A polyurethane composite coating based on active and passive protective structures and a method for producing the same

Abstract

This invention discloses a polyurethane composite coating based on an active and passive protective structure and its preparation method, relating to the field of functionalized friction-reducing and corrosion-resistant technology. The polyurethane composite coating provided by this invention is obtained by mixing a certain proportion of active and passive protective structure GO nanosheets, isophorone diisocyanate, polyether polyol, toluene, and N,N-dimethylformamide, and then spraying and curing the mixture onto a substrate surface. The active and passive protective structure GO nanosheets are GO nanosheets grafted with hydroxyl disulfide benzothiazole. The polyurethane composite coating provided by this invention exhibits significant friction-reducing effects and corrosion-resistant properties, and has potential application value in the field of marine corrosion protection.

Description

Technical Field

[0001] This invention relates to the field of friction reduction and corrosion prevention technology, specifically to a polyurethane composite coating based on an active and passive protection structure and its preparation method. Background Technology

[0002] In the marine environment, metallic materials are damaged and fail due to the interaction of seawater corrosion and wear, severely restricting the development of the marine industry. my country is actively promoting the development and utilization of marine energy through the construction of offshore wind farms and the use of tidal power generation. my country's independently developed high-end equipment has been successively deployed to near-shore areas and entered large-scale service. However, these marine engineering equipment are immersed in seawater for extended periods, causing severe corrosion to the metallic materials exposed to the marine atmosphere. Simultaneously, various friction and wear problems often occur during the operation of marine engineering equipment, leading to equipment wear and damage, thus accelerating the damage and failure of metallic materials. This has become a bottleneck restricting the efficient, stable, and long-term service life of modern marine engineering equipment. Current marine engineering equipment materials (such as titanium alloys, copper alloys, and nickel alloys) cannot fully meet the long-term operational requirements of rotating systems or other components of marine engineering equipment exposed to the marine environment. Therefore, how to solve the component failure problem caused by corrosion and wear of rotating systems, anchor chains, or other components in the marine environment is a pressing technical challenge in the field of marine engineering equipment. Therefore, innovation and research are needed in material selection, surface treatment and coating technology to improve the corrosion resistance and friction reduction performance of equipment components.

[0003] Polyurethane is widely used as a topcoat in marine coatings due to its excellent wear resistance, weather resistance, corrosion resistance, chemical stability, adhesion, and tunable hard and soft segments. However, the presence of highly polar groups in polyurethane molecules, such as urea, urethane, amide, and other groups with high surface energy, means that these molecules accumulate heat under cyclic alternating stress, further disrupting the polymer's cross-linking structure. This results in a higher coefficient of friction in the polyurethane coating during friction, leading to more severe corrosion and wear. To meet the requirements of high reliability and long service life for polyurethane coatings in marine environments, composite functional fillers, such as GO, can be added as friction-reducing and corrosion-resistant fillers to provide excellent friction-reducing and corrosion-resistant properties. However, GO sheets exhibit significant interlayer van der Waals forces, making them prone to aggregation and even causing localized defects in the resin, affecting its performance. Therefore, before GO nanosheets are added to the polyurethane matrix, surface modification is necessary to improve their interfacial compatibility with the polymer and prevent aggregation that could affect dispersibility, thus ensuring their environmental adaptability.

[0004] In summary, based on the concept of synergistic chemical and physical action and unified friction reduction and corrosion prevention, this invention aims to provide a special nanostructure that combines active chemical corrosion inhibition with passive physical barrier defense, and the synergistic combination of functional components. This will overcome the bottleneck of existing lubricating coatings that cannot simultaneously provide lubrication and corrosion prevention under harsh working conditions, and obtain a high-performance, long-life, friction-reducing and corrosion-resistant integrated coating to meet the usage requirements of marine engineering equipment in harsh environments. Summary of the Invention

[0005] The purpose of this invention is to provide a polyurethane composite coating based on an active and passive protection structure and its preparation method, so as to improve the friction reduction and corrosion protection of materials in marine and other environments.

[0006] To achieve the above objectives, the present invention provides a polyurethane composite coating based on an active and passive protection structure. The coating comprises, by weight, the following raw materials: 0.01 to 0.1 parts of GO nanosheets for active and passive protection, 5 to 10 parts of isophorone diisocyanate, 5 to 10 parts of polyether polyol, and 20 to 40 parts of solvent; wherein the GO nanosheets for active and passive protection are GO nanosheets grafted with benzothiazole disulfide.

[0007] Preferably, the hydroxydisulfide benzothiazole is prepared in-house, and the preparation process is as follows:

[0008] (1) Mix 0.01-0.1 mol of dibenzothiazole disulfide and 500-100 mL of chloroform, then add 0.01-0.1 mol of β-mercaptoethanol dropwise, and carry out the reaction under stirring conditions. The reaction temperature is 20-30℃ and the stirring time is 3-4 h.

[0009] (2) After the reaction, hydroxybenzothiazole disulfide was obtained. It was extracted with 3-5% NaOH aqueous solution and deionized water, dried with Na2SO4 and filtered. After rotary evaporation, it was purified by recrystallization with n-hexane to obtain the treated hydroxybenzothiazole disulfide.

[0010] Preferably, the polyurethane composite coating comprises, by weight, the following raw materials: 0.02-0.06 parts of GO nanosheets for active and passive protection, 6-9 parts of isophorone diisocyanate, 8-10 parts of polyether polyol, and 28-32 parts of solvent.

[0011] Preferably, the preparation method of the above-mentioned active and passive protection structure GO nanosheets includes the following steps:

[0012] (1) Mix GO nanosheets and N,N-dimethylformamide and sonicate to obtain a GO nanosheet mixture;

[0013] (2) The obtained GO nanosheet mixture was mixed with hydroxydisulfide benzothiazole and N,N-dimethylformamide, stirred, and then centrifuged, washed and dried to obtain the active and passive protection structure GO nanosheet.

[0014] Preferably, in step (1) above, the ratio of GO nanosheets to N,N-dimethylformamide is 0.5-1g:100-300mL, and the sonication time is 30-40min.

[0015] Preferably, the obtained GO nanosheet mixture is mixed with benzothiazole disulfide and N,N-dimethylformamide, wherein the ratio of benzothiazole disulfide to N,N-dimethylformamide is 0.5-1 g: 100-300 mL; the mixture is stirred, preferably at a temperature of 55-65°C, a stirring speed of 200-300 rpm, and a stirring time of 5-6 h; centrifugation is performed at 8000 rpm for 10 min; and washing is performed by alternating washing with ethanol and deionized water.

[0016] Preferably, the polyether polyol in the polyurethane composite coating is one or more of NX9005, NX9006 or NX9007; the solvent is a mixture of toluene and N,N-dimethylformamide in a mass ratio of 1-2g:1g.

[0017] The present invention also provides a method for preparing the above-mentioned polyurethane composite coating, comprising the following steps:

[0018] (1) Mix the active and passive protection structure GO nanosheets, isophorone diisocyanate and solvent to obtain a mixed slurry;

[0019] (2) Add polyether polyol to the obtained mixed slurry to obtain polyurethane composite slurry;

[0020] (3) The obtained polyurethane composite slurry is sprayed onto the surface of the substrate and cured to obtain a polyurethane composite coating with friction reduction and corrosion resistance.

[0021] The present invention has the following advantages:

[0022] 1) This invention modifies GO by esterification with MBTS2OH, enhancing the dispersion stability of GO in the coating and its interfacial compatibility with polyurethane adhesives. The lamellar structure of GO, when stacked within the coating, forms a "maze effect" that extends the penetration path of corrosive media. Furthermore, the breaking of disulfide bonds in MBTS2OH releases corrosion inhibitors, thereby improving the corrosion resistance of the coating in marine environments.

[0023] 2) The coating of this invention uses polyurethane as the base material, which has chemical stability, adhesion, and adjustable hard and soft segments. This invention uses surface-modified GO as a wear-resistant and corrosion-resistant filler, which not only has excellent lubrication performance but also excellent corrosion resistance, thus significantly improving the corrosion resistance and friction-reducing properties of the coating.

[0024] 3) The integrated marine friction-reducing and corrosion-resistant coating of this invention, by introducing friction-reducing and corrosion-resistant fillers, enables the coating to possess both excellent friction-reducing and corrosion-resistant functions. Under dry friction conditions, the coating exhibits good tribological properties. This coating improves the corrosion-resistant and friction-reducing performance of organically bonded coatings exposed to the marine environment for extended periods, reducing damage and failure problems caused by high-load impacts and mechanical wear. Attached Figure Description

[0025] Figure 1 This is a physical image of the friction-reducing and corrosion-resistant coating obtained in Embodiment 1 of the present invention.

[0026] Figure 2 The results show the tribological properties of the friction-reducing and corrosion-resistant coatings obtained in the comparative examples and embodiments of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Note: Unless otherwise specified, the experimental methods in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0029] This invention provides a polyurethane composite coating based on an active and passive protection structure, comprising the following raw materials by mass: 0.01-0.1 parts of active and passive protection GO nanosheets, 5-10 parts of isophorone diisocyanate, 5-10 parts of polyether polyol, and 20-40 parts of solvent; wherein the active and passive protection structure GO nanosheets are GO nanosheets grafted with hydroxyl disulfide benzothiazole.

[0030] The preparation method of the active and passive protection structure GO nanosheets is as follows:

[0031] (1) GO nanosheets and N,N-dimethylformamide were first mixed and then sonicated to obtain a GO nanosheet mixture;

[0032] (2) The GO nanosheet mixture, hydroxydisulfide benzothiazole and N,N-dimethylformamide were mixed and modified to obtain GO nanosheets with active and passive protection structure.

[0033] The GO nanosheets are preferably monolayer GO nanosheets with a thickness of 1 nm. The ratio of GO nanosheets to N,N-dimethylformamide is (0.5-1) g:(100-300) mL, preferably 0.8 g:100-300 mL, more preferably 0.8 g:150-200 mL, and most preferably 0.8 g:200 mL. The sonication of the first mixture is for 30-40 min, preferably 30-35 min, and most preferably 30 min.

[0034] The obtained GO nanosheet mixture was mixed with hydroxybenzothiazole disulfide and N,N-dimethylformamide in a second mixture. The ratio of hydroxybenzothiazole disulfide to N,N-dimethylformamide was (0.5-1) g:(100-300) mL, more preferably (0.5-0.8) g:(200-300) mL, and most preferably 0.6 g:200 mL.

[0035] The stirring is carried out under stirring conditions, with the stirring temperature preferably being 55-65℃, more preferably 60-65℃, and most preferably 60℃; the stirring temperature is preferably achieved by heating in an oil bath; the stirring speed is preferably 200-300 rpm, more preferably 250-300 rpm, and most preferably 250 rpm; the stirring time is preferably 5-6 hours, more preferably 5.5-6 hours, and most preferably 6 hours.

[0036] The hydroxybenzothiazole disulfide used in the preparation of the above-mentioned active and passive protection structure GO nanosheets was prepared in-house, and the specific preparation process is as follows:

[0037] (1) Dibenzothiazole disulfide and chloroform are mixed, and then β-mercaptoethanol is added dropwise. The reaction is carried out under stirring conditions. The preferred ratio of the amount of dibenzothiazole disulfide, chloroform and β-mercaptoethanol is (0.01-0.1) mol: (500-100) mL: (0.01-0.1) mol, more preferably (0.02-0.08) mol: (800-1000) mL: (0.02-0.08) mol, and most preferably 0.05 mol: 800 mL: 0.05 mol. The preferred reaction temperature is 20-30°C, more preferably 25-30°C, and most preferably 25°C. The preferred stirring speed is 200-300 rpm, more preferably 250 rpm. The preferred stirring time is 3-4 h, more preferably 3.5-4 h, and most preferably 4 h.

[0038] (2) After the reaction, hydroxybenzothiazole disulfide was obtained. It was then extracted with NaOH aqueous solution and deionized water, dried with Na2SO4 and filtered. After rotary evaporation, it was purified by recrystallization with n-hexane to obtain the treated hydroxybenzothiazole disulfide.

[0039] The NaOH aqueous solution preferably has a mass fraction of 3-5%, more preferably 4-5%, and most preferably 5%; the extraction is preferably performed 4-6 times, more preferably 5-6 times, and most preferably 6 times; the rotary evaporation temperature is 50-70℃, more preferably 50-60℃, and most preferably 60℃; after the synthesis of benzothiazole disulfide is completed, it is preferably subjected to vacuum drying treatment at a temperature of 50-70℃, more preferably 60-70℃, and most preferably 70℃; the vacuum drying time is preferably 10-15h, more preferably 12-15h, and most preferably 12h.

[0040] Based on mass parts, the polyurethane composite coating provided by the present invention contains 0.01 to 0.1 parts of active and passive protective structure GO nanosheets, with a preferred ratio of 0.02 to 0.08 parts, and more preferably 0.02 to 0.06 parts.

[0041] The polyurethane composite coating provided by the present invention contains 5 to 10 parts of isophorone diisocyanate, preferably 6 to 10 parts, and more preferably 6 to 9 parts, based on parts by weight.

[0042] The polyurethane composite coating provided by the present invention comprises 5 to 10 parts of polyether polyol, preferably 6 to 10 parts, more preferably 8 to 10 parts, based on parts by weight; wherein the polyether polyol is preferably one or more of NX9005, NX9006 or NX9007.

[0043] The polyurethane composite coating provided by the present invention contains 20 to 40 parts of solvent, preferably 25 to 35 parts, and more preferably 28 to 32 parts by weight; the solvent is preferably a mixture of toluene and N,N-dimethylformamide, wherein the mass ratio of toluene to N,N-dimethylformamide in the mixture is 5 to 3:1, preferably 4:1, and more preferably 3:1.

[0044] This invention also provides a better method for preparing active and passive protection GO nanosheets, as detailed below:

[0045] 0.05 mol of dibenzothiazole disulfide (BSSB) was dissolved in 800 mL of chloroform (CHCl3), and 3.91 g of β-mercaptoethanol was slowly added dropwise. The mixture was stirred at 25 °C for 4 h to obtain a mixture. The mixture was first extracted 6 times with 5 wt% NaOH aqueous solution, then extracted 6 times with deionized water, dried with Na2SO4, filtered, and finally rotary evaporated at 60 °C to obtain hydroxybenzothiazole disulfide. The hydroxybenzothiazole disulfide was purified by recrystallization from n-hexane, and white needle-like crystals were collected and labeled MBTS2OH. The crystals were then dried under vacuum at 70 °C for 12 h.

[0046] On one hand, 0.6 g of benzothiazole disulfide and 200 mL of N,N-dimethylformamide (DMF) were added to a three-necked flask and dispersed evenly. On the other hand, 0.8 g of GO nanosheets were dispersed in 200 mL of DMF and ultrasonically dispersed for 30 min. Then, the mixture was poured into a three-necked flask and stirred in an oil bath at 60 °C for 6 h. The resulting mixture was centrifuged at 8000 rpm for 10 min. The resulting suspension was washed alternately with ethanol and deionized water to obtain GO modified with MBTS2OH (MBTS2GO). The GO nanosheets with active and passive protection structure were then dried in a freeze dryer for 12 h.

[0047] This invention also provides a method for preparing a polyurethane composite coating based on an active-passive protection structure, comprising the following steps:

[0048] (1) Mix the active and passive protection structure GO nanosheets, isophorone diisocyanate, polyether polyol and solvent to obtain a mixed slurry;

[0049] (2) The obtained mixed slurry is sprayed onto the surface of the substrate and cured to obtain a polyurethane composite coating with integrated friction reduction and corrosion protection functions.

[0050] Preferably, the active and passive protection structure GO nanosheets and solvent are first mixed with isophorone diisocyanate to obtain a mixture; then the mixture is mixed with polyether polyol to obtain a slurry. The first mixing is preferably carried out under stirring conditions, with a stirring speed preferably of 300-400 rpm, more preferably 320-380 rpm, and most preferably 350 rpm; the stirring time is preferably 1-4 h, more preferably 2-4 h, and most preferably 2 h.

[0051] The second mixing is preferably carried out under stirring conditions, with the stirring speed preferably being 300-400 rpm, more preferably 320-380 rpm, and most preferably 350 rpm; the stirring time is preferably 2-6 h, more preferably 2-4 h, and most preferably 4 h.

[0052] The substrate is preferably a substrate treated according to the national standard GB / T8923.1; the spraying conditions are preferably as follows: the distance between the mixed slurry and the substrate surface is preferably 20-25 cm, more preferably 21-24 cm, and most preferably 22-23 cm; the spraying is preferably carried out in compressed air at 0.15-0.20 MPa; the thickness of the coating after spraying is preferably 30-50 μm, more preferably 35-45 μm, and most preferably 38-40 μm.

[0053] The preferred curing temperature is programmed temperature increase curing, and the preferred curing temperature and time are 120℃ for 2 hours and then 150℃ for 4 hours.

[0054] The polyurethane composite coating provided by this invention has both friction-reducing and corrosion-resistant functions, and has potential application value in the field of marine corrosion protection.

[0055] Example 1

[0056] This embodiment provides a method for preparing a polyurethane composite coating, comprising the following raw materials by mass: 0.05 parts of active and passive protective structure GO nanosheets (MBTS2GO), 8.8 parts of isophorone diisocyanate (IPDI), 10 parts of polyether polyol (specifically NX9005), 20 parts of toluene, and 10 parts of N,N-dimethylformamide. The preparation process is as follows:

[0057] MBTS2GO and isophorone diisocyanate were added to a mixture of toluene and N,N-dimethylformamide and stirred (350 rpm for 2 h). Then, polyether polyol was added dropwise and stirred in a nitrogen atmosphere at 70 °C (350 rpm for 4 h) to obtain polyurethane (PU) composite slurry.

[0058] The obtained polyurethane composite slurry was sprayed onto the surface of a substrate (Q235 steel) treated according to national standard GB / T8923.1, cured at 120℃ for 4 hours, and then cured at 150℃ for 2 hours to obtain an integrated polyurethane composite coating with friction-reducing and anti-corrosion functions (MBTS2GO / PU). The actual appearance is as follows. Figure 1 As shown.

[0059] Comparative Example 1

[0060] This comparative example provides an integrated coating with friction-reducing and corrosion-resistant functions. The raw materials used in its preparation (by mass parts) include: 8.8 parts isophorone diisocyanate (IPDI), 10 parts polyether polyol (specifically NX9005), 20 parts toluene, and 10 parts N,N-dimethylformamide. The preparation process is as follows:

[0061] First, isophorone diisocyanate, toluene and N,N-dimethylformamide are mixed, and then polyether polyol is added dropwise. The mixture is stirred in a nitrogen atmosphere at 70°C (350 rpm for 4 hours) to obtain polyurethane (PU) slurry.

[0062] The obtained polyurethane slurry was sprayed onto the surface of a substrate (Q235 steel) treated according to the national standard GB / T8923.1, cured at 120℃ for 4 hours, and then heated to 150℃ for 2 hours to obtain an integrated coating (PU) with friction-reducing and anti-corrosion functions.

[0063] Comparative Example 2

[0064] This comparative example provides an integrated coating with friction-reducing and corrosion-resistant functions. The raw materials used in its preparation include (by mass parts): 0.05 parts of GO nanosheets, 8.8 parts of isophorone diisocyanate (IPDI), 10 parts of polyether polyol (specifically NX9005), 20 parts of toluene, and 10 parts of N,N-dimethylformamide.

[0065] First, GO and isophorone diisocyanate were added to a mixture of toluene and N,N-dimethylformamide and stirred (at 350 rpm for 2 hours). Then, polyether polyol was added dropwise and stirred under a nitrogen atmosphere at 70°C (at 350 rpm for 4 hours) to obtain a polyurethane (PU) composite slurry.

[0066] The obtained polyurethane composite slurry was sprayed onto the surface of a substrate (Q235 steel) treated according to the national standard GB / T8923.1, cured at 120℃ for 4 hours, and then heated to 150℃ for 2 hours to obtain an integrated coating with friction-reducing and anti-corrosion functions (GO / PU).

[0067] The tribological properties of the coatings obtained in Example 1, Comparative Example 1, and Comparative Example 2 were measured. The testing methods and performance data are shown in Table 1. All substrates were Q235 steel substrates. To avoid random errors, two sets of data are provided for the determination of the friction coefficient and coating wear rate in Table 1. The test results are as follows: Figure 2 As shown, where, Figure 2 In the figure, 'a' represents the friction curves of the three coatings under the conditions of 5N load, 5Hz frequency, and 100m sliding distance. Figure 2 In this context, b represents the average coefficient of friction and wear rate of the three coatings under conditions of 5N load, 5Hz frequency, and a sliding distance of 100m. Figure 2 The tribological behavior of the polyurethane-based composite coatings was shown. It can be seen that the coefficients of friction for the GO / PU and MBTS2GO / PU composite coatings are 0.26 and 0.22, respectively, which are lower than those for the pure PU coating (0.52). The wear rate of the polyurethane composite coatings was further investigated under dry friction conditions, such as... Figure 2As shown in b, the wear rate of the pure PU coating is 5.5 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 However, when graphene nanosheets are added as a reinforcing material, the wear rate of the coating decreases. In particular, the MBTS2GO / PU composite coating exhibits a low wear rate of only 3.14 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 Compared to GO / PU composite coatings and PU coatings, MBTS2GO / PU composite coatings exhibit better tribological properties.

[0068] Table 1. Test methods and performance data of the coatings obtained in Example 1 and Comparative Examples 1-2.

[0069]

[0070] As shown in Table 1, the integrated polyurethane composite coating with friction reduction and corrosion protection provided by the present invention has a low coefficient of friction and excellent corrosion resistance on the surface of low carbon steel substrate, and can be used for a long time in the marine environment. It can be seen that the polyurethane composite coating can be widely used in the friction reduction, salt resistance and corrosion protection of marine materials, and has application potential in the field of marine corrosion protection.

[0071] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A polyurethane composite coating based on an active-passive protection structure, characterized in that, The coating comprises, by weight, the following raw materials: 0.02-0.06 parts of GO nanosheets for active and passive protection, 6-9 parts of isophorone diisocyanate, 8-10 parts of polyether polyol, and 28-32 parts of solvent; The active and passive protection structure GO nanosheets are GO nanosheets grafted with hydroxydisulfide benzothiazole. The preparation process of the hydroxydisulfide benzothiazole is as follows: Mix 0.01–0.1 mol of dibenzothiazole disulfide with 500–100 mL of chloroform, then add 0.01–0.1 mol of β-mercaptoethanol dropwise. React under stirring at 20–30 °C for 3–4 h. The resulting hydroxybenzothiazole disulfide is extracted with 3–5% NaOH aqueous solution and deionized water, dried over Na₂SO₄ and filtered. After rotary evaporation, it is purified by recrystallization from n-hexane to obtain the treated hydroxybenzothiazole disulfide. The preparation method of the active and passive protection structure GO nanosheets includes the following steps: (1) Mix GO nanosheets and N,N-dimethylformamide and sonicate to obtain a GO nanosheet mixture; (2) The GO nanosheet mixture is mixed with benzothiazole disulfide and N,N-dimethylformamide, stirred, and then centrifuged, washed and dried to obtain the active and passive protection structure GO nanosheet.

2. The polyurethane composite coating according to claim 1, characterized in that, In step (1), the ratio of GO nanosheets to N,N-dimethylformamide is 0.5~1 g: 100~300 mL, and the sonication time is 30~40 min.

3. The polyurethane composite coating according to claim 1, characterized in that, The obtained GO nanosheet mixture was mixed with benzothiazole disulfide and N,N-dimethylformamide, wherein the ratio of benzothiazole disulfide to N,N-dimethylformamide was 0.5~1 g:100~300 mL; the stirring was carried out under the following conditions: stirring temperature was 55~65 ℃, stirring speed was 200~300 rpm, and stirring time was 5~6 h; the centrifugation was carried out at 8000 rpm for 10 min; the washing was carried out by alternating washing with ethanol and deionized water.

4. The polyurethane composite coating according to claim 1, characterized in that, The polyether polyol is one or more of NX9005, NX9006 or NX9007; the solvent is a mixture of toluene and N,N-dimethylformamide in a mass ratio of 1~2 g:1 g.

5. A method for preparing a polyurethane composite coating as described in any one of claims 1 to 4, characterized in that, It includes the following steps: (1) The active and passive protection structure GO nanosheets are mixed with isophorone diisocyanate and solvent to obtain a mixed slurry; (2) Add polyether polyol to the mixed slurry to obtain polyurethane composite slurry; (3) The polyurethane composite slurry is sprayed onto the surface of the substrate and cured to obtain a polyurethane composite coating with friction reduction and corrosion resistance. The thickness of the sprayed coating is 38~40μm; the curing is a programmed temperature curing, including curing at 120℃ for 2 hours and then curing at 150℃ for 4 hours.

Images