employs a phased approach of increasing the rotation speed: first, premixing at 200-400 rpm for 1-10 minutes, then increasing to 600-1000 rpm for vacuum impregnation and treatment for 5-30 minutes.

[0050] The vacuum mixing process involves alternating forward and reverse rotation.

[0051] In a vacuum environment, the gas inside the system is removed, increasing the free energy at the fiber interface between the resin matrix and the filler. According to thermodynamic principles, the system tends to reduce the interfacial energy, so the resin matrix spontaneously spreads on the fiber surface of the filler. At this point, the interfacial gradient structure constructed in step 2 plays a crucial guiding role—the resin matrix gradually penetrates from the outer layer to the inner layer along the gradient direction of the interfacial energy, eventually entering the nanopores on the fiber surface and achieving full wetting.

[0052] Step B: Curing and shaping: The mixture is poured into a square mold and heated and pressurized to cure, resulting in a high-viscosity resin-based self-lubricating composite material.

[0053] Preferably, the curing conditions are as follows: heating to 160±10℃ at a rate of 3~6℃ / min, pressure: 3 MPa~6 MPa; holding time: 6 h~12 h, and then cooling to room temperature with the furnace.

[0054] There is a clear logical relationship between the steps in this application—first, the fibers are dispersed to expose the surface (step 1), then an interface layer is constructed to guide wetting (step 2), and finally, mixing is completed in a vacuum (step A)—rather than a simple superposition of single steps. This chain-like synergistic mechanism allows for precise control of the fiber state at different stages, effectively improving the stability and repeatability of the process.

[0055] The core idea of ​​this process is to replace resin bulk modification with interface engineering, achieving performance breakthroughs through synergistic innovation in process and materials. This method constructs a functionally graded interface composite layer on the fiber surface, consisting of a network framework nanosheet, two-dimensional lubricating nanomaterials, and an ionic liquid. The network framework nanosheets, such as the nanopores of a covalent organic framework, provide resin wetting channels; the two-dimensional nano-lubricating materials, such as graphdiene, impart self-lubricating properties to the interface; and the ionic liquid regulates the interface polarity and distribution, and promotes the synergistic stability of the aforementioned two types of functional components. These three components are not simply superimposed, but rather form a mutually coupled functional system in the interface region: the framework structure promotes resin wetting, enhanced wetting facilitates the function of the lubricating components, and the ionic liquid further stabilizes the interface structure and improves the compatibility between the functional layer and the resin matrix. Through these synergistic effects, the unification of enhanced wetting, interface enhancement, and lubrication enhancement in high-viscosity resin systems is achieved. This not only overcomes the limitations of the traditional "viscosity reduction and penetration promotion" approach, improving the bonding ability between fillers and the resin matrix, but also overcomes the technical limitation that single-function modification cannot simultaneously achieve both wetting and lubrication.

[0056] The present application will be further described below through specific embodiments.

[0057] Example 1 A method for preparing a high-viscosity resin-based self-lubricating composite material with a self-assembled functional gradient interface structure includes the following steps: Step (1) Pretreatment for structural regularization of fiber fillers: First, use a pulverizer to physically break up the PTFE fiber bundles. Use an intermittent pulverization program and combine it with external cooling with cold water to avoid excessive temperature from causing changes in fiber properties.

[0058] The powdered fibers were removed, passed through a 50-mesh sieve to remove excessively long fibers, and then through a 200-mesh sieve to remove most of the unwanted fine powder. The collected fibers were then vacuum-dried at 120°C for 2 hours to remove moisture. Due to the inertness of the PTFE fiber surface, further pre-irradiation treatment (electron beam irradiation dose of 200 kGy) is required to activate its surface for further modification.

[0059] Step (2) Construction of the fiber surface interface gradient structure: Irradiated fibers and covalent organic framework nanosheets (TpPa-1 type, molecular structure formula referenced) Figure 1 The mass ratio of graphdiyne nanosheets and ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) is 100:5:2:1.

[0060] First, the irradiated fibers, TpPa-1, and ionic liquid were premixed, and then zirconia balls were added at a ball-to-material ratio of 20:1. The resulting mixture was placed in a Teflon container and ball-milled at 250 rpm for 30 minutes using a planetary vacuum degassing machine. Then, graphyne nanosheets were added and ball-milled for 2 hours to complete the self-assembly and encapsulation of the nanomaterials under mechanical shearing.

[0061] The ball-milled material was then passed through a 200-mesh sieve to obtain a surface-modified filler.

[0062] Step (3) Vacuum wetting and low-disturbance mixing: The surface-modified filler and bismaleimide matrix were mixed at a mass ratio of 4:6 and placed in a planetary vacuum degassing machine. During the mixing process, the mixture was first premixed at 200 rpm for 5 minutes to initially disperse the filler in the resin. Then, the rotation speed was increased to 800 rpm, and the vacuum mode was activated to reduce the system vacuum to below 100 Pa, and mixing continued for 10 minutes. During the mixing process, the rotation direction was switched every 2 minutes to redistribute the filler under different flow field conditions.

[0063] After mixing, a mixture is obtained.

[0064] Step (4) Curing and shaping: The mixture is injected into a mold, heated and pressurized to cure, resulting in a high-viscosity resin-based self-lubricating composite material.

[0065] The curing conditions were as follows: heating to 160°C at a rate of 5°C / min, pressure: 4.5 MPa; holding time: 8 h, and then cooling to room temperature with the furnace.

[0066] Comparative Example 1 The difference from Example 1 is as follows: The fiber is subjected to only the structural regularization pretreatment of the fiber filler in step (1), and the construction of the fiber surface interface gradient structure in step (2) is not performed. The remaining steps are the same as in Example 1.

[0067] That is, the composite material includes the following preparation methods: Step A: Vacuum impregnation and low-disturbance mixing: The irradiated fibers were used as fillers and directly mixed with the bismaleimide matrix at a mass ratio of 4:6, and placed in a planetary vacuum degassing machine. During the mixing process, premixing was performed at 200 rpm for 5 minutes to initially disperse the fibers in the resin. Then, the rotation speed was increased to 800 rpm, and the vacuum mode was activated to reduce the system vacuum to below 100 Pa, and mixing continued for 10 minutes. During the mixing process, the rotation direction was switched every 2 minutes to redistribute the filler under different flow field conditions.

[0068] After mixing, a mixture is obtained.

[0069] Step B: Curing and shaping: The mixture is injected into a mold, heated and pressurized to cure, thus obtaining a composite material.

[0070] The curing conditions were as follows: heating to 160°C at a rate of 5°C / min, pressure: 4.5MPa; holding time: 8 h, and then cooling to room temperature with the furnace.

[0071] Comparative Example 2 The difference from Example 1 is as follows: Without any pretreatment of the PTFE fiber bundles, the raw fibers were directly mixed with the bismaleimide matrix at a mass ratio of 4:6 as filler. The mixture was stirred at atmospheric pressure using a conventional high-shear mixer (JRJ300-SH high-shear emulsifying disperser) at a speed of 2000 rpm with a 70 mm working head. The stirring time was 2 hours, without vacuum impregnation. After mixing, step (4) was performed, which was the same as in Example 1.

[0072] Comparative Example 3 The difference from Example 1 is as follows: Step (2) involves surface modification of PTFE fibers using graphdiyne nanosheets and an ionic solution (1-butyl-3-methylimidazolium tetrafluoroborate), without the addition of covalent organic framework nanosheets.

[0073] Step (2) specifically involves mixing the irradiated fibers from step (1) with graphyne nanosheets and an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) at a mass ratio of 100:2:1, and adding zirconia balls at a ball-to-material ratio of 20:1. The resulting mixture is then placed in a Teflon container and ball-milled for 2 hours at 250 rpm using a planetary vacuum degassing machine, achieving self-assembly and encapsulation of the two-dimensional nanomaterials under mechanical shearing. The ball-milled material is then passed through a 200-mesh sieve to obtain a surface-modified filler.

[0074] The remaining steps are the same as in Example 1.

[0075] Performance characterization and data comparison: The surface morphology of the composite material samples obtained in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were observed using an optical microscope, and their compressive strength and strain were tested to characterize the material structure and mechanical properties.

[0076] Test item description: Compressive strength test: conducted according to GB / T 1041-2008, using a 5 mm * 10 mm * 10 mm cube specimen. Before testing, the specimen was conditioned to the standard environment for at least 24 hours as specified in GB / T 2918. Then, the specimen was tested on a universal testing machine conforming to GB / T 17200. The testing machine applied a load to the specimen at a constant rate of 2 mm / min until the specimen failed or the deformation rate reached 50%, at which point the test was stopped, and the pressure-deformation rate curve was recorded during the test.

[0077] Friction Testing: The tribological properties of the composite material were evaluated using a ring-block contact pair on a Platt surface contact testing machine. The upper specimen was a bearing steel ring, and the lower specimen was a composite material liner bonded to a mold. The test conditions were: load 5 kN, rotation speed 40 rpm, and duration 0.5 hours. The change in the coefficient of friction (COF) was recorded during the test to provide a simple assessment of wear.

[0078] The test results are shown in Table 1 below.

[0079] Table 1

[0080] Results analysis: Based on the data in Table 1, microscopic observation results, and test images (refer to...), Figure 2-4As can be seen, compared with the three comparative examples, the composite material prepared in Example 1 of this application has a more uniform and dense surface, a significantly reduced number of internal pores and defects, and better overall material structure consistency. Simultaneously, its compressive strength (125 MPa) and compressive strain (9.7%) are both optimal. Regarding the comparison of frictional performance, throughout the entire test period, the coefficient of friction of Example 1 remained consistently in the extremely low range of 0.035~0.040, with minimal fluctuations, and an average COF of only 0.043, demonstrating excellent long-term lubrication stability.

[0081] Although the composite material in Comparative Example 1 was also vacuum-mixed, the lack of a surface interface layer resulted in inferior wetting of the fiber (filler) and resin compared to Example 1. Defects in the internal structure of the composite material led to poor compressive strength and lubrication, with the compressive strength decreasing from 125 MPa to 86.5 MPa and the average coefficient of friction increasing to 0.090. This demonstrates that a vacuum environment alone cannot completely solve the wetting problem of high-viscosity resin. Without a surface interface layer, the bonding force between the filler and the matrix is ​​insufficient, and the lubricating filler cannot function effectively, resulting in significantly inferior mechanical and frictional properties compared to the examples.

[0082] The composite material in Comparative Example 2, prepared using conventional processes, exhibited a compressive strength of only 63.9 MPa, the most surface defects, and a continuously increasing coefficient of friction with prolonged testing time, eventually reaching over 0.19, indicating significant lubrication failure. This demonstrates that simple dispersing and conventional mixing not only fail to solve the dispersion and wetting problems but also result in structural defects that severely degrade tribological properties.

[0083] Comparative Example 3 used only graphyne nanosheets and ionic liquid to modify the surface of the fibers. The results showed that the filler distribution in this system was relatively uniform, but a small number of pore defects still existed. Its compressive strength was 106.4 MPa, slightly lower than that of Example 1 (125 MPa). Although the average friction coefficient of the composite material in Comparative Example 3 was only 0.072, higher than that of this application (0.043), the friction curve was relatively stable during the test, significantly better than the unmodified fiber system, indicating that graphyne and ionic liquid can form a stable lubricating interface layer. However, due to the disruption of the special synergy between the network framework nanosheets, the two-dimensional lubricating nanomaterials, and the ionic liquid, and the lack of resin transport channels constructed by the network framework structure, the high-viscosity resin wetting and interface effect in this system were still limited, resulting in some structural defects and making it difficult to fully utilize the lubricating components. Therefore, it can be seen that by introducing a network framework nanosheet combined with two-dimensional lubricating nanomaterials and ionic liquids, this application can further improve the resin wetting and interfacial bonding effects, and achieve a simultaneous improvement in compressive strength and lubrication effect, indicating that the three have a significant synergistic effect.

[0084] In summary, this application effectively improves the interfacial bonding effect between fillers and high-viscosity resins such as bismaleimide by constructing a surface interface gradient structure through the synergistic effect of three components and combining it with an integrated process. This reduces internal defects and significantly improves long-term lubrication stability, thereby achieving a synergistic improvement in the mechanical and tribological properties of the composite material.

[0085] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.

Claims

1. A packing material, characterized in that, It includes the following components: fibers, mesh framework nanosheets, two-dimensional lubricating nanomaterials, and ionic liquids; The fiber includes fluorinated fiber; The network framework nanosheets include covalent organic framework nanosheets; The two-dimensional lubricating nanomaterial includes graphynylene; The mass ratio of the fiber, the mesh framework nanosheet, the two-dimensional lubricating nanomaterial, and the ionic liquid is 100:(1~10):(0.5~5):(0.1~2); The method for preparing the filler includes the following steps: The fibers undergo a pretreatment to regularize their structure; the pretreatment to regularize their structure includes a pre-irradiation treatment. The processed fibers, the mesh framework nanosheets, the two-dimensional lubricating nanomaterials, and the ionic liquid are mechanically mixed to obtain a filler. The mechanical mixing is carried out by ball milling.

2. The packing material according to claim 1, characterized in that, The ionic liquid includes imidazole ionic liquids.

3. A method for preparing the filler according to any one of claims 1 to 2, characterized in that, Includes the following steps: The fibers undergo a pretreatment to regularize their structure; the pretreatment to regularize their structure includes a pre-irradiation treatment. The processed fibers, the mesh framework nanosheets, the two-dimensional lubricating nanomaterials, and the ionic liquid are mechanically mixed to obtain a filler. The mechanical mixing is carried out by ball milling.

4. The method for preparing the filler according to claim 3, characterized in that, The ball milling conditions are: rotation speed: 100~300 rpm; time: 2~3 h; ball-to-material ratio: 10:1~30:

1.

5. The method for preparing the filler according to claim 3, characterized in that, The pretreatment for structural regularization also includes one or more of the following: mechanical dispersing, sieving, and drying.

6. A high-viscosity resin-based self-lubricating composite material, characterized in that, Includes fillers and resin matrix; The packing material is the packing material according to any one of claims 1-2 or the packing material prepared by any one of claims 3-5.

7. The high-viscosity resin-based self-lubricating composite material according to claim 6, characterized in that, The resin matrix is ​​one or a mixture of two of bismaleimide and cyanate ester-bismaleimide copolymer; The filler content is 20~60 wt.%.

8. A method for preparing a high-viscosity resin-based self-lubricating composite material according to any one of claims 6-7, characterized in that, Includes the following steps: The filler and the resin matrix are mixed in a vacuum environment to obtain a mixture; After the mixture is cured and molded, a high-viscosity resin-based self-lubricating composite material is obtained.

9. The method for preparing the high-viscosity resin-based self-lubricating composite material according to claim 8, characterized in that, In the vacuum environment, the vacuum level is below 200 Pa; When the filler and the resin matrix are mixed in a vacuum environment, a staged mixing method is adopted, starting with low speed and then increasing to high speed.

10. The method for preparing the high-viscosity resin-based self-lubricating composite material according to claim 8, characterized in that, The curing conditions for the curing molding are as follows: heating to 160±10℃ at a rate of 3~6℃ / min, pressure: 3 MPa~6 MPa; heat and pressure holding time: 6 h~12 h.

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