A macroporous nanosilica composite material and a preparation method thereof

Abstract

The application belongs to the technical field of nanocomposites, and particularly relates to a macroporous nanosilica composite material and a preparation method thereof. The macroporous nanosilica composite material comprises nanomacroporous silica and a lubricating additive loaded in the silica material; the nanomacroporous silica has a particle size of 50-110 nm and a pore size of 3-30 nm. The application optimizes and adjusts raw materials and a preparation process, so that the nanosilica composite material has excellent tribological and lubricating properties and can meet the application requirements in the self-lubricating field. The preparation method of the application has simple raw materials, mild process conditions, and no need for complex equipment, and is very convenient for industrial production. The preparation method of the application is simple in operation, low in production cost, and suitable for industrial production. The prepared product has certain stability, excellent lubricating property, and wide application range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanocomposites, and particularly relates to a macroporous nanosilica composite material and a preparation method thereof. BACKGROUND

[0002] Friction is a common phenomenon in daily life, and is inevitable in the motion system. Adding a lubricant between the frictional contact surfaces of relative motion is an effective means to reduce friction and wear, which effectively avoids unnecessary material loss and economic loss caused by friction.

[0003] In addition, adding a lubricant between the interacting mating surfaces can play a role in bearing load, reducing the friction coefficient between the mating surfaces, and reducing the material wear of the mating surfaces. Among them, liquid lubricants are the most widely used and the most diverse types of lubricants. They can easily form a hydrodynamic film on the mating surface, hinder the direct contact of the friction pair, and have good heat dissipation and flushing effects. However, existing liquid lubricants still have performance limitations when used in special application scenarios such as oil-free, high and low temperature, corrosion prevention, stain prevention, radiation prevention, etc. Especially when used in space environments, problems such as degradation, thickening, carbonization, creep, and leakage often occur.

[0004] Nanosilica material as a lubricant additive can effectively improve the comprehensive performance of the lubricant. On the one hand, it can form a thin film with low friction coefficient on the friction surface to fill and repair the friction surface. On the other hand, due to its small size and spherical morphology, it can act as a micro-bearing and polish and strengthen the friction surface, effectively improving the load-carrying capacity and friction-reducing and wear-resistant performance of the lubricant, and is beneficial to widening the application of the lubricant in harsh working conditions such as heavy load and high temperature.

[0005] In previous research work, the inventors prepared a hierarchically porous silica material doped with boron in situ by a template method, and the material significantly improved the lubricating performance of the lubricating oil as an additive (Chinese Patent CN116715246A). In addition, the inventors also stored lubricating oil in mesoporous silica nanoparticles with an average pore size of 12.8 nm (Chinese Patent CN115948191A). Benefiting from the rich mesoporous structure of the silica, the lubricant stored in the pore can be released to the friction mating surface under the action of load and friction heat, thereby playing a lubricating role, and avoiding the problem that the lubricating oil used in space environments is prone to deterioration under atomic oxygen or proton irradiation, resulting in a short service life of the lubricating oil.

[0006] However, due to the small pore size of mesoporous silica, the type of stored lubricant is limited by the viscosity and type of lubricating oil. In particular, for the loading of solid nanoparticle lubricants such as copper nanoparticles, molybdenum disulfide nanoparticles, copper sulfide nanoparticles, etc., due to the limitation of nanoparticle particle size, it is impossible to fill them into the pore channels of mesoporous silica materials.

[0007] Therefore, on the basis of the document (Yang Y N, Wan J J, Niu Y T, Gu Z Y, Zhang J, Yu MH. Structure-dependent and glutathione-responsive biodegradable dendritic mesoporous organosilica nanoparticles for safe protein delivery. Chem Mater 28(24): 9008-9016 (2016)), the pore size of mesoporous silica and the preparation method of the composite material are adjusted and optimized to obtain a nanosilica composite self-lubricating material with excellent performance. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a large-pore nanosilica composite material and a preparation method thereof, which has excellent tribological properties and lubricating properties by optimizing and adjusting the raw materials and preparation process, and can meet the application requirements in the self-lubricating field.

[0009] The present application also provides the application of the large-pore nanosilica composite material.

[0010] In order to achieve the above technical purpose, the present application adopts the following technical scheme:

[0011] A large-pore nanosilica composite material, comprising nanometer large-pore silica and a lubricating additive loaded in the nanometer large-pore silica; the nanometer large-pore silica has the advantages of small particle size, large pore size, high specific surface area and pore volume, and strong adsorption capacity; its rich pore structure has good storage capacity and certain stability; the lubricating performance is excellent and the application range is wide.

[0012] The large-pore nanosilica composite material has good corrosion resistance, excellent environmental adaptability, good self-lubricating performance, low density, high specific strength and other advantages, and has been widely used as a solid self-lubricating material in the fields of automobile industry and high-end technical equipment. For example, it is used to manufacture mechanical parts such as bearings, gears, seals, guide wheels, etc., to reduce wear and friction coefficient and improve mechanical efficiency.

[0013] Specifically, the nanoporous silica has a particle size of 50-110 nm and a pore size of 3-30 nm.

[0014] Specifically, the nanoporous silica composite material is prepared from a silicon source, a template agent, a pore-expanding agent, an organic amine catalyst, water, anhydrous ethanol, and a lubricating additive.

[0015] Specifically, the silicon source is one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, trimethoxysilane, and sodium silicate, and is preferably tetraethyl orthosilicate.

[0016] Specifically, the template agent is one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate, and is preferably sodium dodecylbenzenesulfonate.

[0017] Specifically, the pore-expanding agent is one or more of sodium salicylate, tributyl phosphate, and diethyl phthalate, and is further preferably sodium salicylate.

[0018] Specifically, the organic amine catalyst is one or more of octylamine, dodecylamine, ethanolamine, diethanolamine, and triethanolamine, and is further preferably triethanolamine.

[0019] Specifically, the lubricating additive is a liquid lubricant and / or a solid nanoparticle lubricating material.

[0020] Specifically, the liquid lubricant includes one or more of base oil, plant-based lubricating oil, ionic liquid, and perfluoropolyether lubricating oil.

[0021] Further preferably, the liquid lubricant is an ionic liquid [DBUH + ][9C - ], TIPAC 11 , or [DBNH + ][18C - ].

[0022] Specifically, the solid nanoparticle lubricating material is one or more of copper nanoparticles, copper sulfide nanoparticles, molybdenum disulfide nanoparticles, and magnetite nanoparticles.

[0023] Further, the present application also provides a preparation method of the nanoporous silica composite material, which comprises the following steps:

[0024] (1) dissolving the template agent and the pore-expanding agent in water and stirring at a certain temperature to obtain an organic composite template suspension;

[0025] adding an organic amine catalyst to the suspension, stirring for a period of time, then adding a silicon source, stirring for a period of time, and then adding anhydrous ethanol after the reaction system is naturally cooled to room temperature (25±5℃), stirring for a period of time, and then standing to obtain a mixed solution;

[0026] (2) centrifuging the mixed solution in step (1), washing and drying the solid product, and calcining in a muffle furnace to remove the organic complex template, thereby obtaining mesoporous nanosilica;

[0027] (3) soaking or immersing the mesoporous nanosilica in a solution or dispersion of a lubricating additive in a vacuum state for a period of time, removing excess anhydrous ethanol by rotary evaporation, and drying, thereby obtaining a macroporous nanosilica composite material.

[0028] Specifically, in step (1), the silicon source is one or more of tetramethyl orthosilicate, tetraethyl orthosilicate, trimethoxysilane, and sodium silicate, and is preferably tetraethyl orthosilicate.

[0029] Specifically, in step (1), the template agent is one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate, and is preferably sodium dodecylbenzenesulfonate.

[0030] Specifically, in step (1), the pore-expanding agent is one or more of sodium salicylate, tributyl phosphate, and diethyl phthalate, and is further preferably sodium salicylate.

[0031] Specifically, in step (1), the organic amine catalyst is one or more of octylamine, dodecylamine, ethanolamine, diethanolamine, and triethanolamine, and is further preferably triethanolamine.

[0032] Specifically, in step (3), the lubricating additive is a liquid lubricant and / or a solid nanoparticle lubricating material.

[0033] Specifically, the liquid lubricant includes one or more of base oil, plant-based lubricating oil, ionic liquid, and perfluoropolyether lubricating oil.

[0034] Further preferably, the liquid lubricant is an ionic liquid [DBUH + ][9C - ], TIPAC 11 , or [DBNH + ][18C - ].

[0035] Specifically, the solid nanoparticle lubricating material is one or more of copper nanoparticles, copper sulfide nanoparticles, molybdenum disulfide nanoparticles, and magnetite nanoparticles.

[0036] Specifically, in step (1), the reaction temperature of the template agent and the pore-expanding agent is 60-80℃, the stirring reaction time is 0.5-2h, preferably 1-2h, and further preferably 2h.

[0037] Specifically, in step (1), the mass ratio of the silicon source to the template agent is preferably 10-80:5-10, and further preferably 25-65:6-10.

[0038] Specifically, in step (1), the mass ratio of the silicon source to the pore-expanding agent is preferably 20-80:1-6, and further preferably 25-65:1-5.

[0039] Specifically, in step (1), the mass ratio of the silicon source to the organic amine catalyst is preferably 20-75:1-3, preferably 25-65:1.5-2.5, and further preferably 45-50:1.9-2.

[0040] Specifically, in step (1), after the organic amine catalyst is added to the suspension, the stirring reaction time is 0.5-2h, preferably 1-2h, and further preferably 1-1.5h, and the reaction temperature is 70-90℃, preferably 60-85℃, and further preferably 75-85℃.

[0041] Specifically, in step (1), after the silicon source is added to the suspension, the stirring reaction time is 1-4h, preferably 2-3h, and the reaction temperature is 70-90℃, preferably 60-85℃, and further preferably 75-85℃; the silicon source is added slowly, preferably by a constant-pressure funnel.

[0042] Specifically, in step (1), after the reaction system is naturally cooled to room temperature (25±5℃), the mass ratio of the anhydrous ethanol to the silicon source is preferably 4-20:1-3, and preferably 5-15:1.5-2.5; and the stirring reaction time after the anhydrous ethanol is added is 0.5-1h, and preferably 0.5h.

[0043] Specifically, in the preparation method, the cooling method is natural cooling.

[0044] Specifically, in step (2), the washing is performed with water and / or anhydrous ethanol, and the number of times of washing with the anhydrous ethanol is 3-5 times, and further preferably 3-4 times.

[0045] The number of times of washing with water is 3-5 times, and further preferably 3-4 times.

[0046] Specifically, in step (2), the anhydrous ethanol washing is preferably carried out under centrifugation, the rotation speed during centrifugation is 3000-8000 rpm, further preferably 4000-6000 rpm, and the centrifugation time is preferably 5-10 min.

[0047] Specifically, in step (2), the water washing is preferably carried out under centrifugation, the rotation speed during centrifugation is 3000-8000 rpm, further preferably 4000-6000 rpm, and the centrifugation time is preferably 5-10 min.

[0048] Specifically, in step (2), the drying method is heating drying or freeze drying, further preferably heating drying.

[0049] Specifically, in step (2), the drying temperature is 50-90℃, preferably 60-80℃, and the drying time is 10-24 h, preferably 10-12 h, further preferably 11-12 h.

[0050] Specifically, in step (2), the calcination temperature is 450-650℃, preferably 500-650℃, further preferably 550℃.

[0051] Specifically, in step (2), the calcination time is 3-7 h, further preferably 4-6 h, and more further preferably 5 h, starting from the time when the temperature rises to the calcination temperature.

[0052] Specifically, in step (2), the temperature rising rate from room temperature (25±5℃) to the calcination temperature during calcination is 5-15℃ / min, further preferably 10℃ / min.

[0053] Preferably, the calcination is preferably carried out in a muffle furnace; and the calcination atmosphere is preferably air.

[0054] Specifically, in step (3), the solution or dispersion of lubricating additives is a lubricating additive anhydrous ethanol solution or a lubricating additive anhydrous ethanol dispersion.

[0055] Specifically, in step (3), the mass ratio of mesoporous nanosilica and solution of lubricating additives is 1:0.5-10, further preferably 1:0.5-6, and more further preferably 1:3-6.

[0056] Specifically, in step (3), the ratio of mesoporous nanosilica and dispersion of lubricating additives is 1 g:(1.5-8) mL, further preferably 1 g:(1.6-6) mL.

[0057] Preferably, the concentration of the solution of lubricating additives is 2-8% (w / v), preferably 5% (w / v).

[0058] Preferably, the concentration of the dispersion of lubricant additives is 0.1-0.5 g / mL, preferably 0.2 g / mL.

[0059] Specifically, in step (3), the soaking method is preferably vacuum soaking, the vacuum degree of the vacuum soaking is -0.08 to -0.1 MPa, further preferably -0.1 MPa; the temperature of the soaking is preferably room temperature (25±5℃), and the time of the soaking is 3-6 h, further preferably 4-5 h.

[0060] Specifically, in step (3), the soaking method is preferably vacuum soaking, the vacuum degree of the vacuum soaking is -0.08 to -0.1 MPa, further preferably -0.1 MPa; the temperature of the soaking is preferably room temperature (25±5℃), and the time of the soaking is 3-6 h, further preferably 4-5 h.

[0061] Specifically, in step (3), the residual lubricant additives on the surface of the composite self-lubricating material can also be removed by washing.

[0062] Specifically, in step (3), the drying temperature is preferably 50-80℃, further preferably 60-80℃; and the drying time is preferably 8-24 h, further preferably 11-13 h.

[0063] Further, based on one general inventive concept, the present application also provides the use of the large-pore nanosilica composite material in the preparation of lubricants for the automobile industry or high-end equipment.

[0064] Further preferably, based on one general inventive concept, the present application also provides the use of the large-pore nanosilica composite material in the preparation of lubricants for mechanical parts such as bearings, gears, seals, guide wheels, etc.

[0065] Further, the present application also provides a method for testing the performance of the large-pore nanosilica composite material, which specifically comprises the following steps:

[0066] The large-pore nanosilica composite material is mixed with a water-alcohol system solvent, a dispersant is then added, and the tribological performance of the prepared large-pore nanosilica composite material is tested.

[0067] Specifically, the water-alcohol system is a mixed solvent of water and alcohol, and the mass ratio of the two is 1-2:2-1, further preferably 1:1; the alcohol is one or more of polyethylene glycol 400, polyethylene glycol 800, 1,3-propanediol and ethylene glycol, further preferably polyethylene glycol 800.

[0068] Specifically, the mass ratio of the macroporous nanosilica composite material to the water-alcohol system solvent is 1:(800-1000), preferably 1:1000.

[0069] Specifically, the dispersant is sodium dodecyl sulfate.

[0070] Specifically, the mass ratio of the macroporous nanosilica composite material to the dispersant is 1:(15-20), preferably 1:20.

[0071] Specifically, in the tribological performance test, the load is one or more of 98N, 196N and 392N, and is further preferably 196N.

[0072] In the tribological performance test, the rotation speed is one or more of 900r / min, 1200r / min and 1450r / min, and is further preferably 1450r / min.

[0073] In the tribological performance test, the test time is 10-30min, and is further preferably 30min.

[0074] Alternatively, as another preferred technical solution, the method for testing the performance of the macroporous nanosilica composite material comprises the following steps:

[0075] The macroporous nanosilica composite material is mixed with a binding agent, and then stirred at 40-50°C for 0.5-2 hours to form a suspension;

[0076] Then a curing agent is added to the suspension, stirred for 2-5 minutes, defoamed, and then cured at room temperature (25±5°C) for 1-3 hours, and then cured at 70-90°C for 10-15 hours to obtain a polymer; and then the tribological performance of the obtained polymer is tested.

[0077] Specifically, the binding agent is an epoxy resin.

[0078] Specifically, the mass ratio of the macroporous nanosilica composite material to the binding agent is 1:(5-12), preferably 1:10 or 1:5.

[0079] Specifically, the curing agent is triethylenetetramine.

[0080] Specifically, the mass ratio of the suspension to the curing agent is (6-10):1.

[0081] Specifically, in the tribological performance test, the load is one or more of 15N, 20N and 25N, and is further preferably 15N.

[0082] Specifically, the test time for the tribological performance test is 30-60 min, and is more preferably 60 min.

[0083] The preparation method provided by the application uses a complex formed by the interaction of an ionic surfactant and an ionic organic pore-expanding agent as a template, and under the catalysis of an organic amine, a hydrolysis and polycondensation reaction of a silicon source occurs at the template, and after removal of the template by high-temperature calcination, silica nanoparticles with a large pore size are obtained; the application mixes the prepared nano large-pore silica with a lubricating additive, and obtains a large-pore nano silica composite material loaded with the lubricating additive by soaking or impregnation treatment in a vacuum state.

[0084] Compared with the prior art, the application has the following advantages:

[0085] The large-pore nano silica composite material provided by the application comprises nano large-pore silica and a lubricating additive dispersed in the silica material.

[0086] The large-pore nano silica composite material provided by the application has a regular spherical morphology, a high specific surface area and a pore volume, good chemical and thermal stability, and can load a variety of lubricants with a high loading amount; the large-pore nano silica composite material combines the high mechanical strength and high wear resistance of the silica nanoparticles with the low friction of the lubricant, has a long service life, low friction and good service reliability, and can meet the requirements for low friction and high wear resistance of materials under harsh working conditions.

[0087] The application of the nano large-pore silica to the material is not limited by the viscosity of the lubricant due to the rich pore structure and large pore size of the nano large-pore silica. In addition, the rich large pores in the silica can also load a variety of solid nano lubricants, and the pore structure of the silica can make the solid nano lubricants uniformly distributed in the silica, avoiding the agglomeration of the nano particles due to too small particle size.

[0088] The preparation method of the application has simple raw materials, mild process conditions, and no need for complex equipment, and is very convenient for industrial production. The preparation method of the application is simple to operate, has low production cost, and is suitable for industrial production; the prepared product has certain stability, excellent lubricating performance, and a wide application range. BRIEF DESCRIPTION OF DRAWINGS

[0089] Figure 1 A transmission electron microscope image of the oil-loaded large-pore nano silica composite material described in Example 1;

[0090] Figure 2 Nitrogen adsorption-desorption isotherms and BJH pore size distribution graphs of the oil-loaded large-pore nano silica composite material described in Example 1, wherein, Figure 2(a) is nitrogen adsorption-desorption isotherm, Figure 2 (b) is BJH pore size distribution plot;

[0091] Figure 3 TGA plot of the oil-loaded macroporous nanosilica composite obtained in Example 1-3;

[0092] Figure 4 Comparison plot of four-ball friction data of Example 1 and Comparative Example 1;

[0093] Figure 5 Comparison plot of four-ball friction data of Example 2 and Comparative Example 1;

[0094] Figure 6 Comparison plot of four-ball friction data of Example 3 and Comparative Example 1;

[0095] Figure 7 Comparison plot of tribological properties of Example 4 and epoxy resin;

[0096] Figure 8 Plot of hardness data of Example 4 and epoxy resin;

[0097] Figure 9 Plot of contact angle data of Example 4 and epoxy resin;

[0098] Figure 10 Comparison plot of tribological properties of Example 5 and epoxy resin;

[0099] Figure 11 Plot of hardness data of Example 5 and epoxy resin;

[0100] Figure 12 Plot of contact angle data of Example 5 and epoxy resin. DETAILED DESCRIPTION

[0101] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0102] The instrument devices used in the following embodiments are all commercially available conventional instrument devices unless otherwise specified. The other reagents and materials used are all commercially available conventional reagents and materials unless otherwise specified. The experimental methods involved in the following embodiments are all conventional methods unless otherwise specified.

[0103] The room temperature in the following embodiments refers to 25±5℃.

[0104] The ionic liquid [DBUH+ ][9C - ]、TIPA C 11 、[DBNH + ][18C - The preparation method of ionic liquid is as follows (references for the preparation methods of the three ionic liquids: Yang SH, Shi YJ, Zuo XY, Zhang X. Tribological properties of the P and S-free protic ionic liquids as water-based lubricants, Journal of Molecular Liquids 414:126101(2024)):

[0105] 1. [DBUH] + ][9C - Preparation of ]

[0106]

[0107] Nonanoic acid and DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) were mixed in an equimolar ratio (the molar ratio of nonanoic acid to DBU was 1:1, and the amount of DBU used was generally 0.03-0.05 mol, but 0.04 mol was used here), and an appropriate amount (20-30 ml) of methanol was used as a solvent. The mixture was stirred uniformly at 25°C for 12 hours. The resulting mixture was then rotary evaporated at 40°C for 4 hours, and then dried in a vacuum drying oven at 40°C (vacuum degree of -0.1 MPa) for 6 hours to remove excess unevaporated methanol solvent.

[0108] 2. [DBNH] + ][18C - Preparation of ]

[0109]

[0110] Octadecic acid and DBN (1,5-diazabicyclo[4.3.0]-5-nonene) were mixed in an equimolar ratio (the molar ratio of octadecic acid to DBN was 1:1, and the amount of DBN used was generally 0.03-0.05 mol, but 0.04 mol was used here), and an appropriate amount (20-30 ml) of methanol was used as a solvent. The mixture was stirred uniformly at 25°C for 12 hours. The resulting mixture was then rotary evaporated at 40°C for 4 hours, and then dried in a vacuum drying oven at 40°C (vacuum degree of -0.1 MPa) for 6 hours to remove excess unevaporated methanol solvent.

[0111] 3. TIPA C 11 Preparation

[0112]

[0113] Mix undecanoic acid and triisopropanolamine in equimolar ratio (molar ratio of undecanoic acid to triisopropanolamine is 1:1, the general amount of triisopropanolamine is 0.03-0.05 mol, and the amount used here is 0.04 mol), and use an appropriate amount (20-30 ml) of acetonitrile as a solvent, and stir uniformly at 80°C for 12 hours. Then the obtained mixture is rotary evaporated at 40°C for 4 hours, and then placed in a vacuum drying oven (vacuum degree is -0.1 MPa) at 40°C for 6 hours to remove the unevaporated excess acetonitrile solvent, and the product is obtained.

[0114] Comparative Example 1

[0115] In 20 g of a mixed solvent of water / polyethylene glycol 800 (mass ratio of the two in the mixed solvent is 1:1), 0.4 g of a dispersant (sodium dodecyl sulfate) is added; then the tribological properties of the obtained product are tested by using a four-ball friction tester (MS-10A). The test conditions are room temperature (25±5°C), load 196 N, rotation speed 1450 r / min, and time 30 min.

[0116] Example 1

[0117] Example 1 provides a macroporous nanosilica composite material, which comprises nanomacroporous silica and a liquid lubricant located in the pore structure of the silica material, and a preparation method of the macroporous nanosilica composite material, and the specific steps are as follows:

[0118] 1) Dissolve 9.5 g of sodium dodecylbenzenesulfonate and 4.2 g of sodium salicylate in 625 g of water, stir and heat to 80°C for 2 h to obtain an organic complex template suspension; then add 1.90 g of triethanolamine, stir for 1 h, and then slowly drop 46.7 g of tetraethyl orthosilicate through a constant pressure funnel, continue to stir for 2 h; naturally cool to room temperature (25±5°C), add 235 g of anhydrous ethanol, stir for 30 min, and then stand still; centrifuge the obtained solution, and then wash with water and ethanol for 3 times respectively (the rotation speed of single centrifugal washing is 6000 rpm, and the time is 10 min), dry the obtained product at 60°C for 12 h, and then calcine in a muffle furnace at 550°C for 5 h; grind the calcined product into powder, and the mesoporous nanosilica is obtained;

[0119] 2) Dissolve the ionic liquid [DBUH + ][9C - ] in anhydrous ethanol to prepare a [DBUH + ][9C - ] ethanol solution with a concentration of 5% (w / v) for standby use;

[0120] The mesoporous nanosilica obtained in step 1) was placed in an ethanol solution of the ionic liquid [DBUH + ][9C - ] at a mass ratio of 1:5, and vacuumed (vacuum degree -0.1 MPa) for 4 h, then rotary evaporated for 6 h to remove the excess ethanol, and then dried in a blast oven at 60°C for 12 h to obtain the oil-loaded macroporous nanosilica composite, denoted as SiO2-DBUH 9C.

[0121] The ionic liquid used in Example 1 was [DBUH + ][9C - ], and its structure is as follows:

[0122]

[0123] Figure 1 The transmission electron micrograph of the oil-loaded macroporous nanosilica composite described in Example 1 is shown in Figure 1. Figure 1 As can be seen from Figure 1, the silica has a regular spherical morphology, with a particle size of 90-110 nm, and a large number of radial mesoporous channel structures in the interior of the particles.

[0124] Figure 2 The nitrogen adsorption-desorption isotherm (a) and the corresponding pore size distribution graph (b) of the oil-loaded macroporous nanosilica composite described in Example 1 are shown in Figure 2. Figure 2 As can be seen from Figure 2, the silica particles have mesoporous channel structures of 3-20 nm in the interior, and the specific surface area and pore volume of the material are 625 m 2 / g and 1.9 cm 3 / g, respectively.

[0125] The oil-loaded macroporous nanosilica composite prepared in Example 1 was subjected to performance testing, and Comparative Example 1 was subjected to the same testing, and the specific method was as follows:

[0126] 0.02 g of SiO2-DBUH 9C was added to 20 g of a mixed solvent of water / polyethylene glycol 800 (mass ratio of the two in the mixed solvent was 1:1), and 0.4 g of a dispersant (sodium dodecyl sulfate) was added; then a four-ball friction tester (MS-10A) was used to test the tribological properties of the prepared macroporous nanosilica composite, and the steel ball used in the test was a GCr15 bearing steel ball with a diameter of φ = 12.7 mm. The test conditions were room temperature (25±5°C), a load of 196 N, a rotation speed of 1450 r / min, and a time of 30 min.

[0127] Test results:

[0128] Figure 4 The friction data results of Example 1 and Comparative Example 1 are shown in Figure 3. Figure 4The friction coefficient of Comparative Example 1 is 0.015 in the early stage and about 0.012 in the later stage. After the oil-carrying macroporous nanosilica composite material SiO2-DBUH 9C is added, the friction coefficient is obviously reduced to 0.010.

[0129] Example 2

[0130] Example 2 provides an oil-carrying macroporous nanosilica composite material. In the preparation method of the oil-carrying macroporous nanosilica composite material in Example 2, step 1) is the same as that in Example 1. The difference between Example 2 and Example 1 is that the ionic liquid [DBUH + ][9C - ] in step 2) is replaced by TIPA C 11 , and the obtained oil-carrying macroporous nanosilica composite material is denoted as SiO2-TIPA C 11 .

[0131] The ionic liquid used in Example 2 is TIPA C 11 , and the structural formula is as follows:

[0132]

[0133] The oil-carrying macroporous nanosilica composite material prepared in Example 2 is subjected to performance testing, and the testing conditions are the same as those in Example 1. Comparative Example 1 is also subjected to the same testing.

[0134] Test results:

[0135] Figure 5 The friction data of Example 2 and Comparative Example 1 show that the friction coefficient of Comparative Example 1 is 0.015 in the early stage and about 0.012 in the later stage. After the oil-carrying macroporous nanosilica composite material SiO2-TIPA C 11 is added, the friction coefficient is obviously reduced to 0.010.

[0136] Example 3

[0137] Example 3 provides an oil-carrying macroporous nanosilica composite material. In the preparation method of the oil-carrying macroporous nanosilica composite material in Example 3, step 1) is the same as that in Example 1. The difference between Example 3 and Example 1 is that the ionic liquid [DBUH + ][9C - ] in step 2) is replaced by [DBNH + ][18C - ], and the obtained oil-carrying macroporous nanosilica composite material is denoted as SiO2-DBNH 18C.

[0138] The ionic liquid used in Example 3 is [DBNH +][18C - ] with the following structural formula:

[0139]

[0140] The oil-loaded macroporous nanosilica composite prepared in Example 3 was tested for performance under the same conditions as in Example 1, and Comparative Example 1 was tested in the same way.

[0141] Test results:

[0142] Figure 6 From the friction data for Example 3 and Comparative Example 1, it can be seen that the coefficient of friction of Comparative Example 1 was 0.015 in the early stage and about 0.012 in the later stage. After the addition of the oil-loaded macroporous nanosilica composite SiO2-DBNH 18C, the coefficient of friction was significantly reduced to 0.010.

[0143] Example 4

[0144] Example 4 provides a macroporous nanosilica composite material comprising nanomacroporous silica and a solid nanoparticle lubricating material located in the pore structure of the silica material, and a method for preparing the macroporous nanosilica composite material, wherein step 1) is the same as in Example 1, and the difference between Example 4 and Example 1 is that:

[0145] Step 2) is: dispersing copper nanoparticles (preparation method reference: Hua K Y, Shi Y J, Tang M M, Zuo XY, Gao J, Zhang X. In-situ surface modified water-soluble Cu nanoparticles as lubrication additives in water-based cutting fluids. Colloid Surfaces A 698: 134605-134615 (2024)) into anhydrous ethanol to prepare a copper nanoparticle dispersion with a concentration of 0.2 g / ml for standby use; the copper nanoparticles in this example serve as the solid nanoparticle lubricating material;

[0146] In 6 ml of the copper nanoparticle dispersion, add 10 ml of anhydrous ethanol for dilution, then take 3 g of the mesoporous nanosilica obtained in step 1) and the above diluted dispersion and place them in a three-necked flask and a constant-pressure funnel, respectively, and immerse them in a vacuum (vacuum degree -0.1 MPa) for 4 hours, then spin evaporation treatment for 6 hours to remove excess ethanol, and then place the product in a vacuum oven (vacuum degree -0.1 MPa) and dry it at 60°C for 12 hours, thereby obtaining a macroporous nanosilica composite material loaded with copper nanoparticles.

[0147] Performance test:

[0148] 1) The performance test was carried out on the copper nanoparticle-loaded macroporous nanosilica composite material prepared in Example 4, and pure epoxy resin was used as a control group. The specific method was as follows:

[0149] 1.0 g of the copper nanoparticle-loaded macroporous nanosilica composite material was mixed with 10 g of epoxy resin under stirring, and then a good suspension was formed after 1 hour of incubation and stirring at 45°C.

[0150] Then, 1.5 g of a curing agent (triethylenetetramine) was added to the suspension, and after 5 minutes of stirring, vacuum defoaming treatment was carried out, followed by pouring into a preheated mold (the mold was preheated to 60°C), curing at room temperature (25±5°C) for 2 hours, and then transferring to a vacuum oven (the vacuum degree was-0.1 MPa) for curing at 80°C for 12 hours, to obtain a polymer in which the epoxy resin was compounded with the macroporous nanosilica composite material. Then, the tribological performance was tested by a ball-on-disc multifunctional friction and wear tester, and the test conditions were room temperature (25±5°C), a load of 15 N, and a test time of 1 hour.

[0151] Test results:

[0152] Figure 7 The friction test results of pure epoxy resin and the polymer prepared in Example 4 are shown in Table 1. Figure 7 As shown in Table 1, the average friction coefficient of pure epoxy resin was 0.63 and did not change much over time. After the addition of the copper nanoparticle-loaded macroporous nanosilica composite material to the pure epoxy resin, the friction coefficient of the polymer was significantly reduced to 0.10 and did not fluctuate obviously.

[0153] 2) The hardness test was carried out on the copper nanoparticle-loaded macroporous nanosilica composite material prepared in Example 4, and pure epoxy resin was used as a control group. The test was carried out according to the method in the national standard GB / T2411-2008, and the specific method was as follows:

[0154] The sample was placed on a hard horizontal plane, and the hardness tester was held in a vertical position while the tip of the pressure pin was at least 9 mm away from the edge of the sample. The pressure seat was immediately applied to the sample without impact, so that the pressure seat was parallel to the sample and sufficient pressure was applied. The pressure seat and the sample should be in close contact, and then the value indicated by the indicating device was read.

[0155] Test results:

[0156] As shown in Table 2, the hardness of the copper nanoparticle-loaded macroporous nanosilica composite material was 0.45, and the hardness of pure epoxy resin was 0.55. After the addition of the copper nanoparticle-loaded macroporous nanosilica composite material to the pure epoxy resin, the hardness of the polymer was significantly reduced to 0.20 and did not fluctuate obviously. Figure 8As shown, the hardness of the pure epoxy resin sample and the composite self-lubricating material prepared in Example 4 were tested using a microhardness tester. The results showed that the hardness of the pure epoxy resin sample was significantly improved after adding the large-pore nano-silica composite material carrying copper nanoparticles, increasing from HV21 to HV52. Both copper nanoparticles and silica are polymer-reinforced fillers, which can improve the friction-reducing and wear-resistant properties of epoxy resin by increasing its hardness.

[0157] 3) The contact angle of the large-pore nano-silica composite material loaded with copper nanoparticles prepared in Example 4 was tested, with pure epoxy resin as a control group. The test was conducted according to the method in national standard GB / T30693-2014. The specific method is as follows:

[0158] Place the sample on the instrument's sample stage. Ensure the sample is placed flat and free of wrinkles or twists. Suspend a 5 μl water droplet at the tip of the needle. Raise the sample stage so that the sample surface contacts the suspended water droplet, then remove the sample to complete the water droplet transfer. Measure the contact angle within 60 seconds after the water droplet transfer.

[0159] Test results:

[0160] like Figure 9 As shown, contact angle tests revealed that adding a large-pore nano-silica composite material carrying copper nanoparticles to epoxy resin reduced the contact angle of the epoxy resin, improved its wettability to water-based lubricants under wet friction conditions, and facilitated the formation of a lubricating film.

[0161] Example 5

[0162] Example 5 provides a macroporous nano-silica composite material. The preparation method of the macroporous nano-silica composite material in Example 5 is the same as that in Example 4. The difference between Example 5 and Example 4 is that:

[0163] Performance testing:

[0164] 1) When testing the performance of the macroporous nano-silica composite material supported on copper nanoparticles prepared in Example 5, 2.0g of the macroporous nano-silica composite material supported on copper nanoparticles was mixed with 10g of epoxy resin, and pure epoxy resin was used as the control group.

[0165] Test results:

[0166] Figure 10 The results are from friction tests on pure epoxy resin and the polymer prepared in Example 5. Figure 10The average friction coefficient of pure epoxy resin is 0.62, and it does not change much over time. After adding the copper nanoparticle-loaded macroporous nanosilica composite material to the pure epoxy resin, the friction coefficient of the polymer is significantly reduced to 0.06 and does not fluctuate significantly.

[0167] 2) The hardness test was performed on the copper nanoparticle-loaded macroporous nanosilica composite material prepared in Example 5, and pure epoxy resin was used as a control group. The test was performed according to the method in the national standard GB / T2411-2008, and the specific method was as follows:

[0168] Place the sample on a hard horizontal plane, hold the hardness tester in a vertical position, and make the pressure pin tip at least 9 mm away from the edge of the sample. Immediately add the pressure seat to the sample without impact, make the pressure seat parallel to the sample and apply sufficient pressure, and then read the value indicated by the indicating device.

[0169] Test results:

[0170] As shown in Figure 11 , the hardness test of the pure epoxy resin sample and the composite self-lubricating material prepared in Example 5 was performed using a microhardness tester. The results showed that after adding the copper nanoparticle-loaded macroporous nanosilica composite material to the pure epoxy resin, the hardness of the sample was significantly improved from HV21 to HV60. As the content of copper nanoparticle-loaded macroporous nanosilica in the epoxy resin increased, the hardness of the sample prepared in Example 5 also increased.

[0171] 3) The contact angle test was performed on the copper nanoparticle-loaded macroporous nanosilica composite material prepared in Example 5, and pure epoxy resin was used as a control group. The test was performed according to the method in the national standard GB / T30693-2014, and the specific method was as follows:

[0172] Place the sample on the sample stage of the instrument. Ensure that the sample is placed flat without wrinkles and distortion. Hang a 5 μl water droplet at the end of the needle. Raise the sample stage to make the sample surface contact the hanging water droplet, then remove the sample to complete the transfer of the water droplet. Measure the contact angle within 60 s after the water droplet is transferred.

[0173] Test results:

[0174] As shown in Figure 12As shown, contact angle tests revealed that the contact angle of epoxy resin decreased after adding a large-pore nano-silica composite material carrying copper nanoparticles. As the amount of silica composite material added increased, the contact angle gradually decreased. This indicates that the wettability of epoxy resin to water-based lubricants under wet friction conditions can be adjusted by regulating the content of large-pore nano-silica carrying copper nanoparticles in the epoxy resin.

[0175] Table 1 shows the mass comparison of mesoporous nano-silica before and after adding liquid lubricant or solid nanoparticle lubricating material in Examples 1-5.

[0176] Table 1

[0177]

[0178] Figure 3 Thermogravimetric analysis (TGA) of the oil-loaded macroporous nano-silica composite materials obtained in Examples 1-3 is as follows: Figure 3 As can be seen, the mesoporous nano-silica contains the injected lubricating additive (ionic liquid [DBUH]). + ][9C - ]、TIPAC 11 、[DBNH + ][18C - The loading capacity of the ionic liquid is basically consistent with the results in Table 1.

[0179] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A macroporous nano-silica composite material, characterized in that, Includes nano-sized macroporous silica and lubricating additives loaded in the nano-sized macroporous silica; The nanoporous silica particles have a particle size of 50~110 nm and a pore size of 3~30 nm; The macroporous nano-silica composite material is prepared from silicon source, template agent, pore expander, organic amine catalyst, water, anhydrous ethanol, and lubricating additive; The silicon source is one or more of methyl orthosilicate, ethyl orthosilicate, trimethoxysilane, and sodium silicate; The template agent is one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfonate; The pore-expanding agent is sodium salicylate; The organic amine catalyst is one or more of octylamine, dodecylamine, ethanolamine, diethanolamine, and triethanolamine; The lubricating additive is a liquid lubricant or a solid nanoparticle lubricating material; The liquid lubricant is an ionic liquid [DBUH]. + ][9C - ]、TIPA C 11 or [DBNH + ][18C - ]; The solid nanoparticle lubricating material is one or more of the following: copper nanoparticles, copper sulfide nanoparticles, molybdenum disulfide nanoparticles, and iron oxide nanoparticles. The macroporous nano-silica composite material was prepared by the following steps: (1) Dissolve the template agent and the pore-expanding agent in water and stir the reaction at a certain temperature to obtain an organic complex template suspension; An organic amine catalyst was added to the suspension, and after stirring for a period of time, a silicon source was added. After stirring for another period of time, the reaction system was allowed to cool naturally to room temperature. Anhydrous ethanol was added, and after stirring for a period of time, the mixture was allowed to stand to obtain a mixed solution. (2) Centrifuge the mixed solution in step (1), wash and dry the solid product, and calcine it in a muffle furnace to remove the organic composite template, thereby obtaining mesoporous nano silica. (3) The mesoporous nano silica and the solution of lubricating additive or the dispersion of lubricating additive are soaked or impregnated in a vacuum for a period of time, and then the excess anhydrous ethanol is removed by rotary evaporation and dried to obtain the macroporous nano silica composite material.

2. The macroporous nano-silica composite material as described in claim 1, characterized in that, In step (1), the reaction temperature of the template agent and the pore-expanding agent is 60~80℃, and the stirring reaction time is 0.5~2h; In step (1), the mass ratio of the silicon source to the template agent is 10~80:5~10; In step (1), the mass ratio of the silicon source to the pore-expanding agent is 20~80:1~6; In step (1), the mass ratio of the silicon source to the organic amine catalyst is 20~75:1~3; In step (1), after adding the organic amine catalyst to the suspension, the stirring reaction time is 0.5~2h; the reaction temperature is 70~90℃. In step (1), after adding the silicon source to the suspension, the stirring reaction time is 1~4h; the reaction temperature is 70~90℃. In step (1), after the reaction system has cooled naturally to room temperature, when adding anhydrous ethanol, the mass ratio of anhydrous ethanol to silicon source is 4~20:1~3; after adding anhydrous ethanol, the stirring reaction time is 0.5~1h.

3. The macroporous nano-silica composite material as described in claim 1, characterized in that, In step (2), the washing is performed with water and / or anhydrous ethanol; In step (2), the drying temperature is 50~90℃ and the drying time is 10~24h; In step (2), the roasting temperature is 450~650℃; In step (2), the timer starts when the temperature rises to the roasting temperature, and the roasting time is 3~7h.

4. The macroporous nano-silica composite material as described in claim 1, characterized in that, In step (3), the solution or dispersion of the lubricating additive is an anhydrous ethanol solution or an anhydrous ethanol dispersion of the lubricating additive; the mass ratio of the mesoporous nano silica to the lubricating additive solution is 1:0.5~10; the ratio of the mesoporous nano silica to the lubricating additive dispersion is 1g:(1.5~8)mL. In step (3), the concentration of the lubricating additive solution is 2~8% w / v; the concentration of the lubricating additive dispersion is 0.1~0.5 g / mL.

5. The macroporous nano-silica composite material as described in claim 1, characterized in that, In step (2), the drying method is heating drying or freeze drying; in step (2), the drying temperature is 50~90℃ and the drying time is 10~24h.

6. The macroporous nano-silica composite material as described in claim 1, characterized in that, In step (3), the soaking method is vacuum soaking, the vacuum degree of the vacuum soaking is -0.08~-0.1MPa; the soaking temperature is room temperature, and the soaking time is 3~6h; In step (3), the impregnation method is vacuum impregnation, the vacuum degree of the vacuum impregnation is -0.08~-0.1MPa; the impregnation temperature is room temperature, and the impregnation time is 3~6h; In step (3), the drying temperature is 50~80℃; the drying time is 8~24h.

7. The application of the macroporous nano-silica composite material according to any one of claims 1 to 6 in the preparation of lubricants for the automotive industry or high-end equipment.

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