A low-dielectric, lightweight, high-temperature-resistant polyaryletherketone composite material and its preparation method

Abstract

The present invention relates to the technical field of composite materials, and in particular to a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material and a preparation method thereof. The method comprises the following steps: weighing raw materials including sulfonated PEEK fine powder, hollow microspheres pretreated by alkali immersion, and polyaryletherketone fine powder; premixing the raw materials in a heat-insulated manner and then performing segmented heat-insulated compression molding to obtain the low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material; the present invention improves the fluidity of the composite by compounding the pretreated hollow microspheres, sulfonated PEEK, and a polyaryletherketone matrix, and effectively prevents the migration and precipitation of the hollow microspheres through segmented temperature increase compression molding, thereby solving the problem of phase separation of the composite and achieving uniform dispersion of the hollow microspheres in the matrix, thereby obtaining a composite material with low dielectric constant, light weight, and high-temperature aging resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material and a preparation method thereof. Background Art

[0002] Polyaryletherketone (PAEK), a high-performance thermoplastic polymer, exhibits excellent high-temperature aging resistance, chemical stability, and superior mechanical properties, making it a promising material for a wide range of applications in aerospace, electronics, automotive, and other fields. However, the application of PAEK in high-tech fields is limited, primarily due to its high dielectric constant.

[0003] In the field of intelligent driving, radar sensors are core components, and their performance directly impacts the safety and reliability of intelligent driving. Most radar sensors are installed in the engine compartment, which means they must operate in a high-temperature, thermal environment. In this environment, radar sensors require a high-temperature resistant cover to protect them from sunlight and heat. However, this cover must not only withstand high-temperature aging but also meet the stringent requirements for radar wave transmission.

[0004] Radomes have extremely high requirements for radar wave transmittance and attenuation. Conventional modified plastics can slow signal transmission, increase signal delay, and significantly reduce signal loss during radar wave transmission, thus impacting radar sensor performance. This has limited the application of PAEK materials in radomes. To address this issue, researchers have begun exploring polyetheretherketone (PEEK) composites, aiming to achieve low dielectric constant, low dielectric loss, high transmittance, and high-temperature aging resistance. Summary of the Invention

[0005] To achieve low dielectric constant, high transmittance, and high-temperature aging resistance, the present invention provides a low-dielectric, lightweight, and high-temperature resistant poly(aryletherketone) composite material and its preparation method. The present invention combines pretreated hollow microspheres, sulfonated PEEK, and a poly(aryletherketone) matrix to improve the fluidity of the composite. Furthermore, through staged heating and molding, the migration and precipitation of the hollow microspheres are effectively prevented, solving the phase separation problem of the composite while achieving uniform dispersion of the hollow microspheres in the matrix. The result is a composite material with low dielectric constant, light weight, and high-temperature aging resistance.

[0006] In order to achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material comprises the following steps:

[0008] Weigh the raw materials according to weight: 5-15 parts of sulfonated PEEK fine powder, 10-20 parts of hollow microspheres pretreated by alkali leaching, and 65-85 parts of polyaryletherketone fine powder;

[0009] The raw materials are pre-mixed evenly under heat preservation and then compression molded to obtain a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material;

[0010] The compression molding is divided into five sections of heating, heat preservation and pressure maintenance, each section of temperature and pressure maintenance is 5-10MPa, each section of temperature maintenance is 10-15min, and the heating rate is 3-5℃ / min:

[0011] The first section is heated to 350-360°C, the second section is heated to 361-370°C, the third section is heated to 371-380°C, the fourth section is heated to 381-390°C, and the fifth section is heated to 391-400°C.

[0012] Furthermore, the hollow microspheres are selected from hollow glass microspheres and / or hollow ceramic microspheres, and the average particle size of the combination of the two does not exceed 60 μm, and the bulk density does not exceed 0.6 g / cm 3 , compressive strength is at least 30MPa.

[0013] Furthermore, the hollow microspheres are selected from a combination of hollow glass microspheres and hollow ceramic microspheres, and the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 2-5:1, such as the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 4:1, or 5:1, or 5:2.

[0014] Furthermore, the alkaline leaching pretreatment process is: using a potassium hydroxide solution or a sodium hydroxide solution with a molar concentration of 1-5M to immerse the hollow microspheres at a constant temperature of 50-100°C, stirring while immersing, with a stirring rate of 60-120rpm, and a immersion time of 1-3h.

[0015] Furthermore, the average particle size of the sulfonated PEEK fine powder is less than 120 μm; and the melt index of the sulfonated PEEK fine powder at 400° C. and a load of 2.16 kg is 30-40 g / 10 min.

[0016] Furthermore, the sulfonated PEEK fine powder is obtained by placing the PEEK fine powder in concentrated sulfuric acid and ultrasonically stirring it for 3-5 hours, wherein the ultrasonic stirring is carried out under heating conditions of 80-120° C. and the ultrasonic power is 20 Hz.

[0017] Furthermore, the average particle size of the polyaryletherketone fine powder is less than 120 μm; and the melt index of the polyaryletherketone fine powder at 400° C. and a load of 2.16 kg is 25-40 g / 10 min.

[0018] Furthermore, the polyaryletherketone fine powder is selected from one or more of polyetheretherketone (PEEK), polyetherketone (PEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK) and polyetherketoneetherketoneketone (PEKEKK).

[0019] Furthermore, the premix is mixed using a low-speed mixer with a mixing rate lower than 350 rpm, a mixing time of 30-60 min, and a mixing temperature of 100-200°C.

[0020] Another aspect of the present invention provides a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material obtained by the above-mentioned preparation method.

[0021] Beneficial technical effects:

[0022] The present invention uses alkali treatment to increase the active groups on the surface of the hollow microspheres, thereby increasing their oxygen content. After mixing with sulfonated PEEK fine powder, the sulfonated PEEK has holes on its surface, which, on the one hand, provide anchoring points for a portion of the microspheres, thereby evenly dispersing the filler. On the other hand, the sulfonated PEEK interacts with the hollow microspheres, which are rich in hydroxyl groups on their surfaces, to improve the compatibility of the polyaryletherketone matrix and the microsphere filler. The sulfonated PEEK acts as a bridge between the matrix and the filler, thereby making the polyaryletherketone matrix and the filler more tightly fixed. In addition, the sulfonated PEEK and alkali-treated hollow microspheres can improve the fluidity of the matrix after compounding.

[0023] The present invention, under the premise of ensuring stable mechanical properties, utilizes hollow microbeads impregnated with alkali solution and sulfonated PEEK fine powder to compound, and fully mixes the treated hollow microbeads, sulfonated PEEK fine powder and untreated polyaryletherketone fine powder through a mixer, thereby greatly improving the fluidity of the material. The invention also adopts a staged heating method for molding, which can effectively prevent the precipitation of low-density hollow glass microbeads or hollow ceramic microbeads, solve the phase separation problem of the composite material, and achieve uniform dispersion of the hollow microbeads in the matrix, so that the obtained composite material has low dielectric properties and high-temperature aging resistance. The hollow structure of the hollow microbeads gives the composite material a micro-foaming effect, low density and high lightweight degree. The composite material is applied to a radar detection system. Due to its advantages of low density, low dielectric constant and high temperature resistance, it can allow high-frequency radar waves to pass through unimpeded, thereby ensuring efficient wave propagation, reducing energy loss and improving the detection performance and precision performance of the system. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. Technology and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and methods should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0026] In the following examples, the experimental methods without specific conditions are generally measured according to national standards; if there is no corresponding national standard, the general standard requirements or general methods are used.

[0027] Example 1

[0028] A method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material comprises the following steps:

[0029] S1. Alkali immersion pretreatment of hollow microspheres: using 1M KOH solution to constantly soak the hollow microspheres at 60°C for 60 minutes, adding a rotor to stir at a stirring rate of 150 rpm, and removing them from the water after soaking and drying them at 60°C. The hollow microspheres are a combination of hollow glass microspheres and hollow ceramic microspheres, and the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 4:1. At this mass ratio, the average particle size of the mixture of the two is 40-60 μm and the bulk density is 0.3-0.6 g / cm 3 The compressive strength of hollow glass microspheres is over 60MPa, and the compressive strength of hollow ceramic microspheres is 40MPa.

[0030] Preparation of sulfonated PEEK fine powder: PEEK fine powder (200 mesh) was placed in concentrated sulfuric acid (98wt%) and ultrasonically stirred at 80°C with an ultrasonic power of 20 Hz. The reaction was stopped after 4 hours. After cooling to room temperature, the powder was washed with water until neutral and vacuum dried at 240°C for 10 hours to obtain sulfonated PEEK fine powder. The melt index of the powder was measured to be 30 g / 10 min at 400°C and a load of 2.16 kg.

[0031] S2. Weigh the raw materials: 50 g of sulfonated PEEK fine powder, 300 g of pretreated hollow microspheres, and 650 g of 200-mesh PEEK fine powder; premix the above raw materials at 200 rpm and 100°C for 30 min, perform a melt index test after mixing, and the melt index (400°C, 2.16 kg) is 38 g / 10 min, and then perform compression molding, wherein the compression molding is divided into five sections of heating, heat preservation, and pressure maintenance, each section has a temperature and pressure maintenance of 5 MPa, each section has a temperature maintenance of 10 min, and a heating rate of 5°C / min: the first section is heated to 360°C, the second section is heated to 370°C, the third section is heated to 380°C, the fourth section is heated to 390°C, and the fifth section is heated to 400°C. After observing the pressure drop in real time, the pressure is replenished in time. After the mold temperature is reached, the pressure is repeatedly released multiple times, the staged heating is completed, and the mold is demolded after natural cooling to room temperature to obtain a low-dielectric, lightweight, and high-temperature resistant polyaryletherketone composite material.

[0032] Example 2

[0033] A method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material comprises the following steps:

[0034] S1. Alkali immersion pretreatment of hollow microspheres: using 2M KOH solution to constantly soak the hollow microspheres at 80°C for 90 minutes, adding a rotor to stir at a stirring rate of 150 rpm, and removing them from the water after soaking and drying them at 80°C. The hollow microspheres are a combination of hollow glass microspheres and hollow ceramic microspheres, and the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 5:1. At this mass ratio, the average particle size of the mixture of the two is 40-60 μm and the bulk density is 0.3-0.6 g / cm 3 The compressive strength of hollow glass microspheres is over 60MPa, and the compressive strength of hollow ceramic microspheres is 40MPa.

[0035] Preparation of sulfonated PEEK fine powder: PEEK fine powder (300 mesh) was placed in concentrated sulfuric acid (98wt%) and ultrasonically stirred at 100°C with an ultrasonic power of 20 Hz. The reaction was stopped after 4 hours. After cooling to room temperature, the powder was washed with water until neutral and vacuum dried at 240°C for 10 hours to obtain sulfonated PEEK fine powder. The melt index of the powder was measured to be 35 g / 10 min at 400°C and a load of 2.16 kg.

[0036] S2. Weigh the raw materials: 200 g of sulfonated PEEK fine powder, 350 g of pretreated hollow microspheres, and 450 g of 300-mesh PEEK fine powder; premix the above raw materials at 250 rpm and a temperature of 120°C for 45 min, perform a melt index test after mixing, and perform compression molding with a melt index (400°C, 2.16 kg) of 42 g / 10 min, wherein the compression molding is divided into five sections of heating, heat preservation, and pressure maintenance, each section has a temperature and pressure maintenance of 8 MPa, each section has a temperature maintenance of 15 min, and a heating rate of 4°C / min: the first section is heated to 365°C, the second section is heated to 375°C, the third section is heated to 385°C, the fourth section is heated to 390°C, and the fifth section is heated to 395°C. After observing the pressure drop in real time, the pressure is replenished in time. After the mold temperature is reached, the pressure is repeatedly released multiple times, the staged heating is completed, and the mold is demolded after natural cooling to room temperature to obtain a low-dielectric, lightweight, and high-temperature resistant polyaryletherketone composite material.

[0037] Example 3

[0038] A method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material comprises the following steps:

[0039] S1. Alkali immersion pretreatment of hollow microspheres: using 3M KOH solution to soak the hollow microspheres at a constant temperature of 100°C for 120 minutes, adding a rotor to stir at a stirring rate of 200 rpm, and removing them from the water after soaking and drying them at 100°C. The hollow microspheres are a combination of hollow glass microspheres and hollow ceramic microspheres, and the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 5:2. At this mass ratio, the average particle size of the mixture of the two is 40-60 μm and the bulk density is 0.3-0.6 g / cm 3 The compressive strength of hollow glass microspheres is over 60MPa, and the compressive strength of hollow ceramic microspheres is 40MPa.

[0040] Preparation of sulfonated PEEK fine powder: PEEK fine powder (400 mesh) was placed in concentrated sulfuric acid (98 wt%) and ultrasonically stirred at 120°C with an ultrasonic power of 20 Hz. The reaction was stopped after 4 hours. After cooling to room temperature, the powder was washed with water until neutral and vacuum dried at 240°C for 10 hours to obtain sulfonated PEEK fine powder. The melt index of the powder was measured to be 40 g / 10 min at 400°C and a load of 2.16 kg.

[0041] S2. Weigh the raw materials: 150 g of sulfonated PEEK fine powder, 300 g of pretreated hollow microspheres, and 650 g of 300-mesh PEEK fine powder; premix the above raw materials at 300 rpm and 140°C for 60 min, perform a melt index test after mixing, and perform compression molding with a melt index (400°C, 2.16 kg) of 45 g / 10 min, wherein the compression molding is divided into five sections of heating, heat preservation, and pressure maintenance, each section has a temperature and pressure maintenance of 5 MPa, each section has a temperature maintenance of 10 min, and a heating rate of 5°C / min: the first section is heated to 355°C, the second section is heated to 365°C, the third section is heated to 375°C, the fourth section is heated to 385°C, and the fifth section is heated to 395°C. Observe the pressure drop in real time and replenish the pressure in time. After the mold temperature is reached, the pressure is repeatedly released multiple times. After the staged heating is completed, the mold is demolded after natural cooling to room temperature to obtain a low-dielectric, lightweight, and high-temperature resistant polyaryletherketone composite material.

[0042] Example 4

[0043] The preparation process and formula of this case are the same as those of Example 2, except that the hollow microspheres are only hollow glass microspheres.

[0044] Example 5

[0045] The preparation process and formula of this case are the same as those of Example 2, except that the hollow microspheres are only hollow ceramic microspheres.

[0046] Comparative Example 1

[0047] This case is a composite material of 900 g of PEEK fine powder and 100 g of sulfonated PEEK fine powder. Other operations are the same as those in Example 1.

[0048] Comparative Example 2

[0049] In this case, the hollow microbeads were not pretreated with alkali solution, and other operations were the same as in Example 1.

[0050] Comparative Example 3

[0051] In this case, 150g of hollow microspheres were pretreated with 1.5g of silane coupling agent KH560 and 3.0g of titanate coupling agent (wet or dry treatment is possible, but wet treatment was chosen in this case). Other operations were the same as in Example 1. The cost of treating hollow microspheres with coupling agents is 3-5 times higher than that of alkaline etching, and is therefore relatively high.

[0052] Comparative Example 4

[0053] In this case, sulfonated PEEK fine powder was not used, and other operations were the same as in Example 1.

[0054] Comparative Example 5

[0055] This case adopts a five-stage heating, heat preservation and pressure holding compression molding method. The temperature is directly raised to 400°C at a heating rate of 10°C / min, the pressure is maintained at 5MPa, and the holding time is 40min. Other operations are the same as Example 1.

[0056] The above cases were subjected to performance testing, and the test results are shown in Table 1 below.

[0057] Table 1 Performance of each case

[0058]

[0059] As can be seen from the above table, the combination of hollow glass microspheres and hollow ceramic microspheres has a beneficial effect on reducing the density of the composite and improving the melt index, so that the composite has a micro-foaming effect, low density, and high lightweight. Combined with the segmented temperature rising molding, it effectively prevents the precipitation of low-density hollow glass microspheres or hollow ceramic microspheres, solves the phase separation problem of the composite material, and achieves uniform dispersion of the hollow microspheres in the matrix, so that the obtained composite has lower dielectric properties and high temperature aging resistance.

[0060] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a low-dielectric, lightweight, high-temperature-resistant polyaryletherketone composite material, characterized in that: The steps include: Weigh the raw materials according to weight: 5-15 parts of sulfonated PEEK fine powder, 10-20 parts of hollow microspheres pretreated by alkali leaching, and 65-85 parts of polyaryletherketone fine powder; The sulfonated PEEK fine powder is obtained by placing the PEEK fine powder in concentrated sulfuric acid and ultrasonically stirring it for 3-5 hours, wherein the ultrasonic stirring is carried out under heating conditions of 80-120° C. and the ultrasonic power is 20 Hz; Premixing the raw materials evenly and then performing compression molding to obtain a low-dielectric, lightweight, and high-temperature resistant polyaryletherketone composite material; The compression molding is divided into five sections of heating, heat preservation and pressure maintenance, each section of temperature and pressure maintenance is 5-10MPa, each section of temperature maintenance is 10-15min, and the heating rate is 3-5℃ / min: The first section is heated to 350-360°C, the second section is heated to 361-370°C, the third section is heated to 371-380°C, the fourth section is heated to 381-390°C, and the fifth section is heated to 391-400°C.

2. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 1, characterized in that: The hollow microspheres are selected from hollow glass microspheres and / or hollow ceramic microspheres, with an average particle size of no more than 60 μm and a bulk density of no more than 0.6 g / cm 3 , compressive strength is at least 30MPa.

3. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 2, characterized in that: The hollow microspheres are selected from a combination of hollow glass microspheres and hollow ceramic microspheres, and the mass ratio of the hollow glass microspheres to the hollow ceramic microspheres is 2-5:

1.

4. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 1, characterized in that: The alkaline leaching pretreatment process is: using a potassium hydroxide solution or a sodium hydroxide solution with a molar concentration of 1-5M to immerse the hollow microspheres at a constant temperature of 50-100° C., stirring while immersing, with a stirring rate of 60-120 rpm, and a immersion time of 1-3 hours.

5. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 1, characterized in that: The average particle size of the sulfonated PEEK fine powder is less than 120 μm; the melt index of the sulfonated PEEK fine powder at 400° C. and a load of 2.16 kg is 30-40 g / 10 min.

6. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 1, characterized in that: The average particle size of the polyaryletherketone fine powder is less than 120 μm; the melt index of the polyaryletherketone fine powder at 400° C. and a load of 2.16 kg is 25-40 g / 10 min.

7. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 6, characterized in that: The polyaryletherketone fine powder is selected from one or more of polyetheretherketone, polyetherketone, polyetherketoneketone, polyetheretherketoneketone and polyetherketoneetherketoneketone.

8. The method for preparing a low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material according to claim 1, characterized in that: The premix is mixed by a low-speed mixer with a mixing rate lower than 350 rpm, a mixing time of 30-60 min, and a mixing temperature of 100-200°C.

9. The low-dielectric, lightweight, and high-temperature-resistant polyaryletherketone composite material obtained by the preparation method according to claim 1.

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