Polymer nanomicrospheres, preparation method and application thereof
Polymer nanospheres with a particle size of less than 30 nm prepared by emulsion polymerization have solved the problems of poor dispersibility and corrosion of traditional lubricating oil additives under harsh conditions, and have achieved a significant improvement in the oxidation resistance and wear resistance of lubricating oil.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-17
- Publication Date
- 2026-06-19
AI Technical Summary
Traditional lubricant additives tend to generate acidic products during use, leading to corrosion of friction surfaces, and their lubrication performance is poor under harsh conditions. Nanoparticles also have poor dispersibility in base oils, limiting their application.
Polymer nanospheres with a particle size of less than 30 nm were prepared by emulsion polymerization. Stable nanospheres were prepared by using styrene, crosslinking agent, surfactant, pore-forming agent, initiator and water as raw materials. These nanospheres can be used as lubricating oil additives to improve the oxidation resistance and wear resistance of the lubricating oil.
Polymer nanospheres exhibit good oxidation resistance and anti-wear properties in lubricating oils, especially showing excellent lubrication and anti-wear performance during the transition from low to high loads, significantly improving the lubrication performance of base oils.
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Figure CN122234281A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lubricant additives, and more particularly to a polymer nanosphere, its preparation method, and its application. Background Technology
[0002] Nanoparticles, defined as particles with a diameter of less than 100 nm, improve fuel efficiency, engine performance, exhaust emissions, combustion, and evaporation characteristics. Furthermore, nanoparticles can reduce energy consumption and increase heat transfer. They are thermally stable at high temperatures, making them more stable as lubricant additives. While traditional lubricant additives can improve the frictional properties of oils, they also have significant drawbacks. For example, due to their inherent structure, they can generate acidic products when exposed to water, leading to corrosion of the friction surfaces. Additionally, environmental conditions exceeding the compound's tolerance can alter its chemical structure or morphology, producing substances detrimental to lubrication and disrupting the lubrication atmosphere. Due to quantum size and surface effects, nanomaterials exist on friction surfaces in the form of nanoparticles or nanofilms, exhibiting excellent lubricity and friction-reducing properties. Using nanoparticles as friction reducers in lubricants, especially under harsh conditions, can significantly improve the lubrication performance and load-carrying capacity of base oils, reduce the amount of additives needed, and improve product quality.
[0003] Based on existing research findings and application results, adding solid nano-lubricant particles to mineral base oils to form solid-liquid phase fluid lubricants can combine the advantages of solid lubrication and fluid lubrication, expanding the application range of oils and solving lubrication problems under special working conditions. However, due to their large particle size, solid particles have poor oil solubility and poor dispersion stability in base oils, easily agglomerating, thus limiting the application of such additives in lubricating oil products. Nanopolymer microspheres have the characteristics of controllable size, regular morphology, and easy surface modification, and exhibit good dispersion stability in oils. Unlike bulk polymerization, solution polymerization, and suspension polymerization, emulsion polymerization can simultaneously achieve high molecular weight polymers and high reaction rates. The polymerization system usually uses water as a medium, which facilitates heat dissipation, is environmentally friendly, and eliminates the hassle of solvent recovery.
[0004] The development and research of novel lubricating oil additives, as well as the study of the physicochemical changes of these additives during friction, are important interdisciplinary topics in the fields of chemistry, tribology, materials science, and mechanics. Applying nanomaterials to lubricating oil systems represents a novel research area. Using polymer nano-lubricating oil additives as extreme pressure anti-wear agents to replace those containing organic compounds such as S, P, and Cl may offer hope for solving the corrosion and environmental problems caused by S, P, and Cl in metal equipment. Currently, there is an urgent need to provide a novel polymer nanosphere with both anti-wear and anti-oxidation properties. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides polymer nanospheres, their preparation method, lubricant functional agents, and applications. The polymer nanospheres provided by this invention, as lubricant functional agents, exhibit excellent antioxidant and anti-wear properties.
[0006] In a first aspect, the polymer nanospheres provided by the present invention comprise the following raw materials in parts by weight: 10-20 parts monomer, 30-50 parts crosslinking agent, 0.001-2 parts surfactant, 0.005-1 part pore-forming agent, 0.001-1 part initiator, and 20-50 parts water; wherein the monomer is styrene; and the particle size of the polymer nanospheres is less than 30 nm. In this invention, the polymer nanospheres obtained from a certain amount of styrene, crosslinking agent, surfactant, pore-forming agent, initiator, and water can be stably dispersed in base oil. By using these nanospheres as a lubricating oil additive, the oxidation resistance and anti-wear properties of the oil can be significantly improved.
[0007] Preferably, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, trimethylolpropane triacrylate, divinylbenzene, and pentaerythritol tetraacrylate.
[0008] More preferably, the crosslinking agent is divinylbenzene.
[0009] Preferably, the mass ratio of divinylbenzene to styrene is 15-18:30-35. Nanospheres obtained using preferred types and proportions of monomers and crosslinking agents exhibit better modification effects.
[0010] Preferably, the polymer nanospheres have a particle size of 1-25 nm, more preferably 1-10 nm. Adding polymer nanospheres with the preferred nanoparticle size to base oil can better improve the oil's antioxidant and anti-wear properties.
[0011] Preferably, the surfactant is selected from one or two of span20, span40, span60, and span80, with span80 being the most preferred.
[0012] Preferably, the pore-forming agent is toluene.
[0013] Preferably, the initiator is one of 1-hydroxy-cyclohexylphenyl ketone, benzoin dimethyl ether, 4-chlorobenzophenone, azobisisobutyronitrile, azobisisovalerate, dicumyl peroxide, and tert-butyl peroxide, and is more preferably azobisisobutyronitrile.
[0014] Preferably, the product also includes an antioxidant; preferably, the antioxidant is an alkyl diphenylamine.
[0015] This invention prepares an oil-in-water emulsion by using selected raw materials such as styrene, crosslinking agent, surfactant, pore-forming agent, initiator, and alkyl diphenylamine as the internal phase and water as the external phase. The emulsion is then thermally initiated to polymerize, yielding nanopolymer microspheres of a specific particle size, which further improves the oxidation resistance and anti-wear properties of the oil. This invention, through the use of monomers, crosslinking agents, and selected surfactants, pore-forming agents, initiators, and antioxidants in specific amounts, obtains polymer nanospheres with a specific nanoparticle size. These nanospheres, acting as functional agents in lubricating oils, exhibit excellent oxidation resistance and anti-wear properties, demonstrating good anti-wear performance throughout the entire load range from low to high. Mechanism analysis shows that under low loads, the oil film adsorbed on the surface of the nanospheres and the elastic "rolling" of the microspheres work together to provide lubrication and anti-wear. Under high loads, the oil film ruptures, the microspheres deform and melt into a polymer lubricating film, thus exhibiting good anti-wear performance throughout the entire load range.
[0016] Further preferably, the polymer nanospheres comprise the following raw materials in parts by weight: 15-18 parts monomer, 30-35 parts crosslinking agent, 0.001-2 parts surfactant, 0.005-1 part porogen, 0.001-1 part initiator, 0-10 parts antioxidant, and 20-30 parts water. More preferably, the composition is: 15-18 parts monomer, 30-35 parts crosslinking agent, 0.5-1 part surfactant, 0.8-1 part porogen, 0.01-0.25 parts initiator, 0.01-5 parts antioxidant, and 20-30 parts water. Using the above-mentioned raw materials in preferred amounts enables the polymer nanospheres to have a nanoparticle size and better overall performance. Most preferably, the composition is: 15 parts styrene, 30 parts divinylbenzene, 0.5 parts Span 80, 1 part toluene, 0.25 parts azobisisobutyronitrile, 5 parts alkyl diphenylamine, and 20 parts deionized water.
[0017] Secondly, the present invention provides a method for preparing the polymer nanospheres, comprising: mixing monomers, crosslinking agents, surfactants, pore-forming agents, initiators, and optionally antioxidants to obtain an oil phase; adding the oil phase to water under stirring to obtain an emulsion; and polymerizing and drying the emulsion. The emulsion polymerization method used in this invention can synthesize polymer nanospheres that are stably dispersed in lubricating oil base oils, and these polymer nanospheres can significantly improve the oxidation resistance and anti-wear properties of lubricating oils.
[0018] Preferably, the stirring speed is 800~1500 r / min; preferably, the oil phase is added to the water dropwise, and stirring continues for 5~15 min after the dropwise addition is completed. This invention improves the properties of polymer microspheres through stirring. The research found that stirring under certain conditions can enhance the antioxidant properties of polymer nanospheres. Optimized stirring speed can better ensure the uniform dispersion of antioxidants in the aqueous phase and the size of the microspheres. Too low a stirring speed leads to uneven dispersion of antioxidants, while too high a speed causes emulsion instability and increases the microsphere size; both of these conditions result in reduced antioxidant properties.
[0019] Preferably, the polymerization temperature is 70~90℃ and the time is 20~30h; and / or, the drying temperature is 100~150℃. Preferably, polymerization is carried out in a water bath at 80±5℃ for 24±2h, followed by drying in a drying oven at 120±10℃.
[0020] According to a preferred embodiment of the present invention, a lubricating oil functional agent consisting of polymer nanospheres with antioxidant and anti-wear properties is prepared by oil-in-water (O / W) high internal phase emulsion polymerization. The monomers, antioxidants, crosslinking agents, surfactants, toluene, and initiators are used as the oil phase, and deionized water is used as the aqueous phase. Under continuous stirring at a certain rotation speed, the oil phase containing the above substances is added dropwise to the aqueous phase in a round-bottom flask using a syringe. After the oil phase addition is complete, stirring is continued for a certain period of time to obtain a stable emulsion. The emulsion preparation process is described below. Figure 1 The prepared emulsion was poured into a container and polymerized in a water bath at a specific temperature, eventually yielding a white, blocky polymer. The polymer was then dried at high temperature to remove remaining water, toluene (the pore-forming agent), unreacted monomers, and crosslinking agents. After drying to constant weight, the polymer was removed and crushed in a mortar to obtain nanospheres suitable for use in lubricating oils. Scanning electron microscopy (SEM) analysis showed that the nanospheres had a diameter of 1–10 nm. Adding these nanospheres to lubricating oil base oils significantly improved their oxidation resistance and anti-wear properties; an addition of 0.07 wt.% resulted in optimal oxidation resistance and anti-wear properties.
[0021] Thirdly, the present invention provides the application of the above-described polymer nanospheres or polymer nanospheres prepared by the above-described preparation method as lubricating oil functional agents. The present invention also provides a lubricating oil containing the above-described polymer nanospheres.
[0022] Further preferably, the mass content of the polymer nanospheres in the lubricating oil is 0.05%~3%, more preferably 0.06%~0.07%. The base oil in the lubricating oil is preferably an API Group II base oil. This invention has found that when the content of polymer nanospheres in the lubricating oil is 0.05%~3%, the polymer nanospheres can improve the oxidation resistance and anti-wear properties of the base oil. In particular, when the mass fraction of the polymer nanospheres is 0.06%~0.07%, more preferably 0.07%, the oil exhibits optimal oxidation resistance and anti-wear properties.
[0023] The polymer nanospheres provided by this invention are obtained by thermally initiating emulsion polymerization of an oil-in-water emulsion using selected monomers, crosslinking agents, and other raw materials as the internal phase and water as the external phase to obtain nanopolymer nanospheres of a specific particle size. When these polymer nanospheres are added to base oils, they act as a lubricating oil additive, significantly improving the oil's antioxidant and anti-wear properties. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a schematic diagram of the emulsion preparation process provided by the present invention.
[0026] Figure 2 This is a SEM image of the polymer nanospheres provided in Example 1 of the present invention.
[0027] Figure 3 The test results are for the high-frequency reciprocating test machine provided in Embodiment 1 of the present invention. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0029] Unless otherwise specified, specific techniques or conditions in the embodiments of this invention shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Devices, instruments, reagents, etc., whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels. All raw materials used in this invention are readily available in the domestic market.
[0030] Example 1 This embodiment provides a polymer nanosphere made of the following raw materials: 3g styrene, 6g divinylbenzene, 0.1g Span80, 0.2g toluene, 0.05g azobisisobutyronitrile, 1g alkyl diphenylamine, and 4g deionized water.
[0031] This embodiment also provides a method for preparing the polymer nanospheres, as follows: (1) Weigh 3g of styrene, 1g of alkyl diphenylamine, 6g of divinylbenzene, 0.1g of Span 80, 0.2g of toluene, and 0.05g of azobisisobutyronitrile as the oil phase. Use 4g of deionized water as the aqueous phase. Under continuous stirring at 1000r / min, use a syringe to dropwise add the oil phase containing the above substances into the aqueous phase in a round-bottom flask. After the oil phase is added, continue stirring for 10min to obtain a stable emulsion.
[0032] (2) The prepared emulsion was poured into a container and polymerized in an 80°C water bath for 24 hours, eventually yielding a white, blocky polymer. The polymer was then dried in a 120°C drying oven until constant weight was achieved. After drying, the polymer was removed and crushed in a mortar and pestle to obtain polymer nanospheres. Figure 2 The polymer nanospheres obtained in Example 1 have a particle size of 1~10 nm.
[0033] Example 2 This embodiment provides a polymer nanosphere made of the following raw materials: 3g styrene, 6g divinylbenzene, 0.1g Span 80, 0.2g toluene, 0.05g azobisisobutyronitrile, and 4g deionized water.
[0034] This embodiment also provides a method for preparing the polymer nanospheres, as follows: (1) Weigh 3g of styrene, 6g of divinylbenzene, 0.1g of Span 80, 0.2g of toluene, and 0.05g of azobisisobutyronitrile as the oil phase. Weigh 4g of deionized water as the aqueous phase. Under continuous stirring at 1000r / min, use a syringe to dropwise add the oil phase containing the above substances into the aqueous phase in a round-bottom flask. After the oil phase is added, continue stirring for 10min to obtain a stable emulsion.
[0035] (2) Pour the prepared emulsion into a container and place the container in an 80°C water bath for polymerization for 24 hours to obtain a white block polymer. Further dry the polymer in a 120°C drying oven until it reaches a constant weight, then take it out and crush it with a mortar to obtain polymer nanospheres with a particle size of 1~10 nm.
[0036] Example 3 This embodiment provides a polymer nanosphere made of the following raw materials: 3g styrene, 2g alkyl diphenylamine, 6g divinylbenzene, 0.1g Span 80, 0.2g toluene, 0.05g azobisisobutyronitrile, and 4g deionized water.
[0037] This embodiment also provides a method for preparing the polymer nanospheres, as follows: (1) Weigh 3g of styrene, 2g of alkyl diphenylamine, 6g of divinylbenzene, 0.1g of Span 80, 0.2g of toluene, and 0.05g of azobisisobutyronitrile as the oil phase. Weigh 4g of deionized water as the aqueous phase. Under continuous stirring at 1000r / min, use a syringe to dropwise add the oil phase containing the above substances into the aqueous phase in a round-bottom flask. After the oil phase is added, continue stirring for 10min to obtain a stable emulsion.
[0038] (2) Pour the prepared emulsion into a container and place the container in an 80°C water bath for polymerization for 24 hours to obtain a white block polymer. Further dry the polymer in a 120°C drying oven until it reaches a constant weight, then take it out and crush it with a mortar to obtain polymer nanospheres with a particle size of 1~10 nm.
[0039] Example 4 This embodiment provides a polymer nanosphere and its preparation method, which differs from Example 1 in that: (1) Weigh 3g of styrene, 6g of divinylbenzene, 0.1g of Span 80, 0.2g of toluene, 0.05g of azobisisobutyronitrile, and 1g of alkyl diphenylamine as the oil phase. Use 4g of deionized water as the aqueous phase. Under continuous stirring at 500r / min, use a syringe to dropwise add the oil phase containing the above substances into the aqueous phase in a round-bottom flask. After the oil phase is added, continue stirring for 10min to obtain a stable emulsion.
[0040] (2) Pour the prepared emulsion into a container and place the container in an 80°C water bath for polymerization for 24 hours to obtain a white block polymer. Further dry the polymer in a 120°C drying oven until it reaches a constant weight, then take it out and crush it with a mortar to obtain polymer nanospheres with a particle size of 1~10 nm.
[0041] Example 5 This embodiment provides a polymer nanosphere and its preparation method, which differs from Example 1 in that: (1) Weigh 3g of styrene, 6g of divinylbenzene, 0.1g of Span 80, 0.2g of toluene, 0.05g of azobisisobutyronitrile, and 1g of alkyl diphenylamine as the oil phase. Use 4g of deionized water as the aqueous phase. Under continuous stirring at 2000r / min, use a syringe to dropwise add the oil phase containing the above substances into the aqueous phase in a round-bottom flask. After the oil phase is added, continue stirring for 10min to obtain a stable emulsion.
[0042] (2) Pour the prepared emulsion into a container and place the container in an 80°C water bath for polymerization for 24 hours to obtain a white block polymer. Further dry the polymer in a 120°C drying oven until it reaches a constant weight, then take it out and crush it with a mortar to obtain polymer nanospheres with a particle size of 1~10 nm.
[0043] Example 6 This embodiment provides a polymer nanosphere and its preparation method. The difference from Example 1 is that span80 in the raw materials is replaced with span20, and the amount of alkyl diphenylamine is changed to 2g.
[0044] Example 7 This embodiment provides a polymer nanosphere and its preparation method. The difference from Example 1 is that styrene in the raw materials is replaced with methyl methacrylate, and the amount of alkyl diphenylamine is changed to 2g.
[0045] Example 8 This embodiment provides a polymer nanosphere and its preparation method. The difference from Example 1 is that the divinylbenzene in the raw materials is replaced with ethylene glycol dimethacrylate, and the amount of alkyl diphenylamine is changed to 2g.
[0046] Comparative Example 1 The only difference between this comparative example and Example 1 is that styrene in the raw materials is replaced with methyl methacrylate.
[0047] Comparative Example 2 The only difference between this comparative example and Example 1 is that water is replaced with ethanol, and the particle size of the polymer nanospheres is ≤100nm.
[0048] Comparative Example 3 The only difference between this comparative example and Example 1 is that the amount of styrene added is 30g, the amount of divinylbenzene is 60g, and the particle size of the polymer nanospheres is ≤100nm.
[0049] In the experimental examples of this invention, the rotating oxygen bomb test of the oil was conducted according to SH / T 0193. The high-frequency reciprocating test (HFRR) of the oil involved a steel ball sliding back and forth on a steel disc under a load of 392 N, at a frequency of 50 Hz and a stroke of 1 mm. The test lasted for 90 minutes, and the wear scar diameter was obtained.
[0050] The polymer nanospheres prepared by the method in Example 1 were added to API Group II base oils at different mass fractions as shown in Table 1. The mixtures were stirred for 2 hours at 55°C and 500 rpm, and then subjected to rotating bomb oxidation and high-frequency reciprocating (HFRR) tests to obtain the oxidation resistance and anti-wear properties of the resulting oils. The test results are shown in Table 1. The effect of different polymer nanosphere addition amounts on the rotating bomb oxidation data of the oils showed that the oil reached the maximum rotating bomb oxidation value when the addition amount of polymer nanospheres was 0.07%, and the value did not increase further with increasing polymer nanosphere addition. When the addition amount of polymer nanospheres was 0.07%, the oil had the smallest average wear scar diameter and exhibited the best anti-wear properties. The steel ball wear scar photographs and average wear scar diameter obtained from the above high-frequency reciprocating (HFRR) test of the oil from Example 1 are shown in Table 1. Figure 3 .
[0051] Table 1
[0052] The polymer nanospheres prepared by the methods of Examples 1-8 and Comparative Examples 1-3 were added to API Group II base oils at the mass fractions shown in Table 2. The mixtures were stirred for 2 hours at 55°C and 500 r / min. Then, the oils were subjected to rotating bomb oxidation (SH / T0193) and high-frequency reciprocating tests to obtain the oxidation resistance and anti-wear properties of the resulting oils. The test results are shown in Table 2.
[0053] Table 2
[0054] Comparing the rotating bomb oxidation test results of Comparative Example 1 and Example 1, it can be seen that replacing styrene with methyl methacrylate in the raw materials reduces the antioxidant performance of the nanospheres. This may be because the emulsion prepared with methyl methacrylate monomer is not as stable as that prepared with styrene. The high-temperature water bath operation during emulsion polymerization can damage the stability of the emulsion, leading to oil-water separation and reducing the antioxidant content in the nanospheres. Comparing Comparative Examples 2-3 with Example 1 also shows that polymer nanospheres prepared using different raw materials or dosages have a significant impact on the antioxidant performance of the oil. Comparing Examples 2-3 with Example 1, it can be seen that when no antioxidant alkyl diphenylamine is added to the oil phase, the rotating bomb oxidation value obtained from the oil test is comparable to that of pure API Group II base oil. This indicates that alkyl diphenylamine is a key influencing factor in enhancing the antioxidant performance of polymer nanospheres, and the alkyl diphenylamine in Example 1 represents the optimal addition amount. A comparison of Examples 4-5 with Example 1 shows that the stirring speed during emulsion preparation has a significant impact on the antioxidant properties of polymer nanospheres. This is because the stirring speed determines the degree of antioxidant dispersion and the particle size of the final polymer nanospheres. If the stirring speed is too low, the antioxidant in the oil phase cannot be uniformly dispersed in the aqueous phase; if the stirring speed is too high, the emulsion becomes unstable, resulting in excessively large nanospheres. Both of these conditions reduce the antioxidant properties of the nanospheres. A comparison of Examples 6-8 with Example 1 shows that even after changing the surfactant, single agent, or crosslinking agent, increasing the dosage of the antioxidant alkyl diphenylamine does not achieve the optimal rotational bomb value. This is related to the stability of the emulsion system. The more stable the emulsion, the more uniform the size of the prepared polymer nanospheres, the more uniformly the alkyl diphenylamine antioxidant is dispersed in the polymer nanospheres, the higher the rotational bomb value, and the better the antioxidant properties of the oil. The anti-wear performance of Examples 1-8 and Comparative Examples 1-3 was tested. The wear scar diameter data of the steel balls after the HFRR test showed that the anti-wear performance of Examples 1-8 was significantly better than that of Comparative Examples 1-3. Moreover, even if the amount of polymer nanospheres added in the oil was the same, the difference in wear scar diameter was still large. It can be seen that the anti-wear performance of polymer nanospheres is significantly different. This is mainly because the different types and amounts of components added during the emulsion preparation process have a great influence on the stability of the emulsion, which in turn affects the morphology and internal composition of the polymer nanospheres, thus exhibiting different anti-wear performance.
[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A polymeric nanosphere, characterized in that, The raw materials include the following parts by weight: 10-20 parts monomer, 30-50 parts crosslinking agent, 0.001-2 parts surfactant, 0.005-1 part porogen, 0.001-1 part initiator, and 20-50 parts water; the monomer is styrene; the particle size of the polymer nanospheres is less than 30 nm.
2. The polymeric nanospheres according to claim 1, characterized in that, The polymer nanospheres have a particle size of 1~25nm, preferably 1~10nm.
3. The polymer nanospheres according to claim 1 or 2, characterized in that, The crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, trimethylolpropane triacrylate, divinylbenzene, and pentaerythritol tetraacrylate.
4. The polymer nanospheres according to claim 3, characterized in that, The crosslinking agent is divinylbenzene; preferably, the mass ratio of divinylbenzene to styrene is 15~18:30~35.
5. The polymer nanospheres according to any one of claims 1-4, characterized in that, The surfactant is selected from one or two of span20, span40, span60, and span80; and / or, the porogen is toluene; and / or, the initiator is one of 1-hydroxy-cyclohexylphenyl ketone, benzoin dimethyl ether, 4-chlorobenzophenone, azobisisobutyronitrile, azobisisovalerate, dicumyl peroxide, and tert-butyl peroxide.
6. The polymer nanospheres according to any one of claims 1-5, characterized in that, It also includes antioxidants; preferably, the antioxidant is alkyl diphenylamine.
7. The polymer nanospheres according to claim 6, characterized in that, The raw materials include the following parts by weight: 15-18 parts monomer, 30-35 parts crosslinking agent, 0.001-2 parts surfactant, 0.005-1 part pore-forming agent, 0.001-1 part initiator, 0-10 parts antioxidant, and 20-30 parts water.
8. The method for preparing the polymer nanospheres according to any one of claims 1-7, characterized in that, include: The monomer, crosslinking agent, surfactant, porogen, initiator, and optional antioxidant are mixed to obtain an oil phase. The oil phase is then added to water under stirring to obtain an emulsion. The emulsion is then polymerized and dried.
9. The method for preparing polymer nanospheres according to claim 8, characterized in that, The stirring speed is 800~1500 r / min; and / or the polymerization temperature is 70~90℃ and the time is 20~30h; and / or the drying temperature is 100~150℃.
10. The application of the polymer nanospheres according to any one of claims 1-7 or the polymer nanospheres prepared by the preparation method according to claim 8 or 9 as a lubricating oil functional agent; preferably, the mass content of the polymer nanospheres in the lubricating oil is 0.05%~3%, more preferably 0.06%~0.07%.