A method for constructing a composite film on the surface of a rubber dynamic seal

Abstract

The present invention provides a method for constructing a composite film on the surface of a rubber dynamic seal, comprising the following steps: step 1: functionalization of the rubber surface; step 2: activation of the rubber surface; and step 3: preparation of a Ni-P-based film on the rubber surface. 2+ A series of measures, including particle grafting, effectively achieve the controlled preparation of a hard Ni-P-based film on a flexible rubber surface, achieving excellent film-substrate bonding. Furthermore, by transporting two-dimensional nanomaterials onto Ni particles, the lubricating and corrosion-resistant phase fills the Ni-P film. The resulting film exhibits high toughness and elasticity, leveraging the two-dimensional material's high strength, large surface area, shear resistance, and barrier properties against corrosive media. The resulting composite film exhibits excellent corrosion and wear resistance when applied to saline solutions.

Description

Technical Field

[0001] The invention belongs to the field of material technology, and in particular relates to a method for constructing a composite film on the surface of a rubber dynamic seal. Background Art

[0002] Rubber dynamic seals are widely used in various engineering systems to prevent leakage of lubricating oil or storage media and to prevent the ingress of external dirt or water. However, under high-load and high-speed sliding contact modes, rubber dynamic seals experience high friction and severe wear, and are also corroded by corrosive media, which reduces the reliability and life of the sealing system.

[0003] There are three solutions to this problem: external lubrication, rubber coating, or adding nanoparticles to the rubber matrix. External lubrication uses lubricating oil or grease, but oil is a source of pollution and needs to be replenished regularly. Adding nanoparticles to the rubber body usually deteriorates the mechanical properties of the elastomer and reduces toughness. Therefore, rubber coating seems to be the most promising solution, such as preparing diamond-like carbon (DLC) films on the rubber surface. However, the industrial application of diamond-like carbon films on rubber surfaces faces the following difficulties: film preparation technology is expensive, such as using magnetron sputtering and plasma-enhanced chemical vapor deposition; the all-round film deposition process on the rubber surface is complex and time-consuming; the high stress of the diamond-like carbon film weakens the bonding strength of the film substrate.

[0004] Given the shortcomings of the above methods, chemically plating lubricating and anti-corrosion NiP films on rubber surfaces will be another solution. In fact, chemically plating NiP films on metal surfaces has been widely used to protect metal parts from corrosion and wear. If this technology is applied from metal substrates to polymer substrates, it will directly solve the difficulties faced by the industrial application of diamond-like films on rubber surfaces. The difficulty is that the reaction of chemically plating NiP is an autocatalytic heterogeneous reaction, so activation sites need to be constructed on the rubber surface to promote the reduction of metal ions in the solution to metal and deposit them on the surface of the workpiece. However, rubber is different from metal materials, and conventional ion adsorption and other methods cannot be used to construct this activation layer. Therefore, it is necessary to design a new way to construct this activation layer to ensure excellent membrane-base bonding and the friction reduction and anti-corrosion effect of the composite film. Summary of the Invention

[0005] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a method for constructing a composite film on the surface of a rubber dynamic seal.

[0006] A method for constructing a composite film on the surface of a rubber dynamic seal, comprising:

[0007] Step 1: Rubber surface functionalization

[0008] The rubber sample was immersed in a mixed solution of distilled water, sodium hypochlorite, and hydrochloric acid (mass fraction 37%) in a volume ratio of 100:3-8:2-6; after a period of time, it was rinsed with distilled water.

[0009] Step 2:

[0010] First, dissolve dopamine hydrochloride powder in Tris buffer. Next, add palladium chloride and ammonium chloride in a 1:12 mass ratio to prepare an activation solution. Finally, soak the chlorinated rubber sample from step 1 in this activation solution and stir continuously for 5 hours. A Pd-PDA layer is deposited on the rubber surface at room temperature, and the loosened deposit is thoroughly rinsed with distilled water.

[0011] Step 3:

[0012] Two-dimensional materials loaded with NiSO4 nanoparticles

[0013] First, NiSO4 nanoparticles and refined two-dimensional nanomaterials were dissolved in Tris buffer solution at a mass ratio of 3:1 and ultrasonically mixed and dissolved; secondly, dopamine hydrochloride powder (1 mg / mL) was added and stirred evenly; after 24 hours, the mixture was washed, filtered, and dried to obtain a NiSO4 composite material grafted onto the surface of the two-dimensional material.

[0014] Step 4:

[0015] Preparation of Ni-P-based thin film on rubber surface

[0016] Preparation of alkaline Ni-P composite two-dimensional material solution, 50g·L -1 C6H5O7(NH4)3, 10g·L -1 NH4Cl, 20 g·L -1 NiSO4·6H2O, 10g·L -1 Two-dimensional materials - NiSO4·6H2O and 20g·L -1 NaH2PO2·H2O. Finally, the chlorinated rubber sample from step 2 is electrolessly plated in an alkaline Ni-P composite 2D material solution at a pH of 10.5, a temperature of 90°C, and a duration of 20-35 minutes. This facilitates the Ni-P electroless plating process, allowing the 2D nanomaterial to co-deposit on the rubber surface, forming a Ni-P-based composite film.

[0017] Furthermore, the rubber samples in step one are: nitrile rubber, hydrogenated nitrile rubber, silicone rubber and ethylene propylene rubber, etc.

[0018] Furthermore, the period of time in step 1 is 10-30 minutes.

[0019] Furthermore, the concentration of the Tris buffer solution in step 2 is 10 mM and the pH is 8.5.

[0020] Furthermore, in step 2, the concentrations of palladium chloride and ammonium chloride are 1.0 g / L and 12.0 g / L, respectively.

[0021] Furthermore, in step three, the two-dimensional material is: hexagonal boron nitride, graphene oxide, MXene, etc.

[0022] Furthermore, in step three, dopamine modification promotes the grafting of NiSO4 nanoparticles onto the surface of the two-dimensional material, and the applied solution is a Tris buffer solution.

[0023] Furthermore, a corrosion-resistant and wear-resistant Ni-P composite film on the rubber surface is prepared by the method for constructing a composite film on the surface of a rubber dynamic seal.

[0024] Furthermore, the Ni-P composite film on the rubber surface is used in lubrication and corrosion protection.

[0025] Beneficial effects of the present invention:

[0026] 1. Rubber surface functionalization, i.e. chlorination, is beneficial to increase the wettability and roughness of rubber and strengthen the membrane-base bonding; at the same time, the chlorination process has less destructive power to the environment.

[0027] 2. Using dopamine’s strong affinity for metals, multivalent metal ions (Ag + 、Cu 2+ 、Ni 2+ 、pd 2+ This green method creates multiple binding sites for the subsequent chemical plating of Ni-P based composite films, such as o-quinone, carboxyl, amino, imine and phenol.

[0028] 3. The hard Ni-P based coating does not change the viscoelasticity of the rubber body and will not fall off after repeated bending.

[0029] 4. The introduction of two-dimensional nano-lubricating materials into Ni-P films can optimize the tribological and corrosion properties of the films.

[0030] 5. The present invention does not depend on the shape of the rubber body to change the preparation process, and will be an excellent choice for industrial application.

[0031] 6. The device used in the present invention is simple and easy to operate, and can realize the preparation of Ni-P composite thin films from rubber in an all-round, large-area and low-cost manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the process for preparing Ni-P based thin films from the rubber of the present invention;

[0033] FIG2( a ) is a morphology of NiSO4 grafted onto the surface of two-dimensional hexagonal boron nitride according to the present invention;

[0034] FIG2( b ) is an EDS image of NiSO4 grafted onto the surface of two-dimensional hexagonal boron nitride of the present invention;

[0035] Figure 3 (a) is a morphology diagram of the original rubber of the present invention;

[0036] Figure 3(b) shows the morphology of the Ni-P based film on the rubber surface. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] Example 1

[0039] like Figure 1 As shown, this embodiment provides a method for constructing a composite film on the surface of a rubber dynamic seal, comprising the following steps:

[0040] (1) Rubber surface functionalization

[0041] A nitrile rubber sample with a length × width × thickness of 4 cm, 2 cm, and 1 mm, respectively, was immersed in a mixed solution of 100 mL of distilled water, 5 mL of sodium hypochlorite, and 2 mL of 37% hydrochloric acid; after 30 minutes, it was rinsed with distilled water.

[0042] (2) Rubber surface activation

[0043] First, 300 mg of dopamine hydrochloride powder was dissolved in 300 mL of Tris buffer. Next, 0.3 g of palladium chloride and 3.6 g of ammonium chloride were added to prepare an activation solution. Finally, a sample of chlorinated nitrile rubber was immersed in this solution and stirred continuously for 5 hours. A Pd-PDA layer was deposited on the rubber surface at room temperature, and the loosened deposit was thoroughly rinsed with distilled water.

[0044] (3) Preparation of Ni-P-based thin film on rubber surface

[0045] First, 900 mg of hexagonal boron nitride and 2.7 g of NiSO₄ were added to 300 mL of Tris buffer solution and ultrasonicated to form a uniform colloidal solution. Then, 300 mg of dopamine hydrochloride was added and stirred at 25°C for 24 hours. Finally, the mixture was centrifuged at 2500 rpm for 5 minutes, and the supernatant was collected, filtered, dried, and washed several times to obtain hexagonal boron nitride-loaded NiSO₄ nanoparticles. Figure 2(a)-Figure 2(b)As shown in the figure, it can be found that NiSO4 is evenly grafted onto the surface of the two-dimensional boron nitride material. Finally, a Ni-P-based plating solution is prepared by using the ingredients and ratios shown in the table below. The activated nitrile rubber is immersed in the solution and left for 25 minutes. Compared with the original rubber sheet, the color of the rubber sheet after coating changes significantly, and the Ni-P-based film covers the rubber surface in all directions, as shown in the figure below. Figure 3(a)-Figure 3(b) shown.

[0046] Table 1 Composition, ratio and related parameters of chemical Ni-P plating solution

[0047]

[0048]

[0049] (4) Verification of friction and corrosion performance of Ni-P based films on rubber surfaces

[0050] Environment: 3.5% sodium chloride solution

[0051] Among them, the friction condition adopts the ball-disk rotation mode, the rotation radius is 4mm, the normal load is 1.0N, and the friction pair is a φ6mm GCr15 steel ball.

[0052] Test results: The friction coefficient reached as low as 0.05, showing excellent tribological properties; after immersion for one week, the Ni-P-based film on the rubber surface did not produce obvious swelling and corrosion.

[0053] Example 2

[0054] like Figure 1 As shown, this embodiment provides a method for constructing a composite film on the surface of a rubber dynamic seal, comprising the following steps:

[0055] (1) Rubber surface functionalization

[0056] An EPDM rubber sample with a length × width × thickness of 4 cm × 2 cm × 1 mm was immersed in a mixed solution of 100 mL of distilled water, 5 mL of sodium hypochlorite, and 3 mL of 37% hydrochloric acid; after 30 minutes, it was rinsed with distilled water.

[0057] (2) Rubber surface activation

[0058] First, 300 mg of dopamine hydrochloride powder was dissolved in 300 mL of Tris buffer. Next, 0.2 g of palladium chloride and 2.4 g of ammonium chloride were added to prepare an activation solution. Finally, a chlorinated ethylene propylene rubber sample (4 cm long x 2 cm wide x 1 mm thick) was immersed in the solution and stirred continuously for 5 hours. A Pd-PDA layer was deposited on the rubber surface at room temperature, and the loosened deposit was thoroughly rinsed with distilled water.

[0059] (3) Preparation of Ni-P-based thin film on rubber surface

[0060] First, 900 mg of hexagonal boron nitride and 2.7 g of NiSO₄ were added to 300 mL of Tris buffer solution and ultrasonically stirred to form a homogeneous colloidal solution. Next, 300 mg of dopamine hydrochloride was added and stirred at 25°C for 24 hours. Finally, the solution was centrifuged at 2500 rpm for 5 minutes. The supernatant was collected, filtered, dried, and washed several times to obtain hexagonal boron nitride-loaded NiSO₄ nanoparticles. Finally, a Ni-P-based plating solution was prepared using the ingredients and ratios shown in the table below. The activated nitrile rubber was immersed in the solution and allowed to stand for 25 minutes.

[0061] Table 1 Composition, ratio and related parameters of chemical Ni-P plating solution

[0062]

[0063] (4) Verification of friction and corrosion performance of Ni-P based films on rubber surfaces

[0064] Environment: 3.5% sodium chloride solution

[0065] Among them, the friction condition adopts a reciprocating mode, with a length of 5 mm, a normal load of 3.0 N, and a friction pair of GCr15 steel balls with a diameter of 6 mm.

[0066] Test results: The friction coefficient reached as low as 0.08, showing excellent tribological properties; after immersion for one week, the edges of the Ni-P-based film on the rubber surface showed slight signs of falling off.

[0067] Example 3

[0068] like Figure 1 As shown, this embodiment provides a method for constructing a composite film on the surface of a rubber dynamic seal, comprising:

[0069] (1) Rubber surface functionalization

[0070] A hydrogenated nitrile rubber sealing ring with an inner diameter of 5 cm and an outer diameter of 6 cm was immersed in a mixed solution of 100 mL of distilled water, 5 mL of sodium hypochlorite, and 2 mL of 37% hydrochloric acid; after 30 minutes, it was rinsed with distilled water.

[0071] (2) Rubber surface activation

[0072] First, 300 mg of dopamine hydrochloride powder was dissolved in 300 mL of Tris buffer. Next, 0.3 g of palladium chloride and 3.6 g of ammonium chloride were added to prepare an activation solution. Finally, a sample of chlorinated hydrogenated nitrile rubber was immersed in this solution and stirred continuously for 5 hours. A Pd-PDA layer was deposited on the rubber surface at room temperature, and the loosened deposit was thoroughly rinsed with distilled water.

[0073] (3) Preparation of Ni-P-based thin film on rubber surface

[0074] First, 900 mg of hexagonal boron nitride and 2.7 g of NiSO₄ were added to 300 mL of Tris buffer solution and ultrasonically stirred to form a homogeneous colloidal solution. Next, 300 mg of dopamine hydrochloride was added and stirred at 25°C for 24 hours. Finally, the solution was centrifuged at 2500 rpm for 5 minutes. The supernatant was collected, filtered, dried, and washed several times to obtain hexagonal boron nitride-loaded NiSO₄ nanoparticles. Finally, a Ni-P-based plating solution was prepared using the ingredients and ratios shown in the table below. The activated hydrogenated nitrile rubber was immersed in the solution and allowed to stand for 25 minutes.

[0075] Table 1 Composition, ratio and related parameters of chemical Ni-P plating solution

[0076]

[0077] (4) Verification of corrosion performance of Ni-P based film on rubber surface

[0078] Environment: 3.5% sodium chloride solution

[0079] After immersion for one week, the Ni-P-based film on the rubber surface showed no obvious swelling or corrosion, and showed no signs of falling off after repeated bending.

[0080] Example 4

[0081] like Figure 1 As shown, this embodiment provides a method for constructing a composite film on the surface of a rubber dynamic seal, comprising:

[0082] (1) Rubber surface functionalization

[0083] A nitrile rubber sample with a length × width × thickness of 4 cm, 2 cm, and 1 mm, respectively, was immersed in a mixed solution of 100 mL of distilled water, 5 mL of sodium hypochlorite, and 2 mL of 37% hydrochloric acid; after 30 minutes, it was rinsed with distilled water.

[0084] (2) Rubber surface activation

[0085] First, 300 mg of dopamine hydrochloride powder was dissolved in 300 mL of Tris buffer. Next, 0.3 g of palladium chloride and 3.6 g of ammonium chloride were added to prepare an activation solution. Finally, a sample of chlorinated nitrile rubber was immersed in this solution and stirred continuously for 5 hours. A Pd-PDA layer was deposited on the rubber surface at room temperature, and the loosened deposit was thoroughly rinsed with distilled water.

[0086] (3) Preparation of Ni-P-based thin film on rubber surface

[0087] First, 900 mg of MXene and 2.7 g of NiSO₄ were added to 300 mL of Tris buffer solution and ultrasonically stirred to form a homogeneous colloidal solution. Next, 300 mg of dopamine hydrochloride was added and stirred at 25°C for 24 hours. Finally, the solution was centrifuged at 1500 rpm for 5 minutes. The supernatant was collected, filtered, dried, and washed several times to obtain MXene-loaded NiSO₄ nanoparticles. Finally, a Ni-P-based plating solution was prepared using the ingredients and ratios shown in the table. The activated nitrile rubber was immersed in the solution and allowed to stand for 30 minutes.

[0088] Table 1 Composition, ratio and related parameters of chemical Ni-P plating solution

[0089]

[0090] (4) Verification of friction and corrosion performance of Ni-P based films on rubber surfaces

[0091] Environment: 3.5% sodium chloride solution

[0092] Among them, the friction condition adopts the ball-disk rotation mode, the rotation radius is 4mm, the normal load is 1.0N, and the friction pair is a φ6mm GCr15 steel ball.

[0093] Test results: The friction coefficient reached as low as 0.1, showing good tribological properties; after immersion for one week, the edges of the Ni-P-based film on the rubber surface showed signs of slight falling off.

[0094] The present invention utilizes the property that dopamine can adhere to the surface of the substrate and form a firm polydopamine layer in an aqueous solution after undergoing oxidative polymerization under alkaline aerobic conditions. The polymerization process is designed to carry activated particles to the rubber surface for deposition, providing a new idea for polymer surface activation. Secondly, in order to strengthen the non-covalent force of the polydopamine self-assembled film, the rubber surface is preliminarily chlorinated to enhance the surface hydrophilicity and reduce the surface energy. This method has universal applicability to polymer materials. Finally, we achieved the filling of two-dimensional materials into Ni-P film by carrying two-dimensional nanomaterials by NiSO4, and optimized the corrosion resistance and wear resistance of Ni-P film. The results of the study showed that compared with the original rubber, the rubber surface coated with this type of Ni-P-based film has a 10-fold longer service life and a 9-fold lower friction coefficient when serving in a salt solution, and the corrosion resistance and anti-swelling properties are greatly improved.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for constructing a composite film on the surface of a rubber dynamic seal, characterized in that: include: Step 1: Soak the rubber sample in a mixed solution of distilled water, sodium hypochlorite, and hydrochloric acid in a volume ratio of 100:3-8:2-6, where the mass fraction of the hydrochloric acid is 37%; wait for a period of time, and then rinse with distilled water; Step 2: First, dissolve dopamine hydrochloride powder in Tris buffer solution. Then, add palladium chloride and ammonium chloride in a mass ratio of 1:12 to prepare an activation solution. Finally, soak the chlorinated rubber sample from step 1 in the activation solution and stir continuously for 5 hours. A Pd-PDA layer will be deposited on the rubber surface at room temperature. The loose sediment will be thoroughly rinsed with distilled water. Step 3: First, dissolve NiSO4 nanoparticles and refined two-dimensional nanomaterials in a Tris buffer solution at a mass ratio of 3:1 and mix and dissolve them by ultrasonication; then add dopamine hydrochloride powder at a concentration of 1 mg / mL and stir evenly; after 24 hours, wash, filter, and dry to obtain a NiSO4 composite material grafted onto the surface of the two-dimensional material, wherein the two-dimensional material is: hexagonal boron nitride, graphene oxide, and MXene; Step 4: The chlorinated rubber with Pd-PDA deposited on the rubber surface of step 2 is placed in an alkaline Ni-P composite two-dimensional material solution for chemical plating at a pH of 10.5, a temperature of 90°C, and a time of 20-35 minutes to obtain a Ni-P based composite film; The alkaline Ni-P composite two-dimensional material solution consists of 50 g·L -1 C6H5O7(NH4)3, 10 g·L -1 NH4Cl, 20 g·L -1 NiSO4·6H2O, 10 g·L -1 Two-dimensional materials-NiSO4 and 20 g·L -1 Composition: NaH2PO2·H2O.

2. The method for constructing a composite film on the surface of a rubber dynamic seal according to claim 1, characterized in that: The rubber samples in step 1 are: nitrile rubber, hydrogenated nitrile rubber, and silicone rubber.

3. The method for constructing a composite film on the surface of a rubber dynamic seal according to claim 1, characterized in that: The time period in step one is 10-30 minutes.

4. The method for constructing a composite film on the surface of a rubber dynamic seal according to claim 1, characterized in that: The concentration of the Tris buffer solution in step 2 is 10 mM and the pH is 8.

5.

5. A Ni-P composite film produced according to the method for constructing a composite film on the surface of a rubber dynamic seal according to any one of claims 1 to 4.

6. Application of the Ni-P composite film produced according to the method for constructing a composite film on the surface of a rubber dynamic seal according to any one of claims 1 to 4 in lubrication and corrosion protection.

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