Molybdenum disulfide modified natural rubber composite material and preparation method thereof

Abstract

The invention discloses a molybdenum disulfide modified natural rubber composite material and a preparation method thereof. Natural biological polysaccharide glucomannan is adopted as a dispersing agent and a surface modifier, efficient stripping and stable dispersion (particle size distribution D90 is smaller than or equal to 2 microns, and the thickness is smaller than or equal to 100 nm) of molybdenum disulfide nanosheets are achieved through a sanding stripping process in a water-phase system, and the rubber master batch is prepared in combination with a flocculation forming process. A gulcomannan molecular layer coating structure is formed on the surface of the modified molybdenum disulfide, and the filler-matrix interfacial compatibility is improved through hydrogen-bond interaction and steric hindrance effect, so that compared with the contrast without the molybdenum disulfide, the tensile strength of the composite material is improved by 30% or above, the tearing strength is improved by 50% or above, and the wear resistance is improved by 20% or above (Akron wear is less than or equal to 0.281 cm < 3 >); the thermal decomposition temperature is increased by 11 DEG C or above, the rolling resistance is reduced by 20%-25%, and the wet skid resistance is improved by 8%-15%. The method adopts a water phase system, does not need an organic solvent, is simple in process, and is suitable for large-scale production of rubber products such as tire treads and conveying belts.

Description

Technical Field

[0001] The invention relates to the field of modified rubber fillers, and in particular to a preparation method of modified molybdenum disulfide and application thereof in natural rubber. Background Art

[0002] Rubber materials are one of the key materials indispensable in industry and national defense, and are widely used in automotive tires, medical devices, aerospace, chemical protection equipment, and other fields. Natural rubber is widely used in rubber products such as tires, tracks, and shock-absorbing seals due to its excellent properties at room temperature, such as high elasticity, low air permeability, and low rolling resistance. With the development of the automotive industry, higher requirements are placed on tire performance, which has also led to the exploration and application of new fillers. Molybdenum disulfide has a large specific surface area, high modulus, and high strength, which makes it highly reinforcing for rubber composites. In addition, the excellent lubricity, thermal stability, and low friction coefficient of molybdenum disulfide nanosheets make it possible to improve the wear resistance of tread rubber, enhance its high temperature resistance, and reduce rolling heat generation.

[0003] Because molybdenum disulfide particles are large and have a hydrophilic surface, they have poor compatibility with the rubber matrix and are prone to agglomeration in rubber, making it difficult to exert its reinforcing effect. Therefore, it needs to be surface modified. Currently, in the research of molybdenum disulfide and rubber composites, the exfoliation and surface functionalization of molybdenum disulfide mostly inevitably use organic solvents, which are easy to pollute the environment. In addition, the low exfoliation efficiency and high economic cost also limit its industrial application. Therefore, it is very meaningful to develop a green, efficient, easy-to-operate, and low-cost method for the exfoliation and modification of molybdenum disulfide nanosheets, and to successfully promote it to rubber industrial production. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of how to achieve green and efficient stripping of molybdenum disulfide, the poor dispersion performance of molybdenum disulfide in the rubber matrix, the weak interfacial compatibility with the rubber matrix, and the difficulty in improving the mechanical properties, wear resistance, and high temperature resistance of the rubber composite material, and to provide a molybdenum disulfide-modified natural rubber composite material and a preparation method thereof.

[0005] The technical solution for achieving the purpose of the present invention is:

[0006] A method for preparing a molybdenum disulfide modified natural rubber composite material comprises the following steps

[0007] (1) Preparing a modified molybdenum disulfide slurry: adding molybdenum disulfide to a glucomannan solution and mixing them evenly, and sand-milling the mixture to obtain a modified molybdenum disulfide slurry;

[0008] (2) Preparing a molybdenum disulfide modified natural rubber masterbatch: the modified molybdenum disulfide slurry prepared in step (1) is stirred and evenly mixed with natural rubber latex, and then flocculated with an acidic flocculant, and finally washed, sliced, and dried to obtain a molybdenum disulfide modified natural rubber masterbatch;

[0009] (3) Preparation of molybdenum disulfide modified natural rubber composite material: the molybdenum disulfide modified natural rubber masterbatch obtained in step (2) is mixed with a rubber additive, and after plasticizing, mixing and vulcanization, a molybdenum disulfide modified natural rubber composite material is obtained.

[0010] In step (1), the concentration of the glucomannan solution is 1-5 mg / mL; the glucomannan solution is prepared by mixing glucomannan powder with a fineness of 80-100 mesh, a molecular weight of 200,000-1.2 million Da, and a purity of ≥90% with deionized water at 70-100°C.

[0011] In step (1), the mass ratio of molybdenum disulfide to glucomannan is 10-40.

[0012] In step (1), the sanding speed is 1000-4000 r / min, the sanding time is 1-12 h, and the sanding temperature is 5-65°C.

[0013] In step (2), the mass ratio of the modified molybdenum disulfide to the dry rubber in the natural rubber latex is 0.02-0.1.

[0014] In step (2), the acidic flocculant is an aqueous solution of formic acid, acetic acid, sulfuric acid and the like, with a mass concentration of 5-15 wt%.

[0015] In step (2), the stirring speed is 100-800 r / min; and the drying temperature is 50-120°C.

[0016] In step (3), the rubber additives include one or more of a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a reinforcing agent, a filler, an antioxidant, a softener, and a scorch retarder.

[0017] In step (3), the plasticizing time is 1-4 min, the temperature is 30-70°C; the mixing time is 5-8 min, the temperature is 60-90°C; the vulcanization temperature is 140-150°C, the vulcanization pressure is 8-15 MPa, and the vulcanization time is 12-20 min.

[0018] The molybdenum disulfide-modified natural rubber composite material prepared by the above method includes a natural rubber matrix and molybdenum disulfide nanosheets dispersed therein, wherein the surface of the molybdenum disulfide nanosheets is coated with a glucomannan molecular layer; the particle size distribution D90 of the molybdenum disulfide nanosheets is ≤2 μm and the average thickness is ≤100 nm; and the mass content of molybdenum disulfide in the composite material is 2%-10% of the natural rubber.

[0019] The present application provides a molybdenum disulfide-modified natural rubber composite material and a preparation method thereof. The preparation method utilizes glucomannan, a natural biopolysaccharide, to exfoliate and surface-modify the molybdenum disulfide through sand milling, and then achieves good interfacial bonding with natural rubber through an emulsion blending method. The method sand mills a mixture of glucomannan and molybdenum disulfide in a sand mill. High-speed shear forces cause interlayer exfoliation of the molybdenum disulfide, reducing its lateral size. Simultaneously, the glucomannan molecular chains partially depolymerize, exposing acetyl groups that bind to sulfur vacancies in the sand-milled molybdenum disulfide nanosheets, coating the molybdenum disulfide surface with glucomannan. The modified molybdenum disulfide slurry is then mixed with natural rubber through an emulsion blending method to produce a masterbatch. Finally, a sample is obtained through mixing and vulcanization. This method not only improves the dispersion of molybdenum disulfide in the natural rubber matrix, but also forms physical crosslinks between the polar groups on the surface of glucomannan and the natural rubber molecular chains, enhancing interfacial bonding strength, and strengthening the mechanical properties, wear resistance, and high-temperature resistance of the rubber composite material, improving wet-skid resistance, and reducing rolling resistance. Specific advantages include:

[0020] (1) The present invention uses green and environmentally friendly glucomannan as the stripping medium and utilizes the sand milling process to achieve efficient stripping of molybdenum disulfide materials. During the sand milling process, glucomannan acts as a dispersant and compatibilizer and is coated on the surface of molybdenum disulfide, thereby changing the surface polarity of molybdenum disulfide, enhancing the interfacial bonding force with the rubber matrix, and improving the overall performance of the rubber composite material.

[0021] (2) Compared with the traditional method of chemically modifying molybdenum disulfide with coupling agents, this technology uses the natural bio-based material glucomannan as a modifier for the first time, avoiding solvent pollution and complex processes in chemical coupling agent treatment; in addition, this technology combines the sand grinding process with the viscosity of glucomannan, which not only achieves uniform exfoliation and dispersion of molybdenum disulfide, but also has the advantages of simple processing equipment and wide applicability, and is expected to be applied in industry.

[0022] (3) This technology adopts the emulsion blending method to avoid the problem of filler agglomeration in traditional dry mixing, increase the contact area between the molybdenum disulfide filler and the natural rubber matrix, and further improve the dispersion uniformity of the molybdenum disulfide filler.

[0023] (4) Existing technologies mostly focus on the application of coupling agent-modified molybdenum disulfide in general rubber, while this technology can optimize the interface bonding based on the specificity of natural rubber, such as high protein content and high viscosity, thereby improving its practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope image of glucomannan peeling off molybdenum disulfide nanosheets in Example 1;

[0025] Figure 2 This is a particle size curve of glucomannan-exfoliated molybdenum disulfide nanosheets in Example 1;

[0026] Figure 3 This is the infrared spectrum of the glucomannan-exfoliated molybdenum disulfide nanosheets in Example 1;

[0027] Figure 4 This is a scanning electron microscope image of modified molybdenum disulfide nanosheets dispersed in the rubber matrix in Example 1;

[0028] Figure 5 : The wear volume curves of the molybdenum disulfide modified natural rubber composite materials in Comparative Examples 1-2 and Examples 2-5;

[0029] Figure 6 are the mechanical property parameters of the molybdenum disulfide modified natural rubber composite materials in Comparative Examples 1-2 and Examples 2-5;

[0030] Figure 7 are the thermogravimetric parameters of the molybdenum disulfide modified natural rubber composite materials in Comparative Examples 1-2 and Examples 2-5;

[0031] Figure 8 These are the dynamic thermodynamic parameters of the molybdenum disulfide modified natural rubber composite materials in Comparative Examples 1-2 and Examples 2-5. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the present invention is not limited thereto.

[0033] In the following embodiments, the rubber additives used are specifically zinc oxide, stearic acid, antioxidant 4020, antioxidant RD, carbon black N330, aromatic oil, sulfur, accelerator DM, accelerator TMTD, and scorch retarder CTP.

[0034] Example 1

[0035] (1) Weigh 600 mg of glucomannan powder (glucomannan molecular weight range is 200,000-1.2 million Da), add 300 mL of deionized water at 70-100 °C, and stir at 500 r / min for 0.5 h to prepare 300 mL of glucomannan solution with a concentration of 2 mg / mL. Add 5-25 g of molybdenum disulfide powder to the above glucomannan solution and stir and disperse at 500 r / min for 2 h. Then pour the dispersion into the sand mill material tank for circular sand milling at a speed of 2500 r / min, a zirconium bead size of 0.15-0.35 mm, a zirconium bead filling amount of 280-380 g, and a sand milling time of 4-5 h. Take out the sample after sand milling.

[0036] (2) Place the sample in step (1) in a refrigerator for 6-10 hours, take it out and centrifuge it at 8000-10000 r / min for 20 minutes, and place the lower precipitate in a vacuum oven at 60-70℃ and dry it for 12-20 hours to obtain molybdenum disulfide nanosheets.

[0037] (3) Figure 1 This is a scanning electron micrograph of molybdenum disulfide sand-milled with a glucomannan solution. As can be seen from the image, the original molybdenum disulfide particles are larger than 8 μm in the lateral direction and exhibit significant agglomeration. After sand-milling with a 2 mg / mL glucomannan solution, the particles are reduced to less than 2 μm in the lateral direction, and their dispersion uniformity is significantly improved.

[0038] (4) Figure 2 The following is a particle size curve of molybdenum disulfide sand-ground with a glucomannan solution. As can be seen from the figure, the overall particle size distribution of molybdenum disulfide sand-ground with a 2 mg / mL glucomannan solution shifts toward the submicron level, with the Dv50 of molybdenum disulfide decreasing from the original 9.95 μm to 0.92 μm after sand-grinding.

[0039] (5) Figure 3 This is the infrared spectrum of molybdenum disulfide sand-milled with glucomannan solution. As can be seen from the figure, the hydroxyl and carboxyl groups on the surface of the molybdenum disulfide are reduced after sand-milling, and an acetyl group peak appears, indicating that the glucomannan is coated on the molybdenum disulfide surface.

[0040] (6) Figure 4 This is a scanning electron microscope image of the molybdenum disulfide filler sand-ground with glucomannan solution and added to the rubber matrix. It can be seen from the figure that the dispersion of the molybdenum disulfide filler in the rubber matrix after sanding has been greatly improved, and the interfacial compatibility between the filler and the rubber matrix has been improved.

[0041] Comparative Example 1

[0042] (1) Weigh 390 g of natural rubber latex, add 100 mL of deionized water, stir and pre-disperse for 1 h, and flocculate with 10 wt% formic acid solution to obtain a masterbatch, which is then soaked, sliced, and dried to obtain pure natural rubber masterbatch.

[0043] (2) The natural rubber masterbatch was plasticized at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, standard specimens were cut and tested. The basic rubber processing formula was as follows: natural rubber 100 parts; zinc oxide 5 parts; stearic acid 2 parts; antioxidant 4020 2 parts, antioxidant RD 1.5 parts, carbon black N330 45 parts, aromatic oil 1.5 parts, sulfur 2 parts; accelerator DM 1 part; accelerator TMTD 0.1 part; scorch retarder CTP 0.5 part.

[0044] (3) According to the mechanical properties test results (see Figure 6 ) It can be seen from the data that the tensile strength of pure natural rubber is 16.56 MPa, the elongation at break is 468.7%, the tear strength is 30.66 N / mm, and the Shore hardness is 53.9 A.

[0045] (4) According to the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of pure natural rubber is 339.9℃. According to the wear resistance test results (see Figure 5 ) It can be seen that the Akron wear volume of pure natural rubber is 0.362 cm 3 ; According to the dynamic thermal mechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material at 0℃ and 60℃ are 0.075 and 0.038, respectively.

[0046] Comparative Example 2

[0047] (1) Take 11.5 g of molybdenum disulfide powder, add it to deionized water, and stir it at 55 °C for 1 h to pre-disperse it.

[0048] (2) Weigh 380 g of natural rubber latex and use the molybdenum disulfide solution as a reinforcing filler in an emulsion blending manner. The flocculated masterbatch is plasticized at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, it is cut into standard samples for corresponding testing. The basic formula for rubber processing is: 100 parts natural rubber; 5 parts zinc oxide; 2 parts stearic acid; 2 parts antioxidant 4020, 1.5 parts antioxidant RD, 45 parts carbon black N330, 1.5 parts aromatic oil, 2 parts sulfur; 1 part accelerator DM; 0.1 part accelerator TMTD; 0.5 parts anti-scorch agent CTP; 5 parts molybdenum disulfide.

[0049] (3) Compared with pure natural rubber, the mechanical properties test results (see Figure 6 ) It can be seen that the tensile strength of natural rubber with the addition of 5 parts of molybdenum disulfide increases by 13.5%; the elongation at break increases by 2.4%; the tear strength increases by 11.8%; and the Shore hardness increases by 3.8%.

[0050] (4) Compared with pure natural rubber, the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of natural rubber with 5 parts of molybdenum disulfide increased by 2.7 ° C; from the wear resistance test (see Figure 5 ) It can be seen that the Akron wear volume of natural rubber with 5 parts of molybdenum disulfide is reduced by 9.0%; from the dynamic thermal mechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material increases by 0.001 at 0°C, and decreases by 0.002 at 60°C.

[0051] Example 2

[0052] (1) Take 600 mg of glucomannan powder, the molecular weight of which is in the range of 200,000-1.2 million Da, add 300 mL of deionized water at 70-100 °C and stir for 10 min. Then take 5.75 g of molybdenum disulfide powder and add it to the glucomannan solution. Stir and pre-disperse it at 55 °C for 1 h. Finally, put it into the sand mill material tank for cyclic sand grinding at a speed of 2500 r / min, the zirconium bead size is 0.15-0.35 mm, the zirconium bead filling amount is 280-380 g, the sand grinding time is 4-5 h, and the sample is taken out after sand grinding.

[0053] (2) Weigh 385 g of natural rubber latex and use 5.75 g of modified molybdenum disulfide slurry prepared in Example 1 as a natural rubber reinforcing filler in an emulsion blending manner. The flocculated masterbatch is plasticized at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, standard samples are cut and tested accordingly. The basic formula for rubber processing is 100 parts of natural rubber; 5 parts of zinc oxide; 2 parts of stearic acid; 2 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 45 parts of carbon black N330, 1.5 parts of aromatic oil, 2 parts of sulfur; 1 part of accelerator DM; 0.1 part of accelerator TMTD; 0.5 parts of anti-scorch agent CTP; and 2.5 parts of modified molybdenum disulfide.

[0054] (3) Compared with pure natural rubber, the mechanical properties test results (see Figure 6 ) It can be seen that the tensile strength of natural rubber with the addition of 2.5 parts of modified molybdenum disulfide increased by 16.2%; the elongation at break increased by 3.4%; the tear strength increased by 21.7%; and the Shore hardness increased by 6.6%.

[0055] (4) Compared with pure natural rubber, the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of natural rubber with the addition of 2.5 parts of modified molybdenum disulfide increases by 6.3°C; from the wear resistance test (see Figure 5 ) It can be seen that the Akron wear volume of natural rubber with 2.5 parts of modified molybdenum disulfide is reduced by 12.7%; from the dynamic thermomechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material decreases by 0.001 and 0.006 at 0℃ and 60℃, respectively.

[0056] Example 3

[0057] (1) Take 600 mg of glucomannan powder, the molecular weight of which is in the range of 200,000-1.2 million Da, add 300 mL of deionized water at 70-100 °C and stir for 10 min. Then take 11.5 g of molybdenum disulfide powder and add it to the glucomannan solution. Stir and pre-disperse it at 50 °C for 1 h. Finally, put it into the sand mill material tank for cyclic sand grinding at a speed of 2500 r / min, the zirconium bead size is 0.15-0.35 mm, the zirconium bead filling amount is 280-380 g, the sand grinding time is 4-5 h, and the sample is taken out after sand grinding.

[0058] (2) Weigh 380 g of natural rubber latex and use 11.5 g of the modified molybdenum disulfide slurry prepared in Example 1 above as a natural rubber reinforcing filler in an emulsion blending manner. The flocculated masterbatch is plasticized at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, standard samples are cut and tested accordingly. The basic formula for rubber processing is 100 parts of natural rubber; 5 parts of zinc oxide; 2 parts of stearic acid; 2 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 45 parts of carbon black N330, 1.5 parts of aromatic oil, 2 parts of sulfur; 1 part of accelerator DM; 0.1 part of accelerator TMTD; 0.5 parts of anti-scorch agent CTP; and 5 parts of modified molybdenum disulfide.

[0059] (3) Compared with pure natural rubber, the mechanical properties test results (see Figure 6 ) It can be seen that the tensile strength of natural rubber with the addition of 5 parts of modified molybdenum disulfide increases by 30.3%; the elongation at break increases by 8.1%; the tear strength increases by 39.1%; and the Shore hardness increases by 22.3%.

[0060] (4) Compared with pure natural rubber, the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of natural rubber with the addition of 5 parts of modified molybdenum disulfide increased by 7.9 ° C; from the wear resistance test (see Figure 5 ) It can be seen that the Akron wear volume of natural rubber with 5 parts of modified molybdenum disulfide is reduced by 22.3%; from the dynamic thermomechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material at 0℃ and 60℃ increases and decreases by 0.004, respectively.

[0061] Example 4

[0062] (1) Take 600 mg of glucomannan powder, the molecular weight of which is in the range of 200,000-1.2 million Da, add 300 mL of deionized water at 70-100 °C and stir for 10 min. Then take 16.1 g of molybdenum disulfide powder and add it to the glucomannan solution. Stir and pre-disperse it at 50 °C for 1 h. Finally, put it into the sand mill material tank for cyclic sand grinding at a speed of 2500 r / min, the zirconium bead size is 0.15-0.35 mm, the zirconium bead filling amount is 280-380 g, the sand grinding time is 4-5 h, and the sample is taken out after sand grinding.

[0063] (2) Weigh 375 g of natural rubber latex and use 16.1 g of the modified molybdenum disulfide slurry prepared in Example 1 above as a natural rubber reinforcing filler in an emulsion blending manner. The flocculated masterbatch is masticated at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, standard samples are cut and tested accordingly. The basic formula for rubber processing is: 100 parts of natural rubber; 5 parts of zinc oxide; 2 parts of stearic acid; 2 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 45 parts of carbon black N330, 1.5 parts of aromatic oil, 2 parts of sulfur; 1 part of accelerator DM; 0.1 part of accelerator TMTD; 0.5 parts of anti-scorch agent CTP; and 7 parts of modified molybdenum disulfide.

[0064] (3) Compared with pure natural rubber, the mechanical properties test results (see Figure 6 ) It can be seen that the tensile strength of natural rubber with the addition of 7 parts of modified molybdenum disulfide increased by 60.0%; the elongation at break increased by 7.8%; the tear strength increased by 56.4%; and the Shore hardness increased by 28.7%.

[0065] (4) Compared with pure natural rubber, the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of natural rubber with 7 parts of modified molybdenum disulfide increased by 11.3 ° C; from the wear resistance test (see Figure 5 ) It can be seen that the Akron wear volume of natural rubber with 7 parts of modified molybdenum disulfide is reduced by 14.6%; from the dynamic thermomechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material at 0℃ and 60℃ increases by 0.007 and decreases by 0.009, respectively.

[0066] Example 5

[0067] (1) Take 600 mg of glucomannan powder, the molecular weight of which is in the range of 200,000-1.2 million Da, add 300 mL of deionized water at 70-100 °C and stir for 10 min. Then take 20.7 g of molybdenum disulfide powder and add it to the glucomannan solution. Stir and pre-disperse it at 50 °C for 1 h. Finally, put it into the sand mill material tank for cyclic sand grinding at a speed of 2500 r / min, the zirconium bead size is 0.15-0.35 mm, the zirconium bead filling amount is 280-380 g, the sand grinding time is 4-5 h, and the sample is taken out after sand grinding.

[0068] (2) Weigh 370 g of natural rubber latex and use 20.7 g of the modified molybdenum disulfide slurry prepared in Example 1 above as a natural rubber reinforcing filler in an emulsion blending manner. The flocculated masterbatch is plasticized at 30-70°C for 1-4 min, mixed at 60-90°C for 5-8 min, and vulcanized at 140-150°C and 8-15 MPa for 12-20 min. Finally, it is cut into standard samples for corresponding testing. The basic formula for rubber processing is: 100 parts of natural rubber; 5 parts of zinc oxide; 2 parts of stearic acid; 2 parts of antioxidant 4020, 1.5 parts of antioxidant RD, 45 parts of carbon black N330, 1.5 parts of aromatic oil, 2 parts of sulfur; 1 part of accelerator DM; 0.1 part of accelerator TMTD; 0.5 parts of anti-scorch agent CTP; 9 parts of modified molybdenum disulfide.

[0069] (3) Compared with pure natural rubber, the mechanical properties test results (see Figure 6 ) It can be seen that the tensile strength of natural rubber with the addition of 9 parts of modified molybdenum disulfide increased by 26.7%; the elongation at break increased by 2.1%; the tear strength increased by 48.9%; and the Shore hardness increased by 27.2%.

[0070] (4) Compared with pure natural rubber, the thermogravimetric test results (see Figure 7 ) It can be seen that the thermal decomposition temperature of natural rubber with 9 parts of modified molybdenum disulfide increased by 5.4 ° C; from the wear resistance test (see Figure 5 ) It can be seen that the Akron wear volume of natural rubber with 9 parts of modified molybdenum disulfide is reduced by 1.7%; from the dynamic thermal mechanical properties test results (see Figure 8 ) It can be concluded that the Tan δ of the composite material at 0℃ and 60℃ remains unchanged and decreases by 0.006 respectively.

[0071] Comparative Examples 1-2 and Examples 2-5 show that the optimal reinforcement effect is achieved when the modified molybdenum disulfide dosage is 7 parts. This is because the appropriate amount of modified molybdenum disulfide nanosheets not only uniformly disperses within the rubber matrix but also provides a stronger interfacial bond with the rubber matrix. When the rubber matrix is ​​subjected to external forces, they effectively prevent crack propagation, improving mechanical properties. During friction, they form a lubricating film on the rubber matrix surface, improving wear resistance. During heating, they form a dense nanoscale barrier network, effectively slowing heat transfer into the rubber matrix and enhancing heat resistance.

Claims

1. A method for preparing a molybdenum disulfide modified natural rubber composite material, characterized in that: Includes the following steps (1) Preparing a modified molybdenum disulfide slurry: adding molybdenum disulfide to a glucomannan solution and mixing them evenly, and sand-milling the mixture to obtain a modified molybdenum disulfide slurry; (2) Preparing a molybdenum disulfide modified natural rubber masterbatch: the modified molybdenum disulfide slurry prepared in step (1) is stirred and evenly mixed with natural rubber latex, and then flocculated with an acidic flocculant, and finally washed, sliced, and dried to obtain a molybdenum disulfide modified natural rubber masterbatch; (3) Preparation of molybdenum disulfide modified natural rubber composite material: the molybdenum disulfide modified natural rubber masterbatch obtained in step (2) is mixed with a rubber additive, and after plasticizing, mixing and vulcanization, a molybdenum disulfide modified natural rubber composite material is obtained.

2. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, wherein: In step (1), the concentration of the glucomannan solution is 1-5 mg / mL.

3. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, wherein: In step (1), the mass ratio of molybdenum disulfide to glucomannan is 10-40.

4. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, wherein: In step (1), the sanding speed is 1000-4000 r / min, the sanding time is 1-12 h, and the sanding temperature is 5-65°C.

5. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, wherein: In step (2), the mass ratio of the modified molybdenum disulfide to the dry rubber in the natural rubber latex is 0.02-0.

1.

6. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, wherein: In step (2), the acidic flocculant is an aqueous solution of formic acid, acetic acid, and sulfuric acid reagents, and its mass concentration is 5-15wt%.

7. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, characterized in that: In step (2), the stirring speed is 100-800 r / min; and the drying temperature is 50-120°C.

8. The method for preparing a molybdenum disulfide modified natural rubber composite material according to claim 1, characterized in that: In step (3), the rubber additives include one or more of a vulcanizing agent, a vulcanization accelerator, a vulcanization activator, a reinforcing agent, a filler, an antioxidant, a softener, and a scorch retarder.

9. A molybdenum disulfide modified natural rubber composite material prepared by the method according to any one of claims 1 to 8, characterized in that: The composite material comprises a natural rubber matrix and molybdenum disulfide nanosheets dispersed therein, wherein the surface of the molybdenum disulfide nanosheets is coated with a glucomannan molecular layer; the particle size distribution D90 of the molybdenum disulfide nanosheets is ≤2 μm, and the average thickness is ≤100 nm; and the mass content of molybdenum disulfide in the composite material is 2%-10% of that of the natural rubber.

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