A method for promoting dispersion of helical nanocarbon fibers in rubber and applications, a rubber composite

Abstract

The application provides a method for promoting dispersion of helical nanometer carbon fibers in rubber and application and a rubber composite material, and belongs to the technical field of rubber.The helical nanometer carbon fibers and other one-dimensional nanometer carbon fillers are modified by using the strong wetting property of ionic liquid, and the hydrophilicity of the helical nanometer carbon fibers and other one-dimensional nanometer carbon fillers is enhanced;white carbon black is added to reduce the interaction between the helical nanometer carbon fibers and other one-dimensional nanometer carbon fillers, and the firm interface combination of the composite powder and rubber is promoted;the helical nanometer carbon fiber / white carbon black composite powder is used in the rubber composite material, compared with the helical nanometer carbon fibers without modification by ionic liquid and the rubber composite material without the helical nanometer carbon fibers, the 300% modulus of elasticity, the tensile strength at break, the tear strength and the wear resistance of the rubber composite material can be improved by 300%, and the compression permanent set rate can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of rubber technology, specifically relating to a method and application for promoting the dispersion of helical carbon nanofibers in rubber, and a rubber composite material. Background Technology

[0002] Rubber composite materials are materials composed of rubber as the matrix and added reinforcing materials, fillers and / or modifying materials. They have excellent comprehensive mechanical and electrical properties and are widely used in various fields.

[0003] Commonly used rubber reinforcing materials are one-dimensional carbon nanofillers, including helical carbon nanofibers, linear carbon fibers, linear carbon nanotubes, and helical carbon nanotubes. Among them, helical carbon nanofibers are a type of carbon nanofiber with a special helical structure. They not only possess the excellent properties of traditional linear carbon nanotubes but also have the advantages brought by their multi-dimensional helical structure. In the rubber matrix, they can entangle and adsorb more rubber molecular chains due to their special helical morphology, thus bringing a better reinforcing effect. However, to realize the performance advantages of helical carbon nanotubes in reinforcing rubber, good dispersion in the rubber matrix is ​​a prerequisite. But due to their special helical structure, they are difficult to disperse in the rubber matrix. At the same time, the dispersibility of other one-dimensional carbon nanofillers in the rubber matrix also needs to be improved. In the existing technology, in order to improve the dispersibility of helical carbon nanofibers, they are combined with latex-like SBR, kneaded with a kneading agent, and then coagulated and dried with a flocculant. However, the flocculant used will remain in the rubber composite material, which is not conducive to improving the mechanical properties of the rubber composite material. Therefore, improving the dispersibility of one-dimensional nano-carbon fillers such as helical carbon nanofibers in rubber matrices, thereby enhancing the mechanical properties of rubber composites, has become a challenge in the existing technology. Summary of the Invention

[0004] The purpose of this invention is to provide a method and application for promoting the dispersion of helical carbon nanofibers in rubber, and a rubber composite material. The method provided by this invention can promote better dispersion of one-dimensional nanocarbon fillers such as helical carbon nanofibers in a rubber matrix, thereby improving the overall performance of the rubber composite material.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for promoting the dispersion of one-dimensional nano-carbon fillers in rubber, comprising the following steps:

[0007] (1) Ionic liquid, water and one-dimensional carbon nanofiller are mixed and modified to obtain ionic liquid modified one-dimensional carbon nanofiller slurry; the one-dimensional carbon nanofiller includes at least one of helical carbon nanofibers, linear carbon fibers, linear carbon nanotubes and helical carbon nanotubes.

[0008] (2) Mix silica and water to obtain silica slurry;

[0009] (3) The ionic liquid modified one-dimensional nano carbon filler slurry obtained in step (1) and the silica slurry obtained in step (2) are mixed and centrifuged and spray-dried to obtain one-dimensional nano carbon filler / silica composite powder.

[0010] Steps (1) and (2) are not in any particular order.

[0011] Preferably, the ionic liquid in step (1) includes at least one of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium ionic liquids, and quaternary phosphine ionic liquids.

[0012] Preferably, in step (1), the mass ratio of ionic liquid to one-dimensional carbon nanofiller is (0.25-2.5):(0.5-5).

[0013] Preferably, the modification time in step (1) is 1 to 3 hours.

[0014] Preferably, in step (3), the mass ratio of one-dimensional nano-carbon filler in the ionic liquid modified one-dimensional nano-carbon filler slurry to silica in the silica slurry is (0.5-5):(45-49.5).

[0015] Preferably, in step (3), the temperature of the centrifugal spray drying is 100-400℃, the speed of the centrifugal spray drying is 10000-24000rpm, and the flow rate of the centrifugal spray drying is 10-100mL / min.

[0016] The present invention also provides a one-dimensional nano-carbon filler / silica composite powder obtained by the method described in the above technical solution.

[0017] This invention also provides the application of the one-dimensional nano-carbon filler / silica composite powder described in the above technical solution as a rubber reinforcing filler.

[0018] The present invention also provides a rubber composite material, comprising, by weight, the following components: 100 parts of natural rubber and / or EPDM rubber, 0.3-3 parts of softening plasticizer, 2-7 parts of vulcanizing activator, 0.5-2.5 parts of antioxidant, 1.5-6.5 parts of accelerator, 1-3 parts of vulcanizing agent, 3-5 parts of activating dispersant, and 40-80 parts of one-dimensional nano-carbon filler / silica composite powder, wherein the one-dimensional nano-carbon filler / silica composite powder is the one-dimensional nano-carbon filler / silica composite powder described in the above technical solution.

[0019] Preferably, the antioxidant includes at least one of antioxidant 4010NA, antioxidant 264, antioxidant 4020, antioxidant MB, and antioxidant RD.

[0020] This invention provides a method for promoting the dispersion of one-dimensional carbon nanofillers in rubber, comprising the following steps: (1) mixing an ionic liquid, water and one-dimensional carbon nanofillers, and modifying them to obtain an ionic liquid modified one-dimensional carbon nanofiller slurry; the one-dimensional carbon nanofiller includes at least one of helical carbon nanofibers, linear carbon fibers, linear carbon nanotubes and helical carbon nanotubes; (2) mixing silica and water to obtain silica slurry; (3) mixing the ionic liquid modified one-dimensional carbon nanofiller slurry obtained in step (1) and the silica slurry obtained in step (2), and centrifugally spray-drying them to obtain a one-dimensional carbon nanofiller / silica composite powder; the steps (1) and (2) are not in any particular order. This invention utilizes the strong wettability of ionic liquids to modify one-dimensional carbon nanofillers such as helical carbon nanofibers, enhancing their hydrophilicity. The addition of silica reduces the interaction between the helical carbon nanofibers and other one-dimensional carbon nanofillers, promoting a strong interfacial bond between the one-dimensional carbon nanofiller / silica composite powder and rubber. After being added to the rubber matrix, it exhibits good dispersibility, thereby improving the overall performance of the rubber composite material. The results of the embodiments show that, compared with rubber composites without helical carbon nanofiber modification or without the addition of helical carbon nanofibers, using the helical carbon nanofiber / silica composite powder prepared according to this invention in rubber composites can increase the 300% tensile stress, tensile strength at break, tear strength, and abrasion resistance of the rubber composite material, while reducing the compression set. Attached Figure Description

[0021] Figure 1 Here is a SEM image of the helical carbon nanofibers in Example 1;

[0022] Figure 2 This is a SEM image of the 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / fumed silica composite powder in Example 1. Detailed Implementation

[0023] This invention provides a method for promoting the dispersion of one-dimensional nano-carbon fillers in rubber, comprising the following steps:

[0024] (1) Mix ionic liquid, water and one-dimensional nano-carbon filler, and modify them to obtain ionic liquid modified one-dimensional nano-carbon filler slurry.

[0025] (2) Mix silica and water to obtain silica slurry;

[0026] (3) The ionic liquid modified one-dimensional nano carbon filler slurry obtained in step (1) and the silica slurry obtained in step (2) are mixed and centrifuged and spray-dried to obtain one-dimensional nano carbon filler / silica composite powder.

[0027] Steps (1) and (2) are not in any particular order.

[0028] This invention involves mixing ionic liquid, water, and one-dimensional nano-carbon filler, and then modifying the mixture to obtain an ionic liquid-modified one-dimensional nano-carbon filler slurry.

[0029] In this invention, the ionic liquid preferably includes at least one of imidazole ionic liquids, pyridine ionic liquids, quaternary ammonium ionic liquids, and quaternary phosphine ionic liquids, more preferably at least one of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylpyridine tetrafluoroborate, triethylmethylammonium tetrafluoroborate, and tricyclohexylphosphine tetrafluoroborate, and most preferably 1-butyl-3-methylimidazolium tetrafluoroborate. This invention utilizes the extremely strong wettability of ionic liquids to modify one-dimensional nano-carbon fillers such as helical carbon nanofibers, enhancing their hydrophilicity, improving the dispersibility of one-dimensional nano-carbon filler / fumed silica composite powder in a rubber matrix, and improving the overall performance of the rubber composite material. The selection of the above-mentioned ionic liquids in this invention can further improve the dispersibility of one-dimensional nano-carbon filler / fumed silica composite powder in a rubber matrix.

[0030] In this invention, the one-dimensional carbon nanofiller includes at least one of helical carbon nanofibers, linear carbon fibers, linear carbon nanotubes, and helical carbon nanotubes.

[0031] This invention does not impose any special limitation on the size of the one-dimensional carbon nanofiller; it can be selected according to actual needs. In the embodiments of this invention, the diameter of the spiral carbon nanofiber is 30–100 nm; the thread pitch of the spiral carbon nanofiber is 50–140 nm; and the length of the spiral carbon nanofiber is 1–50 μm. This invention does not impose any special limitation on the source of the spiral carbon nanofiber; commercially available products well known to those skilled in the art can be used.

[0032] In this invention, the preferred mass ratio of the ionic liquid to the one-dimensional carbon nanofiller is (0.25–2.5):(0.5–5), more preferably (0.5–2):(0.5–5), and even more preferably (1–1.5):(0.5–5). This invention controls the mass ratio of the ionic liquid to the one-dimensional carbon nanofiller within the above range. If the ionic liquid content is too low, it cannot fully wet the one-dimensional carbon nanofiller, resulting in uneven dispersion. Conversely, if the ionic liquid content is too high, it will reduce the crosslinking density of the rubber, causing a decrease in the mechanical properties of the rubber. In this invention, the ionic liquid itself has advantages such as extremely low vapor pressure, low volatility, good thermal stability, and environmental friendliness. Only a small amount needs to be added to achieve effective modification of the one-dimensional carbon nanofiller.

[0033] The present invention does not have a special limitation on the amount of water used, as long as the ionic liquid and the one-dimensional nano-carbon filler are fully mixed and dispersed.

[0034] In this invention, the preferred method for mixing the ionic liquid, water, and one-dimensional carbon nanofiller is to mix the ionic liquid and water, and then add the one-dimensional carbon nanofiller.

[0035] In this invention, the mixing of the ionic liquid and water is preferably carried out under stirring conditions; the mixing rate of the ionic liquid and water is preferably 400 to 1600 rpm; and the mixing time of the ionic liquid and water is preferably 2 to 24 hours.

[0036] In this invention, the modification is preferably performed under ultrasonic conditions; the modification time is preferably 1 to 3 hours. In embodiments of this invention, the modification time can specifically be 1 hour, 2 hours, or 3 hours. This invention does not impose any special limitation on the ultrasonic power; ultrasonic power well-known to those skilled in the art can be used. By controlling the modification method and time within the above-mentioned range, this invention enables more thorough modification.

[0037] This invention involves mixing silica and water to obtain silica slurry.

[0038] This invention does not impose any special limitation on the particle size of the silica; it can be selected according to actual needs. In the embodiments of this invention, the primary structure particle size of the silica is 7–120 nm; the secondary structure particle size of the silica is 0.5–50 μm.

[0039] The present invention does not have a special limitation on the amount of water used, as long as it is sufficient to fully disperse the silica.

[0040] In this invention, the mixing of silica and water is preferably carried out under stirring conditions; the stirring rate is preferably 400-1600 rpm; and the stirring time is preferably 2-24 h.

[0041] After obtaining the ionic liquid modified one-dimensional nano-carbon filler slurry and the silica slurry, the present invention mixes the ionic liquid modified one-dimensional nano-carbon filler slurry and the silica slurry, and performs centrifugal spray drying to obtain one-dimensional nano-carbon filler / silica composite powder.

[0042] In this invention, the preferred mass ratio of one-dimensional nano-carbon filler in the ionic liquid-modified one-dimensional nano-carbon filler slurry to silica in the silica slurry is (0.5–5):(45–49.5). In this invention, the silica reduces the interaction between one-dimensional nano-carbon fillers such as helical carbon nanofibers, promotes a strong interfacial bond between the one-dimensional nano-carbon filler / silica composite powder and rubber, and improves the overall performance of the rubber composite material. By controlling the mass ratio of one-dimensional nano-carbon filler to silica within the above range, this invention can further improve the dispersibility of the one-dimensional nano-carbon filler / silica composite powder in the rubber matrix.

[0043] In this invention, the mixing of the ionic liquid modified one-dimensional nano-carbon filler slurry and the silica slurry is preferably carried out under stirring conditions; the stirring rate is preferably 400-1600 rpm; and the stirring time is preferably 2-24 h.

[0044] In this invention, the preferred temperature for centrifugal spray drying is 100–400°C. In embodiments of this invention, the specific temperature for centrifugal spray drying can be 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, or 400°C. In this invention, if the centrifugal spray drying temperature is too low, the composite powder will have an excessively high moisture content, making it unusable directly. Conversely, if the centrifugal spray drying temperature is too high, the composite powder will lose its surface activity and the ionic liquid will decompose.

[0045] In this invention, the rotational speed of the centrifugal spray dryer is preferably 10,000 to 24,000 rpm. In embodiments of this invention, the rotational speed of the centrifugal spray dryer may specifically be 10,000 rpm, 11,000 rpm, 12,000 rpm, 13,000 rpm, 14,000 rpm, 15,000 rpm, 16,000 rpm, 17,000 rpm, 18,000 rpm, 19,000 rpm, 20,000 rpm, 21,000 rpm, 22,000 rpm, 23,000 rpm, or 24,000 rpm.

[0046] In this invention, the flow rate of the centrifugal spray drying is preferably 10-100 mL / min. In embodiments of this invention, the flow rate of the centrifugal spray drying can specifically be 10 mL / min, 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, or 100 mL / min. In this invention, excessively low rotation speed and excessively high flow rate in the centrifugal spray drying will result in excessively large particle size of the composite powder, affecting rubber properties; conversely, excessively high rotation speed and excessively low flow rate will result in excessively low yield of the composite powder and waste of energy.

[0047] This invention employs centrifugal spray drying to rapidly dry one-dimensional nano-carbon filler / silica slurry, obtaining uniform and fine composite powders while avoiding sedimentation, stratification, and agglomeration. This invention does not impose any specific limitations on the equipment used for centrifugal spray drying; any spray drying equipment well-known to those skilled in the art can be used. In embodiments of this invention, the centrifugal spray drying equipment can be an LPG-5 centrifugal spray dryer.

[0048] The method of this invention has a simple process flow, is suitable for large-scale production applications, and can give full play to the super reinforcing effect of one-dimensional nano-carbon fillers such as spiral nano-carbon fibers. It can achieve a significant improvement in the comprehensive mechanical properties of natural rubber / EPDM rubber composites by adding a small amount of one-dimensional nano-carbon fillers such as spiral nano-carbon fibers.

[0049] The present invention also provides a one-dimensional nano-carbon filler / silica composite powder obtained by the method described in the above technical solution.

[0050] In this invention, the one-dimensional nano-carbon filler is uniformly embedded between the silica particles in the one-dimensional nano-carbon filler / silica composite powder.

[0051] In this invention, the particle size of the one-dimensional nano-carbon filler / silica composite powder is preferably 1–55 μm. By controlling the particle size of the one-dimensional nano-carbon filler / silica composite powder within the above range, this invention can further improve the comprehensive performance of the rubber composite material.

[0052] This invention also provides the application of the one-dimensional nano-carbon filler / silica composite powder described in the above technical solution as a rubber reinforcing filler.

[0053] The present invention does not have any particular limitation on the type of rubber, and any type of rubber well known to those skilled in the art can be used.

[0054] The present invention does not impose any special limitations on the operation of the application, and any technical solution known to those skilled in the art can be used.

[0055] The present invention also provides a rubber composite material, comprising, by weight, the following components: 100 parts of natural rubber and / or EPDM rubber, 0.3-3 parts of softening plasticizer, 2-7 parts of vulcanizing activator, 0.5-2.5 parts of antioxidant, 1.5-6.5 parts of accelerator, 1-3 parts of vulcanizing agent, 3-5 parts of activating dispersant, and 40-80 parts of one-dimensional nano-carbon filler / silica composite powder, wherein the one-dimensional nano-carbon filler / silica composite powder is the one-dimensional nano-carbon filler / silica composite powder of the above-mentioned technical solution.

[0056] Unless otherwise specified, the present invention does not have any special limitations on the source of each component, and commercially available products well known to those skilled in the art can be used.

[0057] The rubber composite material provided by this invention comprises 100 parts by weight of natural rubber and / or ethylene propylene diene monomer (EPDM) rubber. When the rubber composite material comprises natural rubber and EPDM rubber, this invention does not impose a specific limitation on the ratio of the natural rubber and EPDM rubber, and any ratio can be used.

[0058] The rubber composite material provided by the present invention comprises 0.3 to 3 parts of a softening plasticizer, with 100 parts by weight of natural rubber and / or EPDM rubber. In the embodiments of the present invention, the amount of the softening plasticizer may specifically be 0.3 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, or 3 parts.

[0059] In this invention, the softening plasticizer is preferably stearic acid.

[0060] The rubber composite material provided by the present invention comprises 2 to 7 parts of vulcanizing activator, with 100 parts by weight of natural rubber and / or EPDM rubber. In the embodiments of the present invention, the amount of vulcanizing activator may specifically be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or 7 parts.

[0061] In this invention, the sulfidation activator is preferably zinc oxide. This invention does not impose any particular limitation on the particle size of the zinc oxide; commercially available products well-known to those skilled in the art can be used.

[0062] The rubber composite material provided by the present invention comprises 0.5 to 2.5 parts of antioxidant, with 100 parts by weight of natural rubber and / or EPDM rubber. In the embodiments of the present invention, the amount of antioxidant may specifically be 0.5 parts, 1 part, 1.5 parts, 2 parts, or 2.5 parts.

[0063] In this invention, the antioxidant preferably includes at least one of antioxidant 4010NA, antioxidant 264, antioxidant 4020, antioxidant MB, and antioxidant RD.

[0064] The rubber composite material provided by the present invention comprises 1.5 to 6.5 parts of accelerator, with 100 parts by weight of natural rubber and / or EPDM rubber. In the embodiments of the present invention, the amount of accelerator may specifically be 1.5 parts, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or 6.5 parts.

[0065] In this invention, the accelerator preferably includes at least one of accelerator CZ, accelerator NS, accelerator AZ, accelerator BSO, accelerator ARZ, accelerator DIBS, accelerator TMTD, accelerator TMTM, accelerator PMTM, accelerator TETD, accelerator PTD and accelerator TMTT, and more preferably includes accelerator CZ and accelerator TMTD.

[0066] In this invention, when the accelerator includes accelerator CZ and accelerator TMTD, the mass ratio of accelerator CZ to accelerator TMTD is preferably (1-3):1, more preferably 2:1.

[0067] The rubber composite material provided by the present invention comprises 1 to 3 parts of vulcanizing agent, with 100 parts by weight of natural rubber and / or EPDM rubber. In the embodiments of the present invention, the amount of vulcanizing agent may specifically be 1 part, 2 parts, or 3 parts.

[0068] In this invention, the vulcanizing agent is preferably sulfur.

[0069] The rubber composite material provided by the present invention comprises 3 to 5 parts of an activating dispersant, with 100 parts by weight of natural rubber and / or EPDM rubber. In embodiments of the present invention, the amount of the activating dispersant may specifically be 3 parts, 4 parts, or 5 parts.

[0070] In this invention, the activating dispersant is preferably polyethylene glycol, more preferably polyethylene glycol 4000.

[0071] With 100 parts by weight of natural rubber and / or EPDM rubber, the rubber composite material provided by the present invention includes 40-80 parts of one-dimensional nano-carbon filler / silica composite powder. In the embodiments of the present invention, the amount of the one-dimensional nano-carbon filler / silica composite powder can be specifically 40 parts, 50 parts, 60 parts, 70 parts, or 80 parts.

[0072] This invention controls the composition and dosage of each component in rubber composite materials, thereby further improving the overall performance of rubber composite materials.

[0073] The present invention does not impose any particular limitation on the preparation method of the rubber composite material, and any preparation method of rubber composite material well known to those skilled in the art can be used.

[0074] In this invention, when natural rubber and EPDM rubber are included, the preferred method for preparing the rubber composite material is as follows: after plasticizing the natural rubber, it is wrapped around a roller, then EPDM rubber is added and wrapped around the roller again, followed by the addition of a softening plasticizer, a vulcanizing activator, an antioxidant, an accelerator, and an activating dispersant for a first mixing, and finally one-dimensional nano-carbon filler / silica composite powder and a vulcanizing agent are added, followed by a second mixing, thin-passing, triangular wrapping, sheeting, and vulcanization to obtain the rubber composite material.

[0075] In this invention, the plasticizing temperature is preferably 20-40°C, more preferably 30°C; the plasticizing time is preferably 5-15 min, more preferably 10 min.

[0076] In this invention, the temperature of the first mixing is preferably 20-30°C, more preferably 25°C; the time of the first mixing is preferably 1-10 min, more preferably 5 min.

[0077] In this invention, the temperature of the second mixing is preferably 50-60°C, more preferably 55°C; the time of the second mixing is preferably 1-10 min, more preferably 5 min.

[0078] In this invention, the number of thin passes is preferably 5 to 7, more preferably 6.

[0079] In this invention, the number of times the triangular bag is patted is preferably 5 to 7 times, and more preferably 6 times.

[0080] In this invention, the vulcanization temperature is preferably 150-180°C, more preferably 160-170°C; the vulcanization time is preferably 1-10 min, more preferably 5 min.

[0081] By controlling the parameters in the preparation method within the above-mentioned range, this invention can further improve the overall performance of rubber composite materials.

[0082] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0083] Example 1

[0084] A method to promote the dispersion of helical carbon nanofibers in rubber: (1) 1g of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate and water are stirred at 800rpm for 2h using a high-speed stirrer, 2g of helical carbon nanofibers (diameter 30-100nm, thread pitch 50-140nm, length 1-50μm, mass ratio of ionic liquid to helical carbon nanofibers 0.5:1) are added, and ultrasonically vibrated for 2h to obtain ionic liquid modified helical carbon nanofiber slurry;

[0085] (2) Mix 48g of silica (primary structure particle size of 7-120nm and secondary structure particle size of 0.5-50μm) with water and stir at 1000rpm for 2h using a high-speed stirrer to obtain silica slurry.

[0086] (3) While stirring at 1000 rpm, add the ionic liquid modified spiral carbon nanofiber slurry obtained in step (1) to the silica slurry in step (2) (the mass ratio of spiral carbon nanofiber to silica is 2:48), and continue stirring for 6 hours to obtain a spiral carbon nanofiber / silica mixed slurry.

[0087] (4) The spiral carbon nanofiber / silica mixture slurry obtained in step (3) was subjected to high-speed centrifugal spray drying at 50 mL / min, 245 °C and 16000 rpm to obtain 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / silica composite powder (particle size 1-55 μm).

[0088] Example 2

[0089] The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate in Example 1 was replaced with 1-butyl-3-methylpyridine tetrafluoroborate, and all other parameters were the same as in Example 1.

[0090] Example 3

[0091] The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate in Example 1 was replaced with triethylmethylammonium tetrafluoroborate, and all other parameters were the same as in Example 1.

[0092] Example 4

[0093] The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate in Example 1 was replaced with tricyclohexylphosphine tetrafluoroborate, and all other parameters were the same as in Example 1.

[0094] Comparative Example 1

[0095] The ionic liquid in Example 1 was omitted, and unmodified spiral carbon nanofiber / fumed silica composite powder was obtained.

[0096] Comparative Example 2

[0097] Silica.

[0098] The helical carbon nanofibers in Example 1 were observed using scanning electron microscopy, and the SEM images obtained are shown below. Figure 1 As shown; the 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / fumed silica composite powder in Example 1 was observed using scanning electron microscopy, and the SEM images obtained are shown below. Figure 2 As shown. From Figure 1 and Figure 2 As can be seen, unmodified helical carbon nanofibers ， A large number of fibers are tightly intertwined and aggregated into clusters. After being modified by ionic liquid, the spiral carbon nanofibers untangle and are uniformly embedded in the silica in the form of single strands.

[0099] Application Example 1

[0100] A rubber composite material, by weight, is composed of the following components: 60 parts natural rubber, 40 parts EPDM rubber, 1 part stearic acid, 5 parts zinc oxide, 1.5 parts antioxidant 4010NA, 3 parts accelerator CZ, 1.5 parts accelerator TMTD, 4 parts polyethylene glycol 4000, 51 parts 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / fumed silica composite powder from Example 1, and 2 parts sulfur;

[0101] The preparation method of the rubber composite material is as follows: natural rubber is plasticized on a two-roll mill (plasticizing temperature is 30℃, time is 10min), then wrapped around the rolls, followed by the addition of EPDM rubber and then the addition of stearic acid, zinc oxide, antioxidant 4010NA, accelerator CZ, accelerator TMTD and polyethylene glycol 4000 in sequence. After mixing at 25℃ for 5min, 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral nanofiber / fumed silica composite powder is added, followed by sulfur. After mixing at 55℃ for 5min, the mixture is passed through a thin pass 6 times, and then formed into triangular wraps 6 times. Finally, the mixture is sheeted and vulcanized at 160℃ for 5min to obtain the rubber composite material.

[0102] Application Example 2

[0103] The 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / silica composite powder in Application Example 1 was replaced with the spiral carbon nanofiber / silica composite powder in Example 2, and all other parameters were the same as in Application Example 1.

[0104] Application Example 3

[0105] The 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / silica composite powder in Application Example 1 was replaced with the spiral carbon nanofiber / silica composite powder in Example 3, and all other parameters were the same as in Application Example 1.

[0106] Application Example 4

[0107] The 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / silica composite powder in Application Example 1 was replaced with the spiral carbon nanofiber / silica composite powder in Example 4, and all other parameters were the same as in Application Example 1.

[0108] Comparative Application Example 1

[0109] The 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / fumed silica composite powder in Application Example 1 was replaced with the unmodified spiral carbon nanofiber / fumed silica composite powder in Comparative Example 1, and all other parameters were the same as in Application Example 1.

[0110] Comparative Application Example 2

[0111] The 1-butyl-3-methylimidazolium tetrafluoroborate modified spiral carbon nanofiber / silica composite powder in Application Example 1 was replaced with silica in Comparative Example 2, and all other parameters were the same as in Application Example 1.

[0112] The 300% constant elongation stress, tensile strength at break, tear strength, compression set, and relative volumetric wear of the rubber composite materials in Application Examples 1-4 and Comparative Application Examples 1-2 were tested. The 300% constant elongation stress and tensile strength at break were determined using GB / T 528-2009, the tear strength was determined using a right-angled specimen using GB / T 529-2008, the compression set at 25℃ for 24 hours was determined using GB / T 7759.1-2015, and the wear resistance (relative volumetric wear) was determined using GB / T 9867-2008. The results are shown in Table 1.

[0113] Table 1 shows the 300% tensile stress, tensile strength at break, tear strength, compression set, and relative volumetric wear of the rubber composites in Application Examples 1-4 and Comparative Application Examples 1-2.

[0114]

[0115] As shown in Table 1, the ionic liquid-modified helical carbon nanofiber / fumed silica composite powder, when used to reinforce a natural rubber / EPDM rubber blend, exhibits varying degrees of improvement in 300% tensile stress, tensile strength at break, and tear strength, while reducing compression set, compared to rubber samples without ionic liquid modification or without added helical carbon nanofiber. Among these, the 1-butyl-3-methylimidazolium tetrafluoroborate-modified helical carbon nanofiber / fumed silica composite powder shows the most significant effect, effectively overcoming the problem of easy agglomeration of helical carbon nanofiber in rubber, thereby further improving the overall performance of the rubber composite material.

[0116] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for promoting the dispersion of one-dimensional nano-carbon fillers in rubber, comprising the following steps: (1) An ionic liquid, water and one-dimensional carbon nanofiller are mixed and modified to obtain an ionic liquid modified one-dimensional carbon nanofiller slurry; the one-dimensional carbon nanofiller is a spiral carbon nanofiber; the ionic liquid is one of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylpyridine tetrafluoroborate, triethylmethylammonium tetrafluoroborate and tricyclohexylphosphine tetrafluoroborate; the mass ratio of the ionic liquid to the one-dimensional carbon nanofiller is 0.5:1; (2) Mix silica and water to obtain silica slurry; (3) The ionic liquid modified one-dimensional nano carbon filler slurry obtained in step (1) and the silica slurry obtained in step (2) are mixed and centrifuged and spray-dried to obtain one-dimensional nano carbon filler / silica composite powder; the mass ratio of one-dimensional nano carbon filler in the ionic liquid modified one-dimensional nano carbon filler slurry to silica in the silica slurry is 2:

48. The steps (1) and (2) are not in any particular order.

2. The method according to claim 1, characterized in that, The modification time in step (1) is 1~3 hours.

3. The method according to claim 1, characterized in that, In step (3), the temperature of the centrifugal spray drying is 100~400℃, the speed of the centrifugal spray drying is 10000~24000rpm, and the flow rate of the centrifugal spray drying is 10~100mL / min.

4. The one-dimensional nano-carbon filler / silica composite powder obtained by the method according to any one of claims 1 to 3.

5. The application of the one-dimensional nano-carbon filler / silica composite powder according to claim 4 as a rubber reinforcing filler.

6. A rubber composite material, comprising, by weight, the following components: 100 parts of natural rubber and / or EPDM rubber, 0.3-3 parts of softening plasticizer, 2-7 parts of vulcanizing activator, 0.5-2.5 parts of antioxidant, 1.5-6.5 parts of accelerator, 1-3 parts of vulcanizing agent, 3-5 parts of activating dispersant, and 40-80 parts of one-dimensional nano-carbon filler / silica composite powder, wherein the one-dimensional nano-carbon filler / silica composite powder is the one-dimensional nano-carbon filler / silica composite powder as described in claim 4.

7. The rubber composite material according to claim 6, characterized in that, The antioxidant includes at least one of antioxidant 4010NA, antioxidant 264, antioxidant 4020, antioxidant MB, and antioxidant RD.

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