CN108144558B - Hollow porous microsphere coated with titanium dioxide nanoparticles and preparation method thereof - Google Patents
Hollow porous microsphere coated with titanium dioxide nanoparticles and preparation method thereof Download PDFInfo
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Abstract
The invention relates to a hollow porous microsphere coated with titanium dioxide nano particles and a preparation method thereof, styrene, bifunctional dimethacrylate organic monomer and photoinitiator are dissolved in a solvent to obtain an electric spraying solution, modified titanium dioxide with double bonds on the surface is added into the electric spraying solution to be uniformly dispersed, electrostatic spraying is carried out under the condition of visible light to prepare the hollow porous microsphere coated with the titanium dioxide nano particles, the hollow porous microsphere coated with the titanium dioxide nano particles is composed of the titanium dioxide nano particles and cross-linking spheres coated on the surfaces of the titanium dioxide nano particles, the cross-linking spheres are hollow inside and porous on the surface and have a cross-linking structure formed by mutual cross-linking of copolymer molecular chains, and the titanium dioxide nano particles are connected with the cross-linking spheres through covalent bonds. The method has simple and convenient process and reasonable preparation flow, and the finally prepared hollow porous microspheres have good extinction effect, good medium-long wave ultraviolet shielding effect, high melting temperature and thermal decomposition temperature and extremely high popularization value.
Description
Technical Field
The invention belongs to the field of preparation of high-molecular nano materials, and particularly relates to a hollow porous microsphere coated with titanium dioxide nano particles and a preparation method thereof.
Background
In recent years, the hazards of ultraviolet radiation have been increasingly discovered. Excessive irradiation of ultraviolet rays may cause skin cancer. Ultraviolet rays not only degrade polymer chains in plastics, synthetic resins and rubbers to cause aging of materials, but also deteriorate the weather resistance of paint coatings, resulting in easy powdering, easy cracking, and even dropping of the paint coatings, and in addition, yellowing, embrittlement and the like of paper are associated with ultraviolet rays. Therefore, ultraviolet screening agents are increasingly added to polymer materials, and research on polymer materials compounded with ultraviolet absorbers is attracting more and more attention.
The high-voltage electrostatic spraying method is a method for preparing polymer particles from polymer solution or melt by using an electro-hydrodynamic technology. Compared with other methods for preparing the polymer particles, such as a precipitation method, a reversed-phase suspension crosslinking method, a spray drying method and the like, the electrostatic spraying method for preparing the microsphere material has the advantages of simple process, strong controllability, environmental protection and no need of using a large amount of emulsifying agents, the electrostatic spraying method is adopted to easily prepare the monodisperse particles, and the finally obtained particles can have various shapes, such as hollow and porous shapes and the like, for example, it has been reported in the literature (wariki. electrospinning method for preparing polystyrene functional material [ D ]. Jilin university, 2010.), that a polystyrene solution can be used to prepare porous hollow microspheres by electrostatic spray molding, and the prepared Polystyrene (PS) hollow microspheres have stable chemical properties at room temperature and good processability, however, since the glass transition temperature of Polystyrene (PS) is only 100 ℃, the three-dimensional structure is broken at a high temperature, and thus it cannot be applied to melt processing. This greatly affects the application of hollow microspheres of PS.
The titanium dioxide has outstanding tinting strength, covering power and extinction capability, is a white pigment with the best performance in the world at present, can be widely applied to the industrial fields of coatings, plastics, printing ink, paper making and the like, has larger demand, can effectively solve the defect of poor dispersibility in a high polymer matrix by inorganic coating of elements such as Al or Si and the like, and has excellent application prospect. However, the compatibility of titanium dioxide and polymer is poor, so that when the titanium dioxide is used as an additive to prepare the delustering fiber, the delustering effect of the delustering fiber is poor under the condition of small addition amount, and the delustering fiber has the defect that the delustering fiber is difficult to be thinner due to the addition of the titanium dioxide in the fiber. In addition, when the titanium dioxide is used for preparing the ultraviolet shielding material, because the absorption wavelength is determined by the band gap of the compound, the ultraviolet shielding material has poor shielding effect on long-wave ultraviolet (UV-A), namely ultraviolet with the wavelength of 320-400nm, and has limited protection capability on the long-wave ultraviolet.
Therefore, the research on the hollow porous microspheres coated with the titanium dioxide nanoparticles, which have the advantages of good extinction effect, good dispersion compatibility, good shielding effect on medium-long wave ultraviolet rays and high melting temperature and thermal decomposition temperature, has very important significance.
Disclosure of Invention
The invention aims to overcome the defects of poor extinction effect, poor dispersion phase compatibility, poor medium-long wave ultraviolet shielding effect and low melting and thermal decomposition temperatures in the prior art when titanium dioxide is used as an additive to prepare a high-molecular composite material, and provides hollow porous microspheres coated with titanium dioxide nano particles, which have the advantages of good extinction effect, good dispersion phase compatibility, good medium-long wave ultraviolet shielding effect and high melting and thermal decomposition temperatures.
In order to achieve the purpose, the invention adopts the technical scheme that:
a hollow porous microsphere coated with titanium dioxide nanoparticles mainly comprises titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles;
the cross-linked sphere is hollow inside, porous in surface and provided with a cross-linked structure, and the cross-linked structure is formed by cross-linking copolymer molecular chains containing styrene and bifunctional dimethacrylate monomer structural units;
the titanium dioxide nano particles are connected with the cross-linked spheres through covalent bonds.
As a preferred technical scheme:
the hollow porous microspheres coated with titanium dioxide nanoparticles have a melting temperature of more than 530 ℃ and a thermal decomposition temperature of more than 380 ℃. The processing temperature of the base material compounded with the titanium dioxide is generally less than 280 ℃, so that when the composite material is processed, the hollow porous microspheres coated with the titanium dioxide nano particles can keep a better three-dimensional structure and are beneficial to fully exerting the effect of the hollow porous microspheres.
The diameter of the cross-linked sphere is 500-1500 nm, and the wall thickness of the cross-linked sphere is 50-100 nm; the diameter of the titanium dioxide nano-particles is 300-400 nm; the number of the titanium dioxide nanoparticles in the crosslinking ball is 1-4.
When the number of the titanium dioxide nanoparticles in the cross-linked sphere is less than or equal to 2, the distribution density of the small holes on the surface of the cross-linked sphere is 1-60/1000nm2The aperture of the small hole is 10-30 nm;
the amount of titanium dioxide nanoparticles inside the crosslinked spheres>2, the distribution density of the pores on the surface of the cross-linked ball is 1-20 pores/1000 nm2The aperture of the small hole is 10-80 nm.
The invention also provides a method for preparing the hollow porous microsphere coated with the titanium dioxide nano particles, which is characterized in that styrene, bifunctional dimethacrylate organic monomer and photoinitiator are dissolved in a solvent to obtain an electrospray solution, modified titanium dioxide with double bonds on the surface is added into the electrospray solution to be uniformly dispersed, and electrostatic spraying is carried out under the condition of visible light to prepare the hollow porous microsphere coated with the titanium dioxide nano particles.
As a preferred technical scheme:
in the method, the step of uniformly dispersing refers to mechanically stirring at the rotating speed of 200-500 rpm for 1 hour; the preparation steps of the modified titanium dioxide are as follows:
(1) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid; the mass ratio of titanium dioxide, absolute ethyl alcohol and n-butyl titanate in the mixed dispersion liquid is 4-6: 150-250: 1;
(2) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4-5 h at the temperature of 60-70 ℃, and aging for 10-12 h at room temperature to obtain an aging liquid; the mass ratio of ethanol to water in the ethanol-water mixed solution is 2-5: 1, and the addition amount of the ethanol-water mixed solution is 20-30% of the volume of the mixed dispersion liquid;
(3) dripping a silane coupling agent into an ethanol water solution, stirring and hydrolyzing for 2-3 h at room temperature, adding into an aging solution subjected to ultrasonic dispersion for 30-60 min, and performing reflux reaction for 4-5 h at 60-70 ℃; the mass ratio of ethanol to water in the ethanol aqueous solution is 2-5: 1, the mass ratio of the silane coupling agent to the ethanol aqueous solution is 1: 8-12, the addition amount of the silane coupling agent is 5-10% of the mass of titanium dioxide in the aging liquid, and the silane coupling agent is gamma-methacryloxypropyl trimethoxysilane;
(4) and (3) performing rotary evaporation drying at 50-70 ℃, and then performing vacuum drying at 70-80 ℃ for 12-16 h to obtain the modified titanium dioxide with the surface containing double bonds.
In the method, the bifunctional dimethacrylate organic monomer is more than one of Bis-GMA, EBPADMA, UDMA, TEGDMA and D3 MA; the specific structural formula of the bifunctional dimethacrylate organic monomer is as follows:
the photoinitiator is DMPOH (N, N-dimethylamino phenethyl alcohol) and/or CQ (1,7, 7-trimethyl bicyclo (2,2,1) -2,3 heptanedione);
the wavelength of the visible light is 400-500 nm;
the solvent is more than one of DMF, trichloromethane, dichloromethane and tetrahydrofuran.
According to the method, in the electrospray solution, the bifunctional dimethacrylate organic monomer accounts for 5-25 wt% of the total amount of the styrene and the bifunctional dimethacrylate organic monomer, the solvent accounts for 50-80 wt% of the total amount of the styrene and the bifunctional dimethacrylate organic monomer, and the photoinitiator accounts for 0.5-1.2 wt% of the total amount of the styrene and the bifunctional dimethacrylate organic monomer; the adding amount of the modified titanium dioxide is 15-40% of the mass of the electronic injection solution. The proportion of bifunctional organic dimethacrylate monomer in the total amount of styrene and bifunctional organic dimethacrylate monomer in the electric spraying solution is in direct proportion to the crosslinking degree of the crosslinking structure on the surface of the microsphere, the higher the crosslinking degree is, the larger the crosslinking mesh is, the faster the exchange speed is, but the strength of the crosslinking structure can be reduced to a certain extent, otherwise, the lower the crosslinking degree is, the smaller the crosslinking mesh is, the higher the crosslinking strength is, but the swellability to water is poor; the concentration of bifunctional dimethacrylate organic monomer in the electric spraying solution is too low, the crosslinking degree is low, the bifunctional dimethacrylate organic monomer cannot be applied to melt processing, and too high, the viscosity of a composite system is influenced, and microspheres cannot be formed; the concentration of photoinitiator in the electrospray solution is too low to initiate polymerization of the monomers with too low an initiation efficiency.
In the above-described method, the parameters of electrostatic spraying are: the output voltage of the high-voltage power supply is 10-15 kV, the distance between the spray nozzle and the coagulation bath pool is 7-13 cm, the temperature is 25-50 ℃, the propelling speed of the propelling pump is 1-4 mL/h, the diameter of the propeller is 5-15 mm, and the volume of the propeller is 3-10 mL.
In the above method, after the electrostatic spraying is finished, the hollow porous microspheres coated with titanium dioxide nanoparticles are washed with methanol or ethanol and dried. The hollow porous microspheres of styrene-bifunctional dimethacrylate monomer copolymer are washed and dried to remove impurities on the surfaces of the microspheres in the electrostatic spraying process, such as redundant polymerized monomers, photoinitiators and the like.
The invention mechanism is as follows:
in the prior art, electrostatic spraying is adopted to prepare hollow microspheres which are generally used in the fields of drug slow release and the like, generally, a polymer is dissolved in a solvent for electrostatic spraying to obtain the microspheres, and after the microspheres are obtained by the method, the polymer still can keep the original thermal property and is molten during melt processing, so that the appearance of the microspheres cannot be kept, and the microspheres cannot be used for melt processing. The invention designs a method for preparing hollow porous microspheres coated with titanium dioxide nano particles by electrostatic spraying-photoinitiation polymerization crosslinking, firstly, dissolving a monofunctional styrene monomer, a bifunctional dimethacrylate organic monomer and a photoinitiator in a solvent to prepare an electrospray solution, then adding modified titanium dioxide with double bonds on the surface to mix uniformly, then carrying out electrostatic spraying under a high pressure field to form liquid drops, initiating the styrene monomer, the bifunctional dimethacrylate monomer and the double bonds on the surface of the modified titanium dioxide in the liquid drops by utilizing visible light (according to the initiation wavelength law of the photoinitiator) to carry out free radical polymerization, forming a copolymer containing structural units of the styrene and the bifunctional dimethacrylate monomer on the surface of the titanium dioxide, simultaneously, because of the bifunctional dimethacrylate monomer, molecular chains of the copolymer containing the styrene and the bifunctional dimethacrylate monomer structural units can be mutually cross-linked to form a body-shaped structure, hollow porous microspheres coated with the titanium dioxide nanoparticles are formed in the forming process due to polymerization shrinkage, solvent volatilization and diffusion in a coagulating bath, so that the hollow porous microspheres coated with the titanium dioxide nanoparticles with the melting temperature of more than 530 ℃ and the thermal decomposition temperature of more than 380 ℃ are prepared, and the body-shaped structure formed by cross-linking the molecular chains of the copolymer containing the styrene and the bifunctional dimethacrylate monomer structural units is high in melting temperature, so that a three-dimensional structure can be maintained in the subsequent melting processing process, the functions of the hollow porous microspheres are fully exerted, and the application range of the hollow microsphere structure in actual use is expanded.
The titanium dioxide has good extinction effect (scattering) and good ultraviolet shielding effect (scattering + absorption) of medium-long wave, and the strong ultraviolet resistance of the nano titanium dioxide is due to the fact that the nano titanium dioxide has high refractivity and high optical activity, and the ultraviolet resistance and the mechanism of the ultraviolet resistance are related to the particle size of the nano titanium dioxide: when the particle size is large, the ultraviolet rays are mainly blocked by reflection and scattering, and are effective to ultraviolet rays in both the medium wave region and the long wave region. The porous structure can effectively scatter incident light, and the utilization rate of the incident light is improved. According to the invention, titanium dioxide is coated inside the porous microsphere, light rays pass through the porous structure and enter the surface of the titanium dioxide, and after the light rays are scattered by the titanium dioxide, the light rays are repeatedly scattered between the titanium dioxide and the inner wall of the microsphere, and finally only a small amount of light rays can overflow through the microsphere, so that the extinction effect and the ultraviolet shielding effect are improved. Meanwhile, because the coated polystyrene organic material is more compatible with the high polymer matrix,
has the advantages that:
(1) the hollow porous microsphere coated with the titanium dioxide nanoparticles has the advantages of good extinction effect, good dispersion compatibility, good shielding effect on medium-long wave ultraviolet rays, high melting temperature and thermal degradation temperature, capability of meeting the requirements of general fiber processing and wide application range.
(2) The preparation method of the hollow porous microspheres coated with titanium dioxide nanoparticles has the advantages of simple process, reasonable preparation flow and excellent popularization value.
Drawings
FIG. 1 is a schematic view of a core-shell structure of a hollow porous microsphere of the present invention.
Detailed Description
The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 4:150: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4 hours at 70 ℃, and aging for 11 hours at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 2:1, and the adding amount of the ethanol-water mixed solution is 20% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 30min, and performing reflux reaction for 4h at 60 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 2:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:12, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 5 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 60 ℃, and then vacuum drying at 70 ℃ for 13h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving styrene, Bis-GMA and DMPOH in DMF to obtain an electrospray solution, wherein the weight of Bis-GMA in the electrospray solution accounts for 10 wt% of the total weight of the styrene and the Bis-GMA, the weight of DMF accounts for 50 wt% of the total weight of the styrene and the Bis-GMA, and the weight of DMPOH accounts for 0.5 wt% of the total weight of the styrene and the Bis-GMA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 200rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 400nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 15 percent of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 10kV, the distance between a spray nozzle and a coagulation bath pool is 13cm, the temperature is 25 ℃, the propelling speed of a propelling pump is 4mL/h, the diameter of a propeller is 15mm, and the volume of the propeller is 3 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using methanol after electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method has the structural schematic diagram shown in figure 1, and mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow inside and porous on the surfaces, and have a cross-linked structure formed by cross-linking copolymer molecular chains containing styrene and Bis-GMA structural units, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 500nm, the wall thickness of each cross-linked sphere is 50nm, the diameter of each titanium dioxide nanoparticle is 310nm, the number of the titanium dioxide nanoparticles inside each cross-linked sphere is 1, and the distribution density of surface pores of each cross-linked sphere is 1-10/1000 nm2The aperture of the small hole is 25-30 nm. The hollow porous microspheres coated with titanium dioxide nano particles have the melting temperature of 561 ℃, the thermal decomposition temperature of 410 ℃, good scattering effect on visible light, the breaking strength and the elongation at break of pure PET fibers are 2.45cN/dtex and 58.0 percent, the breaking strength and the elongation at break of the pure PET fibers are 1.59cN/dtex and 0 percent after being radiated for 240 hours under 365nm ultraviolet rays, when the addition amount of the titanium dioxide in the fibers is 2.2 weight percent, full extinction can be achieved, the fineness of the fibers can reach 121dtex, the breaking strength of the prepared fibers is 3.02cN/dtex, the elongation at break is 60.2 percent, and the hollow porous microspheres have good shielding effect on medium-long wave ultraviolet rays,the breaking strength and the breaking elongation of the prepared PET fiber after being radiated for 240 hours under the ultraviolet ray with the wavelength of 365nm are 2.96cN/dtex and 15.3 percent.
Example 2
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 5:200: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4h at 60 ℃, and aging for 10h at room temperature to obtain an aged solution, wherein the volume of ethanol and the added amount in the ethanol-water mixed solution is 30% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 3h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 40min, and performing reflux reaction for 4.5h at 65 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 3:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:11, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 6 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 50 ℃, and then vacuum drying at 80 ℃ for 14h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving styrene, EBPADMA and CQ in trichloromethane to obtain an electrospray solution, wherein the EBPADMA accounts for 15 wt% of the total amount of the styrene and the EBPADMA in the electrospray solution, the trichloromethane accounts for 60 wt% of the total amount of the styrene and the EBPADMA, and the CQ accounts for 0.6 wt% of the total amount of the styrene EBPADMA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 300rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 420nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 20% of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 11kV, the distance between a spray nozzle and a coagulation bath pool is 12cm, the temperature is 30 ℃, the propelling speed of a propelling pump is 3mL/h, the diameter of a propeller is 13mm, and the volume of the propeller is 4 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using ethanol after the electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow inside and porous on the surfaces and have a cross-linked structure, the cross-linked structure is formed by cross-linking copolymer molecular chains containing styrene and Bis-GMA structural units, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 700nm, the wall thickness of each cross-linked sphere is 60nm, the diameter of each titanium dioxide nanoparticle is 330nm, the number of the titanium dioxide nanoparticles inside each cross-linked sphere is 1, and the distribution density of small pores on the surfaces of the cross-linked spheres is 15-25/1000 nm2The aperture of the small hole is 10-18 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have the melting temperature of 532 ℃, the thermal decomposition temperature of 415 ℃, a good scattering effect on visible light, can achieve full extinction when the addition amount of the titanium dioxide in the fibers is 2.2 wt%, the titer of the fibers can reach 112dtex, the fibers have a good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fibers are 3.01cN/dtex and 58.4%, and the breaking strength and the breaking elongation of the fibers after being radiated under the ultraviolet rays with the wavelength of 365nm for 240 hours are 2.95cN/dtex and 14.2%.
Example 3
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 6:250: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4.5h at 65 ℃, and aging for 11h at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 3:1, and the adding amount of the ethanol-water mixed solution is 25% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2.5h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 50min, and performing reflux reaction for 5h at 70 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 4:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:10, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 7 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 70 ℃, and then vacuum drying at 75 ℃ for 12h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving styrene, UDMA and a mixture of DMPOH and CQ (mass ratio of 1:1) in dichloromethane to obtain an electrospraying solution, wherein in the electrospraying solution, the UDMA accounts for 5 wt% of the total amount of the styrene and the UDMA, the dichloromethane accounts for 70 wt% of the total amount of the styrene and the UDMA, and the mixture of DMPOH and CQ accounts for 0.7 wt% of the total amount of the styrene and the UDMA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 400rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 440nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 25 percent of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 12kV, the distance between a spray nozzle and a coagulation bath pool is 11cm, the temperature is 35 ℃, the propelling speed of a propelling pump is 2mL/h, the diameter of a propeller is 11mm, and the volume of the propeller is 5 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using methanol after electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nano particles prepared by the method mainly comprises the titanium dioxide nano particles and cross-linked spheres coated on the surfaces of the titanium dioxide nano particlesThe cross-linked sphere is hollow inside, porous on the surface and has a cross-linked structure, the cross-linked structure is formed by mutual cross-linking of copolymer molecular chains containing styrene and UDMA structural units, titanium dioxide nanoparticles are connected with the cross-linked sphere through covalent bonds, the diameter of the cross-linked sphere is 900nm, the wall thickness of the cross-linked sphere is 70nm, the diameter of the titanium dioxide nanoparticles is 350nm, the number of the titanium dioxide nanoparticles in the cross-linked sphere is 1, and the distribution density of small pores on the surface of the cross-linked sphere is 52-60/1000 nm2The aperture of the small hole is 20-24 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have a melting temperature of 535 ℃, a thermal decomposition temperature of 390 ℃, a good scattering effect on visible light, can achieve full extinction when the addition amount of titanium dioxide in the fibers is 2.0 wt%, the titer of the fibers can reach 121dtex, the fibers have a good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fibers are 3.01cN/dtex and 58.4%, and the breaking strength and the breaking elongation of the fibers after being radiated under 365nm ultraviolet rays for 240 hours are 2.95cN/dtex and 14.2%.
Example 4
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 4:180: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4h at 63 ℃, and aging for 12h at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 4:1, and the addition amount of the ethanol-water mixed solution is 22% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 3h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 60min, and performing reflux reaction for 5h at 60 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 5:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:9, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 8 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 50 ℃, and then vacuum drying at 70 ℃ for 15h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving styrene, TEGDMA and CQ in tetrahydrofuran to obtain an electrospray solution, wherein TEGDMA accounts for 20 wt% of the total amount of the styrene and the TEGDMA in the electrospray solution, the tetrahydrofuran accounts for 80 wt% of the total amount of the styrene and the TEGDMA, and CQ accounts for 0.8 wt% of the total amount of the styrene and the TEGDMA in the electrospray solution;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 500rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 450nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 30% of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 13kV, the distance between a spray nozzle and a coagulation bath pool is 10cm, the temperature is 40 ℃, the propelling speed of a propelling pump is 1mL/h, the diameter of a propeller is 10mm, and the volume of the propeller is 6 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using ethanol after the electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, porous on the surfaces and have a cross-linked structure, the cross-linked structure is formed by mutually cross-linking copolymer molecular chains containing structural units of styrene and TEGDMA, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 1000nm, the wall thickness of each cross-linked sphere is 80nm, the diameter of each titanium dioxide nanoparticle is 300nm, the number of the titanium dioxide nanoparticles in each cross-linked sphere is 2, and the distribution density of surface pores of each cross-linked sphere is 30-55/1000 nm2The aperture of the small hole is 20-30 nm. The melting temperature of the hollow porous microspheres coated with the titanium dioxide nano particles is 540 ℃, the thermal decomposition temperature is 385 ℃, and the visible temperature isThe light has good scattering effect, when the addition amount of the titanium dioxide in the fiber is 2.0 wt%, full extinction can be achieved, the titer of the fiber can reach 120dtex, the fiber has good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fiber are 2.84cN/dtex and 56.3%, and the breaking strength and the breaking elongation of the fiber after being radiated for 240 hours under the ultraviolet ray with the wavelength of 365nm are 2.78cN/dtex and 16.4%.
Example 5
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 5:240: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 5h at 60 ℃, and aging for 12h at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 2:1, and the adding amount of the ethanol-water mixed solution is 28% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2.5h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 35min, and performing reflux reaction for 4h at 65 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 2:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:8, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 9 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 65 ℃, and then vacuum drying at 80 ℃ for 12h to obtain modified titanium dioxide with double bonds on the surface;
(2) styrene, D3Dissolving MA and DMPOH in a mixture (mass ratio of 1:2) of DMF and chloroform to obtain an electrospray solution, and dissolving D in the electrospray solution3MA represents styrene and D325% by weight of the total amount of MA, the mixture of DMF and trichloromethane being based on styrene and D355 wt% of MA, DMPOH in styrene and D30.9 wt% of total MA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at a rotating speed of 250rpm for 1h to uniformly disperse the modified titanium dioxide in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 460nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 35% of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 14kV, the distance between a spray nozzle and a coagulation bath pool is 9cm, the temperature is 45 ℃, the propelling speed of a propelling pump is 2mL/h, the diameter of a propeller is 8mm, and the volume of the propeller is 6 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using methanol after electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and the cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, have porous surfaces and have a cross-linked structure, and the cross-linked structure contains styrene and D3The molecular chains of the copolymer of the MA structural unit are formed by mutual crosslinking, the titanium dioxide nanoparticles are connected with the crosslinking balls through covalent bonds, the diameter of each crosslinking ball is 1250nm, the wall thickness of each crosslinking ball is 90nm, the diameter of each titanium dioxide nanoparticle is 330nm, the number of the titanium dioxide nanoparticles in each crosslinking ball is 3, and the distribution density of small holes on the surface of each crosslinking ball is 1-8/1000 nm2The aperture of the small hole is 10-20 nm. The melting temperature of the hollow porous microspheres coated with the titanium dioxide nano particles is 538 ℃, the thermal decomposition temperature is 400 ℃, the visible light scattering effect is good, when the addition amount of the titanium dioxide in the fiber is 2.2 wt%, the full extinction can be achieved, the titer of the fiber can reach 117dtex, the shielding effect on medium-long wave ultraviolet rays is good, the breaking strength and the breaking elongation of the prepared fiber are 3.02cN/dtex and 59.6%, and the breaking strength and the breaking elongation of the fiber after the fiber is radiated under the ultraviolet ray with the wavelength of 365nm for 240 hours are 2.96cN/dtex and 15.6%.
Example 6
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 6:170: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4 hours at 62 ℃, and aging for 11 hours at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 4:1, and the adding amount of the ethanol-water mixed solution is 24% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 45min, and performing reflux reaction for 4.5h at 70 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 3:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:12, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 10 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 55 ℃, and then vacuum drying at 75 ℃ for 16h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving a mixture of Bis-GMA and EBPADMA (the mass ratio is 2:1) and a mixture of styrene and DMPOH and CQ (the mass ratio is 1:1) in a mixture of dichloromethane and tetrahydrofuran (the mass ratio is 1:2) to obtain an electrospraying solution, wherein the mixture of Bis-GMA and EBPADMA accounts for 20 wt% of the total amount of the mixture of styrene and Bis-GMA and EBPADMA, the mixture of dichloromethane and tetrahydrofuran accounts for 65 wt% of the total amount of the mixture of styrene and Bis-GMA and EBPADMA, and the mixture of DMPOH and CQ accounts for 1.0 wt% of the total amount of the mixture of styrene and Bis-GMA and EBPADMA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 350rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 480nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 40 percent of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 15kV, the distance between a spray nozzle and a coagulation bath pool is 8cm, the temperature is 50 ℃, the propelling speed of a propelling pump is 3mL/h, the diameter of a propeller is 7mm, and the volume of the propeller is 7 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using ethanol after the electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, porous on the surfaces and have a cross-linked structure, the cross-linked structure is formed by mutual cross-linking of copolymer molecular chains containing structural units of styrene and bifunctional dimethacrylate monomers, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 1300nm, the wall thickness of each cross-linked sphere is 100nm, the diameter of each titanium dioxide nanoparticle is 360nm, the number of the titanium dioxide nanoparticles in each cross-linked sphere is 3, and the distribution density of small pores on the surfaces of the cross-linked spheres is 10-15/1000 nm2The aperture of the small hole is 30-40 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have the melting temperature of 545 ℃ and the thermal decomposition temperature of 410 ℃, have a good scattering effect on visible light, can achieve full extinction when the addition amount of the titanium dioxide in the fibers is 2.0 wt%, the titer of the fibers can reach 121dtex, the fibers have a good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fibers are 2.83cN/dtex and 55.9%, and the breaking strength and the breaking elongation of the fibers after being radiated for 240 hours under the ultraviolet rays with the wavelength of 365nm are as follows: 2.78cN/dtex and 14.8%.
Example 7
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 4:230: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4.5h at 65 ℃, and aging for 10h at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 2:1, and the adding amount of the ethanol-water mixed solution is 30% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 3h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 55min, and performing reflux reaction for 4.5h at 60 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 4:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:10, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 9 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 50 ℃, and then vacuum drying at 80 ℃ for 16h to obtain modified titanium dioxide with double bonds on the surface;
(2) combining UDMA with D3Dissolving mixture of MA (mass ratio of 1:2) and styrene and DMPOH in mixture of DMF, chloroform and dichloromethane (mass ratio of 1:1:2) to obtain electrospray solution, and dissolving UDMA and D in the electrospray solution3Mixtures of MA with styrene and UDMA with D35% by weight of the total mixture of MA, the mixture of DMF, trichloromethane and methylene chloride being based on styrene and UDMA and D375 wt% of the total mixture of MA, DMPOH representing styrene and UDMA and D31.1 wt% of the total amount of the mixture of MA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 450rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 500nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 18 percent of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 10kV, the distance between a spray nozzle and a coagulation bath pool is 7cm, the temperature is 25 ℃, the propelling speed of a propelling pump is 1mL/h, the diameter of a propeller is 6mm, and the volume of the propeller is 8 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using methanol after electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, porous on the surfaces and have a cross-linked structure, the cross-linked structure is formed by mutual cross-linking of copolymer molecular chains containing structural units of styrene and bifunctional dimethacrylate monomers, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 1500nm, the wall thickness of each cross-linked sphere is 50nm, the diameter of each titanium dioxide nanoparticle is 300nm, the number of the titanium dioxide nanoparticles in each cross-linked sphere is 3, and the distribution density of small pores on the surfaces of the cross-linked spheres is 14-20/1000 nm2The aperture of the small hole is 60-65 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have the melting temperature of 545 ℃ and the thermal decomposition temperature of 392 ℃, have a good scattering effect on visible light, can achieve full extinction when the addition amount of the titanium dioxide in the fibers is 1.9 wt%, the titer of the fibers can reach 126dtex, the fibers have a good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fibers are 2.69cN/dtex and 54.6%, and the breaking strength and the breaking elongation of the fibers after being radiated under the ultraviolet rays with the wavelength of 365nm for 240 hours are 2.63cN/dtex and 15.9%.
Example 8
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 6:150: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4 hours at 67 ℃, and aging for 12 hours at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 5:1, and the adding amount of the ethanol-water mixed solution is 26% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2.5h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 30min, and performing reflux reaction for 4.5h at 65 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 5:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:12, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 7 percent of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 70 ℃, and then vacuum drying at 70 ℃ for 14h to obtain modified titanium dioxide with double bonds on the surface;
(2) dissolving Bis-GMA, a mixture of EBPADMA and UDMA (the mass ratio is 1:1:1), styrene and CQ in DMF to obtain an electrospray solution, wherein the mixture of Bis-GMA, EBPADMA and UDMA in the electrospray solution accounts for 10 wt% of the total amount of the mixture of styrene, Bis-GMA and EBPADMA and UDMA, the DMF accounts for 80 wt% of the total amount of the mixture of styrene, Bis-GMA and EBPADMA, and the CQ accounts for 1.2 wt% of the total amount of the mixture of styrene, Bis-GMA and EBPADMA and UDMA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 500rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 400nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 27 percent of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 12kV, the distance between a spray nozzle and a coagulation bath pool is 13cm, the temperature is 35 ℃, the propelling speed of a propelling pump is 2mL/h, the diameter of a propeller is 5mm, and the volume of the propeller is 9 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using methanol after electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and the cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, have porous surfaces and have a cross-linked structure, and the cross-linked structure comprises styrene and bifunctional styreneCopolymer molecular chains of the structural unit of the dimethylacrylate monomer are formed by mutual crosslinking, titanium dioxide nanoparticles are connected with crosslinking balls through covalent bonds, the diameter of each crosslinking ball is 1500nm, the wall thickness of each crosslinking ball is 50nm, the diameter of each titanium dioxide nanoparticle is 310nm, the number of the titanium dioxide nanoparticles in each crosslinking ball is 4, and the distribution density of small holes on the surface of each crosslinking ball is 1-5/1000 nm2The aperture of the small hole is 70-80 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have the melting temperature of 550 ℃, the thermal decomposition temperature of 418 ℃, and a good scattering effect on visible light, when the addition amount of the titanium dioxide in the fibers is 2.0 wt%, the full extinction can be achieved, the titer of the fibers can reach 122dtex, the shielding effect on medium-long wave ultraviolet rays is good, the breaking strength and the breaking elongation of the prepared fibers are 2.85cN/dtex and 55.9%, and the breaking strength and the breaking elongation of the fibers after being radiated under 365nm ultraviolet rays for 240 hours are 2.76cN/dtex and 16.4%.
Example 9
A hollow porous microsphere coated with titanium dioxide nanoparticles is prepared by the following steps:
(1) preparing modified titanium dioxide:
a) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid, wherein the mass ratio of the titanium dioxide to the absolute ethyl alcohol to the n-butyl titanate in the mixed dispersion liquid is 4:220: 1;
b) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4 hours at 70 ℃, and aging for 10 hours at room temperature to obtain an aged solution, wherein the mass ratio of ethanol to water in the ethanol-water mixed solution is 3:1, and the adding amount of the ethanol-water mixed solution is 20% of the volume of the mixed dispersion liquid;
c) dropping gamma-methacryloxypropyl trimethoxysilane into an ethanol aqueous solution, stirring and hydrolyzing for 2h at room temperature, adding the mixture into an aging solution subjected to ultrasonic dispersion for 60min, and performing reflux reaction for 4.5h at 70 ℃, wherein the mass ratio of ethanol to water in the ethanol aqueous solution is 5:1, the mass ratio of the gamma-methacryloxypropyl trimethoxysilane to the ethanol aqueous solution is 1:9, and the addition amount of the gamma-methacryloxypropyl trimethoxysilane is 5% of the mass of titanium dioxide in the aging solution;
d) rotary evaporating and drying at 60 ℃, and then vacuum drying at 80 ℃ for 15h to obtain modified titanium dioxide with double bonds on the surface;
(2) mixing UDMA, TEGDMA and D3Dissolving mixture of MA (mass ratio of 1:2:2), styrene and mixture of DMPOH and CQ (mass ratio of 2:1) in chloroform to obtain electrospray solution containing UDMA, TEGDMA and D3Mixture of MA comprising styrene and UDMA, TEGDMA and D325 wt.% of the total mixture of MA, trichloromethane representing styrene and UDMA, TEGDMA and D350 wt% of the total amount of MA mixture, the mixture of DMPOH and CQ comprising styrene and UDMA, TEGDMA and D30.5 wt% of the total amount of the mixture of MA;
(3) adding modified titanium dioxide with double bonds on the surface into an electric spraying solution, mechanically stirring at the rotating speed of 200rpm for 1h to ensure that the modified titanium dioxide is uniformly dispersed in the electric spraying solution, and performing electrostatic spraying under the condition of visible light with the wavelength of 430nm to prepare hollow porous microspheres coated with titanium dioxide nanoparticles, wherein the adding amount of the modified titanium dioxide is 39% of the mass of the electric spraying solution, and the parameters of the electrostatic spraying are as follows: the output voltage of a high-voltage power supply is 14kV, the distance between a spray nozzle and a coagulation bath pool is 10cm, the temperature is 45 ℃, the propelling speed of a propelling pump is 3mL/h, the diameter of a propeller is 15mm, and the volume of the propeller is 10 mL;
(4) and (3) washing the hollow porous microspheres coated with the titanium dioxide nanoparticles by using ethanol after the electrostatic spraying is finished, and drying.
The hollow porous microsphere coated with the titanium dioxide nanoparticles prepared by the method mainly comprises the titanium dioxide nanoparticles and cross-linked spheres coated on the surfaces of the titanium dioxide nanoparticles, wherein the cross-linked spheres are hollow, porous on the surfaces and have a cross-linked structure, the cross-linked structure is formed by mutual cross-linking of copolymer molecular chains containing structural units of styrene and bifunctional dimethacrylate monomers, the titanium dioxide nanoparticles are connected with the cross-linked spheres through covalent bonds, the diameter of each cross-linked sphere is 600nm, the wall thickness of each cross-linked sphere is 100nm, the diameter of each titanium dioxide nanoparticle is 340nm, and the diameter of each titanium dioxide nanoparticle in each cross-linked sphere is 340nmThe number of the cross-linked spheres is 1, and the distribution density of the surface pores of the cross-linked spheres is 30-37/1000 nm2The aperture of the small hole is 10-13 nm. The hollow porous microspheres coated with the titanium dioxide nanoparticles have the melting temperature of 546 ℃, the thermal decomposition temperature of 398 ℃, a good scattering effect on visible light, when the addition amount of titanium dioxide in the fibers is 2.2 wt%, full extinction can be achieved, the titer of the fibers can reach 114dtex, the fibers have a good shielding effect on medium-long wave ultraviolet rays, the breaking strength and the breaking elongation of the prepared fibers are 3.03cN/dtex and 60.7%, and the breaking strength and the breaking elongation of the fibers after being radiated under 365nm ultraviolet rays for 240 hours are 2.97cN/dtex and 17.2%.
Claims (7)
1. A hollow porous microsphere coated with titanium dioxide nanoparticles is characterized in that: mainly comprises titanium dioxide nano-particles and cross-linked spheres coated on the surfaces of the titanium dioxide nano-particles;
the cross-linked sphere is hollow inside, porous in surface and provided with a cross-linked structure, and the cross-linked structure is formed by cross-linking copolymer molecular chains containing styrene and bifunctional dimethacrylate monomer structural units;
the titanium dioxide nano particles are connected with the cross-linked spheres through covalent bonds;
the diameter of the cross-linked ball is 500-1500 nm, and the wall thickness of the cross-linked ball is 50-100 nm; the diameter of the titanium dioxide nano-particles is 300-400 nm; the number of the titanium dioxide nanoparticles in the cross-linked spheres is 1-4;
when the number of the titanium dioxide nanoparticles in the cross-linked ball is less than or equal to 2, the distribution density of pores on the surface of the cross-linked ball is 1-60/1000 nm2The aperture of the small hole is 10-30 nm;
the amount of titanium dioxide nanoparticles inside the crosslinked spheres>2, the distribution density of the pores on the surface of the cross-linked ball is 1-20 pores/1000 nm2The aperture of the small hole is 10-80 nm;
the hollow porous microspheres coated with the titanium dioxide nanoparticles have a melting temperature of more than 530 ℃ and a thermal decomposition temperature of more than 380 ℃.
2. A method for preparing hollow porous microspheres coated with titanium dioxide nanoparticles as claimed in claim 1, characterized by: dissolving styrene, bifunctional dimethacrylate organic monomer and photoinitiator in a solvent to obtain an electric spraying solution, adding modified titanium dioxide with double bonds on the surface into the electric spraying solution for uniform dispersion, and performing electrostatic spraying under the condition of visible light to prepare the hollow porous microspheres coated with titanium dioxide nanoparticles.
3. The method according to claim 2, wherein the uniform dispersion is mechanically stirring at a rotation speed of 200-500 rpm for 1 h; the preparation steps of the modified titanium dioxide are as follows:
(1) dispersing titanium dioxide in absolute ethyl alcohol, ultrasonically stirring, and then dropwise adding n-butyl titanate to obtain a mixed dispersion liquid; the mass ratio of titanium dioxide, absolute ethyl alcohol and n-butyl titanate in the mixed dispersion liquid is 4-6: 150-250: 1;
(2) dropwise adding an ethanol-water mixed solution into the mixed dispersion liquid, reacting for 4-5 h at the temperature of 60-70 ℃, and aging for 10-12 h at room temperature to obtain an aging liquid; the mass ratio of ethanol to water in the ethanol-water mixed solution is 2-5: 1, and the addition amount of the ethanol-water mixed solution is 20-30% of the volume of the mixed dispersion liquid;
(3) dripping a silane coupling agent into an ethanol water solution, stirring and hydrolyzing for 2-3 h at room temperature, adding into an aging solution subjected to ultrasonic dispersion for 30-60 min, and performing reflux reaction for 4-5 h at 60-70 ℃; the mass ratio of ethanol to water in the ethanol aqueous solution is 2-5: 1, the mass ratio of the silane coupling agent to the ethanol aqueous solution is 1: 8-12, the addition amount of the silane coupling agent is 5-10% of the mass of titanium dioxide in the aging liquid, and the silane coupling agent is gamma-methacryloxypropyl trimethoxysilane;
(4) and (3) performing rotary evaporation drying at 50-70 ℃, and then performing vacuum drying at 70-80 ℃ for 12-16 h to obtain the modified titanium dioxide with the surface containing double bonds.
4. The method of claim 2, wherein the step of generating the second signal comprises generating a second signal based on the first signal and the second signalThe bifunctional dimethacrylate organic monomer is Bis-GMA, EBPADMA, UDMA, TEGDMA and D3One or more of MA;
the photoinitiator is DMPOH and/or CQ;
the wavelength of the visible light is 400-500 nm;
the solvent is more than one of DMF, trichloromethane, dichloromethane and tetrahydrofuran.
5. The method of claim 2, wherein the electrospray solution comprises 5-25 wt% of the bifunctional organic methacrylate monomer, 50-80 wt% of the solvent, and 0.5-1.2 wt% of the photoinitiator, based on the total amount of the styrene and the bifunctional organic methacrylate monomer; the adding amount of the modified titanium dioxide is 15-40% of the mass of the electronic injection solution.
6. The method according to claim 2, characterized in that the parameters of electrostatic spraying are: the output voltage of the high-voltage power supply is 10-15 kV, the distance between the spray nozzle and the coagulation bath pool is 7-13 cm, the temperature is 25-50 ℃, the propelling speed of the propelling pump is 1-4 mL/h, the diameter of the propeller is 5-15 mm, and the volume of the propeller is 3-10 mL.
7. The method according to claim 2, wherein the hollow porous microspheres coated with titanium dioxide nanoparticles are washed with methanol or ethanol and dried after the electrostatic spraying is finished.
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| CN1036068C (en) * | 1991-03-22 | 1997-10-08 | 罗姆和哈斯公司 | Method of preparing surface-porous crosslinked copolymer beads |
| CN100567330C (en) * | 2007-12-07 | 2009-12-09 | 北京化工大学 | A kind of preparation method of high-crosslinking-degree hollow polymeric microspheres |
| CN103387717B (en) * | 2012-05-07 | 2015-09-02 | 中国石油化工股份有限公司 | A kind of organic/inorganic composite hollow microballoon and its preparation method and application |
| WO2015054493A1 (en) * | 2013-10-09 | 2015-04-16 | Nanocomposix, Inc. | Encapsulated particles |
| CN104250350A (en) * | 2014-09-30 | 2014-12-31 | 复旦大学 | Method for preparing porous polymer material with through-pore structure |
| CN107540775B (en) * | 2016-06-29 | 2019-10-11 | 中国石油天然气股份有限公司 | A kind of preparation method of organic/inorganic complex carrier |
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