Magnetic oil-containing microcapsules, self-lubricating epoxy composites, and methods of making and using the same

Abstract

This invention provides magnetic oil-containing microcapsules, self-lubricating epoxy composite materials, their preparation methods, and applications, belonging to the field of functional materials technology. The magnetic oil-containing microcapsules provided by this invention include a hybrid shell and lubricating oil encapsulated within the hybrid shell. The hybrid shell includes a polysulfone matrix and amphiphilic Fe3O4 nanoparticles embedded in the polysulfone matrix. The magnetic oil-containing microcapsules provided by this invention exhibit good temperature resistance and encapsulation properties, which is beneficial for fully utilizing their lubricating effect during use. Using the magnetic oil-containing microcapsules provided by this invention in an epoxy resin matrix can yield a self-lubricating epoxy composite material with uniformly distributed magnetic oil-containing microcapsules. Alternatively, the distribution and position of the magnetic oil-containing microcapsules can be controlled by a magnetic field to obtain a self-lubricating epoxy composite material with a gradient distribution of magnetic oil-containing microcapsules, thus expanding the application of magnetic oil-containing microcapsules in the field of tribology.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to magnetic oil-containing microcapsules, self-lubricating epoxy composite materials, their preparation methods, and applications. Background Technology

[0002] Friction consumes about one-third of the world's primary energy, and wear causes approximately 60% of equipment damage or malfunction. Using lubricating materials is the most effective means to reduce friction, lower wear, achieve energy conservation and consumption reduction, and ensure equipment operation. Self-lubricating materials are functional materials that provide continuous lubrication on their own without the need for external lubricants during operation. Microcapsules encapsulating lubricants, as a type of self-lubricating material, not only release liquid lubricant from the microcapsule to the interface when triggered by friction (load or temperature), but also overcome the shortcomings of external lubrication, improving the durability of the effective lubrication process.

[0003] The shell of microcapsules encapsulating lubricants has a significant impact on their performance. Organic shells have limited thermal stability, while inorganic shells have a looser structure and poor encapsulation properties, which greatly restricts the application of microcapsules encapsulating lubricants. Summary of the Invention

[0004] The purpose of this invention is to provide magnetic oil-containing microcapsules, self-lubricating epoxy composite materials, preparation methods, and applications. The magnetic oil-containing microcapsules provided by this invention have good temperature resistance and encapsulation properties, which helps to fully exert their lubricating effect during use.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] The present invention provides a magnetic oil-containing microcapsule, comprising a hybrid shell and a lubricating oil encapsulated within the hybrid shell, wherein the hybrid shell comprises a polysulfone matrix and amphiphilic Fe3O4 nanoparticles embedded in the polysulfone matrix.

[0007] Preferably, the magnetic oil-containing microcapsules have an average particle size of 30.53–86.12 μm.

[0008] Preferably, the oil content of the magnetic oil-containing microcapsules is 50.3% to 55.6%.

[0009] This invention provides a method for preparing the magnetic oil-containing microcapsules described above, comprising the following steps:

[0010] Amphiphilic Fe3O4 nanoparticles, sodium chloride, and water were mixed to obtain an aqueous phase.

[0011] Polysulfone, lubricating oil, and organic solvent are mixed to obtain an organic phase;

[0012] The organic phase was added to the aqueous phase and subjected to emulsification and encapsulation processes to obtain magnetic oil-containing microcapsules.

[0013] Preferably, the amphiphilic Fe3O4 nanoparticles are obtained by grafting Fe3O4 nanoparticles with a silane coupling agent.

[0014] Preferably, the emulsification process is carried out at a rotation speed of 13,000 to 18,000 rpm for 3 to 7 minutes; the encapsulation process is carried out at a rotation speed of 500 to 1,000 rpm for 30 to 36°C for 3 to 6 hours.

[0015] This invention provides a self-lubricating epoxy composite material, comprising an epoxy resin matrix and magnetic oil-containing microcapsules uniformly or gradually distributed in the epoxy resin matrix; the magnetic oil-containing microcapsules are the magnetic oil-containing microcapsules described in the above technical solution or the magnetic oil-containing microcapsules prepared by the preparation method described in the above technical solution.

[0016] Preferably, the epoxy resin matrix is ​​formed from epoxy resin and a curing agent, and the mass of the magnetic oil-containing microcapsules is 5-20% of the total mass of the epoxy resin and the magnetic oil-containing microcapsules.

[0017] This invention provides a method for preparing the self-lubricating epoxy composite material described above, comprising the following steps:

[0018] Epoxy resin, curing agent and magnetic oil-containing microcapsules are mixed and pre-cured and cured sequentially under no magnetic field or magnetic field conditions to obtain self-lubricating epoxy composite material.

[0019] This invention provides the application of the self-lubricating epoxy composite material described in the above technical solution or the self-lubricating epoxy composite material prepared by the preparation method described in the above technical solution in the preparation of polymer bearings.

[0020] This invention provides a magnetic oil-containing microcapsule, comprising a hybrid shell and a lubricating oil encapsulated within the hybrid shell. The hybrid shell comprises a polysulfone matrix and amphiphilic Fe3O4 nanoparticles embedded within the polysulfone matrix. The magnetic oil-containing microcapsule provided by this invention uses amphiphilic Fe3O4 nanoparticles and a polysulfone matrix to form a hybrid shell, exhibiting good temperature resistance and encapsulation properties. Furthermore, the amphiphilic Fe3O4 nanoparticles on the hybrid shell can act as a solid lubricant, playing a certain load-bearing role during friction and achieving a synergistic lubrication effect with the lubricating oil. Using the magnetic oil-containing microcapsules provided by this invention in an epoxy resin matrix can yield a self-lubricating epoxy composite material with uniformly distributed magnetic oil-containing microcapsules. Alternatively, the distribution and position of the magnetic oil-containing microcapsules can be controlled by a magnetic field to obtain a self-lubricating epoxy composite material with a gradient distribution of magnetic oil-containing microcapsules. Compared with the self-lubricating epoxy composite material with uniformly distributed magnetic oil-containing microcapsules, the self-lubricating epoxy composite material with a gradient distribution of magnetic oil-containing microcapsules requires less material while maintaining comparable tribological properties. This minimizes the loss of mechanical properties caused by the addition of microcapsules, potentially enabling intelligent lubrication and further expanding the application of magnetic oil-containing microcapsules in the field of tribology (such as in the preparation of polymer bearings).

[0021] This invention provides a method for preparing the aforementioned magnetic oil-containing microcapsules, comprising the following steps: mixing amphiphilic Fe3O4 nanoparticles, sodium chloride, and water to obtain an aqueous phase; mixing polysulfone, lubricating oil, and an organic solvent to obtain an organic phase; and adding the organic phase to the aqueous phase for emulsification and encapsulation treatments to obtain magnetic oil-containing microcapsules. This invention uses a Pickering emulsion template method combined with a solvent evaporation method to prepare magnetic oil-containing microcapsules, which is relatively simple to operate. Attached Figure Description

[0022] Figure 1 The image shows the FT-IR spectra and water contact angle comparison of Fe3O4 nanoparticles before and after modification in Example 1.

[0023] Figure 2 This is a SEM image of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules in Example 1;

[0024] Figure 3 The particle size distribution and thermogravimetric curve of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules in Example 1 are shown.

[0025] Figure 4 Thermogravimetric curves of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules, PAO10 lubricating oil, and PSF in Example 1 are shown.

[0026] Figure 5 SEM images of the self-lubricating epoxy composites prepared in Examples 1 and 5;

[0027] Figure 6 The friction coefficient curves of the materials prepared for the examples and comparative examples are shown. Detailed Implementation

[0028] This invention provides a magnetic oil-containing microcapsule, comprising a hybrid shell and a lubricating oil encapsulated within the hybrid shell. The hybrid shell comprises a polysulfone matrix and amphiphilic Fe3O4 nanoparticles embedded in the polysulfone matrix. In this invention, the average particle size of the magnetic oil-containing microcapsule is preferably 30.53–86.12 μm, more preferably 30.53–40.65 μm; the oil content of the magnetic oil-containing microcapsule is preferably 50.3–55.6%, more preferably 50.3–53.2%.

[0029] This invention provides a method for preparing the magnetic oil-containing microcapsules described above, comprising the following steps:

[0030] Amphiphilic Fe3O4 nanoparticles, sodium chloride, and water were mixed to obtain an aqueous phase.

[0031] Polysulfone, lubricating oil, and organic solvent are mixed to obtain an organic phase;

[0032] The organic phase was added to the aqueous phase and subjected to emulsification and encapsulation processes to obtain magnetic oil-containing microcapsules.

[0033] Unless otherwise specified, all raw materials used in this invention are commercially available products well known to those skilled in the art.

[0034] This invention involves mixing amphiphilic Fe3O4 nanoparticles, sodium chloride, and water to obtain an aqueous phase. Preferably, the amphiphilic Fe3O4 nanoparticles are obtained by grafting Fe3O4 nanoparticles with a silane coupling agent. Specifically, Fe3O4 nanoparticles, a silane coupling agent, ethanol, and water are mixed and grafted to obtain the amphiphilic Fe3O4 nanoparticles. In this invention, the particle size of the Fe3O4 nanoparticles is preferably 10–50 nm, and the contact angle is preferably 15.8°–29.7°, more preferably 23.4°–29.7°. In this invention, the silane coupling agent is preferably triethoxy-1H,1H,2H,2H-tridecylfluoro-n-octylsilane. By grafting the silane coupling agent onto Fe3O4 nanoparticles, this invention can increase the contact angle of the Fe3O4 nanoparticles, making them amphiphilic (both hydrophilic and lipophilic), which is beneficial for meeting the requirements of subsequent Pickering emulsion preparation. In this invention, the contact angle of the amphiphilic Fe3O4 nanoparticles is preferably 91.3°–92.4°. In this invention, the mass ratio of the Fe3O4 nanoparticles to the silane coupling agent is preferably (8–12):(2–3), more preferably (9–10):2. In this invention, the ethanol is preferably anhydrous ethanol, and the water is preferably ultrapure water; the preferred ratio of Fe3O4 nanoparticles, ethanol, and water is (8-12) g:(100-140) mL:(20-60) mL, more preferably (9-10) g:(110-120) mL:(30-40) mL. In this invention, the grafting modification is preferably carried out under reflux conditions, the reflux temperature is preferably 50-80°C, more preferably 60-65°C; the grafting modification time is preferably 4-6 h, more preferably 4.5-5 h. After grafting modification, the resulting system is preferably washed with anhydrous ethanol, and the solid material is separated using a magnet. After drying, amphiphilic Fe3O4 nanoparticles are obtained; the drying temperature is preferably 70-90°C, more preferably 75-80°C; the drying time is preferably 10-15 h, more preferably 12 h.

[0035] After obtaining the amphiphilic Fe3O4 nanoparticles, the present invention mixes the amphiphilic Fe3O4 nanoparticles, sodium chloride, and water to obtain an aqueous phase. In the present invention, the water is preferably ultrapure water; the preferred ratio of the amphiphilic Fe3O4 nanoparticles, sodium chloride, and water is (0.4-0.8) g:(1-3) g:(100-200) mL, more preferably (0.5-0.6) g:(1-2) g:(100-110) mL; the addition of sodium chloride in the present invention helps to improve the stability of the emulsion.

[0036] This invention involves mixing polysulfone (PSF), lubricating oil, and an organic solvent to obtain an organic phase. In this invention, the lubricating oil is preferably a base lubricating oil, which preferably includes PAO4, PAO10, PAO20, or Pegasus No. 2 lubricating oil; the organic solvent preferably includes dichloromethane; the preferred ratio of polysulfone, lubricating oil, and organic solvent is (1–2) g:(1.5–3) g:(100–200) mL, more preferably (1–1.3) g:(1.5–2) g:(100–150) mL.

[0037] After obtaining the aqueous phase and the organic phase, the present invention adds the organic phase to the aqueous phase and performs emulsification and encapsulation treatments sequentially to obtain magnetic oil-containing microcapsules. In the present invention, the preferred mass ratio of polysulfone in the organic phase to amphiphilic Fe3O4 nanoparticles in the aqueous phase is (1-2):(0.4-0.8), more preferably (1-1.3):(0.5-0.6). In the present invention, the emulsification treatment is preferably performed at a rotation speed of 13000-18000 rpm, more preferably 14000-16000 rpm; the preferred emulsification treatment time is 3-7 min, more preferably 4-5 min. In the present invention, the encapsulation treatment is preferably performed at a rotation speed of 500-1000 rpm, more preferably 800-900 rpm; the preferred encapsulation treatment temperature is 30-36℃, more preferably 32-34℃; the preferred encapsulation treatment time is 3-6 h, more preferably 5-6 h. In this invention, during the emulsification process, amphiphilic Fe3O4 nanoparticles adsorb onto the oil-water interface, stabilizing the emulsion to obtain a Pickering emulsion. During the encapsulation process, dichloromethane gradually evaporates, precipitating polysulfone and lubricating oil. The polysulfone forms a film at the oil-water interface, encapsulating the lubricating oil. Simultaneously, the amphiphilic Fe3O4 nanoparticles at the oil-water interface are embedded in the polysulfone film, resulting in magnetic oil-containing hybrid shell microcapsules. After the encapsulation process, this invention preferably involves filtering, washing, and drying the resulting mixture to obtain magnetic oil-containing microcapsules.

[0038] This invention provides a self-lubricating epoxy composite material, comprising an epoxy resin matrix and magnetic oil-containing microcapsules uniformly or gradually distributed within the epoxy resin matrix; the magnetic oil-containing microcapsules are the magnetic oil-containing microcapsules described in the above-mentioned technical solution or magnetic oil-containing microcapsules prepared by the preparation method described in the above-mentioned technical solution. In this invention, the magnetic oil-containing microcapsules can be uniformly distributed within the epoxy resin matrix or gradually distributed within the epoxy resin matrix, preferably gradually distributed within the epoxy resin matrix. In this invention, the epoxy resin matrix is ​​preferably formed from epoxy resin and a curing agent; the epoxy resin preferably includes bisphenol A epoxy resin E51 or epoxy resin E44; the curing agent preferably includes curing agent mocha (MOCA), tetraethylenepentamine, triethylenetetramine, polyetheramine, or diethyltoluenediamine; the mass ratio of the epoxy resin to the curing agent is preferably (1-5):1, more preferably (3-4):1. In this invention, the mass of the magnetic oil-containing microcapsules is preferably 5-20% of the total mass of the epoxy resin and the magnetic oil-containing microcapsules, more preferably 10-15%.

[0039] This invention provides a method for preparing the self-lubricating epoxy composite material described above, comprising the following steps:

[0040] Epoxy resin, curing agent and magnetic oil-containing microcapsules are mixed and pre-cured and cured sequentially under no magnetic field or magnetic field conditions to obtain self-lubricating epoxy composite material.

[0041] In this invention, the pre-curing and curing are preferably carried out in a mold, preferably a PTFE mold. Specifically, the epoxy resin, curing agent, and magnetic oil-containing microcapsules are mixed and poured into the mold, followed by pre-curing and curing. In this invention, when preparing a self-lubricating epoxy composite material with uniformly distributed magnetic oil-containing microcapsules, the mixed raw materials placed in the mold are pre-cured and cured sequentially under no magnetic field conditions. The pre-curing temperature is preferably 60–100°C, more preferably 70–80°C; the pre-curing time is preferably 2–4 hours, more preferably 2–3 hours; the curing temperature is preferably 100–140°C, more preferably 110–120°C; and the curing time is preferably 6–10 hours, more preferably 7–8 hours. In this invention, when preparing a self-lubricating epoxy composite material with a gradient distribution of magnetic oil-containing microcapsules, the mold containing the mixed raw materials is placed in the presence of a magnetic field for 5 to 10 minutes, and then pre-cured and cured sequentially in the presence of a magnetic field. The magnetic induction intensity of the magnetic field is preferably 0.2 to 0.6 T, more preferably 0.3 to 0.4 T. The pre-curing and curing conditions are preferably the same as those described above, and will not be repeated here.

[0042] This invention provides the application of the self-lubricating epoxy composite material described in the above technical solution or the self-lubricating epoxy composite material prepared by the preparation method described in the above technical solution in the preparation of polymer bearings.

[0043] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0044] Example 1

[0045] (1) Preparation of amphiphilic Fe3O4 nanoparticles:

[0046] Weigh 10g of Fe3O4 nanoparticles (particle size 10-50nm), 2g of triethoxy-1H,1H,2H,2H-tetrafluoro-n-octylsilane, 120mL of anhydrous ethanol and 40mL of ultrapure water, mix them and put them into a three-necked flask with a mechanical stirrer. Heat and stir under reflux at 65℃ for 5h. Then wash with anhydrous ethanol several times and separate the solids with a magnet. Dry at 80℃ for 12h to obtain amphiphilic Fe3O4 nanoparticles.

[0047] (2) Preparation of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules:

[0048] 0.6 g of amphiphilic Fe3O4 nanoparticles and 1 g of sodium chloride were weighed and added to 100 mL of ultrapure water. The mixture was sonicated until the amphiphilic Fe3O4 nanoparticles were completely dispersed to obtain an aqueous phase. 1 g of polysulfone (PSF) and 1.5 g of PAO10 lubricating oil were weighed and added to 100 mL of dichloromethane. After complete dissolution, an organic phase was obtained. The organic phase was added to the aqueous phase and dispersed at 14000 rpm for 5 min. Then, the stirring speed was kept constant at 900 rpm and stirred at 34 °C for 6 h. The resulting mixture was filtered and washed multiple times, and then dried to obtain magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules.

[0049] (3) Preparation of self-lubricating epoxy composite materials with microcapsule gradient distribution:

[0050] Weigh 9g of bisphenol A epoxy resin E51, 3g of curing agent MOCA, and 1g of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules and mix them evenly. Pour the resulting mixture into a PTFE mold and place it in a strong magnetic field (magnetic induction intensity of 0.4T) for 5 minutes. Then, maintain the strong magnetic field and pre-cure at 80℃ for 2 hours. Next, cure at 120℃ for 8 hours to obtain a self-lubricating epoxy composite material with a gradient distribution of microcapsules, denoted as T-10%.

[0051] Figure 1 The images show the FT-IR spectra and water contact angles of Fe3O4 nanoparticles before and after modification. (a) shows the FT-IR spectra of Fe3O4 nanoparticles before and after modification; (b) shows the water contact angle of Fe3O4 nanoparticles before modification; and (c) shows the water contact angle of Fe3O4 nanoparticles after modification. Figure 1 It can be seen that the FT-IR spectrum at 1206 cm⁻¹ -1 and 1148cm -1 A new absorption peak appears, corresponding to the antisymmetric and symmetric stretching vibrations of -CF2-. The water contact angle of the modified Fe3O4 nanoparticles increases from 29.7° to 92.4°, indicating a change from hydrophilic to amphiphilic (both hydrophilic and lipophilic). All of the above demonstrates that triethoxy-1H,1H,2H,2H-tetrafluoro-n-octylsilane has been successfully grafted onto Fe3O4 nanoparticles, meeting the requirements for preparing Pickering emulsions.

[0052] Figure 2 The image shows a SEM image of a magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsule. The microcapsule is spherical with a dense and rough surface, indicating that the lubricating oil was successfully encapsulated and the Fe3O4 nanoparticles were also embedded in the wall of the microcapsule.

[0053] Figure 3 The images show the particle size distribution and thermogravimetric analysis (TGA) curves of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules. (a) shows the particle size distribution of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules, and (b) shows the TGA curves. Figure 3 It can be seen that the maximum particle size of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules is 89.36 μm, the minimum particle size is 15.86 μm, and the average particle size is 30.53 μm. The thermogravimetric curve shows that the oil content of the microcapsules is 50.3%, which indicates that the microcapsules prepared by the present invention have good encapsulation properties and are not easy to leak. Even after multiple filtrations and washings during the preparation process, they can still maintain a high oil content.

[0054] Figure 4Thermogravimetric curves of the magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules, PAO10 lubricating oil, and PSF were obtained. The results showed that the decomposition temperature of PAO10 lubricating oil increased by about 30℃ (the decomposition temperature of PAO10 lubricating oil is 278.9℃, and the decomposition temperature of PAO10 lubricating oil in the microcapsules is 308.6℃), and the decomposition rate slowed down, indicating that the microcapsules provided by the present invention have good heat resistance.

[0055] Example 2

[0056] Preparation of self-lubricating epoxy composite materials with uniformly distributed microcapsules:

[0057] Weigh 9.5g of bisphenol A epoxy resin E51, 3.2g of curing agent MOCA and 0.5g of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules prepared in Example 1 and mix them evenly. Pour the resulting mixture into a PTFE mold and pre-cure at 80°C for 2 hours, then cure at 120°C for 8 hours to obtain a self-lubricating epoxy composite material with uniformly distributed microcapsules, denoted as J-5%.

[0058] Example 3

[0059] Preparation of self-lubricating epoxy composite materials with uniformly distributed microcapsules:

[0060] Weigh 9g of bisphenol A epoxy resin E51, 3g of curing agent MOCA and 1g of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules prepared in Example 1 and mix them evenly. Pour the resulting mixture into a PTFE mold and pre-cure at 80°C for 2h, then cure at 120°C for 8h to obtain a self-lubricating epoxy composite material with uniformly distributed microcapsules, denoted as J-10%.

[0061] Example 4

[0062] Preparation of self-lubricating epoxy composite materials with uniformly distributed microcapsules:

[0063] Weigh 8.5g of bisphenol A epoxy resin E51, 2.8g of curing agent MOCA and 1.5g of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules prepared in Example 1 and mix them evenly. Pour the resulting mixture into a PTFE mold and pre-cur it at 80°C for 2 hours, and then cure it at 120°C for 8 hours to obtain a self-lubricating epoxy composite material with uniformly distributed microcapsules, denoted as J-15%.

[0064] Example 5

[0065] Preparation of self-lubricating epoxy composite materials with uniformly distributed microcapsules:

[0066] Weigh 8g of bisphenol A epoxy resin E51, 2.7g of curing agent MOCA and 2g of magnetic oil-containing Fe3O4 / PSF hybrid shell microcapsules prepared in Example 1 and mix them evenly. Pour the resulting mixture into a PTFE mold and pre-cur it at 80°C for 2 hours, and then cure it at 120°C for 8 hours to obtain a self-lubricating epoxy composite material with uniformly distributed microcapsules, denoted as J-20%.

[0067] Figure 5 SEM images of the self-lubricating epoxy composites prepared in Examples 1 and 5, by... Figure 5 It can be seen that the microcapsules in the self-lubricating epoxy composite material prepared in Example 5 are uniformly distributed, while in the process of preparing the self-lubricating epoxy composite material in Example 1, when the epoxy resin is cured, the microcapsules are adsorbed to one side under the action of a strong magnetic field, resulting in different concentrations of microcapsules on both sides of the self-lubricating epoxy composite material, that is, forming a gradient distribution state.

[0068] Comparative Example 1

[0069] Weigh 10g of bisphenol A epoxy resin E51 and 3.3g of curing agent MOCA and mix them evenly. Pour the resulting mixture into a PTFE mold and pre-cure at 80℃ for 2 hours, then cure at 120℃ for 8 hours to obtain pure epoxy resin material, denoted as EP.

[0070] The materials prepared in the examples and comparative examples were subjected to performance tests. Specifically, the coefficient of friction of the materials was characterized using a CSM friction machine under the following conditions: ball-disc-rotation mode, GCr15 steel ball with a diameter of 3 mm, load of 5 N, speed of 3 cm / s, and rotation radius of 5 cm.

[0071] Figure 6 The friction coefficient curves of the materials prepared in the examples and comparative examples are shown below. Figure 6 As can be seen, for self-lubricating epoxy composites with uniformly distributed microcapsules, the coefficient of friction gradually decreases with the addition of microcapsules, reaching a minimum of 0.08 when the microcapsule mass fraction is 20 wt.%. For self-lubricating epoxy composites with gradient microcapsule distribution, only 10 wt.% of microcapsules were added to achieve a coefficient of friction of 0.08, meaning that the amount of microcapsules added was significantly reduced while maintaining the same lubrication effect. This indicates that by ensuring the orderly distribution of microcapsules within the epoxy matrix, the desired performance can be achieved while minimizing the amount of microcapsules used, thus minimizing the loss of mechanical properties of the composite material due to the addition of microcapsules. This holds promise for achieving intelligent lubrication and further enhancing the application of microcapsules in the field of tribology.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A magnetic oil-containing microcapsule, comprising a hybrid shell and a lubricating oil encapsulated within the hybrid shell, wherein the hybrid shell comprises a polysulfone matrix and amphiphilic Fe3O4 nanoparticles embedded in the polysulfone matrix; the magnetic oil-containing microcapsule has an average particle size of 30.53~86.12 μm.

2. The magnetic oil-containing microcapsule according to claim 1, characterized in that, The oil content of the magnetic oil-containing microcapsules is 50.3-55.6%.

3. A method for preparing the magnetic oil-containing microcapsules according to claim 1 or 2, comprising the following steps: Amphiphilic Fe3O4 nanoparticles, sodium chloride, and water were mixed to obtain an aqueous phase. Polysulfone, lubricating oil, and organic solvent are mixed to obtain an organic phase; The organic phase was added to the aqueous phase and subjected to emulsification and encapsulation processes to obtain magnetic oil-containing microcapsules.

4. The preparation method according to claim 3, characterized in that, The amphiphilic Fe3O4 nanoparticles were obtained by grafting Fe3O4 nanoparticles with a silane coupling agent.

5. The preparation method according to claim 3, characterized in that, The emulsification process is carried out at a speed of 13,000 to 18,000 rpm for 3 to 7 minutes; the encapsulation process is carried out at a speed of 500 to 1,000 rpm for 30 to 36°C for 3 to 6 hours.

6. A self-lubricating epoxy composite material, comprising an epoxy resin matrix and magnetic oil-containing microcapsules uniformly or gradually distributed in the epoxy resin matrix; wherein the magnetic oil-containing microcapsules are the magnetic oil-containing microcapsules according to claim 1 or 2 or the magnetic oil-containing microcapsules prepared by the preparation method according to any one of claims 3 to 5.

7. The self-lubricating epoxy composite material according to claim 6, characterized in that, The epoxy resin matrix is ​​formed from epoxy resin and curing agent, and the mass of the magnetic oil-containing microcapsules is 5-20% of the total mass of epoxy resin and magnetic oil-containing microcapsules.

8. A method for preparing the self-lubricating epoxy composite material according to claim 6 or 7, comprising the following steps: Epoxy resin, curing agent and magnetic oil-containing microcapsules are mixed and pre-cured and cured sequentially under no magnetic field or magnetic field conditions to obtain self-lubricating epoxy composite material.

9. The application of the self-lubricating epoxy composite material according to claim 6 or 7 or the self-lubricating epoxy composite material prepared by the preparation method according to claim 8 in the preparation of polymer bearings.

Images