A high thermal and electrical conductivity polyetheretherketone-based composite material based on reversible oxidation and its preparation method
By converting polyetheretherketone (PEEK) into soluble PEEK-1,3-dithiopentane and carrying out a catalytic reaction and hot pressing, the problem of poor electrical conductivity of PEEK materials was solved, realizing the preparation of high thermal and electrical conductivity composite materials and expanding its application fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2023-09-12
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional polyetheretherketone (PEEK) materials have extremely poor electrical conductivity, making it difficult to achieve uniform dispersion and continuous conductive and thermal conduction pathways, which limits their application in the fields of heat conduction, heat dissipation, and electromagnetic interference.
A reversible conversion strategy was adopted to convert polyetheretherketone into soluble polyetheretherketone-1,3-dithiopentane, and uniform dispersion of the filler was achieved by N-methyl-2-pyrrolidone solution. Subsequently, a catalytic reaction and melt hot pressing were carried out to prepare a composite material with high thermal and electrical conductivity.
This method achieves good dispersion of fillers in the matrix, breaks through the technical barriers of traditional melt processing, and improves the electrical and thermal conductivity of composite materials.
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Figure CN117165029B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials, and in particular to a high thermal and electrical conductivity polyether ether ketone-based composite material based on reversible oxidation and its preparation method. Background Technology
[0002] With the development of fifth-generation mobile communication technology (5G), electronic devices are evolving towards miniaturization, thinning, high speed, and high integration. This leads to continuously increasing power consumption and difficulties in heat dissipation, severely limiting the development of next-generation electronic components. Simultaneously, electromagnetic radiation pollution is becoming increasingly prominent, reducing the lifespan of sensitive electronic components and posing a threat to human health. Traditional thermally conductive (TC) and electromagnetic interference (EMI) materials, such as aluminum and copper foil, are no longer sufficient to meet the demands of modern communications, smart electronic devices, automobiles, and consumer electronics due to their high density and poor corrosion resistance. Polymer materials, with their advantages of lightweight, chemical corrosion resistance, impact resistance, thermal fatigue resistance, and ease of processing, are widely used in industry, microelectronics, energy, and aerospace. However, because polymers are poor conductors of electricity and heat, their generally low thermal conductivity, electrical conductivity, and electromagnetic shielding effectiveness limit their application in heat conduction, heat dissipation, and electromagnetic interference. Therefore, there is an urgent need to develop lightweight, high-performance thermally and electrically conductive composite materials.
[0003] Polyetheretherketone (PEEK), a semi-crystalline polymer, belongs to the category of special polymer materials. It possesses advantages such as high heat resistance, radiation resistance, chemical resistance, impact resistance, creep resistance, good flame retardancy, and excellent electrical properties, making it widely used in high-speed rail systems, low-energy and new energy vehicles, efficient transportation technologies and equipment, aerospace, electronics, information technology, and defense. However, as a polymer material, PEEK's structural characteristics result in extremely poor electrical conductivity: PEEK molecules are composed of numerous atoms interconnected by covalent bonds, while unbonded electrons are bound to individual atoms, unable to form effective charge carriers. Therefore, it has extremely poor conductivity and lacks electromagnetic shielding properties.
[0004] With the development of modern society, materials face complex and diverse environments during application, and single polyetheretherketone (PEEK) resins can no longer meet the diverse application requirements. To expand the application fields of PEEK and fully leverage its advantages as a special engineering plastic, in-depth research on PEEK composite materials has become a hot topic both domestically and internationally.
[0005] Therefore, introducing fillers into the PEEK resin matrix to prepare polyether ether ketone-based composite materials can give full play to the advantages of PEEK as a special engineering plastic, while giving the material high thermal conductivity, electromagnetic shielding and other excellent properties, which has important application significance.
[0006] In the preparation of polyetheretherketone (PEEK) composites, since PEEK is almost insoluble in all solvents, traditional blending methods (such as melt processing) are often used. However, it is difficult to achieve uniform dispersion of fillers to achieve good electrical and thermal conductivity in the composites. This is because the melt viscosity of traditional melt-blended polymers is high, and the thermally conductive fillers are poorly dispersed in the polymer system, making it difficult to construct continuous electrical and thermal conductivity pathways.
[0007] To address the dispersion issue of thermally and electrically conductive fillers in polyetheretherketone (PEEK) matrices, maximize the electrical and thermal conductivity of the fillers, and prepare PEEK-based composite materials with superior performance, this invention proposes a chemically reversible conversion strategy to achieve the interconversion between PEEK and soluble PEEK-1,3-dithiopentane. The NMP solution of soluble PEEK-1,3-dithiopentane is then used to better disperse the composite filler, thus expanding the processing pathways and application areas of PEEK composite materials. Summary of the Invention
[0008] In view of this, the present invention proposes a high thermal and electrical conductivity polyether ether ketone-based composite material based on reversible oxidation and its preparation method, thereby overcoming the above-mentioned problems.
[0009] The technical solution of this invention is implemented as follows:
[0010] A method for preparing a high thermal and electrical conductivity polyether ether ketone-based composite material based on reversible oxidation includes the following steps: (1) adding polyether ether ketone to dichloromethane, then adding trifluoroacetic acid under nitrogen protection, stirring to dissolve it, adding 1,2-ethanedithiol, then adding boron trifluoride ethyl ether, after reaction, discharging, washing, drying, to obtain polyether ether ketone-1,3-dithiopentane;
[0011] (2) Take polyetheretherketone-1,3-dithiopentane, dissolve it in N-methyl-2-pyrrolidone, stir to dissolve, add filler, sonicate first and then stir to obtain a polymer solution containing filler.
[0012] (3) The polymer solution containing filler was discharged into ethanol, stirred, and after solvent exchange, vacuum filtered and heated to dry to obtain a polyether ether ketone-1,3-dithiopentane-based composite material.
[0013] (4) Take the polyetheretherketone-1,3-dithiopentane composite material, transfer it to an acetonitrile solution containing N-bromosuccinimide (NBS) for catalytic reaction, and then transfer it to an ethanol or methanol bath for conversion reaction;
[0014] (5) The polyether ether ketone composite material obtained by solution blending is placed in a mold, preheated in a hot press, and then melt-pressed to obtain a polyether ether ketone composite sheet.
[0015] This invention provides a reversible chemical conversion method based on polyetheretherketone (PEEK) to soluble polyetheretherketone-1,3-dithiolane (PEEK-dithiolane), which realizes the conversion of the semi-crystalline polymer polyetheretherketone, which is insoluble in most solvents, into a soluble disulfide ring derivative. Through reversible modification, the semi-crystalline PEEK is transformed into an amorphous material with greater solubility and processability. Furthermore, the soluble polyetheretherketone-dithiolane (PEEK-dithiolane) is converted back into polyetheretherketone through catalytic-ketalization.
[0016] Furthermore, in step (1), the polyetheretherketone has a mesh size of 50 to 200 mesh, preferably 200 mesh;
[0017] The molar ratio of polyetheretherketone, 1,2-ethylenedithiol, and boron trifluoride ethyl ether is 1:2 to 5:2 to 2.5, preferably 1:1:2, 1:2:2, or 1:5:2.
[0018] The ratio of polyetheretherketone, dichloromethane, and trifluoroacetic acid is 1 mol: 5-6 L: 1-1.5 L.
[0019] The molar amount of polyetheretherketone added is calculated based on the ketone carbonyl group;
[0020] The reaction is carried out at room temperature for 20–28 hours, and the drying temperature is 75–85°C.
[0021] Furthermore, in step (2), the mass-to-volume ratio (g / ml) of the polyetheretherketone-1,3-dithiopentane to N-methyl-2-pyrrolidone is 14:1000-1100.
[0022] Furthermore, in step (2), the amount of filler added is 10 to 30% of the total mass of polyetheretherketone-1,3-dithiopentane and filler, preferably 30%.
[0023] Furthermore, in step (2), the filler is composed of graphene and carbon nanotubes, and the mass ratio of graphene to carbon nanotubes is 2-8:8-2, preferably 8:2.
[0024] Furthermore, in step (2), after adding the filler, ultrasonication is performed for 5-8 hours, followed by stirring for 20-28 hours.
[0025] Furthermore, in step (3), the volume ratio of the polymer solution containing filler to ethanol is 1000-1200:4500-5500, the stirring time is 45-55h, and the heating and drying temperature is 75-85℃.
[0026] Furthermore, in step (4), the molar ratio of polyetheretherketone-1,3-dithiopentane to N-bromosuccinimide in the polyetheretherketone-1,3-dithiopentane composite material is 1:1 to 5, preferably 1:5;
[0027] The solvent for the N-bromosuccinimide solution is acetonitrile, ethanol, or methanol, and the mass-to-volume ratio of N-bromosuccinimide to solvent in the acetonitrile solution of N-bromosuccinimide is 40-50:500-600 (g / ml).
[0028] The catalytic reaction time is 12-36 hours, preferably 36 hours.
[0029] Furthermore, in step (5), the preheating temperature is 350-400℃, the preheating time is 20-30min, and the hot-pressing process is: hot-pressing is carried out under a pressure of 45-55MPa for 10-20min.
[0030] A highly thermally and electrically conductive polyether ether ketone-based composite material based on reversible oxidation is prepared by any one of the preparation methods described in this invention.
[0031] Compared with the prior art, the beneficial effects of the present invention are:
[0032] (1) This invention utilizes the chemical reversible reaction between insoluble semi-crystalline polyether ether ketone and soluble polyether ether ketone-1,3-dithiopentane to achieve solution processing of polyether ether ketone composite materials, which makes the filler have better dispersibility in the matrix, breaks through the technical barrier of traditional melt processing of polyether ether ketone-based composite materials, and achieves better electrical and thermal conductivity.
[0033] (2) The method provided by this invention achieves better compatibility and dispersibility between polyether ether ketone (PEEK) and fillers, which is beneficial to the thermal conductivity of the composite material. This invention utilizes the solubility of the precursor to achieve solution processing of PEEK composite materials through a reversible chemical conversion method. The prepared soluble precursor can be dissolved in non-acidic solvents, such as N-methyl-2-pyrrolidone (NMP), which expands the solution processing methods of composite materials and increases the dispersibility of fillers in soluble precursors. Attached Figure Description
[0034] Figure 1 : Process flow diagram of the high thermal and electrical conductivity polyether ether ketone composite material prepared by the present invention.
[0035] Figure 2 Thermogravimetric analysis of the polyetheretherketone-1,3-dithiopentane prepared in this invention.
[0036] Figure 3Infrared image of the polyetheretherketone-1,3-dithiopentane prepared in this invention.
[0037] Figure 4 NMR spectrum of the polyetheretherketone-1,3-dithiopentane prepared in this invention.
[0038] Figure 5 The present invention converts polyetheretherketone-1,3-dithiopentane into polyetheretherketone, and the NMR spectrum of the converted product is shown.
[0039] Figure 6 The present invention converts polyetheretherketone-1,3-dithiopentane into polyetheretherketone, and the infrared image of the converted product is shown.
[0040] Figure 7 The present invention describes the thermogravimetric analysis of the conversion of polyetheretherketone-1,3-dithiopentane into polyetheretherketone.
[0041] Figure 8 , Figure 9 The thermal conductivity of polyetheretherketone composite materials prepared by different ratios of graphene and carbon nanotubes in this invention is shown in the figure, wherein the total amount of composite filler is 30%.
[0042] Figure 10 , Figure 11 The thermal conductivity diagram of the polyether ether ketone composite material prepared in this invention shows that when the mass ratio of the composite filler graphene to carbon nanotubes is 8:2, the total amount of the composite filler is 10%, 20%, and 30%, respectively.
[0043] Figure 12 The conductivity of the polyether ether ketone composite material is shown in the figure when the mass ratio of graphene to carbon nanotubes in the composite filler is 8:2 and the total amount of composite filler is 10%, 20%, and 30%, respectively.
[0044] Figure 13 , Figure 14 The thermal conductivity diagram of the polyetheretherketone composite sheet prepared in this invention is shown in the figure. Comparative Example 1: dry mixing, Comparative Example 2: wet mixing, and Example 1: solution blending.
[0045] Figure 15 The conductivity diagram of the polyetheretherketone composite sheet prepared in this invention is shown in the figure. Among them, Comparative Example 1: dry mixing, Comparative Example 2: wet mixing, and Example 1: solution blending. Detailed Implementation
[0046] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.
[0047] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.
[0048] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.
[0049] Example 1
[0050] 1. Preparation of soluble polyetheretherketone 1,3-dithiopentane (chemically reversible)
[0051] Polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) of different mesh sizes (50, 100, 200 mesh) was added to a three-necked flask containing 500 mL of dichloromethane and uniformly dispersed under the action of a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring was continued for 1 h to allow the PEEK to fully dissolve and form a yellow viscous solution. First, 1,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, and the system showed no obvious change. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the viscosity of the solution decreased, and the solution immediately turned into a clear orange solution. With stirring, the color of the solution gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol or methanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol or methanol. The white product was washed repeatedly under reflux with ethanol or methanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyether ether ketone-1,3-dithiopentane, with a yield of 98%.
[0052]
[0053] First, weigh 44.5 g (0.25 mol) of N-bromosuccinimide (NBS) and dissolve it completely in 500 ml of acetonitrile. Then, add 18.2 g (0.05 mol) of polyetheretherketone-1,3-dithiopentane and stir at room temperature for 36 hours. Afterward, perform vacuum filtration and wash repeatedly with ethanol or methanol. Then, transfer the solution to an ethanol or methanol bath for further soaking to convert polyetheretherketone-1,3-dithiopentane into polyetheretherketone (denoted as RPEEK).
[0054]
[0055] 2. Preparation of high thermal and electrical conductivity polyetheretherketone composite materials based on the chemically reversible regeneration and conversion of polyetheretherketone.
[0056] 2.1 First, weigh 14g of polyetheretherketone-1,3-dithiopentane and dissolve it in 1000mL of N-methyl-2-pyrrolidone (NMP). Stir thoroughly until completely dissolved. Add 6g of filler (graphene:carbon nanotube mass ratio of 8:2, 6:4, 4:6, 2:8 respectively). Sonicate for 6h and then stir for 24h to achieve uniform dispersion of filler in polymer solution.
[0057] 2.2 Subsequently, the polymer solution containing the filler was discharged into 5000 mL of ethanol, stirred for 48 h, and after sufficient solvent exchange, vacuum filtered and dried at 80 °C to obtain the polyether ether ketone-1,3-dithiopentane-based composite material.
[0058] 2.3 Subsequently, 26g of the polyetheretherketone-1,3-dithiopentane composite material was weighed and transferred to 500mL of acetonitrile containing 44.5g of N-bromosuccinimide (NBS) for catalytic reaction. Then, the composite material was transferred to an ethanol or methanol bath for conversion reaction to achieve the chemical conversion between polyetheretherketone-1,3-dithiopentane and polyetheretherketone.
[0059] 2.4 The polyetheretherketone composite material obtained by solution blending was placed into a 40mm×40mm×0.5mm mold and placed in a hot press. It was first preheated at 380℃ for 25 minutes, and then held at 50MPa for 15 minutes for melt hot pressing to obtain a series of polyetheretherketone composite sheets with a composite filler content of 30wt% and different proportions of graphene and carbon nanotubes. The preparation flow chart is shown below. Figure 1 As shown.
[0060] Study Example 1 - Investigating the optimal amounts of polyetheretherketone, 1,2-ethanedithiol, and boron trifluoride ethyl ether during the preparation of polyetheretherketone-1,3-dithiopentane.
[0061] 1. Polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 1,2-ethanedithiol (4.4 mL, 0.1 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0062] 2. Polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 1,2-ethylenedithiol (8.8 mL, 0.2 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0063] 3. Polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 1,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0064] The results showed that the polyetheretherketone-1,3-dithiopentane prepared had the best solubility when the molar ratio of PEEK to 1,2-ethylenedithiol and boron trifluoride diethyl ether was 1:5:2.
[0065] Study Example 2 – This study investigated the effect of different mesh sizes of polyetheretherketone (PEEK) on the preparation of polyetheretherketone-1,3-dithiopentane when the amounts of PEEK, 1,2-ethylenedithiol, and boron trifluoride ether were the same.
[0066] 1. 28.8 g of 50-mesh polyetheretherketone (PEEK, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 2,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0067] 2. 100-mesh polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and uniformly dispersed under stirring. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 1,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0068] 3. 28.8 g of 200-mesh polyetheretherketone (PEEK, 0.1 mol ketone carbonyl content) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 hour to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 2,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 hours, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain a white solid product, polyetheretherketone-1,3-dithiopentane. The thermal weight loss, infrared spectroscopy, and NMR characteristics of the prepared polyetheretherketone-1,3-dithiopentane are as follows: Figure 2 , Figure 3 , Figure 4 As shown.
[0069] The results showed that when the amounts of polyetheretherketone, 1,2-ethylenedithiol, and boron trifluoride ether were the same, the 200-mesh ether had the best dissolution effect in trifluoroacetic acid / dichloromethane, and the prepared polyetheretherketone-1,3-dithiopentane had the best effect.
[0070] Study Example 3 – Investigating the effects of using different NBS and catalytic times on chemically reversible reactions.
[0071] 1. Weigh 8.9 g (0.05 mol) of N-bromosuccinimide (NBS), dissolve it completely in 500 mL of acetonitrile, then add 18.2 g (0.05 mol) of polyetheretherketone-1,3-dithiopentane, stir at room temperature for 12 hours, then vacuum filter, and wash repeatedly with ethanol, then transfer to an ethanol bath to continue soaking to convert polyetheretherketone-1,3-dithiopentane into polyetheretherketone (denoted as RPEEK).
[0072] 2. Weigh 17.8 g (0.1 mol) of N-bromosuccinimide (NBS), dissolve it completely in 500 mL of acetonitrile, then add 18.2 g (0.05 mol) of polyetheretherketone-1,3-dithiopentane, stir at room temperature for 24 hours, then vacuum filter, and wash repeatedly with ethanol, then transfer to an ethanol bath to continue soaking to convert polyetheretherketone-1,3-dithiopentane into polyetheretherketone (denoted as RPEEK).
[0073] 3. Weigh 44.5 g (0.25 mol) of N-bromosuccinimide (NBS) and dissolve it completely in 500 mL of acetonitrile. Then add 18.2 g (0.05 mol) of polyetheretherketone-1,3-dithiopentane and stir at room temperature for 36 hours. Afterward, perform vacuum filtration and repeatedly wash with ethanol. Transfer the solution to an ethanol bath for further soaking to convert polyetheretherketone-1,3-dithiopentane into polyetheretherketone (denoted as RPEEK). The thermogravimetric analysis, infrared spectroscopy, and NMR of the prepared polyetheretherketone-1,3-dithiopentane are as follows: Figure 5 , Figure 6 , Figure 7 As shown.
[0074] The results showed that the optimal catalytic effect was achieved when the molar ratio of NBS to polyetheretherketone-1,3-dithiopentane was 5:1, with a catalytic time of 36 hours. The NMR spectra of the converted material were as follows: Figure 5 As shown, the NMR spectrum of the sample is basically consistent with that of pure polyether ether ketone, indicating that the reversible reaction was successful.
[0075] Study Example 4 - Investigating the effect of adding different amounts of filler to composite materials on their thermal and electrical conductivity.
[0076] 1. 28.8 g of 200-mesh polyetheretherketone (PEEK, 0.1 mol ketone carbonyl content) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 2,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0077] 14 g of polyetheretherketone-1,3-dithiopentane was weighed and dissolved in 1000 mL of N-methyl-2-pyrrolidone (NMP). The solution was stirred thoroughly until completely dissolved. 6 g of composite filler (graphene:carbon nanotube mass ratios of 8:2, 6:4, 4:6, and 2:8) was added. The mixture was sonicated for 6 h and then stirred for 24 h to achieve uniform dispersion of the filler in the polymer solution. The polymer solution containing the filler was then discharged into 5000 mL of ethanol and stirred for 48 h to allow for complete solvent exchange. Afterward, the solution was vacuum filtered and dried at 80 °C to obtain the polyetheretherketone-1,3-dithiopentane composite material. Subsequently, 26g of the polyetheretherketone-1,3-dithiopentane composite material was weighed and transferred to 500mL of acetonitrile containing 44.5g of N-bromosuccinimide (NBS) for catalytic reaction. The mixture was then transferred to an ethanol bath to achieve the chemical conversion between polyetheretherketone-1,3-dithiopentane and polyetheretherketone. The resulting polyetheretherketone composite material was placed in a 40mm×40mm×0.5mm mold and preheated at 380℃ for 25min in a hot press. Then, it was melt-pressed under 50MPa pressure for 15min to obtain a series of polyetheretherketone composite sheets with a composite filler content of 30wt% and different proportions of graphene and carbon nanotubes.
[0078] 2. 200-mesh polyetheretherketone (PEEK, 28.8 g, ketone carbonyl content 0.1 mol) was added to a three-necked flask containing 500 mL of dichloromethane and uniformly dispersed under stirring. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 h to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 1,2-ethanedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 h, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0079] 16 g of polyetheretherketone-1,3-dithiopentane was weighed and dissolved in 1000 mL of N-methyl-2-pyrrolidone (NMP). The solution was stirred thoroughly until completely dissolved. 4 g of composite filler (graphene:carbon nanotube mass ratios of 8:2, 6:4, 4:6, and 2:8) was added. The mixture was sonicated for 6 h and then stirred for 24 h to achieve uniform dispersion of the filler in the polymer solution. The polymer solution containing the filler was then discharged into 5000 mL of ethanol and stirred for 48 h to allow for complete solvent exchange. Afterward, the solution was vacuum filtered and dried at 80 °C to obtain the polyetheretherketone-1,3-dithiopentane composite material. Subsequently, 26g of the polyetheretherketone-1,3-dithiopentane composite material was weighed and sequentially transferred to 500mL of acetonitrile containing 44.5g of N-bromosuccinimide (NBS) for catalytic reaction. The mixture was then transferred to an ethanol bath to achieve the chemical conversion between polyetheretherketone-1,3-dithiopentane and polyetheretherketone. The resulting polyetheretherketone composite material was placed in a 40mm×40mm×0.5mm mold and preheated at 380℃ for 25min in a hot press. Then, it was melt-pressed under 50MPa pressure for 15min to obtain a series of polyetheretherketone composite sheets with a composite filler content of 20wt% and different proportions of graphene and carbon nanotubes.
[0080] 3. 28.8 g of 200-mesh polyetheretherketone (PEEK, 0.1 mol ketone carbonyl content) was added to a three-necked flask containing 500 mL of dichloromethane and dispersed uniformly with a stirrer. Then, under nitrogen (N2) protection, 100 mL of trifluoroacetic acid was added, and stirring continued for 1 hour to allow the PEEK to fully dissolve, forming a yellow viscous solution. First, 2,2-ethylenedithiol (22 mL, 0.5 mol) was added to the solution, with no significant change in the system. Then, boron trifluoride diethyl ether (25 mL, 0.2 mol) was added, and the solution viscosity decreased, immediately turning into a clear orange solution. With stirring, the solution color gradually deepened to a deep red. After reacting at room temperature for 24 hours, the product was discharged into 4000 mL of ethanol. The precipitated solid was light red and gradually turned into a white product with prolonged immersion in ethanol. The white product was washed repeatedly under reflux with ethanol until no obvious thiol odor was detected, and then dried at 80°C to obtain the white solid product polyetheretherketone-1,3-dithiopentane.
[0081] 18 g of polyetheretherketone-1,3-dithiopentane was weighed and dissolved in 1000 mL of N-methyl-2-pyrrolidone (NMP). The solution was stirred thoroughly until completely dissolved. 2 g of composite filler (graphene:carbon nanotube mass ratios of 8:2, 6:4, 4:6, and 2:8) was added. The mixture was sonicated for 6 h and then stirred for 24 h to achieve uniform dispersion of the filler in the polymer solution. The polymer solution containing the filler was then discharged into 5000 mL of ethanol and stirred for 48 h to allow for complete solvent exchange. Afterward, the solution was vacuum filtered and dried at 80 °C to obtain the polyetheretherketone-1,3-dithiopentane composite material. Subsequently, 26g of the polyetheretherketone-1,3-dithiopentane composite material was weighed and transferred to 500mL of acetonitrile containing 44.5g of N-bromosuccinimide (NBS) for catalytic reaction. The mixture was then transferred to an ethanol bath to achieve the chemical conversion between polyetheretherketone-1,3-dithiopentane and polyetheretherketone. The resulting polyetheretherketone composite material was placed in a 40mm×40mm×0.5mm mold and preheated at 380℃ for 25min in a hot press. Then, it was melt-pressed under 50MPa pressure for 15min to obtain a series of polyetheretherketone composite sheets with a composite filler content of 10wt% and different proportions of graphene and carbon nanotubes.
[0082] Experimental results showed that the polyetheretherketone-1,3-dithiopentane prepared from 200-mesh polyetheretherketone had the best effect, the composite material with 30% filler content had the best thermal and electrical conductivity, and the composite filler graphene and carbon nanotubes had the best synergistic effect when the mass ratio was 8:2.
[0083] Experimental data such as Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 As shown.
[0084] Analysis of experimental results:
[0085] Figure 8 For a filler content of 30%, composite materials were prepared by solution blending graphene and carbon nanotubes in different mass ratios. The out-of-plane thermal conductivity was tested, and it was found that the highest out-of-plane thermal conductivity of 3.38 W / m² was achieved when the mass ratio of graphene to carbon nanotubes was 8:2. -1 K -1 .
[0086] Figure 9 For a filler content of 30%, composite materials were prepared by solution blending graphene and carbon nanotubes in different mass ratios. The in-plane thermal conductivity was tested, and it was found that the highest in-plane thermal conductivity of 7.56 W / m² was achieved when the mass ratio of graphene to carbon nanotubes was 8:2. -1 K -1 .
[0087] Figure 10 The out-of-plane thermal conductivity of the composite material was compared with that of different filler contents of 10%, 20%, and 30%. The results showed that the out-of-plane thermal conductivity of the composite material gradually increased with the increase of filler content.
[0088] Figure 11 The in-plane thermal conductivity of the composite material was compared with that of different filler contents of 10%, 20%, and 30%. The results showed that the in-plane thermal conductivity of the composite material gradually increased with the increase of filler content.
[0089] Figure 12 The electrical conductivity of the composite material was compared with that of different filler contents of 10%, 20%, and 30%. The results showed that the electrical conductivity of the composite material gradually increased with the increase of filler content.
[0090] Comparative Example 1. 14g of 200-mesh pure polyetheretherketone (PEEK) and 6g of composite filler (graphene:carbon nanotube mass ratio of 8:2) were placed in a high-speed mixer and mixed at 3000rpm for 60s to obtain a dry-mixed powder. The powder was placed in a 40mm×40mm×0.5mm mold and preheated in a hot press at 380℃ for 25min, followed by holding at 50MPa pressure for 15min for melt hot pressing to obtain a PEEK composite sheet with a composite filler content of 30wt%. Its thermal and electrical conductivity were tested.
[0091] Comparative Example 2: 14g of 200-mesh pure polyetheretherketone (PEEK) and 6g of composite filler (graphene:carbon nanotube mass ratio of 8:2) were dispersed in 1000ml of ethanol. The mixture was first sonicated for 6 hours, then stirred for 24 hours, vacuum filtered, and dried at 80℃ to obtain a wet-mixed powder. The powder was placed in a 40mm×40mm×0.5mm mold and preheated in a hot press at 380℃ for 25 minutes, followed by holding at 50MPa pressure for 15 minutes to obtain a PEEK composite sheet with a composite filler content of 30wt%. Its thermal and electrical conductivity were tested.
[0092] Comparison of thermal and electrical conductivity between Comparative Examples 1-2 and Example 1 of the present invention (solution blending) is as follows: Figure 13 , Figure 14 , Figure 15 As shown.
[0093] The results show that the thermal and electrical conductivity of the solution-blended composite material prepared using the present invention is significantly improved compared with the composite materials prepared by wet blending and dry blending.
[0094] Figure 13When the filler content is 30%, the thermal conductivity of the composite materials prepared by different methods is significantly different. The out-of-plane thermal conductivity is as follows: the out-of-plane thermal conductivity of the composite material prepared by solution blending is greater than that of the wet-blended composite material in Comparative Example 2, while the out-of-plane thermal conductivity of the wet-blended composite material is greater than that of the dry-blended composite material in Comparative Example 1.
[0095] Figure 14 When the filler content is 30%, the thermal conductivity of the composite materials prepared by different methods is significantly different. The in-plane thermal conductivity is as follows: the in-plane thermal conductivity of the composite material prepared by solution blending is greater than that of the wet-blended composite material in Comparative Example 2, while the in-plane thermal conductivity of the wet-blended composite material is greater than that of the dry-blended composite material in Comparative Example 1.
[0096] Figure 15 When the filler content is 30%, the electrical conductivity of the composite materials prepared by different methods is significantly different. Specifically, the electrical conductivity of the composite material prepared by solution blending is greater than that of the wet-blended composite material in Comparative Example 2, while the electrical conductivity of the wet-blended composite material is greater than that of the dry-blended composite material in Comparative Example 1.
[0097] 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 reversibly reversible high thermal and electrical conductivity polyetheretherketone-based composite material, characterized in that, Includes the following steps: (1) Add polyether ether ketone to dichloromethane, then add trifluoroacetic acid under nitrogen protection, stir to dissolve, add 1,2-ethylenedithiol, then add boron trifluoride ether, after reaction, discharge, wash, dry, and obtain polyether ether ketone-1,3-dithiopentane. (2) Take polyetheretherketone-1,3-dithiopentane, dissolve it in N-methyl-2-pyrrolidone, stir to dissolve, add filler, sonicate first and then stir to obtain a polymer solution containing filler; (3) The polymer solution containing filler was discharged into ethanol, stirred, and after solvent exchange, vacuum filtered and heated to dry to obtain a polyether ether ketone-1,3-dithiopentane-based composite material. (4) Take the polyetheretherketone-1,3-dithiopentane composite material, transfer it to an acetonitrile solution containing N-bromosuccinimide for catalytic reaction, and then transfer it to an ethanol or methanol bath for conversion reaction; (5) The polyether ether ketone composite material obtained by solution blending is placed in a mold, preheated in a hot press, and then melt-pressed to obtain the polyether ether ketone composite material. In step (2), the amount of filler added is 30% of the total mass of polyetheretherketone-1,3-dithiopentane and filler; In step (2), the filler is composed of graphene and carbon nanotubes, and the mass ratio of graphene to carbon nanotubes is 2~8:8~2; In step (5), the preheating temperature is 350~400℃ and the preheating time is 20~30min. The hot-pressing process is: hot-pressing is carried out under a pressure of 45~55MPa for 10~20min.
2. The preparation method according to claim 1, characterized in that, In step (1), the polyetheretherketone has a mesh size of 50 to 200 mesh; The molar ratio of polyetheretherketone, 1,2-ethylenedithiol, and boron trifluoride ethyl ether is 1:2~5:2~2.5; The ratio of polyetheretherketone, dichloromethane, and trifluoroacetic acid is 1 mol: 5~6 L: 1~1.5 L; The molar amount of polyetheretherketone added is calculated based on the ketone carbonyl group; The reaction is carried out at room temperature for 20-28 hours, and the drying temperature is 75-85°C.
3. The preparation method according to claim 1, characterized in that, In step (2), the mass-to-volume ratio of the polyetheretherketone-1,3-dithiopentane to N-methyl-2-pyrrolidone is 14:1000~1100.
4. The preparation method according to claim 1, characterized in that, In step (2), after adding the filler, sonicate for 5-8 hours and then stir for 20-28 hours.
5. The preparation method according to claim 1, characterized in that, In step (3), the volume ratio of the polymer solution containing filler to ethanol is 1000~1200:4500-5500, the stirring time is 45~55h, and the heating and drying temperature is 75~85℃.
6. The preparation method according to claim 1, characterized in that, In step (4), the molar ratio of polyetheretherketone-1,3-dithiopentane to N-bromosuccinimide in the polyetheretherketone-1,3-dithiopentane composite material is 1:1~5. The mass-to-volume ratio of N-bromosuccinimide to solvent in the acetonitrile solution of the N-bromosuccinimide is 40~50:500~600 (g / ml). The catalytic reaction time is 12-36 hours.
7. A high thermal and electrical conductivity polyetheretherketone-based composite material based on reversible oxidation, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.