Functional plastic fiber master batch material and preparation method thereof

Abstract

The invention discloses a functional plastic fiber master batch material and a preparation method thereof, and relates to the technical field of plastic master batches. The functional plastic fiber master batch material is prepared from layered nano silicate loaded nitrogen-doped carbon nanofibers, a multi-level composite functional material, polypropylene, an antioxidant and calcium stearate, the layered nano silicate loaded nitrogen-doped carbon nanofibers and the multi-level composite functional material are combined for use, so that the interfacial compatibility and binding property with a polypropylene matrix are enhanced, the mechanical property, flame retardance and conductivity of the plastic can be synergistically enhanced through a formed interpenetrating network structure, and the application range is widened.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic masterbatches, and in particular relates to a functional plastic fiber masterbatch material and a preparation method thereof. Background Art

[0002] Traditional petroleum-based plastics refer to plastic materials that are made from petroleum as raw materials through various synthetic processes. This type of plastic is widely used around the world due to its excellent physical and chemical properties, low production costs and wide applicability. The most common petroleum-based plastics are mainly the following categories: polyethylene, polypropylene, polyvinyl chloride, polystyrene, etc.; petroleum-based plastics usually have good chemical stability and corrosion resistance, can adapt to the requirements of long-term use in various environments, and also have high strength and toughness, which can meet the needs of a variety of industrial and daily applications. At the same time, petroleum-based plastics have excellent processing performance and can be molded through various methods such as injection molding, extrusion, blow molding, etc. to produce products of various shapes and uses, which have reflected a wide range of application needs in industrial fields such as automobiles, electrical, electronics, packaging, and construction.

[0003] The existing technology currently has the following problems: Materials such as polypropylene have weak flame retardancy and mechanical properties, which imposes many restrictions on their application. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention proposes a functional plastic fiber masterbatch material, comprising the following components in parts by weight: 5-10 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 10-20 parts of multi-level composite functional materials, 70-90 parts of polypropylene, 1-3 parts of antioxidants, and 3-5 parts of calcium stearate.

[0005] The layered nano-silicate loaded nitrogen-doped carbon nanofiber is prepared from the following components in parts by weight: 1-2 parts of modified layered nano-silicate, 6-10 parts of polyacrylonitrile, 1-5 parts of polymethyl methacrylate, 1-2 parts of urea, and 1-2 parts of melamine.

[0006] The method for preparing the layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water, ultrasonicate for 30-50 min, and obtain a suspension for standby use. Then, dissolve 0.04-0.1 g of hexadecyltrimethylammonium bromide in 20 mL of 40-50 ° C water, stir until completely dissolved, and then add the hexadecyltrimethylammonium bromide solution dropwise to the suspension within 20-30 min while stirring. Stir at 60-70 ° C for 24 h, centrifuge at a centrifugal speed of 12000-16000 rpm and a centrifugal time of 10-15 min. The precipitate is washed alternately with deionized water and ethanol solution for 3 times, dried, and ground. Hexadecyltrimethylammonium bromide is inserted into the silicate interlayer through cation exchange, which expands the interlayer spacing and is more conducive to the embedding of polymer molecular chains. At the same time, the long alkyl chain of hexadecyltrimethylammonium bromide covers the silicate surface, changing it from hydrophilic to hydrophobic, improving its compatibility with the plastic matrix, and is conducive to exerting strengthening, toughening and flame retardant effects, thereby obtaining modified layered nanosilicate. (2) Dispersing the modified layered nanosilicate described in step (1) in a mixed solvent of 10 mL of N, N-dimethylformamide and acetone, wherein the volume ratio of N, N-dimethylformamide to acetone is 7:3, stirring continuously for 1-2 hours, then adding 0.1-0.2 g of urea and 0.1-0.2 g of melamine, stirring for 10-20 minutes, then adding polymethyl methacrylate, and finally adding 0.6-1.0 g of polyacrylonitrile, stirring at 40-45°C for 8-12 hours. In this process, the modified layered nanosilicate is dispersed in the polymer matrix to form a nano-brick-gravel structure, polyacrylonitrile provides a rigid skeleton, polymethyl methacrylate fills the pores, and the molecules of urea and melamine are evenly distributed between the polymer chains, which is conducive to the subsequent heat treatment to generate porous or flame retardant active sites. A nano-composite system with excellent dispersion stability, flame retardancy and spinning fluidity is prepared, and a spinning precursor solution is obtained; (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and then transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by a syringe pump. The flow rate was set to 0.8-1.0 mL / h, the voltage was 12-18 kV, and the distance was 12-15 cm. The collected spun fibers were placed in a muffle furnace, first heated to 130-150 ° C at a rate of 2 ° C / min and kept warm for 30 minutes, and then oxidized in an air atmosphere at 240-250 ° C for 70-80 minutes. The stabilized fibers were then placed in a tubular furnace and heated to 700-800 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 10-20% of the total gas flow. The fibers were carbonized for 70-90 minutes and cooled. A fiber structure with porous flame retardant sites on the surface was obtained by electrospinning and high-temperature carbonization. After pre-oxidation and carbonization, polyacrylonitrile formed a carbon fiber skeleton and The nitrogen-doped active sites are retained, and the modified layered nanosilicates are embedded in the fiber in the form of exfoliated nanosheets, which improves the stability of the structure after carbonization and prevents pore collapse. During the carbonization stage, the nitrogen-doped carbon network structure is formed under the action of ammonia penetration and residual polyacrylonitrile molecules, forming a three-dimensional network in the plastic matrix, which not only inhibits the slippage of the plastic molecular chain, but also improves the tensile strength and impact resistance of the material through stress transfer. At the same time, the carbon fiber forms a carbon layer during combustion, isolating oxygen and heat, and delaying combustion. The nitrogen-doped sites promote the catalytic carbonization of the polymer, forming a dense carbon layer, and enhancing the flame retardant properties. The physical barrier of the modified layered nanosilicate is also conducive to blocking gas diffusion and heat conduction, and the modified layered nanosilicate promotes fiber dispersion, avoids agglomeration, and optimizes the conductive path. The carbon fiber provides a conductive network, and nitrogen doping provides additional free electrons, reduces resistivity, and improves conductive properties, thereby obtaining layered nanosilicate-loaded nitrogen-doped carbon nanofibers. Preferably, in step (1), the amount of layered nanosilicate added is 0.5-1.0 g. When layered nanosilicate is used as a nanofiller for plastics, it can not only improve the flame retardancy of the plastics through physical barrier and catalytic carbonization mechanism, but also improve the mechanical properties of the plastics such as tensile strength and impact toughness. Preferably, in step (2), the amount of polymethyl methacrylate added is 0.1-0.5 g. Polymethyl methacrylate can reduce the viscosity of the spinning solution and improve the spinnability. At the same time, as a pore-forming auxiliary agent, it can further optimize and adjust the porous structure of the fiber.

[0007] The present invention also provides a method for preparing a functional plastic fiber masterbatch material, which specifically comprises the following steps: S1. Disperse 4.0-5.0 g of ammonium polyphosphate in 50 mL of anhydrous methanol and ultrasonically treat for 0.5-1 h to form a dispersion I for standby use. Mix 600.0-650.0 mg of γ-cyclodextrin and 200.0-300.0 mg of potassium hydroxide in 30 mL of a 30% methanol solution as solution II for standby use. Dissolve Pluronic F127 and carboxylated carbon nanotubes in 30 mL of anhydrous methanol and ultrasonicate for 20-30 min to form solution III for standby use. Then, solution II and solution III are added dropwise to dispersion I in sequence, stirred at 25 ° C for 2-3 h, centrifuged, and the particles are collected. They are washed with anhydrous ethanol and anhydrous methanol for 3-5 times respectively, and vacuum dried. With ammonium polyphosphate as the core, it provides expansion flame retardant function, γ- Cyclodextrin coats ammonium polyphosphate through hydrogen bonding or physical adsorption. One end of the amphiphilic block of PluronicF127 is combined with γ-cyclodextrin and the other end is connected to carboxylated carbon nanotubes to form a multi-layer stable coating, which improves the compatibility with the plastic matrix, avoids migration and precipitation during melt processing, and enhances the interface stability. Among them, the carboxylated carbon nanotubes not only provide a nano-enhancement effect, which is beneficial to the improvement of mechanical properties, but also promotes the formation of a dense carbon layer, and synergistically enhances the maze effect with γ-cyclodextrin, stabilizes the carbon layer structure, and reduces the expansion of carbon layer cracks. The hydrophobic cavity of γ-cyclodextrin also constructs a barrier zone with the hydrophilic outer wall to delay the escape of combustible gas. At the same time, the evenly dispersed carboxylated carbon nanotubes can construct a conductive network on the surface of the composite, reduce the resistivity, and obtain γ-cyclodextrin-modified composite particles. S2, the γ-cyclodextrin modified composite particles described in step S1 are dispersed in 100 mL of a 60% methanol solution by mass, ultrasonically treated for 30-40 min, and used as dispersion A. 80.0-90.0 mg of cobalt nitrate hexahydrate is dissolved in 80 mL of anhydrous methanol, and then zinc nitrate hexahydrate is added to be used as solution B. 0.2-0.3 g of 3,5-diamino-1,2,4-triazole is dissolved in 50 mL of anhydrous methanol to be used as solution C. Solution B and solution C are then added dropwise to dispersion A, heated to 40-50 ° C, stirred for 2-3 h, centrifuged, and the precipitate is washed with anhydrous methanol 3 times. Finally, it is placed in a 0.5-1.0% oleic acid methanol solution and soaked for 20-30 min, taken out, Supercritical drying uses γ-cyclodextrin-modified composite particles as the core layer, a Co / Zn bimetallic organic framework as the middle layer, and an outer shell coated with oleic acid molecules to improve compatibility with the plastic matrix and present a porous through-hole structure. The hierarchical channel effect allows the nanofiller to better play its role, restricting the movement of plastic molecular chains and absorbing impact energy through pore wall deformation, significantly enhancing mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposes into metal oxides at high temperatures, catalyzing the polymer to form a dense carbon layer, isolating heat and oxygen, and extending heat conduction and diffusion through tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic increases the lattice stress and dislocation density, promoting electron transition conduction, which is also beneficial to improving flame retardancy and electrical conductivity, resulting in a multi-level composite functional material. S3, the layered nano-silicate loaded nitrogen-doped carbon nanofibers are annealed at 130-150 ° C. The annealing pretreatment can eliminate surface adsorbed water, stabilize nitrogen-containing functional groups, and avoid subsequent high-temperature extrusion decomposition to produce gas, and then mixed with the multi-level composite functional material described in step S2, and then polypropylene, antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant is composed of equal weights of antioxidant 1010 and antioxidant 168. The mixed material is then added to the extruder for melt extrusion and granulation, and the feeding section temperature is controlled at 160-170 ° C, and the melt extrusion temperature is 180-200 ° C. The layered nano-silicate loaded nitrogen-doped carbon nanofibers can be entangled on the surface of the multi-level composite functional material during the melt extrusion process to form an interpenetrating network. The polar groups introduced by nitrogen doping can form hydrogen bonds or coordination effects with the metal nodes of the multi-level composite functional material, thereby enhancing the interface binding with the polypropylene matrix, which is beneficial to the improvement of the mechanical properties, flame retardancy and conductivity of the plastic by the filler, broadening the application of the plastic, and obtaining a functional plastic fiber masterbatch material; Preferably, in step S1, the amounts of Pluronic F127 and carboxylated carbon nanotubes added are 150.0-200.0 mg and 10.0-15.0 mg, respectively. The carboxylated carbon nanotubes have carboxyl groups on their surfaces, which can interact with the hydrophilic PEO segments of Pluronic F127 through hydrogen bonds to form a more stable dispersion system, while the hydrophobic PPO segments wrap the non-polar regions of the carbon nanotubes to form a "micelle-nanotube" composite structure, further inhibiting agglomeration. Preferably, in step S2, the amount of zinc nitrate hexahydrate added is 20.0-30.0 mg. The mild coordination effect of zinc ions reduces the brittleness caused by excessive cross-linking, and can also make the metal-organic framework material more flexible and not easy to break during injection molding and shearing. During combustion, the zinc ions are converted into nano-ZnO, filling the pores of the carbon layer to make it denser. In addition, the introduction of zinc ions narrows the band gap of the metal-organic framework material, and its tetrahedral coordination configuration promotes interfacial contact with carboxylated carbon nanotubes, optimizes the percolation network, and thus enhances the mechanical properties, flame retardancy and conductivity.

[0008] The beneficial effects achieved by the present invention are as follows: The present invention uses a combination of layered nano-silicate loaded nitrogen-doped carbon nanofibers and multi-level composite functional materials, which not only enhances the interface compatibility and bonding with the polypropylene matrix, but also synergistically enhances the mechanical properties, flame retardancy and electrical conductivity of the plastic through the formed interpenetrating network structure, thereby broadening the scope of application; in the layered nano-silicate loaded nitrogen-doped carbon nanofibers, polyacrylonitrile is pre-oxidized and carbonized to form a carbon fiber skeleton, and the modified layered nano-silicate is embedded in the fiber in the form of peeled nano-sheets, which improves the stability of the carbonized structure and prevents pore collapse. During the carbonization stage, ammonia penetration and the action of residual polyacrylonitrile molecules form a nitrogen-doped carbon network structure, thereby The filaments are filaments and high-temperature carbonized to finally obtain a carbon fiber structure with porous flame-retardant sites on the surface, which can form a three-dimensional network in the plastic matrix, not only inhibiting the slippage of the plastic molecular chain, but also improving the tensile strength and impact resistance of the material through stress transfer. At the same time, the carbon fiber forms a carbon layer when burning, isolating oxygen and heat, delaying combustion, and the nitrogen-doped sites promote the catalytic carbonization of the polymer to form a dense carbon layer, enhancing the flame retardant performance, and the carbon fiber provides a conductive network, and the nitrogen doping provides additional free electrons, reducing the resistivity and improving the conductive performance. Among them, the physical barrier of the modified layered nanosilicate is also conducive to blocking gas diffusion and heat conduction. The modified layered nanosilicate can also promote fiber dispersion, avoid agglomeration, and optimize the conductive path; the multilayer In the graded composite functional material, the composite particles modified with γ-cyclodextrin are used as the core layer, the Co / Zn bimetallic organic framework is used as the middle layer, and the oleic acid is used as the modified outer shell layer to form a porous through-hole composite structure. The hierarchical channel effect can better play the role of nanofiller, effectively restrict the movement of plastic molecular chains, and fully absorb impact energy by porous wall deformation, which significantly enhances the mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposes into metal oxides at high temperature, catalyzing the formation of a dense carbon layer to isolate heat and oxygen, and prolong the conduction and diffusion of heat through tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic leads to an increase in lattice stress and dislocation density, which promotes electron transition conduction and is also beneficial to the improvement of flame retardancy and electrical conductivity. Among them, γ-cyclodextrin coats ammonium polyphosphate through hydrogen bonding or physical adsorption, one end of the amphiphilic block of PluronicF127 is combined with γ-cyclodextrin, and the other end is connected to carboxylated carbon nanotubes, which enhances the maze effect, is beneficial to stabilizing the carbon layer structure, and reduces the expansion of carbon layer cracks. The hydrophobic cavity and hydrophilic outer wall of γ-cyclodextrin construct a barrier area, delaying the escape of combustible gas. At the same time, the uniformly dispersed carboxylated carbon nanotubes can construct a conductive network on the surface of the composite, reducing the resistivity. The present invention uses layered nanosilicate loaded nitrogen-doped carbon nanofibers, multi-level composite functional materials, polypropylene, antioxidants and calcium stearate to prepare a functional plastic fiber masterbatch material, which enhances mechanical properties, flame retardant properties and conductive properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1This is a scanning electron microscope image of the multi-layer composite functional material prepared in Example 1 of the present invention; Figure 2 The figures are the mechanical properties results of Examples 1-4 and Comparative Examples 1-3 of the present invention; Figure 3 The limiting oxygen index results of Examples 1-4 and Comparative Examples 1-3 of the present invention are shown in FIG. Figure 4 The volume resistivity results of Examples 1-4 and Comparative Examples 1-3 of the present invention are shown in FIG. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0012] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0013] Example 1 This embodiment proposes a functional plastic fiber masterbatch material, comprising the following components in parts by weight: 10 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 20 parts of multi-level composite functional materials, 90 parts of polypropylene, 3 parts of antioxidants, and 5 parts of calcium stearate.

[0014] The layered nano-silicate loaded nitrogen-doped carbon nanofiber is prepared from the following components in parts by weight: 2 parts of modified layered nano-silicate, 10 parts of polyacrylonitrile, 5 parts of polymethyl methacrylate, 2 parts of urea, and 2 parts of melamine.

[0015] The preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water. The amount of layered nanosilicate added is 1.0 g. When layered nanosilicate is used as a nanofiller for plastics, it can not only improve the flame retardancy of plastics through physical barrier and catalytic carbonization mechanism, but also improve the mechanical properties of plastics such as tensile strength and impact toughness. Ultrasonic treatment is performed for 50 minutes to obtain a suspension for standby use. Then, 0.1 g of hexadecyltrimethylammonium bromide is dissolved in 20 mL of 50°C water and stirred until completely dissolved. Then, the hexadecyltrimethylammonium bromide solution is added dropwise to the suspension within 30 minutes while stirring. The suspension was stirred at 70°C for 24 hours and centrifuged at a speed of 16,000 rpm for 15 minutes. The precipitate was washed alternately with deionized water and ethanol solution three times, dried, and ground. Cetyltrimethylammonium bromide was inserted into the silicate interlayer through cation exchange, thereby expanding the interlayer spacing and facilitating the embedding of polymer molecular chains. At the same time, the long alkyl chains of cetyltrimethylammonium bromide covered the silicate surface, changing its hydrophilicity to hydrophobicity, improving its compatibility with the plastic matrix, and facilitating the strengthening, toughening, and flame retardant effects, thereby obtaining a modified layered nanosilicate. (2) The modified layered nanosilicate described in step (1) was dispersed in a mixed solvent of 10 mL of N, N-dimethylformamide and acetone, wherein the volume ratio of N, N-dimethylformamide to acetone was 7:3, and the mixture was stirred for 2 h. Then, 0.2 g of urea and 0.2 g of melamine were added, and the mixture was stirred for 20 min. Then, polymethyl methacrylate was added in an amount of 0.5 g. Polymethyl methacrylate can reduce the viscosity of the spinning solution and improve the spinnability. At the same time, as a pore-forming auxiliary agent, the mixture was further optimized. The porous structure of the fiber was adjusted, and finally 1.0g of polyacrylonitrile was added and stirred at 45°C for 12 hours. In this process, the modified layered nanosilicate was dispersed in the polymer matrix, forming a nanobrick-gravel structure similar to that of sand. The polyacrylonitrile provided a rigid skeleton, the polymethyl methacrylate filled the pores, and the molecules of urea and melamine were evenly distributed between the polymer chains, which facilitated the subsequent heat treatment to generate porous or flame-retardant active sites. The result was a nanocomposite system with excellent dispersion stability, flame retardancy, and spinning fluidity, resulting in a spinning precursor solution. (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and then transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by an injection pump. The flow rate was set to 1.0 mL / h, the voltage was 18 kV, and the distance was 15 cm. The collected spun fibers were placed in a muffle furnace, first heated to 150 ° C at a rate of 2 ° C / min and kept warm for 30 minutes, and then oxidized in an air atmosphere at 250 ° C for 80 minutes. The stabilized fibers were placed in a tubular furnace and heated to 800 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 20% of the total gas flow. Carbonization was performed for 90 minutes and cooling was performed. A fiber structure with porous flame retardant sites on the surface was obtained by electrospinning and high-temperature carbonization. After pre-oxidation and carbonization, polyacrylonitrile formed a carbon fiber skeleton and retained nitrogen-doped active sites. The modified layered nanostructured fibers were Silicates are embedded in the fiber in the form of exfoliated nanosheets, which improves the stability of the structure after carbonization and prevents pore collapse. During the carbonization stage, ammonia penetration and the action of residual polyacrylonitrile molecules form a nitrogen-doped carbon network structure, forming a three-dimensional network in the plastic matrix, which not only inhibits the slippage of plastic molecular chains, but also improves the tensile strength and impact resistance of the material through stress transfer. At the same time, carbon fibers form a carbon layer during combustion, isolating oxygen and heat, delaying combustion, and nitrogen-doped sites promote the catalytic carbonization of polymers, forming a dense carbon layer and enhancing flame retardant properties. The physical barrier of the modified layered nanosilicates is also conducive to blocking gas diffusion and heat conduction, and the modified layered nanosilicates promote fiber dispersion, avoid agglomeration, and optimize the conductive path. Carbon fibers provide a conductive network, and nitrogen doping provides additional free electrons, reducing resistivity and improving conductive properties, thereby obtaining layered nanosilicate-loaded nitrogen-doped carbon nanofibers.

[0016] This embodiment provides a method for preparing a functional plastic fiber masterbatch material, which specifically includes the following steps: S1. Disperse 5.0 g of ammonium polyphosphate in 50 mL of anhydrous methanol and ultrasonically treat for 1 h to form dispersion I for standby use. Mix 650.0 mg of γ-cyclodextrin and 300.0 mg of potassium hydroxide in 30 mL of 30% methanol solution as solution II for standby use. Then dissolve Pluronic F127 and carboxylated carbon nanotubes in 30 mL of anhydrous methanol. The addition amounts of Pluronic F127 and carboxylated carbon nanotubes are 200.0 mg and 15.0 mg, respectively. The surface of carboxylated carbon nanotubes has carboxyl groups, which can interact with the hydrophilic chain segment PEO of Pluronic F127 through hydrogen bonds to form a more stable dispersion system, while the hydrophobic PPO chain segment wraps the non-polar region of the carbon tube to form a "micelle-nanotube" composite structure, further inhibiting agglomeration. Ultrasonicate for 30 min and use as solution III. Then add solution II and solution III dropwise to dispersion I at 25 ° C. The mixture was stirred for 3 hours, centrifuged, and the particles were collected and washed with anhydrous ethanol and anhydrous methanol for 5 times respectively, and dried in vacuum. Ammonium polyphosphate was used as the core to provide expansion flame retardant function. γ-cyclodextrin coated ammonium polyphosphate through hydrogen bonding or physical adsorption. One end of the amphiphilic block of PluronicF127 was combined with γ-cyclodextrin and the other end was connected to carboxylated carbon nanotubes to form a multi-layer stable coating, which improved the compatibility with the plastic matrix, avoided migration and precipitation during melt processing, and enhanced the interface stability. Among them, the carboxylated carbon nanotubes not only provided a nano-enhancement effect, which was beneficial to the improvement of mechanical properties, but also promoted the formation of a dense carbon layer, and synergistically enhanced the maze effect with γ-cyclodextrin, stabilized the carbon layer structure, and reduced the expansion of carbon layer cracks. The hydrophobic cavity of γ-cyclodextrin also constructed a barrier area with the hydrophilic outer wall to delay the escape of combustible gas. At the same time, the uniformly dispersed carboxylated carbon nanotubes can construct a conductive network on the surface of the composite, reduce the resistivity, and obtain γ-cyclodextrin modified composite particles. S2. The γ-cyclodextrin modified composite particles described in step S1 are dispersed in 100 mL of a 60% methanol solution by mass, and ultrasonically treated for 40 min to prepare a dispersion A for standby use. 90.0 mg of cobalt nitrate hexahydrate is dissolved in 80 mL of anhydrous methanol, and then 30.0 mg of zinc nitrate hexahydrate is added. The mild coordination effect of zinc ions reduces the brittleness caused by excessive cross-linking and makes the metal organic framework material more flexible, and does not deform during injection shearing. It is easy to break. During combustion, zinc ions are converted into nano-ZnO, filling the pores of the carbon layer to make it denser. In addition, the introduction of zinc ions narrows the band gap of the metal organic framework material. Its tetrahedral coordination configuration promotes interfacial contact with carboxylated carbon nanotubes and optimizes the percolation network, thereby enhancing the mechanical properties, flame retardancy and conductivity. As solution B, 0.3g of 3,5-diamino-1,2,4-triazole is dissolved in 50mL of anhydrous methanol as solution C. Then, solution B and solution C are prepared in the same manner. The precipitate was added dropwise to dispersion A, heated to 50°C, stirred for 3 hours, and centrifuged. The precipitate was washed with anhydrous methanol three times and finally immersed in a 1.0% oleic acid methanol solution for 30 minutes. The precipitate was taken out and supercritically dried. The composite particles modified with γ-cyclodextrin were used as the core layer, the middle layer was a Co / Zn bimetallic organic framework, and the outer layer was coated with oleic acid molecules, which improved the compatibility with the plastic matrix and presented a porous through-structure characteristic. The nanofiller function was better exerted through the hierarchical channel effect, restricting the movement of the plastic molecular chain and absorbing the impact energy by the deformation of the pore wall, significantly enhancing the mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposed into metal oxides at high temperature, catalyzing the polymer to form a dense carbon layer, isolating heat and oxygen, and extending the heat conduction and diffusion through the tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic atoms caused the increase of lattice stress and dislocation density, which promoted the conduction of electronic transitions, thereby also being beneficial to the improvement of flame retardancy and electrical conductivity, thus obtaining a multi-level composite functional material. S3, the layered nano-silicate loaded nitrogen-doped carbon nanofibers are annealed at 150°C. The annealing pretreatment can eliminate surface adsorbed water, stabilize nitrogen-containing functional groups, and avoid subsequent high-temperature extrusion decomposition to produce gas. Then, the multi-level composite functional material described in step S2 is first mixed, and then polypropylene, antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant consists of equal weights of antioxidant 1010 and antioxidant 168. The mixed material is then added to an extruder for melt extrusion and granulation. The feeding section temperature is controlled at 170°C and the melt extrusion temperature is 200°C. The layered nano-silicate loaded nitrogen-doped carbon nanofibers can be entangled on the surface of the multi-level composite functional material during the melt extrusion process to form an interpenetrating network. The polar groups introduced by nitrogen doping can form hydrogen bonds or coordination effects with the metal nodes of the multi-level composite functional material, thereby enhancing the interfacial bonding with the polypropylene matrix, which is beneficial to the improvement of the mechanical properties, flame retardancy and electrical conductivity of the plastic by the filler, broadening the application of the plastic, and obtaining a functional plastic fiber masterbatch material.

[0017] In this example, the prepared multi-layer composite functional material was subjected to scanning electron microscopy to observe its microscopic morphology. Figure 1 This is a 1000-fold magnified SEM image of the multi-layer composite functional material prepared in Example 1. Figure 1 The multi-layer composite functional material prepared in this embodiment presents a porous through-hole structure.

[0018] Example 2 This embodiment proposes a functional plastic fiber masterbatch material, comprising the following components in parts by weight: 5 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 10 parts of multi-level composite functional materials, 70 parts of polypropylene, 1 part of antioxidant, and 3 parts of calcium stearate.

[0019] The layered nano-silicate loaded nitrogen-doped carbon nanofiber is prepared from the following components in parts by weight: 1 part of modified layered nano-silicate, 6 parts of polyacrylonitrile, 1 part of polymethyl methacrylate, 1 part of urea, and 1 part of melamine.

[0020] The preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water. The amount of layered nanosilicate added is 0.5 g. When layered nanosilicate is used as a nanofiller for plastics, it can not only improve the flame retardancy of plastics through physical barrier and catalytic carbonization mechanism, but also improve the tensile strength, impact toughness and other mechanical properties of plastics. Ultrasonic treatment is carried out for 30 minutes to obtain a suspension for use. Then, 0.04 g of hexadecyltrimethylammonium bromide is dissolved in 20 mL of 40°C water and stirred until completely dissolved. Then, the hexadecyltrimethylammonium bromide solution is added dropwise to the suspension within 20 minutes while stirring. The suspension was stirred at 60°C for 24 hours and centrifuged at a speed of 12,000 rpm for 10 minutes. The precipitate was washed alternately with deionized water and ethanol solution three times, dried, and ground. Cetyltrimethylammonium bromide was inserted into the silicate interlayer through cation exchange, thereby expanding the interlayer spacing and facilitating the embedding of polymer molecular chains. At the same time, the long alkyl chains of cetyltrimethylammonium bromide covered the silicate surface, changing its hydrophilicity to hydrophobicity, improving its compatibility with the plastic matrix, and facilitating the strengthening, toughening, and flame retardant effects, thereby obtaining a modified layered nanosilicate. (2) The modified layered nanosilicate described in step (1) was dispersed in 10 mL of a mixed solvent of N,N-dimethylformamide and acetone, wherein the volume ratio of N,N-dimethylformamide to acetone was 7:3, and the mixture was stirred for 1 hour. Then, 0.1 g of urea and 0.1 g of melamine were added, and the mixture was stirred for 10 minutes. Then, polymethyl methacrylate was added in an amount of 0.1 g. Polymethyl methacrylate can reduce the viscosity of the spinning solution and improve the spinnability. At the same time, as a pore-forming auxiliary agent, the mixture was further optimized. The porous structure of the fiber was adjusted, and finally 0.6g of polyacrylonitrile was added and stirred at 40°C for 8h. In this process, the modified layered nanosilicate was dispersed in the polymer matrix to form a nanobrick-gravel structure. The polyacrylonitrile provided a rigid skeleton, the polymethyl methacrylate filled the pores, and the molecules of urea and melamine were evenly distributed between the polymer chains, which was conducive to the subsequent heat treatment to generate porous or flame-retardant active sites. The result was a nanocomposite system with excellent dispersion stability, flame retardancy and spinning fluidity, and a spinning precursor solution was obtained. (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and then transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by an injection pump. The flow rate was set to 0.8 mL / h, the voltage was 12 kV, and the distance was 12 cm. The collected spinning fibers were placed in a muffle furnace, first heated to 130 ° C at a rate of 2 ° C / min and kept warm for 30 minutes, and then oxidized in an air atmosphere at 240 ° C for 70 minutes. The stabilized fibers were placed in a tubular furnace and heated to 700 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 10% of the total gas flow. Carbonization was performed for 70 minutes and cooling was performed. A fiber structure with porous flame retardant sites on the surface was obtained by electrospinning and high-temperature carbonization. After pre-oxidation and carbonization, polyacrylonitrile formed a carbon fiber skeleton and retained nitrogen-doped active sites. The modified layered nanostructured fibers were Silicates are embedded in the fiber in the form of exfoliated nanosheets, which improves the stability of the structure after carbonization and prevents pore collapse. During the carbonization stage, ammonia penetration and the action of residual polyacrylonitrile molecules form a nitrogen-doped carbon network structure, forming a three-dimensional network in the plastic matrix, which not only inhibits the slippage of plastic molecular chains, but also improves the tensile strength and impact resistance of the material through stress transfer. At the same time, carbon fibers form a carbon layer during combustion, isolating oxygen and heat, delaying combustion, and nitrogen-doped sites promote the catalytic carbonization of polymers, forming a dense carbon layer and enhancing flame retardant properties. The physical barrier of the modified layered nanosilicates is also conducive to blocking gas diffusion and heat conduction, and the modified layered nanosilicates promote fiber dispersion, avoid agglomeration, and optimize the conductive path. Carbon fibers provide a conductive network, and nitrogen doping provides additional free electrons, reducing resistivity and improving conductive properties, thereby obtaining layered nanosilicate-loaded nitrogen-doped carbon nanofibers.

[0021] This embodiment provides a method for preparing a functional plastic fiber masterbatch material, which specifically includes the following steps: S1, 4.0g of ammonium polyphosphate was dispersed in 50mL of anhydrous methanol and ultrasonically treated for 0.5h to form dispersion I for standby use, 600.0mg of γ-cyclodextrin and 200.0mg of potassium hydroxide were mixed in 30mL of 30% methanol solution by mass to form solution II for standby use, and PluronicF127 and carboxylated carbon nanotubes were dissolved in 30mL of anhydrous methanol, with the addition amounts of PluronicF127 and carboxylated carbon nanotubes being 150.0mg and 10.0mg, respectively. The surface of carboxylated carbon nanotubes has carboxyl groups, which can interact with the hydrophilic chain segment PEO of PluronicF127 through hydrogen bonds to form a more stable dispersion system, while the hydrophobic PPO chain segment wraps the non-polar region of the carbon tube to form a "micelle-nanotube" composite structure, further inhibiting agglomeration, and ultrasonicated for 20min to form solution III for standby use, and then solution II and solution III were added dropwise to dispersion I for 25 The mixture was stirred at 400 °C for 2 h, centrifuged, and the particles were collected and washed three times with anhydrous ethanol and anhydrous methanol respectively, and dried in vacuum. Ammonium polyphosphate was used as the core to provide expansion flame retardant function. γ-cyclodextrin coated ammonium polyphosphate through hydrogen bonding or physical adsorption. One end of the amphiphilic block of PluronicF127 was bound to γ-cyclodextrin and the other end was connected to carboxylated carbon nanotubes to form a multi-layer stable coating, which improved the compatibility with the plastic matrix, avoided migration and precipitation during melt processing, and enhanced the interface stability. Among them, the carboxylated carbon nanotubes not only provided a nano-enhancement effect, which was beneficial to the improvement of mechanical properties, but also promoted the formation of a dense carbon layer, and synergistically enhanced the maze effect with γ-cyclodextrin, stabilized the carbon layer structure, and reduced the propagation of carbon layer cracks. The hydrophobic cavity of γ-cyclodextrin also constructed a barrier zone with the hydrophilic outer wall to delay the escape of combustible gas. At the same time, the uniformly dispersed carboxylated carbon nanotubes could construct a conductive network on the surface of the composite, reducing the resistivity, and obtaining γ-cyclodextrin-modified composite particles. S2. The γ-cyclodextrin modified composite particles described in step S1 are dispersed in 100 mL of a 60% methanol solution by mass, and ultrasonically treated for 30 min to prepare a dispersion A for standby use. 80.0 mg of cobalt nitrate hexahydrate is dissolved in 80 mL of anhydrous methanol, and then 20.0 mg of zinc nitrate hexahydrate is added. The mild coordination effect of zinc ions reduces the brittleness caused by excessive cross-linking and makes the metal organic framework material more flexible, and does not deform during injection shearing. It is easy to break. During combustion, zinc ions are converted into nano-ZnO, filling the pores of the carbon layer to make it denser. In addition, the introduction of zinc ions narrows the band gap of the metal organic framework material. Its tetrahedral coordination configuration promotes interfacial contact with carboxylated carbon nanotubes and optimizes the percolation network, thereby enhancing the mechanical properties, flame retardancy and conductivity. As solution B, 0.2g of 3,5-diamino-1,2,4-triazole is dissolved in 50mL of anhydrous methanol as solution C. Then, solution B and solution C are prepared in the same manner. The precipitate was added dropwise to dispersion A, heated to 40°C, stirred for 2h, centrifuged, and washed with anhydrous methanol three times. Finally, it was immersed in a 0.5% oleic acid methanol solution for 20min, taken out, and supercritical dried. The composite particles modified with γ-cyclodextrin were used as the core layer, the middle layer was a Co / Zn bimetallic organic framework, and the outer layer was coated with oleic acid molecules, which improved the compatibility with the plastic matrix and presented a porous through-structure characteristic. The nanofiller function was better exerted through the hierarchical channel effect, restricting the movement of the plastic molecular chain and absorbing the impact energy by the deformation of the pore wall, significantly enhancing the mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposed into metal oxides at high temperature, catalyzing the polymer to form a dense carbon layer, isolating heat and oxygen, and extending the conduction and diffusion of heat through the tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic atoms caused the increase of lattice stress and dislocation density, which promoted the conduction of electronic transitions, and thus was also beneficial to the improvement of flame retardancy and electrical conductivity, thus obtaining a multi-level composite functional material. S3, the layered nano-silicate loaded nitrogen-doped carbon nanofibers are annealed at 130°C. The annealing pretreatment can eliminate surface adsorbed water, stabilize nitrogen-containing functional groups, and avoid subsequent high-temperature extrusion decomposition to produce gas. Then, the fibers are mixed with the multi-level composite functional material described in step S2, and then polypropylene, antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant consists of antioxidant 1010 and antioxidant 168 of equal weight. Then, the mixture is added to an extruder for melt extrusion and granulation. The feeding section temperature is controlled at 160°C and the melt extrusion temperature is 180°C. The layered nano-silicate loaded nitrogen-doped carbon nanofibers can be entangled on the surface of the multi-level composite functional material during the melt extrusion process to form an interpenetrating network. The polar groups introduced by nitrogen doping can form hydrogen bonds or coordination effects with the metal nodes of the multi-level composite functional material, thereby enhancing the interfacial bonding with the polypropylene matrix, which is beneficial to the improvement of the mechanical properties, flame retardancy, and electrical conductivity of the plastic by the filler, broadening the application of the plastic, and obtaining a functional plastic fiber masterbatch material.

[0022] Example 3 This embodiment proposes a functional plastic fiber masterbatch material, comprising the following components in parts by weight: 7.5 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 15 parts of multi-level composite functional materials, 80 parts of polypropylene, 2 parts of antioxidants, and 4 parts of calcium stearate.

[0023] The layered nano-silicate loaded nitrogen-doped carbon nanofiber is prepared from the following components in parts by weight: 1.5 parts of modified layered nano-silicate, 8 parts of polyacrylonitrile, 3 parts of polymethyl methacrylate, 1.5 parts of urea, and 1.5 parts of melamine.

[0024] The preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water. The amount of layered nanosilicate added is 0.75 g. When layered nanosilicate is used as a nanofiller for plastics, it can not only improve the flame retardancy of plastics through physical barrier and catalytic carbonization mechanism, but also improve the tensile strength, impact toughness and other mechanical properties of plastics. Ultrasonic treatment is performed for 40 minutes to obtain a suspension for use. Then, 0.07 g of hexadecyltrimethylammonium bromide is dissolved in 20 mL of 45°C water and stirred until completely dissolved. Then, the hexadecyltrimethylammonium bromide solution is added dropwise to the suspension within 25 minutes while stirring. The suspension was stirred at 65°C for 24 hours and centrifuged at a speed of 14,000 rpm for 12.5 minutes. The precipitate was washed alternately with deionized water and ethanol solution three times, dried, and ground. Cetyltrimethylammonium bromide was inserted into the silicate interlayer through cation exchange, thereby expanding the interlayer spacing and facilitating the embedding of polymer molecular chains. At the same time, the long alkyl chains of cetyltrimethylammonium bromide covered the silicate surface, changing its hydrophilicity to hydrophobicity, improving its compatibility with the plastic matrix, and facilitating the strengthening, toughening, and flame retardant effects, thereby obtaining a modified layered nanosilicate. (2) The modified layered nanosilicate described in step (1) was dispersed in 10 mL of a mixed solvent of N,N-dimethylformamide and acetone, wherein the volume ratio of N,N-dimethylformamide to acetone was 7:3, and the mixture was stirred for 1.5 h. Then, 0.15 g of urea and 0.15 g of melamine were added, and the mixture was stirred for 15 min. Then, polymethyl methacrylate was added in an amount of 0.3 g. Polymethyl methacrylate can reduce the viscosity of the spinning solution and improve the spinnability. At the same time, as a pore-forming auxiliary agent, it can further improve the spinnability. The porous structure of the fiber was adjusted by chemical reaction, and finally 0.8g polyacrylonitrile was added and stirred at 42.5℃ for 10h. In this process, the modified layered nanosilicate was dispersed in the polymer matrix to form a nanobrick-gravel structure. The polyacrylonitrile provided a rigid skeleton, the polymethyl methacrylate filled the pores, and the molecules of urea and melamine were evenly distributed between the polymer chains, which was conducive to the subsequent heat treatment to generate porous or flame retardant active sites. The nanocomposite system with excellent dispersion stability, flame retardancy and spinning fluidity was prepared, and the spinning precursor solution was obtained. (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and then transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by an injection pump. The flow rate was set to 0.9 mL / h, the voltage was 15 kV, and the distance was 13.5 cm. The collected spun fibers were placed in a muffle furnace, first heated to 140 ° C at a rate of 2 ° C / min and kept warm for 30 minutes, and then oxidized in an air atmosphere at 245 ° C for 75 minutes. The stabilized fibers were placed in a tubular furnace and heated to 750 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 15% of the total gas flow. Carbonization was performed for 80 minutes and cooling was performed. A fiber structure with porous flame retardant sites on the surface was obtained by electrospinning and high-temperature carbonization. After pre-oxidation and carbonization, polyacrylonitrile formed a carbon fiber skeleton and retained nitrogen-doped active sites. The modified layered nanostructured fibers were Nanosilicate is embedded in the fiber in the form of exfoliated nanosheets, which improves the stability of the structure after carbonization and prevents pore collapse. During the carbonization stage, a nitrogen-doped carbon network structure is formed under the action of ammonia penetration and residual polyacrylonitrile molecules, forming a three-dimensional network in the plastic matrix, which not only inhibits the slippage of plastic molecular chains, but also improves the tensile strength and impact resistance of the material through stress transfer. At the same time, carbon fibers form a carbon layer during combustion, isolating oxygen and heat, delaying combustion, and nitrogen-doped sites promote the catalytic carbonization of polymers, forming a dense carbon layer and enhancing flame retardant properties. The physical barrier of modified layered nanosilicates is also conducive to blocking gas diffusion and heat conduction, and the modified layered nanosilicates promote fiber dispersion, avoid agglomeration, and optimize conductive paths. Carbon fibers provide a conductive network, and nitrogen doping provides additional free electrons, reducing resistivity and improving conductive properties, thereby obtaining layered nanosilicate-loaded nitrogen-doped carbon nanofibers.

[0025] This embodiment provides a method for preparing a functional plastic fiber masterbatch material, which specifically includes the following steps: S1, 4.5g of ammonium polyphosphate was dispersed in 50mL of anhydrous methanol and ultrasonically treated for 0.75h to form dispersion I for standby use, 625.0mg of γ-cyclodextrin and 250.0mg of potassium hydroxide were mixed in 30mL of 30% methanol solution by mass to form solution II for standby use, and PluronicF127 and carboxylated carbon nanotubes were dissolved in 30mL of anhydrous methanol, the addition amounts of PluronicF127 and carboxylated carbon nanotubes were 175.0mg and 12.5mg respectively. The surface of carboxylated carbon nanotubes has carboxyl groups, which can interact with the hydrophilic chain segment PEO of PluronicF127 through hydrogen bonds to form a more stable dispersion system, while the hydrophobic PPO chain segment wraps the non-polar region of the carbon tube to form a "micelle-nanotube" composite structure, further inhibiting agglomeration, and ultrasonicated for 25min to form solution III for standby use, and then solution II and solution III were added dropwise to dispersion I for 25min. The mixture was stirred at 400 °C for 2.5 h, centrifuged, and the particles were collected and washed four times with anhydrous ethanol and anhydrous methanol respectively, and dried in vacuum. Ammonium polyphosphate was used as the core to provide expansion flame retardant function. γ-cyclodextrin coated ammonium polyphosphate through hydrogen bonding or physical adsorption. One end of the amphiphilic block of PluronicF127 was bound to γ-cyclodextrin and the other end was connected to carboxylated carbon nanotubes to form a multi-layer stable coating, which improved the compatibility with the plastic matrix, avoided migration and precipitation during melt processing, and enhanced the interface stability. Among them, the carboxylated carbon nanotubes not only provided a nano-enhancement effect, which was beneficial to the improvement of mechanical properties, but also promoted the formation of a dense carbon layer, and synergistically enhanced the maze effect with γ-cyclodextrin, stabilized the carbon layer structure, and reduced the propagation of carbon layer cracks. The hydrophobic cavity of γ-cyclodextrin also constructed a barrier zone with the hydrophilic outer wall to delay the escape of combustible gas. At the same time, the uniformly dispersed carboxylated carbon nanotubes could construct a conductive network on the surface of the composite, reducing the resistivity, and obtaining γ-cyclodextrin-modified composite particles. S2. The γ-cyclodextrin modified composite particles described in step S1 are dispersed in 100 mL of a 60% methanol solution by mass, and ultrasonically treated for 35 min to prepare a dispersion A for standby use. 85.0 mg of cobalt nitrate hexahydrate is dissolved in 80 mL of anhydrous methanol, and then 25.0 mg of zinc nitrate hexahydrate is added. The mild coordination effect of zinc ions reduces the brittleness caused by excessive cross-linking and makes the metal organic framework material more flexible and not easily sheared during injection molding. Crushed, zinc ions are converted into nano-ZnO during combustion, filling the pores of the carbon layer to make it denser, and the introduction of zinc ions narrows the band gap of the metal organic framework material. Its tetrahedral coordination configuration promotes interfacial contact with carboxylated carbon nanotubes, optimizes the percolation network, and thus enhances mechanical properties, flame retardancy and conductivity. As solution B, 0.25g of 3,5-diamino-1,2,4-triazole is dissolved in 50mL of anhydrous methanol as solution C, and then solution B and solution C are sequentially added. The mixture was added dropwise to dispersion A, heated to 45°C, stirred for 2.5 hours, and centrifuged. The precipitate was washed three times with anhydrous methanol and finally immersed in a 0.75% oleic acid methanol solution for 25 minutes. The mixture was taken out and supercritically dried. The composite particles modified with γ-cyclodextrin were used as the core layer, the middle layer was a Co / Zn bimetallic organic framework, and the outer layer was coated with oleic acid molecules, which improved the compatibility with the plastic matrix and presented a porous through-hole structure. The nanofiller function was better exerted through the hierarchical channel effect, restricting the movement of the plastic molecular chain. The impact energy was absorbed by the deformation of the pore wall, significantly enhancing the mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposed into metal oxides at high temperature, catalyzing the polymer to form a dense carbon layer, isolating heat and oxygen, and extending the conduction and diffusion of heat through the tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic atoms caused an increase in lattice stress and dislocation density, promoting electron transition conduction, and thus also conducive to the improvement of flame retardancy and electrical conductivity, thus obtaining a multi-level composite functional material. S3, the layered nano-silicate loaded nitrogen-doped carbon nanofibers are annealed at 140 ° C. The annealing pretreatment can eliminate surface adsorbed water, stabilize nitrogen-containing functional groups, and avoid subsequent high-temperature extrusion decomposition to produce gas, and then mixed with the multi-level composite functional material described in step S2, and then polypropylene, antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant consists of antioxidant 1010 and antioxidant 168 of equal weight. The mixed material is then added to the extruder for melt extrusion and granulation, and the feeding section temperature is controlled at 165 ° C and the melt extrusion temperature is 190 ° C. The layered nano-silicate loaded nitrogen-doped carbon nanofibers can be entangled on the surface of the multi-level composite functional material during the melt extrusion process to form an interpenetrating network. The polar groups introduced by nitrogen doping can form hydrogen bonds or coordination effects with the metal nodes of the multi-level composite functional material, thereby enhancing the interface binding with the polypropylene matrix, which is beneficial to the improvement of the mechanical properties, flame retardancy and conductivity of the plastic by the filler, broadening the application of the plastic, and obtaining a functional plastic fiber masterbatch material.

[0026] Example 4 This embodiment proposes a functional plastic fiber masterbatch material, comprising the following components in parts by weight: 10 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 10 parts of multi-level composite functional materials, 90 parts of polypropylene, 3 parts of antioxidants, and 5 parts of calcium stearate.

[0027] The layered nano-silicate loaded nitrogen-doped carbon nanofiber is prepared from the following components in parts by weight: 2 parts of modified layered nano-silicate, 6 parts of polyacrylonitrile, 1 part of polymethyl methacrylate, 2 parts of urea, and 2 parts of melamine.

[0028] The preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water. The amount of layered nanosilicate added is 1.0 g. When layered nanosilicate is used as a nanofiller for plastics, it can not only improve the flame retardancy of plastics through physical barrier and catalytic carbonization mechanism, but also improve the tensile strength, impact toughness and other mechanical properties of plastics. Ultrasonic treatment is performed for 30 minutes to obtain a suspension for use. Then, 0.04 g of hexadecyltrimethylammonium bromide is dissolved in 20 mL of 50°C water and stirred until completely dissolved. Then, the hexadecyltrimethylammonium bromide solution is added dropwise to the suspension within 30 minutes while stirring. The suspension was stirred at 70°C for 24 hours and centrifuged at a speed of 16,000 rpm for 10 minutes. The precipitate was washed alternately with deionized water and ethanol solution three times, dried, and ground. Cetyltrimethylammonium bromide was inserted into the silicate interlayer through cation exchange, thereby expanding the interlayer spacing and facilitating the embedding of polymer molecular chains. At the same time, the long alkyl chains of cetyltrimethylammonium bromide covered the silicate surface, changing its hydrophilicity to hydrophobicity, improving its compatibility with the plastic matrix, and facilitating the strengthening, toughening, and flame retardant effects, thereby obtaining a modified layered nanosilicate. (2) The modified layered nanosilicate described in step (1) was dispersed in 10 mL of a mixed solvent of N,N-dimethylformamide and acetone, wherein the volume ratio of N,N-dimethylformamide to acetone was 7:3, and the mixture was stirred for 1 hour. Then, 0.2 g of urea and 0.2 g of melamine were added, and the mixture was stirred for 10 minutes. Then, polymethyl methacrylate was added in an amount of 0.1 g. Polymethyl methacrylate can reduce the viscosity of the spinning solution and improve the spinnability. At the same time, as a pore-forming auxiliary agent, the reaction mixture was further optimized. The porous structure of the fiber was adjusted, and finally 0.6g of polyacrylonitrile was added and stirred at 45°C for 8h. In this process, the modified layered nanosilicate was dispersed in the polymer matrix to form a nanobrick-gravel structure. The polyacrylonitrile provided a rigid skeleton, the polymethyl methacrylate filled the pores, and the molecules of urea and melamine were evenly distributed between the polymer chains, which was conducive to the subsequent heat treatment to generate porous or flame-retardant active sites. The result was a nanocomposite system with excellent dispersion stability, flame retardancy and spinning fluidity, and a spinning precursor solution was obtained. (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by an injection pump. The flow rate was set to 1.0 mL / h, the voltage was 18 kV, and the distance was 15 cm. The collected spun fibers were placed in a muffle furnace, first heated to 150 ° C at a rate of 2 ° C / min and kept warm for 30 minutes, and then oxidized in an air atmosphere at 250 ° C for 70 minutes. The stabilized fibers were placed in a tubular furnace and heated to 800 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 10% of the total gas flow. Carbonization was performed for 90 minutes and cooling was performed. A fiber structure with porous flame retardant sites on the surface was obtained by electrospinning and high-temperature carbonization. After pre-oxidation and carbonization, polyacrylonitrile formed a carbon fiber skeleton and retained nitrogen-doped active sites. The modified layered nanostructured fibers were Silicates are embedded in the fiber in the form of exfoliated nanosheets, which improves the stability of the structure after carbonization and prevents pore collapse. During the carbonization stage, ammonia penetration and the action of residual polyacrylonitrile molecules form a nitrogen-doped carbon network structure, forming a three-dimensional network in the plastic matrix, which not only inhibits the slippage of plastic molecular chains, but also improves the tensile strength and impact resistance of the material through stress transfer. At the same time, carbon fibers form a carbon layer during combustion, isolating oxygen and heat, delaying combustion, and nitrogen-doped sites promote the catalytic carbonization of polymers, forming a dense carbon layer and enhancing flame retardant properties. The physical barrier of the modified layered nanosilicates is also conducive to blocking gas diffusion and heat conduction, and the modified layered nanosilicates promote fiber dispersion, avoid agglomeration, and optimize the conductive path. Carbon fibers provide a conductive network, and nitrogen doping provides additional free electrons, reducing resistivity and improving conductive properties, thereby obtaining layered nanosilicate-loaded nitrogen-doped carbon nanofibers.

[0029] This embodiment provides a method for preparing a functional plastic fiber masterbatch material, which specifically includes the following steps: S1, 5.0g of ammonium polyphosphate was dispersed in 50mL of anhydrous methanol and ultrasonically treated for 0.5h to form dispersion I for standby use, 600.0mg of γ-cyclodextrin and 300.0mg of potassium hydroxide were mixed in 30mL of 30% methanol solution by mass to prepare solution II for standby use, and PluronicF127 and carboxylated carbon nanotubes were dissolved in 30mL of anhydrous methanol, with the addition amounts of PluronicF127 and carboxylated carbon nanotubes being 150.0mg and 15.0mg respectively. The surface of carboxylated carbon nanotubes has carboxyl groups, which can interact with the hydrophilic chain segment PEO of PluronicF127 through hydrogen bonds to form a more stable dispersion system, while the hydrophobic PPO chain segment wraps the non-polar region of the carbon tube to form a "micelle-nanotube" composite structure, further inhibiting agglomeration, and ultrasonicated for 20min to prepare solution III for standby use, and then solution II and solution III were added dropwise to dispersion I for 25min. The mixture was stirred at 400 °C for 2 h, centrifuged, and the particles were collected and washed 5 times with anhydrous ethanol and anhydrous methanol respectively, and dried in vacuum. Ammonium polyphosphate was used as the core to provide expansion flame retardant function. γ-cyclodextrin coated ammonium polyphosphate through hydrogen bonding or physical adsorption. One end of the amphiphilic block of PluronicF127 was combined with γ-cyclodextrin and the other end was connected to carboxylated carbon nanotubes to form a multi-layer stable coating, which improved the compatibility with the plastic matrix, avoided migration and precipitation during melt processing, and enhanced the interface stability. Among them, the carboxylated carbon nanotubes not only provided a nano-enhancement effect, which was beneficial to the improvement of mechanical properties, but also promoted the formation of a dense carbon layer, and synergistically enhanced the maze effect with γ-cyclodextrin, stabilized the carbon layer structure, and reduced the propagation of carbon layer cracks. The hydrophobic cavity of γ-cyclodextrin also constructed a barrier zone with the hydrophilic outer wall to delay the escape of combustible gas. At the same time, the uniformly dispersed carboxylated carbon nanotubes could construct a conductive network on the surface of the composite, reducing the resistivity, and obtaining γ-cyclodextrin-modified composite particles. S2. The γ-cyclodextrin modified composite particles described in step S1 are dispersed in 100 mL of a 60% methanol solution by mass, and ultrasonically treated for 30 min to prepare a dispersion A for standby use. 90.0 mg of cobalt nitrate hexahydrate is dissolved in 80 mL of anhydrous methanol, and then 20.0 mg of zinc nitrate hexahydrate is added. The mild coordination effect of zinc ions reduces the brittleness caused by excessive cross-linking and makes the metal organic framework material more flexible, and does not deform during injection shearing. It is easy to break. During combustion, zinc ions are converted into nano-ZnO, filling the pores of the carbon layer to make it denser. In addition, the introduction of zinc ions narrows the band gap of the metal organic framework material. Its tetrahedral coordination configuration promotes interfacial contact with carboxylated carbon nanotubes and optimizes the percolation network, thereby enhancing the mechanical properties, flame retardancy and conductivity. As solution B, 0.3g of 3,5-diamino-1,2,4-triazole is dissolved in 50mL of anhydrous methanol as solution C. Then, solution B and solution C are prepared in the same manner. The precipitate was added dropwise to dispersion A, heated to 50°C, stirred for 2h, centrifuged, and washed with anhydrous methanol three times. Finally, it was immersed in a 1.0% oleic acid methanol solution for 20min, taken out, and supercritical dried. The composite particles modified with γ-cyclodextrin were used as the core layer, the middle layer was a Co / Zn bimetallic organic framework, and the outer layer was coated with oleic acid molecules, which improved the compatibility with the plastic matrix and presented a porous through-structure. The nanofiller function was better exerted through the hierarchical channel effect, restricting the movement of the plastic molecular chain and absorbing the impact energy by the deformation of the pore wall, significantly enhancing the mechanical properties. At the same time, the Co / Zn bimetallic organic framework decomposed into metal oxides at high temperature, catalyzing the polymer to form a dense carbon layer, isolating heat and oxygen, and extending the conduction and diffusion of heat through the tortuous porous channels. The difference in atomic radius of the Co / Zn bimetallic atoms caused the increase of lattice stress and dislocation density, which promoted the conduction of electronic transitions, thereby also being beneficial to the improvement of flame retardancy and electrical conductivity, thus obtaining a multi-level composite functional material. S3, the layered nano-silicate loaded nitrogen-doped carbon nanofibers are annealed at 150 ° C. The annealing pretreatment can eliminate surface adsorbed water, stabilize nitrogen-containing functional groups, and avoid subsequent high-temperature extrusion decomposition to produce gas, and then mixed with the multi-level composite functional material described in step S2, and then polypropylene, antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant consists of antioxidant 1010 and antioxidant 168 of equal weight. The mixed material is then added to the extruder for melt extrusion and granulation, and the feeding section temperature is controlled at 170 ° C and the melt extrusion temperature is 180 ° C. The layered nano-silicate loaded nitrogen-doped carbon nanofibers can be entangled on the surface of the multi-level composite functional material during the melt extrusion process to form an interpenetrating network. The polar groups introduced by nitrogen doping can form hydrogen bonds or coordination effects with the metal nodes of the multi-level composite functional material, thereby enhancing the interface binding with the polypropylene matrix, which is beneficial to the improvement of the mechanical properties, flame retardancy and conductivity of the plastic by the filler, broadening the application of the plastic, and obtaining a functional plastic fiber masterbatch material.

[0030] Comparative Example 1 This comparative example provides a functional plastic fiber masterbatch material, which differs from Example 1 in that the layered nanosilicate-loaded nitrogen-doped carbon nanofibers do not contain polyacrylonitrile, and no ammonia is introduced during the carbonization process; in the preparation method of the layered nanosilicate-loaded nitrogen-doped carbon nanofibers, polyacrylonitrile is not added in step (2), and only nitrogen is introduced during the carbonization process in step (3), without ammonia; the preparation method of the functional plastic fiber masterbatch material is the same as that of Example 1.

[0031] Comparative Example 2 This comparative example provides a functional plastic fiber masterbatch material, which differs from Example 1 in that the multi-level composite functional material does not contain Pluronic F127; the preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers is the same as that of Example 1; and Pluronic F127 is not added in step S1 of the preparation method of the functional plastic fiber masterbatch material.

[0032] Comparative Example 3 This comparative example provides a functional plastic fiber masterbatch material, which differs from Example 1 in that the multi-level composite functional material does not contain a Co / Zn bimetallic organic framework; the preparation method of layered nanosilicate-loaded nitrogen-doped carbon nanofibers is the same as that in Example 1; and cobalt nitrate hexahydrate, zinc nitrate hexahydrate, and 3,5-diamino-1,2,4-triazole are not added in step S2 of the preparation method of the functional plastic fiber masterbatch material.

[0033] Experimental Example 1 Mechanical properties test Test sample: functional plastic fiber masterbatch material prepared in Examples 1-4 and Comparative Examples 1-3.

[0034] Test method: The test sample is injected into a molding machine to prepare a standard specimen (GB / T17037.1-2019) for mechanical property testing. The tensile properties are tested in accordance with the standard GB / T1040.1-2018, and the impact strength is tested by measuring the cantilever beam notched impact strength in accordance with the provisions of the standard GB / T1843-2008.

[0035] Figure 2 The mechanical properties of Examples 1-4 and Comparative Examples 1-3 are shown in the figure. As shown in the figure, the tensile strength and impact strength of Examples 1-4 are 96-105MPa and 23.8-25.6KJ / m 2 , indicating strong mechanical properties; the tensile strength and impact strength of Comparative Examples 1-3 were 71-82MPa, 14.1-18.7KJ / m 2 , indicating that the mechanical properties are general; the layered nanosilicate-loaded nitrogen-doped carbon nanofibers of Comparative Example 1 do not contain polyacrylonitrile, and no ammonia is introduced during the carbonization process, so a porous carbon fiber skeleton cannot be formed, which is not conducive to inhibiting the slippage of the plastic molecular chain and improving the tensile strength and impact resistance of the material through stress transfer, resulting in general mechanical properties; the multi-level composite functional material of Comparative Example 2 does not contain PluronicF127, and cannot connect γ-cyclodextrin and carboxylated carbon nanotubes through amphiphilic blocks, which is not conducive to interface stability and the agglomeration of carboxylated carbon nanotubes cannot be inhibited, resulting in general mechanical properties; the multi-level composite functional material of Comparative Example 3 does not contain Co / Zn bimetallic organic framework, which is not conducive to the formation of a porous through-composite structure, limits the filling effect of the hierarchical channel, is not conducive to inhibiting the movement of the plastic molecular chain, and results in general mechanical properties.

[0036] Experimental Example 2 Flame retardant performance test Test sample: functional plastic fiber masterbatch material prepared in Examples 1-4 and Comparative Examples 1-3.

[0037] Test method: The test sample is injected into a molding machine to prepare a standard specimen (100mm×10mm×4mm). Then, the limiting oxygen index test is performed according to the standard GB / T2406.2-2009 "Determination of combustion behavior of plastics by oxygen index method". The higher the limiting oxygen index (%), the better the flame retardancy.

[0038] Figure 3The limiting oxygen index results of Examples 1-4 and Comparative Examples 1-3 are shown in FIG. As shown in the figure, the limiting oxygen index of Examples 1-4 is 29-33%, indicating good flame retardancy; the limiting oxygen index of Comparative Examples 1-3 is 16-25%, indicating general flame retardancy; the layered nano-silicate-loaded nitrogen-doped carbon nanofibers of Comparative Example 1 do not contain polyacrylonitrile, and ammonia is not introduced during the carbonization process, so a carbon fiber structure with porous flame retardant sites cannot be formed, and thus a dense carbon layer cannot be formed during combustion, resulting in general flame retardancy; Comparative Example The multi-level composite functional material of Example 2 does not contain Pluronic F127, which cannot inhibit the agglomeration of carboxylated carbon nanotubes, is not conducive to promoting the formation of a dense carbon layer, reduces the maze effect of carboxylated carbon nanotubes and γ-cyclodextrin, is not conducive to stabilizing the carbon layer structure, and results in average flame retardancy; the multi-level composite functional material of Comparative Example 3 does not contain Co / Zn bimetallic organic framework, cannot decompose into metal oxides at high temperature, is not conducive to catalyzing the formation of a dense carbon layer and isolating heat and oxygen, resulting in average flame retardancy.

[0039] Experimental Example 3 Conductivity experiment Test sample: functional plastic fiber masterbatch material prepared in Examples 1-4 and Comparative Examples 1-3.

[0040] Test method: Prepare the test sample into a standard disc specimen (50 mm in diameter and 3 mm in thickness). Then perform a volume resistivity test according to the plastic resistivity test standard GB / T1410-2006 to obtain the volume resistivity (Ω·cm).

[0041] Figure 4 The volume resistivity results of Examples 1-4 and Comparative Examples 1-3 are shown in the figure; as shown in the figure, the volume resistivity of Examples 1-4 is 12-21Ω·cm, indicating better conductivity; the volume resistivity of Comparative Examples 1-3 is 43-65Ω·cm, indicating general conductivity; the layered nanosilicate-loaded nitrogen-doped carbon nanofibers of Comparative Example 1 do not contain polyacrylonitrile, and no ammonia is introduced during the carbonization process, so carbon fibers that can provide a conductive network cannot be formed, and there are no nitrogen-doping sites that can provide additional free electrons, resulting in general conductivity; the multi-level composite functional material of Comparative Example 2 does not contain PluronicF127, which is not conducive to the uniform dispersion of carboxylated carbon nanotubes and the optimization of the conductive network, resulting in general conductivity; the multi-level composite functional material of Comparative Example 3 does not contain Co / Zn bimetallic organic framework, and cannot induce lattice stress and dislocation density to increase through the difference in bimetallic atomic radius, which is not conducive to promoting electron transition conduction, resulting in general conductivity.

[0042] The above experimental results show that the mechanical properties, flame retardant properties and conductive properties of Examples 1-4 of the present invention are significantly better than those of the samples of Comparative Examples 1-3. Among them, Example 1 using layered nanosilicate-loaded nitrogen-doped carbon nanofibers and multi-level composite functional materials has stronger mechanical properties, better flame retardant properties and better conductivity. The combination of layered nanosilicate-loaded nitrogen-doped carbon nanofibers and multi-level composite functional materials not only enhances the interfacial compatibility and bonding with the polypropylene matrix, but also synergistically enhances the mechanical properties, flame retardant properties and conductive properties of the plastic through the formed interpenetrating network structure.

[0043] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0044] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A functional plastic fiber masterbatch material, characterized by: The functional plastic fiber masterbatch material comprises the following components in parts by weight: 5-10 parts of layered nanosilicate-loaded nitrogen-doped carbon nanofibers, 10-20 parts of multi-level composite functional materials, 70-90 parts of polypropylene, 1-3 parts of antioxidants, and 3-5 parts of calcium stearate; the layered nanosilicate-loaded nitrogen-doped carbon nanofibers are made of the following components in parts by weight: 1-2 parts of modified layered nanosilicates, 6-10 parts of polyacrylonitrile, 1-5 parts of polymethyl methacrylate, 1-2 parts of urea, and 1-2 parts of melamine.

2. A method for preparing the functional plastic fiber masterbatch material according to claim 1, characterized in that: The specific steps include: S1. Disperse 4.0-5.0 g of ammonium polyphosphate in 50 mL of anhydrous methanol and ultrasonically treat for 0.5-1 h to form dispersion I for standby use. Mix 600.0-650.0 mg of γ-cyclodextrin and 200.0-300.0 mg of potassium hydroxide in 30 mL of a 30% methanol solution to form solution II for standby use. Dissolve Pluronic F127 and carboxylated carbon nanotubes in 30 mL of anhydrous methanol and ultrasonicate for 20-30 min to form solution III for standby use. Then, solution II and solution III are added dropwise to dispersion I in sequence, stirred at 25° C. for 2-3 h, centrifuged, and the particles are collected. The particles are washed 3-5 times with anhydrous ethanol and anhydrous methanol, respectively, and vacuum dried to obtain γ-cyclodextrin-modified composite particles. S2. Disperse the γ-cyclodextrin modified composite particles described in step S1 in 100 mL of a 60% methanol solution by mass, ultrasonically treat for 30-40 min, and use as dispersion A. Dissolve 80.0-90.0 mg of cobalt nitrate hexahydrate in 80 mL of anhydrous methanol, and then add zinc nitrate hexahydrate to use as solution B. Dissolve 0.2-0.3 g of 3,5-diamino-1,2,4-triazole in 50 mL of anhydrous methanol to use as solution C. Then, add solution B and solution C dropwise to dispersion A, heat to 40-50° C., stir for 2-3 h, centrifuge, wash the precipitate with anhydrous methanol 3 times, and finally soak in a 0.5-1.0% oleic acid methanol solution for 20-30 min, take out, and supercritically dry to obtain a multi-layer composite functional material. S3. The layered nanosilicate-loaded nitrogen-doped carbon nanofibers are annealed at 130-150° C., and then mixed with the multi-level composite functional material described in step S2. Polypropylene, an antioxidant, and calcium stearate are added and mixed evenly, wherein the antioxidant consists of equal weights of antioxidant 1010 and antioxidant 168. The mixture is then added to an extruder for melt extrusion and granulation. The feeding section temperature is controlled at 160-170° C. and the melt extrusion temperature is controlled at 180-200° C. to obtain a functional plastic fiber masterbatch material.

3. The method for preparing the functional plastic fiber masterbatch material according to claim 2, characterized in that: In step S1, the added amounts of Pluronic F127 and carboxylated carbon nanotubes are 150.0-200.0 mg and 10.0-15.0 mg, respectively.

4. The method for preparing the functional plastic fiber masterbatch material according to claim 3, characterized in that: In step S2, the amount of zinc nitrate hexahydrate added is 20.0-30.0 mg.

5. The method for preparing the functional plastic fiber masterbatch material according to claim 4, characterized in that: The method for preparing the layered nanosilicate-loaded nitrogen-doped carbon nanofibers specifically comprises the following steps: (1) Disperse the layered nanosilicate in 50 mL of deionized water and ultrasonically treat for 30-50 min to obtain a suspension for use. Then, dissolve 0.04-0.1 g of hexadecyltrimethylammonium bromide in 20 mL of 40-50 ° C water and stir until completely dissolved. Then, add the hexadecyltrimethylammonium bromide solution dropwise to the suspension over 20-30 min while stirring. Stir at 60-70 ° C for 24 h, centrifuge at a centrifugal speed of 12000-16000 rpm for 10-15 min, and wash the precipitate alternately with deionized water and ethanol solution three times, dry, and grind to obtain modified layered nanosilicate. (2) Dispersing the modified layered nanosilicate described in step (1) in a mixed solvent of 10 mL of N, N-dimethylformamide and acetone, wherein the volume ratio of N, N-dimethylformamide to acetone is 7:3, stirring continuously for 1-2 hours, then adding 0.1-0.2 g of urea and 0.1-0.2 g of melamine, stirring for 10-20 minutes, then adding polymethyl methacrylate, and finally adding 0.6-1.0 g of polyacrylonitrile, stirring at 40-45 ° C for 8-12 hours to obtain a spinning precursor solution; (3) The spinning precursor solution described in step (2) was filtered through a 0.45 μm filter membrane and then transferred to a 10 mL syringe. The syringe was equipped with a No. 25 stainless steel needle. The syringe and the pump were connected by a syringe pump. The flow rate was set to 0.8-1.0 mL / h, the voltage was 12-18 kV, and the distance was 12-15 cm. The collected spun fibers were placed in a muffle furnace, first heated to 130-150 ° C at a rate of 2 ° C / min and kept warm for 30 min, then oxidized in an air atmosphere at 240-250 ° C for 70-80 min. The stabilized fibers were then placed in a tubular furnace and heated to 700-800 ° C at a rate of 5 ° C / min. Ammonia was mixed into the nitrogen atmosphere, and the flow rate of ammonia accounted for 10-20% of the total gas flow. The fibers were carbonized for 70-90 min and cooled to obtain layered nanosilicate-loaded nitrogen-doped carbon nanofibers.

6. The method for preparing the functional plastic fiber masterbatch material according to claim 5, characterized in that: In step (1), the amount of layered nanosilicate added is 0.5-1.0 g.

7. The method for preparing the functional plastic fiber masterbatch material according to claim 6, characterized in that: In step (2), the amount of polymethyl methacrylate added is 0.1-0.5 g.

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