PAMA type multifunctional lubricating additive based on carboxyl-biquaternary ammonium salt interaction, preparation method and application of PAMA type multifunctional lubricating additive and lubricant

Abstract

The invention provides a PAMA type multifunctional lubricating additive based on carboxyl-biquaternary ammonium salt interaction, a preparation method and application of the PAMA type multifunctional lubricating additive and a lubricant, and belongs to the technical field of lubricating materials. The carboxyl is introduced, so that the adsorption of a polymer on an interface can be enhanced, the lubricating effect is improved, meanwhile, crosslinking sites are provided, the performance of the lubricating additive is further improved, the lubricating additive has excellent antifriction and antiwear performance, and the problem that the friction performance is reduced due to insufficient adsorption of PAMA polymers on a metal substrate due to crosslinking of the carboxyl is solved. The PLA-HODMDAB can realize function integration of a viscosity index improver and an antifriction and antiwear additive, the introduction of carboxyl not only can enhance interfacial adsorption and improve friction, but also can be used as a crosslinking site to further enhance tackifying and viscosity-temperature performance through crosslinking, so that the PLA-HODMDAB has excellent viscosity-temperature performance and lubricating performance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and in particular to a PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt, a preparation method and application thereof, and a lubricant. Background Art

[0002] Friction and wear cause numerous mechanical failures and energy losses, shortening equipment lifespan and leading to significant economic losses and energy waste. Therefore, effective friction and wear reduction not only improves energy efficiency and conserves energy, but also reduces and prevents component failures, thereby extending the service life of mechanical systems and significantly reducing production and maintenance costs. The rational use of lubricants is the primary method for friction and wear reduction. Lubricating oils are widely used, and a large number of lubricant additives have been developed. However, with the continuous emergence of various high-precision machinery and equipment and the rapid development of the machinery industry, single lubricant additives are no longer sufficient. Harsh operating conditions and complex friction environments place greater demands on the diversification of lubricant additive functionality. While the combination of multiple additives has some success in improving lubricant performance, the matching and interactions of different additives in practical applications present numerous challenges, such as developing a scientifically formulated formula and investigating the compatibility of different additives. Therefore, the design and preparation of novel multifunctional lubricant additives offers a viable approach to addressing these challenges and holds enormous potential for application and research.

[0003] Polymethacrylate (PAMA)-based polymers, as classic viscosity index improvers (VII), can effectively improve the kinematic viscosity and viscosity-temperature properties of lubricating oils. However, their anti-friction and anti-wear properties are relatively weak, and lubrication failure may occur under boundary lubrication. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt, as well as its preparation method, application, and lubricant. The PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt provided by the present invention has excellent friction reducing and anti-wear properties.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a PAMA-type multifunctional lubricating additive (PLA-HODMDAB) based on the interaction between carboxyl and diquaternary ammonium salt, having a structure shown in Formula I:

[0007]

[0008] In formula I, m:n is 1:9-11.

[0009] Preferably, the m:n is 1:10.

[0010] The present invention also provides a method for preparing the PAMA-type multifunctional lubricating additive described in the above technical solution, comprising the following steps:

[0011] Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to perform a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer (P(LMA-AA), abbreviated as PLA);

[0012] The poly(lauryl methacrylate-acrylic acid) random copolymer, N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide, an organic solvent and an alkaline solution are mixed and reacted to obtain the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt;

[0013] The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II:

[0014]

[0015] In formula II, m:n is 1:9-11.

[0016] Preferably, the molar ratio of acrylic acid to lauryl methacrylate is 1:9-11.

[0017] Preferably, the temperature of the free radical polymerization reaction is 75-90° C., and the time is 7-10 hours.

[0018] Preferably, the mass ratio of the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide to the poly(lauryl methacrylate-acrylic acid) random copolymer is 1:205-210.

[0019] Preferably, the alkaline solution comprises a NaOH solution, and the mass ratio of NaOH to poly(lauryl methacrylate-acrylic acid) random copolymer in the NaOH solution is 1:25000.

[0020] The present invention also provides the use of the PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt described in the above technical solution in the field of mechanical parts lubrication.

[0021] The present invention also provides a lubricant comprising a base oil and an additive, wherein the additive is the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt as described in the above technical solution.

[0022] Preferably, the lubricant comprises the following components in mass percentage: 95% to 99% base oil and 1% to 5% additive.

[0023] The present invention provides a PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt. Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention not only enhances the adsorption of the polymer at the interface and improves the lubrication effect by introducing a carboxyl group into a traditional PAMA-based polymer, but also provides a cross-linking site (diquaternary ammonium salt group), further improving the performance of the lubricating additive, making it have excellent friction-reducing and anti-wear properties, avoiding the problem of reduced friction performance caused by insufficient adsorption of the PAMA-based polymer on the metal substrate due to the cross-linking of the carboxyl group, and making up for the problem of insufficient friction performance of the PAMA-based polymer. In addition, the PLA-HODMDAB of the present invention can realize the functional integration of a viscosity index improver and a friction-reducing and anti-wear additive. The introduction of the carboxyl group can not only enhance interfacial adsorption and improve friction, but also further enhance viscosity and viscosity-temperature properties through cross-linking as a cross-linking site, so that it has excellent viscosity-temperature properties and lubrication properties at the same time, avoiding the limitation that traditional additives have a single function and need to be compounded, while reducing the cost of the additive. The PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt provided by the present invention can significantly increase the kinematic viscosity of base oil, and at the same time has excellent viscosity-temperature performance and friction reduction and anti-wear performance, and can simultaneously meet the requirements of a viscosity index improver and a friction reduction and anti-wear additive. It has broad application prospects in the fields of automobiles, ships, industrial equipment, mechanical parts lubrication, etc.

[0025] The data of the examples show that compared with the commercial viscosity index agent 8-310, the carboxyl-diquaternary ammonium salt-interactive PAMA-type multifunctional lubricating additive PLA+AIP of the present invention exhibits better viscosity-temperature performance and friction performance.

[0026] The present invention also provides a method for preparing a PAMA-type multifunctional lubricating additive based on the carboxyl-diquaternary ammonium salt interaction described in the above technical solution. PAMA is selected as a carrier, and the carboxyl functionalization of PAMA is achieved through a free radical polymerization reaction of acrylic acid and lauryl methacrylate. At the same time, a diquaternary ammonium salt ionic liquid N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide is used as a crosslinking agent to cause a crosslinking reaction and an ion exchange reaction. While the performance of the additive is improved through the carboxyl-diquaternary ammonium salt interaction, the crosslinking agent itself also has a certain friction-reducing and anti-wear effect, further improving the application performance of the additive.

[0027] The present invention also provides the application of the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt in the field of mechanical parts lubrication. The PAMA-type multifunctional lubricating additive has a simple structure and is easy to synthesize, and has broad application prospects in the field of lubricating additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the H NMR spectrum of HODMDAB;

[0029] Figure 2 is the H NMR spectrum of PLA-HODMDAB;

[0030] Figure 3 The friction test results of 500SN, A1, A2 and A3 are shown below;

[0031] Figure 4 Friction test results for 500SN, A2, B2, and C2. DETAILED DESCRIPTION

[0032] The present invention provides a PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt, having a structure shown in Formula I:

[0033]

[0034] In formula I, m:n is 1:9-11, preferably 1:10.

[0035] The PAMA-type multifunctional lubricating additive PLA-HODMDAB based on the interaction between carboxyl and diquaternary ammonium salt can realize the integration of the functions of a viscosity index improver and a friction reducing and anti-wear additive. The introduction of carboxyl groups can not only enhance interfacial adsorption and improve friction, but also serve as cross-linking sites to further enhance viscosity-increasing and viscosity-temperature properties through cross-linking, thereby achieving both excellent viscosity-temperature properties and lubrication properties. This avoids the limitation of traditional additives that have a single function and need to be compounded, while also reducing the cost of the additives.

[0036] The present invention also provides a method for preparing the PAMA-type multifunctional lubricating additive based on the carboxyl-diquaternary ammonium salt interaction described in the above technical solution, comprising the following steps:

[0037] Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer;

[0038] The poly(lauryl methacrylate-acrylic acid) random copolymer, N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide, an organic solvent and an alkaline solution are mixed and reacted to obtain the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt;

[0039] The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II:

[0040]

[0041] In formula II, m:n is 1:9-11.

[0042] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0043] The present invention mixes acrylic acid, lauryl methacrylate, an organic solvent and an initiator to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer. The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II, where m:n in Formula II is preferably 1:10.

[0044] In the present invention, the molar ratio of acrylic acid to lauryl methacrylate is preferably 1:9-11, specifically 1:9, 1:10 or 1:11.

[0045] In the present invention, the organic solvent in the free radical polymerization reaction is preferably ethyl acetate, and the mass of the organic solvent is preferably 1.3 to 1.9 times the total mass of the reactants, specifically 1.3, 1.4, 1.5, 1.6, 1.7, 1.8 or 1.9 times. The reactants include acrylic acid and lauryl methacrylate.

[0046] In the present invention, the initiator preferably includes an azo initiator, more preferably includes azobisisobutyronitrile (AIBN), and the mass of the azo initiator preferably accounts for 0.5% to 1.5% of the total mass of the reactants, specifically 0.5%, 1% or 1.5%. The reactants include acrylic acid and lauryl methacrylate.

[0047] In the present invention, the temperature of the free radical polymerization reaction is preferably 75-90°C, specifically 75, 80, 85 or 90°C, and the time is preferably 7-10h, specifically 7, 8, 9 or 10h. The free radical polymerization reaction is preferably carried out under heating conditions.

[0048] Before the free radical polymerization reaction begins, nitrogen is preferably passed through for 15 minutes to expel air.

[0049] After the free radical polymerization reaction is completed, the product is preferably precipitated with anhydrous ethanol and then washed repeatedly 5 to 7 times until the upper liquid is clear to remove unreacted monomers to obtain the poly(lauryl methacrylate-acrylic acid) random copolymer.

[0050] After obtaining the poly(lauryl methacrylate-acrylic acid) random copolymer, the present invention mixes the poly(lauryl methacrylate-acrylic acid) random copolymer, N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide, an organic solvent and an alkaline solution for reaction to obtain the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt.

[0051] In the present invention, the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide has a structure shown in Formula III:

[0052]

[0053] In the present invention, the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide is preferably prepared by a method comprising the following steps:

[0054] 1,10-dibromodecane, trioctylamine and an organic solvent are mixed to carry out a nucleophilic substitution reaction to obtain the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide.

[0055] In the present invention, the molar ratio of the 1,10-dibromodecane to trioctylamine is preferably 1:2 to 2.3, specifically 1:2, 1:2.1, 1:2.2 or 1:2.3.

[0056] In the present invention, the organic solvent is preferably ethanol, and the mass of the organic solvent is preferably 1.5 to 1.9 times the total mass of the reactants, specifically 1.5, 1.8 or 1.9 times. The reactants include 1,10-dibromodecane and trioctylamine.

[0057] In the present invention, the temperature of the nucleophilic substitution reaction is preferably 65-80°C, specifically 65, 70, 75 or 80°C, and the time is preferably 23-26 hours, specifically 23, 24 or 26 hours.

[0058] In the present invention, the trioctylamine is preferably first added to the organic solvent, and then the 1,10-dibromodecane is added and mixed uniformly.

[0059] After the nucleophilic substitution reaction is completed, the product is preferably precipitated, washed and dried in sequence to obtain the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide.

[0060] In the present invention, the mass ratio of the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide to the poly(lauryl methacrylate-acrylic acid) random copolymer is preferably 1:205-210, specifically 1:205, 1:206, 1:207, 1:208, 1:209 or 1:210.

[0061] In the present invention, the poly(lauryl methacrylate-acrylic acid) random copolymer and N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide undergo crosslinking reaction and ion exchange reaction to obtain the PAMA-type multifunctional lubricating additive.

[0062] In the present invention, the alkaline solution preferably includes a NaOH solution, and the mass ratio of NaOH to poly(lauryl methacrylate-acrylic acid) random copolymer in the NaOH solution is preferably 1:25000.

[0063] In the present invention, the organic solvent of the reaction preferably includes dichloromethane, and the mass of the dichloromethane is preferably 6.5 to 7 times the total mass of the reactants, and the reactants include poly(lauryl methacrylate-acrylic acid) random copolymer and N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide.

[0064] In the present invention, the reaction temperature is preferably 20-30°C, specifically 20, 25 or 30°C, and the reaction time is preferably 11-14 hours, specifically 11, 12, 13 or 14 hours.

[0065] In the present invention, the poly(lauryl methacrylate-acrylic acid) random copolymer is preferably dissolved in an organic solvent, and then the HODMDAB and NaOH solution are added, and the reaction is carried out under heating and stirring.

[0066] After the reaction is completed, the product is preferably subjected to sequential precipitation, washing, drying, filtration, reduced pressure distillation and vacuum drying to obtain the PLA-HODMDAB.

[0067] The present invention also provides the use of the PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt described in the above technical solution in the field of mechanical parts lubrication.

[0068] The present invention also provides a lubricant comprising a base oil and an additive, wherein the additive is the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt as described in the above technical solution.

[0069] In the present invention, the lubricant preferably includes the following components in mass percentage: 95% to 99% of base oil, specifically 95%, 96%, 97%, 98% or 99%, and 1% to 5% of additives, specifically 1%, 2%, 3%, 4% or 5%.

[0070] In the present invention, the base oil preferably includes 500SN and / or PAO10.

[0071] The present invention also provides a method for preparing the lubricant, comprising the following steps: filtering the product obtained from the ion exchange reaction to obtain the lubricant.

[0072] The present invention also provides the use of the lubricant described in the above technical solution in the field of lubrication of mechanical parts, more preferably including the use in the fields of lubrication of automobiles, aircraft, ships or industrial parts.

[0073] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0074] Example 1

[0075] Preparation of a PAMA-type multifunctional lubricating additive based on carboxyl-diquaternary ammonium salt interaction comprises the following steps:

[0076] Dissolve trioctylamine (0.021 mol) in 20 mL of ethanol, then add 1,10-dibromodecane (0.01 mol) and stir to mix thoroughly. A nitrogen atmosphere was introduced for 15 minutes before the reaction to expel air. The temperature was then raised to 70°C and the reaction was refluxed for 24 hours. After the reaction, the reaction solution was cooled to room temperature, and the product was precipitated with methyl tert-butyl ether and washed three times with petroleum ether to remove any residual reactants, yielding N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide.

[0077] Acrylic acid (0.02 mol) and lauryl methacrylate (0.2 mol) were added to 87 mL of ethyl acetate and stirred to dissolve. Nitrogen was purged for 15 minutes before the reaction began. After the temperature was raised to 80°C, azobisisobutyronitrile (AIBN) (0.5232 g) was added and free radical polymerization was carried out at 80°C with stirring at 300 rpm for 10 hours, until the solution turned yellow and a significant viscosity change occurred. After the reaction, the product was precipitated with anhydrous ethanol and washed seven times until the supernatant was clear to remove unreacted monomers. This yielded poly(lauryl methacrylate-acrylic acid) random copolymer (P(LMA-AA)). PLA has the structure shown in Formula II, where m:n is 1:10.

[0078] 10g of PLA was dissolved in 50mL of dichloromethane, and the obtained HODMDAB (0.000048mol, 0.0484g) was added and sonicated to completely dissolve. 10mL of NaOH solution (0.001mol / L) was added to the reaction solution, and the reaction was stirred at 25°C for 12 hours. After the reaction, the solution was allowed to stand and separate into layers. The organic phase was washed three times with NaOH solution (0.001mol / L), dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by vacuum distillation. The resulting PAMA-type multifunctional lubricant additive, based on the carboxyl-bisquaternary ammonium salt interaction, had the structure shown in Formula I, where m:n is 1:10.

[0079] Figure 1 is the H NMR spectrum of HODMDAB, Figure 2 : is the nuclear magnetic resonance hydrogen spectrum of PLA-HODMDAB, which shows that the present invention prepared PLA-HODMDAB having the structure shown in Formula I.

[0080] 0.1 g of PLA-HODMDAB was added to 9.9 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, which was designated as A1.

[0081] 0.3 g of PLA-HODMDAB was added to 9.7 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, which was designated as A2.

[0082] 0.5 g of PLA-HODMDAB was added to 9.5 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, which was designated as A3.

[0083] Comparative Example 1

[0084] 0.1 g of PLA was added to 9.9 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B1, in which the PLA content was 1 wt%.

[0085] 0.3 g of PLA was added to 9.7 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B2, in which the PLA content was 3 wt%.

[0086] 0.5 g of PLA was added to 9.5 g of 500SN, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B3, in which the PLA content was 5 wt%.

[0087] Comparative Example 2

[0088] 0.1 g of commercial viscosity modifier 8-310 was added to 9.9 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C1, in which the content of 8-310 was 1 wt%.

[0089] 0.3 g of commercial viscosity modifier 8-310 was added to 9.7 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C2, in which the 8-310 content was 3 wt%.

[0090] 0.5 g of commercial viscosity modifier 8-310 was added to 9.5 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C3, in which the content of 8-310 was 5 wt%.

[0091] Performance testing:

[0092] 1. Viscosity increase and viscosity-temperature performance test

[0093] Using YP1003-III viscometer and Pinnacl viscometer ( The viscosity-increasing performance of a PAMA-type multifunctional lubricating additive based on the carboxyl-diquaternary ammonium salt interaction was evaluated using a constant of 1.145. The kinematic viscosities of the samples at 40°C and 100°C were measured, and the corresponding viscosity index was calculated based on the kinematic viscosities at 40°C and 100°C. The viscosity index was compared with that of 500SN, PAO10, PLA, and a commercial viscosity index agent 8-310.

[0094] Table 1 shows the kinematic viscosity and viscosity index test results for various samples. It can be seen that at only 1 wt% additive, 500SN with PLA-HODMDAB significantly improved both kinematic viscosity and viscosity index compared to neat 500SN, with significantly better improvements than the other two. The advantages of PLA-HODMDAB became increasingly pronounced with increasing concentration. At 3 wt% PLA-HODMDAB, the viscosity index reached 140, a 35.90% improvement compared to neat 500SN. When the PLA-HODMDAB content was increased to 5 wt%, the viscosity index rose to 161, a 56.31% increase. Meanwhile, the viscosity index of the 8-310 oil sample with a 3 wt% PLA addition was only 117, while at 5 wt% addition, the viscosity index rose to 128. This demonstrates that PLA-HODMDAB, cross-linked with a diquaternary ammonium salt, can significantly enhance lubricant performance.

[0095] Table 1 Test results of kinematic viscosity and viscosity index of different samples

[0096] Sample number 500SN A1 A2 A3 B1 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 89.4 99.6 125.7 166.2 94.6 <![CDATA[Kinematic viscosity (1000 °C, mm 2 / s)]]> 10.7 12.1 16.4 22.3 11.3 Viscosity Index 103 113 140 161 106 Sample number B2 B3 C1 C2 C3 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 107.9 126.1 92.6 102 111 <![CDATA[Kinematic viscosity (100 °C, mm 2 / s)]]> 13.1 15.5 11.1 12.6 14.1 Viscosity Index 117 128 106 117 127

[0097] 2. Friction performance test:

[0098] The tribological performance of a PAMA-based multifunctional lubricant additive based on carboxyl-diquaternary ammonium salt interactions in base oil 500SN was evaluated using an Optimal SRV-IV reciprocating tribometer. The results were compared with those of 500SN, PAO10, a commercial viscosity modifier 8-310, and an uncrosslinked PLA additive. The tribological performance of 500SN, A1, A2, and A3 was tested under the following conditions: a load of 300 N, a frequency of 25 Hz, an amplitude of 1 mm, a duration of 30 min, and a temperature of 25°C. A ball-on-disc contact was used as the friction pair. The upper test ball was an AISI 52100 steel ball with a diameter of 10 mm, and the lower test specimen was an AISI 52100 steel block with a diameter of 24 mm and a height of 8 mm, a hardness of 750-800 HV, and a surface roughness of Ra = 0.012 μm.

[0099] Table 2 shows the test results of average friction coefficient, average wear volume and seizure of different samples. Figure 3 The friction test results of 500SN, A1, A2, and A3 show that under a load of 300N, the average COF of 500SN is as high as 0.19033, and the wear is extremely severe, with seizures occurring. After adding PLA-HODMDAB, the average COF has been significantly improved. When the additive amount is 1wt% PLA-HODMDAB, the average COF drops to 0.17116, and the wear volume decreases significantly, but seizures still exist. When the additive amount is increased to 3wt% or 5wt%, the average COF drops significantly to as low as 0.11552, and is very stable. At the same time, the seizure problem is solved, and the wear volume decreases by an order of magnitude. This shows that as an additive to base oil 500SN, PLA-HODMDAB not only improves its friction reduction performance, but also has excellent anti-wear properties.

[0100] Table 2 Test results of average friction coefficient, average wear volume and seizure of different samples

[0101] Sample number 500SN A1 A2 A3 Average friction coefficient 0.17932 0.17116 0.11552 0.11623 <![CDATA[Average wear volume (10 4 μm 3 )]]> 178.2507 69.2987 20.095 24.2953 Is it stuck? yes yes no no

[0102] 3. Comparative friction test:

[0103] The friction performance of PLA-HODMDAB, a multifunctional lubricating additive based on carboxyl-diquaternary ammonium salt interactions, in base oil 500SN was evaluated using an Optimal SRV-IV reciprocating tribometer. The results were compared with those of 500SN, a commercial viscosity modifier 8-310, and an uncrosslinked PLA additive. The friction performance of 500SN, A2, B2, and C2 was tested under the following conditions: a load of 300 N, a frequency of 25 Hz, an amplitude of 1 mm, a duration of 30 min, and a temperature of 25°C. A ball-on-disc contact was used as the friction pair. The upper test ball was an AISI 52100 steel ball with a diameter of 10 mm, and the lower test specimen was an AISI 52100 steel block with a diameter of 24 mm and a height of 8 mm, a hardness of 750-800 HV, and a surface roughness of Ra = 0.012 μm.

[0104] Table 3 shows the average friction coefficient and seizure test results of different samples. Figure 4 Friction test results for 500SN, A2, B2, and C2 show that under a load of 300N, both 500SN and 500SN with 8-310 exhibited seizure failure. After a 300-400s run-in period, the COF stabilized at 0.19033 and 0.16221, respectively. In contrast, 500SN with the PLA and PLA-HODMDAB proposed in this invention exhibited no seizure failure and exhibited a low friction coefficient, demonstrating that PLA and PLA-HODMDAB improve lubrication stability and possess excellent anti-wear properties.

[0105] Table 3 Average friction coefficient and seizure test results of different samples

[0106] Sample number 500SN A2 B2 C2 Average friction coefficient 0.19033 0.11552 0.12365 0.16221 Is it stuck? yes no no yes

[0107] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A PAMA-type multifunctional lubricating additive based on carboxyl-diquaternary ammonium salt interaction, having the structure shown in Formula I: In formula I, m:n is 1:9-11.

2. The PAMA type multifunctional lubricating additive according to claim 1, characterized in that The m:n is 1:

10.

3. The preparation method of the PAMA type multifunctional lubricating additive according to claim 1 or 2, characterized in that: The following steps are involved: Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer; The poly(lauryl methacrylate-acrylic acid) random copolymer, N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide, an organic solvent and an alkaline solution are mixed and reacted to obtain the PAMA-type multifunctional lubricating additive based on the interaction of carboxyl and diquaternary ammonium salt; The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II: In formula II, m:n is 1:9-11.

4. The preparation method according to claim 3, characterized in that The molar ratio of acrylic acid to lauryl methacrylate is 1:9-11.

5. The preparation method according to claim 3, characterized in that The temperature of the free radical polymerization reaction is 75-90° C., and the time is 7-10 hours.

6. The preparation method according to claim 3, characterized in that The mass ratio of the N,N,N,N',N',N'-hexaoctyldecamethylene diammonium bromide to the poly(lauryl methacrylate-acrylic acid) random copolymer is 1:205-210.

7. The preparation method according to claim 3, characterized in that The alkaline solution includes a NaOH solution, and the mass ratio of NaOH to poly(lauryl methacrylate-acrylic acid) random copolymer in the NaOH solution is 1:25000.

8. Use of the PAMA-type multifunctional lubricating additive based on carboxyl-diquaternary ammonium salt interaction according to claim 1 or 2 in the field of mechanical parts lubrication.

9. A lubricant, characterized in that: The invention comprises a base oil and an auxiliary agent, wherein the auxiliary agent is the PAMA-type multifunctional lubricating additive based on the interaction between carboxyl and diquaternary ammonium salt according to claim 1 or 2.

10. The lubricant according to claim 9, characterized in that The invention comprises the following components in percentage by mass: 95% to 99% of base oil and 1% to 5% of auxiliary agent.

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