A wave-absorbing polyaryletherketone composite material and its preparation method

Abstract

The present invention relates to the technical field of functional materials, and specifically relates to a wave-absorbing polyaryletherketone composite material and a preparation method thereof, which include the following materials in weight percentages: at least 3% of an iron-containing alloy soft magnetic powder and at least 60% of polyaryletherketone; wherein the iron-containing alloy soft magnetic powder is introduced during the synthesis of the polyaryletherketone. Specifically, the air in the reaction kettle is first removed by a protective atmosphere. Under stirring and the protective atmosphere, the iron-containing alloy soft magnetic powder, difluorobenzophenone, and diphenol monomer are first subjected to a prepolymerization reaction in a reaction solvent under the action of a salt-forming agent, and then a polycondensation reaction is carried out, and the polyaryletherketone is precipitated and prepared; the iron-containing alloy soft magnetic powder is selected from one or more of an iron-silicon-aluminum alloy, FeSi alloy, FeCrNi alloy, FeNiMo alloy, FeNi alloy, and neodymium-iron-boron alloy; the composite material of the present invention has good wave-absorbing performance and does not cause secondary electromagnetic wave reflection pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and particularly relates to a wave-absorbing polyaryletherketone composite material and a preparation method thereof. Background Art

[0002] With the rapid development of electronic technology, electronic appliances and radio communications have been widely used. While electronic devices bring convenience to people's life, work and study, they also cause many adverse effects. Among them, the serious electromagnetic pollution problem has become another major public hazard after noise pollution, air pollution, water pollution and solid waste pollution.

[0003] At present, the methods to solve electromagnetic interference include distance protection and the use of electromagnetic shielding materials. Among them, distance protection is mainly because the greater the radiation distance of electromagnetic waves, the smaller the radiation intensity, but this is affected by the product space and layout; the most important means is still to use shielding materials that have absorption and reflection effects on electromagnetic waves. Electromagnetic shielding is to use the shielding body to absorb and reflect electromagnetic waves to prevent the electromagnetic waves radiated inside from leaking out of the internal area, or to prevent external radiation waves from entering the internal area, so as to protect a specific area from external electromagnetic wave interference.

[0004] Polyaryletherketone belongs to an insulating material and does not have electromagnetic shielding performance by itself without modification. Therefore, it is necessary to modify its electromagnetic shielding performance through certain technical means.

[0005] As described in the published polyaryletherketone with electromagnetic shielding performance such as patent CN117624827A, its shielding effectiveness is at least 28.2 dB and at most 112.3 dB. The formula contains highly conductive nickel powder. Due to impedance mismatch, its shielding mechanism is mainly to highly reflect electromagnetic waves to prevent radiation waves from entering the protected area; in addition, carbon fiber with good conductivity is used in the formula, and when the addition ratio exceeds a certain amount, it will also cause impedance mismatch and highly reflect the incident wave. Although the shielding effectiveness value of this patent is relatively high, the highly reflected electromagnetic waves will form a secondary pollution source and cause electromagnetic interference to other electronic devices in the surrounding environment. Another example is the published patent CN115339112A, which uses carbon series conductive fillers to prepare an electromagnetic shielding polyaryletherketone composite material with a shielding effectiveness greater than 45 dB, but 35 dB of it is caused by the high reflection of electromagnetic waves.

[0006] The currently developed electromagnetic shielding polyaryletherketone composite material has a high reflection effect on electromagnetic waves, and the generated highly reflected electromagnetic waves are likely to cause secondary electromagnetic pollution. Summary of the Invention

[0007] In order to reduce the secondary high reflection of composite materials to electromagnetic waves, a wave-absorbing polyaryletherketone composite material and a preparation method thereof are provided. In the present invention, an alloy soft magnetic powder containing iron is introduced in situ in polyaryletherketone, and the obtained composite material has good wave-absorbing performance and no secondary electromagnetic wave reflection pollution.

[0008] In order to achieve the above object, the present invention is realized through the following technical solutions:

[0009] A wave-absorbing polyaryletherketone composite material, comprising the following materials in weight percentages: at least 3% of an alloy soft magnetic powder containing iron, and at least 60% of polyaryletherketone; wherein the alloy soft magnetic powder containing iron is introduced during the synthesis of the polyaryletherketone.

[0010] Furthermore, the proportion of the alloy soft magnetic powder containing iron in the composite material is in the range of 5-20 wt%; preferably, the proportion of the alloy soft magnetic powder containing iron in the composite material is in the range of 5-15 wt%.

[0011] Furthermore, the iron content in the alloy soft magnetic powder containing iron is at least, and the powder particle size is less than 500 mesh.

[0012] Preferably, the alloy soft magnetic powder containing iron is selected from one or more of iron-silicon-aluminum alloy, FeSi alloy, FeCrNi alloy, FeNiMo alloy, FeNi alloy, neodymium iron boron alloy.

[0013] A preparation method of a wave-absorbing polyaryletherketone composite material, comprising the following steps:

[0014] First, use a protective atmosphere to remove the air in the reaction kettle. Under stirring and a protective atmosphere, pre-polymerize the alloy soft magnetic powder containing iron, difluorobenzophenone, and diphenol monomer in a reaction solvent under the action of a salt-forming agent, and then carry out polycondensation reaction, and precipitate to obtain the wave-absorbing polyaryletherketone composite material.

[0015] Furthermore, the reaction solvent is NMP, and the diphenol monomer is one or more of benzenediol, biphenyldiol, naphthalenediol, carbon-bridged diphenol, diphenone, ether diphenol, diphenol sulfone, fluorenediol, heterocyclic ring-containing diphenol compounds. For the specific types of diphenol monomers, reference can be made to CN116023248B;

[0016] The salt-forming agent is sodium carbonate and / or potassium carbonate, with a moisture content less than 0.2% and a purity greater than 99.9%.

[0017] Furthermore, the temperature of the pre-polymerization reaction is 120-150 °C, and the reaction time is 1-3 h; the temperature of the polycondensation reaction is 190-210 °C, and the reaction time is 4-8 h.

[0018] Further, after the polycondensation reaction is completed, the temperature of the polycondensation reaction is maintained, and a diphenol monomer is added to adjust the molecular weight for 0.5 - 1 h, and then a capping agent is added for capping for 0.5 - 1 h. Generally, the amount of the diphenol monomer added to adjust the molecular weight is 0.5 - 1% of the molar amount of the diphenol monomer before the start of the polycondensation reaction, and the addition amount of the capping agent is 0.5% of the molar amount of the difluorobenzophenone.

[0019] Further, precipitation is carried out by using a poor solvent such as water, absolute ethanol, anhydrous methanol, etc. to precipitate the product from the reacted system, and the product can be obtained by washing and drying.

[0020] Further, the dosage of the iron-containing alloy soft magnetic powder is 5.5 - 20% of the total weight of the difluorobenzophenone and the diphenol monomer;

[0021] The molar ratio of the difluorobenzophenone to the diphenol monomer is 1 - 1.05:1; the molar ratio of the salt-forming agent to the diphenol monomer is 1 - 1.2:1; the dosage of the reaction solvent is 2.5 to 3 times the total weight of the difluorobenzophenone and the diphenol monomer.

[0022] Beneficial technical effects:

[0023] In the present invention, a soft magnetic material and a monomer are used for in-situ polymerization to obtain a composite material. When electromagnetic waves pass through the composite material, the magnetic field in the composite material generates a magnetization effect, converting the energy of the electromagnetic waves into heat energy, resulting in the conversion and dissipation of the magnetic field energy, thereby reducing the reflection and propagation of electromagnetic waves and achieving the purpose of eliminating electromagnetic waves;

[0024] The iron-containing alloy soft magnetic / PEEK composite material prepared by the present invention has good electromagnetic wave absorption performance. It mainly absorbs harmful electromagnetic waves through the magnetic loss mechanism, and there is no secondary electromagnetic pollution caused by the reflection of electromagnetic waves;

[0025] In the present invention, a magnetic loss medium material such as an iron-containing alloy soft magnetic is dispersed in the PEEK resin at the front end of the synthesis, avoiding the problem of uneven dispersion in subsequent twin-screw extrusion blending processing, simplifying the production process flow, and reducing energy consumption waste. Description of the drawings

[0026] Figure 1 Absorption curves of composite materials with the same FSiAl alloy content (5.1 wt%) at different thicknesses;

[0027] Figure 2 Absorption curves of composite materials with the same FSiAl alloy content (9.3 wt%) at different thicknesses;

[0028] Figure 3Absorption curves of composites with the same FSiAl alloy content (12.7 wt%) at different thicknesses. Detailed implementation manners

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0030] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the said technologies and methods should be regarded as part of the specification. In all examples shown and discussed here, any specific value should be construed as merely exemplary, and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0031] The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards; if there are no corresponding national standards, they are carried out according to general standard requirements or general methods.

[0032] The following FeSiAl alloy used has an FeSiAl alloy composition of Fe-Si9.6-Al5.4 (containing 5.4 wt% aluminum, 9.6 wt% silicon, and the balance being Fe), and the particle size is between 60 and 200 mesh.

[0033] The FeSi alloy used has a composition of Fe-Si0.5 to 4, and the particle size is less than 200 mesh.

[0034] The neodymium iron boron alloy used generally has a neodymium content of 12 - 32 wt%, a boron content of 1 - 3 wt%, and an iron content of 60 - 68 wt%, and does not exceed 400 mesh.

[0035] The FeNi alloys used include FeNi36, FeNi47, and FeNi50; among them, the FeNi36 alloy composition is Fe-Ni36-Si0.1-Cr0.1-C0.01; the FeNi47 alloy composition is Fe-Ni47.5-Si0.1-Cr0.1-C0.01; the FeNi50 alloy composition is Fe-Ni50-Si0.1-Cr0.1-C0.01; and the particle size is less than 200 mesh.

[0036] The FeCrNi alloy used has a composition of Fe-Cr12-Ni1-C0.01, and the particle size is less than 200 mesh.

[0037] The FeNiMo alloy composition used is Fe-Ni79.8-Mo5.2-Si0.1-Cr0.1-C0.01, and the particle size is less than 200 mesh.

[0038] The following takes the aromatic nucleophilic polycondensation reaction of 4,4'-difluorobenzophenone and hydroquinone to prepare polyether ether ketone as an example. If other polyaryletherketone high molecular polymers with a structure similar to that of polyether ether ketone are needed, other monomers can be used, and the unit monomers recorded in CN116023248B can be referred to.

[0039] Examples 1 to 3

[0040] Under the protection of N2, first remove the air in the reaction kettle, and then according to the material dosages in Table 1 below, sequentially add FeSiAl alloy soft magnetic powder, NMP solvent, 4,4'-difluorobenzophenone, and sodium carbonate into a three-necked flask with mechanical stirring. While stirring, preheat to 100 °C. After stirring evenly, add hydroquinone, and first carry out a salt-forming prepolymerization reaction at 140 °C for 2 h, and then raise the temperature to 195 °C and react for 6 h; pour the reaction product into anhydrous ethanol, and the product will precipitate out. Wash the product with distilled water 6 times, and finally dry it under vacuum at 100 °C for 48 h to obtain FeSiAl / PEEK microwave absorbing composite material.

[0041] Blank control example

[0042] The preparation process of this example is the same as that of Example 1, the difference is that FeSiAl alloy soft magnetic powder is not introduced.

[0043] The material dosages of the blank control example and Examples 1 to 3 are shown in Table 1 below.

[0044] Table 1 Material dosages of Examples 1 - 3

[0045]

[0046] Example 4

[0047] This example is the in-situ polymerization of FeNi50 / PEEK microwave absorbing composite material. During the polymerization process, the dosages of NMP, fluoroketone, salt-forming agent, and hydroquinone are the same as those in Example 1. The difference is that FeNi50 alloy soft magnetic powder is used, and the proportion of FeNi50 in the FeNi50 / PEEK microwave absorbing composite material in this example is 5.1 wt%.

[0048] Example 5

[0049] This example is the in-situ polymerization of FeCrNi / PEEK microwave absorbing composite material. During the polymerization process, the dosages of NMP, fluoro ketone, salt-forming agent, and hydroquinone are the same as those in Example 1. The difference is that FeCrNi alloy soft magnetic powder is used, and the proportion of FeCrNi in the FeCrNi / PEEK microwave absorbing composite material in this example is 15 wt%.

[0050] Example 6

[0051] This example is the in-situ polymerization of FeNiMo / PEEK microwave absorbing composite material. During the polymerization process, the dosages of NMP, fluoro ketone, salt-forming agent, and hydroquinone are the same as those in Example 1. The difference is that FeNiMo alloy soft magnetic powder is used, and the proportion of FeNiMo in the FeNiMo / PEEK microwave absorbing composite material in this example is 15 wt%.

[0052] Comparative Example 1

[0053] In this example, PEEK and FeSiAl alloy are melt-blended and extruded into pellets, and then compression molding and injection molding are carried out respectively. The microwave absorbing properties of the compression-molded blend composite material are tested, and the mechanical properties of the injection-molded blend composite material are tested. The dosage of FeSiAl alloy accounts for 10 wt% of the blend composite material.

[0054] Test Example

[0055] 1. The microwave absorbing composite materials of Examples 1-3 are respectively compression-molded into samples with a thickness of 0.5 mm and 1.0 mm for microwave absorbing property testing. The microwave absorbing property is tested by the bow-tie method, and the results are shown in Figures 1 to 3 . It can be seen from Figures 1 to 3 that the reflectivity of the peak value of the characteristic absorption peak is less than -10 dB (corresponding to the absorption rate of electromagnetic waves at 90%); at the same time, in the case of the same content of FeSiAl, as the thickness of the material increases, the maximum absorption peak frequency gradually migrates to the low frequency; in addition, as the content of FeSiAl increases, the frequency of the maximum absorption peak gradually increases.

[0056] 2. The mechanical properties of the above examples are tested, and the test results are shown in Table 2.

[0057] Table 2 Mechanical Properties and Microwave Absorbing Properties

[0058]

[0059]

[0060] As can be seen from Table 2, the content of iron alloy soft magnetic powder in the composite materials of Examples 1-3 is in the range of 5-13 wt%, which has good mechanical strength and wave absorption performance. Comparative Example 1 prepared the composite material by the blending method. Due to the problem of uneven dispersion of the soft magnetic powder in the matrix resin, the mechanical properties and wave absorption performance are much worse than those of Example 2.

[0061] The present invention uses an iron-containing soft magnetic material and a monomer for in-situ polymerization to obtain an iron-containing alloy soft magnetic / PEEK composite material. When electromagnetic waves pass through the composite material, the magnetic field in the composite material undergoes a magnetization effect. Through the mechanism of magnetic loss, the energy of the electromagnetic waves is converted into heat energy, and harmful electromagnetic waves are absorbed, so that the absorbed energy is transformed and dissipated. Thus, the reflection and propagation of electromagnetic waves can be reduced, and the purpose of eliminating electromagnetic waves can be achieved. It has good electromagnetic wave absorption performance and does not cause secondary electromagnetic pollution caused by the reflection of electromagnetic waves. In the front end of the synthesis of the present invention, a magnetic loss medium material such as an iron-containing alloy soft magnetic is dispersed in the PEEK resin, avoiding the problem of uneven dispersion in the subsequent twin-screw extrusion blending process, simplifying the production process flow, and reducing the waste of energy consumption.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A wave-absorbing polyaryletherketone composite material, characterized in that, Comprising the following materials by weight percentage: the iron-containing alloy soft magnetic powder accounts for 5-15 wt%, and the polyaryletherketone is at least 60%; Wherein the iron-containing alloy soft magnetic powder is introduced during the synthesis of the polyaryletherketone, including the following steps: first, use a protective atmosphere to remove the air in the reaction kettle. Under stirring and a protective atmosphere, the iron-containing alloy soft magnetic powder, difluorobenzophenone, and diphenol monomer are first subjected to a prepolymerization reaction in a reaction solvent under the action of a salt-forming agent, and then a polycondensation reaction is carried out. The precipitated product is the wave-absorbing polyaryletherketone composite material; the diphenol monomer is hydroquinone; The temperature of the prepolymerization reaction is 120-150 °C, and the reaction time is 1-3 h; the temperature of the polycondensation reaction is 190-210 °C, and the reaction time is 4-8 h; The iron-containing alloy soft magnetic powder is selected from one or more of iron-silicon-aluminum alloy, FeSi alloy, FeCrNi alloy, FeNiMo alloy, FeNi alloy, and neodymium iron boron alloy; The FeSi alloy has a composition of Fe-Si 0.5-4, and the particle size is less than 200 mesh; For the iron-silicon-aluminum alloy, the FeSiAl alloy has a composition of Fe-Si 9.6-Al 5.4, and the particle size is between 60-200 mesh; For the neodymium iron boron alloy, the neodymium content is 12-32 wt%, the boron content is 1-3 wt%, and the iron content is 60-68 wt%, and the particle size does not exceed 400 mesh; The FeNi alloy is selected from one or more of FeNi36, FeNi47, and FeNi50; among them, the FeNi36 alloy has a composition of Fe-Ni 36-Si 0.1-Cr 0.1-C 0.01; the FeNi47 alloy has a composition of Fe-Ni 47.5-Si 0.1-Cr 0.1-C 0.01; the FeNi50 alloy has a composition of Fe-Ni 50-Si 0.1-Cr 0.1-C 0.01; the particle size is less than 200 mesh; The FeCrNi alloy has a composition of Fe-Cr 12-Ni 1-C 0.01, and the particle size is less than 200 mesh; The FeNiMo alloy has a composition of Fe-Ni 79.8-Mo 5.2-Si 0.1-Cr 0.1-C 0.01, and the particle size is less than 200 mesh.

2. The microwave absorbing polyaryletherketone composite material according to claim 1, wherein The reaction solvent is NMP; The salt-forming agent is sodium carbonate and / or potassium carbonate, with a moisture content of less than 0.2% and a purity of greater than 99.9%.

3. The microwave absorbing polyaryletherketone composite material according to claim 1, wherein After the polycondensation reaction is completed, maintain the temperature of the polycondensation reaction, add the diphenol monomer to adjust the molecular weight for 0.5-1 h, and then add a capping agent to cap for 0.5-1 h.

4. An electromagnetic wave absorbing polyaryletherketone composite material according to claim 1, characterized in that, Precipitation is carried out by using a poor solvent to precipitate the product from the reaction system, and the product is washed and then dried.

5. An electromagnetic wave absorbing polyaryletherketone composite material according to claim 1, characterized in that, The dosage of the iron-containing alloy soft magnetic powder is 5.5-20% of the total weight of the difluorobenzophenone and the diphenol monomer; the molar ratio of the difluorobenzophenone to the diphenol monomer is 1-1.05:1; the molar ratio of the salt-forming agent to the diphenol monomer is 1-1.2:1; the dosage of the reaction solvent is 2.5 to 3 times the total weight of the difluorobenzophenone and the diphenol monomer.

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