High-strength antistatic nylon 6 composite material and preparation method thereof

Abstract

The application discloses a high-strength antistatic nylon 6 composite material and a preparation method thereof, and belongs to the field of composite material processing. The high-strength antistatic nylon 6 composite material is made of the following raw materials in parts by weight: modified antistatic filler (BZ-ACB@Ag) 3-8 parts, and nylon 6 particles 92-97 parts. Carbon black (CB) is gradually modified by 4-aminobenzoyl, silver nanoparticles and benzoxazine groups. After the acylation reaction, active sites are formed on the surface of the carbon black particles, then silver is loaded on the surface through a reaction, and finally the interaction between the carbon black and the polymer is adjusted through benzoxazine modification to improve the dispersibility of the carbon black in the matrix. BZ-ACB@Ag obtains a more extensive and complete conductive network in the nylon 6 matrix. A high-strength antistatic nylon 6 composite material is prepared by adopting the methods of melt blending, extrusion granulation and injection molding, and the high-strength antistatic nylon 6 composite material has good mechanical properties and thermal stability while maintaining excellent antistatic properties, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of composite materials processing, and particularly relates to a high-strength antistatic nylon 6 composite material and a preparation method thereof. BACKGROUND

[0002] With the continuous progress of technology, there is an increasing demand for new conductive materials for thinner, lighter and more portable displays. Conductive materials in the range of electrical conductivity, as well as materials with electrical conductivity, can be applied to electrostatic discharge products and electromagnetic interference products. With the continuous integration and accelerated development of optical fibers and information technology, various wearable device industries have developed materials with excellent electrical conductivity and the ability to transmit electrical signals.

[0003] Conductive polymer composites are prepared by filling conductive fillers into polymers according to a specified processing method and can stably provide electrical conductivity. Conductive polymer composites are used in electronics, energy and chemical engineering due to their wide electrical conductivity and ease of processing. The electrical conductivity of conductive polymer composites is highly dependent on the properties of the polymer and the type, loading level, geometry and dispersibility of the conductive filler. The three commonly used conductive fillers are carbon, metal and metal oxide, among which carbon is most commonly used due to its light weight, non-oxidation and ease of forming a conductive network; carbon-based fillers include carbon black, carbon fiber, graphite, carbon nanotube and graphene.

[0004] High loading levels of fillers can have certain adverse effects on the composite material, such as high viscosity, low processing performance and low mechanical performance. They often have poor physical properties. Therefore, it is necessary to develop polymer-based composites with high tensile strength and high electrical conductivity by adjusting the interaction between the conductive filler and the polymer.

[0005] The present application modifies carbon black in multiple ways, gradually modifying carbon black with 4-aminobenzoyl, silver nanoparticles and benzoxazine groups. After the acylation reaction of carbon black particles, active sites are formed on the surface, and the amino functional groups present on the surface improve the compatibility of carbon black with the nylon 6 matrix. Then, silver is loaded on the surface through a reaction, and silver, as a metal conductor, forms a synergistic conductive effect with carbon black, enabling the modified antistatic filler to form a conductive network inside the composite material. Finally, after modification with benzoxazine, the interaction between carbon black and the polymer is adjusted to improve its dispersibility in the matrix, enabling the modified antistatic filler to be distributed in the composite material at a lower percolation threshold, greatly improving the electrical conductivity of the composite material while ensuring mechanical performance. The present application uses nylon 6 as the matrix, and combines melt compounding with BZ-ACB@Ag to form an antistatic polymer composite material. The synergistic effect of the antistatic filler and the strong interaction between the filler and the matrix can further improve the mechanical properties and antistatic properties of the composite material. SUMMARY

[0006] The application aims to provide a high-strength antistatic nylon 6 composite material and a preparation method thereof, which have good antistatic effect and mechanical properties.

[0007] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0008] A high-strength antistatic nylon 6 composite material, wherein the raw materials used are as follows in terms of weight fraction: modified antistatic filler (BZ-ACB@Ag) 3-8 parts, and nylon 6 particles 92-97 parts.

[0009] The preparation of the modified antistatic filler includes the following steps:

[0010] (1) 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide are weighed and added to a four-necked reactor flask, and stirred under a high-torque mechanical disperser, and the reaction mixture is heated to 50 DEG C and 100 DEG C for 1.5 h respectively, so that the carbon black is fully dispersed in the mixture and the agglomeration phenomenon is reduced. Then, the temperature of the mixture is increased to 120 DEG C, and the stirring is continued for 48 h. As the reaction proceeds, the viscosity of the mixture system gradually increases. After the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for several times, and the sample is collected by filtration. At the same time, the sample is extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample is freeze-dried in a freeze dryer at low pressure, and the final black powder is collected, that is, p-aminobenzoic acid modified carbon black (ACB) is obtained;

[0011] (2) 10 g of the ACB prepared in step (1) is quickly dispersed in a silver nitrate (AgNO3) ethanol solution (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) is slowly added dropwise, so that Ag ions are attached to the surface of the ACB. Finally, the ACB is repeatedly washed with deionized water, and freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain ACB@Ag;

[0012] (3) 5 g of the ACB@Ag prepared in step (2) is added to 500 mL of 1,4-dioxane, and ultrasonically treated for 1 h. Then, 3 g of phenol and 3 g of paraformaldehyde are slowly added, and the mixture is stirred at 35 DEG C under reflux for 48 h. The obtained powder-like product is collected by suction filtration, and extracted with water by Soxhlet extraction for 24 h to completely remove the residual reaction medium and unreacted monomers. Finally, the product is freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain benzoxazine modified silver-loaded carbon black BZ-ACB@Ag.

[0013] The preparation of the high-strength antistatic nylon 6 composite material includes the following steps:

[0014] (1) The modified antistatic filler and nylon 6 particles are mixed uniformly, the mixture is dried at 80 DEG C for 24 h, and then extruded and granulated through a double-screw extruder;

[0015] (2) The mixed particles prepared in step (1) are injection molded in an injection molding machine to obtain a high-strength antistatic nylon 6 composite sample.

[0016] Further, the temperature of each zone in the extrusion granulation is 215 DEG C / 220 DEG C / 225 DEG C / 225 DEG C / 230 DEG C / 230 DEG C / 235 DEG C, and the rotation speed of the screw is 30 r / min; the injection molding temperature is 230 DEG C, the injection molding pressure is 60 MPa, the injection molding time is 5 s, and the cooling time is 8 s, and finally a high-strength antistatic nylon 6 composite is obtained.

[0017] The beneficial effects of the present application are that:

[0018] (1) The present application improves the dispersibility of the antistatic filler in the matrix by acylation of carbon black, and the compatibility between the antistatic filler and the resin matrix is improved, which improves the mechanical properties of the composite on the one hand, and the amino functional groups on the surface provide active sites for subsequent reactions on the other hand.

[0019] (2) In the present application, silver particles are loaded on carbon black as a carrier through a chemical reaction, and silver exhibits the largest electrical conductivity and thermal conductivity among all metals. Silver nanoparticles have a high surface area and excellent structural, electronic, and thermal properties. Therefore, the electrical conductivity can be improved by attaching silver nanoparticles. Two kinds of antistatic fillers with good electrical conductivity are connected together through chemical bonds, which can play a synergistic conductive role, and the combination of the two particles provides a long-distance conductive conduction channel inside the material. After further benzoxazine modification, the interaction between the modified carbon black and the polymer is enhanced, thereby further improving its dispersibility in the matrix, thereby forming a phase with a large amount of antistatic filler. Thus, a conductive network is formed at a low percolation threshold, i.e. the requirements of antistatic polymer materials can be met by a reduced filling amount.

[0020] (3) In the present application, after further benzoxazine modification, the interaction between the modified carbon black and the polymer is enhanced, thereby further improving its dispersibility in the matrix, thereby forming a phase with a large amount of antistatic filler. Thus, a conductive network is formed at a low percolation threshold, i.e. the requirements of antistatic polymer materials can be met by a reduced filling amount. At the same time, due to the interfacial interaction between the benzoxazine modified carbon black and the nylon 6 resin, the prepared antistatic nylon 6 composite also has high strength and excellent mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1Fourier infrared spectrum of the modified antistatic filler prepared in the present application.

[0022] Figure 2 Scanning electron micrograph of carbon black.

[0023] Figure 3 Scanning electron micrograph of ACB@Ag prepared in the present application.

[0024] Figure 4 Scanning electron micrograph of BZ-ACB@Ag prepared in the present application.

[0025] Figure 5 Scanning electron micrograph of antistatic nylon 6 composite prepared in Example 1 of the present application.

[0026] Figure 6 Scanning electron micrograph of antistatic nylon 6 composite prepared in Example 3 of the present application.

[0027] Figure 7 Scanning electron micrograph of antistatic nylon 6 composite prepared in Comparative Example 4 of the present application. DETAILED DESCRIPTION

[0028] In order to make the content of the present application more convenient to understand, the technical solutions of the present application will be further described below in combination with specific embodiments, but the present application is not limited thereto.

[0029] The preparation of a modified antistatic filler comprises the following steps:

[0030] (1) 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide were weighed respectively and added into a four-necked reactor flask, and stirred under a high-torque mechanical disperser, and the reaction mixture was heated to 50°C and 100°C respectively for 1.5 h, so that the carbon black was fully dispersed in the mixture and the agglomeration phenomenon was reduced. Then, the temperature of the mixture was increased to 120°C, and the stirring was continued for 48 h. As the reaction proceeded, the viscosity of the mixture system gradually increased. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for several times, and the sample was collected by filtration. At the same time, the sample was extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample was freeze-dried in a freeze dryer at low pressure, and the final black powder was collected, i.e. p-aminobenzoic acid modified carbon black (ACB) was obtained;

[0031] (2) 10 g of the ACB prepared in step (1) was quickly dispersed in a silver nitrate (AgNO3) ethanol solution (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) was slowly added dropwise to allow Ag ions to adhere to the surface of the ACB. Finally, the ACB@Ag was repeatedly washed with deionized water and freeze-dried under reduced pressure (0.05 mmHg) for 48 h;

[0032] (3) 5 g of the ACB@Ag prepared in step (2) was added to 500 mL of 1,4-dioxane and ultrasonicated for 1 h. Then, 3 g of phenol and 3 g of paraformaldehyde were slowly added, and the mixture was refluxed at 35°C with magnetic stirring for 48 h. The resulting powdered product was collected by suction filtration, Soxhlet extracted with water for 24 h to completely remove the residual reaction medium and unreacted monomers, and finally freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain the benzoxazine-modified silver-loaded carbon black BZ-ACB@Ag.

[0033] Figure 1 The Fourier infrared spectrum of the modified antistatic filler prepared in the present application is shown in the figure, in which 1384 cm -1 and 827 cm -1 correspond to the C-N stretching vibration peak and N-H out-of-plane bending vibration of ACB@Ag, respectively, indicating that the amidation modification is successful and provides a reactive site for CB. 2427 cm -1 is the characteristic absorption peak of Ag, indicating that Ag and ACB react with each other to form ACB@Ag. Further, a new peak type appears at 1178 cm -1 , which corresponds to the benzoxazine ring, 1554 cm -1 is the bending vibration peak of primary amine, which indicates that the benzoxazine-modified silver-loaded carbon black BZ-ACB@Ag has been successfully prepared.

[0034] Figure 2 The scanning electron micrograph of carbon black is shown in the figure. It can be seen that CB has obvious spherical and chain-like structures, with high height and surface area and porosity

[0035] Figure 3 The scanning electron micrograph of the ACB@Ag prepared in the present application is shown in the figure. It can be seen that Ag is loaded on CB to form a sheet-like structure.

[0036] Figure 4 The scanning electron micrograph of the BZ-ACB@Ag prepared in the present application is shown in the figure. It can be seen that after modification by benzoxazine, the surface of BZ-ACB@Ag becomes rough, and there are many organic modifiers on the surface.

[0037] Example 1

[0038] 1) 3 parts by weight of BZ-ACB@Ag and 97 parts by weight of nylon 6 particles were melt blended, extruded and granulated in a twin-screw extruder, and the temperature of each zone in the extrusion granulation was 215℃ / 220℃ / 225℃ / 225℃ / 230℃ / 230℃ / 235℃, and the rotation speed of the screw was 30 r / min;

[0039] 2) The mixed particles were injection molded by an injection molding machine, the injection molding temperature was 230℃, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, and finally an antistatic nylon 6 composite material was obtained.

[0040] The preparation steps of BZ-ACB@Ag are as follows:

[0041] (1) 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide were weighed into a four-necked reactor flask, and stirred under a high-torque mechanical disperser, and the reaction mixture was heated to 50℃ and 100℃ respectively for 1.5 h, so that the carbon black was fully dispersed in the mixture and the agglomeration phenomenon was reduced. Then, the temperature of the mixture was increased to 120℃, and the stirring was continued for 48 h. As the reaction proceeded, the viscosity of the mixture system gradually increased. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for several times, and the sample was collected by filtration. At the same time, the sample was extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample was freeze-dried in a freeze dryer at low pressure, and the final black powder was collected, which was p-aminobenzoic acid modified carbon black (ACB);

[0042] (2) 10 g of ACB prepared in step (1) was quickly dispersed in an ethanol solution of silver nitrate (AgNO3) (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) was slowly added dropwise, so that Ag ions were attached to the surface of ACB. Finally, it was repeatedly washed with deionized water and freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain ACB@Ag;

[0043] (3) 5 g of ACB@Ag prepared in step (2) was added to 500 mL of 1,4-dioxane, and ultrasonicated for 1 h. Then 3 g of phenol and 3 g of paraformaldehyde were slowly added, and stirred at 35℃ by magnetic stirring for 48 h. The obtained powder product was collected by suction filtration, and water was extracted by Soxhlet extraction for 24 h to completely remove the residual reaction medium and unreacted monomers. Finally, it was freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain benzoxazine modified silver-loaded carbon black BZ-ACB@Ag.

[0044] Figure 5The scanning electron microscope image of the antistatic nylon 6 composite material prepared in Example 1 of the present application. It can be seen that the BZ-ACB@Ag is uniformly distributed in the nylon 6 matrix, but due to the small amount of addition, it fails to form a conductive network.

[0045] Example 2

[0046] 1) 5 parts by weight of BZ-ACB@Ag and 95 parts by weight of nylon 6 particles were melt blended, extruded and granulated in a twin-screw extruder, and the temperature of each zone in the extrusion granulation was 215°C / 220°C / 225°C / 225°C / 230°C / 230°C / 235°C, and the rotation speed of the screw was 30 r / min;

[0047] 2) The mixed particles were injection molded by an injection molding machine, the injection molding temperature was 230°C, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, and finally the antistatic nylon 6 composite material was obtained.

[0048] The preparation steps of BZ-ACB@Ag are as follows:

[0049] (1) 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide were weighed into a four-necked reactor flask, respectively, and stirred under a high-torque mechanical disperser, and the reaction mixture was heated to 50°C and 100°C, respectively, for 1.5 h, so that the carbon black was fully dispersed in the mixture and the agglomeration phenomenon was reduced. Then, the temperature of the mixture was increased to 120°C, and the stirring was continued for 48 h. As the reaction proceeded, the viscosity of the mixture system gradually increased. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for several times, and the sample was collected by filtration. At the same time, the sample was extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample was freeze-dried in a freeze dryer at low pressure, and the final black powder was collected, i.e. p-aminobenzoic acid modified carbon black (ACB) was obtained;

[0050] (2) 10 g of ACB prepared in step (1) was quickly dispersed in an ethanol solution of silver nitrate (AgNO3) (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) was slowly added dropwise, so that Ag ions were attached to the surface of ACB. Finally, it was repeatedly washed with deionized water and freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain ACB@Ag;

[0051] (3) 5 g of the ACB@Ag prepared in step (2) was added to 500 mL of 1,4-dioxane and ultrasonicated for 1 h. Then, 3 g of phenol and 3 g of paraformaldehyde were slowly added, and the mixture was refluxed at 35 °C with magnetic stirring for 48 h. The obtained powder product was collected by suction filtration, Soxhlet extracted with water for 24 h to completely remove the residual reaction medium and unreacted monomers, and finally freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain the benzoxazine-modified silver-loaded carbon black BZ-ACB@Ag.

[0052] Example 3

[0053] 1) 8 parts by weight of BZ-ACB@Ag and 92 parts by weight of nylon 6 particles were melt blended, extruded and pelletized in a twin-screw extruder, and the temperature of each zone in the extrusion and pelletization was 215 °C / 220 °C / 225 °C / 225 °C / 230 °C / 230 °C / 235 °C, and the rotation speed of the screw was 30 r / min;

[0054] 2) The mixed particles were injection molded by an injection molding machine, and the injection molding temperature was 230 °C, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, and finally an antistatic nylon 6 composite material was obtained.

[0055] The preparation steps of BZ-ACB@Ag are as follows:

[0056] (1) 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid, and 120 g of phosphorus pentoxide were weighed into a four-necked reactor flask, and stirred under a high-torque mechanical disperser. The reaction mixture was heated to 50 °C and 100 °C for 1.5 h, respectively, to fully disperse the carbon black in the mixture and reduce the agglomeration phenomenon. Then, the temperature of the mixture was increased to 120 °C, and the stirring was continued for 48 h. As the reaction proceeded, the viscosity of the mixture system gradually increased. After the reaction was completed, the obtained precipitate was washed with ethanol and deionized water for multiple times, and the sample was collected by filtration. Meanwhile, the sample was Soxhlet extracted with deionized water to remove the residual reaction substances, and then extracted with methanol to remove the unreacted p-aminobenzoic acid and possible impurities. Finally, the sample was freeze-dried in a freeze dryer under low pressure, and the final black powder was collected to obtain p-aminobenzoic acid-modified carbon black (ACB);

[0057] (2) 10 g of the ACB prepared in step (1) was quickly dispersed in an ethanol solution of silver nitrate (AgNO3) (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) was slowly added dropwise to make Ag ions adhere to the surface of the ACB. Finally, the sample was repeatedly washed with deionized water, and freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain ACB@Ag;

[0058] (3) 5 g of the ACB@Ag prepared in step (2) was added to 500 mL of 1,4-dioxane and ultrasonicated for 1 h. Then 3 g of phenol and 3 g of paraformaldehyde were slowly added, and the mixture was refluxed at 35 °C with magnetic stirring for 48 h. The obtained powder product was collected by suction filtration, and water was used to Soxhlet extract for 24 h to completely remove the residual reaction medium and unreacted monomers. Finally, the product was freeze-dried under reduced pressure (0.05 mmHg) for 48 h to obtain the benzoxazine-modified silver-loaded carbon black BZ-ACB@Ag.

[0059] Figure 6 The scanning electron microscope image of the antistatic nylon 6 composite material prepared in Example 3 of the present application. After further benzoxazine modification, the interaction between the modified carbon black and the polymer is enhanced, thereby further improving the dispersibility of the modified carbon black in the matrix, thereby forming a phase with a large amount of antistatic filler. While maintaining the excellent antistatic effect of the composite material, it also has good mechanical properties.

[0060] Comparative Example 1

[0061] Pure nylon 6 sample

[0062] 1) The nylon 6 particles were melt blended and extruded into granules in a twin-screw extruder, and the temperature of each zone in the extrusion granulation was 215 °C / 220 °C / 225 °C / 225 °C / 230 °C / 230 °C / 235 °C, and the screw speed was 30 r / min.

[0063] 2) The mixed particles were injection molded by an injection molding machine, and the injection molding temperature was 230 °C, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, and finally the pure nylon 6 sample was obtained.

[0064] Comparative Example 2

[0065] 1) 3 parts by weight of CB and 97 parts by weight of nylon 6 particles were melt blended and extruded into granules in a twin-screw extruder, and the temperature of each zone in the extrusion granulation was 215 °C / 220 °C / 225 °C / 225 °C / 230 °C / 230 °C / 235 °C, and the screw speed was 30 r / min.

[0066] 2) The mixed particles were injection molded by an injection molding machine, and the injection molding temperature was 230 °C, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, and finally the antistatic nylon 6 composite material was obtained.

[0067] Comparative Example 3

[0068] 1) 5 parts by weight of CB and 95 parts by weight of nylon 6 particles were melt blended, extruded and granulated in a twin-screw extruder, the temperature of each zone in the extrusion granulation was 215℃ / 220℃ / 225℃ / 225℃ / 230℃ / 230℃ / 235℃, and the rotation speed of the screw was 30 r / min;

[0069] 2) The mixed particles were injection molded by an injection molding machine, the injection molding temperature was 230℃, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, finally an antistatic nylon 6 composite material was obtained.

[0070] Comparative Example 4

[0071] 1) 8 parts by weight of CB and 92 parts by weight of nylon 6 particles were melt blended, extruded and granulated in a twin-screw extruder, the temperature of each zone in the extrusion granulation was 215℃ / 220℃ / 225℃ / 225℃ / 230℃ / 230℃ / 235℃, and the rotation speed of the screw was 30 r / min;

[0072] 2) The mixed particles were injection molded by an injection molding machine, the injection molding temperature was 230℃, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, finally an antistatic nylon 6 composite material was obtained.

[0073] Figure 7 The scanning electron microscope image of the antistatic nylon 6 composite material prepared in Comparative Example 4 of the application. It can be seen that the excess CB will form agglomeration in the composite material, thereby affecting the conductivity efficiency and reducing the mechanical properties of the composite material.

[0074] Comparative Example 5

[0075] 1) 8 parts by weight of ACB and 92 parts by weight of nylon 6 particles were melt blended, extruded and granulated in a twin-screw extruder, the temperature of each zone in the extrusion granulation was 215℃ / 220℃ / 225℃ / 225℃ / 230℃ / 230℃ / 235℃, and the rotation speed of the screw was 30 r / min;

[0076] 2) The mixed particles were injection molded by an injection molding machine, the injection molding temperature was 230℃, the injection molding pressure was 60 MPa, the injection molding time was 5 s, and the cooling time was 8 s, finally an antistatic nylon 6 composite material was obtained.

[0077] The preparation steps of ACB are as follows:

[0078] Take 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide into a four-necked reactor flask, stir under a high-torque mechanical disperser, heat the reaction mixture to 50°C and 100°C respectively for 1.5 h, so that the carbon black is fully dispersed in the mixture and the agglomeration phenomenon is reduced. Then, increase the temperature of the mixture to 120°C and continue stirring for 48 h. As the reaction proceeds, the viscosity of the mixture system gradually increases. After the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for several times, and the sample is collected by filtration. At the same time, the sample is extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample is freeze-dried in a freeze dryer at low pressure, and the final black powder is collected to obtain p-aminobenzoic acid modified carbon black (ACB);

[0079] Comparative Example 6

[0080] 1) 8 parts by weight of ACB@Ag and 92 parts by weight of nylon 6 particles are melt blended, extruded and granulated in a twin-screw extruder, and the temperature of each zone in the extrusion granulation is 215°C / 220°C / 225°C / 225°C / 230°C / 230°C / 235°C, and the rotation speed of the screw is 30 r / min;

[0081] 2) The mixed particles are injection molded by an injection molding machine, and the injection molding temperature is 230°C, the injection molding pressure is 60 MPa, the injection molding time is 5 s, and the cooling time is 8 s, and finally an antistatic nylon 6 composite material is obtained.

[0082] The preparation steps of ACB@Ag are as follows:

[0083] (1) Take 10 g of p-aminobenzoic acid, 10 g of carbon black (CB), 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide into a four-necked reactor flask, stir under a high-torque mechanical disperser, heat the reaction mixture to 50°C and 100°C respectively for 1.5 h, so that the carbon black is fully dispersed in the mixture and the agglomeration phenomenon is reduced. Then, increase the temperature of the mixture to 120°C and continue stirring for 48 h. As the reaction proceeds, the viscosity of the mixture system gradually increases. After the reaction is completed, the obtained precipitate is washed with ethanol and deionized water for several times, and the sample is collected by filtration. At the same time, the sample is extracted with deionized water by Soxhlet extraction to remove residual reaction substances, and then extracted with methanol to remove unreacted p-aminobenzoic acid and possible impurities. Finally, the sample is freeze-dried in a freeze dryer at low pressure, and the final black powder is collected to obtain p-aminobenzoic acid modified carbon black (ACB);

[0084] (2) 10 g of the ACB prepared in step (1) was quickly dispersed in a silver nitrate (AgNO3) ethanol solution (0.05 mM). Then, a mixed solution of sodium borohydride (NaBH4) and ethanol (0.05 mM) was slowly added dropwise to allow Ag ions to adhere to the surface of the ACB. Finally, repeated washing with deionized water and freeze-drying under reduced pressure (0.05 mmHg) for 48 h yielded ACB@Ag.

[0085] The samples obtained in the examples and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0086]

[0087] Table 1 shows that with the addition of the modified antistatic filler (BZ-ACB@Ag), the tensile strength of the composite material also changes, and the filler acts as a reinforcing and toughening material to increase the tensile strength of the material. At the same time, the volume resistance of the composite material also decreases with the increase of BZ-ACB@Ag, and when 8 parts by weight is added, the volume resistance of the composite material decreases by seven orders of magnitude compared with pure nylon 6, achieving a very good antistatic effect. When unmodified carbon black is added, the antistatic effect and mechanical properties of the composite material also increase, but they are not as good as those of BZ-ACB@Ag, and when CB reaches 8 parts by weight, the mechanical properties of the composite material decrease, which is due to the general compatibility of CB with the composite material. With the increase of the filler, the filler gradually accumulates in the composite material, thereby causing stress concentration and reducing the tensile strength of the composite material. Under the same filling amount, the tensile strength and antistatic effect of the composite material added with BZ-ACB@Ag are better than those of the composite material added with ACB and ACB@Ag. This is because the interaction between BZ-ACB@Ag and the polymer is enhanced, thereby further improving the dispersibility of BZ-ACB@Ag in the matrix, thereby forming a phase with a large amount of antistatic filler. A conductive network can be formed at a low percolation threshold, that is, the requirements of the antistatic polymer material can be met by a reduced filling amount. At the same time, due to the interfacial interaction between the benzoxazine modified carbon black and the nylon 6 resin, the prepared antistatic nylon 6 composite material also has high strength and excellent mechanical properties. In summary, when 8 parts by weight of the antistatic filler BZ-ACB@Ag is added, a nylon 6 composite material with good mechanical properties and excellent antistatic properties can be prepared.

[0088] The above only describes the preferred embodiments of the present application, and any equivalent changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.

Claims

1. A high-strength, antistatic nylon 6 composite, characterized by: Raw materials by weight parts: modified antistatic filler 3-8 parts, nylon 6 particles 92-97 parts; the modified antistatic filler is benzoxazine modified silver loaded carbon black; The preparation of the modified antistatic filler comprises the following steps: (1) 10 g of p-aminobenzoic acid, 10 g of carbon black, 400 g of polyphosphoric acid and 120 g of phosphorus pentoxide are mixed, stirred at 50℃ for 1.5 h, stirred at 100℃ for 1.5 h, and stirred at 120℃ for 48 h. The obtained precipitate is washed with ethanol and deionized water, filtered, extracted with deionized water and methanol in turn, and freeze-dried to obtain p-aminobenzoic acid modified carbon black; (2) The p-aminobenzoic acid modified carbon black is quickly dispersed in an ethanol solution of silver nitrate, a mixed solution of sodium borohydride and ethanol is slowly added dropwise, washed repeatedly with deionized water, and freeze-dried for 48 h to obtain ACB@Ag; (3) 5 g of ACB@Ag is added to 500 mL of 1,4-dioxane, ultrasonicated for 1 h, 3 g of phenol and 3 g of polyformaldehyde are slowly added, magnetically stirred at 35℃ for reflux for 48 h, filtered, extracted with water for 24 h, and freeze-dried for 48 h to obtain benzoxazine modified silver loaded carbon black BZ-ACB@Ag.

2. A process for preparing the high-strength, antistatic nylon 6 composite of claim 1, characterized by: Comprising the following steps: (1) The modified antistatic filler and nylon 6 particles are mixed uniformly, dried at 80℃ for 24 h, and extruded and granulated; (2) The mixed particles prepared in step (1) are injection molded to obtain the high-strength antistatic nylon 6 composite material.

3. The method of claim 2, wherein: The temperature of each zone in the extrusion granulation is 215℃ / 220℃ / 225℃ / 225℃ / 230℃ / 230℃ / 235℃, and the screw rotation speed is 30 r / min.

4. The method of claim 2, wherein: The injection molding temperature is 230℃, the pressure is 60 MPa, the time is 5 s, and the cooling time is 8 s.

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