A method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material.

Abstract

This invention provides a method for preparing a fluorinated polyetheretherketone (PEEK) composite material with thermal conductivity and electromagnetic shielding properties, comprising the following steps: synthesizing soluble fluorinated PEEKs with different degrees of fluorination by controlling the ratio of hexafluorobisphenol A and hydroquinone; mixing the fluorinated PEEKs with a composite filler of carbon nanotubes and graphene nanosheets, and hot-pressing the mixture to prepare the fluorinated PEEK composite material. The introduction of fluorinated groups enhances the interfacial bonding force between the filler and the polymer matrix, reducing phonon interfacial scattering; the synergistic effect of carbon nanotubes and graphene nanosheets increases the contact area between the fillers, improving the thermal and electrical conductivity pathways; and molecular-level solution blending improves the distribution of the filler in the matrix, enhancing conductivity. The preparation method of the fluorinated PEEK composite material of this invention is simple and possesses excellent thermal conductivity and electromagnetic shielding properties.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation, specifically to a method for preparing a fluorinated polyether ether ketone thermally conductive and electromagnetically shielding composite material. Background Technology

[0002] As a semi-crystalline polymer, polyetheretherketone (PEEK) possesses advantages such as high heat resistance, corrosion resistance, impact resistance, creep resistance, and good flame retardancy, making it widely used in aerospace, electronics, and medical fields. Like most polymers, PEEK exhibits relatively low thermal and electrical conductivity. Its unique molecular structure contributes to its strong solvent resistance and allows for high processing temperatures. Melt blending is a common method for preparing thermally conductive composite materials, but it can lead to uneven filler dispersion in the matrix, agglomeration, interfacial defects, and significant interfacial thermal resistance, making it difficult to effectively improve the thermal and electrical conductivity of the composite material. Therefore, it is necessary to find suitable methods to improve its thermal and electrical conductivity and expand the application range of PEEK materials. Summary of the Invention

[0003] In view of this, the present invention proposes a method for preparing a fluorinated polyether ether ketone thermally conductive and electromagnetically shielding composite material to solve the above-mentioned technical problems.

[0004] The technical solution of this invention is implemented as follows:

[0005] A method for preparing a fluorinated polyetheretherketone (PEEK) thermally conductive and electromagnetically shielding composite material includes the following steps:

[0006] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0007] 4,4'-difluorobenzophenone, hexafluorobisphenol A, hydroquinone, catalyst and organic solvent were added sequentially, and a two-stage heating reaction was carried out. The reactants were washed and dried to obtain fluorinated polyether ether ketone powder.

[0008] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0009] (1) The carbon nanotube and graphene nanosheet composite filler are mixed in an organic solvent, stabilized, and then the fluorinated polyether ether ketone powder is added and ultrasonically dispersed to obtain a mixed dispersion.

[0010] (2) The mixed dispersion was placed in a poor solvent for deposition, and the deposit was washed and dried to obtain fluorinated polyether ether ketone composite powder;

[0011] (3) The fluorinated polyether ether ketone composite powder is melted and hot-pressed to obtain fluorinated polyether ether ketone composite sheet.

[0012] The present invention provides a fluorinated polyether ether ketone composite sheet prepared by combining fluorinated polyether ether ketone with carbon nanotubes and graphene nanosheets. This composite sheet not only has excellent thermal conductivity and electromagnetic shielding properties, but also the synthesis process of the fluorinated polyether ether ketone composite material is simple.

[0013] Furthermore, in step S1, the molar amount of hexafluorobisphenol A is 60%-100% of the total molar amount of hexafluorobisphenol A and hydroquinone. This invention synthesizes fluorinated polyether ether ketones with different degrees of fluorination by controlling the ratio of hexafluorobisphenol A and hydroquinone, thereby further optimizing the degree of fluorination of the fluorinated polyether ether ketone.

[0014] Furthermore, in step S1, the catalyst is one or a mixture of several of sodium carbonate, potassium carbonate, and cesium carbonate.

[0015] Furthermore, in step S1, the organic solvent is at least one of sulfolane and diphenyl sulfone.

[0016] Furthermore, in step S1, the first stage of the heating reaction is at a temperature of 135℃-145℃, with a reaction time of 1.5-2.5 hours; the second stage is at a temperature of 220℃-240℃, with a reaction time of 1.8-2.2 hours. This invention controls the first stage heating reaction conditions to better and more completely remove the water generated in the reaction; the preferred second stage heating reaction conditions better facilitate the synthesis of fluorinated polyether ether ketone through polymerization.

[0017] Furthermore, in step S2(1), the organic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

[0018] Furthermore, in step S2(1), the mass of the carbon nanotube is 20%-40% of the total mass of the carbon nanotube and graphene nanosheet. This invention regulates the ratio of carbon nanotubes to graphene nanosheets to optimize the contact area between the fillers.

[0019] Furthermore, in step S2(1), the mass of the composite filler is 10%-30% of the total mass of the fluorinated polyether ether ketone composite material. This invention controls the mass ratio of the carbon nanotube and graphene nanosheet composite filler, further regulating and optimizing the content of the composite filler.

[0020] Furthermore, in step S2(2), the undesirable solvent is a mixture of any two of water, ethanol, acetone, and isopropanol. The present invention preferably uses a mixed solution of two undesirable solvents, which better facilitates the precipitation of deposits through solvent exchange.

[0021] Furthermore, in step S2(3), the melting hot pressing temperature is 350℃-365℃ and the pressure is 35MPa-40MPa.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] I. The fluorinated polyether ether ketone composite material provided by this invention exhibits excellent thermal conductivity and electromagnetic shielding properties. Specifically, the introduction of fluorinated groups enhances the interfacial bonding between the filler and the polymer matrix, reducing phonon interfacial scattering. The carbon nanotube and graphene nanosheet composite filler constructs a complete thermal conductivity pathway, reducing the interfacial thermal resistance between the filler and the matrix, decreasing phonon interfacial scattering, and improving thermal conductivity.

[0024] Second, molecular-level solution mixing facilitates uniform dispersion of fillers and the formation of good thermal and electrical conduction pathways, providing channels for high-speed phonon transport and effectively improving the thermal and electrical conductivity of composite materials.

[0025] The fluorinated polyether ether ketone composite material provided by this invention can be used in military, automotive, energy or medical fields, expanding the application range of polyether ether ketone. Attached Figure Description

[0026] Figure 1 The infrared spectrum of the fluorinated polyether ether ketone in Example 2 is shown.

[0027] Figure 2 The image shows the DSC curve of the fluorinated polyether ether ketone in Example 2.

[0028] Figure 3 The thermogravimetric curves of the fluorinated polyether ether ketone composite material in Example 2 are shown.

[0029] Figure 4 The electromagnetic shielding curve is shown for the fluorinated polyether ether ketone composite material in Example 2. Detailed Implementation

[0030] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0031] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0032] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0033] Example 1

[0034] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0035] Under a nitrogen atmosphere, 0.015 mol of 4,4'-difluorobenzophenone, 0.015 mol of hexafluorobisphenol A, 0.018 mol of anhydrous potassium carbonate, and 30 mL of sulfolane were added sequentially to a 100 mL three-necked flask equipped with a stirrer, thermometer, and water separator. The mixture was mechanically stirred and heated to 140 °C for 2 h. After completely removing the water generated in the reaction, the temperature was raised to 230 °C and the reaction was continued for another 2 h. The product was poured into 500 mL of deionized water, cooled, pulverized, washed sequentially with hot methanol and deionized water, filtered, and vacuum dried at 120 °C for 12 h to obtain a white polyetheretherketone powder with 100% fluorination.

[0036] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0037] (1) 0.36g of carbon nanotubes (diameter 100-300nm, length 5-20μm) and 1.44g of graphene nanosheets (7-10mm) composite filler were dispersed in 100mL of N-methylpyrrolidone solvent and sonicated for 3h to obtain a relatively stable dispersion. 4.2g of polyether ether ketone with 100% fluorination was added to the dispersion and sonicated until completely dissolved to obtain a fluorinated polyether ether ketone composite material solution with 30wt% composite filler content and 100% fluorination.

[0038] (2) The fluorinated polyether ether ketone composite material solution with a composite filler content of 30wt% and a fluorination degree of 100% was added to 50mL of ethanol and 50mL of water for deposition until the deposit was precipitated. The deposit was washed with ethanol and water in turn and dried in a vacuum drying oven at 80℃ for 12h to obtain fluorinated polyether ether ketone composite material powder with a composite filler content of 30wt% and a fluorination degree of 100%.

[0039] (3) The fluorinated polyether ether ketone composite powder with a composite filler content of 30 wt% and a fluorination degree of 100% obtained in step (2) is spread into a mold with an inner diameter of 4×4 cm and placed in a molding press for pre-pressing at a pressure of 5 MPa and a temperature of 360°C for 10 min. Then, while keeping the temperature constant, the pressure is increased to 37.5 MPa for 15 min. Finally, the pressure is removed and cooled to room temperature to obtain a fluorinated polyether ether ketone composite sheet with a composite filler content of 30 wt% and a fluorination degree of 100%.

[0040] Example 2

[0041] The difference from Example 1 is that:

[0042] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0043] The amount of hexafluorobisphenol A added was 0.012 mol and hydroquinone was 0.003 mol, and a white polyetheretherketone powder with a fluorination degree of 80% was finally obtained.

[0044] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0045] By adding polyetheretherketone powder with a fluorination degree of 80%, a fluorinated polyetheretherketone composite sheet with a composite filler content of 30 wt% and a fluorination degree of 80% was finally obtained. Other processes were the same as in Example 1.

[0046] Example 3

[0047] The difference from Example 1 is that:

[0048] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0049] The amount of hexafluorobisphenol A added was 0.009 mol and hydroquinone was 0.006 mol, and a white polyether ether ketone powder with a fluorination degree of 60% was finally obtained.

[0050] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0051] By adding polyetheretherketone powder with a fluorination degree of 60%, a fluorinated polyetheretherketone composite sheet with a composite filler content of 30 wt% and a fluorination degree of 60% was finally obtained. Other processes were the same as in Example 1.

[0052] Example 4

[0053] The difference from Example 1 is that:

[0054] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0055] The amount of hexafluorobisphenol A added was 0.012 mol and hydroquinone was 0.003 mol, and a white polyetheretherketone powder with a fluorination degree of 80% was finally obtained.

[0056] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0057] The composite filler consists of 0.24g of carbon nanotubes (100-300nm in diameter and 5-20μm in length) and 0.96g of graphene nanosheets (7-10mm), along with 4.8g of polyetheretherketone powder with 80% fluorination, ultimately yielding a fluorinated polyetheretherketone composite sheet with a composite filler content of 20wt% and a fluorination degree of 80%. Other processes are consistent with Example 1.

[0058] Example 5

[0059] The difference from Example 1 is that:

[0060] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0061] The amount of hexafluorobisphenol A added was 0.012 mol and hydroquinone was 0.003 mol, and a white polyetheretherketone powder with a fluorination degree of 80% was finally obtained.

[0062] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0063] The composite filler consists of 0.12g of carbon nanotubes (100-300nm in diameter, 5-20μm in length) and 0.48g of graphene nanosheets (7-10mm), along with 5.4g of polyetheretherketone powder with 80% fluorination, ultimately yielding a fluorinated polyetheretherketone composite sheet with a composite filler content of 10wt% and a fluorination degree of 80%. Other processes are consistent with Example 1.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that:

[0066] S1. Synthesis method of soluble fluorinated polyether ether ketone:

[0067] The amount of hexafluorobisphenol A added was 0.012 mol and hydroquinone was 0.003 mol, and a white polyetheretherketone powder with a fluorination degree of 80% was finally obtained.

[0068] Synthesis method of S2, fluorinated polyether ether ketone composite material:

[0069] 6g of polyetheretherketone (PEEK) powder with an 80% fluorination degree was directly spread into a mold with an inner diameter of 4×4cm and placed in a molding machine for pre-compression at a pressure of 5MPa and a temperature of 360℃ for 10min. Then, while maintaining the temperature, the pressure was increased to 37.5MPa for 15min. Finally, the pressure was removed and the mixture was cooled to room temperature to obtain a fluorinated PEEK sheet with an 80% fluorination degree. Other processes were the same as in Example 1.

[0070] Comparative Example 2

[0071] 0.36 g of carbon nanotubes (diameter 100-300 nm, length 5-20 μm) and 1.44 g of graphene nanosheets (7-10 mm) were dispersed in 100 mL of N-methylpyrrolidone solvent and sonicated for 3 h to obtain a relatively stable dispersion. 4.2 g of pure polyether ether ketone was added to the dispersion and sonicated until completely dissolved to obtain a pure polyether ether ketone composite material solution with a composite filler content of 30 wt%.

[0072] The obtained pure polyether ether ketone composite material solution with a composite filler content of 30 wt% was added to 50 mL of ethanol and 50 mL of water for deposition until the precipitate was formed. The precipitate was washed with ethanol and water and dried in a vacuum drying oven at 80 °C for 12 h to obtain pure polyether ether ketone composite material powder with a composite filler content of 30 wt%.

[0073] The obtained pure polyether ether ketone composite powder with a composite filler content of 30 wt% was spread into a mold with an inner diameter of 4×4 cm and placed in a molding press for pre-compression at a pressure of 5 MPa and a temperature of 360℃ for 10 min. Then, while maintaining the temperature, the pressure was increased to 37.5 MPa for 15 min. Finally, the pressure was removed and the material was cooled to room temperature to obtain a pure polyether ether ketone composite sheet with a composite filler content of 30 wt%.

[0074] The thermal conductivity of the composite sheets prepared in the embodiments and comparative examples of the present invention was tested, and the specific results are shown in Table 1.

[0075] Table 1

[0076]

[0077] As shown in Table 1, the fluorinated polyether ether ketone composite material provided by the present invention has excellent thermal conductivity.

[0078] Figure 1 The infrared spectrum of the fluorinated polyether ether ketone in Example 2 is shown, with 1172 cm⁻¹ as an example. -1 The characteristic absorption peak of -CF3- is at 1244 cm⁻¹. -1 This is the absorption peak of the asymmetric stretching vibration of COC, at 10¹⁶ cm⁻¹. -1 The peak represents the symmetrical stretching vibration of COC, and is located between 3500 and 3200 cm⁻¹. -1 The absence of a -OH vibrational absorption peak indicates that fluorinated polyether ether ketone was successfully synthesized.

[0079] Figure 2 The DSC curve of the fluorinated polyether ether ketone in Example 2 shows that the polymer has only one glass transition temperature (Tg), indicating that the polymer is a terpolymer. The copolymer's Tg is 158°C, which is higher than that of polyether ether ketone (Tg = 143°C). This is because the introduced -CF3- is highly polar and has significant steric hindrance, hindering chain movement and thus increasing the glass transition temperature.

[0080] Figure 3 The thermogravimetric curve of the fluorinated polyether ether ketone composite material in Example 2 shows that the initial decomposition temperature of the fluorinated polyether ether ketone composite material is 519℃, indicating that the fluorinated polyether ether ketone composite material provided by the present invention has good thermal stability.

[0081] Figure 4 The electromagnetic shielding curve of the fluorinated polyether ether ketone composite material in Example 2 shows that the total electromagnetic shielding effectiveness of the composite material is 50.15 dB and the total shielding efficiency is 99.99%, indicating that the fluorinated polyether ether ketone composite material provided by the present invention has good electromagnetic shielding performance.

[0082] As can be seen from Table 1, the thermal conductivity of the fluorinated polyether ether ketone composite material with a fluorination degree of 80% synthesized in Comparative Example 1 decreased because carbon nanotubes and graphene nanosheets were not used as composite fillers.

[0083] As can be seen from Table 1, the thermal conductivity of the pure polyether ether ketone composite material with a composite filler content of 30 wt% synthesized in Comparative Example 2 decreased.

[0084] The fluorinated polyetheretherketone composite material provided by this invention exhibits excellent thermal conductivity and electromagnetic shielding properties. The introduction of fluorinated groups enhances the interfacial bonding between the filler and the polymer matrix, reducing phonon interfacial scattering. Synergistic carbon nanotubes and graphene nanosheets increase the contact area between the fillers, improving the thermal and electrical conductivity pathways.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a fluorinated polyetheretherketone (PEEK) thermally conductive and electromagnetically shielding composite material, characterized in that: Includes the following steps: S1. Synthesis method of soluble fluorinated polyether ether ketone: 4,4'-difluorobenzophenone, hexafluorobisphenol A, hydroquinone, catalyst and organic solvent were added sequentially, and a two-stage heating reaction was carried out. The reactants were washed and dried to obtain fluorinated polyether ether ketone powder. Synthesis method of S2, fluorinated polyether ether ketone composite material: (1) The carbon nanotube and graphene nanosheet composite filler are mixed in an organic solvent, stabilized, and then the fluorinated polyether ether ketone powder is added and ultrasonically dispersed to obtain a mixed dispersion. (2) The mixed dispersion was placed in a poor solvent for deposition, and the deposit was washed and dried to obtain fluorinated polyether ether ketone composite powder; (3) The fluorinated polyether ether ketone composite powder is melted and hot-pressed to obtain fluorinated polyether ether ketone composite sheet.

2. The preparation method of the fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S1, the molar amount of hexafluorobisphenol A is 60%-100% of the total molar amount of hexafluorobisphenol A and hydroquinone.

3. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S1, the catalyst is one or a mixture of several of sodium carbonate, potassium carbonate, and cesium carbonate.

4. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S1, the organic solvent is at least one of sulfolane and diphenyl sulfone.

5. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S1, the temperature of the first stage of the heating reaction is 135℃-145℃, and the reaction time is 1.5-2.5h; the temperature of the second stage of the reaction is 220℃-240℃, and the reaction time is 1.8-2.2h.

6. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S2(1), the organic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

7. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S2(1), the mass of the composite filler is 10%-30% of the total mass of the fluorinated polyether ether ketone composite material; wherein the mass of the carbon nanotube is 20%-40% of the total mass of the carbon nanotube and graphene nanosheet.

8. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S2(2), the undesirable solvent is a mixture of any two of water, ethanol, acetone and isopropanol.

9. The method for preparing a fluorinated polyetheretherketone thermally conductive and electromagnetically shielding composite material as described in claim 1, characterized in that: In step S2(3), the melting hot pressing temperature is 350℃-365℃ and the pressure is 35MPa-40MPa.

10. A fluorinated polyetheretherketone (PEEK) thermally conductive and electromagnetically shielding composite material, characterized in that: It is prepared by the preparation method according to any one of claims 1-9.

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