CN111732738B

CN111732738B - Method for preparing micro-nano magnetic composite particles and micro-nano magnetic composite particles

Info

Publication number: CN111732738B
Application number: CN202010566047.XA
Authority: CN
Inventors: 陶光明; 马庶祺; 向远卓; 曾少宁; 王蕊; 李思苒
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2021-09-03
Anticipated expiration: 2040-06-19
Also published as: CN113754901A; CN111732738A

Abstract

Discloses a method for preparing micro-nano magnetic composite particles and the composite particles. The preparation method of the micro-nano magnetic composite particles comprises the step of carrying out fluidization treatment on micro-nano magnetic fibers containing micro-nano magnetic particles and a base material. The magnetic micro-nano composite particles disclosed by the application are uniform and controllable in size, the error range of the size of the main particles can be adjusted to be 1% -10%, the magnetic micro-nano composite particles can be improved according to process optimization, the base materials are mainly polymers, inorganic glass materials and composite materials thereof, the polymer materials, the glass materials and the composite materials thereof can be simultaneously used in the same micro-nano magnetic composite particles, the particle structure is controllable in height, can be of a spherical structure, a double-spherical structure, a wrapped structure, a fusiform structure, a flat structure, a rod-shaped structure, a ring-shaped structure or a combined structure based on the spherical structure, the double-spherical structure, the wrapped structure, the fusiform structure, the flat structure, the rod-shaped structure, the ring-shaped structure and the fried egg shape, the process is simple, the large-scale production can be realized, and the production efficiency is high.

Description

Method for preparing micro-nano magnetic composite particles and micro-nano magnetic composite particles

Technical Field

The invention relates to the technical field of micro-nano particle preparation, in particular to a method for preparing micro-nano magnetic composite particles and micro-nano magnetic composite particles.

Background

In biological micro-nano medical materials, micro-nano magnetic particles mainly based on polymers are receiving more and more attention due to good biocompatibility and wide potential application, and the micro-nano magnetic particles are widely applied to the aspects of enrichment and separation of bioactive substances, drug carriers, diagnosis and treatment of diseases and the like. The magnetic micro-nano particles mainly show two characteristics of magnetism and micro-nano scale. The magnetic properties help to achieve magnetic targeting of the particles, with different particle sizes having different applications in biomedicine.

In the application in the organism, the particles with the micro-nano scale can be more easily permeated into the tissue, and the magnetic particles can be accurately conveyed to the specific area of the tissue by the directional control of the external magnetic field, so the magnetic particles are widely applied to directional drug delivery, contrast enhancers, tumor thermotherapy and the like. The magnetic particles used for directional drug delivery and contrast enhancement have wide scale range, no particles with single size can reach different tissue areas, the drug or the imaging contrast agent is encapsulated inside the micro-nano particles, and the micro-nano particles are delivered to a required area through an external magnetic field, so that the directional drug delivery or the contrast enhancement is realized. Magnetic particles used for tumor hyperthermia are generally of nanometer scale, since nanometer-scale particles are more likely to penetrate into tumor tissue and stay for a long time due to a high penetration long-retention effect. In 2000, Magforce company in germany applied ultra-small magnetic nanoparticles to tumor hyperthermia, which injected 15 nm magnetic nanoparticles into glioblastoma in brain, and the magnetic nanoparticles generated heat under the action of alternating magnetic field to induce tumor cell apoptosis.

In the application in vitro, the micro-nano magnetic particles have the advantages of magnetic control and affinity separation, and are widely applied to the aspects of immunodetection, nucleic acid extraction, cell screening and the like. The magnetic particles used for immunoassay are usually in the size range of several micrometers, and antibodies are immobilized on the surface of the magnetic particles by means of covalent coupling, so as to provide an immunoreactive interface. The magnetic particle used for nucleic acid extraction is usually in the range of hundreds of nanometers to tens of micrometers in size, hydroxyl is modified on the surface of the particle, nucleic acid is extracted by utilizing the adsorption effect of the hydroxyl on the nucleic acid under the high-salt environment, and the nucleic acid is eluted in low-salt eluent, so that the separation and extraction of the nucleic acid are realized. The magnetic particle size for cell screening is usually in the range of tens of nanometers to tens of micrometers, and glucan is modified on the surface of the particle, so that specific cells are labeled and screened.

In the application of biomedicine, the magnetic particles are mainly polymers, and have good biocompatibility and surface modification universality, so that the magnetic particles have wide application in vivo and in vitro, and the large-scale preparation method has the advantages of high size assimilation of the magnetic micro-nano particles, high controllability of size regulation intervals across micro-nano and internal and external structures and magnetic doped particle distribution, and simple preparation process, and can ensure that the magnetic particles have bright prospect in the application of biomedicine.

So far, common preparation methods of micro-nano magnetic particles mainly made of polymer materials include an embedding method, a microfluidic method, a deposition method and the like. The embedding method is a method of polymerizing a monomer or a prepolymer on the surface of a magnetic doped particle to embed the magnetic doped particle in a polymer formed by polymerizing the monomer or the prepolymer to form a magnetic polymer particle. However, the method is difficult to regulate the structure of the magnetic polymer particles, the size distribution of the prepared magnetic polymer particles is wide, and the particle diameter is difficult to control. The microfluidics method is that monomer or prepolymer, initiator, dispersant are mixed in solution containing magnetic doping particles to form emulsion, and the emulsion passes through a capillary with a diameter ranging from tens of micrometers to hundreds of micrometers, and then the emulsion is polymerized to form polymer particles under the irradiation of heat bath or ultraviolet. However, in the above method, the size of the magnetic polymer particles is limited to a range of several tens micrometers to one hundred micrometers, the specific surface area is small, and the magnetic content is low. The deposition method is to use other methods to prepare particles without magnetic doping particles, and to deposit the magnetic doping particles on the surface of the polymer through additional physical and chemical deposition equipment. In the method, physical and chemical deposition equipment with higher requirements on dimensional accuracy is expensive, and the polymer particles prepared by the method are unstable in combination of the magnetic doped particles and the polymer surface, so that the simple and large-scale preparation of the polymer particles is difficult to realize.

Chinese patent CN101440166A discloses a magnetic polymer particle, which is composed of an outer layer of polymer and one or more magnetic cores embedded in the polymer, the weight ratio of the outer layer of polymer to the magnetic cores is 0.4-10:1, the magnetic cores are composed of gel type polymer and one or more magnetic particles embedded in the gel type polymer, and the weight ratio of the gel type polymer to the magnetic particles is 1.2-100: 1. It further discloses that the preparation method of the composite magnetic cation exchange resin comprises the following steps: (1) mixing a monomer, an initiator and a cross-linking agent, carrying out prepolymerization at 60-80 ℃, adding magnetic particles, a surface auxiliary agent and a dispersing agent which account for 1-83% of the weight of a prepolymerization solution, completing a polymerization reaction at 60-95 ℃, washing and drying to obtain the required magnetic core; (2) mixing a monomer, an initiator, a cross-linking agent, a pore-forming agent and a dispersing agent, pre-polymerizing at 60-80 ℃, adding magnetic cores accounting for 10-250 wt.% of the total weight of the monomer and the cross-linking agent, completing polymerization reaction at 60-95 ℃, and obtaining magnetic polymer particles after washing, drying, sulfonation or hydrolysis. However, the magnetic polymer particles disclosed therein, in which the weight ratio of the magnetic doping particles (one or several of iron, iron alloy and iron oxide) to the whole microsphere is only 0.09-27 wt.%, have limited magnetic properties and still need to be further improved; the size of the composite magnetic cation exchange resin is 50-1200 mu m, and magnetic polymer particles with smaller size cannot be obtained; in the polymer particles, the magnetic doped particles are uniformly contained in the composite resin in space, and the spatial distribution structure of the magnetic doped particles cannot be regulated, so that the magnetic doped particle distribution structure of the particles cannot be regulated.

Chinese patent CN101838426A discloses a method for preparing magnetic polymer particles, which adoptsNano Fe prepared by chemical coprecipitation method₃O₄The surfaces of the particles are coated by hydrophobic layers and are dissolved in hydrophobic alkene monomers to prepare stable magnetofluid to form an oil phase. One or more alkene monomers are made into nonmagnetic seed particles and an aqueous phase is formed. After the oil phase and the water phase are fully vibrated, mixed and swelled, the polymerization is initiated to prepare the magnetic polymer microspheres, but the size of the magnetic polymer particles is only between 0.01 and 5 mu m, and the size regulation range of the particles still needs to be further improved; the magnetic polymer particles, the magnetic doped particles Fe₃O₄The weight ratio of the total microspheres is 0.5-55 wt.%, which still needs to be further improved; in the magnetic polymer particles, the magnetic doping particles are uniformly contained in the polymer in space, so that the spatial distribution structure of the magnetic doping particles cannot be regulated, and further the magnetic doping particle distribution structure of the particles cannot be regulated.

Chinese patent CN103819708A discloses a method for preparing magnetic polymer particles, which comprises directly fixing magnetic particles on the surface of a plastic core by physical melting, and then spraying a polymer solution on the core-magnetic powder layer particles to obtain core-magnetic powder layer-polymeric coating layer particles, and making into millimeter-sized magnetic beads, wherein the particle size of the magnetic polymer particles is 0.01-100 mm, and the size control range of the particles still needs to be further improved; in the magnetic polymer particles, the weight of the magnetic doped particles accounts for 1-25 wt%, the magnetic performance is limited, and further improvement is needed; in the magnetic polymer particles, the magnetic doping particles are only distributed in the interlayer in space, the space distribution structure of the magnetic doping particles cannot be regulated, and further the distribution structure of the magnetic doping particles of the particles cannot be regulated.

Chinese patent CN1732386A discloses a method for preparing magnetic polymer particles, which comprises the steps of preparing porous epoxy particles by a chemical synthesis method, dissolving the porous epoxy particles, and adding FeCl₂×4H₂O and FeCl₃×6H₂O is suspended, cooled to 50 ℃ and stirred for a few minutes, NH is added₃Aqueous solution, and the temperature was raised to 80 ℃ for 2 hours. Cooling the suspensionPurifying the particles by using water through a plurality of circulative centrifugal separation, and obtaining magnetic polymer particles after purification, wherein the size of the magnetic polymer particles is 0.3-100 mu m, and the particle size regulation range is to be further improved; in the magnetic polymer particles, the magnetic doping particles are uniformly contained in the polymer in space, so that the space distribution structure of the magnetic doping particles cannot be regulated, and further the distribution of the magnetic doping particles of the particles cannot be regulated.

In addition, the chinese patent also discloses a series of magnetic particles comprising non-polymeric materials.

Chinese patent CN107614458A discloses a method for producing silane-encapsulated nano-magnetic particles, which have small size and high magnetic moment, but the prepared particles utilize a separation device of external and internal magnetic fields to achieve dispersion of the particles, and the preparation process is difficult to control precisely.

Chinese patent CN109402052A discloses a method for preparing magnetic nanoparticles for capturing exosomes in blood, which further discloses the method: in solution to obtain SiO precipitate₂Coated magnetic micro-nano particles. Mixing ferric chloride hexahydrate and ferrous chloride tetrahydrate, dissolving in distilled water to obtain a mixed solution, stirring, uniformly mixing, heating, and adding an alkali liquor to obtain granules. However, the obtained micro-nano particles are irregular in shape, the size and the shape of the synthesized particles cannot be controlled, and the particle preparation material is single and is influenced by the chemical properties of the particles.

The method aims at overcoming the defects in the prior art in size control, structure control and simple large-scale preparation of magnetic particles, and the inventor invents a preparation method of micro-nano magnetic particles and particle groups based on fluid instability in long-term research.

Disclosure of Invention

In view of the above defects of the prior art, the present invention provides a method for preparing micro-nano magnetic composite particles and particle groups based on fluid instability, the micro-nano magnetic composite particles prepared by the method (wherein the substrate material is an amorphous material which takes a high molecular polymer, inorganic glass and a composite material taking the polymer as the substrate material as the main component) have the advantages of high size assimilation, size regulation and control interval spanning micro-nano, adjustable internal and external structures and magnetic doped particle distribution height, high magnetic particle doping concentration, simple preparation process, large-scale preparation and the like, meanwhile, due to the coating effect of the macromolecular organic matter, the prepared magnetic polymer micro-nano composite particles also have the advantages of good biocompatibility, biodegradability and the like, the method has wider application in the technical fields of micro-nano biological medical treatment such as drug delivery in organisms, cell screening, biological imaging and the like.

The specific technical scheme of the invention is as follows:

1. a preparation method of micro-nano magnetic composite particles is characterized by comprising the following steps:

and carrying out fluidization treatment on the micro-nano magnetic fiber containing the micro-nano magnetic particles and the base material.

2. The production method according to item 1, characterized in that the fluidization treatment is selected from at least one of: heat treatment and chemical treatment.

3. The method according to claim 2, wherein the heating process is to heat the micro-nano magnetic fiber as a whole.

4. The preparation method according to item 2, wherein the heating treatment is local heating of the micro-nano magnetic fiber.

5. The production method according to claim 2, wherein the heat treatment temperature is 60 ℃ to 500 ℃ and the heat treatment time is 1s to 24 hours.

6. The production method according to claim 2, wherein the heat treatment temperature is 200 ℃ to 300 ℃ and the heat treatment time is 30min to 2 h.

7. The preparation method according to the item 2, wherein the micro-nano magnetic fiber is wound on a glass tube, both ends of the glass tube are fixed, and the glass tube is placed in a muffle furnace for heating treatment.

8. The preparation method according to item 1, further comprising after the fluidization treatment, directionally dissolving the fiber cladding of the fluidized micro-nano magnetic fibers by using a chemical solvent to obtain micro-nano magnetic composite particles.

9. The production method according to item 8, characterized in that the chemical solvent is selected from at least one of: acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene solvent, ethyl acetate, butyl acetate, hydrofluoric acid, alkali metal hydroxide solution.

10. The preparation method according to item 1, further comprising, after the fluidizing treatment, performing extrusion treatment on the fluidized micro-nano magnetic fiber while maintaining the glass transition temperature of the substrate, so that the substrate is permanently deformed by the extrusion treatment.

11. The preparation method according to item 10, further comprising after the extrusion treatment, directionally dissolving the fiber cladding of the extruded micro-nano magnetic fiber by using a chemical solvent to obtain the micro-nano magnetic composite particles.

12. The preparation method according to item 2, wherein the fluidization treatment is a fluidization treatment of the micro-nano magnetic fibers in a chemical solvent atmosphere.

13. The production method according to item 12, wherein the chemical solvent is selected from at least one of polar and nonpolar solvents.

14. The production method according to item 13, characterized in that the chemical solvent is selected from at least one of: acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene solvent, ethyl acetate, butyl acetate, hydrofluoric acid, alkali metal hydroxide solution.

15. The method according to any one of claims 1 to 14, wherein the micro-nano magnetic particles are selected from at least one of the following: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles;

preferably, the metal magnetic particles are selected from one or more of the following: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles;

preferably, the metal compound magnetic particles are metal oxide magnetic particles; more preferably, the metal compound magnetic particles are selected from one or two of: fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles;

preferably, the metal alloy magnetic particles are selected from one or more of the following: neodymium iron boron alloy magnetic particles, samarium cobalt alloy magnetic particles, nickel cobalt alloy magnetic particles, and iron cobalt alloy magnetic particles.

16. The production method according to any one of items 1 to 15, wherein the substrate is selected from at least one of: polymer, glass and composite material using the same as substrate material;

preferably, the polymer is a thermoplastic polymer;

preferably, the polymer is selected from one or two or more of: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether;

preferably, the glass is selected from one or two or more of the following: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

17. The production method according to any one of claims 1 to 16, wherein the number of particles produced at a time is 2 to 1000000000 per cm in size.

18. A micro-nano magnetic composite particle prepared by the preparation method of any one of items 1 to 17.

19. The micro-nano magnetic composite particles are characterized by comprising micro-nano magnetic particles and a base material;

preferably, the micro-nano magnetic particles are selected from at least one of the following: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles;

preferably, the substrate is selected from at least one of the following: polymer, glass and composite material using the same as base material.

20. The micro-nano magnetic composite particle according to item 19, wherein the polymer is a thermoplastic polymer; preferably, the thermoplastic polymer is selected from at least one of the following: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether.

21. The micro-nano magnetic composite particle according to item 19, wherein the glass is selected from at least one of: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, fluoride glasses, and any combination thereof.

22. The micro-nano magnetic composite particle according to item 19,

the metal magnetic particles are selected from one or more than two of the following: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles;

23. The micro-nano magnetic composite particle according to any one of claims 19 to 22, wherein the micro-nano magnetic particles are uniformly dispersed in the base material.

24. The micro-nano magnetic composite particle according to item 23, wherein the micro-nano magnetic particles are present in an amount of 0.01wt.% to 75wt.%, preferably 1wt.% to 75wt.%, based on the total weight of the micro-nano magnetic composite particle.

25. The micro-nano magnetic composite particle according to any one of claims 19 to 24, wherein the structure of the micro-nano magnetic composite particle is selected from at least one of the following structures: spherical structure, double spherical structure, wrapped structure, shuttle type structure, flat structure, omelette type structure, and any combination thereof.

26. The micro-nano magnetic composite particle according to item 25, wherein the micro-nano magnetic composite particle is a spherical structure, preferably a core-shell structure, wherein the mass percentage of the micro-nano magnetic particles in the core in the base material is different from the mass percentage of the micro-nano magnetic particles in the shell in the base material.

27. The micro-nano magnetic composite particle according to item 26, wherein the mass percentage of the micro-magnetic particles in the corresponding base material is gradually decreased along the core-shell direction in the micro-nano magnetic composite particle.

28. The micro-nano magnetic composite particle according to item 26, wherein the micro-nano magnetic composite particle comprises n shell structures, and n is an integer not less than 1.

29. The micro-nano magnetic composite particle according to item 28, wherein the micro-nano magnetic particles in at least two shell structures in the core-shell structure are different in mass percentage.

30. The micro-nano magnetic composite particle according to item 27, wherein the micro-nano magnetic particles gradually decrease in mass percentage from inside to outside in the shell structure.

31. The micro-nano magnetic composite particle according to item 25, wherein the micro-nano magnetic composite particle is a spherical structure, wherein a cross section obtained by cross-cutting the micro-nano magnetic composite particle along a diameter of the composite particle through a spherical center of the micro-nano magnetic composite particle, the cross section is divided into different parts by two radii and arcs of the cross section, and the mass percentage of the micro-nano magnetic particles in the different parts is different.

32. The micro-nano magnetic composite particle according to item 31, wherein the two radii of the cross section and the arcs thereof divide the cross section into two equal parts, and the mass percentage of the micro-nano magnetic particles in the two parts are different.

33. The micro-nano magnetic composite particle according to any one of claims 19 to 32, further comprising a metal wire, wherein the metal wire penetrates through the micro-nano magnetic composite particle.

34. The micro-nano magnetic composite particles according to claim 25, wherein the micro-nano magnetic composite particles are of a double-sphere structure, and the weight percentages of the micro-nano magnetic particles in the double-sphere structure are different or the same.

35. The micro-nano magnetic composite particle according to any one of claims 19 to 34, wherein the size error range of the magnetic composite particle is +/-0.1-10% of the size of the main particle

ADVANTAGEOUS EFFECTS OF INVENTION

(1) The size of the magnetic micro-nano composite particles is uniform and controllable, the error range of the size of the main particles can be adjusted to 1-10%, and the magnetic micro-nano composite particles can be improved according to process optimization;

(2) the magnetic micro-nano particle material base material mainly comprises a polymer, an inorganic glass material and a composite material taking the polymer as a base material, and the polymer material, the glass material and the composite material taking the glass material as the base material can be simultaneously contained in the same micro-nano magnetic composite particle;

(3) the particle structure is highly controllable, and can be spherical, double-spherical, wrapped, fusiform, flat, rod-shaped, ring-shaped, fried egg-shaped or a combined structure based on spherical, double-spherical, wrapped, fusiform, flat, rod-shaped, ring-shaped, fried egg-shaped.

(4) The preparation technology has the advantages of simple process, large-scale production and high production efficiency, and the weight of the particles prepared at one time can realize kilogram-level mass production in a laboratory level and ton-level mass production in the industry.

Drawings

Fig. 1-1 is a schematic view of a process for preparing micro-nano magnetic composite particles by using a heat treatment method according to the present invention.

Fig. 1-2 are schematic diagrams of a process for preparing micro-nano magnetic composite particles by using a solvent treatment method according to the present invention.

FIGS. 1-3 are schematic diagrams of the time course of the magnetic fibers of the present invention after being fluidized.

FIG. 2 is a schematic representation of the preparation of a single core micrometer magnetic composite particle of example 1.

FIG. 3 is a schematic diagram of high throughput parallel preparation of the nano-magnetic composite particles in example 2.

Fig. 4 is a schematic diagram of the preparation of the micrometer magnetic composite particles with the radial magnetic anisotropy structure in example 3.

Fig. 5 is a schematic diagram of the preparation of the micromagnetic composite particles having an azimuthal magnetic anisotropy structure in example 4.

FIG. 6 is a schematic diagram of the fabrication of the magnetic composite micro-particles with the magnetic structure of the contact assembly of example 5.

FIG. 7 is a schematic diagram of the preparation of the magnetic composite microparticle having the structure of "candied gourd string" in example 6.

FIG. 8 is a schematic diagram of the preparation of the magnetic composite microparticle having the structure of "Shuangshen" in example 7.

Fig. 9 is a schematic view of the preparation of the magnetic composite microparticle having the two-dimensional code structure in example 8.

Fig. 10 is a schematic diagram of the preparation of the micro magnetic composite particles having the triangular spindle structure in example 9.

FIG. 11 is a schematic view showing the preparation of the magnetic composite microparticle having a flat structure in example 12.

FIG. 12 is a schematic view showing the preparation of the omelet-type structured micro-magnetic composite particles of example 13.

FIG. 13 is a schematic view of a ring-type magnetic composite particle in example 14.

In fig. 1-1, 1 is a magnetic fiber, 2 is a heating device in a heat treatment process, 3 is a beaker containing a solvent for dissolving a cladding, 4 is a glass bottle filled with finally obtained magnetic micro-nano composite particles after being washed and dried by deionized water, and 5 is magnetic composite particles stored in the glass bottle.

In fig. 1-2, 6 is a glass bottle containing a chemical solvent or chemical solvent vapor, 7 is a glass bottle containing magnetic micro-nano composite particles finally obtained after being washed with deionized water and dried, and 8 is magnetic composite particles stored in the glass bottle.

In fig. 1-3, 9 is a magnetic fiber without fluidization, 10 is a fiber core, 11 is an intermediate state during fluidization, and 12 is a state in which the fiber forms a composite particle after fluidization.

13, 18, 23, 28, 33, 38, 43, 48, 53 in fig. 2,3,4, 5, 6, 7, 8, 9, 10 are magnetic fiber cross sections, 14, 19, 24, 29, 34, 39, 44, 49, 54 are magnetic fiber side perspective views, 15, 20, 25, 30, 35, 40, 45, 50, 55 are magnetic fiber cross sections in a fluidizing treatment method of magnetic fibers, 16, 21, 26, 31, 36, 41, 46, 51, 56 are irregular composite particles obtained in an intermediate state of the fluidizing treatment when the magnetic fibers are not treated, and 17, 22, 27, 32, 37, 42, 47, 52, 57 are spherical composite particles obtained in a final state of the fluidizing treatment.

In fig. 11, 58 and 62 are upper glass plates, and 59 and 63 are lower glass plates; 60. 64 is a preform drawn fiber; 61. and 65 are magnetic particles in the fiber, wherein 61 is a spherical magnetic particle, and 65 is a flat magnetic particle.

In fig. 12, 66 is a glass bottle containing chemical solvent or chemical solvent vapor, 67 is a platform for placing magnetic fiber in the glass bottle, 68 is magnetic fiber in the glass bottle on the platform, 69 is fried egg type granules formed after fluidization treatment, 70 is a side view of the fried egg type granules,

fig. 13, 71, shows the ring-shaped magnetic composite microparticle after selective removal of the core by chemical solvent.

Detailed Description

The present invention is described in detail in the following description of embodiments with reference to the figures, in which like numbers represent like features throughout the figures. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

It should be noted that certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, however, the description is given for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present invention is defined by the appended claims.

The magnetic particles are permanent magnetic or soft magnetic micro-nano particles.

The structural structure refers to that the cross section of the prepared micro-nano magnetic fiber can be prepared into any required structure, such as a single-concentration magnetic particle doped structure, a multi-concentration magnetic particle doped structure, a cladding-containing structure, a cladding-free structure, a high-melting-point functional material layer-containing structure and the like; and the cross-section of the fiber can be of any shape.

A "preform" is a preform of material that can be used to draw a fiber, the structure of which determines the structure of the fiber.

"hot drawing" means heating a partial region of a preform by a heat source to soften the preform and then manually or mechanically drawing the preform from one or both ends of the heated region, and is also called "hot drawing".

The 'co-drawing functional material' refers to a material which has material parameters, thermal expansion coefficient, softening temperature and the like matched with the magnetic composite material and can be hot-drawn together with the magnetic composite material into the micro-nano magnetic fiber.

The "coefficient of thermal expansion of the material" means that the material has expansion and contraction phenomena due to temperature change, and the coefficient of thermal expansion of the materials is matched, which means that different materials have the same or close to the same coefficient of thermal expansion. Matching of the thermal expansion coefficients of the materials ensures the consistency of the fiber structure with the preform structure.

The "glass transition temperature" refers to the lowest temperature at which molecular segments in an amorphous material can move, and the hot-drawing process microscopically shows the movement of the molecular chains of the material, so that the hot-drawing temperature is higher than the glass transition temperature. By glass transition temperature matched is meant that different materials have the same or close glass transition temperature, ensuring that the different materials can be hot drawn together into a fiber.

By "melt-matched" is meant that the functional material has a melting point near or above the glass transition temperature of the amorphous material used to ensure that the functional material is capable of forming a fiber with the amorphous material at the fiber hot-draw temperature.

By "mechanically synchronized" is meant that during the hot drawing process, the magnetically structured preform is drawn synchronously with the material of the high melting point functional layer at the same draw speed.

The "thermoplastic polymer" refers to a polymer which can be melted by repeated heating, molded in a softened or fluid state, and cooled to maintain the shape of a mold, and is a linear or high molecular compound containing a small amount of branched structures.

The PMMA is polymethyl methacrylate, has the advantages of high transparency, low price, easy machining and the like, and is a frequently used glass substitute material.

"SMMA" is a styrene methyl dimethacrylate copolymer, a polyacrylic copolymer.

"COC" is a cyclic olefin copolymer, a high value-added thermoplastic engineering plastic obtained by polymerizing cyclic olefins, and is widely used for manufacturing various optical, information, electric and medical materials because of its high transparency, low dielectric constant, excellent heat resistance, chemical resistance, melt flowability, barrier properties, dimensional stability, and the like.

The COP is a cycloolefin polymer, is used for medical optical parts and high-end medicine packaging materials, and has the following raw material characteristics: high transparency, low birefringence, low water absorption, high rigidity, high heat resistance, good vapor tightness and composite FDA standard.

"PC" is a polycarbonate, a high molecular polymer containing carbonate groups in its molecular chain, and is classified into various types such as aliphatic, aromatic, aliphatic-aromatic, and the like, depending on the structure of the ester groups.

"PPSU" is a polyphenylene sulfone resin, an amorphous thermoplastic, with high transparency and high hydrolytic stability.

"PES" is polyethersulfone, usually amorphous polymer, which has better melt processability and lower melt viscosity, smaller molding shrinkage (only about 0.6%), and better dimensional stability than polysulfone.

"PEI" is polyetherimide, a super engineering plastic made of amorphous polyetherimides, has the best high temperature resistance and dimensional stability, chemical resistance, flame retardance, electrical property, high strength, high rigidity and the like, and can be widely applied to high temperature resistant terminals, IC bases, lighting equipment, FPCB (flexible printed circuit board), liquid conveying equipment, airplane internal parts, medical equipment, household appliances and the like.

"PS" is polystyrene and refers to a polymer synthesized from styrene monomer by free radical addition polymerization. It is a colorless and transparent thermoplastic plastic with a glass transition temperature higher than 100 ℃, and is often used for manufacturing various disposable containers and disposable foam lunch boxes and the like which need to bear the temperature of boiled water.

The PP is polypropylene, is thermoplastic synthetic resin with excellent performance, and is colorless translucent thermoplastic light general-purpose plastic. Has chemical resistance, heat resistance, electric insulation, high-strength mechanical property, good high-wear-resistance processing property and the like.

"fluorine-containing resin" is a thermoplastic resin containing fluorine atoms in its molecular structure. Has the characteristics of excellent high and low temperature resistance, dielectric property, chemical stability, weather resistance, incombustibility, non-adhesiveness, low friction coefficient and the like.

The PVDF is polyvinylidene fluoride, mainly refers to vinylidene fluoride homopolymer or a copolymer of vinylidene fluoride and other small amount of fluorine-containing vinyl monomers, has the characteristics of both fluorine-containing resin and general resin, and has special performances such as piezoelectric property, dielectric property, hot spot property and the like besides good chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance and ray radiation resistance.

"PA" is a polyamide resin, a polycondensation type high molecular compound having a-CONH structure in the molecule, and is usually obtained by polycondensation of a dibasic acid and a diamine. The most prominent advantage of polyamide resins is the extremely narrow range of softening points, unlike other thermoplastic resins, which have a gradual curing or softening process, which causes rapid curing at temperatures slightly below the melting point.

"PE" is polyethylene, a thermoplastic resin obtained by the polymerization of ethylene. In industry, copolymers of ethylene with small amounts of alpha-olefins are also included. The polyethylene is odorless and nontoxic, feels like wax, has excellent low-temperature resistance (the lowest use temperature can reach-100 ℃ to-70 ℃), has good chemical stability, and can resist the corrosion of most of acid and alkali (cannot resist acid with oxidation property).

PET is polyethylene terephthalate, also commonly known as polyester resin. It is the polycondensate of terephthalic acid and ethylene glycol, belongs to a crystalline saturated polyester, is a milky white or light yellow highly crystalline polymer, and has smooth and glossy surface. Creep resistance, fatigue resistance and friction resistance are good, abrasion is small, hardness is high, and the thermoplastic plastic has the highest toughness; the electric insulation performance is good, and the influence of temperature is small.

"PAN" is an acrylonitrile resin whose main monomer is acrylonitrile, which provides good gas barrier, chemical resistance and gas and odor retention properties. Such resins have moderate tensile strength, good impact resistance when modified or oriented with rubber, and can be processed by extrusion, injection molding, and thermoforming, among other means.

PVA is polyvinyl alcohol, is a water-soluble high-molecular polymer with wide application, and has the performance between that of plastic and rubber.

The PVC is polyvinyl chloride and is a high molecular material obtained by vinyl chloride through addition polymerization reaction.

The PU is polyurethane resin and is a polymer containing urethane groups (-NH-COO-) in the molecular structure.

"SEBS" is a polystyrene-polybutadiene-polystyrene triblock copolymer.

ABS is acrylonitrile-butadiene-styrene copolymer, and is a thermoplastic high polymer material with high strength, good toughness and easy processing and molding.

"PVDF" is polyvinylidene fluoride, a highly non-reactive thermoplastic fluoropolymer.

"PEG" is polyethylene glycol, also known as polyethylene oxide, and refers to a polymer of ethylene oxide.

PTT is polytrimethylene terephthalate which has the characteristics of terylene and chinlon.

"chalcogenide glass" is glass containing sulfide, selenide, antimonide as main components, and also includes chalcogenide compound glass containing oxide, and chalcogenide glass has high processing efficiency and can be precision press-molded.

DMAC is dimethyl acetamide, is an aprotic high-polarity solvent, has a slight ammonia smell and strong dissolving power, can be freely mixed and dissolved with water, aromatic compounds, esters, ketones, alcohols, ethers, benzene, trichloromethane and the like, can activate compound molecules, and is widely used as a solvent and a catalyst.

DMF is dimethylformamide, a colorless transparent liquid, can be mutually soluble with water and most organic solvents, and is a common solvent for chemical reaction.

"chalcogenide glass" means glass mainly composed of sulfide, selenide and antimonide, and includes chalcogenide compound glass containing oxide, and the chalcogenide glass has high processing efficiency, can be precision-pressed, and is improved by more than 10 times than diamond turning, and the raw material cost is 1/3 of germanium single crystal.

The germanate glass has germanate as main component, high RE solubility, high crystallization stability, high chemical stability and high infrared transmittance in near infrared band.

The tellurate glass has tellurate as main component and excellent infrared transmittance in visible light and infrared band.

The fluoride glass is glass containing fluorine element, and is composed of fluoberyllite, fluoroaluminate and fluozirconate laser glass according to chemical compositions. The light-transmitting material has the characteristics of good thermo-optical performance, extremely wide light-transmitting range from ultraviolet to middle infrared and the like.

"magnetic particle diameter", when the magnetic particle is a sphere, the magnetic particle diameter is the diameter of the sphere; when the magnetic particle is an aspherical body, the diameter of the magnetic particle is calculated when the volume of the aspherical body is equal to the volume of the spherical body.

"fiber diameter," which is the diameter of a circle when the fiber is of circular cross-section; when the fiber has a non-circular cross-section, the diameter calculated when the fiber diameter is such that the non-circular cross-sectional area equals the circular cross-sectional area.

"cross section", when the micro-nano magnetic composite particle is in a spherical structure, the cross section obtained by cross cutting along the diameter of the composite particle is shown as 32 in fig. 5 and 47 in fig. 8 through the spherical center of the micro-nano magnetic composite particle.

"host particle" refers to the largest proportion of the particle size distribution.

The application provides a preparation method of micro-nano magnetic composite particles with adjustable and controllable sizes and structures, which comprises the following steps:

In one embodiment, the micro-nano magnetic particles are selected from at least one of the following: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles;

In one embodiment, the substrate is selected from at least one of the following: polymer, glass and composite material using the same as substrate material;

preferably, the polymer is a thermoplastic polymer;

The micro-nano magnetic fiber comprises a core layer, wherein the core layer comprises magnetic particles and a base material, and the magnetic particles are distributed in the base material;

the magnetic particles are selected from one or more than two of the following: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles;

the substrate is selected from one or two of the following: polymer, glass and composite material using the same as base material.

In one embodiment, the micro-nano magnetic fiber of the present application, the metal magnetic particles may be selected from, but not limited to, gold magnetic particles, silver magnetic particles, ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles; the metal compound magnetic particles may be selected from, but are not limited to, metal oxide magnetic particles; the metal oxide magnetic particles may be selected from, but are not limited to, Fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles; the metal alloy magnetic particles can be selected from but not limited to nickel-cobalt alloy magnetic particles, iron-cobalt alloy magnetic particles, neodymium iron boron alloy (NdFeB) magnetic particles, samarium cobalt alloy (SmCo) magnetic particlesAnd (4) adding the active ingredients.

In a preferred embodiment, the magnetic particles of the micro-nano magnetic fiber of the present application may be selected from one or more of the following: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles, Fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles, neodymium iron boron alloy magnetic particles, samarium cobalt alloy magnetic particles, nickel cobalt alloy magnetic particles, and iron cobalt alloy magnetic particles.

In a specific embodiment, the micro-nano magnetic fiber of the present application, the polymer is selected from and not limited to one or more of the following: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether; the glass is selected from and not limited to one or more than two of the following: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

In a specific embodiment, the diameter of the magnetic particles of the micro-nano magnetic fiber of the present application is 0.005-250 μm, and may be, for example, 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 220 μm, 230 μm, and the like.

In a specific embodiment, the diameter of the micro-nano magnetic fiber is 0.01-3000 μm, preferably 50-1000 μm, and may be, for example, 0.01 μm, 1 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600 μm, 1700 μm, 1800 μm, 1900 μm, 2000 μm.

In a specific embodiment, the micro-nano magnetic fiber of this application, micro-nano magnetic fiber is the columnar structure, micro-nano magnetic fiber cross section shape does not have the restriction, can select from following one or more than two kinds: circular, triangular, rectangular, polygonal, irregular.

In one embodiment, the micro-nano magnetic fiber of the present application may be any axially invariant structure, such as a single-concentration magnetic particle doped structure, a multi-concentration magnetic particle doped structure, a cladding-containing structure, a cladding-free structure, a high-melting-point functional layer-containing structure, and the like. Wherein, the single concentration of the magnetic particles is doped, which means that only one concentration of the magnetic particles is uniformly distributed in the core layer. The 'multi-concentration magnetic particle doping' means that the mass percentage of the magnetic particles in various magnetic composite materials are not completely the same, so that the magnetic particles are doped in multiple concentrations in the micro-nano magnetic fiber.

In a specific embodiment, the micro-nano magnetic fiber of the present application, the core layer is a multilayer structure from inside to outside, in any one layer of the core layer, the magnetic particles are in the in-layer uniform distribution. The magnetic particles in each of the layers of the core layer have a mass percentage of 0.01wt.% to 75wt.%, preferably 1wt.% to 75wt.%, and may be, for example, 0.01wt.%, 0.1wt.%, 1wt.%, 5wt.%, 10wt.%, 20wt.%, 30wt.%, 40wt.%, 50wt.%, 51wt.%, 52wt.%, 53wt.%, 54wt.%, 55wt.%, 56wt.%, 57wt.%, 58wt.%, 59wt.%, 60wt.%, 61wt.%, 62wt.%, 63wt.%, 64wt.%, 65wt.%, 66wt.%, 67wt.%, 68wt.%, 69wt.%, 70wt.%, 71wt.%, 72wt.%, 73wt.%, 74wt.%, 75wt.%, etc.

In a specific embodiment, in the micro-nano magnetic fiber of the present application, compared with each layer in the multiple layers of the core layer, the mass percentage of the magnetic particles in two, three, four, five, or six layers may be different.

In a specific embodiment, the mass percentage of the magnetic particles in each of the plurality of layers of the core layer is gradually decreased from the inside to the outside as compared to each of the plurality of layers.

In a specific embodiment, the mass percentage of the magnetic particles in each of the plurality of layers of the core layer is gradually increased from the inside to the outside as compared to each of the plurality of layers.

In a specific embodiment, the micro-nano magnetic fiber of the present application, the cross section of the core layer is circular, rectangular, triangular or irregular, the cross section is divided into two, three, four, five, six, seven, eight, nine or ten or more regions, thereby the core layer is divided into two, three, four, five, six, seven, eight, nine or ten or more strip structures, in any one strip structure, the magnetic particles are in uniform distribution in the strip structure, and the mass percentage content of the magnetic particles in at least two strip structures is different.

In a specific embodiment, in the micro-nano magnetic fiber of the present application, the cross section of the core layer is circular, and the cross section is divided into two, three, four, five, six, or more than seven sector regions; preferably, the cross section is divided into two equal semicircular areas, so that the core layer is divided into two strip-shaped structures, the magnetic particles are uniformly distributed in each strip-shaped structure, and the mass percentages of the magnetic particles in the two strip-shaped structures are different.

In a specific embodiment, the micro-nano magnetic fiber of the present application, the cross section of the core layer is rectangular, and the cross section is divided into any two, three, four or five equal rectangular areas.

In a specific embodiment, the cross section of the core layer of the micro-nano magnetic fiber is triangular, and the cross section is divided into any two triangular areas. In a preferred embodiment, the triangle is an isosceles triangle, and the cross section is divided into any two equal triangular areas.

In a specific embodiment, the micro-nano magnetic fiber of the present application includes a core layer and a high-melting-point functional layer, wherein the core layer wraps the high-melting-point functional layer; the glass transition temperature and the melting point of the material of the high-melting-point functional layer are respectively higher than those of the material of the core layer, and the material of the high-melting-point functional layer is a fibrous material or a material capable of being processed into a fibrous state, for example, a quartz optical fiber or a metal semiconductor can be used.

In a specific embodiment, the micro-nano magnetic fiber of the present application includes a core layer and a cladding layer, where the material of the cladding layer and the material of the core layer can be hot-drawn together, and the cladding layer wraps the core layer; the thermal expansion coefficient of the material of the cladding layer is the same as that of the material of the core layer; alternatively, the glass transition temperature and the melting point of the material of the cladding layer are lower than the glass transition temperature and the melting point of the material of the core layer, respectively.

In a specific embodiment, the micro-nano magnetic fiber of the present application includes a core layer, a cladding layer, and a high melting point functional layer, wherein the core layer wraps the high melting point functional layer, and the cladding layer wraps the core layer; co-thermal drawable of the material of the cladding layer and the material of the core layer; the thermal expansion coefficient of the material of the cladding layer is the same as that of the material of the core layer; alternatively, the glass transition temperature and the melting point of the material of the cladding layer are lower than the glass transition temperature and the melting point of the material of the core layer, respectively.

In one embodiment, the material of the cladding of the micro-nano magnetic fiber of the present application may be selected from one or more of the following polymers: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether; the cladding material may also be selected from one or more than two of the following glasses: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

In one embodiment, the micro-nano magnetic fiber of the present application includes a core layer and a cladding layer, wherein the cladding layer wraps the core layer; the core layer comprises two, three, four, five, six or more than seven discrete strip-shaped structures, and the two, three, four, five, six or more than seven strip-shaped structures are mutually discrete, namely, two strip-shaped structures are not contacted with each other.

In the above specific embodiment, the cross section of the micro-nano magnetic fiber may be circular, triangular, rectangular, or irregular.

In a specific embodiment, in the micro-nano magnetic fiber of the present application, the mass percentages of the magnetic particles in the discrete strip-shaped structures are not completely the same.

In a specific embodiment, in any one of the micro-nano magnetic fibers of the present application, the mass percentage of the magnetic particles in the stripe structure of the core material is 0.01wt.% to 75wt.%, preferably 1wt.% to 75wt.%, and may be, for example, 0.01wt.%, 0.1wt.%, 1wt.%, 5wt.%, 10wt.%, 20wt.%, 30wt.%, 40wt.%, 50wt.%, 51wt.%, 52wt.%, 53wt.%, 54wt.%, 55wt.%, 56wt.%, 57wt.%, 58wt.%, 59wt.%, 60wt.%, 61wt.%, 62wt.%, 63wt.%, 64wt.%, 65wt.%, 66wt.%, 67wt.%, 68wt.%, 69wt.%, 70wt.%, 71wt.%, 72wt.%, 73wt.%, 74wt.%, 75wt.%, or the like.

In a preferred embodiment of the present application, the micro-nano magnetic fiber includes a core layer, and the preparation method of the micro-nano magnetic fiber includes the following steps:

compounding: compounding the magnetic particles with a base material to obtain a magnetic composite material;

processing: preparing a magnetic structured preform from the magnetic composite material;

hot drawing: and preparing the magnetic structured prefabricated rod into the micro-nano magnetic fiber by adopting a hot drawing process.

In one embodiment, in the method of the present application, in the compounding step, the magnetic particles are compounded with the base material to obtain a plurality of magnetic composite materials, the base material for preparing each magnetic composite material may be different, and the doping concentration of the magnetic particles (the mass percentage of the magnetic particles in the magnetic composite material) may be different or the same between every two magnetic composite materials; in the processing step, the plurality of magnetic composite materials are used for directly preparing the magnetic structured prefabricated rod, or the plurality of magnetic composite materials are used for respectively preparing a plurality of prefabricated rods, and then the plurality of prefabricated rods are used for preparing the structured prefabricated rod.

In the above embodiments, the mass percentage of the magnetic particles in each of the magnetic composites in the method of the present application may be different or the same in the range of 0.01wt.% to 75wt.%, for example, 0.01wt.%, 0.1wt.%, 1wt.%, 5wt.%, 10wt.%, 20wt.%, 30wt.%, 40wt.%, 50wt.%, 51wt.%, 52wt.%, 53wt.%, 54wt.%, 55wt.%, 56wt.%, 57wt.%, 58wt.%, 59wt.%, 60wt.%, 61wt.%, 62wt.%, 63wt.%, 64wt.%, 65wt.%, 66wt.%, 67wt.%, 68wt.%, 69wt.%, 70wt.%, 71wt.%, 72wt.%, 73wt.%, 74wt.%, 75wt.%, etc.

In one embodiment, in the method of the present application, in the compounding step, the magnetic particles and the substrate are uniformly compounded by using a chemical method or a physical method or a combination of the chemical method and the physical method to obtain the magnetic composite particles, the magnetic composite film or the magnetic composite powder.

In one embodiment, the chemical process of the present application comprises the steps of:

(1) chemically dissolving the substrate using a solvent;

(2) doping the magnetic particles into the substrate;

(3) and ultrasonically stirring and dispersing the base material doped with the magnetic particles to obtain a colloidal solution.

In a preferred embodiment of the above embodiment, after obtaining the colloidal solution, the chemical process further comprises: and (4) drying in vacuum to obtain the magnetic composite material.

In a specific embodiment, the solvent may be selected from, but is not limited to, acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene solvent, ethyl acetate, butyl acetate, ethyl acetate, hydrofluoric acid, alkali metal hydroxide solution.

In one embodiment, the method of the present application, the physical method comprises the steps of:

(1) physically thermofusing the polymer, i.e., processing the polymer above the glass transition temperature, thereby effectively mixing the polymers at the molecular level;

(2) doping said magnetic particles into said hot molten polymer to form a mixture;

(3) the mixture is extruded at a pressure, speed and shape to form a magnetic composite.

In one embodiment, the obtained magnetic composite material can be uniformly spread to form a film, namely the magnetic composite material film, and the film-state composite material can be directly used for processing a magnetic structured preform. In a preferred embodiment, in order to ensure the doping uniformity of the magnetic particles in the magnetic structured preform, the magnetic composite material thin film can be mechanically broken into particles or powder by a crusher, so as to obtain the magnetic composite material particles or magnetic composite material powder, respectively, which is then used for processing the magnetic structured preform.

In a preferred embodiment, the magnetic composite thin film is obtained using the chemical method. The chemical method results in more uniform doping of the magnetic particles than the physical method.

In one embodiment, the magnetic particles are uniformly compounded with the substrate by a combination of chemical and physical methods, and the magnetic particles are more uniformly doped than by physical methods. The method combining the chemical method and the physical method comprises the following steps:

(1) chemically dissolving the substrate using a solvent;

(2) doping the magnetic particles into the substrate;

(4) And drying the colloidal solution in vacuum to obtain a solid material.

(5) The solid material is heated to a temperature above the glass transition temperature and extruded at a certain pressure, speed and shape to form the magnetic composite material.

In one embodiment, the polymer is selected from, and is not limited to, one or two or more of the following: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether; the glass is selected from and not limited to one or more than two of the following: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

In one embodiment, the present inventionThe method of, wherein the magnetic particles are selected from one or more of: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles; preferably, the metal magnetic particles may be selected from, but not limited to, ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles; the metal compound magnetic particles may be selected from, but are not limited to, metal oxide magnetic particles; the metal oxide magnetic particles may be selected from, but are not limited to, Fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles; the metal alloy magnetic particles may be selected from, but are not limited to, nickel-cobalt alloy magnetic particles, iron-cobalt alloy magnetic particles, neodymium-iron-boron alloy (NdFeB) magnetic particles, samarium-cobalt alloy (SmCo) magnetic particles.

In a preferred embodiment, in the method of the present application, the magnetic particles may be selected from one or two or more of: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles, Fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles, neodymium iron boron alloy magnetic particles, samarium cobalt alloy magnetic particles, nickel cobalt alloy magnetic particles, and iron cobalt alloy magnetic particles.

In a specific embodiment, according to the method of the present application, the magnetic particle diameter is 0.005-250 μm, and may be, for example, 0.005 μm, 0.01 μm, 0.05 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 210 μm, 220 μm, 230 μm, and the like.

In a specific embodiment, the method of the present application, the micro-nano magnetic fiber comprises a core layer, and in the processing step, the magnetic composite material is used to prepare the magnetic structured preform, wherein the magnetic composite material may be one or more, the base materials of the plurality of magnetic composite materials may be different or the same, and the mass percentage content of the contained magnetic particles may be different or the same between two of the plurality of magnetic composite materials. The magnetic composite material finally forms a core layer in the micro-nano magnetic fiber.

In a specific embodiment, the method of the present application, the micro-nano magnetic fiber comprises a core layer and a cladding layer, and in the processing step, the magnetic structured preform is prepared from the magnetic composite material and the cladding layer, wherein the magnetic composite material may be one or more, the base materials of the plurality of magnetic composite materials may be different or the same, and the mass percentage content of the contained magnetic particles may be different or the same between two of the plurality of magnetic composite materials. The magnetic composite material is used for forming a core layer in the micro-nano magnetic fiber, and the material of the cladding is used for forming the cladding in the micro-nano magnetic fiber. The coefficient of thermal expansion of the material of the cladding matches the coefficient of thermal expansion of the magnetic composite material; alternatively, the glass transition temperature or melting point of the material of the cladding is lower than the glass transition temperature or melting point, respectively, of the magnetic composite material. Specifically, the cladding comprises a base material selected from one or two of the following: polymers, glass; the polymer may be selected from, but is not limited to, one or two or more of the following: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether; the glass can be selected from but not limited to one or more than two of the following: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

In one embodiment, the cladding comprises magnetic particles and a substrate, and the magnetic particles are composited with the substrate to obtain the material of the cladding. The compounding method is the same as that for preparing the magnetic composite material.

In a specific embodiment, the coating comprises only the substrate and no magnetic particles.

In this application, when the magnetic micro-nanofiber has a cladding, the cladding is a layer on which magnetic particles are dispersed or does not contain the magnetic particles. The core layer is one or more layers which are wrapped by the cladding layer and contain magnetic particles.

In a specific implementation mode, the method of this application, micro-nano magnetic fiber includes sandwich layer and high melting point functional layer, in the hot drawing step, the cladding of magnetism structural preform the material of high melting point functional layer, and with the material machinery of high melting point functional layer adopts hot drawing technology preparation in step micro-nano magnetic fiber realizes that hot drawing makes the cladding of micro-nano magnetic fiber in-process to high melting point functional layer material. The glass transition temperature and the melting point of the material of the high-melting-point functional layer are respectively higher than those of the magnetic composite material, and the material of the high-melting-point functional layer is a fibrous material or a material capable of being processed into a fibrous state, such as a quartz optical fiber, a metal electrode, a semiconductor material, and the like. The material of the high-melting-point functional layer is used for forming the high-melting-point functional layer.

In a specific embodiment, in the method of the present application, the micro-nano magnetic fiber includes a core layer, a cladding layer and a high-melting-point functional layer, and in the processing step, the magnetic structured preform is prepared by using the magnetic composite material and the material of the cladding layer, wherein the magnetic composite material may be one or more, the base materials of the plurality of magnetic composite materials may be different or the same, and the mass percentage content of the magnetic particles contained in the plurality of magnetic composite materials may be different or the same between two magnetic composite materials; in the hot drawing step, the magnetic structural prefabricated rod wraps the material of the high-melting-point functional layer, and the micro-nano magnetic fiber is prepared by adopting a hot drawing process in mechanical synchronization with the material of the high-melting-point functional layer. The magnetic composite material is used for forming a core layer in the micro-nano magnetic fiber, and the material of the cladding is used for forming the cladding in the micro-nano magnetic fiber; the material of the high-melting-point functional layer is used for forming the high-melting-point functional layer.

In one embodiment, the method of the present application, wherein the processing step, the magnetically structured preform is prepared using one or more of a film winding method, a thermal pressing method, an extrusion molding method, and a 3D printing method; further, the method can also comprise one or more than two methods as follows: machining, assembling and thermosetting.

In a specific embodiment, in the method of the present application, the magnetic composite material is one or more than two magnetic composite material thin films, and the magnetic structured preform is processed by a thin film winding method, first, one magnetic composite material thin film is subjected to hot pressing and mechanical processing to obtain a columnar original preform, then, other magnetic composite material thin films are sequentially wound on the original preform, the other magnetic composite material thin films respectively form a preform, and then, each preform is subjected to thermosetting treatment to obtain a final magnetic structured preform. The Young's modulus of each of the magnetic composite material thin films is 0.01 to 1GPa, and may be, for example, 0.01GPa, 0.02GPa, 0.03GPa, 0.04GPa, 0.05GPa, 0.06GPa, 0.07GPa, 0.08GPa, 0.09GPa, 0.1GPa, 0.15GPa, 0.2GPa, 0.25GPa, 0.3GPa, 0.35GPa, 0.4GPa, 0.45GPa, 0.5GPa, 0.55GPa, 0.6GPa, 0.65GPa, 0.75GPa, 0.8GPa, 0.85GPa, 0.9GPa, 0.95GPa, or 1 GPa.

The hot pressing method is a method of molding and sintering a material such as a magnetic composite material into a preform under heating and simultaneously pressurizing conditions. In one embodiment, the method of the present application utilizes a hot pressing process to process a magnetically structured preform. According to the arrangement of the hot pressing mold, the magnetic composite material can be pressed into various shapes, one prefabricated rod is pressed each time, and the magnetic structural prefabricated rod can be prepared for different prefabricated rods by utilizing a mechanical processing method and an assembly method. Specifically, the mechanical processing method can cut the rectangular preform into a cylindrical or annular preform. More specifically, the cylindrical preform and the annular preform can be used for preparing the magnetic structured preform by an assembly method. Alternatively, the preform rod of different shape cut by the mechanical processing may be used in other methods such as a film winding method, an extrusion molding method, and a 3D printing method. Wherein the hot pressing temperature is not lower than the glass transition temperature or the melting point of the magnetic composite material, the hot pressing temperature is 25-600 ℃, preferably 120-250 ℃, and can be, for example, 25 ℃, 35 ℃, 45 ℃, 55 ℃, 65 ℃, 75 ℃, 85 ℃, 95 ℃, 105 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, 225 ℃, 230 ℃, 235 ℃, 240 ℃, 245 ℃ and 250 ℃; the hot pressing time is 5-600 min, preferably 10-20 min, for example, 5min, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, 25min, 30min, 35min, 50min, 60min, 70min, 80min, 90min, 100min, 120min, 140min, 180min, 22min, 260min, 300min, 340min, 380min, 420min, 460min, 500min, 600 min.

"extrusion molding" is a method of preparing a preform by placing a material in a mold and then molding it through a hole mold by strong extrusion. In one embodiment, the method of the present application utilizes an extrusion process to process a magnetically structured preform. Optionally, in the present application, a plurality of magnetic composite materials may be placed in one mold, and a magnetic structured preform containing a plurality of magnetic composite materials may be directly extruded; the magnetic composite material can be put into a mould respectively to be extruded into different prefabricated rods, and then the prefabricated rods are used for preparing the final magnetic structural prefabricated rod by one or two or three of an assembling method, a thermosetting method and a mechanical processing method. Wherein the extrusion temperature is not lower than the glass transition temperature or the melting point of the magnetic composite material, the extrusion temperature is 50-700 ℃, preferably 200-400 ℃, and can be, for example, 50 ℃, 70 ℃, 90 ℃, 110 ℃, 130 ℃, 150 ℃, 170 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 500 ℃, 600 ℃ and 700 ℃.

The "3D printing method" is a method of rapidly constructing an object by layer-by-layer printing using an adhesive material based on a digital model file. In one embodiment, the method of the present application, the magnetically structured preform is directly processed using a 3D printing method. In another embodiment, after the preform is processed by 3D printing, other methods such as film winding, thermal compaction, extrusion may be used to produce the final magnetically structured preform.

In a specific embodiment, the micro-nano magnetic fiber includes a core layer, the micro-nano magnetic fiber obtained in the hot drawing step can be used as a fibrous structured magnetic composite material, and a 3D printing method is used for performing secondary processing and secondary hot drawing, specifically, the method includes the following steps:

processing: preparing the magnetic structured prefabricated rod by one or more than two methods of a film winding method, a hot pressing method, an extrusion forming method and a 3D printing method;

hot drawing: preparing micro-nano magnetic fibers from the magnetic structured preform by adopting a hot drawing process;

secondary processing: preparing a second magnetic structured preform by using the micro-nano magnetic fiber through the 3D printing method;

secondary hot drawing: and preparing the second magnetic structured preform rod into the second micro-nano magnetic fiber by adopting a hot drawing process.

In an optional implementation manner of the above specific implementation manner, the micro-nano magnetic fiber two includes a cladding two, and in the secondary processing step, the magnetic structured preform two is prepared by using materials of the micro-nano magnetic fiber and the cladding two through a 3D printing method;

in an optional implementation manner of the foregoing specific embodiment, the micro-nano magnetic fiber two includes a second high-melting-point functional layer, and the second magnetic structured preform coats the material of the second high-melting-point functional layer, and the micro-nano magnetic fiber two and the material of the second high-melting-point functional layer are mechanically and synchronously prepared by a hot drawing process.

In a specific embodiment, the printing temperature of the 3D printing method for preparing the magnetic structured preform in the processing step and the printing temperature of the 3D printing method for preparing the magnetic structured preform in the secondary processing step are not lower than the glass transition temperature or the melting point of the magnetic composite material; the printing temperature is 50-700 deg.C, preferably 200-400 deg.C, such as 50 deg.C, 70 deg.C, 90 deg.C, 110 deg.C, 130 deg.C, 150 deg.C, 170 deg.C, 190 deg.C, 200 deg.C, 210 deg.C, 220 deg.C, 230 deg.C, 240 deg.C, 250 deg.C, 260 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C, 310 deg.C, 320 deg.C, 330 deg.C, 340 deg.C, 350 deg.C, 360 deg.C, 370 deg.C, 380 deg.C, 390 deg.C, 400 deg.C, 500 deg.C, 600 deg.C, 700 deg.C.

The "thermosetting method" is a method of curing the binder system by changing the energy of the molecules, and in this application means that the final magnetic structured preform is prepared by heating and curing between different preforms. In one embodiment, in the method of the present application, in the processing step, the curing temperature of the thermal curing method is not lower than the glass transition temperature or the melting point of the magnetic composite material; the curing temperature is 50-500 ℃, preferably 150-300 ℃, for example 50 ℃, 70 ℃, 90 ℃, 110 ℃, 130 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 450 ℃ and 500 ℃; the curing time is 1-500 min, preferably 20-40 min, and can be, for example, 1min, 5min, 10min, 15min, 20min, 22min, 24min, 26min, 28min, 30min, 32min, 34min, 36min, 38min, 40min, 100min, 130min, 160min, 190min, 220min, 250min, 280min, 310min, 340min, 370min, 400min, 430min, 460min, 490min, 500 min.

In one embodiment, the substrate, the magnetic composite material and the micro-nano magnetic fiber are dried in vacuum before use; the vacuum drying temperature is 20-300 deg.C, preferably 60-150 deg.C, such as 20 deg.C, 30 deg.C, 40 deg.C, 50 deg.C, 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, 100 deg.C, 110 deg.C, 120 deg.C, 130 deg.C, 140 deg.C, 150 deg.C, 160 deg.C, 170 deg.C, 180 deg.C, 190 deg.C, 200 deg.C, 210 deg.C, 220 deg.C, 230 deg.C, 240 deg.C, 250 deg.C, 260 deg.C, 280 deg.C, 290 deg.C, 300 deg.C etc.; the vacuum drying time is 2-2000 h, preferably 12-50 h, and can be, for example, 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h, 48h, 50h, 60h, 80h, 100h, 300h, 500h, 700h, 1000h, 1200h, 1400h, 4600h, 1800h, 2000h, and the like.

In one embodiment, the method of the present application, the temperature of the hot drawing process is 25 to 600 ℃, preferably 230 to 400 ℃, and may be, for example, 25 ℃, 50 ℃, 75 ℃, 100 ℃, 125 ℃, 150 ℃, 175 ℃, 200 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃; the tension of the hot drawing process is 0-500 g, preferably 10-50 g, for example, 0g, 2g, 4g, 6g, 8g, 10g, 12g, 14g, 16g, 18g, 20g, 22g, 24g, 26g, 28g, 30g, 32g, 34g, 36g, 38g, 40g, 42g, 44g, 46g, 48g, 50g, 100g, 150g, 200g, 250g, 300g, 350g, 400g, 450g, 500 g; the drawing speed of the thermal drawing process is 0.1m/min to 5000m/min, and can be, for example, 0.1m/min, 1m/min, 10m/min, 100m/min, 300m/min, 500m/min, 700m/min, 900m/min, 1000m/min, 2000m/min, 3000m/min, 4000m/min, or 5000 m/min.

In a specific embodiment, in the method of the present application, the structure of the micro-nano magnetic fiber is determined by the structure of the magnetic structured preform. The structures of the magnetic structured prefabricated rod and the micro-nano magnetic fiber are not limited, and the structures of the magnetic structured prefabricated rod and the micro-nano magnetic fiber are consistent along the axial direction of the fiber. The structure can be any axial invariant structure, more specifically, according to the distribution of the magnetic particle concentration, the structure can be a single-concentration magnetic particle doping structure or a multi-concentration magnetic particle doping structure; according to the existence of the cladding, the structure can be divided into a cladding structure and a non-cladding structure; the structure may also be a structure containing a high melting point functional layer, and the like.

In one embodiment, wherein the fluidization treatment is selected from at least one of: heat treatment and chemical treatment.

The heating treatment may be performed in a manner known to those skilled in the art, for example, the integral heating may be performed on the micro-nano magnetic fiber or the micro-nano magnetic fiber may be locally heated, for example, the integral heating manner may include a heating table heating manner, a heating furnace heating manner, and the like, and the integral heating manner may be performed on the micro-nano magnetic fiber; the local heating mode comprises a mode of local heating on the micro-nano magnetic fiber by local flame heating, laser heating and the like.

Preferably, the heating treatment temperature is 60-500 ℃, and more preferably 200-300 ℃; preferably, the heating time is 1s-24h, more preferably 30 min-2 h. As for the heating temperature, it varies depending on the glass transition temperature of the material in the magnetic fiber as long as the temperature is higher than the glass transition temperature of the material, and the heating time varies depending on the temperature.

For example, the heat treatment temperature may be 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃, 310 ℃, 320 ℃, 330 ℃, 340 ℃, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 410 ℃, 420 ℃, 430 ℃, 440 ℃, 450 ℃, 460 ℃, 470 ℃, 480 ℃, 490 ℃, 500 ℃ or the like.

The heating time can be 1s, 30s, 60s, 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45 min, 50min, 55 min, 60min, 1.5 h, 2h, 2.5 h, 3 h, 4h, 5 h, 6h, 7 h, 8h, 9 h, 10h, 11 h, 12h, 13 h, 14h, 15 h, 16h, 17 h, 18h, 19 h, 20h, 21 h, 22h, 23 h, 24h and the like.

The chemical treatment refers to a chemical treatment performed in a specific solvent, in which the temperature is higher than the glass transition temperature of the magnetic fiber material but lower than the thermal decomposition temperature of the reagent, and any temperature therebetween, and the treatment time varies depending on the temperature.

In a specific embodiment, the micro-nano magnetic fiber is wound on a glass tube, two ends of the micro-nano magnetic fiber are fixed, and the micro-nano magnetic fiber is placed in a muffle furnace for heating treatment.

In the heating method, the micro-nano magnetic fiber undergoes a sine state and a spherical state.

In a specific embodiment, after the fluidization treatment, the method further includes directionally dissolving the fiber cladding of the fluidized micro-nano magnetic fiber by using a chemical solvent to obtain the micro-nano magnetic composite particles.

In one embodiment, the chemical solvent is a polar solvent or a non-polar solvent, and preferably, the chemical solvent is selected from at least one of the following: acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene solvent, ethyl acetate, butyl acetate, hydrofluoric acid, alkali metal oxides.

In a specific embodiment, after the fluidizing treatment, the method further includes performing extrusion treatment on the fluidized micro-nano magnetic fibers while maintaining the glass transition temperature of the substrate, so that the substrate is permanently deformed under the extrusion action, and preferably, after the extrusion treatment, directionally dissolving the fiber cladding of the extruded micro-nano magnetic fibers by using a chemical solvent, so as to obtain the micro-nano magnetic composite particles.

In a specific embodiment, the fluidization treatment is to fluidize the micro-nano magnetic fiber in a chemical solvent atmosphere, preferably to fluidize the micro-nano magnetic fiber in a chemical solvent or in a chemical solvent vapor. The chemical solvent may be a polar solvent or a non-polar solvent, and preferably, the chemical solvent is selected from at least one of the following: acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene solvent, ethyl acetate, butyl acetate, hydrofluoric acid, alkali metal oxides.

In one embodiment, the number of particles produced is in the range of 2 to 1000000000 particles/cm per cm of size.

In one embodiment, wherein the size error of the magnetic composite particles is in the range of + - (+ -.) (0.1-10%) of the major particle size.

The application provides a micro-nano magnetic composite particle with adjustable size and structure, wherein the micro-nano magnetic composite particle is prepared by the method.

The application provides micro-nano magnetic composite particles with adjustable size and structure, which comprise micro-nano magnetic particles and a base material,

the weight percentage of the micro-nano magnetic particles based on the total weight of the micro-nano magnetic composite particles is 0.01wt.% to 75wt.%, preferably 1wt.% to 75wt.%, and may be, for example, 0.01wt.%, 0.1wt.%, 1wt.%, 5wt.%, 10wt.%, 20wt.%, 30wt.%, 40wt.%, 50wt.%, 51wt.%, 52wt.%, 53wt.%, 54wt.%, 55wt.%, 56wt.%, 57wt.%, 58wt.%, 59wt.%, 60wt.%, 61wt.%, 62wt.%, 63wt.%, 64wt.%, 65wt.%, 66wt.%, 67wt.%, 68wt.%, 69wt.%, 70wt.%, 71wt.%, 72wt.%, 73wt.%, 74wt.%, 75wt.%, and the like.

preferably, the substrate is selected from at least one of the following: polymer, glass and composite materials using the polymer and the glass as substrates.

In one embodiment, wherein the polymer is a thermoplastic polymer; preferably, the thermoplastic polymer may be at least one of: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether.

In a specific embodiment, the glass is one of chalcogenide glass, germanate glass, tellurate glass, metal oxide glass and fluoride glass, or any combination thereof.

In a specific embodiment, the metal magnetic particles are selected from one or more of the following: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles;

In one embodiment, the micro-nano magnetic particles are uniformly distributed in the matrix.

In a specific embodiment, the structure of the micro-nano magnetic composite particles may be a spherical structure, a double-spherical structure, a wrapped structure, a shuttle-type structure, a flat structure, a fried egg-type structure, or a combination thereof.

The structure of the micro-nano magnetic composite particles can be a combined structure based on a spherical shape, a double-spherical shape, a wrapped shape, a fusiform shape, a flat shape, a rod shape, a ring shape and a fried egg shape.

In a specific embodiment, the micro-nano magnetic composite particles are spherical structures, preferably core-shell structures, wherein the mass percentage of the micro-nano magnetic particles in the core in the base material is different from the mass percentage of the micro-nano magnetic particles in the shell in the base material, such as gradually decreasing, gradually increasing or non-monotone changing;

preferably, in the micro-nano magnetic composite particles, the mass percentage of the micro-magnetic particles in the corresponding base material is gradually reduced along the core-shell direction.

In a specific embodiment, the micro-nano magnetic composite particle comprises n shell structures, wherein n is an integer greater than or equal to 1, for example, n can be 2,3,4, and the like; preferably, in the core-shell structure, the mass percentages of the micro-nano magnetic particles in at least two shell structures are different, for example, gradually decreasing or gradually increasing or non-monotonously changing.

In a specific embodiment, the micro-nano magnetic particles gradually decrease in mass percentage from inside to outside in the shell structure.

In a specific embodiment, the micro-nano magnetic composite particles are of a spherical structure, wherein a cross section obtained by transversely cutting the micro-nano magnetic composite particles along the diameter of the composite particles through the spherical centers of the micro-nano magnetic composite particles, two radii of the cross section and arcs thereof divide the cross section into different parts, and the micro-nano magnetic particles in the different parts have different mass percentages.

In a specific embodiment, the two radii of the cross section and the arc thereof divide the cross section into two equal parts, and the two parts have different mass percentages of the micro-nano magnetic particles.

In a specific embodiment, the micro-nano magnetic composite particle further comprises a metal wire, and the metal wire penetrates through the micro-nano magnetic composite particle.

The wire may be a wire known to those skilled in the art, such as a stainless steel wire.

In a specific embodiment, the micro-nano magnetic composite particles are of a double-sphere structure, and the weight percentages of the micro-nano magnetic particles in the double-sphere structure are different or the same.

In one embodiment, the color depth in the micro-nano magnetic composite particles obtained in fig. 2 to 13 is used to indicate the doping concentration of the magnetic particles, for example, the color depth may indicate that the doping concentration of the magnetic particles is high or low or the same, and the color depth may also indicate that the doping concentration of the magnetic particles is high or low or the same.

The invention provides the application of the micro-nano magnetic composite particles or the micro-nano magnetic composite particles prepared by the preparation method in biomedical materials.

According to the invention, the fluid instability of the fiber-state magnetic composite material is triggered through the regulation of temperature or a chemical reagent, in-situ discrete micro-nano magnetic polymer particle groups are formed in the fiber, the magnetic fiber cladding is directionally dissolved through a proper chemical solvent, the micro-nano magnetic composite particles are released (the particles can be directly collected by the magnetic fiber without the cladding structure), and the magnetic particles are collected, so that the high-flux micro-nano magnetic polymer particle groups with highly-assimilable structures and sizes are obtained.

The invention is described generally and/or specifically for the materials used in the tests and the test methods, in the following examples,% means wt%, i.e. percent by weight, unless otherwise specified. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.

Table 1 sources of raw materials used in the examples

EXAMPLE 1 preparation of mononuclear micron magnetic particles

(1) Preparation of micron magnetic fiber

The polymer is cycloolefin copolymer (COC), and the magnetic particles are Fe₃O₄The nanoparticle specifically comprises the following steps:

taking 14g of dried cycloolefin copolymer (COC), dissolving in chloroform solvent, adding 6g of Fe₃O₄Stirring and ultrasonically treating the nano particles to obtain a uniformly mixed colloidal solution. Drying at normal temperature with high specific surface area, and vacuum drying to obtain Fe₃O₄The doping concentration of the magnetic composite material is 30 percent. The temperature of vacuum drying is 70 ℃, and the time is 24 h.

The Fe obtained above is added₃O₄The magnetic composite polymer with the nano particle doping concentration of 30 percent is processed by hot pressing and mechanical cold processing to obtain Fe₃O₄The magnetic preform with the nano particle doping concentration of 30% is round, the diameter of the magnetic preform is 6mm, the PMMA preform is subjected to hot pressing and mechanical cold machining, the preform is round and hollow, the inner diameter of the preform is 6mm, and the outer diameter of the preform is 30 mm. And mechanically combining the magnetic prefabricated rod and the hollow PMMA prefabricated rod, wherein the hot pressing temperature is 160 ℃, and the hot pressing time is 20min, so as to obtain the composite prefabricated rod.

Carrying out hot wire drawing on the obtained composite preform with the doping concentration of 30% to obtain Fe₃O₄The nano-particles are doped with micro-nano magnetic fibers with the concentration of 30%, and the diameter of the prepared micro-nano magnetic fibers is 500 mu m.

The cladding is PMMA polymer, the core is COC polymer, and the magnetic doped microparticle material is Fe₃O₄The magnetic fiber of the nano-particle has an outer diameter of 500 μm, a doping concentration of 30wt.%, and a core diameter of 100 μm.

(2) Fluidization treatment:

winding 10m of the micron magnetic fiber in the step (1) on a glass tube, fixing two ends of the glass tube, putting the glass tube into a heating furnace, heating at 240 ℃, taking out the glass tube after heating for 3min, and cooling to room temperature to obtain cladding medium-size highly-assimilated sinusoidal particles; then heating for 10min, taking out, and cooling to room temperature to obtain spherical particles with highly-assimilated size in the cladding.

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC solution to dissolve the coating, releasing a large amount of magnetic particles from the coating, filtering and washing the solution to obtain micron magnetic particles, wherein the preparation flow is shown in figure 2.

The particle was measured to have a diameter of 200 μm, the magnetic particles of 30wt.% were present in the magnetic particles, and the number of particles prepared was 20 per cm.

Example 2 high throughput parallel preparation of nano-magnetic particles

(1) Preparation of nano magnetic fiber

The base material is COC polymer, and the magnetic micron particle material is ferroferric oxide nano-particles. The method comprises the following steps:

20g of COC particles were added to 160 mL of chloroform solvent and stirred away from light until the particles were completely dissolved. And (3) mixing 20g of ferroferric oxide nano particles with the solution, stirring, and performing ultrasonic treatment for 30min to obtain a uniform solution. Drying for 48h, pulverizing into powder, placing in a cylindrical mold with diameter of 4mm, pressurizing at 170 deg.C under 15MPa for 15min, taking out, filling for several times, and hot-press molding to obtain magnetic polymer core;

then preparing a magnetic polymer prefabricated rod, winding a PMMA film with the thickness of 200 mu m outside a magnetic polymer core with the diameter of 4mm to obtain a single-core prefabricated rod with the inner diameter of 4mm and the outer diameter of 20 mm, and thermally setting at 210 ℃ for 15min to obtain the magnetic polymer prefabricated rod. The obtained magnetic polymer preform was hot-drawn at 350 ℃ to obtain a magnetic polymer fiber having an outer diameter of 100 μm.

Winding 100 magnetic polymer fibers to the outer diameter of 30mm by using a film, placing the magnetic polymer fibers in a muffle furnace, and thermally curing the magnetic polymer fibers at 210 ℃ for 15min to obtain a magnetic array polymer preform; and (3) performing rapid iterative thermal drawing on the obtained magnetic array polymer preform at 350 ℃ under the condition of negative pressure pumping of 1.3 kPa to obtain the magnetic polymer fiber with the outer diameter of 300 mu m.

Then, the PMMA film is used for winding, and then the thermosetting is carried out for 15min at 210 ℃, so as to obtain the magnetic fiber with the outer diameter of 300 mu m.

The cladding is PMMA polymer, the core is COC polymer, and the magnetic doped nano particle material is Fe₃O₄The outer diameter of the magnetic fiber of the nano-particle is 300 mu m, the doping concentration is 50wt%, and the diameter of the fiber core is 180 nm.

(2) Fluidization treatment:

winding the nano magnetic fiber of 10m in the step (1) on a glass tube, fixing two ends of the glass tube, putting the glass tube into a muffle furnace, heating the glass tube at 240 ℃, taking out the glass tube after heating for 3min, and cooling the glass tube to room temperature to obtain cladding medium-size highly-assimilated sinusoidal particles; and heating for 10min, taking out, and cooling to room temperature to obtain spherical particles with highly-assimilated size in the cladding.

(3) Release of the nano-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 400 mL of DMAC solution to dissolve the coating, releasing a large amount of nano-magnetic particles from the coating, and filtering and washing the solution to obtain the nano-magnetic particles, wherein the preparation flow is shown in figure 3.

The measurement shows that the diameter of the monodisperse particle is 400 nm, the proportion of the nano magnetic particles in the magnetic particles is 50wt.%, and the number of the prepared particles is 2000000 per centimeter.

Example 3 preparation of micro-magnetic particles with radially magnetically anisotropic Structure

(1) Preparation of micron magnetic fiber

The substrate is a COC polymer, and the magnetic micron particle material is neodymium iron boron micron particles.

The first step is the preparation of magnetic polymer materials with different concentrations, firstly, the magnetic polymer materials with 75wt.% concentration are prepared, 10g of COC particles are dried in a vacuum oven at 60 ℃ for 24h, 20 mL of chloroform solvent is added, and the mixture is stirred in a dark place until the particles are completely dissolved. And (3) mixing 30g of neodymium iron boron micron powder with the solution, stirring, and performing ultrasonic treatment for 15min to obtain a uniform solution. Drying the mixed solution for 48h, crushing into powder, drying in a 60 ℃ oven for 120 h, and removing the solvent chloroform to obtain 75wt.% of magnetic polymer material;

then preparing a magnetic polymer material with the concentration of 50wt.%, drying 20g of COC particles in a vacuum oven at 60 ℃ for 24h, adding 160 mL of chloroform solvent, and stirring in a dark place until the particles are completely dissolved. And (3) mixing 20g of neodymium iron boron micron powder with the solution, stirring, and performing ultrasonic treatment for 15min to obtain a uniform solution. Drying for 48h, and crushing into powder to obtain a magnetic polymer material with the concentration of 50 wt.%;

finally, preparing 1wt.% magnetic polymer material, drying 19.8 g of COC particles in a vacuum oven at 60 ℃ for 24h, adding 160 mL of chloroform solvent, and stirring in a dark place until the particles are completely dissolved. Mixing 0.2g of neodymium iron boron micron powder with the solution, stirring, performing ultrasonic treatment for 15min to obtain a uniform solution, drying for 48h, and crushing into powder to obtain the magnetic polymer material with the concentration of 1 wt.%.

And (3) hot-pressing the magnetic polymer powder with the concentration of 50wt.% and 1wt.% into a film at 170 ℃ and 15MPa to obtain the magnetic polymer film with uniform thickness.

Preparing a core layer, namely putting the magnetic polymer powder with the concentration of 75wt.% obtained in the first step into a cylindrical mold with the diameter of 4mm, pressurizing at 170 ℃ for 15MPa, taking out after 15min, filling for many times until hot press molding is carried out, and obtaining the magnetic polymer core;

then preparing magnetic polymer prefabricated rods with different concentrations, and sequentially winding magnetic polymer films with the concentrations of 50wt.% and 1wt.% outside the magnetic polymer cores to obtain the magnetic polymer cores with different concentrations, wherein the diameters of the magnetic polymer cores are 8 mm;

and finally, preparing a radial magnetic anisotropy structure magnetic polymer preform, carrying out hot pressing and polishing to prepare a PMMA hollow preform with the inner diameter of 8mm and the outer diameter of 24mm, and then mechanically combining the magnetic polymer cores with different concentrations and the hollow PMMA preform, wherein the hot pressing temperature is 160 ℃, and the hot pressing time is 20min, so as to obtain the composite preform.

The magnetic polymer composite prefabricated rod obtained by the method is hot-drawn at 350 ℃ to obtain the magnetic polymer fiber with the radial magnetic anisotropy structure and the outer diameter of 300 mu m, and the diameter of the fiber core is 100 mu m.

As shown in fig. 4, the darkest portion represents the magnetic polymer doped with 75wt.% of the ndfeb particles, with the doping concentrations decreasing in order as the color becomes lighter.

(2) Fluidization treatment:

winding 10m of the micron magnetic fiber in the step (1) on a glass tube, fixing two ends of the glass tube, putting the glass tube into a muffle furnace, heating the glass tube at 240 ℃, taking out the glass tube after heating for 3min, and cooling the glass tube to room temperature to obtain cladding medium-size highly-assimilated sinusoidal particles; and heating for 10min, taking out, and cooling to room temperature to obtain spherical particles with highly-assimilated size in the cladding.

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the preparation process is shown in FIG. 4, wherein in the magnetic fiber, the deepest part of the color represents a fiber core (magnetic polymer) doped with neodymium iron boron particles with the highest concentration (75 wt.%), and the doping concentration is reduced sequentially along with the lightening of the color.

The particles were determined to have a diameter of 200 μm, the proportion of the magnetic microparticles in the magnetic particles was up to 75wt.%, and then 50wt.% and 1wt.% in this order radially outward, and the number of particles prepared was 20 per cm.

Example 4 magnetic microparticles with azimuthal magnetic anisotropy Structure

(1) Preparation of micron magnetic fiber

Base materials with NdFeB doping concentrations of 75wt.% and 50wt.% were prepared according to the method described in example 3, respectively; then, preforms are prepared separately.

The magnetic preforms were each physically polished to a cross-section consistent with that shown in FIG. 5, and the combined diameter was 6 mm. The PMMA preform rod is round and hollow, the inner diameter is 6mm, and the outer diameter is 30 mm. And carrying out hot pressing on the combined prefabricated rod and the hollow PMMA prefabricated rod to obtain a composite prefabricated rod.

And then, hot-drawing the composite preform at 350 ℃ to obtain the magnetic polymer fiber with the radial magnetic anisotropy structure and the outer diameter of 300 mu m, wherein the diameter of the fiber core is 60 mu m.

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the fiber core part has different doping concentrations in the angle direction, the part with the deepest color represents a fiber core (magnetic polymer) doped with 75wt.% of neodymium iron boron particles, and the part with the shallower doping concentration represents a fiber core (magnetic polymer) doped with 50wt.% of neodymium iron boron particles.

The particle was measured to have a diameter of 120 μm, the darkest part of the magnetic particles in the micrometer magnetic particles represented 75wt.% doping, the lighter part represented 50wt.%, and the number of particles prepared was 40 per cm.

EXAMPLE 5 magnetic Structure of contact Assembly

(1) Preparation of micron magnetic fiber

Magnetic polymer cores with neodymium iron boron doping concentrations of 75wt.% and 50wt.% are prepared according to the method of example 3, and are respectively ground into cylinders with diameters of 10mm and 5mm by a physical cutting grinding method. Hot pressing at 160 ℃ for 20min to prepare PMMA, mechanically punching, respectively punching through holes with the inner diameters of 10mm and 5mm, and grinding the PMMA into a cylinder with the outer diameter of 50 mm. The magnetic polymer core is inserted and assembled into a prefabricated rod. And hot-drawing the magnetic polymer preform obtained by the method at 350 ℃ to obtain the magnetic polymer fiber with the radial magnetic anisotropy structure and the outer diameter of 500 mu m. As shown in fig. 6, the two cores are in intimate contact. The darkest part represents a magnetic polymer doped with 75wt.% neodymium iron boron particles, 100 μm in diameter; the shallower doped fraction represents 50wt.% of the magnetic polymer of neodymium iron boron particles, 50 μm in diameter.

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the preparation flow is shown in FIG. 6.

It was determined that in the particles having the structure shown in fig. 6, the diameter of the larger sphere is 200 μm, the diameter of the smaller sphere is 100 μm, and the ratio of the magnetic microparticles in the magnetic particles is: the darkest part represents the magnetic polymer doped with 75wt.% neodymium iron boron particles, the lighter part represents 50wt.%, and the number of particles prepared is 15 per cm.

Example 6 preparation of magnetic microparticles having a "sugarcoated haws string" structure

(1) Preparation of micron magnetic fiber

Taking 20g of dried cycloolefin copolymer (COC), dissolving in chloroform solvent, adding 5g of NdFe

A magnetic composite with a NdFeB doping concentration of 20wt.% was obtained. And carrying out hot pressing and mechanical cold processing to obtain a hollow magnetic structured preform with NdFeB doping concentration of 20wt.%, wherein the outer diameter is 6mm, and the inner diameter is 5 mm. A50 μm diameter wire was passed through the inner through-hole of the preform while hot-pressing to prepare a PMMA hollow preform having an outer diameter of 30mm and an inner diameter of 6 mm. The preform with the metal wire and the PMMA hollow preform were hot-drawn to prepare a fiber having a diameter of 300. mu.m. The outer diameter of the obtained magnetic fiber of the magnetic fiber is 300 μm, the doping concentration is 20wt.%, and the diameter of the fiber core is 60 μm.

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the preparation flow is shown in FIG. 7.

The particle diameter was determined to be 150 μm, the fraction of the magnetic microparticles in the magnetic particles was 20wt.%, the number of particles prepared was 20 per cm, and the particles were connected by a wire.

Example 7 preparation of magnetic microparticles with a "Janus" Structure

(1) Preparation of micron magnetic fiber

A preform having a cross-section as shown in fig. 8 was formed according to the method described in example 4 and a magnetic polymer fiber was prepared according to the method described in example 4. As shown in fig. 8, the darkest part represents the core doped with 75wt.% of ndfeb particles (the polymer base is COC), and the lighter part represents the core doped with 50wt.% of ndfeb particles (the polymer base is COC). The cladding is PMMA polymer, wherein the fiber core is of an asymmetric doping concentration structure, the magnetic doping micron particle material is neodymium iron boron micron particles, the outer diameter of the magnetic fiber is 1 mm, and the diameter of the fiber core is 500 microns.

(2) Fluidization treatment:

winding 10m of the micron magnetic fiber obtained in the step (1) on a glass tube, fixing two ends of the glass tube, putting the glass tube into a muffle furnace, heating the glass tube at 240 ℃, taking out the glass tube after heating for 3min, and cooling the glass tube to room temperature to obtain cladding medium-size highly-assimilated sinusoidal particles; and heating for 10min, taking out, and cooling to room temperature to obtain spherical particles with highly-assimilated size in the cladding.

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the preparation flow is shown in FIG. 8, the core part has asymmetric doping concentration, the part with the deepest color represents a fiber core (magnetic polymer) doped with 75wt.% of neodymium iron boron particles, and the part with the shallower doping concentration represents the fiber core (magnetic polymer) doped with 50wt.% of neodymium iron boron particles.

The particle diameter is measured to be 200 μm, and the proportion of the micron magnetic particles in the magnetic particles is as follows: the darkest part represents the doping 75wt.%, the lighter part represents 50wt.%, and the number of particles produced is 20 per cm.

Example 8 preparation of magnetic microparticles with two-dimensional code Structure

(1) Preparation of micron magnetic fiber

Forming a preform with a cross section as shown in fig. 9 according to the method of example 5, and then preparing a magnetic polymer fiber with the method of example 5, as shown in fig. 9, where the cladding is PMMA polymer, the core layer is COC polymer, the magnetic doped microparticle is ndfeb microparticles, and the diagonal distance of the cross section of the magnetic fiber is 500 μm, where the cross section of the magnetic fiber is a two-dimensional code structure, and the doping concentration is: the darker part is 60wt.%, the lighter part is 20wt.%, and the diagonal distance of the core cross-section is 100 μm.

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic polymer particles, wherein the preparation flow is shown in FIG. 9.

The particle diameter is measured to be 200 μm, and the proportion of the micron magnetic particles in the magnetic particles is as follows: the darker part was 60wt.%, the lighter part was 20wt.%, and the number of particles produced was 20 per cm.

Example 9 preparation of magnetic microparticles with triangular spindle Structure

(1) Preparation of micron magnetic fiber

A preform having a cross section as shown in fig. 10 was formed according to the method of example 4 and a magnetic fiber was prepared according to the method of example 4, wherein the cladding layer was PMMA polymer, the core layer material was COC polymer, the magnetic doped microparticle material was neodymium iron boron microparticles, and the outer diameter of the magnetic fiber was 100 μm. Wherein, the magnetic fiber cross section is the triangle-shaped structure, and the doping concentration is: the darker part is 60wt.%, the lighter part 20wt.%, and the core diameter is 20 μm.

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of DMAC (dimethylacetamide) for dissolving the coating, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles, wherein the preparation flow is shown in FIG. 10.

The particle diameter is measured to be 50 μm, and the proportion of the micron magnetic particles in the magnetic particles is as follows: the darker part was 60wt.%, the lighter part was 20wt.%, and the number of particles produced was 80 per cm.

Example 10 preparation of micro magnetic particles comprising a polymeric material and an inorganic glass material

(1) Preparation of micron magnetic fiber

Preparing 20g of PEI particles and 20g of ferroferric oxide nanoparticles, carrying out hot pressing at 210 ℃ for 10min by a hot pressing method after physical mixing to prepare a PEI preform doped with 50wt.% ferroferric oxide, and carrying out physical cutting and polishing to prepare a semi-cylindrical shape with the diameter of 6 mm. Semi-cylindrical As with a diameter of 6mm₂S₃The glass preform and the semi-cylindrical PEI polymer preform having a diameter of 6mm were combined into a cylindrical preform having a diameter of 6 mm. Preparing PES prefabricated rod by hot pressing at 200 ℃ for 10min through a hot pressing method, and physically cutting, polishing and drilling to obtain a hollow prefabricated rod with the outer diameter of 30mm and the inner diameter of 6 mm. A6 mm diameter preform was inserted into the hollow PES preform, and hot-drawn at 330 ℃ to obtain a fiber having an outer diameter of 100 μm and a core diameter of 20 μm.

The fiber structure is shown in fig. 8, the core part has asymmetric doping concentration, the darkest part represents the magnetic polymer doped with 50wt.% neodymium-iron-boron particles, and the lighter part represents As₂S₃And (3) glass.

(2) Fluidization treatment:

winding 10m of the micron magnetic fiber obtained in the step (1) on a glass tube, fixing two ends of the glass tube, putting the glass tube into a muffle furnace, heating the glass tube at 300 ℃, taking out the glass tube after heating for 3min, and cooling the glass tube to room temperature to obtain cladding medium-size highly-assimilated sinusoidal particles; and heating for 10min, taking out, and cooling to room temperature to obtain spherical particles with highly-assimilated size in the cladding.

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of acetone for coating dissolution, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic particles.

The particle was measured to have a diameter of 40 μm, the magnetic particles of 50wt.% were present in the magnetic particles, and the number of particles prepared was 200 per cm.

Example 11 preparation of micro-magnetic particles with glass shell

(1) Preparation of micron magnetic fiber

Core-doped magnetic microparticles, magnetic fiber with multiple claddings, hot-drawn temperature 340 ℃, PES polymer As the outermost cladding, As the second cladding, were prepared according to the method of example 3₂S₃The glass, the rest of the cladding layers are PEI polymer doped with magnetic particles, the fiber core is PEI polymer, the magnetic doped micron particle material is neodymium iron boron micron particles, the outer diameter of the magnetic fiber is 500 microns, and the diameter of the fiber core is 100 microns.

The fiber structure is shown in fig. 4, the darkest part represents PEI magnetic polymer doped with neodymium iron boron with the highest concentration (75 wt.%), and the outermost layer of the fiber core is undoped As₂S₃Glass material, the doping concentration decreases in order as the color becomes lighter (50 wt.% and 1 wt.%).

(2) Fluidization treatment:

(3) Release of micro-magnetic particles:

and (3) putting the spherical particles with highly-assimilated sizes in the coating in the step (2) into 200 mL of acetone for coating dissolution, releasing a large amount of magnetic particles from the coating, and filtering and washing the solution to obtain the magnetic polymer particles.

The particle diameter is measured to be 200 μm, and the proportion of the micron magnetic particles in the magnetic particles is as follows: the darkest part represents PEI magnetic polymer doped with NdFeB particles with the highest concentration (75 wt.%) and the outermost layer of the fiber core is undoped As₂S₃Glass material, the number of particles prepared is 20 per centimeter.

Example 12 preparation of micro magnetic particles having a flat shape

The fibers of example 1, which now contain particles as shown at 61 in FIG. 11, were placed between two glass plates. The glass plate was placed on a heating table and heated to the glass transition temperature (110 ℃) of the fiber material, and a 5g weight was placed on the upper glass plate, at which time the fibers were deformed by the pressure, as shown at 64, 65 in fig. 11. The timing was started when the temperature of the heating stage increased to the glass transition temperature of the fiber material, the weight was removed after 10 s and the heating stage was closed, the fiber between the two glass plates was taken out after cooling to room temperature, the cladding solvent in each of the above examples was selected to dissolve the cladding to obtain flat particles, and the preparation flow is shown in fig. 11.

The fibers obtained in examples 2 to 11 were each subjected to the method described in example 12 to give flat particles.

EXAMPLE 13 preparation of magnetic particles of omelet type

(1) Preparation of micron magnetic fiber

Magnetic fibers with PC cladding were prepared as described in example 1, where the PC hot pressing temperature was 190 ℃;

magnetic fibers with a cladding are placed on the glass substrate 67, wherein the cladding material is a PC polymer doped with ferroferric oxide magnetic particles, the core material is a PMMA polymer doped with ferroferric oxide magnetic particles, the fiber diameter is 500 μm, the core diameter is 100 μm, the doping concentration is 20wt.% of cladding doping, and the core doping is 50 wt.%.

(2) Fluidization treatment and release of micro-magnetic particles

The micron magnetic fiber is put into a beaker filled with toluene vapor, and the temperature is kept constant at 30 ℃. After 30 minutes, the glass substrate was taken out to obtain magnetic particles having a omelet-type structure, and the preparation process is shown in fig. 12.

The particle diameter is 200 μm, the proportion of the nano magnetic particles in the magnetic particle is 20wt.% of cladding doping, 50wt.% of core doping, and the number of the prepared particles is 20 per centimeter.

EXAMPLE 14 preparation of Ring-type magnetic particles

The magnetic particles of omelet type structure described in example 13 were placed in cyclohexane, and after stirring for 10 minutes, the PMMA polymer with magnetic particles doped in the middle was dissolved in cyclohexane, and the PC polymer with magnetic particles doped at the periphery was retained, to obtain ring-shaped magnetic particles, as shown in fig. 13.

The particle was measured to have a diameter of 200 μm and the proportion of nano-magnetic particles in the magnetic particles was 20 wt.%.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

carrying out fluidization treatment on the micro-nano magnetic fiber containing the micro-nano magnetic particles and the base material;

the fluidization treatment is heating treatment;

after the fluidization treatment, the fluidized micro-nano magnetic fibers are directionally dissolved in the fiber cladding by using a chemical solvent to obtain micro-nano magnetic composite particles;

the micro-nano magnetic composite particles comprise micro-nano magnetic particles and a base material;

the micro-nano magnetic particles are selected from at least one of the following substances: metal magnetic particles, metal compound magnetic particles, metal alloy magnetic particles;

the substrate is selected from at least one of the following: polymers and inorganic glass materials;

the micro-nano magnetic composite particles are of a core-shell structure, and the mass percentage of the micro-nano magnetic particles in the core in the base material is different from the mass percentage of the micro-nano magnetic particles in the shell in the base material.

2. A preparation method of micro-nano magnetic composite particles is characterized by comprising the following steps:

the fluidization treatment is heating treatment;

the micro-nano magnetic composite particles are of spherical structures, wherein cross sections obtained by transversely cutting the micro-nano magnetic composite particles along the diameter of the composite particles through the spherical centers of the micro-nano magnetic composite particles, the cross sections are divided into different parts by two radiuses of the cross sections and arcs of the cross sections, and the mass percentage content of the micro-nano magnetic particles in the different parts is different.

3. A preparation method of micro-nano magnetic composite particles is characterized by comprising the following steps:

the fluidization treatment is heating treatment;

the micro-nano magnetic composite particles are of a double-spherical structure, and the weight percentages of the micro-nano magnetic particles in the double-spherical structure are different.

4. The preparation method according to any one of claims 1 to 3, wherein the heating treatment is to heat the micro-nano magnetic fiber integrally.

5. The preparation method according to any one of claims 1 to 3, wherein the heating treatment is local heating of the micro-nano magnetic fiber.

6. The production method according to any one of claims 1 to 3, wherein the heat treatment temperature is 60 ℃ to 500 ℃ and the heat treatment time is 1s to 24 h.

7. The preparation method according to any one of claims 1 to 3, wherein the micro-nano magnetic fiber is wound on a glass tube, fixed at two ends and placed in a muffle furnace for heating treatment.

8. The method according to any one of claims 1 to 3, wherein the chemical solvent is selected from at least one of: acetone, butanone, N-methylpyrrolidone, Dimethylacetamide (DMAC), Dimethylformamide (DMF), chloroform, cyclohexane, toluene, ethylbenzene, cumene, xylene, bromobenzene, chlorobenzene, dichloromethane, dichloroethane, tetrachloroethane, tetrachloroethylene, styrene, limonene, ethyl acetate, butyl acetate, hydrofluoric acid, alkali metal hydroxides.

9. The preparation method according to any one of claims 1 to 3, further comprising, after the fluidizing treatment, performing extrusion treatment on the fluidized micro-nano magnetic fiber while maintaining the glass transition temperature of the substrate, and permanently deforming the substrate under the extrusion action.

10. The preparation method according to claim 9, further comprising after the extrusion treatment, directionally dissolving the fiber cladding of the extruded micro-nano magnetic fiber by using a chemical solvent to obtain micro-nano magnetic composite particles.

11. The production method according to any one of claims 1 to 3, wherein the metal magnetic particles are selected from one or two or more of: ferromagnetic particles, cobalt magnetic particles, nickel magnetic particles.

12. The production method according to any one of claims 1 to 3, wherein the metal compound magnetic particles are metal oxide magnetic particles.

13. The production method according to any one of claims 1 to 3, wherein the metal compound magnetic particles are selected from one or two of: fe₃O₄Magnetic particles, gamma-Fe₂O₃Magnetic particles.

14. The production method according to any one of claims 1 to 3, wherein the metal alloy magnetic particles are selected from one or two or more of: neodymium iron boron alloy magnetic particles, samarium cobalt alloy magnetic particles, nickel cobalt alloy magnetic particles, and iron cobalt alloy magnetic particles.

15. The method of any one of claims 1-3, wherein the polymer is a thermoplastic polymer.

16. The production method according to any one of claims 1 to 3, wherein the polymer is selected from one or two or more of: polymethyl methacrylate (PMMA), PMMA composite material doped with fluorinated polymer (F-PMMA), styrene methyl dimethacrylate copolymer (SMMA), Cyclic Olefin Copolymer (COC), Cyclic Olefin Polymer (COP), Polycarbonate (PC), polyphenylene sulfone resin (PPSU), polyether sulfone resin (PES), Polyethyleneimine (PEI), Polystyrene (PS), Polyamide (PA) and polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), Polyacrylonitrile (PAN), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Polyurethane (PU), styrene-ethylene/butylene-styrene block copolymer (SEBS), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polytrimethylene terephthalate (PTT), and polyether.

17. The production method according to any one of claims 1 to 3, wherein the glass is selected from one or two or more of: chalcogenide glasses, germanate glasses, tellurate glasses, metal oxide glasses, silicate glasses, germanosilicate glasses, and fluoride glasses.

18. The method according to any one of claims 1 to 3, wherein the number of particles produced in a single pass is 2 to 1000000000 per cm of size.

19. A micro-nano magnetic composite particle prepared by the preparation method of any one of claim 1 and 4-18 referring to claim 1.

20. A micro-nano magnetic composite particle prepared by the preparation method of any one of claim 2 and 4-18 referring to claim 2.

21. A micro-nano magnetic composite particle prepared by the preparation method of any one of claim 3 and 4-18 referring to claim 3.

22. The micro-nano magnetic composite particles according to any one of claims 19 to 21, wherein the micro-nano magnetic particles are uniformly dispersed in the base material.

23. The micro-nano magnetic composite particle according to claim 22, wherein the micro-nano magnetic particles are present in an amount ranging from 0.01wt.% to 75wt.%, based on the total weight of the micro-nano magnetic composite particle.

24. The micro-nano magnetic composite particle according to claim 22, wherein the micro-nano magnetic particles are present in an amount ranging from 1wt.% to 75wt.%, based on the total weight of the micro-nano magnetic composite particle.

25. The micro-nano magnetic composite particle according to claim 19, wherein the micro-nano magnetic composite particle has a mass percentage of the micro-magnetic particles in the corresponding base material gradually decreasing along the core-shell direction.

26. The micro-nano magnetic composite particle according to claim 19, wherein the micro-nano magnetic composite particle comprises n shell structures, and n is an integer greater than or equal to 1.

27. The micro-nano magnetic composite particle according to claim 26, wherein the micro-nano magnetic particles in at least two shell structures are different in mass percentage in the core-shell structure.

28. The micro-nano magnetic composite particle according to claim 26, wherein the micro-nano magnetic particles gradually decrease in mass percentage from inside to outside in the shell structure.

29. The micro-nano magnetic composite particle according to claim 20, wherein the two radii of the cross section and the arc thereof divide the cross section into two equal parts, and the two parts have different mass percentages of micro-nano magnetic particles.

30. The micro-nano magnetic composite particle according to any one of claims 19 to 21, further comprising a metal wire, wherein the metal wire penetrates through the micro-nano magnetic composite particle.

31. The micro-nano magnetic composite particles according to any one of claims 19 to 21, wherein the size error range of the magnetic composite particles is ± (0.1-10%) of the size of the main particles.