CN113136083A - Composite electromagnetic shielding material for low-frequency wave band and preparation method thereof - Google Patents
Composite electromagnetic shielding material for low-frequency wave band and preparation method thereof Download PDFInfo
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- CN113136083A CN113136083A CN202110428685.XA CN202110428685A CN113136083A CN 113136083 A CN113136083 A CN 113136083A CN 202110428685 A CN202110428685 A CN 202110428685A CN 113136083 A CN113136083 A CN 113136083A
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- 239000000463 material Substances 0.000 title claims abstract description 34
- 239000002131 composite material Substances 0.000 title claims abstract description 22
- 238000002360 preparation method Methods 0.000 title abstract description 6
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims abstract description 18
- 239000004926 polymethyl methacrylate Substances 0.000 claims abstract description 18
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000002041 carbon nanotube Substances 0.000 claims abstract description 16
- 229910021393 carbon nanotube Inorganic materials 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 13
- 238000001816 cooling Methods 0.000 claims abstract description 7
- 238000010008 shearing Methods 0.000 claims description 12
- 238000001125 extrusion Methods 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 229910052799 carbon Inorganic materials 0.000 claims description 2
- 150000001247 metal acetylides Chemical class 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims description 2
- 238000005303 weighing Methods 0.000 claims description 2
- 238000000034 method Methods 0.000 claims 6
- 230000000694 effects Effects 0.000 abstract description 6
- 238000005469 granulation Methods 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 2
- 230000003179 granulation Effects 0.000 abstract 1
- 238000002347 injection Methods 0.000 description 12
- 239000007924 injection Substances 0.000 description 12
- 230000005540 biological transmission Effects 0.000 description 10
- 238000001514 detection method Methods 0.000 description 10
- 238000012360 testing method Methods 0.000 description 8
- 238000011161 development Methods 0.000 description 6
- 230000005670 electromagnetic radiation Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 4
- 239000008188 pellet Substances 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 2
- 229920001940 conductive polymer Polymers 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 206010000210 abortion Diseases 0.000 description 1
- 231100000176 abortion Toxicity 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 210000000748 cardiovascular system Anatomy 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 230000002124 endocrine Effects 0.000 description 1
- 230000001605 fetal effect Effects 0.000 description 1
- 210000000987 immune system Anatomy 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 210000000653 nervous system Anatomy 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/04—Carbon
- C08K3/041—Carbon nanotubes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/10—Metal compounds
- C08K3/14—Carbides
-
- 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
Abstract
The invention discloses a composite electromagnetic shielding material for low-frequency wave bands and a preparation method thereof, wherein the composite electromagnetic shielding material is prepared from the following components in parts by weight: 93% -95% of polymethyl methacrylate, 1% -5% of carbon nano tube and 1% -5% of two-dimensional carbide, and the components of the electromagnetic shielding material are improved by carrying out melt blending, cooling and granulation through a double-screw extruder, so that the novel composite electromagnetic shielding material has a good electromagnetic shielding effect in a low-frequency band, and has the advantages of high frequency efficiency, wide frequency band, light weight and thin thickness compared with the conventional metal shielding material.
Description
Technical Field
The invention belongs to the field of electromagnetic shielding materials, and particularly relates to a composite electromagnetic shielding material for a low-frequency band and a preparation method thereof.
Background
With the rapid development of modern information technology, electromagnetic waves are applied in large scale in the fields of electronic products, data transmission, electronic communication, wireless network systems, satellite emission, modern detection technology, radar detection technology, medical diagnosis and the like, thereby providing great convenience for the life of people and bringing about serious electromagnetic radiation pollution. Electromagnetic radiation pollution is invisible and invisible, but serious in harm. Firstly, the electromagnetic wave can cause endocrine disturbance of human body, the function of nervous system, immune system and cardiovascular system is reduced, and also can cause fetal distortion and even abortion of pregnant women, thus seriously harming the health of people. Secondly, electromagnetic waves emitted by different radiation signal sources can interfere with each other, so that the accuracy of data transmission is reduced, and the stability and reliability of electronic elements and electrical equipment are affected. For example, medical equipment or electronic experimental equipment may malfunction and lose data due to electromagnetic interference, and communication equipment may be interfered by electromagnetic waves to cause signal interruption and noise increase. Moreover, electromagnetic wave leakage can cause important information leakage in the aspects of national politics, economy, military and the like, and electromagnetic wave interference can influence the use of national accurate guidance weaponry and strategic materials, so that irreparable loss of national safety and economic development is caused.
In consideration of the diversity and unavailability of electromagnetic wave pollution sources, the adoption of electromagnetic shielding measures is an important feasible way for controlling pollution and reducing electromagnetic radiation hazards. The electromagnetic shielding material has great application value in the civil, commercial and military fields, and the electromagnetic shielding material with high efficiency researched and launched has very important practical significance and strategic significance.
With the development of science and technology, new requirements are put forward on the development of electromagnetic shielding materials, and the research direction of the electromagnetic shielding materials is towards the development of broadband, low density and high absorption. The conductive polymer composite material has the advantages of flexible and adjustable conductivity, low density, high specific strength, easy molding, low cost and the like, and has bright application prospect in the field of electromagnetic shielding.
Most of the results have been made on the electromagnetic shielding performance of the conductive composite material in the high-frequency band range of 2-18 GHz, but the research on the electromagnetic shielding in the low-frequency band (< 100 MHz) is less. The low-frequency electromagnetic radiation has obvious influence on weak current equipment and communication equipment, especially the intensity change of the low-frequency electromagnetic interference is irregular and can fluctuate greatly in a short time, and the source of the low-frequency electromagnetic radiation is wide and diversified.
In conclusion, the development of the conductive polymer composite electromagnetic shielding material in the low-frequency band has important significance for low-frequency electromagnetic shielding.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a composite electromagnetic shielding material for a low-frequency band and a preparation method thereof.
The technical scheme adopted by the invention is that the composite electromagnetic shielding material for the low-frequency band comprises the following components in parts by weight: 93-95% of polymethyl methacrylate, 1-5% of carbon nano tube and 1-5% of two-dimensional carbide.
Preferably, the content of the polymethyl methacrylate is as follows: 94 percent.
The invention also provides a preparation method of the composite electromagnetic shielding material for the low-frequency wave band, which comprises the following steps:
(1) weighing polymethyl methacrylate, carbon nano tubes and two-dimensional carbides according to a certain proportion, drying and fully and uniformly mixing on a high-speed mixer;
(2) and (2) melting, blending, cooling and granulating the material particles blended and manufactured in the step (1) by a double-screw extruder.
Preferably, the length-diameter ratio of the twin-screw extruder in the step (2) is 40: 1.
preferably, the temperature of a nozzle of the twin-screw extruder in the step (2) is controlled to be 200-210 ℃, and the rotating speed of the twin-screw extruder is 45-55 RPM.
Preferably, the twin screw is rotated at 50 RPM.
Preferably, the twin-screw structure of the twin-screw extruder from the feed inlet to the extrusion die orifice is divided into six zones, and the conveying section, the strong shearing section, the conveying section, the shearing section and the conveying section are sequentially arranged from one zone to six zones.
Preferably, the working temperature of each section of the twin-screw extruder is as follows: a first region: 180-190 ℃, and in the second zone: 190-200 ℃, and a third zone: 195-200 ℃, fourth zone: 205-210 ℃, and a fifth zone: 200-210 ℃, sixth zone: 200 to 210 ℃.
The technical scheme of the invention improves the components of the electromagnetic shielding material, and the novel composite electromagnetic shielding material has good electromagnetic shielding effect in low-frequency band (< 100 MHz), and has the advantages of high frequency efficiency, wide frequency band, light weight and thin thickness compared with the conventional metal shielding material. The composite electromagnetic shielding material plays a good safety precaution role in the field of electromagnetic interference shielding of electronics, aerospace, airplanes, wearable equipment, automobiles and the like.
Detailed Description
The present invention is described in further detail below, it being noted that the following examples are intended to facilitate the understanding of the present invention, but are not intended to limit the invention in any way.
The following specific embodiments are provided to disclose the performance of various combination examples. Therefore, this patent specification should be considered to disclose all possible combinations of the described technical solutions.
Example 1
Firstly, according to the weight ratio of 94% of polymethyl methacrylate (PMMA), 5% of Carbon Nano Tube (CNT) and 1% of two-dimensional carbide (MXene), methyl methacrylate, carbon nano tube and two-dimensional carbide are weighed, dried and fully mixed uniformly on a high-speed mixer. Then, melt blending, cooling and re-granulation were performed using a twin-screw extruder. The length-diameter ratio of the double-screw extruder is 40: 1, a double-screw structure from a feed inlet of a double-screw extruder to an extrusion die orifice is divided into six zones, a transmission section, a strong shearing section, a transmission section, a shearing section and a conveying section are sequentially and respectively arranged from one zone to six zones, and the melting temperatures of the first zone to the six zones are sequentially and respectively controlled to be 180 ℃, 190 ℃, 200 ℃, 210 ℃, 200 ℃ and 200 ℃. The nozzle temperature was controlled at 200 ℃ and the twin screw speed was 45 RPM. The pellets after melt blending extrusion were dried in a drying oven at 85 ℃ for 6 hours, and then injection-molded at an injection temperature of 200 ℃, a mold-locking pressure of 100MPa, an injection pressure of 60MPa, a holding pressure of 50MPa, and a holding time of 10 seconds. Specimens of different shapes and sizes, required for subsequent testing, were cut from the injection molded plaques.
The product obtained above was tested as follows:
and testing the electromagnetic shielding effectiveness of the material by adopting a vector network analyzer. The test sample used for testing is a circular ring-shaped test sample with the inner diameter of 3 mm, the outer diameter of 7 mm and the thickness of 2 mm.
Example 2
Firstly, according to the weight ratio of 94% of polymethyl methacrylate (PMMA), 4% of Carbon Nano Tubes (CNT) and 2% of two-dimensional carbide (MXene), the methyl methacrylate, the carbon nano tubes and the two-dimensional carbide are weighed, dried and fully mixed uniformly on a high-speed mixer. Then, melt blending, cooling and re-granulation were performed using a twin-screw extruder. The length-diameter ratio of the double-screw extruder is 40: 1, a double-screw structure from a feed inlet of a double-screw extruder to an extrusion die orifice is divided into six zones, a transmission section, a strong shearing section, a transmission section, a shearing section and a conveying section are sequentially and respectively arranged from one zone to six zones, and the melting temperature from one zone to six zones is sequentially and respectively controlled to be 180 ℃, 195 ℃, 200 ℃, 210 ℃, 205 ℃ and 205 ℃. The nozzle temperature was controlled at 205 ℃ and the twin screw speed was 50 RPM. The pellets after melt blending extrusion were dried in a drying oven at 85 ℃ for 6 hours, and then injection-molded at an injection temperature of 200 ℃, a mold-locking pressure of 110MPa, an injection pressure of 50MPa, a holding pressure of 40MPa, and a holding time of 20 seconds. Specimens of different shapes and sizes, required for subsequent testing, were cut from the injection molded plaques.
Detecting the prepared product: the detection method and the detection content are completely the same as those of the embodiment 1.
Example 3
Firstly, 94% of polymethyl methacrylate (PMMA), 3% of Carbon Nano Tubes (CNT) and 3% of two-dimensional carbide (MXene) by weight are weighed, dried and fully mixed uniformly on a high-speed mixer. Then, melt blending, cooling and re-granulation were performed using a twin-screw extruder. The length-diameter ratio of the double-screw extruder is 40: 1, a double-screw structure from a feed inlet of a double-screw extruder to an extrusion die orifice is divided into six zones, a transmission section, a strong shearing section, a transmission section, a shearing section and a conveying section are sequentially and respectively arranged from one zone to six zones, and the melting temperature from one zone to six zones is sequentially and respectively controlled to be 190 ℃, 200 ℃, 195 ℃, 205 ℃, 210 ℃ and 210 ℃. The nozzle temperature was controlled at 200 ℃ and the twin screw speed was 50 RPM. The pellets after melt blending extrusion were dried in a drying oven at 80 ℃ for 8 hours, and then injection-molded at an injection temperature of 205 ℃, a mold-locking pressure of 105MPa, an injection pressure of 55MPa, a holding pressure of 50MPa, and a holding time of 10 seconds. Specimens of different shapes and sizes, required for subsequent testing, were cut from the injection molded plaques.
Detecting the prepared product: the detection method and the detection content are completely the same as those of the embodiment 1.
Example 4
Firstly, 94% of polymethyl methacrylate (PMMA), 1% of Carbon Nano Tube (CNT) and 5% of two-dimensional carbide (MXene) by weight are weighed, dried and fully mixed uniformly on a high-speed mixer. Then, melt blending, cooling and re-granulation were performed using a twin-screw extruder. The length-diameter ratio of the double-screw extruder is 40: 1, a double-screw structure from a feed inlet of a double-screw extruder to an extrusion die orifice is divided into six zones, a transmission section, a strong shearing section, a transmission section, a shearing section and a conveying section are sequentially and respectively arranged from one zone to six zones, the melting temperature of the zones from one zone to six zones is sequentially and respectively controlled to be 180 ℃, 190 ℃, 200 ℃, 210 ℃, 200 ℃ and 200 ℃, the nozzle temperature is controlled to be 210 ℃, and the rotating speed of the double screws is 55 RPM. The pellets after melt blending extrusion were dried in a drying oven at 85 ℃ for 6 hours, and then injection-molded at an injection temperature of 200 ℃, a mold-locking pressure of 100MPa, an injection pressure of 60MPa, a holding pressure of 45MPa, and a holding time of 15 seconds. Specimens of different shapes and sizes, required for subsequent testing, were cut from the injection molded plaques.
Detecting the prepared product: the detection method and the detection content are completely the same as those of the embodiment 1.
Comparative example 1
The polymethyl methacrylate (PMMA) product is detected, and the detection method and the detection content are completely the same as those in the example 1.
Table 1 electromagnetic shielding effectiveness of examples 1 to 4 and comparative example 1 are shown below.
According to the above results, it can be seen that the electromagnetic shielding effect of comparative example 1 is not good when only polymethyl methacrylate is used as the shielding material, wherein the mass ratio of the carbon nanotubes and the two-dimensional carbide has a great influence on the electromagnetic shielding effect, the electromagnetic shielding effect of example 1 is better at a frequency of 1MHz or 100MHz, and the electromagnetic shielding effect of example 2 is better at a frequency of 20Hz or 100 kHz.
Claims (8)
1. The composite electromagnetic shielding material for the low-frequency waveband is characterized by comprising the following components in parts by weight: 93-95% of polymethyl methacrylate, 1-5% of carbon nano tube and 1-5% of two-dimensional carbide.
2. The composite electromagnetic shielding material for low frequency band according to claim 1, wherein the content of the polymethyl methacrylate is: 94 percent.
3. A method for preparing the composite electromagnetic shielding material for the low frequency band according to claim 1, comprising the steps of:
(1) weighing polymethyl methacrylate, carbon nano tubes and two-dimensional carbides according to a certain proportion, drying and fully and uniformly mixing on a high-speed mixer;
(2) and (2) melting, blending, cooling and granulating the material particles blended and manufactured in the step (1) by a double-screw extruder.
4. The method for preparing a composite electromagnetic shielding material for low frequency band according to claim 3, wherein the length/diameter ratio of the twin-screw extruder in the step (2) is 40: 1.
5. the method for preparing a composite electromagnetic shielding material for low frequency band according to claim 3, wherein the temperature of the nozzle of the twin-screw extruder in the step (2) is controlled to be 200 to 210 ℃ and the rotation speed of the twin-screw extruder is 45 to 55 RPM.
6. The method for preparing a composite electromagnetic shielding material for low frequency band according to claim 5, wherein the rotation speed of the twin screw is 50 RPM.
7. The method for preparing the composite electromagnetic shielding material for the low frequency band according to claim 3, wherein the twin-screw structure of the twin-screw extruder from the feeding port to the extrusion die port is divided into six zones, and the conveying section, the strong shearing section, the conveying section, the shearing section and the conveying section are sequentially arranged from one zone to six zones.
8. The method for preparing a composite electromagnetic shielding material for low frequency band according to claim 7, wherein the operating temperature of each section of the twin-screw extruder is as follows: a first region: 180-190 ℃, and in the second zone: 190-200 ℃, and a third zone: 195-200 ℃, fourth zone: 205-210 ℃, and a fifth zone: 200-210 ℃, sixth zone: 200 to 210 ℃.
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| CN202110428685.XA CN113136083A (en) | 2021-04-21 | 2021-04-21 | Composite electromagnetic shielding material for low-frequency wave band and preparation method thereof |
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| CN202110428685.XA CN113136083A (en) | 2021-04-21 | 2021-04-21 | Composite electromagnetic shielding material for low-frequency wave band and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113999472A (en) * | 2021-11-23 | 2022-02-01 | 苏州聚冠复合材料有限公司 | Self-generating free perovskite polymer resin material and preparation method thereof |
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| CN102115558A (en) * | 2010-12-29 | 2011-07-06 | 四川大学 | High-conductivity polymer carbon nanotube composite material and micro-processing method thereof |
| CN102181116A (en) * | 2011-03-25 | 2011-09-14 | 杭州师范大学 | Carbon-nanotube-containing polymer nanocomposite and preparation method thereof |
| CN110294912A (en) * | 2019-06-30 | 2019-10-01 | 桂林理工大学 | A kind of preparation method of conductive polymer base composite electric magnetic shielding material |
| CN112159613A (en) * | 2020-10-10 | 2021-01-01 | 陈金锁 | Electromagnetic shielding metal plate coated with PMMA/graphene composite film and preparation method thereof |
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2021
- 2021-04-21 CN CN202110428685.XA patent/CN113136083A/en active Pending
Patent Citations (4)
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|---|---|---|---|---|
| CN102115558A (en) * | 2010-12-29 | 2011-07-06 | 四川大学 | High-conductivity polymer carbon nanotube composite material and micro-processing method thereof |
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| CN110294912A (en) * | 2019-06-30 | 2019-10-01 | 桂林理工大学 | A kind of preparation method of conductive polymer base composite electric magnetic shielding material |
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Non-Patent Citations (2)
| Title |
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| WENTAO CAO，ETAL.: ""Ultrathin and Flexible CNTs/MXene/Cellulose Nanofibrils Composite Paper for Electromagnetic Interference Shielding"", 《NANO-MICOR LETTERS》 * |
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Cited By (1)
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| CN113999472A (en) * | 2021-11-23 | 2022-02-01 | 苏州聚冠复合材料有限公司 | Self-generating free perovskite polymer resin material and preparation method thereof |
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