CN105802452A - A kind of graphene composite coating, graphene composite coating and preparation method thereof - Google Patents

Abstract

The invention provides a graphene composite paint, which is composed of resin, graphene, an aniline oligomer, a dispersion medium, and a paint assistant. In the graphene composite paint, the mass percentage of graphene is 0.01%-5%, and the graphene is uniformly dispersed in the resin by forming a Pi-Pi bond with the aniline oligomer. The invention also provides a preparation method of the graphene composite coating and the graphene composite coating.

Description

A kind of graphene composite coating, graphene composite coating and preparation method thereof

technical field

The invention relates to an anti-corrosion coating and an anti-corrosion coating, in particular to a graphene-based graphene composite coating, a graphene composite coating and a preparation method thereof.

Background technique

Anti-corrosion coatings refer to paints and coatings that can prevent corrosion of metals. In recent years, the country has been increasing investment in seven-tenths of the earth's oceans. Anti-corrosion coatings have become an important new force in the field of coatings. Anti-corrosion coatings are playing an increasingly important role and have promising development prospects. The current common anti-corrosion coatings include epoxy resin coatings, phenolic epoxy coatings, polyurethane anti-corrosion coatings, etc. Such coatings generally use high-molecular polymers or resins, which will leave micropores during the film formation process. In actual use, the corrosive medium will gradually penetrate through the micropores, and then corrode the metal substrate.

Graphene, as a new type of carbon material, has attracted extensive research interest due to its excellent electronic conductivity, wear-resistance and anti-friction properties, and extremely high specific surface area. However, when graphene is directly added to polymers or resins, graphene is prone to agglomeration due to π-π conjugation and van der Waals adsorption, and it is difficult to uniformly disperse in polymers or resins, resulting in micro Pores remain and the resulting coating is less protective.

Contents of the invention

For the deficiencies in the prior art, the main purpose of the present invention is to provide a kind of graphene composite coating, graphene composite coating and preparation method thereof, graphene is uniformly dispersed in resin in the described graphene composite coating, and the obtained The coating has good water penetration resistance and strong protection ability, and can be used as a heavy-duty anti-corrosion coating in relatively harsh corrosive environments such as ships and bridges.

The invention provides a graphene composite coating, which is composed of resin, graphene, aniline oligomer, dispersion medium and coating additives, and the mass percentage of graphene in the graphene composite coating is 0.01% to 5% %, the graphene is uniformly dispersed in the resin by forming π-π bonds with aniline oligomers.

Wherein, the mass ratio of the aniline oligomer to graphene is 1:10˜10:1.

Wherein, the diameter of the graphene is 5 μm˜50 μm.

Wherein, the aniline oligomer is one or a combination of aniline trimer, aniline tetramer, aniline pentamer and aniline hexamer.

Wherein, the dispersion medium is one or a combination of toluene, xylene, acetone, tetrahydrofuran, ethanol and dimethyl sulfoxide.

Wherein, the resin is one or a combination of epoxy resin, acrylic resin, polyurethane resin, acrylic polyurethane resin and amino resin.

Wherein, the coating additive includes anti-settling agent, defoamer and leveling agent, and the anti-settling agent is one or a combination of fumed silica, polyamide wax and organic bentonite, and the defoamer is One or a combination of simethicone oil, ether ester compound, modified mineral oil, polyoxyethyl glycerol ether, small molecular metal organic compound and modified silicone polymer, and the leveling agent is butyl glycol ether , Acetate butyl cellulose, polyacrylates, silicone oil, hydroxymethyl cellulose, polydimethylsilane, polymethylphenylsiloxane and modified organosilicon compounds, or one or a combination thereof.

The present invention also provides a preparation method of graphene composite coating, which comprises the following steps: dispersing aniline oligomer and graphene in a dispersion medium, mixing aniline oligomer and graphene uniformly and mixing aniline oligomer and graphene Forming π-π bonds between the graphenes to obtain a graphene dispersion; providing a resin, adding the graphene dispersion to the resin and mixing uniformly to obtain a mixture A; adding a coating additive to the mixture A, A graphene composite coating is obtained, wherein the graphene accounts for 0.01% to 5% by mass in the graphene composite coating.

The present invention also provides a graphene composite coating, which is composed of resin, graphene, aniline oligomers and coating additives, and the mass percentage of graphene in the graphene composite coating is 0.01% to 5% %, the graphene is uniformly dispersed in the resin by forming π-π bonds with aniline oligomers.

Wherein, the mass percentage of the resin in the graphene composite coating is 80% to 95%, the mass percentage of the aniline oligomer is 0.01% to 5%, and the coating additives account for The mass percentage is 1% to 10%.

Compared with the prior art, in the graphene composite coating provided by the present invention, the dispersibility and chemical stability of graphene are greatly improved by modifying the surface of graphene through aniline oligomers, so that the Graphene is evenly dispersed in the resin, and graphene has good hydrophobic properties, so in the application process, it can effectively inhibit the adsorption of water molecules on the surface of the formed graphene composite coating. At the same time, graphene has a two-dimensional sheet structure, which is uniformly dispersed in the coating. After forming a graphene composite coating, graphene can be stacked layer by layer to form a dense insulating layer, so small molecules corrode the medium (water molecules, chlorine, etc.) Ions, etc.) are difficult to pass through this dense insulating layer, which plays a prominent role in physical isolation. That is, the prepared graphene composite coating has good water penetration resistance, strong protection ability, and excellent anti-corrosion effect. Moreover, the graphene composite coating does not contain heavy metal elements such as In and Sn, and will not cause the problem of heavy metal pollution. The preparation method of the graphene composite coating provided by the present invention can obtain the graphene composite coating with good dispersibility and chemical stability through the innovation of the preparation process, the preparation process is simple, the cost is low, and it is beneficial to industrialization.

Description of drawings

Fig. 1 is a schematic diagram of the synthetic process of the aniline trimer of the present invention.

Fig. 2 is the photo of graphene dispersion liquid (right) described in embodiment 1 and untreated graphene after toluene dispersion (left).

Fig. 3 is the transmission electron micrograph of the graphene dispersion liquid described in embodiment 1.

Figure 4a is a photo of the surface morphology of the pure polyurethane coating in Comparative Example 2 after 500 hours of salt spray test.

Figure 4b is a photograph of the surface morphology of the graphene composite coating obtained in Example 3 after a salt spray test for 500 hours.

Figure 5a is an impedance complex plane view of the AC impedance spectrum of the epoxy resin coating of Comparative Example 1 soaked in 3.5wt% NaCl solution for 8 days.

Figure 5b is a Bode plot of the AC impedance spectrum of the epoxy resin coating of Comparative Example 1 soaked in 3.5 wt% NaCl solution for 8 days.

Fig. 5c is an impedance complex plane view of the AC impedance spectrum of the graphene composite coating obtained in Example 2 soaked in 3.5wt% NaCl solution for 8 days.

Figure 5d is a Bode plot of the AC impedance spectrum of the graphene composite coating obtained in Example 2 soaked in 3.5 wt% NaCl solution for 8 days.

Fig. 6 is the polarization curve of the graphene composite coating (corresponding to the solid line) obtained in Example 2 and the epoxy resin coating (corresponding to the dotted line) of Comparative Example 1 soaked in 3.5wt% NaCl solution for 8 days.

Fig. 7 is the graphene composite coating (corresponding to b curve) of embodiment 2 gained and comparative example 1 epoxy resin coating (corresponding to a curve) soaked in 3.5wt%NaCl solution lgQ _c -t ^1/2 in 8 days Curve and linear regression equation (where, Q _c is the capacitance of the coating, t is the test time).

Fig. 8 is the graphene composite coating (c curve) that embodiment 2 gains, comparative example 1 epoxy resin coating (corresponding b curve) and commercially available epoxy zinc-rich coating (corresponding a curve) in 3.5wt%NaCl AC impedance spectrum after soaking in the solution for 8 days.

detailed description

The graphene composite coating, graphene composite coating and preparation method thereof provided by the present invention will be further described below in conjunction with the accompanying drawings.

The embodiment of the present invention provides a preparation method of graphene composite coating. The method comprises the steps of:

Step (1): Disperse the aniline oligomer and graphene in a dispersion medium, mix the aniline oligomer and graphene uniformly and form a π-π bond between the aniline oligomer and graphene to obtain a graphene dispersion . The aniline oligomer has good solubility and can be dissolved in the dispersion medium. The aniline oligomer is used to modify the graphene. Specifically, since the benzene ring in the aniline oligomer is similar in structure to graphene, the aniline oligomer can form a π-π bond with graphene to achieve uniform mixing with graphene. It should be pointed out that the formation of π-π bonds between aniline oligomers and graphene is different from chemical grafting modification, which does not destroy the structure of graphene itself, and is also different from physical coating of graphite. Graphene polymers without sacrificing the properties of graphene. That is to say, modifying graphene with aniline oligomers only improves the dispersibility and stability of graphene without destroying the structure of graphene or reducing the original properties of graphene.

It can be understood that the graphene can be uniformly dispersed by high-speed stirring, ultrasonic, ball milling and/or sand milling dispersion methods, and the graphene and aniline oligomers can be further uniformly mixed.

The structure of the graphene is not limited, and it includes graphene nanosheets, graphene microsheets, graphene nanobelts, few-layer graphene (2-5 layers), multi-layer graphene (2-9 layers), graphene quantum dots and derivatives of these graphene-like materials). The definition of the graphene material can be found in the document "All in the graphene family—A recommended nomenclature for two-dimensional carbon materials". The graphene material can also be selected from materials with a thickness≤20nm, more preferably, a thickness≤10nm. In this embodiment, the thickness of the graphene material is preferably ≤3nm, and the thinner the graphene material, the better the flexibility and the easier it is to process. The preparation method of the graphene material is not limited, and it can be prepared by using graphene products well known to those skilled in the art or by conventional preparation methods. The graphene material of the present invention is preferably a graphene product provided by Ningbo Moxi Technology Co., Ltd. The graphene material can be selected from graphene materials prepared by thermal expansion of graphene oxide prepared by any one of chemical oxidation methods such as Brodie method, Hummers method or Staudenmaier method. Graphene materials prepared by mechanical exfoliation, liquid phase exfoliation or electrochemical exfoliation can also be selected. The graphene has a diameter of 5 μm˜50 μm. The aniline oligomer is one or a combination of aniline trimer, aniline tetramer, aniline pentamer and aniline hexamer. Please refer to Figure 1 for the structural formula of the aniline trimer. The dispersion medium is one or more mixed solvents of toluene, xylene, acetone, tetrahydrofuran, ethanol and dimethyl sulfoxide. The mass ratio of the aniline oligomer to graphene is 1:10˜10:1. Preferably, the mass ratio of the aniline oligomer to graphene is 2:1˜1:1.

Step (2): providing a resin, adding the graphene dispersion into the resin and mixing uniformly to obtain a mixture A. The graphene dispersion liquid can be uniformly dispersed in the resin by high-speed stirring, ultrasonic, ball milling and/or sand milling dispersion methods, and the graphene can be further uniformly dispersed in the resin. The resin is one or a combination of epoxy resin, acrylic resin, polyurethane resin, acrylic polyurethane resin and amino resin.

Step (3): adding a coating additive to the mixture A to obtain a graphene composite coating. The coating additives include anti-settling agents, defoamers and leveling agents. The anti-settling agent is one or a combination of fumed silica, polyamide wax and organic bentonite. The defoaming agent is one or a combination of simethicone, ether ester compound, modified mineral oil, polyoxyethyl glyceryl ether, small molecule metal organic compound and modified silicone polymer. The leveling agent is ethylene glycol butyl ether, cellulose acetate, polyacrylate, silicone oil, hydroxymethyl cellulose, polydimethylsilane, polymethylphenylsiloxane and modified organosilicon compound one or a combination of. It can be understood that the graphene composite coating can also include a curing agent. The curing agent can be polyamide, which is used to accelerate the curing process of the graphene composite coating.

The mass percentage of the graphene in the obtained graphene composite paint is 0.01%-5%, preferably 0.2%-0.5%.

The present invention also provides a graphene composite coating prepared by the method. The graphene composite coating is composed of resin, graphene, aniline oligomer, dispersion medium and coating additives. The mass percentage of the graphene in the graphene composite paint is 0.01%-5%. The graphene is uniformly dispersed in the resin by forming π-π bonds with aniline oligomers.

The present invention also provides a graphene composite coating prepared by using the above graphene composite coating. Specifically, the above-mentioned graphene composite coating is coated on the substrate by scraping, roller coating, etc., and the graphene composite coating is formed after the dispersion medium in the graphene composite coating is volatilized. The graphene composite coating is composed of resin, graphene, aniline oligomers and coating additives. The mass percentage of the graphene in the graphene composite coating is 0.01%-5%. The graphene is uniformly dispersed in the resin by forming π-π bonds with aniline oligomers. The mass percentage of the resin in the graphene composite coating is 80% to 95%, the mass percentage of the aniline oligomer is 0.01% to 5%, and the mass percentage of the coating additive 1% to 10%.

In the graphene composite coating provided by the present invention, the dispersibility and chemical stability of graphene are greatly improved by modifying the surface of graphene through aniline oligomers, so that the graphene is uniformly dispersed in the Among the resins, graphene has good hydrophobic properties, so it can effectively inhibit the adsorption of water molecules on the surface of the formed graphene composite coating during the application process. At the same time, graphene has a two-dimensional sheet structure, which is uniformly dispersed in the coating. After forming a graphene composite coating, graphene can be stacked layer by layer to form a dense insulating layer, so small molecules corrode the medium (water molecules, chlorine, etc.) Ions, etc.) are difficult to pass through this dense insulating layer, which plays a prominent role in physical isolation. That is, the prepared graphene composite coating has good water penetration resistance, strong protection ability, and excellent anti-corrosion effect. Moreover, the graphene composite coating does not contain heavy metal elements such as In and Sn, and will not cause the problem of heavy metal pollution. The preparation method of the graphene composite coating provided by the present invention can obtain the graphene composite coating with good dispersibility and chemical stability through the innovation of the preparation process, the preparation process is simple, the cost is low, and it is beneficial to industrialization.

For further describing the present invention, below is the preparation method of described graphene composite coating, graphene composite coating, the specific embodiment under different parameters:

Example 1:

1.0 g of aniline trimer (see Figure 1 for the synthesis process) and 1.0 g of graphene (purchased from Ningbo Moxi Technology Co., Ltd.) were dispersed in 1.0 L of toluene solution, and ultrasonically dispersed for 1 hour to obtain a graphene dispersion. The content of graphene in toluene after modified by aniline trimer reaches 1g/L. The comparative effect of the graphene dispersion and untreated graphene after toluene dispersion is shown in Figure 2. The transmission electron micrograph of the graphene dispersion is shown in FIG. 3 . It can be seen from Fig. 2 and Fig. 3 that graphene can be uniformly dispersed in toluene after being modified by aniline trimer, and graphene in the graphene dispersion liquid has a sheet-like structure.

The graphene dispersion was added to 45 g of epoxy resin (model E44, purchased from Jiangsu Wujiang Heli Resin Factory), and mixed to obtain mixture A. Then add 2g leveling agent, 4g defoamer, 2g anti-settling agent and 45g polyamide curing agent to the mixture A in sequence, and stir evenly to obtain the graphene composite coating.

Example 2:

2.0 g of aniline tetramer and 1.0 g of graphene were dispersed in 1.0 L of toluene solution, and ultrasonically dispersed for 1 hour to obtain a graphene dispersion. The content of graphene in toluene after modified by aniline tetramer reached 1g/L.

Add the graphene dispersion to 46g epoxy resin ((model is E44, purchased from Jiangsu Wujiang Heli Resin Factory), mix to obtain mixture A. Then add 1g leveling agent, 1g Defoamer, 1g anti-settling agent and 46g polyamide curing agent are stirred evenly to obtain the graphene composite coating.

The obtained graphene composite coating is coated on a carbon steel substrate, and after the toluene volatilizes, the graphene composite coating is obtained.

In order to compare the experimental effects, the epoxy resin coating of Comparative Example 1 was also prepared. The preparation method of the epoxy resin coating described in Comparative Example 1 is the same as in Example 2, except that no graphene dispersion is added.

The graphene composite coating described in Example 2 and the epoxy resin coating of Comparative Example 1 were tested for anti-corrosion performance. Specifically, soak the graphene composite coating and the epoxy resin coating of Comparative Example 1 in 3.5wt% NaCl solution for 8 days, and then use Shanghai Chenhua CHI660E electrochemical workstation to obtain the graphene composite coating respectively and AC impedance spectra (see Figure 5a to Figure 5d) and potentiodynamic polarization curves (see Figure 6) of the epoxy coating. It can be seen from Fig. 5a to Fig. 5d and Fig. 6 that the impedance of the graphene composite coating is larger than that of the epoxy resin coating. After soaking for 8 days, the self-corrosion current density of the graphene composite coating was 5.23nA·cm ^-2 , while that of the epoxy resin coating was 158nA·cm ^-2 . This shows that the graphene modified by the aniline oligomer can be uniformly dispersed in the resin, thereby greatly improving the anti-corrosion performance of the graphene composite coating.

The graphene composite coating described in Example 2 and the epoxy resin coating of Comparative Example 1 were tested for water penetration resistance. Specifically, by fitting the AC impedance value, plot lgQ _c (Qc is coating capacitance) against t ^1/2 to obtain FIG. 7 . Through linear fitting, the linear regression equations of epoxy resin coating and graphene composite coating can be obtained respectively, and then the diffusion coefficients of epoxy resin coating and graphene composite coating are calculated to be 6.35×10 ^-11 m ² /d and 9.1×10 ^-12 m ² /d. This shows that the modified graphene modified by aniline oligomer can be uniformly dispersed in the resin, thereby slowing down the diffusion speed of water molecules in the graphene composite coating.

With graphene coating and pure epoxy coating, commercially available epoxy zinc-rich coating is in 3.5wt%NaCl solution, by comparing the alternating current impedance spectrogram (see Figure 8) after 8 days, it can be seen that graphene epoxy coating The anti-corrosion effect is the best.

Example 3:

1.5 g of aniline trimer and 1.5 g of graphene were dispersed in 1.0 L of toluene solution, and ultrasonically dispersed for 1 hour to obtain a graphene dispersion. The content of graphene in toluene after modified by aniline trimer reaches 1.5g/L.

The graphene dispersion was added to 90g polyurethane (purchased from Ningbo Feilun Paint Co., Ltd.), and mixed to obtain mixture A. Add 2g of leveling agent, 3g of defoamer, and 2g of anti-settling agent to the mixture A in sequence, and stir evenly to obtain a graphene composite coating.

The obtained graphene composite coating is coated on a carbon steel substrate, and after the toluene volatilizes, the graphene composite coating is obtained.

In order to compare the experimental results, a pure polyurethane coating of Comparative Example 2 was also prepared. The preparation method of the pure polyurethane coating described in Comparative Example 2 is the same as in Example 3, except that no graphene dispersion is added.

The graphene composite coating described in Example 3 and the pure polyurethane coating of Comparative Example 2 were tested for salt spray resistance. Specifically, the graphene composite coating and the pure polyurethane coating of Comparative Example 2 were respectively placed in a salt spray test chamber, taken out after 1000 hours, and photographed after drying at room temperature (see Figure 4a and Figure 4b). It can be seen from Figure 4a and Figure 4b that there are obvious corrosion pits on the surface of the pure polyurethane coating, but no obvious corrosion phenomenon occurs on the surface of the graphene composite coating.

Example 4:

1.5 g of aniline trimer and 2 g of graphene were dispersed in 1.0 L of toluene solution, and ultrasonically dispersed for 1 hour to obtain a graphene dispersion. The content of graphene in toluene after modified by aniline tetramer reaches 2g/L.

The graphene dispersion was added to 90 g of acrylic resin (purchased from Shandong Weifang Fule New Material Co., Ltd.), and mixed to obtain a mixture A. Add 2g of leveling agent, 2.5g of defoamer, and 2g of anti-sedimentation agent to the mixture A in sequence, and stir evenly to obtain a graphene composite coating.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. a Graphene composite coating, it is characterised in that it is low by resin, Graphene, aniline Polymers, disperse medium and coating additive composition, Graphene institute described in Graphene composite coating The mass percent accounted for is 0.01%～5%, and this Graphene is by forming π-π with oligomer of phenylamine Key and be dispersed in described resin.

Graphene composite coating the most according to claim 1, it is characterised in that described aniline is low Polymers is 1:10～10:1 with the mass ratio of Graphene.

Graphene composite coating the most according to claim 1, it is characterised in that described Graphene A diameter of 5 μm～50 μm.

Graphene composite coating the most according to claim 1, it is characterised in that described aniline is low Polymers is the one in aniline trimer, Tetraaniline, aniline pentamer, aniline six aggressiveness Or combination.

Graphene composite coating the most according to claim 1, it is characterised in that described dispersion is situated between Matter be the one in toluene, dimethylbenzene, acetone, oxolane, ethanol and dimethyl sulfoxide or Combination.

Graphene composite coating the most according to claim 1, it is characterised in that described resin is Epoxy resin, acrylic resin, polyurethane resin, acrylated polyurethane resin and amino resins In one or combination.

Graphene composite coating the most according to claim 1, it is characterised in that described coating helps Agent includes that anti-settling agent, defoamer and levelling agent, described anti-settling agent are aerosil, polyamides One in amine wax and organobentonite or combination, described defoamer is dimethicone, ether-ether Compound, modified mineral oil, polyoxyethanyl glycerin ether, little molecular metal Organic substance and modification have One in organosilicon polymer or combination, described levelling agent be butyl glycol ether, cellaburate, Polyacrylate, silicone oil, hydroxymethyl cellulose, polydimethylsiloxane, polymethyl-benzene base silicon One in oxygen alkane and modified organic silicon compound or combination.

8. a preparation method for Graphene composite coating, it comprises the following steps:

By oligomer of phenylamine and graphene dispersion in disperse medium, make oligomer of phenylamine and graphite Alkene mix homogeneously and between oligomer of phenylamine and Graphene formed pi-pi bond obtain graphene dispersion Liquid；

One resin is provided, in described resin, adds described graphene dispersing solution mix homogeneously, Obtain mixture A；

In described mixture A, add coating additive, obtain Graphene composite coating,

Wherein, described in described Graphene composite coating, mass percent shared by Graphene is 0.01%～5%.

9. a Graphene composite coating, it is characterised in that it is low by resin, Graphene, aniline Polymers and coating additive composition, quality hundred shared by Graphene described in Graphene composite coating Mark is 0.01%～5%, this Graphene by with oligomer of phenylamine formed pi-pi bond and dispersed In described resin.

Graphene composite coating the most according to claim 9, it is characterised in that multiple at Graphene Described in conjunction coating, the mass percent shared by resin is 80%～95%, described oligomer of phenylamine Shared mass percent is 0.01%～5%, and the mass percent shared by described coating additive is 1%～10%.