Polyvinyl fluoride / graphene fluoride composite and method for molding the same

Abstract

A polyfluoroethylene / fluorinated graphene composite material and a forming method thereof, wherein the forming method of the polyfluoroethylene / fluorinated graphene composite material comprises: uniformly mixing fluorinated graphene powder and polytetrafluoroethylene powder to obtain polytetrafluoroethylene / fluorinated graphene composite powder; pressing the obtained polytetrafluoroethylene / fluorinated graphene composite powder through a flat die without limitation in four directions to obtain a preformed composite material; and further pressing the obtained preformed composite material in a closed die to obtain a polyfluoroethylene / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss at a high working frequency (GHz). The polyfluoroethylene / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss has excellent mechanical properties; and the addition of a small amount of fluorinated graphene not only effectively reduces the dielectric loss of polytetrafluoroethylene, but also effectively improves the mechanical properties of polytetrafluoroethylene.

Description

Technical Field

[0001] This invention relates to the field of low dielectric composite materials and their preparation technology, specifically to a polyvinyl fluoride / fluorinated graphene composite material and its molding method. Background Technology

[0002] The development of high-frequency, high-speed communication can effectively solve the problems of insufficient spectrum, transmission rate, and transmission capacity in wireless communication, playing a vital role in social development. However, with the rapid increase in the operating frequency of electromagnetic waves used in wireless communication, the requirements for the dielectric properties of the dielectric materials used are also becoming increasingly stringent. With a significant increase in frequency, the transmission loss of electromagnetic wave signals through dielectric materials increases significantly, thus affecting the effective transmission of communication signals. This transmission loss is related to the frequency (f) of the electromagnetic wave and the square root of the dielectric constant of the material. and dielectric loss factor (D f The dielectric loss of materials is directly proportional to the frequency of electromagnetic waves [Huangfu Mengge, Li Yidan, Zhang Yan, Wu Hao, Zhi Xinxin, Wu Xiao, Liu Jingang, Insulating Materials 2020, 53(8), 9]. Therefore, the continuous increase in electromagnetic wave frequency will inevitably lead to a significant increase in the dielectric loss of materials. Therefore, it is necessary to reduce the dielectric loss of materials. k Or D f This is to suppress the transmission loss that occurs when electromagnetic waves pass through materials. However, the D of commonly used dielectric materials currently in use... k The difference is usually small, typically in the range of 2 to 4, so only the material's D is reduced. k It cannot significantly suppress the transmission loss of electromagnetic waves; while the D of dielectric materials f Usually in 10 -2 ~10 -4 The variation is within a certain order of magnitude, with a large range of change; therefore, it can be mitigated by significantly reducing D. f Achieving a significant reduction in electromagnetic wave transmission loss is crucial. Therefore, developing materials with ultra-low dielectric constants and ultra-low dielectric losses is of great significance to meet the demands of the rapid development of high-frequency and high-speed communication technologies.

[0003] Polytetrafluoroethylene (PTFE), widely recognized as the polymer with the lowest dielectric loss, holds great promise for applications in high-frequency, high-speed communications. However, the development of PTFE materials currently faces two major challenges. One is the poor mechanical properties of PTFE. Current methods for reinforcing and modifying PTFE, while improving mechanical properties, inevitably compromise its ultra-low dielectric constant and ultra-low dielectric loss. For example, combining PTFE with spherical silica powder can effectively improve the mechanical properties of the composite material, resulting in a PTFE composite with a dielectric constant and dielectric loss factor of 3.2 and 0.002 at 5 GHz (patent CN106928599A). Combining PTFE with fiberglass cloth can effectively improve the dimensional stability of the composite material, and the prepared PTFE / fiberglass composite material has a dielectric constant and dielectric loss factor of 2.195 and 0.00075 at 10 GHz (patent CN113386418A). The other challenge is the lack of further methods to reduce the dielectric constant (D) of PTFE. f While there are relatively mature methods for reducing the dielectric constant of polymers, such as introducing pores, there is still no effective method for reducing the dielectric loss of polymers, which is even more difficult for polymers such as PTFE, which inherently have low dielectric loss. For the rapidly developing high-frequency and high-speed communication technologies, how to prepare polymer-based materials with lower dielectric loss than PTFE is not only of great practical significance but also presents a significant challenge. Summary of the Invention

[0004] Based on this, the present invention provides a polyvinyl fluoride / fluorinated graphene composite material and its molding method to solve the technical problem that the prior art has not achieved good results in reducing the dielectric loss of polymers.

[0005] To achieve the above objectives, the present invention provides a polytetrafluoroethylene / fluorinated graphene composite material, which is composed of polytetrafluoroethylene and fluorinated graphene, and has a dielectric constant Dk of 1.9 to 2.2 and a dielectric loss factor Df of 0.0001 to 0.00015 at 10 GHz.

[0006] As a further preferred embodiment of the present invention, the fluorine-carbon molar ratio of the fluorinated graphene is 0.8 to 1.1, and the oxygen-carbon molar ratio of the fluorinated graphene is 0.01 to 0.1.

[0007] As a further preferred embodiment of the present invention, the mass of the fluorinated graphene is 0.01% to 5.00 wt% of the mass of polytetrafluoroethylene.

[0008] As a further preferred embodiment of the present invention, the mass of the fluorinated graphene is 0.01% to 3.00 wt% of the mass of polytetrafluoroethylene.

[0009] As a further preferred technical solution of the present invention, the polytetrafluoroethylene / fluorinated graphene composite material is obtained by molding polytetrafluoroethylene and fluorinated graphene by compression molding, and is in the form of sheets.

[0010] According to another aspect of the present invention, the present invention also provides a method for molding the polyvinyl fluoride / fluorinated graphene composite material according to any one of the above claims, comprising the following steps:

[0011] 1) Fluorinated graphene powder and polytetrafluoroethylene powder are mixed evenly to obtain polytetrafluoroethylene / fluorinated graphene composite powder;

[0012] 2) Press the polytetrafluoroethylene / fluorinated graphene composite powder obtained in step 1) through a flat mold with unrestricted sides to obtain a pre-formed composite material.

[0013] 3) The preformed composite material obtained in step 2) is further pressed in a closed mold to obtain a polyvinyl fluoride / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss at high operating frequency (GHz).

[0014] As a further preferred technical solution of the present invention, in step 1), the particle size range of the fluorinated graphene powder and the polytetrafluoroethylene powder is 1 to 100 micrometers.

[0015] As a further preferred technical solution of the present invention, in step 1), the particle size range of the fluorinated graphene powder and the polytetrafluoroethylene powder is 20-50 micrometers.

[0016] As a further preferred technical solution of the present invention, the molding process conditions in steps 2) and 3) are: pressure of 30-200 MPa, molding temperature of 25-200°C, and molding time of 10-200 minutes.

[0017] As a further preferred technical solution of the present invention, the molding process conditions in steps 2) and 3) are: pressure of 50-100 MPa, molding temperature of 25-100°C, and molding time of 10-50 minutes.

[0018] The polyvinyl fluoride / fluorinated graphene composite material and its molding method of the present invention, by adopting the above technical solution, can achieve the following beneficial effects:

[0019] 1) The polytetrafluoroethylene / fluorinated graphene composite material provided by the present invention utilizes two-dimensional nanomaterial fluorinated graphene and polytetrafluoroethylene for simple blending and molding. It is easy to operate, low in cost, and has low requirements for equipment and process conditions. It is easier to achieve industrial production under existing conditions, and provides a new technical solution and new idea for reducing the dielectric loss of polytetrafluoroethylene.

[0020] 2) The ultra-low dielectric constant and ultra-low dielectric loss polytetrafluoroethylene / fluorinated graphene composite material provided by this invention can achieve a dielectric constant of 2.12 and a dielectric loss factor of 0.00012 at 10 GHz. Its dielectric loss factor is significantly reduced compared to pure PTFE (0.00021), and its ultra-low dielectric loss factor of 0.00012 is the lowest known value among polymer-based materials. This enables it to meet the requirements of high-frequency and high-speed communication technology for ultra-low dielectric constant and ultra-low dielectric loss performance of dielectric materials, which is conducive to promoting the application of polytetrafluoroethylene materials in high-frequency and high-speed communication technology.

[0021] 3) The polytetrafluoroethylene / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss provided by the present invention not only effectively reduces the dielectric loss of polytetrafluoroethylene due to the addition of a small amount of fluorinated graphene, but also effectively improves the mechanical properties of polytetrafluoroethylene, while also having excellent flexibility. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 The mechanical property test diagram of the polytetrafluoroethylene / fluorinated graphene composite material of the present invention is shown. Specifically, it is a comparison diagram of the polytetrafluoroethylene / fluorinated graphene composite material sample with a mass ratio of fluorinated graphene to polytetrafluoroethylene of 0.5wt% before and after bending.

[0024] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Terms such as "upper," "lower," "left," "right," "middle," and "one" used in the preferred embodiments are merely for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0026] Through a combination of computer molecular simulations and experimental studies, it was found that the regular two-dimensional structure and highly oriented CF bonds of fluorinated graphene give it a very low dielectric constant and dielectric loss. At the same time, fluorinated graphene (FG) can greatly promote the high orientation of PTFE molecular chains at the interface of the composite material of PTFE and fluorinated graphene, and significantly reduce the deflection polarization of CF bonds on PTFE under an external field, thereby greatly reducing dielectric loss.

[0027] This application employs fluorinated graphene to composite modify polytetrafluoroethylene (PTFE). Through raw material structure screening and optimization of various process parameters, the mechanical properties of PTFE are improved while its Do at high frequencies (GHz) is significantly reduced. k and D f The dielectric constant D of the polytetrafluoroethylene / fluorinated graphene composite material involved in this invention at a frequency of 10 GHz. k The dielectric loss factor D is 1.9–2.2. f With a value ranging from 0.0001 to 0.00015, it has good application prospects in the field of high-frequency and high-speed communication.

[0028] To enable those skilled in the art to further understand the technical solution of the present invention, the technical solution of the present invention will be further described in detail below by way of embodiments.

[0029] Example 1

[0030] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.1% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0031] Example 2

[0032] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, and the mass of fluorinated graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0033] Example 3

[0034] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 1% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0035] Example 4

[0036] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 3% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0037] Example 5

[0038] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 50 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0039] Example 6

[0040] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 150 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0041] Example 7

[0042] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 25°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0043] Example 8

[0044] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 150°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0045] Example 9

[0046] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected, and polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder. The mass of fluorinated graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 10 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0047] Example 10

[0048] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected, and polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder. The mass of fluorinated graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 60 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0049] Example 11

[0050] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder. The mass of fluorinated graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed through a flat mold at a pressure of 100 MPa and a temperature of 80°C for 30 minutes to obtain PTFE / fluorinated graphene composite material.

[0051] Example 12

[0052] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder. The mass of fluorinated graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed through a closed mold at a pressure of 100 MPa and a temperature of 80°C for 30 minutes to obtain PTFE / fluorinated graphene composite material.

[0053] Comparative Example 1

[0054] First, polytetrafluoroethylene powder is pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold; then, it is pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain polytetrafluoroethylene material.

[0055] Comparative Example 2

[0056] Polytetrafluoroethylene (PTFE) powder and graphene powder were mixed evenly to obtain PTFE / graphene composite powder, and the mass of graphene was controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / graphene composite material.

[0057] Comparative Example 3

[0058] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 6% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0059] Comparative Example 4

[0060] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 8% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0061] Comparative Example 5

[0062] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 10% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0063] Comparative Example 6

[0064] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.85 and an oxygen-to-carbon molar ratio of 0.017 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0065] Comparative Example 7

[0066] Fluorinated graphene powder with a fluorine-to-carbon molar ratio of 0.90 and an oxygen-to-carbon molar ratio of 0.11 was selected. Polytetrafluoroethylene (PTFE) powder and fluorinated graphene powder were mixed evenly to obtain PTFE / fluorinated graphene composite powder, with the mass of fluorinated graphene controlled to be 0.5% of the mass of PTFE. The resulting composite powder was then pressed for 5 minutes at 10 MPa pressure and 25°C using a flat mold. Subsequently, it was pressed for 30 minutes at 100 MPa pressure and 80°C in a closed mold to obtain the PTFE / fluorinated graphene composite material.

[0067] The parameters of the polytetrafluoroethylene / fluorinated graphene composite materials obtained in Examples 1-12 and Comparative Examples 2-7, as well as the pure polytetrafluoroethylene material of Comparative Example 1, are shown in Table 1.

[0068] Table 1. Data Table of Polytetrafluoroethylene / Fluorographene (PTFE / FG) Composite Materials

[0069]

[0070]

[0071] Note: Molding pressure is the pressure exerted on the sample during sample preparation; compressive strength is the maximum compressive strength that the sample can withstand during mechanical property testing.

[0072] As can be seen from the test results of Examples 1-12 and Comparative Examples 1-5 in Table 1, when the mass ratio of fluorinated graphene to polytetrafluoroethylene (PTFE) is in the range of 0.1%-3%, the addition of fluorinated graphene can improve the compressive strength of PTFE while significantly reducing its dielectric loss and maintaining an extremely low dielectric constant. For example, in Example 2, the addition of only 0.5% fluorinated graphene (mass ratio of fluorinated graphene to PTFE) reduced its dielectric loss factor from 0.00021 to 0.00012, while also improving its compressive strength.

[0073] As can be seen from the test results of Examples 1-12 and Comparative Examples 6-7 in Table 1, when the fluorine-to-carbon ratio of fluorinated graphene is greater than or equal to 0.9 and its oxygen-to-carbon ratio is less than 0.05, the addition of fluorinated graphene can improve the compressive strength of polytetrafluoroethylene (PTFE) while significantly reducing the dielectric loss of PTFE and maintaining an extremely low dielectric constant. Therefore, in this application, the preferred fluorine-to-carbon molar ratio is 0.9 to 1.1, and the preferred oxygen-to-carbon molar ratio is 0.01 to 0.05.

[0074] To further investigate the polytetrafluoroethylene / fluorinated graphene composite material of the present invention, mechanical property tests were conducted below. Figure 1 The images shown in Example 2 of this invention compare the polytetrafluoroethylene / fluorinated graphene composite material sample with a mass ratio of 0.5 wt% (fluorinated graphene to polytetrafluoroethylene) before and after bending. The sample recovered its original shape after being bent and released, demonstrating its excellent flexibility. Furthermore, the compressive strength test results of the samples from Examples 1, 2, 3, 4, and Comparative Example 1 in Table 1 show that the addition of a small amount of fluorinated graphene not only reduces the dielectric loss of polytetrafluoroethylene but also effectively improves the compressive strength of the composite material.

[0075] In summary, the addition of a small amount (0.01% to 5.00 wt%) of fluorinated graphene not only effectively reduces the dielectric loss of polytetrafluoroethylene (PTFE), but also effectively improves the mechanical properties of PTFE. At the same time, the prepared PTFE / fluorinated graphene composite material also has excellent flexibility. The optimal mass ratio of fluorinated graphene to PTFE is 0.01% to 3.00 wt%.

[0076] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A polyvinyl fluoride / graphene fluoride composite material, characterized by, The polyfluoroethylene / fluorinated graphene composite material is composed of polytetrafluoroethylene and fluorinated graphene, and has a dielectric constant Dk of 1.9-2.2 and a dielectric loss factor Df of 0.0001-0.00015 at 10 GHz; the fluorocarbon molar ratio of the fluorinated graphene is 0.9-1.1, the oxygen-carbon molar ratio of the fluorinated graphene is 0.01-0.05, and the mass of the fluorinated graphene is 0.5-1.0 wt% of the mass of the polytetrafluoroethylene; The polyfluoroethylene / fluorinated graphene composite material is formed by the following steps: 1) uniformly mixing fluorinated graphene powder and polytetrafluoroethylene powder to obtain polytetrafluoroethylene / fluorinated graphene composite powder; 2) pressing the polytetrafluoroethylene / fluorinated graphene composite powder obtained in step 1) through a flat die without limitation on the four sides to obtain a preformed composite material; 3) further pressing the preformed composite material obtained in step 2) in a closed mold to obtain a polyfluoroethylene / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss at high operating frequency (GHz); In step 1), the particle size of the fluorinated graphene powder and the polytetrafluoroethylene powder ranges from 1 to 100 microns; In step 2), the process conditions for pressing are: pressure of 10 MP, pressing temperature of 25 ℃, and pressing time of 5 minutes; In step 3), the process conditions for pressing are: pressure of 100 MP, pressing temperature of 25-100 ℃, and pressing time of 10-50 minutes.

2. The polyvinyl fluoride / graphene fluoride composite material according to claim 1, characterized by The polyfluoroethylene / fluorinated graphene composite material is formed by mixing polytetrafluoroethylene and fluorinated graphene and then pressing by a molding method, and has a sheet layer shape.

3. A method of forming the polyvinyl fluoride / graphene fluoride composite material according to claim 1 or 2, characterized by, The method comprises the following steps: 1) uniformly mixing fluorinated graphene powder and polytetrafluoroethylene powder to obtain polytetrafluoroethylene / fluorinated graphene composite powder; 2) pressing the polytetrafluoroethylene / fluorinated graphene composite powder obtained in step 1) through a flat die without limitation on the four sides to obtain a preformed composite material; 3) further pressing the preformed composite material obtained in step 2) in a closed mold to obtain a polyfluoroethylene / fluorinated graphene composite material with ultra-low dielectric constant and ultra-low dielectric loss at high operating frequency (GHz); In step 1), the particle size of the fluorinated graphene powder and the polytetrafluoroethylene powder ranges from 1 to 100 microns; In step 2), the process conditions for pressing are: pressure of 10 MP, pressing temperature of 25 ℃, and pressing time of 5 minutes; In step 3), the process conditions for pressing are: pressure of 50-100 MP, pressing temperature of 25-100 ℃, and pressing time of 10-50 minutes.

4. The polyvinyl fluoride / graphene fluoride composite material molding method according to claim 3, characterized by In step 1), the particle size of the fluorinated graphene powder and the polytetrafluoroethylene powder ranges from 20 to 50 microns.

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