Super-lubricity microcapsule, composite material thereof and preparation methods of super-lubricity microcapsule and composite material

Abstract

The invention discloses a super-lubricity microcapsule, a composite material thereof and preparation methods of the super-lubricity microcapsule and the composite material. The super-smooth microcapsule comprises a core material and a wall material coating the core material, the core material comprises a component A and a component B; the component A comprises oxymolybdenum dialkyl dithiophosphate, molybdenum dialkyl dithiocarbamate, a molybdenum amine complex, molybdenum naphthenate, molybdenum alkyl salicylate, nitrogen-containing oxymolybdenum dialkyl dithiophosphate, molybdenum bisphenol, molybdenum thiophosphate, molybdenum hydroximic acid, molybdenum fatty acid, organic molybdate, molybdenum schiff base, tripolymolybdenum salt, ethyl thiotungstate and propyl thiotungstate; one or more of butyl thiotungstate and butyl thiotungstate; and the component B is ionic liquid or lubricating oil. The super-lubricity microcapsule composite material is prepared from a super-lubricity microcapsule and a base material with a core-shell structure, wherein the base material comprises a solid lubricant core material and a polymer shell material coating the core material. The preparation method disclosed by the invention is simple, feasible and high in operability, can realize macroscopic super-lubricity in an atmospheric environment, and has a very high application value.

Description

Technical Field

[0001] The invention relates to a super-slip microcapsule and a composite material thereof and a preparation method thereof, belonging to the technical field of lubricating materials. Background Art

[0002] Microcapsule technology refers to a micro-packaging technology for storing solids, liquids, and gases by encapsulating trace substances in polymer films. In addition to having the advantages of both core materials and shell materials, microcapsule materials also exhibit special properties that are far different from simple blends or copolymers due to the synergistic effect between the core-shell structure components. Due to different characteristic components, morphologies, controllable particle sizes and synergistic effects between components, microcapsules are widely used in electronics, food, medicine, cosmetics, agriculture, biology and other fields, and their development prospects are very optimistic. In addition, microcapsules are widely used to adjust or enhance the lubrication properties of materials and play an important role in the field of tribology. Superlubricity refers to a lubrication state with extremely low friction resistance or even complete disappearance (friction coefficient below 0.01). It is the ultimate goal of the development of lubrication technology and can greatly reduce the energy dissipation of the friction interface, effectively extend the life of components and enhance their reliability. The lubricant in the microcapsule is wrapped by a solid shell and can be used as a lubrication reinforcing filler in polymer composites, thereby achieving real-time release of the lubricant in the microcapsule under the stimulation of interfacial stress during the friction process. Microcapsules have great potential in improving the service performance of key moving pairs in advanced equipment due to their advantage of automatic response without external oil supply. By introducing microcapsules, the lubrication performance of polymer composites can be significantly improved, and the coefficient of friction (COF) of the resin matrix can be reduced to ~0.02. Nevertheless, achieving superlubricity of microcapsule composites remains a challenge. One of the reasons is that it is difficult to incorporate microcapsules into low-friction matrices with high molding temperatures (>250°C), such as polytetrafluoroethylene (PTFE), due to oil evaporation and shell decomposition. Therefore, it is of great research value to explore new microcapsule composite systems to achieve superlubricity with a friction coefficient below 0.01. Summary of the invention

[0003] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a super-lubricating microcapsule and its composite material and their preparation method, that is, to realize the composite of microcapsule and low-friction polymer matrix, so as to achieve macroscopic super-lubricity in atmospheric environment.

[0004] In a first aspect, the present invention provides an ultra-slippery microcapsule, comprising a core material and a wall material covering the core material; The core material comprises component A and component B; The component A is one or more of dialkyl dithiophosphoryl molybdenum, dialkyl dithiocarbamate molybdenum, molybdenum amine complex, cyclopentane acid molybdenum, alkyl salicylate molybdenum, nitrogen-containing dialkyl dithiophosphoryl molybdenum, bisphenol molybdenum, thiophosphate molybdenum, hydroxamic acid molybdenum, fatty acid molybdenum, organic molybdate, Schiff base molybdenum, trimerized molybdenum salt, ethyl thiotungstate, propyl thiotungstate, butyl thiotungstate, and ammonium thiotungstate; The component B is an ionic liquid or a lubricating oil, wherein the ionic liquid includes one or more of 1-butyl-3-methylimidazole hexafluorophosphate, 1-octyl-3-methylimidazole hexafluorophosphate, 1-ethyl-3-methylimidazole hexafluorophosphate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-ethyl-3-methylimidazole tetrafluoroborate, 1-octyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt, and 1-octyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt; and the lubricating oil includes one or more of PAO base oil, linseed oil, alkyl silicone oil, phenyl silicone oil, chain oil, tung oil, mineral oil, ester base oil, liquid paraffin, perfluoropolyether, heavy alkylbenzene, and oleic acid.

[0005] In the above-mentioned super-slippery microcapsules, the mass of component A is 0.1 to 50 wt % of the total mass of the core material.

[0006] In the above-mentioned ultra-slippery microcapsules, the wall material includes one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene, urea-formaldehyde resin, and polymethyl methacrylate.

[0007] In the above-mentioned super-slippery microcapsules, the particle size of the super-slippery microcapsules is 100 nm to 1000 μm; The wall thickness of the super-slippery microcapsule is 10 nm to 100 μm.

[0008] In a second aspect, the present invention provides a method for preparing the ultra-slippery microcapsules described in any one of the above, comprising the following steps: 1) mixing the component A and the component B to obtain the core material; 2) mixing the core material and the wall material and dissolving the mixture in an organic solvent to obtain an oil phase; 3) adding the oil phase into the aqueous phase composed of a surfactant and water, heating and reacting to obtain the ultra-slippery microcapsules.

[0009] In the above-mentioned method for preparing ultra-slippery microcapsules, in step 2), the mass ratio of the core material to the wall material is 1:(0.067-15), preferably 1:(0.25-2); The organic solvent is dichloromethane, acetone, ethyl acetate, carbon tetrachloride or petroleum ether; In step 3), the oil phase is added to the water phase under stirring or ultrasonic conditions, the stirring rate of mechanical stirring is 200 to 2000 rpm, and the ultrasonic power is 50 to 1500 W; The surfactant is one or a mixture of polyvinyl alcohol, Triton X100, Tween 80, sodium dodecylbenzene sulfonate, ammonium dodecyl sulfate, hexadecyltrimethylammonium bromide, gelatin, gum arabic, and lignin; The concentration of the surfactant in the aqueous phase is 0.05 to 10 wt %; The heating temperature is from room temperature to 80° C., and the heating time is from 0.5 to 10 hours.

[0010] In a third aspect, the present invention provides an ultra-lubricant microcapsule composite material, which is made of the ultra-lubricant microcapsules described in any one of the above items and a matrix material with a core-shell structure, wherein the matrix material includes a solid lubricant core material and a polymer shell material coating the core material.

[0011] In the above-mentioned super-lubricant microcapsule composite material, the solid lubricant core material is one or more of polyimide, polytetrafluoroethylene, graphite, graphene, molybdenum disulfide, boron nitride, polyamide-imide, polyetherimide, tungsten disulfide, black phosphorus, polyetheretherketone, polyphenylene sulfide, graphite fluoride, silver, and solid paraffin; The polymer shell material is one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene, urea-formaldehyde resin, and polymethyl methacrylate; The particle size of the matrix material is 100 nm to 100 μm; The mass fraction of the solid lubricant core material in the base material with a core-shell structure is 5 to 95 wt %.

[0012] In the above-mentioned super-slippery microcapsule composite material, the mass of the super-slippery microcapsules accounts for 0.5 to 50 wt % of the total mass of the super-slippery microcapsule composite material.

[0013] In a fourth aspect, the present invention provides a method for preparing the super-slippery microcapsule composite material as described in any one of the above items, comprising the following steps: mixing the super-slippery microcapsules and the matrix material and then sintering them to obtain the super-slippery microcapsule composite material.

[0014] In the above-mentioned method for preparing the ultra-slippery microcapsule composite material, the method for preparing the matrix material comprises the following steps: 1) dispersing the solid lubricant core material in water to obtain a core material dispersion; 2) Adding the precursor of the polymer shell material and the initiator to the core material dispersion, heating under an inert atmosphere for reaction, and obtaining the matrix material.

[0015] In the above-mentioned method for preparing the super-slippery microcapsule composite material, the concentration of the solid core material dispersion is 1 to 50 vol%; The reaction is carried out under stirring or ultrasonic conditions, the stirring rate of the mechanical stirring is 200 to 2000 rpm, and the ultrasonic power is 50 to 1500 W; The heating temperature is 40-90° C. and the heating time is 4-12 hours.

[0016] In the above-mentioned method for preparing the ultra-slippery microcapsule composite material, in the sintering step, the pressure is 1-20 MPa and the sintering temperature is 80-300°C.

[0017] The present invention has the following beneficial effects: Compared with the prior art, the present invention is based on microcapsule technology and combines solid-liquid coupling lubrication design to prepare microcapsules and composite materials that can achieve ultra-low lubrication. The preparation method is simple and feasible, with strong operability. The synthesis of microcapsules and composite materials of different types, particle sizes and coverage can be achieved by controlling the reaction conditions, and macroscopic super-lubricity can be achieved in an atmospheric environment, which has high application value. The present invention improves the microcapsule composite material system, achieves macroscopic super-lubricity of microcapsule composite materials, and creates a new method for achieving macroscopic super-lubricity under mild environmental conditions, providing a new idea for further promoting the practical application of super-lubricity in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] When considered in conjunction with the accompanying drawings, the present invention can be more completely and better understood and many of the accompanying advantages can be easily known by referring to the detailed description below, but the drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention, as shown in the figure: Figure 1 is a SEM image of silicone oil / MoDTC@PS microcapsules in Example 1 of the present invention; Figure 2 is a SEM image of PTFE@PMMA matrix powder in Example 1 of the present invention; Figure 3 is a photo of a microcapsule composite material sample in Example 1 of the present invention; Figure 4 is a TEM image of PAO / MoDTC@PS microcapsules in Example 2 of the present invention; Figure 5 It is a friction coefficient curve of the microcapsule composite material in Example 2 of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0021] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0022] In the present invention, when it comes to numerical ranges, unless otherwise specified, the numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range.

[0023] In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges included therein. In addition, in the description of the invention, "multiple" means at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0024] As described in the background technology, superlubricity refers to a lubrication state in which the friction resistance is extremely low or even completely absent (the friction coefficient is below 0.01), which can greatly reduce the energy dissipation of the friction interface. However, the current friction coefficient of lubricating microcapsules can only reach a minimum of about 0.02. How to achieve the composite of microcapsules and low-friction polymer matrix to achieve macroscopic superlubricity in the atmospheric environment is still a technical problem that needs to be solved urgently.

[0025] In the first part, the present invention provides an ultra-slippery microcapsule, comprising a core material and a wall material coating the core material; the core material comprises component A and component B; component A is one or more of dialkyl dithiophosphate oxymolybdenum, dialkyl dithiocarbamate molybdenum (MoDTC), molybdenum amine complex, cyclopentane acid molybdenum, alkyl salicylic acid molybdenum, nitrogen-containing dialkyl dithiophosphate oxymolybdenum, bisphenol molybdenum, thiophosphate molybdenum, hydroxamic acid molybdenum, fatty acid molybdenum, organic molybdate, Schiff base molybdenum, trimerized molybdenum salt, ethyl thiotungstate, propyl thiotungstate, butyl thiotungstate, and ammonium thiotungstate; component B is an ionic liquid or a lubricating oil, and the ionic liquid comprises 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-octyl-3-methylimidazole hexafluorophosphate ([OMIM]PF6), 1-ethyl-3-methylimidazole hexafluorophosphate Salt ([EMIM]PF6), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4), 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM]BF4), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([BMIM][NTf2]), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([EMIM][NTf2]), 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([OMIM][NTf2]), the lubricating oil includes one or more of PAO base oil, linseed oil, alkyl silicone oil, phenyl silicone oil, chain oil, tung oil, mineral oil, ester base oil, liquid paraffin, perfluoropolyether, heavy alkylbenzene, and oleic acid. It is understood that PAO base oil refers to polyalphaolefin base oil, including but not limited to PAO 2, PAO 4, PAO 6, PAO 8, mPAO65, mPAO 100, mPAO 150 and other series of PAO base oils. It should be noted that although the present invention specification only provides some embodiments of the combination of component A and component B to prepare super-lubricating microcapsules, component A is used as a solid lubricant and component B is used as a liquid lubricant. The present invention utilizes the synergistic lubrication of solid lubricants and liquid lubricants to achieve super-lubricity, and the component A and the component B can be selected as needed. Based on the above technical scheme, the present invention prepares super-lubricating microcapsules by combining component A and component B as core materials, which can greatly reduce the friction coefficient and can achieve macroscopic super-lubricity under atmospheric conditions.

[0026] In some embodiments, the mass of component A is 0.1-50 wt % of the total mass of the core material, including but not limited to 33%. Component A and component B are more conducive to exerting synergistic effects within this range.

[0027] In some embodiments, the wall material includes one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene (PS), urea-formaldehyde resin, and polymethyl methacrylate.

[0028] In some embodiments, the particle size of the super-slippery microcapsules is 100 nm to 1000 μm; the wall thickness of the super-slippery microcapsules is 10 nm to 100 μm.

[0029] In the second part, the present invention provides a method for preparing the ultra-slippery microcapsules described in any one of the above, comprising the following steps: 1) mixing the component A and the component B to obtain the core material; 2) mixing the core material and the wall material and dissolving the mixture in an organic solvent to obtain an oil phase; 3) adding the oil phase into the aqueous phase composed of a surfactant and water, heating and reacting to obtain the ultra-slippery microcapsules.

[0030] In some embodiments, in step 1), the mixture of component A and component B can be specifically ultrasonicated at 100 W power for 10 min; in step 2), the mass ratio of the core material to the wall material is 1:(0.067-15), preferably 1:(0.25-2), including but not limited to 1:1.3; the organic solvent can be reasonably selected according to the solubility of the core material and the wall material, for example, the organic solvent is dichloromethane, acetone, ethyl acetate, carbon tetrachloride or petroleum ether.

[0031] In some embodiments, in step 3), the oil phase is added to the water phase under stirring or ultrasonic conditions, the stirring rate of mechanical stirring is 200 to 2000 rpm, and the ultrasonic power is 50 to 1500 W; when the mechanical stirring rate and the ultrasonic power are set in the above ranges, it is possible to ensure that the oil phase and the water phase are uniformly mixed for emulsification reaction, such as under mechanical stirring conditions at a speed of 600 rpm.

[0032] In some embodiments, the surfactant is one or a mixture of polyvinyl alcohol, Triton X100, Tween 80, sodium dodecylbenzene sulfonate, ammonium dodecyl sulfate, hexadecyltrimethylammonium bromide, gelatin, gum arabic, and lignin; the concentration of the surfactant in the aqueous phase is 0.05 to 10 wt %; when the mass proportion of the surfactant in the aqueous phase and the volume ratio of the aqueous phase to the oil phase are within the above ranges, a stable oil-in-water (O / W) emulsion can be obtained when it is mixed with the oil phase.

[0033] In some embodiments, the heating temperature is room temperature to 80°C, and the time is 0.5 to 10 hours; within this temperature range and time range, the formation of microcapsules is more favorable. The term "room temperature" refers to 15 to 30°C, preferably 20 to 25°C, such as 25°C. The heating holding time can specifically be 4 hours.

[0034] It is understood that the method further comprises the following post-processing steps: filtering the solution after the reaction is completed, and washing and drying the obtained solid sample in sequence. Optionally, the drying is natural drying at room temperature, oven drying or freeze drying.

[0035] In the third part, the present invention provides an ultra-lubricant microcapsule composite material, which is made of the ultra-lubricant microcapsules described in any one of the above items and a matrix material with a core-shell structure, wherein the matrix material includes a solid lubricant core material and a polymer shell material coating the core material.

[0036] In some embodiments, optionally, the solid lubricant core material is one or more of polyimide, polytetrafluoroethylene (PTFE), graphite, graphene, molybdenum disulfide, boron nitride, polyamide-imide, polyetherimide, tungsten disulfide, black phosphorus, polyetheretherketone, polyphenylene sulfide, fluorinated graphite, silver, and solid paraffin. Optionally, the polymer shell material is one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene, urea-formaldehyde resin, and polymethyl methacrylate.

[0037] In some embodiments, the particle size of the matrix material is 100 nm to 100 μm; and the mass fraction of the solid lubricant core material in the matrix material is 5 to 95 wt %.

[0038] In some embodiments, the mass of the super-slippery microcapsules accounts for 0.5-50 wt % of the total mass of the super-slippery microcapsule composite material, including but not limited to 50 wt % and 33 wt %.

[0039] In the fourth part, the present invention provides a method for preparing the super-slippery microcapsule composite material as described in any one of the above items, comprising the following steps: mixing the super-slippery microcapsules and the matrix material and sintering them to obtain the super-slippery microcapsule composite material.

[0040] In some embodiments, the method for preparing the base material comprises the following steps: 1) dispersing the solid lubricant core material in water to obtain a core material dispersion; 2) Adding the precursor of the polymer shell material and the initiator to the core material dispersion, heating under an inert atmosphere for reaction, and obtaining the matrix material.

[0041] Further, the concentration of the solid core material dispersion is 1 to 50 vol%; optionally, the reaction is carried out under stirring or ultrasonic conditions, the stirring rate of the mechanical stirring is 200 to 2000 rpm (such as 600 rpm, 800 rpm), and the ultrasonic power is 50 to 1500 W; the heating temperature is 40 to 90 ° C, the time is 4 to 12 hours, such as 6 hours at 70 ° C; the reaction temperature and time are adjusted according to the polymerization reaction of the precursor and initiator under an inert atmosphere. When the temperature is too low, no reaction occurs, and when the temperature is too high, the reactants are easily destroyed. The precursor of the polymer shell material can be reasonably selected according to the polymer shell material. For example, when the polymer shell material is polymethyl methacrylate, methyl methacrylate (MMA) is selected as the shell material and azobisisobutyronitrile is selected as the initiator. The proportion of each raw material can be adjusted within a reasonable range according to the particle size and performance requirements. In a specific embodiment of the present invention, the ratio of polymethyl methacrylate concentrated dispersion (PTFE content 60%), methyl methacrylate and azobisisobutyronitrile is 20 mL: 20 mL: 0.5 g or 20 mL: 10 mL: 0.5 g.

[0042] It is understood that the method further comprises the following post-processing steps: filtering the solution after the reaction is completed, and washing and drying the obtained solid sample in sequence, wherein the drying is natural drying at room temperature, oven drying or freeze drying.

[0043] In some embodiments, in the sintering step, the pressure is 1-20 MPa, and the sintering temperature is 80-300° C., such as hot pressing sintering at 10 MPa and 100° C. for 30 min.

[0044] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0045] The methods used in the following examples, unless otherwise specified, are all conventional methods, carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0046] Example 1: Preparation of silicone oil / MoDTC@PS microcapsules and composite materials (1) Preparation of silicone oil / MoDTC@PS microcapsules S1: 2 g silicone oil and 1 g MoDTC were mixed and ultrasonicated at 100 W for 10 min to obtain microcapsule core material. The core material was mixed with 4 g PS (molecular weight 50,000) and dissolved in 50 mL dichloromethane to obtain an oil phase.

[0047] S2: Take 0.5 g of polyvinyl alcohol (0588 low viscosity type) and add it into 200 mL of deionized water to completely dissolve it to obtain an aqueous phase.

[0048] S3: The aqueous phase was transferred to a three-necked flask, and the oil phase was added under mechanical stirring at 600 rpm and kept at room temperature for 4 hours.

[0049] S4: The solution after the reaction is filtered, and the obtained solid sample is washed and then dried to obtain silicone oil / MoDTC@PS microcapsules, such as Figure 1 As shown, the particle size is 100 nm to 1000 μm, and the wall thickness is 10 nm to 100 μm.

[0050] (2) Preparation of PTFE@PMMA matrix material S1: Take 20 mL of concentrated polytetrafluoroethylene dispersion (PTFE content 60%), add it to 1000 mL of deionized water and transfer it to a four-necked flask, and pass nitrogen to remove the air in the flask.

[0051] S2: Add 20 mL of methyl methacrylate dropwise into a four-necked flask, followed by 0.5 g of azobisisobutyronitrile.

[0052] S3: Set the mechanical stirring speed to 600 rpm and heat the mixture in a water bath at 70 °C for 6 hours.

[0053] S4: The solution after the reaction is filtered, and the obtained solid sample is washed and then dried to obtain a PTFE@PMMA matrix material, such as Figure 2 As shown, the particle size is 100 nm to 100 μm.

[0054] (3) Preparation of microcapsule composite materials S1: The silicone oil / MoDTC@PS microcapsules prepared in (1) and the PTFE@PMMA matrix material prepared in (2) were mechanically mixed in a mass ratio of 1:1 to obtain a mixed powder.

[0055] S2: The mixed powder was hot-pressed and sintered at 10 MPa and 100 °C for 30 min to obtain a microcapsule composite material block, such as Figure 3 shown.

[0056] (4) Tribological properties test of composite materials The tribological properties of the composite material were tested on UMT5 (point contact mode, pressure 15 MPa, rate 6 mm / s). The stable friction coefficient of the microcapsule composite material was 0.008, and it was able to enter a super-lubricating state.

[0057] Example 2: Preparation of silicone oil / MoDTC@PS microcapsules and composite materials (1) Preparation of PAO / MoDTC@PS microcapsules S1: Take 2g PAO (PAO4, daily chemical grade) and 1g MoDTC, mix them, and ultrasonicate them at 100 W power for 10 min to obtain microcapsule core material. Mix the core material with 4g PS (molecular weight 50000) and dissolve them in 50 mL dichloromethane to obtain the oil phase.

[0058] S2: Take 0.5 g of polyvinyl alcohol (0588 low viscosity type) and add it into 200 mL of deionized water to completely dissolve it to obtain an aqueous phase.

[0059] S3: The aqueous phase was transferred to a three-necked flask, and the oil phase was added under mechanical stirring at 600 rpm and kept at room temperature for 4 hours.

[0060] S4: The solution after the reaction is filtered, and the obtained solid sample is washed and then dried to obtain PAO / MoDTC@PS microcapsules, such as Figure 4 As shown, the particle size is 100 nm~1000 μm and the wall thickness is 10 nm~100 μm.

[0061] (2) Preparation of PTFE@PMMA matrix material S1: Take 20 mL of concentrated polytetrafluoroethylene dispersion (PTFE content 60%), add it to 1000 mL of deionized water and transfer it to a four-necked flask, and pass nitrogen to remove the air in the flask.

[0062] S2: 10 mL of methyl methacrylate was added dropwise to a four-necked flask, followed by 0.5 g of azobisisobutyronitrile.

[0063] S3: Set the mechanical stirring speed to 800 rpm and heat the mixture in a water bath at 70 °C for 6 hours.

[0064] S4: The solution after the reaction is filtered, and the obtained solid sample is washed and then dried to obtain a PTFE@PMMA matrix material.

[0065] (3) Preparation of microcapsule composite materials S1: The microcapsules prepared in (1) and the PTFE@PMMA matrix material prepared in (2) are mechanically mixed in a mass ratio of 1:2 to obtain a mixed powder.

[0066] S2: The mixed powder was hot-pressed and sintered at 10 MPa and 100 °C for 30 min to obtain a microcapsule composite material block.

[0067] (4) Tribological properties test of composite materials The tribological properties of the composite material were tested on UMT5 (point contact mode, pressure 15 MPa, speed 6 mm / s). The change of friction coefficient with time is shown in Figure 5 As shown in the results, it can be seen that the friction coefficient of the microcapsule composite material can enter the super-slip state (stable friction coefficient of 0.0062).

[0068] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, can implement the present invention in a wider range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principle of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departing from the disclosed scope in the application and the changes made with conventional techniques known in the art.

Claims

1. A super-slippery microcapsule, characterized in that: Comprising a core material and a wall material covering said core material; The core material comprises component A and component B; The component A is one or more of dialkyl dithiophosphoryl molybdenum, dialkyl dithiocarbamate molybdenum, molybdenum amine complex, cyclopentane acid molybdenum, alkyl salicylate molybdenum, nitrogen-containing dialkyl dithiophosphoryl molybdenum, bisphenol molybdenum, thiophosphate molybdenum, hydroxamic acid molybdenum, fatty acid molybdenum, organic molybdate, Schiff base molybdenum, trimerized molybdenum salt, ethyl thiotungstate, propyl thiotungstate, butyl thiotungstate, and ammonium thiotungstate; The component B is an ionic liquid or a lubricating oil, wherein the ionic liquid includes one or more of 1-butyl-3-methylimidazole hexafluorophosphate, 1-octyl-3-methylimidazole hexafluorophosphate, 1-ethyl-3-methylimidazole hexafluorophosphate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-ethyl-3-methylimidazole tetrafluoroborate, 1-octyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt, 1-ethyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt, and 1-octyl-3-methylimidazole bistrifluoromethanesulfonyl imide salt; and the lubricating oil includes one or more of PAO base oil, linseed oil, alkyl silicone oil, phenyl silicone oil, chain oil, tung oil, mineral oil, ester base oil, liquid paraffin, perfluoropolyether, heavy alkylbenzene, and oleic acid.

2. The ultra-slippery microcapsule according to claim 1, characterized in that: The mass of component A is 0.1 to 50 wt % of the total mass of the core material.

3. The ultra-slippery microcapsule according to any one of claims 1-2, characterized in that: The wall material includes one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene, urea-formaldehyde resin, and polymethyl methacrylate.

4. The ultra-slippery microcapsule according to any one of claims 1 to 3, characterized in that: The particle size of the super-slippery microcapsules is 100 nm to 1000 μm; The wall thickness of the super-slippery microcapsule is 10 nm to 100 μm.

5. The method for preparing the ultra-slippery microcapsules according to any one of claims 1 to 4, characterized in that: The steps include: 1) mixing the component A and the component B to obtain the core material; 2) mixing the core material and the wall material and dissolving the mixture in an organic solvent to obtain an oil phase; 3) adding the oil phase into the aqueous phase composed of a surfactant and water, heating and reacting to obtain the ultra-slippery microcapsules.

6. The method for preparing super-slippery microcapsules according to claim 5, characterized in that: In step 2), the mass ratio of the core material to the wall material is 1:(0.067-15), preferably 1:(0.25-2); The organic solvent is dichloromethane, acetone, ethyl acetate, carbon tetrachloride or petroleum ether; In step 3), the oil phase is added to the water phase under stirring or ultrasonic conditions, the stirring rate of mechanical stirring is 200 to 2000 rpm, and the ultrasonic power is 50 to 1500 W; The surfactant is one or a mixture of polyvinyl alcohol, Triton X100, Tween 80, sodium dodecylbenzene sulfonate, ammonium dodecyl sulfate, hexadecyltrimethylammonium bromide, gelatin, gum arabic, and lignin; The concentration of the surfactant in the aqueous phase is 0.05 to 10 wt %; The heating temperature is from room temperature to 80° C., and the heating time is from 0.5 to 10 hours.

7. A super-slippery microcapsule composite material, characterized in that: The super-lubricating microcapsule is made of the super-lubricating microcapsule according to any one of claims 1 to 4 and a matrix material with a core-shell structure, wherein the matrix material comprises a solid lubricant core material and a polymer shell material coating the core material.

8. The ultra-slippery microcapsule composite material according to claim 7, characterized in that: The solid lubricant core material is one or more of polyimide, polytetrafluoroethylene, graphite, graphene, molybdenum disulfide, boron nitride, polyamide-imide, polyetherimide, tungsten disulfide, black phosphorus, polyetheretherketone, polyphenylene sulfide, fluorinated graphite, silver, and solid paraffin; The polymer shell material is one or more of polyimide, polysulfone, polyamide-imide, polyetherimide, polystyrene, urea-formaldehyde resin, and polymethyl methacrylate; The particle size of the matrix material is 100 nm to 100 μm; The mass fraction of the solid lubricant core material in the base material with a core-shell structure is 5 to 95 wt %.

9. The ultra-slippery microcapsule composite material according to any one of claims 7-8, characterized in that: The mass of the super-slippery microcapsules accounts for 0.5 to 50 wt % of the total mass of the super-slippery microcapsule composite material.

10. The method for preparing the super-smooth microcapsule composite material according to any one of claims 7 to 9, comprising the following steps: mixing the super-smooth microcapsules and the matrix material and then sintering them to obtain the super-smooth microcapsule composite material.

11. The method for preparing the super-slippery microcapsule composite material according to claim 10, characterized in that: The preparation method of the matrix material comprises the following steps: 1) dispersing the solid lubricant core material in water to obtain a core material dispersion; 2) Adding the precursor of the polymer shell material and the initiator to the core material dispersion, heating under an inert atmosphere for reaction, and obtaining the matrix material.

12. The method for preparing the super-slippery microcapsule composite material according to claim 11, characterized in that: The concentration of the solid core material dispersion is 1 to 50 vol%; The reaction is carried out under stirring or ultrasonic conditions, the stirring rate of the mechanical stirring is 200 to 2000 rpm, and the ultrasonic power is 50 to 1500 W; The heating temperature is 40-90° C. and the heating time is 4-12 hours.

13. The method for preparing the super-slippery microcapsule composite material according to any one of claims 10 to 12, characterized in that: In the sintering step, the pressure is 1-20 MPa and the sintering temperature is 80-300°C.

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