High-thermal-conductivity polyether ether ketone composite based on a spraying process and preparation method and application thereof

Abstract

The application belongs to the technical field of composite materials, and provides a high-thermal-conductivity polyether ether ketone composite material based on a spraying process, a preparation method and application thereof.Under the action of electrostatic spraying, the modified graphene and carbon nanotube soluble polymer solution are sprayed on both sides of a pure polyether ether ketone film, so that the composite filler is uniformly loaded on the surface of the pure polyether ether ketone film.Compared with the filler randomly dispersed composite material prepared by a melt blending method, the polyether ether ketone composite material prepared by the electrostatic spraying method forms a uniform and dense, oriented structure thermal and electrical conduction network.Meanwhile, the electrostatic spraying increases the physical contact area between the fillers, perfects the filler path, and fully plays the performance advantages of the high aspect ratio two-dimensional modified graphene nanosheet and carbon nanotube, provides a stable transmission path for phonons at a lower filling amount, reduces the interface scattering of phonons, improves the average free path of phonons, and enhances the electrical loss of electromagnetic waves.In addition, the modified graphene increases the interface interaction between the filler and the polymer, reduces the interface thermal resistance of the composite material, and further improves the thermal conductivity of the composite material.Therefore, the polyether ether ketone composite material provided by the application has excellent thermal conductivity and electromagnetic shielding performance.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a high thermal conductivity polyetheretherketone composite material based on a spraying process, its preparation method, and its application. Background Technology

[0002] Polyetheretherketone (PEEK), as a special engineering material, possesses excellent processing, mechanical, corrosion resistance, and thermal properties, making it highly valuable in military defense, automotive, and electronics fields. However, PEEK itself is a poor conductor of heat and electricity, limiting the application of PEEK composites in heat dissipation and electromagnetic shielding. Carbon-based fillers such as carbon fibers, carbon nanotubes, and graphene exhibit excellent electrical and thermal conductivity; therefore, modifying PEEK composites with carbon-based fillers is an effective method to improve their thermal conductivity and electromagnetic shielding performance.

[0003] Currently, Chinese patent CN109851776A discloses an in-situ polymerization method to fill carbon nanotubes into a polyaryletherketone (PEK) matrix. The π-π stacking effect between the carbon nanotubes and polymer molecular chains effectively disperses the filler, resulting in a composite material with good thermal conductivity. Chinese patent CN110746740A discloses a method of chemically plating nickel onto the surface of activated carbon nanotubes and then uniformly mixing PEVs, polyetherimides, and fillers using a screw extrusion method to obtain a PEV electromagnetic shielding material. While the composite materials prepared by these methods show some improvement in thermal conductivity and electromagnetic shielding performance, they still cannot meet current needs for functional PEVs and cannot fully utilize the excellent properties of the filler. Therefore, the distribution of the filler and the structural design of the filler network are key factors affecting the improvement of the thermal conductivity and electromagnetic shielding performance of the composite material. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a high thermal conductivity polyetheretherketone (PEEK) composite material based on a spray coating process, its preparation method, and its applications. The PEEK composite material prepared by the method provided by this invention exhibits excellent thermal conductivity and electromagnetic shielding properties.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a polyetheretherketone composite material, comprising the following steps:

[0007] The polymer and composite filler are dispersed in an organic solvent to obtain a spray coating solution;

[0008] After electrostatic spraying, the spray coating liquid is sprayed onto both surfaces of a pure polyether ether ketone film, and the resulting sandwich structure is melt-pressed to obtain the polyether ether ketone composite material.

[0009] The polymers include soluble polyarylethers and / or soluble polyarylether ketone polymers;

[0010] The composite filler includes modified graphene and carbon nanotubes.

[0011] Preferably, the soluble polyaryletherketone polymer includes one or more of polyetherketone imine, polyetherketone imine, biphenyl-type polyetherketone imine, and phenolphthalein-type polyetherketone.

[0012] Preferably, the mass ratio of the modified graphene to carbon nanotubes is (4:1) to (1:2).

[0013] Preferably, the modified graphene includes one or more of amino graphene, hydroxyl graphene, and carboxylated graphene.

[0014] Preferably, in the spray coating liquid, the concentration of the polymer is 2-6 mg / mL and the concentration of the composite filler is 3-7 mg / mL.

[0015] Preferably, the thickness of the pure polyether ether ketone film is 0.02 to 0.04 mm.

[0016] Preferably, the parameters for electrostatic spraying include: a spraying voltage of 40–70 kV, a distance of 10–30 cm between the nozzle and the pure polyether ether ketone film, and a spraying time of 10–50 min.

[0017] Preferably, the hot pressing includes preheating and hot pressing in sequence. The preheating temperature is 350-390°C and the time is 5-15 min. The hot pressing temperature is 350-390°C, the pressure is 15-25 MPa, and the holding time is 8-20 min.

[0018] The present invention also provides a polyetheretherketone composite material prepared by the preparation method described above, comprising a polymer-composite filler layer, a polyetheretherketone layer and a polymer-composite filler layer stacked together.

[0019] The present invention also provides the application of the polyetheretherketone composite material described above in military aviation, electronic information and medical devices.

[0020] This invention provides a method for preparing a polyetheretherketone (PEEK) composite material, comprising the following steps: dispersing a polymer and a composite filler in an organic solvent to obtain a spray coating liquid; spraying the spray coating liquid onto both surfaces of a pure PEEK film by electrostatic spraying; and then performing melt hot pressing on the resulting sandwich structure to obtain the PEEK composite material; wherein the polymer includes soluble polyarylethers and / or soluble polyaryletherketone polymers; and the composite filler includes modified graphene and carbon nanotubes.

[0021] Electrostatic spraying involves applying a coating liquid to both sides of a pure polyetheretherketone (PEEK) film, resulting in a uniform loading of the composite filler onto the film surface. Compared to composites prepared by melt blending, where the filler is randomly dispersed, the PEEK composite prepared by electrostatic spraying forms a denser, oriented thermally and electrically conductive pathway. Simultaneously, electrostatic spraying enhances the orientation of the modified graphene nanosheets and carbon nanotubes, increases the physical contact area between fillers, improves the filler pathways, and fully leverages the performance advantages of the high aspect ratio of the two-dimensional modified graphene nanosheets and carbon nanotubes. This provides a stable transport path for phonons with a lower filler content, reduces phonon interfacial scattering, and increases the mean free path of phonons. Therefore, the PEEK composite provided by this invention exhibits excellent thermal conductivity and electromagnetic shielding properties.

[0022] Furthermore, amino-graphene has better interfacial compatibility, which can reduce the interfacial thermal resistance of composite materials and further improve the thermal conductivity of composite materials. Attached Figure Description

[0023] Figure 1 This is a scanning electron microscope image of the cross-section of the composite material obtained in Example 5;

[0024] Figure 2 The DSC curve of the composite material obtained in Example 5;

[0025] Figure 3 The TGA curve of the composite material obtained in Example 5;

[0026] Figure 4 The electromagnetic shielding curve of the composite material obtained in Example 5 is shown. Detailed Implementation

[0027] This invention provides a method for preparing a polyetheretherketone composite material, comprising the following steps:

[0028] The polymer and composite filler are dispersed in an organic solvent to obtain a spray coating solution;

[0029] After electrostatic spraying, the spray coating liquid is sprayed onto both surfaces of a pure polyether ether ketone film, and the resulting sandwich structure is melt-pressed to obtain the polyether ether ketone composite material.

[0030] The polymers include soluble polyarylethers and / or soluble polyarylether ketone polymers;

[0031] The composite filler includes modified graphene and carbon nanotubes.

[0032] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0033] This invention disperses polymers and composite fillers in an organic solvent to obtain a spray coating liquid.

[0034] In this invention, the polymer comprises soluble polyarylethers and / or soluble polyaryletherketone polymers, preferably soluble polyaryletherketone polymers. In this invention, the soluble polyaryletherketone polymer preferably comprises one or more of polyetherketone imines, polyetheretherketone imines, biphenyl-type polyetheretherketone imines, and phenolphthalein-type polyetherketones.

[0035] In this invention, the preparation method of the biphenyl-type polyether ether ketone imine preferably includes the following steps:

[0036] A ketimine difluorinated monomer, 4,4'-biphenyl, a catalyst, a dehydrating agent, and a solvent are mixed and subjected to a first polymerization and a second polymerization sequentially to obtain the biphenyl-type polyether ether ketimine. In this invention, the catalyst preferably comprises one or more of sodium carbonate, potassium carbonate, and cesium carbonate. In this invention, the dehydrating agent preferably comprises one or more of benzene, toluene, and cyclopentane. In this invention, the solvent preferably comprises sulfolane and / or diphenyl sulfone. In this invention, the molar ratio of the ketimine difluorinated monomer to 4,4'-biphenyl is preferably 1:2 to 2:1, more preferably 1:1. In this invention, the molar ratio of the ketimine difluorinated monomer to the catalyst is preferably 1:1 to 1:2, more preferably 1:1.1. In this invention, the molar ratio of the ketimine difluorinated monomer to the dehydrating agent is preferably 1:5 to 1:10. In this invention, the mixing is preferably carried out in a three-necked flask. In this invention, the mixing is preferably carried out under a nitrogen atmosphere. In this invention, the temperature of the first polymerization is preferably 120–150°C, more preferably 140°C, and the time is preferably 2–5 hours, more preferably 3 hours. The first polymerization is preferably carried out under nitrogen protection. In this invention, the temperature of the second polymerization is preferably 170–200°C, more preferably 190°C, and the time is preferably 8–15 hours, more preferably 12 hours. The second polymerization is preferably carried out under nitrogen protection. After the second polymerization, this invention preferably further includes washing and drying the resulting second polymerization system; the washing reagent preferably includes methanol.

[0037] In this invention, the composite filler comprises modified graphene and carbon nanotubes. The mass ratio of the modified graphene to carbon nanotubes is preferably (4:1) to (1:2), more preferably (2:1) to (1:2), and even more preferably (2:1) to (1:1). The modified graphene preferably comprises one or more of aminographene, hydroxyl graphene, and carboxyl graphene.

[0038] In this invention, the preparation method of the amino-graphene preferably includes the following steps:

[0039] 4-4'-oxydiphenylamine is dissolved in dilute hydrochloric acid, cooled, and then sodium nitrite solution is added dropwise while stirring. The mixed solution is then added to a graphene dispersion and ultrasonically vibrated. After the reaction is complete, triethylamine is added, filtered, washed several times, and dried to obtain the aminographene. In this invention, the molar ratio of 4-4'-oxydiphenylamine to sodium nitrite is preferably 1:1 to 1:1.3; the mass ratio of 4-4'-oxydiphenylamine to graphene in the graphene dispersion is preferably 4:1 to 2:1. In this invention, the cooling is preferably carried out in an ice-water bath. In this invention, the stirring method is preferably mechanical stirring. In this invention, the dispersant of the graphene dispersion preferably includes an organic solvent and water, and the organic solvent preferably includes one or more of acetone, N-methylpyrrolidone, N,N-dimethylformamide, and dichloromethane. In this invention, the ultrasonic oscillation is preferably performed at a constant temperature of 50°C, and the ultrasonic oscillation time is preferably 20 hours. This invention does not impose any special limitation on the frequency of the ultrasonic oscillation; any ultrasonic frequency well-known to those skilled in the art can be used. In this invention, the filtration is preferably performed using a vacuum pump. In this invention, the washing reagent preferably includes N,N-dimethylformamide and water. This invention does not impose any special limitation on the drying process; any method that achieves thorough drying of the material is acceptable.

[0040] In this invention, the organic solvent preferably includes one or more of acetone, N-methylpyrrolidone, N,N-dimethylformamide, and dichloromethane.

[0041] In this invention, the dispersion of the polymer and composite filler in an organic solvent preferably includes: dispersing the polymer in an organic solvent to obtain a polymer solution; then adding the composite filler to the polymer solution and performing ultrasonic dispersion. This invention does not specifically limit the power and time of the ultrasonic dispersion, as long as the polymer, composite filler, and organic solvent are sufficiently mixed and dispersed.

[0042] In this invention, the concentration of the polymer in the spray coating liquid is preferably 2-6 mg / mL; the concentration of the composite filler is preferably 3-7 mg / mL, more preferably 3-6 mg / mL, and even more preferably 4-6 mg / mL.

[0043] After obtaining the spray coating liquid, the present invention sprays the spray coating liquid onto the two surfaces of the pure polyether ether ketone film by electrostatic spraying, and then melts and hot-presses the resulting sandwich structure to obtain the polyether ether ketone composite material.

[0044] In this invention, the thickness of the pure polyetheretherketone film is preferably 0.02–0.04 mm, more preferably 0.033 μm. In this invention, the dimensions of the pure polyetheretherketone film are preferably 30 cm × 20 cm × 0.033 mm.

[0045] In this invention, the parameters for electrostatic spraying include: a spraying voltage preferably of 40–70 kV, more preferably 60 kV; a distance between the nozzle and the pure polyether ether ketone film preferably of 10–30 cm, more preferably 20 cm; and a spraying time preferably of 10–50 min. In this invention, the filler loading can be controlled by adjusting the electrostatic spraying time.

[0046] After electrostatic spraying, the present invention preferably includes drying, wherein the drying temperature is preferably 40°C and the drying time is preferably 3 hours.

[0047] In this invention, the electric field force of electrostatic spraying facilitates the distribution of the conductive medium along the electric field direction, causing carbon nanotubes and modified graphene to form a layered structure along the thickness direction of the coating. This improves the orientation degree of the modified graphene nanosheets and carbon nanotubes, increases the physical contact area between fillers, and fully leverages the thermal conductivity advantages of the high aspect ratio two-dimensional modified graphene nanosheets and carbon nanotubes, effectively improving the thermal and electrical conductivity of the coating. Simultaneously, the layered structure forms a uniform and dense thermal and electrical conductive network, reducing filler aggregation and agglomeration, thereby reducing interfacial thermal resistance between fillers and lowering the insulation barrier. Furthermore, the layered thermal conductive pathways form a dense conduction path, providing a stable transmission path for phonons, reducing interfacial scattering, and extending the transmission path of electromagnetic waves, thus enhancing electromagnetic wave loss. Moreover, the modified graphene can increase the interfacial interaction between the filler and the polymer matrix, further improving the thermal conductivity of the composite material. Therefore, this polyetheretherketone composite material is a thermally conductive functional composite material with excellent application value.

[0048] In this invention, the hot pressing preferably includes preheating and hot pressing sequentially. The preheating temperature is preferably 350–390°C, more preferably 360–390°C, and even more preferably 370–385°C. The preheating time is preferably 5–15 min, more preferably 10–15 min, and even more preferably 10–12 min. The hot pressing temperature is preferably the same as the preheating temperature. The pressure is preferably 15–25 MPa, more preferably 20–25 MPa, and even more preferably 20–25 MPa. The heat holding and pressure holding time is preferably 8–20 min, more preferably 10–20 min, and even more preferably 15–20 min.

[0049] After the hot pressing, the present invention preferably further includes releasing the pressure and allowing natural cooling.

[0050] In this invention, electrostatic spraying uniformly loads composite fillers onto the surface of a pure polyether ether ketone (PEEK) film, which facilitates the formation of good thermal conductivity pathways, reduces phonon scattering, and provides a channel for high-speed phonon transmission. Furthermore, electrostatic action causes most of the composite fillers to align radially, and the hot-pressing process further enhances the in-plane orientation effect of the fillers, comprehensively improving the heat transfer efficiency of the composite material.

[0051] This invention also provides a polyetheretherketone (PEEK) composite material prepared by the method described in the above technical solution. In this invention, the PEEK composite material comprises a polymer-composite filler layer, a PEEK layer, and a polymer-composite filler layer stacked together. In this invention, the volume fraction of the composite filler in the PEEK composite material is 1-15%.

[0052] The present invention also provides the application of the polyetheretherketone composite material described above in military aviation, electronic information and medical devices.

[0053] The present invention does not impose specific limitations on the application of the polyetheretherketone composite material; those skilled in the art can make settings according to actual needs.

[0054] The following detailed description, in conjunction with embodiments, illustrates the high thermal conductivity polyether ether ketone composite material based on spraying process provided by the present invention, its preparation method, and its application. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0055] Example 1

[0056] First, the synthesis is carried out using the preparation method of the ketimine monomer and the biphenyl-type polyether ketimine polymer (when one or more reagents and their ratios are involved, this example only provides a separate listing, and therefore will not be listed in subsequent examples), and the specific steps are as follows:

[0057] In a 250 mL three-necked flask equipped with a mechanical stirrer, a Dean-Stark water separator, and a condenser, ketimine difluoromonomer (5.87 g, 20 mmol), 4,4'-biphenylhydroquinone (37.24 g, 20 mmol), anhydrous potassium carbonate (3.04 g, 22 mmol), toluene (20 mL), and sulfolane (30 mL) were added sequentially. The system was heated to 140 °C under a nitrogen atmosphere and maintained for 3 h to remove water generated during the reaction. The temperature was then increased to 190 °C, and the reaction was continued for 12 h to obtain a viscous polymer solution. This solution was discharged into methanol, washed several times, and then dried under vacuum to obtain a biphenyl-type polyether ether ketimine polymer.

[0058] Secondly, the synthesis of aminographene is carried out using the aforementioned method (when one or more reagents and their ratios are involved, this example only provides a separate illustration and will not be listed in subsequent embodiments), and the specific steps are as follows:

[0059] 4-4'-oxydiphenylamine (31.25 g, 156.25 mmol) was dissolved in 375 mL of water containing concentrated hydrochloric acid (45 mL, 525 mmol) and cooled at 5 °C. Sodium nitrite (11 g, 159.5 mmol) was dissolved in 125 mL of water until clear, and this solution was added dropwise to the acidic solution obtained in the previous step. After stirring for 30 min, the obtained solution was added to a dispersion of 2 mg / mL graphene (10 g) in N,N-dimethylformamide / water (N,N-dimethylformamide and water volume ratio of 5:3). The mixture was then placed in an ultrasonic oscillator at 50 °C and reacted for 20 h. After the reaction was complete, triethylamine (23.67 g, 234.38 mmol) was added to the system to convert the aromatic amine hydrochloride into the free aromatic amine. The filtered graphene was redispersed in N,N-dimethylformamide / water solution and washed several times, and then dried continuously in a vacuum oven at 80°C for 36 hours to obtain aminographene.

[0060] A 3 mg / mL biphenyl polyether ether ketone imine / dichloromethane solution was prepared, and then a composite filler (amino graphene and carbon nanotubes in a mass ratio of 1:1) was added to prepare a mixed suspension with a composite filler concentration of 5 mg / mL. The mixed suspension was then subjected to ultrasonic oscillation for 30 min to obtain a uniformly dispersed amino graphene, carbon nanotube / biphenyl polyether ether ketone imine solution.

[0061] Then, thermally conductive polyetheretherketone composite materials are prepared using electrostatic spraying and melt hot pressing methods, with the specific steps as follows:

[0062] Subsequently, a handheld electrostatic spray gun was used to electrostatically spray a pure polyetheretherketone (PEEK) film with dimensions of 30cm × 20cm × 0.033mm. The electrostatic spraying equipment was provided by Dongguan Taiben Automation Equipment Co., Ltd. Specific spraying conditions were as follows: under grounding conditions, the spraying voltage was set to 60kV, the distance between the nozzle and the PEEK film fixed on a uniformly rotating roller was 20cm, and the nozzle flow rate was controlled by adjusting the rear knob of the spray gun to achieve a good spraying effect. After single-sided spraying, the composite film was removed and dried in a 40℃ forced-air oven for 3 hours. The above steps were then repeated for double-sided spraying to finally obtain an amino-graphene / carbon nanotube / PEEK composite film. The spraying time was controlled to be 10 minutes to prepare an amino-graphene / carbon nanotube / PEEK composite film with a filler loading of 1.78 vol%. The resulting composite sheet was then obtained through melt hot pressing. The process conditions for hot-pressing are as follows: preheating at 380℃ for 15 minutes without pressure, holding at 20MPa for 10 minutes, and then removing the pressure and cooling naturally.

[0063] Example 2

[0064] A 3 mg / mL polyetherketone imine (prepared according to Susanta Banerjee, Chhaya Saxena, Pranav K. Gutch, Dinesh C. Gupta, European Polymer Journal, Pub Date: 1996-05-01, DOI: 10.1016 / 0014-3057(95)00178-6) / dichloromethane solution was prepared, and then the composite material (hydroxyl graphene and carbon nanotubes in a mass ratio of 1:1) was added to prepare a mixed suspension with a composite filler concentration of 5 mg / mL. The above mixed suspension was then subjected to ultrasonic oscillation for 30 min to obtain a uniformly dispersed hydroxyl graphene, carbon nanotube / polyetherketone imine solution.

[0065] The method for preparing the composite material is as follows:

[0066] Under grounded conditions, the spraying voltage was set to 60kV, and the distance between the nozzle and the polyetheretherketone (PEEK) film fixed on a uniformly rotating roller was 20cm. The nozzle flow rate was controlled by adjusting the rear knob of the spray gun to obtain a good spraying effect. After single-sided spraying, the composite film was removed and dried in a 40℃ forced-air oven for 3 hours. Then, the above steps were repeated for double-sided spraying to finally obtain a hydroxyl graphene / carbon nanotube / PEEK composite film. The spraying time was controlled to 20 minutes to prepare a hydroxyl graphene / carbon nanotube / PEEK composite film with a filler loading of 4.16 vol%. Then, the corresponding composite sheet was obtained by melt hot pressing. The melt hot pressing process conditions were: preheating at 380℃ for 15 minutes without pressure, holding at 20MPa for 10 minutes, and then removing the pressure and allowing it to cool naturally.

[0067] Example 3

[0068] A 3 mg / mL phenolphthalein-type polyetherketone (PAEKNM-01, purchased from Zhejiang Palco New Material Co., Ltd.) / dichloromethane solution was prepared, followed by the addition of composite filler (carboxylated graphene and carbon nanotubes in a mass ratio of 1:1) to prepare a mixed suspension with a composite filler concentration of 5 mg / mL. The mixed suspension was then subjected to ultrasonic oscillation for 30 min to obtain a uniformly dispersed carboxylated graphene, carbon nanotube / phenolphthalein-type polyetherketone solution.

[0069] The method for preparing the composite material is as follows:

[0070] Under grounded conditions, the spraying voltage was set to 60kV, and the distance between the nozzle and the polyetheretherketone (PEEK) film fixed on a uniformly rotating roller was 20cm. The nozzle flow rate was controlled by adjusting the rear knob of the spray gun to achieve a good spraying effect. After single-sided spraying, the composite film was removed and dried in a 40℃ forced-air oven for 3 hours. The above steps were then repeated for double-sided spraying to finally obtain a carboxylated graphene / carbon nanotube / PEEK composite film. The spraying time was controlled to 30 minutes to prepare a carboxylated graphene / carbon nanotube / PEEK composite film with a filler loading of 7.15 vol%. The corresponding composite sheet was then obtained through melt hot pressing. The melt hot pressing process conditions were: preheating at 380℃ for 15 minutes without pressure, holding at 20MPa for 10 minutes, and then removing the pressure and allowing natural cooling.

[0071] Example 4

[0072] A 3 mg / mL polyetheretherketone imine solution (prepared according to Sinan Feng, Cong Liu, Hung-Jue Sue, Composites Science and Technology (IF 9.1), Pub Date: 2022-01-29. DOI: 10.1016 / j.compscitech.2022.109298) / dichloromethane solution was prepared, and then a composite filler (carboxylated graphene and carbon nanotubes in a mass ratio of 1:1) was added to prepare a mixed suspension with a composite filler concentration of 5 mg / mL. The above mixed suspension was then subjected to ultrasonic oscillation for 30 min to obtain a uniformly dispersed carboxylated graphene, carbon nanotube / polyetheretherketone imine solution.

[0073] The preparation method of composite materials is as follows:

[0074] Under grounded conditions, the spraying voltage was set to 60kV, and the distance between the nozzle and the polyetheretherketone (PEEK) film fixed on a uniformly rotating roller was 20cm. The nozzle flow rate was controlled by adjusting the rear knob of the spray gun to achieve a good spraying effect. After single-sided spraying, the composite film was removed and dried in a 40℃ forced-air oven for 3 hours. The above steps were then repeated for double-sided spraying to finally obtain a carboxylated graphene / carbon nanotube / PEEK composite film. The spraying time was controlled to 40 minutes to prepare a carboxylated graphene / carbon nanotube / PEEK composite film with a filler loading of 8.94 vol%. The corresponding composite sheet was then obtained through melt hot pressing. The melt hot pressing process conditions were: preheating at 380℃ for 15 minutes without pressure, holding at 20MPa for 10 minutes, and then removing the pressure and allowing natural cooling.

[0075] Example 5

[0076] The preparation method of the suspension is the same as that in Example 1. The preparation method of the composite material is as follows:

[0077] Under grounded conditions, the spraying voltage was set to 60kV, and the distance between the nozzle and the polyetheretherketone (PEEK) film fixed on a uniformly rotating roller was 20cm. The nozzle flow rate was controlled by adjusting the rear knob of the spray gun to obtain a good spraying effect. After single-sided spraying, the composite film was removed and dried in a 40℃ forced-air oven for 3 hours. Then, the above steps were repeated for double-sided spraying to finally obtain an amino-graphene / carbon nanotube / PEEK composite film. The spraying time was controlled at 50 minutes to prepare an amino-graphene / carbon nanotube / PEEK composite film with a filler loading of 14.97 vol%. Then, the corresponding composite sheet was obtained by melt hot pressing. The melt hot pressing process conditions were: preheating at 380℃ for 15 minutes without pressure, holding at 20MPa for 10 minutes, and then removing the pressure and allowing it to cool naturally.

[0078] Comparative Example 1

[0079] The specific steps for preparing the biphenyl-type polyether ether ketone imine are the same as those in Example 1.

[0080] A 3 mg / mL biphenyl polyether ether ketone imine / dichloromethane solution was prepared, and then a composite filler (graphene and carbon nanotubes in a mass ratio of 1:1) was added to prepare a mixed suspension with a composite filler concentration of 5 mg / mL. The mixed suspension was then subjected to ultrasonic oscillation for 30 min to obtain a uniformly dispersed graphene, carbon nanotube / biphenyl polyether ether ketone imine solution.

[0081] Then, thermally conductive polyetheretherketone (PEEK) composite materials were prepared using electrostatic spraying and melt hot pressing, with the specific steps being the same as in Example 1. The spraying time was controlled at 50 minutes to prepare a graphene / carbon nanotube / PEEK composite film with a filler loading of 14.97 vol%. The corresponding composite sheet was then obtained by melt hot pressing. The melt hot pressing process conditions were: preheating at 380°C for 15 minutes without pressure, holding at 20 MPa for 10 minutes, and then removing the pressure and allowing natural cooling.

[0082] Comparative Example 2

[0083] 0.75 g each of graphene nanosheets and carbon nanotubes were weighed and dispersed in 272 mL of dichloromethane to obtain a mixed solution with a total filler concentration of 5 mg / mL. A relatively stable dispersion was obtained by ultrasonication for 30 min. Then, 4.5 g of pure polyetheretherketone (PEEK) was added and ultrasonically dispersed for 3 h, followed by continuous stirring for 24 h, yielding a graphene / carbon nanotube / PEEK composite material solution with a filler content of 14.97 vol%. The solution was filtered and washed with ethanol and water, then dried in a vacuum drying oven at 80 °C for 12 h. The resulting composite sheet was then obtained by melt hot pressing. The melt hot pressing process conditions were: preheating at 380 °C for 15 min without pressure, holding at 20 MPa for 10 min, followed by pressure removal and natural cooling.

[0084] The thermal conductivity coefficient of the obtained composite material was determined using a thermal conductivity tester (LFA467 flash method, Germany), and the results are shown in Table 1.

[0085] Table 1. Thermal conductivity of the composite materials obtained in the examples and comparative examples.

[0086] <![CDATA[Out-of-plane thermal conductivity W·m K -1 > 0.62 0.85 1.08 1.53 2.05 1.77 1.53 <![CDATA[in-plane thermal conductivity W·m -1 K -1 > 1.69 2.09 2.51 3.68 4.05 3.93 3.26

[0087] As shown in Table 1, the thermal conductivity of the composite material prepared by this invention gradually improves with increasing filler content. Examples 5 and 1 demonstrate that the modified graphene nanosheets significantly improve the thermal conductivity of the composite material. Examples 5 and 2 show that the layered composite material prepared by spraying exhibits much higher thermal conductivity than the randomly blended composite material at the same filler content.

[0088] Figure 1 The image shown is a cross-sectional scanning electron microscope image of the composite material obtained in Example 5. Figure 1 It can be seen that the filler is evenly spread on the surface of the pure polyether ether ketone film through atomization, forming a good thermal conductivity path.

[0089] Figure 2 The image shows the DSC curve of the composite material obtained in Example 5.

[0090] Figure 3 The TGA curve of the composite material obtained in Example 5 is shown below. Figure 3 It can be seen that the initial thermal decomposition temperature of the composite material is about 500℃, indicating that the composite material has good thermal stability.

[0091] Figure 4 The electromagnetic shielding curve of the composite material obtained in Example 5 is shown below. Figure 4 It can be seen that the composite material achieves the best electromagnetic shielding performance of 40.6dB at 12.4GHz, which is far higher than the commercial standard (20dB), demonstrating a good electromagnetic shielding effect.

[0092] At 12.4 GHz, the electromagnetic shielding results of the composite materials obtained in Examples 1-5 and Comparative Examples 1-2 are shown in Table 2.

[0093] Table 2 Electromagnetic shielding performance of the composite materials obtained in the examples at 12.4 GHz

[0094] Electromagnetic shielding performance dB 13.2 17.5 22.3 28.7 40.6 37.2 29.8

[0095] As can be seen from the above embodiments, the layered thermally conductive and electromagnetically shielding polyether ether ketone composite material provided by the present invention has excellent thermal conductivity.

[0096] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyetheretherketone composite material, characterized in that, Includes the following steps: The polymer and composite filler are dispersed in an organic solvent to obtain a spray coating solution; After electrostatic spraying, the spray coating liquid is applied to both surfaces of a pure polyether ether ketone film, and the resulting sandwich structure is melt-pressed to obtain the polyether ether ketone composite material. The polymers include soluble polyarylethers and / or soluble polyarylether ketone polymers; The composite filler includes modified graphene and carbon nanotubes; The soluble polyaryletherketone polymers include one or more of polyetherketone imines, polyetheretherketone imines, biphenyl-type polyetheretherketone imines, and phenolphthalein-type polyetherketones. The mass ratio of the modified graphene to carbon nanotubes is (4:1) to (1:2); The modified graphene includes one or more of amino graphene, hydroxyl graphene, and carboxyl graphene. In the spray coating liquid, the concentration of the polymer is 2~6 mg / mL, and the concentration of the composite filler is 3~7 mg / mL; The thickness of the pure polyetheretherketone film is 0.02~0.04 mm; The parameters for electrostatic spraying include: a spraying voltage of 40~70kV, a distance of 10~30cm between the nozzle and the pure polyether ether ketone film, and a time of 10~50min. The hot pressing process includes preheating and hot pressing in sequence. The preheating temperature is 350~390℃ and the time is 5~15min. The hot pressing temperature is 350~390℃, the pressure is 15~25MPa, and the holding time is 8~20min.

2. The polyetheretherketone composite material prepared by the method of claim 1, characterized in that, It includes a polymer-composite filler layer, a polyetheretherketone layer, and a polymer-composite filler layer stacked together.

3. The application of the polyetheretherketone composite material according to claim 2 in military aviation, electronic information and medical devices.

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