A bio-based polyurethane self-repairing super-hydrophobic anticorrosive liquid as well as a preparation method and application thereof

Abstract

A bio-based polyurethane self-repairing super-hydrophobic corrosion-resistant liquid and a preparation method and application thereof, which are prepared from cardanol as raw material through click reaction, Mannich reaction and cross-linking with -NCO to obtain a cardanol-based polyurethane containing a benzoxazine structure and a disulfide bond structure, and are combined with ZIF-8 nanoparticles loaded with corrosion inhibitors to obtain a coating material with self-repairing performance and super-hydrophobic performance, which can play a role in corrosion protection for metals. There are abundant disulfide bonds and polyurethane hydrogen bonds in the resin, and due to the dynamic and reversible cross-linking of the disulfide bonds and hydrogen bonds, the coating after scratching can be partially repaired under heating conditions, giving the coating self-healing performance and prolonging the service life of the coating. The benzoxazine structure makes the resin have low surface energy, and the ZIF-8 nanoparticles loaded with corrosion inhibitors construct a rough structure of the coating, and under the synergistic effect of the low surface energy and the rough structure, the coating has excellent super-hydrophobic performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of preparation of self-repairing super-hydrophobic anti-corrosion coating, and particularly relates to a bio-based polyurethane self-repairing super-hydrophobic anti-corrosion liquid, a preparation method and application thereof. BACKGROUND

[0002] Corrosion reactions between metals and corrosive media in the surrounding environment have a huge impact on the service life, economy and environment of metals. Among the many methods to slow down metal corrosion, such as adding corrosion inhibitors, improving the corrosion environment, electrochemical protection, coating protection, etc., constructing a coating on the surface of the metal, especially a super-hydrophobic coating with active hydrophobicity, has become an effective strategy. The coating on the surface of the metal is easily damaged physically or chemically during use, thereby losing the super-hydrophobic property or the anti-corrosion effect on the metal. Therefore, researchers introduce self-repairing properties into the coating to prolong the service life of the coating.

[0003] Polyurethane has good adhesion, flexible molecular structure control, good mechanical properties, etc. Its molecular structure contains a large number of hydrophilic hydrogen bonds, which may cause the polyurethane coating to absorb corrosive liquids. The introduction of hydrophobic benzoxazine structure and low-surface-energy polydimethylsiloxane long-chain segments into the polyurethane structure can increase the hydrophobicity of polyurethane, making it more suitable for metal anti-corrosion coatings. Disulfide bond is a dynamic covalent bond that can undergo reversible crosslinking, and its rupture and recombination in materials endow the materials with self-repairing properties. The introduction of disulfide bond into polyurethane materials, under the combined action of disulfide bond and reversible non-covalent hydrogen bond, the materials have good self-repairing properties. At present, most of the coating materials in practical application are prepared based on non-renewable petrochemical resources. In the face of the increasing depletion of petrochemical resources and environmental pollution, researchers are constantly seeking raw materials to replace petrochemical resources. Cashew phenol is a natural phenolic compound extracted from cashew nut shell, which contains benzene ring, conjugated double bond and other reactive sites in its molecular structure. Utilizing cashew phenol not only can improve the utilization rate of agricultural and forestry wastes and produce high-value-added products, but also can promote the further development of green and environmentally friendly bio-based materials. SUMMARY

[0004] The technical problem to be solved is to solve the problems of metal corrosion and easy damage of super-hydrophobic anti-corrosion coating on metal, and the present application provides a cashew phenol-based polyurethane self-repairing super-hydrophobic anti-corrosion liquid with good anti-corrosion property, mechanical stability and environmental stability, and a preparation method and application thereof.

[0005] Technical solution: A preparation method of a bio-based polyurethane self-repairing super-hydrophobic corrosion-resistant liquid, comprising the following steps: (1) adding cardanol, beta-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) into a reactor, the molar ratio of cardanol and beta-mercaptoethanol being 1:(6-12), Irgacure-184 being 0.5-3% of the total mass of the reactants, and the catalyst being 0.5-2% of the total mass of the reactants, then heating the reactor to 80-100°C under ultraviolet light (λ=375nm) for 8-24h to obtain a cardanol-based polyol; (2) adding the cardanol-based polyol, paraformaldehyde and aminopropyl-terminated polydimethylsiloxane (NH2-PDMS, molecular weight 1000-2000g·mol -1 ) into the reactor, the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde being 2:1:(4-10), heating the reactor to 90-110°C for 8-12h to obtain a cardanol-based benzoxazine resin; (3) adding the cardanol-based benzoxazine resin, isophorone diisocyanate (IPDI), bis(2-aminophenyl)disulfide (DTDA) and a catalyst into another reactor, the molar ratio of the hydroxyl groups in the cardanol-based benzoxazine resin, the amino groups in the DTDA and the -NCO groups in the IPDI being (0.9-0.1):(0.1-0.9):(1-1.1), the catalyst being added in an amount of 0.5-2% of the total mass of the reactants, heating the reactor to 60-80°C for 4-8h to obtain a cardanol-based polyurethane; (4) adding the cardanol-based polyurethane obtained in step (3) and ZIF-8 nanoparticles loaded with corrosion inhibitors into an organic solvent, the mass-volume ratio of the cardanol-based polyurethane to the organic solvent being (0.1-0.5)g:10mL, the mass of the ZIF-8 nanoparticles loaded with corrosion inhibitors being 60-100% of the mass of the cardanol-based polyurethane, and after ultrasonic dispersion for 15-30min, a super-hydrophobic coating dispersion is obtained.

[0006] In step (1), the molar ratio of the cardanol and beta-mercaptoethanol is 1:10, Irgacure-184 is 1% of the total mass of the reactants, and the catalyst DBU is 1% of the total mass of the reactants.

[0007] In step (2), the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde is 2:1:6.

[0008] In step (3), the catalyst is at least one of dibutyltin dilaurate and 1,4-diazabicyclo[2.2.2]octane, and the catalyst is added in an amount of 1% of the total weight of the raw materials.

[0009] The corrosion inhibitor in step (4) is at least one of methionine, histidine, arginine and glycine, the organic solvent is at least one of butanone, ethyl acetate and tetrahydrofuran, the mass-volume ratio of the cashew phenol-based polyurethane and the organic solvent is 0.1 g:5 mL, the mass of the ZIF-8 nanoparticles loaded with the corrosion inhibitor is 60% of the mass of the cashew phenol-based polyurethane, and the ultrasonic dispersion time is 20 min.

[0010] The particle size of the ZIF-8 nanoparticles loaded with the corrosion inhibitor in step (4) is 100-800 nm, and the synthesis method comprises the following steps: dispersing ZIF-8 nanoparticles, a corrosion inhibitor, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in distilled water, wherein the ratio of ZIF-8, the corrosion inhibitor, EDC, DMAP and distilled water is 0.5 g:0.3 g:0.01 g:0.01 g:50 mL, and then the mixture is reacted at 80-100 DEG C for 2-6 h; after the reaction is completed, the precipitate is collected by centrifugation, the precipitate is washed with distilled water, and the precipitate is dried in a vacuum drying oven at 60-100 DEG C for 2-24 h.

[0011] The anticorrosive liquid prepared by the method.

[0012] The anticorrosive liquid is applied in the preparation of a metal anticorrosive coating. The super-hydrophobic coating dispersion liquid is uniformly sprayed on a metal substrate at a spraying distance of 10-20 cm and a spraying pressure of 0.2 MPa, and then the metal substrate coated with the coating is heat-cured to obtain a self-repairing super-hydrophobic anticorrosive coating. The spraying distance is 15 cm, and the curing process is curing at 160 DEG C for 2 h, at 180 DEG C for 2 h and at 200 DEG C for 2 h in sequence.

[0013] Beneficial effects: (1) The cashew phenol-based polyurethane containing a benzoxazine structure and a disulfide bond structure is obtained by a click reaction, a Mannich reaction and crosslinking with -NCO, and the coating material with self-repairing performance and super-hydrophobic performance is obtained by combining the cashew phenol-based polyurethane with the ZIF-8 nanoparticles loaded with the corrosion inhibitor, and the coating material can play an anticorrosive role on the metal.

[0014] (2) There are rich disulfide bonds and polyurethane hydrogen bonds in the resin, and due to the dynamic reversible crosslinking of the disulfide bonds and the hydrogen bonds, the coating after scratching can be partially repaired under heating conditions, so that the self-healing performance of the coating is given, and the service life of the coating is prolonged.

[0015] (3) The benzoxazine structure makes the resin have low surface energy, and the ZIF-8 nanoparticles loaded with corrosion inhibitors construct a rough structure of the coating, so that the coating has excellent super-hydrophobic performance under the synergistic effect of low surface energy and rough structure. In addition, the corrosion inhibitor loaded on the surface of the ZIF-8 nanoparticles can effectively improve the corrosion resistance of the coating at the scratch, and together with the self-healing performance of the coating, the coating is endowed with the self-healing and corrosion double-effect self-repairing function.

[0016] (4) The main raw material of the synthetic resin in the present application is cashew phenol, which is extracted from agricultural and forestry wastes, thereby improving the utilization rate of the agricultural and forestry wastes; and the preparation process of the coating is relatively simple, which is conducive to large-scale popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Synthetic route of the cashew phenol-based polyurethane prepared in step (3) of claim 1;

[0018] Figure 2 FT-IR spectrum of the cashew phenol-based polyurethane prepared in step (3) of claim 1. DETAILED DESCRIPTION

[0019] The following examples of the present application are only used to further illustrate the content of the present application, and cannot be used as the limited content or range of the present application. The present application will be further described in detail in combination with the examples.

[0020] Example 1

[0021] (1) Preparation of ZIF-8 nanoparticles loaded with corrosion inhibitors: 1.34 g of zinc nitrate hexahydrate was dissolved in 8.66 g of deionized water, and stirred to dissolve at room temperature to prepare solution A; 25.86 g of 2-methylimidazole was dissolved in 64.14 g of deionized water, and stirred to dissolve at room temperature to prepare solution B; then solution A was poured into solution B, and mechanical stirring was continued in a constant-temperature water bath at room temperature for 24 h (at a speed of 400 rpm). After the reaction was completed, the mixed solution was left to stand at room temperature for 24 h, and white particles were separated and collected by a high-speed centrifuge (at a speed of 7000 rpm for 15 min), and washed with ultrapure water for 3 times to obtain ZIF-8 nanoparticles. 0.5 g of ZIF-8 nanoparticles, 0.3 g of corrosion inhibitor methionine, 0.01 g of EDC and 0.01 g of DMAP were dispersed in 50 mL of distilled water, and reacted at 100℃ for 4 h. After the reaction was completed, the precipitate was collected by centrifugation, washed with distilled water, and dried in a vacuum drying oven at 80℃ for 12 h. Finally, ZIF-8 nanoparticles loaded with the corrosion inhibitor methionine were obtained.

[0022] Example 2

[0023] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0024] (2) Into another reactor, the cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0025] (3) Into another reactor, the cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of the hydroxyl group in the cardanol-based benzoxazine resin, the amino group in the DTDA and the -NCO group in the IPDI was 0.8:0.2:1.1, the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0026] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of the cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of the ZIF-8 nanoparticles loaded with corrosion inhibitor was 60% of the mass of the cardanol-based polyurethane, and ultrasonic dispersion was performed for 20 min, to obtain a super-hydrophobic coating dispersion;

[0027] (5) The super-hydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing super-hydrophobic corrosion-resistant coating.

[0028] Example 3

[0029] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0030] (2) Into another reactor, the cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0031] (3) Into another reactor, the cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of the hydroxyl group in the cardanol-based benzoxazine resin, the amino group in the DTDA and the -NCO group in the IPDI was 0.6:0.4:1.1, the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0032] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of the cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of the ZIF-8 nanoparticles loaded with corrosion inhibitor was 60% of the mass of the resin, and the ultrasonic dispersion time was 20 min, to obtain a super-hydrophobic coating dispersion;

[0033] (5) The super-hydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing super-hydrophobic corrosion-resistant coating.

[0034] Example 4

[0035] (1) The cashew phenol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added into the reactor, the molar ratio of cashew phenol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24h, to obtain cashew phenol-based polyol;

[0036] (2) The cashew phenol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added into the reactor, the molar ratio of cashew phenol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12h, to obtain cashew phenol-based benzoxazine resin;

[0037] (3) The cashew phenol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added into another reactor, the molar ratio of hydroxyl in cashew phenol-based benzoxazine resin, amino in DTDA and -NCO group in IPDI was 0.4:0.6:1.1, the catalyst was added in an amount of 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5h, to obtain cashew phenol-based polyurethane;

[0038] (4) The obtained cashew phenol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of cashew phenol-based polyurethane and tetrahydrofuran was 0.1g:5mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor was 60% of the mass of the resin, and ultrasonic dispersion was carried out for 20min, to obtain a superhydrophobic coating dispersion;

[0039] (5) The superhydrophobic coating dispersion was uniformly sprayed on the metal substrate, the spraying distance was 15cm, and the spraying pressure was 0.2MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to the curing process of curing at 160°C for 2h, curing at 180°C for 2h and curing at 200°C for 2h, to obtain a self-repairing superhydrophobic corrosion-resistant coating.

[0040] Example 5

[0041] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0042] (2) Into a reactor, cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0043] (3) Into another reactor, cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of hydroxyl groups in the cardanol-based benzoxazine resin, amino groups in the DTDA and -NCO groups in the IPDI was 0.2:0.8:1.1, the catalyst was added in an amount of 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0044] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor was 60% of the mass of the resin, and ultrasonic dispersion was performed for 20 min, to obtain a superhydrophobic coating dispersion;

[0045] (5) The superhydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing superhydrophobic corrosion-resistant coating.

[0046] Example 6

[0047] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0048] (2) Into a reactor, cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0049] (3) Into another reactor, cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of hydroxyl groups in the cardanol-based benzoxazine resin, amino groups in the DTDA and -NCO groups in the IPDI was 0.4:0.6:1.1, the catalyst was added in an amount of 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0050] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor was 65% of the mass of the resin, and ultrasonic dispersion was performed for 20 min, to obtain a superhydrophobic coating dispersion;

[0051] (5) The superhydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing superhydrophobic corrosion-resistant coating.

[0052] Example 7

[0053] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0054] (2) Into a reactor, the cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0055] (3) Into another reactor, the cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of the hydroxyl group in the cardanol-based benzoxazine resin, the amino group in the DTDA and the -NCO group in the IPDI was 0.4:0.6:1.1, the catalyst was added in an amount of 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0056] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of the cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of the ZIF-8 nanoparticles loaded with corrosion inhibitor was 70% of the mass of the resin, and ultrasonic dispersion was performed for 20 min, to obtain a superhydrophobic coating dispersion;

[0057] (5) The superhydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing superhydrophobic corrosion-resistant coating.

[0058] Example 8

[0059] (1) Into a reactor, cardanol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added, the molar ratio of cardanol and β-mercaptoethanol was 1:10, the mass fraction of Irgacure-184 was 1% of the total mass of the reactants, and the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24 h, to obtain a cardanol-based polyol;

[0060] (2) Into a reactor, the cardanol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added, the molar ratio of the cardanol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12 h, to obtain a cardanol-based benzoxazine resin;

[0061] (3) Into another reactor, the cardanol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added, the molar ratio of the hydroxyl group in the cardanol-based benzoxazine resin, the amino group in the DTDA and the -NCO group in the IPDI was 0.4:0.6:1.1, the mass fraction of the catalyst was 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5 h, to obtain a cardanol-based polyurethane;

[0062] (4) The obtained cardanol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added into tetrahydrofuran, the mass-volume ratio of the cardanol-based polyurethane and tetrahydrofuran was 0.1 g:5 mL, the mass of the ZIF-8 nanoparticles loaded with corrosion inhibitor was 75% of the mass of the resin, and ultrasonic dispersion was performed for 20 min, to obtain a super-hydrophobic coating dispersion;

[0063] (5) The super-hydrophobic coating dispersion was uniformly sprayed on a metal substrate, the spraying distance was 15 cm, and the spraying pressure was 0.2 MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to a curing process of curing at 160°C for 2 h, curing at 180°C for 2 h and curing at 200°C for 2 h, to obtain a self-repairing super-hydrophobic corrosion-resistant coating.

[0064] Example 9

[0065] (1) The cashew phenol, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) were added to the reactor, the molar ratio of cashew phenol and β-mercaptoethanol was 1:10, the mass of Irgacure-184 was 1% of the total mass of the reactants, and the mass of the catalyst was 1% of the total mass of the reactants, the reaction was carried out under the condition of ultraviolet light (λ = 375 nm), the reaction temperature was 90°C, and the reaction time was 24h, to obtain cashew phenol-based polyol;

[0066] (2) The cashew phenol-based polyol, paraformaldehyde (Shanghai National Pharmaceutical Group, analytical pure) and NH2-PDMS (molecular weight 1000 g·mol -1 ) were added to the reactor, the molar ratio of cashew phenol-based polyol, NH2-PDMS and paraformaldehyde was 2:1:6, the reaction temperature was 90°C, and the reaction time was 12h, to obtain cashew phenol-based benzoxazine resin;

[0067] (3) The cashew phenol-based benzoxazine resin, IPDI, DTDA and catalyst dibutyltin dilaurate were added to another reactor, the molar ratio of hydroxyl groups in the cashew phenol-based benzoxazine resin, amino groups in the DTDA and -NCO groups in the IPDI was 0.4:0.6:1.1, the amount of catalyst added was 1% of the total mass of the reactants, the reaction temperature was 60°C, and the reaction time was 5h, to obtain cashew phenol-based polyurethane;

[0068] (4) The obtained cashew phenol-based polyurethane and ZIF-8 nanoparticles loaded with corrosion inhibitor methionine were added to tetrahydrofuran, the mass-volume ratio of cashew phenol-based polyurethane to tetrahydrofuran was 0.1g:5mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor was 80% of the mass of the resin, and ultrasonic dispersion was carried out for 20min, to obtain a superhydrophobic coating dispersion;

[0069] (5) The superhydrophobic coating dispersion was uniformly sprayed on the metal substrate, the spraying distance was 15cm, and the spraying pressure was 0.2MPa, to obtain a metal substrate coated with the coating, and then the metal substrate coated with the coating was placed in an oven for heat curing according to the curing process of curing at 160°C for 2h, curing at 180°C for 2h and curing at 200°C for 2h, to obtain a self-repairing superhydrophobic corrosion-resistant coating.

[0070] Example 10

[0071] Contact angle measurement: DSA100 contact angle measurement instrument (Germany, The contact angle (WCA) and sliding angle (SA) of the coating surface were measured by the Drop Master 3 (Kibron Ltd.) and the volume of the droplet for measuring WCA was 5 μL and the volume of the droplet for measuring SA was 15 μL. Anti-corrosion performance: The electrochemical impedance spectroscopy (EIS) of the sample was measured by CHI660e electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.), and Ag / AgCl electrode, platinum sheet electrode and Q235 steel coated with the coating were used as the reference electrode, counter electrode and working electrode, respectively. The exposed area of the working electrode in the solution was 1 cm 2 Self-repairing efficiency: The self-repairing efficiency was calculated by observing the ratio of the width reduction of the scratch before and after repair using an ICC50W Leica optical microscope. The test results of each example are shown in Table 1.

[0072] Table 1 Main performance indicators of cashew phenol-based polyurethane self-repairing super-hydrophobic anti-corrosion coating of examples 2-9

[0073]

[0074] As can be seen from the data in the table, the bio-based polyurethane super-hydrophobic self-repairing anti-corrosion coating prepared by the present application has excellent super-hydrophobic performance, anti-corrosion performance and self-repairing efficiency, and can be used in the field of metal corrosion protection.

[0075] Example 11

[0076] Sandpaper rubbing test: Place the side of the glass slide coated with the coating downward on the 1200-mesh sandpaper, and place a 100g weight on the glass slide. Push the sample and the weight at a uniform speed in one direction for 10 cm, which is recorded as one rubbing cycle. Measure the WCA and SA values of the coating after each rubbing cycle. Tape peeling test: Stick the tape to the coating and then tear off the tape, which is recorded as one cycle. Measure the WCA value of the coating after every 10 cycles. High temperature resistance test: The high temperature resistance of the coating was studied by placing the coating in an oven at 200℃, and measuring the WCA value of the coating at regular intervals. Acid and alkali resistance test: Drop liquids with pH values of 1, 3, 5, 7, 9, 11 and 13 on the surface of the coating, and measure the WCA value of the coating. The above tests were conducted on Example 3, and the test results are as follows:

[0077] After 30 sandpaper rubbing cycles, the WCA of the coating of Example 3 was 151.9°; after 80 tape peeling cycles, the WCA was 150.6°; after the coating was placed in an oven at 200℃ for 12h, the WCA was 150.4℃; and the WCA of the coating on the surface of the coating with pH values of 1, 3, 5, 7, 9, 11 and 13 were all greater than 150°. The results show that the coating of Example 3 has good mechanical stability and environmental stability.

[0078] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification according to the spirit and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A method for preparing a bio-based polyurethane self-healing superhydrophobic anticorrosive liquid, characterized in that... Includes the following steps: (1) Add cashew nut shellac, β-mercaptoethanol, Irgacure-184 and catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene DBU to the reactor. The molar ratio of cashew nut shellac and β-mercaptoethanol is 1:(6~12). Irgacure-184 accounts for 0.5~3% of the total mass of the reactants, and catalyst DBU accounts for 0.5~2% of the total mass of the reactants. Then, heat the reactor to 80~100 °C under ultraviolet light and react for 8~24 h to obtain cashew nut shellac polyol. (2) Add cashew nut shellac polyol, paraformaldehyde and aminopropyl-terminated polydimethylsiloxane to the reactor. The molar ratio of cashew nut shellac polyol, aminopropyl-terminated polydimethylsiloxane and paraformaldehyde is 2:1:(4~10). Heat the reactor to 90~110 °C and react for 8~12 h. h, to obtain cashew phenol-based benzoxazine resin; (3) cashew phenol-based benzoxazine resin, isophorone diisocyanate (IPDI), bis(2-aminophenyl) disulfide and catalyst are added to another reactor, wherein the molar ratio of hydroxyl groups in cashew phenol-based benzoxazine resin, amino groups in bis(2-aminophenyl) disulfide and -NCO groups in IPDI is (0.9~0.1):(0.1~0.9):(1~1.1), and the amount of catalyst added is 0.5~2% of the total mass of reactants. The reactor is heated to 60~80 °C and reacted for 4~8 h to obtain cashew phenol-based polyurethane; (4) cashew phenol-based polyurethane obtained in step (3) and ZIF-8 nanoparticles loaded with corrosion inhibitor are added to an organic solvent, wherein the mass-volume ratio of cashew phenol-based polyurethane to organic solvent is (0.1~0.5) g:10 g. mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor is 60~100% of the mass of cashew phenol-based polyurethane, and after ultrasonic dispersion for 15~30 min, a bio-based polyurethane self-healing superhydrophobic anticorrosive liquid is obtained.

2. The preparation method of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 1, characterized in that, In step (1), the molar ratio of cashew phenol and β-mercaptoethanol is 1:10, Irgacure-184 is 1% of the total mass of reactants, and the catalyst DBU is 1% of the total mass of reactants.

3. The preparation method of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 1, characterized in that, The molar ratio of cashew phenol polyol, aminopropyl-terminated polydimethylsiloxane and paraformaldehyde in step (2) is 2:1:

6.

4. The preparation method of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 1, characterized in that, The catalyst mentioned in step (3) is at least one of dibutyltin dilaurate and 1,4-diazabicyclo[2.2.2]octane, and the amount of catalyst used is 1% of the total mass of the reactants.

5. The preparation method of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 1, characterized in that, The corrosion inhibitor mentioned in step (4) is at least one of methionine, histidine, arginine and glycine, the organic solvent is at least one of butanone, ethyl acetate and tetrahydrofuran, the mass-volume ratio of cashew phenol-based polyurethane to organic solvent is 0.1 g: 5 mL, the mass of ZIF-8 nanoparticles loaded with corrosion inhibitor is 60% of the mass of cashew phenol-based polyurethane, and the ultrasonic dispersion time is 20 min.

6. The preparation method of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 1, characterized in that, The ZIF-8 nanoparticles loaded with corrosion inhibitor described in step (4) have a particle size of 100~800nm. The synthesis method is to disperse ZIF-8 nanoparticles, corrosion inhibitor, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP) in distilled water, wherein the ratio of ZIF-8, corrosion inhibitor, EDC, DMAP and distilled water is 0.5 g:0.3 g:0.01 g:0.01 g:50 mL. The mixture is then reacted at 80~100 ℃ for 2~6 h. After the reaction is completed, the precipitate is collected by centrifugation, washed with distilled water, and dried in a vacuum drying oven at 60~100 ℃ for 2~24 h.

7. The bio-based polyurethane self-healing superhydrophobic anticorrosive liquid prepared by any one of the methods described in claims 1-6.

8. The application of the bio-based polyurethane self-healing superhydrophobic anticorrosive liquid according to claim 7 in the preparation of metal anticorrosive coatings.

9. The application according to claim 8, characterized in that, Bio-based polyurethane self-healing superhydrophobic anti-corrosion liquid was uniformly sprayed onto a metal substrate at a distance of 10-20 cm and a pressure of 0.2 MPa. The metal substrate coated with the coating was then thermo-cured to obtain a self-healing superhydrophobic anti-corrosion coating.

10. The application according to claim 9, characterized in that, The spraying distance is 15 cm, and the curing process is to cure at 160℃ for 2 hours, 180℃ for 2 hours, and 200℃ for 2 hours in sequence.

Images