Ferrocenyl modified graphene oxide wave-absorbing coating as well as preparation method and application thereof

Abstract

The invention provides a ferrocenyl modified graphene oxide wave-absorbing coating, a preparation method and application, graphene oxide is subjected to surface modification with 1, 1 '-ferrocenedicarboxylic acid to prepare a ferrocenyl modified graphene oxide wave-absorbing agent, and then the ferrocenyl modified graphene oxide wave-absorbing agent and an epoxy resin system are used for preparing the ferrocenyl modified graphene oxide epoxy wave-absorbing coating. The prepared ferrocenyl modified graphene oxide wave-absorbing agent has good wave-absorbing performance, the ferrocenyl modified graphene oxide wave-absorbing agent is used for preparing an epoxy resin wave-absorbing coating, and the ferrocenyl group modified on the surface of the wave-absorbing agent can increase the compatibility of graphene oxide and an epoxy resin matrix and promote the dispersion effect; carboxyl introduced through the ferrocene derivative on the surface of the wave-absorbing agent can react with epoxy groups of epoxy resin, so that the binding force of the wave-absorbing agent and a coating matrix is improved. The ferrocenyl modified graphene oxide wave-absorbing agent and the ferrocenyl modified graphene oxide epoxy wave-absorbing coating prepared by the preparation method disclosed by the invention have good wave-absorbing performance.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials and relates to a ferrocene-based modified graphene oxide radar-absorbing coating, a preparation method and an application thereof. Background Art

[0002] With the advancement of science and technology, electromagnetic waves have been widely used in wireless communications, medical care, military defense, scientific research, etc., but electromagnetic waves will cause signal interference to surrounding instruments and meters, affect human health, and affect the concealment of important equipment. In order to reduce or eliminate the adverse effects of electromagnetic waves, the development of high-performance absorbing materials has become a focus of academic and industrial circles. Compared with other absorbing technologies, absorbing coatings have the advantages of simple preparation, easy use, easy maintenance, good adaptability, etc., and are one of the important research directions of absorbing technology.

[0003] Graphene has a two-dimensional layered structure, and has the advantages of excellent dielectric properties, good shielding properties, light weight, and chemical stability. It has good application prospects in radar-absorbing coatings. The various oxygen-containing functional groups and defects on its surface are conducive to the impedance matching and polarization effect of composite materials, thereby enhancing the electromagnetic shielding performance of composite materials.

[0004] Ferrocene is an organometallic compound with stable performance, can undergo electrophilic substitution reaction, and can be introduced into other materials through reactions between functional groups. Ferrocene-modified materials are beneficial to promote electron migration due to their redox properties. Studies have been conducted to introduce ferrocene into graphene oxide to form nanocomposites by non-covalent modification methods, and it has been found that the ferrocene group has a reversible single-electron oxidation potential, and the electronic structure of GO can enhance the response current of ferrocene (Karthick NA et al., Journal of Inorganic and Organometallic Polymers and Materials, 2018, 28 (3): 1021-1028). Gao et al. also studied ferrocene non-covalently modified graphene oxide (Gao Y, Hu G et al., Dalton Transactions, 2011, 40 (17): 4542-4547) and found that there is a strong π-π interaction between the carbon main body of graphene oxide layer and the metallocene molecule. Functional modification of graphene oxide can improve the dispersion stability of its sheets in various solvents, and at the same time improve the compatibility of its sheets with the polymer matrix (Lai Shuangquan et al., China Leather, 2018, 47(2): 22-27).

[0005] Epoxy resin is widely used in composite materials, adhesive materials and coatings due to its advantages of easy curing, strong adhesion, low shrinkage, excellent mechanical properties and good chemical stability. High-performance absorbing coatings can be prepared with epoxy resin as the matrix, which is suitable for various substrates and has good application prospects. To prepare high-performance ferrocene-modified graphene oxide absorbing coatings, it is necessary to improve the dispersibility of graphene oxide in epoxy resin and the binding force between modified graphene oxide and epoxy resin matrix. Summary of the invention

[0006] The first object of the present invention is to provide a ferrocene-modified graphene oxide radar absorbing coating.

[0007] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] The ferrocene-modified graphene oxide microwave absorbing coating is prepared from a ferrocene-modified graphene oxide microwave absorbing agent and an epoxy resin system;

[0009] The ferrocene-modified graphene oxide wave absorber is prepared by surface-modifying graphene oxide with 1,1'-ferrocene dicarboxylic acid and oxalyl chloride.

[0010] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0011] As a preferred technical solution of the present invention: the graphene oxide is surface-modified by hydroxylation.

[0012] As a preferred technical solution of the present invention: the hydroxyl content is 0.3-0.6 mmol / g.

[0013] As a preferred technical solution of the present invention: the ferrocene-modified graphene oxide absorber is prepared by the following method:

[0014] S1. Add 1,1'-ferrocenedicarboxylic acid, dichloromethane and pyridine into a reaction vessel and stir until completely dissolved, then slowly add oxalyl chloride, react at 20°C to 25°C for 0.5 hour, then heat to dichloromethane reflux state and react for 5 hours, remove the solvent in vacuo, then add petroleum ether with a boiling range of 60 to 90°C and reflux for 2 hours, filter while hot to obtain a filtrate, remove the solvent in vacuo, and dry to obtain 1,1'-ferrocenedicarboxylic acid chloride;

[0015] S2. Add the obtained 1,1'-ferrocene dicarbonyl chloride, graphene oxide, dichloromethane and triethylamine into a reaction container, stir to react, filter and wash after the reaction, and dry to obtain ferrocene-modified graphite oxide.

[0016] As a preferred technical solution of the present invention: in step S2, the mass ratio of the 1,1'-ferrocenyl dicarbonyl chloride to the graphene oxide is 3 to 12:1.

[0017] As a preferred technical solution of the present invention: in step S2, the graphene oxide is modified by surface hydroxylation.

[0018] As a preferred technical solution of the present invention: the hydroxyl content is 0.3-0.6 mmol / g.

[0019] The second object of the present invention is to provide a method for preparing a ferrocene-modified graphene oxide radar absorbing coating.

[0020] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0021] A method for preparing a ferrocene-based modified graphene oxide radar absorbing coating, the method is used to prepare the ferrocene-based modified graphene oxide radar absorbing coating as described above, and comprises the following steps:

[0022] The ferrocene-modified graphene oxide absorber is compounded with epoxy resin, defoamer, leveling agent and solvent by ball milling to form component A;

[0023] The epoxy curing agent is component B;

[0024] When using, mix component A and component B thoroughly.

[0025] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0026] As a preferred technical solution of the present invention: in component A, the epoxy resin is bisphenol A type epoxy resin;

[0027] In component B, the epoxy curing agent is a fatty amine curing agent.

[0028] As a preferred technical solution of the present invention: the ball milling time is 2 to 10 hours, and the rotation speed is 100 to 500 rpm.

[0029] Another object of the present invention is to provide an application of ferrocene-modified graphene oxide in the preparation of radar absorbing coatings.

[0030] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0031] Application of ferrocene-modified graphene oxide in the preparation of radar-absorbing coatings, wherein the ferrocene-modified graphene oxide is a ferrocene-modified graphene oxide radar-absorbing agent prepared by surface-modifying graphene oxide with 1,1'-ferrocenedicarboxylic acid and oxalyl chloride;

[0032] The microwave-absorbing coating is prepared from a ferrocene-modified graphene oxide microwave-absorbing agent and an epoxy resin system.

[0033] The present invention provides a ferrocene-modified graphene oxide wave absorbing coating, a preparation method and an application thereof. The present invention uses 1,1'-ferrocenedicarboxylic acid to perform surface modification on graphene oxide to prepare a ferrocene-modified graphene oxide wave absorbing agent, and then prepares a ferrocene-modified graphene oxide epoxy wave absorbing coating with an epoxy resin system. The ferrocene-modified graphene oxide wave absorbing agent prepared by the present invention has good wave absorbing performance. The ferrocene-modified graphene oxide wave absorbing agent is used to prepare an epoxy resin wave absorbing coating. The ferrocene group modified on the surface of the wave absorbing agent can increase the compatibility of graphene oxide with an epoxy resin matrix and promote the dispersion effect; the carboxyl group introduced on the surface of the wave absorbing agent through a ferrocene derivative can react with the epoxy group of the epoxy resin to improve its binding force with the coating matrix. The ferrocene-modified graphene oxide wave absorbing agent and the ferrocene-modified graphene oxide epoxy wave absorbing coating prepared by the present invention have good wave absorbing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The SEM image and SEM-EDS mapping diagram of the ferrocene-modified graphene oxide absorber, where Fe comes from the ferrocene group modified on the graphene surface. DETAILED DESCRIPTION

[0035] The following embodiments provide a more detailed description of the present invention, but the present invention is not limited thereto. A person skilled in the art may make several improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field.

[0036] Example 1

[0037] 15 g of dry 1,1'-ferrocenedicarboxylic acid was added to a round-bottom flask, and then 200 ml of dried dichloromethane and 12 ml of pyridine were added. Under argon protection, 15 ml of oxalyl chloride was slowly added dropwise. After reacting at 25°C for 0.5 hour, the reaction oil bath temperature was even increased to 50°C for 8 hours. The liquid component was removed by vacuuming, and 200 ml of petroleum ether with a boiling range of 60-90°C was added. The mixture was refluxed at an oil bath temperature of 90°C for 2 hours. The mixture was filtered through a sand core funnel while hot, and the petroleum ether was removed by vacuuming the obtained filtrate to obtain 1,1'-ferrocenedicarboxylic acid chloride.

[0038] Example 2

[0039] 1.5 g of surface hydroxylated graphene oxide (hydroxyl content of 0.4 mmol / g), 6 g of 1,1'-ferrocenyl dicarbonyl chloride, and 30 ml of dichloromethane were added to a three-necked flask, and argon was passed through. After ultrasonic dispersion for 15 minutes, it was heated to 50°C in an oil bath and stirred for 16 hours. After the reaction, dichloromethane was removed by vacuum filtration, and then washed with THF 3 to 4 times, washed with a large amount of deionized water 3 to 4 times, and dried in a vacuum drying oven at 50°C to constant weight to obtain a ferrocenyl-modified graphene oxide absorber. Due to the excess of 1,1'-ferrocenyl dicarbonyl chloride, the surface of the obtained ferrocenyl-modified graphene oxide has ferrocenyl formic acid groups. The characterization results are as follows: Figure 1 As shown, Figure 1 The SEM image and SEM-EDS mapping of the ferrocene-modified graphene oxide absorber, where Fe comes from the ferrocene group modified on the graphene surface, indicating that the ferrocene carboxylic acid group is grafted onto the graphene oxide. The maximum absorption performance of the ferrocene-modified graphene oxide absorber is about -23dB.

[0040] Example 3

[0041] 1 gram of surface hydroxylated graphene oxide (hydroxyl content of 0.4 mmol / g), 6 grams of 1,1'-ferrocenyl dicarbonyl chloride, and 30 milliliters of dichloromethane were added to a three-necked flask, argon protection, ultrasonic dispersion for 15 minutes, heated to 50°C in an oil bath, and stirred for 16 hours. After the reaction, dichloromethane was removed by vacuum filtration, then washed with THF 3 to 4 times, washed with a large amount of deionized water 3 to 4 times, and dried in a 50°C vacuum drying oven to constant weight to obtain a ferrocenyl-modified graphene oxide absorber. Due to the excess of 1,1'-ferrocenyl dicarbonyl chloride, the obtained ferrocenyl-modified graphene oxide surface has ferrocenyl formic acid groups. The maximum absorption performance of the ferrocenyl-modified graphene oxide absorber is about -25dB.

[0042] Example 4

[0043] 3 g of ferrocene-modified graphene oxide absorber, 7 g of epoxy resin (epoxy equivalent: 200.2 g / mol), 6 ml of solvent, 0.06 g of defoamer, and 0.07 g of leveling agent were mixed and ground and dispersed in a ball mill at a speed of 300 rpm for 3 h. The obtained component was used as component A of the absorbing coating.

[0044] Aliphatic amine curing agent (amine value: 189.9 mg KOH / g) is mixed with one quarter of the mass of solvent to form component B;

[0045] When used, component A and component B are mixed evenly in a mass ratio of 1:1 and then coated, and the temperature is raised to 180°C and cured for 20 minutes to obtain an absorbing coating. The surface of the ferrocene-modified graphene oxide has ferrocene carboxylic acid groups, which can react with the epoxy groups of the epoxy resin during the coating curing process to increase the interaction between it and the epoxy resin matrix. The obtained ferrocene-modified graphene oxide epoxy absorbing coating has good absorbing performance (maximum absorbing performance is about -16dB).

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Ferrocene-based modified graphene oxide radar absorbing coating, characterized in that: The ferrocene-based modified graphene oxide microwave absorbing coating is prepared from a ferrocene-based modified graphene oxide microwave absorbing agent and an epoxy resin system; The ferrocene-modified graphene oxide wave absorber is prepared by surface-modifying graphene oxide with 1,1'-ferrocene dicarboxylic acid and oxalyl chloride.

2. The ferrocene-modified graphene oxide radar absorbing coating according to claim 1, characterized in that: The graphene oxide is surface-modified by hydroxylation.

3. The ferrocene-modified graphene oxide radar absorbing coating according to claim 2, characterized in that: The hydroxyl content is 0.3-0.6 mmol / g.

4. The ferrocene-modified graphene oxide radar absorbing coating according to claim 1, characterized in that: The ferrocene-modified graphene oxide absorber is prepared by the following method: S1. Add 1,1'-ferrocenedicarboxylic acid, dichloromethane and pyridine into a reaction vessel and stir until completely dissolved, then slowly add oxalyl chloride, react at 20°C to 25°C for 0.5 hour, then heat to dichloromethane reflux state and react for 5 hours, remove the solvent in vacuo, then add petroleum ether with a boiling range of 60 to 90°C and reflux for 2 hours, filter while hot to obtain a filtrate, remove the solvent in vacuo, and dry to obtain 1,1'-ferrocenedicarboxylic acid chloride; S2. Add the obtained 1,1'-ferrocene dicarbonyl chloride, graphene oxide, dichloromethane and triethylamine into a reaction container, stir to react, filter and wash after the reaction, and dry to obtain ferrocene-modified graphite oxide.

5. The ferrocene-modified graphene oxide radar absorbing coating according to claim 4, characterized in that: In step S2, the mass ratio of the 1,1'-ferrocenyl dicarbonyl chloride to graphene oxide is 3 to 12:

1.

6. The ferrocene-modified graphene oxide radar absorbing coating according to claim 4, characterized in that: In step S2, the graphene oxide is surface-modified by hydroxylation.

7. A method for preparing a ferrocene-modified graphene oxide radar absorbing coating, characterized in that: The preparation method is used to prepare the ferrocene-modified graphene oxide radar absorbing coating according to any one of claims 1 to 3, and comprises the following steps: The ferrocene-modified graphene oxide absorber is compounded with epoxy resin, defoamer, leveling agent and solvent by ball milling to form component A; The epoxy curing agent is component B; When using, mix component A and component B thoroughly.

8. The preparation method according to claim 7, characterized in that: In component A, the epoxy resin is bisphenol A type epoxy resin; In component B, the epoxy curing agent is a fatty amine curing agent.

9. The preparation method according to claim 7, characterized in that: The ball milling time is 2 to 10 hours, and the rotation speed is 100 to 500 rpm.

10. Application of ferrocene-modified graphene oxide in the preparation of radar absorbing coatings, characterized in that: The ferrocenyl-modified graphene oxide is a ferrocenyl-modified graphene oxide absorber prepared by surface modification of graphene oxide with 1,1'-ferrocenedicarboxylic acid and oxalyl chloride; The microwave-absorbing coating is prepared from a ferrocene-modified graphene oxide microwave-absorbing agent and an epoxy resin system.

Images