Polymer material for intelligent self-lubricating plain bearing and method for producing and using the same

Abstract

The application discloses a preparation method of a polymer material for an intelligent self-lubricating joint bearing, and comprises the following steps: 1) preparing a conductive core-shell structure; 2) surface modification of conductive-lubricating synergistic fillers; 3) preparing a phenolic resin diluent; 4) adding the conductive core-shell structure fillers and the modified conductive-lubricating synergistic fillers into the phenolic resin diluent to obtain modified phenolic resin slurry through dispersion; 5) coating the slurry to prepare a modified phenolic resin adhesive film; and 6) stacking the adhesive film to form a multilayer structure and preparing the polymer material for the intelligent self-lubricating joint bearing. The application constructs an integrated structure of "surface layer friction-reducing lubrication-bottom layer conductive early warning", when the friction-reducing lubrication layer is worn to a specific depth and the conductive early warning layer is exposed, the conductivity of the system will change in steps, and the accurate determination and early warning of the wear degree are realized.

Description

Technical Field

[0001] This invention belongs to the field of intelligent self-lubricating composite material technology, specifically relating to a method for preparing polymer materials for intelligent self-lubricating spherical bearings and their applications. Background Technology

[0002] Self-lubricating spherical bearings are core load-bearing and moving components in the landing gear, aerodynamic control surfaces, and rotor systems of fixed-wing aircraft, and their service reliability is directly related to flight safety. However, under long-term alternating loads, the cumulative wear of bearings can lead to excessive clearance or functional failure, which can easily cause mechanical system malfunctions or even catastrophic accidents. Currently, the assessment of their wear condition in engineering still mainly relies on offline inspection methods such as "periodic shutdown and manual intervention" (e.g., measuring clearance with feeler gauges or disassembly inspection). This type of passive maintenance is not only inefficient and prone to human error, but the disassembly and assembly process may also cause secondary damage. On the other hand, although methods such as embedded sensing and self-powered sensing have been proposed, their reliance on external sensors significantly increases the added weight and structural complexity of the system, and does not fully consider the friction and wear properties of materials, making it difficult to meet the stringent requirements of next-generation aerospace equipment for lightweight design, high intrinsic reliability, and maintenance-free characteristics.

[0003] Existing technologies, such as patent documents CN118667206A ("Polyetherimide-based Conductive Self-lubricating Polymer and its Preparation Method and Application") and CN120795700A ("A Wear Early Warning Smart Material Based on Conductive Core-Shell Micro / Nano Particles and its Preparation Method"), utilize the resistance / current changes during friction to achieve wear failure early warning by constructing a multi-layered gradient polymer structure. Regarding the pad structure, CN119755201A ("A Smart Self-Lubricating Pad for Wear Monitoring") proposes a segmented embedded design, while CN118727448A ("A Smart Self-Lubricating Pad Preparation Method and Application") and CN118422504A ("A Smart Self-Lubricating Pad and its Preparation Method") employ a gradient impregnation layered structure. All of these technical solutions explore intelligent monitoring paths based on conductive properties, laying the foundation for state sensing technology for self-lubricating spherical bearings.

[0004] However, existing technical solutions still have the following key problems that need to be solved in practical applications: 1) Existing research focuses on the functional realization of fabric pads and lacks the development of polymer material systems; 2) Although existing technologies can achieve certain wear monitoring functions, they fail to take into account the tribological performance; 3) The compatibility problem between conductive fillers and the matrix has not been effectively solved. The weak interfacial bonding effect leads to a simultaneous decline in the mechanical and tribological properties of composite materials, which to some extent restricts their engineering application in the high-load, long-life, and harsh working conditions of aerospace. Summary of the Invention

[0005] This invention aims to solve the technical problems related to wear condition assessment of self-lubricating spherical bearings, and provides a method for preparing polymer materials for intelligent self-lubricating spherical bearings. This polymer material, while maintaining a low coefficient of friction, can establish a real-time mapping relationship between wear progress and resistance / conductivity signals, achieving an integrated design of "structure-function-sensing". The polymer material provided by this invention effectively overcomes the technical drawback of traditional self-lubricating spherical bearings, which require shutdown or disassembly for wear detection.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for preparing a polymer material for a smart self-lubricating spherical bearing, comprising the following steps: 1) Conductive monomers are oxidized and polymerized on the surface of a solid lubricant to obtain a conductive core-shell structure filler; 2) Surface modification of the conductive-lubricating synergistic filler was performed to obtain the modified conductive-lubricating synergistic filler; 3) Mix phenolic resin, anhydrous ethanol, and ethyl acetate in a certain proportion to obtain a diluted phenolic resin solution; 4) The conductive core-shell structure filler and the modified conductive-lubricating synergistic filler are added to the phenolic resin diluent in a certain ratio and dispersed evenly to obtain a series of modified phenolic resin slurries; 5) The modified phenolic resin slurry is coated with a coating machine to form a film of the required thickness, and then dried and cured to obtain a modified phenolic resin film. 6) The prepared phenolic resin film is stacked to form a multilayer structure, thus obtaining a polymer material for intelligent self-lubricating spherical bearings.

[0007] In some specific embodiments, the oxidative polymerization of conductive monomers on the surface of the solid lubricant in step 1) specifically involves: adding conductive monomers and oxidants to a suspension of solid lubricant under low temperature conditions, stirring evenly, and then carrying out an in-situ oxidative polymerization reaction, followed by washing and drying to obtain a conductive core-shell structure filler.

[0008] Further, the step of oxidative polymerization of conductive monomers on the surface of the solid lubricant is as follows: 1-5g of solid lubricant powder is dispersed in 100-200mL of organic solvent, 0.1-0.5mL of conductive monomer is added and ultrasonically dispersed; under ice-water bath conditions of -25~0℃, 5-15mL of 0.05-0.15M oxidant solution is slowly added dropwise to initiate the polymerization reaction, and the reaction is maintained for 8-12h; after the reaction is completed, the mixture is washed with anhydrous ethanol and vacuum dried at 80-100℃ for 8-12h to obtain a conductive core-shell structure filler.

[0009] In some specific embodiments, the solid lubricant is one or more of polytetrafluoroethylene, polyetheretherketone, nylon, or polyimide.

[0010] The solid lubricant has a particle size of 100 nm to 20 μm.

[0011] The dispersant used in the suspension of the solid lubricant is one or more of water, methanol, ethanol or acetone.

[0012] In some specific embodiments, the conductive monomer is one or more of pyrrole, aniline, thiophene, or acetylene, and the oxidant is one of ferric chloride or ammonium persulfate.

[0013] In some specific embodiments, the conductive-lubricating synergistic filler in step 2) is one or more of graphene, carbon nanotubes, Mxene, molybdenum disulfide, tungsten disulfide, or tungsten diselenide.

[0014] In some specific embodiments, the surface modification of the conductive-lubricating synergistic filler in step 2) specifically involves dispersing the conductive-lubricating synergistic filler in an organic solvent and performing ultrasonic exfoliation, followed by adding a silane coupling agent for modification to obtain the modified conductive-lubricating synergistic filler.

[0015] The organic solvent mentioned above is N-methylpyrrolidone; The modified process parameters are reflux at 50-70℃ for 2-6 hours; The silane coupling agent has a mass concentration of 0.5-1.5 wt%, and the silane coupling agent is one or more of KH-550, KH-560, or KH-570.

[0016] In some specific embodiments, the mass ratio of phenolic resin, anhydrous ethanol, and ethyl acetate in the phenolic resin diluent in step 3) is (2-4):1:1.

[0017] In some specific embodiments, the mass ratio of the conductive core-shell structure filler and the modified conductive-lubricating synergistic filler in step 4) is 1:(1-2).

[0018] In some specific embodiments, the total amount of conductive core-shell structure filler and modified conductive-lubricating synergistic filler added in step 4) is 0-20% of the phenolic resin diluent.

[0019] In some specific embodiments, the total amount of conductive core-shell structure filler and modified conductive-lubricating synergistic filler added in step 4) is 5-15% of the phenolic resin diluent.

[0020] In some specific embodiments, the thickness of the modified phenolic resin film in step 5) is 500-1000µm.

[0021] As part of the same inventive concept, this invention provides a polymer material for intelligent self-lubricating spherical bearings prepared by the aforementioned preparation method.

[0022] As part of the same inventive concept, this invention provides the application of the aforementioned polymer material for intelligent self-lubricating spherical bearings as a self-lubricating material.

[0023] Compared with the prior art, the present invention has at least the following advantages: 1) This invention employs an in-situ polymerization method, using ferric chloride to oxidize pyrrole monomers under 0°C ice-water bath conditions, and uniformly generating a polypyrrole coating layer on the surface of polytetrafluoroethylene after 6 hours of reaction; this low-temperature synthesis strategy effectively ensures the uniformity and density of the coating layer, avoiding the particle agglomeration problem that is easily caused by traditional high-temperature polymerization; at the same time, a conductive core-shell structure filler is prepared, which effectively combines the excellent low-friction characteristics of solid lubricants with the high conductivity of conductive monomers.

[0024] 2) This invention constructs a binary synergistic system of conductive core-shell structured filler PPy@PTFE and modified conductive-lubricating synergistic filler WS2. By adjusting the composite ratio of the two, the spatial complementary distribution of "spherical core-shell particles-layered sheets" at the microscale is utilized to realize the "double percolation effect" of the conductive network and the "two-phase synergistic effect" of the lubrication network.

[0025] 3) This invention constructs an integrated two-layer structure of "surface friction-reducing lubrication - bottom conductive warning": the friction-reducing lubrication layer utilizes the synergistic effect of the WS2 and PPy@PTFE core-shell structure to ensure excellent self-lubricating performance (friction coefficient stably maintained below 0.15); the conductive warning layer constructs a complete conductive path by optimizing the ratio of PPy@PTFE and WS2; when the friction-reducing lubrication layer is worn down to a certain depth, exposing the conductive warning layer, the conductivity of the bearing system will undergo a significant step change; this signal change can be captured in real time by conventional electrical measurement devices, thereby achieving accurate judgment and warning of the degree of wear. This design achieves the integration of "structure-function-sensing", effectively overcoming the structural complexity and reliability risks introduced by traditional external sensors in existing technologies.

[0026] 4) This invention significantly improves the bonding strength between PPy@PTFE core-shell structure and WS2 by optimizing the addition ratio (total addition not exceeding 20wt% of phenolic resin diluent) and by using a silane coupling agent to modify the surface of WS2. Simultaneously, the excellent high-temperature resistance and aging resistance of phenolic resin itself enable this intelligent self-lubricating polymer material to adapt to a wide temperature range of -50℃ to 200℃ and complex engineering environments such as humidity and dust, ensuring the stability of monitoring signals and the reliability of material performance during long-term service.

[0027] 5) The preparation method provided by this invention covers all stages from resin matrix dilution, core-shell structure synthesis, filler functionalization modification, to composite slurry preparation and film coating and curing. All stages are based on conventional chemical equipment and mature, controllable process parameters (such as ultrasonic dispersion, mechanical stirring, vacuum degassing, and segmented curing). This process route is simple to operate and possesses extremely high standardization potential and feasibility for large-scale production. Furthermore, the selected raw materials are all commonly used industrial materials, with controllable costs and wide availability. The technical solution does not rely on expensive rare elements or demanding complex synthesis methods, thereby effectively reducing the overall manufacturing cost and laying a solid economic foundation for the large-scale industrial promotion of this material. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0029] Figure 1 The SEM morphology and FTIR results of the conductive core-shell structure provided in Embodiment 1 of the present invention are shown. in: Figure 1 (a) is a SEM image of the conductive core-shell structure PTFE provided in Embodiment 1 of the present invention; Figure 1 (b) is a SEM image of the conductive core-shell structure PPy@PTFE provided in Embodiment 1 of the present invention; Figure 1 (c) is a SEM image of the conductive core-shell structure PPy@PTFE after it has been broken according to Embodiment 1 of the present invention; Figure 1 (d) is the FTIR result of the conductive core-shell structure PPy@PTFE provided in Embodiment 1 of the present invention; Figure 2 The friction coefficient and conductivity variation curves of the modified phenolic resin films provided in Embodiment 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention are shown. in: Figure 2(a) Curves showing the change in friction coefficient and electrical conductivity of modified phenolic resin films with different proportions of PPy@PTFE-WS2 added, provided in Example 1 of the present invention; Figure 2 (b) The friction coefficient and conductivity variation curves of the modified phenolic resin films with different proportions of PPy@PTFE added, provided in Comparative Example 1 of the present invention; Figure 2 (c) The friction coefficient and conductivity variation curves of the modified phenolic resin films with different proportions of WS2 added, provided in Comparative Example 2 of the present invention; Figure 2 (d) is the friction coefficient and conductivity variation curve of the modified phenolic resin film with different proportions of PPy / PTFE-WS2 provided in Comparative Example 3 of the present invention. Figure 3 The friction coefficient and conductivity variation curves of the polymer material for intelligent self-lubricating spherical bearings provided in Embodiment 1 of the present invention during a friction experiment; Figure 4 The friction coefficient and conductivity change curves of the polymer material for intelligent self-lubricating spherical bearings provided in Embodiment 2 of the present invention during a friction experiment; Figure 5 The friction coefficient and conductivity change curves of the polymer material for intelligent self-lubricating spherical bearings provided in Embodiment 3 of the present invention during a friction experiment; Figure 6 This is a schematic diagram illustrating the intelligent monitoring principle of the polymer material used in intelligent self-lubricating spherical bearings according to the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0031] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0032] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0033] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0034] Unless otherwise specified, all raw materials used in the following embodiments and experiments are commercially available.

[0035] In the following embodiments, the triboelectric conductivity test is specifically performed as follows: GCr15 is selected as the upper sample, and 45 steel is used to make the lower sample. A modified phenolic resin film is bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the modified phenolic resin film lower sample for testing; or the modified phenolic resin film is stacked to form a multilayer structure to obtain a polymer material for intelligent self-lubricating spherical bearings, which is then bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the polymer material lower sample for testing. The lower sample is tested using a screen-display end-face friction and wear testing machine at room temperature, with a load of 500N and a sliding speed of 0.36m / s. At the same time, a multimeter is used to measure the change in resistance of the intelligent self-lubricating film in real time.

[0036] Example 1

[0037] This embodiment provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings, comprising the following steps: 1) Fabrication of PPy@PTFE conductive core-shell structure 3 g of polytetrafluoroethylene (PTFE) with an average particle size of 15 μm was ultrasonically dispersed in 150 mL of anhydrous ethanol to obtain a homogeneous suspension. Then, 0.3 mL of conductive pyrrole monomer was added and ultrasonically dispersed again. Under 0°C ice-water bath conditions, 10 mL of 0.15 M ferric chloride aqueous solution was slowly added dropwise to initiate the polymerization reaction. The pyrrole (Py) monomer underwent in-situ oxidative polymerization on the PTFE surface for 6 h to form a conductive PPy coating layer. The product was washed with ethanol and vacuum dried at 80°C for 12 h to obtain a conductive core-shell structured filler (PPy@PTFE). The SEM and FTIR results of the prepared conductive core-shell structured filler are shown below. Figure 1 ; 2) WS2 surface modification 10g of two-dimensional layered conductive-lubricating synergistic filler tungsten disulfide (WS2) powder was ultrasonically exfoliated in 100mL of N-methylpyrrolidone (NMP) for 1 h; 100mL of KH-570 with a mass concentration of 1.5wt.% was added, and the mixture was refluxed at 50℃ for 2 h to obtain modified WS2. 3) Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 5% and 7.5% of PPy@PTFE and modified WS2 at a mass ratio of 1:1 were added to the phenolic resin diluent, respectively. The mixture was first sonicated and then stirred. After vacuum degassing, a uniformly dispersed modified phenolic resin slurry was obtained. This slurry was then coated using a coating machine to prepare a modified phenolic resin film with a thickness of 950µm. 4) Preparation of test samples A modified phenolic resin film with 5% PPy@PTFE and WS2 added to a phenolic resin diluent and a modified phenolic resin film with 7.5% PPy@PTFE and WS2 added to a phenolic resin diluent were bonded together with an adhesive (modified phenolic resin adhesive) to obtain an integrated multi-layer structure of "friction-reducing lubrication layer-conductive warning layer", which is a polymer material used for intelligent self-lubricating spherical bearings. The intelligent polymer material was bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the lower sample of the intelligent polymer material for testing.

[0038] This embodiment conducts triboelectric conductivity tests on the friction coefficient and conductivity of modified phenolic resin films containing different mass proportions of PPy@PTFE and modified WS2. The results are as follows: Figure 2 As shown in (a), the friction coefficient and conductivity of the smart polymer material sample were tested using a triboelectric conductivity method, and the results are as follows. Figure 3 As shown.

[0039] Comparative Example 1 This comparative example provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings. The components and proportions are basically the same as in Example 1, except that modified WS2 is not added. The method for preparing conductive core-shell structure filler PPy@PTFE and phenolic resin films containing different mass percentages of PPy@PTFE is the same as in Example 1, specifically: 1) Fabrication of PPy@PTFE conductive core-shell structure 3 g of polytetrafluoroethylene (PTFE) with an average particle size of 15 μm was ultrasonically dispersed in 150 mL of anhydrous ethanol to obtain a homogeneous suspension. Then, 0.3 mL of conductive pyrrole monomer was added and ultrasonically dispersed again. Under ice-water bath conditions at 0 °C, 10 mL of 0.15 M ferric chloride aqueous solution was slowly added dropwise to initiate the polymerization reaction. The pyrrole (Py) monomer underwent in-situ oxidative polymerization on the PTFE surface for 6 h to form a conductive PPy coating layer. The product was washed with ethanol and vacuum dried at 80 °C for 12 h to obtain a conductive core-shell structure filler (PPy@PTFE). 2) Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 0-20% PPy@PTFE was added to the phenolic resin diluent, followed by ultrasonication and stirring. After vacuum degassing, a uniformly dispersed modified phenolic resin slurry was obtained. This slurry was then coated using a coating machine to prepare a modified phenolic resin film with a conductive core-shell structure filler content of 0-20% of the phenolic resin diluent and a thickness of 950µm. 3) Preparation of test samples Phenolic resin films modified with PPy@PTFE at different mass ratios (0-20%) were bonded to the surface of the lower sample and cured at 120℃ for 1 hour to obtain the lower sample of the modified phenolic resin film.

[0040] This comparative example tested the friction coefficient and conductivity of phenolic resin films containing different mass percentages (0-20%) of PPy@PTFE. The results are as follows: Figure 2 As shown in (b).

[0041] Comparative Example 2 This comparative example provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings. The composition and proportions are basically the same as in Example 1, except that the PPy@PTFE conductive core-shell structure is not added. Modified conductive-lubricating synergistic filler WS2 and modified phenolic resin films containing different mass percentages of modified WS2 are prepared. The process steps and parameters are the same as in Example 1, specifically: 1) WS2 surface modification 10g of two-dimensional layered conductive-lubricating synergistic filler tungsten disulfide (WS2) powder was ultrasonically exfoliated in 100mL of N-methylpyrrolidone (NMP) for 1 h; 100mL of KH-570 with a mass concentration of 1.5wt.% was added, and the mixture was refluxed at 50℃ for 2 h to obtain modified WS2. 2) Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 0-20% modified WS2 was added to the phenolic resin diluent, followed by ultrasonication and stirring. After vacuum degassing, a uniformly dispersed modified phenolic resin slurry was obtained. This slurry was then coated using a coating machine to prepare a phenolic resin film with a thickness of 950µm, containing 0-20% modified WS2 in the phenolic resin diluent. 3) Preparation of test samples Modified phenolic resin films of WS2 with different mass percentages (0-20%) were bonded to the surface of the lower sample and cured at 120℃ for 1 hour to obtain the lower sample of modified phenolic resin film.

[0042] This comparative example tested the friction coefficient and conductivity of modified phenolic resin films containing different mass percentages (0-20%) of modified WS2. The results are as follows: Figure 2 As shown in (c).

[0043] Comparative Example 3 This comparative example provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings. The composition and proportions are basically the same as in Example 1, except that a PPy@PTFE conductive core-shell structure is not prepared; instead, polypyrrole and polytetrafluoroethylene are directly added to the system. The process steps and parameters are the same as in Example 1, specifically: 1) WS2 surface modification 10g of two-dimensional layered conductive-lubricating synergistic filler tungsten disulfide (WS2) powder was ultrasonically exfoliated in 100mL of N-methylpyrrolidone (NMP) for 1 h; 100mL of KH-570 with a mass concentration of 1.5wt.% was added, and the mixture was refluxed at 50℃ for 2 h to obtain modified WS2. 2) Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 0-20% of PPy, PTFE, and modified WS2 (hereinafter referred to as PPy / PTFE-WS2, where the mass ratio of PPy to PTFE is 3:7) were added to the phenolic resin diluent. The mixture was first sonicated and then stirred. After vacuum degassing, a uniformly dispersed modified phenolic resin slurry was obtained. This slurry was then coated using a coating machine to prepare a modified phenolic resin film with a thickness of 950µm, in which the amount of PPy / PTFE-WS2 added was 0-20% of the phenolic resin diluent. 3) Preparation of test samples Different mass percentages (0-20%) of PPy / PTFE-WS2 modified phenolic resin films were bonded to the surface of the lower sample and cured at 120℃ for 1 hour to obtain the modified phenolic resin film lower sample.

[0044] This comparative example tested the friction coefficient and conductivity of phenolic resin films containing different mass percentages (1-20%) of PPy / PTFE-WS2. The results are as follows: Figure 2 As shown in (d).

[0045] Example 2

[0046] This embodiment provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings, comprising the following steps: 1. Fabrication of PANI@PTFE conductive core-shell structure 5 g of polytetrafluoroethylene (PTFE) with an average particle size of 15 μm was ultrasonically dispersed in 100 mL of acetone to obtain a uniform suspension. Under 0°C ice-water bath conditions, 10 mL of 0.10 M ferric chloride aqueous solution was slowly added dropwise to initiate the polymerization reaction. Aniline monomers underwent in-situ oxidative polymerization on the PTFE surface for 6 h to form a conductive polyaniline (PANI) coating layer. The product was washed with ethanol and vacuum dried at 80°C for 12 h to obtain a conductive core-shell structure filler (PANI@PTFE). 2. WS2 Surface Modification 10g of two-dimensional layered conductive-lubricating synergistic filler tungsten disulfide (WS2) powder was ultrasonically exfoliated in 100mL of N-methylpyrrolidone (NMP) for 1 h; 100mL of KH-570 with a mass concentration of 1.5wt.% was added, and the mixture was refluxed at 50℃ for 2 h to obtain modified WS2. 3. Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 5% and 7.5% of PANI@PTFE and modified WS2 at a mass ratio of 1:2 were added to the phenolic resin diluent. The mixture was first sonicated and then stirred. After vacuum degassing, a uniformly dispersed modified phenolic resin adhesive was obtained. This adhesive was then coated using a coating machine to prepare a phenolic resin film with a thickness of 950µm, containing 5% and 7.5% of the phenolic resin diluent, respectively, of conductive core-shell structure filler and modified conductive-lubricating synergistic filler. 4. Preparation of the test sample A modified phenolic resin film with 5% PANI@PTFE and WS2 added to a phenolic resin diluent and a modified phenolic resin film with 7.5% PANI@PTFE and WS2 added to a phenolic resin diluent were bonded together with an adhesive (modified phenolic resin adhesive) to obtain an integrated multilayer structure of "friction-reducing lubrication layer-conductive warning layer", which is a polymer material used for intelligent self-lubricating spherical bearings. The intelligent polymer material was bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the lower sample of the intelligent polymer material for testing.

[0047] This embodiment conducts triboelectric conductivity tests on the friction coefficient and conductivity of samples made of smart polymer materials. The results are as follows: Figure 4 As shown.

[0048] Example 3

[0049] This embodiment provides a method for preparing a polymer material for intelligent self-lubricating spherical bearings, comprising the following steps: 1. Preparation of PANI@PEEK core-shell structure 3g of polyetheretherketone (PEEK) powder with an average particle size of 200nm was ultrasonically dispersed in 100mL of anhydrous ethanol to obtain a uniform suspension. Under ice-water bath conditions at -25℃, 9mL of 0.1M ferric chloride aqueous solution was slowly added dropwise to initiate the polymerization reaction. Aniline monomers underwent in-situ oxidative polymerization on the PEEK surface for 6 h to form a conductive polyaniline (PANI) coating layer. The product was washed with ethanol and vacuum dried at 80℃ for 12 h to obtain a conductive core-shell structure filler (PANI@PEEK). 2. Surface modification of MoS2 10g of two-dimensional layered conductive-lubricating synergistic filler molybdenum disulfide (MoS2) powder was ultrasonically exfoliated in 100mL of N-methylpyrrolidone (NMP) for 1 h; 100mL of KH-570 with a mass concentration of 1.0wt.% was added, and the mixture was refluxed at 50℃ for 2 h to obtain modified MoS2. 3. Preparation of matrix solution and preparation of film A phenolic resin diluent was prepared by diluting phenolic resin, ethyl acetate, and anhydrous ethanol at a mass ratio of 4:1:1. 5% and 7.5% of PANI@PEEK and modified MoS2 at a mass ratio of 1:1 were added to the phenolic resin diluent, respectively. The mixture was first sonicated and then stirred. After vacuum degassing, a uniformly dispersed modified phenolic resin slurry was obtained. This slurry was then coated using a coating machine to prepare a phenolic resin film with a thickness of 950µm, containing a total addition of 5% and 7.5% of the phenolic resin diluent for conductive core-shell structure filler and modified conductive filler, respectively. 4. Preparation of the test sample A modified phenolic resin film with 5% PANI@PEEK and modified MoS2 added to a phenolic resin diluent and a modified phenolic resin film with 7.5% PANI@PEEK and modified MoS2 added to a phenolic resin diluent were bonded together with an adhesive (modified phenolic resin adhesive) to obtain an integrated multilayer structure of "friction-reducing lubrication layer-conductive warning layer", which is a polymer material used for intelligent self-lubricating spherical bearings. The intelligent polymer material was bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the lower sample of the intelligent polymer material for testing.

[0050] This embodiment conducts triboelectric conductivity tests on the friction coefficient and conductivity of samples made of smart polymer materials. The results are as follows: Figure 5 As shown.

[0051] Performance characterization and testing 1) Identification of conductive core-shell structure filler products This test uses Example 1 as an example to perform morphological and elemental analysis on the prepared conductive core-shell structure filler (PPy@PTFE) and core material polytetrafluoroethylene (PTFE). The SEM images and FTIR spectra are shown below. Figure 1 As shown in the figure, Figure 1 The surface morphology and compositional analysis results of PTFE, the complete PPy@PTFE core-shell structure, and the fragmented PPy@PTFE core-shell structure are presented respectively. Figure 1 As shown in (a), the PTFE surface is rough and irregular; energy dispersive spectroscopy (EDS) results indicate that its main elements are C, F and Au (where Au is derived from the gold sputtering treatment before sample observation). Figure 1(b) Scanning electron microscopy (SEM) characterization of the complete PPy@PTFE core-shell structure, whose main constituent elements include C, N, F, and Au; and Figure 1 (a) In contrast, N element originating from the shell material PPy was detected here; Figure 1 (c) shows the microstructure of the fragmented PPy@PTFE core-shell structure, where the exposed core material is mainly composed of C, F, and Au, consistent with the composition of pure PTFE; while the shell fragments are mainly composed of C, N, F, and Au, but with a relatively low F content. Figure 1 (b) The decrease indicates that the F element at this location originates from the residual PTFE core material.

[0052] 2) Test of changes in friction coefficient and conductivity a) Sample preparation for testing: This invention conducts triboelectric conductivity tests on the modified phenolic resin films and polymer materials for intelligent self-lubricating spherical bearings prepared in Examples 1-3 and Comparative Examples 1-3. Specifically, the modified phenolic resin film is bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the lower sample of the modified phenolic resin film for testing; or, modified phenolic resin films of different mass ratios are stacked to form a multilayer structure to obtain the polymer material for intelligent self-lubricating spherical bearings. The conductive warning layer of the intelligent polymer material is bonded to the surface of the lower sample and cured at 120°C for 1 hour to obtain the lower sample of the intelligent polymer material for testing. b) Testing methods The tribological properties of the specimens were tested using a screen-display end-face friction and wear testing machine at room temperature with a load of 500 N and a sliding speed of 0.36 m / s. At the same time, the resistance value of the intelligent self-lubricating adhesive film was measured in real time using a multimeter.

[0053] 3) Test Results This test used the modified phenolic resin films prepared in Examples 1-3 and Comparative Examples 1-3, and the polymer material used in the intelligent self-lubricating spherical bearing for triboelectric conductivity testing. The results are as follows: Figure 2 and Figure 3 As shown,; from Figure 2As can be seen from the data, in terms of conductivity, when PPy@PTFE is added alone (Comparative Example 1), the conductivity percolation threshold of the composite material appears at 20 wt%, and the material remains completely insulating before this concentration (<20 wt%). For the PPy@PTFE-WS2 (Example 1) synergistic system, when the PPy@PTFE content is fixed at 0 and the WS2 content is increased from 0 to 10 wt%, the system crosses the conductivity threshold at 10 wt% WS2. If PPy@PTFE is fixed at 2.5 wt%, only 5 wt% WS2 is needed to induce the formation of conductive pathways. Furthermore, as WS2 continues to increase to 10 wt% and 15 wt%, the conductivity shows a monotonically increasing trend. In contrast, for the PPy / PTFE-WS2 (Comparative Example 3) mechanically mixed system, within the experimental concentration range (total filler addition amount 0-20 wt%), the system remained in an insulating state regardless of the increase in total filler addition amount, and no conductivity percolation threshold was observed; for the WS2 single filler system (Comparative Example 2), an addition amount of 10 wt% was required to cross the conductivity threshold, and further increasing the WS2 content (> 10 wt%) had a limited effect on improving conductivity, with no significant increase. Regarding tribological properties, experimental results show that regardless of whether pure PPy@PTFE, PPy@PTFE-WS2, PPy / PTFE-WS2, or pure WS2 systems are used, their lubrication performance is improved to varying degrees compared to pure phenolic resin matrix. Among these, the control group with only WS2 added consistently maintained a friction coefficient higher than 0.20, showing some improvement compared to pure resin, but the improvement was limited. When the mass ratio of PPy@PTFE to WS2 was 1:1 and the total addition was 5 wt%, the average friction coefficient decreased significantly. In summary, regarding conductivity, the pure PPy@PTFE and PPy / PTFE-WS2 systems struggle to establish effective permeation pathways at low addition levels, and the modified phenolic resin film primarily exhibits insulating properties over a wide concentration window. While pure WS2 can trigger a conductivity shift at 10 wt%, the subsequent gain is weak. In contrast, the PPy@PTFE-WS2 synergistic filler system not only achieves an earlier conductivity threshold transition under low loads but also significantly improves tribological properties, successfully achieving both conductivity and friction reduction.

[0054] from Figure 3As can be seen, in the initial stage (before 4800s), the low-conductivity friction-reducing service layer completely covers the friction pair. At this time, the electrical signal at the friction interface maintains a high-resistance characteristic, and the grinding system is in a "healthy state." The average friction coefficient is maintained at 0.105 during this stage. As the service time increases, the friction-reducing service layer is gradually eroded. When the thickness drops to the critical value of about 4800s, the high-conductivity conductive warning layer is exposed, and the conductivity increases dramatically. The grinding system immediately switches to a "wear warning state," realizing the pre-diagnosis of lubrication failure. The intelligent monitoring principle diagram of the polymer material used for intelligent self-lubricating spherical bearings is shown below. Figure 6 As shown in the figure. This result demonstrates that the integrated polymer film self-lubricating layer of "friction-reducing and wear-resistant layer - conductive early warning layer" prepared in this invention can achieve precise monitoring and early warning of the wear process through abrupt changes in electrical conductivity.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for preparing a polymer material for intelligent self-lubricating spherical bearings, characterized in that, The steps include: 1) oxidizing and polymerizing conductive monomers on the surface of a solid lubricant to obtain a conductive core-shell structure filler; 2) Surface modification of the conductive-lubricating synergistic filler was performed to obtain the modified conductive-lubricating synergistic filler; 3) Mix phenolic resin, anhydrous ethanol, and ethyl acetate in a certain proportion to obtain a diluted phenolic resin solution; 4) The conductive core-shell structure filler and the modified conductive-lubricating synergistic filler are added to the phenolic resin diluent in a certain ratio and dispersed evenly to obtain a series of modified phenolic resin slurries; 5) The modified phenolic resin slurry is coated with a coating machine to form a film of the required thickness, and then dried and cured to obtain a modified phenolic resin film. 6) The prepared phenolic resin film is stacked to form a multilayer structure, thus obtaining a polymer material for intelligent self-lubricating spherical bearings.

2. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, The specific process of the oxidative polymerization of conductive monomers on the surface of the solid lubricant described in step 1) is as follows: Under low temperature conditions, conductive monomers and oxidants are added to the suspension of solid lubricant, stirred evenly, and then an in-situ oxidative polymerization reaction is carried out. After washing and drying, conductive core-shell structure filler is obtained.

3. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 2, characterized in that, The solid lubricant is one or more of polytetrafluoroethylene, polyetheretherketone, nylon, or polyimide.

4. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 2, characterized in that, The conductive monomer is one or more of pyrrole, aniline, thiophene, or acetylene, and the oxidant is one of ferric chloride or ammonium persulfate.

5. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, The conductive-lubricating synergistic filler mentioned in step 2) is one or more of graphene, carbon nanotubes, Mxene, molybdenum disulfide, tungsten disulfide, or tungsten diselenide.

6. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, Step 2) involves surface modification of the conductive-lubricating synergistic filler by ultrasonically exfoliating it in an organic solvent, followed by the addition of a silane coupling agent to obtain the modified conductive-lubricating synergistic filler.

7. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, In step 3), the mass ratio of phenolic resin, anhydrous ethanol, and ethyl acetate in the phenolic resin diluent is (2-4):1:

1.

8. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, In step 4), the mass ratio of conductive core-shell structure filler and modified conductive-lubricating synergistic filler in the modified phenolic resin slurry is 1:(1-2); the total amount of conductive core-shell structure filler and modified conductive-lubricating synergistic filler added in the modified phenolic resin slurry is 0-20% of the phenolic resin diluent.

9. The method for preparing the polymer material for intelligent self-lubricating spherical bearings according to claim 1, characterized in that, The thickness of the modified phenolic resin film described in step 5) is 500-1000µm.

10. A polymer material for intelligent self-lubricating spherical bearings prepared by the method according to any one of claims 1-9.

11. The application of the polymer material for intelligent self-lubricating spherical bearings according to claim 10 as a self-lubricating material.

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