A double-shell temperature-resistant solid-liquid synergistic lubrication microcapsule and a preparation method thereof

Abstract

The present application relates to the technical field of self-lubricating microcapsules, and discloses a double-shell temperature-resistant solid-liquid synergistic lubricating microcapsule and a preparation method thereof.The preparation method uses a polymer as a first shell material of the microcapsule, performs oil removal, roughening, sensitization and activation treatment on the single-shell polymer microcapsule, so that the surface of the single-shell polymer microcapsule presents a rough state, and a second composite plating layer is given to the surface of the single-shell polymer microcapsule through chemical plating, so that the prepared double-shell temperature-resistant solid-liquid synergistic lubricating microcapsule has high-temperature resistance and shell / core solid-liquid synergistic lubricating performance.The preparation method can meet the forming requirements of most polymer matrices, and the prepared double-shell temperature-resistant solid-liquid synergistic lubricating microcapsule has excellent compactness and tribological performance, and achieves the effect of lubrication and friction reduction.

Description

Technical Field

[0001] This invention relates to the technical field of self-lubricating microcapsules, and particularly to a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule and its preparation method. Background Technology

[0002] Microcapsules that hold lubricating oil have attracted significant research and industrial interest due to their ability to embed within polymer matrices, forming novel self-lubricating composite materials with ultra-low friction coefficients and wear rates. Inorganic hollow microspheres, porous microspheres, metal-organic frameworks, and polymer microcapsules are commonly used as microcapsules for storing lubricating oil, enabling automatic release of the oil within the polymer matrix. Microcapsules, as a typical example of microcapsules, offer advantages such as dense encapsulation and controllable oil storage, ensuring both durable and efficient lubrication. Common methods for preparing microcapsules include solution evaporation, interfacial polymerization, and in-situ polymerization. The core material of the microcapsule can be freely chosen, such as polyalphaolefin (PAO), silicone oil, liquid wax, and ionic liquids. However, due to limitations in the preparation principle, the outer shell material is often a polymer, such as polysulfone (PSF), polyurethane (PU), polymethyl methacrylate (PMMA), and polystyrene (PS). However, while existing polymer-shell microcapsules can achieve lubricant sealing, they are prone to melting and rupture under high-temperature operating conditions. Microcapsules prepared by inorganic hollow spheres have improved high-temperature and pressure resistance, but they have slightly poorer locking performance, and the inorganic shell is brittle and easily broken, and the shell material increases the coefficient of friction.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsule and its preparation method, aiming to solve the problems of existing polymer shell microcapsules being prone to softening and cracking at high temperatures and the shell material lacking lubricity.

[0005] Using polymer shell microcapsules as the basic material, a composite coating is applied to the surface of the polymer shell microcapsules through chemical composite plating, which enables the microcapsules to have high temperature resistance and lubrication properties in both the shell and the core, thus meeting the high temperature molding requirements of polymer shell materials and improving the lubrication performance of the microcapsules.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule includes the following steps:

[0008] S1. Preparation of single-shell polymer microcapsules: Single-shell polymer microcapsules are prepared by encapsulating lubricants with polymers;

[0009] S2. Pretreatment of single-shell polymer microcapsules: The single-shell polymer microcapsules are placed in an oil-removing solution for surface degreasing; the surface of the cleaned single-shell polymer microcapsules is roughened; the roughened single-shell polymer microcapsules are then subjected to sensitization and activation treatments in sequence.

[0010] S3. Form a second shell consisting of a metal-friction-reducing agent composite coating on the surface of the single-shell polymer microcapsule: Place the pretreated single-shell polymer microcapsule in a plating solution for chemical plating. After chemical plating, wash and dry to obtain a double-shell temperature-resistant solid-liquid synergistic lubricating microcapsule.

[0011] The method for preparing the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules, wherein the polymer in step S1 is one of PSF, PU, ​​PMMA, and PS.

[0012] The method for preparing the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules, wherein the decomposition temperature of the lubricant in step S1 is >350℃.

[0013] The method for preparing the double-shell temperature-resistant solid-liquid synergistic lubricating microcapsules, wherein the lubricant is one or more of PAO2, PAO4, PAO6, PAO8, PAO10, PAO40, and ionic liquids.

[0014] The method for preparing the double-shell heat-resistant solid-liquid synergistic lubricating microcapsules, wherein in step S2, 10g of the single-shell polymer microcapsules are added to an oil-removing solution composed of 40g-45g sodium hydroxide, 3g-5g degreasing agent and 500ml deionized water, and the solution is degreased at 60°C.

[0015] The method for preparing the double-shell heat-resistant solid-liquid synergistic lubricating microcapsules, wherein in the roughening treatment of step S2, the cleaned single-shell polymer microcapsules are added to a mixed solution consisting of 350ml-370ml concentrated sulfuric acid, 10g-13g potassium dichromate and 500ml deionized water, and roughened at 70℃-75℃ for 30min.

[0016] The method for preparing the double-shell heat-resistant solid-liquid synergistic lubricating microcapsules, wherein in step S2, the sensitization and activation treatments, involve adding the pretreated single-shell polymer microcapsules to a sensitization solution composed of 6g-8g stannous chloride, 10ml-12ml concentrated hydrochloric acid, and 200ml deionized water, sensitizing at 30℃-35℃ for 10min, and then washing with deionized water; adding the sensitized single-shell polymer microcapsules to an activation solution composed of 0.03g-0.05g palladium chloride, 2ml-4ml concentrated hydrochloric acid, and 200ml deionized water, activating at 30℃-35℃ for 10min, and then washing with deionized water.

[0017] The method for preparing the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules, wherein the plating solution in step S3 is one of Ni-P-PTFE plating solution, Cu-PTFE plating solution, Ni-P-MoS2 plating solution, Cu-MoS2 plating solution, Ni-P-Go plating solution, and Cu-Go plating solution.

[0018] The method for preparing the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules, wherein in step S3, the pretreated single-shell polymer microcapsules are placed in the plating solution at 50℃~85℃ for chemical plating for 30 minutes.

[0019] A dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule is prepared by the method described above. The dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule comprises a polymer shell, a lubricant core material encapsulated inside the polymer shell, and a second shell layer composed of a metal-friction-reducing agent composite coating on the surface of the polymer shell. The thermal weight loss temperature of the dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule is >350℃.

[0020] Beneficial effects:

[0021] This invention provides a double-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule and its preparation method. A single-shell polymer microcapsule is prepared using a polymer shell as the basic material. The single-shell polymer microcapsule is then subjected to degreasing, roughening, sensitization, and activation treatments to make the surface of the single-shell polymer microcapsule rough. A second shell layer, i.e., a composite coating, is then applied to the surface of the single-shell polymer microcapsule through chemical plating. This results in a double-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule that possesses high-temperature resistance and lubrication properties in both the shell and the core.

[0022] This method can ensure that the wall material rupture temperature of the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules is much higher than the decomposition temperature of the core material, which can meet the molding requirements of most polymers.

[0023] The double-shell, temperature-resistant solid-liquid synergistic lubricating microcapsules prepared by this method have excellent compactness, which can ensure that the single-shell polymer microcapsules are not damaged in polar / non-polar organic solvents.

[0024] The double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsules prepared by this method can enable polymer materials to obtain excellent tribological properties under high speed, heavy load and high temperature, and have excellent lubrication and friction reduction effects. Attached Figure Description

[0025] Figure 1 The SEM morphology of the samples from Example 1 and Comparative Example 1 is shown.

[0026] Figure 2This is the EDS elemental analysis diagram of Example 1.

[0027] Figure 3 The thermogravimetric analysis diagrams of each component in Example 1 are shown.

[0028] Figure 4 The macroscopic morphology of Examples 1-6 and Comparative Example 1 after sintering at 350°C for 30 min is shown. Detailed Implementation

[0029] This invention provides a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the scope of protection of the invention.

[0030] This invention provides a method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0031] (1) Preparation of single-shell PSF@lubricant microcapsules: 3-5g of PSF and 3-5g of lubricant were dissolved in 60-80ml of organic solvent (dichloromethane) to prepare an organic phase; 3-6g of gelatin were dissolved in 300ml of water to prepare a dispersed phase at a temperature of 30℃-35℃; the organic phase was added to 300ml of dispersed phase by mechanical stirring at 500-1000rpm. After addition, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, single-shell PSF@lubricant microcapsules were obtained through centrifugation, washing, and drying.

[0032] Specifically, the mass ratio of the polymer to the lubricant is (3-5):(3-5). Adjusting the lubricant content in the organic phase can control the core material content in the microcapsules. However, the lubricant content should not be too high, as this will reduce the stability of the system and decrease the encapsulation of the lubricant by the polymer PSF. The mass ratio of the lubricant to the polymer PSF should be controlled to be no higher than 2:1, that is, when the polymer is 1 part, the lubricant is at most 2 parts.

[0033] When an organic phase is added dropwise to a dispersed phase, the shear force of the impeller can be changed by adjusting the stirring speed, thus cutting the organic phase droplets into smaller droplets of different sizes and controlling the particle size. The faster the stirring speed, the smaller the particle size; conversely, the slower the stirring speed, the larger the particle size.

[0034] Specifically, the polymer can be one of PSF, PU, ​​PMMA, or PS.

[0035] The above-mentioned method for preparing single-shell PSF@lubricant microcapsules employs a solvent evaporation method. Dichloromethane, a common organic solvent, can better dissolve PSF and lubricant, and the three are thoroughly mixed to form a stable and homogeneous organic phase. The organic phase has low polarity in solution, while the gelatin solution has high polarity. By gradually mixing the two phases, the interfacial tension and affinity between the organic and dispersed phases are controlled, promoting the compatibility and stability of the organic and dispersed phases. Gradually adding the organic phase to the dispersed phase of the gelatin solution can make the organic phase gradually become insoluble or microencapsulated in the dispersed phase. The treated microcapsules can encapsulate the lubricant inside the polymer PSF shell, improving stability and controlled-release performance.

[0036] Specifically, the lubricant is a high-temperature resistant lubricant with a decomposition temperature > 350℃. More specifically, the lubricant is one or more of PAO2, PAO4, PAO6, PAO8, PAO10, PAO40, and ionic liquids. The decomposition temperature of the lubricant should be greater than 350℃.

[0037] (2) Pretreatment of single-shell PSF@lubricant microcapsules:

[0038] a. Place 10g of single-shell PSF@lubricant microcapsules in a degreasing solution composed of 40g-45g sodium hydroxide, 3g-5g degreasing agent, and 500ml deionized water, and perform surface degreasing at 60℃. This degreasing treatment removes unencapsulated lubricant from the single-shell PSF@lubricant microcapsules, ensuring that the microcapsules contain only the intended encapsulated lubricant, avoiding the presence of other impurities or unreacted substances, and improving the purity of the single-shell PSF@lubricant microcapsules.

[0039] b. After cleaning, the single-shell PSF@lubricant microcapsules are added to a mixed solution consisting of 350ml-370ml sulfuric acid (analytical grade), 10g-13g potassium dichromate, and 500ml deionized water, and roughened at 70℃-75℃ for 30min. This surface roughening treatment of the single-shell PSF@lubricant microcapsules (wall material and shell material) utilizes the strong oxidizing properties of sulfuric acid and potassium dichromate to form tiny pores or textures on the surface of the microcapsules, altering the surface morphology, providing more acidic binding sites, and increasing the contact area. The roughened surface treatment increases the surface roughness of the single-shell PSF@lubricant microcapsules, thus increasing their surface adhesion and improving the adhesion and compatibility of subsequent composite coatings with the microcapsules.

[0040] c. Add the pretreated single-shell PSF@lubricant microcapsules to a sensitization solution consisting of 6-8g stannous chloride, 0.03g-0.05g palladium chloride, 10ml-12ml hydrochloric acid (analytical grade), and 200ml deionized water. Sensitize with magnetic stirring for 10 minutes in a water bath at 30℃-35℃, then wash with deionized water. Add the sensitized single-shell PSF@lubricant microcapsules to an activation solution consisting of 0.03g-0.05g palladium chloride, 2ml-4ml hydrochloric acid (analytical grade), and 200ml deionized water. Activate with magnetic stirring for 10 minutes at 30℃-35℃, then wash with deionized water to remove free Pd. + The roughened single-shell PSF@lubricant microcapsules are immersed in a solution containing a sensitizer (stannous chloride), causing a reducing substance to adsorb onto the surface of the microcapsules. During activation treatment with an activator (palladium chloride), the reducing substance reduces the activator to a metallic state, that is, the activator is reduced to form catalytic crystal nuclei, which remain on the surface of the single-shell PSF@lubricant microcapsules. This allows subsequent electroless plating to be performed on the surface of the single-shell PSF@lubricant microcapsules.

[0041] (3) Forming a second shell layer consisting of a metal-friction-reducing agent composite coating on the surface of the single-shell PSF@lubricant microcapsules: The pretreated single-shell PSF@lubricant microcapsules were chemically plated in a plating solution at 50℃~85℃ for 30 minutes. The plating solution was one of Ni-P-PTFE plating solution, Cu-PTFE plating solution, Ni-P-MoS2 plating solution, Cu-MoS2 plating solution, Ni-P-Go plating solution, and Cu-Go plating solution. To maintain the stability of the plating solution, sodium hydroxide was added to keep the pH value of the plating solution at 4.5~5.5. After chemical plating, the microcapsules were washed and dried to obtain the coating-PSF@lubricant microcapsules. Chemical plating at the above temperature can promote the reaction, rapidly reduce the metal ions in the plating solution, and form a strong bond with the surface of the single-shell PSF@lubricant microcapsules, thus promoting the rapid formation of the coating. This dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule is formed by encapsulating a lubricant core material in a single-shell polymer microcapsule, and a second shell (metal-friction reducer composite coating) is formed on the surface of the single-shell polymer microcapsule through chemical composite plating. This enables the prepared dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule to achieve high temperature resistance, organic solvent resistance, and impart lubrication properties to the shell and core materials.

[0042] This invention also provides a dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule, prepared by the same method. The dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule comprises a polymer shell, a lubricant core encapsulated within the polymer shell, and a second shell layer composed of a metal-friction-reducing agent composite coating on the surface of the polymer shell. In this dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule, the polymer serves as the first shell layer, and the lubricant serves as the core material encapsulated by the polymer. A composite coating is applied to the surface of the polymer shell microcapsule through chemical composite plating. This composite coating serves as the second shell layer, and it forms a high-temperature resistant and organic solvent resistant protective layer on the surface of the PSF@lubricant microcapsule, providing friction reduction and wear resistance, thus improving the lubrication performance, temperature resistance, and organic solvent resistance of the dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule. Specifically, the thermogravimetric temperature of the dual-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule is >350℃, meaning its operating temperature can reach 350℃. Traditional polymer-shell microcapsules almost always melt and rupture at operating temperatures of 200°C, leading to microcapsule failure. By limiting the decomposition temperature of the liquid lubricant to above 350°C and forming a metal protective layer on the surface of the single-shell polymer microcapsule through chemical composite plating, the rupture temperature of the wall material of the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsule is guaranteed to be above 350°C. This ensures that the prepared double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsule does not fail at high temperatures. Compared with traditional polymer-shell microcapsules, the rupture temperature of the wall material of the prepared double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsule is much higher than the decomposition temperature of the core material.

[0043] To further illustrate the double-shell high-temperature resistant solid-liquid synergistic lubricating microcapsule and its preparation method provided by the present invention, the following embodiments are provided.

[0044] Example 1: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0045] (1) Preparation of PSF@PAO40 microcapsules: 3g of PSF and 3g of PAO40 were dissolved in 60ml of dichloromethane to prepare the organic phase; 4.5g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 35℃; the organic phase was added to 300ml of the dispersed phase by mechanical stirring at 800rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO40 microcapsules were obtained through centrifugation, washing, drying, and other processes.

[0046] (2) Pretreatment of PSF@PAO40 microcapsules:

[0047] a. Place 10g of PSF@PAO40 microcapsules in a degreasing solution consisting of 40g of sodium hydroxide, 4g of degreasing agent and 500ml of deionized water, and perform surface degreasing at 60℃.

[0048] b. Add the cleaned PSF@PAO40 microcapsules to a mixed solution consisting of 360ml concentrated sulfuric acid, 10g potassium dichromate and 500ml deionized water, and roughen them at 75℃ for 30min.

[0049] c. Add the pretreated PSF@PAO40 microcapsules to a mixed solution consisting of 8g stannous chloride, 10ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 35℃ for 10min and wash with deionized water. Then add the PSF@PAO40 microcapsules to a mixed solution consisting of 0.05g palladium chloride, 4ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 35℃ for 10min and wash with deionized water.

[0050] (3) Forming a Ni-P-PTFE composite coating on the surface of PSF@PAO40 microcapsules: The pretreated PSF@PAO40 microcapsules were placed in a plating solution at 80°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. Chemical plating was performed for 30 minutes. The Ni-P-PTFE plating solution consisted of 200 mL of deionized water, 10 g / L trisodium citrate, 20 g / L sodium acetate, 30 g / L lactic acid, 30 g / L nickel sulfate, 30 g / L sodium hypophosphite, and 2 g / L polytetrafluoroethylene solution.

[0051] Example 2: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0052] (1) Preparation of PSF@PAO2 microcapsules: 4g of PSF and 4g of PAO2 were dissolved in 65ml of dichloromethane to prepare the organic phase; 3g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 30℃; the organic phase was added to 300ml of the dispersed phase by mechanical stirring at 500rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO2 microcapsules were obtained through centrifugation, washing, drying and other processes.

[0053] (2) Pretreatment of PSF@PAO2 microcapsules:

[0054] a. Place 10g of PSF@PAO2 microcapsules in a degreasing solution consisting of 42g of sodium hydroxide, 3g of degreasing agent and 500ml of deionized water, and perform surface degreasing at 60℃.

[0055] b. Add the cleaned PSF@PAO2 microcapsules to a mixed solution consisting of 350ml concentrated sulfuric acid, 12g potassium dichromate and 500ml deionized water, and roughen them at 73℃ for 30min.

[0056] c. Add the pretreated PSF@PAO2 microcapsules to a mixed solution consisting of 6g stannous chloride, 10ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 32℃ for 10min and wash with deionized water. Then add the PSF@PAO2 microcapsules to a mixed solution consisting of 0.03g palladium chloride, 2ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 32℃ for 10min and wash with deionized water.

[0057] (3) Forming a Cu-PTFE composite coating on the surface of PSF@PAO2 microcapsules: The pretreated PSF@PAO2 microcapsules were placed in a plating solution at 50°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. 10 ml of formaldehyde reducing agent was slowly added dropwise to the plating solution, and then chemical plating was performed for 30 min. The Cu-PTFE plating solution consisted of 200 mL of deionized water, 12 g / L copper sulfate pentahydrate, 40 g / L sodium potassium tartrate, 5 g disodium ethylenediaminetetraacetate, and 2 g / L PTFE emulsion.

[0058] Example 3: A method for preparing a double-shell, temperature-resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0059] (1) Preparation of PSF@PAO4 microcapsules: 5g of PSF and 4g of PAO4 were dissolved in 70ml of dichloromethane to prepare the organic phase; 6g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 30℃; the above-mentioned volume of organic phase was added to 300ml of dispersed phase by mechanical stirring at 1000rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO4 microcapsules were obtained through centrifugation, washing, drying and other processes.

[0060] (2) Pretreatment of PSF@PAO4 microcapsules:

[0061] a. Place 10g of PSF@PAO4 microcapsules in a degreasing solution consisting of 45g sodium hydroxide, 5g degreasing agent and 500ml deionized water, and perform surface degreasing at 60℃.

[0062] b. Add the cleaned PSF@PAO4 microcapsules to a mixed solution consisting of 370ml concentrated sulfuric acid, 13g potassium dichromate and 500ml deionized water, and roughen them at 70℃ for 30min.

[0063] c. Add the pretreated PSF@PAO4 microcapsules to a mixed solution consisting of 7g stannous chloride, 11ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 35℃ for 10min and wash with deionized water. Then add the PSF@PAO4 microcapsules to a mixed solution consisting of 0.04g palladium chloride, 3ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 35℃ for 10min and wash with deionized water.

[0064] (3) Formation of Ni-P-MoS2 composite coating on the surface of PSF@PAO4 microcapsules: The pretreated PSF@PAO4 microcapsules were placed in a plating solution at 82°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. Chemical plating was performed for 30 min. The Ni-P-MoS2 plating solution consisted of 200 mL of deionized water, 10 g / L trisodium citrate, 20 g / L sodium acetate, 30 g / L lactic acid, 30 g / L nickel sulfate, 30 g / L sodium hypophosphite, and 1 g / L MoS2.

[0065] Example 4: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0066] (1) Preparation of PSF@PAO6 microcapsules: 5g of PSF and 3g of PAO6 were dissolved in 80ml of dichloromethane to prepare the organic phase; 5g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 30℃; the organic phase was added to 300ml of the dispersed phase by mechanical stirring at 800rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO6 microcapsules were obtained through centrifugation, washing, and drying.

[0067] (2) Pretreatment of PSF@PAO6 microcapsules:

[0068] a. Place 10g of PSF@PAO6 microcapsules in a degreasing solution consisting of 40g sodium hydroxide, 3g degreasing agent and 500ml deionized water, and perform surface degreasing at 60℃.

[0069] b. Add the cleaned PSF@PAO6 microcapsules to a mixed solution consisting of 350ml concentrated sulfuric acid, 11g potassium dichromate and 500ml deionized water, and roughen them at 75℃ for 30min.

[0070] c. Add the pretreated PSF@PAO6 microcapsules to a mixed solution consisting of 7g stannous chloride, 12ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 30℃ for 10min and wash with deionized water. Then add the PSF@PAO6 microcapsules to a mixed solution consisting of 0.03g palladium chloride, 4ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 30℃ for 10min and wash with deionized water.

[0071] (3) Formation of Cu-MoS2 composite coating on the surface of PSF@PAO6 microcapsules: The pretreated PSF@PAO6 microcapsules were placed in a plating solution at 60°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. 10 ml of reducing agent formaldehyde was slowly added dropwise to the plating solution, and chemical plating was performed for 30 min. The Cu-MoS2 plating solution consisted of 200 mL of deionized water, 12 g / L copper sulfate pentahydrate, 40 g / L sodium potassium tartrate, 5 g disodium ethylenediaminetetraacetate, and 1 g / L MoS2.

[0072] Example 5: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0073] (1) Preparation of PSF@PAO8 microcapsules: 5g of PSF and 5g of PAO8 were dissolved in 80ml of dichloromethane to prepare the organic phase; 3g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 32℃; the organic phase was added to 300ml of the dispersed phase by mechanical stirring at 600rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO8 microcapsules were obtained through centrifugation, washing, drying, and other processes.

[0074] (2) Pretreatment of PSF@PAO8 microcapsules:

[0075] a. Place 10g of PSF@PAO8 microcapsules in a degreasing solution consisting of 42g of sodium hydroxide, 4g of degreasing agent and 500ml of deionized water, and perform surface degreasing at 60℃.

[0076] b. Add the cleaned PSF@PAO8 microcapsules to a mixed solution consisting of 360ml concentrated sulfuric acid, 13g potassium dichromate and 500ml deionized water, and roughen them at 73℃ for 30min.

[0077] c. Add the pretreated PSF@PAO8 microcapsules to a mixed solution consisting of 6g stannous chloride, 10ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 35℃ for 10min and wash with deionized water. Then add the PSF@PAO8 microcapsules to a mixed solution consisting of 0.05g palladium chloride, 4ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 35℃ for 10min and wash with deionized water.

[0078] (3) Forming a Ni-P-Go composite coating on the surface of PSF@PAO8 microcapsules: The pretreated PSF@PAO8 microcapsules were placed in a plating solution at 80°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. Chemical plating was performed for 30 minutes. The Ni-P-Go plating solution consisted of 200 mL of deionized water, 10 g / L trisodium citrate, 20 g / L sodium acetate, 30 g / L lactic acid, 30 g / L nickel sulfate, 30 g / L sodium hypophosphite, and 1 g / L Go.

[0079] Example 6: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0080] (1) Preparation of PSF@PAO10 microcapsules: 4g of PSF and 3g of PAO10 were dissolved in 60ml of dichloromethane to prepare the organic phase; 5g of gelatin was dissolved in 300ml of water to prepare the dispersed phase at 30℃; the organic phase was added to 300ml of the dispersed phase by mechanical stirring at 700rpm. After the addition was complete, the solution temperature was increased and stirring continued until the dichloromethane was completely evaporated. Finally, PSF@PAO10 microcapsules were obtained through centrifugation, washing, drying, and other processes.

[0081] (2) Pretreatment of PSF@PAO10 microcapsules:

[0082] a. Place 10g of PSF@PAO10 microcapsules in a degreasing solution consisting of 45g sodium hydroxide, 3g degreasing agent and 500ml deionized water, and perform surface degreasing at 60℃.

[0083] b. Add the cleaned PSF@PAO10 microcapsules to a mixed solution consisting of 370ml concentrated sulfuric acid, 10g potassium dichromate and 500ml deionized water, and roughen them at 75℃ for 30min.

[0084] c. Add the pretreated PSF@PAO10 microcapsules to a mixed solution consisting of 6g stannous chloride, 10ml concentrated hydrochloric acid, and 200ml deionized water. Sensitize at 30℃ for 10min and wash with deionized water. Then add the PSF@PAO10 microcapsules to a mixed solution consisting of 0.04g palladium chloride, 4ml concentrated hydrochloric acid, and 200ml deionized water. Activate at 30℃ for 10min and wash with deionized water.

[0085] (3) Forming a Cu-Go composite coating on the surface of PSF@PAO10 microcapsules: The pretreated PSF@PAO10 microcapsules were placed in a plating solution at 70°C, sodium hydroxide was added dropwise, and the pH value was controlled within the range of 4.5-5.5. 10 ml of formaldehyde reducing agent was slowly added dropwise to the plating solution, and then chemical plating was performed for 30 min. The Cu-Go plating solution consisted of 200 mL of deionized water, 12 g / L copper sulfate pentahydrate, 40 g / L sodium potassium tartrate, 5 g disodium ethylenediaminetetraacetate, and 1 g / L Go.

[0086] Example 7: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0087] (1) Preparation of PU@ionic liquid microcapsules.

[0088] (2) The pretreatment and chemical composite plating process of PU@ ionic liquid microcapsules are the same as in Example 1.

[0089] Example 8: A method for preparing a double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0090] (1) Preparation of PS@PAO40 microcapsules.

[0091] (2) The pretreatment and chemical composite plating process of PS@PAO40 microcapsules are the same as in Example 1.

[0092] Example 9: A method for preparing a double-shell, temperature-resistant solid-liquid synergistic lubricating microcapsule, comprising the following steps:

[0093] (1) Preparation of PMMA@PAO40 microcapsules.

[0094] (2) The pretreatment and chemical composite plating process of PMMA@PAO40 microcapsules are the same as in Example 1.

[0095] Comparative Example 1: PSF@PAO6 microcapsules. The preparation method of Comparative Example 1 is the same as step (1) in the preparation method of Example 4. Comparative Example 1 does not involve the pretreatment of PSF@PAO6 microcapsules and chemical composite plating.

[0096] See Figure 1SEM morphology analysis was performed on the samples from Example 1 and Comparative Example 1. From... Figure 1 As can be seen, the surface of Comparative Example 1 is smooth, while the surface of Example 1 after chemical composite plating is covered with a rough composite plating layer.

[0097] See Figure 2 Surface EDS chemical composition analysis was performed on the sample of Example 1. It can be seen that F, Ni and P elements are all distributed on the surface of the prepared microcapsules, indicating that the chemical composite plating was successful.

[0098] See Figure 3 The thermal properties of each component in Example 1 were analyzed. The thermogravimetric analysis showed that Example 1 has excellent high temperature resistance, and the decomposition temperature of each component was greater than 350°C.

[0099] See Figure 4 After sintering Examples 1-6 and Comparative Example 1 at 350°C for 30 minutes, from... Figure 4 As can be seen from the examples, the double-shell high-temperature resistant solid-liquid lubricating microcapsules prepared in Examples 1-6 are still in powder form, while Comparative Example 1 is in a clump state. Due to the influence of high temperature, it melts and cracks, causing the PAO6 encapsulated in PSF to leak out and making it unusable.

[0100] Lubrication performance test

[0101] The lubrication effect was verified by blending and hot-pressing the microcapsules prepared in Examples 1-9 with nylon powder (PA powder). The mass percentage of the microcapsules was 10%, and the sintering temperature for the samples corresponding to Examples 1-9 was 230℃, the pressure was 4MPa, and the time was 30min.

[0102] Application Comparative Example 2: Pure PA

[0103] Comparative Example 3: Ni-P-PTFE-PSF hollow shells were blended with PA and sintered at a temperature of 230℃, a pressure of 4MPa, and a time of 30min.

[0104] The preparation method of the Ni-P-PTFE-PSF shell in Comparative Example 3 is as follows: the shell material PSF is roughened, sensitized, activated and chemically plated. The preparation method of the Ni-P-PTFE-PSF shell is basically the same as that in Example 1. The difference from Example 1 is that the PSF in Comparative Example 3 does not involve PAO40 as the core material.

[0105] Comparative Example 4: Ni-P-PSF@PAO40 microcapsules were blended with PA and sintered at a temperature of 230℃, a pressure of 4MPa, and a time of 30min.

[0106] The preparation method of Ni-P-PSF@PAO40 microcapsules in Comparative Example 4 is as follows: (1) Preparation of PSF@PAO40 microcapsules: The scheme is the same as in Example 1. (2) Pretreatment of PSF@PAO40 microcapsules: Compared with Example 1, no degreasing and roughening treatment was performed. (3) The PSF@PAO40 microcapsules after the above treatment were placed in a plating solution at 80°C, sodium hydroxide was added dropwise, the pH value was controlled within the range of 4.5-5.5, and chemical plating was performed for 30 minutes. The Ni-P plating solution consists of 200 mL of deionized water, 10 g / L trisodium citrate, 20 g / L sodium acetate, 30 g / L lactic acid, 30 g / L nickel sulfate, and 30 g / L sodium hypophosphite.

[0107] Tribological performance testing: The test was conducted using a UMT ball-and-disc testing machine. The test conditions were: pressure of 10N, frequency of 3Hz, and time of 2h.

[0108] The results are shown in Table 1. It can be seen that, compared to the pure PA material in Comparative Example 2, although Comparative Example 3 only contains a composite coating shell and no liquid lubricant, its friction coefficient and wear rate are significantly lower than those of the pure PA material in Comparative Example 2, indicating that the composite coating shell has a solid lubrication effect. The microcapsules prepared in Examples 1-9 all achieved low friction and wear in PA-based composite materials, and the friction coefficient and wear rate were significantly lower than those in Comparative Examples 2 and 3. This indicates that during friction, the microcapsule rupture releases the lubricant inside the shell, and the shell's synergistic effect achieves solid-liquid synergistic lubrication. The PSF@PAO40 microcapsules in Comparative Example 4 were not roughened, resulting in a relatively smooth surface and insufficient surface adhesion. This has a certain impact on the formation of the metal coating and reduces its density and integrity, leading to cracking in uncoated areas and thus reducing the high-temperature resistance of the Ni-P-PSF@PAO40 microcapsules. Furthermore, as can be seen from Table 1 below, the plating solution in Comparative Example 4, due to the absence of polytetrafluoroethylene solid lubricant, resulted in a metal coating that, while improving the temperature resistance of PSF@PAO40 microcapsules to some extent, did not exhibit significant friction-reducing and wear-resistant effects. The coefficient of friction and wear rate were still inferior to those of the microcapsules prepared in Examples 1-9. In other words, Comparative Example 4 could not form the temperature-resistant and lubricating composite coating of the present invention and did not have the effect of solid-liquid synergistic lubrication.

[0109] Table 1. Tribological test data for each sample

[0110]

[0111]

[0112] In summary, this invention uses a polymer shell as the basic material to prepare single-shell polymer microcapsules. The single-shell polymer microcapsules undergo degreasing, roughening, sensitization, and activation treatments to achieve a rough surface. A second shell layer, a composite coating, is then applied to the surface of the single-shell polymer microcapsules through chemical plating. This results in double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsules that possess both high-temperature resistance and lubrication properties in both the shell and core. This method ensures that the wall material fracture temperature of the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsules is significantly higher than the decomposition temperature of the core material, meeting the molding requirements of most polymers. The double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsules prepared by this method exhibit excellent density, ensuring that the single-shell polymer microcapsules are not damaged in polar / non-polar organic solvents. Furthermore, the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsules prepared by this method enable polymer materials to achieve excellent tribological properties under high speed, heavy load, and high temperature conditions, exhibiting excellent lubrication and friction-reducing effects.

[0113] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A method for preparing a double-shell, temperature-resistant, solid-liquid synergistic lubricating microcapsule, characterized in that, Includes the following steps: S1. Preparation of single-shell polymer microcapsules: Single-shell polymer microcapsules are prepared by encapsulating a lubricant with a polymer; the polymer is PSF; the lubricant is PAO10; S2. Pretreatment of single-shell polymer microcapsules: The single-shell polymer microcapsules are placed in an oil-removing solution for surface degreasing; the surface of the degreased single-shell polymer microcapsules is roughened; the roughened single-shell polymer microcapsules are then subjected to sensitization and activation treatments in sequence. S3. Forming a second shell layer on the surface of the single-shell polymer microcapsule, consisting of a metal-friction-reducing agent composite coating: The pretreated single-shell polymer microcapsule is placed in a plating solution for chemical plating, wherein the plating solution is a Cu-GO plating solution. After chemical plating, the microcapsule is washed and dried to obtain a double-shell heat-resistant solid-liquid synergistic lubricating microcapsule.

2. The method for preparing the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule according to claim 1, characterized in that, In step S2, 10 g of the single-shell polymer microcapsules are added to an oil removal solution consisting of 40 g to 45 g of sodium hydroxide, 3 g to 5 g of degreasing agent and 500 ml of deionized water, and the solution is degreased at 60 °C.

3. The method for preparing the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule according to claim 1, characterized in that, In the roughening process of step S2, the degreased single-shell polymer microcapsules are added to a mixed solution consisting of 350 ml to 370 ml of concentrated sulfuric acid, 10 g to 13 g of potassium dichromate and 500 ml of deionized water, and roughened at 70 ℃ to 75 ℃ for 30 min.

4. The method for preparing the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule according to claim 1, characterized in that, In step S2, the sensitization and activation treatments are as follows: the sensitization treatment involves adding the pretreated single-shell polymer microcapsules to a sensitization solution composed of 6 g–8 g stannous chloride, 10 ml–12 ml concentrated hydrochloric acid, and 200 ml deionized water, sensitizing at 30 °C–35 °C for 10 min, and then washing with deionized water; the activation treatment involves adding the sensitized single-shell polymer microcapsules to an activation solution composed of 0.03 g–0.05 g palladium chloride, 2 ml–4 ml concentrated hydrochloric acid, and 200 ml deionized water, activating at 30 °C–35 °C for 10 min, and then washing with deionized water.

5. The method for preparing the double-shell, high-temperature resistant solid-liquid synergistic lubricating microcapsule according to claim 1, characterized in that, In step S3, the pretreated single-shell polymer microcapsules are placed in the plating solution at 50 ℃~85 ℃ for chemical plating for 30 min.

6. A double-shell, temperature-resistant, solid-liquid synergistic lubricating microcapsule, characterized in that, The microcapsule is prepared by the method of preparing the double-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule according to any one of claims 1-5. The double-shell high-temperature resistant solid-liquid synergistic lubrication microcapsule includes a polymer shell material, a lubricant core material wrapped inside the polymer shell material, and a second shell layer composed of a metal-friction-reducing agent composite coating on the surface of the polymer shell material.

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