Magnetic nanoparticle as photocuring co-initiator as well as preparation method and application of magnetic nanoparticle

Abstract

The invention discloses a magnetic nanoparticle as a photocuring co-initiator and a preparation method and application thereof, and belongs to the technical field of photocuring co-initiators. The preparation method comprises the following steps: coating the surface of a Fe3O4 nanoparticle with a layer of MoS2, grafting PEI through a chemical bond, forming a carrier on the surface of the Fe3O4 (at) MoS2 magnetic nanoparticle, forming active free radicals with the Fe3O4 (at) MoS2 magnetic nanoparticle in a photo-reduction process by using PEI as a coupling agent, and reducing all Ag nanoparticles to the surface of the particle carrier by reducing noble metal salt AgNO3, so as to prepare the Fe3O4 (at) MoS2 (at) PEI (at) Ag magnetic nanoparticle. The magnetic nanoparticles are used as a photocuring co-initiator. The Fe3O4 (at) MoS2 (at) PEI (at) Ag magnetic nanoparticle provided by the invention has a small-size effect and superparamagnetism, can increase the concentration of a surface initiator in a photocuring process, and improves the photopolymerization efficiency.

Description

Technical Field

[0001] The present invention relates to a magnetic nanoparticle as a photoinitiator co - initiator, its preparation method and application, specifically to promote the reaction of a photocuring system and optimize the photocuring resin system by using the corrosion - resistance and antibacterial properties of magnetic nanoparticles. In particular, it relates to an Fe3O4@MoS2@PEI@Ag magnetic nanoparticle as a photoinitiator co - initiator, its preparation method and application, belonging to the technical field of photoinitiator co - initiators. Background Art

[0002] Light, as the main energy source in nature, affects human life in many aspects such as photosynthesis of plants, light reflection, light therapy for treating diseases, energy converted from sunlight, industrial production, and machinery manufacturing. The two directions of photopolymerization and photoreduction in ultraviolet light research have received continuous attention.

[0003] Due to its high efficiency, energy conservation, environmental protection and other characteristics, the photocuring technology has been widely used in the fields of coatings, electronic packaging, 3D printing and biomedical materials. However, with the complexity of application scenarios and the diversification of functional requirements, the existing technology faces the following key bottlenecks.

[0004] 1. Low photo - initiation efficiency and noble metal waste problem:

[0005] The narrow photo - response range of traditional photoinitiators: Existing photoinitiators (such as benzoin ethers) mainly rely on ultraviolet light (300 nm) and have low utilization rate of visible light. For example, CN117258785A discloses an Ag / TiO2 composite photocatalyst, in which the TiO2 support only responds to ultraviolet light (absorption threshold 380 nm), and the loading amount of Ag nanoparticles is as high as 4.8 wt%, which is easy to cause a decrease in activity due to aggregation. The photo - response range of the present invention is 300 - 800 nm, with a wide photo - response range and high light utilization rate.

[0006] 2. Difficulty in recovering nano - catalysts and environmental pollution risk problem:

[0007] The separation problem of small - sized nanoparticles: Traditional separation methods (such as centrifugation and filtration) are inefficient for particles smaller than 100 nm.

[0008] 3. Insufficient functional integration and poor scene adaptability, with a single - function - dominated design problem:

[0009] Existing technologies mostly focus on optimizing single performance and are difficult to meet the requirements of complex scenarios. For example, CN117941679A provides a silver-loaded glass antibacterial agent, its transparent antibacterial resin products and articles, which have high antibacterial performance but are extremely corrosion-resistant. Another example is the Fe3O4@SiO2 core-shell structure, which can achieve magnetic recovery, but the SiO2 shell layer is inert and there is no improvement in the photoinitiation efficiency (curing time is 180 seconds), while the curing time of the present invention is 150 seconds (single layer, thickness <100μm). Summary of the Invention

[0010] The technical problem to be solved by the present invention is that the present invention provides a magnetic nanoparticle as a photo-curing co-initiator. The present invention utilizes the particle dispersion in the magnetic nanoparticles to optimize the antibacterial and corrosion resistance of the coating; it can also solve the common oxygen inhibition polymerization and the aggregation phenomenon of Ag nanoparticles during the curing process, reduce the waste of precious metal particles, and improve the curing rate.

[0011] Free radicals are a process of the curing reaction. Only when free radicals are generated can the polymerization reaction continue. The presence of oxygen will compete with the polymerization reaction of free radicals and consume free radicals, preventing the reaction from proceeding, forming an oxygen inhibition polymerization effect. Oxygen is harmful and free radicals are beneficial. During photo-curing in air, the oxygen inhibition polymerization often leads to the situation where the bottom layer of the coating is cured and the surface is uncured and sticky. The present invention can solve the common oxygen inhibition polymerization phenomenon during the curing process, with a fast curing time and complete curing.

[0012] Due to their unique physical and chemical properties, noble metal nanoparticles can be applied in the fields of optics, catalysts, biomedicine, sensors, electrochemistry, etc. Especially the use of noble metal nanoparticles as catalysts is closely related to the development of the human social environment. However, due to the high surface energy of noble metal nanoparticles, they are not easy to recycle and are prone to aggregation, and these phenomena have all caused a reduction in their catalytic efficiency. Therefore, it is a research direction to require a suitable carrier and be able to solve the waste phenomenon and aggregation phenomenon of noble metal nanoparticle catalysts.

[0013] At the same time, the present invention provides a preparation method of a magnetic nanoparticle as a photo-curing co-initiator.

[0014] At the same time, the present invention provides an application of a magnetic nanoparticle as a photo-curing co-initiator.

[0015] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0016] A kind of magnetic nanoparticles as a photoinitiator, especially Fe3O4@MoS2@PEI@Ag magnetic nanoparticles as a photoinitiator. A layer of molybdenum disulfide (MoS2) is coated on the surface of iron oxide nanoparticles (Fe3O4NPs), and then polyetherimide (PEI) is grafted through chemical bonds to form a magnetic nanoparticle carrier. The magnetic nanoparticle carrier is used to form active free radicals during the photoreduction process to reduce the precious metal salt AgNO3, and Fe3O4@MoS2@PEI@AgNPs magnetic nanoparticle photoinitiator is prepared.

[0017] Preferably, the Fe3O4@MoS2@PEI@Ag magnetic nanoparticles have a particle size of 50-100 nm, a specific surface area between 90 m 2 / g and 180 m 2 / g, and have small size effect, superparamagnetism, strong catalytic performance, good dispersibility and binding ability with resin.

[0018] Preferably, the preparation process of the Fe3O4@MoS2@PEI@Ag magnetic nanoparticles is as follows:

[0019] (1) Preparation of Fe3O4 nanoparticles (Fe3O4NPs): Using NH3·H2O with a mass concentration of 27%, FeCl2·4H2O and FeCl3·6H2O as reaction materials, adding FeCl3·6H2O and FeCl2·4H2O into the reaction flask and mixing them with distilled water to form a solution. Raise the temperature for reaction. After complete dissolution, adjust the pH by dropping ammonia water at a rate of 10-15 drops per minute, continue the reaction for about 1 h, let it stand and cool to room temperature. The synthesized product is first washed with distilled water, centrifuged, then washed with ethanol, centrifuged again, and dried by heating to obtain the product Fe3O4 nanoparticles.

[0020] (2) Preparation of Fe3O4@MoS2: Add MoS2 microspheres with a particle size range of 100-140 nm and Fe3O4NPs into distilled water, and perform ultrasonic dispersion at a temperature of 30 °C for 20 min with an ultrasonic wave of 30 Hz and a power of 120 W. Transfer the ultrasonically dispersed solution to a closed reaction vessel (such as a reaction kettle) and heat it for reaction for 12-24 h; then let it stand for 6-10 h for natural cooling; collect the sedimented Fe3O4 with a strong magnet (preferably a strong magnet of model H40, specifically a sintered neodymium iron boron strong magnet with a magnetic attraction strength of 1000-3000 gauss and a magnetic field strength of 1000-5000 gauss), wash it 1-3 times with distilled water and ethanol respectively, and store it for later use after drying.

[0021] Preferably, the model of the MoS2 microspheres is M888682.

[0022] Preferably, a strong magnet of model H40, specifically a sintered neodymium iron boron strong magnet with a size of 50*20*10 mm, has a magnetic attraction strength of 2000-3000 Gauss and a magnetic field strength of 3000-5000 Gauss.

[0023] (3) Preparation of Fe3O4@MoS2@PEI: Dissolve the synthesized Fe3O4@MoS2 in step (2) in a toluene solution, stir vigorously at a speed of 1000 r / min for 40 minutes, dropwise add γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) into the solution, and stir at a speed of 300 r / min at room temperature for 25 minutes. Filter out the sediment through a filter, and then wash it with ethanol and water to obtain KH560-modified Fe3O4@MoS2 nanoparticles; add the KH560-modified magnetic Fe3O4@MoS2 nanoparticles to an aqueous solution of polyethyleneimine (PEI), and mechanically stir at a speed of 200 r / min at room temperature for 18-20 h. After the reaction, collect the product with a strong magnet and wash it 1-3 times with water and ethanol each to obtain Fe3O4@MoS2@PEI nanoparticles.

[0024] The dosage of the PEI aqueous solution is 2-5 times the mass of the KH560-modified magnetic Fe3O4@MoS2 nanoparticles, and the density of the prepared PEI aqueous solution is basically close to 1.

[0025] Preferably, a reverse osmosis filter element is provided inside the filter, and the filtration accuracy of the reverse osmosis filter element can reach below 0.0001 microns.

[0026] (4) Preparation of silver-coated Fe3O4@MoS2@PEI magnetic nanoparticles: Dissolve AgNO3 in a 95% ethanol solution by ultrasonic treatment (such as ultrasonic power of 200 W), mix the ethanol solution containing Fe3O4@MoS2@PEI magnetic microspheres with the ethanol solution of AgNO3 according to a volume ratio of 1:2 to obtain a mixed solution A; heat the mixed solution A in a water bath and stir at a speed of 300 r / min for 0.5-1 h to obtain a mixed solution B; dropwise add the ethanol solution of n-butylamine into the mixed solution B to obtain a mixed solution C, keep the water bath temperature unchanged, and continue to mechanically stir the mixed solution C at a speed of 150-300 r / min for about 3 h; separate the product with a magnet, wash it 1-3 times with absolute ethanol, and then dry it under vacuum to obtain the final product

[0027] Fe3O4@MoS2@PEI@Ag magnetic nanoparticles.

[0028] Preferably, in step (1) of the preparation process, the mass ratio of FeCl3·6H2O, FeCl2·4H2O to the solvent distilled water is (11 - 22):(8 - 16):(4 - 8). Further preferably, the mass ratio of FeCl3·6H2O, FeCl2·4H2O to the solvent distilled water is 11:8:4. Raise the temperature to 90°C - 95°C, adjust the pH to 9.0, continue the reaction for about 1 h, cool and wash, then centrifuge at a high speed of 400 - 8000 r / min for 5 - 6 min, and dry the product at 80°C - 90°C.

[0029] Preferably, in step (2) of the preparation process, the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is (2 - 4):1:(60 - 120). Further preferably, the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 2:1:60. The reaction temperature is 180°C - 190°C, the reaction time is 12 - 24 h, and the drying temperature in the oven after washing is 50°C - 60°C.

[0030] Preferably, in step (3) of the preparation process, the mass ratio of toluene solution to Fe3O4@MoS2 is 52:1, and the volume ratio of toluene solution to KH560 is 15:1. The concentration of the used PEI solution is 10 - 20 mg / mL, and the stirring reaction time is 18 h - 20 h.

[0031] Preferably, in step (4) of the preparation process, in the 95% ethanol solution containing AgNO3, the mass ratio of AgNO3 to the 95% ethanol solution is (1 - 3):33. Further preferably, the mass ratio of AgNO3 to the 95% ethanol solution is 1:33. In the ethanol solution containing Fe3O4@MoS2@PEI magnetic microspheres, the mass ratio of Fe3O4@MoS2@PEI to the ethanol solvent is 1:60. After mixing, the water bath temperature is (50 ± 1)°C, the concentration of the ethanol solution of n-butylamine is 0.015 g / mL, the volume ratio of the ethanol solution of n-butylamine to the mixed solution B is 1:20, the vacuum drying temperature is 60°C, and the drying time is 3 h - 4 h.

[0032] Throughout the text, the ethanol is 95% ethanol.

[0033] Preferably, the magnetic nanoparticles can be used in the field of 300 - 800 nm photocuring. As a photocuring co-initiator, the dosage is (0.02 - 3)% of the total amount of the photocuring resin, and it acts synergistically with the main initiator and other additives to improve the curing efficiency and product performance.

[0034] A typical UV system formulation is as follows:

[0035] Mixing: Add 45 g of polyurethane acrylate oligomer (Sartomer CN9010), 40 g of acrylate monomer (trimethylolpropane triacrylate), 1 g of magnetic nanoparticles (Fe3O4@MoS2@PEI@Ag magnetic nanoparticles), and 5 g of additives [1 g of leveling agent (such as BYK-333), 1 g of defoaming agent (such as BYK-066N), 3 g of adhesion promoter (such as Silquest A-174)] into a stirring container, and stir at a speed of 300 r / min for 30 minutes to fully mix and homogenize all components.

[0036] Adding photoinitiator: Under stirring, slowly add 3 g (0.3 - 0.6 g per minute) of photoinitiator (1-hydroxycyclohexyl phenyl ketone), and continue stirring for 20 minutes to ensure that the photoinitiator is completely dissolved and evenly dispersed.

[0037] Coating: Use a suitable coating method (such as scraping, spraying, etc.) to evenly coat the prepared UV resin system on the stainless steel substrate.

[0038] Curing: Place the coated stainless steel substrate under a 500W 365nm ultraviolet lamp and irradiate for 150s to cure the coating.

[0039] Post-treatment: After curing, place the product at room temperature for 24 - 48 hours to further stabilize its performance.

[0040] For the above UV system formulation, without adding magnetic nanoparticles (Fe3O4@MoS2@PEI@Ag magnetic nanoparticles), and the rest is the same as above. Under a 500W, 365nm ultraviolet lamp, the conventional curing time is 300 seconds.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) The product of the present invention exhibits significant co-initiating and anti-oxidative inhibition effects, improving the polymerization efficiency of the photocuring resin system. On the one hand, during the photopolymerization process, PEI, as the carrier of the magnetic nanoparticle co-initiator, can reduce Ag nanoparticles to the surface of the carrier additive, and act together with the initiator to generate free radicals. On the other hand, Fe3O4@MoS2@PEI@Ag magnetic nanoparticles have superparamagnetism, which can cause them to have an effect on the external magnetic field and be able to migrate to the surface layer in the photopolymerization system. Under light irradiation, more free radicals that can initiate polymerization are generated, playing an anti-oxidative inhibition role. In addition, the nano-metal particles on the surface of the noble metal atoms are active in the zero-valent state for the polymerization reaction. Therefore, the presence of Ag nanoparticles makes Fe3O4@MoS2@PEI@Ag magnetic nanoparticles show more positive activity. The combined action of multiple factors improves the polymerization efficiency of the photocuring resin system.

[0043] (2) It improves the dispersibility of magnetic nanoparticles and their binding ability with resins. The coiled molecular chain segments of PEI will form countless small polymer "cages", which serve as capping agents for silver nanoparticles to avoid the aggregation of silver nanoparticles, improve the dispersibility of magnetic nanoparticles, and also serve as binders between magnetic nanoparticles and resins to enhance their binding ability with resins.

[0044] (3) It enhances the anti-corrosion and antibacterial properties of the resin coating. MoS2 has a layered structure similar to graphene, with excellent lubricity and anti-wear and anti-compression properties. When it is filled in the pores of the coating resin as a component of the co-initiator, it can not only reduce the entry of corrosive media into the coating, but also have a certain inhibitory effect on the original corrosion rate, enhancing the anti-corrosion performance of the resin coating. Ag nanoparticles and Fe3O4 can inhibit bacterial growth and reduce bacterial reproduction, with good antibacterial properties. In the photocuring system, through the bridging effect of PEI, they can be further dispersed into the polymer to enhance the antibacterial property of the resin coating.

[0045] The present invention discloses Fe3O4@MoS2@PEI@Ag magnetic nanoparticles as a photocuring co-initiator, and its composition and structure are as follows: A layer of MoS2 is coated on the surface of Fe3O4 nanoparticles, and then PEI is grafted through chemical bonding to form a carrier on the surface of Fe3O4@MoS2 magnetic nanoparticles. Using PEI as a coupling agent, active free radicals are formed with Fe3O4@MoS2 magnetic nanoparticles during the photoreduction process. By reducing the noble metal salt AgNO3, all Ag nanoparticles are reduced to the surface of the particle carrier to prepare Fe3O4@MoS2@PEI@Ag magnetic nanoparticles, which can be used as a photocuring co-initiator. The Fe3O4@MoS2@PEI@Ag magnetic nanoparticles provided by the present invention have small size effect and superparamagnetism, can increase the concentration of surface initiators during the photocuring process, improve the photopolymerization efficiency, at the same time can reduce the aggregation of silver nanoparticles, avoid the waste of silver nanoparticles, have better catalytic performance, and also solve the problem that small-sized nanoparticles are not easy to recycle and reuse. The magnetic nanoparticles provided by the present invention can also optimize the antibacterial and corrosion resistance of polymer resins. Detailed implementation mode

[0046] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the embodiments provided in the following examples only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following examples and the features in the examples can be combined with each other.

[0047] A magnetic nanoparticle used as a photoinitiation co-initiator, in which a layer of molybdenum disulfide (MoS2) is coated on the surface of iron oxide nanoparticles (Fe3O4 NPs), and then polyetherimide (PEI) is grafted by chemical bonding to form a magnetic nanoparticle carrier. The carrier is used to form active free radicals during the photoreduction process to reduce the noble metal salt AgNO3, thereby preparing the Fe3O4@MoS2@PEI@Ag NPs magnetic nanoparticle photoinitiation co-initiator.

[0048] A preparation method of a magnetic nanoparticle used as a photoinitiation co-initiator is as follows:

[0049] (1) Preparation of Fe3O4 nanoparticles: Using NH3·H2O, FeCl2·4H2O, and FeCl3·6H2O as reaction materials, FeCl3·6H2O and FeCl2·4H2O are added to a reaction flask and mixed with distilled water to form a solution. The temperature is raised to 92 °C for reaction. After complete dissolution, ammonia water is slowly added dropwise (10 drops per minute) to adjust the pH to 9.0, and the reaction continues for 1 hour. Then, it is left to stand and cooled to room temperature. The synthesized product is first washed with distilled water, centrifuged at 8000 revolutions per minute for 5 minutes, then washed with ethanol, and centrifuged again at 8000 revolutions per minute for 5 minutes. After drying at 80 °C, the product Fe3O4 nanoparticles are obtained.

[0050] (2) Preparation of Fe3O4@MoS2: MoS2 microspheres and Fe3O4 NPs are added to distilled water. After ultrasonic dispersion (ultrasonic frequency is 30 Hz, power is 120 W, temperature is 30 °C, and ultrasonic dispersion for 20 minutes), the solution is transferred to a sealed reaction vessel and heated to 180 °C for reaction for 12 hours; then it is left to stand for 8 hours for natural cooling. The precipitated Fe3O4 is collected by a strong magnet H40, washed twice with distilled water and ethanol respectively, and dried at 50 °C for storage for later use.

[0051] (3) Preparation of Fe3O4@MoS2@PEI: Dissolve the synthesized Fe3O4@MoS2 in step (2) in toluene solution, and perform strong stirring at a speed of 1000 r / min for 40 minutes. Dropwise add γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) into the solution, and stir at room temperature (stir at a speed of 300 r / min for 25 minutes). Filter out the sediment through a filter, and then wash it with ethanol and water to obtain KH560-modified Fe3O4@MoS2 nanoparticles; Add the KH560-modified magnetic Fe3O4@MoS2 nanoparticles into the aqueous solution of polyethyleneimine (PEI), and let the KH560-modified magnetic Fe3O4@MoS2 nanoparticles completely enter the aqueous solution of polyethyleneimine (PEI), and mechanically stir at room temperature for 18 h at a speed of 200 r / min. After the reaction, collect the product with a strong magnet, and wash it 1 - 3 times with water and ethanol respectively to obtain Fe3O4@MoS2@PEI nanoparticles; The mass ratio of toluene solution to Fe3O4@MoS2 is 52:1, and the volume ratio of toluene solution to KH560 solution is 15:1; The concentration of the used PEI solution is 10 mg / mL.

[0052] (4) Preparation of silver-nanoparticle-coated Fe3O4@MoS2@PEI magnetic nanoparticles: Dissolve AgNO3 in ethanol solution by ultrasonic treatment. Mix the ethanol solution containing Fe3O4@MoS2@PEI magnetic microspheres and the ethanol solution of AgNO3 according to a volume ratio of 1:2 to obtain a mixed solution A. After the mixed solution A is heated and stirred (300 r / min) in a water bath for 1 h, a mixed solution B is obtained; Dropwise add the ethanol solution of n-butylamine into the mixed solution B to obtain a mixed solution C. Keep the water bath temperature unchanged, and continue to mechanically stir the mixed solution C (300 r / min) for about 3 h; The product is separated by a magnet, washed 1 - 3 times with absolute ethanol, and then vacuum-dried to obtain the final product Fe3O4@MoS2@PEI@Ag magnetic nanoparticles; The mass ratio of AgNO3 to ethanol solution is 1:33, the mass ratio of Fe3O4@MoS2@PEI to ethanol solvent is 1:60, the water bath temperature after mixing is 50 °C, the concentration of the ethanol solution of n-butylamine is 0.015 g / mL, the volume ratio to the mixed solution B is 1:20, the vacuum drying temperature is 60 °C, and the drying time is 3 h.

[0053] Preferably, the magnetic nanoparticles can be used in the field of ultraviolet curing. As a photoinitiator assistant, the dosage is 2.22% of the total amount of the photocurable resin, and it acts synergistically with the main initiator and other additives to improve the curing efficiency and product performance;

[0054] A typical UV system formulation is as follows:

[0055] Mixing: Add 45 g of polyurethane acrylate oligomer (Sartomer CN9010), 40 g of acrylate monomer (trimethylolpropane triacrylate), 1 g of magnetic nanoparticles (Fe3O4@MoS2@PEI@Ag magnetic nanoparticles), and 5 g of additives [1 g of leveling agent (BYK-333), 1 g of defoaming agent (BYK-066N), 3 g of adhesion promoter (Silquest A-174)] into a stirring container, and stir at a speed of 300 r / min for 30 minutes to fully mix and homogenize all components.

[0056] Adding photoinitiator: Under stirring, add 3 g of photoinitiator (1-hydroxycyclohexyl phenyl ketone) at a rate of 0.5 g per minute, and continue stirring for 20 minutes to ensure that the photoinitiator is completely dissolved and evenly dispersed.

[0057] Coating: Use a suitable coating method (such as scraping, spraying, etc.) to evenly coat the prepared UV resin system on a stainless steel substrate.

[0058] Curing: Place the coated stainless steel substrate under a 500W 365nm ultraviolet lamp and irradiate for 150 s to cure the coating.

[0059] Post-treatment: After curing, place the product at room temperature for 24 hours to further stabilize its performance.

[0060] Example 1

[0061] A preparation method of magnetic nanoparticles as a photo-curing co-initiator. In step (1), FeCl3·6H2O: 11 parts by weight; FeCl2·4H2O: 8 parts by weight; distilled water: 4 parts by weight;

[0062] That is, the mass ratio of FeCl3·6H2O and FeCl2·4H2O to the solvent distilled water is 11:8:4.

[0063] In step (2), the mass ratio of MoS2 microspheres and Fe3O4 NPs to distilled water is 2:1:60.

[0064] The remaining content is the same as that of the above-mentioned magnetic nanoparticles as a photo-curing co-initiator and its preparation method.

[0065] Comparative Example 1

[0066] The difference between this comparative example and Example 1 is only that: in step (1), the added masses of FeCl3·6H2O and FeCl2·4H2O and the solvent distilled water are both 2 times the added amounts in Example 1. The concentration of the PEI solution is 20 mg / mL.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is only that: in step (2), the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 4:1:120.

[0069] Comparative Example 3

[0070] The difference between this comparative example and Example 1 is only that: in step (4), the mass ratio of AgNO3 to ethanol solution is 3:33. That is, the mass ratio of AgNO3 to ethanol solution of 1:33 is replaced by the mass ratio of AgNO3 to ethanol solution of 3:33.

[0071] Comparative Example 4: Remove FeCl2·4H2O

[0072] The difference between this comparative example and Example 1 is only that: in step (1), FeCl2·4H2O is not added.

[0073] Comparative Example 5: Remove the ethanol solution of n-butylamine

[0074] The difference between this comparative example and Example 1 is only that: in step (4), the ethanol solution of n-butylamine is not added dropwise to the mixture B to obtain the mixture C, and the water bath temperature is kept unchanged. After obtaining the mixture B in this comparative example, the mixture B is continuously mechanically stirred for about 3 h.

[0075] Comparative Example 6: Remove the toluene solution

[0076] The difference between this comparative example and Example 1 is only that: in step (1), FeCl3·6H2O: 22 parts by weight; FeCl2·4H2O: 16 parts by weight; distilled water: 8 parts by weight.

[0077] In step (3), γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) is added dropwise to Fe3O4@MoS2, ultrasonically dispersed with 200 W, and then washed with ethanol and water to obtain KH560-modified Fe3O4@MoS2 nanoparticles.

[0078] Comparative Example 7

[0079] The difference between this comparative example and Example 1 is only that:

[0080] In step (1), FeCl3·6H2O: 22 parts by weight; FeCl2·4H2O: 16 parts by weight; distilled water: 6 parts by weight;

[0081] In step (2), the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 2:1:70;

[0082] In step (3), the volume ratio of the toluene solution to the KH560 solution is 20:1; the concentration of the PEI solution used is 30 mg / mL.

[0083] Comparative Example 8

[0084] The difference between this comparative example and Example 1 is only that:

[0085] In step (2), the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 4:1:30.

[0086] Comparative Example 9

[0087] The difference between this comparative example and Example 1 is only that:

[0088] In step (1), FeCl3·6H2O: 11 parts by weight; FeCl2·4H2O: 10 parts by weight; distilled water: 6 parts by weight;

[0089] In step (2), the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 6:1:30.

[0090] Comparative Example 10

[0091] The difference between this comparative example and Example 1 is only that:

[0092] In step (4), the mass ratio of AgNO3 to the ethanol solution is 3:33; the concentration of the n-butylamine ethanol solution is 0.01 g / mL.

[0093] Comparative Example 11

[0094] The difference between this comparative example and Example 1 is only that:

[0095] In step (2), the mass ratio of MoS2 microspheres, Fe3O4 NPs to distilled water is 4:3:60;

[0096] In step (3), the volume ratio of the toluene solution to the KH560 solution is 13:1;

[0097] In step (4), the mass ratio of AgNO3 to the ethanol solution is 3:33; the concentration of the n-butylamine ethanol solution is 0.01 g / mL.

[0098] Comparative Example 12

[0099] The difference between this comparative example and Example 1 is only that:

[0100] This comparative example only prepared Fe3O4@MoS2@PEI nanoparticles without the Ag nanoparticle modification in step (4). The resulting product is Fe3O4@MoS2@PEI, rather than the complete Fe3O4@MoS2@PEI@Ag. This difference directly affects the functionality (e.g., catalytic and antibacterial properties) and stability of the material, further validating the necessity of step (4) in the present invention.

[0101] Comparative Example 13

[0102] The difference between this comparative example and Example 1 is only that:

[0103] In step (3), KH560 is added all at once.

[0104] Comparative Example 14

[0105] The difference between this comparative example and Example 1 is only that:

[0106] In step (2), MoS2 microspheres and Fe3O4 NPs are added to distilled water, and then directly transferred to a sealed reaction vessel for heating reaction without ultrasonic dispersion; after the reaction is completed, the precipitated Fe3O4 is collected using a strong magnet H40;

[0107] X-ray diffraction tests revealed that the prepared Fe3O4@MoS2 contained a high level of impurities and was of poor quality. The lack of ultrasonic dispersion and the use of a static cooling process in this comparative example resulted in significantly increased impurity content (e.g., 5-10% Fe2O3 and 3-8% unreacted raw material). However, Example 1 reduced the impurity content to negligible levels (e.g., <2% Fe2O3) by optimizing the dispersion conditions.

[0108] Comparative Example 15

[0109] The difference between this comparative example and Example 1 is only that:

[0110] In step (2), the mass ratio of MoS2 microspheres and Fe3O4NPs to distilled water is 4:1:30, and the reaction temperature is 200℃.

[0111] After photocatalytic performance testing, it was found that the quality of the finally obtained Fe3O4@MoS2 was poor when used, and the catalytic performance was reduced by 14%.

[0112] The Fe3O4@MoS2@PEI@Ag magnetic nanoparticles provided by the present invention have a small size effect and superparamagnetism. The small size effect is characterized by electrical testing using a four-terminal resistance tester, and the superparamagnetism is characterized by magnetic testing using a magnetic measuring instrument. The test results are shown in Table 1.

[0113] In superparamagnetism, the total magnetocrystalline anisotropy energy is proportional to K1V, and the thermal perturbation energy is proportional to kT (where K1 is the magnetocrystalline anisotropy constant, V is the particle volume, k is the Boltzmann constant, and T is the absolute temperature of the sample). When the particle volume decreases to a certain value, the thermal perturbation energy will be comparable to the total magnetocrystalline anisotropy energy, and the direction of the magnetic moment within the particle may change repeatedly between an easy magnetization direction and another easy magnetization direction as a whole over time.

[0114] Table 1 Electromagnetic test results of nanoparticles

[0115]

[0116]

[0117] In Table 1, it is reduced to: comparison with the performance parameters of the untreated raw materials or standard samples (such as unmodified Fe3O4, pure MoS2).

[0118] The unmodified Fe3O4 is the Fe3O4 nanoparticles obtained in step (1) of Example 1.

[0119] The pure MoS2 is the purchased MoS2 microspheres.

[0120] The magnetic properties are compared with those of unmodified Fe3O4; the electrical properties are compared with those of pure MoS2.

[0121] The catalytic performance test quantifies the material activity through the photocatalytic degradation rate and electrochemical parameters (such as overpotential). Photocatalytic degradation experiment (following ISO 10678:2010 standard); electrochemical test (following ASTM G61 standard).

[0122] A timer is used to determine the surface drying time of the polymer resin. The curing standard is the finger-touch method, that is, gently touching the surface of the coating film does not adhere to the fingers. Observe and record once every 1 minute, and record the surface drying time based on the resin surface not sticking to the hand. The antibacterial performance test of the polymer resin is carried out according to GB / T 21866-2008 "Determination Method and Antibacterial Effect of Antibacterial Coatings (Paint Films)". The antibacterial durability can be evaluated by measuring the minimum inhibitory concentration (MIC) to determine the antibacterial activity of magnetic nanoparticles against microorganisms or by evaluating the damage to the bacterial cell membrane and the living and dead state of bacteria by cell membrane damage dyes (such as ethidium bromide). The neutral salt spray corrosion resistance test of the polymer resin is carried out according to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test". The test results are shown in Table 2.

[0123] Table 2 Performance test results of each example and comparative example

[0124]

[0125]

[0126] In Table 2, for the neutral salt spray test, excellent means no corrosion and rust spot area = 0%; good means slight corrosion and rust spot area < 5%; fair means moderate corrosion and rust spot area of 5 - 10%; poor means severe corrosion and rust spot area > 10%.

[0127] Example 1 is a kind of Fe3O4@MoS2@PEI@Ag magnetic nanoparticles provided by the present invention as a photo - curing co - initiator. In Comparative Example 1 - Comparative Example 3, the amounts of FeCl2·4H2O, FeCl3·6H2O, and PEI (Comparative Example 1) were changed; the amount of MoS2 microspheres (Comparative Example 2); the amount of AgNO3 solution (Comparative Example 3). In Comparative Example 4, FeCl2·4H2O was removed. In Comparative Example 5, the ethanol solution of n - butylamine was removed. In Comparative Example 6, the toluene solution was removed. In Comparative Example 7, the amounts of FeCl2·4H2O, the ratio of the amounts of FeCl3·6H2O and FeCl2·4H2O, the amount of distilled water as the solvent of MoS2, the volume ratio of toluene solution and KH560 solution, and the concentration of PEI solution and the concentration of the ethanol solution of n - butylamine were changed respectively.

[0128] It can be seen from the performance test results that compared with Example 1, the comparative examples have differences in many performance indicators: compared with Comparative Example 4, the antibacterial rate of Example 1 is significantly improved, indicating that whether to add FeCl2·4H2O will affect the bacterial survival rate.

[0129] Compared with Comparative Example 8 and Comparative Example 9, the corrosion resistance of Example 1 is significantly improved, indicating that the dissolution amount of MoS2 particles will affect the corrosion resistance;

[0130] Compared with Comparative Example 10 and Comparative Example 11, the curing rate of Example 1 is significantly reduced, indicating that the amount of Ag particles will significantly affect the curing rate, and the decrease in the concentration of the ethanol solution of n - butylamine will lead to incomplete attachment of silver nanoparticles and reduce the curing rate.

[0131] The Fe3O4@MoS2@PEI@Ag magnetic nanoparticles provided by the present invention have small - size effect and superparamagnetism, can increase the concentration of surface initiator in the photo - curing process, improve the photo - polymerization efficiency, at the same time can reduce the aggregation of silver nanoparticles, avoid the waste of silver nanoparticles, solve the problem that small - size nanoparticle catalysts are not easy to recycle and reuse, and have better catalytic performance. The magnetic nanoparticles provided by the present invention can also optimize the antibacterial property and corrosion resistance of polymer resins.

[0132] Example 2

[0133] The difference between this embodiment and Embodiment 1 is only as follows: In step (1), the dropping rate of ammonia water is 15 drops per minute; the temperature is raised to 90 °C for reaction. The synthesized product is first washed with distilled water, centrifuged at 4000 r / min for 6 min, then washed with ethanol, and centrifuged again at 4000 r / min for 6 min. After heating and drying at 90 °C, the product Fe3O4 nanoparticles are obtained;

[0134] In step (2), it is heated to 190 °C for reaction for 24 hours, then left to stand for 6 h for natural cooling, and finally dried at 60 °C for storage for later use;

[0135] In step (3), it is mechanically stirred at 200 r / min at room temperature for 20 h;

[0136] In step (4), the mixture A is heated by water bath and stirred at 150 r / min for 0.5 h; the mixture C continues to be mechanically stirred at 150 r / min for 3 h; the vacuum drying time is 4 h.

[0137] In the method of using the UV resin system, 3 g of photoinitiator is added at a rate of 0.3 g per minute. After curing is completed, the product is placed at room temperature for 48 hours.

[0138] Embodiment 3

[0139] The difference between this embodiment and Embodiment 1 is only as follows: In step (1), the temperature is raised to 95 °C for reaction;

[0140] In step (2), it is left to stand for 10 h for natural cooling.

[0141] In the method of using the UV resin system, 3 g of photoinitiator is added at a rate of 0.6 g per minute.

[0142] It should be understood that, in order to streamline the present disclosure and assist in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment or the description thereof. However, the disclosed method should not be construed as reflecting the intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims, the inventive aspects lie in less than all of the features of the foregoing disclosed embodiments. Accordingly, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim stands on its own as a separate embodiment of the present invention.

[0143] Although the present invention has been described in terms of a limited number of embodiments, those skilled in the art will appreciate, upon reading the foregoing, that other embodiments can be contemplated within the scope of the invention as thus described. Further, it should be noted that the language used in this specification has been principally selected for readability and instructional purposes and not to limit or define the subject matter of the invention. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. For the scope of the present invention, the disclosure herein is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0144] The foregoing are only the preferred embodiments of the present invention, and it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A magnetic nanoparticle as a photoinitiating co - initiator, characterized in that, It is Fe3O4@MoS2@PEI@AgNPs magnetic nanoparticles.

2. The preparation method of a magnetic nanoparticle as a photoinitiator co-initiator according to claim 1, wherein, It includes the following steps: (1) Preparation of Fe3O4 nanoparticles: Using NH3·H2O, FeCl2·4H2O, and FeCl3·6H2O as reaction materials, the mass ratio of FeCl3·6H2O, FeCl2·4H2O to the solvent distilled water is 11:8:4; Add FeCl3·6H2O and FeCl2·4H2O into the reaction flask and mix them with distilled water to prepare a solution, raise the temperature to 90 - 95 °C for reaction, after complete dissolution, slowly add ammonia water to adjust the pH to 9.0, continue the reaction for 1 hour, let it stand and cool to room temperature, the synthesized product is first washed with distilled water, centrifuged at 4000 - 8000 revolutions per minute for 5 - 6 minutes, then washed with ethanol, and centrifuged again at 4000 - 8000 revolutions per minute for 5 - 6 minutes, and dried by heating at 80 - 90 °C to obtain the product Fe3O4 nanoparticles; (2) Preparation of Fe3O4@MoS2: Add MoS2 microspheres and Fe3O4 nanoparticles into distilled water, the mass ratio of MoS2 microspheres, Fe3O4 nanoparticles to distilled water is 2:1:60; After ultrasonic dispersion, transfer the solution to a sealed reaction vessel, heat to 180 - 190 °C for reaction for 12 - 24 hours; Then let it stand for 6 - 10 hours for natural cooling, collect the precipitated Fe3O4 with a strong magnet, wash it with distilled water and ethanol, and dry it at 50 - 60 °C for storage for later use; (3) Preparation of Fe3O4@MoS2@PEI: Dissolve the Fe3O4@MoS2 synthesized in step (2) in toluene solution, the mass ratio of toluene solution to Fe3O4@MoS2 is 52:1, stir at a speed of 1000 r / min for 40 minutes, dropwise add γ-(2,3-epoxypropoxy)propyltrimethoxysilane KH560 into the solution, the volume ratio of toluene solution to KH560 solution is 15:1; Stir at a speed of 300 r / min at room temperature for 25 minutes, filter out the sediment through a filter, and then wash it with ethanol and water to obtain KH560-modified Fe3O4@MoS2 nanoparticles; Add the KH560-modified magnetic Fe3O4@MoS2 nanoparticles into a 10 mg / mL aqueous solution of polyethyleneimine PEI, and mechanically stir at 200 r / min at room temperature for 18 - 20 hours. After the reaction, collect the product with a strong magnet, and wash it with water and ethanol respectively to obtain Fe3O4@MoS2@PEI nanoparticles; (4) Preparation of Fe3O4@MoS2@PEI magnetic nanoparticles coated with silver nanoparticles: AgNO3 was added to a 95% ethanol solution and dissolved by ultrasonic treatment. The 95% ethanol solution containing Fe3O4@MoS2@PEI nanoparticles was mixed with the 95% ethanol solution containing AgNO3 at a volume ratio of 1:2 to obtain a mixed solution A. After the mixed solution A was heated in a water bath and stirred at 150 - 300 r / min for 0.5 - 1 h, a mixed solution B was obtained. The 95% ethanol solution of n-butylamine was added dropwise to the mixed solution B to obtain a mixed solution C. Keeping the water bath temperature unchanged, the mixed solution C was continuously stirred mechanically at 150 - 300 r / min for 3 h; The product was separated by a strong magnet, washed with absolute ethanol, and dried in vacuo to obtain the final product Fe3O4@MoS2@PEI@Ag magnetic nanoparticles; The mass ratio of AgNO3 to the 95% ethanol solution was 1:33; The mass ratio of Fe3O4@MoS2@PEI nanoparticles to the 95% ethanol solvent was 1:60; The concentration of the 95% ethanol solution of n-butylamine was 0.015 g / mL, and the volume ratio to the mixed solution B was 1:

20.

3. The preparation method according to claim 2, characterized in that, In step (1), the dropping speed was slow, at 10 - 15 drops per minute.

4. The preparation method according to claim 2, characterized in that, In step (2), the ultrasonic frequency was 30 Hz, the power was 120 W, the temperature was 30 °C, and ultrasonic dispersion was carried out for 20 min; the strong magnet was strong magnet H40, the magnetic attraction intensity was 2000 - 3000 gauss, and the magnetic field intensity was 3000 - 5000 gauss.

5. The preparation method according to claim 2, characterized in that, In step (4), the water bath temperature was 50 °C; the vacuum drying temperature was 60 °C, and the drying time was 3 - 4 h.

6. Application of the magnetic nanoparticles as a photo-curing co-initiator according to claim 1 in the field of photo-curing with light of 300 - 800 nm.

7. A UV resin system comprising the magnetic nanoparticles as a photo-curing co-initiator described in claim 1, characterized in that, It includes the following components: 45 parts by weight of polyurethane acrylate oligomer, 40 parts by weight of acrylate monomer, 1 part by weight of magnetic nanoparticles as a photo-curing co-initiator, 5 parts by weight of additives, and 3 parts by weight of photo-initiator; The additives include 1 part by weight of leveling agent, 1 part by weight of defoaming agent, and 3 parts by weight of adhesion promoter.

8. The UV resin system according to claim 7, characterized in that, The polyurethane acrylate oligomer is Sartomer CN9010; The acrylate monomer is trimethylolpropane triacrylate; The leveling agent is BYK-333; The defoaming agent is BYK-066N; The adhesion promoter is Silquest A-174; The photo-initiator is 1-hydroxycyclohexyl phenyl ketone.

9. The method of using the UV resin system according to claim 7, characterized in that, It includes the following steps: Mixing: Add other components except the photo-initiator to a stirring container and stir at a speed of 300 r / min for 30 minutes to make each component fully mixed and uniform; Adding photo-initiator: Under the stirring state, add 3 g of photo-initiator at a speed of 0.3 - 0.6 g per minute, and continue to stir at a speed of 300 r / min for 20 minutes to ensure that the photo-initiator is completely dissolved and dispersed evenly; Coating: Use a doctor blade or spraying to evenly coat the prepared UV resin system on a stainless steel substrate, with a thickness < 100 μm; Curing: Place the coated stainless steel substrate under a 365 nm ultraviolet lamp with a power of 500 W and irradiate for 150 s to cure the coating; Post-treatment: After curing, place the product at room temperature for 24 to 48 hours.

10. The application of the UV resin system according to claim 7 in a corrosion-resistant and antibacterial coating.

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