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CN-121975312-A - Preparation method for efficient and environment-friendly construction of conductive composite material isolation structure

CN121975312ACN 121975312 ACN121975312 ACN 121975312ACN-121975312-A

Abstract

The invention relates to the technical field of conductive composite materials and discloses a preparation method for constructing a conductive composite material isolation structure in a high-efficiency and environment-friendly manner, which comprises the following steps that S1, raw materials are prepared, polyamide 6 is selected as a composite material matrix, and polyamide 6 is thermoplastic engineering plastic; the method comprises the steps of S2, mixing by planetary ball milling, putting the selected polyamide 6 and carbon black into the planetary ball mill together according to the proportion of 92:8, S3, compression molding, putting the composite powder obtained after ball milling and mixing into a mold, and pre-realizing uniform coating of the carbon black on the surface of the polyamide 6 matrix particles by a two-step process combining dry planetary ball milling and compression molding, and then, carrying out hot pressing to enable the carbon black to be selectively enriched on the particle interface, thereby successfully constructing a conductive network with a three-dimensional honeycomb isolation structure, wherein the structure can form a high-efficiency conductive path under the extremely low addition level of only 8% of carbon black filling amount, and greatly reducing the filler consumption.

Inventors

  • ZONG YUMENG
  • YE CHANGHUAI

Assignees

  • 东华大学

Dates

Publication Date
20260505
Application Date
20260318

Claims (10)

  1. 1. The preparation method of the high-efficiency environment-friendly conductive composite material isolation structure is characterized by comprising the following steps of: S1, preparing raw materials, namely selecting polyamide 6 as a composite material matrix, wherein the polyamide 6 is thermoplastic engineering plastic, and the form of the polyamide 6 is one of granular or powdery; s2, planetary ball milling and mixing, namely placing the selected polyamide 6 and carbon black in a planetary ball mill together according to the proportion of 92:8, and carrying out ball milling and mixing treatment under the dry condition without any liquid solvent addition; And S3, compression molding, namely placing the composite powder obtained after ball milling and mixing in a mold, pressing the composite powder through a hot-press molding process, placing the mold filled with the composite powder on a working platform of a hot press, heating the mold to enable a polyamide 6 matrix to reach a molten state, heating the mold to a temperature higher than the melting point of the polyamide 6, and simultaneously applying pressure to the mold to enable the molten polyamide 6 matrix to flow and fill a mold cavity.
  2. 2. The preparation method of the efficient and environment-friendly conductive composite material isolation structure is characterized in that a polyamide 6 matrix is dried before planetary ball milling and mixing to remove absorbed moisture, the particle size of carbon black particles ranges from 30 nanometers to 50 nanometers and has a graphitized structure, and the polyamide 6 matrix provides mechanical properties, thermal properties and chemical resistance for the composite material.
  3. 3. The preparation method of the high-efficiency environment-friendly conductive composite material isolation structure is characterized in that planetary ball milling mixing treatment is carried out under the dry condition without any liquid solvent, the ball milling time is 1.5 hours, the ball-material ratio is the ratio of the mass of a grinding medium to the total mass of polyamide 6 and carbon black mixed powder, the grinding medium is zirconia balls or stainless steel balls, the diameter of the grinding medium is selected according to the initial particle size of polyamide 6 matrix particles, the revolution speed and the rotation speed of a ball mill are independently adjustable, the movement track and the acting force type of the grinding medium on materials are controlled by adjusting the speed ratio of revolution and rotation, and the mixture temperature of the polyamide 6 and the carbon black is controlled through the working system and intermittent operation of the ball mill in the whole mixing process.
  4. 4. The method for preparing the high-efficiency environment-friendly conductive composite isolation structure according to claim 1, wherein the hot-pressing temperature of the compression molding process is higher than the melting point of polyamide 6, polyamide 6 matrix particles in a molten state are pressed together by the hot-pressing pressure and carbon black particles at the interfaces of the polyamide 6 matrix particles are extruded and fixed, the dwell time is set according to the melt index, viscosity and carbon black content of the polyamide 6, a mold is removed from a hot press and cooled after compression molding is finished, a natural cooling or forced cooling mode is adopted in the cooling process, the demolding operation is carried out after the temperature of the mold is reduced below the thermal deformation temperature of the polyamide 6, and the adopted mold is designed according to the shape and size of a final product and can be directly molded into a conductive composite material component in a sheet shape, a block shape or other specific shapes.
  5. 5. The method for preparing the efficient and environment-friendly conductive composite isolation structure is characterized in that the mixing proportion of the polyamide 6 and the carbon black is determined according to the preset filling amount of the carbon black in the final composite material, the mass of the added carbon black accounts for 8% of the total mass of the polyamide 6 and the carbon black, and when the filling amount of the carbon black is 8%, the honeycomb three-dimensional conductive path is constructed through ball milling for 1.5 hours and compression molding.
  6. 6. The method for preparing the high-efficiency environment-friendly conductive composite isolation structure, which is characterized in that a three-dimensional honeycomb-shaped conductive path isolation structure is built in the composite material, wherein carbon black is continuously distributed along the interfaces of polyamide 6 matrix particles, the three-dimensional honeycomb-shaped conductive path isolation structure is formed by the following steps of ball milling and mixing, carbon black is attached to the surfaces of the polyamide 6 particles to form a core-shell structure, the polyamide 6 particles are heated and melted and deformed and fused under pressure in a compression molding step, carbon black attached to the surfaces of the particles is extruded and concentrated in interface areas among the particles, the carbon black in the interface areas is connected with each other along with the mutual fusion of the particles, a three-dimensional honeycomb-shaped conductive network covering the whole material is formed, the isolation structure is provided with a microstructure of a pure polyamide 6 phase, the carbon black is limited in the interface areas of the polyamide 6 matrix particles, the internal areas of the polyamide 6 particles are non-conductive, the three-dimensional honeycomb-shaped conductive path isolation structure is isotropic in the material, and the characteristic size of the isolation structure is regulated and controlled by selecting initial polyamide 6 particles with different particle sizes and adjusting carbon black content.
  7. 7. The method for preparing the efficient and environment-friendly conductive composite isolation structure is characterized in that the CB/PA6 conductive composite material is characterized in that the three-dimensional honeycomb conductive path isolation structure in the CB/PA6 conductive composite material endows the composite material with electromagnetic wave absorption performance when the carbon black filling amount is 8%, the minimum reflection loss value reaches 26.9dB, the corresponding matching thickness is 2.1 mm, the effective absorption bandwidth reaches 5.4GHz, and the construction quality of the three-dimensional honeycomb conductive path isolation structure is indirectly characterized by testing the volume conductivity or the surface conductivity of the composite material.
  8. 8. The preparation method of the high-efficiency environment-friendly conductive composite material isolation structure is characterized in that energy in a planetary ball milling mixing process is mainly used for overcoming friction force among materials and realizing collision of particles, energy in a compression molding process is mainly used for heating and pressurizing, and the preparation method is a two-step process for separating mixing and molding processes, namely, microstructure design of materials is realized through planetary ball milling, and macroscopic shape fixation of the materials is realized through compression molding.
  9. 9. The preparation method of the efficient and environment-friendly conductive composite material isolation structure is characterized in that the planetary ball milling mixing step is used for realizing controllable adjustment of the coating state of carbon black on the surface of the polyamide 6 by adjusting the rotating speed, the ball milling time, the ball material ratio and the size and the material of a grinding medium of a ball mill, so that the microscopic morphology and the conductive performance of the final composite material isolation structure are adjusted.
  10. 10. The method for preparing the high-efficiency environment-friendly conductive composite isolation structure is characterized in that the compression molding step is used for controlling the molten state of the polyamide 6 matrix, the migration behavior of carbon black and the fixing effect of the final isolation structure by adjusting the hot-pressing temperature, the hot-pressing pressure, the pressure maintaining time and the cooling rate, and the hot-pressing temperature, the hot-pressing pressure and the pressure maintaining time are set according to the melt index, the viscosity and the carbon black content of the polyamide 6.

Description

Preparation method for efficient and environment-friendly construction of conductive composite material isolation structure Technical Field The invention relates to the technical field of conductive composite materials, in particular to a preparation method for constructing a conductive composite material isolation structure in an efficient and environment-friendly manner. Background The traditional preparation method of the conductive composite material mainly adopts melt blending or solution blending technology, but the traditional preparation method of the conductive composite material usually has the defects of high addition amount of conductive filler, uneven dispersion, complex technology or environmental problems caused by using an organic solvent, and the like, for example, the melt blending technology is simple, the high shearing force is easy to destroy the filler structure, the filler is easy to randomly distribute in the matrix, an ideal isolation structure is difficult to form, the mechanical property of the material can be influenced and the cost can be increased due to the fact that the conductive percolation threshold can be reached due to the fact that the filler is generally required to be higher, and the solution blending can improve the dispersibility, but the method involves the use and recovery of a large amount of solvent and does not meet the development requirements of green environmental protection. Therefore, we propose a preparation method for constructing the conductive composite isolation structure in an efficient and environment-friendly way. Disclosure of Invention The invention aims to provide a preparation method for constructing a conductive composite material isolation structure in an efficient and environment-friendly manner, so as to solve the problems in the background technology. In order to achieve the above purpose, the invention provides the following technical scheme that the method comprises the following steps: S1, preparing raw materials, namely selecting polyamide 6 as a composite material matrix, wherein the polyamide 6 is thermoplastic engineering plastic, has one of granular or powdery shape and the characteristic of being capable of melt flow at the hot-pressing temperature, and selects carbon black as a conductive filler, wherein the carbon black is conductive carbon black, and the grain diameter of the particles is 30-50 nanometers and has a graphitized structure; S2, planetary ball milling and mixing, namely placing the selected polyamide 6 and carbon black in a planetary ball mill together according to the proportion of 92:8, performing ball milling and mixing treatment under the dry condition without adding any liquid solvent, wherein the revolution speed and the rotation speed of the ball mill are independently adjustable, and uniformly dispersing and physically adsorbing and mechanically embedding carbon black particles on the surfaces of polyamide 6 matrix particles by utilizing the mechanical force effects of impact, shearing, friction and the like generated by the movement of the grinding medium in a ball milling tank through adjusting the ball milling time, the ball material ratio and the size and the material of the grinding medium, so as to form composite powder with a core-shell structure, wherein the polyamide 6 particles are cores, the carbon black layer is shells, and the thickness and the uniformity of the carbon black shell layer are determined by the technological parameters of ball milling and mixing and the addition amount of the carbon black; And S3, compression molding, namely placing the composite powder obtained after ball milling and mixing in a mold, pressing the composite powder by a hot-press molding process, placing the mold filled with the composite powder on a working platform of a hot press, heating the mold to enable a polyamide 6 matrix to reach a molten state, enabling the heating temperature to be higher than the melting point of the polyamide 6, simultaneously applying pressure to the mold to enable the molten polyamide 6 matrix to flow and fill a mold cavity, under the combined action of heat and pressure, enabling polyamide 6 matrix particles to melt and fuse with each other, enabling a carbon black layer attached to the surfaces of the particles to crack and rearrange along with deformation of the particles, enabling carbon black fragments to be extruded and enriched in interface areas between the particles under the action of pressure, enabling carbon black in the interface areas to be connected with each other along with the mutual fusion of the particles, and finally constructing a three-dimensional honeycomb conductive path isolation structure formed by continuously distributing carbon black along the interfaces of the polyamide 6 matrix particles in the composite material, wherein the structure has the microstructure characteristics that the carbon black is limited in the interface areas of the polyamide 6 mat