Nanoparticle modified nitrile rubber composite material and preparation method thereof

Abstract

The invention relates to the technical field of rubber composite materials, and discloses a nanoparticle modified nitrile rubber composite material and a preparation method thereof. The nanoparticle modified nitrile rubber composite material is prepared from the following components in parts by mass: 100 parts of nitrile rubber, 10-20 parts of modified nitrile rubber, 5-9 parts of a modified fiber additive, 2-4 parts of stearic acid, 3-6 parts of an activating agent, 0.5-1 part of an anti-aging agent, 0.3-0.6 part of an accelerant and 1.5-2.5 parts of a vulcanizing aid, the modified fiber additive is obtained by modifying aramid fibers through multi-walled carbon nanotubes, the raw materials in the composite material are good in dispersity and excellent in compatibility and can be uniformly distributed in a rubber matrix, and through the synergistic effect of the raw materials, the prepared nanoparticle modified nitrile rubber composite material has excellent mechanical strength and aging resistance and can be applied to the field of rubber materials. The comprehensive performance is excellent.

Description

Technical Field

[0001] This invention relates to the field of rubber composite materials technology, specifically to a nanoparticle-modified nitrile butadiene rubber composite material and its preparation method. Background Technology

[0002] Nitrile butadiene rubber (NBR) is a block copolymer prepared by emulsion polymerization of acrylonitrile and 1,3-butadiene. Due to the presence of polar cyano groups in its molecular chain, it exhibits excellent oil resistance and chemical stability, as well as superior processing properties, leading to its wide application in sealing products, industrial rollers, hoses and belts, automobiles, and petrochemicals. However, traditional NBR suffers from insufficient mechanical properties, moderate abrasion resistance, and poor aging resistance, limiting its further applications. Therefore, modification of NBR can effectively improve these shortcomings.

[0003] Nanoparticle modification of nitrile butadiene rubber (NBR) is an effective way to improve its overall performance. Chinese patent application CN101891909A discloses a multifunctional nano-CaCO3-reinforced NBR. The raw materials used in this rubber are as follows: NBR, sulfur, active zinc oxide, modified nano-CaCO3, antioxidant D, dioctyl phthalate, stearic acid, accelerator DM, and accelerator CZ. It is prepared by plasticizing, mixing, and vulcanizing. This rubber exhibits good thermal stability, improved strength and plasticity, and a wider range of applications. However, the high content of nano-CaCO3 filler and the poor reinforcing effect of CaCO3 alone result in generally poor overall performance of the modified rubber. Chinese patent application CN112480500A discloses a modified nitrile rubber composite material, comprising a mixture, chemical agents, and fillers. The mixture includes nitrile rubber, silicone rubber, cis-butadiene rubber, fiber composite material, and nanocomposite material. The chemical agents include hexadecyltrimethylammonium bromide, silane coupling agent, softener, curing agent, vulcanization accelerator, mildew inhibitor, aging inhibitor, and crack inhibitor. The fillers include graphene, precipitated silica, glass fiber, chlorinated paraffin, and sulfur. This modified nitrile rubber composite material effectively improves the mechanical strength, wear resistance, elasticity, and aging resistance of nitrile rubber by adding a multi-component reinforcing phase. However, the overall composition of this nitrile rubber composite material is too complex and difficult to control during processing. The introduced nanoparticles have poor dispersion, and the multi-component synergistic effect is insufficient, affecting the overall performance.

[0004] Therefore, it is of great significance to provide a nanoparticle-modified nitrile rubber composite material with excellent comprehensive performance. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the aforementioned technical problems, this invention provides a nanoparticle-modified nitrile rubber composite material and its preparation method, which solves the problems of nitrile rubber having general mechanical strength and poor aging resistance.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this invention discloses a nanoparticle-modified nitrile rubber composite material, which is made from the following components in parts by weight:

[0009] 100 parts of nitrile rubber, 10-20 parts of modified nitrile rubber, 5-9 parts of modified fiber additives, 2-4 parts of stearic acid, 3-6 parts of activator, 0.5-1 part of antioxidant, 0.3-0.6 parts of accelerator, and 1.5-2.5 parts of vulcanizing aid;

[0010] The modified nitrile rubber is obtained by reacting carboxylated nitrile rubber with epoxidized titanium dioxide;

[0011] The modified fiber additive is obtained by modifying aramid fibers with multi-walled carbon nanotubes;

[0012] The activator is composed of zinc oxide and magnesium oxide in a mass ratio of 2:1;

[0013] The antioxidant is 4,4'-bis(phenylisopropyl)diphenylamine;

[0014] The accelerator is composed of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a mass ratio of 1:1;

[0015] The vulcanization aid is sulfur.

[0016] As a further aspect of the present invention, the preparation method of the modified nitrile rubber includes the following steps:

[0017] S1. Add nano-titanium dioxide and anhydrous ethanol to reaction vessel A, disperse evenly, add γ-glycidyl etheroxypropyltrimethoxysilane, heat up, mix, and keep the temperature at 60-70℃ for 12-15 hours under a nitrogen atmosphere. After the reaction is completed, filter, wash with deionized water and anhydrous ethanol, and dry to obtain epoxidized titanium dioxide.

[0018] S2. Add tetrahydrofuran, carboxylated nitrile rubber, and epoxidized titanium dioxide to reactor B, disperse evenly, and maintain the temperature at 10-35℃ for 8-10 hours under a nitrogen atmosphere. After the reaction is completed, filter, wash with ethyl acetate, and dry to obtain modified nitrile rubber.

[0019] As a further aspect of the present invention: the addition ratio of nano-titanium dioxide, anhydrous ethanol, and γ-glycidyl etheroxypropyltrimethoxysilane in S1 is 10g:(150-180)mL:(1.2-1.6)g.

[0020] As a further aspect of the present invention: the addition ratio of tetrahydrofuran, carboxylated nitrile rubber, and epoxidized titanium dioxide in S2 is (100-120) mL: 10 g: (1-2.5) g.

[0021] As a further aspect of the present invention, the preparation method of the modified fiber additive includes the following steps:

[0022] Step (1): Place the aramid fiber in ethyl acetate, heat it, control the temperature at 80-85℃, keep it warm for 1 hour, cool it, add 1,8-diisocyanate, mix it, control the temperature at 10-35℃, keep it warm for 24-30 hours, after the reaction is complete, filter it, wash it with saturated sodium carbonate solution, dry it, and obtain isocyanate-treated aramid fiber.

[0023] Step (2): Mix acyl chloride multi-walled carbon nanotubes and triethylenetetramine, heat, and keep warm at 115-125℃ for 42-48h in a nitrogen atmosphere. After the reaction is completed, distill under reduced pressure, wash with methanol, and dry to obtain aminated multi-walled carbon nanotubes.

[0024] Step (3): Mix N,N-dimethylformamide, isocyanate-modified aramid fiber, and aminated multi-walled carbon nanotubes evenly, heat, control the temperature at 80-90℃, keep warm for 3-4 hours, after the reaction is completed, distill under reduced pressure, wash with anhydrous ethanol, and dry to obtain modified fiber additive.

[0025] As a further aspect of the present invention: in step (1), the addition ratio of aramid fiber, ethyl acetate and 1,8-diisocyanate is (80-105) mL: 10 g: (0.5-1) g.

[0026] As a further embodiment of the present invention: the preparation method of acyl chloride multi-walled carbon nanotubes in step (2) is as follows: carboxylated multi-walled carbon nanotubes, thionyl chloride, and N,N-dimethylformamide are mixed evenly in a mass ratio of 1:200:80, heated in a nitrogen atmosphere, controlled at 75°C, and kept at the temperature for 24 hours. After the reaction is completed, the mixture is distilled under reduced pressure, washed with tetrahydrofuran, and dried to obtain acyl chloride multi-walled carbon nanotubes.

[0027] As a further aspect of the present invention: in step (2), the addition ratio of acyl chloride multi-walled carbon nanotubes and triethylenetetramine is 1g:(180-210)mL.

[0028] As a further aspect of the present invention: in step (3), the addition ratio of N,N-dimethylformamide, isocyanate-modified aramid fiber, and aminated multi-walled carbon nanotubes is (300-350) mL: 10 g: (5-8) g.

[0029] A method for preparing the nanoparticle-modified nitrile rubber composite material includes the following steps:

[0030] Nitrile rubber was placed in a two-roll mill and the temperature was controlled at 45-55℃ for 4-6 minutes. Stearic acid, modified nitrile rubber, modified fiber additives, activators, accelerators, vulcanizing agents, and antioxidants were added in sequence and mixed evenly. After mixing evenly, the mixture was cooled and left to stand for 24 hours. Then, it was vulcanized in a flat vulcanizing mill and discharged to obtain nanoparticle modified nitrile rubber composite material.

[0031] As a further aspect of the present invention: the mixing temperature is 55-65℃, the rotation speed is 35-45r / min, and the mixing time is 30-40min.

[0032] As a further aspect of the present invention: during the vulcanization process, the vulcanization pressure is 10-15 MPa and the vulcanization temperature is 165-175℃.

[0033] (III) Beneficial Technical Effects

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) The nano-titanium dioxide in this invention possesses excellent mechanical properties, antibacterial properties, and aging resistance, and provides a reinforcing mechanism for nitrile rubber. Modification of nano-titanium dioxide yields epoxidized titanium dioxide. The epoxy groups on the epoxidized titanium dioxide react with the carboxyl groups on the carboxylated nitrile rubber, resulting in modified nitrile rubber. The nano-titanium dioxide is uniformly dispersed within the carboxylated nitrile rubber, effectively preventing agglomeration. Simultaneously, hydroxyl groups are introduced, enabling hydrogen bonding with the cyano groups of the nitrile rubber, enhancing interfacial bonding, restricting chain segment movement of the rubber molecules, and improving modulus and strength. When the modified nitrile rubber is blended with the nitrile rubber matrix, this reinforcing network effectively restricts the relative sliding of the rubber molecular chains, improving the tensile strength and tear strength of the composite material. Furthermore, due to the similar structure between the modified nitrile rubber and the nitrile rubber matrix, it exhibits good compatibility and can be uniformly distributed within the matrix, further enhancing the overall mechanical properties of the material.

[0036] (2) In this invention, aramid fibers possess high strength and high modulus, while multi-walled carbon nanotubes exhibit excellent mechanical strength, strong wear resistance, and good heat resistance. Aramid fibers are modified by introducing isocyanate and alkyl long chains onto them to obtain isocyanate-modified aramid fibers. Triethylenetetramine is used to modify acyl chloride multi-walled carbon nanotubes, introducing amino groups onto the carbon nanotubes, which react with the isocyanate on the isocyanate-modified aramid fibers to obtain modified fiber additives. Aramid fibers and multi-walled carbon nanotubes are connected by chemical bonds, constructing a synergistic reinforcing network that enhances the mechanical properties of nitrile rubber. Under external force, aramid fibers bear the main load, inhibiting crack propagation, while multi-walled carbon nanotubes uniformly transfer stress to the nitrile rubber matrix, avoiding stress concentration and significantly improving the mechanical properties of the composite material. Furthermore, the modified fiber additives are well dispersed in the rubber matrix and exhibit strong interfacial interactions with the rubber molecular chains, further enhancing the mechanical properties of the composite material.

[0037] (3) In this invention, nano-titanium dioxide is filled into the matrix as rigid particles, and multi-walled carbon nanotubes and aramid fibers serve as the skeleton structure to bear the principal stress, forming a mechanical network structure that can effectively improve the tensile strength and elongation at break of the matrix. Nano-titanium dioxide has excellent ultraviolet shielding and absorption properties, effectively absorbing and scattering ultraviolet rays, converting ultraviolet energy into harmless heat energy, and preventing ultraviolet rays from damaging the molecular chains of nitrile rubber. Moreover, epoxidized titanium dioxide has high chemical stability, which can continuously provide protection for the rubber matrix, inhibit the oxidative degradation reaction of the rubber molecular chains, delay the aging process of the material, and improve the weather resistance of the composite material. Multi-walled carbon nanotubes have excellent heat dissipation function and excellent thermal stability. The heat-conducting network formed can accelerate the heat dissipation rate of the rubber matrix, reduce the local overheating phenomenon during the vulcanization process, and inhibit the performance degradation caused by thermo-oxidative aging during long-term use. The two work synergistically to provide double protection to delay the aging of the rubber matrix, have a good reinforcing effect, and the nanoparticles have excellent compatibility with the matrix.

[0038] (4) This invention uses a compound accelerator and an activator. The compound activator can accelerate vulcanization cracking, and the compound accelerator can be effective in both low and high temperature environments, extending the vulcanization plateau period. The added additives can effectively prevent scorching, shorten the vulcanization time, and improve production efficiency. The resulting nanoparticle-modified nitrile rubber composite material has excellent mechanical strength and aging resistance, and excellent overall performance. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] A method for preparing modified nitrile butadiene rubber includes the following steps:

[0042] S1. Add 10g of nano titanium dioxide and 150mL of anhydrous ethanol to reaction vessel A. After dispersing evenly, add 1.2g of γ-glycidyl etheroxypropyltrimethoxysilane, heat up, mix, and keep the temperature at 60℃ for 15h under a nitrogen atmosphere. After the reaction is completed, filter, wash with deionized water and anhydrous ethanol, and dry to obtain epoxidized titanium dioxide.

[0043] S2. Add 100 mL of tetrahydrofuran, 10 g of carboxylated nitrile rubber, and 1 g of epoxidized titanium dioxide to reactor B, disperse evenly, and maintain the temperature at 10 °C for 10 h under a nitrogen atmosphere. After the reaction is completed, filter, wash with ethyl acetate, and dry to obtain modified nitrile rubber.

[0044] Example 2

[0045] A method for preparing modified nitrile butadiene rubber includes the following steps:

[0046] S1. Add 10g of nano titanium dioxide and 160mL of anhydrous ethanol to reaction vessel A. After dispersing evenly, add 1.4g of γ-glycidyl etheroxypropyltrimethoxysilane, heat up, mix, and keep the temperature at 65℃ for 14h under a nitrogen atmosphere. After the reaction is completed, filter, wash with deionized water and anhydrous ethanol, and dry to obtain epoxidized titanium dioxide.

[0047] S2. Add 110 mL of tetrahydrofuran, 10 g of carboxylated nitrile rubber, and 2 g of epoxidized titanium dioxide to reactor B, disperse evenly, and maintain the temperature at 20 °C for 9 h under a nitrogen atmosphere. After the reaction is completed, filter, wash with ethyl acetate, and dry to obtain modified nitrile rubber.

[0048] Example 3

[0049] A method for preparing modified nitrile butadiene rubber includes the following steps:

[0050] S1. Add 10g of nano titanium dioxide and 180mL of anhydrous ethanol to reaction vessel A. After dispersing evenly, add 1.6g of γ-glycidyl etheroxypropyltrimethoxysilane, heat up, mix, and keep the temperature at 70℃ for 12h under a nitrogen atmosphere. After the reaction is completed, filter, wash with deionized water and anhydrous ethanol, and dry to obtain epoxidized titanium dioxide.

[0051] S2. Add 120 mL of tetrahydrofuran, 10 g of carboxylated nitrile rubber, and 2.5 g of epoxidized titanium dioxide to reactor B, disperse evenly, and keep the reaction at 35 °C for 8 h under a nitrogen atmosphere. After the reaction is completed, filter, wash with ethyl acetate, and dry to obtain modified nitrile rubber.

[0052] Example 4

[0053] A method for preparing a modified fiber additive includes the following steps:

[0054] Step (1): Place 10g of aramid fiber in 80mL of ethyl acetate, heat, control the temperature at 80℃, keep warm for 1h, cool, add 0.5g of 1,8-diisocyanate, mix, control the temperature at 10℃, keep warm for 30h, after the reaction is complete, filter, wash with saturated sodium carbonate solution, dry, and obtain isocyanate-modified aramid fiber.

[0055] Step (2): Mix 1g of acyl chloride multi-walled carbon nanotubes and 180mL of triethylenetetramine, heat, and keep warm at 115℃ for 48h in a nitrogen atmosphere. After the reaction is completed, distill under reduced pressure, wash with methanol, and dry to obtain aminated multi-walled carbon nanotubes.

[0056] Step (3): Mix 300 mL of N,N-dimethylformamide, 10 g of isocyanate-modified aramid fiber, and 5 g of aminated multi-walled carbon nanotubes evenly, heat, control the temperature at 80 °C, keep warm for 4 h, after the reaction is completed, distill under reduced pressure, wash with anhydrous ethanol, dry, and obtain modified fiber additive.

[0057] Example 5

[0058] A method for preparing a modified fiber additive includes the following steps:

[0059] Step (1): Place 10g of aramid fiber in 95mL of ethyl acetate, heat, control the temperature at 82℃, keep warm for 1h, cool, add 0.8g of 1,8-diisocyanate, mix, control the temperature at 25℃, keep warm for 28h, after the reaction is complete, filter, wash with saturated sodium carbonate solution, dry, and obtain isocyanate-modified aramid fiber.

[0060] Step (2): Mix 1g of acyl chloride multi-walled carbon nanotubes and 200mL of triethylenetetramine, heat, and keep warm at 120℃ for 45h in a nitrogen atmosphere. After the reaction is completed, distill under reduced pressure, wash with methanol, and dry to obtain aminated multi-walled carbon nanotubes.

[0061] Step (3): Mix 320 mL of N,N-dimethylformamide, 10 g of isocyanate-modified aramid fiber, and 6 g of aminated multi-walled carbon nanotubes evenly, heat, control the temperature at 85 °C, keep warm for 3.5 h, after the reaction is completed, distill under reduced pressure, wash with anhydrous ethanol, dry, and obtain modified fiber additive.

[0062] Example 6

[0063] A method for preparing a modified fiber additive includes the following steps:

[0064] Step (1): Place 10g of aramid fiber in 105mL of ethyl acetate, heat, control the temperature at 85℃, keep warm for 1h, cool, add 1g of 1,8-diisocyanate, mix, control the temperature at 35℃, keep warm for 24h, after the reaction is complete, filter, wash with saturated sodium carbonate solution, dry, and obtain isocyanate-modified aramid fiber.

[0065] Step (2): Mix 1g of acyl chloride multi-walled carbon nanotubes and 210mL of triethylenetetramine, heat, and keep warm at 125℃ for 42h in a nitrogen atmosphere. After the reaction is completed, distill under reduced pressure, wash with methanol, and dry to obtain aminated multi-walled carbon nanotubes.

[0066] Step (3): Mix 350 mL of N,N-dimethylformamide, 10 g of isocyanate-modified aramid fiber, and 8 g of aminated multi-walled carbon nanotubes evenly, heat, control the temperature at 90 °C, keep warm for 3 h, after the reaction is completed, distill under reduced pressure, wash with anhydrous ethanol, dry, and obtain modified fiber additive.

[0067] Example 7

[0068] A method for preparing a nanoparticle-modified nitrile rubber composite material includes the following steps:

[0069] 100g of nitrile rubber was placed in a two-roll mill and milled at 45℃ for 6 minutes. Then, 2g of stearic acid, 10g of modified nitrile rubber, 5g of modified fiber additive, 3g of activator, and 0.3g of accelerator were added sequentially. After thorough mixing, 1.5g of sulfur (a vulcanizing aid) and 0.5g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then compounded at 55℃, 35 r / min, and for 40 minutes. After thorough mixing, the mixture was cooled and allowed to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at 10MPa and 165℃ for the specified vulcanization time (T0). 90 After 2 minutes, the material was discharged to obtain nanoparticle-modified nitrile rubber composite material.

[0070] The modified nitrile rubber was prepared using the same method as the modified nitrile rubber in Example 1, and the modified fiber additive was prepared using the same method as the modified fiber additive in Example 4.

[0071] Example 8

[0072] A method for preparing a nanoparticle-modified nitrile rubber composite material includes the following steps:

[0073] 100g of nitrile rubber was placed in a two-roll mill and milled at 50℃ for 5 minutes. Then, 3g of stearic acid, 12g of modified nitrile rubber, 6g of modified fiber additive, 4g of activator, and 0.4g of accelerator were added sequentially. After thorough mixing, 1.8g of sulfur (a vulcanizing aid) and 0.6g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then compounded at 60℃, 40 r / min, and for 35 minutes. After thorough mixing, the mixture was cooled and allowed to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at 12 MPa and 170℃ for the specified vulcanization time (T0). 90 After 2 minutes, the material was discharged to obtain nanoparticle-modified nitrile rubber composite material.

[0074] The modified nitrile rubber was prepared using the same method as the modified nitrile rubber in Example 2, and the modified fiber additive was prepared using the same method as the modified fiber additive in Example 5.

[0075] Example 9

[0076] A method for preparing a nanoparticle-modified nitrile rubber composite material includes the following steps:

[0077] 100g of nitrile rubber was placed in a two-roll mill and milled at 50℃ for 5 minutes. Then, 3.5g of stearic acid, 18g of modified nitrile rubber, 7g of modified fiber additive, 5g of activator, and 0.5g of accelerator were added sequentially. After thorough mixing, 2.2g of sulfur (a vulcanizing aid) and 0.8g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then compounded at 60℃, 40 r / min, and for 35 minutes. After thorough mixing, the mixture was cooled and allowed to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at 12MPa and 170℃ for the specified vulcanization time (T0). 90 After 2 minutes, the material was discharged to obtain nanoparticle-modified nitrile rubber composite material.

[0078] The modified nitrile rubber was prepared using the same method as the modified nitrile rubber in Example 2, and the modified fiber additive was prepared using the same method as the modified fiber additive in Example 5.

[0079] Example 10

[0080] A method for preparing a nanoparticle-modified nitrile rubber composite material includes the following steps:

[0081] 100g of nitrile rubber was placed in a two-roll mill and milled at 55℃ for 4 minutes. Then, 4g of stearic acid, 20g of modified nitrile rubber, 9g of modified fiber additive, 6g of activator, and 0.6g of accelerator were added sequentially. After thorough mixing, 2.5g of sulfur (a vulcanizing aid) and 1g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then kneaded at 65℃, 45 r / min for 30 minutes. After thorough mixing, the mixture was cooled and left to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at a pressure of 15 MPa and a temperature of 175℃ for the specified vulcanization time (T0). 90 After 2 minutes, the material was discharged to obtain nanoparticle-modified nitrile rubber composite material.

[0082] The modified nitrile rubber was prepared using the same method as the modified nitrile rubber in Example 3, and the modified fiber additive was prepared using the same method as the modified fiber additive in Example 6.

[0083] Comparative Example 1

[0084] A method for preparing a nitrile rubber composite material includes the following steps:

[0085] 100g of nitrile rubber was placed in a two-roll mill and milled at 50℃ for 5 minutes. Then, 3.5g of stearic acid, 15g of carboxylated nitrile rubber, 3g of nano-titanium dioxide, 7g of modified fiber additive, 5g of activator, and 0.5g of accelerator were added sequentially. After thorough mixing, 2.2g of sulfur (a vulcanizing aid) and 0.8g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then compounded at 60℃, 40 r / min, and for 35 minutes. After thorough mixing, the mixture was cooled and allowed to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at 12MPa and 170℃ for the specified vulcanization time (T0). 90 After 2 minutes, discharge the material to obtain a nitrile rubber composite material.

[0086] The preparation method of the modified fiber additive is the same as that of the modified fiber additive in Example 5.

[0087] Comparative Example 2

[0088] A method for preparing a nitrile rubber composite material includes the following steps:

[0089] 100g of nitrile rubber was placed in a two-roll mill and milled at 50℃ for 5 minutes. Then, 3.5g of stearic acid, 18g of modified nitrile rubber, 2.6g of acyl chloride multi-walled carbon nanotubes, 4.4g of aramid fiber, 5g of activator, and 0.5g of accelerator were added sequentially. After mixing thoroughly, 2.2g of sulfur (a vulcanizing aid) and 0.8g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and... (the text abruptly ends here, so the translation stops as well.) The mixture consists of magnesium oxide and an accelerator composed of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture is then compounded at 60°C, 40 r / min, and for 35 min. After homogeneous compounding, it is cooled and left to stand for 24 h before vulcanization in a flat vulcanizing machine at 12 MPa, 170°C, and for the specified time (process positive vulcanization time T). 90 After 2 minutes, discharge the material to obtain a nitrile rubber composite material.

[0090] The modified nitrile rubber was prepared using the same method as the modified nitrile rubber in Example 2.

[0091] Comparative Example 3

[0092] A method for preparing a nitrile rubber composite material includes the following steps:

[0093] Place 100g of nitrile rubber in a two-roll mill, control the temperature at 50℃, and mill for 5 minutes. Then, add 3.5g of stearic acid, 15g of carboxylated nitrile rubber, 3g of nano-titanium dioxide, 2.6g of acyl chloride multi-walled carbon nanotubes, 4.4g of aramid fiber, 5g of activator, and 0.5g of accelerator in sequence. After mixing evenly, add 2.2g of sulfur (a vulcanizing aid) and 0.8g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant). The activator is prepared in a mass ratio of 2:1. The mixture consists of zinc oxide and magnesium oxide, and the accelerator is composed of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a mass ratio of 1:1. The mixture is then compounded at 60℃, 40 r / min, and for 35 min. After uniform compounding, it is cooled and left to stand for 24 h before vulcanization in a flat vulcanizing machine at a pressure of 12 MPa, a temperature of 170℃, and a vulcanization time of T (the optimal vulcanization time). 90 After 2 minutes, discharge the material to obtain a nitrile rubber composite material.

[0094] Comparative Example 4

[0095] A method for preparing a nitrile rubber composite material includes the following steps:

[0096] 100g of nitrile rubber was placed in a two-roll mill and milled at 50℃ for 5 minutes. Then, 3.5g of stearic acid, 18g of carboxylated nitrile rubber, 7g of aramid fiber, 5g of activator, and 0.5g of accelerator were added sequentially. After thorough mixing, 2.2g of sulfur (a vulcanizing aid) and 0.8g of 4,4'-di(phenylisopropyl)diphenylamine (an antioxidant) were added. The activator consisted of zinc oxide and magnesium oxide in a 2:1 mass ratio, and the accelerator consisted of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a 1:1 mass ratio. The mixture was then compounded at 60℃, 40 r / min, and for 35 minutes. After thorough mixing, the mixture was cooled and allowed to stand for 24 hours. Finally, it was vulcanized in a flat vulcanizing mill at 12MPa and 170℃ for the specified vulcanization time (T0). 90 After 2 minutes, discharge the material to obtain a nitrile rubber composite material.

[0097] The preparation method of acyl chloride multi-walled carbon nanotubes in the embodiments and comparative examples of this invention is as follows: Carboxylated multi-walled carbon nanotubes, thionyl chloride, and N,N-dimethylformamide are mixed evenly in a mass ratio of 1:200:80. The mixture is heated in a nitrogen atmosphere, and the temperature is controlled at 75°C for 24 hours. After the reaction is completed, the mixture is distilled under reduced pressure, washed with tetrahydrofuran, and dried to obtain acyl chloride multi-walled carbon nanotubes.

[0098] The carboxylated multi-walled carbon nanotubes used in the embodiments and comparative examples of this invention were purchased from Beijing Deco Island Gold Technology Co., Ltd., with a diameter <8nm and a length of 10-30μm; the carboxylated nitrile butadiene rubber (XNBR) was purchased from Lanxess Chemical (China) Co., Ltd., model [model number missing]. Nano-titanium dioxide was purchased from Xuancheng Jingrui New Materials Co., Ltd., model JR05, with an average particle size of 5nm; aramid fiber was purchased from Heilongjiang Hongyu Short Fiber New Materials Co., Ltd., brand RAF-3; nitrile rubber was purchased from Zhenjiang Nandi Chemical Co., Ltd., brand NANCAR1051; other undisclosed reagents were commercially available.

[0099] The nitrile rubber composites prepared in Examples 7-10 and Comparative Examples 1-4 were used as samples for corresponding tests. The samples correspond to samples 1-8 respectively. The test methods and test results are shown below:

[0100] (1) Mechanical property test: The tensile properties of the samples were tested using a Z005 universal electronic tensile testing machine manufactured by Zwick Company. The test standard was in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", with a temperature of 25℃, a load of 1000N, a tensile rate of 500mm / min, and a dumbbell-shaped sample. Each group was tested three times and the average value was taken.

[0101] The test results are shown in Table 1:

[0102] Table 1

[0103]

[0104]

[0105] As can be seen from the test results in Table 1, samples 1-4 exhibit excellent mechanical properties, with sample 3 achieving a tensile strength of 24.5 MPa and an elongation at break of 617.4%. This is mainly due to the introduction of nanoparticles, nano-titanium dioxide, multi-walled carbon nanotubes, and aramid fibers. After modification, the dispersibility is improved, and the raw materials exhibit excellent compatibility. Through synergistic effects, these materials endow the nitrile rubber composite with excellent mechanical properties, including superior tensile strength and elongation at break.

[0106] (2) Aging resistance test: The samples were placed in a UV aging test chamber for 96 hours of aging treatment. The UV aging was performed using a xenon lamp with a power of 35W. After the treatment, the samples were taken out and subjected to the same tensile property test. Each group was tested three times and the average value was taken. The samples were also subjected to the same tensile property test in a thermal aging test chamber according to the national standard GB / T3512-2001. The aging temperature was 100℃ and the thermo-oxidative aging time was 96 hours. Each group was tested three times and the average value was taken.

[0107] The test results are shown in Table 2:

[0108] Table 2

[0109]

[0110]

[0111] As shown in Table 2, samples 1-4 exhibit excellent aging resistance, retaining good mechanical properties even after heat aging and UV aging treatments. Sample 3 maintains a tensile strength of 22.4 MPa and an elongation at break of 534.3% after heat aging treatment, and a tensile strength of 23.0 MPa and an elongation at break of 546.9% after UV aging treatment. The introduced nanoparticles demonstrate excellent heat resistance and UV aging resistance, effectively improving the aging resistance of nitrile rubber composites.

[0112] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A nanoparticle-modified nitrile rubber composite material, characterized in that: It is made from the following components in parts by weight: 100 parts of nitrile rubber, 10-20 parts of modified nitrile rubber, 5-9 parts of modified fiber additives, 2-4 parts of stearic acid, 3-6 parts of activator, 0.5-1 part of antioxidant, 0.3-0.6 parts of accelerator, and 1.5-2.5 parts of vulcanizing aid; The modified nitrile rubber is obtained by reacting carboxylated nitrile rubber with epoxidized titanium dioxide; The modified fiber additive is obtained by modifying aramid fibers with multi-walled carbon nanotubes; The activator is composed of zinc oxide and magnesium oxide in a mass ratio of 2:1; The antioxidant is 4,4'-bis(phenylisopropyl)diphenylamine; The accelerator is composed of 2-mercaptobenzothiazole and N-tert-butyl-2-benzothiazole sulfenamide in a mass ratio of 1:1; The vulcanization aid is sulfur.

2. The nanoparticle-modified nitrile rubber composite material according to claim 1, characterized in that: The preparation method of the modified nitrile rubber includes the following steps: S1. Add nano-titanium dioxide and anhydrous ethanol to reaction vessel A, disperse evenly, add γ-glycidyl etheroxypropyltrimethoxysilane, heat up, mix, and keep the temperature at 60-70℃ for 12-15 hours under a nitrogen atmosphere. After the reaction is completed, filter, wash with deionized water and anhydrous ethanol, and dry to obtain epoxidized titanium dioxide. S2. Add tetrahydrofuran, carboxylated nitrile rubber, and epoxidized titanium dioxide to reactor B, disperse evenly, and maintain the temperature at 10-35℃ for 8-10 hours under a nitrogen atmosphere. After the reaction is completed, filter, wash with ethyl acetate, and dry to obtain modified nitrile rubber.

3. The nanoparticle-modified nitrile rubber composite material according to claim 2, characterized in that: The addition ratio of tetrahydrofuran, carboxylated nitrile rubber, and epoxidized titanium dioxide in S2 is (100-120) mL: 10 g: (1-2.5) g.

4. The nanoparticle-modified nitrile rubber composite material according to claim 1, characterized in that: The preparation method of the modified fiber additive includes the following steps: Step (1): Place the aramid fiber in ethyl acetate, heat it, control the temperature at 80-85℃, keep it warm for 1 hour, cool it, add 1,8-diisocyanate, mix it, control the temperature at 10-35℃, keep it warm for 24-30 hours, after the reaction is complete, filter it, wash it with saturated sodium carbonate solution, dry it, and obtain isocyanate-treated aramid fiber. Step (2): Mix acyl chloride multi-walled carbon nanotubes and triethylenetetramine, heat, and keep warm at 115-125℃ for 42-48h in a nitrogen atmosphere. After the reaction is completed, distill under reduced pressure, wash with methanol, and dry to obtain aminated multi-walled carbon nanotubes. Step (3): Mix N,N-dimethylformamide, isocyanate-modified aramid fiber, and aminated multi-walled carbon nanotubes evenly, heat, control the temperature at 80-90℃, keep warm for 3-4 hours, after the reaction is completed, distill under reduced pressure, wash with anhydrous ethanol, and dry to obtain modified fiber additive.

5. The nanoparticle-modified nitrile rubber composite material according to claim 4, characterized in that: In step (1), the addition ratio of aramid fiber, ethyl acetate, and 1,8-diisocyanate is (80-105) mL: 10 g: (0.5-1) g.

6. The nanoparticle-modified nitrile rubber composite material according to claim 4, characterized in that: In step (2), the addition ratio of acyl chloride multi-walled carbon nanotubes and triethylenetetramine is 1g:(180-210)mL.

7. The nanoparticle-modified nitrile rubber composite material according to claim 4, characterized in that: In step (3), the addition ratio of N,N-dimethylformamide, isocyanate-modified aramid fiber, and aminated multi-walled carbon nanotubes is (300-350) mL: 10 g: (5-8) g.

8. A method for preparing nanoparticle-modified nitrile rubber composite material as described in any one of claims 1-7, characterized in that: Includes the following steps: Nitrile rubber was placed in a two-roll mill and the temperature was controlled at 45-55℃ for 4-6 minutes. Stearic acid, modified nitrile rubber, modified fiber additives, activators, accelerators, vulcanizing agents, and antioxidants were added in sequence and mixed evenly. After mixing evenly, the mixture was cooled and left to stand for 24 hours. Then, it was vulcanized in a flat vulcanizing mill and discharged to obtain nanoparticle modified nitrile rubber composite material.

9. The method for preparing a nanoparticle-modified nitrile rubber composite material according to claim 8, characterized in that: The mixing temperature is 55-65℃, the rotation speed is 35-45r / min, and the mixing time is 30-40min.

10. The method for preparing a nanoparticle-modified nitrile rubber composite material according to claim 8, characterized in that: During the vulcanization process, the vulcanization pressure is 10-15 MPa and the vulcanization temperature is 165-175℃.

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