Special polyurea lubricating grease based on Ti3C2Tx / MoS2 nanocomposite
The special polyurea grease made of Ti3C2Tx/MoS2 nanocomposite material solves the problems of high friction coefficient, severe wear and insufficient lubrication life of traditional polyurea grease in high temperature environment, and achieves excellent lubrication performance and stability in high temperature environment of 250~320℃.
Patent Information
- Application Number
- CN202511377165.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-25
- Publication Date
- 2026-01-23
AI Technical Summary
Traditional polyurea greases have a high coefficient of friction, severe wear, and insufficient lubrication life under high temperature conditions. Furthermore, existing nano-additives are prone to failure and have poor dispersibility in oxidizing environments, making it difficult to meet the lubrication performance requirements of harsh working conditions.
Special polyurea grease was prepared by using Ti3C2Tx/MoS2 nanocomposite material, in-situ growth of MoS2 on Ti3C2Tx, combination with base oil of polyα-olefin and synthetic ester, and introduction of diisocyanate and amine to form polyurea thickener during the preparation process.
At a high temperature of 300℃, the coefficient of friction is reduced to 0.057~0.071, the wear scar diameter is 0.37~0.45mm, and the oil separation rate is 2.1~2.4wt%, which is significantly better than adding MoS2 or Ti3C2Tx powder alone, thus improving lubrication performance and stability.
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Figure CN121379685A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of polyurea grease and specifically relates to a special polyurea grease based on a Ti3C2T x / MoS2 nanocomposite. BACKGROUND
[0002] As a commonly used lubricating material in mechanical equipment, grease is widely used in the fields of aerospace, metallurgical processing, high-speed machine tools and energy equipment; polyurea grease has become one of the commonly used lubricating materials under high-temperature working conditions due to its excellent oxidation resistance, thermal stability and low volatile loss; however, the traditional polyurea grease still has problems such as high friction coefficient, serious wear and insufficient lubrication life when the friction pair is in an environment above 250 DEG C for a long time, and it is difficult to meet the harsh working conditions; in order to improve the high-temperature lubricating performance, the existing technology usually introduces solid lubricants such as MoS2, graphite, graphene, boron nitride, etc. into the grease to reduce friction and wear; although MoS2 with a layered structure exhibits excellent friction reduction characteristics under high-temperature conditions, it is easy to fail in an oxidizing environment, resulting in the attenuation of lubricating performance, and single nano additives are easy to agglomerate in the grease system, which limits the full play of the friction and wear reduction effect; in recent years, a new type of two-dimensional material MXene (such as Ti3C2T x ) has attracted attention due to its high specific surface area, excellent mechanical properties and good interface compatibility; although Ti3C2T x can provide certain friction reduction and strengthening effect in the grease, it still has the problem of insufficient structural stability under high-temperature environment; therefore, how to organically combine MXene with typical solid lubricants such as MoS2 to further improve the high-temperature wear resistance and stability of the grease has become a key technical problem to be solved. SUMMARY
[0003] The purpose of the application is to provide a special polyurea grease based on a Ti3C2T x / MoS2 nanocomposite.
[0004] The purpose of the application is achieved in that the special polyurea grease based on a Ti3C2T x / MoS2 nanocomposite comprises Ti3C2T xThe polyurea grease base is prepared from base oil 79-87wt%, diisocyanate 6-9wt%, amine 6-8wt%, antioxidant 0.5-2wt%, and anti-wear agent 0.5-2wt%, and the total amount of the raw materials is 100%; wherein the base oil is prepared by compounding poly-alpha-olefin and synthetic ester at a weight ratio of 75-85:15-25, and the total amount is 100 parts, and the synthetic ester is diisooctyl sebacate, dioctyl phthalate or neopentyl glycol dioctanoate; the amine is primary amine or secondary amine; and the preparation method is as follows: A, preparation of Ti3C2T x / MoS2 nanocomposite powder: A1, 1.5-2.5g Ti3AlC2 powder is added to 15-25mL aqueous solution containing 0.5-1.5g LiF and 5.5-6.5M HCl, and stirred at 34-36℃ for 23-25h; after the reaction is completed, the reaction solution is centrifuged and washed repeatedly with deionized water until pH=5.8-6.2, to obtain a solid-liquid weight ratio of 1:40-60 multilayer Ti3C2T x suspension; the multilayer Ti3C2T x suspension is ultrasonically treated at a power of 300-500W for 28-32min, and then freeze-dried at-40--60℃ for 24-36h to obtain fluffy Ti3C2T x powder; A2, 0.15-0.25g of the fluffy Ti3C2T x powder is dispersed in 36-44mL deionized water and 0.4-0.6g of ammonium tetrathiomolybdate is added, and the mixture is uniformly mixed to obtain mixture a; mixture a is transferred to a reaction kettle and hydrothermally reacted at 200-220℃ for 11-13h to obtain Ti3C2T x / MoS2 suspension; the Ti3C2T x / MoS2 suspension is centrifuged at a speed of 9000-11000rpm and washed with deionized water for 3-5 times, and then the solid part is freeze-dried at-40--60℃ for 24-36h to obtain Ti3C2T x / MoS2 nanocomposite powder; B, preparation of polyurea grease base: B1, according to the raw material ratio of the polyurea grease base, the base oil is placed in a stirring kettle and the antioxidant and anti-wear agent are added, heated to 85-95℃ and stirred at a speed of 150-250rpm for 25-35min, and fully dissolved and mixed to obtain mixture b; B2, under the protection of nitrogen, the raw materials of the polyurea grease base are proportioned, the diisocyanate is slowly dropped into the mixture b, then the amine is added and heated to 90-100 DEG C, and the mixture is stirred at a speed of 150-250 rpm for 1-2 hours, so that the mixture becomes a uniform colloid, then it is transferred to a high shear dispersion machine and stirred at a speed of 600-800 rpm for 20-30 minutes to obtain a mixture c; B3, the mixture c is heated to 115-125 DEG C and continuously stirred at a speed of 150-250 rpm for 0.8-1.2 hours, and then the product is sent to a three-roll mill for grinding for 2 or 3 times, the speed ratio of the three rollers in the three-roll mill is 1:3:9, to obtain a polyurea grease base; C, according to the proportion of the special polyurea grease, the Ti3C2T x / MoS2 nanocomposite powder is added into the polyurea grease base and uniformly mixed, and then it is sent to a three-roll mill for grinding for 2 or 3 times, the speed ratio of the three rollers in the three-roll mill is 1:3:9, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0005] The present application obtains the Ti3C2T x / MoS2 nanocomposite powder by in-situ growth of MoS2 on Ti3C2T x / MoS2 nanocomposite powder, and the polyurea thickening agent is formed by introducing diisocyanate and amine in the preparation of the polyurea grease base, so that the composition and state of the polyurea grease base are improved; the Ti3C2T x / MoS2 nanocomposite powder is compounded in the polyurea grease base according to a suitable proportion, and a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material is obtained.
[0006] Tests show that the special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material prepared by the present application has a friction coefficient of 0.057-0.071, a wear scar diameter of 0.37-0.45 mm and an oil exudation rate of 2.1-2.4 wt% at a high temperature of 300 DEG C (392 N, 1200 rpm), which is significantly better than that of a single MoS2 nanometer powder, Ti3C2T x nanometer powder and MoS2 nanometer powder / Ti3C2T x powder after conventional mixing; obviously, the preparation method of the present application realizes the organic combination of MXene and MoS2, and overcomes the problems of insufficient lubricating performance, wear resistance and stability of the existing polyurea grease in a high temperature environment, and can be applied in a high temperature environment of 250-320 DEG C. BRIEF DESCRIPTION OF DRAWINGS
[0007] Figure 1 Ti3C2T x / MoS2nanocomposite powder process schematic diagram; Figure 2 Ti3C2T x / MoS2nanocomposite powder morphology diagram under scanning electron microscope SEM; Figure 3 Polyurea grease base prepared in step B of examples 1~3, wherein (a) is magnified 10000 times, (b) is magnified 50000 times, morphology diagram under scanning electron microscope SEM; Figure 4 Test operation schematic diagram in test example. DETAILED DESCRIPTION
[0008] The application will be further described in detail below in combination with examples, comparative examples and test examples, but the protection scope of the application is not limited to these examples.
[0009] The Ti3C2T x / MoS2nanocomposite material-based special polyurea grease is made of 2~4wt% Ti3C2T x / MoS2nanocomposite powder, 96~98wt% polyurea grease base, and the total is 100%; the polyurea grease base is made of 79~87wt% base oil, 6~9wt% diisocyanate, 6~8wt% amine, 0.5~2wt% antioxidant, and 0.5~2wt% anti-wear agent, and the total of each raw material is 100%; wherein the base oil is compounded by poly-alpha-olefin (PAO) and synthetic ester at a weight ratio of 75~85:15~25, and the total is 100 parts, the synthetic ester is diisooctyl sebacate, dioctyl phthalate or neopentyl glycol dioctanoate; the amine is primary amine or secondary amine; and the preparation method is: A, preparation of Ti3C2T x / MoS2nanocomposite powder: A1, 1.5~2.5g Ti3AlC2powder is added to 15~25mL aqueous solution containing 0.5~1.5g LiF and 5.5~6.5M HCl, stirred at 34~36℃ for 23~25h; after the reaction is completed, the reaction solution is centrifuged and washed repeatedly with deionized water until pH=5.8~6.2, to obtain a solid-liquid weight ratio of 1:40~60 multilayer Ti3C2T x suspension; the multilayer Ti3C2T x suspension is treated by ultrasonic at a power of 300~500W for 28~32min, and then freeze-dried at-40~-60℃ for 24~36h to obtain fluffy Ti3C2T xpowder; A2, the fluffy Ti3C2T x The powder 0.15~0.25g is dispersed in 36~44mL deionized water and 0.4~0.6g ammonium tetrathiomolybdate is added, mixed to obtain mixture a; the mixture a is transferred to a reaction kettle and hydrothermal reaction is carried out at 200~220℃ for 11~13h, to obtain Ti3C2T x / MoS2 suspension; the Ti3C2T x / MoS2 suspension is centrifuged at a speed of 9000~11000rpm and washed with deionized water for 3~5 times, and then the solid part is freeze-dried at-40~-60℃ for 24~36h, to obtain Ti3C2T x / MoS2 nanocomposite powder; B, preparation of polyurea grease base: B1, according to the raw material ratio of the polyurea grease base, the base oil is placed in a stirring kettle and antioxidants and anti-wear agents are added, heated to 85~95℃ and stirred at a speed of 150~250rpm for 25~35min, fully dissolved and mixed to obtain mixture b; B2, under nitrogen protection, according to the raw material ratio of the polyurea grease base, the diisocyanate is slowly dropped into the mixture b, then the amine is added and the temperature is raised to 90~100℃, and the stirring speed is 150~250rpm, and the reaction is carried out for 1~2h, so that the mixed system becomes a uniform gel, then it is transferred to a high shear dispersion machine and stirred at a speed of 600~800rpm for 20~30min, to obtain mixture c; B3, the mixture c is heated to 115~125℃ and continuously stirred at a speed of 150~250rpm for 0.8~1.2h, and after the refining, the product is sent to a three-roll mill for grinding 2 or 3 times, and the speed ratio of the three rollers in the three-roll mill is 1:3:9, to obtain the polyurea grease base; C, according to the ratio of the special polyurea grease, the Ti3C2T x / MoS2 nanocomposite powder is added to the polyurea grease base and mixed, and then sent to a three-roll mill for grinding 2 or 3 times, and the speed ratio of the three rollers in the three-roll mill is 1:3:9, to obtain the special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0010] Further, the antioxidant is a diphenylamine antioxidant or a hindered phenolic antioxidant, and the anti-wear agent is a phosphate anti-wear agent.
[0011] Further, the diphenylamine antioxidant is diisopropyl diphenylamine, p-octyldiphenylamine or phenyl-alpha-naphthylamine, the hindered phenol antioxidant is 2,6-di-tert-butyl-p-cresol (BHT), 4,4'-methylenebis(2,6-di-tert-butylphenol) or tris(3,5-di-tert-butyl-4-hydroxyphenyl)propane, and the phosphate anti-wear agent is triphenyl phosphate, tris(2-ethylhexyl) phosphate or tri-nonylphenyl phosphate.
[0012] Further, the base oil is compounded by poly-alpha-olefin (PAO) and synthetic ester at a weight ratio of 80:20.
[0013] Further, in step A1, 2 g of Ti3AlC2 powder is added to 20 mL of an aqueous solution containing 1 g of LiF and 6 M HCl, and stirred at 35°C for 24 h; after the reaction is completed, the reaction solution is centrifuged and washed repeatedly with deionized water until the pH is 6, to obtain Ti3C2T x suspension; the Ti3C2T x suspension is ultrasonically treated at a power of 400 W for 30 min, and then freeze-dried at -40°C for 36 h to obtain fluffy dry Ti3C2T x powder.
[0014] Further, in step A2, 0.2 g of Ti3C2T x powder is dispersed in 40 mL of deionized water and 0.5 g of ammonium tetrathiomolybdate is added, and mixed to obtain a mixture a; the mixture a is transferred to a reaction kettle and hydrothermally reacted at 210°C for 12 h to obtain a Ti3C2T x / MoS2 suspension; the Ti3C2T x / MoS2 suspension is centrifuged at a speed of 10,000 rpm and washed with deionized water for 4 times, and then the solid part is freeze-dried at -40°C for 36 h to obtain Ti3C2T x / MoS2 nanocomposite powder.
[0015] Further, in step B1, according to the raw material ratio of the polyurea grease base, 83 wt% of the base oil is placed in a stirred kettle and 1.5 wt% of 2,6-di-tert-butyl-p-cresol and 1.5 wt% of triphenyl phosphate are added, heated to 90°C and stirred at a constant temperature of 200 rpm for 30 min, fully dissolved and mixed to obtain a mixture b; the base oil is compounded by poly-alpha-olefin and diisooctyl sebacate at a weight ratio of 80:20.
[0016] Further, in step B2, under nitrogen protection, the raw materials for the polyurea grease base were proportioned, 6wt% of diisocyanate was slowly added into the mixture b at a speed of 8 drops / min, 8wt% of primary amine was added, and the mixture was stirred at 95°C and 200 rpm for 1.5h, so that the mixed system became a uniform colloid, and then was transferred to a high-shear dispersion machine for stirring at 700 rpm for 25 min, to obtain mixture c.
[0017] Further, in step B3, the mixture c was heated to 120°C and continuously stirred at 200 rpm for 1h, and then the product was sent to a three-roll mill for grinding for 3 times, the rotation speed ratio of the three rollers in the three-roll mill was 1:3:9, to obtain the polyurea grease base.
[0018] Further, in step C, according to the proportioning of the special polyurea grease, 3wt% of Ti3C2T x / MoS2 nanocomposite powder was added into the polyurea grease base and uniformly mixed, and then was sent to a three-roll mill for grinding for 3 times, the rotation speed ratio of the three rollers in the three-roll mill was 1:3:9, to obtain the special polyurea grease based on Ti3C2T x / MoS2 nanocomposite.
[0019] Example 1 A, preparation of Ti3C2T x / MoS2 nanocomposite powder: A1, 2g of Ti3AlC2 powder was added into 20mL of aqueous solution containing 1g of LiF and 6M HCl, and was stirred at 35°C for 24h, so that the Al layer was fully etched and fell off to form layered Ti3C2T x ; after the reaction, the reaction solution was centrifuged and repeatedly washed with deionized water until pH=6, and in the process, the solution color changed from gray-black to dark black, indicating that the layered Ti3C2T x structure was formed, to obtain a multilayer Ti3C2T x suspension with a solid-liquid weight ratio of 1:50; the multilayer Ti3C2T x suspension was ultrasonically treated at a power of 400W for 30min, and in the process, the layered nanosheets were fully exfoliated, and then was freeze-dried at -40°C for 36h to obtain black fluffy dry Ti3C2T x powder; A2, 0.2g of Ti3C2T x powder was dispersed in 40mL of deionized water and 0.5g of (NH4)2MoS4 (ammonium tetrathiomolybdate) was added, and the mixture was uniformly mixed to obtain mixture a; the mixture a was transferred to a reaction kettle and hydrothermally reacted at 210°C for 12h to obtain Ti3C2T xThe color of the solution during the process deepened from black to dark black, indicating that the MoS2 nanosheets were successfully grown on the surface of Ti3C2T x The Ti3C2T x The Ti3C2T x / MoS2 nanocomposite powder was obtained. B, preparation of polyurea grease base: B1, according to the raw material ratio of polyurea grease base, 83wt% of base oil (poly-α-olefin PAO and diisooctyl sebacate were compounded in a weight ratio of 80:20) was placed in a stirred tank and 1.5wt% 2,6-di-tert-butyl-p-cresol (BHT) and 1.5wt% triphenyl phosphate were added, heated to 90℃ and stirred at 200rpm for 30min, fully dissolved and mixed to obtain mixture b; B2, under nitrogen protection, according to the raw material ratio of polyurea grease base, 6wt% of diisocyanate was slowly added into mixture b at a speed of 8 drops / min, 8wt% of primary amine was added and stirred at 200rpm for 1.5h at 95℃, during which the diisocyanate and amine completely reacted to form a polyurea thickening agent, and the mixed system gradually changed into a uniform gel; then it was transferred to a high shear dispersion machine and stirred at 700rpm for 25min to ensure that the polyurea thickening agent was fully dispersed, and mixture c was obtained; B3, mixture c was heated to 120℃ and continuously stirred at 200rpm for 1h, and the product was sent to a three-roll mill for grinding for 3 times, and the speed ratio of the three rollers in the three-roll mill was 1:3:9, to obtain a uniform and delicate polyurea grease base; C, according to the ratio of special polyurea grease, 3wt% of Ti3C2T x / MoS2 nanocomposite powder was added to the polyurea grease base and mixed uniformly, and then sent to a three-roll mill for grinding for 3 times, and the speed ratio of the three rollers in the three-roll mill was 1:3:9, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0020] Example 2 According to the ratio of special polyurea grease, 2wt% of Ti3C2T x / MoS2 nanocomposite powder was added to the polyurea grease base, and other operations were the same as in Example 1, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0021] Example 3 According to the proportion of the special polyurea grease, 4wt% of Ti3C2T x / MoS2 nanocomposite powder is added to the polyurea grease matrix, and the other is the same as in Example 1, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite.
[0022] Example 4 A, preparation of Ti3C2T x / MoS2 nanocomposite powder: A1, 1.5g of Ti3AlC2 powder is added to 15mL of aqueous solution containing 1.5g of LiF, 6.5M HCl, and stirred at 34℃ for 23h, so that the Al layer is fully etched and falls off to form layered Ti3C2T x ; After the reaction, the reaction solution is centrifuged and washed repeatedly with deionized water until the pH is 5.8, and the color of the solution changes from gray black to dark black during the process, indicating that the layered Ti3C2T x structure is formed, and a multilayer Ti3C2T x suspension with a solid-liquid weight ratio of 1:40 is obtained; the multilayer Ti3C2T x suspension is treated with ultrasonic waves at a power of 500W for 28min, and the layered nanosheets are fully exfoliated during the process, and then freeze-dried at-50℃ for 30h to obtain black fluffy dry Ti3C2T x powder; A2, 0.25g of Ti3C2T x powder is dispersed in 36mL of deionized water and 0.4g of (NH4)2MoS4 (ammonium tetrathiomolybdate) is added, and the mixture is mixed to obtain a mixture a; the mixture a is transferred to a reaction kettle and hydrothermally reacted at 200℃ for 13h to obtain a Ti3C2T x / MoS2 suspension, and the color of the solution changes from black to dark black during the process, indicating that MoS2 nanosheets are successfully grown on the surface of Ti3C2T x ; The Ti3C2T x / MoS2 suspension is centrifuged at a speed of 9000rpm and washed with deionized water for 5 times, and then the solid part is freeze-dried at-50℃ for 30h to obtain black Ti3C2T x / MoS2 nanocomposite powder; B, preparation of polyurea grease matrix: B1, according to the raw material ratio of the polyurea grease base, 79wt% of the base oil (poly-alpha-olefin PAO and dioctyl phthalate are compounded in a weight ratio of 75:25) is placed in a stirred tank and 2wt% of diisopropyl diphenylamine, 2wt% of tris (2-ethylhexyl) phosphate is added, heated to 85°C and stirred at 150rpm for 35min, fully dissolved and mixed to obtain mixture b; B2, under nitrogen protection, according to the raw material ratio of the polyurea grease base, 9wt% of diisocyanate is slowly dropped into mixture b at 8 drops / min, 8wt% of secondary amine is added and stirred at 150rpm for 2h at 90°C, during which the diisocyanate and amine are completely reacted to form a polyurea thickener, and the mixed system gradually becomes a uniform colloid; then it is transferred to a high shear dispersion machine and stirred at 600rpm for 30min to ensure that the polyurea thickener is fully dispersed, and mixture c is obtained; B3, mixture c is heated to 115°C and continuously stirred at 150rpm for 1.2h, and then the product is sent to a three-roll mill for grinding twice, with a speed ratio of 1:3:9 for the three rollers in the three-roll mill, to obtain a uniform and fine polyurea grease base; C, according to the ratio of the special polyurea grease, 3wt% of Ti3C2T x / MoS2 nanocomposite powder is added to the polyurea grease base and mixed uniformly, and then sent to a three-roll mill for grinding twice, with a speed ratio of 1:3:9 for the three rollers in the three-roll mill, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0023] Example 5 A, preparation of Ti3C2T x / MoS2 nanocomposite powder: A1, 2.5g of Ti3AlC2 powder is added to 25mL of aqueous solution containing 0.5g of LiF and 5.5M of HCl, stirred at 36°C for 25h to make the Al layer fully etched and fall off, forming layered Ti3C2T x ; after the reaction, the reaction solution is centrifuged and washed repeatedly with deionized water until the pH is 6.2, and the color of the solution changes from gray black to dark black, indicating that the layered Ti3C2T x structure is formed, and a multi-layer Ti3C2T x suspension is obtained with a solid-liquid weight ratio of 1:60; the multi-layer Ti3C2T x suspension is treated by ultrasonic at 300W power for 32min, during which the layered nanosheet is fully exfoliated, and then freeze-dried at-60°C for 24h to obtain black fluffy dry Ti3C2T x powder; A2, 0.15g of Ti3C2Tx The powder was dispersed in 44 mL of deionized water and 0.6 g of (NH4)2MoS4(ammonium tetrathiomolybdate) was added, and mixed to obtain mixture a; mixture a was transferred to a reaction kettle and hydrothermal reaction was carried out at 220°C for 11 h to obtain a Ti3C2T x / MoS2 suspension, and the solution color was darkened from black to ink black during the process, indicating that MoS2nanosheets were successfully grown on the surface of Ti3C2T x ; the Ti3C2T x / MoS2 suspension was centrifuged at a speed of 11000 rpm and washed with deionized water for 3 times, and then the solid part was freeze-dried at -60°C for 24 h to obtain black Ti3C2T x / MoS2 nanocomposite powder; B, preparation of a polyurea grease base: B1, according to the raw material ratio of the polyurea grease base, 87wt% of the base oil (poly-alpha-olefin PAO and neopentyl glycol dioctanoate were compounded in a weight ratio of 85:15) was placed in a stirred kettle and 0.5wt% of tris(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 0.5wt% of trisnonylphenyl phosphate was added, heated to 95°C and stirred at a constant temperature of 250 rpm for 25 min, fully dissolved and mixed to obtain mixture b; B2, under nitrogen protection, according to the raw material ratio of the polyurea grease base, 6wt% of diisocyanate was slowly added to mixture b at a rate of 8 drops / min, 6wt% of primary amine was added and stirred at 250 rpm at 100°C for 1 h, during which the diisocyanate and amine completely reacted to form a polyurea thickening agent, and the mixed system gradually changed into a uniform gel; then it was transferred to a high shear dispersion machine and stirred at 800 rpm for 20 min to ensure that the polyurea thickening agent was fully dispersed, to obtain mixture c; B3, mixture c was heated to 125°C and continuously stirred at 250 rpm for 0.8 h, and then the product was fed into a three-roll mill and milled for 3 times, the speed ratio of the three rolls in the three-roll mill was 1:3:9, to obtain a uniform and delicate polyurea grease base; C, according to the ratio of the special polyurea grease, 3wt% of Ti3C2T x / MoS2 nanocomposite powder was added to the polyurea grease base and mixed, and then fed into a three-roll mill and milled for 3 times, the speed ratio of the three rolls in the three-roll mill was 1:3:9, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite material.
[0024] Comparative Example 1 According to the ratio of the special polyurea grease, step C, 1wt% of Ti3C2T x / MoS2nanocomposite powder is added into the polyurea grease base, and other steps are the same as those in Example 1 to obtain polyurea grease A.
[0025] Comparative Example 2 According to the ratio of the special polyurea grease, 5wt% of Ti3C2T x / MoS2nanocomposite powder is added into the polyurea grease base, and other steps are the same as those in Example 1 to obtain polyurea grease B.
[0026] Comparative Example 3 The polyurea grease base obtained in step B of Example 1 is polyurea grease C, and other steps of Example 1 are omitted.
[0027] Comparative Example 4 Based on Example 1, steps A1 and A2 are omitted, and the polyurea grease base is prepared according to step B; according to step C of Example 1, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% of MoS2nanopowder replace Ti3C2T x / MoS2nanocomposite powder is added into the polyurea grease base, and other steps are the same as those in Example 1 to obtain polyurea grease B.
[0028] Comparative Example 5 Based on Example 1, step A2 is omitted, and fluffy dry Ti3C2T x powder and polyurea grease base are prepared according to steps A1 and B, respectively; according to step C of Example 1, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% of fluffy dry Ti3C2T x powder replace Ti3C2T x / MoS2nanocomposite powder is added into the polyurea grease base, and other steps are the same as those in Example 1 to obtain polyurea grease B.
[0029] Comparative Example 6 Based on Example 1, step A2 is omitted, and fluffy dry Ti3C2T x powder and polyurea grease base are prepared according to steps A1 and B, respectively; according to step C of Example 1, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% of MoS2nanopowder / Ti3C2T x powder mixture (mass ratio 3:2) replace Ti3C2T x / MoS2nanocomposite powder is added into the polyurea grease base, and other steps are the same as those in Example 1 to obtain polyurea grease B.
[0030] Test Example Based on Ti3C2T xThe special polyurea grease of / MoS2 nanocomposite (hereinafter referred to as special polyurea grease) and the polyurea grease prepared in Comparative Examples 1-6 were used as test objects and subjected to the following tests. The four-ball friction and wear tester was used for testing under the conditions of a load of 392 N, a rotation speed of 1200 rpm, and a temperature of 300°C, and the test was continued for 60 min. The friction coefficient, wear scar diameter, and oil exudation rate of each test object were recorded.
[0031] Test results: I. The special polyurea grease prepared in Examples 1-5 (2-4 wt% of Ti3C2T x / MoS2 nanocomposite powder, hereinafter referred to as powder A) and the polyurea grease prepared in Comparative Examples 1-3 (1 wt%, 5 wt%, and 0 wt% of powder A, respectively) were subjected to tests, and the results are shown in Table 1.
[0032] Table 1. Test results of polyurea grease based on different amounts of powder A
[0033] Results analysis: Compared with the polyurea grease C of Comparative Example 3, the special polyurea grease prepared in Examples 1-5 had a friction coefficient of 0.057-0.071, a wear scar diameter of 0.37-0.45 mm, and an oil exudation rate of 2.1-2.4 wt% at 300°C (392 N, 1200 rpm).
[0034] In Example 1, the amount of powder A was 3 wt%, and the data of the friction coefficient, wear scar diameter, and oil exudation rate were the lowest, which were better than those of Examples 2 and 3 in which the amounts of powder A were 2 wt% and 4 wt%, respectively. In Comparative Examples 1 and 2, the amounts of powder A in the polyurea greases A and B were adjusted to 1 wt% and 5 wt%, respectively, and the friction coefficient, wear scar diameter, and oil exudation rate were significantly worse than those of Examples 1-3. Obviously, when the amount of powder A was 2-4 wt% in the same polyurea grease matrix, the special polyurea grease had better lubricating effect, wear resistance, and grease stability. This indicates that when Ti3C2T x / MoS2 is used in the form of powder A, Ti3C2T x can provide sufficient thermal conductivity and mechanical support, and the in-situ grown MoS2 forms a more reliable easy-slipping layer, and the two together form a more ideal interface synergistic friction reduction and wear resistance effect. At the same time, selecting an appropriate amount of powder A (2-4 wt%) can achieve better results. When the amount of powder A is too low, it cannot provide sufficient lubrication, wear resistance, and grease stability, and when the amount of powder A is too high, the nanoparticles may agglomerate, which will result in a decrease in the lubricating effect, wear resistance, and grease stability at high temperatures.
[0035] From the application effect of examples 4, 5, even if the powder A addition amount is 3wt%, due to the change of the preparation conditions of the polyurea grease base, the friction coefficient, the wear scar diameter, and the oil release rate are not as good as example 1, however, due to the powder A addition amount of 3wt%, the test parameters are still close to examples 2, 3; it is shown that the preparation method of the powder A and the polyurea grease base will affect the application effect to some extent, that is, the application effect of the special polyurea grease prepared according to example 1 and with 3wt% powder A is the best.
[0036] II, the test results of polyurea greases D1, D2, D3, D4, D5 prepared in comparative example 4 are shown in table 2.
[0037] Table 2 Test effect of polyurea grease based on different MoS2 addition amount
[0038] Result analysis: Comparative example 4 selects the same polyurea grease base as example 1, and 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% MoS2 nano powder is added into the base respectively; table 2 shows that although the polyurea greases D1~D5 are improved compared with polyurea grease C, they are still significantly inferior to examples 1~5 and comparative examples 1, 2 in terms of friction coefficient, wear scar diameter, and oil release rate.
[0039] III, the test results of polyurea greases E1, E2, E3, E4, E5 prepared in comparative example 5 are shown in table 3.
[0040] Table 3 Test effect of polyurea grease based on different Ti3C2T x addition amount
[0041] Result analysis: Comparative example 5 also selects the same polyurea grease base as example 1, and the fluffy dry Ti3C2T x powder prepared in step A1 of example 1 is added into the base at 1wt%, 2wt%, 3wt%, 4wt%, and 5wt% respectively; table 3 shows that although the polyurea greases E1~E5 are improved compared with polyurea grease C, they are still significantly inferior to examples 1~5 and comparative examples 1, 2 in terms of friction coefficient, wear scar diameter, and oil release rate; from the data in tables 2, 3, it is not difficult to find that MoS2 nano powder is more beneficial to improving the lubricating performance and the stability of polyurea grease than Ti3C2T x powder at the same addition amount.
[0042] IV, the test results of polyurea greases F1, F2, F3, F4, F5 prepared in comparative example 6 are shown in table 4.
[0043] Table 4 Lubricating effect of polyurea grease with different MoS2 nanopowder / Ti3C2T x Test effect of polyurea grease with different powder mixture addition amount
[0044] Result analysis: Comparative example 6 also selected the same polyurea grease matrix as example 1, and the fluffy dry Ti3C2T x powder prepared in step A1 of example 1 was mixed with MoS2 nanopowder at a mass ratio of 3:2 (the ratio is close to the proportion of Ti3C2T x and MoS2 in powder A obtained in example 1), and the mixture was added to the matrix at 1wt%, 2wt%, 3wt%, 4wt%, and 5wt%, respectively; Table 4 shows that, in terms of friction coefficient, wear scar diameter, and oil exudation rate, although F1~F5 are improved compared with the single addition of MoS2 nanopowder and Ti3C2T x powder in comparative examples 4 and 5, there is still a significant gap with examples 1~5, especially in terms of lubricating performance and polyurea grease stability; that is, the Ti3C2T x powder prepared in example 1 and the MoS2 nanopowder cannot achieve the effects of examples 1~5 in lubrication, wear resistance, and stability after being mixed and added to the same matrix.
[0045] Therefore, compared with the single addition of MoS2, Ti3C2T x or the conventional mixing and addition of MoS2 and Ti3C2T x , the present application realizes the in-situ growth of MoS2 on Ti3C2T x by the preparation method, and the powder A and the suitable polyurea grease matrix are compounded at a suitable ratio, which not only fully utilizes the known properties of MoS2 and Ti3C2T x , but also achieves a friction coefficient, wear scar diameter, and oil exudation rate far superior to the prior art; especially when the powder A is added at 3wt%, the friction coefficient, wear scar diameter, and oil exudation rate of the special polyurea grease obtained at 300℃ (392N, 1200rpm) can be as low as 0.057, 0.37mm, and 2.1wt%, respectively, and when added at other amounts, the friction coefficient, wear scar diameter, and oil exudation rate are not more than 0.071, 0.45mm, and 2.4wt%, respectively; it can be predicted that the special polyurea grease prepared by the present application can provide an ideal friction coefficient in a high temperature environment of 250~320℃, and the wear scar diameter and oil exudation rate can also be controlled within a reasonable range.
Claims
1. A special polyurea grease based on Ti3C2T x / MoS2 nanocomposite, characterized by that, The special polyurea grease is made of Ti3C2T x / MoS2 nanocomposite powder 2~4wt%, polyurea grease base 96~98wt%, total 100%; the polyurea grease base is made of base oil 79~87wt%, diisocyanate 6~9wt%, amine 6~8wt%, antioxidant 0.5~2wt%, anti-wear agent 0.5~2wt%, and the total of each raw material is 100%; wherein the base oil is compounded by poly-alpha-olefin and synthetic ester according to the weight ratio of 75~85:15~25, total 100 parts, and the synthetic ester is diisooctyl sebacate, dioctyl phthalate or neopentyl glycol dioctanoate; the amine is primary amine or secondary amine; the preparation method is: A. Preparation of Ti3C2T x / MoS2 nanocomposite powder: A1, 1.5-2.5 g Ti3AlC2 powder is added into 15-25 mL aqueous solution containing 0.5-1.5 g LiF, 5.5-6.5 M HCl, and stirred at 34-36 °C for 23-25 h; after the reaction is completed, the reaction solution is centrifuged and repeatedly washed with deionized water until pH = 5.8-6.2, to obtain a multi-layer Ti3C2T x suspension; the multi-layer Ti3C2T x suspension is ultrasonically treated at 300-500 W power for 28-32 min, and then freeze-dried at -40--60 °C for 24-36 h to obtain fluffy Ti3C2T x powder; A2, Ti3C2T x powder 0.15~0.25g was dispersed in 36~44mL deionized water and 0.4~0.6g ammonium tetrathiomolybdate was added, mixed to obtain mixture a; mixture a was transferred to a reaction kettle and hydrothermal reaction was carried out at 200~220℃ for 11~13h to obtain Ti3C2T x / MoS2 suspension; Ti3C2T x / MoS2 suspension was centrifuged at 9000~11000rpm and washed with deionized water for 3~5 times, then the solid part was freeze-dried at-40~-60℃ for 24~36h to obtain Ti3C2T x / MoS2 nanocomposite powder; B. Preparation of polyurea grease base: B1. According to the raw material ratio of the polyurea grease base, the base oil is placed in the stirred kettle and the antioxidant and the anti-wear agent are added, heated to 85-95℃ and stirred at a constant temperature of 150-250 rpm for 25-35 min, fully dissolved and mixed to obtain a mixture b; B2. Under nitrogen protection, according to the raw material ratio of the polyurea grease base, the diisocyanate is slowly dropped into the mixture b, then the amine is added and heated to 90-100℃ and stirred at a speed of 150-250 rpm for 1-2 h, so that the mixed system becomes a uniform colloid, then it is transferred to a high-shear disperser and stirred at a speed of 600-800 rpm for 20-30 min to obtain a mixture c; B3. The mixture c is heated to 115-125℃ and continuously stirred at a speed of 150-250 rpm for 0.8-1.2 h, and then the product is sent to a three-roll mill for grinding for 2 or 3 times, and the speed ratio of the three rollers in the three-roll mill is 1:3:9 to obtain the polyurea grease base; C, according to the proportion of special polyurea grease, Ti3C2T x / MoS2 nanocomposite powder is added to the polyurea grease matrix and mixed uniformly, and then sent to a three-roll grinding machine for grinding 2 or 3 times. The rotation speed ratio of the three rollers in the three-roll grinding machine is 1:3:9, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite.
2. The special polyurea grease according to claim 1, characterized in that, The antioxidant is a diphenylamine antioxidant or a hindered phenol antioxidant, and the anti-wear agent is a phosphate ester anti-wear agent.
3. The special polyurea grease according to claim 2, characterized in that, The diphenylamine antioxidant is diisopropyl diphenylamine, p-octyl diphenylamine or phenyl-α-naphthylamine, the hindered phenol antioxidant is 2,6-di-tert-butyl-p-cresol, 4,4'-methylene bis(2,6-di-tert-butyl phenol) or tris(3,5-di-tert-butyl-4-hydroxyphenyl) propane, and the phosphate ester anti-wear agent is triphenyl phosphate, tris(2-ethylhexyl) phosphate or tris(nonylphenyl) phosphate.
4. The special polyurea grease according to claim 1, characterized in that, The base oil is compounded by 80 parts of poly-alpha-olefin and 20 parts of synthetic ester by weight.
5. The special polyurea grease according to claim 1, characterized in that, In step A1, 2 g of Ti3AlC2 powder was added into 20 mL of aqueous solution containing 1 g of LiF, 6 M HC1, and stirred at 35 °C for 24 h; after the reaction was completed, the reaction solution was centrifuged and washed repeatedly with deionized water until pH = 6, to obtain Ti3C2T x suspension with a solid-liquid weight ratio of 1 :
50. x The Ti3C2T x suspension was ultrasonically treated at a power of 400 W for 30 min, and then freeze-dried at -40 °C for 36 h to obtain fluffy dry Ti3C2T x powder.
6. The special polyurea grease according to claim 1, characterized in that, In step A2, 0.2 g Ti3C2T x The powder was dispersed in 40 mL deionized water and 0.5 g ammonium tetrathiomolybdate was added, mixed to obtain mixture a; mixture a was transferred to a reaction kettle and hydrothermal reaction was carried out at 210°C for 12 h to obtain Ti3C2T x / MoS2 suspension; the Ti3C2T x / MoS2 suspension was centrifuged at a speed of 10000 rpm and washed with deionized water for 4 times, then the solid part was freeze-dried at -40°C for 36 h to obtain Ti3C2T x / MoS2 nanocomposite powder.
7. The special polyurea grease according to claim 1, characterized in that, In step B1, according to the raw material ratio of the polyurea grease base, 83wt% of the base oil is placed in the stirred kettle and 1.5wt% of 2,6-di-tert-butyl-p-cresol and 1.5wt% of triphenyl phosphate are added, heated to 90℃ and stirred at a constant temperature of 200 rpm for 30 min, fully dissolved and mixed to obtain a mixture b; the base oil is compounded by 80 parts of poly-alpha-olefin and 20 parts of diisooctyl sebacate by weight.
8. The special polyurea grease according to claim 1, characterized in that, In step B2, under nitrogen protection, according to the raw material ratio of the polyurea grease base, 6wt% of diisocyanate is slowly dropped into the mixture b at a speed of 8 drops / min, 8wt% of primary amine is added and stirred at 95℃ at a speed of 200 rpm for 1.5 h, so that the mixed system becomes a uniform colloid, then it is transferred to a high-shear disperser and stirred at a speed of 700 rpm for 25 min to obtain a mixture c.
9. The special polyurea grease according to claim 1, characterized in that, In step B3, the mixture c is heated to 120℃ and continuously stirred at a speed of 200 rpm for 1 h, and then the product is sent to a three-roll mill for grinding for 3 times, and the speed ratio of the three rollers in the three-roll mill is 1:3:9 to obtain the polyurea grease base.
10. The special polyurea grease according to claim 1, characterized in that, In step C, 3wt% of Ti3C2T x / MoS2 nanocomposite powder is added to the polyurea grease base and mixed uniformly, and then sent to a three-roll grinding machine for grinding three times. The rotation speed ratio of the three rollers in the three-roll grinding machine is 1:3:9, to obtain a special polyurea grease based on Ti3C2T x / MoS2 nanocomposite.