A conductive nylon composite material and a method for preparing the same

Abstract

The application provides a conductive nylon composite material and a preparation method thereof, and belongs to the technical field of polymer composite materials.The conductive nylon composite material takes a nylon matrix resin as a main body, introduces a hybrid conductive core containing conductive carbon black, gas phase growth carbon fiber, tannic acid, polyaniline and phytate interface fixation structure, and is matched with maleic anhydride grafted POE, an interface locking agent, an antioxidant and an anti-hydrolysis agent;in the preparation process, a polyphenol-coated carbonaceous dispersion system is first formed, then the hybrid conductive core is obtained through in-situ polyaniline reaction and phytate interface fixation, and the conductive master batch and secondary extrusion injection molding are used;the scheme is beneficial to the synergistic effect of the conductive framework, the polyaniline bridging structure and the interface fixation structure, improves the continuity of the conductive path under the condition of low filling and the interface stability of the hybrid conductive core and the nylon matrix, and simultaneously considers the processing adaptability and the structure maintenance under the condition of humidity and heat.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, and relates to a conductive nylon composite material and its preparation method. Background Technology

[0002] Nylon materials possess good wear resistance, oil resistance, and injection molding adaptability, making them widely used in electronic and electrical products, automotive parts, structural components, and functional injection molded products. Because ordinary nylon materials have high electrical resistance, when used in components requiring static dissipation or conductivity, conductive fillers such as conductive carbon black, carbon fibers, carbon nanotubes, graphene, or metal powders are typically introduced to create conductive pathways within the nylon matrix.

[0003] Existing conductive nylon materials often reduce material resistance by increasing the amount of conductive filler, compounding conductive fillers with different morphologies, or improving the dispersion state of the filler. While these methods can improve the initial conductivity to some extent, the conductive path usually depends on the random contact and physical overlap between the fillers. When the amount of conductive filler is low, the filler particles or fibers are easily isolated or semi-isolated, resulting in discontinuous conductive paths and large fluctuations in material resistance. When the amount of filler is further increased, it can easily cause filler agglomeration, increased melt viscosity, and decreased processing stability. Furthermore, the contact state between the fillers may still be affected by processing shearing and molding conditions.

[0004] Furthermore, the nylon matrix possesses a crystalline structure and strong polarity. During melt processing and cooling crystallization, the conductive filler is affected by matrix flow, shear dispersion, and the formation of crystalline / amorphous regions. If a stable interfacial interaction is lacking between the conductive filler and the nylon matrix, the contact points formed between the conductive fillers are prone to loosening, migration, or changes in contact resistance during subsequent thermal cycling or humid environments, leading to inconsistencies between the initial conductivity and the conductivity retention after service. Therefore, for conductive nylon composites, simply increasing the amount of conductive filler or simply compounding different conductive fillers is insufficient to reliably solve the problem of continuity of conductive pathways and retention of conductive networks under low filler conditions. How to enable the conductive filler to form a more continuous conductive pathway in the nylon matrix at lower conductive component addition levels, and how to improve the retention of this conductive pathway after thermal cycling and humid environments, remains a technical problem that needs further resolution for this type of material. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a conductive nylon composite material and its preparation method. The conductive nylon composite material is based on a nylon matrix resin, incorporating a hybrid conductive core containing conductive carbon black, vapor-grown carbon fibers, tannic acid, polyaniline, and a phytate interface fixing structure, along with maleic anhydride-grafted POE, an interface locking agent, an antioxidant, and an anti-hydrolysis agent. During preparation, a polyphenol-coated carbonaceous dispersion system is first formed, followed by in-situ reaction of polyaniline and phytate interface fixing to obtain the hybrid conductive core, which is then formed through conductive masterbatch and secondary extrusion injection molding. This approach facilitates the synergistic effect of the conductive skeleton, the polyaniline bridging structure, and the interface fixing structure, improving the continuity of the conductive pathway under low-filling conditions and the interfacial stability between the hybrid conductive core and the nylon matrix, while also considering processing adaptability and structural retention under humid and hot conditions.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a conductive nylon composite material, the method comprising: S1: Add conductive carbon black and vapor-grown carbon fiber to a mixed solution, and disperse by ultrasonication to obtain a carbonaceous dispersion. Add tannic acid to the carbonaceous dispersion, stir and react under a nitrogen atmosphere, and after centrifugation, redisperse the wet carbonaceous material in a mixed solvent to obtain a polyphenol-coated carbonaceous dispersion. S2: Add aniline to the polyphenol-coated carbonaceous dispersion, stir evenly, and then add phytic acid to adjust the pH of the system; then add ammonium persulfate solution dropwise, react, then add metal salt solution, adjust the pH with ammonia water, stir the reaction, wash the product with deionized water and ethanol, vacuum dry and grind to obtain the hybrid conductive core; S3: Vacuum-dry a portion of the nylon matrix resin to obtain pretreated nylon matrix resin, and vacuum-dry the hybrid conductive core to obtain pretreated hybrid conductive core; premix the pretreated nylon matrix resin, the pretreated hybrid conductive core, and antioxidant B, and granulate them in a twin-screw extruder to obtain conductive masterbatch. S4: The remaining nylon matrix resin, conductive masterbatch, maleic anhydride-grafted POE, interface locking agent, antioxidant A and anti-hydrolysis agent are mixed and fed into a twin-screw extruder for extrusion granulation, followed by injection molding to obtain a conductive nylon composite material.

[0007] As a preferred technical solution of the present invention, in step S1, the mass ratio of the conductive carbon black to the vapor-grown carbon fiber is (1.2-3.0):1, for example, it can be 1.2:1, 1.38:1, 1.56:1, 1.74:1, 1.92:1, 2.1:1, 2.28:1, 2.46:1, 2.64:1, 2.82:1 or 3.0:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0008] In some alternative embodiments, the volume ratio of ethanol to water in the mixed solution is 1:(1-3), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8 or 1:3, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0009] In some alternative embodiments, the power of the ultrasound is 100-200W, for example, it can be 100W, 110W, 120W, 130W, 140W, 150W, 160W, 170W, 180W, 190W or 200W, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0010] In some optional embodiments, the ultrasonic dispersion time is 20-40 min, for example, it can be 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0011] In some optional embodiments, the ratio of the total mass of the conductive carbon black and the vapor-grown carbon fiber to the volume of the mixed solution is 1 g:(50-100) mL, for example, it can be 1 g:50 mL, 1 g:55 mL, 1 g:60 mL, 1 g:65 mL, 1 g:70 mL, 1 g:75 mL, 1 g:80 mL, 1 g:85 mL, 1 g:90 mL, 1 g:95 mL or 1 g:100 mL, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0012] In some optional embodiments, the mass ratio of the tannic acid to the total mass of the conductive carbon black and the vapor-grown carbon fiber is (3-10):100, for example, it can be 3:100, 3.7:100, 4.4:100, 5.1:100, 5.8:100, 6.5:100, 7.2:100, 7.9:100, 8.6:100, 9.3:100 or 10:100, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0013] In some alternative embodiments, the temperature of the stirring reaction is 25-45°C, for example, 25°C, 27°C, 29°C, 31°C, 33°C, 35°C, 37°C, 39°C, 41°C, 43°C or 45°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0014] In some optional embodiments, the stirring reaction time is 2-5 hours, for example, 2 hours, 2.3 hours, 2.6 hours, 2.9 hours, 3.2 hours, 3.5 hours, 3.8 hours, 4.1 hours, 4.4 hours, 4.7 hours or 5 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0015] In some optional embodiments, the centrifugation speed is 2000-5000 rpm, for example, it can be 2000 rpm, 2300 rpm, 2600 rpm, 2900 rpm, 3200 rpm, 3500 rpm, 3800 rpm, 4100 rpm, 4400 rpm, 4700 rpm or 5000 rpm, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0016] In some optional embodiments, the centrifugation time is 5-15 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0017] In some optional embodiments, the mass fraction of the polyphenol-coated carbonaceous dispersion is 1-5 wt.%, for example, it can be 1 wt.%, 1.4 wt.%, 1.8 wt.%, 2.2 wt.%, 2.6 wt.%, 3 wt.%, 3.4 wt.%, 3.8 wt.%, 4.2 wt.%, 4.6 wt.%, or 5 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0018] As a preferred technical solution of the present invention, in step S2, the ratio of the mass of aniline to the total mass of conductive carbon black and vapor-grown carbon fiber is (5-20):100, for example, it can be 5:100, 6.5:100, 8:100, 9.5:100, 11:100, 12.5:100, 14:100, 15.5:100, 17:100, 18.5:100 or 20:100, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] In some optional embodiments, the temperature before adding phytic acid is 0-10°C, for example, it can be 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] In some alternative embodiments, the adjusted pH value is 2.0-2.8, for example, it can be 2.0, 2.08, 2.16, 2.24, 2.32, 2.4, 2.48, 2.56, 2.64, 2.72 or 2.8, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some alternative embodiments, the concentration of the ammonium persulfate solution is 0.5-1.5M, for example, it can be 0.5M, 0.6M, 0.7M, 0.8M, 0.9M, 1.0M, 1.1M, 1.2M, 1.3M, 1.4M or 1.5M, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0022] In some optional embodiments, the molar ratio of ammonium persulfate to aniline is (0.9-1.1):1, for example, it can be 0.9:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1, 1.0:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1 or 1.1:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0023] In some optional embodiments, the ammonium persulfate solution is added over a period of 1-3 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, or 3 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0024] In some optional embodiments, the reaction time after the addition of ammonium persulfate solution is 4-10 hours, for example, 4 hours, 4.6 hours, 5.2 hours, 5.8 hours, 6.4 hours, 7 hours, 7.6 hours, 8.2 hours, 8.8 hours, 9.4 hours, or 10 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0025] In some optional embodiments, the molar ratio of the metal ions derived from the metal salt to the phosphate groups in phytic acid is (0.1-0.3):1, for example, it can be 0.1:1, 0.12:1, 0.14:1, 0.16:1, 0.18:1, 0.2:1, 0.22:1, 0.24:1, 0.26:1, 0.28:1 or 0.3:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0026] In some alternative embodiments, the concentration of the ammonia water is 1-3M, for example, it can be 1M, 1.2M, 1.4M, 1.6M, 1.8M, 2M, 2.2M, 2.4M, 2.6M, 2.8M or 3M, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0027] In some alternative embodiments, the pH is adjusted to 4.0-4.5 using ammonia, for example, 4.0, 4.05, 4.1, 4.15, 4.2, 4.25, 4.3, 4.35, 4.4, 4.45 or 4.5, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0028] In some alternative embodiments, the temperature of the stirring reaction is 25-35°C, for example, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C or 35°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] In some optional embodiments, the stirring reaction time is 0.5-3 hours, for example, 0.5 hours, 0.75 hours, 1.0 hours, 1.25 hours, 1.5 hours, 1.75 hours, 2.0 hours, 2.25 hours, 2.5 hours, 2.75 hours or 3 hours, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] In some alternative embodiments, the pH of the washed filtrate is 5.0-6.5, for example, it can be 5.0, 5.15, 5.3, 5.45, 5.6, 5.75, 5.9, 6.05, 6.2, 6.35 or 6.5, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0031] The conductivity of the filtrate after washing is ≤500μS / cm.

[0032] In some optional embodiments, the vacuum drying temperature is 70-80°C, for example, it can be 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C or 80°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0033] In some optional embodiments, the vacuum drying time is 8-12 hours, for example, 8 hours, 8.4 hours, 8.8 hours, 9.2 hours, 9.6 hours, 10 hours, 10.4 hours, 10.8 hours, 11.2 hours, 11.6 hours or 12 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] As a preferred technical solution of the present invention, in step S3, the nylon matrix resin is PA6 or PA66; The drying temperature of the nylon matrix resin is 80-100℃, for example, it can be 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, 92℃, 94℃, 96℃, 98℃ or 100℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] In some optional embodiments, the drying time of the nylon matrix resin is 8-12 hours, for example, 8 hours, 8.4 hours, 8.8 hours, 9.2 hours, 9.6 hours, 10 hours, 10.4 hours, 10.8 hours, 11.2 hours, 11.6 hours or 12 hours, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0036] In some optional embodiments, the drying temperature of the hybrid conductive core is 70-90°C, for example, it can be 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 86°C, 88°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0037] In some optional embodiments, the drying time of the hybrid conductive core is 4-8 hours, for example, 4 hours, 4.4 hours, 4.8 hours, 5.2 hours, 5.6 hours, 6 hours, 6.4 hours, 6.8 hours, 7.2 hours, 7.6 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] The mass ratio of antioxidant 1010 to 168 in antioxidant B is 1:1.

[0039] In some optional embodiments, the mass ratio of the pretreated nylon matrix resin, the pretreated hybrid conductive core, and antioxidant B is (70-85):(15-30):(0.2-0.5), for example, it can be (70, 71.5, 73, 74.5, 76, 77.5, 79, 80.5, 82, 83.5 or 85):(15, 16.5, 18, 19.5, 21, 22.5, 24, 25.5, 27, 28.5 or 30):(0.2, 0.23, 0.26, 0.29, 0.32, 0.35, 0.38, 0.41, 0.44, 0.47 or 0.5), but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0040] In some optional embodiments, the vacuum degree during the extrusion process is -0.09 to -0.06 MPa, for example, it can be -0.09 MPa, -0.087 MPa, -0.084 MPa, -0.081 MPa, -0.078 MPa, -0.075 MPa, -0.072 MPa, -0.069 MPa, -0.066 MPa, -0.063 MPa or -0.06 MPa, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0041] In some optional embodiments, the temperature of the PA6 system is 220-250°C, for example, 220°C, 223°C, 226°C, 229°C, 232°C, 235°C, 238°C, 241°C, 244°C, 247°C or 250°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0042] In some optional embodiments, the temperature of the PA66 system is 255-265°C, for example, 255°C, 256°C, 257°C, 258°C, 259°C, 260°C, 261°C, 262°C, 263°C, 264°C or 265°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] In some alternative embodiments, the residence time of the material in the screw is 1-2 min, for example, it can be 1 min, 1.1 min, 1.2 min, 1.3 min, 1.4 min, 1.5 min, 1.6 min, 1.7 min, 1.8 min, 1.9 min or 2 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] As a preferred technical solution of the present invention, in step S4, the nylon matrix resin is PA6 or PA66.

[0045] The interface locking agent is one or more of the following: epoxy-functionalized styrene-acrylate copolymer (such as Joncryl ADR 4468), polyfunctional glycidyl methacrylate copolymer (such as Fine-Blend SAG-008), or triglycidyl isocyanate (TGIC).

[0046] In some optional embodiments, the mass ratio of antioxidant 1098 to antioxidant 168 in antioxidant A is 1:(1-2), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0047] In some optional embodiments, the temperature of the PA6 system is 220-250°C, for example, 220°C, 223°C, 226°C, 229°C, 232°C, 235°C, 238°C, 241°C, 244°C, 247°C or 250°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0048] In some optional embodiments, the temperature of the PA66 system is 260-275°C, for example, 260°C, 261.5°C, 263°C, 264.5°C, 266°C, 267.5°C, 269°C, 270.5°C, 272°C, 273.5°C or 275°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0049] In some alternative embodiments, the residence time of the material in the screw is 1-3 min, for example, it can be 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min, 2 min, 2.2 min, 2.4 min, 2.6 min, 2.8 min or 3 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0050] The anti-hydrolysis agent is Stabaxol P or Stabaxol P100.

[0051] In some optional embodiments, the mold temperature of the PA6 system is 70-90°C, for example, it can be 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 86°C, 88°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0052] In some optional embodiments, the mold temperature of the PA66 system is 80-110°C, for example, it can be 80°C, 83°C, 86°C, 89°C, 92°C, 95°C, 98°C, 101°C, 104°C, 107°C or 110°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0053] In some optional embodiments, the injection molding cycle is 25-65s, for example, it can be 25s, 29s, 33s, 37s, 41s, 45s, 49s, 53s, 57s, 61s or 65s, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0054] In some alternative embodiments, the cooling time is 15-40s, for example, it can be 15s, 17.5s, 20s, 22.5s, 25s, 27.5s, 30s, 32.5s, 35s, 37.5s or 40s, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0055] In some optional embodiments, the mass ratio of the total amount of the nylon matrix resin, the hybrid conductive core, the maleic anhydride-grafted POE, the interface locking agent, the antioxidant A, and the anti-hydrolysis agent in the final product is (80-90):(3-8):(3-8):(0.2-1):(0.3-0.5):(0.2-0.5), for example, it can be (80, 81, 82, 83, 84, 85, 86, 87, 88, 89, or 90):(3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, or 8):(3, 3.5, 4, 4.5, 5, 5.5, 6). 6.5, 7, 7.5 or 8): (0.2, 0.28, 0.36, 0.44, 0.52, 0.6, 0.68, 0.76, 0.84, 0.92 or 1): (0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48 or 0.5): (0.2, 0.23, 0.26, 0.29, 0.32, 0.35, 0.38, 0.41, 0.44, 0.47 or 0.5), but not limited to the listed values; other unlisted values ​​within this range also apply.

[0056] In a second aspect, the present invention provides a conductive nylon composite material, which is prepared according to the preparation method described in the first aspect.

[0057] In this invention, the hybrid conductive core is not a simple mixture of single conductive fillers, but rather a composite structure consisting of conductive carbon black, vapor-grown carbon fibers, tannic acid, polyaniline, and a phytate interface fixed structure formed by phytic acid and metal ions. The conductive carbon black has numerous particle contact points, and the vapor-grown carbon fibers have a specific aspect ratio. When combined, they form a carbonaceous conductive framework that integrates point-like contacts and fibrous overlaps, providing a foundation for subsequent conductive pathway construction.

[0058] Tannic acid can be deposited on the surface of conductive carbon black and vapor-grown carbon fibers through π-π interactions, hydrogen bonding, and adsorption, giving the carbonaceous conductive framework a polyphenolic structure. This polyphenolic structure helps improve the dispersion of carbonaceous fillers during liquid-phase processing and provides an adhesion interface for in-situ polymerization of aniline, making it easier for polyaniline to deposit on the surface of carbonaceous fillers and reducing the tendency for free polyaniline particles to form individually.

[0059] In the presence of phytic acid, aniline undergoes oxidative polymerization via ammonium persulfate to form polyaniline. After polyaniline is deposited on the surface of carbonaceous fillers, it can form contact bridging or semi-bridging structures between some adjacent carbonaceous fillers, thereby reducing the interfacial contact resistance between adjacent conductive fillers. Thus, conductive carbon black and vapor-grown carbon fibers primarily serve as the conductive framework, while polyaniline mainly serves as the contact bridging and interfacial resistance modulator, forming a complementary relationship.

[0060] After phytic acid is incorporated into polyaniline doping, it forms a phytate interface with metal ions derived from zinc acetate or magnesium acetate to fix the structure. This treatment can reduce the adverse effects of free acidic components on the thermal processing stability of nylon to a certain extent, while retaining the phosphate groups, hydroxyl groups, and nitrogen-containing structures on the surface of the hybrid conductive core. These structures can form hydrogen bonds, acid-base interactions, coordination interactions, or other interfacial interactions with amide groups, terminal amino groups, or terminal carboxyl groups in the nylon matrix, which facilitates the formation of a more stable interfacial bond between the hybrid conductive core and the nylon matrix.

[0061] In the processing of composite materials, preparing conductive masterbatch first, followed by secondary dilution and extrusion, helps reduce local agglomeration and feeding fluctuations caused by direct powder addition, and also facilitates the uniform distribution of hybrid conductive cores in the nylon system. Maleic anhydride-grafted POE can improve the compatibility between the nylon matrix and other components in the composite system while enhancing the toughness of the material; the epoxy groups in the interface locking agent can react with or strongly interact with the active sites on the surface of the nylon end groups or hybrid conductive cores; antioxidants and anti-hydrolysis agents help reduce the risk of instability in the matrix or interface structure under hot processing and humid conditions.

[0062] During the cooling and crystallization stage, the nylon matrix forms crystalline and amorphous regions. Because the surface of the hybrid conductive core simultaneously possesses polyphenol, polyaniline, and phytate interface structures, its interfacial interaction with the crystalline and amorphous regions of nylon differs from that of untreated carbonaceous fillers. This difference facilitates the tendency of the hybrid conductive core to accumulate at crystalline boundaries or amorphous interface regions, making it easier to form continuous or semi-continuous conductive pathways between conductive carbon black, vapor-grown carbon fibers, and polyaniline. Therefore, a synergistic relationship is formed between the structural design of the hybrid conductive core, phytate interface fixation, interface locking agents, and masterbatch processing, which is beneficial for achieving a balance between conductive pathway construction, interfacial bonding, and processing stability even with relatively low amounts of hybrid conductive cores added.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a hybrid conductive core composed of conductive carbon black, vapor-grown carbon fiber, tannic acid, polyaniline, and phytate interface fixing structure, enabling dot-shaped conductive filler, fibrous conductive filler, and polyaniline bridging structure to jointly participate in the construction of conductive pathways. This is beneficial for improving the problem of isolated dispersion and discontinuous contact of conductive filler under low filling conditions.

[0064] This invention utilizes tannic acid coating, in-situ polyaniline formation, and phytate interface fixation to simultaneously imbue the surface of the hybrid conductive core with polyphenol, nitrogen-containing conductive, and phosphate interface structures. This enhances the interfacial bonding stability between the hybrid conductive core and the nylon matrix, rather than relying solely on the physical overlap between conductive fillers.

[0065] The phytate interface fixation structure in this invention can reduce the impact of free acidic components on the high-temperature processing stability of nylon while retaining the bridging effect of the polyaniline interface, which is beneficial to improving the adaptability of the polyaniline-containing conductive system in the melt processing of nylon.

[0066] This invention utilizes the interfacial interaction between the surface structure of the hybrid conductive nucleus and the cooling and crystallization process of nylon, making it easier for the hybrid conductive nucleus to accumulate at the boundaries of the crystal region or the amorphous interface region, which is beneficial for forming continuous or semi-continuous conductive pathways. Attached Figure Description

[0067] Figure 1 This is a physical image of the conductive nylon composite material prepared in Example 1 of the present invention. Detailed Implementation

[0068] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include any obvious substitutions and modifications made to the embodiments described herein.

[0069] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone further purification or processing.

[0070] In this invention, the conductive carbon black has a BET specific surface area of ​​800-1500 m². 2 / g, DBP oil absorption value is 300-520mL / 100g.

[0071] The average diameter of the vapor-grown carbon fiber is 100-200 nm, and the average length is 5-20 μm.

[0072] The nylon matrix resins PA6 and PA66, measured according to ISO 307 using a 0.5% (w / w) 96% sulfuric acid solution, have a viscosity of 130-180 cm⁻¹. 3 / g; among which, the DSC melting peak temperature of PA6 is 215-225℃, and the DSC melting peak temperature of PA66 is 250-265℃.

[0073] The maleic anhydride-grafted POE is a maleic anhydride-grafted polyolefin elastomer based on ethylene-octene copolymer, with a maleic anhydride grafting rate of 0.5-1.2 wt.%.

[0074] Example 1 This embodiment provides a conductive nylon composite material and its preparation method, the preparation method specifically including the following steps: S1: Conductive carbon black and vapor-grown carbon fibers were added to a mixed solution at a mass ratio of 2.5:1, wherein the volume ratio of ethanol to water in the mixed solution was 1:2.5. The mixture was ultrasonically dispersed at 150W for 35 min to obtain a carbonaceous dispersion, wherein the ratio of the total mass of conductive carbon black and vapor-grown carbon fibers to the volume of the mixed solution was 1 g:80 mL. Tannic acid was added to the carbonaceous dispersion, wherein the mass ratio of tannic acid to the total mass of conductive carbon black and vapor-grown carbon fibers was 8:100. The mixture was stirred at 40℃ under a nitrogen atmosphere for 4 h. After centrifugation at 4000 rpm for 12 min, the wet carbonaceous material was redispersed in the mixed solvent to obtain a polyphenol-coated carbonaceous dispersion with a mass fraction of 4 wt.%. S2: Aniline was added to the polyphenol-coated carbon dispersion, wherein the mass ratio of aniline to the total mass of conductive carbon black and vapor-grown carbon fibers was 15:100. After stirring evenly, phytic acid was added at 8°C to adjust the pH of the system to 2.5. Subsequently, a 1.2M ammonium persulfate solution was added dropwise, wherein the molar ratio of ammonium persulfate to aniline was 1.0:1, and the ammonium persulfate solution was added dropwise over 2.5 hours. The reaction was carried out for 8 hours. Then, a zinc acetate solution was added, wherein the molar ratio of metal ions derived from the metal salt to phosphate groups in phytic acid was 0.25:1. The pH was adjusted to 4.2 using 3M ammonia water, and the reaction was stirred at 30°C for 2.5 hours. The product was washed with deionized water and ethanol until the pH of the filtrate was 6.0 and the conductivity was ≤500μS / cm. The product was then vacuum dried at 75°C for 11 hours and ground to obtain the hybrid conductive core. S3: A portion of nylon matrix resin PA6 (24 parts by mass) was vacuum dried at 90℃ for 10h to obtain pretreated nylon matrix resin, and a hybrid conductive core (6 parts by mass) was vacuum dried at 80℃ for 6h to obtain pretreated hybrid conductive core; the pretreated nylon matrix resin, the pretreated hybrid conductive core, and antioxidant B (antioxidant 1010 and 168 are compounded at a mass ratio of 1:1) were premixed at a mass ratio of 80:20:0.4 and fed into a twin-screw extruder for granulation; during the extrusion process, vacuum exhaust was turned on, the vacuum degree was -0.08MPa, the system temperature was controlled at 240℃, and the residence time of the material in the screw was 1.5min to obtain conductive masterbatch; S4: The remaining nylon matrix resin PA6 (61 parts by weight), conductive masterbatch, maleic anhydride-grafted POE, interface locking agent (Joncryl ADR 4468), antioxidant A (antioxidant 1098 and antioxidant 168 compounded at a mass ratio of 1:1.5), and anti-hydrolysis agent Stabaxol P were mixed and fed into a twin-screw extruder for granulation. The system temperature was controlled at 230℃, and the material residence time in the screw was 2.5 min. Injection molding was then performed, with the mold temperature set at 80℃, the injection cycle controlled at 50 s, and the cooling time at 30 s, to obtain the following result: Figure 1 The conductive nylon composite material shown has a mass ratio of 85:6:7:0.8:0.4:0.4 for the total amount of nylon matrix resin PA6, the hybrid conductive core, maleic anhydride grafted POE, the interface locking agent, the antioxidant A, and the anti-hydrolysis agent.

[0075] Example 2 This embodiment provides a conductive nylon composite material and its preparation method, the preparation method specifically including the following steps: S1: Conductive carbon black and vapor-grown carbon fibers were added to a mixed solution at a mass ratio of 1.2:1, wherein the volume ratio of ethanol to water in the mixed solution was 1:1. The mixture was ultrasonically dispersed at 100W for 20 min to obtain a carbonaceous dispersion, wherein the ratio of the total mass of conductive carbon black and vapor-grown carbon fibers to the volume of the mixed solution was 1 g: 50 mL. Tannic acid was added to the carbonaceous dispersion, wherein the mass ratio of tannic acid to the total mass of conductive carbon black and vapor-grown carbon fibers was 3:100. The mixture was stirred and reacted at 25°C under a nitrogen atmosphere for 2 h. After centrifugation at 2000 rpm for 5 min, the wet carbonaceous material was redispersed in the mixed solvent to obtain a polyphenol-coated carbonaceous dispersion with a mass fraction of 1 wt.%. S2: Aniline was added to the polyphenol-coated carbon dispersion, wherein the mass ratio of aniline to the total mass of conductive carbon black and vapor-grown carbon fibers was 5:100. After stirring evenly, phytic acid was added at 0°C to adjust the pH of the system to 2.0. Subsequently, a 0.5M ammonium persulfate solution was added dropwise, wherein the molar ratio of ammonium persulfate to aniline was 0.9:1, the ammonium persulfate solution was added dropwise over 1 hour, and the reaction was carried out for 4 hours. Then, a magnesium acetate solution was added, wherein the molar ratio of metal ions derived from the metal salt to phosphate groups in phytic acid was 0.1:1. The pH was adjusted to 4 using 1M ammonia water, and the reaction was stirred at 25°C for 0.5 hours. The product was washed with deionized water and ethanol until the pH of the filtrate was 5.0 and the conductivity was ≤500μS / cm. The product was then vacuum dried at 70°C for 8 hours and ground to obtain the hybrid conductive core. S3: A portion of nylon matrix resin PA66 (17 parts by mass) was vacuum dried at 80℃ for 8 hours to obtain pretreated nylon matrix resin. Hybrid conductive core (3 parts by mass) was vacuum dried at 70℃ for 4 hours to obtain pretreated hybrid conductive core. The pretreated nylon matrix resin, pretreated hybrid conductive core, and antioxidant B (antioxidant 1010 and 168 are compounded at a mass ratio of 1:1) were premixed at a mass ratio of 85:15:0.2 and fed into a twin-screw extruder for granulation. During the extrusion process, vacuum exhaust was turned on, the vacuum degree was -0.06MPa, the system temperature was controlled at 255℃, and the residence time of the material in the screw was 1 minute to obtain conductive masterbatch. S4: The remaining nylon matrix resin PA66 (73 parts by mass), conductive masterbatch, maleic anhydride-grafted POE, interface locking agent (Fine-Blend SAG-008), antioxidant A (antioxidant 1098 and antioxidant 168 are compounded in a mass ratio of 1:1) and anti-hydrolysis agent Stabaxol P100 are mixed and fed into a twin-screw extruder for granulation. The system temperature is controlled at 260℃, and the material residence time in the screw is 1 min. Then, injection molding is performed. The system mold temperature is set at 80℃, the injection cycle is controlled at 25s, and the cooling time is 15s to obtain a conductive nylon composite material. The mass ratio of the total amount of nylon matrix resin PA66, hybrid conductive core, maleic anhydride-grafted POE, interface locking agent, antioxidant A and anti-hydrolysis agent in the conductive nylon composite material is 90:3:3:0.2:0.3:0.2.

[0076] Example 3 This embodiment provides a conductive nylon composite material and its preparation method, the preparation method specifically including the following steps: S1: Conductive carbon black and vapor-grown carbon fibers were added to a mixed solution at a mass ratio of 1.8:1, wherein the volume ratio of ethanol to water in the mixed solution was 1:1.5. The mixture was ultrasonically dispersed at 200W for 25 min to obtain a carbonaceous dispersion, wherein the ratio of the total mass of conductive carbon black and vapor-grown carbon fibers to the volume of the mixed solution was 1 g: 60 mL. Tannic acid was added to the carbonaceous dispersion, wherein the mass ratio of tannic acid to the total mass of conductive carbon black and vapor-grown carbon fibers was 5:100. The mixture was stirred and reacted at 30℃ under a nitrogen atmosphere for 5 h. After centrifugation at 5000 rpm for 15 min, the wet carbonaceous material was redispersed in the mixed solvent to obtain a polyphenol-coated carbonaceous dispersion with a mass fraction of 2 wt.%. S2: Aniline was added to the polyphenol-coated carbon dispersion, wherein the mass ratio of aniline to the total mass of conductive carbon black and vapor-grown carbon fibers was 10:100. After stirring evenly, phytic acid was added at 5°C to adjust the pH of the system to 2.2. Subsequently, a 0.8M ammonium persulfate solution was added dropwise, wherein the molar ratio of ammonium persulfate to aniline was 1.1:1, and the ammonium persulfate solution was added dropwise over 1.5 hours. The reaction was carried out for 6 hours. Then, a zinc acetate solution was added, wherein the molar ratio of metal ions derived from the metal salt to phosphate groups in phytic acid was 0.15:1. The pH was adjusted to 4.5 using 2M ammonia water, and the reaction was stirred at 35°C for 1.5 hours. The product was washed with deionized water and ethanol until the pH of the filtrate was 6.5 and the conductivity was ≤500μS / cm. The product was then vacuum dried at 80°C for 9 hours and ground to obtain the hybrid conductive core. S3: A portion of nylon matrix resin PA66 (18.67 parts by mass) was vacuum dried at 100℃ for 12h to obtain pretreated nylon matrix resin. Hybrid conductive core (8 parts by mass) was vacuum dried at 90℃ for 8h to obtain pretreated hybrid conductive core. The pretreated nylon matrix resin, pretreated hybrid conductive core, and antioxidant B (antioxidant 1010 and 168 are compounded at a mass ratio of 1:1) were premixed at a mass ratio of 70:30:0.5 and fed into a twin-screw extruder for granulation. During the extrusion process, vacuum exhaust was turned on, the vacuum degree was -0.09MPa, the system temperature was controlled at 265℃, and the residence time of the material in the screw was 2min to obtain conductive masterbatch. S4: The remaining nylon matrix resin PA66 (61.33 parts by mass), conductive masterbatch, maleic anhydride-grafted POE, interface locking agent (triglycidyl isocyanurate), antioxidant A (antioxidant 1098 and antioxidant 168 compounded at a mass ratio of 1:1.8), and anti-hydrolysis agent Stabaxol P are mixed and fed into a twin-screw extruder for granulation. The system temperature is controlled at 275℃, and the material residence time in the screw is 2 minutes. Then, injection molding is performed. The system mold temperature is set at 110℃, the injection cycle is controlled at 40 seconds, and the cooling time is 20 seconds to obtain a conductive nylon composite material. The mass ratio of the total amount of nylon matrix resin PA66, the hybrid conductive core, maleic anhydride-grafted POE, the interface locking agent, antioxidant A, and the anti-hydrolysis agent in the conductive nylon composite material is 80:8:5:1:0.5:0.5.

[0077] Example 4 This embodiment provides a conductive nylon composite material and its preparation method, the preparation method specifically including the following steps: S1: Conductive carbon black and vapor-grown carbon fibers were added to a mixed solution at a mass ratio of 3.0:1, wherein the volume ratio of ethanol to water in the mixed solution was 1:3. The mixture was ultrasonically dispersed at 120W for 40 min to obtain a carbonaceous dispersion, wherein the ratio of the total mass of conductive carbon black and vapor-grown carbon fibers to the volume of the mixed solution was 1 g: 100 mL. Tannic acid was added to the carbonaceous dispersion, wherein the mass ratio of tannic acid to the total mass of conductive carbon black and vapor-grown carbon fibers was 10:100. The mixture was stirred at 45°C under a nitrogen atmosphere for 3 h. After centrifugation at 3000 rpm for 8 min, the wet carbonaceous material was redispersed in the mixed solvent to obtain a polyphenol-coated carbonaceous dispersion with a mass fraction of 5 wt.%. S2: Aniline was added to the polyphenol-coated carbon dispersion, wherein the mass ratio of aniline to the total mass of conductive carbon black and vapor-grown carbon fibers was 20:100. After stirring evenly, phytic acid was added at 10°C to adjust the pH of the system to 2.8. Subsequently, a 1.5M ammonium persulfate solution was added dropwise, wherein the molar ratio of ammonium persulfate to aniline was 1.05:1, and the ammonium persulfate solution was added dropwise over 3 hours. The reaction was carried out for 10 hours. Then, a zinc acetate solution was added, wherein the molar ratio of metal ions derived from the metal salt to phosphate groups in phytic acid was 0.3:1. The pH was adjusted to 4.4 using 2.5M ammonia water, and the reaction was stirred at 28°C for 3 hours. The product was washed with deionized water and ethanol until the pH of the filtrate was 5.5 and the conductivity was ≤500μS / cm. The product was then vacuum dried at 72°C for 12 hours and ground to obtain the hybrid conductive core. S3: A portion of nylon matrix resin PA6 (12 parts by mass) was vacuum dried at 85℃ for 11h to obtain pretreated nylon matrix resin, and a hybrid conductive core (4 parts by mass) was vacuum dried at 75℃ for 7h to obtain pretreated hybrid conductive core; the pretreated nylon matrix resin, the pretreated hybrid conductive core, and antioxidant B (antioxidant 1010 and 168 are compounded at a mass ratio of 1:1) were premixed at a mass ratio of 75:25:0.3 and fed into a twin-screw extruder for granulation; during the extrusion process, vacuum exhaust was turned on, the vacuum degree was -0.07MPa, the system temperature was controlled at 230℃, and the residence time of the material in the screw was 1.8min to obtain conductive masterbatch; S4: The remaining nylon matrix resin PA6 (76 parts by mass), conductive masterbatch, maleic anhydride grafted POE, interface locking agent (Fine-Blend SAG-008), antioxidant A (antioxidant 1098 and antioxidant 168 are compounded at a mass ratio of 1:2) and anti-hydrolysis agent Stabaxol P are mixed and fed into a twin-screw extruder for granulation. The system temperature is controlled at 240℃, and the material residence time in the screw is 3 minutes. Then, injection molding is performed. The system mold temperature is set at 75℃, the injection cycle is controlled at 65s, and the cooling time is 40s to obtain a conductive nylon composite material. The mass ratio of the total amount of nylon matrix resin PA6, hybrid conductive core, maleic anhydride grafted POE, interface locking agent, antioxidant A and anti-hydrolysis agent in the conductive nylon composite material is 88:4:8:0.5:0.35:0.3.

[0078] Comparative Example 1 This comparative example provides a conductive nylon composite material and its preparation method. The difference from Example 1 is that tannic acid is not added in S1, while the other operation steps and process parameters are exactly the same as in Example 1.

[0079] Comparative Example 2 This comparative example provides a conductive nylon composite material and its preparation method. The difference from Example 1 is that aniline and ammonium persulfate are not added in S2, and aniline oxidative polymerization is not performed. Other operation steps and process parameters are exactly the same as in Example 1.

[0080] Comparative Example 3 This comparative example provides a conductive nylon composite material and its preparation method. The difference from Example 1 is that zinc acetate solution is not added in S2, and the coordination fixation treatment of metal ions and phosphate groups in phytic acid is not performed. Other operation steps and process parameters are exactly the same as in Example 1.

[0081] Comparative Example 4 This comparative example provides a conductive nylon composite material and its preparation method. The difference from Example 1 is that no interface locking agent is added in S4, while the other operation steps and process parameters are exactly the same as in Example 1.

[0082] The performance of the conductive nylon composite materials of Examples 1-4 and Comparative Examples 1-4 was tested, and the specific process is as follows: Initial surface resistance test: The initial surface resistance of each sample was tested using a surface resistance tester.

[0083] Resistance change rate test after thermal cycling: The sample after the initial surface resistance test was placed in a thermal cycling chamber for thermal cycling treatment. The thermal cycling conditions were: low temperature stage -30℃ for 1 hour, high temperature stage 80℃ for 1 hour, heating and cooling rate of 5℃ / min, and 50 cycles. After the thermal cycling was completed, the sample was removed and placed in an environment of 23±2℃ and 50±5% relative humidity for 2 hours. Subsequently, the surface resistance was tested again under the same test conditions as the initial surface resistance test, and the resistance change rate was calculated.

[0084] Resistance change rate test after damp heat treatment: Another sample from the same batch that underwent the initial surface resistance test was placed in a constant temperature and humidity chamber and treated at 85℃ and 85%RH for 168 hours. After the damp heat treatment, the sample was removed, surface moisture was wiped off, and it was placed at 23±2℃ and 50±5% relative humidity for 2 hours. Subsequently, the surface resistance was tested again under the same conditions as the initial surface resistance test, and the resistance change rate was calculated.

[0085] The test results are shown in Table 1.

[0086] Table 1. Performance test results of conductive nylon composite materials in Examples 1-4 and Comparative Examples 1-4

[0087] As shown in Table 1, the test results of Example 1 and Comparative Example 1 show that without the addition of tannic acid, the carbon conductive skeleton lacks a polyphenol coating layer, reducing the interfacial interaction sites between the conductive carbon black and the surface of the vapor-grown carbon fiber. This leads to a decrease in the uniformity and adhesion stability of the subsequent polyaniline deposition on the carbon filler surface, resulting in reduced effective contact between adjacent conductive fillers and thus an increase in initial surface resistance. Due to the insufficient stability of the interface structure of the hybrid conductive core, the thermal expansion difference between the nylon matrix and the conductive filler is more likely to cause loosening of the contact points during thermal cycling, increasing the resistance change rate after thermal cycling. In a humid and hot environment, insufficient interfacial bonding and uneven distribution of polar components exacerbate the instability of the conductive pathway, increasing the resistance change rate after humid heat treatment.

[0088] As shown in Table 1, the test results of Example 1 and Comparative Example 2 show that without the addition of aniline and ammonium persulfate, no polyaniline bridging layer was formed. Although a carbonaceous conductive skeleton composed of conductive carbon black and vapor-grown carbon fibers still existed, the lack of polyaniline deposition layer, bridging layer, or semi-bridging structure between adjacent carbonaceous fillers increased the contact resistance between fillers, thus raising the initial surface resistance. Since the conductive path mainly relies on the direct physical contact between carbonaceous fillers, the contact points are more prone to change after being affected by the shrinkage and expansion of the matrix during thermal cycling, resulting in an increased resistance change rate after thermal cycling. During the humid heat treatment, the lack of polyaniline bridging between fillers made the conductive path more sensitive to changes in the interface state, thus also increasing the resistance change rate after humid heat treatment.

[0089] As shown in Table 1, the test results of Example 1 and Comparative Example 3 indicate that without the addition of zinc acetate solution, no phytate interface fixation structure was formed. Although polyaniline can form and participate in conductive bridging in the presence of phytic acid, there are many free acidic components and unfixed phytic acid structures in the system, resulting in insufficient stability of the interface structure on the surface of the hybrid conductive core. Therefore, the initial surface resistance increases. During the thermal cycling process, the lack of phytate fixation structure weakens the interface retention ability between the hybrid conductive core and the nylon matrix, making the contact state of the conductive path more prone to change, leading to an increase in the resistance change rate after thermal cycling. In a humid heat environment, free acidic components, hygroscopic effect, and insufficient interface fixation jointly affect the polyaniline doping state and filler contact state, resulting in a significant increase in the resistance change rate after humid heat treatment.

[0090] As shown in Table 1, the test results of Example 1 and Comparative Example 4 indicate that even without the addition of an interface locking agent, the hybrid conductive core still contains the interface fixing structure of conductive carbon black, vapor-grown carbon fiber, tannic acid, polyaniline, and phytate. Therefore, the initial conductive pathway can still be formed, and the initial surface resistance only shows a certain increase. However, due to the lack of an interface locking agent, the reaction or strong interfacial interaction between the hybrid conductive core and the nylon matrix is ​​weakened. During the thermal cycling process, the micro-interface loosening between the conductive filler and the matrix is ​​more likely to occur, resulting in an increased resistance change rate after thermal cycling. During the humid heat treatment process, insufficient interfacial bonding amplifies the effects of moisture absorption and heat on the conductive network, leading to an increased resistance change rate after humid heat treatment.

[0091] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A conductive nylon composite material, characterized in that, The conductive nylon composite material includes a nylon matrix resin, a hybrid conductive core, maleic anhydride-grafted POE, an interface locking agent, antioxidant A, and an anti-hydrolysis agent. In the conductive nylon composite material, the mass ratio of the total amount of nylon matrix resin, hybrid conductive core, maleic anhydride grafted POE, interface locking agent, antioxidant A and anti-hydrolysis agent is (80-90):(3-8):(3-8):(0.2-1):(0.3-0.5):(0.2-0.5); The hybrid conductive core includes conductive carbon black, vapor-grown carbon fiber, tannic acid, polyaniline, and a structure formed by phytic acid and metal ions. The mass ratio of the conductive carbon black to the vapor-grown carbon fiber is (1.2-3.0):1; The hybrid conductive core is dispersed in the nylon matrix resin.

2. The conductive nylon composite material according to claim 1, characterized in that, The nylon matrix resin is PA6 or PA66; the metal ions are derived from metal salts, and the metal salts are zinc acetate or magnesium acetate.

3. The conductive nylon composite material according to claim 1, characterized in that, The interface locking agent is selected from one or more of epoxy-functionalized styrene-acrylate copolymer, polyfunctional glycidyl methacrylate copolymer, or triglycidyl isocyanurate; the antioxidant A is obtained by compounding antioxidant 1098 and antioxidant 168 in a mass ratio of 1:(1-2); the anti-hydrolysis agent is Stabaxol P or Stabaxol P100.

4. A method for preparing a conductive nylon composite material as described in any one of claims 1-3, characterized in that, The preparation method includes: S1: Conductive carbon black and vapor-grown carbon fibers are added to a mixed solution and ultrasonically dispersed to obtain a carbonaceous dispersion; tannic acid is added to the carbonaceous dispersion, and after stirring, centrifugation and redispersion, a polyphenol-coated carbonaceous dispersion is obtained. S2; Add aniline to the polyphenol-coated carbonaceous dispersion, then add phytic acid to adjust the pH of the system, and then add ammonium persulfate solution dropwise to carry out the reaction; after the reaction, add metal salt solution to fix the phytate interface, and after washing, vacuum drying and grinding, obtain the hybrid conductive core; S3: After vacuum drying a portion of the nylon matrix resin and the hybrid conductive core, pretreated nylon matrix resin and pretreated hybrid conductive core are obtained. After premixing with antioxidant B, they are granulated by a twin-screw extruder to obtain conductive masterbatch. S4: The remaining nylon matrix resin, conductive masterbatch, maleic anhydride-grafted POE, interface locking agent, antioxidant A and anti-hydrolysis agent are mixed, granulated by a twin-screw extruder and injection molded to obtain the conductive nylon composite material.

5. The method for preparing a conductive nylon composite material according to claim 4, characterized in that, In S1, the volume ratio of ethanol to water in the mixed solution is 1:(1-3), the ratio of the total mass of conductive carbon black and vapor-grown carbon fibers to the volume of the mixed solution is 1g:(50-100)mL; the ratio of the mass of tannic acid to the total mass of conductive carbon black and vapor-grown carbon fibers is (3-10):100; the stirring is carried out under a nitrogen atmosphere at 25-45℃ for 2-5h; and the mass fraction of the polyphenol-coated carbonaceous dispersion is 1-5wt.%.

6. The method for preparing a conductive nylon composite material according to claim 4, characterized in that, In S2, the mass ratio of aniline to the total mass of conductive carbon black and vapor-grown carbon fiber is (5-20):100; after adding phytic acid, the pH of the system is adjusted to 2.0-2.8; the concentration of ammonium persulfate solution is 0.5-1.5M, the molar ratio of ammonium persulfate to aniline is (0.9-1.1):1, the dropping time of ammonium persulfate solution is 1-3h, and the reaction time is 4-10h.

7. The method for preparing a conductive nylon composite material according to claim 4, characterized in that, In S2, the molar ratio of metal ions derived from metal salts to phosphate groups in phytic acid is (0.1-0.3):1; the pH is adjusted to 4-4.5 using 1-3M ammonia water, and the reaction is stirred at 25-35℃ for 0.5-3h; the product is washed with deionized water and ethanol until the pH of the filtrate is 5.0-6.5 and the conductivity is ≤500μS / cm, and then vacuum dried at 70-80℃ for 8-12h.

8. The method for preparing a conductive nylon composite material according to claim 4, characterized in that, In S3, a portion of the nylon matrix resin is vacuum dried at 80-100℃ for 8-12 hours, and the hybrid conductive core is vacuum dried at 70-90℃ for 4-8 hours. The mass ratio of pretreated nylon matrix resin, pretreated hybrid conductive core, and antioxidant B is (70-85):(15-30):(0.2-0.5), wherein antioxidant B is a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1; during the twin-screw extrusion process in S3, vacuum exhaust is turned on, with a vacuum degree of -0.06 to -0.09 MPa, the temperature of PA6 system is 220-250℃, and the temperature of PA66 system is 255-265℃.

9. The method for preparing a conductive nylon composite material according to claim 4, characterized in that, In S4, the temperature range for PA6 system is 220-250℃, and for PA66 system it is 260-275℃. During injection molding, the mold temperature for PA6 system is 70-90℃, and for PA66 system it is 80-110℃.

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