Pyrolytic carbon black fiber, its preparation method and application

Abstract

This invention provides a pyrolytic carbon black fiber, its preparation method, and its application. The pyrolytic carbon black fiber comprises a polyvinylpyrrolidone fiber body and pyrolytic carbon black with an N-acyl amino acid-modified surface dispersed therein. This invention utilizes N-acyl amino acids to clean and modify the surface of the pyrolytic carbon black, and employs fiber dispersion to form a network structure in the modified pyrolytic carbon black, resulting in a larger contact area and better dispersibility.

Description

Technical Field

[0001] This invention relates to the field of pyrolytic carbon black modification and its applications, specifically to a pyrolytic carbon black fiber, its preparation method, and its applications. Background Technology

[0002] With the booming development of the automotive and road transportation industries, the demand for tires is increasing daily, and the amount of waste tires is also rising accordingly. On the one hand, if the large amount of waste tires generated cannot be effectively recycled, it will cause great damage to the environment. Currently, the main methods for treating waste tires include landfill, virgin tire recycling, thermal recycling, and recycling. Among these, pyrolysis can not only thoroughly and effectively process and recycle waste tires but also produce high-value-added products, such as pyrolysis gas, pyrolysis oil, and pyrolysis carbon black, making it one of the most promising tire recycling methods. On the other hand, the price of carbon black, one of the raw materials for tires, is also rising continuously, becoming one of the factors restricting tire production. Based on this, pyrolysis carbon black, as a relatively high-quality carbon black substitute, is currently a major focus for tire companies. Using pyrolysis carbon black instead of virgin carbon black in existing formulations can significantly reduce formulation costs while obtaining tire products with essentially the same performance or only slightly reduced performance.

[0003] As mentioned above, if the pyrolytic carbon black, the main solid product generated from the pyrolysis of waste tires, is reused in rubber production, a cycle of tire production-utilization-recycling-reproduction will be achieved, completing the product cycle and greatly promoting the sustainable development of the automotive and road transportation industries.

[0004] However, since pyrolysis carbon black is obtained from tire recycling, it has already undergone cross-linking in the original product, resulting in the loss of most of its surface active sites and a significant decrease in activity. Furthermore, its high ash content, meaning a large number of impurities occupy the surface of the carbon black aggregates, also affects its cross-linking ability to some extent. Therefore, to improve the performance of pyrolysis carbon black, surface modification and morphological alteration are necessary.

[0005] Therefore, how to effectively modify pyrolytic carbon black to improve the performance of rubber materials prepared from it is an important problem that needs to be solved in this field. Summary of the Invention

[0006] The main objective of this invention is to provide a pyrolytic carbon black fiber, its preparation method, and its application, in order to solve the problem that the pyrolytic carbon black used in the prior art has poor modification effect, resulting in low mechanical properties of rubber materials prepared from it.

[0007] To achieve the above objectives, the present invention provides a pyrolytic carbon black fiber comprising a polyvinylpyrrolidone fiber body and thermally pyrolytic carbon black with an N-acyl amino acid modified surface dispersed therein.

[0008] Further, the weight ratio of N-acyl amino acid to polyvinylpyrrolidone fiber body is 1 to 2:1; preferably, the weight ratio of thermally decomposed carbon black to polyvinylpyrrolidone fiber body is 0.285 to 0.8:1; more preferably, the weight ratio of thermally decomposed carbon black to N-acyl amino acid is 1:(1.25 to 1.75).

[0009] Furthermore, the diameter of the pyrolysis carbon black fiber is 20-50 nm; preferably, the mesh size of the pyrolysis carbon black is 80-100 mesh; preferably, the pyrolysis carbon black is waste tire pyrolysis carbon black.

[0010] Another aspect of the present invention provides a method for preparing the above-mentioned pyrolytic carbon black fiber, comprising: step S1, using N-acyl amino acids to modify the surface of pyrolytic carbon black to obtain modified pyrolytic carbon black; step S2, mixing and dispersing the modified pyrolytic carbon black, polyvinylpyrrolidone and spinning solvent to form a spinning solution, and then electrospinning the spinning solution to obtain pyrolytic carbon black fiber.

[0011] Furthermore, step S1 includes: step S1-1, sieving pyrolysis carbon black; step S1-2, preparing an N-acyl amino acid solution by mixing N-acyl amino acids and water at a weight ratio of 1:(4-6); step S1-3, mixing the N-acyl amino acid solution and pyrolysis carbon black in a ball mill jar, and obtaining a modified carbon black suspension after ball milling; step S1-4, centrifuging and drying the modified carbon black suspension to obtain modified pyrolysis carbon black.

[0012] Furthermore, step S2 includes: step S2-1, dispersing modified pyrolytic carbon black in a spinning solvent to obtain a suspension, dissolving polyvinylpyrrolidone in the suspension to obtain a spinning solution; step S2-2, electrospinning the spinning solution using an electrospinning machine, and drying it to obtain pyrolytic carbon black fibers; preferably, the spinning solvent is N,N-dimethylformamide.

[0013] Furthermore, the grinding jar is a polytetrafluoroethylene jar, and the abrasive balls used in the grinding process are stainless steel balls with a diameter of 1.8 to 2.2 mm; preferably, the grinding speed is 190 to 210 r / min during the grinding process.

[0014] Further, the solid content concentration in the suspension obtained in step S2-1 is 32.5-37.5 g / L, and the mass concentration of polyvinylpyrrolidone in the spinning solution is 6.25-17.5 g / L; preferably, stirring is carried out at room temperature for 6-12 h; preferably, during electrospinning, the spinning distance is 15-20 cm, the spinning voltage is 0.4-0.6 kV / cm, and the liquid pushing speed is 0.1-0.3 mm / min.

[0015] Another aspect of the present invention provides a rubber composite material comprising natural rubber and the above-mentioned pyrolyzed carbon black fibers.

[0016] Further, the rubber composite material comprises: 95-105 parts of natural rubber, 48-52 parts of pyrolyzed carbon black fiber, 4-6 parts of zinc oxide, 2-4 parts of stearic acid, 0.5-0.7 parts of DM accelerator, and 2-3 parts of sulfur; preferably, the length of the pyrolyzed carbon black fiber is 30-50 μm.

[0017] By applying the technical solution of this invention, the surface of pyrolytic carbon black is cleaned and modified using N-acyl amino acids, and the modified pyrolytic carbon black is dispersed through fibers to form a network structure, resulting in a larger contact area and better dispersibility. When this pyrolytic carbon black fiber is applied to rubber composites, it exhibits improved mechanical properties. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0019] As described in the background section, existing technologies suffer from poor modification effects of pyrolytic carbon black, resulting in rubber materials with low mechanical properties when prepared from it. To address this problem, this application provides a pyrolytic carbon black fiber comprising a polyvinylpyrrolidone fiber body and pyrolytic carbon black with an N-acyl amino acid-modified surface dispersed therein.

[0020] This invention utilizes N-acyl amino acids to clean and modify the surface of pyrolytic carbon black. As an anionic modifier, the unique structure of N-acyl amino acids combines surface activation and cleaning functions, imbuing the surface of the pyrolytic carbon black with a negative charge. This reduces the tendency for aggregation during dispersion, allowing the modified pyrolytic carbon black to disperse better within the polymer matrix. Simultaneously, polyvinylpyrrolidone fibers provide a network-like structural framework for the modified pyrolytic carbon black dispersed within it, thereby increasing the contact area and further enhancing the dispersibility of the modified pyrolytic carbon black. When this pyrolytic carbon black fiber is applied to rubber composites, it exhibits improved mechanical properties.

[0021] In a preferred embodiment, the weight ratio of N-acyl amino acid to polyvinylpyrrolidone fiber bulk is 1 to 2:1. Setting the weight ratio of N-acyl amino acid to polyvinylpyrrolidone fiber bulk within this range achieves a better modification effect while maintaining the low hydrophilicity of the polyvinylpyrrolidone fiber bulk to a greater extent, thereby improving the mixing uniformity and compatibility in the subsequent rubber material preparation process, resulting in a composite rubber material with better mechanical properties. Furthermore, to form a more complete, continuous, and stable three-dimensional network structure, thereby improving the dispersibility of pyrolytic carbon black, the weight ratio of pyrolytic carbon black to polyvinylpyrrolidone fiber bulk is preferably 0.285 to 0.8:1. More preferably, the weight ratio of pyrolytic carbon black to N-acyl amino acid is set to 1:(1.25 to 1.75), that is, the N-acyl amino acid modifier is slightly in excess, so as to achieve more complete surface modification, thereby obtaining pyrolytic carbon black with better modification effect, while also better protecting the integrity and uniformity of the surface morphology of the pyrolytic carbon black. Since the improvement efficiency of modifiers is not 100%, excessive modification is required to ensure that the modifier exists in the modifier environment, thereby fully increasing the surface contact area and time with the modifier.

[0022] In order to obtain pyrolysis carbon black fibers with more suitable size and morphology, so that the rubber composite material made from them as a component has better mechanical properties, the inventors, through a large number of experiments and creative work, found that in a typical embodiment, setting the diameter of the pyrolysis carbon black fibers to 30-50 nm can more effectively improve the hardness and tensile strength of the final rubber composite material.

[0023] In this field, the raw material for pyrolysis carbon black is generally coarse rubber particles obtained from tire crushing, containing some steel wire. The coarse rubber particles are fed into a high-temperature furnace for pyrolysis, yielding rubber residue and pyrolysis oil. The rubber residue is then magnetically separated, and the separated steel wire is collected to obtain coarse pyrolysis carbon black. The pyrolysis carbon black used in this invention is pyrolysis carbon black powder obtained by sieving coarse pyrolysis carbon black through a 120-mesh sieve. In a preferred embodiment, the pyrolysis carbon black is waste tire pyrolysis carbon black; preferably, the mesh size of the pyrolysis carbon black is 80-100 mesh. Sieving the pyrolysis carbon black to this mesh size can prevent agglomeration during the initial modification and dispersion process, thereby more effectively increasing and improving its surface activity.

[0024] Another aspect of the present invention provides a method for preparing the above-mentioned pyrolytic carbon black fiber, comprising: step S1, using N-acyl amino acids to modify the surface of pyrolytic carbon black to obtain modified pyrolytic carbon black; step S2, mixing and dispersing the modified pyrolytic carbon black, polyvinylpyrrolidone and spinning solvent to form a spinning solution, and then electrospinning the spinning solution to obtain pyrolytic carbon black fiber.

[0025] The pyrolytic carbon black fibers prepared by the method described above in this invention possess superior surface properties and physical characteristics. Furthermore, the preparation method provided by this invention utilizes readily available raw materials, has a simple and convenient process, and employs an environmentally friendly N-acyl amino acid modifier, which is biodegradable after depletion. This further enhances environmental friendliness. Simultaneously, the electrospinning method allows the modified pyrolytic carbon black to form a network structure, increasing the contact area and thus improving its dispersibility. Based on this, the resulting pyrolytic carbon black fibers exhibit excellent performance, and their addition to composite materials can improve various mechanical properties. The network structure provides a higher rubber bonding surface at the same microscale, significantly increasing van der Waals forces compared to the original structure without morphological changes.

[0026] In a typical embodiment, step S1 includes: Step S1-1, sieving the pyrolytic carbon black to obtain a better-dispersed powdered pyrolytic carbon black. Step S1-2, preparing an N-acyl amino acid solution by mixing N-acyl amino acids and water at a weight ratio of 1:(4-6). This concentration of N-acyl amino acid solution allows for better dispersion of the pyrolytic carbon black, reducing the possibility of agglomeration and thus obtaining a more uniform dispersion system, providing favorable prerequisites for improving the subsequent modification effect. Step S1-3, mixing the N-acyl amino acid solution and the pyrolytic carbon black in a ball mill jar, and ball milling to obtain a modified carbon black suspension. Ball milling is used for the N-acyl amino acid-modified pyrolytic carbon black system in this invention, which can better improve the surface energy and surface polarity of the pyrolytic carbon black, thereby more effectively improving its dispersibility. Step S1-4, centrifuging and drying the modified carbon black suspension to obtain modified pyrolytic carbon black.

[0027] In a preferred embodiment, the ball milling method used in this invention is microwave ball milling, and the corresponding experimental instrument is a microwave planetary ball mill. Compared with other mixed modification methods, microwave ball milling can make the modifier more evenly distributed in the ball milling system and have a larger contact area with the pyrolysis carbon black to be modified, thereby obtaining a better modification effect. Furthermore, the microwave planetary ball mill used in this invention has external dimensions of 305mm × 508mm × 420mm, a rated voltage and rated frequency of 220V and 50Hz respectively, a rated input power of 1400W, a microwave output power of 900W (maximum), and a rated microwave frequency of 2450MHz. Because the electromagnetic field inside the microwave oven cavity changes at a rate as high as 2.45 billion times / s, the resulting microwave oven thermal effect can act on polar molecules such as water molecules in the ball milling system, causing them to oscillate back and forth. The high-speed friction between water molecules generates high heat, achieving the heating purpose. This significantly improves the ball milling modification effect in this invention, resulting in modified pyrolysis carbon black with a better dispersible surface, which is beneficial for the obtained nanofiber materials to exhibit better surface morphology and mechanical properties, ultimately leading to better overall performance of the obtained rubber composite material. Through extensive experiments, the inventors discovered that using the above parameters to set the microwave planetary ball mill used in the ball milling modification process can more effectively improve the various mechanical properties of the final obtained rubber composite material.

[0028] Specifically, during the experiment, the ball mill jar containing pyrolysis carbon black and modifier solution was installed into the puller sleeve of the ball mill. After symmetrical installation, the V-bolts were tightened first using two force-applying sleeves, and then the lock nuts were tightened to prevent the jar from loosening during ball milling. After the ball mill jar was installed, the protective cover was put on, and the safety switch was turned on to start operation.

[0029] Furthermore, to achieve better dispersion, a polytetrafluoroethylene (PTFE) milling jar was selected, with a diameter of 140 mm, a height of 90 mm, and a volume of 1.38 L. The abrasive balls used during the milling process were stainless steel balls with a diameter of 1.8–2.2 mm, to ensure more thorough contact and collision between the pyrolytic carbon black and the solute components in the N-acyl amino acid solution, thereby enhancing the modification effect. Additionally, to improve the modification effect while better protecting the surface morphology and properties, the preferred milling speed during the milling process was 190–210 r / min.

[0030] The ball milling process also includes adding grinding media to the ball milling jar. The total volume of the grinding media is greater than 1 / 3 of the volume of the ball milling jar, while the total volume of the grinding media, N-acyl amino acid solution, and thermally decomposed carbon black is less than 3 / 4 of the volume of the ball milling jar. This allows the grinding media and the material being ball-milled to move and collide more fully, enhancing the modification effect, while also improving ball milling efficiency, shortening the experimental cycle, and increasing production capacity.

[0031] In order to enable the solid components, namely the modified pyrolytic carbon black, in the ball-milled suspension to be dispersed more efficiently, thereby shortening the experimental cycle and improving efficiency, the centrifugation speed used in the centrifugation process is preferably 4800-5200 rpm and the time is 12-18 min.

[0032] Based on the above, step S2 further includes: step S2-1, dispersing modified pyrolytic carbon black in a spinning solvent to obtain a suspension, dissolving polyvinylpyrrolidone in the suspension to obtain a spinning solution; step S2-2, electrospinning the spinning solution using an electrospinning machine, and drying it to obtain pyrolytic carbon black fibers; preferably, the spinning solvent is N,N-dimethylformamide, which, compared with other solvents commonly used in the art, has better polarity and is better suited to the experimental system in this invention. At the same time, the inventors have found through a large number of experiments that using DMF as a spinning solvent can enable the modified pyrolytic carbon black component in the final rubber material to obtain better dispersibility than other organic solvents. The reason for this is that the unique aldehyde group and dimethylamine group in its structure can promote the formation of the network structure of the modified pyrolytic carbon black in this invention. Polyvinylpyrrolidone is preferably of the K90 molecular weight type because it can form a homogeneous system with modified pyrolytic carbon black, and the nanofibers obtained by electrospinning can still have a complete and continuous morphological structure. At the same time, compared with other polymers, polyvinylpyrrolidone exhibits a more suitable surface tension for the spinning solution containing modified pyrolytic carbon black involved in this invention, thereby obtaining a nanofiber structure with better overall performance.

[0033] To achieve degassing, the spinning solution needs to be allowed to stand before electrospinning begins. After considering both the spinning effect and the experimental cycle, the inventors optimally selected a standing time of 10–14 hours to more effectively reduce time consumption and costs. After standing, the final pre-spinning solution is placed in a dry, light-protected environment and stirred until ready for use, with the stirring speed not exceeding 300 rpm.

[0034] Furthermore, to improve the electrospinning effect and obtain a more complete and stable structure, the solid content concentration in the suspension obtained in step S2-1 is 32.5–37.5 g / L, and the mass concentration of polyvinylpyrrolidone in the spinning solution is 6.25–17.5 g / L. To enable polyvinylpyrrolidone to dissolve more quickly in the suspension containing modified pyrolytic carbon black, stirring is preferably carried out at room temperature, specifically 25°C, for 6–12 h. Preferably, to obtain pyrolytic carbon black fibers with a more uniform morphology, the spinning distance is 15–20 cm, the spinning voltage is 0.4–0.6 kV / cm, and the liquid pushing speed is 0.1–0.3 mm / min during electrospinning.

[0035] In a typical embodiment, the drying process of pyrolytic carbon black fibers uses a drying temperature of 100–110°C and a drying time of 12–24 hours. This temperature and time range is designed to better remove the solvent used in the spinning process, namely N,N-dimethylformamide. This lower temperature range can also more effectively protect the N-acyl amino acids on the modified pyrolytic carbon black from detaching from their surface and prevent carbonization of the carbon black particles. At the same time, it can retain polyvinylpyrrolidone, thereby obtaining a structurally complete fiber material and maintaining the network structure formed by the modified carbon black.

[0036] In the experiment, specifically, a roller receiver was used as the negative electrode for electrospinning, covered with an aluminum foil as the receiving electrode. After the 30mL syringe containing the pre-spinning solution was fully injected, the aluminum foil covered with nanofibers was removed from the roller receiver, dried, and the resulting pyrolyzed carbon black fibers were peeled off the aluminum foil surface and collected in a clean crucible for later use.

[0037] Another aspect of the present invention provides a rubber composite material comprising natural rubber and the aforementioned pyrolysis carbon black fibers. The resulting rubber composite material, relying on the network structure of the aforementioned pyrolysis carbon black fibers and the good dispersibility of the carbon black dispersed therein, possesses more uniform properties and superior mechanical performance, thus enabling its application in various fields, including tires.

[0038] Furthermore, to obtain a rubber composite material with superior overall performance, the rubber composite material provided by this invention comprises: 95-105 parts of natural rubber, 48-52 parts of pyrolyzed carbon black fiber, 4-6 parts of zinc oxide, 2-4 parts of stearic acid, 0.5-0.7 parts of DM accelerator, and 2-3 parts of sulfur. Moreover, to maximize the performance-enhancing effect of pyrolyzed carbon black fiber in the rubber composite material, thereby obtaining a product with superior mechanical properties, the length of the pyrolyzed carbon black fiber is preferably 30-50 μm.

[0039] The preparation process of rubber composite materials includes compounding and vulcanization. The compounding step includes cleaning the two rolls and operating table of the open mill, washing the rolls of the open mill with a small amount of natural rubber until there is no more dust on the rolls, and then mixing in the open mill. The roller temperature is controlled at (70±5)℃. The roller gap of the open mill is adjusted to 0.8mm, and the raw rubber is broken once without wrapping the roller. The roller gap of the open mill is adjusted to 1.4mm, and natural rubber is added and wrapped around the front roller. The cutter is used twice. The roller gap is adjusted to 1.65mm, stearic acid is added, and the cutter is used once. Sulfur, accelerator and zinc oxide are added, and the cutter is used twice. All the pyrolyzed carbon black fibers are added. After there is no obvious powder on the surface of the rubber compound, the cutter is used twice. The roller gap is then adjusted to 1.9mm, and all the pyrolyzed carbon black fibers scattered in the receiving tray are mixed in. The cutter is used three times. The roller gap is adjusted to 0.8mm, and the rolled rubber compound is passed vertically through the roller gap six times without wrapping the roller. The roller gap is adjusted so that the thickness of the rubber sheet is not less than 6mm. The folded rubber sheet is passed through the roller gap four times. The roller gap is adjusted so that the thickness of the rubber sheet is about 2.2mm before the sheet is unloaded. Before vulcanization, the rubber sheet is left at (23±3)℃ for 24h before vulcanization treatment. The vulcanization step is carried out on a flat vulcanizing apparatus: the temperature is controlled at 150°C and the time is 30 minutes. After vulcanization, the rubber sheet forms a uniform sheet with a thickness of about 2 mm in the mold, which is the rubber composite material sample of the present invention.

[0040] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0041] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0042] Example 1

[0043] Preparation of a rubber composite material:

[0044] Step S1, Sample processing: Pass the waste tire pyrolysis carbon black through a 120-mesh sieve to obtain the raw material pyrolysis carbon black powder with a mesh size of 80-100 mesh; Dissolve N-acyl amino acids (analytical grade) in deionized water and prepare an N-acyl amino acid (analytical grade) solution for later use at a mass ratio of solute to solvent of 1:5.

[0045] Step S2, Modification: Take 200g of pyrolytic carbon black and weigh out an N-acyl amino acid (analytical grade) solution at a ratio of N-acyl amino acid:pyrolytic carbon black = 1.25 (weight ratio), and transfer it to a ball mill jar. Add grinding media to the ball mill jar, with the total volume of the grinding media being 1 / 4 of the total volume, and the total volume of the grinding media and the material being 1 / 2 of the total volume. Ball mill at a speed of 200 r / min for 60 min. After that, remove the ball-milled modified carbon black mixture suspension and centrifuge it at 5000 rpm for 15 minutes to separate the modified pyrolytic carbon black. Dry it in an oven at 105℃ for 2 hours and store it in a desiccator.

[0046] Step S3, electrospinning: Weigh 60g of modified pyrolytic carbon black and add it to 300mL of N,N-dimethylformamide solvent. After it dissolves and forms a stable and uniform suspension, add 20g of polyvinylpyrrolidone (PVP) while stirring at 25℃. After standing for 12h, place the suspension in a dry, light-protected environment and stir at 300 rpm. Place the prepared sol into a 30mL syringe and perform electrospinning using an electrospinning machine. The injection speed is set to 0.2mm / min, and the electrostatic field at both ends is set to 0.5kV / cm. A roller receiver is used as the negative electrode, covered with an aluminum foil as the receiving electrode. After the syringe is completely injected, remove the aluminum foil covered with nanofibers from the roller receiver, dry it in an oven at ℃ for h, and then peel the nanofibers off the aluminum foil surface and collect them in a clean crucible, thus obtaining pyrolytic carbon black fibers.

[0047] Step S4, Preparation: After cleaning the two rolls and operating table of the open mill, use a small amount of natural rubber to wash the rolls until there is no more dust on the rolls. Mixing is then carried out in the open mill. The roll temperature is controlled at (70±5)℃. The roll gap of the open mill is adjusted to 0.8mm. The raw rubber is broken once without wrapping the rolls. The roll gap is adjusted to 1.4mm. Natural rubber is added and wrapped around the front rolls. The rolls are cut twice. The roll gap is adjusted to 1.65mm. Stearic acid is added. The rolls are cut once. Sulfur, accelerator, and zinc oxide are added. The rolls are cut twice. All the pyrolyzed carbon black fibers are added. After the rubber compound surface is free of obvious powder, the rolls are cut twice. The roll gap is then adjusted to 1.9mm. All the pyrolyzed carbon black fibers scattered in the receiving tray are mixed in. The mixture is then cut... The rubber sheet is cut 3 times, and the roller gap is adjusted to 0.8mm. The rolled rubber sheet is then passed vertically through the roller gap 6 times without wrapping the roller. The roller gap is adjusted so that the thickness of the rubber sheet is not less than 6mm. The folded rubber sheet is then passed through the roller gap 4 times. The roller gap is adjusted so that the thickness of the rubber sheet is about 2.2mm before it is unloaded. Before vulcanization, the rubber sheet is left to stand at (23±3)℃ for 24 hours before vulcanization treatment. The composition is as follows: natural rubber 100g, pyrolyzed carbon black fiber 50g, zinc oxide 5g, stearic acid 3g, DM accelerator 0.6g, and sulfur 2.5g.

[0048] Step S5, vulcanization: Vulcanization is carried out on a flat vulcanizing machine, with the temperature controlled at 150℃ and the time at 30min. After vulcanization, the film forms a uniform thin sheet sample with a thickness of about 2mm in the mold.

[0049] Example 2

[0050] Preparation of a rubber composite material:

[0051] The difference between this example and Example 1 is that the ratio of N-acyl amino acid to pyrolytic carbon black is 1.50 (by weight).

[0052] Example 3

[0053] Preparation of a rubber composite material:

[0054] The difference between this example and Example 1 is that the ratio of N-acyl amino acid to pyrolytic carbon black is 1.75 (by weight).

[0055] Example 4

[0056] Preparation of a rubber composite material:

[0057] The difference between this embodiment and Example 1 is that the ratio of N-acyl amino acid to pyrolytic carbon black is 1.00 (by weight).

[0058] Example 5

[0059] Preparation of a rubber composite material:

[0060] The difference between this embodiment and Example 1 is that the ratio of N-acyl amino acid to pyrolytic carbon black is 2.00 (by weight).

[0061] Example 6

[0062] Preparation of a rubber composite material:

[0063] The difference between this embodiment and embodiment 1 is that in the modification process of step S2, microwave ball milling was not used, but ordinary ball milling was used, while the ball milling speed and time were the same as in embodiment 1.

[0064] Example 7

[0065] Preparation of a rubber composite material:

[0066] The difference between this embodiment and Embodiment 1 is that in the electrospinning process of step S3, DMF was not used as a solvent, but deionized water was used instead.

[0067] Example 8

[0068] Preparation of a rubber composite material:

[0069] The difference between this embodiment and Embodiment 1 is that in the electrospinning process of step S3, DMF was not used as a solvent, but DMSO was used instead.

[0070] Example 9

[0071] Preparation of a rubber composite material:

[0072] The difference between this embodiment and Embodiment 1 is that PVP was not used in the electrospinning process of step S3; instead, polyacrylic acid was used.

[0073] Example 10

[0074] Preparation of a rubber composite material:

[0075] The difference between this embodiment and Embodiment 1 is that PVP was not used in the electrospinning process of step S3, but PET was used instead.

[0076] Comparative Example 1

[0077] Preparation of a rubber composite material:

[0078] The difference between this comparative example and Example 1 is that the modification treatment in step S2 was not performed, i.e., no N-acyl amino acid was added.

[0079] Comparative Example 2

[0080] Preparation of a rubber composite material:

[0081] The difference between this comparative example and Example 1 is that the electrospinning treatment in step S3 was not performed, that is, the nanofiber structure was not formed, and the modified pyrolytic carbon black was directly used for the subsequent preparation of rubber composite materials.

[0082] Comparative Example 3

[0083] Preparation of a rubber composite material:

[0084] The difference between this comparative example and Example 1 is that the N-acyl amino acid is replaced with another anionic modifier, specifically sodium dodecylbenzenesulfonate.

[0085] Comparative Example 4

[0086] Preparation of a rubber composite material:

[0087] The difference between this comparative example and Example 1 is that the N-acyl amino acid is replaced with another anionic modifier, specifically lauryl phosphate.

[0088] Performance testing:

[0089] MH: Same as GB / T 16584 "Determination of vulcanization properties of rubber using a rotorless vulcanizing apparatus"

[0090] Hardness: Same as GB / T531.1 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test.

[0091] Tensile strength: Same as GB / T 528 Determination of tensile properties of vulcanized rubber and thermoplastic rubber.

[0092] 300% constant elongation stress: Same as GB / T 528 "Determination of tensile properties of vulcanized rubber and thermoplastic rubber"

[0093] The performance test results of the various embodiments and comparative examples are shown in Table 1.

[0094] Table 1

[0095]

[0096]

[0097] As can be seen from the above description, the embodiments of the present invention clean and modify the surface of pyrolytic carbon black by N-acyl amino acids, and use fiber dispersion to form a network structure of the modified pyrolytic carbon black. The resulting pyrolytic carbon black fibers exhibit better mechanical properties when applied to rubber composites.

[0098] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0099] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pyrolysis carbon black fiber, characterized in that, The pyrolytic carbon black fiber comprises a polyvinylpyrrolidone fiber body and thermally pyrolytic carbon black with N-acyl amino acid-modified surface dispersed therein; the weight ratio of the thermally pyrolytic carbon black to the N-acyl amino acid is 1:(1.25~1.75); the N-acyl amino acid is an anionic modifier; The method for preparing the pyrolysis carbon black fiber includes: Step S1, Preparation of modified pyrolysis carbon black: Step S1-1: Screening of pyrolysis carbon black; Step S1-2: Prepare an N-acyl amino acid solution by mixing N-acyl amino acids and water in a weight ratio of 1:(4~6); Steps S1-3: The N-acyl amino acid solution and the pyrolysis carbon black are mixed in a ball mill jar and ball milled to obtain a modified carbon black suspension; Steps S1-4: Centrifuge and dry the modified carbon black suspension to obtain the modified pyrolysis carbon black; Step S2: The modified pyrolytic carbon black, polyvinylpyrrolidone, and spinning solvent are mixed and dispersed to form a spinning solution, and then the spinning solution is electrospun to obtain the pyrolytic carbon black fiber.

2. The pyrolysis carbon black fiber according to claim 1, characterized in that, The weight ratio of the N-acyl amino acid to the polyvinylpyrrolidone fiber body is 1~2:

1.

3. The pyrolysis carbon black fiber according to claim 2, characterized in that, The weight ratio of the pyrolytic carbon black to the polyvinylpyrrolidone fiber body is 0.285~0.8:

1.

4. The pyrolysis carbon black fiber according to any one of claims 1 to 3, characterized in that, The diameter of the pyrolysis carbon black fiber is 20~50nm.

5. The pyrolysis carbon black fiber according to claim 4, characterized in that, The pyrolysis carbon black has a mesh size of 80-100 mesh.

6. The pyrolysis carbon black fiber according to claim 4, characterized in that, The pyrolysis carbon black is pyrolysis carbon black from waste tires.

7. A method for preparing pyrolysis carbon black fiber according to any one of claims 1 to 6, characterized in that, The preparation method includes: Step S1: The N-acyl amino acid is used to modify the surface of the pyrolysis carbon black to obtain modified pyrolysis carbon black. Step S1-1: Screening of pyrolysis carbon black; Step S1-2: Prepare an N-acyl amino acid solution by mixing N-acyl amino acids and water in a weight ratio of 1:(4~6); Steps S1-3: The N-acyl amino acid solution and the pyrolysis carbon black are mixed in a ball mill jar and ball milled to obtain a modified carbon black suspension; Steps S1-4: Centrifuge and dry the modified carbon black suspension to obtain the modified pyrolysis carbon black; Step S2: The modified pyrolytic carbon black, polyvinylpyrrolidone, and spinning solvent are mixed and dispersed to form a spinning solution, and then the spinning solution is electrospun to obtain the pyrolytic carbon black fiber.

8. The method for preparing pyrolysis carbon black fiber material according to claim 7, characterized in that, Step S2 includes: Step S2-1: Disperse the modified pyrolytic carbon black in the spinning solvent to obtain a suspension, and dissolve the polyvinylpyrrolidone in the suspension to obtain the spinning solution; Step S2-2: Electrospinning the spinning solution using an electrospinning machine, and then drying it to obtain the pyrolyzed carbon black fiber.

9. The method for preparing pyrolysis carbon black fiber material according to claim 8, characterized in that, The spinning solvent is N,N-dimethylformamide.

10. The method for preparing pyrolysis carbon black fiber material according to claim 7, characterized in that, The grinding jar is a polytetrafluoroethylene jar, and the abrasive balls used in the grinding process are stainless steel balls with a diameter of 1.8~2.2mm.

11. The method for preparing pyrolysis carbon black fiber material according to claim 10, characterized in that, During the ball milling process, the ball milling speed is 190~210 r / min.

12. The method for preparing pyrolysis carbon black fiber material according to claim 8, characterized in that, The solid content concentration in the suspension is 32.5~37.5 g / L, and the mass concentration of polyvinylpyrrolidone in the spinning solution is 6.25~17.5 g / L.

13. The method for preparing pyrolysis carbon black fiber material according to claim 12, characterized in that, The dissolution is carried out by stirring at room temperature for 6 to 12 hours.

14. The method for preparing pyrolysis carbon black fiber material according to claim 12, characterized in that, During the electrospinning process, the spinning distance is 15~20cm, the spinning voltage is 0.4~0.6 kV / cm, and the liquid pushing speed is 0.1~0.3 mm / min.

15. A rubber composite material, characterized in that, The rubber composite material includes natural rubber and pyrolyzed carbon black fiber as described in any one of claims 1 to 6.

16. The rubber composite material according to claim 15, characterized in that, By weight, the rubber composite material comprises: 95-105 parts of natural rubber, 48-52 parts of pyrolyzed carbon black fiber, 4-6 parts of zinc oxide, 2-4 parts of stearic acid, 0.5-0.7 parts of DM accelerator, and 2-3 parts of sulfur.

17. The rubber composite material according to claim 16, characterized in that, The length of the pyrolysis carbon black fiber is 30~50μm by weight.

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