CN112359595B - Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof - Google Patents
Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof Download PDFInfo
- Publication number
- CN112359595B CN112359595B CN202011097354.4A CN202011097354A CN112359595B CN 112359595 B CN112359595 B CN 112359595B CN 202011097354 A CN202011097354 A CN 202011097354A CN 112359595 B CN112359595 B CN 112359595B
- Authority
- CN
- China
- Prior art keywords
- electromagnetic shielding
- flexible paper
- fiber
- shielding material
- paper
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
- D06M11/83—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with metals; with metal-generating compounds, e.g. metal carbonyls; Reduction of metal compounds on textiles
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
- D21H13/10—Organic non-cellulose fibres
- D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H13/26—Polyamides; Polyimides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/33—Synthetic macromolecular compounds
- D21H17/46—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/54—Synthetic macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen
- D21H17/56—Polyamines; Polyimines; Polyester-imides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/71—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes
- D21H17/74—Mixtures of material ; Pulp or paper comprising several different materials not incorporated by special processes of organic and inorganic material
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/009—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive fibres, e.g. metal fibres, carbon fibres, metallised textile fibres, electro-conductive mesh, woven, non-woven mat, fleece, cross-linked
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
- D06M2101/16—Synthetic fibres, other than mineral fibres
- D06M2101/30—Synthetic polymers consisting of macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Textile Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Paper (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
The invention discloses a multi-component flexible paper-based electromagnetic shielding material and a preparation method thereof, and belongs to the technical field of electromagnetic shielding. Based on electromagnetic pollution of a frequency band above 24GHz, the invention constructs a flexible paper-based conductive framework by using nano silver wires @ PI fibers and aramid pulp prepared by an in-situ synthesis method, impregnates oxidized multi-walled carbon nanotubes in pores of the flexible paper-based framework, and obtains the multi-component flexible paper-based electromagnetic shielding material after squeezing and drying. The invention not only solves the problem that the traditional paper base material is not resistant to high temperature and acid and alkali, but also overcomes the phenomena of uneven dispersion, agglomeration and the like of the nano silver wires and the oxidized multi-walled carbon nanotubes in the traditional filling method. In addition, the prepared multi-component flexible paper-based electromagnetic shielding material has the characteristics of ultrathin property, flexibility, high temperature resistance and easiness in processing, and meanwhile has excellent electromagnetic shielding performance and mechanical performance in a 5G high-frequency band, and is convenient to carry.
Description
Technical Field
The invention relates to a multi-component flexible paper-based electromagnetic shielding material and a preparation method thereof, belonging to the technical field of electromagnetic shielding.
Background
Currently, major countries around the world are accelerating the advance of 5G business pace, and the international telecommunication standards organization 3GPP protocol specifies that 5G independent networking mainly uses two sections of frequencies: FR1 frequency band and FR2 frequency band. The frequency range of the FR1 frequency band is 450MHz-6GHz, also called sub 6GHz frequency band; the frequency range of the FR2 frequency band is 24.25GHz-52.6GHz, which is commonly called millimeter Wave (mm Wave). Among them, the wavelength of the electromagnetic wave in the FR2 frequency band is short, the diffraction capability is poor, and the spatial attenuation of the signal is very serious. In order to realize the commercial application of 5G communication and meet higher mobile data requirements, more 5G communication base stations need to be deployed in the future to solve the problem of signal attenuation, and meanwhile, the requirements of users are met by adopting a high-frequency and medium-low frequency combined networking mode. The large-scale construction of the 5G communication base station can not avoid the generation of electromagnetic interference on the periphery, which can not only interfere the operation of various precise electronic equipment and influence the normal work of the equipment, but also can cause potential unpredictable harm to the human health. At present, the research on the electromagnetic shielding material with the frequency band of more than 24GHz is less, and the research on the high-efficiency electromagnetic shielding material applicable to the FR2 frequency band is of great significance in order to meet the requirement of the electromagnetic shielding material in the 5G era.
At present, relatively few researches are carried out on paper-based electromagnetic shielding materials, and electromagnetic interference in a frequency band below 12.4GHz is mostly acted on. For example: the invention patent of publication No. CN108794790A discloses a preparation method of carbon nanotube electromagnetic shielding paper, which takes microfibrillated cellulose and carbon nanotubes as raw materials and prepares the carbon nanotube electromagnetic shielding paper by vacuum filtration; the invention patent of publication No. CN107418512A discloses a preparation method of an ultrathin paper-based wave-absorbing material, which blends regenerated fibers and modified carbon nanotubes and adopts the traditional wet-process paper-making process to prepare the ultrathin paper-based wave-absorbing material; the invention patent of publication No. CN107938432A discloses a preparation method of a carbon nano paper composite material, which takes epoxy resin and nickel-cobalt-iron modified carbon nano tubes as raw materials and prepares the carbon nano paper composite material by casting. The above patents have a certain shielding effect on electromagnetic interference of electromagnetic waves with frequency band below 12.4GHz, but have certain limitations on electromagnetic interference of electromagnetic waves with frequency band above 24GHz and electromagnetic shielding application in high-temperature harsh environment, and limit the application of paper-based electromagnetic shielding materials in high-frequency band, high-temperature, acid-base environment or some special fields.
In addition, in order to realize a highly conductive interconnection network, the preparation of the conventional paper-based electromagnetic shielding material usually requires the filling of a high concentration of conductive filler. However, most of the conductive fillers are poor in dispersibility and are not uniformly dispersed in the paper base body, and the paper base electric conductor has breakpoints, so that the paper base electromagnetic shielding material is poor in conductivity. In order to realize high conductivity of the paper substrate, more conductive fillers are required to be loaded to form a continuous conductive channel, and the addition of excessive fillers can cause poor flexibility and poor processing performance of the paper-based electromagnetic shielding material, so that the application of the paper-based electromagnetic shielding material in precise flexible equipment is limited.
Therefore, it is required to provide a multi-component flexible paper-based electromagnetic shielding material capable of working in a frequency band above 24GHz and under a high-temperature harsh environment and a preparation method thereof.
Disclosure of Invention
Aiming at electromagnetic pollution of a frequency band above 24GHz, the invention provides a three-dimensional paper matrix constructed by high-temperature-resistant, acid-base-corrosion-resistant and high-performance Polyimide (PI) fibers and aramid pulp, wherein a nano silver wire is grown in situ on the surface of the PI fibers by adopting an in-situ synthesis method, and then the PI resin containing oxidized multi-walled carbon nanotubes is loaded by an impregnation method to enhance the mechanical property and the electromagnetic shielding property of the paper matrix material; on one hand, the in-situ synthesis of the silver nanowires and the impregnation of the oxidized multi-walled carbon nanotubes overcome the phenomena of uneven dispersion, agglomeration and the like of the silver nanowires and the oxidized multi-walled carbon nanotubes in the traditional filling method; on the other hand, the problems that the traditional paper-based electromagnetic shielding material is not high temperature resistant, acid-base resistant, poor in flexibility and the like are solved by adopting the high-performance PI fiber, the electromagnetic shielding performance and the mechanical performance of the paper-based electromagnetic shielding material are effectively improved, and the application range of the high-performance PI fiber composite material is widened.
The first purpose of the invention is to provide a method for preparing nano silver wire @ PI fiber, which comprises the following steps:
adding the acid-protonated PI fiber into the silver ion growth solution for uniform dispersion, and then carrying out in-situ growth at the temperature of 100-150 ℃ for 2-6h to obtain the nano silver line @ PI fiber.
In one embodiment of the invention, the in situ growth reaction is carried out at 130 ℃ for 4 h.
In one embodiment of the present invention, the method for preparing the acid-protonated PI fiber comprises: soaking PI fiber in 0.5-1.5mol/L sodium hydroxide solution for 0.3-1.5h, and washing with water; drying at 45-75 ℃ to obtain alkali-treated PI fiber; and then soaking the PI fiber after the alkali treatment in 0.1-0.8mol/L acetic acid solution for 0.3-1.5h, washing with water, and drying at 45-75 ℃ to obtain the acid-protonated PI fiber.
In one embodiment of the present invention, the method for preparing the acid-protonated PI fiber comprises: soaking the PI fiber in 1.0mol/L sodium hydroxide solution for 0.5h, and repeatedly washing with water for 5-10 times; drying at 45 ℃ to obtain alkali-treated PI fibers; and then soaking the PI fiber after the alkali treatment in 0.5mol/L acetic acid solution for 0.3-1.5h, repeatedly washing with water for 5-10 times, and drying at 45 ℃ to obtain the acid-protonated PI fiber.
In one embodiment of the present invention, the preparation method of the silver ion growth solution comprises: and adding polyvinylpyrrolidone into ethylene glycol for dissolving, and then adding a ferric trichloride solution and silver nitrate for uniformly mixing to obtain a silver ion growth solution.
In one embodiment of the present invention, in the preparation method of the silver ion growth solution, the mass volume ratio of the polyvinylpyrrolidone solution, the silver nitrate solution, the ethylene glycol solution and the ferric chloride solution is (0.1-0.5) g: (0.1-0.7) g: (10-30) mL: 35g of a soybean milk powder; further preferably (0.1 to 0.5) g: (0.25-0.6) g: (10-30) mL: 35g of a soybean milk powder; still more preferably 0.4 g: 0.25 g: 20mL of: 35g of the total weight.
In one embodiment of the invention, the concentration of ferric trichloride in the preparation method of the silver ion growth solution is 0.5-1.5 mol/L; further preferably 0.5 mol/L.
In an embodiment of the present invention, the preparation method of the silver ion growth solution specifically comprises: 0.4g of polyvinylpyrrolidone is added into 20mL of ethylene glycol to be dissolved, and then 35g of 0.5mol/L ferric trichloride solution and 0.25g of silver nitrate are added and mixed to obtain the silver ion growth solution.
In one embodiment of the invention, the uniform dispersion is ultrasonic dispersion, specifically, the ultrasonic power is 300W, and the ultrasonic time is 0.3 h.
In one embodiment of the invention, the mass-to-volume ratio of the acid-protonated PI fibers to the silver ion growth solution is (1-3) g: 30 mL.
The second purpose of the invention is to prepare the nano silver wire @ PI fiber prepared by the method.
The third object of the present invention is to provide a method for preparing a multi-component flexible paper-based electromagnetic shielding material, comprising the steps of:
(1) preparing a flexible paper-based conductive framework: uniformly mixing the nano silver wire @ PI fiber and the aramid fiber pulp, and obtaining a flexible paper-based conductive framework by adopting a wet papermaking method;
(2) preparing a multi-component flexible paper-based electromagnetic shielding material: preparing a mixed solution of N, N-dimethylacetamide, oxidized multi-walled carbon nanotubes and polyimide resin, then dipping the flexible paper-based conductive framework in the mixed solution, and drying to obtain the multi-component flexible paper-based electromagnetic shielding material.
In one embodiment of the invention, the mass ratio of the nano silver wire @ PI fiber to the aramid pulp in the step (1) is (8-10): (1-3); more preferably 8: 2.
in one embodiment of the present invention, the mass ratio of the N, N-dimethylacetamide, the oxidized multiwalled carbon nanotubes and the polyimide resin in the mixed solution in the step (2) is (3-6): (2-5): (14-18); more preferably 5:4: 16.
in one embodiment of the present invention, the wet papermaking method in step (2) specifically includes: weighing the nano silver wire @ PI fiber and the aramid fiber pulp according to the proportion, uniformly dispersing, then making paper by a paper sheet former, squeezing and drying (at 90-120 ℃) to obtain the flexible paper-based conductive framework.
In one embodiment of the present invention, the preparation method of the mixed solution in the step (2) comprises: firstly weighing N, N-dimethylacetamide and oxidized multi-walled carbon nanotubes, uniformly dispersing in a beaker, then adding polyimide resin, and uniformly dispersing to obtain a resin mixed solution containing the oxidized multi-walled carbon nanotubes, wherein the mass ratio of the N, N-dimethylacetamide to the oxidized multi-walled carbon nanotubes is (3-6): (2-5): (14-18).
In one embodiment of the present invention, the method for preparing oxidized multi-walled carbon nanotubes in step (2) comprises: weighing 0.1-1g of multi-walled carbon nano tube in 300mL of mixed acid solution (the volume ratio of concentrated sulfuric acid solution to concentrated nitric acid solution is (2-5): 0.5-1.5), the mass fraction of concentrated sulfuric acid solution is 95-98%, and the mass fraction of concentrated nitric acid solution is 65-68%), carrying out ultrasonic oscillation, transferring the mixed acid solution into a container for reaction, and centrifuging, washing and drying after the reaction is finished to obtain the oxidized multi-walled carbon nano tube.
In an embodiment of the invention, the ultrasonic parameters in the preparation method of the oxidized multi-walled carbon nanotube in the step (2) are ultrasonic power of 200-400W and ultrasonic time of 0.1-1.0 h.
In one embodiment of the present invention, in the method for preparing oxidized multi-walled carbon nanotubes in step (2), the washing and drying are performed 5 to 10 times and the drying is performed at 45 to 75 ℃.
In one embodiment of the invention, the reaction conditions in the preparation method of the oxidized multi-walled carbon nanotube in the step (2) are treatment at 50-80 ℃ for 2-5 h; further preferably at 70 ℃ for 4 hours.
In one embodiment of the present invention, the number of times of the impregnation in the step (2) is 2 to 5 times.
In one embodiment of the present invention, the drying in step (2) is drying at 90-120 ℃.
The fourth purpose of the invention is that the multicomponent flexible paper-based electromagnetic shielding material prepared by the method is prepared.
The fifth purpose of the invention is to apply the multi-component flexible paper-based electromagnetic shielding material in the fields of electromagnetic shielding, flame retardance and electric conduction.
The invention has the beneficial effects that:
(1) the electromagnetic pollution of the frequency band above 24GHz is aimed at by the electromagnetic shielding material, and the electromagnetic pollution of the frequency band below 12.4GHz is aimed at by the electromagnetic shielding material different from the conventional paper-based electromagnetic shielding material.
(2) The invention provides an effective and simple-to-operate method for preparing the nano silver wire @ PI fiber by using the in-situ synthesis method with stable working environment, so that the nano silver wire is uniformly distributed on the surface of the PI fiber, and the nano silver wire @ PI fiber with good conductivity and stability is obtained. Meanwhile, the problems of poor paper forming performance, low paper performance and the like of the PI fiber are solved.
(3) The in-situ synthesis method and the dipping method used in the invention solve the problems of uneven distribution, easy agglomeration and the like of the nano silver wires and the oxidized multi-walled carbon nanotubes in the paper-based electromagnetic shielding material prepared by the traditional filling method.
(4) The multi-component flexible paper-based electromagnetic shielding material has the characteristics of flexibility, ultrathin property, light weight, high temperature resistance and flame retardance; the problems of heavy thickness and difficult processing of the traditional metal electromagnetic shielding material are solved, and the problem that the traditional paper-based electromagnetic shielding material cannot work in high-temperature and harsh environments is also solved.
(5) The tensile strength of the multi-component flexible paper-based electromagnetic shielding material reaches over 22.36MPa and can reach up to 31.27 MPa; the elongation at break reaches more than 2.97 percent and can reach as high as 3.82 percent; the surface conductivity reaches more than 5.45S/cm, and can reach 11.03S/cm; electromagnetic interference Shielding Effectiveness (SE)T) Microwave reflection coefficient (SE)R) And microwave absorption coefficient (SE)A) The electromagnetic shielding performance can reach more than 45.83dB, more than 10.42dB and more than 33.7dB, can reach 85.4dB, 15.8dB and 69.6dB, and has stable electromagnetic shielding effect when working at the temperature of 450 ℃.
Drawings
FIG. 1 is a physical diagram of a multi-component flexible paper-based electromagnetic shielding material of example 1 and PI fiber base paper of comparative example 1; wherein, (a) is a PI fiber base paper real image, and (b) is a multi-component flexible paper-based electromagnetic shielding material real image.
Fig. 2 is a bending test of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1.
Fig. 3 is a thermal performance test of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1.
Fig. 4 is a tensile test result of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1 and example 3.
Fig. 5 is a test result of surface conductivity of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1 and example 3.
Fig. 6 shows the electromagnetic shielding performance test results of the multi-component flexible paper-based electromagnetic shielding materials obtained in example 1 and example 3.
Detailed Description
The following description of the preferred embodiments of the present invention is provided for the purpose of better illustrating the invention and is not intended to limit the invention thereto.
And (3) testing mechanical properties: testing the tensile property of the flexible paper-based electromagnetic shielding material by using a PT-1198GTD-C tensile pressure testing machine, and then analyzing the test result; cutting the prepared multi-component flexible paper-based electromagnetic shielding material into a specified size (the width is 15 +/-0.1 mm, the length is longer than the required experiment length and is convenient for clamping a sample) according to the national standard (GB/T453-.
Measurement of surface conductivity: the surface conductivity (the surface conductivity is the reciprocal of the surface resistivity) of the multi-component flexible paper-based electromagnetic shielding material is tested by adopting a ST-2258C type four-probe resistance meter of Suzhou lattice Limited company to characterize the conductivity of the material. The measuring range of the surface resistivity measured by the instrument is 10 multiplied by 103-20×1032Omega cm. The surface conductivity is a constant independent of the basic size of the material, is determined by the properties of the material, and reflects the difference of the conductivity performance among the materials. The smaller the value, the higher the conductivity of the material under the same dimensional conditions.
Where σ is the conductivity and ρ is the resistivity.
Thermal performance testing: a Q500 thermogravimetric analyzer of American TA instruments company is adopted to test the thermal property change of the multi-component flexible paper-based electromagnetic shielding material. The test process is analyzed in a nitrogen environment, the measuring range is 40-800 ℃, and the heating rate is 10 ℃/min.
And (3) testing the electromagnetic shielding property: electromagnetic shielding effectiveness was measured in the 18.0-26.5 GHz frequency range using a vector network analyzer (VNA, Agilent, N5234A, USA) waveguide method according to ASTM D5568-08 standard; cutting the sample into a rectangle of 10.95mm × 4.5 mm; according to the recorded scattering parameter (S)11And S21) The EMI Shielding Effectiveness (SE) is calculated according to the following equations (2) to (4)T) Microwave reflection coefficient (SE)R) And microwave absorption coefficient (SE)A)；
SER(dB)＝-10lg(1-S11)2 (2)
SET(dB)＝SER(dB)+SEA(dB)+SEM(dB) (4)
Wherein SEMFor multiple internal reflection of electromagnetic waves, when SETAbove 10dB can be ignored;
in order to ensure the accuracy of the test, the sample is firstly subjected to humidity balancing for 24 hours in a constant-temperature and constant-humidity laboratory so as to reduce the influence of the environmental temperature and humidity on the experimental result; each test was performed 5 times and the average was taken.
Example 1
A method for preparing a multi-component flexible paper-based electromagnetic shielding material comprises the following steps:
(1) preparation of acid protonated PI fibers:
soaking the PI fiber in 1.0mol/L sodium hydroxide solution for 0.5h, and repeatedly washing with water for 5 times; drying at 45 ℃ to obtain alkali-treated PI fibers; then soaking the PI fiber after the alkali treatment in 0.5mol/L acetic acid solution for 0.5h, repeatedly washing with water for 5 times, and drying at 45 ℃ to obtain acid-protonated PI fiber;
(2) preparation of nano silver wire @ PI fiber:
adding 0.4g of polyvinylpyrrolidone into 20mL of ethylene glycol for dissolving, then adding 35g of 0.5mol/L ferric trichloride solution and 0.25g of silver nitrate for mixing to obtain silver ion growth solution; then adding 2.0g of PI fiber into 100mL of silver ion growth solution, and performing ultrasonic dispersion uniformly, wherein the ultrasonic power is 300W, and the ultrasonic time is 0.3 h; then, carrying out original position length 4h at 130 ℃ to obtain a nano silver line @ PI fiber;
(3) preparing a flexible paper-based conductive framework:
the quantitative quantity of the preset flexible paper-based conductive framework is 60g/cm2Weighing the nano silver wire @ PI fiber and the aramid fiber pulp according to the proportion (the mass proportion of the nano silver wire @ PI fiber to the aramid fiber pulp is 8:2), uniformly dispersing the nano silver wire @ PI fiber and the aramid fiber pulp, and passing through a paper sheetMaking paper by a former, squeezing and drying to obtain a flexible paper-based conductive framework;
(4) preparing oxidized multi-wall carbon nanotubes:
weighing 0.2g of multi-walled carbon nanotube in 300mL of mixed acid solution (the volume ratio of concentrated sulfuric acid solution to concentrated nitric acid solution is 3:1, the mass fraction of concentrated sulfuric acid solution is 96%, the mass fraction of concentrated nitric acid solution is 66%, carrying out ultrasonic oscillation with the ultrasonic power of 300W and the ultrasonic time of 0.3h, then transferring the multi-walled carbon nanotube into a three-neck flask, treating for 4h at 70 ℃, centrifuging, washing and drying to obtain the oxidized multi-walled carbon nanotube;
(5) weighing N, N-dimethylacetamide, oxidized multi-walled carbon nanotubes and polyimide resin (the mass ratio is 5:4:16), uniformly dispersing the N, N-dimethylacetamide and the oxidized multi-walled carbon nanotubes in a beaker, then adding the polyimide resin to uniformly disperse to obtain a mixed solution, soaking the prepared flexible paper-based conductive framework in the resin mixed solution containing the oxidized multi-walled carbon nanotubes for 3 times, and drying at the temperature of 105 ℃ to obtain the multi-component flexible paper-based electromagnetic shielding material (a physical picture is shown in figure 1 (b)).
Through tests, the obtained multi-component flexible paper-based electromagnetic shielding material has the thickness of 0.19mm, the tensile strength of 31.27MPa, the elongation at break of 3.82 percent, the surface conductivity of 11.03S/cm and the electromagnetic interference Shielding Efficiency (SE)T) Microwave reflection coefficient (SE)R) And microwave absorption coefficient (SE)A) 85.4dB, 15.8dB and 69.6dB respectively, and the electromagnetic shielding effect is stable when the electromagnetic shielding device works below 450 ℃.
Fig. 2 is a bending test and a thermogravimetric curve of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1. As can be seen from fig. 2: the multi-component flexible paper-based electromagnetic shielding material prepared in the embodiment 1 can be repeatedly bent within the range of 0-180 degrees, and has good flexibility.
Fig. 3 is a thermogravimetric test of the multi-component flexible paper-based electromagnetic shielding material obtained in example 1. As can be seen from fig. 3, the pyrolysis temperature of the multi-component flexible paper-based electromagnetic shielding material prepared in example 1 is about 450 ℃.
The multi-component flexible paper-based electromagnetic shielding material prepared in the embodiment 1 is processed at 25, 200, 400 and 600 ℃ for 60min to obtain the multi-component flexible paper-based electromagnetic shielding material after high-temperature processing, and the performance test results are shown in table 1.
TABLE 1 test results of multi-component flexible paper-based electromagnetic shielding material after high-temperature treatment
Note: "/" indicates that the flexible paper-based electromagnetic shielding material has been decomposed and has no electromagnetic shielding property.
Example 2
The addition amounts of silver nitrate in the embodiment 1 are adjusted to be 0.1g, 0.4g and 0.6g, and other parameters are kept consistent with those in the embodiment 1, so that the multi-component flexible paper-based electromagnetic shielding material with high-efficiency electromagnetic shielding performance is obtained.
The obtained multi-component flexible paper-based electromagnetic shielding material is subjected to performance test, and the test result is shown in table 2. As can be seen from Table 2, when the addition amount of silver nitrate is 0.25g (example 1), the prepared multi-component flexible paper-based electromagnetic shielding material has good comprehensive performance through analysis of mechanical properties, electrical conductivity and electromagnetic shielding performance.
Table 2 Performance test results of multi-component flexible paper-based electromagnetic shielding material obtained by adding different amounts of silver nitrate
Example 3
And (3) adjusting the in-situ growth time of the nano silver wire in the step (2) in the embodiment 1 to be 2h and 6h, and keeping other parameters unchanged to obtain the multi-component flexible paper-based electromagnetic shielding material with high-efficiency electromagnetic shielding performance.
The obtained multi-component flexible paper-based electromagnetic shielding material is subjected to performance test, and the test results are shown in table 3, and fig. 4, 5 and 6. From the test results, it can be seen that when the in-situ growth time of the nano silver wire is 4h (example 1), the prepared multi-component flexible paper-based electromagnetic shielding material has good comprehensive performance from the analysis of mechanical properties, electrical conductivity and electromagnetic shielding properties.
TABLE 3 Performance test results of multi-component flexible paper-based electromagnetic shielding material obtained by different in-situ growth time
Example 4
Adjusting the in-situ growth temperature of the nano silver wire in the step (2) in the embodiment 1 as shown in table 4, and keeping other parameters unchanged to obtain the multi-component flexible paper-based electromagnetic shielding material with high-efficiency electromagnetic shielding performance.
The obtained multi-component flexible paper-based electromagnetic shielding material is subjected to performance test, and the test result is shown in table 4. As can be seen from table 4, when the growth temperature of the nano silver wire is 130 ℃ (example 1), the multi-component flexible paper-based electromagnetic shielding material prepared has good comprehensive performance according to the analysis of mechanical properties, electrical conductivity and electromagnetic shielding performance.
TABLE 4 Performance test results of multi-component flexible paper-based electromagnetic shielding material obtained at different in-situ growth temperatures
Note: "/" indicates no detection, and no electromagnetic shielding effect.
Example 5
The dipping times of the flexible paper-based conductive framework in the resin mixed solution containing oxidized multi-walled carbon nanotubes in the step (5) in the embodiment 1 are adjusted to be shown in table 5, and other parameters are kept unchanged, so that the multi-component flexible paper-based electromagnetic shielding material with high-efficiency electromagnetic shielding performance is obtained.
The obtained multi-component flexible paper-based electromagnetic shielding material is subjected to performance test, and the test result is shown in table 5. As can be seen from table 5, when the dipping times is 3 times (example 1), the multi-component flexible paper-based electromagnetic shielding material prepared by the method has good comprehensive performance through analysis of mechanical properties, conductivity and electromagnetic shielding properties.
TABLE 5 Performance test results of multi-component flexible paper-based electromagnetic shielding material obtained by different dipping times
Comparative example 1
The preparation method of the PI fiber base paper comprises the following steps:
(1) preparation of acid protonated PI fibers:
soaking the PI fiber in 1.0mol/L sodium hydroxide solution for 0.5h, and repeatedly washing with water for 5 times; drying at 45 ℃ to obtain alkali-treated PI fibers; then soaking the PI fiber after the alkali treatment in 0.5mol/L acetic acid solution for 0.5h, repeatedly washing with water for 5 times, and drying at 45 ℃ to obtain acid-protonated PI fiber;
(2) preparing PI fiber base paper:
the quantitative rate of the preset PI fiber base paper is 60g/cm2The PI fiber and aramid pulp are weighed according to the proportion (the proportion of the PI fiber to the aramid pulp is 8:2), are uniformly dispersed, are made into paper by a paper former, and are pressed and dried to obtain PI fiber base paper (a picture of a real object is shown in figure 1 (a)).
Comparative example 2
A method of making a flexible paper-based electromagnetic shielding material, comprising the steps of:
(1) preparation of acid protonated PI fibers:
soaking the PI fiber in 1.0mol/L sodium hydroxide solution for 0.5h, and repeatedly washing with water for 5 times; drying at 45 ℃ to obtain alkali-treated PI fibers; then soaking the PI fiber after the alkali treatment in 0.5mol/L acetic acid solution for 0.5h, repeatedly washing with water for 5 times, and drying at 45 ℃ to obtain acid-protonated PI fiber;
(2) preparation of nano silver wire @ PI fiber:
adding 0.4g of polyvinylpyrrolidone into 20mL of ethylene glycol for dissolving, then adding 35g of 0.5mol/L ferric trichloride solution and 0.25g of silver nitrate for mixing to obtain silver ion growth solution; then adding 2.0g of PI fiber into 100mL of silver ion growth solution, and performing ultrasonic dispersion uniformly, wherein the ultrasonic power is 300W, and the ultrasonic time is 0.3 h; then carrying out in-situ growth reaction for 4h at 130 ℃ to obtain a nano silver line @ PI fiber;
(3) preparing a flexible paper-based conductive framework:
the quantitative quantity of the preset flexible paper-based conductive framework is 60g/cm2Weighing the nano silver wire @ PI fiber and the aramid pulp according to a ratio (the mass ratio of the nano silver wire @ PI fiber to the aramid pulp is 8:2), uniformly dispersing, making paper by a paper former, squeezing and drying to obtain a flexible paper-based conductive framework;
(4) weighing N, N-dimethylacetamide and polyimide resin (the mass ratio is 5:16) and adding the N, N-dimethylacetamide and the polyimide resin into a beaker to be uniformly dispersed to obtain a resin mixed solution, dipping the prepared flexible paper-based conductive framework in the resin mixed solution for 3 times, and drying at 105 ℃ to obtain the paper-based electromagnetic shielding material.
Comparative example 3
Weighing N, N-dimethylacetamide, oxidized multi-walled carbon nanotubes and polyimide resin (the mass ratio is 5:4:16), uniformly dispersing the N, N-dimethylacetamide and the oxidized multi-walled carbon nanotubes in a beaker, then adding the polyimide resin to uniformly disperse to obtain a mixed solution, soaking PI base paper (prepared by the method of comparative example 1) in the resin mixed solution containing the oxidized multi-walled carbon nanotubes for 3 times, and drying at 105 ℃ to obtain the paper-based electromagnetic shielding material.
Comparative example 4
The step (2) in the adjustment example 1 is: adding 0.4g of polyvinylpyrrolidone into 20mL of ethylene glycol for dissolving, then adding 35g of 0.5mol/L ferric trichloride solution and 0.25g of silver nitrate for mixing to obtain silver ion growth solution; and (3) soaking 2.0g of PI fiber in the silver ion growth solution, and keeping other parameters and the embodiment 1 unchanged to obtain the multi-component flexible paper-based electromagnetic shielding material.
Comparative example 5
In the step (1) of the adjustment example 1, only the PI fiber is subjected to alkali treatment, and the acid protonation is omitted; other parameters and example 1 are kept unchanged, and the multi-component flexible paper-based electromagnetic shielding material is obtained.
The multi-component flexible paper-based electromagnetic shielding materials obtained in comparative examples 1-5 were subjected to performance tests, and the test results are shown in table 6.
Table 6 test results of multi-component flexible paper-based electromagnetic shielding materials obtained in comparative examples 1 to 5
Note: "/" indicates no detection, and no electromagnetic shielding effect.
The multi-component flexible paper-based electromagnetic shielding materials obtained in comparative examples 2, 3 and 4 were treated at 25, 200, 400 and 600 ℃ for 60min to obtain the multi-component flexible paper-based electromagnetic shielding materials after high temperature treatment, and the performance test results are shown in table 7.
TABLE 7 conductivity test results of multi-component flexible paper-based electromagnetic shielding material after high-temperature treatment
Note: "/" indicates that the flexible paper-based electromagnetic shielding material has been decomposed and has no electromagnetic shielding property.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. A method for preparing a multi-component flexible paper-based electromagnetic shielding material is characterized by comprising the following steps:
(1) preparing a flexible paper-based conductive framework: uniformly mixing the nano silver wire @ PI fiber and the aramid fiber pulp, and obtaining a flexible paper-based conductive framework by adopting a wet papermaking method;
(2) preparing a flexible paper-based electromagnetic shielding material: preparing a mixed solution of N, N-dimethylacetamide, oxidized multi-walled carbon nanotubes and polyimide resin, then dipping the flexible paper-based conductive framework in the mixed solution, and drying to obtain a multi-component flexible paper-based electromagnetic shielding material;
the method for preparing the nano silver wire @ PI fiber in the step (1) comprises the following steps:
adding the acid-protonated PI fiber into the silver ion growth solution to be uniformly dispersed, and then carrying out in-situ growth for 4h at 130 ℃ to obtain a nano silver line @ PI fiber; the preparation method of the silver ion growth solution comprises the following steps: adding polyvinylpyrrolidone into ethylene glycol for dissolving, then adding ferric trichloride solution and silver nitrate, and uniformly mixing to obtain silver ion growth solution; wherein the mass volume ratio of the polyvinylpyrrolidone, the silver nitrate, the glycol and the ferric trichloride solution is 0.4 g: 0.25 g: 20mL of: 35g of a soybean milk powder; the preparation method of the acid-protonated PI fiber comprises the following steps: soaking the PI fiber in 1.0mol/L sodium hydroxide solution for 0.5h, and repeatedly washing with water for 5-10 times; drying at 45 ℃ to obtain alkali-treated PI fibers; then soaking the PI fiber after the alkali treatment in 0.5mol/L acetic acid solution for 0.3-1.5h, repeatedly washing with water for 5-10 times, and drying at 45 ℃ to obtain acid-protonated PI fiber;
the mass ratio of the nano silver wire @ PI fiber to the aramid pulp in the step (1) is (8-10): (1-3);
the mass ratio of the N, N-dimethylacetamide, the oxidized multi-walled carbon nanotubes and the polyimide resin in the mixed solution in the step (2) is (3-6): (2-5): (14-18).
2. The method of claim 1, wherein the number of impregnations of step (2) is 2-5.
3. The method according to claim 1 or 2, wherein the oxidized multi-walled carbon nanotube of step (2) is prepared by: weighing a multi-walled carbon nanotube, placing the multi-walled carbon nanotube in a mixed acid solution, carrying out ultrasonic oscillation, transferring the multi-walled carbon nanotube into a container for reaction, centrifuging, washing and drying after the reaction is finished to obtain an oxidized multi-walled carbon nanotube; wherein the mixed acid solution is a mixed solution of a concentrated sulfuric acid solution with the mass fraction of 95-98% and a concentrated nitric acid solution with the mass fraction of 65-68%, and the volume ratio of the two is (2-5): (0.5-1.5).
4. The multi-component flexible paper-based electromagnetic shielding material prepared by the method of any one of claims 1 to 3.
5. The multi-component flexible paper-based electromagnetic shielding material of claim 4 is applied to the fields of electromagnetic shielding, flame retardance and electric conduction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011097354.4A CN112359595B (en) | 2020-10-14 | 2020-10-14 | Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011097354.4A CN112359595B (en) | 2020-10-14 | 2020-10-14 | Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112359595A CN112359595A (en) | 2021-02-12 |
| CN112359595B true CN112359595B (en) | 2021-11-16 |
Family
ID=74506747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011097354.4A Active CN112359595B (en) | 2020-10-14 | 2020-10-14 | Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112359595B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114164708B (en) * | 2021-11-11 | 2022-08-02 | 江南大学 | Electromagnetic shielding paper based on conductive MOF material modification and preparation method thereof |
| CN114075800B (en) * | 2021-11-30 | 2022-10-11 | 江南大学 | Paper-based electromagnetic shielding composite material with flame retardant property and preparation method and application thereof |
| CN115379751A (en) * | 2022-07-26 | 2022-11-22 | 无锡纤发新材料科技有限公司 | Method for preparing electromagnetic shielding material by recycling carbon fibers from activated carbon mask |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101660264A (en) * | 2009-09-11 | 2010-03-03 | 北京化工大学 | Method for preparing polyimide/silver composite conductive fiber |
| CN102259190A (en) * | 2011-06-16 | 2011-11-30 | 浙江科创新材料科技有限公司 | Method for quickly preparing nano silver wires with high length-diameter ratio in large batch |
| CN102785437B (en) * | 2012-07-19 | 2016-08-03 | 中国航空工业集团公司北京航空材料研究院 | A kind of composite conducting thin layer and its preparation method and application |
| CN102899959B (en) * | 2012-09-27 | 2014-10-29 | 陕西科技大学 | Para-position aramid fiber paper used for cellular material and preparation method thereof |
| CN102953288B (en) * | 2012-11-02 | 2015-08-19 | 陕西科技大学 | A kind of PPTA-pulp strengthens the preparation method of polyimide fiber paper |
| CN104882224A (en) * | 2015-04-28 | 2015-09-02 | 中科院广州化学有限公司南雄材料生产基地 | Preparation of transparent conducting film based on nano-silver wires and caboxylated carbon nano-materials |
| CN106120458B (en) * | 2016-06-28 | 2017-10-20 | 江南大学 | A kind of preparation method of polyimides conductive paper |
| CN110777559B (en) * | 2019-10-09 | 2021-11-02 | 东华大学 | Polyimide composite paper with catalytic performance and SERS performance and preparation thereof |
| CN110982102B (en) * | 2019-12-23 | 2022-06-28 | 宁波长阳科技股份有限公司 | Polyimide film, preparation method thereof, artificial graphite sheet and electronic product |
-
2020
- 2020-10-14 CN CN202011097354.4A patent/CN112359595B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112359595A (en) | 2021-02-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112359595B (en) | Multi-component flexible paper-based electromagnetic shielding material and preparation method thereof | |
| Shui et al. | Nickel filament polymer-matrix composites with low surface impedance and high electromagnetic interference shielding effectiveness | |
| Liang et al. | Electromagnetic shielding property of carbon fiber felt made of different types of short-chopped carbon fibers | |
| Sun et al. | Broadband absorption of macro pyramid structure based flame retardant absorbers | |
| CN102504495A (en) | Epoxy resin composite wave-absorbing material and preparation method thereof | |
| CN105119046A (en) | Compact-type 2.45GHz flexible wearable graphene antenna | |
| CN106479433A (en) | A kind of Graphene composite wave-suction material and preparation method thereof | |
| CN113462357B (en) | Wave-absorbing particles and preparation method and application of composite material thereof | |
| CN106671502A (en) | Short carbon fiber based electromagnetic shielding composite material and preparation method thereof | |
| CN107722932A (en) | A kind of carbon/polyaniline inhales the preparation method of ripple microballoon | |
| CN114835932B (en) | Copper nanowire/aramid nanofiber composite conductive film and preparation method thereof | |
| CN111453715A (en) | Ultra-light efficient electromagnetic shielding composite material and preparation method thereof | |
| CN110862716A (en) | Graphene composite conductive ink and preparation method thereof | |
| CN109098038A (en) | A kind of electromagnetic shielding paper and preparation method thereof | |
| Hu et al. | Facile synthesis of FeNi nanoparticle-loaded carbon nanocomposite fibers for enhanced microwave absorption performance | |
| KR20040078002A (en) | Carbon Nano-Composite Materials for Shielding of Electromagnetic Wave and Preparation Method Thereof | |
| CN114075800B (en) | Paper-based electromagnetic shielding composite material with flame retardant property and preparation method and application thereof | |
| Gültekin et al. | Evaluation of the electromagnetic shielding effectiveness of carbon-based screen printed polyester fabrics | |
| Zhang et al. | Study on material of polymer-based electromagnetic shielding composites | |
| Shi et al. | Strain-responsive 3D hierarchical composites for smart microwave absorption modulation within broad C-Ku band | |
| US12049728B2 (en) | Electromagnetic shielding paper based on modification of conductive MOF material and preparation method thereof | |
| CN103451991B (en) | Preparation method of lignin enhanced graphite conductive paper | |
| CN102964571B (en) | Preparation method of barium ferrite/carbon nanotube/poly(3-methylthiophene) composite wave-absorbing material | |
| Jiang et al. | Preparation and optimization of conductive PDMS composite foams with absorption-dominated electromagnetic interference shielding performance via silvered aramid microfibers | |
| CN110485208B (en) | Composite material with electromagnetic shielding function and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |