Nanometer reinforcing agent of modified epoxy powder coating and preparation method of nanometer reinforcing agent

Abstract

The invention discloses a nano reinforcing agent for a modified epoxy powder coating and a preparation method of the nano reinforcing agent, and relates to the technical field of coating materials. According to the invention, through a core-shell-dendritic hybrid structure, different core materials are matched with a shell layer material, and chemical bond directional connection is adopted, so that the nano filler is uniformly dispersed, the problem of agglomeration of a traditional nano material is solved, and meanwhile, high thermal conductivity and antistatic synergism and efficient self-repairing capability are achieved, and a better electrostatic spraying effect is achieved; by adding the nano reinforcing agent with high strength and rigidity, the hardness, impact resistance and wear resistance of the coating can be remarkably improved, so that the service life of the coating is prolonged, and the stability of the coating is improved; due to the design of the nano reinforcing agent and surface functionalization treatment, the hydrophobicity and chemical stability of the coating can be improved, permeation of water and chemical substances is effectively prevented, the corrosion resistance of the coating is enhanced, and the service life of the coating is prolonged.

Description

Technical Field

[0001] The invention relates to a nano-enhancer for modified epoxy powder coating and a preparation method thereof, belonging to the technical field of coating materials. Background Art

[0002] Traditional nano-coating materials often suffer from poor wear resistance, limited corrosion resistance, and difficulty repairing. These coatings are particularly susceptible to failure when used in high-temperature, high-humidity, or harsh environments. Therefore, developing high-performance coatings with enhanced self-healing capabilities, higher electrical and thermal conductivity, and improved weather resistance has become a key issue in the current development of coating technology.

[0003] The existing technology has the following significant defects:

[0004] 1. Poor dispersion of nanofillers: Traditional nano-reinforcements SiO2 and TiO2 are easy to agglomerate in the resin matrix due to their high surface energy, resulting in stress concentration points in the coating, reducing adhesion and impact resistance;

[0005] 2. Limitations of single functionality: Existing modification technologies often focus on improving a single performance, but this sacrifices the coating's self-healing ability. Some technologies achieve self-healing by encapsulating repair agents in microcapsules, but the uncontrollable capsule rupture rate results in a repair efficiency of less than 60%.

[0006] 3. High energy consumption for curing: Conventional epoxy powder needs to be cured at a high temperature of over 180°C for 15 to 20 minutes, which not only increases energy consumption but also easily causes deformation of heat-sensitive substrates.

[0007] 4. Insufficient adaptability of electrostatic spraying: the resistivity of traditional epoxy powder is as high as 10 12 -10 13 Ω·cm, resulting in a powder application rate of less than 70%, and coating leaks are likely to occur on the edges of complex workpieces.

[0008] Therefore, a new solution to the above problems needs to be proposed. Summary of the Invention

[0009] The object of the present invention is to provide a nano-reinforcement agent for modified epoxy powder coating and a preparation method thereof, so as to solve the problems raised in the background technology.

[0010] To achieve the above objectives, the present invention provides the following technical solutions: a nano-reinforcer for modified epoxy powder coatings and a preparation method thereof, wherein the nano-reinforcer for modified epoxy powder coatings includes but is not limited to BN@GQDs core-shell structure nano-reinforcers, MXene / carbon nanotube core-shell system nano-reinforcers, and molybdenum disulfide / black phosphorus quantum dot composite system nano-reinforcers;

[0011] The BN@GQDs core-shell structure nano-enhancer, MXene / carbon nanotube core-shell system nano-enhancer and molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancer all include a core material, a shell material, an interface modifier and a dispersion medium.

[0012] Preferably, the core material of the BN@GQDs core-shell structure nano-enhancer is hexagonal boron nitride nanosheets, i.e. h-BN, and the hexagonal boron nitride nanosheets are 50nm-100nm;

[0013] The shell material of the BN@GQDs core-shell structure nano-enhancer is amino-functionalized graphene quantum dots, i.e., NH2-GQDs, and the amino-functionalized graphene quantum dots are 3nm-5nm;

[0014] The interface modifier of the BN@GQDs core-shell structure nano-enhancer is furanpropyltrimethoxysilane, namely FPTMS;

[0015] The dispersion medium of the BN@GQDs core-shell structure nano-enhancer is epoxy acrylate prepolymer, and the molecular weight of the epoxy acrylate prepolymer is 2000-3000.

[0016] Preferably, the core material of the MXene / carbon nanotube core-shell system nanoreinforcer is two-dimensional titanium carbide, i.e. Ti3C2T x MXene, wherein the thickness of the two-dimensional titanium carbide is 1 nm to 5 nm;

[0017] The shell material of the MXene / carbon nanotube core-shell system nanoreinforcer is amino-modified multi-walled carbon nanotubes, i.e., NH2-MWCNTs, and the diameter of the amino-modified multi-walled carbon nanotubes is 10nm-20nm;

[0018] The dynamic bond modifier of the MXene / carbon nanotube core-shell system nanoreinforcer is a disulfide bond functionalized silane coupling agent;

[0019] The photothermal conversion material of the MXene / carbon nanotube core-shell system nanoenhancer is gold nanorods, i.e., AuNRs, with an aspect ratio of 4:1 and an absorption peak of 808 nm.

[0020] Preferably, the core material of the molybdenum disulfide / black phosphorus quantum dot composite nano-enhancer is layered molybdenum disulfide, i.e., MoS2, with a layer number of <5 and a lateral size of 200 nm;

[0021] The shell material of the MoS2 / black phosphorus quantum dot composite nano-enhancer is carboxylated black phosphorus quantum dots, i.e. COOH-BPQDs, with a size of 2-3 nm.

[0022] The dynamic bond modifier is an acylhydrazone bond functionalized polymer;

[0023] The photothermal conversion material is tungsten oxide nanowires, namely WO3-x, with oxygen vacancies regulated and an absorption peak of 980nm.

[0024] The preparation method of the BN@GQDs core-shell structure nano-enhancer comprises at least the following steps:

[0025] Step 1: Preparation of BN@GQDs core-shell structure;

[0026] h-BN nanosheets were dispersed in NMP and sonicated for 2 h;

[0027] GQDs were added at a mass ratio of h-BN:NH2-GQDs = 1:0.2 and stirred at 80°C for 6 h, where they self-assembled into a core-shell structure through π-π stacking and hydrogen bonding.

[0028] After centrifugal washing, vacuum drying was performed;

[0029] Step 2: dynamic covalent bond surface modification;

[0030] BN@GQDs and FPTMS were refluxed in ethanol at a mass ratio of 10:1 for 4 h to introduce furan groups;

[0031] Add epoxy acrylate prepolymer and carry out graft polymerization at 80°C to form a pre-dispersed masterbatch;

[0032] Step 3: Compounding the reinforcing agent with the epoxy resin;

[0033] Mix the masterbatch with bisphenol A epoxy resin and curing agent in a ratio of 10:85:5;

[0034] The mixture is melt-blended in a twin-screw extruder at a temperature of 110-130°C and crushed into powder with a particle size of 30-50 μm.

[0035] The MXene / carbon nanotube core-shell system nano-enhancer comprises at least the following steps:

[0036] Step 1: Preparation of MXene nanosheets;

[0037] Ti3AlC2MAX phase ceramic powder is used as raw material;

[0038] Etching, 1g Ti3AlC2 powder was immersed in 20mL40% hydrofluoric acid, stirred at 40℃ for 24h, centrifuged and washed until pH>6, and freeze-dried to obtain multilayer Ti3C2T x MXene;

[0039] For exfoliation, MXene was dispersed in DMSO at 10 mg / mL and sonicated for 2 h, followed by centrifugation to collect the monolayer MXene colloidal solution;

[0040] Step 2: Amino-functionalized CNTs grafting;

[0041] CNTs acidification, multi-walled carbon nanotubes were immersed in mixed acid, H2SO4:HNO3=3:1, 70℃ reflux for 4h, introducing -COOH groups;

[0042] Amino-functionalization, acidified CNTs were reacted with ethylenediamine under EDC / NHS catalysis, 60℃ for 12h, obtaining NH2-MWCNTs;

[0043] Step 3: MXene@CNTs self-assembly;

[0044] Electrostatic adsorption, MXene colloid was mixed with NH2-MWCNTs according to the mass ratio of 1:0.3, adjusting the pH value to 9, then stirring at 50℃ for 8h;

[0045] Then centrifugal washing, vacuum drying to obtain MXene@CNTs core-shell structure;

[0046] Step 4: Bis-sulfur bond silane coupling agent grafting;

[0047] MXene@CNTs was refluxed with Bis[3-(triethoxysilyl)propyl]tetrasulfide according to the mass ratio of 10:1 in toluene for 6h, centrifugal to remove unreacted substances, ethanol washing 3 times;

[0048] Step 5: Gold nanorod loading;

[0049] Seed method to synthesize AuNRs:

[0050] Preparation of gold seed solution, HAuCl4 mixed with CTAB, adding NaBH4 fast stirring;

[0051] Growth solution, HAuCl4+AgNO3+ascorbic acid in CTAB, adding seed solution, standing for 12h;

[0052] Loading process, Au NRs was ultrasonic treated with modified MXene@CNTs according to the mass ratio of 1:20 under PVP protection for 1h, centrifugal to collect the composite;

[0053] Step 6: Pre-dispersion master batch preparation;

[0054] Solution blending, MXene@CNTs-Au composite was dissolved in tetrahydrofuran with bisphenol F type epoxy resin, ultrasonic dispersion;

[0055] Solvent removal, rotary evaporation to remove THF, obtaining nano-reinforcing agent master batch.

[0056] The preparation method of the molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancing agent at least comprises the following steps:

[0057] Step 1: MoS2 nanosheet exfoliation;

[0058] By using a lithium intercalation method, 1g of MoS2 powder is immersed in 20mL of n-butyllithium solution, and reacts for 48h under argon protection, and after centrifugal washing, is dispersed in deionized water, and ultrasonic treatment is performed for 4h to obtain a monolayer MoS2 dispersion solution;

[0059] Step 2: BPQDs preparation and compounding;

[0060] The BPQDs are prepared by low-temperature ball milling of a black phosphorus block in NMP, the temperature is-20 DEG C, the pressure is 300rpm, 12h, and the supernatant is collected by centrifugation;

[0061] Solvent thermal compounding, the MoS2 dispersion solution and the BPQDs are mixed in DMF according to a mass ratio of 1:0.5, and hydrothermal reaction is performed at 180 DEG C for 12h to form a MoS2@BPQDs heterojunction;

[0062] Step 3: Dynamic acylhydrazone bond construction;

[0063] Benzaldehyde grafting, the MoS2@BPQDs and 4-formylbenzoic acid are reacted according to a mass ratio of 10:1 under the catalysis of DCC / DMAP for 8h, and the temperature is controlled at 60 DEG C to introduce an aldehyde group;

[0064] Hydrazide group reaction, hexanedioic acid dihydrazide is added in a molar ratio of 1:1.2, and reaction is performed at 60 DEG C for 6h to form a dynamic acylhydrazone bond;

[0065] Step 4: WO3-x nanowire synthesis and loading;

[0066] Hydrothermal synthesis, Na2WO4.2H2O is mixed with HCl, and hydrothermal reaction is performed at 180 DEG C for 24h to obtain WO3-x nanowires;

[0067] Covalent connection, WO3-x and MoS2@BPQDs are reacted at 80 DEG C for 4h under APTES modification;

[0068] Step 5: The MoS2@BPQDs-WO3 composite, a phenolic aldehyde epoxy resin, an acid anhydride curing agent and a leveling agent are mixed to prepare a powder, and a molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancing agent is obtained.

[0069] Compared with the prior art, the molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancing agent has the following beneficial effects:

[0070] 1. The present invention adopts a core-shell-branched hybrid structure, combines different core materials with shell materials, and is directional connected by chemical bonds. The nanofillers are evenly dispersed, thereby solving the agglomeration problem of traditional nanomaterials. At the same time, it achieves high thermal conductivity and antistatic synergy, as well as efficient self-repairing ability, and achieves better electrostatic spraying effect.

[0071] 2. Enhanced mechanical properties: By adding nano-reinforcements with high strength and stiffness, the hardness, impact resistance and wear resistance of the coating can be significantly improved, thereby enhancing the service life and stability of the coating.

[0072] 3. Excellent corrosion resistance and oxidation resistance: Through the design of nano-enhancers, surface functionalization treatment can improve the hydrophobicity and chemical stability of the coating, effectively prevent the penetration of moisture and chemicals, enhance the corrosion resistance of the coating, and extend its service life.

[0073] 4. Good photothermal conversion performance: By introducing photothermal conversion materials, nano-enhancers can improve the photothermal response ability of the coating and expand its application potential in environmental protection, energy absorption and conversion and other fields.

[0074] 5. Improve thermal stability: The design of nano-enhancer can effectively improve the thermal stability of the coating, especially for long-term use in high temperature environment, and has good thermal stability and anti-thermal aging performance.

[0075] 6. Improved interfacial adhesion: Through functional treatment of the surface of the nano-reinforcer with an interfacial modifier, the interfacial adhesion between the nano-reinforcer and the epoxy resin matrix is ​​enhanced, thereby improving the overall adhesion and durability of the coating.

[0076] 7. Environmental protection and high efficiency: The use of nano-enhancers can improve coating performance while reducing the amount of coating materials used, achieving high efficiency and environmental protection of the coating and meeting the needs of green coating. DETAILED DESCRIPTION

[0077] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0078] Example 1:

[0079] The nano-reinforcement agent of the modified epoxy powder coating in this embodiment is a BN@GQDs core-shell structure nano-reinforcement agent;

[0080] The core material of the BN@GQDs core-shell structure nanoreinforcer is hexagonal boron nitride nanosheets, i.e. h-BN, which are 50-100 nm in size.

[0081] The shell material of the BN@GQDs core-shell structure nano-enhancer is amino-functionalized graphene quantum dots, i.e., NH2-GQDs, and the amino-functionalized graphene quantum dots are 3-5 nm;

[0082] The interface modifier of the BN@GQDs core-shell structure nano-enhancer is furanpropyltrimethoxysilane, namely FPTMS;

[0083] The dispersion medium of the BN@GQDs core-shell structure nano-enhancer is epoxy acrylate prepolymer, and the molecular weight of the epoxy acrylate prepolymer is 2000-3000;

[0084] The electrostatic spraying process of BN@GQDs core-shell structure nanoreinforcement agent was optimized;

[0085] Charge improvement: The GQDs shell reduces the powder resistivity to 10^8Ω·cm, compared to 10^12Ω·cm for traditional epoxy powder, improving electrostatic adsorption efficiency by more than 20%.

[0086] Curing procedure: During the curing stage at 180°C / 15 min, GQDs absorb UV light to generate a local thermal effect that raises the temperature to 50°C, accelerating dynamic bond crosslinking.

[0087] Self-repair verification: After scratching, the scratch was treated at 80℃ / UV365nm for 30 minutes, and the scratch healing rate was >90%.

[0088] The specific electrostatic spraying process is as follows:

[0089] Pre-spraying treatment:

[0090] Substrate pretreatment: phosphating treatment, zinc phosphating solution, film thickness 2~4μm, to improve adhesion.

[0091] Table 1 Comparison of BN@GQDs core-shell structure nanoreinforcement and traditional nano-SiO2 reinforced coating

[0092]

[0093] Structural innovation: The core-shell design combined with dynamic covalent bonds breaks through the limitations of traditional physical blending.

[0094] Process compatibility: Pre-dispersed masterbatch technology is compatible with existing powder production lines and does not require additional equipment.

[0095] Versatility: It simultaneously achieves high thermal conductivity, self-healing, and strong adhesion, making it suitable for harsh environments such as new energy vehicle battery brackets.

[0096] This solution solves the problems of epoxy coating brittleness and difficulty in repair through material design and process innovation, and significantly improves the efficiency of electrostatic spraying, with clear industrial application value.

[0097] Example 2:

[0098] This embodiment proposes a preparation method of a BN@GQDs core-shell structure nano-reinforcer based on the above embodiment 1, which includes at least the following steps:

[0099] Step 1: Preparation of BN@GQDs core-shell structure;

[0100] h-BN nanosheets were dispersed in NMP and sonicated for 2 h;

[0101] GQDs were added at a mass ratio of h-BN:NH2-GQDs = 1:0.2 and stirred at 80°C for 6 h, where they self-assembled into a core-shell structure through π-π stacking and hydrogen bonding.

[0102] After centrifugal washing, vacuum drying was performed;

[0103] Step 2: dynamic covalent bond surface modification;

[0104] BN@GQDs and FPTMS were refluxed in ethanol at a mass ratio of 10:1 for 4 h to introduce furan groups;

[0105] Add epoxy acrylate prepolymer and carry out graft polymerization at 80°C to form a pre-dispersed masterbatch;

[0106] Step 3: Compounding the reinforcing agent with the epoxy resin;

[0107] Mix the masterbatch with bisphenol A epoxy resin E-12 and curing agent dicyandiamide in a ratio of 10:85:5;

[0108] The mixture is melt-blended in a twin-screw extruder at a temperature of 110-130°C and crushed into powder with a particle size of 30-50 μm.

[0109] Spraying parameter optimization:

[0110] Voltage: 60-80kV;

[0111] Spray gun distance: 150~200mm;

[0112] Powder resistivity: 10 6 ~10 7 Ω·cm was regulated by MWCNTs / GQDs;

[0113] Powdering rate: ≥85%;

[0114] Curing procedure:

[0115] Stage 1: 120℃ / 10min pre-gel to avoid sagging;

[0116] Stage 2: 180℃ / 15min main curing, dynamic bond crosslinking;

[0117] Stage 3: NIR irradiation at 808nm for 5min triggers the PDA photothermal effect and repairs microcracks.

[0118] Core-shell structure: Hexagonal boron nitride nanosheets h-BN, 50-100nm, are used as the core, and amino-functionalized graphene quantum dots NH2-GQDs, 3-5nm, are self-assembled through π-π stacking and hydrogen bonding to form a shell, forming a BN@GQDs complex, which solves the problem of nano-agglomeration and improves conductivity;

[0119] Dynamic bond modification uses furanyltrimethoxysilane (FPTMS) to graft the BN@GQDs surface, introducing furan groups that form reversible Diels-Alder bonds with the maleimide groups in the epoxy resin during curing, giving the coating self-healing capabilities.

[0120] The photothermal synergistic layer coats polydopamine on the surface of GQDs, utilizing its near-infrared absorption characteristics of 808nm to trigger a local thermal effect to raise the temperature by 50-80°C, accelerate dynamic bond recombination, and achieve rapid scratch repair.

[0121] Example 3:

[0122] This embodiment proposes a MXene / carbon nanotube (CNTs) core-shell system nanoreinforcement agent;

[0123] The core material is two-dimensional titanium carbide, namely Ti3C2T x MXene, wherein the thickness of the two-dimensional titanium carbide is 1 nm to 5 nm;

[0124] The shell material is amino-modified multi-walled carbon nanotubes, i.e., NH2-MWCNTs, and the diameter of the amino-modified multi-walled carbon nanotubes is 10nm-20nm;

[0125] The dynamic bond modifier is a disulfide functionalized silane coupling agent;

[0126] Photothermal conversion material: gold nanorods, i.e. Au NRs, with an aspect ratio of 4:1 and an absorption peak at 808nm.

[0127] Table 2MXene / CNTs core-shell system

[0128]

[0129]

[0130] Example 4:

[0131] This embodiment proposes a preparation method of a MXene / carbon nanotube (CNTs) core-shell system nanoreinforcement agent based on the above embodiment three;

[0132] Step 1: Preparation of MXene nanosheets;

[0133] Use Ti3AlC2MAX phase ceramic powder with particle size ≤38μm as raw material;

[0134] Etching, 1g Ti3AlC2 powder was immersed in 20mL40% hydrofluoric acid, stirred at 40℃ for 24h, centrifuged and washed until pH>6, and freeze-dried to obtain multilayer Ti3C2T x MXene;

[0135] For exfoliation, MXene was dispersed in DMSO at 10 mg / mL and sonicated for 2 h, followed by centrifugation to collect the monolayer MXene colloidal solution;

[0136] Step 2: grafting of amination-modified CNTs;

[0137] CNTs acidification treatment: immerse multi-walled carbon nanotubes (MWCNTs) in mixed acid (H2SO4:HNO3=3:1) and reflux at 70°C for 4 h to introduce -COOH groups;

[0138] For amino functionalization, acidified CNTs were reacted with ethylenediamine (EDA) in the presence of EDC / NHS at 60 °C for 12 h to obtain NH2-MWCNTs.

[0139] Step 3: MXene@CNTs self-assembly;

[0140] Electrostatic adsorption: 0.1 wt% MXene colloid was mixed with NH2-MWCNTs at a mass ratio of 1:0.3, the pH value was adjusted to 9, and the mixture was stirred at 50 °C for 8 h;

[0141] Then, the MXene@CNTs core-shell structure was obtained by centrifugal washing and vacuum drying;

[0142] Step 4: disulfide bond silane coupling agent grafting;

[0143] MXene@CNTs and Bis[3-(triethoxysilyl)propyl]tetrasulfide were refluxed in toluene at a mass ratio of 10:1 for 6 h, centrifuged to remove unreacted products, and washed with ethanol three times;

[0144] Step 5: gold nanorod loading;

[0145] Synthesis of AuNRs by seed method:

[0146] To prepare the gold seed solution, 0.25 mM HAuCl4 was mixed with 0.1 M CTAB, and 0.01 M NaBH4 was added and stirred rapidly;

[0147] Growth solution, 0.5 mM HAuCl4 + 0.1 mM AgNO3 + 0.8 mM ascorbic acid in 0.1 M CTAB, added with seed solution, and allowed to stand for 12 h;

[0148] In the loading process, Au NRs and modified MXene@CNTs were ultrasonically treated for 1 h under PVP protection at a mass ratio of 1:20, and the complex was collected by centrifugation;

[0149] Step 6: Preparation of pre-dispersed masterbatch;

[0150] Solution blending: MXene@CNTs-Au composite (8 wt%) and bisphenol F epoxy resin (EEW ​​= 750 g / eq) were dissolved in tetrahydrofuran (THF) and ultrasonically dispersed at 500 W for 2 h.

[0151] The solvent was removed and THF was removed by rotary evaporation to obtain the nano-enhancer masterbatch.

[0152] Electrostatic spraying process parameters

[0153] Powder resistivity: 10 4 Ω·cm, MXene conductive network dominated;

[0154] Curing procedure:

[0155] Stage 1: 100°C / 10min pre-curing;

[0156] Stage 2: NIR (808 nm, 2 W / cm 2 ) for 10 min, triggering the photothermal effect of Au NRs to locally heat up to 120°C and activate the recombination of disulfide bonds.

[0157] Technological advantages

[0158] Ultra-high conductivity: MXene intrinsic conductivity is >6000S / cm, and when combined with CNTs to form a three-dimensional conductive network, the resistivity can be reduced to 10 4 Ω·cm;

[0159] Photothermal synergistic enhancement: gold nanorods have a near-infrared absorption efficiency of >90%, with local temperature rise up to 100°C, accelerating dynamic bond recombination;

[0160] Self-repair mechanism: disulfide bonds can be reversibly broken and reassembled under heat / light triggering, with a healing efficiency of >90%.

[0161] Preparation key points

[0162] After fluorination treatment and NH4HF2 etching, the MXene surface forms a core-shell structure with NH2-MWCNTs through electrostatic self-assembly;

[0163] Surface grafting was performed using a silane coupling agent containing a disulfide bond, Bis[3-(triethoxysilyl)propyl]tetrasulfide.

[0164] Gold nanorods were synthesized by seed growth method and loaded on the surface of MXene@CNTs.

[0165] Example five:

[0166] The embodiment provides a molybdenum disulfide (MoS2) / black phosphorus quantum dot (BPQD) composite system nano-enhancing agent.

[0167] The core material of the molybdenum disulfide (MoS2) / black phosphorus quantum dot (BPQD) composite system nano-enhancing agent is layered molybdenum disulfide, i.e., MoS2, the number of layers is less than 5, and the lateral size is 200 nm.

[0168] The shell material of the molybdenum disulfide (MoS2) / black phosphorus quantum dot (BPQD) composite system nano-enhancing agent is carboxylated black phosphorus quantum dots, i.e., COOH-BPQDs, and the size is 2-3 nm.

[0169] The dynamic bond modifier is an acylhydrazone bond functionalized polymer.

[0170] The photo-thermal conversion material is tungsten oxide nanowire, i.e., WO3-x, and the oxygen vacancy is regulated, and the absorption peak is 980 nm.

[0171] Table 3 MoS2 / BPQD composite system

[0172]

[0173] Technical advantages

[0174] Anisotropic thermal conductivity: the in-plane thermal conductivity coefficient of MoS2 reaches 100 W / m·K, and BPQDs enhance the interface heat transfer.

[0175] Wide-spectrum light response: BPQDs can realize full-spectrum photo-thermal conversion through visible light absorption + WO3-x near-infrared absorption.

[0176] pH-responsive self-repair: the acylhydrazone bond can reversibly dissociate in an acidic microenvironment, which is suitable for marine corrosion scenarios.

[0177] Example six:

[0178] The embodiment provides a preparation method of a molybdenum disulfide (MoS2) / black phosphorus quantum dot (BPQD) composite system nano-enhancing agent.

[0179] Step 1: MoS2 nanosheet exfoliation

[0180] Using the lithium intercalation method, 1g of MoS2 powder was immersed in 20mL of n-butyllithium solution and reacted under argon protection for 48h. After centrifugation and washing, it was dispersed in deionized water and ultrasonicated for 4h to obtain a monolayer MoS2 dispersion.

[0181] Step 2: BPQDs preparation and compounding;

[0182] For the preparation of BPQDs, the black phosphorus block was cryo-milled in NMP at −20 °C and 300 rpm for 12 h, and the supernatant was collected by centrifugation.

[0183] Solvothermal compounding: MoS2 dispersion and BPQDs were mixed in DMF at a mass ratio of 1:0.5 and hydrothermally reacted at 180°C for 12 h to form a MoS2@BPQDs heterojunction;

[0184] Step 3: Dynamic acylhydrazone bond construction;

[0185] Benzaldehyde grafting: MoS2@BPQDs and 4-formylbenzoic acid were reacted in a mass ratio of 10:1 under the catalysis of DCC / DMAP for 8 h at a temperature of 60 °C to introduce aldehyde groups;

[0186] For the reaction of hydrazide groups, add adipic acid dihydrazide at a molar ratio of 1:1.2 and react at 60°C for 6 h to form a dynamic acylhydrazone bond;

[0187] Step 4: WO3-x nanowire synthesis and loading;

[0188] Hydrothermal synthesis: Na2WO4·2H2O (0.1 M) was mixed with HCl (pH = 2) and hydrothermaled at 180 °C for 24 h to obtain WO3-x nanowires;

[0189] Covalently linked, WO3-x and MoS2@BPQDs were modified with APTES silane coupling agent and reacted at 80 °C for 4 h;

[0190] Step 5: Mix the MoS2@BPQDs-WO3 complex (10wt%), phenolic epoxy resin (70wt%), anhydride curing agent HHPA, 15wt% and leveling agent BYK-361N, 5wt% to prepare powder and obtain a molybdenum disulfide (MoS2) / black phosphorus quantum dots (BPQDs) composite system nano-enhancer.

[0191] Electrostatic spraying parameters

[0192] Voltage: 70kV, increased to 80kV for complex workpieces;

[0193] Curing trigger:

[0194] Acidic environment pH = 4 or 980nm laser 1.5W / cm 2Irradiation, activation of acylhydrazone bond repair.

[0195] Key points of preparation

[0196] After MoS2 is intercalated and exfoliated by lithium ions, the MoS2 is combined with BPQDs by a solvothermal method DMF at 180 DEG C for 12 hours.

[0197] The polyoxymethylene glycol group is reacted with the hydrazine group to form a dynamic acylhydrazone bond.

[0198] The WO3-x nanowires are synthesized by a hydrothermal method and are covalently connected with the composite.

[0199] Comparing examples one, three and five, refer to the following table 4;

[0200] Table 4 comprehensive comparison

[0201]

[0202] To sum up, the application discloses a nano reinforcing agent for modified epoxy powder coating and a preparation method thereof, and relates to the technical field of coating materials.The core-shell-branched hybrid structure is used in the application, different core materials are matched with shell materials, and the nano fillers are uniformly dispersed through directional connection by chemical bonds, so that the problem of agglomeration of traditional nano materials is solved, high thermal conductivity and antistatic synergy are achieved, and high-efficiency self-repairing capability is achieved, and better electrostatic spraying effect is achieved;the mechanical properties are enhanced: by adding the nano reinforcing agent with high strength and rigidity, the hardness, impact resistance and wear resistance of the coating can be significantly improved, so that the service life and stability of the coating are enhanced;excellent corrosion resistance and oxidation resistance: through the design of the nano reinforcing agent, the surface functionalization treatment can improve the hydrophobicity and chemical stability of the coating, effectively prevent the penetration of water and chemicals, enhance the corrosion resistance of the coating, and prolong the service life of the coating.

[0203] The above is only a further embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can make equivalent replacement or change according to the technical scheme and concept of the application within the scope disclosed by the application, which belongs to the protection scope of the application.

Claims

1. Nano-enhancer for modified epoxy powder coating, characterized by: Including but not limited to BN@GQDs core-shell structure nanoreinforcement agents, MXene / carbon nanotube core-shell system nanoreinforcement agents and molybdenum disulfide / black phosphorus quantum dot composite system nanoreinforcement agents; The BN@GQDs core-shell structure nano-enhancer, MXene / carbon nanotube core-shell system nano-enhancer and molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancer all include a core material, a shell material, an interface modifier and a dispersion medium.

2. The nano-reinforcement agent for modified epoxy powder coating according to claim 1, characterized in that: The core material of the BN@GQDs core-shell structure nano-enhancer is hexagonal boron nitride nanosheets, i.e. h-BN, and the hexagonal boron nitride nanosheets are 50nm-100nm; The shell material of the BN@GQDs core-shell structure nano-enhancer is amino-functionalized graphene quantum dots, i.e., NH2-GQDs, and the amino-functionalized graphene quantum dots are 3nm-5nm; The interface modifier of the BN@GQDs core-shell structure nano-enhancer is furanpropyltrimethoxysilane, namely FPTMS; The dispersion medium of the BN@GQDs core-shell structure nano-enhancer is epoxy acrylate prepolymer, and the molecular weight of the epoxy acrylate prepolymer is 2000-3000.

3. The nano-reinforcement agent for modified epoxy powder coating according to claim 1, characterized in that: The core material of the MXene / carbon nanotube core-shell system nanoreinforcer is two-dimensional titanium carbide, i.e. Ti3C2T x MXene, wherein the thickness of the two-dimensional titanium carbide is 1 nm to 5 nm; The shell material of the MXene / carbon nanotube core-shell system nanoreinforcer is amino-modified multi-walled carbon nanotubes, i.e., NH2-MWCNTs, and the diameter of the amino-modified multi-walled carbon nanotubes is 10nm-20nm; The dynamic bond modifier of the MXene / carbon nanotube core-shell system nanoreinforcer is a disulfide bond functionalized silane coupling agent; The photothermal conversion material of the MXene / carbon nanotube core-shell system nanoenhancer is gold nanorods, i.e., Au NRs, with an aspect ratio of 4:1 and an absorption peak of 808 nm.

4. The nano-reinforcement agent for modified epoxy powder coating according to claim 1, characterized in that: The core material of the MoS2 / BLQD composite nano-enhancer is layered MoS2, i.e., MoS2, with a layer number of <5 and a lateral size of 200 nm. The shell material of the MoS2 / black phosphorus quantum dot composite nano-enhancer is carboxylated black phosphorus quantum dots, i.e. COOH-BPQDs, with a size of 2-3 nm. The dynamic bond modifier is an acylhydrazone bond functionalized polymer; The photothermal conversion material is tungsten oxide nanowires, namely WO3-x, with oxygen vacancies regulated and an absorption peak of 980nm.

5. A method for preparing a nano-reinforcer for modified epoxy powder coating, wherein the nano-reinforcer for modified epoxy powder coating according to claim 2 is characterized in that: At least the following steps are included: Step 1: Preparation of BN@GQDs core-shell structure; h-BN nanosheets were dispersed in NMP and sonicated for 2 h; GQDs were added at a mass ratio of h-BN:NH2-GQDs = 1:0.2 and stirred at 80°C for 6 h, where they self-assembled into a core-shell structure through π-π stacking and hydrogen bonding. After centrifugal washing, vacuum drying was performed; Step 2: dynamic covalent bond surface modification; BN@GQDs and FPTMS were refluxed in ethanol at a mass ratio of 10:1 for 4 h to introduce furan groups; Add epoxy acrylate prepolymer and graft polymerize at 80°C to form a pre-dispersed masterbatch; Step 3: Compounding the reinforcing agent with the epoxy resin; Mix the masterbatch with bisphenol A epoxy resin and curing agent in a ratio of 10:85:5; The mixture is melt-blended in a twin-screw extruder at a temperature of 110-130°C and crushed into powder with a particle size of 30-50 μm.

6. A method for preparing a nano-reinforcer for modified epoxy powder coating, wherein the nano-reinforcer for modified epoxy powder coating according to claim 3 is characterized in that: At least the following steps are included: Step 1: Preparation of MXene nanosheets; Ti3AlC2MAX phase ceramic powder is used as raw material; Etching, 1g Ti3AlC2 powder was immersed in 20mL40% hydrofluoric acid, stirred at 40℃ for 24h, centrifuged and washed until pH>6, and freeze-dried to obtain multilayer Ti3C4T x MXene; For exfoliation, MXene was dispersed in DMSO at 10 mg / mL and sonicated for 2 h, followed by centrifugation to collect the monolayer MXene colloidal solution; Step 2: grafting of amination-modified CNTs; Acidification treatment of CNTs: immerse the multi-walled carbon nanotubes in mixed acid (H2SO4:HNO3=3:1) and reflux at 70℃ for 4h to introduce -COOH groups; For amino functionalization, the acidified CNTs were reacted with ethylenediamine in the presence of EDC / NHS at 60 °C for 12 h to obtain NH2-MWCNTs. Step 3: MXene@CNTs self-assembly; Electrostatic adsorption: MXene colloid and NH2-MWCNTs were mixed at a mass ratio of 1:0.3, the pH value was adjusted to 9, and then stirred at 50 °C for 8 h; Then, the MXene@CNTs core-shell structure was obtained by centrifugal washing and vacuum drying; Step 4: disulfide bond silane coupling agent grafting; MXene@CNTs and Bis[3-(triethoxysilyl)propyl]tetrasulfide were refluxed in toluene at a mass ratio of 10:1 for 6 h, centrifuged to remove unreacted products, and washed with ethanol three times; Step 5: gold nanorod loading; Synthesis of AuNRs by seed method: To prepare the gold seed solution, HAuCl4 was mixed with CTAB and NaBH4 was added and stirred rapidly; Growth solution, HAuCl4+AgNO3+ascorbic acid in CTAB, added with seed solution and allowed to stand for 12 h; In the loading process, Au NRs and modified MXene@CNTs were ultrasonically treated under PVP protection at a mass ratio of 1:20 for 1 h, and the composite was collected by centrifugation; Step 6: Preparation of pre-dispersed masterbatch; Solution blending: MXene@CNTs-Au composite and bisphenol F epoxy resin were dissolved in tetrahydrofuran and ultrasonically dispersed; The solvent was removed and THF was removed by rotary evaporation to obtain the nano-enhancer masterbatch.

7. A method for preparing a nano-reinforcer for modified epoxy powder coating, wherein the nano-reinforcer for modified epoxy powder coating according to claim 4 is characterized in that: At least the following steps are included: Step 1: MoS2 nanosheet exfoliation; Using the lithium intercalation method, 1g of MoS2 powder was immersed in 20mL of n-butyllithium solution and reacted under argon protection for 48h. After centrifugal washing, it was dispersed in deionized water and ultrasonicated for 4h to obtain a monolayer MoS2 dispersion. Step 2: BPQDs preparation and compounding; For the preparation of BPQDs, the black phosphorus block was cryo-milled in NMP at −20 °C and 300 rpm for 12 h, and the supernatant was collected by centrifugation. Solvothermal compounding: MoS2 dispersion and BPQDs were mixed in DMF at a mass ratio of 1:0.5 and hydrothermally reacted at 180°C for 12 h to form a MoS2@BPQDs heterojunction; Step 3: Dynamic acylhydrazone bond construction; Benzaldehyde grafting: MoS2@BPQDs and 4-formylbenzoic acid were reacted in a mass ratio of 10:1 under the catalysis of DCC / DMAP for 8 h at a temperature of 60 °C to introduce aldehyde groups; For the reaction of hydrazide groups, add adipic acid dihydrazide at a molar ratio of 1:1.2 and react at 60°C for 6 h to form a dynamic acylhydrazone bond; Step 4: WO3-x nanowire synthesis and loading; Hydrothermal synthesis: Na2WO4·2H2O was mixed with HCl and hydrothermal heated at 180℃ for 24h to obtain WO3-x nanowires; Covalently linked, WO3-x and MoS2@BPQDs were reacted at 80 °C for 4 h under APTES modification; Step 5: The MoS2@BPQDs-WO3 complex, phenolic epoxy resin, anhydride curing agent and leveling agent are mixed to prepare powder to obtain a molybdenum disulfide / black phosphorus quantum dot composite system nano-enhancer.

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