Ionized surface treatment aramid pulp enhanced peroxide fluorine rubber compound and preparation method thereof

Abstract

The invention relates to the field of polymer composite materials, and provides an ionized surface treatment aramid pulp enhanced peroxide fluorine rubber compound for improving wear resistance and fatigue resistance through dynamic covalent bonds and gradient interface design. According to the rubber compound, fluoroperoxide rubber is used as a matrix, and aramid pulp treated by ionic liquid containing dynamic disulfide bonds and a novel filler compounded by boron nitride nanosheets and carbon black are added; an aramid surface gradient layer is formed through layer-by-layer impregnation, a reversible covalent bond network is formed during vulcanization, and interface self-repairing is achieved; by combining low-temperature plasma-assisted banburying and segmented vulcanization processes, the wear resistance and fatigue resistance of the material are remarkably improved, and compared with a traditional material, the material is better in performance and has wide application potential.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer composite materials, and in particular to an ionized surface treated aramid pulp reinforced peroxide fluororubber compound with improved wear resistance and fatigue resistance through dynamic covalent bonds and gradient interface design, and a preparation method thereof. Background Art

[0002] In the field of polymer composites, aramid / fluoroperoxide rubber composites are widely used in many key fields such as aerospace, automobile manufacturing, and industrial sealing due to their unique performance advantages, such as high strength, high modulus, and good chemical corrosion resistance. However, existing aramid / fluoroperoxide rubber composites have exposed many problems that need to be solved in practical applications, which seriously restricts their further performance improvement and expansion of their application scope.

[0003] In traditional aramid / peroxide fluororubber composites, interfacial bonding mainly relies on static physical or chemical bonds, such as the common carbon-carbon double bonds treated with ionic liquids. This static interfacial bonding method has obvious defects. When the material is subjected to cyclic stress, the interface lacks dynamic adaptability and cannot effectively buffer and disperse stress, making interfacial failure very likely to occur. Once the interface fails, stress cannot be effectively transmitted, which will lead to stress concentration inside the material, thereby triggering the initiation and expansion of cracks, and ultimately causing a sharp decline in material performance, seriously affecting the reliability and service life of the composite material.

[0004] The uniformity of aramid dispersion within a peroxide fluororubber matrix is ​​a key factor influencing the performance of composite materials. Existing processing methods struggle to achieve uniform aramid dispersion, leading to aramid agglomeration and uneven distribution within the matrix. Aramid agglomeration not only reduces its reinforcing effect on the matrix, preventing the full realization of the composite's mechanical properties, but also leads to material instability, significant performance variations between batches, and increased difficulty in quality control during production.

[0005] Due to these interfacial bonding and aramid dispersion uniformity issues, the wear resistance and fatigue resistance of traditional aramid / peroxide fluororubber composites struggle to meet the increasingly demanding demands of industrial applications. In abrasive environments, the material surface is susceptible to wear and tear, resulting in a high wear rate, significantly shortening the material's service life and increasing equipment maintenance costs and downtime. Furthermore, under cyclic stress, the material is prone to fatigue damage and has a low tear strength retention rate, failing to meet the requirements for long-term stable operation, limiting its application in applications requiring extremely high material performance.

[0006] To address these issues, our company has made some attempts using existing technologies, but the results have been less than ideal. For example, we have tried improving interfacial bonding by changing the type of ionic liquid or adding additives. However, these methods can only improve interfacial performance to a certain extent and cannot fundamentally address the problem of interfacial failure under cyclic stress. Furthermore, existing process optimization methods are limited in improving the uniformity of aramid dispersion, making it difficult to achieve uniform dispersion of aramid in the matrix. Summary of the Invention

[0007] Based on the above-mentioned technical gaps, the present invention is committed to developing a polymer composite material with excellent wear resistance and fatigue resistance. By introducing dynamic covalent bonds and gradient interface design concepts, an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound is innovatively prepared. This material uses peroxide fluororubber raw rubber as a matrix, combined with aramid pulp treated with dynamic disulfide bond ionic liquid and optimized compounded new fillers, to achieve interface self-repair and improved stress transfer efficiency. Through a unique layer-by-layer impregnation process and coordinated low-temperature plasma-assisted mixing, segmented vulcanization and other processes, the present invention significantly improves the comprehensive performance of the compound, providing a new solution for the preparation of high-performance rubber products.

[0008] The technical solution adopted by the present invention to solve the technical problem is: an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound, comprising the following components in parts by weight:

[0009] Peroxide fluororubber matrix: 100 parts of peroxide fluororubber, fluorine content 62-72%, Mooney viscosity ML (1+10min) 121℃ 20-60;

[0010] Modified aramid pulp: chopped aramid with an aspect ratio of 500:1, treated with an ionic liquid containing dynamic disulfide bonds, with an addition amount of 15-30 parts;

[0011] New filler: 8-12 parts of boron nitride nanosheets and 20-40 parts of carbon black N550;

[0012] Dynamic vulcanization system: 2 to 4 parts of disulfide bond-containing peroxide vulcanizer and 1 to 3 parts of accelerator;

[0013] The modified aramid pulp is treated by a layer-by-layer impregnation process to form a gradient layer on the aramid surface with a decreasing ionic liquid concentration from the inside to the outside, with a concentration gradient of 0.5 g / L→0.05 g / L; the peroxide fluororubber compound is prepared by the following method: during the vulcanization process, the ionic liquid containing dynamic disulfide bonds forms a reversible covalent bond network with the peroxide fluororubber matrix.

[0014] A method for preparing an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound comprises the following steps:

[0015] S1. Gradient impregnation: The chopped aramid fibers were sequentially immersed in ethanol solutions of 1-allyl-3-vinylimidazole dithiocarbonate at different concentrations, with the concentrations ranging from 0.5 g / L to 0.05 g / L. After each layer of impregnation, the solution was dried and then stacked to obtain gradient ionic liquid-treated aramid fibers.

[0016] S2. Preparation of aramid pulp masterbatch: 100 parts of peroxide fluororubber raw rubber are rolled on an open mill; 10-20 parts of carbon black N550 and 10-20 parts of aramid pulp treated with gradient ionic liquid are mixed evenly; the above mixture is slowly added to the peroxide fluororubber raw rubber; thinly pass the mixture evenly and produce a sheet with a thickness of 2-4 mm; cut the sheet into small pieces with scissors, add 1.5-3 times the amount of solvent butyl acetate, stir evenly, and stir for 2 hours; finally, dry at 100°C for 12 hours;

[0017] S3. Preparing a peroxide fluororubber mix: weighing 50-70 parts of peroxide fluororubber, 40-60 parts of the aramid pulp masterbatch prepared in step S2, 8-15 parts of boron nitride nanosheets, 25-35 parts of carbon black N550, 2-4 parts of a disulfide bond-containing peroxide vulcanizing agent, and 1-3 parts of an accelerator; and uniformly mixing the above components on an open mill;

[0018] S4, low temperature plasma assisted mixing: plasma treatment is introduced during the mixing stage with a power of 50W to activate the filler surface;

[0019] S5, staged vulcanization: the first stage is pre-vulcanization at 120℃ for 5 minutes to form dynamic bonds; the second stage is secondary vulcanization at 160℃ for 15 minutes.

[0020] The ionic liquid containing dynamic disulfide bonds is 1-allyl-3-vinylimidazole dithiocarbonate.

[0021] The reversible covalent bond network can be broken and reorganized under stress to achieve interface self-repair; the surface ionic liquid concentration gradient of the gradient ionic liquid-treated aramid can effectively optimize the stress transfer efficiency.

[0022] In the step S1, the drying temperature after each layer of dipping is 50-80° C., and the drying time is 1-2 hours.

[0023] In step S3, the roller temperature of the mixing mill is controlled at 50-60°C.

[0024] In step S4, the plasma treatment time is 5-10 minutes.

[0025] The wear resistance of the peroxide fluorine rubber compound is improved compared with traditional materials, and the Akron wear volume is reduced by more than 40%.

[0026] The peroxide fluorine rubber compound has excellent fatigue resistance, and the tear strength retention rate after the cyclic compression test (100,000 times) is greater than 90%.

[0027] The invention relates to the application of the ionized surface treated aramid pulp reinforced peroxide fluororubber compound in the preparation of high performance rubber products.

[0028] The beneficial effects of the present invention are as follows: the ionized surface-treated aramid pulp reinforced perfluororubber compound and the preparation method thereof of the present invention effectively solve the above-mentioned problems through a unique innovative design. More specifically, an ionic liquid containing a dynamic disulfide bond (such as 1-allyl-3-vinylimidazole dithiocarbonate) is used to treat the aramid, and a reversible covalent bond network is formed with the perfluororubber matrix during the vulcanization process. The bond can be broken and reorganized under stress to achieve interface self-repair, thereby solving the problem that traditional static interface bonding is prone to failure under cyclic stress; a gradient layer with decreasing ionic liquid concentration from the inside to the outside is formed on the surface of the aramid through a layer-by-layer impregnation process, thereby optimizing the stress transfer efficiency and improving the dispersion uniformity of the aramid; at the same time, the compounding of the new filler boron nitride nanosheets and carbon black N550, as well as processes such as low-temperature plasma-assisted internal mixing and segmented vulcanization, synergistically improve the wear resistance and fatigue resistance of the material, so that the perfluororubber compound of the present invention has significantly improved performance compared with traditional materials and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the preparation process of the present invention;

[0030] Figure 2 It is a schematic diagram of the preparation process of aramid pulp masterbatch in the present invention. DETAILED DESCRIPTION

[0031] The following is in conjunction with the instructions Figure 1-2 , the specific implementation manner of the present invention is described in detail through specific examples:

[0032] Example 1: Preparation of high-performance wear-resistant and fatigue-resistant ionized surface-treated aramid pulp reinforced peroxide fluororubber compound

[0033] 1. Raw material preparation

[0034] Peroxide fluororubber matrix: 100 parts of peroxide fluororubber, fluorine content 62-72%, Mooney viscosity ML (1+10min) 121℃ 20-60.

[0035] Modified aramid pulp: Chopped aramid with an aspect ratio of 500:1 is processed through a layer-by-layer impregnation process. The specific steps are as follows:

[0036] The aramid was sequentially immersed in 1-allyl-3-vinylimidazole dithiocarbonate ethanol solutions with concentrations of 0.5 g / L, 0.25 g / L, and 0.05 g / L, respectively. After each layer of immersion, it was dried at 60°C for 1.5 hours, and then the next layer of immersion was stacked until the gradient ionic liquid-treated aramid was formed.

[0037] New filler: Weigh 8 parts of boron nitride nanosheets and 20 parts of carbon black N550 and mix them evenly.

[0038] Dynamic vulcanization system: weigh 2 parts of disulfide bond-containing peroxide vulcanizer and 1 part of accelerator.

[0039] 2. Preparation of aramid pulp masterbatch

[0040] Step 1: Prepare the open mill: Place the peroxide fluororubber raw rubber on the open mill and start the open mill to perform the roll wrapping operation; adjust the roll temperature of the open mill to 55°C to ensure that the rubber raw rubber is softened at an appropriate temperature to facilitate subsequent mixing operations.

[0041] Step 2: Mixing carbon black and gradient aramid pulp: Pre-mix carbon black N550 and aramid pulp treated with gradient ionic liquid in a mixing container to ensure full contact between the two.

[0042] Step 3: Add the mixture to the raw rubber: Slowly add the carbon black and aramid pulp mixture mixed in Step 2 to the peroxide fluororubber raw rubber on the roll mill. Maintain a uniform speed during the addition process to avoid adding too much at once, which may cause uneven mixing.

[0043] Step 4: Thinning: The rubber mixture is thinned on an open mill, with repeated rolling and folding to disperse and evenly mix the components. Once uniformly thinned, the rubber is sheeted to a thickness of 3mm for easy handling.

[0044] Step 5: Solvent treatment: Use scissors to cut the film obtained in step 4 into small pieces to facilitate sufficient penetration and mixing of the solvent; add 2 times the solvent butyl acetate to the cut film; stir the film with added solvent evenly in a stirring device for 2 hours to ensure that the solvent fully dissolves the soluble components in the rubber and promotes further dispersion of each component.

[0045] Step 6: Drying: Place the mixture stirred in step 5 in a drying device and dry it at 100°C; the drying time lasts for 12 hours to ensure that the solvent is completely volatilized to obtain a dry aramid pulp masterbatch.

[0046] Through the above steps, aramid pulp masterbatch was successfully prepared, laying the foundation for the subsequent preparation of high-performance ionized surface-treated aramid pulp reinforced peroxide fluororubber compound.

[0047] 3. Preparation of peroxide fluorine rubber compound

[0048] Weigh 50 parts by weight of peroxide fluororubber, 40 parts of aramid pulp masterbatch, 8 parts of boron nitride nanosheets, 25 parts of carbon black N550, 2 parts of disulfide bond-containing peroxide vulcanizing agent, and 1 part of accelerator. Mix the above ingredients evenly on an open mill with the roller temperature controlled at 55°C.

[0049] 4. Low temperature plasma assisted mixing

[0050] The uniformly mixed rubber material was put into an internal mixer, and plasma treatment was introduced during the internal mixing stage with a power of 50W to activate the filler surface. The treatment time was 7 minutes.

[0051] 5. Segmented vulcanization

[0052] The first stage is pre-curing at 120℃ for 5 minutes to form dynamic bonds.

[0053] In the second stage, final vulcanization is performed at 160°C for 15 minutes to obtain a high-performance wear-resistant and fatigue-resistant ionized surface-treated aramid pulp reinforced peroxide fluororubber compound.

[0054] The experimental process and results of this embodiment in practice are as follows:

[0055] Akron abrasion test: Using an MR-H3B high-speed ring-block wear tester, the test was conducted for 90 minutes at a pressure of 20N, a rotation speed of 300rpm, and room temperature. The results showed that the rubber compound of Example 1 of the present invention achieved significant improvement in wear resistance. Specifically, the wear volume of the conventional aramid / peroxide fluororubber composite rubber compound is generally 0.15 to 0.20 cm 3 / 1.61km, while Example 1 of the present invention significantly reduces the wear volume of the rubber mix to no more than 0.12KM / cm by using an ionic liquid containing dynamic disulfide bonds to treat aramid, implementing a gradient ionic liquid treatment process, and combining innovative technologies such as new fillers and low-temperature plasma-assisted mixing. 3 , which is more than 20% lower than that of traditional materials. This significant difference in data fully demonstrates the excellent effect of the present invention in improving the wear resistance of rubber compounds, showing that it has better durability and stability in practical applications.

[0056] Fatigue resistance: After a cyclic compression test (100,000 times), the tear strength retention rate was 95%, which is much higher than the 80% of the aramid / fluoroperoxide rubber composite material treated with static ionic liquid in the prior art.

[0057] Tear resistance: The test result is 55N / mm, which is significantly better than the 45N / mm of traditional materials.

[0058] This embodiment significantly improves the wear resistance and fatigue resistance of peroxide fluororubber rubber mixes by treating aramid pulp with a gradient ionic liquid, combined with innovative processes such as low-temperature plasma-assisted mixing and segmented vulcanization. The examples show that the wear rate of the mix is ​​significantly reduced, the tear strength is significantly improved, and after multiple bending fatigue tests, the tear strength retention rate exceeds 90%. This technical solution effectively solves the problems of weak interface bonding and uneven aramid dispersion in traditional aramid / peroxide fluororubber composites. The resulting mix has a longer service life and better overall performance, making it suitable for the preparation of high-performance rubber products.

[0059] Example 2: Preparation of high-strength, high-toughness, wear-resistant, and fatigue-resistant ionized surface-treated aramid pulp reinforced peroxide fluororubber compound

[0060] 1. Raw material preparation

[0061] Fluororubber peroxide matrix: same as in Example 1.

[0062] Modified aramid pulp: same as in Example 1.

[0063] New filler: Weigh 9 parts of boron nitride nanosheets and 31 parts of carbon black N550 and mix them evenly.

[0064] Dynamic vulcanization system: weigh 3 parts of disulfide bond-containing peroxide vulcanizer and 2 parts of accelerator.

[0065] 2. Preparation of aramid pulp masterbatch: same as in Example 1.

[0066] 3. Preparation of peroxide fluorine rubber compound

[0067] Weigh 59 parts peroxide fluororubber, 49 parts aramid pulp masterbatch, 13 parts boron nitride nanosheets, 31 parts carbon black N550, 3 parts disulfide bond-containing peroxide vulcanizing agent, and 2 parts accelerator by weight and mix the above ingredients evenly on an open mill with the roller temperature controlled at 55°C.

[0068] 4. Low temperature plasma assisted internal mixing: same as in Example 1.

[0069] 5. Segmented vulcanization: same as in Example 1.

[0070] The experimental process and results of this embodiment in practice are as follows:

[0071] Akron abrasion test: the test conditions are the same as those in Example 1. The results show that the wear resistance of the rubber compound in Example 2 of the present invention is reduced by 52% compared with that in Example 1, and the wear resistance reaches the best.

[0072] Fatigue resistance: After cyclic compression testing (100,000 times), the tear strength retention rate is 97%, showing extremely high fatigue resistance.

[0073] Tear resistance: The test result is 59 N / mm, which is significantly improved compared with Example 1 and the traditional material, indicating that the material performs well in terms of high strength and high toughness.

[0074] Example 3: Preparation of high-intensity ionized surface-treated aramid pulp reinforced peroxide fluororubber compound

[0075] 1. Raw material preparation

[0076] Fluororubber peroxide matrix: same as in Example 1.

[0077] Modified aramid pulp: Gradient ionic liquid-treated aramid was prepared using the same process, but the ionic liquid concentration was adjusted to 0.4 g / L, 0.2 g / L, and 0.04 g / L to meet different performance requirements.

[0078] New filler: Weigh 11 parts of boron nitride nanosheets and 32 parts of carbon black N550 and mix them evenly to further optimize the material properties.

[0079] Dynamic vulcanization system: same as in Example 1.

[0080] 2. Preparation of aramid pulp masterbatch

[0081] The steps are the same as those in Example 1, but the thickness of the sheets is adjusted to 2.5 mm to meet the requirements of different formulations.

[0082] 3. Preparation of peroxide fluorine rubber compound

[0083] Weigh each component by weight, including 51 parts of aramid pulp masterbatch to fine-tune the mechanical properties of the material. Mix evenly on an open mill with the roll temperature controlled at 58°C.

[0084] 4. Low temperature plasma assisted mixing

[0085] The same as Example 1, but the plasma treatment time is adjusted to 8 minutes to enhance the interface bonding strength between the filler and the matrix.

[0086] 5. Segmented vulcanization

[0087] Same as Example 1, but the final vulcanization temperature was adjusted to 165° C. to further optimize the vulcanization effect.

[0088] Experimental process and results

[0089] Wear resistance test: The test conditions were the same as those in Example 1. The results showed that the wear rate was reduced by 32% compared with Example 1, and the wear resistance was further improved.

[0090] Fatigue resistance: After cyclic compression testing (100,000 times), the tear strength retention rate is 96%, showing extremely high fatigue resistance.

[0091] Tear resistance: The test result is 58 N / mm, which is significantly improved compared with Example 1 and the traditional material, indicating that the material performs well in terms of high strength and high toughness.

[0092] Example 4: Preparation of high-toughness ionized surface-treated aramid pulp reinforced peroxide fluororubber compound

[0093] 1. Raw material preparation

[0094] Fluororubber peroxide matrix: same as in Example 1.

[0095] Modified aramid pulp: Gradient ionic liquid-treated aramid was prepared using the same process, but the ionic liquid concentration was adjusted to 0.4 g / L, 0.2 g / L, and 0.04 g / L to meet different performance requirements.

[0096] New filler: Weigh 12 parts of boron nitride nanosheets and 40 parts of carbon black N550 and mix them evenly to further optimize the material properties.

[0097] Dynamic vulcanization system: same as in Example 1.

[0098] 2. Preparation of aramid pulp masterbatch

[0099] The steps are the same as those in Example 1, but the thickness of the sheets is adjusted to 2.5 mm to meet the requirements of different formulations.

[0100] 3. Preparation of peroxide fluorine rubber compound

[0101] Weigh each component by weight, wherein the amount of aramid pulp masterbatch added is 60 parts, and mix them evenly on an open mill with the roller temperature controlled at 58°C.

[0102] 4. Low temperature plasma assisted mixing

[0103] The same as Example 1, but the plasma treatment time is adjusted to 8 minutes to enhance the interface bonding strength between the filler and the matrix.

[0104] 5. Segmented vulcanization

[0105] Same as Example 1, but the second-stage vulcanization temperature was adjusted to 165° C. to further optimize the vulcanization effect.

[0106] Experimental process and results

[0107] Wear resistance test: The test conditions were the same as those in Example 1. The results showed that the wear rate was reduced by 41% compared with Example 1, and the wear resistance was further improved.

[0108] Fatigue resistance: After cyclic compression testing (100,000 times), the tear strength retention rate is 94%, showing high fatigue resistance.

[0109] Tear resistance: The test result is 60N / mm, which is significantly improved compared with Example 1 and the traditional material, indicating that the material performs extremely well in terms of high toughness.

[0110] Through the preparation and testing of the above four embodiments, it can be clearly seen that the ionized surface-treated aramid pulp reinforced peroxide fluororubber compound provided by the present invention is superior to the existing technology in terms of wear resistance, fatigue resistance and tear resistance, and effectively solves the interface bonding and aramid dispersion uniformity problems existing in traditional aramid / peroxide fluororubber composite materials, and has broad application prospects.

[0111] Comparative analysis:

[0112] The technical solution of the present application is compared with the prior art of Patent No. 2022101833801, which is a high-wear-resistant rubber-based composite material and its preparation method. The present technical solution provides an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound, which mainly includes the following components in parts by weight:

[0113] Peroxide fluororubber matrix: 100 parts of peroxide fluororubber, fluorine content 62-72%, Mooney viscosity ML (1+10min) 121℃ 20-60;

[0114] Modified aramid pulp: chopped aramid with an aspect ratio of 500:1, treated with an ionic liquid containing dynamic disulfide bonds, with an addition amount of 15-30 parts;

[0115] New filler: 8-12 parts of boron nitride nanosheets and 20-40 parts of carbon black N550;

[0116] Dynamic vulcanization system: 2 to 4 parts of disulfide bond-containing peroxide vulcanizer and 1 to 3 parts of accelerator;

[0117] The modified aramid pulp is treated by a layer-by-layer impregnation process to form a gradient layer on the aramid surface with a decreasing ionic liquid concentration from the inside to the outside, with a concentration gradient of 0.5 g / L→0.05 g / L; the peroxide fluororubber compound is prepared by the following method: during the vulcanization process, the ionic liquid containing dynamic disulfide bonds forms a reversible covalent bond network with the peroxide fluororubber matrix.

[0118] The comparative example provides a highly wear-resistant rubber-based composite material and a preparation method thereof, comprising the following raw materials in parts by weight:

[0119] 100 parts of rubber, 2-12 parts of active agent, 0.5-2 parts of antioxidant, 20-70 parts of carbon black, 1-20 parts of plasticizer, 0.5-2 parts of vulcanizing agent, 0.5-2 parts of accelerator, and 1-50 parts of aramid treated with ionic liquid ethanol solution.

[0120] The technical solution of this application treats aramid with an ionic liquid containing dynamic disulfide bonds (such as 1-allyl-3-vinyl imidazole dithiocarbonate), forming a reversible covalent bond network with the peroxide fluororubber matrix during the vulcanization process. The bond can break and reorganize under stress, achieving interface self-repair, thereby solving the problem that traditional static interface bonding is prone to failure under cyclic stress. The comparative example treats aramid with an ionic liquid containing double bonds on the side chain of the cationic structure, thereby improving the compatibility of aramid with the rubber matrix and the chemical bonding ability with the rubber, and improving the mechanical properties and wear resistance of the rubber-based composite material. However, there may be deficiencies in dynamic adaptability, and the two differ in their implementation methods.

[0121] The present invention provides a method for preparing an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound, comprising the following steps:

[0122] S1. Gradient impregnation: The chopped aramid fibers were sequentially immersed in ethanol solutions of 1-allyl-3-vinylimidazole dithiocarbonate at different concentrations, with the concentrations ranging from 0.5 g / L to 0.05 g / L. After each layer of impregnation, the solution was dried and then stacked to obtain gradient ionic liquid-treated aramid fibers.

[0123] S2. Preparation of aramid pulp masterbatch: Rolling peroxide fluororubber raw rubber on an open mill; Evenly mixing carbon black N550 and gradient ionic liquid treated aramid pulp; Slowly adding the mixture to the peroxide fluororubber raw rubber; Thinly passing the mixture evenly and producing a sheet with a thickness of 2-4 mm; Cutting the sheet into small pieces with scissors, adding 1.5-3 times the amount of solvent butyl acetate, stirring evenly for 2 hours; Drying at 100°C for 12 hours;

[0124] S3. Preparing a peroxide fluororubber compound: weighing 50-70 parts of peroxide fluororubber, 40-60 parts of the aramid pulp masterbatch prepared in step S2, 8-15 parts of boron nitride nanosheets, 25-35 parts of carbon black N550, 2-4 parts of a disulfide bond-containing peroxide vulcanizing agent, and 1-3 parts of an accelerator; and uniformly mixing the above components on an open mill;

[0125] S4, low temperature plasma assisted mixing: plasma treatment is introduced during the mixing stage with a power of 50W to activate the filler surface;

[0126] S5. Staged vulcanization: The first stage is pre-vulcanization at 120°C for 5 minutes to form dynamic bonds; the second stage is final vulcanization at 160°C for 15 minutes.

[0127] The method for treating aramid with ionic liquid in the comparative example includes the following steps:

[0128] (1) adding the ionic liquid to ethanol and fully dissolving it to obtain an ionic liquid ethanol solution;

[0129] (2) immersing the aramid fiber in the ionic liquid ethanol solution;

[0130] (3) Drying the soaked aramid.

[0131] This technical solution innovatively prepares an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound by introducing the concept of dynamic covalent bonds and gradient interface design. The material uses hydrogenated nitrile rubber and polyurethane elastomer as the matrix, combined with aramid pulp treated with dynamic disulfide bond ionic liquid and optimized compounded new fillers, to achieve interface self-repair and improved stress transfer efficiency. Through a unique layer-by-layer impregnation process and coordinated low-temperature plasma-assisted mixing, segmented vulcanization and other processes, the present invention significantly improves the comprehensive performance of the compound rubber and provides a new solution for the preparation of high-performance rubber products. Although the comparative example also provides a new method to improve the mechanical properties and wear resistance of composite materials, it does not introduce the concept of dynamic covalent bonds and gradient interface design, nor does it mention the realization of effects such as interface self-repair and improved stress transfer efficiency.

Claims

1. An ionized surface treated aramid pulp reinforced peroxide fluororubber compound, characterized by: The composition comprises the following components in parts by weight: Peroxide fluororubber matrix: 100 parts of peroxide fluororubber, fluorine content 62-72%, Mooney viscosity ML (1+10min) 121℃ 20-60; Modified aramid pulp: chopped aramid with an aspect ratio of 500:1, treated with an ionic liquid containing dynamic disulfide bonds, with an addition amount of 15-30 parts; New filler: 8-12 parts of boron nitride nanosheets and 20-40 parts of carbon black N550; Dynamic vulcanization system: 2 to 4 parts of disulfide bond-containing peroxide vulcanizer and 1 to 3 parts of accelerator; The modified aramid pulp is treated by a layer-by-layer impregnation process to form a gradient layer on the aramid surface with a decreasing ionic liquid concentration from the inside to the outside, with a concentration gradient of 0.5 g / L→0.05 g / L; the peroxide fluororubber compound is prepared by the following method: during the vulcanization process, the ionic liquid containing dynamic disulfide bonds forms a reversible covalent bond network with the peroxide fluororubber matrix.

2. A method for preparing an ionized surface-treated aramid pulp reinforced peroxide fluororubber compound, characterized by: The following steps are involved: S1. Gradient impregnation: The chopped aramid fibers were sequentially immersed in ethanol solutions of 1-allyl-3-vinylimidazole dithiocarbonate at different concentrations, with the concentrations ranging from 0.5 g / L to 0.05 g / L. After each layer of impregnation, the solution was dried and then stacked to obtain gradient ionic liquid-treated aramid fibers. S2. Preparation of aramid pulp masterbatch: 100 parts of peroxide fluororubber raw rubber are rolled on an open mill; 10-20 parts of carbon black N550 and 10-20 parts of aramid pulp treated with gradient ionic liquid are mixed evenly; the above mixture is slowly added to the peroxide fluororubber raw rubber; thinly pass the mixture evenly and produce a sheet with a thickness of 2-4 mm; cut the sheet into small pieces with scissors, add 1.5-3 times the amount of solvent butyl acetate, stir evenly, and stir for 2 hours; finally, dry at 100°C for 12 hours; S3. Prepare a peroxide fluororubber mix: weigh 50-70 parts of peroxide fluororubber, 40-60 parts of the aramid pulp masterbatch prepared in step S2, 8-15 parts of boron nitride nanosheets, 25-35 parts of carbon black N550, 2-4 parts of a disulfide bond-containing peroxide vulcanizing agent, and 1-3 parts of an accelerator; and mix the above components evenly on an open mill; S4, low temperature plasma assisted mixing: plasma treatment is introduced during the mixing stage with a power of 50W to activate the filler surface; S5, staged vulcanization: the first stage is pre-vulcanization at 120℃ for 5 minutes to form dynamic bonds; the second stage is secondary vulcanization at 160℃ for 15 minutes.

3. The ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 1, characterized in that: The ionic liquid containing dynamic disulfide bonds is 1-allyl-3-vinylimidazole dithiocarbonate.

4. The ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 1, characterized in that: The reversible covalent bond network can be broken and reorganized under stress to achieve interface self-repair; the surface ionic liquid concentration gradient of the gradient ionic liquid-treated aramid can effectively optimize the stress transfer efficiency.

5. The method for preparing the ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 2, characterized in that: In the step S1, the drying temperature after each layer of dipping is 50-80° C., and the drying time is 1-2 hours.

6. The method for preparing the ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 2, characterized in that: In step S3, the roller temperature of the mixing mill is controlled at 50-60°C.

7. The method for preparing the ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 2, characterized in that: In step S4, the plasma treatment time is 5-10 minutes.

8. The ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 1, characterized in that: The wear resistance of the peroxide fluorine rubber compound is improved compared with traditional materials, and the wear rate is reduced by more than 40%.

9. The ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to claim 1, characterized in that: The peroxide fluorine rubber compound has excellent fatigue resistance, and the tear strength retention rate after the cyclic compression test is greater than 90%.

10. The ionized surface treated aramid pulp reinforced peroxide fluororubber compound according to any one of claims 1 to 9 is suitable for use in the preparation of high-performance rubber products.

Images