CN112585222B

CN112585222B - Discrete graphene sheet coated with anti-corrosive material and anti-corrosive coating composition comprising discrete graphene sheet

Info

Publication number: CN112585222B
Application number: CN201980045222.6A
Authority: CN
Inventors: 孟繁君; 林怡君; 李晓燕; 文·Y·邱; 阿茹娜·扎姆; 张博增
Original assignee: Nanotek Instruments Inc
Current assignee: Nanotek Instruments Inc
Priority date: 2018-05-08
Filing date: 2019-05-08
Publication date: 2023-12-08
Anticipated expiration: 2039-05-08
Also published as: KR20200141519A; CA3099723A1; EP3790932A4; JP2021523864A; CN112585222A; JP7447021B2; WO2019217514A1; EP3790932A1

Abstract

There is provided a graphene-based coating suspension comprising a plurality of graphene sheets and a binder resin dissolved or dispersed in a liquid medium, a thin film coating of a corrosion-inhibiting pigment or a sacrificial metal being deposited on the graphene sheets, wherein the plurality of graphene sheets contains single or few layer graphene sheets selected from the group consisting of: a pristine graphene material having substantially zero% non-carbon elements or a non-pristine graphene material having from 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof. The present disclosure also provides a method for producing such a coating suspension. An object or structure at least partially coated with such a coating is also provided.

Description

Discrete graphene sheet coated with anti-corrosive material and anti-corrosive coating composition comprising discrete graphene sheet

Cross Reference to Related Applications

The present application claims priority from U.S. patent application Ser. No. 15/973,651 filed 5/8/2018 and U.S. patent application Ser. No. 15/973,656 filed 5/8/2018, the contents of each of which are incorporated herein by reference.

FIELD

The present disclosure relates generally to the field of corrosion resistant coatings, and more particularly to a coating composition implemented with graphene and a method of operating the same.

Background

Corrosion of metallic materials is a high cost problem. For example, corrosion causes problems with costs of 2% to 5% of the total annual domestic production (GDP) in the united states. Both ferrous metals (e.g., iron and steel) and nonferrous metals (e.g., aluminum, copper, etc.) can corrode. These metallic materials are commonly used in marine and offshore structures, bridges, containers, refineries, power plants, storage tanks, cranes, windmills, airports, petrochemical facilities, and the like.

The corrosion resistant coating protects the metal component from degradation by moisture, salt spray, oxidation, or exposure to various environmental or industrial chemicals. The corrosion protection coating can increase the protection of the metal surface and act as a barrier to prevent corrosive agents from contacting the metal substrate to be protected. In addition to corrosion protection, many coatings also provide improved wear resistance, non-tackiness, and chemical protection. The coating with corrosion protection properties ensures that the metal part has the longest possible lifetime.

As one example, corrosion protection coatings for protecting steel structures include zinc primers in which zinc is used as a conductive pigment to produce an anodic active coating. Zinc acts as a sacrificial anode material protecting the steel matrix that becomes the cathode. Corrosion resistance may depend on galvanic transfer of the zinc primer and the steel substrate remains galvanic protected as long as conductivity in the system is maintained and sufficient zinc is present to act as an anode. To meet these requirements, zinc primers are typically formulated to contain high loadings of zinc particles (e.g., up to 80% by weight zinc), and the zinc pigment particles in the zinc primer are tightly packed together. However, high zinc loadings mean that the difficulty of dispersing the solids in the liquid medium is great, it is difficult to apply the primer to the steel surface to be protected, the coating is too thick and dense, and the cost is high. Other coating systems for protecting other types of metal structures also have serious drawbacks.

Thus, it remains highly desirable to develop improved corrosion protection coatings. A particular object of the present disclosure is a new coating system that requires a smaller amount of anode or sacrificial material.

SUMMARY

The present disclosure provides a graphene-based coating suspension comprising a plurality of graphene sheets each having two opposite parallel surfaces (also referred to as primary surfaces), a thin film coating of a corrosion-inhibiting pigment or sacrificial metal (having a thickness from 0.5nm to 500 nm) applied to and covering at least 50% of the area of one of the two parallel surfaces, and a binder resin, dissolved or dispersed in a liquid medium, wherein the plurality of graphene sheets contains a single layer or few layer graphene sheets selected from: a pristine graphene material having substantially zero% non-carbon elements or a non-pristine graphene material having from 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof. Preferably, the graphene sheets have a weight fraction of from 0.1% to 30% based on the total coating suspension weight excluding the liquid medium. The non-pristine graphene material may have from 1% to 30% by weight of non-carbon elements selected from O, H, N, F, cl, br, I, B, P or combinations thereof.

In certain embodiments, the corrosion-inhibiting pigment or sacrificial metal is selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof. Such corrosion resistant materials form a thin coating deposited on one or both primary surfaces of the graphene sheets. Such thin coatings preferably have a thickness from 1nm to 100nm deposited on a single layer graphene sheet (0.34 nm thick) or a few layer graphene sheet (about 0.68nm to 3.4nm thick). Both the graphene sheets and the corrosion-resistant material coated on their surfaces are thin. Corrosion-resistant coating compositions containing these ultra-thin corrosion-resistant material coated graphene sheets are surprisingly more effective at protecting metal surfaces from corrosion than corresponding coating compositions in which individual graphene sheets and discrete particles of corrosion-resistant pigment or metal, respectively, are dispersed in a liquid medium to form a coating suspension.

The binder resin may preferably contain a resin selected from the group consisting of epoxy resins, polyurethane resins, urethane-urea resins, phenolic resins, acrylic resins, alkyd resins, polyimides, thermosetting polyesters, vinyl ester resins, silicate binders, or combinations thereof.

The coating suspension may further comprise other coating/paint components as will be apparent to those skilled in the art. Examples of such ingredients are fillers, additives (e.g., surfactants, dispersants, defoamers, catalysts, accelerators, stabilizers, coalescing agents, thixotropic agents, anti-settling agents, and dyes), coupling agents, extenders, conductive pigments, electronically conductive polymers, or combinations thereof. Also, the coating suspension is free of microspheres of glass, ceramic, or polymer, etc.

The conductive pigment may be selected from acetylene black, carbon black, expanded graphite flakes, carbon fibers, carbon nanotubes, mica coated with antimony doped tin oxide or indium tin oxide, or mixtures thereof.

The electronically conductive polymer is preferably selected from the group consisting of: polydiacetylene, polyacetylene (PAc), polypyrrole (PPy), polyaniline (PAni), polythiophene (PTh), polyisothianthrene (PITN), polyheteroarylenevinylene (PArV) in which the heteroarylene group may be thiophene, furan or pyrrole, polyparaphenylene (PpP), polyththalocyanine (PPhc), and the like, and derivatives thereof, and combinations thereof.

In some embodiments, the chemical functional groups attached to the functionalized graphene sheets are selected from the following functional groups: alkyl or aryl silanes, alkyl or aralkyl groups, hydroxy, carboxyl, amino, sulfonic acid groups (- -SO) ₃ H) An aldehyde group (aldehydic group), a quinone group (quinoid), a fluorocarbon, or a combination thereof.

Alternatively, the functional group attached to the graphene sheet contains a derivative of an azide compound selected from the group consisting of: 2-azidoethanol, 3-azidopropan-1-amine, 4- (2-azidoethoxy) -4-oxobutanoic acid, 2-azidoethyl-2-bromo-2-methylpropionate, chloroformate (chlorocarbonate), azidoformate (azidocarbonate), dichlorocarbene, carbene, aryne, nitrene, (R-) -oxycarbonylnitrene where r=any of the following groups,

And combinations thereof.

In certain embodiments, the functional group is selected from the group consisting of: hydroxyl, peroxide, ether, ketone, and aldehyde. In certain embodiments, the functionalizing agent comprises a functional group selected from the group consisting of: SO (SO) ₃ H、COOH、NH ₂ 、OHR 'CHOH, CHO, CN, COCl, halo (halide), COSH, SH, COOR', SR ', siR' ₃ 、Si(--OR’--) _y R’ ₃ -y、Si(--O--SiR’ ₂ -)OR’、R”、Li、AlR’ ₂ 、Hg--X、TlZ ₂ And Mg- -X; wherein y is an integer equal to or less than 3, R' is hydrogen, alkyl, aryl, cycloalkyl or aralkyl, cycloaryl or poly (alkyl ether), R "is fluoroalkyl, fluoroaryl, fluoroacycloalkyl, fluoroarylalkyl or cycloaryl, X is halo, and Z is carboxylate or trifluoroacetate, and combinations thereof.

The functional group may be selected from the group consisting of: amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), polyethylenepolyamines, polyamine epoxy adducts, phenolic hardeners, non-brominated curing agents, non-amine curing agents, and combinations thereof.

In some embodiments, the functional group is selected from OY, NHY, o=c-OY, p=c-NR 'Y, O =c-SY, o=c-Y, -CR' 1-OY, N 'Y, or C' Y, and Y is a functional group of a protein, peptide, amino acid, enzyme, antibody, nucleotide, oligonucleotide, antigen, or transition-state analog of an enzyme substrate, enzyme inhibitor, or enzyme substrate or is selected from R '— OH, R' — NR '' ₂ 、R'SH、R'CHO、R'CN、R'X、R'N ⁺ (R') ₃ X ^- 、R'SiR' ₃ 、R'Si(--OR'--) _y R' _3-y 、R'Si(--O--SiR' ₂ --)OR'、R'--R"、R'--N--CO、(C ₂ H ₄ O--) _w H、(--C ₃ H ₆ O--) _w H、(--C ₂ H ₄ O) _w --R'、(C ₃ H ₆ O) _w -R', and w is an integer greater than 1 and less than 200.

The present disclosure also provides an object or structure at least partially coated with a coating comprising a plurality of graphene sheets, particles of a corrosion-inhibiting pigment or a sacrificial metal, and an aqueous binder resin that binds the graphene sheets and particles of the corrosion-inhibiting pigment or the sacrificial metal together and to a surface of the object or structure, wherein the plurality of graphene sheets comprises a single layer or a few layer of graphene sheets selected from the group consisting of: a pristine graphene material having substantially zero% non-carbon elements or a non-pristine graphene material having from 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein the coating is free of silicate binders or microspheres dispersed therein.

The corrosion inhibiting pigment or sacrificial metal in the coating may be selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof. The coating applied to the object or structure typically has a thickness of from 1nm to 10mm, typically from 10nm to 1 mm. In certain embodiments, the object or structure is metallic.

The coating applied to the object or structure may contain an aqueous binder resin selected from the group consisting of: ester resins, neopentyl glycol (NPG), ethylene Glycol (EG), isophthalic acid, terephthalic acid, urethane resins, urethane ester resins, urethane-urea resins, acrylic urethane resins, or combinations thereof.

The aqueous binder resin may contain a curing agent and/or coupling agent in an amount of 1 to 30 parts by weight based on 100 parts by weight of the binder resin.

For coatings applied to objects or structures, the aqueous binder resin may contain a thermally curable resin containing a multifunctional epoxy monomer selected from the group consisting of: diglycidyl ether, dipentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, or a combination thereof.

In certain embodiments, the aqueous binder resin comprises a thermally curable resin comprising a difunctional or trifunctional epoxy monomer selected from the group consisting of: trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, tetraphenylolethane tetraglycidyl ether, p-aminophenol triglycidyl ether, 1,2, 6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycidyl triglycidyl ether, glycerol ethoxytriglycidyl ether, castor oil triglycidyl ether, propoxylated glycerol triglycidyl ether, ethylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated bisphenol a diglycidyl ether, 3, 4-epoxycyclohexylcarboxylic acid (3, 4-epoxycyclohexane) methyl ester, derivatives thereof, and mixtures thereof.

In certain embodiments, the aqueous binder resin comprises a UV radiation curable resin or lacquer selected from acrylate and methacrylate oligomers, (meth) acrylate (acrylate and methacrylate), polyols and derivatives thereof having (meth) acrylate functionality, including ethoxylated trimethylol propane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate or neopentyl glycol di (meth) acrylate, and mixtures thereof, as well as acrylate and methacrylate oligomers derived from: low molecular weight polyester resins, polyether resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, epoxy acrylates, polybutadiene resins, and polythiol-polyene resins.

In certain embodiments, the object or structure is a metal reinforcement material or member. The object or structure may be a concrete structure, a bridge.

The present disclosure also provides a method of inhibiting corrosion of a structure or object having a surface, the method comprising (i) coating at least a portion of the surface with a coating suspension comprising a plurality of graphene sheets dispersed or dissolved in a liquid medium and a resin binder, the graphene sheets being coated with a thin film of a corrosion-inhibiting pigment or sacrificial metal having a thickness of from 0.5nm to 1 μm; and (ii) at least partially removing the liquid medium from the coating suspension after the coating step is completed to form a protective coating on the surface.

Preferably, the protective coating contains corrosion-inhibiting pigments or sacrificial metal-coated graphene sheets aligned substantially parallel to each other and to the surface of the structure or object to be protected. Such orientation of the coated graphene sheets may be by using ultrasonic spraying, air-assisted spraying, or any of a variety of coating or casting procedures (e.g., comma coating, slot coating, reverse roll coating, etc.) including applying shear stress to the coating suspension upon contact with the surface to be protected.

In the method, the corrosion-inhibiting pigment or sacrificial metal is selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof. In this method, the aqueous binder resin preferably contains an aqueous thermosetting resin selected from the group consisting of: a water-soluble or dispersible epoxy resin, a water-soluble or dispersible polyurethane resin, a water-soluble or dispersible phenolic resin, a water-soluble or dispersible acrylic resin, a water-soluble or dispersible alkyd resin, or a combination thereof. The non-pristine graphene material preferably has from 1% to 30% by weight of non-carbon elements selected from O, H, N, F, cl, br, I, B, P or combinations thereof. The method may further comprise a carrier, filler, dispersant, surfactant, defoamer, catalyst, accelerator, stabilizer, coalescing agent, thixotropic agent, anti-settling agent, color dye, coupling agent, extender, conductive pigment, electronically conductive polymer, or a combination thereof.

The present disclosure also provides a method for producing a graphene-based coating suspension containing discrete graphene sheets coated with a preservative material dispersed in a liquid medium (e.g., an organic solvent). The method comprises the following steps: (a) providing a continuous film of graphene sheets into a deposition zone; (b) Introducing vapor or atoms of a precursor anticorrosive pigment or metal into a deposition zone and depositing the vapor or atoms onto the surface of the graphene sheet to form a coated film (coated film) of anticorrosive material coated graphene sheet; (c) Mechanically crushing the coating film into a plurality of graphene sheets coated with the anti-corrosion material; and (d) dispersing the plurality of corrosion-resistant material coated graphene sheets and the binder resin in a liquid medium to form a coating suspension.

In this method, a continuous film of graphene material may be produced by spraying a graphene suspension onto a solid substrate and by removing the liquid medium, wherein the graphene suspension contains sheets of graphene material dispersed in the liquid medium. In some embodiments, this continuous film of graphene sheets is produced by chemical vapor deposition of graphene material onto a solid substrate.

Preferably, the coating film has a coating thickness of the corrosion-inhibiting active material of less than 100 nm.

In certain embodiments, step (b) of forming a coating film of the corrosion-resistant material coated graphene sheets entails depositing a corrosion-resistant pigment or metal chemical vapor deposition, physical vapor deposition, sputtering, or laser-assisted thin film onto the film of the graphene sheets.

Step (c) of mechanical disruption may require air jet milling, impact milling, grinding, mechanical shearing, sonication, or a combination thereof.

In some embodiments, step (a) of providing a continuous film of graphene material comprises feeding the continuous film from a feeder roll into a deposition zone, and step (b) further comprises collecting the coated film onto a take-up roll.

Drawings

Fig. 1 shows a flow chart of the most common method for producing graphene oxide sheets, which requires chemical oxidation/intercalation, rinsing and high temperature puffing procedures.

Fig. 2 is a method for producing a graphene sheet coated with a preservative material.

Fig. 3 polarization current density and voltage (electrochemical potential) for four corrosion protection coating compositions.

Detailed Description

The present disclosure provides a graphene-based coating suspension for protecting metal surfaces from corrosion or oxidation. The coating suspension may be applied to the metal substrate surface as a primer, an intermediate coating, or a top coating (top coat).

In certain embodiments, the coating suspension comprises a plurality of graphene sheets (coated with a thin coating of a corrosion-inhibiting pigment or a sacrificial metal) dissolved or dispersed in a liquid medium (e.g., an organic solvent or water), and a binder resin. Each of these graphene sheets has two opposing parallel surfaces (or "primary surfaces"). In certain embodiments, at least 50% of one of the two primary surfaces is covered by a thin coating of corrosion-inhibiting pigment or sacrificial metal. The thin coating of the corrosion protection material preferably has a thickness of from 0.5nm to 1 μm, more preferably from 1nm to 500nm, and most preferably from 5nm to 100 nm. The graphene sheets coated with the corrosion-resistant material are discrete individual sheets having a typical length or width from 10nm to 10 μm. The graphene sheets themselves (prior to being coated with the anti-corrosive pigment or metal) typically have a thickness from 0.34nm to about 3.4 nm.

The plurality of graphene sheets contains single-layer or few-layer graphene sheets selected from the group consisting of: a pristine graphene material having substantially zero% non-carbon elements or a non-pristine graphene material having from 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof. The non-pristine graphene material may have from 1% to 30% by weight of non-carbon elements selected from O, H, N, F, cl, br, I, B, P or combinations thereof. Preferably, the coating suspension is free of microspheres (such as glass, ceramic and polymeric microspheres) as filler. In certain embodiments, the coating suspension is free of silicate binders.

In a preferred or typical coating composition (after removal of the liquid medium), the resulting solid contains from 0.1% to 30% by weight of graphene sheets, from 1% to 70% by weight (preferably from 5% to 60% and further preferably from 10% to 40%) of a corrosion-inhibiting pigment or sacrificial metal coated on the surface of the graphene sheets, and from 1% to 10% by weight of a binder resin. Of course, the sum of these three species, regardless of formulation, must be 100%.

The present disclosure also provides a method for producing a graphene-based coating suspension containing discrete graphene sheets coated with a preservative material dispersed in a liquid medium (e.g., an organic solvent). The method comprises the following steps: (a) providing a continuous film of graphene sheets into a deposition zone; (b) Introducing vapor or atoms of a precursor anticorrosive pigment or metal into a deposition zone and depositing the vapor or atoms onto the surface of the graphene sheet to form a coated film (coated film) of anticorrosive material coated graphene sheet; (c) Mechanically crushing the coating film into a plurality of graphene sheets coated with the anti-corrosion material; and (d) dispersing the plurality of corrosion-resistant material coated graphene sheets and the binder resin in a liquid medium to form a coating suspension. Preferably, the coating film has a coating thickness of the corrosion-inhibiting active material of less than 100 nm.

In this method, a continuous film of graphene sheets may be produced by spraying a graphene suspension onto a solid substrate and by removing the liquid medium, wherein the graphene suspension contains sheets of graphene material dispersed in the liquid medium. The liquid medium may be the same as or different from the liquid medium of the final coating suspension. In some embodiments, this continuous film of graphene sheets is produced by chemical vapor deposition of graphene material onto a solid substrate. In some embodiments, step (a) of providing a continuous film of graphene material comprises feeding the continuous film from a feeder roll into a deposition zone, and step (b) further comprises collecting the coated film onto a take-up roll.

In certain embodiments, step (b) of forming a coating film of the corrosion-resistant material coated graphene sheets entails depositing a corrosion-resistant pigment or metal chemical vapor deposition, physical vapor deposition, sputtering, or laser-assisted thin film onto the film of the graphene sheets. Step (c) of mechanical disruption may require air jet milling, impact milling, grinding, mechanical shearing, sonication, or a combination thereof.

Conventional corrosion protection coatings for protecting steel structures typically contain a zinc primer, wherein zinc is used as a conductive pigment to produce an anodic active coating. The steel or iron substrate to be protected acts as a cathode. Zinc acts as a sacrificial anode material protecting the steel or iron matrix. Corrosion resistance may depend on galvanic transfer of the zinc primer. The steel matrix maintains galvanic protection as long as the electron conduction pathway in the system is maintained and sufficient zinc is present to act as an anode. Unfortunately, zinc primers are typically formulated to contain high loadings of zinc particles (e.g., up to 80% zinc by weight). High zinc loadings mean great difficulty in dispersing solids in liquid media, difficulty in applying primers to the steel surface to be protected, too thick and dense a coating, and high cost. Other coating systems for protecting other types of metal structures also have serious drawbacks.

In the present disclosure, we have unexpectedly observed that by adding 1% by weight of the selectively functionalized graphene to the zinc primer, the Zn amount can be reduced from 80% to 20% by weight (4-fold reduction in Zn amount) without compromising the corrosion protection capability. This is a great improvement in performance and is completely unexpected. This 1% by weight graphene can completely replace 60% by weight zinc, which is surprising and unprecedented.

We have further observed that other elements or compounds, such as aluminum, chromium, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof, in addition to (or as alternatives to) zinc, can also be used as a corrosion-inhibiting pigment or sacrificial metal to pair with graphene sheets. Small amounts of graphene (typically from 0.1% to 10% by weight) can be used instead of up to 70% by weight of these anti-corrosive pigment materials.

The aqueous binder resin may preferably contain an aqueous thermosetting resin selected from the group consisting of: a water-soluble or dispersible epoxy resin, a water-soluble or dispersible polyurethane resin, a water-soluble or dispersible phenolic resin, a water-soluble or dispersible acrylic resin, a water-soluble or dispersible alkyd resin, or a combination thereof.

The coating suspension may further comprise other coating/paint components as will be apparent to those skilled in the art. Examples of such ingredients are fillers, additives (e.g., surfactants, dispersants, defoamers, catalysts, accelerators, stabilizers, coalescing agents, thixotropic agents, anti-settling agents, and dyes), coupling agents, extenders, conductive pigments, electronically conductive polymers, or combinations thereof. Also, the coating suspension does not contain microspheres of glass, ceramic, or polymer, etc., as fillers or additives.

The electronically conductive polymer is preferably selected from the group consisting of: polydiacetylene, polyacetylene (PAc), polypyrrole (PPy), polyaniline (PAni), polythiophene (PTh), polyisothiaindene (PITN), polyheterovinylenevinylene (PArV) in which the heteroarylene group may be thiophene, furan or pyrrole, polyparaphenylene (PpP), polyththalocyanine (PPhc), and the like, and derivatives thereof, and combinations thereof.

The coating suspension can be easily prepared by dispersing/mixing graphene sheets (coated with anti-corrosive pigments or sacrificial metals) and a binder resin in a liquid medium using well-known methods and apparatus; for example using a disperser/mixer/homogenizer or an ultrasonic generator.

The coating suspension may be applied to the substrate surface using one of many well known coating/painting methods, such as air-assisted spraying, ultrasonic spraying, painting, printing, and dip coating. In certain embodiments, the metal component may simply be immersed or immersed in a graphene-based coating suspension, and then the component removed from the graphene dispersion such that the coated graphene sheets and binder are deposited onto the surface of the metal component, with the graphene sheets bonded to the metal surface to form a layer of bonded graphene sheets. Alternatively, the coating suspension may simply be sprayed onto the surface of the metal part, the liquid medium component evaporated and the binder resin cured or set.

The binder resin may be formed of an adhesive composition containing an adhesive resin as a main component. The binder resin composition may contain a curing agent and a coupling agent together with the binder resin. Examples of the binder resin may include ester resins, urethane ester resins, acrylic resins, and acrylic urethane resins, and specifically ester resins including neopentyl glycol (NPG), ethylene Glycol (EG), isophthalic acid, and terephthalic acid. The curing agent may be present in an amount of 1 to 30 parts by weight based on 100 parts by weight of the binder resin. The coupling agent may include an epoxy silane compound.

The curing of the binder resin may be performed by heat, UV or ionizing radiation. This may involve heating the heat-curable composition to a temperature of at least 70 ℃, preferably 90 ℃ to 150 ℃ for at least 1 minute (typically up to 2 hours, and more typically from 2 minutes to 30 minutes) in order to form the hard coating.

The metal part surface may be contacted with the graphene dispersion using dipping, coating (e.g., doctor blade coating, bar coating, slot coating, comma coating, reverse roll coating, etc.), roll-to-roll processes, inkjet printing, screen printing, microcontact printing, gravure coating, spray coating, ultrasonic spray coating, electrostatic spray coating, and flexographic printing. The thickness of the hard coat layer is generally about 1nm to 1mm, preferably 10nm to 100 μm, and most preferably 100nm to 10 μm.

For the thermally curable resin, the multifunctional epoxy monomer may preferably be selected from the group consisting of diglycidyl ether, dipentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether (e.g., pentaerythritol tetraglycidyl ether), or a combination thereof. The difunctional or trifunctional epoxy monomer may be selected from the group consisting of: trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, tetraphenylolethane tetraglycidyl ether, p-aminophenol triglycidyl ether, 1,2, 6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycidyl triglycidyl ether, glycerol ethoxytriglycidyl ether, castor oil triglycidyl ether, propoxylated glycerol triglycidyl ether, ethylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated bisphenol a diglycidyl ether, 3, 4-epoxycyclohexylcarboxylic acid (3, 4-epoxycyclohexane) methyl ester, derivatives thereof, and mixtures thereof.

In certain embodiments, the thermally curable compositions of the present disclosure advantageously further contain a small amount (preferably from 0.05% to 0.20% by weight) of at least one surface active compound. It is important that the surfactant wets the substrate well resulting in a satisfactory final hard coating.

UV radiation curable resins and lacquers useful in the present disclosure are those derived from photopolymerizable monomers and oligomers, such as acrylates and methacrylate oligomers of polyfunctional compounds (the term "(meth) acrylate" refers herein to acrylates and methacrylates), such as polyols and derivatives thereof having (meth) acrylate functionality, such as ethoxylated trimethylol propane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate or neopentyl glycol di (meth) acrylate, and mixtures thereof, as well as acrylates and methacrylate oligomers derived from: low molecular weight polyester resins, polyether resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, epoxy acrylates, polybutadiene resins, polythiol-polyene resins, derivatives thereof, and combinations thereof.

UV polymerizable monomers and oligomers are coated (e.g., after withdrawal from dipping) and dried, and then exposed to UV radiation to form an optically clear crosslinked abrasion resistant layer. Preferred UV curing dosages are between 50 and 1000mJ/cm ² Between them.

UV curable resins are also typically ionizing radiation curable. The ionizing radiation curable resin may contain relatively large amounts of reactive diluents. Reactive diluents useful herein include monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, vinyl toluene, and N-vinyl pyrrolidone, and polyfunctional monomers such as trimethylol propane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, or neopentyl glycol di (meth) acrylate.

The binder resins described above are typically solvent-based and are initially soluble in organic solvents (prior to curing or crosslinking). However, most of the monomers or polymers in these binder resins (prior to curing) may be chemically modified (e.g., carboxylated, hydroxylated, or functionalized in some way) to make them soluble or dispersible in water. They then become a component of the aqueous coating system. There are commercially available resin systems that are water-soluble or water-dispersible in nature.

The preparation of graphene sheets and graphene dispersions is as follows: carbon is known to have five unique crystal structures including diamond, fullerenes (0-D nanographitic material), carbon nanotubes or carbon nanofibers (1-D nanographitic material), graphene (2-D nanographitic material) and graphite (3-D graphitic material). Carbon Nanotubes (CNTs) refer to tubular structures grown with single or multiple walls. Carbon Nanotubes (CNT) and Carbon Nanofibers (CNF) have diameters on the order of a few nanometers to a few hundred nanometers. Its longitudinal, hollow structure imparts unique mechanical, electrical and chemical properties to the material. CNT or CNF is a one-dimensional nanocarbon or 1-D nanographite material.

As early as 2002, our research group has initiated the development of graphene materials and related production methods: (1) U.S. Pat. No. 7,071,258 (07/04/2006), application filed on 21/10/2002, and "Nano-scaled Graphene Plates [ Nano-scaled graphene plates ]"; (2) Jang et al, "Process for Producing Nano-scaled Graphene Plates [ method for producing nanoscale graphene plates ]", U.S. patent application Ser. No. 10/858,814 (06/03/2004) (U.S. patent publication No. 2005/0271574); and (3) B.Z.Jang, A.Zhamu and J.Guo, "Process for Producing Nano-scaled Platelets and Nanocomposites [ methods for producing nanoscaled platelets and nanocomposites ]", U.S. patent application Ser. No. 11/509,424 (08/25/2006) (U.S. patent publication No. 2008-0048152).

The single-layer graphene sheet is composed of carbon atoms occupying a two-dimensional hexagonal lattice. Multilayer graphene is a platelet made up of more than one graphene plane. Individual monolayer graphene sheets and multilayer graphene sheets are collectively referred to herein as nanographene platelets (NGPs) or graphene materials. NGPs include pristine graphene (essentially 99% carbon atoms), micro-oxidized graphene (< 5% oxygen by weight), oxidized graphene (≡5% oxygen by weight), micro-fluorinated graphene (< 5% fluorine by weight), fluorinated graphene (≡5% fluorine by weight), other halogenated graphene, and chemically functionalized graphene.

NGPs have been found to have an unusual set of physical, chemical and mechanical properties. For example, graphene was found to exhibit the highest intrinsic strength and highest thermal conductivity of all existing materials. While the practical electronic device application of graphene (e.g., replacing Si as the backbone in a transistor) is not envisioned to occur within 5-10 years in the future, its use as a nanofiller in composites and as an electrode material in energy storage devices is upcoming. The availability of a large number of processable graphene sheets is critical to the successful development of graphene composites, energy and other applications.

Recently, we reviewed the methods of producing NGP and NGP nanocomposites [ Bor z. Jang and a Zhamu, "Processing of Nano Graphene Platelets (NGPs) and NGP Nanocomposites: a Review [ nanographene platelet (NGP) and processing of NGP nanocomposites: general ] ", J.materials Sci. [ journal of Material science ]43 (2008) 5092-5101].

Very useful processes (fig. 1) require the treatment of natural graphite powder with intercalation and oxidation agents (e.g. concentrated sulfuric and nitric acids, respectively) to obtain Graphite Intercalation Compounds (GIC) or indeed Graphite Oxides (GO). [ William S.hummers, jr. Et al, preparation of Graphitic Oxide [ preparation of graphite oxide ]]Journal of the American Chemical Society [ American chemical society ]]1958, 1339]. The inter-graphene-plane spacing of the graphite prior to intercalation or oxidation is about 0.335nm (L _d ＝1/2d ₀₀₂ =0.335 nm). The inter-planar graphene spacing is increased to a value typically greater than 0.6nm by intercalation and oxidation treatments. This is the first expansion stage that the graphite material undergoes during this chemical route. The resulting GIC or GO is then subjected to further expansion (often referred to as puffing) using a thermal shock exposure method or a solution-based ultrasound-assisted graphene layer puffing (expansion) method.

In the thermal shock exposure process, the GIC or GO is exposed to high temperatures (typically 800 ℃ -1,050 ℃) for a short period of time (typically 15 to 60 seconds) to expand or expand the GIC or GO to form expanded or further expanded graphite, typically in the form of "graphite worms" composed of graphite platelets that remain interconnected with each other. Such a thermal shock procedure may produce some separate graphite flakes or graphene sheets, but typically a majority of the graphite flakes remain interconnected. Typically, the expanded graphite or graphite worms are then subjected to a flake separation treatment using air milling, mechanical shearing, or sonication in water. Thus, method 1 basically requires three different procedures: first expansion (oxidation or intercalation), further expansion (or "puffing") and separation.

In a solution-based separation process, the expanded or puffed GO powder is dispersed in water or an aqueous alcohol solution and subjected to sonication. It is important to note that in these methods, sonication is used after intercalation and oxidation of the graphite (i.e. after a first expansion) and typically after thermal shock exposure of the resulting GIC or GO (after a second expansion). Alternatively, GO powder dispersed in water is subjected to ion exchange or lengthy purification procedure in such a way that repulsive force between ions existing in the interplanar space outweighs van der waals force between graphene, resulting in separation of graphene layers.

In the above examples, the starting material for preparing graphene sheets or NGPs is a graphite material that may be selected from the group consisting of: natural graphite, artificial graphite, graphite oxide, graphite fluoride, graphite fibers, carbon nanofibers, carbon nanotubes, mesophase Carbon Microbeads (MCMB) or Carbonaceous Microbeads (CMS), soft carbon, hard carbon, and combinations thereof.

Graphite oxide may be prepared by dispersing or immersing a lamellar graphite material (e.g., a powder of natural lamellar graphite or synthetic graphite) in an oxidizing agent, typically a mixture of an intercalation agent (e.g., concentrated sulfuric acid) and an oxidizing agent (e.g., nitric acid, hydrogen peroxide, sodium perchlorate, potassium permanganate) at a desired temperature (typically 0 deg.c-70 deg.c) for a sufficient period of time (typically 4 hours to 5 days). The resulting graphite oxide particles are then rinsed several times with water to adjust the pH to typically 2-5. The resulting suspension of graphite oxide particles dispersed in water is then subjected to ultrasonic treatment to produce a dispersion of individual graphene oxide sheets dispersed in water. Small amounts of reducing agents (e.g., na ₄ B) To obtain reduced graphene oxide (RDO) sheets.

In order to shorten the time required for the generation of the precursor solution or suspension, graphite oxide may be selected to a certain extent in a shorter time (for example, 30 minutes to 4 hours) to obtain a Graphite Intercalation Compound (GIC). The GIC particles are then exposed to a thermal shock, preferably in the temperature range 600 ℃ to 1100 ℃ for a typical 15 to 60 seconds, to obtain expanded graphite or graphite worms, optionally (but preferably) subjecting the graphite or graphite worms to mechanical shearing (e.g. using a mechanical shearing machine or an ultrasonic generator) to crush the graphite flakes constituting the graphite worms. The separated graphene sheets (after mechanical shearing) or the uncrushed graphite worms or individual graphite flakes are then redispersed in water, acid or organic solvent and sonicated to obtain graphene dispersions.

The pristine graphene material is preferably produced by one of three methods: (A) Intercalation of the graphite material with a non-oxidizing agent, followed by thermal or chemical expansion in a non-oxidizing environment; (B) Subjecting the graphite material to a supercritical fluid environment to effect interlaminar penetration and expansion of the graphene; or (C) dispersing the graphite material in powder form into an aqueous solution containing a surfactant or dispersant to obtain a suspension, and subjecting the suspension to direct ultrasonic treatment to obtain a graphene dispersion.

In procedure (a), a particularly preferred step comprises (i) intercalation of the graphite material with a non-oxidising agent selected from: an alkali metal (e.g., potassium, sodium, lithium, or cesium), an alkaline earth metal, or an alloy, mixture, or eutectic of an alkali metal or alkaline earth metal; and (ii) a chemical puffing treatment (e.g., by immersing the potassium intercalated graphite in an ethanol solution).

In procedure (B), the preferred step comprises immersing the graphite material in a supercritical fluid such as carbon dioxide (e.g., at a temperature T >31 ℃ and a pressure P >7.4 MPa) and water (e.g., at a temperature T >374 ℃ and a pressure P >22.1 MPa) for a period of time sufficient to effect interpenetration (temporary intercalation) of the graphene. This step is followed by a sudden depressurization to expand the individual graphene layers. Other suitable supercritical fluids include methane, ethane, ethylene, hydrogen peroxide, ozone, water oxidation (water containing high concentrations of dissolved oxygen), or mixtures thereof.

In procedure (C), the preferred steps include (a) dispersing particles of graphite material in a liquid medium having a surfactant or dispersant therein to obtain a suspension or slurry; and (b) exposing the suspension or slurry to ultrasound at an energy level (a process commonly referred to as sonication) for a time sufficient to produce a graphene dispersion of separated graphene sheets (non-oxidized NGP) dispersed in a liquid medium (e.g., water, alcohol, or an organic solvent).

NGPs having an oxygen content of not more than 25% by weight, preferably less than 20% by weight, further preferably less than 5% by weight, may be produced. Typically, the oxygen content is between 5% and 20% by weight. The oxygen content may be determined using chemical elemental analysis and/or X-ray photoelectron spectroscopy (XPS).

The lamellar graphite material used in the prior art processes for the production of GIC, graphite oxide and subsequently manufactured expanded graphite, flexible graphite sheets and graphene platelets is in most cases natural graphite. However, the present disclosure is not limited to natural graphite. The starting material may be selected from the group consisting of: natural graphite, synthetic graphite (e.g., highly oriented pyrolytic graphite HOPG), graphite oxide, graphite fluoride, graphite fibers, carbon nanofibers, carbon nanotubes, mesophase Carbon Microspheres (MCMB) or Carbonaceous Microspheres (CMS), soft carbon, hard carbon, and combinations thereof. All of these materials contain graphitic crystallites consisting of layers of graphene planes stacked or bonded together by van der waals forces. In natural graphite, multiple stacks of graphene planes are clustered together, with the orientation of the graphene planes being different from stack to stack. In carbon fibers, the graphene planes are generally oriented in a preferred direction. Generally, soft carbon is a carbonaceous material obtained by carbonization of liquid aromatic molecules. Their aromatic rings or graphene structures are more or less parallel to each other so that further graphitization is possible. Hard carbon is a carbonaceous material obtained from aromatic solid materials (e.g., polymers such as phenolic resins and polyfurfuryl alcohol). Their graphene structures are relatively randomly oriented and, therefore, even at temperatures above 2500 ℃, further graphitization is difficult to achieve. However, graphene sheets do exist in these carbons.

Fluorinated graphene or graphene fluoride is used herein as an example of a halogenated graphene material group. There are two different methods that have been followed to produce fluorinated graphene: (1) fluorination of pre-synthesized graphene: the process requires the use of a fluorinating agent such as XeF ₂ Or F-based plasma treatment of graphene prepared by mechanical puffing or by CVD growth; (2) puffing of the multilayer graphite fluoride: both mechanical expansion and liquid phase expansion of graphite fluoride can be readily achieved [ f.karlicky et al, "Halogenated Graphenes: rapidly Growing Family of Graphene Derivatives [ halogenated graphene: fast-growing family of graphene derivatives]"ACS Nano [ ACS Nano ]]2013,7 (8), pages 6434-6464]。

F ₂ Interaction with graphite at high temperature results in covalent graphite fluoride (CF) _n Or (C) ₂ F) _n Forming Graphite Intercalation Compound (GIC) C at low temperature _x F (x is more than or equal to 2 and less than or equal to 24). At (CF) _n The medium carbon atoms being sp3 hybridized and the fluorocarbon layer thus being corrugatedAnd a cyclohexane chair connected in a reverse way. At (C) ₂ F) _n Only half of the C atoms are fluorinated and each pair of adjacent carbon sheets are linked together by a covalent C-C bond. Systematic studies of the fluorination reaction show that the resulting F/C ratio depends largely on the fluorination temperature, the partial pressure of fluorine in the fluorinated gas, and the physical properties of the graphite precursor, including graphitization degree, particle size, and specific surface area. In addition to fluorine (F) ₂ ) In addition, other fluorinating agents can be used, although most of the prior art references involve the use of F ₂ The gas is fluorinated (sometimes in the presence of fluoride).

In order to expand the layered precursor material into the state of individual graphene monolayers or few layers, the attractive forces between adjacent layers must be overcome and the layers further stabilized. This can be achieved by covalent modification of the graphene surface with functional groups or by non-covalent modification with specific solvents, surfactants, polymers, or donor-acceptor aromatic molecules. The process of liquid phase puffing includes sonicating graphite fluoride in a liquid medium to produce graphene fluoride sheets dispersed in the liquid medium. The resulting dispersion can be used directly for graphene deposition on the surface of a polymer component.

Nitridation of graphene can be performed by exposing a graphene material (e.g., graphene oxide) to ammonia at high temperatures (200 ℃ -400 ℃). The graphene nitride can also be formed at a lower temperature by a hydrothermal method; for example by sealing GO and ammonia in an autoclave and then heating to 150-250 ℃. Other methods of synthesizing nitrogen doped graphene include nitrogen plasma treatment on graphene, arc discharge between graphite electrodes in the presence of ammonia, ammonolysis of graphene oxide under CVD conditions, and hydrothermal treatment of graphene oxide and urea at different temperatures.

For purposes of defining the claims of the present application, NGP or graphene materials include single and multi-layered (typically less than 10 layers, few layers graphene) discrete sheets/platelets of pristine graphene, graphene oxide, reduced Graphene Oxide (RGO), fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, doped graphene (e.g., doped with B or N). The pristine graphene has substantially 0% oxygen. RGOs typically have an oxygen content of 0.001% -5% by weight. Graphene oxide (including RGO) may have 0.001% -50% oxygen by weight. All graphene materials, except native graphene, have 0.001% -50% by weight of non-carbon elements (e.g., O, H, N, B, F, cl, br, I, etc.). These materials are referred to herein as non-pristine graphene materials. The graphene of the present application may contain native or non-native graphene and the method of the present application allows this flexibility. These graphene sheets may all be chemically functionalized.

Graphene sheets have a substantial proportion of edges corresponding to the graphite crystal edge planes. The carbon atoms in the edge planes are reactive and must contain some sort of heteroatom or group to satisfy the carbon valency. In addition, there are many types of functional groups (e.g., hydroxyl and carboxyl) that naturally occur at the edges or surfaces of graphene sheets produced by chemical or electrochemical methods. Many chemical functional groups (e.g. -NH) ₂ Etc.) can be readily imparted to the graphene edges and/or surfaces using methods well known in the art.

In a preferred embodiment, the resulting functionalized Graphene Sheets (NGPs) may broadly be of the formula (e) [ NGPs ]]--R _m Wherein m is the number of different functional group types (typically between 1 and 5), R is selected from SO ₃ H、COOH、NH ₂ OH, R 'CHOH, CHO, CN, COCl, halo, COSH, SH, COOR', SR ', siR' ₃ 、Si(--OR’--) _y R’ _3-y 、Si(--O--SiR’ ₂ -)OR’、R”、Li、AlR’ ₂ 、Hg--X、TlZ ₂ And Mg- -X; wherein y is an integer equal to or less than 3, R 'is hydrogen, alkyl, aryl, cycloalkyl or aralkyl, cycloaryl or poly (alkyl ether), R' is fluoroalkyl, fluoroaryl, fluoroacycloalkyl, fluoroarylalkyl or cycloaryl, X is halo, and Z is carboxylate or trifluoroacetate.

A commonly used curing agent for epoxy resins is Diethylenetriamine (DETA), which has three-NH groups ₂ A group. If it isDETA is contained in the impingement chamber, three-NH ₂ One of the groups may be bonded to the edge or surface of the graphene sheet, and the remaining two unreacted-NH ₂ The groups can be used for subsequent reaction with epoxy resins. This arrangement provides good interfacial bonding between the NGP (graphene sheets) and the epoxy-based binder resin.

Other useful chemical functional groups or reactive molecules may be selected from the group consisting of: amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), hexamethylenetetramine, polyethylenepolyamines, polyamine epoxy adducts, phenolic hardeners, non-brominated curatives, non-amine curatives, and combinations thereof. These functional groups are multifunctional and have the ability to react with at least two chemical species from at least two ends. Most importantly, they can be bonded to the edges or surfaces of graphene using one end thereof, and can react with epoxide or epoxy resin at one or both other ends in a subsequent epoxy curing stage.

Above-described [ NGP ]]--R _m May be further functionalized. The resulting graphene sheets include a composition having the formula: [ NGP ]]--A _m Wherein a is selected from OY, NHY, o=c-OY, p=c-NR 'Y, O =c-SY, o=c-Y, -CR' 1-OY, N 'Y or C' Y and Y is a protein, peptide, amino acid, enzyme, antibody, nucleotide, oligonucleotide, antigen, or transition state analogue of enzyme substrate, enzyme inhibitor or enzyme substrate, or is selected from R 'OH, R' NR '' ₂ 、R'SH、R'CHO、R'CN、R'X、R'N ⁺ (R') ₃ X ^- 、R'SiR' ₃ 、R'Si(--OR'--) _y R' _3-y 、R'Si(--O--SiR' ₂ --)OR'、R'--R”、R'--N--CO、(C ₂ H ₄ O--) _w H、(--C ₃ H ₆ O--) _w H、(--C ₂ H ₄ O) _w --R'、(C ₃ H ₆ O) _w -R', and w is an integer greater than 1 and less than 200. CNTs can be similarly functionalized.

The NGP and conductive additives (e.g., carbon nanofibers) may also be functionalized to produce a composition having the formula: [ NGP ]]--[R'--A] _m Wherein m, R' and A are as defined above. The compositions of the present disclosure also include NGPs on which certain cyclic compounds are adsorbed. These include compositions of matter having the formula: [ NGP ]]--[X--R _a ] _m Wherein a is a number of zero or less than 10, X is a polynuclear aromatic moiety, a polynuclear aromatic moiety or a metallo-polynuclear aromatic moiety, and R is as defined above. Preferred cyclic compounds are planar. More preferred cyclic compounds for adsorption are porphyrins and phthalocyanines. The adsorbed cyclic compound may be functionalized. Such compositions include those having the formula [ NGP ]]--[X--A _a ] _m Wherein m, a, X and a are as defined above.

The functionalized NGPs of the present disclosure can be prepared directly by sulfonation or electrophilic addition to the surface of the deoxygraphene platelets. The graphene platelets may be processed prior to contact with the functionalizing agent. Such processing may include dispersing graphene platelets in a solvent. In some examples, the platelets may then be filtered and dried prior to contacting. One particularly useful type of functional group is carboxylic acid moieties that naturally occur on the surface of the NGP if the NGP is prepared from the acid intercalation route discussed previously. If carboxylic acid functionalization is desired, the NGP can be subjected to chlorate, nitric acid, or ammonium persulfate oxidation.

Carboxylic acid functionalized graphene sheets or platelets are particularly useful because they can serve as starting points for the preparation of other types of functionalized NGPs. For example, an alcohol or amide can be readily linked to an acid to provide a stable ester or amide. If the alcohol or amine is part of a di-or poly-functional molecule, the linkage through O-or NH-leaves other functional groups as pendant groups. These reactions can be carried out using any method developed for esterification with alcohols or amination of carboxylic acids with amines as known in the art. Examples of such methods can be found in gw.anderson et al, j.amer.chem.soc. [ american society of chemistry ]86,1839 (1964), which is hereby incorporated by reference in its entirety. Amino groups can be directly introduced onto the graphite platelets by: the platelets are treated with nitric acid and sulfuric acid to obtain nitrated platelets, which are then chemically reduced with a reducing agent such as sodium dithionite to obtain amino-functionalized platelets.

In some embodiments, the chemically functionalized graphene sheets contain chemical functional groups selected from the group consisting of: alkyl or aryl silanes, alkyl or aralkyl groups, hydroxy, carboxyl, amino, sulfonic acid (- -SO) ₃ H) An aldehyde group, a quinone group, a fluorocarbon, or a combination thereof. Alternatively, the functional group contains a derivative of an azide compound selected from the group consisting of: 2-azidoethanol, 3-azidopropan-1-amine, 4- (2-azidoethoxy) -4-oxobutanoic acid, 2-azidoethyl-2-bromo-2-methylpropionate, chloroformate, azidoformate, dichlorocarbene, carbene, aryne, nitrene, (R-) -oxycarbonylnitrene where R = any of the following groups,

And combinations thereof.

In certain embodiments, the functional group is selected from the group consisting of: hydroxyl, peroxide, ether, ketone, and aldehyde. In certain embodiments, the functionalizing agent comprises a functional group selected from the group consisting of: SO (SO) ₃ H、COOH、NH ₂ OH, R 'CHOH, CHO, CN, COCl, halo (halide), COSH, SH, COOR', SR ', siR' ₃ 、Si(--OR’--) _y R’ ₃ -y、Si(--O--SiR’ ₂ -)OR’、R”、Li、AlR’ ₂ 、Hg--X、TlZ ₂ And Mg- -X; wherein y is an integer equal to or less than 3, R' is hydrogen, alkyl, aryl, cycloalkyl or aralkyl, cycloaryl or poly (alkyl ether), R "is fluoroalkyl, fluoroaryl, fluoroacycloalkyl, fluoroarylalkyl or cycloaryl, X is halo, and Z is carboxylate or trifluoroacetate, and combinations thereof.

The functional group may be selected from the group consisting of: amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), polyethylenepolyamines, polyamine epoxy adducts, phenolic hardeners, non-brominated curing agents, non-amine curing agents, derivatives thereof, and combinations thereof.

In some embodiments, the functional group may be selected from OY, NHY, o=c-OY, p=c-NR 'Y, O =c-SY, o=c-Y, -CR' 1-OY, N 'Y, or C' Y, and Y is a functional group of a protein, peptide, amino acid, enzyme, antibody, nucleotide, oligonucleotide, antigen, or transition-state analog of an enzyme substrate, enzyme inhibitor, or enzyme substrate or is selected from R '— OH, R' — NR '' ₂ 、R'SH、R'CHO、R'CN、R'X、R'N ⁺ (R') ₃ X ^- 、R'SiR' ₃ 、R'Si(--OR'--) _y R' _3-y 、R'Si(--O--SiR' ₂ --)OR'、R'--R"、R'--N--CO、(C ₂ H ₄ O--) _w H、(--C ₃ H ₆ O--) _w H、(--C ₂ H ₄ O) _w --R'、(C ₃ H ₆ O) _w -R', and w is an integer greater than 1 and less than 200.

Once chemically functionalized or nonfunctionalized graphene sheets are fabricated, a thin layer of corrosion resistant material may be coated on at least one of the two primary surfaces. The method for producing a graphene-based coating suspension comprises: (a) providing a continuous film of graphene sheets into a deposition zone; (b) Introducing vapor or atoms of a precursor anticorrosive pigment or metal into the deposition zone and depositing the vapor or atoms onto the surface of the graphene sheets to form a coating film of anticorrosive material coated graphene sheets; (c) Mechanically crushing the coating film into a plurality of graphene sheets coated with the anti-corrosion material; and (d) dispersing the plurality of corrosion-resistant material coated graphene sheets and the binder resin in a liquid medium to form a coating suspension.

In step (a), the continuous film of graphene sheets may be produced by Chemical Vapor Deposition (CVD) of graphene onto a solid substrate. CVD, however, is an expensive process. Alternatively and preferably, as shown in fig. 2, the continuous film may be produced by preparing a suspension of graphene material sheets (e.g., graphene oxide sheets) in a liquid medium (e.g., water) and spraying the suspension onto a solid substrate surface to form a graphene film. Preferably, the graphene sheets are advanced and deposited onto the substrate surface using an ultrasonic or electrostatic spray device such that the plurality of graphene sheets overlap to form a coherent film from about 0.5nm to several microns thick (preferably from 1nm to 20 nm).

The graphene film (with or without a support matrix) is then introduced into a deposition zone (e.g., a vacuum chamber or CVD chamber) where a vapor or atomic stream of the corrosion-resistant material is deposited onto one surface of the graphene film to form a coated film (e.g., a Zn-coated graphene film). The deposition may be accomplished by Physical Vapor Deposition (PVD), sputtering, laser-assisted deposition, chemical vapor deposition (including plasma-enhanced CVD and hot filament CVD), atomic layer deposition, and solution deposition. The thickness of the coating of corrosion inhibiting material is preferably less than 500nm thick, more preferably less than 100nm, even more preferably less than 50nm, and most preferably less than 20nm.

Referring again to fig. 2, the corrosion-resistant material coated graphene film is then subjected to mechanical disruption to produce a plurality of corrosion-resistant material coated graphene sheets having a transverse dimension preferably in the range from 10nm to 10 μm, but more preferably from 100nm to 3 μm.

As shown in the top part of fig. 2, using a graphene film prepared from a graphene suspension by deposition is preferred over CVD graphene films because of the need to break the film into small pieces of coated graphene sheets after coating with the corrosion-resistant material. Continuous graphene films made from overlapping graphene sheets can be easily broken along the boundaries of the original graphene sheets. The resulting coated graphene sheets are comparable in size to the original graphene material sheets. The suspension-derived graphene film is much weaker than the CVD graphene film. However, we have transformed this weakness into the advantageous features of producing coated graphene sheets of the desired size.

The resulting graphene dispersion may be further added with other ingredients (fillers, dispersants, color pigments, extenders, defoamers, catalysts, accelerators, stabilizers, coalescents, thixotropic agents, anti-settling agents, etc.) to prepare a more reactive dispersion for use in graphene coating compositions for protecting metal parts. The metal part may simply be immersed in the graphene suspension for a few seconds to a few minutes (preferably 5 seconds to 15 minutes) and then the polymer part withdrawn from the graphene-liquid dispersion. After removal of the liquid (e.g., by natural evaporation or forced evaporation), the graphene sheets are naturally coated on and bonded to the surface of the polymer component.

Characterization of these corrosion protection coating systems by using methods well known in the art; for example, salt Spray Tests (SST) and cyclic voltammetry tests (current density and voltage) according to ASTM B117 (ISO 9277) are performed to obtain cathodic and anodic polarization currents, etc.

The following examples are provided to illustrate some of the specific details regarding the best mode of practicing the disclosure and should not be construed as limiting the scope of the disclosure.

Example 1: sulfuric acid intercalated and expanded graphene oxide from p-MCMB

MCMB (medium carbon microsphere) is supplied by medium tempering work, inc (China Steel Chemical Co). The material has a weight of about 2.24g/cm ³ Wherein the median particle diameter is about 16 μm. MCMB (10 g) was intercalated with an acid solution (4:1:0.05 ratio of sulfuric acid, nitric acid and potassium permanganate) for 48 hours. After the reaction was completed, the mixture was poured into deionized water and filtered. The intercalated MCMB was repeatedly washed in a 5% solution of HCl to remove most of the sulfate ions. The sample was then repeatedly washed with deionized water until the pH of the filtrate was neutral. The slurry was dried and stored in a vacuum oven at 60 ℃ for 24 hours. A dried powder sample was placed in a quartz tube and inserted into a horizontal tube furnace preset at a desired temperature of 800 ℃ to 1,100 ℃ for 30 to 90 seconds to obtain graphene sheets. A certain amount of graphene sheets was mixed with water and sonicated at 60-W power for 10 minutes to obtain a graphene dispersion.

The graphene-water dispersion was cast on a glass substrate to form a graphene film, which was deposited with Zn and Al using physical vapor deposition and sputtering, respectively. The preservative material coated film was then cut into small pieces, which were subjected to air jet milling to produce discrete coated graphene sheets.

A small sample was taken, dried and observed with TEM to find a majority of NGP between 1 and 10 layers. The oxygen content of the resulting graphene powder (GO or RGO) is from 0.1% to about 25%, depending on the puffing temperature and time.

To several suspensions of coated graphene sheets, various other pigments and ingredients were added, respectively, to produce different corrosion-resistant coating compositions.

Example 2: oxidation and puffing of natural graphite

Graphite oxide was prepared by oxidizing graphite flakes with sulfuric acid, sodium nitrate and potassium permanganate in a ratio of 4:1:0.05 at 30 ℃ for 48 hours according to the method of Hummers [ U.S. patent No. 2,798,878, 7 month 9 in 1957 ]. After the reaction was completed, the mixture was poured into deionized water and filtered. The sample was then washed with 5% HCl solution to remove most of the sulfate ions and residual salts, and then repeatedly rinsed with deionized water until the pH of the filtrate was about 4. The intention is to remove all sulfuric acid and nitric acid residues from the graphite interstices. The slurry was dried and stored in a vacuum oven at 60 ℃ for 24 hours.

The dried intercalated (oxidized) compound was puffed as follows: the sample was placed in a quartz tube, which was inserted into a horizontal tube furnace preset at 1050 ℃ to obtain highly expanded graphite. The expanded graphite was dispersed in water together with 1% surfactant in a flat bottom flask at 45 ℃ and the resulting suspension was subjected to ultrasonic treatment for 15 minutes to obtain a dispersion of Graphene Oxide (GO) sheets.

The graphene-water dispersion was cast on a glass substrate to form a graphene film, which was used for deposition of Zn using physical vapor deposition. The Zn-coated film was then cut into small pieces, which were subjected to air jet milling to produce discrete coated graphene sheets. To several suspensions of coated graphene sheets, various other pigments and ingredients were added, respectively, to produce different corrosion-resistant coating compositions. The coating suspension is applied to the steel structure surface using ultrasonic spray or pressurized air assisted spray to help align the coated graphene sheets parallel to each other and substantially parallel to the steel structure surface.

Example 3: preparation of raw graphene sheets

The raw graphene sheets are produced by using a direct sonication or a liquid-phase puffing process. In a typical procedure, 5 grams of graphite flakes milled to a size of about 20 μm were dispersed in 1,000ml deionized water (containing 0.1% dispersant by weight, from DuPont (DuPont))FSO) to obtain a suspension. An ultrasonic energy level of 85W (Branson S450 ultrasonic generator) was used for puffing, separation and size reduction of graphene sheets for a period of 15 minutes to 2 hours. The resulting graphene sheets are pristine graphene that has never been oxidized and is oxygen-free and relatively defect-free.

Example 4: preparation of fluorinated graphene

We have used several methods to produce GF, but only one method is described herein as an example. In a typical procedure, highly Expanded Graphite (HEG) is prepared from intercalated compound ₂ F·xClF ₃ And (3) preparation. HEG is further fluorinated with chlorine trifluoride vapor to produce Fluorinated Highly Expanded Graphite (FHEG). The pre-cooled Teflon (Teflon) reactor is filled with 20-30mL of liquid pre-cooled ClF ₃ The reactor was then closed and cooled to liquid nitrogen temperature. Subsequently, no more than 1g HEG is placed in a container having a container for ClF ₃ The gas enters the pores of the reactor. After 7-10 days, a product with an approximate C is formed ₂ F an off-white product. The GF flakes were then dispersed in a halogenated solvent to form a suspension.

Example 5: preparation of graphene nitride

The Graphene Oxide (GO) synthesized in example 2 was finely ground with urea in different proportions and the granulated mixture was heated (900W) in a microwave reactor for 30s. The product was washed several times with deionized water and dried in vacuo. In this method, graphene oxide is simultaneously reduced and doped with nitrogen. The resulting graphene-urea mass ratio products were designated N-1, N-2 and N-3 with 1/0.5, 1/1 and 1/2, respectively, and the nitrogen content of these samples was 14.7wt.%, 18.2wt.%, and 17.5wt.%, respectively, as determined by elemental analysis. These graphene nitride sheets remain dispersible in water.

Example 6: functionalized graphene as preservative component

The chemical functional groups involved in this study include azide (2-azidoethanol), alkylsilane, hydroxyl, carboxyl, amine, sulfonic acid (- -SO) ₃ H) And Diethylenetriamine (DETA). These functionalized graphene sheets are supplied by taiwan graphene corporation of taibei city, taiwan, china. After removal of the water and curing at 150 ℃ for 15 minutes, the graphene sheets bond well to the metal surface.

We have observed that in general, the metal part surface can be well bonded to the functionalized graphene sheets of the present invention with an aqueous binder resin. The coated surface is typically smoother than if the functionalized graphene sheets are included as a corrosion-inhibiting pigment with an anodic metal such as Zn or Al, as compared to the metallic pigment alone.

Example 7: polyurethane-based aqueous binder resins

Several hydroxyl/carboxyl functional polyurethane dispersions were prepared by a non-isocyanate process according to scheme 1 shown below:

first, a polymer is synthesized by reacting a diester with a polyol in the presence of an organometallic catalyst at 200℃to 220℃under vacuum. Methanol is a by-product of the transesterification reaction. Subsequently, hydroxy-functionalized urethane diol was added and propylene glycol was removed in vacuo at 180 ℃. Hydroxy-functional urethane diols are prepared by a non-isocyanate process using the reaction between a cyclic carbonate and a diamine. The resin is then carboxyl-functionalized and dispersed in water by means of a neutralizing tertiary amine. The polyurethane dispersion has a number average molecular weight in the range of about 3000 to 4000 g/mol.

Solvent-based polyurethane resins are widely available from commercial sources.

Example 8: aqueous binder resins based on polyurethane-urea copolymers

Two polyurethane-urea dispersions were prepared by the prepolymer isocyanate process given in scheme 2. This process actually produces a polyurethane-urea polymer. The chain extension reaction of the isocyanate-terminated polyurethane with the diamine forms the urea moiety.

The melamine resin used as the crosslinking agent is a commercially available version of hexamethylol melamine hexamethylol ether (hexakis (methoxymethyl) melamine, HMMM) having a degree of polymerization of about 1.5, an average molecular weight of 554, and an average theoretical functionality of 8.3. The aqueous acrylic dispersion used for formulation was Acrysol WS-68 from Rohm and Haas, a hydroxy/carboxy functionalized resin. Water-dispersible polyisocyanate (Bayhydur XP-7007, a modified aliphatic isocyanate trimer) from Bayer company (Bayer Corporation) was used for crosslinking.

Example 9: water-soluble alkyd resins

In a typical procedure, a vessel equipped with a stirrer, temperature controller and decanter is charged with the following raw materials and the charge is heated under stirring: soybean fatty acid (33% by weight), trimethylolpropane (33%), trimellitic anhydride (8.5%), isophthalic acid 24%, dibutyltin oxide (0.5%) and xylene (1%). Water is formed as the reaction proceeds and azeotropically removed with xylene. Heating was continued until an acid number of 39 and a hydroxyl number of 140 were obtained. The reaction was then stopped. The reaction mixture was diluted with butyl cellulose to a non-volatile content of 70% by weight to give an alkyd varnish. The resin varnish was neutralized with triethylamine and adjusted to a non-volatile content of 40% by weight with deionized water to give a water-soluble alkyd resin varnish. The varnish had an effective acid number of 33.

Example 10: epoxy resin

The aqueous epoxy resins used in this study were based on "type 1" (epoxy equivalent weight of about 500-600) solid epoxy dispersions and hydrophobic amine adduct curing agents. Both components utilize nonionic surfactants that are pre-reacted into the epoxy resin and amine components. One example of such an aqueous epoxy resin is EPI-REZ 6520 (hansen specialty chemicals (Hexion Specialty Chemicals co.)) and EPIKURE 6870 (modified polyamine adduct). Solvent-based epoxy resins are widely available from commercial sources.

Fig. 2 summarizes some representative test results, showing that adding 1% by weight of selectively functionalized graphene sheets (single layer graphene) to the zinc primer allows the required amount of Zn to be reduced from 80% to 20% by weight (4-fold reduction in Zn amount) without compromising corrosion resistance. It was surprising and unprecedented that 1% by weight of single layer graphene could completely replace 60% by weight of zinc. The sum of Zn particles and graphene sheets was about 21% by weight in the sample. In contrast, only 15% by weight (14% Zn coated on 1% graphene sheets) was sufficient to achieve the same level of corrosion protection.

Furthermore, 10% by weight of the few-layer graphene can effectively replace 70% by weight of the Zn particles. The sum of Zn particles and few-layer graphene sheets is about 20% by weight in the sample. If Zn is coated on the graphene surface, a total of 17% is sufficient (10% Zn is coated on 7% graphene sheets). These dramatic improvements in performance are indeed unexpected.

We have further observed that other elements or compounds, such as aluminum, chromium, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof, in addition to (or as alternatives to) zinc, can also be used as a corrosion-inhibiting pigment or sacrificial metal to pair with different types of graphene sheets. Small amounts of graphene (typically from 0.1% to 10% by weight) can be used instead of up to 70% by weight of these anti-corrosive pigment materials.

Claims

1. A graphene-based coating suspension comprising a plurality of graphene sheets each having two opposite parallel surfaces, a thin film coating of a corrosion-resistant pigment or sacrificial metal having a thickness from 0.5nm to 100nm applied to and covering at least 50% of the area of one of the two parallel surfaces, and a binder resin dissolved or dispersed in a liquid medium, wherein the plurality of graphene sheets contains a single layer or few layer graphene sheets selected from the group consisting of: a pristine graphene material having zero% non-carbon elements or a non-pristine graphene material having 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene material is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein the graphene sheets have a weight fraction of from 0.1% to 30% based on the weight of the total coating suspension excluding the liquid medium.

2. The coating suspension of claim 1 wherein the corrosion-inhibiting pigment or sacrificial metal is selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof.

3. The coating suspension of claim 1 wherein the corrosion-inhibiting pigment or sacrificial metal covers at least 80% of the area of one of the parallel surfaces.

4. The coating suspension of claim 1 wherein the binder resin comprises a resin selected from the group consisting of epoxy resins, polyurethane resins, urethane-urea resins, phenolic resins, acrylic resins, alkyd resins, polyimides, thermosetting polyesters, vinyl ester resins, silicate binders, or combinations thereof.

5. The coating suspension of claim 1, wherein the non-pristine graphene material has from 1% to 30% by weight of non-carbon elements selected from O, H, N, F, cl, br, I, B, P, or a combination thereof.

6. The coating suspension of claim 1, further comprising a carrier, filler, dispersant, surfactant, defoamer, catalyst, accelerator, stabilizer, coalescing agent, thixotropic agent, anti-settling agent, color dye, coupling agent, extender, conductive pigment, electronically conductive polymer, or a combination thereof.

7. The coating suspension of claim 6 wherein the conductive pigment is selected from acetylene black, carbon black, expanded graphite flakes, carbon fibers, carbon nanotubes, mica coated with antimony doped tin oxide or indium tin oxide, or mixtures thereof.

8. The coating suspension of claim 6 wherein the electronically conductive polymer is selected from the group consisting of: polydiacetylene, polyacetylene (PAc), polypyrrole (PPy), polyaniline (PAni), polythiophene (PTh), polyisothiaindene (PITN), polyheteroarylenevinylene (PArV) wherein the heteroarylene group is selected from thiophene, furan or pyrrole, polyparaphenylene (PpP), polyhalocyanine (PPhc) and derivatives thereof, and combinations thereof.

9. The coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: alkyl or aryl silanes, alkyl or aralkyl groups, hydroxy, carboxyl, amino, sulfonic acid (- -SO) ₃ H) An aldehyde group, a quinone group, a fluorocarbon, or a combination thereof.

10. The coating suspension of claim 1, wherein the chemically functionalized graphene comprises graphene sheets having a chemical functional group selected from the group consisting of derivatives of azide compounds selected from the group consisting of: 2-azidoethanol, 3-azidopropan-1-amine, 4- (2-azidoethoxy) -4-oxobutanoic acid, 2-azidoethyl-2-bromo-2-methylpropionate, azidoformates, and combinations thereof.

11. The coating suspension of claim 10, wherein the nitrene is (R-) -oxycarbonylnitrene, wherein R = any of the following groups:

12. the coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of oxygen-containing groups selected from the group consisting of: hydroxyl, peroxide, ether, ketone, and aldehyde.

13. The coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: SO (SO) ₃ H、COOH、NH ₂ OH, R 'CHOH, CHO, CN, COCl, halo, COSH, SH, COOR', SR ', siR' ₃ 、Si(--OR’--) _y R’ ₃ -y、Si(--O--SiR’ ₂ -)OR’、R”、Li、AlR’ ₂ 、Hg--X、TlZ ₂ And Mg- -X; wherein y is an integer equal to or less than 3, R' is hydrogen, alkyl, aryl, cycloalkyl or aralkyl, cycloaryl or polyalkylether, R "is fluoroalkyl, fluoroaryl, fluoroacycloalkyl, fluoroarylalkyl or cycloaryl, X is halo, and Z is carboxylate or trifluoroacetate, and combinations thereof.

14. The coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, polyamine epoxy adducts, phenolic hardeners, and combinations thereof.

15. The coating suspension of claim 14 wherein the aliphatic amine is a polyethylene polyamine.

16. The coating suspension of claim 15, wherein the polyethylene polyamine is selected from the group consisting of Diethylenetriamine (DETA), triethylenetetramine (TETA), and Tetraethylenepentamine (TEPA).

17. The coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from non-brominated curing agents and non-amine curing agents.

18. The coating suspension of claim 1 wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: OY, NHY, O=C-OY, O=C-SY or O=C-Y, and Y is a functional group of a protein, peptide, amino acid, enzyme, antibody, nucleotide, oligonucleotide, antigen, or transition state analogue of an enzyme substrate, enzyme inhibitor or enzyme substrate, or is selected from (C ₂ H ₄ O--) _w H or (- -C) ₃ H ₆ O--) _w H, and w is an integer greater than 1 and less than 200.

19. An object or structure at least partially coated with a coating comprising a plurality of graphene sheets and a binder resin, a thin coating of a corrosion-inhibiting pigment or sacrificial metal deposited on the graphene surface, the binder resin bonding the plurality of graphene sheets together and to the surface of the object or structure, wherein the plurality of graphene sheets contain single or few graphene sheets selected from the group consisting of: a pristine graphene material having zero% non-carbon elements or a non-pristine graphene material having 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene material is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein the graphene sheets have a weight fraction of from 0.1% to 30% based on the total coating weight.

20. The object or structure of claim 19, wherein the corrosion-resistant pigment or sacrificial metal is selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof.

21. The object or structure of claim 19, wherein the coating has a thickness of from 1nm to 1.0 mm.

22. The object or structure of claim 19, wherein the object or structure is metallic.

23. The object or structure of claim 19, wherein the binder resin comprises an ester resin, neopentyl glycol (NPG), ethylene Glycol (EG), isophthalic acid, terephthalic acid, a urethane resin, a urethane ester resin, an acrylic urethane resin, or a combination thereof.

24. The object or structure of claim 19, wherein the binder resin contains a curing agent and/or coupling agent in an amount of 1 to 30 parts by weight based on 100 parts by weight of the binder resin.

25. The object or structure of claim 19, wherein the binder resin comprises a thermally curable resin comprising a multifunctional epoxy monomer selected from the group consisting of: diglycidyl ether, dipentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, or a combination thereof.

26. The object or structure of claim 19, wherein the binder resin comprises a thermally curable resin comprising a difunctional or trifunctional epoxy monomer selected from the group consisting of: trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, tetraphenylolethane tetraglycidyl ether, p-aminophenol triglycidyl ether, 1,2, 6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycidyl triglycidyl ether, glycerol ethoxytriglycidyl ether, castor oil triglycidyl ether, propoxylated glycerol triglycidyl ether, ethylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated bisphenol a diglycidyl ether, 3, 4-epoxycyclohexylcarboxylic acid (3, 4-epoxycyclohexane) methyl ester, and mixtures thereof.

27. The object or structure of claim 19, wherein the binder resin comprises a UV radiation curable resin or a UV radiation curable lacquer selected from the group consisting of acrylate and methacrylate oligomers, (meth) acrylate, polyols and derivatives thereof having (meth) acrylate functionality, including ethoxylated trimethylol propane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate or neopentyl glycol di (meth) acrylate and mixtures thereof, and acrylate and methacrylate oligomers derived from: low molecular weight polyester resins, polyether resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, epoxy acrylates, polybutadiene resins, and polythiol-polyene resins.

28. The object or structure of claim 19, wherein the object or structure is a metal reinforcement material or member.

29. The object or structure of claim 19, wherein the object or structure is a concrete structure.

30. The object or structure of claim 19, wherein the object or structure is a bridge.

31. A method for producing the graphene-based coating suspension of claim 1, the method comprising:

a) Providing a continuous film of graphene sheets into a deposition zone;

b) Introducing vapor or atoms of a corrosion-inhibiting pigment or metal into the deposition zone and depositing the vapor or atoms onto the surface of the graphene sheets to form a coating film of corrosion-inhibiting material-coated graphene sheets;

c) Mechanically crushing the coating film into a plurality of graphene sheets coated with anti-corrosion materials; and

d) A plurality of sheets of corrosion-resistant material coated graphene sheets and a binder resin are dispersed in a liquid medium to form the coating suspension.

32. The method of claim 31, wherein the continuous film of graphene sheets is produced by spraying a graphene suspension onto a solid substrate and by removing a liquid medium, wherein the graphene suspension contains graphene sheets dispersed in the liquid medium.

33. The method of claim 31, wherein the continuous film of graphene sheets is produced by chemical vapor deposition of graphene material onto a solid substrate.

34. The method of claim 31, wherein the coating film has a corrosion-resistant active material coating thickness of less than 100 nm.

35. The method of claim 31, wherein the step (b) of forming a coating film of the corrosion-resistant material coated graphene sheets entails depositing a corrosion-resistant pigment or metal chemical vapor deposition, physical vapor deposition, sputtering, or laser-assisted thin film onto the continuous film of graphene sheets.

36. The method of claim 31, wherein the mechanically crushing step (c) requires air jet milling, impact milling, grinding, mechanical shearing, sonication, or a combination thereof.

37. The method of claim 31, wherein the step (a) of providing a continuous film of graphene sheets comprises feeding the continuous film from a feeder roll into the deposition zone, and step (b) further comprises collecting the coated film onto a take-up roll.

38. A method of inhibiting corrosion of a structure or object having a surface, the method comprising (i) coating at least a portion of the surface with a coating suspension comprising a plurality of graphene sheets dispersed or dissolved in a liquid medium and a binder resin, the graphene sheets being coated with a thin film of a corrosion-inhibiting pigment or sacrificial metal having a thickness of from 0.5nm to 1 μιη; and (ii) at least partially removing the liquid medium from the coating suspension after the step of coating is completed to form a protective coating on the surface.

39. The method of claim 38, wherein the anti-corrosive pigment or sacrificial metal is selected from aluminum, chromium, zinc, beryllium, magnesium, alloys thereof, zinc phosphate, or combinations thereof.

40. The method of claim 38, wherein the plurality of graphene sheets contains single-or few-layer graphene sheets selected from the group consisting of: a pristine graphene material having zero% non-carbon elements or a non-pristine graphene material having 0.001% to 47% non-carbon elements by weight, wherein the non-pristine graphene material is selected from graphene oxide, reduced graphene oxide, fluorinated graphene, chlorinated graphene, brominated graphene, iodinated graphene, hydrogenated graphene, nitrogenated graphene, doped graphene, chemically functionalized graphene, or a combination thereof, and wherein the graphene sheets have a weight fraction of from 0.1% to 30% based on the weight of the total coating suspension excluding the liquid medium.

41. The method of claim 40, wherein the non-native graphene material has from 1% to 30% by weight of non-carbon elements selected from O, H, N, F, cl, br, I, B, P, or a combination thereof.

42. The method of claim 38, wherein the binder resin comprises a resin selected from the group consisting of epoxy, polyurethane, urethane-urea, phenolic, acrylic, alkyd, polyimide, thermoset polyester, vinyl ester, silicate binder, or combinations thereof.

43. The method of claim 38, wherein the protective coating contains corrosion-resistant pigment or sacrificial metal-coated graphene sheets aligned parallel to each other and to the surface of the structure or object.

44. The method of claim 38, wherein the coating suspension further comprises a carrier, filler, dispersant, surfactant, defoamer, catalyst, accelerator, stabilizer, coalescing agent, thixotropic agent, anti-settling agent, color dye, coupling agent, extender, conductive pigment, electronically conductive polymer, or a combination thereof.

45. The method of claim 38, wherein the film of anti-corrosive pigment or sacrificial metal has a thickness from 0.5nm to 100nm and is coated on and covers at least 50% of the area of one of the two parallel surfaces of the graphene sheet.

46. The method of claim 38, wherein the film of corrosion-inhibiting pigment or sacrificial metal covers at least 80% of the area of one of the two parallel surfaces of the graphene sheet.

47. The method of claim 44, wherein the conductive pigment is selected from acetylene black, carbon black, expanded graphite flakes, carbon fibers, carbon nanotubes, mica coated with antimony doped tin oxide or indium tin oxide, or mixtures thereof.

48. The method of claim 44, wherein the electronically conductive polymer is selected from the group consisting of: polydiacetylene, polyacetylene (PAc), polypyrrole (PPy), polyaniline (PAni), polythiophene (PTh), polyisothiaindene (PITN), polyheteroarylenevinylene (PArV) wherein the heteroarylene group is selected from thiophene, furan or pyrrole, polyparaphenylene (PpP), polyhalocyanine (PPhc), and derivatives thereof, and combinations thereof.

49. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: alkyl or aryl silanes, alkyl or aralkyl groups, hydroxy, carboxyl, amino, sulfonic acid (- -SO) ₃ H) An aldehyde group, a quinone group, a fluorocarbon, or a combination thereof.

50. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having a chemical functional group selected from the group consisting of derivatives of azide compounds selected from the group consisting of: 2-azidoethanol, 3-azidopropan-1-amine, 4- (2-azidoethoxy) -4-oxobutanoic acid, 2-azidoethyl-2-bromo-2-methylpropionate, azidoformates, and combinations thereof.

51. The method of claim 50, wherein the nitrene is (R-) -oxycarbonylnitrene, wherein R = any one of the following groups

52. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of oxygen-containing groups selected from the group consisting of: hydroxyl, peroxide, ether, ketone, and aldehyde.

53. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: SO (SO) ₃ H、COOH、NH ₂ OH, R 'CHOH, CHO, CN, COCl, halo, COSH, SH, COOR', SR ', siR' ₃ 、Si(--OR’--) _y R’ ₃ -y、Si(--O--SiR’ ₂ -)OR’、R”、Li、AlR’ ₂ 、Hg--X、TlZ ₂ And Mg- -X; wherein y is an integer equal to or less than 3, R' is hydrogen, alkyl, aryl, cycloalkyl or aralkyl, cycloaryl or polyalkylether, R "is fluoroalkyl, fluoroaryl, fluoroacycloalkyl, fluoroarylalkyl or cycloaryl, X is halo, and Z is carboxylate or trifluoroacetate, and combinations thereof.

54. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: amidoamines, polyamides, aliphatic amines, modified aliphatic amines, cycloaliphatic amines, aromatic amines, anhydrides, ketimines, polyamine epoxy adducts, phenolic hardeners, and combinations thereof.

55. A process as set forth in claim 54 wherein said aliphatic amine is a polyethylene polyamine.

56. The method of claim 55, wherein the polyethylene polyamine is selected from the group consisting of Diethylenetriamine (DETA), triethylenetetramine (TETA), and Tetraethylenepentamine (TEPA).

57. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of non-brominated curing agents and non-amine curing agents.

58. The method of claim 40, wherein the chemically functionalized graphene comprises graphene sheets having chemical functional groups selected from the group consisting of: OY, NHY, O=C-OY, O=C-SY or O=C-Y, and Y is a functional group of a protein, peptide, amino acid, enzyme, antibody, nucleotide, oligonucleotide, antigen, or transition state analogue of an enzyme substrate, enzyme inhibitor or enzyme substrate, or is selected from (C ₂ H ₄ O--) _w H or (- -C) ₃ H ₆ O--) _w H, and w is an integer greater than 1 and less than 200.

59. The method of claim 38, wherein the binder resin contains a curing agent and/or coupling agent in an amount of 1 to 30 parts by weight based on 100 parts by weight of the binder resin.

60. The method of claim 38, wherein the binder resin comprises a thermally curable resin comprising a multifunctional epoxy monomer selected from the group consisting of: diglycidyl ether, dipentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, or a combination thereof.

61. The method of claim 38, wherein the binder resin comprises a thermally curable resin comprising a difunctional or trifunctional epoxy monomer selected from the group consisting of: trimethylolethane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triphenylolmethane triglycidyl ether, tetraphenylolethane tetraglycidyl ether, p-aminophenol triglycidyl ether, 1,2, 6-hexanetriol triglycidyl ether, glycerol triglycidyl ether, diglycidyl triglycidyl ether, glycerol ethoxytriglycidyl ether, castor oil triglycidyl ether, propoxylated glycerol triglycidyl ether, ethylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated bisphenol a diglycidyl ether, 3, 4-epoxycyclohexylcarboxylic acid (3, 4-epoxycyclohexane) methyl ester, and mixtures thereof.

62. The method of claim 38, wherein the binder resin comprises a UV radiation curable resin or a UV radiation curable lacquer selected from the group consisting of acrylate and methacrylate oligomers, (meth) acrylate, polyols and derivatives thereof having (meth) acrylate functionality, including ethoxylated trimethylol propane tri (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1, 6-hexanediol di (meth) acrylate or neopentyl glycol di (meth) acrylate, and mixtures thereof, and acrylates and methacrylate oligomers derived from: low molecular weight polyester resins, polyether resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, epoxy acrylates, polybutadiene resins, and polythiol-polyene resins.