A steel structure graphene anticorrosive coating suitable for marine corrosion environment and a preparation method thereof

Abstract

The application discloses a kind of steel structure graphene anticorrosive coating suitable for marine corrosive environment and preparation method, anticorrosive coating, raw material includes the following components according to mass fraction: graphene oxide 10~20 parts, epoxy resin 100~200 parts, dispersing agent 50~100 parts, nanometer material 5~10 parts, surfactant 30~50 parts, ethylene-vinyl acetate copolymer 30~50 parts, succinic acid 20~50 parts, butanediol 30~75 parts, ethyl silicate 10~20 parts, sodium methylsilanol 500~600 parts, catalyst 3~5 parts, tyrosine 10~20 parts.The steel structure graphene anticorrosive coating provided by the application is combined closely with steel structure, has strong anti-aging ability, is not easy to peel, can resist marine environment corrosion, has low cost, stable properties, and reduces the influence on surrounding environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of civil engineering, and relates to a graphene anticorrosive coating for steel structures suitable for marine corrosive environments and a preparation method. BACKGROUND

[0002] In recent years, with the continuous development of China's economy and the implementation of the marine strategy, a large number of island construction, cross-sea bridges, port development, marine pipe corridors and other major national projects are accelerating. However, due to the existence of various erosion media in the harsh marine environment, durability problems such as rusting, chloride ion erosion and sulfate corrosion of steel structures occur. These problems have been prevalent in infrastructure projects in China's marine environment for many years and have shown a trend of increasing year by year, which greatly threatens the overall performance of steel structures in the marine environment. Therefore, anticorrosive coatings are needed to isolate water vapor, chloride ions, sulfates and other substances in the marine environment to avoid overall instability problems caused by corrosion of steel structures.

[0003] Existing steel structure protection mostly uses epoxy resin as an anticorrosive coating layer, but there are inevitably some pores in the epoxy resin, which are easily eroded by ions such as chloride ions and sulfate ions in the marine atmosphere with high concentration and large diffusion coefficient. In addition, the molecular weight of epoxy resin is large, and the hardness after curing is high, which is prone to stress concentration. Furthermore, there are many small molecules and unstable compounds such as free amines and epoxy groups in epoxy resin, which are prone to oxidation, electron loss and other reactions under the action of acid and ultraviolet light, and age quickly, which easily causes the coating to peel off. The patent with publication number CN107353773A discloses a water-based epoxy anticorrosive coating containing graphene, its preparation method and application. The graphene oxide and silicon dioxide do not chemically react with the epoxy resin, but are physically distributed in the epoxy resin. The structure of the prepared coating is unstable, is prone to aging and has poor durability.

[0004] Therefore, it is urgent to seek a new anticorrosive coating for steel structures that is resistant to aging, not prone to peeling and suitable for marine corrosive environments. SUMMARY

[0005] To solve the above problems, the application provides a graphene anticorrosive coating for steel structures suitable for marine corrosive environments, which is closely combined with the steel structure, has strong anti-aging ability, is not prone to peeling, can resist marine environmental corrosion, has low cost, stable properties, reduces the impact on the surrounding environment and solves the problems in the prior art.

[0006] Another object of the application is to provide a preparation method of the graphene anticorrosive coating for steel structures suitable for marine corrosive environments.

[0007] The technical scheme adopted by the present application is a kind of steel structure graphene anticorrosive coating suitable for marine corrosive environment, raw materials include the following components according to mass fraction: graphene oxide 10-20 parts, epoxy resin 100-200 parts, dispersing agent 50-100 parts, nano material 5-10 parts, surface active agent 30-50 parts, ethylene-vinyl acetate copolymer 30-50 parts, succinic acid 20-50 parts, butanediol 30-75 parts, tetraethyl orthosilicate 10-20 parts, sodium methylsilanol 500-600 parts, catalyst 3-5 parts, tyrosine 10-20 parts.

[0008] Further, the dispersing agent is alcohol, ethylene glycol or ethylenediaminetetraacetic acid.

[0009] Further, the nano material is nano Al2O3, nano SiO2 or nano CaO.

[0010] Further, the surface active agent is one or more of ammonium salt, quaternary ammonium salt, alcohol ether strong acid salt.

[0011] Further, the catalyst is one or more of ethylene glycol antimony or titanium alcoholate.

[0012] A kind of steel structure graphene anticorrosive coating suitable for marine corrosive environment preparation method, including the following steps:

[0013] Step S1, according to the following mass fraction, each raw material is taken: graphene oxide 10-20 parts, epoxy resin 100-200 parts, dispersing agent 50-100 parts, nano material 5-10 parts, surface active agent 30-50 parts, ethylene-vinyl acetate copolymer 30-50 parts, succinic acid 20-50 parts, butanediol 30-75 parts, tetraethyl orthosilicate 10-20 parts, sodium methylsilanol 500-600 parts, catalyst 3-5 parts, tyrosine 10-20 parts.

[0014] Step S2, at room temperature (20-25 DEG C), succinic acid and butanediol are sequentially placed in the reaction kettle, magnet is added, and the magnet rotating speed is adjusted to 500-800 r / min, mechanical stirring is carried out for 0.5-1 h, so that it is fully mixed, and then oil bath is carried out at 110-120 DEG C for 1-2 h to activate it;

[0015] Step S3, catalyst is added to the activated mixture, the magnet rotating speed is adjusted to 400-600 r / min, the oil bath temperature is adjusted to 230-250 DEG C, succinic acid and butanediol occur polycondensation reaction and esterification reaction, after mechanical stirring for 5-6 h, the temperature is lowered to 50-60 DEG C, and activated polybutylene succinate is obtained;The catalyst mainly promotes the polycondensation reaction and esterification reaction of succinic acid and butanediol to generate polybutylene succinate;

[0016] Step S4, the weighed ethylene-vinyl acetate copolymer and tetraethyl orthosilicate are poured into a reaction kettle, heated to 200-250℃, and mechanically stirred at 1000-1500 r / min for 4-5 h, then cooled to 30-40℃, and mechanically stirred at 300-500 r / min for 6-8 h;

[0017] Step S5, the graphene oxide, nanomaterials, and dispersing agent are sequentially added into the reaction kettle, the magnet speed is adjusted to 800-1000 r / min at 130-140℃, mechanically stirred for 0.5-1 h, then the surface activator is added, heated to 170-180℃, mechanically stirred for 1.5-2 h, then the tyrosine is added, cooled to 80-100℃, and the reaction is completed after 6-8 h, and then cooled to room temperature; the mass ratio of the total mass of graphene oxide and nanomaterials to the mass of the surfactant is 0.8-1:1; the dispersing agent uniformly disperses the graphene oxide, nanomaterials, etc. in the epoxy resin; the surfactant mainly activates the graphene oxide, nanomaterials, etc. to enhance the active sites in the graphene oxide, nanomaterials, etc., and then promotes the formation of a high-strength network structure film with sodium methylsilanol, ethylene-vinyl acetate copolymer, and polybutylene succinate;

[0018] Step S6, the epoxy resin and sodium methylsilanol are sequentially added into the reaction kettle, the magnet speed is adjusted to 1500-2000 r / min at 20-25℃, and high-speed stirring is performed for 3-4 h to obtain a graphene corrosion-resistant coating for steel structures suitable for marine corrosion environments; the nanomaterials are rich in metal cations, which can be ionized into metal cations in the solution, and then promote the displacement reaction of the metal cations with sodium methylsilanol to form more stable methylsilanol-based high molecular compounds.

[0019] Further, in step S2, the molar ratio of succinic acid to butanediol is 1:1.5-3.

[0020] Further, in step S3, the catalyst is used in an amount of 0.05-0.2 of the total mass of succinic acid and butanediol.

[0021] Further, in step S4, the ratio of ethylene-vinyl acetate copolymer to tetraethyl orthosilicate is 2-3:1; the tetraethyl orthosilicate mainly links the ethylene-vinyl acetate copolymer and the activated polybutylene succinate to form a high-molecular protective film that can isolate water vapor and chloride ions, and modifies the sodium methylsilanol in the subsequent reaction (new chemical bonds are formed between sodium methylsilanol, ethylene-vinyl acetate copolymer, and polybutylene succinate, thus causing a polymerization reaction) to make the viscosity of sodium methylsilanol larger and promote the adhesion of sodium methylsilanol to the surface layer of the steel structure.

[0022] Further, in the step S5, the mass ratio of tyrosine to ethylene-vinyl acetate copolymer is 0.3-0.4, the mass ratio of graphene oxide, nanomaterial and dispersant is 1:0.5:5, and further consumption of ethylene-vinyl acetate copolymer and succinic acid and butanediol makes them fully react and react with nanomaterial to ionize more cations.

[0023] The beneficial effects of the present application are:

[0024] 1. Compared with the traditional paint, the graphene and nanomaterial are uniformly distributed in the anticorrosive paint, which reduces the porosity of the protective paint, improves the structural density, effectively prevents the diffusion of corrosive medium in the paint, and enhances the internal bonding force and toughness of the paint, and has significant improvement in corrosion resistance, immersion resistance, bonding force and other properties compared with the traditional paint.

[0025] 2. The present application utilizes the carbonization reaction and displacement reaction of sodium methylsilanol with cations to generate a high molecular film with more stable structure, which avoids the electrochemical reaction of steel structure and significantly improves the stability of the anticorrosive paint.

[0026] 3. The present application utilizes the reaction of tetraethyl orthosilicate, ethylene-vinyl acetate copolymer, polybutylene succinate and sodium methylsilanol to generate a high molecular material with large molecules and stable structure, which occurs polycondensation reaction with epoxy resin to generate a high-strength network structure film, overcoming the problems of unstable molecular structure, easy aging and many pores of traditional epoxy-based paint. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is the SEM image of graphene anticorrosive paint generated by example 1.

[0029] Figure 2 is the SEM image of graphene anticorrosive paint generated by example 2.

[0030] Figure 3 is the SEM image of graphene anticorrosive paint generated by example 3.

[0031] Figure 4 is the SEM image of graphene anticorrosive paint generated by example 4.

[0032] Figure 5 is the SEM image of graphene anticorrosive paint generated by example 5.

[0033] Figure 6 is an SEM image of an epoxy coating.

[0034] Figure 7 is an SEM image of a polyurethane coating. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] Embodiment 1,

[0037] A steel structure graphene anticorrosive coating suitable for marine corrosive environment and a preparation method thereof, comprising the following steps:

[0038] Step S1, the following mass parts of each raw material are taken: 10 parts of graphene oxide, 100 parts of epoxy resin, 50 parts of alcohol, 5 parts of nano-Al2O3, 30 parts of ammonium salt, 30 parts of ethylene-vinyl acetate copolymer, 20 parts of succinic acid, 30 parts of butanediol, 10 parts of tetraethyl orthosilicate, 500 parts of sodium methylsilanol, 3 parts of ethylene glycol antimony, and 10 parts of tyrosine.

[0039] Step S2, at 20℃, succinic acid and butanediol with a molar ratio of 1:3 are sequentially put into a reaction kettle, a magnet is added, and the rotating speed of the magnet is adjusted to 500r / min, mechanical stirring is performed for 0.5h, and then the mixture is activated by oil bath at 110℃ for 1h.

[0040] Step S3, ethylene glycol antimony with a total amount of 0.1 of succinic acid and butanediol is added to the activated mixture, the rotating speed of the magnet is adjusted to 400r / min, the oil bath temperature is adjusted to 230℃, and the succinic acid and butanediol undergo polycondensation and esterification reactions, and then the mixture is mechanically stirred at 5-6h, and then the temperature is lowered to 50℃, and the activated polybutylene succinate is obtained.

[0041] Step S4, the weighed ethylene-vinyl acetate copolymer and tetraethyl orthosilicate are poured into the reaction kettle, heated to 200℃, and then mechanically stirred at 1000r / min by using the magnet for 4h, and then the temperature is lowered to 30℃, and then mechanically stirred at 300r / min for 6h.

[0042] Step S5, graphene oxide, nano-Al2O3, alcohol are added into the reaction kettle in turn, at 130℃, the magnet speed is adjusted to 800r / min, mechanical stirring for 0.5h, then ammonium salt is added, the temperature is raised to 170℃, mechanical stirring for 1.5h, then tyrosine is added, the temperature is lowered to 80℃, the reaction is completed after 6h, and then it is cooled to room temperature.

[0043] Step S6, epoxy resin, sodium methylsilanol are added into the reaction kettle in turn, at 25℃, the magnet speed is adjusted to 1500r / min, high-speed stirring for 3h, then the graphene corrosion-resistant coating for steel structure suitable for marine environment is obtained.

[0044] S4 is to make tetraethyl orthosilicate, ethylene-vinyl acetate copolymer and activated polybutylene succinate initially polymerize to form a certain amount of high molecular compound; S5 is to activate graphene oxide and nanomaterials by surfactant, further accelerate the reaction of tetraethyl orthosilicate, ethylene-vinyl acetate copolymer, graphene oxide, nanomaterials and activated polybutylene succinate, and further consume ethylene-vinyl acetate copolymer and succinic acid and butanediol, so that they completely react. S6 is to modify sodium methylsilanol with the generated high molecular material in S5, so that its viscosity is larger, and it is more easily adhered to the surface layer of steel structure, and after the steel is protected by the graphene corrosion-resistant coating, it can occur carbonization reaction with CO2 in the marine environment, and displacement reaction with cations in seawater and cations in nanomaterials, to generate a high molecular film with more stable structure, thereby achieving the protection of steel in marine environment.

[0045] Example 2:

[0046] A graphene corrosion-resistant coating for steel structure suitable for marine environment and a preparation method thereof, comprising the following steps:

[0047] Step S1, the following mass fractions of raw materials are weighed: graphene oxide 20 parts, epoxy resin 200 parts, ethylene glycol 100 parts, nano-CaO 10 parts, alcohol ether strong acid salt 50 parts, ethylene-vinyl acetate copolymer 50 parts, succinic acid 50 parts, butanediol 75 parts, tetraethyl orthosilicate 20 parts, sodium methylsilanol 600 parts, antimony ethylene glycol 5 parts, and tyrosine 20 parts.

[0048] Step S2, at 25℃, succinic acid and butanediol with a molar ratio of 1:1.5 are added into the reaction kettle in turn, a magnet is added, and the magnet speed is adjusted to 800r / min, mechanical stirring for 1h, so that they are fully mixed, and then they are activated by oil bath at 120℃ for 2h.

[0049] Step S3, to the activated mixture, add titanium alkoxide of 0.2 times the total mass of succinic acid and butanediol, and adjust the speed of the magnet to 600 r / min, the oil bath temperature to 250℃, mechanical stirring for 6h, then cool to 60℃, and get activated polybutylene succinate.

[0050] Step S4, weigh the ethylene-vinyl acetate copolymer, tetraethyl orthosilicate, and pour them into the reaction kettle, heat to 250℃, and mechanically stir at 1500 r / min for 5h, then cool to 40℃, and mechanically stir at 500 r / min for 8h.

[0051] Step S5, add graphene oxide, nano-CaO, and ethylene glycol into the reaction kettle in turn, adjust the speed of the magnet to 1000 r / min at 140℃, mechanically stir for 1h, then add alcohol ether strong acid salt, heat to 180℃, mechanically stir for 2h, then add tyrosine, cool to 100℃, and end the reaction after 8h, and cool to room temperature.

[0052] Step S6, add epoxy resin and sodium methylsilanol into the reaction kettle in turn, adjust the speed of the magnet to 2000 r / min at 20℃, and high-speed stir for 4h, then get the steel structure graphene corrosion-resistant coating suitable for marine corrosion environment.

[0053] Example 3:

[0054] A steel structure graphene corrosion-resistant coating suitable for marine corrosion environment and a preparation method thereof, comprising the following steps:

[0055] Step S1, according to the following mass fraction, weigh each raw material: graphene oxide 15 parts, epoxy resin 150 parts, alcohol 80 parts, nano-Al2O3 8 parts, ammonium salt 40 parts, ethylene-vinyl acetate copolymer 40 parts, succinic acid 35 parts, butanediol 55 parts, tetraethyl orthosilicate 15 parts, sodium methylsilanol 550 parts, ethylene glycol antimony 4 parts, and tyrosine 15 parts.

[0056] Step S2, at 25℃, put succinic acid and butanediol with a molar ratio of 1:2.5 into the reaction kettle in turn, add a magnet, and adjust the speed of the magnet to 700 r / min, mechanically stir for 0.8h, mix thoroughly, and activate at an oil bath temperature of 115℃ for 1.5h.

[0057] Step S3, to the activated mixture, add ethylene glycol antimony of 0.1 times the total mass of succinic acid and butanediol, and adjust the speed of the magnet to 500 r / min, the oil bath temperature to 235℃, mechanically stir for 5.5h, then cool to 55℃, and get activated polybutylene succinate.

[0058] Step S4, the weighed ethylene-vinyl acetate copolymer, tetraethyl orthosilicate is poured into the reaction kettle, heated to 225℃, and mechanically stirred at 1300r / min speed for 4.5h, then the surfactant is added, and the temperature is lowered to 35℃, and mechanically stirred at 400r / min speed for 7h.

[0059] Step S5, the graphene oxide, nano-Al2O3, alcohol are added into the reaction kettle in turn, the magnet speed is adjusted to 900r / min at 135℃, and mechanically stirred for 0.7h, then the ammonium salt is added, the temperature is raised to 175℃, and mechanically stirred for 1.5h, then the tyrosine is added, the temperature is lowered to 90℃, and the reaction is completed after 7h, and then it is cooled to room temperature.

[0060] Step S6, the epoxy resin, sodium methylsilanol are added into the reaction kettle in turn, the magnet speed is adjusted to 1800r / min at 25℃, and high-speed stirring is carried out for 3.5h to obtain a graphene anticorrosive coating suitable for steel structure in marine corrosive environment.

[0061] Example 4:

[0062] A graphene anticorrosive coating suitable for steel structure in marine corrosive environment and a preparation method thereof, comprising the following steps:

[0063] Step S1, the following mass fractions of raw materials are weighed: graphene oxide 15 parts, epoxy resin 150 parts, ethylenediaminetetraacetic acid 80 parts, nano-SiO2 8 parts, quaternary ammonium salt 40 parts, ethylene-vinyl acetate copolymer 40 parts, succinic acid 35 parts, butanediol 55 parts, tetraethyl orthosilicate 20 parts, sodium methylsilanol 550 parts, ethylene glycol antimony 4 parts, and tyrosine 15 parts.

[0064] Step S2, at room temperature 25℃, the succinic acid and butanediol with a molar ratio of 1:2.5 are added into the reaction kettle in turn, a magnet is added, and the magnet speed is adjusted to 700r / min, and mechanically stirred for 0.8h to make them fully mixed, and then activated by oil bath at 135℃ for 1.5h.

[0065] Step S3, 0.05 of ethylene glycol antimony of the total amount of succinic acid and butanediol is added to the activated mixture, the magnet speed is adjusted to 500r / min, the oil bath temperature is adjusted to 235℃, and mechanically stirred for 5.5h, and then cooled to 55℃ to obtain activated polybutylene succinate.

[0066] Step S4, the weighed ethylene-vinyl acetate copolymer, tetraethyl orthosilicate is poured into the reaction kettle, heated to 225℃, and mechanically stirred at 1300r / min speed for 4.5h, then the surfactant is added, and the temperature is lowered to 35℃, and mechanically stirred at 400r / min speed for 7h.

[0067] Step S5, graphene oxide, nano-SiO2, ethylenediaminetetraacetic acid solution were added into the reaction kettle in turn, the magnet speed was adjusted to 900r / min at 135℃, mechanical stirring was carried out for 0.7h, then quaternary ammonium salt was added, the temperature was increased to 175℃, mechanical stirring was carried out for 1.5h, then tyrosine was added, the temperature was decreased to 90℃, and the reaction was completed after 7h, and then it was cooled to room temperature.

[0068] Step S6, epoxy resin and sodium methylsilanol were added into the reaction kettle in turn at room temperature 25℃, the magnet speed was adjusted to 1800r / min, high-speed stirring was carried out for 3.5h, and then the graphene corrosion-resistant coating for steel structure suitable for marine corrosion environment was obtained.

[0069] Example 5:

[0070] A graphene corrosion-resistant coating for steel structure suitable for marine corrosion environment and a preparation method thereof, comprising the following steps:

[0071] Step S1, the following mass fractions of raw materials were taken: graphene oxide 10 parts, epoxy resin 300 parts, dispersing agent 120 parts, nano-material 20 parts, ammonium salt 30 parts, ethylene-vinyl acetate copolymer 60 parts, succinic acid 20 parts, butanediol 90 parts, tetraethyl orthosilicate 20 parts, sodium methylsilanol 800 parts, catalyst 3 parts, and tyrosine 5 parts.

[0072] Step S2, succinic acid and butanediol with a molar ratio of 1:3 were put into the reaction kettle in turn at room temperature 20℃, a magnet was added, and the magnet speed was adjusted to 500r / min, mechanical stirring was carried out for 0.5h, and then it was activated by oil bath at 110℃ for 1-2h.

[0073] Step S3, 0.1 of ethylene glycol antimony was added to the activated mixture, the magnet speed was adjusted to 400r / min, the oil bath temperature was adjusted to 175℃, succinic acid and butanediol underwent polycondensation and esterification reactions, mechanical stirring was carried out for 5-6h, and then the temperature was decreased to 50℃.

[0074] Step S4, the weighed ethylene-vinyl acetate copolymer and tetraethyl orthosilicate were poured into the reaction kettle, heated to 200℃, and then mechanically stirred at 1000r / min by using a magnet for 4h, and then the temperature was decreased to 30℃, and mechanical stirring was carried out at 300r / min for 6h.

[0075] Step S5, graphene oxide, nano-Al2O3 and alcohol are sequentially added into the reaction kettle, the rotation speed of the magnet is adjusted to 800 r / min at 130℃, mechanical stirring is carried out for 0.5 h, then ammonium salt is added, the temperature is increased to 350℃, mechanical stirring is carried out for 1.5 h, then tyrosine is added, the temperature is decreased to 80℃, and the reaction is completed after 6 h, and then the reaction is cooled to room temperature.

[0076] Step S6, epoxy resin and sodium methylsilanol are sequentially added into the reaction kettle, the rotation speed of the magnet is adjusted to 1500 r / min at room temperature 25℃, high-speed stirring is carried out for 3 h, and then the graphene corrosion-resistant coating suitable for marine corrosion environment is obtained.

[0077] The performance comparison effect of the corrosion-resistant coatings prepared by Examples 1-5 and the existing epoxy resin coatings and polyurethane coatings is shown in Table 1.

[0078] Table 1 Performance comparison effect of the corrosion-resistant coatings prepared by Examples 1-4 and the existing coatings

[0079]

[0080]

[0081] The main component of the epoxy coating in Table 1 is epoxy resin, and the main component of the polyurethane coating is polyurethane. As can be seen from Table 1, the steel structure corrosion-resistant coating prepared by Examples 1-4 has excellent corrosion resistance, and no defects such as discoloration, blistering, cracking, peeling, rusting and adhesion reduction are found during the test. The steel structure corrosion-resistant coating prepared by Example 5 has incomplete reaction of raw materials due to the reaction temperature exceeding the specified range, has larger internal pores, and has decreased adhesion, so the corrosion resistance of the prepared steel structure corrosion-resistant coating is decreased, and a small amount of defects such as blistering, cracking, peeling and rusting are found on the surface during the test. The microstructure of the steel structure corrosion-resistant coating prepared by the preparation method of Examples 1-5 of the present application is shown in Figure 1, and the pores are small, and the graphene and nano materials are uniformly distributed in the corrosion-resistant coating, which enhances the internal bonding force and toughness of the coating, and the corrosion resistance, immersion resistance and adhesion of the steel structure corrosion-resistant coating prepared by the preparation method of Examples 1-5 of the present application are significantly improved compared with the traditional coating. Figures 1-5 Figures 6-7

[0082] In the examples of the present application, the molar ratio of succinic acid and butanediol is 1:1.5-3, which is mainly to generate activated polybutylene succinate. If the amount of polybutylene succinate generated exceeds this range, it is insufficient to react with tetraethyl orthosilicate, ethylene-vinyl acetate copolymer and sodium methylsilanol, which will affect the generation of subsequent chemical bonds, and the performance of the generated graphene corrosion-resistant coating will be poor, and the reaction of succinic acid and butanediol will not be complete, and the excess succinic acid and butanediol will be free in the graphene corrosion-resistant coating, which will increase the porosity of the graphene corrosion-resistant coating and reduce the adhesion. ​​

[0083] In the embodiment of the present application, the catalyst is used in an amount of 0.05-0.2 of the total mass of succinic acid and butanediol, so as to promote the reaction of succinic acid and butanediol to generate polybutylene succinate faster. If the amount of catalyst exceeds the range, the catalyst cannot play a catalytic role, or the reaction of succinic acid and butanediol is incomplete.

[0084] In the embodiment of the present application, the ratio of ethylene-vinyl acetate copolymer to tetraethyl orthosilicate is 2-3:1. The reaction sites in the tetraethyl orthosilicate are used to link ethylene-vinyl acetate copolymer and polybutylene succinate, so as to generate a high molecular material with a larger molecular weight and a more stable structure. If the ratio exceeds the range, the ethylene-vinyl acetate copolymer cannot completely react with polybutylene succinate, and the excess ethylene-vinyl acetate copolymer or polybutylene succinate is distributed in the graphene anticorrosive coating, which increases the porosity of the graphene anticorrosive coating and reduces the adhesion.

[0085] In the embodiment of the present application, at a specific temperature (the temperature in S4-S6), the activated graphene oxide reacts with sodium methylsilanolate, ethylene-vinyl acetate copolymer and polybutylene succinate to generate a high molecular compound. The activated graphene oxide and nanomaterials play a role of a bridge, and the newly generated chemical bonds connect sodium methylsilanolate, ethylene-vinyl acetate copolymer and polybutylene succinate, so that sodium methylsilanolate, ethylene-vinyl acetate copolymer and polybutylene succinate are polymerized around the graphene oxide and nanomaterials to generate a high molecular material with a larger molecular weight and a more stable structure, rather than simply playing a role of uniform distribution or filling pores. The high molecular compound further reacts with epoxy resin to generate a high-strength reticular structure film, which overcomes the problems of unstable molecular structure, easy aging and many pores of traditional epoxy coatings. If polybutylene succinate does not participate in the reaction, it is a mixture of ethylene-vinyl acetate copolymer, tetraethyl orthosilicate and polybutylene succinate, which has a smaller molecular weight, an unstable structure, is easy to oxidize when exposed to air, is easy to age, and has poor durability.

[0086] Example 5 is that the reaction temperature is out of the specified range, resulting in incomplete reaction of raw materials, larger internal pores, decreased adhesion, and decreased corrosion resistance of the prepared steel structure corrosion-resistant coating. During testing, there are a small amount of bubbles, cracking, peeling, and rusting defects on the surface. In S2, the reaction temperature is 110°C for activating succinic acid and butanediol, which is too low to reach the activation temperature of succinic acid and butanediol, resulting in incomplete activation and affecting the generation of polybutylene succinate in S3. In S4, the reaction temperature is 200°C, which is too low to break the hydrogen bonds of ethylene-vinyl acetate copolymer and tetraethyl orthosilicate, and cannot promote the reaction of ethylene-vinyl acetate copolymer, tetraethyl orthosilicate, and polybutylene succinate. In S5, the reaction temperature is 350°C, which is too high to destroy the structure of ammonium salt, promote the breakage of NH4 - in ammonium salt, and generate ammonia gas, which cannot play a catalytic role.

[0087] Comparative Example 1,

[0088] In S4, the heating temperature is 300°C or 150°C (out of the range of 200-250°C), and the remaining steps are the same as those in Example 2.

[0089] Comparative Example 2,

[0090] In S5, the heating temperature is 180°C (out of the range of 130-140°C), and the remaining steps are the same as those in Example 2.

[0091] Comparative Example 3,

[0092] In S6, the heating temperature is 10°C or 30°C (out of the range of 20-25°C), and the remaining steps are the same as those in Example 2.

[0093] Comparative Examples 1-3 are difficult to generate stable graphene oxide polymer steel structure corrosion-resistant coating, and the generated compounds have small molecular weights and unstable structures. In the marine corrosion environment with more air moisture, chloride ions, and the like, the coating is easily subjected to oxidation reaction, carbonization reaction, and the like, resulting in rapid aging, bubbling, cracking, and peeling of the coating.

[0094] The above only describes preferred embodiments of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, and the like made within the spirit and principles of the present application are included in the protection scope of the present application.

Claims

1. A method for preparing a graphene anticorrosive coating for steel structures suitable for marine corrosive environments, characterized by, It comprises the following steps: Step S1, according to the following quality parts of each raw material: graphene oxide 10~20 parts, epoxy resin 100~200 parts, dispersing agent 50~100 parts, nanometer material 5~10 parts, surfactant 30~50 parts, ethylene-vinyl acetate copolymer 30~50 parts, succinic acid 20~50 parts, butanediol 30~75 parts, tetraethyl orthosilicate 10~20 parts, sodium methylsilanol 500~600 parts, catalyst 3~5 parts, tyrosine 10~20 parts; the nanometer material is nano Al2O3 or nano CaO; Step S2, at 20 ℃~25 ℃, the weighed succinic acid, butanediol is put into the reaction kettle in turn, add magnet, and the magnet speed is adjusted to 500~800 r / min, mechanical stirring 0.5~1h, make it fully mixed, and carry out activation in oil bath at 110~120℃ for 1~2h; Step S3, add the weighed catalyst to the activated mixture, and adjust the magnet speed to 400~600 r / min, the oil bath temperature to 230℃~250 ℃, mechanical stirring for 5~6h, then cool to 50~60℃, get activated polybutylene succinate; Step S4, the weighed ethylene-vinyl acetate copolymer, tetraethyl orthosilicate is poured into the reaction kettle, heated to 200~250℃, and mechanically stirred at 1000~1500 r / min speed by using magnet for 4h~5h, then cooled to 30~40℃, mechanical stirring at 300~500 r / min speed for 6h~8h; Step S5, the weighed graphene oxide, nanometer material, dispersing agent is added into the reaction kettle in turn, at 130℃~140℃, the magnet speed is adjusted to 800~1000 r / min, mechanical stirring for 0.5~1h, then add the weighed surface activator, heat to 170℃~180 ℃, mechanical stirring for 1.5~2h, then add the weighed tyrosine, heat to 80℃~100℃, 6~8h after the reaction is completed, cool to room temperature; Step S6, then add the weighed epoxy resin, sodium methylsilanol into the reaction kettle in turn, at 20 ℃~25 ℃, the magnet speed is adjusted to 1500~2000 r / min, high speed stirring for 3~4h, then the steel structure graphene anticorrosive coating suitable for marine corrosion environment is obtained; The nanometer material is rich in metal cations, which ionizes metal cations in solution, and then promotes the displacement reaction of metal cations with sodium methylsilanol to generate more stable methylsilanol-based polymer compounds; In step S2, the molar ratio of succinic acid to butanediol is 1:1.5~3.

2. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, The dispersing agent is alcohol, ethylene glycol or ethylenediaminetetraacetic acid.

3. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, The surfactant is one or more of ammonium salt, quaternary ammonium salt, alcohol ether strong acid salt.

4. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, The catalyst is one or more of ethylene glycol antimony or titanium alcoholate.

5. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, In step S3, the catalyst dosage is 0.05~0.2 of the total mass of succinic acid and butanediol.

6. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, In step S4, the ratio of ethylene-vinyl acetate copolymer to tetraethyl orthosilicate is 2~3:

1.

7. The method of claim 1, wherein the graphene anticorrosive coating for steel structures in marine corrosive environments is characterized by, The mass of the tyrosine is 0.3-0.4 of the mass of the ethylene-vinyl acetate copolymer in the step S5. The mass of the tyrosine is 0.3-0.4 of the mass of the ethylene-vinyl acetate copolymer in the step S5.

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