Ultra-light efficient electromagnetic shielding composite material and preparation method thereof

A composite material and raw material technology, applied in shielding materials, magnetic field/electric field shielding, carbon preparation/purification, etc., can solve the problems of secondary pollution of electromagnetic waves, high reflectivity, etc., and achieves less cellulose addition and excellent shielding performance. , the effect of low cellulose addition

Pending Publication Date: 2020-07-28
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these electromagnetic shielding materials with high conductivity have high reflectivity to electromagnetic waves, which easily cause secondary pollution of electromagnetic waves

Method used

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  • Ultra-light efficient electromagnetic shielding composite material and preparation method thereof
  • Ultra-light efficient electromagnetic shielding composite material and preparation method thereof
  • Ultra-light efficient electromagnetic shielding composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Embodiment 1 Preparation of electromagnetic shielding airgel of the present invention

[0045] Raw material bacterial cellulose (BC) was purchased from Guilin Qihong Technology Co., Ltd.; 2-methylimidazole (2-MI, 98%), cobalt nitrate hexahydrate (Co(NO 3 ) 2 ·6H 2 O, 98%) and potassium hydroxide (KOH, >85%) were purchased from Aladdin.

[0046] 1. Synthesis of BC@ZIF-67 airgel

[0047] Pretreatment of bacterial cellulose (BC): BC (1.601 g) was soaked in 1% (mg / mL) KOH aqueous solution at 70°C for 5 hours, and then washed with deionized water.

[0048] Self-assembly: Add the pretreated BC to 40mL containing 2mmol (0.582g) Co(NO 3 ) 2 ·6H 2 O aqueous solution, stirred at 25 ° C for 6h. Then, 60 mL of an aqueous solution containing 1.64 g of 2-MI was added dropwise under stirring, and mixed well. After continuing to stir for 2 hours, it was allowed to stand at 25 °C for 18 hours for undisturbed aging. Then the liquid was removed, the remaining system was washed 3 ...

experiment example 1

[0056] Experimental Example 1 Structural Characterization

[0057] 1. Experimental method

[0058] The CNF@Co / C airgel prepared in Example 1 was tested; the raw material bacterial cellulose (BC), the CNF airgel prepared in Comparative Example 1, and the metal-organic framework material ZIF- 67. The intermediate product BC@ZIF-67 airgel prepared in Example 1 was used as a control.

[0059] Scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), transmission electron microscopy-energy spectroscopy (TEM-EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction were performed on the samples respectively. (XRD) test to characterize the sample structure.

[0060] 2. Experimental results

[0061] SEM results such as figure 2 As shown in B~G, the TEM results are as follows image 3 As shown in A, the HRTEM results are as follows image 3 As shown in B~3D, the TEM-EDS results are as f...

experiment example 2

[0064] Experimental Example 2 Thermal Stability Characterization

[0065] 1. Experimental method

[0066] The CNF@Co / C airgel prepared in Example 1 was taken for testing; the CNF airgel prepared in Comparative Example 1 was used as a control.

[0067] The samples were subjected to thermogravimetric analysis (TG) with a thermogravimetric analyzer (TG 209F1, NETZSCH, Germany). The test conditions were nitrogen atmosphere, the test temperature range was 30-800°C, and the heating rate was 10°C / min.

[0068] 2. Experimental results

[0069] Such as Figure 5 As shown, it can be seen that the CNF@Co / C airgel prepared in the present invention has excellent thermal stability.

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Abstract

The invention relates to an ultra-light efficient electromagnetic shielding composite material and a preparation method thereof. The aerogel composite material is obtained by taking cellulose, a cobalt salt containing Co <2+> and an imidazole derivative as raw materials to prepare aerogel and then performing carbonization treatment. The mass of the cellulose accounts for 20-45% of the total mass of the cellulose, the cobalt salt containing Co <2+> and the imidazole derivative. The density of the aerogel composite material is as low as 0.023 gcm<3>, the shielding effectiveness under unit density is high, the average absorption coefficient of electromagnetic waves exceeds 0.77, meanwhile, the requirements of light weight, excellent electromagnetic interference shielding performance and internal absorption as a main shielding mechanism are met, secondary reflection pollution of electromagnetic waves caused by reflection can be effectively avoided, the problem that secondary reflection pollution is possibly caused by most electromagnetic shielding materials in the prior art is solved, and the electromagnetic shielding material has very wide application prospects in the fields of military equipment, space flight and aviation and civil electronic equipment.

Description

technical field [0001] The invention belongs to the field of electromagnetic shielding, and in particular relates to an ultra-light and high-efficiency electromagnetic shielding composite material and a preparation method thereof. Background technique [0002] Due to the rapid development of wireless communication and high-frequency electronic equipment, electromagnetic (EM) radiation not only produces non-negligible interference to high-sensitivity electromagnetic equipment, but also seriously endangers human health. Therefore, electromagnetic interference (EMI) shielding materials (referred to as Electromagnetic shielding materials) have gained more and more attention. [0003] Generally, the EMI shielding mechanism consists of three parts: Surface Reflection (SER), Internal Absorption (SEA) and Multiple Reflection (SEM). The EMI shielding mechanism of most existing electromagnetic interference shielding materials is mainly based on surface reflection, but reflection is l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/15C01B32/05B22F9/16H05K9/00
CPCC01B32/15C01B32/05B22F9/16H05K9/009B22F2009/165
Inventor 邹华维费洋陈洋雷雁洲
Owner SICHUAN UNIV
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