A modified two-dimensional nanomaterial, its preparation method and application

Abstract

The present disclosure relates to a modified two-dimensional nanomaterial, a preparation method thereof, and an application thereof. The modified two-dimensional nanomaterial is a two-dimensional nanomaterial having grafting groups on its surface, and the grafting groups include any one or a combination of at least two of SO3−, -PO3−, or -N + - groups. The prepared modified two-dimensional nanomaterial can improve the hydrophilicity of the surface of the polymer matrix material, enhance its hydration effect, and is more likely to form a water film under water lubrication conditions to achieve hydration lubrication, which helps to achieve the effect of reducing friction and wear.

Description

Technical Field

[0001] The present disclosure relates to the field of material technology, and particularly to a modified two-dimensional nanomaterial, a preparation method thereof, and an application thereof. Background Art

[0002] Polymers and their composite materials can be widely used as friction pair components in fields such as aerospace, chemical engineering, and ocean engineering due to their characteristics such as light weight, high specific strength, self-lubrication, and chemical corrosion resistance. In ocean engineering equipment, replacing metals with polymers and their composite materials for friction pairs may be a future development trend. However, materials such as ultra-high molecular weight polyethylene and polyether ether ketone also have some defects, such as being chemically inert on the surface, having poor surface wettability, having a high friction coefficient and poor wear resistance under liquid lubrication conditions, which limit their application in ocean engineering. How to improve their lubrication performance has received extensive attention from researchers in recent years.

[0003] Two-dimensional materials with a layered structure have atomic-level thickness, ultra-low shear strength between layers, a high specific surface area, and surface chemical stability. In two-dimensional materials, atoms in the same atomic layer are bonded by covalent bonds to form a single-layer structure with high modulus and high strength; the low shear resistance between adjacent atomic layers makes the atomic layers easy to slide; the high specific surface area makes them easily adsorbed onto the contact surface, thus preventing direct contact between the friction pairs. Therefore, incorporating two-dimensional materials into polymer materials is expected to improve the lubrication performance of polymer materials and achieve the effect of reducing friction and wear. Summary of the Invention

[0004] To solve at least one of the above technical problems, the present disclosure provides a modified two-dimensional nanomaterial, a preparation method thereof, and an application thereof.

[0005] As one aspect, the present disclosure provides a modified two-dimensional nanomaterial, which is a two-dimensional nanomaterial with grafting groups on the surface, and the grafting groups include any one or a combination of at least two of SO3-, -PO3-, or -N + - groups.

[0006] In some embodiments of the present disclosure, the two-dimensional nanomaterial is selected from one or more of nanomolybdenum disulfide, nanoboron nitride, and nano-graphene oxide.

[0007] As another aspect, the present disclosure provides a preparation method of the above-mentioned modified two-dimensional nanomaterial, and the preparation method includes the following steps: reacting the two-dimensional nanomaterial with a compound containing grafting groups by ball milling to obtain the modified two-dimensional nanomaterial.

[0008] In some embodiments of the present disclosure, the mass ratio of the two-dimensional nanomaterial to the compound containing grafting groups is 1:(0.2 - 0.5).

[0009] In some embodiments of the present disclosure, the compound containing a graft group is selected from one or more of sodium 2-acrylamido-2-methylpropanesulfonate, 2-methacryloyloxyethyl phosphorylcholine, dimethyldiallylammonium chloride, and methacryloyloxyethyl trimethylammonium chloride.

[0010] As another aspect, the present disclosure provides an application of the above-mentioned modified two-dimensional nanomaterial in a polymer composite material.

[0011] As another aspect, the present disclosure provides a polymer composite material, comprising the above-mentioned modified two-dimensional nanomaterial and a polymer.

[0012] As another aspect, the present disclosure provides a preparation method of the above-mentioned polymer composite material, comprising: melt-blending the above-mentioned modified two-dimensional nanomaterial and the polymer to prepare a modified two-dimensional nanomaterial / polymer composite material.

[0013] In some embodiments of the present disclosure, the polymer comprises polyethylene and / or polyetheretherketone.

[0014] In some embodiments of the present disclosure, the mass ratio of the modified two-dimensional nanomaterial to the polymer is (1-5):(95-99); and / or, the temperature of the melt-blending is 200-350 °C.

[0015] The technical solution provided by the embodiments of the present disclosure has the following advantages: by grafting any one or a combination of at least two of -SO3-, -PO3- or -N + - groups on the surface of the two-dimensional nanomaterial, the hydrophilicity of the two-dimensional nanomaterial is improved, the hydrophilicity of the surface of the polymer matrix material is improved, its hydration effect is enhanced, and it is easier to form a water film under water lubrication conditions to achieve hydration lubrication, which helps to achieve the effect of reducing friction and wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present disclosure and, together with the specification, are used to explain the principles of the present disclosure.

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a comparative thermogravimetric analysis diagram of unmodified boron nitride and the modified boron nitride in Preparation Example 1, Preparation Example 2 and Comparative Example 1;

[0019] Figure 2 SEM comparison diagram of Preparation Example 1 of the present disclosure and unmodified BN;

[0020] Figure 3 EDS spectrum diagram of the modified BN in Preparation Example 1 of the present disclosure;

[0021] Figure 4 Result comparison diagram of friction tests of Application Examples 1-3 and Comparative Examples 2-4 of the present disclosure;

[0022] Figure 5 Comparison diagram of thermogravimetric curves of Preparation Example 4 of the present disclosure and unmodified molybdenum disulfide. Detailed implementation manners

[0023] In order to be able to more clearly understand the above-mentioned objects, features and advantages of the present disclosure, the solutions of the present disclosure will be further described below. It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other.

[0024] Many specific details are set forth in the following description in order to fully understand the present disclosure, but the present disclosure can also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present disclosure, rather than all of the embodiments.

[0025] According to an embodiment of the present disclosure, a modified two-dimensional nanomaterial is provided. The modified two-dimensional nanomaterial is a two-dimensional nanomaterial having grafting groups on its surface, and the grafting groups include any one or a combination of at least two of SO3-, -PO3- or -N + - groups.

[0026] The modified two-dimensional nanomaterial provided by the embodiment of the present disclosure is grafted with SO3-, -PO3- or -N + - groups on the surface of the two-dimensional nanomaterial, any one or a combination of at least two of which improves the hydrophilicity of the two-dimensional nanomaterial.

[0027] In some embodiments of the present disclosure, the two-dimensional nanomaterial is selected from one or more of nano-molybdenum disulfide, nano-boron nitride, and nano-graphene oxide.

[0028] According to an embodiment of the present disclosure, a preparation method of the above-mentioned modified two-dimensional nanomaterial is provided. The preparation method includes the following steps: reacting the two-dimensional nanomaterial with a compound containing grafting groups by ball milling to obtain the modified two-dimensional nanomaterial.

[0029] In some embodiments of the present disclosure, the mass ratio of the two-dimensional nanomaterial to the compound containing a grafting group is 1:(0.2 - 0.5). For example, any one of the mass ratios selected from 1:0.26, 1:0.31, 1:0.36, 1:0.43, 1:0.49.

[0030] In some embodiments of the present disclosure, the compound containing a grafting group is selected from one or more of sodium 2-acrylamido-2-methylpropanesulfonate, 2-methacryloyloxyethyl phosphorylcholine, dimethyldiallylammonium chloride, and methacryloyloxyethyl trimethylammonium chloride.

[0031] In some embodiments of the present disclosure, the compound containing a grafting group is an ionic monomer.

[0032] In some embodiments of the present disclosure, the preparation method of the modified two-dimensional nanomaterial includes: mixing the two-dimensional nanomaterial with the ionic monomer to prepare a premixed filler of the ionic monomer / two-dimensional nanomaterial; reacting the premixed filler by ball milling to prepare a composite slurry of the ionic monomer / two-dimensional nanomaterial; dispersing the composite slurry in an aqueous solution and performing dialysis to prepare the modified two-dimensional nanomaterial of the modified two-dimensional nanomaterial.

[0033] In some embodiments of the present disclosure, the ionic monomer is selected from one or more of sodium 2-acrylamido-2-methylpropanesulfonate, 2-methacryloyloxyethyl phosphorylcholine, dimethyldiallylammonium chloride, and methacryloyloxyethyl trimethylammonium chloride.

[0034] In some embodiments of the present disclosure, the preparation method of the modified two-dimensional nanomaterial specifically includes the following steps: (1) After adding the two-dimensional nanomaterial to a high-speed mixer, add the ionic monomer and premix for 30 min to obtain a premixed filler of the ionic monomer / two-dimensional nanomaterial; (2) Pour the premixed filler of the ionic monomer / two-dimensional nanomaterial in step (1) into a ball milling jar filled with ZrO2 balls, add a small amount of water (the mass of the added water is 10 - 20% of the total mass of the two-dimensional nanomaterial and the ionic monomer), place the ball milling jar in a ball mill with a ball milling speed of 200 - 1000 r / min for ball milling reaction. After ball milling for 4 - 24 h, naturally cool to room temperature and collect the product ionic monomer / two-dimensional filler composite slurry; (3) Disperse the ionic monomer / two-dimensional filler composite slurry obtained in step (2) in an aqueous solution, transfer it to a dialysis bag (cut-off molecular weight 4000 - 14000), place it in deionized water for dialysis for 7 days, change the water every 1 day, and finally freeze-dry to obtain the surface chemically modified two-dimensional nanomaterial.

[0035] According to an embodiment of the present disclosure, there is provided an application of the above-mentioned modified two-dimensional nanomaterial in a polymer composite material.

[0036] According to an embodiment of the present disclosure, a polymer composite material is provided, which includes the above-mentioned modified two-dimensional nanomaterial and a polymer.

[0037] According to an embodiment of the present disclosure, a method for preparing the above-mentioned polymer composite material is provided, including: melt-blending the above-mentioned modified two-dimensional nanomaterial and the polymer to prepare a modified two-dimensional nanomaterial / polymer composite material.

[0038] In some embodiments of the present disclosure, the polymer includes polyethylene and / or polyetheretherketone.

[0039] In some embodiments of the present disclosure, the mass ratio of the modified two-dimensional nanomaterial to the polymer is (1 to 5):(95 to 99). Preferably, the total mass of the modified two-dimensional nanomaterial and the polymer is 100 parts. For example, the mass ratio of the modified two-dimensional nanomaterial to the polymer is selected from any one of the mass ratios including 4.5:95.5, 3.5:96.5, 2.4:97.6, 1.8:98.2, 1.1:98.9; and / or, the temperature of the melt-blending is 200 to 350 °C. For example, the temperature is selected from any one of the temperatures including 231 °C, 242 °C, 268 °C, 298 °C, 316 °C, 328 °C, 349 °C.

[0040] In some embodiments of the present disclosure, a method for preparing a polymer composite material includes the following steps: in parts by mass, adding 1 to 5 parts of the modified two-dimensional nanomaterial and 95 to 99 parts of the polymer into a high-speed mixer for mixing, and then adding the mixture into a torque rheometer for internal mixing to obtain a composite material of the surface chemically modified two-dimensional nanomaterial / polymer. Among them, the torque of the torque rheometer is 20 to 60 r / min, the temperature is 200 to 350 °C, and the time is 15 min.

[0041] In some embodiments of the present disclosure, when the polymer is polyethylene, the torque is 40 to 60 r / min, the temperature is 200 to 220 °C, and the time is 15 min. For example, the temperature is selected from any one of the temperatures including 201 °C, 209 °C, 213 °C, 216 °C, 219 °C.

[0042] In some embodiments of the present disclosure, when the polymer is polyetheretherketone, the torque is 20 to 50 r / min, the temperature is 300 to 350 °C, and the time is 15 min. For example, the temperature is selected from any one of the temperatures including 301 °C, 319 °C, 328 °C, 339 °C, 348 °C.

[0043] Preparation Example 1

[0044] This preparation example provides a modified two-dimensional material with surface grafted ionic groups

[0045] The preparation raw materials are:

[0046] By mass fraction, it includes the following components: 1 part of boron nitride, 0.2 part of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and 0.015 part of water.

[0047] The preparation method includes the steps:

[0048] (1) After adding nano boron nitride to a high-speed mixer, add 2-acrylamido-2-methylpropanesulfonic acid sodium salt and premix for 30 min to obtain a 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride premixed filler.

[0049] (2) Pour the premixed material in step (1) into a ball milling tank filled with ZrO2 balls, add water, place the ball milling tank in a ball mill with a ball milling speed of 850 r / min for ball milling reaction. After ball milling for 10 h, naturally cool to room temperature and collect the product 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride composite slurry.

[0050] (3) Disperse the composite slurry in step (2) in an aqueous solution, transfer it to a dialysis bag (cut-off molecular weight 4000 - 14000), place it in deionized water for dialysis for 7 days, change the water every 1 day, and finally obtain a boron nitride nanomaterial with sulfonic acid groups on the surface by freeze drying.

[0051] Preparation Example 2

[0052] This preparation example provides a modified two-dimensional material with surface grafted ionic groups

[0053] The preparation raw materials are:

[0054] By mass fraction, it includes the following components: 1 part of boron nitride, 0.3 part of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and 0.015 part of water.

[0055] The preparation method includes the steps:

[0056] (1) After adding nano boron nitride to a high-speed mixer, add 2-acrylamido-2-methylpropanesulfonic acid sodium salt and premix for 30 min to obtain a 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride premixed filler.

[0057] (2) Pour the premixed material in step (1) into a ball milling tank filled with ZrO2 balls, add water, place the ball milling tank in a ball mill with a ball milling speed of 850 r / min for ball milling reaction. After ball milling for 10 h, naturally cool to room temperature and collect the product 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride composite slurry.

[0058] (3) Disperse the composite slurry from step (2) in an aqueous solution, transfer it into a dialysis bag (cut-off molecular weight 4000 - 14000), place it in deionized water for dialysis for 7 days, change the water every 1 day, and finally obtain the boron nitride nanomaterial with sulfonic acid groups on the surface by freeze-drying.

[0059] Preparation Example 3

[0060] This preparation example provides a modified two-dimensional material with ion groups grafted on the surface

[0061] The preparation raw materials are:

[0062] By mass fraction, it includes the following components: 1 part of boron nitride, 0.5 part of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and 0.015 part of water.

[0063] The preparation method includes steps:

[0064] (1) After adding nano boron nitride to a high-speed blender, add 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and premix for 30 min to obtain the 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride premixed filler;

[0065] (2) Pour the premixed material from step (1) into a ball milling tank filled with ZrO2 balls, add water, place the ball milling tank in a ball mill with a ball milling speed of 850 r / min for ball milling reaction. After ball milling for 10 h, naturally cool to room temperature, and collect the product 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride composite slurry;

[0066] (3) Disperse the above composite slurry in an aqueous solution, transfer it into a dialysis bag (cut-off molecular weight 4000 - 14000), place it in deionized water for dialysis for 7 days, change the water every 1 day, and finally obtain the boron nitride nanomaterial with sulfonic acid groups on the surface by freeze-drying.

[0067] Comparative Example 1

[0068] The preparation raw materials are:

[0069] By mass fraction, it includes the following components: 1 part of boron nitride, 0.7 part of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and 0.015 part of water.

[0070] The preparation method includes steps:

[0071] (1) After adding nano boron nitride to a high-speed blender, add 2-acrylamido-2-methylpropanesulfonic acid sodium salt, and premix for 30 min to obtain the 2-acrylamido-2-methylpropanesulfonic acid sodium salt / boron nitride premixed filler;

[0072] (2) Pour the premix in step (1) into a ball mill tank filled with ZrO2 balls, add water, place the ball mill tank in a ball mill with a ball milling speed of 850 r / min for ball milling reaction. After ball milling for 10 h, cool it naturally to room temperature, and collect the product 2-acrylamido-2-methylpropanesulfonic acid sodium / boron nitride composite slurry;

[0073] (3) Disperse the composite slurry in step (2) in an aqueous solution, transfer it to a dialysis bag (cut-off molecular weight 4000 - 14000), and place it in deionized water for dialysis for 7 days. Change the water every 1 day, and finally obtain boron nitride nanomaterials with sulfonic acid groups on the surface by freeze drying.

[0074] Testing and result analysis:

[0075] (1) Thermogravimetric analysis tests were carried out on unmodified boron nitride and the modified boron nitride in Preparation Example 1, Preparation Example 2, and Comparative Example 1. The test results are as Figure 1 shown.

[0076] From Figure 1 the thermogravimetric curve, it can be seen that the thermal weight loss of the modified boron nitride has increased significantly, which is due to the decomposition of the organic groups introduced on the surface of boron nitride. Compared with Preparation Example 1, in Preparation Example 2, due to the increase in the proportion of ionic monomers, the grafting content also increases. However, it can be seen from Comparative Example 1 that further increasing the proportion of ionic monomers does not lead to a continuous increase in the grafting content. Therefore, the final ratio of ionic monomers to boron nitride is selected to be 0.2 - 0.5.

[0077] (2) SEM spectrum tests were carried out on the modified BN in Preparation Example 1 and unmodified BN. The test results are as Figure 2 shown.

[0078] Figure 2 The SEM images of Preparation Example 1 and unmodified BN are shown. From Figure 2 it can be clearly seen that the surface of the modified BN is rougher, and there are some flocculent polymers attached to the surface. While the surface of unmodified BN is smoother.

[0079] (3) EDS energy spectrum analysis tests were carried out on the modified BN in Preparation Example 1. The test results are as Figure 3 shown.

[0080] Figure 3 The EDS energy spectrum image of the modified BN in Preparation Example 1 is shown. From Figure 3 it can be seen that there are obvious elements such as C, N, O, S, etc. on the surface of the modified BN, proving the success of grafting.

[0081] Application Example 1

[0082] One part of the boron nitride nanomaterial with sulfonic acid groups on the surface in Preparation Example 1 and 98 parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a modified boron nitride / ultra-high molecular weight polyethylene composite material.

[0083] Application Example 2

[0084] Three parts of the boron nitride nanomaterial with sulfonic acid groups on the surface in Preparation Example 1 and 98 parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a modified boron nitride / ultra-high molecular weight polyethylene composite material.

[0085] Application Example 3

[0086] Five parts of the boron nitride nanomaterial with sulfonic acid groups on the surface in Preparation Example 1 and 95 parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a modified boron nitride / ultra-high molecular weight polyethylene composite material.

[0087] Comparative Example 2

[0088] Seven parts of the boron nitride nanomaterial with sulfonic acid groups on the surface in Preparation Example 1 and 93 parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a modified boron nitride / ultra-high molecular weight polyethylene composite material.

[0089] Comparative Example 3

[0090] One hundred parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a pure ultra-high molecular weight polyethylene material.

[0091] Comparative Example 4

[0092] Three parts of nano boron nitride and 98 parts of ultra-high molecular weight polyethylene were added to a high-speed mixer for mixing, and then added to a torque rheometer for internal mixing. The torque was 50 r / min, the temperature was 205 °C, and the time was 15 min to obtain a boron nitride / ultra-high molecular weight polyethylene material.

[0093] Testing and Result Analysis:

[0094] The friction tests were carried out on Application Examples 1-3 and Comparative Examples 2-4 using an Rtec friction and wear tester. The test conditions were reciprocating tests with a load of 15 N, a frequency of 5 Hz, a test length of 6 mm, and a medium of 3% NaCl solution. The results are as Figure 4 shown.

[0095] From Figure 4 the comparison chart of the results of the friction tests, it can be seen that the friction curves of Application Examples 1-3 are significantly lower than those of Comparative Examples 2-4. At a test time of 2400 s, the friction coefficients of Application Examples 1, 2, and 3 are 0.052, 0.044, and 0.051 respectively. While the friction coefficients of Comparative Examples 2, 3, and 4 are 0.059, 0.066, and 0.058 respectively. In Comparative Example 2, due to the excessive addition amount of the modified boron nitride, the agglomeration of the filler instead causes a decrease in the mechanical properties of the material, thereby leading to an increase in the friction coefficient. Comparative Example 4 is unmodified boron nitride, and due to the poor compatibility between its surface and the matrix, the friction coefficient is also relatively large. And in Comparative Example 3, not only is the friction coefficient much higher than that of Application Examples 1-3, but also the curve fluctuates significantly. Obviously, due to the lack of the introduction of two-dimensional materials, the mechanical properties of the material are relatively poor, so the friction coefficient is also higher. Generally speaking, the friction coefficient of the sample with the modified boron nitride added is significantly reduced. On the one hand, the compatibility between the modified boron nitride and the polymer matrix is improved, enhancing the mechanical properties of the sample; on the other hand, the introduction of ionic functional groups improves the hydration effect of the polymer, achieving the effect of hydration lubrication. However, the introduction amount of the modified boron nitride needs to be within an appropriate range, otherwise the mechanical properties will also decrease due to the agglomeration of the filler, improving the friction performance.

[0096] Preparation Example 4

[0097] This preparation example provides a modified two-dimensional material with surface-grafted ionic groups

[0098] The preparation raw materials are:

[0099] By mass fraction, it includes the following components: 1 part of nano molybdenum disulfide, 0.4 part of 2-methacryloyloxyethyl phosphorylcholine, and 0.28 part of water.

[0100] The preparation method includes the steps:

[0101] (1) After adding nano molybdenum disulfide to a high-speed blender, add 2-methacryloyloxyethyl phosphorylcholine and premix for 30 min to obtain a 2-methacryloyloxyethyl phosphorylcholine / molybdenum disulfide premixed filler;

[0102] (2) Pour the premix in step (1) into a ball milling tank filled with ZrO2 balls, add water, place the ball milling tank in a ball mill with a ball milling speed of 900 r / min for ball milling reaction. After ball milling for 24 h, naturally cool to room temperature, and collect the 2-methacryloyloxyethyl phosphorylcholine / molybdenum disulfide composite slurry.

[0103] (3) Disperse the composite slurry in step (2) in an aqueous solution, transfer it to a dialysis bag (cut-off molecular weight 4000 - 14000), and place it in deionized water for dialysis for 7 days. Change the water every 1 day, and finally obtain the molybdenum disulfide material with phosphorylcholine on the surface by freeze drying.

[0104] Perform thermogravimetric analysis tests on Preparation Example 4 and unmodified molybdenum disulfide. The test results are as Figure 5 shown.

[0105] From Figure 5 the comparison chart of the thermogravimetric curves of Preparation Example 4 and unmodified molybdenum disulfide, it can be seen that the thermal weight loss of the modified molybdenum disulfide is significantly improved, which is due to the decomposition of the organic groups introduced on the surface of molybdenum disulfide.

[0106] Application Example 4

[0107] Add 2 parts of the surface-modified molybdenum disulfide material in Preparation Example 1 and 98 parts of polyetheretherketone to a high-speed mixer for mixing, and then add them to a torque rheometer for internal mixing. The torque is 40 r / min, the temperature is 330 °C, and the time is 15 min to obtain the modified molybdenum disulfide / polyetheretherketone composite material.

[0108] Application Example 5

[0109] Add 4 parts of the surface-modified molybdenum disulfide material in Preparation Example 1 and 96 parts of polyetheretherketone to a high-speed mixer for mixing, and then add them to a torque rheometer for internal mixing. The torque is 40 r / min, the temperature is 330 °C, and the time is 15 min to obtain the modified molybdenum disulfide / polyetheretherketone composite material.

[0110] Comparative Example 5

[0111] Add 2 parts of the unmodified molybdenum disulfide material and 98 parts of polyetheretherketone to a high-speed mixer for mixing, and then add them to a torque rheometer for internal mixing. The torque is 40 r / min, the temperature is 330 °C, and the time is 15 min to obtain the molybdenum disulfide / polyetheretherketone composite material.

[0112] Comparative Example 6

[0113] Add 100 parts of polyetheretherketone to a high-speed mixer for mixing, and then add them to a torque rheometer for internal mixing. The torque is 40 r / min, the temperature is 330 °C, and the time is 15 min to obtain pure polyetheretherketone.

[0114] Test and result analysis:

[0115] The friction tests were carried out on Application Examples 4 and 5 and Comparative Examples 5 and 6 using an Rtec friction and wear tester. The test conditions were reciprocating tests with a load of 15 N, a frequency of 5 Hz, a test length of 6 mm, and a medium of 3% NaCl solution. Among them, the friction coefficients of Examples 4 and 5 were 0.038 and 0.032 respectively, while the results of Comparative Examples 5 and 6 were 0.045 and 0.063 respectively. It can be seen that the modification of grafting ionic groups on the surface has a good effect on reducing the friction coefficient of polyether ether ketone.

[0116] In summary, the modified two-dimensional nanomaterials and their preparation methods provided by the embodiments of the present disclosure can improve the hydrophilicity of the surface of polymer materials and enhance their hydration effect by chemically grafting SO3−, -PO3−, -N + - groups on the surface of two-dimensional materials. Under water lubrication conditions, it is easier to form a water film to achieve hydration lubrication and reduce friction and wear. In the application of the modified two-dimensional nanomaterials provided by the embodiments of the present disclosure in polymer composites, there are a large number of ionic groups on the surface of the modified two-dimensional materials, which makes the modified two-dimensional materials have good compatibility with polymers, improves the interfacial interaction between the modified two-dimensional materials and the polymer matrix, and can simultaneously improve the mechanical properties and friction properties of polymers. In addition, the embodiments of the present invention are simple and feasible, highly operable, and can be mass-produced.

[0117] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0118] The above are only specific embodiments of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A modified two-dimensional nanomaterial, characterized in that, The modified two-dimensional nanomaterial is a two-dimensional nanomaterial with grafting groups on its surface, and the grafting groups include any one or a combination of at least two of SO3-, -PO3- or -N + - groups; The preparation method of the modified two-dimensional nanomaterial comprises the following steps: reacting the two-dimensional nanomaterial with a compound containing a grafting group by ball milling to obtain the modified two-dimensional nanomaterial; The two-dimensional nanomaterial is selected from one or more of nano molybdenum disulfide, nano boron nitride, and nano graphene oxide; The compound containing a grafting group is selected from one or both of sodium 2-acrylamido-2-methylpropanesulfonate and 2-methacryloyloxyethyl phosphorylcholine.

2. The preparation method of the modified two-dimensional nanomaterial according to claim 1, characterized in that, The preparation method comprises the following steps: Reacting the two-dimensional nanomaterial with a compound containing a grafting group by ball milling to obtain the modified two-dimensional nanomaterial.

3. According to the preparation method described in claim 2, characterized in that, The mass ratio of the two-dimensional nanomaterial to the compound containing a grafting group is 1:(0.2 - 0.5).

4. An application of the modified two-dimensional nanomaterial described in claim 1 in a polymer composite material.

5. A polymer composite material, characterized in that, Comprising: The modified two-dimensional nanomaterial described in claim 1 and a polymer.

6. A method for preparing the polymer composite material according to claim 5, characterized in that, Comprising: Melting and blending the modified two-dimensional nanomaterial described in claim 1 and a polymer to prepare a modified two-dimensional nanomaterial / polymer composite material.

7. According to the preparation method described in claim 6, characterized in that, The polymer comprises polyethylene and / or polyether ether ketone.

8. According to the preparation method described in claim 6 or 7, characterized in that, The mass ratio of the modified two-dimensional nanomaterial to the polymer is (1 - 5):(95 - 99); and / or, the temperature of melting and blending is 200 - 350 °C.

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