Conductive plastic material and preparation method thereof

Abstract

The invention provides a conductive plastic material and a preparation method thereof. Relates to the technical field of conductive materials. The conductive plastic material is composed of a base material, a magnetoelectric synergistic composite filler and an interface reinforcing agent, the magnetoelectric synergistic composite filler and the interface reinforcing agent are uniformly mixed in the base material; wherein the matrix material is a thermoplastic polymer having a melt flow index greater than or equal to 20 g / 10 min and a melting point less than 180 DEG C. According to the invention, the conductive plastic material has good conductivity and elasticity.

Description

Technical Field

[0001] The present application relates to the technical field of conductive materials, and in particular to a conductive plastic material and a method for preparing the conductive plastic material. Background Art

[0002] Conductive plastic materials, as core components of flexible electronic devices and protective materials, must possess both high conductivity and excellent elasticity. Conventional conductive composites achieve conductivity by adding conductive fillers (such as metal particles and carbon nanotubes) to a polymer matrix (e.g., silicone rubber). However, their performance is limited by the percolation threshold value (PTV). Reducing the PTV has become a key challenge in resolving the trade-off between conductivity and elasticity.

[0003] In the related art, the PTV is reduced by inducing the filler to form an ordered structure, but there are problems such as complex process and poor directional controllability.

[0004] Therefore, there is an urgent need to develop a conductive plastic material with a simple preparation process, uniform filler arrangement, good conductivity and elasticity. Summary of the Invention

[0005] The present application provides a conductive plastic material and a method for preparing the conductive plastic material, so as to enable the conductive plastic material to achieve better conductivity and elasticity.

[0006] In a first aspect, the present application provides a conductive plastic material, which is composed of a matrix material, a magnetoelectric synergistic composite filler, and an interface enhancer; the magnetoelectric synergistic composite filler and the interface enhancer are uniformly mixed in the matrix material; wherein the matrix material is a thermoplastic polymer with a melt flow index greater than or equal to 20 g / 10 min and a melting point less than 180°C.

[0007] In one possible embodiment, the magnetoelectric synergistic composite filler is composed of magnetic core-shell particles and a conductive agent; wherein the core of the magnetic core-shell particles is Fe3O4, the surface of the core is covered with a SiO2 insulating layer, and the surface of the SiO2 insulating layer is covered with a conductive polypyrrole PPy shell layer.

[0008] In one possible embodiment, the particle size of the core is in the range of 50 nm to 100 nm, the thickness of the PPy shell is in the range of 10 nm to 20 nm, and the thickness of the SiO2 insulating layer is in the range of 5 nm to 10 nm.

[0009] In one possible implementation, the conductive agent is modified carbon nanotubes; wherein the diameter of the modified carbon nanotubes ranges from 10 nm to 20 nm, and the length of the modified carbon nanotubes ranges from 10 μm to 50 μm.

[0010] In a possible implementation manner, the interface enhancer is a silane coupling agent, and epoxy groups are added to the silane coupling agent; the added amount of the interface enhancer is 0.3 wt % to 0.8 wt %.

[0011] In a second aspect, the present application provides a method for preparing a conductive plastic material, for preparing the conductive plastic material according to the first aspect and any possible embodiment of the first aspect, the method comprising:

[0012] The core material is coated with a first coating material and a second coating material to obtain magnetic core-shell particles;

[0013] The magnetic core-shell particles are grafted with a conductive agent to obtain a magnetoelectric synergistic composite filler;

[0014] The magnetoelectric synergistic composite filler, interface enhancer and matrix material are melt-blended and subjected to a magnetic field to obtain a conductive plastic material.

[0015] In one possible embodiment, the core material is Fe3O4 nanoparticles, the first coating is ethyl orthosilicate, and the second coating is pyrrole. The core material is coated with the first coating and the second coating to obtain magnetic core-shell particles, including:

[0016] Dispersing the core material in ethanol, adding the first coating material, and reacting sufficiently to obtain a first coating mixed solution;

[0017] After drying the first coating mixed liquid, first coated particles are obtained;

[0018] Dispersing the first coated particles in an aqueous solution containing the second coated material, adding ammonium persulfate initiator, and reacting for 4 hours under uniform stirring to obtain a second coated mixed solution;

[0019] The precipitate obtained after centrifuging the second coating mixture is washed to obtain magnetic core-shell particles, wherein the centrifugation time is 5 minutes to 10 minutes;

[0020] In one possible embodiment, the interface enhancer is a silane coupling agent containing an epoxy group, and the mass ratio of the core material to the interface enhancer is 1:(1-4).

[0021] In one possible embodiment, the magnetic core-shell particles are grafted with a conductive agent to obtain a magnetoelectric synergistic composite filler, comprising:

[0022] The conductive agent is acidified with concentrated nitric acid to introduce carboxyl functional groups on the surface of the conductive agent to obtain a carboxyl-modified conductive agent;

[0023] The magnetic core-shell particles and the carboxyl-modified conductive agent are uniformly mixed in a mass ratio of 1:3 to obtain a first component;

[0024] 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was added to the first component as a catalyst, and a catalytic reaction was carried out at a temperature of 60° C. for 6 hours to obtain a magnetoelectric synergistic composite filler.

[0025] In one possible embodiment, the magnetoelectric synergistic composite filler, the interface enhancer and the matrix material are melt-blended and subjected to a magnetic field to obtain a conductive plastic material, including:

[0026] Melting and mixing the magnetoelectric synergistic composite filler and the matrix material to obtain a second component, wherein the magnetoelectric synergistic composite filler accounts for 0.1 wt% to 40 wt% of the second component;

[0027] adding an interface enhancer to the second component and placing the second component in a rotating magnetic field for magnetization to obtain a molten composite material, wherein the rotating magnetic field has an axial magnetic field strength ranging from 20 mT to 50 mT and a radial rotation frequency ranging from 2 Hz to 5 Hz;

[0028] The molten composite material is rapidly solidified through a liquid nitrogen cooling channel to lock the filler's directional arrangement structure and obtain a solidified composite material; the cooling rate of the liquid nitrogen cooling channel is greater than or equal to 50°C / s;

[0029] The internal defects of the cured composite material are eliminated by hot pressing to obtain a conductive plastic material. The hot pressing temperature is 150° C. and the pressure is 10 MPa.

[0030] The conductive plastic material and the method for preparing the conductive plastic material provided in this application enable synergistic effects between the matrix material, the magnetoelectric synergistic composite filler, and the interface enhancer through the design of the conductive plastic material components, thereby simplifying the preparation process of the conductive plastic material and making the conductive plastic material have excellent electrical conductivity, good magnetic properties, high stability, and easy processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0032] Figure 1 Schematic diagram of the process of preparing the conductive plastic material provided in the embodiment of the present application Figure 1 ;

[0033] Figure 2 Schematic diagram of the process of preparing the conductive plastic material provided in the embodiment of the present application Figure 2 .

[0034] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0036] In combination with the above scenarios, it can be seen that in the prior art, the method of reducing PTV by inducing the filler to form an ordered structure has the problems of complex process and poor directional controllability.

[0037] The conductive plastic material provided in the embodiments of the present application, through the design of the conductive plastic material components, enables synergistic interaction between the base material, the magnetoelectric synergistic composite filler, and the interface enhancer, thereby simplifying the preparation process of the conductive plastic material and making the conductive plastic material have excellent conductive properties, good magnetic properties, high stability, and easy processability.

[0038] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0039] One embodiment of the present application provides a conductive plastic material, which is composed of a base material, a magnetoelectric synergistic composite filler, and an interface enhancer; the magnetoelectric synergistic composite filler and the interface enhancer are uniformly mixed in the base material; wherein the base material is a thermoplastic polymer with a melt flow index greater than or equal to 20 g / 10 min and a melting point less than 180°C.

[0040] Conductive plastics are composite materials that combine electrical conductivity and plastic properties. The matrix material is the primary component of the conductive plastic material, supporting and bonding the magnetoelectric composite filler and interface enhancer. The matrix material is typically a thermoplastic polymer with good flowability and processability.

[0041] Alternatively, the plastic polymer may be polypropylene. Polypropylene has a melting point range of 160°C to 170°C. The melt flow index (MFI) is a measure of the flow properties of a polymer melt; a higher MFI value indicates better material flow. The MFI of polypropylene is typically greater than or equal to 20 g / 10 min, ensuring uniform dispersion of the composite filler within the matrix material.

[0042] Magnetoelectric synergistic composite fillers contain magnetic materials and conductive materials. The magnetic material in the magnetoelectric synergistic composite filler can respond to magnetic fields, while the conductive material is responsible for conducting current. Through the synergistic effect between the magnetic and conductive materials, the conductivity and magnetic properties of the magnetoelectric synergistic composite filler are enhanced.

[0043] An interface enhancer is an additive used to improve the bonding strength between interfaces of different materials. By using an interface enhancer, the compatibility between different components in a magnetoelectric synergistic composite filler can be improved, thereby enhancing the overall performance of the magnetoelectric synergistic composite filler.

[0044] Optionally, the magnetoelectric synergistic composite filler is composed of magnetic core-shell particles and a conductive agent; wherein the core of the magnetic core-shell particles is Fe3O4, the surface of the core is covered with a SiO2 insulating layer, and the surface of the SiO2 insulating layer is covered with a conductive polypyrrole (PPy) shell layer.

[0045] Magnetic core-shell particles are magnetic materials with a core-shell structure, consisting of a core and two coating layers. Fe₃O₄ exhibits excellent magnetic properties and chemical stability. Fe₃O₄ is an inverse spinel ferrite with soft magnetic properties that responds to external magnetic fields. When SiO₂ is used as a coating layer on the core, it insulates and protects the core, preventing direct contact with external conductive components, avoiding interference with magnetic signals, and protecting the core of the magnetic core-shell particle from the external chemical environment. PPy exhibits excellent electrical conductivity and chemical stability and can be formed into a thin film through chemical polymerization and coated on the surface of other materials. Polypyrrole is the outermost shell of the magnetic core-shell particle, imparting its electrical conductivity. Magnetic core-shell particles are Fe₃O₄@SiO₂@PPy particles with an Fe₃O₄ core, an insulating SiO₂ layer on the core surface, and a conductive polypyrrole (PPy) shell formed by in-situ oxidative polymerization on the SiO₂ insulating layer. The core-shell structure of the magnetic core-shell particle effectively isolates the core from the external environment. Through the synergistic effect of the Fe3O4 in the inner core of the magnetic core-shell particles and the outermost conductive PPy shell, the magnetic core-shell particles have the dual properties of magnetism and conductivity.

[0046] Conductive agents are additives that enhance the electrical conductivity of magnetoelectric composite fillers. They are composed of highly conductive materials. By grafting magnetic core-shell particles onto the conductive agent, the conductivity of the magnetoelectric composite filler can be enhanced. Optionally, the conductive agent is carbon nanotubes and / or modified carbon nanotubes.

[0047] Furthermore, the particle size of the core is in the range of 50nm-100nm, the thickness of the PPy shell is in the range of 10nm-20nm, and the thickness of the SiO2 insulating layer is in the range of 5nm-10nm.

[0048] Specifically, the particle size of the kernel can be 50nm-100nm, for example, 50nm, 60nm, 75nm, 100nm or a range consisting of any two thereof. At a scale of 50nm-100nm, the magnetism of Fe3O4 exhibits superparamagnetism. In the absence of an external magnetic field, the magnetic moments of the nanoparticles are randomly distributed, and under the action of an external magnetic field, the magnetic moments are rapidly aligned, allowing the magnetic core-shell particles to respond quickly in a magnetic field and not generate hysteresis losses in a field-free state. At the same time, the particle size of 50nm-100nm, while ensuring the magnetism of the magnetic core-shell particles, also takes into account the dispersibility and stability of the magnetic core-shell particles.

[0049] The thickness of the SiO2 insulating layer ranges from 5 nm to 10 nm, for example, 5 nm, 6 nm, 8 nm, 10 nm, or a combination of any two thereof. The 5 nm to 10 nm SiO2 insulating layer improves the interfacial compatibility between the core and the outer conductive layer, effectively isolates the magnetic properties of the core from the external conductive components, prevents interference with magnetic signals, and protects the core from the external chemical environment, thereby improving the overall performance of the magnetic core-shell particle.

[0050] The thickness of the PPy shell layer is in the range of 10 nm to 20 nm, for example, 10 nm, 13 nm, 16 nm, 20 nm, or a combination thereof. The magnetic properties of the PPy layer and the core work in synergy to achieve a magnetoelectric synergistic effect.

[0051] Optionally, the conductive agent is modified carbon nanotubes; wherein the diameter of the modified carbon nanotubes ranges from 10 nm to 20 nm, and the length of the modified carbon nanotubes ranges from 10 μm to 50 μm.

[0052] The modified carbon nanotubes used as the conductive agent have a diameter range of 10 nm to 20 nm and a length range of 10 μm to 50 μm. The modified carbon nanotubes used as the conductive agent have a diameter range of 10 nm to 20 nm, such as 10 nm, 13 nm, 16 nm, 20 nm, or a range consisting of any two thereof. The modified carbon nanotubes used as the conductive agent have a length range of 10 μm to 50 μm, such as 10 μm, 25 μm, 30 μm, 50 μm, or a range consisting of any two thereof.

[0053] When the conductive agent is modified carbon nanotubes, such as carboxylated carbon nanotubes (CNTs), Fe3O4@SiO2@PPy particles are chemically grafted onto the surface of the CNTs via amide bonds, forming a magnetoelectric synergistic composite filler with a "CNT-magnetic core-shell particle" heterostructure.

[0054] In addition, the interface enhancer is a silane coupling agent, and epoxy groups are added to the silane coupling agent; the addition amount of the interface enhancer is 0.3wt%-0.8wt%.

[0055] Silane coupling agents enhance the compatibility and bonding strength of conductive plastic materials by forming a chemical bond between the magnetoelectric composite filler and the matrix material. The interface enhancer is added at a dosage of 0.3-0.8 wt%. Epoxy groups are highly reactive and react with the functional groups in the magnetic core-shell particles, forming a strong chemical bond.

[0056] For example, when the interface enhancer is a silane coupling agent, the interface enhancer can be a silane coupling agent KH560 containing an epoxy group, through which the epoxy group in the silane coupling agent reacts with the carboxyl group on the surface of the CNT to enhance the interface bonding between the magnetoelectric synergistic composite filler and the matrix material.

[0057] Excellent conductive properties and interfacial compatibility are achieved by precisely controlling the size of modified carbon nanotubes and the composition of the silane coupling agent.

[0058] Figure 1 Schematic diagram of the process of preparing the conductive plastic material provided in the embodiment of the present application Figure 1 .like Figure 1 As shown, the method for preparing a conductive plastic material includes:

[0059] S101, using a first coating material and a second coating material to coat the core material to obtain magnetic core-shell particles.

[0060] The core material is the inner core of the magnetic core-shell particle. The core material is magnetic Fe₃O₄, which provides the magnetic properties of the magnetic core-shell particle. The first and second coatings are used to coat the core material. Magnetic core-shell particles are obtained by coating the core material with the first and second coatings.

[0061] Coating is the process of wrapping one material around the surface of another. This is typically achieved through chemical or physical methods. Alternatively, the coating process can be performed using any of the following methods: chemical vapor deposition, sol-gel, and others.

[0062] S102, grafting the magnetic core-shell particles with a conductive agent to obtain a magnetoelectric synergistic composite filler.

[0063] Grafting is the process of chemically attaching a conductive agent to the surface of a material, such as a magnetic core-shell particle. The resulting magnetoelectric synergistic composite filler combines the magnetic properties of the magnetic core-shell particles with the conductivity of the conductive agent, resulting in a magnetoelectric synergistic effect.

[0064] S103, melt-blending the magneto-electric synergistic composite filler, the interface enhancer and the matrix material, and obtaining a conductive plastic material under the action of a magnetic field.

[0065] The magnetoelectric synergistic composite filler, interface enhancer and matrix material are melted by heating and then evenly mixed under the action of a magnetic field to form a conductive plastic material with good conductive properties.

[0066] Under the action of the magnetic field, the magneto-electric synergistic composite filler can be oriented in the magnetic field to optimize the magnetic properties and conductive properties of the conductive plastic material.

[0067] The conductive plastic material preparation method provided in the embodiment of the present application has excellent conductive properties, good magnetic properties, high stability and easy processability through core-shell structure design, grafting treatment and magnetic field oriented arrangement.

[0068] Figure 2 Schematic diagram of the process of preparing the conductive plastic material provided in the embodiment of the present application Figure 2 .like Figure 2 As shown, this embodiment Figure 1 Based on the embodiment, a method for preparing the conductive plastic material is described in detail, and the method comprises:

[0069] In one possible embodiment, the core material is Fe3O4 nanoparticles, the first coating is ethyl orthosilicate, and the second coating is pyrrole. The above step S101 may further include:

[0070] S1011. Disperse the core material in ethanol, add the first coating material, and after sufficient reaction, obtain a first coating mixed solution.

[0071] The core material Fe3O4 nanoparticles are added to ethanol and stirred to uniformly disperse the core material in the ethanol to obtain a dispersed core material ethanol solution. Then, the first coating material ethyl orthosilicate is added to the dispersed core material ethanol solution. Under the reaction conditions corresponding to the method, the ethyl orthosilicate and the core material are coated to form a uniform coating layer, thereby obtaining a first coating mixed solution containing the core material coated with the first coating.

[0072] S1012, drying the first coating mixed liquid to obtain first coated particles.

[0073] The first coating mixture is placed in a drying apparatus, where the ethanol is removed by heating or reducing pressure to obtain first coated Fe3O4@SiO2 particles. Optionally, the drying apparatus can be a rotary evaporator or an oven. After drying, the surface of the resulting Fe3O4@SiO2 particles is uniformly coated with ethyl orthosilicate.

[0074] S1013, dispersing the first coated particles in an aqueous solution containing the second coated material, adding ammonium persulfate initiator, and reacting for 4 hours under uniform stirring to obtain a second coated mixed solution.

[0075] The first coated particles are added to an aqueous solution containing the second coated material and stirred to uniformly disperse them, yielding a dispersed aqueous solution. Ammonium persulfate initiator is added to the dispersed aqueous solution to initiate polymerization of the second coated material. The polymerization reaction is allowed to proceed for 4 hours under uniform stirring, allowing the second coated material to evenly coat the Fe3O4@SiO2 surface. Stirring ensures full contact between the first coated particles and the second coated material, increasing the reaction rate.

[0076] Optionally, the mass ratio of the first coated particles to ammonium persulfate is 1:(1-5).

[0077] S1014. Wash the precipitate obtained after centrifuging the second coating mixed solution to obtain magnetic core-shell particles. The centrifugation time is 5 minutes to 10 minutes.

[0078] The second coating mixture is placed in a centrifuge and centrifuged at an appropriate speed and time to separate the solid particles from the liquid, yielding a precipitate of solid particles. The precipitate is then washed multiple times with deionized water or another suitable solvent to remove any residual ammonium persulfate on the surface, yielding magnetic core-shell Fe3O4@SiO2@PPy particles.

[0079] In a possible implementation, the above step S102 may further include:

[0080] S1021. Acidify the conductive agent with concentrated nitric acid to introduce carboxyl functional groups on the surface of the conductive agent to obtain a carboxyl-modified conductive agent.

[0081] The conductive agent is immersed in concentrated nitric acid, whereby the surface of the conductive agent is oxidized by a chemical reaction, introducing carboxyl functional groups, and obtaining an aqueous solution containing the carboxyl-modified conductive agent. The carboxylated carbon nanotubes are removed from the aqueous solution containing the carboxyl-modified conductive agent and washed multiple times with deionized water to remove residual concentrated nitric acid, thereby obtaining the carboxyl-modified conductive agent.

[0082] Optionally, when the conductive agent is modified carbon nanotubes, the modified carbon nanotubes are immersed in concentrated nitric acid, and the surface of the modified carbon nanotubes is oxidized by a chemical reaction, thereby introducing carboxyl functional groups to obtain CNTs.

[0083] S1022. Evenly mix the magnetic core-shell particles and the carboxyl-modified conductive agent in a mass ratio of 1:3 to obtain a first component.

[0084] The magnetic core-shell particles and the carboxyl-modified conductive agent are weighed in a mass ratio of 1:3 and placed in a mixing device to uniformly mix the magnetic core-shell particles and the carboxyl-modified conductive agent to obtain a first component.

[0085] S1023. Add 1-ethyl-(3-dimethylaminopropyl)carbodiimide as a catalyst to the first component, carry out a catalytic reaction at a temperature of 60° C. for 6 hours to obtain a magnetoelectric synergistic composite filler.

[0086] 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was added as a catalyst to the first component and mixed to ensure uniform distribution of the catalyst throughout the first component, yielding the catalyst-added first component. The catalyst-added first component was then placed in a constant temperature environment at 60°C for a catalytic reaction, resulting in the grafting of the magnetic core-shell particles to the surface of the carboxyl-modified conductive agent via amide bonds. The catalytic reaction lasted for 6 hours, resulting in the resulting magnetoelectric synergistic composite filler.

[0087] In a possible implementation, the above step S103 may further include:

[0088] S1031. Melt-mix the magnetoelectric synergistic composite filler and the matrix material to obtain a second component, wherein the magnetoelectric synergistic composite filler accounts for 0.1 wt% to 40 wt% of the second component.

[0089] The matrix material is heated to a molten state, and the magnetoelectric synergistic composite filler is added to the molten matrix material, and the magnetoelectric synergistic composite filler and the matrix material are uniformly mixed by stirring to obtain a second component, wherein the second component is a molten mixture.

[0090] The proportion of the magnetoelectric synergistic composite filler in the second component is 0.1wt% to 40wt%. Exemplarily, the proportion of the magnetoelectric synergistic composite filler is 0.1wt%, 10wt%, 25wt%, 40wt% or any two thereof.

[0091] Optionally, the matrix material is polypropylene particles.

[0092] S1032. Add an interface enhancer to the second component and place it in a rotating magnetic field for magnetization to obtain a molten composite material. The rotating magnetic field has an axial magnetic field strength in the range of 20mT-50mT and a radial rotation frequency in the range of 2Hz-5Hz.

[0093] The interface enhancer is added to the second component and uniformly dispersed in the second component by stirring to obtain the second component with the interface enhancer added. The second component with the interface enhancer is placed in a rotating magnetic field for magnetization to obtain a molten composite material.

[0094] Under the action of a rotating magnetic field, the inner core Fe3O4 in the magnetic core-shell particles is affected by the magnetic field and oriented along the direction of the magnetic field, driving the magnetic core-shell particles and the conductive agent grafted to the magnetic core-shell particles to stretch along the direction of the magnetic field; at the same time, through the conductive bridge points provided by the outermost conductive PPy shell of the magnetic core-shell particles, a three-dimensional continuous conductive network is formed, so that the obtained molten composite material has good conductivity and elasticity.

[0095] The conductive agent in the molten composite material stretches along the magnetic field direction of the rotating magnetic field, and the dispersed conductive agent is connected through the conductive bridge points provided by the corresponding coating layer of the second coating material in the magneto-electric synergistic composite filler, forming a molten composite material with a three-dimensional continuous conductive network structure.

[0096] S1033. Rapidly solidify the molten composite material through a liquid nitrogen cooling channel to lock the directional arrangement structure of the filler and obtain a solidified composite material; the cooling rate of the liquid nitrogen cooling channel is greater than or equal to 50°C / s.

[0097] The molten composite material is passed through a liquid nitrogen cooling channel, where a cooling rate of 50°C / s or greater is used to rapidly reduce the material temperature and solidify the molten composite material. Rapidly cooling the molten composite material through the liquid nitrogen cooling channel locks in the oriented structure formed by the magnetoelectric synergistic composite filler in the magnetic field, preventing the molten composite material from becoming disorganized during the cooling process, resulting in a solidified composite material with a uniform distribution of the magnetoelectric synergistic composite filler.

[0098] S1034. Eliminate internal defects of the cured composite material by hot pressing to obtain a conductive plastic material. The hot pressing temperature is 150° C. and the pressure is 10 MPa.

[0099] The cured composite material is placed in a hot press and heated to 150°C while applying a pressure of 10 MPa for hot pressing. During the hot pressing process, the cured composite material reflows under the high temperature and pressure, filling the pores and cracks in the cured composite material and eliminating internal defects, resulting in a conductive plastic material.

[0100] The methods for preparing a conductive plastic material provided in the embodiments of this application involve preparing magnetic core-shell particles, grafting a carboxyl-modified conductive agent onto the magnetic core-shell particles to produce a magnetoelectric synergistic composite filler, and then aligning the particles in a rotating magnetic field to obtain a uniformly dispersed conductive plastic material. The resulting conductive plastic material exhibits excellent electrical conductivity, good magnetic properties, high stability, and ease of processing. Furthermore, the preparation process for the conductive plastic material is simple and amenable to industrial production.

[0101] In one possible embodiment, the interface enhancer is a silane coupling agent containing an epoxy group, and the mass ratio of the core material to the interface enhancer is 1:(1-4).

[0102] Exemplarily, the mass ratio of the core material to the interface enhancer is 1:1, 1:1.5, 1:2, 1:3, 1:4, or a range consisting of any two thereof.

[0103] The conductive plastic material prepared by the method for preparing the conductive plastic material provided in the embodiments of the present application has at least the following advantages:

[0104] 1. Magnetic-conductive synergistic drive: The Fe3O4 core in the magnetic core-shell particles generates a magnetic moment under a magnetic field, driving the grafted conductive agent to stretch along the magnetic field. The conductive PPy shell in the magnetic core-shell particles and the conductive agent grafted to the adjacent magnetic core-shell particles form a conductive path through π-π stacking, giving the conductive plastic material the ability of magnetic-conductive synergistic drive, achieving low PTV and high conductivity.

[0105] 2. The epoxy group in the interface enhancer reacts with the carboxyl group in the conductive agent to form a covalent bond, reducing the conductive network breakage caused by interface slip and improving the interface bonding of the conductive plastic material;

[0106] 3. PTV reduction: The magnetoelectric synergistic composite filler with a heterogeneous structure of "CNT-magnetic core-shell particles" formed by grafting the conductive agent CNT onto the magnetic core-shell particles can form a penetrating conductive network when the conductive agent content is 0.1wt% C, reducing the PTV by 80% compared to the existing technology, and making the conductive plastic material have better elasticity;

[0107] 4. Through the magnetization effect of the rotating magnetic field, the conductive plastic material is given a highly directional conductive path, and an anisotropic conductive network can be controllably constructed. The rotating magnetic field can realize the functions of axial magnetic field and radial rotation;

[0108] 5. Conductive plastic materials with a magnetoelectric synergistic filler content of 0.1wt%-10wt% are suitable for lightweight applications such as flexible electronic devices and antistatic coatings, including wearable sensors. When the magnetoelectric synergistic filler content is 10wt%-40wt%, they can meet high-performance requirements for electromagnetic shielding, highly conductive electrodes, and corrosion-resistant grounding materials. The anisotropic properties of conductive plastic materials offer unique advantages in emerging fields such as directional heat conduction and field-effect transistors.

[0109] To better understand the above exemplary embodiment of the method for preparing the conductive plastic material, the following further describes it with reference to specific examples. The following examples should not be construed as limiting the scope of implementation of this application.

[0110] Table 1 shows the mass fractions of the components in the examples of the conductive plastic material preparation method provided herein. As shown in Table 1, the present application provides the component masses of three different examples of the conductive plastic material preparation method: Formulation 1, Formulation 2, and Formulation 3. The specific preparation processes for each example of the conductive plastic material preparation method are described in detail below.

[0111] Table 1 is the mass fraction of each component in the embodiment of the preparation method of conductive plastic material

[0112] Recipe 1 Recipe 2 Recipe 3 Base material 100 copies 100 copies 100 copies Interface enhancer 0.3wt% 0.5wt% 0.8wt% Magnetoelectric synergistic composite fillers 0.1wt% 10wt% 40wt%

[0113] The matrix material is polypropylene particles, the interface enhancer is a silane coupling agent, and the conductive agent is CNT.

[0114] Example 1 of a method for preparing a conductive plastic material

[0115] (1) Materials were weighed according to formula 1 in Table 1, and Fe3O4 was coated with SiO2 and PPy to obtain magnetic core-shell particles; wherein the particle size of the prepared magnetic core-shell particles Fe3O4 was 50 nm, the thickness of the PPy shell was 15 nm, and the thickness of the SiO2 insulating layer was 10 nm.

[0116] (2) The magnetic core-shell particles were grafted onto CNTs, and a catalytic reaction was carried out at 60°C for 6 hours using 1-ethyl-(3-dimethylaminopropyl)carbodiimide as a catalyst to obtain a magnetoelectric synergistic composite filler with a grafting density of 5 core-shell particles / μm CNTs;

[0117] (3) melt-blending the magnetoelectric composite filler, silane coupling agent, and polypropylene particles at 170° C., and magnetizing them in a rotating magnetic field with an axial magnetic field of 30 mT and a radial rotation frequency of 3 Hz to obtain a molten composite material;

[0118] (4) The molten composite material is rapidly solidified in a liquid nitrogen cooling channel with a cooling rate of 60°C / s, and then hot-pressed to obtain a conductive plastic material A.

[0119] Example 2 of a method for preparing a conductive plastic material

[0120] (1) Materials were weighed according to formula 1 in Table 1, and Fe3O4 was coated with SiO2 and PPy to obtain magnetic core-shell particles; wherein the particle size of the prepared magnetic core-shell particles Fe3O4 was 50 nm, the thickness of the PPy shell was 15 nm, and the thickness of the SiO2 insulating layer was 10 nm.

[0121] (2) The magnetic core-shell particles were grafted onto CNTs, and a catalytic reaction was carried out at 60°C for 6 hours using 1-ethyl-(3-dimethylaminopropyl)carbodiimide as a catalyst to obtain a magnetoelectric synergistic composite filler with a grafting density of 5 core-shell particles / μm CNTs;

[0122] (3) melt-blending the magnetoelectric synergistic composite filler, silane coupling agent, and polypropylene particles at 170° C., and magnetizing them in a rotating magnetic field with an axial magnetic field of 40 mT and a radial rotation frequency of 4 Hz to obtain a molten composite material;

[0123] (4) The molten composite material is rapidly solidified in a liquid nitrogen cooling channel with a cooling rate of 70°C / s, and then hot-pressed to obtain a conductive plastic material B.

[0124] Example 3 of the preparation method of conductive plastic material

[0125] (1) Materials were weighed according to formula 1 in Table 1, and Fe3O4 was coated with SiO2 and PPy to obtain magnetic core-shell particles; wherein the particle size of the prepared magnetic core-shell particles Fe3O4 was 50 nm, the thickness of the PPy shell was 15 nm, and the thickness of the SiO2 insulating layer was 10 nm.

[0126] (2) The magnetic core-shell particles were grafted onto CNTs, and a catalytic reaction was carried out at 60°C for 6 hours using 1-ethyl-(3-dimethylaminopropyl)carbodiimide as a catalyst to obtain a magnetoelectric synergistic composite filler with a grafting density of 5 core-shell particles / μm CNTs;

[0127] (3) melt-blending the magnetoelectric synergistic composite filler, silane coupling agent, and polypropylene particles at 170° C., and magnetizing them in a rotating magnetic field with an axial magnetic field of 50 mT and a radial rotation frequency of 5 Hz to obtain a molten composite material;

[0128] (4) The molten composite material is rapidly solidified in a liquid nitrogen cooling channel with a cooling rate of 70°C / s, and then hot-pressed to obtain a conductive plastic material.

[0129] (5) The conductive plastic material C is subjected to surface plasma treatment at a power of 250 W and a treatment time of 8 minutes to obtain a conductive plastic material C.

[0130] In order to verify the effect of the technical solution of the present application, the resistivity of the prepared conductive plastic material was evaluated.

[0131] Those skilled in the art should understand that the test data results provided in this application are for reference only and do not fully define or guarantee that the experimental results will be exactly the same. The reproducibility of experimental results may be affected by many factors, including experimental conditions, operating techniques, and slight changes in the external environment.

[0132] Table 2 is a table of experimental test results of the embodiments of the present application. As shown in Table 2, the embodiments were tested.

[0133] Table 2 is the experimental test results of the embodiment of the present application

[0134]

[0135] The resistivity of conductive plastic material A, conductive plastic material B and conductive plastic material C in the direction parallel to the magnetic field is 1.1×10 3 , 35, and 0.5 Ω·m, indicating that conductive plastic material C has good electrical conductivity. Higher magnetic field strength and frequency were used in the preparation of conductive plastic material C, and plasma treatment was performed to further alter the surface properties of conductive plastic material C, resulting in a better resistivity in the direction parallel to the magnetic field.

[0136] The resistivity of conductive plastic material A, conductive plastic material B and conductive plastic material C in the direction perpendicular to the magnetic field is significantly higher than that in the direction parallel to the magnetic field, which is due to the anisotropy caused by the directional arrangement of the conductive plastic materials in the magnetic field.

[0137] The resistivity of conductive plastic material B in the direction parallel to the magnetic field is much lower than that of conductive plastic material A. Because the rotating magnetic field intensity during the magnetization of conductive plastic material B is higher than that of conductive plastic material A, the magnetic core-shell particles in conductive plastic material B can be arranged more orderly, thereby improving the conductivity of conductive plastic material B.

[0138] The above embodiments are merely examples of implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications, equivalent substitutions, and improvements without departing from the concept of the present invention, and these modifications are all within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the appended claims.

[0139] The preferred embodiments of the present application are described in detail above. However, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0140] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0141] In addition, the various implementation methods of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

[0142] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. It is not limited to the precise structure described above and shown in the drawings, and various modifications and changes may be made without departing from the scope of this application. The scope of this application is limited solely by the appended claims.

Claims

1. A conductive plastic material, characterized in that: The invention is composed of a matrix material, a magnetoelectric synergistic composite filler, and an interface enhancer; the magnetoelectric synergistic composite filler and the interface enhancer are uniformly mixed in the matrix material; wherein the matrix material is a thermoplastic polymer with a melt flow index greater than or equal to 20 g / 10 min and a melting point less than 180°C.

2. The conductive plastic material according to claim 1, characterized in that: The magnetoelectric synergistic composite filler is composed of magnetic core-shell particles and a conductive agent; wherein the core of the magnetic core-shell particles is Fe3O4, the surface of the core is coated with a SiO2 insulating layer, and the surface of the SiO2 insulating layer is coated with a conductive polypyrrole PPy shell layer.

3. The conductive plastic material according to claim 2, characterized in that: The particle size range of the core is 50nm-100nm, the thickness range of the PPy shell is 10nm-20nm, and the thickness range of the SiO2 insulating layer is 5nm-10nm.

4. The conductive plastic material according to claim 3, characterized in that: The conductive agent is modified carbon nanotubes; wherein the diameter of the modified carbon nanotubes ranges from 10 nm to 20 nm, and the length of the modified carbon nanotubes ranges from 10 μm to 50 μm.

5. The conductive plastic material according to claim 1, wherein: The interface enhancer is a silane coupling agent, and epoxy groups are added to the silane coupling agent; the addition amount of the interface enhancer is 0.3wt%-0.8wt%.

6. A method for preparing a conductive plastic material, characterized in that: For preparing the conductive plastic material according to any one of claims 1 to 5, the method comprises: The core material is coated with a first coating material and a second coating material to obtain magnetic core-shell particles; Grafting the magnetic core-shell particles with a conductive agent to obtain a magnetoelectric synergistic composite filler; The magnetoelectric synergistic composite filler, interface enhancer and matrix material are melt-blended and subjected to a magnetic field to obtain the conductive plastic material.

7. The method according to claim 6, characterized in that The core material is Fe3O4 nanoparticles, the first coating is ethyl orthosilicate, and the second coating is pyrrole. The core material is coated with the first coating and the second coating to obtain magnetic core-shell particles, including: Dispersing the core material in ethanol, adding the first coating material, and reacting sufficiently to obtain a first coating mixed solution; After drying the first coating mixed liquid, first coated particles are obtained; Dispersing the first coated particles in an aqueous solution containing a second coated material, adding ammonium persulfate initiator, and reacting for 4 hours under uniform stirring to obtain a second coated mixed solution; The precipitate obtained by centrifuging the second coating mixed solution is washed to obtain the magnetic core-shell particles. The centrifugation time of the centrifugation is 5 minutes to 10 minutes.

8. The method according to claim 6, characterized in that The interface enhancer is a silane coupling agent containing an epoxy group, and the mass ratio of the core material to the interface enhancer is 1:(1-4).

9. The method according to claim 6, characterized in that The step of grafting the magnetic core-shell particles with a conductive agent to obtain a magnetoelectric synergistic composite filler comprises: Acidifying the conductive agent with concentrated nitric acid to introduce carboxyl functional groups on the surface of the conductive agent to obtain a carboxyl-modified conductive agent; uniformly mixing the magnetic core-shell particles and the carboxyl-modified conductive agent in a mass ratio of 1:3 to obtain a first component; 1-Ethyl-(3-dimethylaminopropyl)carbodiimide was added as a catalyst to the first component, and a catalytic reaction was carried out at a temperature of 60° C. for 6 hours to obtain the magnetoelectric synergistic composite filler.

10. The method according to claim 6, characterized in that The method of melt-blending the magnetoelectric synergistic composite filler, the interface enhancer and the matrix material to obtain the conductive plastic material under the action of a magnetic field comprises: Melting and mixing the magnetoelectric synergistic composite filler with the matrix material to obtain a second component, wherein the magnetoelectric synergistic composite filler accounts for 0.1 wt% to 40 wt% of the second component; adding an interface enhancer to the second component and magnetizing the resultant in a rotating magnetic field to obtain a molten composite material, wherein the rotating magnetic field has an axial magnetic field strength in the range of 20 mT to 50 mT and a radial rotation frequency in the range of 2 Hz to 5 Hz; Rapidly solidifying the molten composite material through a liquid nitrogen cooling channel to lock the filler directional arrangement structure and obtain a solidified composite material; the cooling rate of the liquid nitrogen cooling channel is greater than or equal to 50°C / s; The conductive plastic material is obtained by eliminating internal defects of the cured composite material through hot pressing, wherein the temperature of the hot pressing is 150° C. and the pressure is 10 MPa.

Images