A high-efficiency anti-corrosion coating containing polyelectrolyte brush and preparation method thereof

Abstract

The invention discloses a kind of high-efficiency anticorrosive coating containing polyelectrolyte brush and preparation method thereof, comprise the film-forming material of water-based epoxy resin and curing agent and the nano-reinforced filler of spherical electrolyte brush, wherein the polyelectrolyte brush addition amount is 0.01-1wt.% of the anticorrosive coating. The present invention helps to form "maze effect" to suppress the diffusion of corrosion ions, and the carboxyl group of the polyacrylic acid of the bristle of polyelectrolyte brush will improve the crosslinking density of water-based epoxy resin and reduce the porosity of water-based epoxy resin under the promotion of amine curing agent. At the same time, polyelectrolyte brush has many and dense bristles, which helps to better improve the crosslinking density of water-based epoxy resin, thereby significantly improving the corrosion resistance of water-based epoxy resin. In addition, the structural designability of polyelectrolyte brush is strong, and the multifunctionalization of coating can be achieved by designing the structure of polyelectrolyte brush or loading different functional additives.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion coatings, and in particular to a high-efficiency anti-corrosion coating containing a polyelectrolyte brush and a preparation method thereof. Background Art

[0002] Metal plays a vital role in many industrial sectors, such as construction, transportation, and bridges, and is an essential component of modern industry and life. However, during use, metals are subject to environmental influences, inevitably subjecting them to corrosion. This corrosion not only impacts various sectors of the national economy but is also closely linked to public safety. Among various metal corrosion prevention measures, metal spray-coated polymer anti-corrosion coatings are one of the most common, convenient, and effective. Due to their high molecular weight, polymers exhibit high water repellency, effectively isolating corrosive media, particularly preventing water ingress. This effectively separates corrosive media from metal, preventing contact between the two and ultimately protecting the metal. According to a 2022 report by British media BBC Research (http: / / www.bbcresearch.com), the global anti-corrosion coating market is projected to grow from $28.4 billion in 2022 to $34 billion in 2027. Epoxy resins are thermosetting resins with high crosslink density and excellent shielding properties. The presence of numerous electronegative atoms, such as oxygen and nitrogen, creates strong intermolecular forces with metal substrates, enhancing coating adhesion. Epoxy resins are also chemically stable and readily form an inert film on metal surfaces, garnering widespread attention in the corrosion protection field. However, conventional solvent-based epoxy resins (EP) can cause serious air pollution and ecological problems, negatively impacting public health and the environment. Waterborne epoxy resins (WEPs) can address these environmental shortcomings, but the high porosity generated during curing significantly reduces WEP's corrosion resistance. Prior art methods often incorporate nanomaterials such as graphene, hydrotalcite, MXene, and silica into WEP coatings to enhance their corrosion resistance through barrier effects and the introduction of corrosion inhibitors. For example, Chinese invention patent application CN202111498014.7 discloses an anti-corrosion coating containing HATN@graphene and its preparation method. The method uses HANT to modify graphene and introduces it into waterborne epoxy resin to prepare an anti-corrosion coating containing HATN@graphene. X(MXene) / polyaniline water-based anti-corrosion coating and its preparation method. This method generates polyaniline in situ on the MXene surface, thereby suppressing the tendency of MXene to agglomerate in the epoxy resin matrix, improving the compatibility of MXene in the epoxy matrix, and combining with the passivation effect of polyaniline to improve the anti-corrosion performance of the water-based coating. The above-mentioned method suppresses the agglomeration tendency of nanomaterials by modifying the nanomaterials, improves the compatibility of nanomaterials with the water-based resin matrix, and avoids the problem that the porosity of the coating cannot be effectively reduced and the shielding effect cannot be fully exerted due to poor compatibility in practical applications. However, it can only provide very limited help in improving the cross-linking density of the coating. Chinese invention patent application CN202210361130.2 discloses a method for preparing an oxazolidine latent curing agent, and Chinese invention patent application CN202210344937.5 discloses a method for preparing a multi-functional oxazolidine latent curing agent. These latent curing agents are very helpful in increasing the crosslinking density, but they lack the "shielding effect" and "maze effect" that nanomaterials can provide. The present invention innovatively applies polymer electrolyte brush nanomaterials to the field of corrosion protection, combining the three functions of "shielding effect", "maze effect" and "increasing crosslinking degree" through polymer electrolyte brushes, and ultimately invents a high-efficiency anti-corrosion coating containing polyelectrolyte brushes and its preparation method. The so-called polyelectrolyte brush refers to a polymer brush in which the grafted polymer chain is a polyelectrolyte. Compared with ordinary polymer brushes, due to the steric hindrance and electrostatic effects between the polymer chains, polyelectrolyte brushes have better outward extension and stability. In the present invention, the polyelectrolyte brush with PS as the core and PAA as the bristles has excellent compatibility in the epoxy resin system, effectively helps to form a "maze effect" and inhibit the diffusion of corrosive ions. In addition, the polyacrylic acid in the bristles of the polyelectrolyte brush can act as a latent curing agent and react with the water-based epoxy resin under the promotion of amine curing agents, further increasing the crosslinking density of the water-based epoxy resin and reducing the porosity of the water-based epoxy resin. The polyelectrolyte brushes also have numerous and dense bristles, which help to increase the crosslink density of the waterborne epoxy resin, significantly improving its corrosion resistance. Furthermore, the polyelectrolyte brushes offer a highly designable structure. By tailoring the brush structure or loading it with different functional additives, the porosity of the coating can be reduced and its multifunctionality achieved. Therefore, this invention innovatively utilizes a small amount of polyelectrolyte brushes to modify waterborne epoxy resins, which has both research significance and industrial value. Summary of the Invention

[0003] The present invention aims to provide a highly effective anticorrosive coating containing polyelectrolyte brushes and a method for preparing the same. The spherical polyelectrolyte brushes exhibit excellent compatibility, dispersibility, and stability in a water-based epoxy resin matrix. The polyelectrolyte brushes significantly improve the structure of the coating matrix, and the spherical nanoparticles exhibit a shielding effect, reducing pores and extending the diffusion path for corrosive ions. Furthermore, the polyelectrolyte brushes have numerous, extended bristles, effectively enhancing the barrier properties of the coating, ultimately protecting metals from corrosion.

[0004] The present invention provides a high-efficiency anti-corrosion coating containing an electrolyte brush, which comprises, by mass fraction:

[0005] Polyelectrolyte brush: 0.01-1wt.%

[0006] Waterborne epoxy resin: 20-40wt.%

[0007] The curing agent: 15-30wt.%

[0008] The water content is: 30-55wt.%

[0009] According to the present invention, the polyelectrolyte brush is preferably prepared according to the following method: first, a photoinitiator is obtained by reacting HMP, MC, and pyridine, and then a polystyrene core is prepared by reacting sodium dodecanesulfonate, potassium persulfate, styrene monomer, and deionized water; the mass ratio of the surfactant, thermal initiator, and styrene monomer is preferably 1:50:3; the photoinitiator (HMEM) is dissolved in acetone, and the photoinitiator solvent is slowly dripped into the polystyrene core system under certain conditions. After the photoinitiator is completely dripped into the polystyrene core system, the system is stirred for 1-5 hours to obtain a polystyrene emulsion coated with a layer of photoinitiator; unreacted monomers, surfactants, and other impurities in the emulsion are removed by dialysis; the purified polystyrene emulsion and acrylic acid monomer are subjected to photopolymerization under ultraviolet irradiation for 0.3-1 hour, and then unreacted monomers and impurities are removed by ultrafiltration; finally, a polyelectrolyte brush with a polystyrene (PS) core and a polyacrylic acid (PAA) chain structure is obtained. The hydrodynamic particle size of the polyelectrolyte brush is preferably 100-200 nm, more preferably 140-160 nm; the molar ratio of styrene to acrylic acid is preferably 0.5:0.4 to 0.5:2, more preferably 1:1.

[0010] According to the present invention, after ultrasonically stirring a curing agent, water, and a polyelectrolyte brush for 7 minutes, a water-based epoxy resin is added and ultrasonication is continued for 5 minutes to obtain a polyelectrolyte composite water-based epoxy resin coating. The ultrasonic power used in the present invention is preferably in the range of 350-450W, more preferably 375-425W, and most preferably 400W; the ultrasonic time is preferably in the range of 3-10 minutes, more preferably 5-8 minutes, and most preferably 7 minutes; and the ultrasonic frequency is preferably 45 / 80 / 100kHz, more preferably 45 / 80kHz, and most preferably 45kHz.

[0011] According to the present invention, the epoxy resin is preferably one or more of E-51, E-20, E-12 and E-06; most preferably E-51; the curing agent is an amine curing agent, preferably one or more of United Curing Chemicals Banco901, United Curing Chemicals Banco916, Cardolite NX-8101, Shanghai Hanzhong Chemical H208B, and Shanghai Hanzhong Chemical H202B, most preferably United Curing Chemicals Banco901, and the mass ratio of the curing agent to the epoxy resin is preferably (0.8-1.2):1.3, and most preferably 1:1.3.

[0012] The present invention provides a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which can be prepared by the above method. As can be seen from the above technical solution, the beneficial effects of the present invention are: the high-efficiency anti-corrosion coating containing a polyelectrolyte brush proposed by the present invention uses water-based epoxy resin, curing agent and water as raw materials, and by adding a specific content of polyelectrolyte brush, the barrier effect of nanomaterials and the good compatibility and dispersibility of the polyelectrolyte brush in the epoxy resin matrix are utilized to improve the anti-corrosion performance of the coating. The water-based epoxy resin coating containing polyelectrolyte brushes has the advantages of good salt resistance, good anti-corrosion performance, good physical and mechanical properties, is green and environmentally friendly, and is suitable for various light anti-corrosion fields. In addition, the structure of the polyelectrolyte brush is highly designable, and the multifunctionality of the coating can be achieved by designing the structure of the polyelectrolyte brush or loading different functional additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the particle size distribution of the polyelectrolyte brush;

[0014] Figure 2 : DSC curves of Example 2 and pure water-based epoxy resin coating;

[0015] Figure 3 Nyquist and Bode spectra of the anti-corrosion performance test of the coatings in various embodiments (immersed in 3.5 wt.% NaCl solution for 1 day);

[0016] Figure 4Nyquist and Bode spectra of the anti-corrosion performance test of the coatings in various embodiments (immersed in 3.5 wt.% NaCl solution for 42 days);

[0017] Figure 5 : SEM images of corrosion products of the iron sheet coated with pure water-based epoxy resin and the iron sheet coated with the coating of Example 2 after immersion for 42 days. DETAILED DESCRIPTION

[0018] The following provides different embodiments or examples to further illustrate the technical means used in the present invention and the results achieved. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] The present invention provides a method for preparing a high-efficiency anticorrosive coating containing a polyelectrolyte brush, comprising the following steps: providing a polyelectrolyte brush; providing a water-based epoxy resin and a curing agent; and uniformly mixing and dispersing the polyelectrolyte brush solution, the water-based epoxy resin, the curing agent, and water to obtain a water-based epoxy resin coating containing the polyelectrolyte brush. The high-efficiency anticorrosive coating containing a polyelectrolyte brush and its preparation method are described in detail below.

[0020] Example 1: A polyelectrolyte brush composite waterborne epoxy resin high-efficiency anti-corrosion coating and its preparation method.

[0021] This embodiment provides a method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which specifically comprises the following steps:

[0022] Step 1: Prepare the photoinitiator. First, acetone and pyridine are distilled and purified, then 30g of HMP is dissolved in 150ml of acetone, stirred until dissolved, and 10ml of pyridine is added. The flask is then placed in an ice-water bath and stirred while being protected from light. 13.6g of MC is dissolved in 50ml of acetone, and then slowly added to the above reaction flask. After the MC is added, keep the ice bath and continue stirring for 30min, then remove the ice bath and continue stirring at room temperature for 12h. The organic solvent is then removed using a rotary evaporator (the temperature cannot be higher than 25°C) to obtain a yellow oily product. Finally, the yellow oily product is purified by silica gel chromatography to obtain HMEM.

[0023] Step 2: Prepare polyelectrolyte brushes. The PS core is prepared from surfactants, thermal initiators, styrene monomers and deionized water. Mix 0.16g of sodium dodecylsulfonate, 0.48g of potassium persulfate, 8.0g of styrene monomers and 200mL of deionized water, and remove oxygen from the system by circulating vacuum and nitrogen gas; turn on the mechanical stirring and control the stirring rate to 300rpm. After the emulsion is evenly mixed, slowly heat it to 80℃; after reacting for 2h, lower the reaction temperature to 70℃; at the same time, dissolve 7.2g of photoinitiator (HMEM) in acetone and slowly add it to the system at a drip rate of 6 seconds per drop; after the addition is complete, continue the reaction for 1h to obtain a PS emulsion with a layer of photoinitiator coated on the surface; remove impurities such as unreacted monomers in the emulsion by dialysis. The purified PS emulsion and acrylic acid monomer were photopolymerized under ultraviolet irradiation, and unreacted monomers and impurities were removed by ultrafiltration. Finally, a polyelectrolyte brush with a polystyrene (PS) core and polyacrylic acid (PAA) chain structure was obtained, and the solid content of the polyelectrolyte brush was 0.57 wt.%.

[0024] Step 3: Prepare a high-efficiency anticorrosion coating containing a polyelectrolyte brush. Combine 11.6g of curing agent 901 (60 wt.% solids content), 12.33g of deionized water, and 3.00g of a polyelectrolyte brush with ultrasonic stirring for 7 minutes to ensure uniform mixing. Then, add 9.2g of epoxy resin E51 and sonicate for 5 minutes. This yields a high-efficiency anticorrosion coating containing 0.05 wt.% of the polyelectrolyte brush.

[0025] Step 4: Apply the coating on the polished Q235 iron sheet, and after cross-linking and curing, a pure water-based epoxy resin coating can be obtained. The wet thickness of the coating is 100 μm and the dry thickness is about 38-42 μm.

[0026] Example 2: A polyelectrolyte brush composite waterborne epoxy resin high-efficiency anti-corrosion coating and its preparation method.

[0027] This embodiment provides a method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which specifically comprises the following steps:

[0028] Step 1: Prepare the photoinitiator. First, acetone and pyridine are distilled and purified, then 30g of HMP is dissolved in 150ml of acetone, stirred until dissolved, and 10ml of pyridine is added. Then, the flask is placed in an ice-water bath to keep stirring while protecting from light; 13.6g of MC is dissolved in 50ml of acetone, and then slowly added to the above reaction flask; after the MC is added dropwise, keep the ice bath and continue stirring for 30min, then remove the ice bath and continue stirring at room temperature for 12h; then use a rotary evaporator to remove the organic solvent (the temperature cannot be higher than 25°C) to obtain a yellow oily product, and finally purify the yellow oily product by silica gel chromatography to obtain HMEM.

[0029] Step 2: Prepare polyelectrolyte brushes. The PS core is prepared from surfactants, thermal initiators, styrene monomers and deionized water. Mix 0.16g of sodium dodecylsulfonate, 0.48g of potassium persulfate, 8.0g of styrene monomers and 200mL of deionized water, and remove oxygen from the system by circulating vacuum and nitrogen gas; turn on the mechanical stirring and control the stirring rate to 300rpm. After the emulsion is evenly mixed, slowly heat it to 80℃; after reacting for 2h, lower the reaction temperature to 70℃; at the same time, dissolve 7.2g of photoinitiator (HMEM) in acetone and slowly add it to the system at a drip rate of 6 seconds per drop; after the addition is complete, continue the reaction for 1h to obtain a PS emulsion with a layer of photoinitiator coated on the surface; remove impurities such as unreacted monomers in the emulsion by dialysis. The purified PS emulsion and acrylic acid monomer were photopolymerized under ultraviolet irradiation, and unreacted monomers and impurities were removed by ultrafiltration. Finally, a polyelectrolyte brush with a polystyrene (PS) core and polyacrylic acid (PAA) chain structure was obtained, and the solid content of the polyelectrolyte brush was 0.57 wt.%.

[0030] Step 3: Prepare a high-efficiency anticorrosion coating containing a polyelectrolyte brush. Combine 11.6g of curing agent 901 (60 wt.% solids content), 6.66g of deionized water, and 5.70g of a polyelectrolyte brush with ultrasonic stirring for 7 minutes to mix thoroughly. Then, add 9.2g of epoxy resin E51 and sonicate for 5 minutes. This yields a high-efficiency anticorrosion coating containing 0.10 wt.% of the polyelectrolyte brush.

[0031] Step 4: Apply the coating on the polished Q235 iron sheet, and after cross-linking and curing, a pure water-based epoxy resin coating can be obtained. The wet thickness of the coating is 100 μm and the dry thickness is about 38-42 μm.

[0032] Example 3: A polyelectrolyte brush composite waterborne epoxy resin high-efficiency anti-corrosion coating and its preparation method.

[0033] This embodiment provides a method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which specifically comprises the following steps:

[0034] Step 1: Prepare the photoinitiator. First, acetone and pyridine are distilled and purified, then 30g of HMP is dissolved in 150ml of acetone, stirred until dissolved, and 10ml of pyridine is added. Then, the flask is placed in an ice-water bath and stirred while being protected from light. 13.6g of MC is dissolved in 50ml of acetone, and then slowly added to the above reaction flask. After the addition of MC is completed, keep the ice bath and continue stirring for 30min, then remove the ice bath and continue stirring at room temperature for 12h. Then, use a rotary evaporator to remove the organic solvent (the temperature cannot be higher than 25°C) to obtain a yellow oily product. Finally, the yellow oily product is purified by silica gel chromatography to obtain HMEM.

[0035] Step 2: Prepare polyelectrolyte brushes. The PS core is prepared from surfactants, thermal initiators, styrene monomers and deionized water. Mix 0.16g of sodium dodecylsulfonate, 0.48g of potassium persulfate, 8.0g of styrene monomers and 200mL of deionized water, and remove oxygen from the system by circulating vacuum and nitrogen gas; turn on the mechanical stirring and control the stirring rate to 300rpm. After the emulsion is evenly mixed, slowly heat it to 80℃; after reacting for 2h, lower the reaction temperature to 70℃; at the same time, dissolve 7.2g of photoinitiator (HMEM) in acetone and slowly add it to the system at a drip rate of 6 seconds per drop; after the addition is complete, continue the reaction for 1h to obtain a PS emulsion with a layer of photoinitiator coated on the surface; remove impurities such as unreacted monomers in the emulsion by dialysis. The purified PS emulsion and acrylic acid monomer were photopolymerized under ultraviolet irradiation, and unreacted monomers and impurities were removed by ultrafiltration. Finally, a polyelectrolyte brush with a polystyrene (PS) core and polyacrylic acid (PAA) chain structure was obtained, and the solid content of the polyelectrolyte brush was 0.57 wt.%.

[0036] Step 3: Prepare a high-efficiency anticorrosion coating containing a polyelectrolyte brush. 11.6g of curing agent 901 (60 wt.% solids content), 3.39g of deionized water, and 8.99g of a polyelectrolyte brush were mixed by ultrasonic stirring for 7 minutes to achieve uniformity. Then, 9.2g of epoxy resin E51 was added and ultrasonicated for 5 minutes. This resulted in a high-efficiency anticorrosion coating containing 0.15 wt.% of the polyelectrolyte brush.

[0037] Step 4: Apply the coating on the polished Q235 iron sheet, and after cross-linking and curing, a pure water-based epoxy resin coating can be obtained. The wet thickness of the coating is 100 μm and the dry thickness is about 38-42 μm.

[0038] Example 4: A polyelectrolyte brush composite waterborne epoxy resin high-efficiency anti-corrosion coating and its preparation method.

[0039] This embodiment provides a method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which specifically comprises the following steps:

[0040] Step 1: Prepare the photoinitiator. First, acetone and pyridine are distilled and purified, then 30g of HMP is dissolved in 150ml of acetone, stirred until dissolved, and 10ml of pyridine is added. Then, the flask is placed in an ice-water bath and stirred while being protected from light. 13.6g of MC is dissolved in 50ml of acetone, and then slowly added to the above reaction flask. After the addition of MC is completed, keep stirring in the ice bath for 30min, then remove the ice bath and continue stirring at room temperature for 12h. Then, use a rotary evaporator to remove the organic solvent (the temperature cannot be higher than 25°C) to obtain a yellow oily product. Finally, the yellow oily product is purified by silica gel chromatography to obtain HMEM.

[0041] Step 2: Prepare polyelectrolyte brushes. The PS core is prepared from surfactants, thermal initiators, styrene monomers and deionized water. Mix 0.16g of sodium dodecylsulfonate, 0.48g of potassium persulfate, 8.0g of styrene monomers and 200mL of deionized water, and remove oxygen from the system by circulating vacuum and nitrogen gas; turn on the mechanical stirring and control the stirring rate to 300rpm. After the emulsion is evenly mixed, slowly heat it to 80℃; after reacting for 2h, lower the reaction temperature to 70℃; at the same time, dissolve 7.2g of photoinitiator (HMEM) in acetone and slowly add it to the system at a drip rate of 6 seconds per drop; after the addition is complete, continue the reaction for 1h to obtain a PS emulsion with a layer of photoinitiator coated on the surface; remove impurities such as unreacted monomers in the emulsion by dialysis. The purified PS emulsion and acrylic acid monomer were photopolymerized under ultraviolet irradiation, and unreacted monomers and impurities were removed by ultrafiltration. Finally, a polyelectrolyte brush with a polystyrene (PS) core and polyacrylic acid (PAA) chain structure was obtained, and the solid content of the polyelectrolyte brush was 0.57 wt.%.

[0042] Step 3: Prepare a high-efficiency anticorrosion coating containing a polyelectrolyte brush. 11.6g of curing agent 901 (60 wt.% solids content), 0.4g of deionized water, and 11.98g of a polyelectrolyte brush were mixed by ultrasonic stirring for 7 minutes to achieve uniformity. Then, 9.2g of epoxy resin E51 was added and ultrasonicated for 5 minutes. This resulted in a high-efficiency anticorrosion coating containing 0.20 wt.% of the polyelectrolyte brush.

[0043] Step 4: Apply the coating on the polished Q235 iron sheet, and after cross-linking and curing, a pure water-based epoxy resin coating can be obtained. The wet thickness of the coating is 100 μm and the dry thickness is about 38-42 μm.

[0044] Example 5: A polyelectrolyte brush composite waterborne epoxy resin high-efficiency anti-corrosion coating and its preparation method.

[0045] This embodiment provides a method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush, which specifically comprises the following steps:

[0046] Step 1: Prepare the photoinitiator. First, acetone and pyridine are distilled and purified, then 30g of HMP is dissolved in 150ml of acetone, stirred until dissolved, and 10mL of pyridine is added. Then, the flask is placed in an ice-water bath and stirred while being protected from light. 13.6g of MC is dissolved in 50mL of acetone, and then slowly added to the above reaction flask. After the addition of MC is completed, keep the ice bath and continue stirring for 30min, then remove the ice bath and continue stirring at room temperature for 12h. Then, use a rotary evaporator to remove the organic solvent (the temperature cannot be higher than 25°C) to obtain a yellow oily product. Finally, the yellow oily product is purified by silica gel chromatography to obtain HMEM.

[0047] Step 2: Prepare polyelectrolyte brushes. The PS core is prepared from surfactants, thermal initiators, styrene monomers and deionized water. Mix 0.16g of sodium dodecylsulfonate, 0.48g of potassium persulfate, 8.0g of styrene monomers and 200mL of deionized water, and remove oxygen from the system by circulating vacuum and nitrogen gas; turn on the mechanical stirring and control the stirring rate to 300rpm. After the emulsion is evenly mixed, slowly heat it to 80℃; after reacting for 2h, lower the reaction temperature to 70℃; at the same time, dissolve 7.2g of photoinitiator (HMEM) in acetone and slowly add it to the system at a drip rate of 6 seconds per drop; after the addition is complete, continue the reaction for 1h to obtain a PS emulsion with a layer of photoinitiator coated on the surface; remove impurities such as unreacted monomers in the emulsion by dialysis. The purified PS emulsion and acrylic acid monomer were photopolymerized under ultraviolet irradiation, and unreacted monomers and impurities were removed by ultrafiltration. Finally, a polyelectrolyte brush with a polystyrene (PS) core and polyacrylic acid (PAA) chain structure was obtained, and the solid content of the polyelectrolyte brush was 0.57 wt.%.

[0048] Step 3: Prepare a high-efficiency anticorrosion coating containing a polyelectrolyte brush. 11.6g of curing agent 901 (60 wt.% solids content) and 14.98g of a polyelectrolyte brush were ultrasonically stirred for 7 minutes to mix thoroughly. Then, 9.2g of epoxy resin E51 was added and ultrasonicated for 5 minutes. This resulted in a high-efficiency anticorrosion coating containing 0.25 wt.% of the polyelectrolyte brush.

[0049] Step 4: Apply the coating on the polished Q235 iron sheet, and after cross-linking and curing, a pure water-based epoxy resin coating can be obtained. The wet thickness of the coating is 100 μm and the dry thickness is about 38-42 μm.

[0050] The polyelectrolyte brushes obtained in Examples 1-5 and the high-efficiency anticorrosive coatings containing the polyelectrolyte brushes were subjected to the following tests:

[0051] Dynamic Light Scattering (DLS): Dynamic light scattering technology is used to determine the hydrodynamic particle size and particle size dispersion of nanoparticles.

[0052] Differential Scanning Calorimetry (DSC): The glass transition temperatures (T g ).

[0053] Electrochemical testing: The cross-linked and cured coating was immersed in a 3.5 wt.% NaCl solution for 42 days. The electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PD) tests of Examples 1-5 were performed using an electrochemical workstation. The EIS test was performed at a stable open circuit potential (OCP), with an amplitude of 10 mV and a frequency range of 10 5 -10 -2 Potentiodynamic polarization (PD) tests were performed on the coatings after immersion in 3.5 wt.% NaCl solution for 42 days, with a range of OCP ± 300 mV and a scan rate of 10 mV / s.

[0054] Scanning electron microscopy (SEM): After soaking the iron sheet coated with pure water-based epoxy resin and the iron sheet coated with the coating of Example 2 for 42 days, the coating was removed, and the corrosion products were studied using a scanning electron microscope. The elemental composition of the corrosion products was analyzed using the energy dispersive spectrometer built into the scanning electron microscope.

[0055] The test results are shown in Table 1 and Figure 1-5 .

[0056] Table 1: Potentiokinetic polarization test data

[0057]

[0058] From the test results of dynamic light scattering ( Figure 1 ) It can be seen that the hydrodynamic particle size of the polyelectrolyte brushes synthesized by this method is uniform, which helps to form a more uniform coating with lower porosity. Figure 2It can be seen that the glass transition temperature of the coating with the addition of polyelectrolyte brushes increases. This is because the carboxyl groups of the polyacrylic acid in the bristles of the polyelectrolyte brushes will react with the water-based epoxy resin under the promotion of the amine curing agent, thereby increasing the crosslinking density of the water-based epoxy resin. From the EIS test results, it can be seen that the Nyquist arc radius and low-frequency impedance modulus of the examples with polyelectrolyte brushes in the formula are much higher than those of the water-based epoxy resin coating formula; with the increase in the amount of polyelectrolyte brush added, the low-frequency impedance modulus first increases and then tends to stabilize, and is 1-2 orders of magnitude higher than that of the pure water-based epoxy coating; from the PD test results (Table 1), it can be seen that the corrosion current and corrosion rate of the coating with the addition of polyelectrolyte brushes have been significantly reduced; and by Figure 5 Observations revealed that after 42 days of immersion, the iron sheet coated with the polyelectrolyte brush exhibited significantly fewer corrosion products and no higher-order forms of corrosion products compared to the iron sheet coated with the waterborne epoxy resin. In summary, the coating's anti-corrosion performance was significantly improved.

[0059] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A high-efficiency anti-corrosion coating containing a polyelectrolyte brush, characterized in that: Includes the following components by mass percentage: Polyelectrolyte brush 0.01-1 wt% Waterborne epoxy resin 20-40 wt% Curing agent 15-30 wt% Water 30-55 wt% The preparation method of the polyelectrolyte brush comprises the following steps: The polystyrene core is first prepared by reacting a surfactant, a thermal initiator, a styrene monomer, and deionized water, wherein the mass ratio of the surfactant, the thermal initiator, and the styrene monomer is 1:3:50; Then, the photoinitiator is dissolved in acetone to prepare a photoinitiator solvent, which is slowly dripped into the polystyrene core system; after the photoinitiator solvent is dripped into the polystyrene core system, stirring is continued for 1-5 hours to obtain a polystyrene emulsion with a layer of photoinitiator coated on the surface; Finally, the polystyrene emulsion and acrylic monomer were photopolymerized under ultraviolet irradiation for 0.3-1 h; The preparation method of the photoinitiator comprises the following steps: adding 2-hydroxy-4'-hydroxyethoxy-2-methylphenyl ethyl ketone and pyridine into acetone, then dripping methacryloyl chloride, stirring, rotary evaporation and purification.

2. The high-efficiency anti-corrosion coating containing a polyelectrolyte brush according to claim 1, characterized in that: The hydrodynamic particle size of the polyelectrolyte brushes is 100-200 nm.

3. The method for preparing a high-efficiency anti-corrosion coating containing a polyelectrolyte brush according to any one of claims 1-2, characterized in that: Specifically include the following steps: S1. preparing a photoinitiator; S2, preparation of spherical polyelectrolyte brushes by photoemulsion polymerization; S3. Evenly mix the polyelectrolyte brush, water-based epoxy resin, curing agent and water.

4. The method for preparing a high-efficiency anticorrosive coating containing a polyelectrolyte brush according to claim 3, characterized in that: The mass ratio of curing agent to water-based epoxy resin is (0.8-1.2):1.3.

Images