High wear-resistant nano-filler modified rubber material and preparation method thereof

Abstract

The application discloses a kind of high wear-resistant nano filler modified rubber material and preparation method thereof, belong to the technical field of rubber material modification.The water-soluble polyacrylic acid micelle is used as template, the hydrolysis rate of tetraethyl orthosilicate is controlled by controlling the amount of ammonia, and hollow SiO2 nanoparticles with porous shell and stable structure are prepared;Then modified by PEG-PLA block copolymer and silane coupling agent KH550, the particle dispersion and compatibility are improved.The modified porous hollow SiO2 particles are mixed with styrene-butadiene rubber slurry and milled, and the modified rubber material is obtained by vulcanization molding.The application improves the wear resistance and tensile strength of rubber, while maintaining good elasticity and elongation at break, achieving high strength, high wear resistance and high toughness, and the process is mild and controllable.

Description

Technical Field

[0001] This invention belongs to the field of rubber material modification technology, specifically relating to a high wear-resistant nanofiller modified rubber material and its preparation method. Background Technology

[0002] Rubber materials, due to their excellent elasticity, flexibility, and fatigue resistance, are widely used in industrial fields such as automobiles, machinery, and rail transportation. However, ordinary rubber materials have low surface hardness and poor wear resistance, making them prone to wear, aging, and cracking under long-term friction and reciprocating motion conditions. This significantly shortens the service life of products and limits their application in high-load, high-friction scenarios. Currently, the industry typically modifies rubber by adding nano-inorganic fillers (such as nano-SiO2, carbon black, and nano-TiO2). By leveraging the high strength and high hardness of inorganic nanoparticles, the wear resistance and mechanical strength of rubber can be improved.

[0003] However, there are some problems with directly filling rubber with traditional inorganic particles: First, nanoparticles are prone to agglomeration and uneven dispersion in the rubber matrix, which can easily form stress concentration points and reduce the mechanical properties of the material. Second, inorganic particles have poor interfacial compatibility and weak bonding with the rubber matrix, and the particles are prone to slippage and detachment under stress, resulting in poor reinforcement and wear resistance. Third, solid inorganic fillers have high density and require a high addition amount to achieve the reinforcement effect, which can lead to a decrease in rubber elasticity and toughness, an increase in brittleness, and a deterioration in processing performance.

[0004] While existing technologies have made some improvements through surface modification and blending process optimization, they have failed to fundamentally solve the inherent defects of solid inorganic particles, making it difficult to simultaneously achieve wear resistance, strength, and toughness. Therefore, there is an urgent need to develop a novel filler structure and corresponding rubber modification methods to improve wear resistance while ensuring good comprehensive mechanical and processing properties of the rubber. Summary of the Invention

[0005] This invention provides a highly wear-resistant nanofiller-modified rubber material and its preparation method. Using water-soluble micelles as a template, the hydrolysis rate of TEOS is controlled by adjusting the amount of ammonia to prepare porous hollow SiO2 nanoparticles with a porous shell and stable structure. Then, PEG-PLA block copolymers and silane coupling agents are used for synergistic modification. When blended with rubber slurry, the slurry components can enter the internal cavity of porous hollow SiO2 to form an interlocking composite structure. This reduces the proportion of inorganic fillers and avoids particle agglomeration, while synergistically improving the wear resistance and mechanical toughness of the rubber material. This solves the problems of filler agglomeration, performance imbalance, and poor wear resistance in existing nanofiller-modified rubber technologies.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for preparing a highly wear-resistant nanofiller-modified rubber material includes the following steps: S1. Preparation of water-soluble micelle template: Dissolve 0.3-0.5 parts of polyacrylic acid (PAA, Mv=3000) in 5-6 parts of 25% ammonia water by mass, and then add it dropwise to 100-120 parts of anhydrous ethanol to obtain micelle solution. S2. Dissolve 2-2.4 parts of tetraethyl orthosilicate in 10-12 parts of anhydrous ethanol, and then slowly add it dropwise to the micelle solution prepared in step S1. React at 30 degrees Celsius for 6-8 hours. After the reaction is completed, remove the PAA template by centrifugation and washing with water to obtain porous hollow SiO2 particles. S3. Add 15-20 parts of anhydrous ethanol to the porous hollow SiO2 particles in step S2, and then add 0.3-0.5 parts of silane coupling agent KH550 to prepare solution A; add 0.6-0.8 parts of PEG-PLA block copolymer to 15-20 parts of ethanol solution and stir to prepare a uniform mixed solution; then add the mixed solution to solution A and stir for 2-3 hours to obtain a modified porous hollow SiO2 particle dispersion.

[0007] S4. Preparation of rubber slurry: By mass, add 50 parts of styrene-butadiene rubber, 1-1.2 parts of zinc oxide, 0.5-1 parts of stearic acid, 0.4-0.6 parts of accelerator CZ, and 0.8-1.2 parts of sulfur to a mixer and mix for 15-20 minutes at 80-90℃ and 40-50 r / min to obtain a uniformly mixed rubber slurry.

[0008] S5. Composite Modification and Molding: Add 40-50 parts of the porous hollow SiO2 particle dispersion modified in step S3 to the rubber slurry, mix at 90-100℃ for 60-80 minutes, remove anhydrous ethanol to form a composite slurry; place the composite slurry into a mold, vulcanize at 160-170℃ and 10-12MPa for 25-30 minutes, and cool naturally to room temperature to obtain a high wear-resistant nanofiller modified rubber material.

[0009] Micellar templates were prepared using water-soluble PAA. Then, by increasing the amount of ammonia added and conditionally catalyzing the reaction rate, tetraethyl orthosilicate was rapidly deposited on the micelle surface. Due to the fast reaction rate, the deposited SiO2 shell was uneven, leaving pores. After removing the template by washing with water, a porous shell and hollow interior SiO2 structure was formed, which both reduced the proportion of inorganic phase and provided space for rubber molecules to penetrate.

[0010] The PEG-PLA block copolymer is synergistically modified with a silane coupling agent, resulting in more uniform mixing in the rubber slurry. Furthermore, the slurry penetrates the hollow cavity, achieving high wear resistance and strength despite low inorganic content, while maintaining rubber toughness.

[0011] The advantages of this invention compared to the prior art are: (1) Prepare SiO2 nanofillers with porous shells and hollow interiors. By adjusting the amount of ammonia water, control the TEOS hydrolysis deposition rate, significantly reduce the overall density of inorganic fillers, reduce the proportion of inorganic phase in rubber materials, and effectively avoid the problem of decreased rubber elasticity and increased brittleness caused by excessive filler addition.

[0012] (2) The PEG-PLA block copolymer and silane coupling agent KH550 were used for synergistic modification to improve the problem of easy agglomeration of nano-SiO2 particles, ensure that the filler is uniformly dispersed in the rubber matrix, and improve the compatibility between porous hollow SiO2 particles and rubber matrix.

[0013] (3) Compared with pure rubber substrate, the modified rubber material prepared by the present invention has significantly improved wear resistance, and the surface scratches are shallower and the roughness is lower after wear. Compared with dense shell SiO2 particle modified rubber, the product of the present invention maintains higher tensile strength while the elongation at break is not significantly reduced, achieving a unity of high strength, high wear resistance and high toughness, and has better comprehensive mechanical properties. Attached Figure Description

[0014] Figure 1 (a) and Figure 1 (b) in the figure are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the porous hollow SiO2 particles prepared in Example 1, respectively. Figure 2 TEM image of SiO2 particles prepared for Comparative Example 2; Figure 3 The Tyndall effect diagram for PAA micelle solutions; Figure 4 The surface morphology of rubber samples from Example 2, Comparative Example 1, and Comparative Example 2 after abrasion resistance testing; Figure 5 Atomic force microscopy (AFM) images of the samples from Example 2, Comparative Example 1, and Comparative Example 2 after abrasion resistance tests; Figure 6 The stress-strain curves are for the samples of Example 2, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1 Raw material ratio (parts by weight) S1: 0.3 parts of polyacrylic acid (PAA, Mv=3000), 5 parts of 25% ammonia water, and 100 parts of anhydrous ethanol; S2: 2 parts tetraethyl orthosilicate (TEOS), 10 parts anhydrous ethanol; S3: Porous hollow SiO2 particles, 15 parts anhydrous ethanol, 0.3 parts silane coupling agent KH550, 0.6 parts PEG-PLA block copolymer, and 15 parts ethanol solution. S4: 50 parts styrene-butadiene rubber, 1 part zinc oxide, 0.5 parts stearic acid, 0.4 parts accelerator CZ, and 0.8 parts sulfur; S5: 40 parts of modified porous hollow SiO2 particle dispersion.

[0017] Preparation steps S1. Preparation of water-soluble micelle template: 0.3 parts of polyacrylic acid (PAA, Mv=3000) were completely dissolved in 5 parts of 25% ammonia water and stirred thoroughly until the solution was transparent. Then, it was slowly added dropwise to 100 parts of anhydrous ethanol and stirred continuously for 30 minutes to obtain a stable and uniform water-soluble micelle solution.

[0018] S2. Preparation of porous hollow SiO2 particles: Dissolve 2 parts of tetraethyl orthosilicate in 10 parts of anhydrous ethanol, stir and mix well, and then slowly add it dropwise to the above micelle solution. After the addition is complete, place it in a constant temperature water bath at 30℃ for 6 hours. After the reaction is completed, centrifuge at 8000 r / min for 15 min, collect the solid product, wash it repeatedly with deionized water 3 times to completely remove the PAA template, and then vacuum dry it to obtain porous hollow SiO2 particles.

[0019] S3. Synergistic modification treatment: Add the dried porous hollow SiO2 particles to 15 parts of anhydrous ethanol, ultrasonically disperse for 20 min until uniform, then add 0.3 parts of KH550 and stir to prepare solution A; add 0.6 parts of PEG-PLA block copolymer to 15 parts of ethanol solution, stir in a 40℃ water bath for 40 min to form a transparent mixed solution; slowly add the mixed solution to solution A, and continue stirring at room temperature for 2 h to obtain a well-dispersed modified porous hollow SiO2 particle dispersion.

[0020] S4. Preparation of rubber slurry: Add 50 parts of styrene-butadiene rubber, 1 part of zinc oxide, 0.5 parts of stearic acid, 0.4 parts of accelerator CZ and 0.8 parts of sulfur to a mixer, set the temperature to 80℃ and the speed to 40r / min, and mix for 15min to obtain a uniformly mixed rubber slurry without lumps.

[0021] S5. Composite Modification and Molding: Take 40 parts of modified porous hollow SiO2 particle dispersion and add it to the rubber slurry. Heat to 90℃ and knead at 40r / min for 60min. During this period, evaporate anhydrous ethanol to form a composite slurry. Transfer the composite slurry into a stainless steel mold and vulcanize at 160℃ and 10MPa for 25min. Let it cool naturally to room temperature. After demolding, obtain a high wear-resistant nanofiller modified rubber material.

[0022] Example 2 Raw material ratio (parts by weight) S1: 0.4 parts of polyacrylic acid (PAA, Mv=3000), 5.5 parts of 25% ammonia water, and 110 parts of anhydrous ethanol; S2: 2.2 parts tetraethyl orthosilicate (TEOS), 11 parts anhydrous ethanol; S3: Porous hollow SiO2 particles, 18 parts anhydrous ethanol, 0.4 parts silane coupling agent KH550, 0.7 parts PEG-PLA block copolymer, and 18 parts ethanol solution; S4: 50 parts styrene-butadiene rubber, 1.1 parts zinc oxide, 0.8 parts stearic acid, 0.5 parts accelerator CZ, and 1.0 part sulfur; S5: 45 parts of modified porous hollow SiO2 particle dispersion.

[0023] Preparation steps S1. Preparation of water-soluble micelle template: Dissolve 0.4 parts of polyacrylic acid (PAA, Mv=3000) in 5.5 parts of 25% ammonia water, stir to dissolve, and then add dropwise to 110 parts of anhydrous ethanol. Stir for 40 min to obtain a water-soluble micelle solution.

[0024] S2. Preparation of porous hollow SiO2 particles: 2.2 parts of TEOS were dissolved in 11 parts of anhydrous ethanol and added dropwise to the micelle solution. The mixture was then reacted in a constant temperature water bath at 30°C for 7 hours. After centrifugation and washing with deionized water 4 times, the mixture was dried to obtain porous hollow SiO2 particles.

[0025] S3. Synergistic modification treatment: SiO2 particles were added to 18 parts of anhydrous ethanol and ultrasonically dispersed for 30 min. 0.4 parts of KH550 were added to prepare solution A. 0.7 parts of PEG-PLA were dissolved in 18 parts of ethanol solution and stirred in a water bath at 45℃ for 50 min to obtain a mixed solution. After mixing, the mixture was stirred at room temperature for 2.5 h to obtain a modified particle dispersion.

[0026] S4. Preparation of rubber slurry: 50 parts of styrene-butadiene rubber are mixed with 1.1 parts of zinc oxide, 0.8 parts of stearic acid, 0.5 parts of accelerator CZ and 1.0 parts of sulfur, and mixed at 85℃ and 45r / min for 18min to obtain a uniform rubber slurry.

[0027] S5. Composite modification and molding: 45 parts of modified particle dispersion were added to rubber slurry and mixed at 95℃ and 45r / min for 70min. After removing ethanol, a composite slurry was formed. The mixture was vulcanized at 165℃ and 11MPa for 28min and then cooled and demolded to obtain a high wear-resistant modified rubber material.

[0028] Example 3 Raw material ratio (parts by weight) S1: 0.5 parts of polyacrylic acid (PAA, Mv=3000), 6 parts of 25% ammonia water, and 120 parts of anhydrous ethanol; S2: 2.4 parts tetraethyl orthosilicate (TEOS), 12 parts anhydrous ethanol; S3: Porous hollow SiO2 particles, 20 parts anhydrous ethanol, 0.5 parts silane coupling agent KH550, 0.8 parts PEG-PLA block copolymer, and 20 parts ethanol solution; S4: 50 parts styrene-butadiene rubber, 1.2 parts zinc oxide, 1 part stearic acid, 0.6 parts accelerator CZ, and 1.2 parts sulfur; S5: 50 parts of modified porous hollow SiO2 particle dispersion.

[0029] Preparation steps S1. Preparation of water-soluble micelle template: 0.5 parts of polyacrylic acid were dissolved in 6 parts of 25% ammonia water, stirred evenly, and then added dropwise to 120 parts of anhydrous ethanol. The mixture was stirred continuously for 50 min to obtain a stable micelle solution.

[0030] S2. Preparation of porous hollow SiO2 particles: 2.4 parts of TEOS were dissolved in 12 parts of anhydrous ethanol and added dropwise to the micelle solution. The mixture was then reacted in a constant temperature water bath at 30°C for 8 hours. After centrifugation and washing with deionized water 5 times, the PAA template was completely removed, and the mixture was dried to obtain porous hollow SiO2 particles.

[0031] S3. Synergistic modification treatment: 20 parts of anhydrous ethanol were used to disperse SiO2 particles, which were ultrasonically dispersed for 40 min. 0.5 parts of KH550 were added to prepare solution A. 0.8 parts of PEG-PLA were dissolved in 20 parts of ethanol solution and stirred in a water bath at 50℃ for 60 min to obtain a mixed solution. After mixing, the mixture was stirred at room temperature for 3 h to obtain a modified particle dispersion.

[0032] S4. Preparation of rubber slurry: 50 parts styrene-butadiene rubber, 1.2 parts zinc oxide, 1 part stearic acid, 0.6 parts accelerator CZ, and 1.2 parts sulfur are mixed at 90℃ and 50r / min for 20min to obtain a uniformly mixed rubber slurry.

[0033] S5. Composite modification and molding: 50 parts of modified particle dispersion were added to rubber slurry and mixed at 100℃ and 50r / min for 80min. After the ethanol was fully volatilized, a composite slurry was formed. The mixture was vulcanized at 170℃ and 12MPa for 30min and then cooled and demolded to obtain a high wear-resistant nanofiller modified rubber material.

[0034] Comparative Example 1 Blank group without SiO2 filler, raw material ratio (parts by mass) Styrene-butadiene rubber 50 parts, zinc oxide 1.1 parts, stearic acid 0.8 parts, accelerator CZ 0.5 parts, sulfur 1.0 parts, anhydrous ethanol 45 parts.

[0035] Preparation steps Except for not adding porous hollow SiO2 particles and replacing the modified dispersion with an equal amount of anhydrous ethanol, the other raw material ratios, process steps, and process parameters are completely consistent with those in Example 2. Pure styrene-butadiene rubber material was prepared according to the mixing, internal mixing, and vulcanization conditions of Example 2 and used to compare the performance of the blank substrate.

[0036] Comparative Example 2 For the group with lower ammonia usage, the raw material ratio (parts by mass) is as follows. Except for step S1, where the mass fraction of 25% ammonia water was adjusted to 2 parts (far lower than the 5.5 parts in Example 2), the proportions and amounts of the other raw materials were completely consistent with those in Example 2.

[0037] Preparation steps S1. Preparation of water-soluble micelle template: 0.4 parts of polyacrylic acid were dissolved in 2 parts of 25% ammonia water, stirred and dissolved, and then added dropwise to 110 parts of anhydrous ethanol. The mixture was stirred for 40 min to obtain a micelle solution.

[0038] The remaining preparation steps, process temperature, rotation speed, time, pressure and other parameters of S2-S5 are exactly the same as those in Example 2. Due to the significant reduction in the amount of ammonia water, the hydrolysis rate of TEOS is slow, and SiO2 is deposited uniformly and densely on the micelle surface, making it impossible to form a porous hollow structure. Finally, a dense SiO2 particle modified rubber material is obtained, which is used to compare the performance changes caused by the difference in filler structure.

[0039] Figure 1 (a) and Figure 1 (b) in the figure are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the porous hollow SiO2 particles prepared in Example 1, respectively.

[0040] As can be seen from the figure, the prepared SiO2 particles exhibit a distinct hollow core-shell structure with non-closed pores in the shell. This indicates that under high ammonia catalytic conditions, rapid and uneven deposition of TEOS can effectively form a porous hollow structure.

[0041] Figure 2TEM image of SiO2 particles prepared for Comparative Example 2.

[0042] Because the amount of ammonia water used was significantly reduced, the hydrolysis rate of TEOS was slow and the deposition was dense, resulting in hollow SiO2 particles with a dense shell. This indicates that the amount of ammonia water used is a key factor in regulating the structure of the SiO2 shell.

[0043] Figure 3 This is a diagram of the Tyndall effect in PAA micelle solutions.

[0044] The presence of a distinct optical path when the light beam passes through the micelle system indicates the formation of nanoscale micelle aggregates within the system. This allows tetraethyl orthosilicate (TEA) to hydrolyze and deposit onto the PAA micelles. By controlling the amount of ammonia as a catalyst, the rate of TEA hydrolysis to SiO2 can be adjusted, resulting in a loose, porous structure. Furthermore, after the reaction, the PAA micelles are soluble in deionized water, allowing the micelle template to be removed by washing with water, yielding porous, hollow SiO2 nanoparticles.

[0045] Figure 4 The surface morphology of rubber samples after wear resistance testing in Example 2, Comparative Example 1, and Comparative Example 2 is shown.

[0046] Comparative Example 1 showed severe wear on the surface of pure rubber, with obvious furrows and rough damage; Comparative Example 2 showed reduced wear on the dense SiO2 modified rubber, but still showed obvious wear marks; while Example 2 showed slight wear and shallow scratches on the surface of the porous hollow SiO2 modified rubber.

[0047] Figure 5 The images show the atomic force microscopy (AFM) morphology of the samples from Example 2, Comparative Example 1, and Comparative Example 2 after wear resistance tests. The pure rubber sample from Comparative Example 1 exhibited extremely high surface roughness after wear, with obvious ploughing grooves and severe surface undulations. The dense SiO2 modified rubber from Comparative Example 2 showed a decrease in surface roughness after wear, but still exhibited deep scratches and localized protrusions. In contrast, the porous hollow SiO2 modified rubber from Example 2 had the smoothest wear surface with significantly reduced roughness, indicating its superior wear resistance.

[0048] Figure 6 The stress-strain curves of the samples in Example 2, Comparative Example 1, and Comparative Example 2 are shown.

[0049] The sample in Comparative Example 1 has good toughness but weak strength, while the sample in Comparative Example 2 has significantly increased tensile strength but significantly decreased elongation at break. Compared with Comparative Example 1, the sample in Example 2 does not have a significant decrease in elongation at break but has significantly increased tensile strength, achieving a balance of high strength, high wear resistance and high toughness. This shows that the structural design of the present invention can avoid the problem of rubber toughness loss caused by traditional solid fillers.

Claims

1. A method for preparing a high-wear-resistant nanofiller modified rubber material, characterized in that, By weight, the following steps are included: S1. Dissolve 0.3-0.5 parts of polyacrylic acid in 5-6 parts of 25% ammonia water, and add it dropwise to 100-120 parts of anhydrous ethanol to obtain a water-soluble micelle solution. S2. Dissolve 2-2.4 parts of tetraethyl orthosilicate in 10-12 parts of anhydrous ethanol, and slowly add it dropwise to the above micelle solution to react. Centrifuge and wash with water to remove the polyacrylic acid template to obtain porous hollow SiO2 particles. S3. Prepare solution A by mixing porous hollow SiO2 particles, anhydrous ethanol and silane coupling agent KH550. Dissolve PEG-PLA block copolymer in ethanol solution to prepare mixed solution. Mix and stir to obtain modified porous hollow SiO2 dispersion. S4. Styrene-butadiene rubber, zinc oxide, stearic acid, accelerator CZ, and sulfur are mixed to obtain a rubber slurry; S5. The modified particle dispersion is added to the rubber slurry and mixed to remove the solvent. After vulcanization and cooling, a high wear-resistant nanofiller modified rubber material is obtained. The viscosity-average molecular weight of the polyacrylic acid in step S1 is Mv=3000; In step S3, by mass parts: the amount of silane coupling agent KH550 is 0.3~0.5 parts, and the amount of PEG-PLA block copolymer is 0.6~0.8 parts; In step S4, by weight: 50 parts styrene-butadiene rubber, 1-1.2 parts zinc oxide, 0.5-1 part stearic acid, 0.4-0.6 parts accelerator CZ, and 0.8-1.2 parts sulfur; In step S5, the mass fraction of the modified particle dispersion added is 40-50 parts.

2. The preparation method according to claim 1, characterized in that, In step S2, the reaction temperature is 30°C and the reaction time is 6-8 hours.

3. The preparation method according to claim 1, characterized in that, The mixing time in step S3 is 2-3 hours.

4. The preparation method according to claim 1, characterized in that, In step S4, the mixing temperature is 80~90℃, the rotation speed is 40~50r / min, and the mixing time is 15~20min.

5. The preparation method according to claim 1, characterized in that, In step S5, the mixing temperature is 90~100℃ and the mixing time is 60~80min.

6. The preparation method according to claim 1, characterized in that, In step S5, the vulcanization temperature is 160~170℃, the vulcanization pressure is 10~12MPa, and the vulcanization time is 25~30min.

7. A high-wear-resistant nanofiller modified rubber material, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 6.

Images