A cobaltocene-based zwitterionic polymer and lubricating fluid, and methods of making and using the same

Abstract

This invention belongs to the field of functional polymer materials, specifically relating to a cobalt-ceramic-based zwitterionic polymer and a lubricant, as well as their preparation method and application. The cobalt-ceramic-based zwitterionic polymer provided by this invention has cobalt-ceramic cationic groups and sulfonate anionic groups. The cobalt-ceramic groups have high potential energy and exhibit dynamic equilibrium adsorption and desorption behavior on steel surfaces, forming a protective layer through multiple interfacial interactions. The sulfonate groups have a strong affinity for water molecules, forming a highly hydrated interface. The cobalt-ceramic groups and sulfonate groups have low binding energy. Through the synergistic effect of the interaction between the cobalt-ceramic groups and the metal surface and the strong hydration of the sulfonate groups, excellent lubrication can be achieved, resulting in excellent anti-wear and friction-reducing effects on metal / metal friction pairs under different friction loads and frequencies.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer materials technology, specifically relating to a cobalt-cerotropy-based zwitterionic polymer and a lubricant, as well as their preparation method and application. Background Technology

[0002] Friction and wear phenomena often lead to reduced mechanical efficiency and shortened equipment lifespan in modern industrial systems, resulting in significant energy and economic losses. To improve energy efficiency and reduce energy loss, lubricants are typically introduced between friction surfaces to reduce friction and save energy. Among these, water-based lubricants are receiving increasing attention due to their advantages such as low cost, high cooling performance, non-flammability, and environmental friendliness. However, water's low viscosity and poor load-bearing capacity often lead to suboptimal lubrication under boundary lubrication mechanisms and increase the risk of corrosion in metal friction pairs. Most water-based lubricant additives still face limitations such as poor dispersibility and stability in aqueous solutions and low interfacial dynamic adsorption / desorption activity.

[0003] Zwitterionic polyelectrolytes are polymers containing the same total number of positive / negative charges in repeating units. These materials have become ideal candidates for water-based lubricants due to their low cost, strong hydration capacity, and low toxicity. Traditional zwitterionic polyelectrolyte structures mainly include polysulfobetaine, polycarboxybetaine, and polyphosphocholine. Zwitterionic polyelectrolytes primarily enhance lubrication performance through a hydration lubrication mechanism. On one hand, they can act as surface modifiers to enhance the hydrophilicity of hydrophobic lubricating materials, thereby improving their dispersibility in aqueous environments, or be used for surface modification to prepare lubricating coatings. On the other hand, nano-self-assembled structures induced by their specific topological structures or supramolecular interactions can also serve as highly efficient lubricating additives. However, lubricating additives based on traditional polybetaine zwitterionic polyelectrolytes still suffer from weak adhesion to metal surfaces and poor interfacial adsorption capacity, thus limiting their lubrication performance under complex working conditions such as high mechanical shear and high load. Summary of the Invention

[0004] The purpose of this invention is to provide a cobalt-cerotropy-based zwitterionic polymer and a lubricant, as well as their preparation method and application. The cobalt-cerotropy-based zwitterionic polymer provided by this invention can achieve excellent lubrication effect by synergistically combining the strong hydration effect of sulfonic acid groups and the interaction between cobalt-cerotropy groups and metal surfaces.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: A cobalt-1,4-diocene-based zwitterionic polymer having the structure shown in Formula I: Formula I; In Equation I, n ranges from 5 to 500.

[0006] This invention provides a method for preparing the cobalt-cerotropy-based zwitterionic polymer described above, comprising the following steps: A cobalt-ceramic zwitterionic monomer, an initiator, and water are mixed and polymerized to obtain the cobalt-ceramic zwitterionic polymer. The cobalt-cerotropy-based zwitterionic monomer has the structure shown in Formula II: Formula II.

[0007] Preferably, the mixing includes dissolving a cobalt-based zwitterionic monomer and an initiator in water to form a cobalt-based zwitterionic monomer solution and an initiator solution, respectively, and then mixing the cobalt-based zwitterionic monomer solution and the initiator solution.

[0008] Preferably, the concentration of the cobalt-based zwitterionic monomer in the cobalt-based zwitterionic monomer solution is 0.01~10 mol / L; the concentration of the initiator in the initiator solution is 25~45 mg / mL; the initiator is persulfate; and the volume ratio of the cobalt-based zwitterionic monomer solution to the initiator solution is 10~100:1.

[0009] Preferably, the polymerization reaction is carried out at a temperature of 30~80℃ for a time of 6~48 h.

[0010] Preferably, the polymerization reaction further includes mixing the mixed solution obtained from the polymerization reaction with an organic solvent to precipitate the product, wherein the precipitate is the cobalt-based zwitterionic polymer.

[0011] Preferably, the organic solvent comprises tetrahydrofuran, the precipitation is carried out under ice bath conditions, and the precipitation time is 0.5 to 2.5 h.

[0012] The present invention provides the application of the cobalt-cerotropy-based zwitterionic polymer described in the above technical solution or the cobalt-cerotropy-based zwitterionic polymer prepared by the above preparation method as a water lubricating additive.

[0013] The present invention provides a lubricant comprising water and a water-lubricating additive, wherein the water-lubricating additive is the cobalt-ceramic-based zwitterionic polymer described in the above technical solution or the cobalt-ceramic-based zwitterionic polymer prepared by the above preparation method.

[0014] Preferably, the concentration of the water-lubricating additive in the lubricating fluid is 5~100 mg / mL.

[0015] This invention provides a cobalt-ceramic-based zwitterionic polymer containing cobalt-ceramic cationic groups and sulfonate anionic groups. The cobalt-ceramic groups possess high electrical potential energy and exhibit dynamic equilibrium adsorption and desorption behavior on steel surfaces, forming a protective layer through multiple interfacial interactions (including electrostatic attraction, coordination, and hydrophobic / hydrophilic effects). Simultaneously, the sulfonate groups, due to their strong affinity for water molecules, form a highly hydrated interface.

[0016] The cobalt-1,4-diocene-based zwitterionic polymer provided by this invention serves as a water-based lubricating additive. Excellent lubrication is achieved through the synergistic effect of the interaction between the cobalt-1,4-diocene groups and the metal surface, and the strong hydration of the sulfonic acid groups. Furthermore, the Y-shaped molecular configuration results in a low binding energy between the cobalt-1,4-diocene cations and the sulfonic acid anions, and promotes the self-association of zwitterions through electrostatic interactions, further enhancing the self-supporting capacity and stability of the lubricating film. This enables it to exhibit excellent anti-wear and friction-reducing effects on metal / metal friction pairs under different friction loads and frequencies.

[0017] This invention provides a method for preparing a cobalt-based zwitterionic polymer, which is obtained by subjecting a cobalt-based zwitterionic monomer to a simple free radical polymerization reaction. The preparation method is simple and the molecular weight of the obtained cobalt-based zwitterionic polymer is controllable. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the synthesis of cobalt-cerotropy-based zwitterionic polymers. Figure 2 The structural formula and 1H NMR spectrum of the cobalt-based zwitterionic polymer prepared in Example 1 before and after polymerization are shown below. Figure 3 Friction coefficient curves and wear volume comparison diagrams for pure water, lubricants prepared in Example 3 and Example 4; Figure 4 Friction coefficient curves and wear volume comparison diagrams for pure water and the lubricant prepared in Example 5; Figure 5 Friction coefficient curves and wear volume comparison diagrams for pure water, lubricants prepared in Examples 6 and 7. Detailed Implementation

[0019] This invention provides a cobalt-1,4-diocene-based zwitterionic polymer having the structure shown in Formula I: Formula I; In Equation I, n is 5~500, and can be further 100~200.

[0020] This invention provides a cobalt-ceramic-based zwitterionic polymer containing cobalt-ceramic cationic groups and sulfonate anionic groups. The cobalt-ceramic groups possess high electrical potential energy and exhibit dynamic equilibrium adsorption and desorption behavior on steel surfaces, forming a protective layer through multiple interfacial interactions (including electrostatic attraction, coordination, and hydrophobic / hydrophilic effects). Simultaneously, the sulfonate groups, due to their strong affinity for water molecules, form a highly hydrated interface.

[0021] This invention provides a method for preparing the cobalt-cerotropy-based zwitterionic polymer described above, comprising the following steps: A cobalt-ceramic zwitterionic monomer, an initiator, and water are mixed and polymerized to obtain the cobalt-ceramic zwitterionic polymer; the cobalt-ceramic zwitterionic monomer has the structure shown in Formula II: Formula II.

[0022] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0023] As one embodiment of the present invention, the preparation method of the cobalt-based zwitterionic monomer is described in Chinese Patent CN117126425A.

[0024] In one embodiment of the present invention, the initiator is a persulfate, specifically ammonium persulfate.

[0025] The initiator used in this invention is a water-soluble initiator, which can stably decompose in an aqueous system to generate free radicals, initiating the polymerization of carbon-carbon double bonds in cobalt-based zwitterionic monomers. This avoids the problems of poor dispersibility and low initiation efficiency of non-water-soluble initiators in aqueous systems, ensuring the normal growth of polyelectrolyte molecular chains and forming the structure shown in Formula I. Furthermore, the initiator disclosed in this invention does not undergo side reactions with the monomers, and its initiation efficiency is high and stable at the polymerization temperature, enabling the preparation of polyelectrolytes with uniform polymerization degree. This ensures the stability of the adsorption film and hydration layer formed by the lubricant on the metal surface, achieving a continuous and consistent friction-reducing and anti-wear effect.

[0026] In one embodiment of the present invention, the mixing specifically includes: dissolving a cobalt-based zwitterionic monomer and an initiator in water to form a cobalt-based zwitterionic monomer solution and an initiator solution, respectively; and mixing the cobalt-based zwitterionic monomer solution and the initiator solution; the water may specifically be deoxygenated deionized water; the concentration of the cobalt-based zwitterionic monomer in the cobalt-based zwitterionic monomer solution is 0.01~10 mol / L, more preferably 0.1~5 mol / L; the concentration of the initiator in the initiator solution may be 25~45 mg / mL, more preferably 28.78~44.3 mg / mL; the present invention can regulate the degree of polymerization of the generated cobalt-based zwitterionic polymer by controlling the concentration of the initiator solution.

[0027] In one embodiment of the present invention, the volume ratio of the cobalt-based zwitterionic monomer solution to the initiator solution can be 10~100:1.

[0028] In one embodiment of the present invention, the temperature of the polymerization reaction can be 30~80℃, more preferably 50~80℃, specifically 60℃, 70℃ or 80℃; the time of the polymerization reaction can be 6~48 h, more preferably 24~48 h, specifically 24 h, 30 h, 36 h, 40 h or 48 h.

[0029] As one embodiment of the present invention, the polymerization reaction further includes: mixing the mixed solution obtained from the polymerization reaction with an organic solvent to precipitate, wherein the precipitate is the cobalt-cerophenone-based zwitterionic polymer.

[0030] In one embodiment of the present invention, the organic solvent includes tetrahydrofuran, and the precipitation is carried out under ice bath conditions; the precipitation time is 0.5~2.5h.

[0031] In one embodiment of the present invention, after the precipitation is completed, the precipitate is collected and dried to obtain the cobalt-based zwitterionic polymer; the drying is carried out in a vacuum drying oven, and the drying temperature can be 30~80℃, specifically 50℃, and the drying time can be 6~24 h, specifically 12 h.

[0032] The present invention provides the application of the cobalt-cerotropy-based zwitterionic polymer described in the above technical solution or the preparation method of the cobalt-cerotropy-based zwitterionic polymer as a water lubricating additive.

[0033] The present invention provides a lubricant comprising water and a water-lubricating additive, wherein the water-lubricating additive is a cobalt-ceramic-based zwitterionic polymer as described in the above technical solution or a cobalt-ceramic-based zwitterionic polymer prepared by the preparation method of the cobalt-ceramic-based zwitterionic polymer.

[0034] In one embodiment of the present invention, the concentration of the water-lubricating additive in the lubricating fluid is 5~100 mg / mL, and more preferably 50~100 mg / mL.

[0035] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments thereof. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Figure 1 This is a flowchart of the synthesis of cobalt-cerotropy-based zwitterionic polymers; based on Figure 1 A cobalt-cerocenyl-based zwitterionic polymer was prepared, and the structure of the cobalt-cerocenyl-based zwitterionic polymer is shown in Formula I: Formula I; In Equation I, n is 5 to 500.

[0037] Example 1 200 mg of cobalt-based zwitterionic monomer was dissolved in 0.29 mL of deoxygenated deionized water to obtain solution A (1.33 mol / L); 22.15 mg of ammonium persulfate (APS) was dissolved in 0.5 mL of deoxygenated deionized water to obtain solution B; under a nitrogen atmosphere, 10 μL of solution B was transferred and mixed with 0.29 mL of solution A, and the mixture was reacted at 70 °C for 48 h; the resulting mixture was precipitated in tetrahydrofuran under ice bath conditions for 1 h, and the precipitate was collected and dried in a vacuum drying oven at 50 °C for 12 h to obtain cobalt-based zwitterionic polymer (n=150).

[0038] Figure 2 The structural formula and 1H NMR spectrum of the cobalt-cerocenium-based zwitterionic polymer prepared in Example 1 before and after polymerization; according to Figure 2 It can be seen that the NMR peak of H on the carbon-carbon double bond in the cobalt-cerocenium-based zwitterionic monomer disappears after polymerization, indicating that the cobalt-cerocenium-based zwitterionic polymer was successfully prepared.

[0039] Example 2 200 mg of cobalt-based zwitterionic monomer was dissolved in 0.29 mL of deoxygenated deionized water to obtain solution A; 7.19 mg of ammonium persulfate (APS) was dissolved in 0.5 mL of deoxygenated deionized water to obtain solution B; under a nitrogen atmosphere, 5 μL of solution B was transferred and mixed with 0.29 mL of solution A, and the mixture was reacted at 80 °C for 24 h; the resulting mixture was precipitated in tetrahydrofuran under ice bath conditions for 2.5 h, and the precipitate was collected and dried in a vacuum drying oven at 50 °C for 12 h to obtain cobalt-based zwitterionic polymer (n=300).

[0040] Example 3 The cobalt-based zwitterionic polymer prepared in Example 1 was dissolved in deionized water to obtain a lubricating fluid with a concentration of 50 mg / mL. The lubrication performance of the steel / steel friction pair was tested using a reciprocating friction method. The test load was 10 N, the test frequency was 5 Hz, and the test stroke was 1 mm. The results showed that the lubricating fluid prepared in Example 3 reduced the coefficient of friction by 51.31% and the wear volume by 71.79% compared to water.

[0041] Example 4 The cobalt-based zwitterionic polymer prepared in Example 1 was dissolved in deionized water to obtain a lubricating fluid with a concentration of 100 mg / mL. The lubrication performance of the steel / steel friction pair was tested using a reciprocating friction method. The test load was 10 N, the test frequency was 5 Hz, and the test stroke was 1 mm. The results showed that the lubricating fluid prepared in Example 4 reduced the coefficient of friction by 52.18% and the wear volume by 72.14% compared to water.

[0042] Effect diagrams of Examples 3 and 4: Figure 3 Friction coefficient curves and wear volume comparison diagrams for pure water, lubricants prepared in Example 3 and Example 4; Figure 3 In the middle (a), the friction coefficient of pure water and the lubricating fluid prepared in Example 3 and Example 4 is a graph showing the relationship between time; Figure 3 (b) is a graph showing the relationship between wear mark depth and lateral distance for pure water, lubricants prepared in Examples 3 and 4; Figure 3 (c) is a bar chart showing the wear volume of pure water, the lubricating fluid prepared in Examples 3 and 4. Figure 3 As shown in (a), the coefficient of friction with added lubricant is significantly reduced compared to that with water, and the coefficient of friction decreases further with increasing concentration of the product from Example 1. These results indicate that the cobalt-ceramic-based zwitterionic polymer exhibits excellent friction-reducing effects. See also Figure 3 (b) and Figure 3In (c), the wear of the lubricant was significantly reduced compared to that of water, and the wear volume decreased further with the increase of the concentration of the product of Example 1, further demonstrating that the anti-wear performance of water can be effectively improved after adding the product of Example 1.

[0043] Example 5 The cobalt-based zwitterionic polymer prepared in Example 1 was dissolved in deionized water to obtain a lubricating fluid with a concentration of 50 mg / mL. The lubrication performance of the steel / steel friction pair was tested using a reciprocating friction method. The test load was 20 N, the test frequency was 5 Hz, and the test stroke was 1 mm. The results showed that the lubricating fluid prepared in Example 5 reduced the coefficient of friction by 57.10% and the wear volume by 75.43% compared to water.

[0044] Rendering of Example 5: Figure 4 Friction coefficient curves and wear volume comparison diagrams for pure water and the lubricant prepared in Example 5; Figure 4 In the middle (a), the friction coefficient of pure water and the lubricant prepared in Example 5 are plotted as a function of time. Figure 4 (b) is a graph showing the relationship between wear mark depth and lateral distance for pure water and the lubricant prepared in Example 5; Figure 4 (c) is a bar chart of wear volume for pure water and the lubricant prepared in Example 5. Figure 4 The results show that the friction coefficient of the added lubricant is significantly reduced compared to that of water. At the same time, the wear of the lubricant is significantly reduced compared to that of water. Furthermore, the increase in test load compared to Example 3 does not affect the friction reduction effect of the cobalt-based zwitterionic polymer.

[0045] Example 6 The cobalt-based zwitterionic polymer prepared in Example 2 was dissolved in deionized water to obtain a lubricating fluid with a concentration of 50 mg / mL. The lubrication performance of the steel / steel friction pair was tested using a reciprocating friction method. The test load was 10 N, the test frequency was 3 Hz, and the test stroke was 1 mm. The results showed that the coefficient of friction of the lubricating fluid prepared in Example 6 was reduced by 58.20% compared to that of water, and the wear volume was reduced by 76.07%.

[0046] Example 7 The cobalt-based zwitterionic polymer prepared in Example 2 was dissolved in deionized water to obtain a lubricating fluid with a concentration of 50 mg / mL. The lubrication performance of the steel / steel friction pair was tested using a reciprocating friction method. The test load was 10 N, the test frequency was 7 Hz, and the test stroke was 1 mm. The results showed that the coefficient of friction of the lubricating fluid prepared in Example 7 was reduced by 55.81% compared to that of water, and the wear volume was reduced by 71.08%.

[0047] Renderings of Examples 6 and 7: Figure 5 Friction coefficient curves and wear volume comparison diagrams for pure water, lubricants prepared in Examples 6 and 7; Figure 5 In the middle (a), the friction coefficient of pure water and the lubricating fluid prepared in Example 6 and Example 7 is a graph showing the relationship between time; Figure 5 (b) is a graph showing the relationship between wear mark depth and lateral distance for pure water, lubricants prepared in Examples 6 and 7; Figure 5 (c) is a bar chart of wear volume for pure water and the lubricating fluids prepared in Examples 6 and 7. Figure 5 The results showed that the coefficient of friction with added lubricant was significantly reduced compared to water, and the wear caused by lubricant was significantly less than that caused by water. Furthermore, compared to Example 3, increases or decreases in test frequency and changes in the degree of polymerization had little effect on the friction-reducing effect of the cobalt-based zwitterionic polymer.

[0048] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A cobalt-cerocenyl-based zwitterionic polymer, characterized in that, It has the structure shown in Equation I: Equation I; In Equation I, n ranges from 5 to 500.

2. The method for preparing the cobalt-based zwitterionic polymer of claim 1, comprising the following steps: A cobalt-ceramic zwitterionic monomer, an initiator, and water are mixed and polymerized to obtain the cobalt-ceramic zwitterionic polymer. The cobalt-cerotropy-based zwitterionic monomer has the structure shown in Formula II: Formula II.

3. The preparation method according to claim 2, characterized in that, The mixing process includes dissolving a cobalt-based zwitterionic monomer and an initiator in water to form a cobalt-based zwitterionic monomer solution and an initiator solution, respectively, and then mixing the cobalt-based zwitterionic monomer solution and the initiator solution.

4. The preparation method according to claim 3, characterized in that, The concentration of the cobalt-based zwitterionic monomer in the solution is 0.01~10 mol / L; the concentration of the initiator in the initiator solution is 25~45 mg / mL; the initiator is persulfate; and the volume ratio of the cobalt-based zwitterionic monomer solution to the initiator solution is 10~100:

1.

5. The preparation method according to claim 2, characterized in that, The polymerization reaction is carried out at a temperature of 30~80℃ for a time of 6~48 h.

6. The preparation method according to claim 2, characterized in that, The polymerization reaction is followed by mixing the mixed solution obtained from the polymerization reaction with an organic solvent to precipitate the product, and the precipitate is the cobalt-based zwitterionic polymer.

7. The preparation method according to claim 6, characterized in that, The organic solvent includes tetrahydrofuran, and the precipitation is carried out under ice bath conditions for a time of 0.5 to 2.5 h.

8. The application of the cobalt-ceramic zwitterionic polymer of claim 1 or the cobalt-ceramic zwitterionic polymer prepared by any one of claims 2 to 7 as a water lubricating additive.

9. A lubricating fluid, characterized in that, It includes water and a water-lubricating additive, wherein the water-lubricating additive is the cobalt-ceramic-based zwitterionic polymer of claim 1 or the cobalt-ceramic-based zwitterionic polymer prepared by the preparation method of any one of claims 2 to 7.

10. The lubricant according to claim 9, characterized in that, The concentration of the water-lubricating additive in the lubricant is 5~100 mg / mL.

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