A polyaniline nanocomposite for anticorrosive paint and a preparation method thereof, and a polyaniline composite anticorrosive paint

Abstract

The present application belongs to the technical field of anticorrosive paint in steel industry, and particularly relates to a polyaniline nanocomposite for anticorrosive paint and a preparation method thereof, and further relates to a polyaniline composite anticorrosive paint using the polyaniline nanocomposite as filler, and especially relates to a polyaniline composite paint for anticorrosion of general steel using the polyaniline nanocomposite as filler. The polyaniline nanocomposite prepared by the present application can effectively inhibit the agglomeration of graphene nanosheets and polyaniline through in-situ polymerization of polyaniline on the graphene nanosheets, and can form a grid structure in the base material through the lamellar structure of the polyaniline nanocomposite in the coating, further playing an effective barrier role in the diffusion of oxygen, water, chloride ions and the like, so that the coating can play a good shielding role on corrosive gases, and greatly improve the corrosion resistance of the metal surface.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anticorrosive coatings in the steel industry, and particularly relates to a polyaniline nanocomposite for anticorrosive coatings and a preparation method thereof, and further relates to a polyaniline composite anticorrosive coating using the polyaniline nanocomposite as a filler, and particularly relates to a polyaniline composite coating for anticorrosion of general steel materials using the polyaniline nanocomposite as a filler. BACKGROUND

[0002] Low-carbon steel, as an excellent material, has the characteristics of high tensile strength, low cost, excellent mechanical properties, etc., and becomes an important structural material applied in industrial engineering. Especially with the progress of the times and the development of industry, metal products are more and more widely used, but in the process of metal use, there are often serious metal corrosion problems. Corrosion can reduce the performance of metal materials and shorten the service life of metals, causing huge losses to the national economy every year. Corrosion control is particularly important for prolonging the service life of metal materials. At present, the protection of marine metal matrix is mainly achieved by using corrosion-resistant materials, metal surface modification, applying anticorrosive coatings and electrochemical protection, etc., among which, applying anticorrosive coatings is the most direct, effective and economical anticorrosion method. Generally speaking, the organic coating applied on the metal surface can form a physical barrier to delay the penetration of corrosive media such as water and oxygen, thereby prolonging the service life of the metal.

[0003] Epoxy resin coatings have the advantages of strong adhesion, high mechanical strength, good water resistance and excellent corrosion resistance, and are the most widely used anticorrosive coatings for steel substrates in shipbuilding and ocean engineering. However, due to the high cross-linking density of epoxy resin, some microcracks or pores often appear in the coating, and corrosive substances such as dissolved oxygen and chloride ions in water can penetrate into the metal substrate / coating interface through such defects, resulting in reduced corrosion resistance and adhesion of the coating. To solve this problem, the following methods can be used to improve the corrosion resistance of epoxy coatings: increasing the bending degree of the diffusion path of corrosive media, reducing the porosity of the epoxy coating, reducing the affinity of corrosive media and the epoxy coating, and inhibiting the reaction between corrosive media and the metal substrate. Nanomaterials are materials with at least one dimension in the nanometer scale. Due to the small particle size, nanomaterials have many excellent properties different from those of coarse-grained materials, including high strength, high hardness, low density, low elastic modulus, etc. Due to their special structure and properties, some researchers have directly used nanomaterials as corrosion inhibitors to alleviate metal corrosion. SUMMARY

[0004] In view of the defects of the prior art, the present application aims to provide a polyaniline nanocomposite for anticorrosive paint and a preparation method thereof, which can be used as a filler to prepare a polyaniline composite anticorrosive paint, and in particular, a polyaniline composite paint for general steel anticorrosion using the polyaniline nanocomposite as a filler.

[0005] To achieve the above-mentioned object, the present application adopts the following solutions:

[0006] In a first aspect, the present application provides a preparation method of a polyaniline nanocomposite for anticorrosive paint, comprising the following steps:

[0007] The mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles and a surfactant is uniformly dispersed in an acidic solution to obtain a dispersion liquid;

[0008] Aniline is added to the dispersion liquid under the condition of an ice water bath at a temperature of 0-4℃, and the reaction is stirred to obtain a reaction liquid;

[0009] The acidic solution and an initiator are mixed and stirred under the condition of an ice water bath at a temperature of 0-4℃ to obtain an initiator solution;

[0010] The initiator solution is added to the reaction liquid to cause a polymerization reaction, and a crude polyaniline nanocomposite is obtained;

[0011] The crude polyaniline nanocomposite is washed, dried and ground to obtain a polyaniline nanocomposite.

[0012] Preferably, the acidic solution is a hydrochloric acid solution; the surfactant is a fluorine-containing surfactant, preferably selected from one or more of potassium perfluorooctanoate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluorobutyl methacrylate, dodecafluoroheptyl acrylate, dodecafluoroheptyl methacrylate and tridecafluorooctyl methacrylate, and more preferably is potassium perfluorooctanoate; and the initiator is selected from one or more of ammonium persulfate, azobisisobutyronitrile, azobisisoheptyl nitrile, dibenzoyl peroxide and tert-butyl peroxybenzoate, and more preferably is ammonium persulfate.

[0013] Preferably, the mass ratio of the aniline, graphene nanosheet, Al2O3 / ATO mixed nanoparticles and mixed solvent is 1:(0.1-10):(0.1-10):(1-10), preferably 1:(0.1-5):(0.1-5):(5-10), wherein the weight of the mixed solvent = total weight of the solution when the polymerization reaction occurs - weight of the mixed powder containing the graphene nanosheet, Al2O3 / ATO mixed nanoparticles and surfactant - weight of the aniline; the mass ratio of Al2O3 and ATO in the Al2O3 / ATO nanoparticles is 1:(0.1-10), preferably 1:(0.1-5); the particle size of the Al2O3 / ATO nanoparticles is 20-100 nm, and the size of the graphene nanosheet is 1-10 μm.

[0014] Preferably, the steps of washing, drying and grinding the crude polyaniline nanocomposite material include: washing with ethanol for 2-4 times, washing with distilled water until the filtrate is neutral, drying in a constant temperature oven at 75-85°C for 10-15 h, and then putting into a ball mill and grinding at a speed of 180-280 rpm for 10-15 h.

[0015] In a second aspect, the present application further provides a polyaniline nanocomposite material for anticorrosive coating prepared by the preparation method as described above.

[0016] Preferably, the polyaniline composite nanomaterial comprises graphene nanosheet, Al2O3 / ATO mixed nanoparticles and polyaniline which is polymerized in situ on the surface of the graphene nanosheet.

[0017] Preferably, the polyaniline composite nanomaterial further comprises a surfactant; the surfactant is a fluorine-containing surfactant, preferably selected from one or more of potassium perfluorooctanoate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluorobutyl methacrylate, dodecafluoroheptyl acrylate, dodecafluoroheptyl methacrylate and tridecafluorooctyl methacrylate, more preferably potassium perfluorooctanoate.

[0018] In a third aspect, the present application further provides a polyaniline composite anticorrosive coating, which is prepared by adding the polyaniline nanocomposite material as described above to a polymer matrix resin as a filler; wherein the addition amount of the polyaniline nanocomposite material is 0.5%-10%.

[0019] Preferably, the polymer matrix resin is selected from any one of a silicone-acrylate emulsion, an epoxy resin, a polyurethane, a polyacrylate and an alkyd resin.

[0020] Fourthly, the present invention also provides a polyaniline composite coating for corrosion protection of general-purpose steel, wherein the preparation method of the polyaniline composite coating for corrosion protection of general-purpose steel includes the following steps:

[0021] Step (1): Weigh 18-22g of potassium silicate solution with a modulus of 2.7 and add it to a 100mL beaker. Keep the temperature constant at 45-55℃ and stir. Add 8-10g of alkaline silica sol and 4-8g of deionized water dropwise. Stir for 30-50min and cool to room temperature to obtain potassium silicate base material. Add 10-15g of deionized water and 10-14g of 25% silicone acrylic emulsion to it. Stir and react at 30℃ for 20-40min. Cool to room temperature to obtain silicone acrylic emulsion modified potassium silicate base material.

[0022] Step (2): Take 10.0g of silicone-acrylic emulsion modified potassium silicate and add it to a 100mL beaker and stir. Add the following components: 0.1%-5% silane coupling agent (based on the mass of silicone-acrylic emulsion modified potassium silicate, the same below), EFKA-2722 0.1%-5%, EFKA3777 0.1%-5%, sodium carboxymethyl cellulose 0.4%-0.6%, and stir thoroughly for 20-60min until there are no lumps. Then add the polyaniline nanocomposite material as described above at an addition amount of 0.5%-10%. Finally, add 0.1%-5% zinc powder so that the zinc powder and the base material obtained by adding the components are mixed in proportion. Continue stirring for 40-80min until the coating is uniformly mixed to obtain a polyaniline composite coating for corrosion protection of general steel.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention provides a polyaniline nanocomposite material for anti-corrosion coatings and its preparation method. The polyaniline nanocomposite material can be used as a filler to prepare polyaniline composite anti-corrosion coatings. More particularly, this invention provides a polyaniline composite coating for general steel corrosion protection using the polyaniline nanocomposite material as a filler. The polyaniline nanocomposite material prepared by this invention effectively inhibits the agglomeration of graphene nanosheets and polyaniline through in-situ polymerization of polyaniline on graphene nanosheets. Furthermore, the layered structure of the polyaniline nanocomposite material in the coating forms a mesh structure in the base material, further effectively blocking the diffusion of oxygen, water, chloride ions, etc., thus providing excellent shielding against corrosive gases and greatly improving the corrosion resistance of metal surfaces. Attached Figure Description

[0025] Figure 1 The image shows a SEM image of the polyaniline nanocomposite material involved in this invention; in the image, (a) is alumina nanoparticles, (b) is graphene nanosheets, and (c) is polyaniline nanocomposite material powder.

[0026] Figure 2 The figure shows the coating polarization curves of the polyaniline composite coating for corrosion protection of general steel prepared in the embodiments of the present invention; in the figure, (a) is graphene nanosheets: (1Al2O3 / 1ATO): aniline: mixed solvent = 0:0:1:9; (b) is graphene nanosheets: (1Al2O3 / 2ATO): aniline: mixed solvent = 0:1:1:9; (c) is graphene nanosheets: (3Al2O3 / 1ATO): aniline: mixed solvent = 1:1:1:8. Detailed Implementation

[0027] Polyaniline nanocomposites for use in anti-corrosion coatings

[0028] This invention provides a polyaniline nanocomposite material for anti-corrosion coatings, the preparation method of which includes the following steps:

[0029] Step (1): Add 1.0 mol / L hydrochloric acid solution and a mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles and surfactant to a round-bottom flask. Disperse the mixture ultrasonically for 60-90 min. Slowly add aniline dropwise under ice-water bath conditions (temperature maintained at 0-4℃) and stir for 45-90 min to obtain the reaction solution.

[0030] Figure 1 SEM images of Al2O3 / ATO mixed nanoparticles (a), graphene nanosheets (b), and polyaniline nanocomposite powder (c) are presented. From... Figure 1 It can be seen that the particle size of the Al2O3 / ATO mixed nanoparticles is approximately 20-100 nm, and the size of the graphene nanosheets is approximately 1-10 μm. Figure 1 (c) It can also be seen that polyaniline, which has undergone in-situ polymerization, is attached to the surface of the graphene nanosheets.

[0031] In this step, as a preferred embodiment, the surfactant is a fluorinated surfactant, including but not limited to potassium perfluorooctanoate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluorobutyl methacrylate, dodecafluoroheptyl acrylate, dodecafluoroheptyl methacrylate, or tridecafluorooctyl methacrylate. In this embodiment of the invention, potassium perfluorooctanoate is used as an example.

[0032] Step (2): Mix and stir 1.0 mol / L hydrochloric acid solution and initiator for 15-30 min under ice-water bath conditions (temperature maintained at 0-4℃) to obtain initiator solution.

[0033] In this step, as a preferred embodiment, the initiator includes, but is not limited to, ammonium persulfate, azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide or tert-butyl peroxide. In this embodiment of the invention, ammonium persulfate is used as an example.

[0034] In this step, as a preferred embodiment, the mass concentration of the initiator in the initiator solution is (1-10) g / mL, more preferably (1-5) g / mL, for example, it can be 1.5 g / mL, 2 g / mL, 2.5 g / mL, 3 g / mL, 3.5 g / mL, 4 g / mL, or 4.5 g / mL.

[0035] Step (3): Add the initiator solution to the reaction solution obtained in step (1) at a rate of 1 drop every 1-2 seconds, and perform the polymerization reaction for 18-26 hours to obtain crude polyaniline nanocomposite material.

[0036] Step (4) involves washing, drying, and grinding the crude polyaniline nanocomposite material, including: washing with ethanol 2-4 times, then washing with distilled water until the filtrate is neutral, drying in a constant temperature oven at 75-85℃ for 10-15 hours, and then grinding in a ball mill at a speed of 180-280 rpm for 10-15 hours to obtain the polyaniline nanocomposite material of the present invention.

[0037] In a preferred embodiment, the mass ratio of aniline, graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and mixed solvent is 1:(0.1-10):(0.1-10):(1-10), preferably 1:(0.1-5):(0.1-5):(5-10), wherein the weight of the mixed solvent = the total weight of the solution during the polymerization reaction - the weight of the mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and surfactant - the weight of aniline; in the Al2O3 / ATO nanoparticles, the mass ratio of Al2O3 to ATO is 1:(0.1-10), preferably 1:(0.1-5).

[0038] The polyaniline composite nanomaterial prepared by the above preparation method of the present invention includes graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and polyaniline that undergoes in-situ polymerization on the surface of the graphene nanosheets, and also includes the surfactant as described above.

[0039] <Polyaniline Composite Anti-corrosion Coating>

[0040] The present invention also provides a polyaniline composite anti-corrosion coating, which is prepared by adding the polyaniline nanocomposite material as described above as a filler to a polymer matrix resin; wherein the amount of the polyaniline nanocomposite material added is 0.5%-10% (for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%).

[0041] In a preferred embodiment, the polymer matrix resin may be selected from resin systems well known in the art, such as, but not limited to, silicone-acrylic emulsions, epoxy resins, polyurethanes, polyacrylates, or alkyd resins.

[0042] In a preferred embodiment, the polyaniline composite anticorrosive coating further includes additives well known in the art, such as, but not limited to, emulsifiers, defoamers, antifoaming agents, dispersants, wetting agents, leveling agents, or thickeners.

[0043] Polyaniline composite coatings for corrosion protection of general-purpose steel

[0044] This invention also provides a polyaniline composite coating for corrosion protection of general-purpose steel, the preparation method of which includes the following steps:

[0045] S1. Weigh 18-22g of potassium silicate solution with a modulus of 2.7 and add it to a 100mL beaker. Keep the temperature constant at 45-55℃ and stir. Add 8-10g of alkaline silica sol and 4-8g of deionized water dropwise. Stir for 30-50min and cool to room temperature to obtain potassium silicate base material. Add 10-15g of deionized water and 10-14g of 25% silicone acrylic emulsion to it. Stir and react at 30℃ for 20-40min. Cool to room temperature to obtain silicone acrylic emulsion modified potassium silicate base material.

[0046] S2, add 10.0g of silicone-acrylic emulsion modified potassium silicate to a 100mL beaker and stir. Add the following components: 0.1%-5% silane coupling agent (based on the mass of silicone-acrylic emulsion modified potassium silicate, the same below), EFKA-2722 0.1%-5%, EFKA3777 0.1%-5%, sodium carboxymethyl cellulose 0.4%-0.6%, and stir thoroughly for 20-60min until there are no lumps. Then add the polyaniline nanocomposite material as described above at an addition amount of 0.5%-10%. Finally, add 0.1%-5% zinc powder so that the zinc powder and the base material obtained by adding the components are mixed in proportion. Continue stirring for 40-80min until the coating is uniformly mixed to obtain a polyaniline composite coating for corrosion protection of general steel.

[0047] According to the present invention, the above-mentioned polyaniline composite coating of the present invention is applied to the surface of metal such as general steel by means of spin coating or sputtering, especially using the polyaniline nanocomposite material of the present invention as a filler, wherein the polyaniline composite nanomaterial includes graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and polyaniline that undergoes in-situ polymerization reaction on the surface of the graphene nanosheets.

[0048] Graphene nanosheets possess high specific surface area, excellent electrical conductivity and chemical stability, and outstanding mechanical properties. They exhibit strong impermeability and can be used as fillers to fill the micropores of coatings, effectively improving the barrier properties of anti-corrosion coatings, clearing conductive pathways, and enhancing the effect of nanoparticles, thereby improving the coating's corrosion resistance. However, due to their high specific surface area, they are prone to aggregation in solution. Polyaniline, as a conductive polymer material, offers advantages over other inorganic fillers, including simple synthesis, low cost, excellent acid doping properties, and unique redox characteristics. It can form an oxide layer on metal surfaces, protecting them from further corrosion. However, its conjugated structure and unsaturated chemical bonds in its molecules also make it prone to aggregation under certain conditions.

[0049] The polyaniline nanocomposite material prepared by this invention effectively inhibits the agglomeration of graphene nanosheets and polyaniline through in-situ polymerization of polyaniline on graphene nanosheets. Furthermore, the layered structure of the polyaniline nanocomposite material in the coating forms a mesh structure within the base material, further effectively blocking the diffusion of oxygen, water, chloride ions, etc. When a metal surface coated with the polyaniline composite coating of this invention comes into contact with corrosive gases, such as acidic or alkaline gases, or moisture, the coating provides excellent shielding, preventing corrosion of the metal surface. Simultaneously, the metal surface coated with the polyaniline composite coating of this invention also exhibits self-cleaning properties.

[0050] In the polyaniline nanocomposite material prepared by this invention, Al2O3 in the inorganic oxide Al2O3 / ATO mixed nanoparticles has been extensively studied for its excellent properties in electrical, optical, photocatalytic, biological, and mechanical fields, and it can improve the corrosion resistance and wear resistance of polymer coatings. Nano-ATO (Antimony Doped Tin Oxide) particles have a particle size of 10 nm or larger and exhibit an ellipsoidal structure. Due to their high conductivity, thermal insulation, and durability, they have broad application prospects in many fields. In the composite coating of this invention, they play an effective filling role, thereby improving the density of the coating and enabling it to exhibit excellent corrosion resistance in both acidic and alkaline environments.

[0051] Table 1 lists the water contact angles of polyaniline composite coatings for corrosion protection of general steel prepared using graphene nanosheets, Al2O3 / ATO mixed nanoparticles, aniline, and mixed solvents in different mass ratios.

[0052] Table 1

[0053]

[0054] In Table 1, the weight of the mixed solvent = the total weight of the solution during the polymerization reaction - the weight of the mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles and surfactant - the weight of aniline. In sample number 1, 1Al2O3 / 1ATO represents a mass ratio of Al2O3 to ATO of 1:1 (this explanation applies to the materials of other sample numbers in Table 1, and the same applies below).

[0055] As a specific implementation process, a certain proportion of the polyaniline composite coating of this invention for corrosion protection of general-purpose steel is applied to the metal surface, and the surface is placed in a specific environment to observe the corrosion. Generally speaking, the corrosion potential E corr A higher value indicates a lower thermodynamic corrosion tendency and better corrosion resistance; corr The lower the value, the lower the corrosion kinetic rate and the better the corrosion resistance. corr The value is the result of extrapolating the anode curve. (via I) corr The protective efficiency of the composite coating on the material was calculated.

[0056] Figure 2 The polarization curves of the polyaniline composite coating for corrosion protection of general steel prepared according to the embodiments of the present invention are given; in the figure, (a) is graphene nanosheets: (1Al2O3 / 1ATO): aniline: mixed solvent = 0:0:1:9 (sample number 1); (b) is graphene nanosheets: (1Al2O3 / 2ATO): aniline: mixed solvent = 0:1:1:9 (sample number 7); (c) is graphene nanosheets: (3Al2O3 / 1ATO): aniline: mixed solvent = 1:1:1:8 (sample number 19).

[0057] from Figure 2As can be seen, compared with the paint film obtained by adding only aniline without adding graphene nanosheets and Al2O3 / ATO (a), the corrosion resistance of the paint films obtained by adding only aniline (b) 1Al2O3 / 2ATO and (c) 3Al2O3 / 1ATO is significantly improved. This may be because when only aniline is added, the paint film only has the passivation effect of polyaniline, while after combining graphene nanosheets and Al2O3 / ATO with aniline, the paint film has better corrosion resistance due to the barrier effect of the graphene sheet structure. Moreover, among (b) the polyaniline nanocomposite with 1Al2O3 / 2ATO and (c) the polyaniline nanocomposite with graphene nanosheets and 3Al2O3 / 1ATO, the polyaniline nanocomposite with graphene nanosheets and 3Al2O3 / 1ATO in (c) has a relatively lower corrosion current density, indicating that it has better corrosion resistance than (b). It also shows that increasing the content of ATO nanoparticles can further improve the corrosion resistance of the coating.

[0058] The technical solution of the present invention will be further described below with reference to specific embodiments; however, the scope of protection of the present invention is not limited to these embodiments. All changes or equivalent substitutions that do not depart from the concept of the present invention are included within the scope of protection of the present invention.

[0059] Example 1 (Sample No. 1):

[0060] (1) Preparation of polyaniline nanocomposites:

[0061] 1) Add 100 mL of 1.0 mol / L hydrochloric acid solution and 0.1 g of mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles and surfactant potassium perfluorooctanoate to a round-bottom flask. Disperse the mixture by ultrasonication for 60-90 min. Slowly add aniline dropwise under ice-water bath conditions (temperature maintained at 0-4℃) and stir for 45-90 min to obtain the reaction solution.

[0062] 2) Under ice-water bath conditions (temperature maintained at 0-4℃), mix and stir 20mL of 1.0mol / L hydrochloric acid solution and 2.6g of initiator ammonium persulfate for 15-30min to obtain initiator solution;

[0063] 3) Add the initiator solution dropwise to the reaction solution obtained in step 1) at a rate of 1 drop every 1-2 seconds, and allow the polymerization reaction to proceed for 18-26 hours to obtain crude polyaniline nanocomposite material;

[0064] 4) Wash three times with ethanol, then wash with distilled water until the filtrate is neutral, and dry in a constant temperature oven at 75-85℃ for 10-15 hours;

[0065] 5) Place it in a ball mill and grind it at a speed of 180-280 rpm for 10-15 hours to obtain polyaniline nanocomposite material.

[0066] In the preparation process of the above polyaniline nanocomposite material, the mass ratio of graphene nanosheets: (1Al2O3 / 1ATO): aniline: mixed solvent is 0:0:1:9.

[0067] (2) Preparation of polyaniline composite coatings for corrosion protection of general steel:

[0068] 1) Weigh 18-22g of potassium silicate solution with a modulus of 2.7 and add it to a 100mL beaker. Keep the temperature constant at 45-55℃ and stir. Add 8-10g of alkaline silica sol and 4-8g of deionized water dropwise. Stir for 30-50min and cool to room temperature to obtain potassium silicate base material. Add 10-15g of deionized water and 10-14g of 25% silicone acrylic emulsion to it. Stir and react at 30℃ for 20-40min. Cool to room temperature to obtain silicone acrylic emulsion modified potassium silicate base material.

[0069] 2) Take 10.0g of silicone acrylic emulsion modified potassium silicate and add it to a 100mL beaker and stir. Add the following components: 2% silane coupling agent (based on the mass of silicone acrylic emulsion modified potassium silicate, the same below), 1% Efka EFKA-2722, 1% EFKA3777, 0.4%-0.6% sodium carboxymethyl cellulose. Stir thoroughly for 20-60min until there are no lumps. Then add the polyaniline nanocomposite material prepared above (1) at an addition amount of 1%. Finally, add 0.05g zinc powder so that the zinc powder and the base material obtained by adding the components are mixed in proportion. Continue stirring for 40-80min until the coating is mixed evenly to obtain a polyaniline composite coating for general steel corrosion protection.

[0070] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 42°, and the polarization curve parameters are E... corr (V) = -0.422, I corr (10 -6 A·cm -2 The coefficient of performance (COP) was 7.878, CorrRate (mil / year) was 3.661, and the protection efficiency was 40.53%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 3 days of immersion and after 3 days of salt spray testing. This was 2 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0071] Example 2 (Sample No. 4):

[0072] The preparation process of the polyaniline nanocomposite material and the preparation process of the polyaniline composite coating for corrosion protection of general steel in this embodiment are the same as those in Example 1. The difference is that in the preparation process of the polyaniline nanocomposite material, the mass ratio of graphene nanosheets:(1Al2O3 / 1ATO):aniline:mixed solvent is 1:1:1:8.

[0073] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 71°, and the polarization curve parameters are E... corr (V) = -0.419, I corr (10 -6 A·cm -2 The coefficient of performance (COP) was 7.097, CorrRate (mil / year) was 3.663, and the protection efficiency was 41.22%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 3 days of immersion and after 3 days of salt spray testing. This was 2 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0074] Example 3 (Sample No. 13):

[0075] The preparation process of the polyaniline nanocomposite material and the preparation process of the polyaniline composite coating for corrosion protection of general steel in this embodiment are the same as those in Example 1. The difference is that in the preparation process of the polyaniline nanocomposite material, the mass ratio of graphene nanosheets:(2Al2O3 / 1ATO):aniline:mixed solvent is 1:1:1:9.

[0076] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 83°, and the polarization curve parameters are E... corr (V) = -0.380, I corr (10 -6 A·cm -2 The coefficient of performance (COP) is 6.687, CorrRate (mil / year) is 3.055, and the protection efficiency is 49.99%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 7 days of immersion and after 7 days of salt spray testing. This was 6 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0077] Example 4 (Sample No. 14):

[0078] The preparation process of the polyaniline nanocomposite material and the preparation process of the polyaniline composite coating for corrosion protection of general steel in this embodiment are the same as those in Example 1. The difference is that in the preparation process of the polyaniline nanocomposite material, the mass ratio of graphene nanosheets:(2Al2O3 / 1ATO):aniline:mixed solvent is 1:1:1:8.

[0079] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 82°, and the polarization curve parameters are E... corr (V) = -0.390, I corr (10 -6 A·cm -2 The coefficient of performance (COP) was 6.098, CorrRate (mil / year) was 2.467, and the protection efficiency was 60.22%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 7 days of immersion and after 7 days of salt spray testing. This was 6 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0080] Example 5 (Sample No. 17):

[0081] The preparation process of the polyaniline nanocomposite material and the preparation process of the polyaniline composite coating for corrosion protection of general steel in this embodiment are the same as those in Example 1. The difference is that in the preparation process of the polyaniline nanocomposite material, the mass ratio of graphene nanosheets:(3Al2O3 / 1ATO):aniline:mixed solvent is 0:1:1:9.

[0082] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 88°, and the polarization curve parameters are E... corr (V) = -0.346, I corr (10 -6 A·cm -2 The coefficient of performance (COP) is 2.777, CorrRate (mil / year) is 1.229, and the protection efficiency is 79.33%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 13 days of immersion and after 12 days of salt spray testing. This was 10 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0083] Example 6 (Sample No. 18):

[0084] The preparation process of the polyaniline nanocomposite material and the preparation process of the polyaniline composite coating for corrosion protection of general steel in this embodiment are the same as those in Example 1. The difference is that in the preparation process of the polyaniline nanocomposite material, the mass ratio of graphene nanosheets:(3Al2O3 / 1ATO):aniline:mixed solvent is 1:1:1:9.

[0085] The polyaniline composite coating for corrosion protection of general-purpose steel prepared in this embodiment has a measured water contact angle of 86°, and the polarization curve parameters are E... corr (V) = -0.398, I corr (10-6 A·cm -2 The coefficient of performance (COP) is 3.029, CorrRate (mil / year) is 2.330, and the protection efficiency is 79.33%. Corrosion tests showed that the steel surface coated with this paint developed rust spots after 12 days of immersion and after 12 days of salt spray testing. This was 10 days longer than the time it took for uncoated steel surfaces to develop rust spots under the same conditions.

[0086] The test data for Examples 1-6 are listed in Tables 2 and 3.

[0087] Table 2

[0088]

[0089] Table 3

[0090]

[0091] As shown in Table 2, compared with Example 2, under the same conditions, the addition of graphene nanosheets and Al2O3 / ATO nanoparticles slightly increased the corrosion potential of the coating, while the corrosion rate remained roughly the same. Compared with Example 4, under the same conditions, increasing the amount of mixed solvent slightly increased the corrosion potential of the coating, while decreasing the corrosion rate. Compared with Example 5 and Example 6, under the same conditions, the addition of graphene nanosheets increased the corrosion potential of the coating, while decreasing the corrosion rate. Compared with Example 4, under the same conditions, reducing the ATO content in Al2O3 / ATO nanoparticles slightly increased the corrosion potential of the coating, but significantly decreased the corrosion rate. Compared with Example 6, under the same conditions, further reducing the ATO content in Al2O3 / ATO nanoparticles did not significantly change the corrosion potential of the coating, but slightly decreased the corrosion rate. This is because the ellipsoidal structure of ATO powder plays an effective filling role in the coating, and the good rigidity of the spherical particles increases the density and strength of the coating, thus improving the impedance of the composite coating.

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyaniline nanocomposite material for anti-corrosion coatings, characterized in that, Includes the following steps: A dispersion was obtained by uniformly dispersing a mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles and surfactants in an acidic solution. Aniline was added to the dispersion under ice-water bath conditions at 0-4°C, and the mixture was stirred to obtain a reaction solution. An acidic solution and an initiator are mixed and stirred under ice-water bath conditions at a temperature of 0-4°C to obtain an initiator solution. The initiator solution is added to the reaction solution to initiate a polymerization reaction, yielding a crude polyaniline nanocomposite material. The crude polyaniline nanocomposite material is washed, dried, and ground to obtain the polyaniline nanocomposite material.

2. The preparation method according to claim 1, characterized in that, The acidic solution is a hydrochloric acid solution; the surfactant is a fluorinated surfactant selected from one or more of potassium perfluorooctanoate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluorobutyl methacrylate, dodecafluoroheptyl acrylate, dodecafluoroheptyl methacrylate, and tridecafluorooctyl methacrylate; the initiator is selected from one or more of ammonium persulfate, azobisisobutyronitrile, azobisisoheptyl nitrile, benzoyl peroxide, and tert-butyl peroxide.

3. The preparation method according to claim 1, characterized in that, The mass ratio of aniline, graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and mixed solvent is 1:(0.1-10):(0.1-10):(1-10), wherein the weight of the mixed solvent = the total weight of the solution during the polymerization reaction - the weight of the mixed powder containing graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and surfactant - the weight of aniline; in the Al2O3 / ATO mixed nanoparticles, the mass ratio of Al2O3 to ATO is 1:(0.1-10); the particle size of the Al2O3 / ATO nanoparticles is 20-100 nm, and the size of the graphene nanosheets is 1-10 µm.

4. The preparation method according to claim 1, characterized in that, The steps of washing, drying and grinding the crude polyaniline nanocomposite material include: washing with ethanol 2-4 times, then washing with distilled water until the filtrate is neutral, drying in a constant temperature oven at 75-85°C for 10-15 hours, and then grinding in a ball mill at a speed of 180-280 rpm for 10-15 hours.

5. A polyaniline nanocomposite material for use in anti-corrosion coatings, prepared by the preparation method according to any one of claims 1-4.

6. The polyaniline nanocomposite material for anti-corrosion coatings according to claim 5, characterized in that, The polyaniline nanocomposite material includes graphene nanosheets, Al2O3 / ATO mixed nanoparticles, and polyaniline that undergoes in-situ polymerization on the surface of the graphene nanosheets.

7. The polyaniline nanocomposite material for anti-corrosion coatings according to claim 6, characterized in that, The polyaniline nanocomposite material further includes a surfactant; the surfactant is a fluorinated surfactant selected from one or more of potassium perfluorooctanoate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, trifluorobutyl methacrylate, dodecafluoroheptyl acrylate, dodecafluoroheptyl methacrylate, and tridecafluorooctyl methacrylate.

8. A polyaniline composite anti-corrosion coating, characterized in that, By adding the polyaniline nanocomposite material as described in any one of claims 5-7 to the polymer matrix resin, a polyaniline composite anti-corrosion coating can be prepared; wherein the amount of the polyaniline nanocomposite material added is 0.5%-10%.

9. The polyaniline composite anti-corrosion coating according to claim 8, characterized in that, The polymer matrix resin is selected from any one of silicone-acrylic emulsion, epoxy resin, polyurethane, polyacrylate and alkyd resin.

10. A polyaniline composite coating for corrosion protection of general-purpose steel, characterized in that, The preparation method of the polyaniline composite coating for corrosion protection of general steel includes the following steps: Step (1): Weigh 18-22g of potassium silicate solution with a modulus of 2.7 and add it to a 100mL beaker. Keep the temperature constant at 45-55℃ and stir. Add 8-10g of alkaline silica sol and 4-8g of deionized water dropwise. Stir for 30-50min and cool to room temperature to obtain potassium silicate base material. Add 10-15g of deionized water and 10-14g of 25% silicone acrylic emulsion to it. Stir and react at 30℃ for 20-40min. Cool to room temperature to obtain silicone acrylic emulsion modified potassium silicate base material. Step (2): Take 10.0g of silicone-acrylic emulsion modified potassium silicate base material and add it to a 100mL beaker and stir. Based on the mass of silicone-acrylic emulsion modified potassium silicate base material, add the following components: 0.1%-5% silane coupling agent, 0.1%-5% Evka EFKA-2722, 0.1%-5% EFKA3777, and 0.4%-0.6% sodium carboxymethyl cellulose. Stir thoroughly for 20-60min until there are no lumps. Then add the polyaniline nanocomposite material as described in any one of claims 5-7 at an addition amount of 0.5%-10%. Finally, add 0.1%-5% zinc powder so that the zinc powder is mixed with other components in proportion. Continue stirring for 40-80min until the coating is uniformly mixed to obtain a polyaniline composite coating for corrosion protection of general steel.

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