CN113337077B - High-thermal-conductivity electromagnetic shielding polyether-ether-ketone composite material with isolation structure and preparation method and application thereof - Google Patents

Abstract

The invention provides a high-thermal-conductivity electromagnetic shielding polyether-ether-ketone composite material with an isolation structure, and a preparation method and application thereof, and belongs to the technical field of composite materials. According to the invention, the carbon nano tube and the graphene are used as synergistic hybrid fillers, so that the contact area between the fillers is increased, the establishment of a filler network is facilitated, and the transmission effectiveness is improved; introducing polybenzoxazine with hydrogen bond effect to respectively modify and compound the polyetheretherketone and the hybrid filler to obtain polyetheretherketone composite particles with hybrid filler as a skin layer, polybenzoxazine as an adhesion layer and polyetheretherketone particles as a core, and obtaining the high-thermal-conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure through crosslinking curing and melting hot pressing. According to the invention, the benzoxazine polymer layer is used for modifying the polyether-ether-ketone and constructing the isolation structure, so that a stable and efficient heat conduction and transmission network is formed, the interface compatibility of the filler and the polymer is improved, the interface thermal resistance is reduced, and the heat conduction and electromagnetic shielding performance is good.

Description

A kind of high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure and preparation method and application thereof

technical field

The invention relates to the technical field of composite materials, in particular to a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure and a preparation method and application thereof.

Background technique

With the innovation of advanced wireless communication technology, the application of electronic chips in some industries, especially in the fields of military, aerospace, machinery, energy, etc., puts forward higher requirements for the densification, integration and light weight of chips. However, the miniaturization of electronic devices and circuits is accompanied by a large amount of thermal energy accumulation, and heat dissipation has become a key factor affecting stability, reliability, and life. It affects the transmission performance of the signal system, and will seriously endanger human health and environmental friendliness. The absorption and conversion of electromagnetic waves into heat energy is one of the common ways to reduce electromagnetic pollution, but this exacerbates the problem of thermal diffusion. Therefore, thermally conductive composites with electromagnetic shielding properties have been attracting much attention. However, functional composite materials based on general-purpose plastics are difficult to meet under harsh conditions, such as military and aerospace applications with high temperature resistance, strong mechanical properties or high electromagnetic shielding requirements.

Polyetheretherketone (PEEK) is a semi-crystalline special engineering plastic. Compared with ordinary general-purpose plastics, it has excellent thermal stability (long-term use temperature is 260 ° C, melting temperature is 340 ° C), excellent thermal stability. Mechanical properties and chemical stability. Therefore, PEEK-based thermally conductive electromagnetic shielding materials are widely used. However, due to the low thermal conductivity of PEEK itself (about 0.2W·m ^-1 ·K ^-1 ), its shielding performance is also poor. At the same time, because PEEK is almost insoluble in conventional solvents, it greatly increases the difficulty of covalent or non-covalent modification work. Therefore, obtaining PEEK composites with good thermal/conductive properties remains challenging.

At present, constructing a good filler transport network and selecting a filler system with synergistic effect are effective methods to improve the thermal/conductive properties of composites. For example, Chinese patent CN110527247B discloses the preparation of polyetheretherketone/multi-walled carbon nanotube composite material by in-situ polymerization, and dispersing it in the graphene nanosheet network by ball milling and hot pressing to obtain double-walled carbon nanotubes with excellent performance. Network structure polyetheretherketone thermally conductive composites. Chinese patent CN107459770B discloses the preparation of polyether ether ketone composite materials with high thermal conductivity and high stability by using silicon carbide, boron nitride and basalt fibers as synergistic thermal conductive fillers. However, the thermal conductivity of the polyetheretherketone composite material prepared by the above method is only improved to a certain extent and cannot meet the application requirements of shielding performance.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure and a preparation method and application thereof. The high thermal conductivity electromagnetic shielding polyether ether ketone composite material provided by the present invention The material has high thermal conductivity and excellent electromagnetic shielding performance.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a preparation method of a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure, comprising the following steps:

(1) ultrasonic modification is carried out by mixing multi-walled carbon nanotubes, graphene nanosheets, benzoxazine and soluble benzoxazine solvent to obtain a modified hybrid filler dispersion;

(2) mixing polyether ether ketone, benzoxazine and soluble benzoxazine solvent to carry out ultrasonic modification to obtain modified polyether ether ketone dispersion;

(3) mixing the modified hybrid filler dispersion with the modified polyetheretherketone dispersion, and performing vacuum shear-assisted mixing to obtain polyetheretherketone composite particles;

(4) curing and cross-linking the polyether ether ketone composite particles and melt hot pressing in turn to obtain a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure;

Step (1) and step (2) have no time sequence.

Preferably, the mass ratio of the multi-walled carbon nanotubes and the graphene nanosheets is 1-5:1.

Preferably, the ratio of the total mass of the multi-walled carbon nanotubes and the graphene nanosheets to the mass of the benzoxazine is 100:1-10.

Preferably, the particle size of the polyether ether ketone is 15-1000 mesh.

Preferably, the mass ratio of the polyether ether ketone to the benzoxazine is 10-100:1.

Preferably, the curing cross-linking comprises the first curing cross-linking, the second curing cross-linking and the third curing cross-linking performed in sequence;

The temperature of the first curing and crosslinking is 130-150°C, and the holding time is 1-2h;

The temperature of the second curing and crosslinking is 170-190°C, and the holding time is 2-3h;

The temperature of the third curing and crosslinking is 210-230° C., and the holding time is 1-2 hours.

Preferably, the temperature of the melt hot pressing is 370-390° C., and the pressure is 10-50 MPa.

The present invention provides a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure obtained by the preparation method described in the above technical solution.

Preferably, the volume fraction of the hybrid filler in the high thermal conductivity electromagnetic shielding polyetheretherketone composite material with isolation structure is 1-20%.

The invention provides the application of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with the isolation structure described in the above technical solution in the automobile industry, military and aerospace.

The invention provides a preparation method of a high thermal conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure, comprising the following steps: (1) combining multi-walled carbon nanotubes, graphene nanosheets, benzoxazine and soluble The benzoxazine solvent is mixed for ultrasonic modification to obtain a modified hybrid filler dispersion; (2) the polyether ether ketone, benzoxazine and soluble benzoxazine solvents are mixed for ultrasonic modification to obtain a modified polyether ether ether ketone dispersion liquid; (3) mixing the modified hybrid filler dispersion liquid and modified polyether ether ketone dispersion liquid, and performing vacuum shear-assisted mixing to obtain polyether ether ketone composite particles; (4) mixing the The polyetheretherketone composite particles are sequentially cured and crosslinked and melted and hot pressed to obtain a high thermal conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure; step (1) and step (2) have no time sequence. The invention adopts multi-walled carbon nanotubes and graphene nanosheets as hybrid fillers, benzoxazine as hybrid fillers and modifiers of polyetheretherketone, and adopts vacuum-assisted method, thermally cross-linked polymer modification method and melting method. The high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure was successfully prepared by hot pressing method. In the present invention, the hybrid filler is extruded from the polyether ether ketone polymer phase and enriched and continuously overlapped during the melt hot pressing process to form a conductive network (i.e. isolation structure), which is conducive to the rapid transmission of phonons and facilitates the conduction and diffusion of heat. Compared with the common melt blending method, the preparation method provided by the present invention can obtain a special isolation structure, and the isolation structure can form a relatively complete heat transfer network with a lower filler content. At the same time, the synergistic "nano-micro bridge" effect in the isolation structure increases the contact area (point-line, point-surface, line-surface) between the hybrid fillers, which is beneficial to acoustic heat conduction and heat dissipation, and is very beneficial to improve the material thermal conductivity. By introducing thermosetting polybenzoxazine polymer to modify polyether ether ketone matrix and hybrid filler, hydrogen bond interaction between polybenzoxazine and hybrid filler and polyether ether ketone, hydrogen bond interaction It can reduce the strong intramolecular π-π interaction of the hybrid filler itself, thereby improving the dispersion of the hybrid filler and reducing the contact thermal resistance. Compared with the van der Waals interaction, the existence of hydrogen bonds makes the phonon in the polymer of the composite material. The transfer resistance between the links decreases, and thus the transport rate of phonons increases rapidly in the filler-polymer layer-polymer matrix pathway, reducing the interfacial thermal resistance of the composite system. It can be seen that the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure provided by the present invention has excellent electrical conductivity, thermal conductivity and electromagnetic shielding performance.

The present invention provides a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure obtained by the preparation method described in the above technical solution. The high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure provided by the present invention has excellent electrical conductivity, thermal conductivity and electromagnetic shielding performance. The thermal conductivity in the vertical direction of the polyetheretherketone composite material is 0.4-3.338W/mK, the thermal conductivity in the parallel direction is 0.531-6.27W/mK, and the electrical conductivity is 0.12-524S/m. It has an isolation structure within 8-12GHz. The total shielding performance of the high thermal conductivity electromagnetic shielding polyetheretherketone composite material fluctuates within 60-80dB, and the shielding efficiency reaches more than 99.996%. It has good application prospects in the automotive industry, military and aerospace.

Description of drawings

1 is a schematic diagram of the thermal conductivity and electromagnetic shielding performance improvement of a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure in the present invention; wherein, (a) is a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure. The schematic diagram of the thermal conductivity improvement of the material, (b) is the schematic diagram of the shielding efficiency improvement of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with the isolation structure;

Fig. 2 is the process flow diagram of preparing the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure according to the embodiment;

Fig. 3 is the scanning electron microscope image of polyetheretherketone composite particles before and after melting and hot pressing in Example 4, wherein (a) is the scanning electron microscope image of polyetheretherketone composite particles before melting and hot pressing, and (b) is the melting and hot pressing SEM image of the obtained high thermal conductivity electromagnetic shielding polyetheretherketone composite material with isolation structure;

Fig. 4 is the shielding performance diagram of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure prepared in Example 6;

FIG. 5 is a thermogravimetric analysis diagram of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure prepared in Example 2. FIG.

Detailed ways

The invention provides a preparation method of a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure, comprising the following steps:

(1) ultrasonic modification is carried out by mixing multi-walled carbon nanotubes, graphene nanosheets, benzoxazine and soluble benzoxazine solvent to obtain a modified hybrid filler dispersion;

(2) mixing polyether ether ketone, benzoxazine and soluble benzoxazine solvent to carry out ultrasonic modification to obtain modified polyether ether ketone dispersion;

(3) mixing the modified hybrid filler dispersion with the modified polyetheretherketone dispersion, and performing vacuum shear-assisted mixing to obtain polyetheretherketone composite particles;

(4) curing and cross-linking the polyether ether ketone composite particles and melt hot pressing in turn to obtain a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure;

Step (1) and step (2) have no time sequence.

In the present invention, unless otherwise specified, all raw material components are commercially available commodities well known to those skilled in the art.

In the invention, the multi-walled carbon nanotubes, the graphene nanosheets, the benzoxazine and the soluble benzoxazine solvent are mixed for ultrasonic modification to obtain a modified hybrid filler dispersion. In the present invention, the length of the multi-walled carbon nanotubes (MWCNTs) is preferably 8-15 μm, and the diameter is preferably 45-90 nm; the length of the graphene nanosheets (GnPs) is preferably 7-15 μm, and the thickness is preferably 7-15 μm. is 6-10 nm; the mass ratio of the multi-walled carbon nanotubes and the graphene nanosheets is preferably 1-5:1, more preferably 2-4:1, and even more preferably 3:1. In the present invention, the mass ratio of the total mass of the multi-walled carbon nanotubes and the graphene nanosheets to the benzoxazine (PBZ) is preferably 100:1-10, more preferably 100:3-8. In the present invention, the mixing is not particularly limited, as long as the raw materials can be mixed and dispersed uniformly. In the present invention, the mixing sequence is preferably dissolving benzoxazine in a soluble benzoxazine solvent to obtain a benzoxazine solution; adding multi-walled carbon nanotubes to the benzoxazine solution mixed with graphene nanosheets. The present invention does not have a special limitation on the type of the soluble benzoxazine solvent, as long as the benzoxazine can be dissolved, such as a ketone-based solvent, and the ether-based solvent preferably includes acetone and/or butanone; The concentration of the oxazine solution is preferably 1.25 to 10 wt %, more preferably 2 to 8 wt %, and further preferably 5 to 6 wt %. In the present invention, the solid content of the modified hybrid filler dispersion liquid (that is, the content of the modified hybrid filler) is preferably 1-8 g/L, more preferably 2-6 g/L, still more preferably 3-5 g/L. In the present invention, the mixing is not particularly limited, as long as the raw materials can be mixed and dispersed uniformly. In the present invention, the frequency of the ultrasonic modified ultrasonic is preferably 40-100Mpa, more preferably 50-80Mpa; the ultrasonic time is preferably 3-6h, more preferably 4-5h; the ultrasonic is preferably in the ultrasonic During the ultrasonic modification process, the closely packed crystal fillers are exfoliated and dispersed under the action of oscillation, so that the benzoxazine modifier enters the interlayer, reduces the π-π interaction between the fillers, and improves the The interfacial compatibility of modified hybrid fillers and polyether ether ketone polymers when compounded.

In the present invention, polyether ether ketone, benzoxazine and soluble benzoxazine solvent are mixed for ultrasonic modification to obtain a modified polyether ether ketone dispersion liquid. In the present invention, the particle size of the polyetheretherketone (PEEK) is preferably 15-1000 meshes, more preferably 100-500 meshes. In the present invention, the mass ratio of the polyether ether ketone to the benzoxazine is preferably 10-100:1, more preferably 30-80:1, further preferably 50-60:1; The mixing is not particularly limited, and the raw materials can be mixed and dispersed evenly; the mixing sequence is preferably dissolving benzoxazine in a soluble benzoxazine solvent to obtain a benzoxazine solution; mixing the benzoxazine The oxazine solution is mixed with polyetheretherketone. The present invention does not have a special limitation on the type of the soluble benzoxazine solvent, as long as the benzoxazine can be dissolved, such as a ketone-based solvent, and the ether-based solvent preferably includes acetone and/or butanone; The concentration of the oxazine solution is preferably 1.25-10wt%, more preferably 2-8wt%, further preferably 5-6wt%. In the present invention, the frequency of the ultrasonic modified ultrasonic is preferably 40-100MHz, more preferably 50-80MHz; the ultrasonic time is preferably 1-6h, more preferably 3-4h; the ultrasonic is preferably carried out in an ultrasonic oscillator; in the ultrasonic modification process, the surface layer of polyetheretherketone is evenly coated with benzoin Oxazine polymer modifier.

After the modified hybrid filler dispersion liquid and the modified polyether ether ketone dispersion liquid are obtained, the present invention mixes the modified hybrid filler dispersion liquid and the modified polyether ether ketone dispersion liquid, and performs vacuum shear-assisted mixing to obtain polyether Ether ketone composite particles. In the present invention, the mass ratio of the modified hybrid filler in the modified hybrid filler dispersion to the modified polyetheretherketone in the modified polyetheretherketone dispersion is preferably 1-50:50-99, more preferably 10-40:60-90, More preferably, it is 20-30:70-80. In the present invention, the mixing is not particularly limited, as long as the raw materials can be mixed and dispersed uniformly. In the present invention, the method of vacuum shear-assisted mixing is preferably slow-release vacuum-assisted filtration; the vacuum shear-assisted mixing is performed under the action of a certain shear force, and a more complete structural polymer can be obtained by vacuum shear-assisted mixing. The ether ether ketone composite particles, the skin layer of the polyether ether ketone composite particles are mixed fillers, the adhesion layer is polybenzoxazine, and the core is the polyether ether ketone composite particles of the polyether ether ketone particles.

After the polyetheretherketone composite particles are obtained, the present invention melts and hot-presses the polyetheretherketone composite particles to obtain a high thermal conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure. In the present invention, the curing crosslinking preferably includes the first curing crosslinking, the second curing crosslinking and the third curing crosslinking performed in sequence; the temperature of the first curing crosslinking is preferably 130-150° C., more Preferably, it is 140°C; the holding time of the first curing and crosslinking is preferably 1-2h, more preferably 1.5h; the temperature of the second curing and crosslinking is preferably 170-190°C, more preferably 180°C; The holding time of the second curing and cross-linking is preferably 2 to 3 hours, more preferably 2.5 hours; the temperature of the third curing and cross-linking is preferably 210 to 230° C., more preferably 220° C. The third curing and cross-linking The holding time is preferably 1-2h, more preferably 1.5h; the curing and cross-linking is preferably carried out in an oven; during the curing and cross-linking process, part of the oxazine ring is ring-opened to generate a phenolic hydroxyl prepolymer (the first cross-linking). At higher temperatures (second cross-linking curing), the oxazine ring continues to open and hetero-cleave to generate cationic active centers, which react and combine with other molecules to achieve chain growth and generate aryl ether structures; further increase the temperature (Third cross-linking curing), increase the curing rate, increase the cross-linking density, and obtain a polymer similar to phenolic resin, with strong intermolecular and intramolecular hydrogen bonding; It is beneficial to control the integrity of the overall cross-linked structure and improve the thermal conductivity, electrical conductivity and overall performance of electromagnetic shielding of the composite material.

In the present invention, the temperature of the hot-melt pressing is preferably 370-390°C, more preferably 380°C; the pressure of the hot-melting pressing is preferably 10-50 MPa, more preferably 20-40 MPa. In the present invention, the polyether ether ketone is melted during the melting and hot pressing process, the mixed filler is macroscopically wrapped, and further molded to obtain a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure.

The present invention provides a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure obtained by the preparation method described in the above technical solution.

In the present invention, a schematic diagram of the thermal conductivity and electromagnetic shielding performance improvement of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure is shown in FIG. 1 , wherein (a) is a high thermal conductivity electromagnetic A schematic diagram of the thermal conductivity improvement of the shielding polyetheretherketone composite material, (b) is a schematic diagram of the shielding efficiency improvement of the high thermal conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure. It can be seen from (a) that the isolation structure in the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure provided by the present invention provides more heat transfer paths and builds a good thermal conduction network, and at the same time, the synergistic effect of hybrid fillers The contact area between the fillers is increased, which jointly reduces the scattering of phonons and improves the heat transfer performance; it can be seen from (b) that the isolation in the high thermal conductivity electromagnetic shielding polyether ether ketone composite material provided by the present invention has an isolation structure. The structure promotes the formation of more conductive interfaces, increases the number of multiple reflections inside the material, prolongs its propagation path and energy consumption, reduces the transmission of electromagnetic waves, and further improves the shielding performance of electromagnetic waves.

The present invention also provides the application of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with the isolation structure described in the above technical solution in the automobile industry, military and aerospace.

In the present invention, the application of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure in automobiles preferably includes as ABS brake pads or clutches in engine inner covers, automobile bearing transmission, braking and air conditioning systems Ring gears are also preferably used in the manufacture of turbo compressors, pumps, valves, electrical cables, seat adjustment parts or standard parts. In the present invention, the application of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with isolation structure in aerospace preferably includes replacing aluminum metal pipes to protect high-voltage cables, main load-bearing components or parts of air regeneration systems applications in . In the present invention, the application of the high thermal conductivity electromagnetic shielding polyether ether ketone composite material with the isolation structure in the military preferably includes the application in the aircraft parts of fighter jets for preventing electromagnetic interference.

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Using the process flow chart shown in Figure 2, a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure is prepared by a vacuum-assisted method, a thermally cross-linked polymer modification method and a melt hot pressing method. The specific steps are as follows:

Add 0.05g MWCNTs and 0.2g GnPs to 250mL of PBZ acetone solution with a concentration of 1.25wt%, mix and disperse uniformly, and sonicate for 3h in an ultrasonic oscillator at 60MHz at room temperature to obtain a modified hybrid filler dispersion. 9.75 g of PEEK with a particle size of 200 mesh was added to 450 mL of PBZ acetone solution with a concentration of 1.25 wt %, and sonicated at 60 MHz in an ultrasonic oscillator for 1 h at room temperature to obtain a modified polyether ether ketone dispersion. The modified hybrid filler dispersion liquid and the modified polyether ether ketone dispersion liquid are mixed to carry out slow-release vacuum-assisted filtration treatment to obtain polyether ether ketone composite particles. The polyether ether ketone composite particles were placed in an oven for 1 hour at 140°C, 2 hours at 180°C, and 2 hours at 210°C, and then melted and hot pressed at 380°C and 30Mpa to obtain a High thermal conductivity electromagnetic shielding polyether ether ketone composite material of isolation structure.

Example 2

According to the method of Example 1, a high thermal conductivity electromagnetic shielding polyether ether ketone composite material with an isolation structure was prepared, and the preparation conditions of Examples 2 to 6 are shown in Table 1.

Table 1 Preparation conditions of Examples 1 to 6

Comparative Example 1

0.125g MWCNTs, 0.125g GnPs and 9.75g PEEK (1000 mesh) were mixed and stirred under a high-speed mixer, and then melted and hot pressed at 380°C and 30Mpa to obtain a polyetheretherketone composite material.

Table 2 shows the test results of thermal conductivity and electrical conductivity of the composite materials prepared in Examples 1 to 6 and Comparative Example 1.

Among them, the thermal conductivity tester used in the thermal conductivity test is the flash method LFA467, Germany. The conductivity tester utilized for the conductivity test was a four-probe resistivity tester 2450 SourceMeter, KEITHLEY.

Table 2 Test results of thermal conductivity and electrical conductivity of the composites prepared in Examples 1 to 6 and Comparative Example 1

It can be seen from Table 2 that the composite material prepared by the present invention has excellent thermal conductivity and electrical conductivity.

Fig. 3 is the scanning electron microscope image of polyetheretherketone composite particles before and after melting and hot pressing in Example 4, wherein (a) is the scanning electron microscope image of polyetheretherketone composite particles before melting and hot pressing, and (b) is the melting and hot pressing Scanning electron microscope images of the obtained composites. Fig. 3 shows that the isolation structure in the composite material provided by the present invention has been well constructed.

Figure 4 is a diagram of the shielding performance of the composite material prepared in Example 6. It can be seen from Figure 4 that the total shielding performance of the composite material within 8-12 GHz fluctuates within 60-80 dB, and the shielding efficiency reaches more than 99.996%. The composite material has excellent electromagnetic shielding properties.

Fig. 5 is the thermogravimetric analysis diagram of the composite material prepared in Example 2, the temperature of T ₅ (5% weight loss) is 550°C, and the temperature of T ₁₀ (10% weight loss) is 580°C, indicating that the composite material prepared by the present invention has Excellent thermal stability.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A preparation method of a high-thermal-conductivity electromagnetic shielding polyether-ether-ketone composite material with an isolation structure comprises the following steps:

(1) mixing a multi-walled carbon nanotube, a graphene nanosheet, benzoxazine and a soluble benzoxazine solvent for ultrasonic modification to obtain a modified hybrid filler dispersion liquid;

(2) mixing polyether-ether-ketone, benzoxazine and a soluble benzoxazine solvent for ultrasonic modification to obtain a modified polyether-ether-ketone dispersion liquid;

(3) mixing the modified hybrid filler dispersion liquid and the modified polyether-ether-ketone dispersion liquid, and performing vacuum shearing assisted mixing to obtain polyether-ether-ketone composite particles;

(4) sequentially carrying out curing crosslinking and melting hot pressing on the polyether-ether-ketone composite particles to obtain the high-thermal-conductivity electromagnetic shielding polyether-ether-ketone composite material with the isolation structure;

the step (1) and the step (2) have no chronological sequence.

2. The preparation method of claim 1, wherein the mass ratio of the multi-walled carbon nanotube to the graphene nanosheet is 1-5: 1.

3. the method according to claim 1, wherein the ratio of the total mass of the multi-walled carbon nanotubes and graphene nanoplatelets to the mass of benzoxazine is 100: 1 to 10.

4. The preparation method according to claim 1, wherein the particle size of the polyetheretherketone is 15-1000 mesh.

5. A preparation method according to claim 1 or 4, wherein the mass ratio of the polyether-ether-ketone to the benzoxazine is 10-100: 1.

6. the production method according to claim 1, wherein the cured crosslinking includes a first cured crosslinking, a second cured crosslinking, and a third cured crosslinking that are performed in this order;

the temperature of the first curing crosslinking is 130-150 ℃, and the heat preservation time is 1-2 h;

the temperature of the second curing crosslinking is 170-190 ℃, and the heat preservation time is 2-3 h;

the temperature of the third curing crosslinking is 210-230 ℃, and the heat preservation time is 1-2 h.

7. The method according to claim 1, wherein the temperature of the melt hot pressing is 370 to 390 ℃ and the pressure is 10 to 50 MPa.

8. The high-thermal-conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure, which is obtained by the preparation method of any one of claims 1 to 7.

9. The high-thermal-conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure according to claim 8, wherein the volume fraction of the hybrid filler in the high-thermal-conductivity electromagnetic shielding polyetheretherketone composite material with an isolation structure is 1-20%.

10. The use of the high thermal conductivity electromagnetic shielding polyetheretherketone composite material with an insulation structure of any of claims 8 to 9 in the automotive industry, military and aerospace.

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