Preparation method of fluorine-containing PBO nanofiber paper with heat conduction and wave transmission

Abstract

The application relates to the technical field of heat-permeable polymer materials, and discloses a preparation method of fluorine-containing PBO nanofiber paper with heat conduction and wave permeability, which comprises the following steps: obtaining fluorine-containing PBO precursors through a co-condensation reaction; diluting the fluorine-containing PBO precursors with an organic solvent to obtain a precursor solution, and then putting the precursor solution into high-speed stirring deionized water, collecting solid phases through suction filtration to obtain precursor nanofibers; dispersing the precursor nanofibers in an alcohol dispersant to obtain a dispersion liquid, collecting solid phases through suction filtration, and then performing heat treatment after cold-press drying to obtain fluorine-containing PBO nanofiber paper with heat conduction and wave permeability. The preparation process is simple, the prepared fluorine-containing PBO nanofiber paper with heat conduction and wave permeability has excellent heat conduction performance, low dielectric constant and excellent tensile strength.

Description

Technical Field

[0001] This application relates to the field of heat-transparent polymer materials technology, and in particular to a method for preparing a heat-conducting and wave-transparent fluorinated PBO nanofiber paper. Background Technology

[0002] The rapid development of electronic communication technology has led to the miniaturization, integration, and high-frequency operation of electronic components in devices. Under high-power electromagnetic density, these devices are prone to heat accumulation, which reduces their wave transmission performance, shortens their lifespan, and can even pose safety hazards. There is an urgent need for materials that combine high wave transmission and high thermal conductivity to ensure stable electromagnetic wave transmission while efficiently and promptly transferring heat to the external environment, thus guaranteeing stable device operation.

[0003] Currently, commonly used microwave-transparent materials include polymer matrices such as epoxy resin, cyanate ester resin, and aramid paper. As a novel microwave-transparent material, poly(p-phenylenebenzodioxazole) nanofiber paper exhibits superior thermal conductivity, microwave transmission performance, and mechanical properties compared to commonly used polymer-based microwave-transparent materials. However, its complex manufacturing process leads to higher costs; and its in-plane thermal conductivity (λ...) ∥ It is still difficult to meet the heat dissipation / conduction requirements of high-power electronic communication equipment (λ). ∥ >2.5 W / (m·K)).

[0004] Therefore, how to improve the intrinsic thermal conductivity of poly(p-phenylenebenzodioxazole) nanofiber paper through a simplified preparation process, and further reduce its dielectric constant (real part of dielectric constant: ~2.5) to ensure stable electromagnetic wave transmission while maintaining its thermal conductivity and mechanical properties, has become a key problem that urgently needs to be solved in the field of PNF paper. Summary of the Invention

[0005] This application provides a method for preparing thermally conductive and microwave-transparent fluorinated PBO nanofiber paper, aiming to solve the technical problems of low thermal conductivity and microwave transmission performance of existing PBO nanofiber paper, as well as complex preparation processes.

[0006] To achieve the above objectives, the present application adopts the following technical solution.

[0007] A first aspect of this application provides a method for preparing thermally conductive and wave-transparent fluorinated PBO nanofiber paper, comprising: S1, through a co-condensation reaction, yields a fluorinated PBO precursor, the chemical structure of which is shown below: ; Where m is an integer between 250 and 600, and n is an integer between 20 and 120; S2, the fluorinated PBO precursor is diluted with an organic solvent to obtain a precursor solution; The precursor solution was added to deionized water under high-speed stirring, and the solid phase was collected by filtration to obtain precursor nanofibers. S3, the precursor nanofibers are dispersed in an alcohol dispersant to obtain a dispersion; the dispersion is filtered to collect the solid phase, and after cold pressing and drying, it is subjected to heat treatment to obtain thermally conductive and wave-transparent fluorinated PBO nanofiber paper.

[0008] Preferably, step S1 specifically includes: dissolving the solubilizer in an organic solvent under an inert atmosphere to obtain a composite solvent; 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and an acid-binding agent were dissolved in a composite solvent, and then terephthaloyl chloride was added to carry out a co-condensation reaction to obtain a fluorinated PBO precursor.

[0009] More preferably, the solubilizer includes any one of lithium chloride, calcium chloride, or lithium bromide; The acid-binding agent includes any one of propylene oxide, triethylamine, or pyridine. The organic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

[0010] More preferably, the ratio of the total molar amount of 3,3'-dihydroxybenzidine and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the molar amount of terephthaloyl chloride is 1:0.95~1.05; The molar ratio of 3,3'-dihydroxybenzidine to 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is 1:0.05~0.25; The content of solubilizer in the composite solvent is 0.02~0.04 g / mL; The molar ratio of the acid-binding agent to terephthaloyl chloride is 1~3:1; The ratio of the organic solvent to terephthaloyl chloride is 3~10 mL / 1 mmol; The temperature of the copolymerization reaction is -10~10℃. o C, the reaction time is 1~20h.

[0011] Preferably, in step S2, the precursor solution is added to deionized water at a rate of 10-200 mL / min; The high-speed stirring rate is 100~20000 rpm.

[0012] Preferably, the alcohol dispersant includes any one of methanol, ethanol, isopropanol, propylene glycol, glycerol, or ethylene glycol.

[0013] Preferably, the mass fraction of the fluorinated PBO precursor in the precursor solution in S2 is 0.01~1wt%; The mass ratio of deionized water to precursor solution in S2 is 1:0.5~100; The solid content of the dispersion in S3 is 0.01~1wt%.

[0014] Preferably, the cold pressing drying temperature in S3 is 0~30℃ and the time is 48~96 hours.

[0015] Preferably, the atmosphere for the heat treatment in S3 is a nitrogen or argon atmosphere; The heat treatment includes: first heating up for a first-stage heat treatment, then heating up for a second-stage heat treatment, then heating up for a third-stage heat treatment, and then cooling down to room temperature. The temperature of the first-stage heat treatment is 90~110℃, and the time is 50~70min; The second-stage heat treatment is performed at a temperature of 190~210℃ for 50~70 minutes. The three-stage heat treatment is performed at a temperature of 300~400℃ for a time of 50~70min.

[0016] More preferably, the heating rate is 5~10℃ / min; the cooling rate is 5~10℃ / min.

[0017] Compared with the prior art, the beneficial effects of this application are as follows: The fluorinated PBO nanofiber paper provided in this application improves the crystallinity of nanofibers by introducing trifluoromethyl groups, thereby reducing phonon scattering during heat transfer and enhancing the thermal conductivity of the nanofiber paper. The fluorinated groups also reduce the dielectric constant of the nanofibers, decreasing electromagnetic wave reflection and absorption during electromagnetic transmission and improving their wave transmission performance. Furthermore, the fluorinated groups reduce intermolecular interactions between fluorinated PBO precursors in organic solvents, decreasing the diameter of the fluorinated PBO nanofibers and their precursor nanofibers, increasing their specific surface area, and enhancing inter-nanofiber interactions to improve their tensile properties.

[0018] The preparation process of this application is simple, and the prepared thermally conductive and wave-transparent fluorinated PBO nanofiber paper has excellent thermal conductivity. λ ∥ It has a dielectric constant of 3.31 W / (m·K), a low dielectric constant (real part of dielectric constant is 2.29) and excellent tensile strength (335.4 MPa). Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Fluorine-containing PBO precursor nanofibers pre FPBO-5 pre FPBO-10 and pre Fourier transform infrared spectrum of FPBO-15; Figure 2 for pre Transmission electron microscope images, energy dispersive spectroscopy (EDS) images of fluorine element distribution, and diameter distribution statistics of FPBO-5; Figure 3 for pre Transmission electron microscope images, energy dispersive spectroscopy (EDS) images of fluorine element distribution, and diameter distribution statistics of FPBO-10; Figure 4 for pre Transmission electron microscope images, energy dispersive spectroscopy (EDS) images of fluorine distribution, and diameter distribution statistics of FPBO-15; Figure 5 Fourier transform infrared spectra of the fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 of Examples 1-3. Figure 6 X-ray diffraction curves of fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 in Examples 1-3; Figure 7 Scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) images of the fluorine-containing PBO nanofiber papers FPNF-5, FPNF-10, and FPNF-15 from Examples 1-3 are shown. Figure 8 The graph shows the dielectric constant test results of the fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 in Examples 1-3; Figure 9 The graph shows the transmittance test results of the fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 in Examples 1-3; Figure 10 The graph shows the thermal conductivity test results of the fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 in Examples 1-3; Figure 11The figures show the tensile strength test results of the fluorinated PBO nanofiber papers FPNF-5, FPNF-10 and FPNF-15 in Examples 1-3. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0023] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0024] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0025] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0026] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0027] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood as each intermediate value between the upper and lower limits of the specifically disclosed range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] A first aspect of this application provides a method for preparing thermally conductive and wave-transparent fluorinated PBO nanofiber paper, comprising: S1, through a co-condensation reaction, yields a fluorinated PBO precursor; its preparation methods include: Under an inert atmosphere, the solubilizer is dissolved in an organic solvent to obtain a composite solvent; The solubilizer is selected from any one of lithium chloride, calcium chloride, or lithium bromide, preferably lithium chloride; the organic solvent is N-methylpyrrolidone or N,N-dimethylformamide; and the inert atmosphere is at least one of argon or nitrogen, preferably nitrogen.

[0030] 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and an acid-binding agent were dissolved in a composite solvent, and then terephthaloyl chloride was added to carry out a co-condensation reaction to obtain a fluorinated PBO precursor.

[0031] The acid-binding agent is selected from any one of propylene oxide, triethylamine, or pyridine, preferably propylene oxide.

[0032] The preferred temperature for the copolymerization reaction is -10 to 10 °C. o C, more preferably -5~5 o C; The reaction time is preferably 1~20h, more preferably 10~15h.

[0033] The chemical structure of the precursor is shown below: ; Where m is an integer between 250 and 600, and n is an integer between 20 and 120.

[0034] In this application, the ratio of the total molar number of 3,3'-dihydroxybenzidine and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the molar number of terephthaloyl chloride is preferably 1:0.95~1.05, more preferably 1:1; The molar ratio of 3,3'-dihydroxybenzidine to 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is 1:0.05~0.25.

[0035] The content of solubilizer in the composite solvent is 0.02~0.04 g / mL.

[0036] The molar ratio of the acid-binding agent to terephthaloyl chloride is preferably 1 to 3:1, more preferably 1:1.

[0037] The preferred ratio of the organic solvent to terephthaloyl chloride is 3-10 mL / 1 mmol, more preferably 5 mL / 1 mmol.

[0038] S2, the fluorinated PBO precursor is diluted with an organic solvent to obtain a precursor solution; The precursor solution was added to deionized water under high-speed stirring, and the solid phase was collected by filtration to obtain precursor nanofibers. The feeding rate of the precursor solution is preferably 10-200 mL / min, more preferably 50-80 mL / min; The high-speed stirring rate is 100~20000 rpm, more preferably 16000~18000 rpm.

[0039] In this application, the mass fraction of the fluorinated PBO precursor in the precursor solution is preferably 0.01~1wt%, more preferably 0.1~0.5wt%; The preferred mass ratio of deionized water to precursor solution is 1:0.5~100, and more preferably 1:5~10.

[0040] S3, the precursor nanofibers are dispersed in an alcohol-based dispersant to obtain a dispersion; the dispersion is filtered and the solid phase is collected, then cold-pressed, dried, and heat-treated to obtain a thermally conductive and wave-transparent fluorinated PBO nanofiber paper, the chemical structure of which is shown below: ; Where m is an integer between 250 and 600, and n is an integer between 20 and 120.

[0041] In this application, the alcohol dispersant is preferably any one of methanol, ethanol, isopropanol, propylene glycol, glycerol, or ethylene glycol, and more preferably ethanol.

[0042] The dispersion has a solid content of 0.01 to 1 wt%, more preferably 0.1 to 0.5 wt%.

[0043] In this application, the cold-press drying specifically involves: pressing the precursor nanofibers collected after filtration into a flat plate, and then drying them at 0~30℃ for 48~96 hours. More preferably, the drying temperature is 15~25℃, and the drying time is 72~80 hours.

[0044] In this application, the atmosphere for the heat treatment is nitrogen or argon, preferably nitrogen. The heat treatment includes: first, heating up for a first-stage heat treatment; then heating up for a second-stage heat treatment; then heating up for a third-stage heat treatment; and finally cooling down to room temperature. The heating rate is 5~10℃ / min; the cooling rate is 5~10℃ / min.

[0045] The temperature of the first-stage heat treatment is 90~110℃, and the time is 50~70min; The second-stage heat treatment is performed at a temperature of 190~210℃ for 50~70 minutes. The three-stage heat treatment is performed at a temperature of 300~400℃ for a time of 50~70min.

[0046] After heat treatment, the precursor nanofibers undergo dehydration condensation to obtain fluorinated PBO nanofiber paper.

[0047] The present application will be further described below through specific embodiments.

[0048] Example 1: This example provides a method for preparing fluorinated PBO nanofiber paper, comprising: S1, under nitrogen atmosphere, 2.5 g of lithium chloride was dissolved in 100 mL of N-methylpyrrolidone and added to a 250 mL flask. After stirring evenly, 19 mmol of 3,3'-dihydroxybenzidine (4.10 g) and 1 mmol of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (0.37 g) were added to the system, followed by 3 mL of propylene oxide. After complete dissolution, 20 mmol of terephthaloyl chloride (4.06 g) was added, and the mixture was heated at -500°C. o After stirring the reaction at C for 13 hours, a solution containing the fluorine-containing PBO precursor was obtained, denoted as […]. pre FPBO-5 solution.

[0049] S2, will pre The FPBO-5 solution was diluted with N-methylpyrrolidone to a concentration of 1 wt%. pre FPBO-5 solution, then subjected to fluid shear at 18000 rpm preFPBO-5 solution was dispersed in deionized water to obtain fluorinated PBO precursor nanofibers, denoted as FPBO-5. pre FPNF-5 was repeatedly washed with plenty of deionized water to neutralize it.

[0050] S3, will pre FPNF-5 is dispersed in ethanol and prepared. pre A dispersion of FPNF-5 with a content of 0.2 wt% was filtered to form a film, and then cold-pressed and dried at 1 MPa for 48 h. The film was then hot-pressed at 100℃ for 1 h under a nitrogen atmosphere and a pressure of 1 MPa, followed by hot-pressing at 200℃ for 1 h, and finally hot-pressed at 300℃ for 1 h to obtain a thermally conductive and wave-transparent fluorinated PBO nanofiber paper, denoted as FPNF-5.

[0051] Example 2: This example provides a method for preparing fluorinated PBO nanofiber paper.

[0052] The difference between Example 2 and Example 1 is that in step S1, the amount of 3,3'-dihydroxybenzidine used is 18 mmol (3.88 g), and the amount of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane used is 2 mmol (0.74 g), while the rest is the same as in Example 1.

[0053] The fluorinated PBO precursor prepared in Example 2 is denoted as... pre FPBO-10; The thermally conductive and wave-transparent fluorinated PBO nanofiber paper prepared is designated as FPNF-10.

[0054] Example 3: This example provides a method for preparing fluorinated PBO nanofiber paper.

[0055] The difference between Example 3 and Example 1 is that in step S1, the amount of 3,3'-dihydroxybenzidine is 17 mmol (3.67 g), and the amount of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is 3 mmol (1.11 g), while the rest are the same as in Example 1.

[0056] The fluorinated PBO precursor prepared in Example 3 is denoted as... pre FPBO-15; The thermally conductive and wave-transparent fluorinated PBO nanofiber paper prepared is designated as FPNF-15.

[0057] The fluorinated PBO precursors prepared in Examples 1-3 were characterized by Fourier transform infrared spectroscopy to verify their structure, and the results are as follows: Figure 1 As shown.

[0058] from Figure 1 It can be seen that the three fluorinated PBO precursors pre FPBO-5 pre FPBO-10 and pre FPBO-15 at 3410 cm -1 1640 cm -1 and 1495 cm -1 The presence of characteristic peaks at all locations, belonging to amide groups, indicates that the acyl chloride and amino group have successfully reacted.

[0059] Fluorine-containing PBO precursor nanofibers prepared in Examples 1-3 pre FPBO-5 pre FPBO-10 and pre The fluorine distribution of FPBO-15 was characterized by transmission electron microscopy and energy dispersive spectroscopy, and the diameter of the nanofibers was statistically analyzed. The results are as follows: Figures 2-4 As shown.

[0060] in, Figure 2 , Figure 3 and Figure 4 They are respectively pre FPBO-5 pre FPBO-10 and pre The test results of FPBO-15 are shown in the figure. Figures 2-4 Figure a is a transmission electron microscope image, figure b is a fluorine element distribution map, and figure c is a nanofiber diameter distribution map.

[0061] from Figures 2 to 4 It can be seen that the fluorinated PBO precursors prepared in Examples 1-3 were all successfully used to prepare fluorinated PBO precursor nanofibers, and the fluorine element was uniformly distributed in the fluorinated PBO precursor nanofibers. Among them, the fluorinated PBO precursor nanofibers prepared in Example 2 had a smaller diameter and a narrower distribution.

[0062] The fluorinated PBO nanofiber papers FPBO-5, FPBO-10, and FPBO-15 prepared in Examples 1-3 were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. The results are as follows: Figure 5-7 As shown.

[0063] in, Figure 5 The Fourier transform infrared spectra of FPBO-5, FPBO-10, and FPBO-15 show that, after heat treatment, the four types of thermally conductive and wave-transparent fluorinated PBO nanofiber papers exhibit different wavelengths at 1610 cm⁻¹. -1 and 1053 cm -1 The presence of characteristic C=N and COC peaks corresponding to the oxazole ring, and the disappearance of characteristic absorption peaks of the amide bond, indicates that the nanofibers have undergone a cyclization reaction and transformed into fluorinated PBO nanofibers.

[0064] Figure 6The X-ray diffraction results for FPBO-5, FPBO-10, and FPBO-15 are shown. It can be seen that after heat treatment, the four types of fluorinated PBO nanofiber papers show similar results at 17.3°C. o and 29.8 o The (200) and (210) crystal plane diffraction peaks belonging to fluorinated poly(p-phenylenebenzodioxazole) appeared, and the crystallinity was good. Among them, the (200) crystal peak of FPNF-10 had the highest intensity and the best crystallinity.

[0065] Figure 7 The images show scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) images of fluorine distribution in FPBO-5, FPBO-10, and FPBO-15. It can be seen that after heat treatment, all four types of fluorine-containing PBO nanofiber papers exhibit a layered structure and a uniform distribution of fluorine.

[0066] The dielectric properties of the fluorinated PBO nanofiber papers FPBO-5, FPBO-10, and FPBO-15 prepared in Examples 1-3 were tested using a WK6500B precision impedance analyzer. The results are as follows: Figure 8 As shown. From Figure 8 It can be seen that at 1 MHz, the real part and imaginary part of the dielectric constant of FPNF-5, FPNF-10 and FPNF-15 are 2.35 and 0.032, 2.29 and 0.023, and 2.15 and 0.122, respectively. Their real part of dielectric constant is less than 2.5, indicating that they have low dielectric constant.

[0067] The transmittance of the fluorinated PBO nanofiber papers FPBO-5, FPBO-10, and FPBO-15 prepared in Examples 1-3 was tested using an MS4644A vector network analyzer. The results are as follows: Figure 9 As shown, at 10 GHz, the transmittance of FPNF-5, FPNF-10, and FPNF-15 are 95.0%, 95.4%, and 95.2%, respectively, all exhibiting excellent transmittance performance.

[0068] The thermal conductivity of the fluorinated PBO nanofiber papers FPBO-5, FPBO-10, and FPBO-15 prepared in Examples 1-3 was tested using a Hot Disk TPS2200 thermal conductivity tester. The results are as follows: Figure 10 As shown, their in-plane thermal conductivity is 3.20 W / (m·K), 3.31 W / (m·K), and 2.67 W / (m·K), respectively; their inter-plane thermal conductivity is 0.25 W / (m·K), 0.26 W / (m·K), and 0.21 W / (m·K), respectively; all exhibiting excellent thermal conductivity.

[0069] The tensile properties of the fluorinated PBO nanofiber papers FPBO-5, FPBO-10, and FPBO-15 prepared in Examples 1-3 were tested using an ST-D200 instrument from Sitech Instruments Co., Ltd. The results are as follows: Figure 11 As shown, their tensile strengths are 315.6 MPa, 335.4 MPa and 227.6 MPa, respectively, all of which exhibit excellent mechanical stability.

[0070] Although this application has been described in detail in this specification with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A method for preparing a thermally conductive and wave-transparent fluorinated PBO nanofiber paper, characterized in that, include: S1, through a co-condensation reaction, yields a fluorinated PBO precursor, the chemical structure of which is shown below: ； Where m is an integer between 250 and 600, and n is an integer between 20 and 120; S2, the fluorinated PBO precursor is diluted with an organic solvent to obtain a precursor solution; The precursor solution was added to deionized water under high-speed stirring, and the solid phase was collected by filtration to obtain precursor nanofibers. S3, the precursor nanofibers are dispersed in an alcohol dispersant to obtain a dispersion; the dispersion is filtered to collect the solid phase, and after cold pressing and drying, it is subjected to heat treatment to obtain thermally conductive and wave-transparent fluorinated PBO nanofiber paper.

2. The preparation method according to claim 1, characterized in that, Step S1 specifically includes: dissolving the solubilizer in an organic solvent under an inert atmosphere to obtain a composite solvent; 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and an acid-binding agent were dissolved in a composite solvent, and then terephthaloyl chloride was added to carry out a co-condensation reaction to obtain a fluorinated PBO precursor.

3. The preparation method according to claim 2, characterized in that, The solubilizer includes any one of lithium chloride, calcium chloride, or lithium bromide; The acid-binding agent includes any one of propylene oxide, triethylamine, or pyridine. The organic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

4. The preparation method according to claim 2, characterized in that, The ratio of the total molar amount of 3,3'-dihydroxybenzidine and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to the molar amount of terephthaloyl chloride is 1:0.95~1.05; The molar ratio of 3,3'-dihydroxybenzidine to 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is 1:0.05~0.25; The content of solubilizer in the composite solvent is 0.02~0.04 g / mL; The molar ratio of the acid-binding agent to terephthaloyl chloride is 1~3:1; The ratio of the organic solvent to terephthaloyl chloride is 3~10 mL / 1 mmol; The temperature of the copolymerization reaction is -10~10℃. o C, the reaction time is 1~20h.

5. The preparation method according to claim 1, characterized in that, In step S2, the precursor solution is added to deionized water at a rate of 10-200 mL / min; The high-speed stirring rate is 100~20000 rpm.

6. The preparation method according to claim 1, characterized in that, The alcohol dispersant includes any one of methanol, ethanol, isopropanol, propylene glycol, glycerol, or ethylene glycol.

7. The preparation method according to claim 1, characterized in that, The mass fraction of fluorinated PBO precursor in the precursor solution described in S2 is 0.01~1wt%; The mass ratio of deionized water to precursor solution in S2 is 1:0.5~100; The solid content of the dispersion in S3 is 0.01~1wt%.

8. The preparation method according to claim 1, characterized in that, The cold pressing drying temperature described in S3 is 0~30℃, and the time is 48~96h.

9. The preparation method according to claim 1, characterized in that, The heat treatment atmosphere described in S3 is a nitrogen or argon atmosphere; The heat treatment includes: first heating up for a first-stage heat treatment, then heating up for a second-stage heat treatment, then heating up for a third-stage heat treatment, and then cooling down to room temperature. The temperature of the first-stage heat treatment is 90~110℃, and the time is 50~70min; The second-stage heat treatment is performed at a temperature of 190~210℃ for 50~70 minutes. The three-stage heat treatment is performed at a temperature of 300~400℃ for a time of 50~70min.

10. The preparation method according to claim 9, characterized in that, The heating rate is 5~10℃ / min; the cooling rate is 5~10℃ / min.

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