阅读说明：本技术 多壁碳纳米管/氧化物纳米杂化吸波材料及其制备方法 (Multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material and preparation method thereof ) 是由 吉小利 马勖凯 刘健 于 2019-09-29 设计创作，主要内容包括：本发明公开了多壁碳纳米管/氧化物纳米杂化吸波材料及其制备方法,其中制备的方法步骤如下：S1：多壁碳纳米管的炔基化；S2：纳米氧化物的叠氮化；S3：在氮气气氛中,将经炔基化修饰的多壁碳纳米管和叠氮化修饰的纳米氧化物加入到含有催化剂、配体及有机溶剂的混合体系中反应,反应结束后,过滤,用去离子水,丙酮洗涤,真空干燥即得。本发明的多壁碳纳米管/氧化物纳米杂化吸波材料,有效地克服了各组分的团聚和不均匀分散,制得的材料不仅稳定性好,密度低,且呈现吸波性能增强效应,具有较好的微波吸收性能,该材料制备采用点击化学的方法,操作简单易行,不需使用贵金属的催化,经济效益好,适用于工业化生产。(The invention discloses a multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material and a preparation method thereof, wherein the preparation method comprises the following steps: s1: alkynylating the multi-walled carbon nanotubes; s2: nitridizing the nano oxide; s3: and in a nitrogen atmosphere, adding the alkynyl-modified multi-walled carbon nanotube and the azide-modified nano oxide into a mixed system containing a catalyst, a ligand and an organic solvent for reaction, after the reaction is finished, filtering, washing with deionized water and acetone, and drying in vacuum to obtain the catalyst. The multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material effectively overcomes the agglomeration and uneven dispersion of all components, the prepared material has good stability and low density, shows wave-absorbing performance enhancing effect and has better microwave absorption performance, the preparation of the material adopts a click chemistry method, the operation is simple and easy, the catalysis of noble metal is not needed, the economic benefit is good, and the material is suitable for industrial production.)

1. The multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material is characterized by comprising the multi-walled carbon nanotube and nano oxide.

2. The multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 1, wherein the nano oxide is nano SiO₂、TiO₂ZnO and SnO.

3. The preparation method of the multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 1 or 2, which comprises the following steps:

s1: alkynylating the multi-walled carbon nanotubes;

s2: nitridizing the nano oxide;

s3: and in a nitrogen atmosphere, adding the alkynyl-modified multi-walled carbon nanotube and the azide-modified nano oxide into a mixed system containing a catalyst, a ligand and an organic solvent for reaction, after the reaction is finished, filtering, washing with deionized water and acetone, and drying in vacuum to obtain the catalyst.

4. The preparation method of the multi-wall carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 3, wherein the method for alkynylating the multi-wall carbon nanotube in S1 comprises the following steps:

s11: acidification of multi-wall carbon nanotubes: adding a multi-walled carbon nanotube and concentrated nitric acid into a reaction container, immediately putting the multi-walled carbon nanotube and concentrated nitric acid into an oil bath pot after ultrasonic treatment for 1-3h, adding a magnetic stirrer, carrying out reflux reaction for 4-10h at 60-70 ℃, carrying out suction filtration after the reaction is finished, washing the multi-walled carbon nanotube to be neutral by deionized water, and then drying the multi-walled carbon nanotube in a drying oven at 70-90 ℃ for 12-24h to obtain an acidified multi-walled carbon nanotube;

s12: acyl chlorination of multi-wall carbon nanotubes: in a reaction vesselAdding SOCl₂And the acidified multi-walled carbon nano-tube in the S11, adding a magnetic stirrer, performing ultrasonic treatment for 15-25min, putting the mixture into an oil bath pot, performing reflux reaction at 60-80 ℃ for 12-24h, and performing suction filtration to remove SOCl after the reaction is finished₂Obtaining acyl chlorinated multi-walled carbon nano-tubes;

s13: preparation of alkynylated MWCNTS: adding the acyl chlorinated multi-walled carbon nanotube in S12 into a reaction container, then adding dichloromethane to disperse the nanotube, then adding anhydrous triethylamine, sealing the container by using a sealing film, placing the container into an ice water bath to cool to 0 ℃, slowly dropwise adding 3-5mL of 3-butyn-2-ol within 60-120min, continuing to react at 0 ℃ for 30-90min after dropwise adding, then reacting at room temperature for 12-24h, performing suction filtration after the reaction is finished to remove unreacted substances and byproducts, washing with dichloromethane, performing centrifugal separation with deionized water and dichloromethane after the washing is finished, repeating for 3 times, and then performing vacuum drying at 70-90 ℃ to obtain alkynyl MWCNTs;

preferably, the mass volume ratio of the multi-wall carbon nanotubes in the S11 to the concentrated nitric acid is 1g:100-150 ml;

preferably, the acidified multi-walled carbon nanotubes and SOCl in S12₂The mass volume ratio of the (B) is 1g:20-25 ml;

preferably, the mass-to-volume ratio of the acyl-chlorinated multi-walled carbon nanotubes, the dichloromethane for dispersing the substrate and the anhydrous triethylamine in the S13 is 1g to 20ml to 10 ml.

5. The preparation method of the multi-wall carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 3, wherein the step of azidation of the nano oxide in S2 is as follows:

s21: dissolving nano oxide in toluene, performing ultrasonic dispersion for 1-3h, adding KH560, reacting at 85-95 ℃, cooling to room temperature after the reaction is finished, performing suction filtration, extracting the obtained solid for 24-48h by using toluene as a solvent, and performing vacuum drying to obtain white oxide-KH 560;

s22: dissolving the oxide-KH 560 in S21 in a mixed solvent of methanol and water, and adding NaN₃And NH₄Cl, stirring and mixingThen reacting for 12-24h at 50-90 ℃ under the protection of nitrogen. After the reaction is finished, carrying out suction filtration, washing for many times, and carrying out vacuum drying to obtain white azide-modified nano oxide;

preferably, the mass ratio of the nano oxide to the KH560 in the S21 is 10-40: 1;

preferably, the volume ratio of methanol to water in S22 is 6-10:1, the oxide is-KH 560, the mixed solvent and NaN₃The mass-volume ratio of the NaN to the NaN is 4g to 100ml to 0.5-1g₃And NH₄The mass ratio of Cl is 1: 0.05-0.1.

6. The preparation method of the multi-wall carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 3, wherein the mass ratio of the multi-wall carbon nanotube modified by alkynylation and the nano oxide modified by azidation in S3 is 1: 0.5-2.

7. The preparation method of the multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 3, wherein the reaction conditions in S3 are as follows: the temperature is 30-45 ℃ and the time is 24-48 h.

8. The method for preparing the multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material according to claim 3, wherein the catalyst in S3 is a Cu (I) catalyst system: reduction of CuSO with CuI, copper or copper wire₄System, Cu (I) (PPh)₃)₃Br and sodium ascorbate are used for reducing one of CuSO4 systems, and the dosage of Br and sodium ascorbate is 5-10 mol% of azide oxide.

9. The preparation method of the multi-wall carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 2, wherein the ligand in the S3 is triethylamine, and the amount of the ligand is 10-20 mol% of azide oxide.

10. The preparation method of the multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material as claimed in claim 2, wherein the organic solvent in S3 is one or more selected from tetrahydrofuran, N-dimethylformamide, hexamethylphosphoric triamide and an ethanol-water mixed system, and the dosage ratio of the organic solvent to the azide oxide is 10-20mL:1 mmol.

Technical Field

The invention relates to the technical field of electromagnetic composite materials, in particular to a multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material and a preparation method thereof.

Background

With the development of military stealth technology and the wide application of electronic equipment such as local area networks, computers, mobile phones and the like, the importance of microwave absorbing materials (absorbing materials for short) is increasing day by day. The research of the wave-absorbing material has immeasurable effect on military affairs and civil affairs, so that more and more researchers obtain high attention. At present, the prepared microwave absorbing material still has the problems of narrow absorption band, low absorption strength, non-ideal physical comprehensive performance, complex preparation process, interface compatibility and the like. Therefore, the research and development of novel materials with wide absorption frequency band, strong wave-absorbing capability, light weight, thin thickness and good physical and mechanical properties is still the key point of the research of the microwave stealth materials.

The carbon nano tube has the advantages of heat resistance, corrosion resistance, good heat transfer and electric conductivity, low density and the like, and can become a good electromagnetic wave absorption material due to the high specific surface area, a large number of dangling bonds on the surface and the macroscopic quantum tunnel effect. However, since the carbon-based absorbents have a large dielectric constant, they have disadvantages such as poor impedance matching characteristics, narrow absorption band, and poor performance when used alone. The form of single loss is a major cause of poor capacity of carbon nanotubes.

Disclosure of Invention

Based on the technical problems existing in the background technology, the invention provides a multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material and a preparation method thereof, the material has the advantages that two components of the material are connected by a covalent bond, the material has good interface compatibility and stability, good microwave absorption performance and low density, the material is prepared by a click chemistry method, the operation is simple and easy, the catalysis of noble metal is not needed, the economic benefit is good, the material is suitable for industrial production, and the material can be widely applied to the fields of electromagnetic absorption, electromagnetic shielding and the like.

The invention provides a multiwalled carbon nanotube/oxide nano hybrid wave-absorbing material, which comprises a multiwalled carbon nanotube and a nano oxide.

Preferably, the nano oxide is nano SiO₂、TiO₂ZnO and SnO.

The preparation method of the multiwalled carbon nanotube/oxide nano hybrid wave-absorbing material provided by the invention comprises the following steps:

s1: alkynylating the multi-walled carbon nanotubes;

s2: nitridizing the nano oxide;

s3: and in a nitrogen atmosphere, adding the alkynyl-modified multi-walled carbon nanotube and the azide-modified nano oxide into a mixed system containing a catalyst, a ligand and an organic solvent for reaction, after the reaction is finished, filtering, washing with deionized water and acetone, and drying in vacuum to obtain the catalyst.

Preferably, the method for alkynylating multi-walled carbon nanotubes in S1 comprises the following steps:

s11: acidification of multi-wall carbon nanotubes: adding a multiwalled carbon nanotube and 65% concentrated nitric acid by mass into a reaction vessel, immediately putting into an oil bath pot after ultrasonic treatment is carried out for 1-3h, adding a magnetic stirrer, carrying out reflux reaction at 60-70 ℃ for 4-10h, carrying out suction filtration after the reaction is finished, washing with deionized water to be neutral, and then drying in an oven at 70-90 ℃ for 12-24h to obtain an acidified multiwalled carbon nanotube;

s12: acyl chlorination of multi-wall carbon nanotubes: adding SOCl into a reaction vessel₂And the acidified multi-walled carbon nanotubes and SOCl in the S11₂Adding magnetic stirrer, ultrasonic treating for 15-25min, placing in oil bath, reflux reacting at 60-80 deg.C for 12-24 hr, and vacuum filtering to remove SOCl₂Obtaining acyl chlorinated multi-walled carbon nano-tubes;

s13: preparation of alkynylated MWCNTS: adding the acyl chlorinated multi-walled carbon nanotube in S12 into a reaction container, then adding dichloromethane to disperse the nanotube, then adding anhydrous triethylamine, sealing the container by using a sealing film, placing the container into an ice water bath to cool to 0 ℃, slowly dropwise adding 3-5mL of 3-butyn-2-ol within 60-120min, continuing to react at 0 ℃ for 30-90min after dropwise adding, then reacting at room temperature for 12-24h, performing suction filtration after the reaction is finished to remove unreacted substances and byproducts, washing with dichloromethane, performing centrifugal separation with deionized water and dichloromethane after the washing is finished, repeating for 3 times, and then performing vacuum drying at 70-90 ℃ to obtain alkynyl MWCNTs;

preferably, the mass volume ratio of the multi-wall carbon nanotubes in the S11 to the concentrated nitric acid is 1g:100-150 ml;

preferably, the acidified multi-walled carbon nanotubes and SOCl in S12₂The mass volume ratio of the (B) is 1g:20-25 ml;

preferably, the mass-to-volume ratio of the acyl-chlorinated multi-walled carbon nanotubes in S13, the dichloromethane for dispersing the substrate and the anhydrous triethylamine is 0.5-1g:20ml:10 ml.

Preferably, the nitridization method of the nano-oxide in S2 comprises the following steps:

s21: dissolving nano oxide in toluene, performing ultrasonic dispersion for 1-3h, adding KH560, reacting at 85-95 ℃, cooling to room temperature after the reaction is finished, performing suction filtration, extracting the obtained solid for 24-28h by using toluene as a solvent, and performing vacuum drying to obtain white oxide-KH 560;

s22: dissolving the oxide-KH 560 in S21 in a mixed solvent of methanol and water, and adding NaN₃And NH₄And Cl, stirring and mixing, and reacting for 12-24h at 50-90 ℃ under the protection of nitrogen. After the reaction is finished, carrying out suction filtration, washing for many times, and carrying out vacuum drying to obtain white azide-modified nano oxide;

preferably, the mass ratio of the nano oxide to the KH560 in the S21 is 10-40: 1;

preferably, the volume ratio of methanol to water in S22 is 6-10:1, the oxide is-KH 560, the mixed solvent and NaN₃The mass-volume ratio of the NaN to the NaN is 4g to 100ml to 0.5-1g₃And NH₄The mass ratio of Cl is 1: 0.05-0.1.

Preferably, the mass ratio of the multi-walled carbon nano-tube subjected to alkynyl modification and the nano-oxide subjected to azide modification in S3 is 1: 0.5-2.

Preferably, the reaction conditions in S3 are: the temperature is 30-45 ℃ and the time is 24-48 h.

Preferably, the catalyst in S3 is a Cu (i) catalyst system: reduction of CuSO with CuI, copper or copper wire₄System, Cu (I) (PPh)₃)₃Br and sodium ascorbate are used for reducing one of CuSO4 systems, and the dosage of Br and sodium ascorbate is 5-10 mol% of azide oxide.

Preferably, the ligand in S3 is triethylamine, and the dosage is 10-20 mol% of the azide oxide.

Preferably, the organic solvent in S3 is selected from one or more of tetrahydrofuran, N-dimethylformamide, hexamethylphosphoric triamide and an ethanol-water mixed system, and the dosage ratio of the organic solvent to the azide oxide is 10-20mL:1 mmol.

Compared with the prior art, the invention has the beneficial technical effects that:

(1) according to the multi-walled carbon nanotube/oxide nano hybrid wave-absorbing material prepared by the invention, the oxide and the carbon nanotube are bonded by covalent bonds on a molecular level, so that the agglomeration and uneven dispersion of each component are effectively overcome, the prepared material has good interface compatibility and stability, the two components play a synergistic effect, a wave-absorbing performance enhancing effect is presented, the material has good microwave absorption performance, the maximum absorption strength can reach-53.68 dB under the thickness of 2.5mm, and the materials with different wave-absorbing performances can be obtained by adjusting the feed ratio;

(2) the preparation method is simple and easy to implement, has good economic benefit due to low-temperature reaction, and is suitable for industrial production.

Drawings

FIG. 1 is example 1 alkynylated MWCNTs and azido TiO₂XRD pattern of the prepared nano hybrid wave-absorbing material;

FIG. 2 depicts alkynylated MWCNTs and azido TiO of example 1₂SEM picture of the prepared nano hybrid wave-absorbing material;

FIG. 3 depicts alkynylated MWCNTs and azido TiO of example 1₂Reflection loss curve of prepared nano hybrid wave-absorbing materialA plot of variation with frequency;

FIG. 4 is the alkynylated MWCNTs and azido SiO of example 2₂XRD pattern of the prepared nano hybrid wave-absorbing material;

FIG. 5 is the alkynylated MWCNTs and azido SiO of example 2₂SEM picture of the prepared nano hybrid wave-absorbing material;

FIG. 6 is the alkynylated MWCNTs and azido SiO of example 2₂The change curve of the reflection loss curve of the prepared nano hybrid wave-absorbing material along with the frequency is shown in the figure.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples.