TWI757680B - A kind of composite microsphere with radial fibrous mesoporous shell layer/hollow core layer structure and preparation method thereof - Google Patents

Abstract

The invention relates to a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure and a preparation method thereof. The composite microsphere has a cavity, a core layer and a mesoporous shell layer, and the mesoporous shell layer has radial fibers mesoporous pores. The composite microspheres have high sphericity and surface regularity, uniform particle size distribution, good monodispersity and high strength. The preparation method of the composite microsphere is simple and easy to implement and easy to industrialize, and the preparation of the radial fibrous mesoporous shell layer and the removal of the organic template can be completed in one step. The composite microspheres have the characteristics of high light scattering efficiency, large specific surface area, low density and high porosity, and can be widely used in light diffusing materials, as a high haze light diffusing agent, as a filler for coatings, and as a In the fields of cosmetics, catalysts, and water treatment.

Description

A kind of composite microsphere with radial fibrous mesoporous shell layer/hollow core layer structure and preparation method thereof

The invention belongs to the field of organic macromolecular compounds, in particular to a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure and a preparation method thereof.

Mesoporous silicon materials have attracted extensive attention due to their large specific surface area, uniform and continuously tunable pore size in nanometer size, and functionalization of surface groups. Hollow microspheres with particle sizes ranging from nanometers to micrometers have the advantages of large specific surface area, low density, high stability and surface permeability. The mesoporous silicon material with hollow structure integrates the characteristics of mesoporous structure and hollow structure, effectively utilizes the advantages of both and can derive new synergistic properties, so it has a wide range of scientific research and application prospects.

At present, such as Chinese invention patent CN2012104725129, which describes a preparation method of a hollow silica core/mesoporous silica shell monodisperse sphere, wherein the main component of the hollow mesoporous silica material is silica, specifically Using polystyrene microspheres as templates, adding inorganic silicon sources in two steps and removing the polystyrene templates through calcination, monodisperse spheres with double-layer shell layers of both silica are obtained. However, the hollow microspheres composed of pure silica are easy to agglomerate and are not easy to disperse in the substrate, and the monodisperse spheres prepared by the invention patent are not ideal in terms of light transmittance, haze and diffusivity.

In addition, the current preparation of hollow microspheres is generally to prepare core-shell composite microspheres first, and then remove the core particles through solvent dissolution or high temperature treatment. These methods are complicated in steps, harsh in synthesis conditions, generate a large amount of harmful gases during calcination to remove organic templates (such as polystyrene (PS) spheres, etc.), and the obtained hollow microspheres have serious agglomeration, which greatly limits the Application of hollow microspheres with mesoporous shells.

Therefore, in view of the shortcomings of the above-mentioned hollow microspheres and the defects of the preparation process, those skilled in the art are eager to seek a method to solve the above-mentioned problems.

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art. Therefore, the present invention provides a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure, which has good spherical, It has the advantages of narrow distribution, diverse performance and adjustable performance. When the composite microspheres are miscible with the substrate, their performance loss is kept to a minimum.

The present invention also provides a method for preparing the above-mentioned composite microspheres with a radial fibrous mesoporous shell layer/hollow core layer structure.

In order to solve the above problems, the inventors of the present invention have conducted intensive research and found that composite organosilicon microspheres having both a radial fibrous mesoporous shell layer and a hollow structure solve the above problems, thus completing the present invention.

In a first aspect of the present invention, the present invention provides a composite microsphere having a radial fibrous mesoporous shell layer/hollow core layer structure, the composite microspheres each comprising a cavity, a hollow core layer and radial fibrous mesopores shell. The composite microspheres have an average particle size in the range of 65 nanometers to 10 micrometers.

The diameter of the cavity of the composite microsphere is preferably 40 nanometers to 10 micrometers, the thickness of the hollow core layer is preferably 5 nanometers to 2 micrometers, and the thickness of the radial fibrous mesoporous shell layer is preferably 20 nanometers to 200 nanometers. nanometers.

Wherein, the material constituting the radial fibrous mesoporous shell is selected from the compound represented by the general formula R ₁ Si(OR ₄ ) ₃ , the compound represented by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ , and the general formula R 1 Si(OR 4 ) 2. A combination of one or more of the compounds represented by the formula Si(OR ₄ ) ₄ , the material composing the hollow core layer is the compound represented by the general formula Si(OR ₄ ) ₄ ; wherein, R ₄ is C _1-6 alkane group; R ₁ , R ₂ , R ₃ are each independently selected from hydrogen, substituted or unsubstituted C _1-6 alkyl, substituted or unsubstituted C _2-6 alkenyl, substituted or unsubstituted C _2-6 alkynyl group, substituted or unsubstituted C _6-12 aryl group, wherein substituted refers to amino group substituted by amino group, C _1-6 amino alkyl group, C _1-6 amino group Substituted with one or more substituents in alkoxy, oxygen-substituted C _1-6 alkoxy, or C _1-6 hydrocarbyl alkoxy.

Preferably, the material constituting the radial fibrous mesoporous shell layer contains at least a compound represented by the general formula R ₁ Si(OR ₄ ) ₃ and/or a compound represented by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ compound.

In a second aspect of the present invention, there is provided a method for preparing the above-mentioned composite microspheres with a radial fibrous mesoporous shell layer/hollow core layer structure, comprising the following steps: 1) preparing polystyrene microspheres; 2) preparing the The polystyrene microspheres, the first emulsifier, the water and the alcohol dispersant are mixed and uniformly dispersed, an alkaline regulator is added to adjust the solution to be alkaline, and the first material is added to carry out the first polymerization reaction to obtain a first reaction mixture, which is The first reaction mixture contains polystyrene microspheres coated with a silicon layer on the surface; 3) the temperature of the first reaction mixture is increased, the second emulsifier and the organic solvent are added, mixed uniformly, and then the second material is added to carry out the first step; Dipolymerization reaction to obtain the second reaction mixture containing the composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure; 4) Centrifuge, wash and dry the second reaction mixture to obtain radial fibers composite microspheres with a mesoporous shell layer/hollow core layer structure; the first material is a compound represented by the general formula Si(OR ₄ ) ₄ , and the second material is selected from the general formula R ₁ Si(OR ₄ ) ₃ A combination of one or more of the compound shown, the compound shown by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ , and the compound shown by the general formula Si(OR ₄ ) ₄ ; wherein, R ₄ is C _{1 -6} alkyl; R ₁ , R ₂ , R ₃ are each independently selected from hydrogen, substituted or unsubstituted C _1-6 alkyl, substituted or unsubstituted C _2-6 alkenyl, substituted or Unsubstituted C _2-6 alkynyl, substituted or unsubstituted C _6-12 aryl, wherein substituted means amino group substituted with C _1-6 aminoalkyl, C Substituted with one or more substituents in _1-6 alkoxy, oxygen-substituted C _1-6 alkoxy, or C _1-6 hydrocarbyl alkoxy.

According to some preferred aspects of the present invention, the composite microsphere has a cavity, a hollow core layer and a radial fibrous mesoporous shell layer, the diameter of the cavity is preferably 40 nanometers to 10 micrometers, and the diameter of the hollow core layer is preferably 40 nanometers to 10 micrometers. The thickness is preferably 5 nanometers to 2 micrometers, the thickness of the radial fibrous mesoporous shell layer is preferably 20 nanometers to 200 nanometers, and the average particle size of the composite microspheres is preferably 65 nanometers to 10 micrometers.

According to some preferred aspects of the present invention, the material constituting the radial fibrous mesoporous shell layer contains at least a compound represented by the general formula R ₁ Si(OR ₄ ) ₃ and/or the general formula R ₂ R ₃ Si(OR ) ₄ ) The compound shown in ₂ .

According to some preferred aspects of the present invention, in step 2), the mass ratio of the polystyrene microspheres, the first material, the first emulsifier and the water is 1:0.5~2:0.5~ 2: 20~50.

According to some preferred aspects of the present invention, in step 2), the volume ratio of the water, the alcohol-based dispersant and the alkaline regulator is 1:0.2~1:0.025~0.2.

According to some preferred aspects of the present invention, the feeding mass ratio of the polystyrene microspheres in step 2), the second material in step 3) and the second emulsifier in step 3) is 1: 0.5~5: 0.5~2. Under the dosage that satisfies the above conditions, complete hollow microspheres can be provided without the phenomenon of residual polystyrene microspheres, and the prepared composite microsphere shell layer of radial fibrous mesoporous shell layer/hollow core layer structure can meet the needs.

According to some preferred aspects of the present invention, the feed volume ratio of the water in step 2) to the organic solvent in step 3) is 1:0.1~10. More preferably, the feed volume ratio of the water in step 2) to the organic solvent in step 3) is 1:1~2.

According to some specific and preferred aspects of the present invention, in step 3), the organic solvent is selected from hydrocarbon solvents, benzene solvents, alcohol solvents or ketone solvents, wherein the hydrocarbon solvent is selected from cyclic solvents The combination of one or more in hexane, n-hexane, gasoline and pentane, the benzene-based solvent is a combination of one or more selected from benzene, toluene and xylene, the alcohol-based solvent is selected from methanol, ethanol and A combination of one or more of propanol; the ketone solvent is acetone and/or butanone.

According to some specific and preferred aspects of the present invention, in step 2), the alkaline modifier is a combination of one or more selected from an aqueous alkali metal hydroxide solution, urea, aqueous ammonia and triethanolamine.

According to some preferred aspects of the present invention, in step 2), the first emulsifier is preferably a cationic emulsifier.

According to some preferred aspects of the present invention, in step 3), the second emulsifier is preferably a cationic emulsifier.

According to some specific and preferred aspects of the present invention, the first emulsifier and the second emulsifier may be the same or different.

According to some specific and preferred aspects of the present invention, the cationic emulsifier is selected from cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, and cetyltrimethylammonium A combination of one or more of ammonium p-toluenesulfonate.

According to some preferred aspects of the present invention, in step 2), the first emulsifier is selected from cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, and hexadecane A combination of one or more cationic emulsifiers in ammonium trimethyl p-toluenesulfonate; in step 3), the second emulsifier is selected from cetyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride A combination of methylammonium bromide, and one or more cationic emulsifiers in ammonium cetyltrimethyl-p-toluenesulfonate.

According to some preferred aspects of the present invention, in step 2), the temperature of the first polymerization reaction is 25 to 70°C, and the reaction time is 4 to 24 hours.

According to some preferred aspects of the present invention, in step 3), the temperature of the second polymerization reaction is 35 to 80°C, and the reaction time is 0.5 to 8 hours.

Compared with the prior art, the main advantageous effects of the present invention are: 1. To provide a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure, which has the advantages of good spherical shape, narrow particle size distribution, various properties and adjustable properties. Compared with the existing microspheres, the performances of the microspheres of the present invention are obviously improved. For example, it can be applied to light diffusing plates, which can meet the requirements of high light transmittance, high haze and good diffusivity of light diffusing agents, such as thinning of lighting devices, reduction of absorbance and thinning of diffusion layers; for example, in cosmetics. , can be used as a functional powder with high oil absorption, soft focus and other effects; for example, it can be used as a lightweight filler in plastic, resin and other substrates to prepare lightweight composite materials; for example, it can also be used in thermal insulation materials, catalytic products, porous carriers, sustained-release drug carriers, etc. 2. To provide a preparation method of composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure. The preparation of the composite microspheres is based on a polystyrene microsphere modified with siloxane as a template, and in a specific silicon source precursor system, the formation of the radial fibrous mesoporous shell layer and the polymerization are completed in one step. Removal of styrene microspheres. The synthesis process of the invention is simple and feasible, easy for industrial production, and has broad application prospects.

Through long-term and in-depth research, the present inventor proposes a one-step synthesis of hollow microspheres with radial fibrous mesoporous shells in a specific silicon source precursor system using siloxane-modified polystyrene microspheres as templates. ball method. The composite microsphere prepared by the method has the structure of radial fibrous mesoporous shell layer and hollow core layer. The obtained product has a variety of excellent properties, and thus has a good application prospect in light diffusing plates, cosmetics and the like. On this basis, the inventors have completed the present invention. the term

As used herein, the term "C _1-6 hydrocarbyl" refers to an alkyl, alkenyl, or alkynyl group, and the like, having 1 to 6 carbon atoms. For example, C _1-6 alkyl, C _2-6 alkenyl, C _2-6 alkynyl and the like.

As used herein, the term "C _1-6 alkyl" refers to a straight or branched chain alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl group, tertiary butyl, tertiary butyl, or similar groups.

As used herein, the term "C _2-6 alkenyl" refers to a straight or branched chain alkenyl group having 2 to 6 carbon atoms, such as vinyl, allyl, 1-propenyl, isopropenyl, 1- Butenyl, 2-butenyl, or similar groups.

As used herein, the term " _C2-6alkynyl " refers to a straight or branched chain alkynyl group having 2 to 6 carbon atoms, such as ethynyl, propynyl, and the like.

As used herein, the term " _C6-12 aryl" refers to a monocyclic or bicyclic aromatic hydrocarbon group, such as phenyl, naphthyl, or the like.

As used herein, the term "C _1-6 alkoxy" refers to a straight or branched chain alkoxy group having 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy , butoxy, isobutoxy, secondary butoxy, tertiary butoxy, or similar groups.

As used herein, the term "oxy-substituted C _1-6 alkoxy" may refer to the substitution of oxygen (=O) at any position of the C _1-6 alkoxy group or substitution of two positions by oxygen to form a ring oxygen.

As used herein, the term "C _1-6 aminoalkyl" refers to a C _1-6 alkyl group substituted with an amino group, that is, any position of the alkyl group is substituted with an amino group.

As used herein, the term "C _1-6 hydrocarbyl alkanoyloxy" refers to a Ci- ₆ hydrocarbyl substituted alkanoyloxy group (C _1-6 hydrocarbyl-(C=O)O-).

As used herein, the term "has a radially fibrous mesoporous shell/hollow core structure" refers to a structure having a radially fibrous mesoporous shell and a hollow core. The siloxane monomers mentioned in the first material and the second material respectively

In the preparation of composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure according to the present invention, the first material is a compound represented by the general formula Si(OR ₄ ) ₄ , the second material is is selected from the compound represented by the general formula R ₁ Si(OR ₄ ) ₃ , the compound represented by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ , and the compound represented by the general formula Si(OR ₄ ) ₄ . One or more combinations; wherein, R ₄ is C _1-6 alkyl; R ₁ , R ₂ , R ₃ are each independently selected from hydrogen, substituted or unsubstituted C _1-6 alkyl, substituted or unsubstituted Substituted C _2-6 alkenyl, substituted or unsubstituted C _2-6 alkynyl, substituted or unsubstituted C _6-12 aryl; wherein, substituted means selected from amino, One or more substituents in C _1-6 aminoalkyl substituted amino, C _1-6 alkoxy, oxygen substituted C _1-6 alkoxy, or C _1-6 hydrocarbyl alkoxy replaced. Composite microspheres with radial fibrous mesoporous shell/hollow core structure

The invention provides a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure. The composite microsphere has a cavity, a hollow core layer and a radial fibrous mesoporous shell layer. The average particle diameter of the composite microspheres can be freely designed according to their applications, and thus is not particularly limited. The average particle size is usually in the range of 65 nanometers to 10 micrometers. cavity

The diameter of the cavity of the composite microsphere is preferably 40 nanometers to 10 micrometers; more preferably 500 nanometers to 1.5 micrometers.

The uniform and monodispersed microspheres are used as cavity template microspheres, and the diameter-adjustable composite microspheres are obtained by adjusting the particle size of the microspheres. The template microspheres used to generate the cavity are preferably polystyrene microspheres. hollow core layer

The thickness of the hollow core layer of the composite microsphere is preferably 5 nanometers to 2 micrometers; more preferably 10 to 500 nanometers.

The hollow core layer of the composite microsphere is preferably obtained by polymerizing siloxane monomers, and the siloxane monomer system constituting the hollow core layer is selected from the general formula Si(OR ₄ ) ₄ ; wherein, R ₄ is C _1-6 alkyl; the preferred examples thereof are tetraethoxysilane and tetramethoxysilane. The hollow core layer of the present invention needs to have certain solvent resistance, emulsifier adsorption of the outer layer, and stability of the through-hole structure, so that the hollow structure of the composite microsphere can withstand the swelling of organic solvents, and can effectively move through the through-holes. The templated microspheres can be removed without destroying the hollow structure, and can accept the adsorption of emulsifier to effectively form a mesoporous shell layer. radial fibrous mesoporous shell

The thickness of the mesoporous shell layer of the composite microsphere is preferably 20 to 200 nanometers; more preferably, 150 to 200 nanometers.

The radial fibrous mesoporous shell layer of the composite microsphere is preferably obtained by polymerizing a siloxane monomer, wherein the siloxane monomer constituting the radial fibrous mesoporous shell layer is selected from the general formula R ₁ Si ( OR ₄ ) ₃ , the compound represented by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ , and the compound represented by the general formula Si(OR ₄ ) _4. One or more combinations; wherein, R ₄ is C _1-6 alkyl; R ₁ , R ₂ , R ₃ are each independently selected from hydrogen, substituted or unsubstituted C _1-6 alkyl, substituted or unsubstituted C _2-6 alkenyl , substituted or unsubstituted C _2-6 alkynyl, substituted or unsubstituted C _6-12 aryl, wherein substituted refers to a substituted or unsubstituted C _1-6 amine alkyl group selected from amino groups Substituted with one or more substituents of amino, C _1-6 alkoxy, oxygen-substituted C _1-6 alkoxy, or C _1-6 hydrocarbyl alkoxy.

Preferably, the siloxane monomer system constituting the radial fibrous mesoporous shell layer contains at least a compound represented by the general formula R ₁ Si(OR ₄ ) ₃ and/or the general formula R ₂ R ₃ Si(OR ₄ ) The compound shown in ₂ , its examples are preferably C ₆ H ₅ Si(OCH ₃ ) ₃ (phenyltrimethoxysilane), CH ₃ Si(OCH ₃ ) ₃ (methyltrimethoxysilane), methylbenzene dimethoxysilane, diphenyldimethoxysilane, methacryloyloxypropyltrimethoxysilane, glycidyloxypropyltrimethoxysilane, N-(β-aminoethyl)- γ-Aminopropyltrimethoxysilane, Methylphenyldiethoxysilane, Vinyltriethoxysilane, Vinyltrimethoxysilane, Dimethyldimethoxysilane, γ-(2,3 -glycidoxy)propyltrimethoxysilane, gamma-(methacryloyloxy)propyltrimethoxysilane, aminopropyltrimethoxysilane, methyltriethoxysilane (MTEOS), or its combination.

More preferably, the siloxane monomer system constituting the radial fibrous mesoporous shell layer contains at least a compound represented by the general formula R ₁ Si(OR ₄ ) ₃ and/or the general formula R ₂ R ₃ Si(OR ₄ ) The compound represented by ₂ , which more selectively contains the compound represented by the general formula Si(OR ₄ ) ₄ , the example of which is preferably tetraethoxysilane (TEOS) and a compound selected from C ₆ H ₅ Si(OCH ₃ ) ₃ (Phenyltrimethoxysilane), CH ₃ Si(OCH ₃ ) ₃ (Methyltrimethoxysilane), Methylphenyldimethoxysilane, Diphenyldimethoxysilane, Methacrylamide Oxypropyltrimethoxysilane, Glycidoxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, Methylphenyldiethoxysilane, Vinyltriethoxysilane, vinyltrimethoxysilane, dimethyldimethoxysilane, γ-(2,3-glycidoxy)propyltrimethoxysilane, γ-(methacryloyl) A combination of at least one of propyltrimethoxysilane, aminopropyltrimethoxysilane, methyltriethoxysilane (MTEOS).

More preferably, the siloxane monomer constituting the radial fibrous mesoporous shell layer is a combination selected from the following: TEOS and glycidyloxypropyltrimethoxysilane, TEOS and phenyltrimethoxysilane, TEOS with aminopropyltrimethoxysilane, or TEOS with diphenyldimethoxysilane.

The siloxane monomer constituting the radial fibrous mesoporous shell layer is more preferably phenyltrimethoxysilane and selected from CH ₃ Si(OCH ₃ ) ₃ (methyltrimethoxysilane), methyl phenyl dimethyl silane Oxysilane, Diphenyldimethoxysilane, Methacryloyloxypropyltrimethoxysilane, Glycidoxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-amine Propyltrimethoxysilane, Methylphenyldiethoxysilane, Vinyltriethoxysilane, Vinyltrimethoxysilane, Dimethyldimethoxysilane, γ-(2,3-Epoxy Propoxy)propyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, aminopropyltrimethoxysilane, tetraethoxysilane (TEOS), methyltriethoxysilane A combination of at least one of (MTEOS).

More preferably, the siloxane monomer constituting the radial fibrous mesoporous shell layer is selected from the following combinations: phenyltrimethoxysilane and MTEOS, phenyltrimethoxysilane and vinyltriethoxysilane, Phenyltrimethoxysilane with dimethyldimethoxysilane, Phenyltrimethoxysilane with γ-(2,3-glycidoxy)propyltrimethoxysilane, Phenyltrimethoxysilane with γ -(Methacryloyloxy)propyltrimethoxysilane, phenyltrimethoxysilane and aminopropyltrimethoxysilane, or phenyltrimethoxysilane and MTEOS and phenylmethyldimethoxysilane. Preparation method of composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure

The composite microspheres with the radial fibrous mesoporous shell layer/hollow core layer structure of the present invention are preferably prepared according to the following method: 1) Preparation of polystyrene microspheres as core templates; 2) Then, a first-stage polymerization reaction is performed to form a shell layer surrounding the polystyrene microspheres obtained in step 1). At a certain temperature (such as 25~70℃), in a certain proportion, the polystyrene microspheres prepared in step 1), the first emulsifier, water, and alcohol dispersant are mixed and uniformly dispersed, and alkaline is added to adjust After adjusting the solution to alkaline with the agent, adding the first material (i.e. siloxane monomer, such as a siloxane monomer or a mixture of multiple siloxane monomers) for a period of time (such as 4 to 24 hours) for polymerization, A first reaction mixture containing polystyrene microspheres coated with a silicon layer was obtained. Therefore, the hollow core layer of the composite microsphere is obtained by polymerizing the siloxane monomer in step 2). 3) Next, the second-stage polymerization reaction and the simultaneous removal of the core template are performed to obtain a second reaction mixture containing the composite microspheres having the radial fibrous mesoporous shell layer/hollow core layer structure. At a certain temperature (such as 35~80℃), add the second emulsifier and organic solvent to the first reaction mixture obtained in step 2) and mix them evenly, and finally add the second material (ie, siloxane monomer, such as A siloxane monomer or a mixture containing two siloxane monomers) is subjected to the second polymerization reaction, while the template (polystyrene microspheres) is dissolved, and after a period of time (such as 0.5 to 8 hours), a mixture containing The second reaction mixture of composite microspheres of radial fibrous mesoporous shell/hollow core structure. 4) The second reaction mixture is centrifuged, washed and dried to obtain composite microspheres with a radial fibrous mesoporous shell layer/hollow core layer structure.

Therefore, the radial fibrous shell layer of the composite microsphere is obtained by polymerizing the siloxane monomer in step 3), and the above-mentioned polymerization reaction is preferably carried out under the condition of heating, which is conducive to the formation of the shell layer.

In the composite microspheres with the radial fibrous mesoporous shell layer/hollow core layer structure, the weight ratio of the hollow core layer to the radial fibrous mesoporous shell layer is approximately equal to the silicon oxide added in step 2) and step 3). The weight ratio of alkane monomers.

Among them, by adjusting the types and weight ratios of siloxane monomers in step 2) and adjusting the types and weight ratios of siloxane monomers in step 3), the hollow core layers and radial fibrous mesopores in the composite microspheres are formed. The shell layer suffices.

In step 2) or step 3), the siloxane monomer can be selected from one or more of the siloxane monomers described above in the present invention.

The implementation of the above-mentioned preparation method of the present invention can break through the limitation of the state of the radial fibrous mesoporous shell layer of the hollow composite microspheres prepared by the current calcination method. application

Compared with the microspheres with traditional mesopores, the composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure of the present invention, the microspheres with radial fibrous mesopores in the shell layer have the characteristics of high specific surface area. , and also has more hierarchical-sized pores, which make it have good permeability, large pore volume, and improve the loading capacity of guest molecules. Optically, the multi-layered size of the channels allows more substrates to penetrate into the voids, forming a transition layer with a graded refractive index function and favorable light diffusion. Mechanically, the multi-layered pore size is beneficial to the tighter bonding between the substrate and the microspheres and better mechanical strength.

The composite microsphere with the radial fibrous mesoporous shell layer/hollow core layer structure of the present invention has the advantages of good spherical shape, narrow particle size distribution, various properties and adjustable properties. Compared with the existing microspheres, the performances of the microspheres of the present invention are obviously improved. Therefore, it has a wide range of application prospects. For example, it can be used in light diffusing plates, which can deal with the thinning of lighting devices, the reduction of absorbance and the thinning of diffusion layers. The light diffusing agent has high transmittance, high haze and good diffusivity. For example, when used in cosmetics, it can be used as a functional powder with high oil absorption, soft focus, etc.; Example

The present invention will be specifically described by the following examples and comparative examples, but the present invention is not limited to the scope of these examples. In the following examples, if the experimental method of specific conditions is not indicated, it is usually in accordance with the conventional conditions, or in accordance with the conditions suggested by the manufacturer. All raw materials, unless otherwise specified, are usually obtained from commercial sources or prepared by conventional methods in the art. Example 1

Add 6 g of styrene monomer to a three-necked flask containing 100 ml of deionized water, stir mechanically (rotation speed 250 rpm) at room temperature, and pass nitrogen for 30 minutes. When the temperature was raised to 70°C under a nitrogen atmosphere, 60 mg of an initiator KPS (potassium persulfate) was added, and the reaction was carried out for 24 hours. The product was transferred to a centrifuge tube, centrifuged, washed with ethanol, centrifuged, and dried in a blast oven at 50°C for use. The morphology of the product is shown in Figure 1, with an average particle size of 967 nm and a polydispersity index (PDI) of 1.11.

Weigh 0.4 g of cetyltrimethylammonium bromide (CTAB) into a 100-ml round-bottom flask, and then add 20 ml of water and 8 ml of absolute ethanol to the flask. 450 mg of the prepared polystyrene microspheres were weighed and added to the flask, then 1 ml of ammonia water was added, and the mixture was stirred at room temperature for 30 minutes. 500 microliters of TEOS was added dropwise to the system, and the reaction was carried out at room temperature for 24 hours under stirring conditions.

Subsequently, the reaction temperature was raised to 50°C, 300 mg of cetyltrimethylammonium bromide (CTAB) and 20 ml of cyclohexane were added to the system, and after magnetic stirring for 10 minutes, 3.5 g of TEOS and 0.3 g of Methacryloyloxypropyltrimethoxysilane. The reaction was carried out under magnetic stirring at 800 rpm for 1 hour.

After cooling to room temperature naturally, the reaction solution was centrifuged with a HC-2518 ZONKIA centrifuge (5000 rpm) to separate the solid product, washed three times with industrial ethanol ultrasonically, and placed in an electric heating blast drying oven at 50 °C. Dry in medium. The TEM photo of the product morphology is shown in Figure 2. It is a composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure. The cavity size is similar to that of the polystyrene template microsphere. The radial fibrous mesoporous shell layer The thickness is about 40 nm. The nitrogen adsorption-desorption curve test of the product and the corresponding BJH pore size distribution (the sample was degassed under a vacuum condition of 60 °C for 2 hours before the test) are shown in Figure 3a and Figure 3b, and its adsorption and desorption isotherm curve is It is an IV-type curve, and there is an H3-type hysteresis loop, indicating that the microsphere wall has a mesoporous structure. The BET specific surface area of the composite microspheres is calculated from Fig. 3 to be 704.4 m2/g, and the corresponding BJH pore size distribution map shows that the mesopore size distribution is mainly concentrated around 10 nm.

Example 2

Composite microspheres having a radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the first polymerization time for preparing the hollow core layer was 12 hours, and the prepared The TEM photo of the composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure is shown in Figure 6, Figure 7 is an enlarged view of the composite microspheres in Figure 6, and the corresponding average particle size of the composite microspheres is 1 microns.

Example 3

Composite microspheres having a radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the organic solvent was replaced by n-hexane.

Example 4

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the second polymerization reaction for preparing the fibrous mesoporous shell layer was carried out at room temperature proceed below.

Example 5

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 20 nm by replacing gram TEOS with 0.3 gram glycidoxypropyl trimethoxysilane.

Example 6

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 Instead of gram TEOS and 0.5 gram phenyltrimethoxysilane, the thickness of the fibrous mesoporous shell is about 50 nm. Example 7

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 Instead of gram TEOS and 0.3 gram aminopropyltrimethoxysilane, the thickness of the fibrous mesoporous shell is about 55 to 60 nm. Example 8

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 42 nm by replacing gram TEOS with 0.3 gram diphenyldimethoxysilane. Example 9

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 40 nm by replacing gram of phenyltrimethoxysilane with 0.3 gram of MTEOS. Example 10

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 Instead of gram phenyltrimethoxysilane and 0.3 gram vinyltriethoxysilane, the thickness of the fibrous mesoporous shell is about 40 nm. Example 11

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 20 nm by replacing gram phenyltrimethoxysilane and 0.3 gram dimethyldimethoxysilane. Example 12

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 50 nm by replacing gram of phenyltrimethoxysilane with 0.3 grams of γ-(2,3-glycidoxy)propyltrimethoxysilane. Example 13

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 55 nm by replacing gram of phenyltrimethoxysilane with 0.3 grams of γ-(methacryloyloxy)propyltrimethoxysilane. Example 14

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 The thickness of the fibrous mesoporous shell is about 55 to 60 nm by replacing gram phenyltrimethoxysilane and 0.3 gram aminopropyltrimethoxysilane. Example 15

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the siloxane monomer system used to prepare the fibrous mesoporous shell layer was changed from 3.5 Instead of gram phenyltrimethoxysilane, 0.15 grams MTEOS and 0.15 grams phenylmethyldimethoxysilane, the thickness of the fibrous mesoporous shell is about 45 nm. Example 16

Composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure were prepared in the same manner as in Example 1, except that the average particle size of the polystyrene microspheres used to prepare the cavity template was 40 nanometer, the average particle size of the corresponding composite microspheres is 90 nanometers. Comparative Example 1 Ordinary hollow mesoporous SiO ₂

Ordinary hollow silica microspheres were prepared by the same method: take 0.4 g of cetyltrimethylammonium bromide (CTAB) into a 100-ml round-bottomed flask, then add 20 ml of water, 8 ml of anhydrous to the flask ethanol, and 450 mg of polystyrene microspheres were weighed and added to the flask, then 1 ml of ammonia water was added, and the mixture was stirred at room temperature for 30 minutes. 750 liters of TEOS was added dropwise to the system, and the reaction was carried out at room temperature for 24 hours under stirring conditions. After the reaction was completed, the reaction solution was transferred to a centrifuge tube, and centrifuged using a HC-2518 ZONKIA centrifuge at a rotational speed of 8000 rpm. The bottom precipitate was collected, washed three times with industrial ethanol ultrasonically, and dried in an electric heating blast drying oven at 50 °C. The morphology of the product is shown in Figure 4a, which is a solid polystyrene (PS) core layer/SiO ₂ Shell composite microspheres. The product was continued to be calcined at a high temperature of 550° C. for 4 hours in a muffle furnace to obtain ordinary hollow mesoporous silica microspheres as shown in FIG. 4 b , the shell of which was ordinary solid SiO ₂ .

The nitrogen adsorption-desorption curve test of ordinary hollow mesoporous silica microspheres and the corresponding BJH pore size distribution (the samples were degassed at 60 °C for 2 hours before the test) are shown in Figure 5a and Figure 5b. The adsorption-desorption isotherm curves of ordinary hollow mesoporous silica microspheres belong to the IV-type curve, and there is an H3-type hysteresis loop, indicating that the sphere wall has a mesoporous structure. The calculated BET specific surface area is 186.2 m2/g, which is much lower than the BET specific surface area of hollow fibrous mesoporous silica microspheres. The pore size distribution of the samples was calculated by the BJH method. The mesopore size distribution of ordinary hollow mesoporous silica microspheres was about 10 to 100 nanometers (the mesopores were 2 to 50 nanometers). The mesopore size distribution of silica microspheres is broad.

All documents mentioned herein are incorporated by reference in this application as if each document were individually incorporated by reference. In addition, it should be understood that after reading the above disclosure of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these changes or modifications also fall within the scope defined by the appended patent scope of the present application.

without

Fig. 1 is a SEM photograph of the PS microspheres of Example 1, wherein the inset in Fig. 1b is a TEM photograph corresponding to the SEM photograph of Fig. 1b.

FIG. 2 is a TEM photograph of the composite microsphere with a radial fibrous mesoporous shell layer/hollow core layer structure of Example 1 (FIG. 2a, FIG. 2b are different magnifications).

FIG. 3 is the nitrogen adsorption-desorption curve and BJH pore size distribution diagram of the composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure of Example 1, wherein FIG. Nitrogen adsorption-desorption curves of the composite microspheres with the mesoporous shell layer/hollow core layer structure, Figure 3b is the corresponding BJH pore size distribution.

FIG. 4 is a TEM photograph of the polystyrene (PS) core layer/SiO ₂ shell layer microspheres of Comparative Example 1, wherein FIG. 4a is a solid polystyrene (PS) core layer/SiO ₂ shell layer composite microsphere before calcination spheres, and Figure 4b shows the calcined ordinary hollow mesoporous silica microspheres.

FIG. 5 is the nitrogen adsorption-desorption curve and BJH pore size distribution diagram of the ordinary hollow mesoporous silica microspheres of Comparative Example 1, wherein, FIG. 5a is the nitrogen adsorption of the ordinary hollow mesoporous silica microspheres of Comparative Example 1 - Desorption curves, Figure 5b is the corresponding BJH pore size distribution.

FIG. 6 is a TEM photograph of the composite microsphere with the radial fibrous mesoporous shell layer/hollow core layer structure of Example 2 (a, b are different magnifications).

FIG. 7 is an enlarged TEM photograph of the composite microsphere with the radial fibrous mesoporous shell/hollow core structure in FIG. 6 .

Claims (4)

A preparation method of composite microspheres with radial fibrous mesoporous shell layer/hollow core layer structure, characterized in that, the preparation method comprises the following steps: 1) preparing polystyrene microspheres; 2) preparing the polystyrene microspheres The ball, the first emulsifier, water, and the alcohol dispersant are mixed and dispersed uniformly, the solution is adjusted to be alkaline by adding an alkaline regulator, and the first material is added to carry out the first polymerization reaction to obtain a first reaction mixture, the first reaction mixture Containing polystyrene microspheres coated with a silicon layer on the surface; 3) raising the temperature of the first reaction mixture, adding a second emulsifier and an organic solvent, mixing uniformly, and then adding a second material to carry out the second polymerization reaction, Obtain the second reaction mixture containing the composite microspheres with the radial fibrous mesoporous shell layer/hollow core layer structure; 4) Centrifuge, wash and dry the second reaction mixture to obtain the radial fibrous mesoporous shell A composite microsphere with a layer/hollow core layer structure; the first material is a compound represented by the general formula Si(OR ₄ ) ₄ , and the second material is a compound represented by the general formula R ₁ Si(OR ₄ ) ₃ , a compound represented by the general formula R ₂ R ₃ Si(OR ₄ ) ₂ , and a combination of one or more compounds represented by the general formula Si(OR ₄ ) ₄ ; wherein, R ₄ is a C _1-6 alkyl group ; R ₁ , R ₂ , R ₃ are each independently selected from hydrogen, substituted or unsubstituted C _1-6 alkyl, substituted or unsubstituted C _2-6 alkenyl, substituted or unsubstituted C _2-6 alkynyl, substituted or unsubstituted C _6-12 aryl, wherein substituted refers to a group selected from the group consisting of amino, C _1-6 amino substituted amino, C _1-6 alkane substituted by one or more substituents in oxy, C _1-6 alkoxy substituted by oxygen, or C _1-6 hydrocarbyl alkoxy; wherein, in step 2), the polystyrene microspheres, The mass ratio of the first material, the first emulsifier and the water is 1:0.5~2:0.5~2:20~50; wherein, in step 2), the water, the alcohol dispersant and The volume ratio of the alkaline regulator is 1:0.2~1:0.025~0.2; wherein, the polystyrene microspheres in step 2), the second material in step 3) and the first material in step 3) are The feed mass ratio of the two emulsifiers is 1:0.5~5:0.5~2; wherein, in step 2), the temperature of the first polymerization reaction is 25 to 70 ° C, and the reaction time is 4 to 24 hours; and wherein , in step 3), the temperature of the second polymerization reaction is 35 to 80° C., and the reaction time is 0.5 to 8 hours. The preparation method according to claim 1, wherein, in step 3), the organic solvent is selected from hydrocarbon solvents, benzene solvents, alcohol solvents or ketone solvents, wherein the hydrocarbon solvent is selected from cyclohexane The combination of one or more of alkane, n-hexane, gasoline and pentane, the benzene-based solvent is a combination of one or more selected from benzene, toluene and xylene, and the alcohol-based solvent is selected from methanol, ethanol and propylene A combination of one or more of alcohols, and the ketone solvent is acetone and/or butanone. The preparation method according to claim 1, wherein, in step 2), the alkaline regulator is a combination of one or more selected from the group consisting of an aqueous alkali metal hydroxide solution, urea, aqueous ammonia and triethanolamine; and/or , in step 2), the alcohol dispersant is ethanol. The preparation method according to claim 1, wherein, in step 2), the first emulsifier is selected from cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, and ten Hexaalkyltrimethyl A combination of one or more cationic emulsifiers in ammonium p-toluenesulfonate; in step 3), the second emulsifier is selected from cetyltrimethylammonium chloride, cetyltrimethyl bromide A combination of ammonium chloride and one or more cationic emulsifiers in ammonium cetyltrimethyl-p-toluenesulfonate.

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