CN1511786A - Continuous Preparation Method of Mesoscopically Ordered Hybrid Silica Fibers - Google Patents

Abstract

The invention relates to a mesoscopically ordered hybrid silica fiber, in particular to a mesoscopically ordered hybrid silica fiber with high strength and high specific surface area combined with sol-gel technology for continuous spinning, and composite optical, Methods for derivatives of electrically, magnetically and catalytically active species. The present invention combines solvent evaporation to induce surfactant self-organization and silica sol-gel process, and prepares continuous hybrid silica fibers through continuous spinning, and removes organic surfactants by high-temperature sintering or solvent extraction. Obtain mesoscopically ordered hybrid silica fibers. By controlling the molecular structure and concentration of surfactants, continuous regulation of mesoscopic structure and size can be achieved. The fiber of the invention not only has good mass transfer performance, but also has good strength and stability of pore size.

Description

Continuous Preparation Method of Mesoscopically Ordered Hybrid Silica Fibers

                      

The invention relates to a mesoscopically ordered hybrid silica fiber, in particular to a mesoscopically ordered hybrid silica fiber with high strength and high specific surface area combined with sol-gel technology for continuous spinning, and composite optical, Methods for derivatives of electrically, magnetically and catalytically active species.

Background technique

Mesoscopically ordered materials are an important research direction of nanomaterials, which refer to the use of surfactants as templates and the use of physical and chemical processes such as sol/gel, emulsification or microemulsion to assemble them through the interface between organic and inorganic substances. A kind of porous material with a pore size between 1.3-30nm, a narrow pore size distribution and a regular pore channel structure generated by a synergistic chemical reaction. In addition to the properties of nanomaterials, mesoscopically ordered materials are also easy to undergo chemical modification and heterogeneous compounding to obtain functional materials. In 1992, researchers from Mobil Corporation successfully synthesized MCM-41 mesoscopically ordered molecular sieves, whose pore size can be adjusted between 1.5-10nm. Its single pore size distribution, high specific surface area and porosity have attracted widespread attention ( C.T. Kresge, M.E. Leonowicz, W.J. Roth, J.C. Vartuli, J.S. Beck, "Ordered mesoporous molecular sieves synthesized by a liquid crystal template mechanism", Nature 1992, 359, 710). Now people can not only use block copolymers or small molecule surfactants as templates to control the size of the pores (D.Zhao, J.Feng, Q.Huo, N.Melosh, G.H.Fredrickson, B.F.Chmelka, G.D.Stucky, "Triblock copolymer Syntheses of mcsoporous silica with periodic50 to 300 angstrom pores”, Science 1998, 279, 548), and can process mesoscopically ordered materials into certain shapes. At present, thin films and microspheres are more researched. Lu et al prepared a porous silica film with a two-dimensional mesoscopic ordered structure by solvent evaporation-induced surfactant self-organization combined with immersion coating technology (Y.Lu, R.Ganguli, C.A.Drewien, M.T.Anderson, C.J.Brinker, W.Gong, Y.Guo, H.Soyez, B.Dunn, M.H.Huang, J.I.Zink, "Continuous formation of supported cubic and hexagonal mesoporous films by sol-gel dip-coating", Nature 1997, 389, 364). Using the combination of surfactant self-organization and aerosol deposition technology, the silica sol system can be made into zero-dimensional mesoscopic ordered submicrospheres. If gold nanoparticles, organic dyes, organic polymers and other functional components are added to the sol, nanocomposites with special functions can be obtained (Y.Lu, H.Fan, A.Stump, T.L.Ward, T.Rieker, C.J.Brinker, "Aerosol-assisted self-assembly of mesostructuredspherical nanoparticles", Nature 1999, 398, 223). In addition, adjusting the composition of the silicon source and introducing organic segments into the inorganic framework can improve the network affinity and network strength of the film or microspheres, and reduce the dielectric constant (Y.Lu, H.Fan, N.Doke, D.A.Loy, R.A.Assink, D.A.Lavan, C.J.Brinker, "Evaporation-induced self-assembly of hybrid bridged silsesquioxane film and particulate mesophases with integral organic functionality", J.Am.Chem.Soc.2000, 122, 5258). However, there are few studies on one-dimensional mesoscopically ordered fibers, and the large specific surface area and good mass transfer properties of fibers make them have wider application prospects in adsorption, catalysis, sensing, and optical waveguides. Huo et al. prepared mesoscopically ordered silica fibers with a length of up to 5 cm in an oil/water two-phase reaction system using the spontaneous growth process after hydrolysis of organosilicon sources (Q. Huo, D. Zhao, J. Feng , K. Weston, S.K. Buratto, G.D. Stucky, S. Schacht, F. Schuth, "Room temperature growth of mesoporous silica fibcrs: a new high-surface-area optical waveguide", Adv. Mater. 1997, 9, 974). Yang et al. prepared mesoscopically ordered silica fibers by drawing glass rods through a sol-gel process (P. Yang, D. Zhao, B. F. Chmelka, G. D. Stucky, "Triblock-copolymer-directed syntheses of large-pore mesoporous silica fibers". Chem. Mater. 1998, 10, 2033). Recently, Jung et al prepared mesoscopically ordered silica fibers with a length of 3-10 cm by centrifugal spinning. (K.T.Jung, Y.H.Chu, S.Haam, Y.G.Shul, "Synthesis of mesoporous silica fiber using spinning method", J.Non-Cryst.Solids, 2002, 298, 193). However, none of these methods can continuously produce silica fibers. Matsuzaki etc. have used the dry spinning method to spin the silica pregel to obtain continuous silica fibers, but there is no mesoscopic ordered structure in this fiber (K.Matsuzaki, D.Arai, N.Taneda , T. Mukaiyama, M. Ikemura, "Continuous silica glass fiber produced by sol-gel process", J.Non-Cryst.Solids 1989, 112, 437). Baskaran etc. have prepared mesoscopically ordered silica fibers in a similar manner, but need to add polymers (such as polyoxyethylene) to improve the viscosity of spinning solution (P.J.Bruinsma, A.Y.Kim, J.Liu, S.Baskaran , "Mesoporous silica synthesized by solvent evaporation: spunfibers and spray-dried hollow spheres", Chem. Mater. 1997, 9, 2507). How to use sol-gel technology to continuously prepare mesoscopic ordered fibers and realize the controllable adjustment of structural characteristics, and how to assemble various active substances on the surface or in the pores of the fibers to make them have special optical, electrical and magnetic properties, It is of great significance to apply these materials to molecular electronics, nonlinear optics, energy storage and conversion, and chemical sensors.

Contents of Invention

The purpose of the present invention is to provide a continuous mesoscopically ordered hybrid silica fiber with special optical, electrical and magnetic properties, which can be controlled and adjusted in structural characteristics, and can assemble various active substances on the fiber surface or in the pores. Preparation.

Another object of the present invention is to provide a use of mesoscopically ordered hybrid silica fibers.

The present invention combines solvent evaporation to induce surfactant self-organization and silica sol-gel process, and prepares continuous hybrid silica fibers by continuous spinning, and removes organic surfactants by high-temperature sintering or solvent extraction Obtain mesoscopically ordered hybrid silica fibers. By controlling the molecular structure and concentration of surfactants, continuous regulation of mesoscopic structure and size can be achieved. The fiber of the invention not only has good mass transfer performance, but also has good strength and stability of pore size. Since the method of the present invention has good compatibility with nanoparticles such as various metals and oxides during the preparation process, a functional system such as a system with catalytic action or photoelectromagnetic properties is introduced into the mesoscopic active system during the preparation process. ordered structure fiber, thereby endowing the mesoscopic ordered hybrid silica fiber of the present invention with functionality.

The present invention involves selecting different organosilicon sources to replace part of silicate Si(OR) ₄ , introducing organic components into the network of silica or the surface of pores, so that the framework of the pores becomes an organic/inorganic hybrid and improves the strength of the framework. Physicochemical properties and affinity selectivity.

The present invention relates to sol-gel processes and continuous spinning processes. The prepared silica pre-gel is extruded from the spinneret, subjected to electrostatic traction or mechanical stretching and traction, and dried to obtain continuous silica fibers. High-temperature sintering or solvent extraction removes surfactants to obtain mesoscopic order. structure to realize the continuous preparation of mesoscopically ordered hybrid silica fibers.

The continuous preparation method of mesoscopically ordered hybrid silica fiber of the present invention, the steps include:

(1). Preparation of silica sol: 208 parts by weight of silicon source, 130-230 parts by weight of ethanol, 18-36 parts by weight of water, 0.005-5 parts by weight of acid catalyst and 48-60 parts by weight of Mix the surfactants evenly, and reflux at 50-70°C to obtain a transparent silica sol;

(2). Preparation of pre-gel: heat the silica sol prepared in step (1) in a water bath at 40-80°C. With the volatilization of ethanol, the concentration of surfactant reaches the critical micelle concentration, and The self-organization process of the surfactant generates a mesoscopic ordered structure with a characteristic size at the nanometer level; the continued volatilization of the solvent leads to a gradual increase in the viscosity of the silica sol and the formation of a pre-gel. The invention controls the ratio of the silicon source and water so that the silicon source is hydrolyzed to form a linear macromolecule, so that the prepared pregel has spinnability.

(3). Continuous preparation of hybrid fibers: Extrude the pre-gel obtained in step (2) through a porous spinneret (the diameter of the spinneret is in the range of 10-500 μm), and pull it in the form of mechanical or electrostatic field acceleration. At the same time, along with ethanol volatilization induced surfactant self-organization and further sol-gel process, continuous hybrid silica fibers were obtained, and the ordered mesoscopic structure formed by surfactant self-organization was formed by the sol-gel process The silica is fixed. The controllable hybrid silica fiber with a diameter of 0.2-100 μm is obtained by adjusting the hole diameter of the spinneret, the drawing speed or the electric field strength.

(4). Preparation of mesoscopically ordered hybrid silica fibers: place the continuous hybrid silica fibers obtained in step (3) in a sintering furnace, and ventilate with air at a speed of 0.1-10°C/min. Heat up to 300-700°C (preferably 450°C) and burn for 0.2-3 hours; or extract the continuous hybrid silica fiber obtained in step (3) with an ethanol solvent to remove the organic surfactant; obtain mesoscopic organic ordered hybrid silica fibers. If necessary, 20-50 parts by weight of polymerizable monomers can be added for polymerization, such as CH ₃ (CH ₂ ) ₁₁ C≡CC≡C-(CH ₂ ) ₈ CO-(OCH ₂ CH ₂ ) ₅ -OH or (C ₂ H ₅ O) ₃ Si-(CH ₂ ) ₆ -CH═CH ₂ etc. to modify the fiber skeleton, adding polymer monomers should be before removing the surfactant.

(5). Preparation of fibers containing metal ions: further immerse the mesoscopically ordered hybrid silica fibers obtained in step (4) in a salt solution containing corresponding metal ions, such as copper nitrate, vanadyl sulfate, silver nitrate Or ferric chloride solution, repeated several times until the fiber contains the designed metal ion content, and the mesoscopic ordered hybrid silica fiber containing metal ions is obtained.

In the transparent silica sol system that step (1) obtains, can further add the functional monomer of 20～50 parts by weight and the initiator of 0.02～0.5 part by weight, or add the functional nanometer metal of 5～30 parts by weight or 5 ~30 parts by weight of nanometer metal oxide particles to obtain functional nanometer silicon dioxide composite material. In addition, soak the mesoscopically ordered hybrid silica fibers obtained in step (4) in an aqueous solution of 1 to 10 parts by weight of biological enzymes, and take them out to obtain biologically active heterogeneous mesoscopically ordered hybrid silica fibers fiber.

The silicon source can be selected from alkoxy-containing monomers, vinyl-containing monomers, organic segment hybrid siloxanes, alkyl-substituted siloxanes, coupling agent silanes or any mixture thereof.

The alkoxy-containing monomers include Si(OCH ₃ ) ₄ , Si(OCH ₂ CH ₃ ) ₄ , Si{OCH(CH ₃ ) ₂ } ₄ or Si(OCH ₂ CH ₂ CH ₂ CH ₃ ) ₄ etc., preferably Si(OCH ₂ CH ₃ ) ₄ or Si{OCH(CH ₃ ) ₂ }4, most preferably Si(OCH ₂ CH ₃ ) ₄ .

The vinyl-containing monomers include CH ₂ =CHSi(OC ₂ H ₅ ) ₃ , CH ₂ =CH(CH ₂ ) ₂ Si(OC ₂ H ₅ ) ₃ or CH ₂ =CH-(CH ₂ ) ₆ - Si(OC ₂ H ₅ ) ₃ etc., preferably CH ₂ =CH-(CH ₂ ) ₆ -Si(OC ₂ H ₅ ) ₃ .

The organic fragment hybrid siloxane includes (CH ₃ CH ₂ O) ₃ Si-CH ₂ -Si(OCH ₂ CH ₃ ) ₃ , (C ₂ H ₅ O) ₃ Si-CH ₂ CH=CHCH ₂ - Si(OC ₂ H ₅ ) ₃ , (CH ₃ CH ₂ O) ₃ Si-C ₆ H ₄ -Si(OCH ₂ CH ₃ ) ₃ or (CH ₃ CH ₂ O) ₃ Si-CH ₂ CH ₂ -Si( OCH ₂ CH ₃ ) ₃ etc., preferably (C ₂ H ₅ O) ₃ Si-C ₆ H ₄ -Si(OC ₂ H ₅ ) ₃ or (CH ₃ CH ₂ O) ₃ Si-CH ₂ CH ₂ -Si( OCH ₂ CH ₃ ) ₃ .

The alkyl-substituted siloxane includes (C ₂ H ₅ O) ₃ Si-CH ₃ , (C ₂ H ₅ O) ₃ Si-(CH ₂ ) ₄ CH ₃ or CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ Si(OC ₂ H ₅ ) ₃ etc., preferably CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ Si(OC ₂ H ₅ ) ₃ .

The coupling agent silanes include NH ₂ CH ₂ Si(OCH ₂ CH ₃ ) ₃ , CH ₂ =C(CH ₃ )COO(CH ₂ ) ₃ Si(OCH ₃ ) ₃ , (CH ₃ O) ₃ Si -(CH ₂ ) ₃ -SH, C ₆ H ₅ NHCH ₂ Si(OCH ₃ ) ₃ or (C ₂ H ₅ O) ₃ SiCH ₂ S ₄ CH ₂ Si(OC ₂ H ₅ ) ₃ etc., preferably (CH ₃ O) ₃ Si-(CH ₂ ) ₃ -SH or CH ₂ =C(CH ₃ )COO(CH ₂ ) ₃ Si(OCH ₃ ) ₃ .

Described surfactant can select small molecule surfactant or copolymer surfactant. Among them, small molecule surfactants include cationic surfactants such as dodecyltrimethylammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethylammonium chloride or dimethyl laurate Aminoethanol ester benzyl ammonium chloride, etc., preferably cetyl trimethyl ammonium bromide or octadecyl trimethyl ammonium chloride; non-ionic surfactants such as fatty alcohol polyoxyethylene ether, pitol mono Laurate, Brij-56{CH ₃ (CH ₂ ) ₁₅ (OCH ₂ CH ₂ ) ₁₀ OH}, Brij-58{CH ₃ (CH ₂ ) ₁₅ (OCH ₂ CH ₂ ) ₂₀ OH}, OP-10 or Span-20, etc., preferably Brij-56 or Brij-58; copolymer surfactants include oxyethylene-oxypropylene copolymers such as Pluronic-123 (PEO ₂₀ -PPO ₇₀ -PEO ₂₀ ), Pluronic-127 (PEO ₂₀ -PPO ₁₀₆ -PEO ₂₀ ), styrene-oxyethylene copolymer, maleic acid-methyl acrylate copolymer or ethyl acrylate-acrylic acid-acrylonitrile copolymer, etc., preferably Pluronic-123 or Pluronic-127.

The catalyst can be selected from any one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid or hydrobromic acid, preferably hydrochloric acid or nitric acid, most preferably nitric acid.

The functional monomers include monomers containing double or triple bonds such as C ₆ H ₄ CH═CH ₂ , CH ₂ ═CHCOO(CH ₂ ) ₁₁ CH ₃ , CH ₃ (CH ₂ ) ₁₁ C≡CC≡C -(CH ₂ ) ₈ CO-(OCH ₂ CH ₂ ) ₅ -OH, CH ₂ =C(CH ₃ )COOCH ₃ or CH ₂ =C(CH ₃ )COOCH ₂ -CH=CH ₂ etc., these monomers The polymerization initiator includes azobisisobutyronitrile, benzoyl peroxide or di-tert-butyl peroxide and the like.

The metal is gold, silver, copper or nickel; the metal oxide is titanium dioxide, vanadium pentoxide, copper oxide, manganese dioxide or iron oxide.

The biological enzyme is any one of glucose oxidase, ascorbate oxidase or lysozyme.

Preparation method and product features of the present invention are as follows:

●The raw materials are extremely cheap, common chemical reagents, such as nitric acid, ethanol, tetraethyl orthosilicate, a common molecular silicon source, etc.

●The experiment is easy to operate.

●Mesoscopically ordered hybrid silica fibers can be continuously prepared by sol-gel technology.

●Supplemented by high-voltage electrospinning technology, fibers that are thinner than those obtained by conventional spinning can be obtained, and the diameter can reach nanometer to submicron level.

●Spinnerets with different hole shapes can be used to obtain special-shaped fibers with different cross-sectional shapes.

●By controlling the concentration of surfactant molecules, the morphology of mesoscopic ordered structures such as nanopores, lamellar or bicontinuous can be controlled. By changing the type of surfactant molecules and adding organic solvents, the continuous adjustment of mesoscopic structure and size can be realized. For example, the pore diameter of nanostructured fibers can be adjusted within the range of 2-30nm.

●By adjusting the composition and structure of silicon source, adding functional components and supplementing different post-processing methods, the shape and function of fibers with mesoscopic order structure can be controlled within a wide range. The organic fragments introduced with the silicon source are different, which can adjust the fiber network affinity and network strength, complex metal ions, adjust the dielectric constant, improve mechanical properties and thermal properties, etc.

●Introduce functional surfactants or monomers (such as diacetylenic surfactants or ethylenic monomers) into the sol system, and obtain nanocomposites through co-condensation with silicon sources or post-polymerization of monomers. In catalysts, bionics , drug controllable release, functional materials and other aspects have important application significance.

●Using the sol/gel method to prepare mesoscopically ordered fibers, not only the raw materials are pure, but also the control of the gel time is simple and effective. The product has high specific surface area, high strength and good pore size stability, and is an excellent catalyst carrier.

The mesoscopic ordered hybrid silica fiber of the present invention can be used to synthesize adsorption materials, catalyst carriers, photoelectric functional materials, and other functional materials, such as conductive materials, optical materials, nonlinear optical materials, biological materials, ordered magnetic materials, molecular devices, etc.

Description of drawings

Fig. 1. transmission electron microscope picture of embodiment 1 of the present invention.

Fig. 2. The transmission electron microscope picture of embodiment 2 of the present invention.

Fig. 3. Transmission electron micrograph of embodiment 3 of the present invention.

Fig. 4. Transmission electron micrograph of embodiment 4 of the present invention.

Figure 5. Transmission electron microscope image of Example 5 of the present invention.

Fig. 6. Transmission electron microscope image of embodiment 8 of the present invention.

Detailed ways

Example 1: Continuous preparation of mesoscopically ordered silica fibers

Mix 208 parts by weight of tetraethyl orthosilicate, 156 parts by weight of ethanol, 36 parts by weight of water, 0.63 parts by weight of nitric acid, and 55 parts by weight of cetyltrimethylammonium bromide, and reflux at 50°C for 90 minutes under electromagnetic stirring , to obtain light yellow transparent silica sol. The prepared silica sol was exposed to a water bath at 70° C. and heated for 2.5 hours until the viscosity increased to form a pre-gel. The silica pregel is extruded through a porous spinneret (the hole diameter is 20 μm), and at the same time, a high-voltage electrostatic field of 2×10 ⁵ V/m is applied for stretching, and continuous silica fibers are obtained after drying. In a sintering furnace with air flowing, the temperature was raised to 450°C at a rate of 1°C/min and burned for 3 hours to remove the surfactant and obtain mesoscopically ordered nanoporous silica fibers with a fiber diameter of 400nm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered nanopores were arranged in a hexagonal arrangement, and the pore size was 2nm. The results of nitrogen adsorption showed that the specific surface area of the fiber was 1250m ² /g. Fibers with finer diameters can be prepared by increasing the electric field strength. As shown in Figure 1.

Example 2: Continuous preparation of mesoscopically ordered silica fibers

Mix 208 parts by weight of tetraethyl orthosilicate, 180 parts by weight of ethanol, 30 parts by weight of water, 0.48 parts by weight of nitric acid, and 52 parts by weight of Brij-58 {CH ₃ (CH ₂ ) ₁₅ (OCH ₂ CH ₂ ) ₂₀ OH} Evenly, reflux at 60°C for 90 minutes under electromagnetic stirring to obtain a colorless and transparent silica sol. Silica fibers were prepared according to the steps in Example 1, with a spinneret hole diameter of 10 μm and a fiber diameter of 320 nm. The results of X-ray diffraction and transmission electron microscopy show that the ordered nanopores are in a cubic arrangement with a pore size of 4nm. The results of nitrogen adsorption show that the specific surface area of the fiber is 710m ² /g. as shown in picture 2.

Example 3: Continuous preparation of mesoscopically ordered silica fibers

Mix 208 parts by weight of tetraethyl orthosilicate, 230 parts by weight of ethanol, 18 parts by weight of water, 0.6 parts by weight of nitric acid, and 48 parts by weight of Pluronic-123 {PEO ₂₀ -PPO ₇₀ -PEO ₂₀ }, and mix them uniformly at 60 Reflux at ℃ for 90 min to obtain a colorless and transparent silica sol. Mesoscopically ordered silica fibers were prepared according to the steps of Example 1, but no electric field was applied, and the fibers were formed by mechanical stretching. The spinneret hole diameter was 100 μm, the stretching rate was 30 cm/min, and the fiber diameter was 5 μm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered nanopores were arranged in a cubic manner, and the pore size was 4nm. The results of nitrogen adsorption showed that the specific surface area of the fiber was 620m ² /g. As shown in Figure 3.

Example 4: Continuous preparation of mesoscopically ordered silica fibers

Mix 208 parts by weight of tetraethyl orthosilicate, 130 parts by weight of ethanol, 36 parts by weight of water, 0.63 parts by weight of nitric acid, and 48 parts by weight of Pluronic-127 {PEO ₂₀ -PPO ₁₀₆ -PEO ₂₀ }. Reflux at ℃ for 90 min to obtain a colorless and transparent silica sol. Mesoscopically ordered silica fibers were prepared according to the steps in Example 3, with a spinneret hole diameter of 500 μm and a fiber diameter of 70 μm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered nanopores were in hexagonal arrangement, and the pore size was 6nm. The results of nitrogen adsorption showed that the specific surface area of the fiber was 480m ² /g. As shown in Figure 4.

Example 5: Continuous preparation of mesoscopically ordered silica fibers

The difference from Example 4 is that 36 parts by weight of the organic solvent 1,3,5-trimethylbenzene was added to the silica sol system, and the size of the ordered nanopores was significantly increased due to its solubilizing effect on the micelles. The resulting fibers had a diameter of 70 µm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered mesopores were in hexagonal arrangement, and the pore size was 30nm. The results of nitrogen adsorption showed that the fiber specific surface area was 350m ² /g. By adjusting the type of surfactant and the amount of organic solvent, the pore size can be continuously adjusted between 2 and 30 nm. As shown in Figure 5.

Example 6: Continuous preparation of mesoscopically ordered silica fibers

The difference from Example 3 is that the surfactant is not removed by sintering, but is removed by extraction in a Soxhlet extractor with ethanol as a solvent, and the fiber diameter is 5 μm. The results of X-ray diffraction and transmission electron microscopy show that the ordered nanopores are in a cubic arrangement with a pore size of 4nm. The results of nitrogen adsorption show that the specific surface area of the fiber is 750m ² /g.

Example 7: Continuous preparation of mesoscopically ordered silica shaped fibers

Different from Example 1, the hole of the spinneret is elliptical, and the fiber is formed by mechanical stretching after the pregel is extruded. The stretching rate is 15cm/min, and the cross section of the fiber is elliptical. Electron microscope results show that the ordered nanopores are arranged in a hexagonal manner, and the pore size is 2nm. The nitrogen adsorption results show that the specific surface area of the fiber is 580m ² /g. Different shapes of spinnerets can be used to prepare special-shaped fibers with different shapes.

Example 8: Continuous preparation of mesoscopically ordered silica concentric tubes

Mix 208 parts by weight of tetraethyl orthosilicate, 170 parts by weight of ethanol, 36 parts by weight of water, 0.5 parts by weight of nitric acid, and 56 parts by weight of Pluronic-123 {PEO ₂₀ -PPO ₇₀ -PEO ₂₀ }, and mix them uniformly at 60 Reflux at ℃ for 90 min to obtain a colorless and transparent silica sol. Silica fibers were prepared according to the steps in Example 1, and the diameter of the fibers was 500 nm. Since the surfactant self-organized into a layered structure, the cross-section of the fiber was observed with a transmission electron microscope, and it was found that the fiber was composed of concentric tubes, and the tube-layer spacing was 5nm. The results of nitrogen adsorption showed that the fiber specific surface area was 580m ² /g. As shown in Figure 6.

Example 9: Continuous preparation of functionalized mesoscopically ordered silica fibers

104 parts by weight of tetraethyl orthosilicate, (CH ₃ CH ₂ O) ₃ Si-CH ₂ CH ₂ -Si(OCH ₂ CH ₃ ) ₃ 177 parts by weight, 160 parts by weight of ethanol, 54 parts by weight of water, 0.63 parts by weight of nitric acid Parts by weight, 30 parts by weight of cetyltrimethylammonium bromide were mixed evenly, and refluxed at 60° C. for 90 minutes under electromagnetic stirring to obtain a light yellow transparent silica sol. Silica fibers were prepared according to the steps in Example 3, the spinneret hole diameter was 200 μm, and the drawing speed was 15 cm/min. The fibers were placed in a sintering furnace, fed with nitrogen, heated to 350°C at a rate of 1°C/min and burned for 3 hours to remove the surfactant and obtain mesoscopically ordered silica fibers with a fiber diameter of 20 μm. The results of X-ray diffraction and transmission electron microscopy show that the ordered nanopores are arranged in a hexagonal arrangement with a pore size of 2nm. The results of nitrogen adsorption show that the specific surface area of the fiber is 970m ² /g. Due to the introduction of the organic segment -Si-CH ₂ CH ₂ -Si-, the lipophilicity and network strength of the inorganic fiber network are improved. Ordered mesoporous fibers with different affinity can be obtained by adjusting the ratio of tetraethyl orthosilicate and (CH ₃ CH ₂ O) ₃ Si-CH ₂ CH ₂ -Si(OCH ₂ CH ₃ ) ₃ .

Example 10: Continuous preparation of functionalized mesoscopically ordered silica fibers

104 parts by weight of tetraethyl orthosilicate, (CH ₃ CH ₂ O) ₃ Si-C ₆ H ₄ -Si(OCH ₂ CH ₃ ) ₃ 201 parts by weight, 156 parts by weight of ethanol, 50 parts by weight of water, 0.54 parts by weight of nitric acid Parts by weight, 30 parts by weight of cetyltrimethylammonium bromide were mixed evenly, and refluxed at 60° C. for 90 minutes under electromagnetic stirring to obtain a light yellow transparent silica sol. Mesoscopically ordered silica fibers were prepared according to the steps in Example 9, and the diameter of the fibers was 20 μm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered nanopores were arranged in a hexagonal arrangement, and the pore size was 2nm. The results of nitrogen adsorption showed that the specific surface area of the fiber was 950m ² /g. The fiber skeleton contains benzene rings. The functionalization of the product can be realized by modifying the benzene ring.

Example 11: Continuous preparation of functionalized mesoscopically ordered silica fibers

The fibers in Example 10 were immersed in 95-98% concentrated sulfuric acid, heated to 85°C, reacted for 3 hours, and then cooled to room temperature. The reacted product was poured into cold water under stirring, and cooled and washed. The fiber can swell in water, indicating that the benzene ring in the fiber skeleton has been modified by sulfonation, which provides conditions for further preparation of functional fibers.

Example 12: Continuous preparation of functionalized mesoscopically ordered silica fibers

The product in Example 11 is immersed in the hydrochloric acid solution of aniline with a concentration of 3% and a pH of 1 to 2. After soaking for a long time, the aniline solution penetrates into the silica fiber, rinses the surface of the fiber with water, and then immediately drops into 3% of the hydrochloric acid solution. Ammonium sulfate solution was reacted for 3 hours to obtain dark green composite fibers. The obtained fiber was repeatedly soaked in water, rinsed, and dried in a vacuum oven at room temperature. Infrared characterization showed that polyaniline in the form of emeraldine salt was formed in the silica fiber, and its room temperature conductivity could reach 4.76×10 ^-4 S/cm. The sulfonic acid group in the fiber has hydrogen ions, which can combine with aniline molecules and play a self-doping role.

Example 13: Continuous preparation of functionalized mesoscopically ordered silica fibers

104 parts by weight of tetraethyl orthosilicate, (CH ₃ O) ₃ Si-CH ₂ CH ₂ CH ₂ -SH 98 parts by weight, 200 parts by weight of ethanol, 34 parts by weight of water, 0.63 parts by weight of nitric acid, Pluronic-123{PEO ₂₀ -PPO ₇₀ -PEO ₂₀ }48 parts by weight were mixed evenly, and refluxed at 60°C for 90 minutes under electromagnetic stirring to obtain a colorless and transparent silica sol. Mesoscopically ordered silica fibers were prepared according to the steps in Example 9, and the diameter of the fibers was 20 μm. The results of X-ray diffraction and transmission electron microscopy showed that the ordered nanopores were arranged in a cubic manner, and the pore size was 4nm. The results of nitrogen adsorption showed that the specific surface area of the fiber was 720m ² /g. The skeleton of the mesoscopic ordered structure fiber synthesized by this method contains mercapto group, which has the function of complexing precious metals such as Ag, Au, Hg, etc., and forms metal/silica nanoporous composite fiber, which has broad application prospects in the field of catalysis.

Example 14: Continuous preparation of functionalized mesoscopically ordered silica fibers

188 parts by weight of tetraethyl orthosilicate, 52 parts by weight of CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ Si(OC ₂ H ₅ ) ₃ , 156 parts by weight of ethanol, 36 parts by weight of water, 0.63 parts by weight of nitric acid, ten Mix 55 parts by weight of hexaalkyltrimethylammonium bromide evenly, and reflux at 70° C. for 90 minutes under electromagnetic stirring to obtain a light yellow transparent silica sol. Mesoscopically ordered silica fibers were prepared according to the steps in Example 9, and the diameter of the fibers was 17 μm. The results of X-ray diffraction and transmission electron microscopy show that the ordered nanopores are arranged in a hexagonal arrangement, and the size of the pores is 2.5nm. The results of nitrogen adsorption show that the specific surface area of the fiber is 900m ² /g. The framework of the mesoscopic ordered structure fiber synthesized by this method contains hydrophobic groups, and a porous material with low dielectric constant can be obtained, which has excellent mechanical and thermal properties, and is of great significance in the new generation of microelectronic devices. In addition, this material can detect trace organic matter in water without being affected by water, and has the characteristics of fast response time and high sensitivity.

Example 15: Continuous preparation of functionalized mesoscopically ordered silica fibers

208 parts by weight of tetraethyl orthosilicate, 156 parts by weight of ethanol, 36 parts by weight of water, 0.63 parts by weight of nitric acid, the surface active diacetylenic molecule CH ₃ (CH ₂ ) ₁₁ C≡CC≡C-(CH ₂ ) ₈ CO-(OCH ₂ CH ₂ ) ₅ -OH 30 parts by weight were mixed evenly, and refluxed at 60°C for 90 minutes under electromagnetic stirring to obtain a colorless and transparent silica sol. Silica fibers were prepared according to the steps in Example 9, and the fiber diameter was 22 μm. Use 0.3 parts by weight of benzoyl peroxide to initiate diacetylene polymerization and sinter at 350°C for 3 hours to obtain organic/inorganic mesoscopically ordered composite functional fibers. Change to show color change characteristics.

Example 16: Continuous preparation of functionalized mesoscopically ordered silica fibers

206 parts by weight of tetraethyl orthosilicate, (C ₂ H ₅ O) ₃ Si-(CH ₂ ) ₆ -CH=CH ₂ 3 parts by weight, organic monomer CH ₂ =CHCOO(CH ₂ ) ₁₁ CH ₃ 2.4 Parts by weight, 1 part by weight of crosslinking agent (CH ₂ =CHCOO) ₂ (CH ₂ ) ₄ , 156 parts by weight of ethanol, 36 parts by weight of water, 0.63 parts by weight of nitric acid, Pluronic-123{PEO ₂₀ -PPO ₇₀ -PEO ₂₀ } 56 parts by weight were uniformly mixed, and refluxed at 60° C. for 90 minutes under electromagnetic stirring to obtain a colorless and transparent silica sol. Continuous spinning according to the steps of Example 1. In this example, the surfactant self-organizes in the form of a lamellar liquid crystal phase. The fiber is placed in a sintering furnace, and nitrogen is blown, and the temperature is raised to 350 ° C at a rate of 1 ° C / min for 3 hours to remove the surfactant. Induces double bond polymerization and crosslinking in the skeleton to form an organic/inorganic alternating layered complex with a layer spacing of 2nm. This structure is similar to the layered structure of a shell, simulating the biomineralization process, and can significantly increase the strength of the fiber and toughness.

Example 17: Continuous preparation of mesoscopically ordered silica fibers containing metal oxides

The difference from Example 1 is that 12 parts of alumina nanoparticles with a diameter of 30nm are added to the sol, the pregel is extruded through a spinneret, and fibers are made under mechanical stretching at a stretching rate of 20cm/min, and dried. Mesoscopically ordered silica fibers were obtained by sintering with a fiber diameter of 10 μm. The surface of the fiber contains alumina, which is expected to be applied in the field of catalysis.

The method is also applicable to the preparation of silica fibers with mesoscopic ordered structure containing nano metal particles such as gold, silver and other nanoparticles, oxides such as zinc oxide, iron oxide and titanium dioxide.

Example 18: Continuous preparation of mesoscopically ordered silica fibers containing metal oxides

The silica fiber with mesoscopic ordered structure prepared in Example 1 was immersed in 2 mol/L vanadyl sulfate solution, so that the nanopores adsorbed vanadium ions. The above process was repeated three times, each time for 3 hours. The adsorbed fibers were placed in a tube furnace, ventilated with air, and sintered at 550° C. for 6 hours, and then naturally cooled to room temperature. The results of X-ray photoelectron spectroscopy show that vanadium pentoxide exists on the surface of the silica nanopores. By adjusting the concentration of vanadyl sulfate and soaking times, the content of vanadium pentoxide on the pore surface can be adjusted.

Example 19: Continuous preparation of metal-containing mesoscopically ordered silica fibers

The silica fibers with mesoporous ordered structure prepared in Example 4 were immersed in 2 mol/L copper nitrate solution, so that the mesoporous fibers adsorbed copper ions. The above process was repeated three times, each time for 3 hours, and each time the pH was adjusted to about 7-8 with a small amount of ammonia water. The fibers adsorbed copper ions were vacuum-dried, placed in a tube furnace, ventilated with air, programmed to heat up to 600°C at a rate of 3°C/min and maintained for 5 hours, and then naturally cooled to room temperature. The appearance of the product was black. The results of X-ray photoelectron spectroscopy show that copper oxide exists on the surface of silica nanopores. The product was reduced with hydrogen at 600°C for half an hour, and then cooled to room temperature while maintaining hydrogen. The results of X-ray photoelectron spectroscopy show that copper exists on the surface of the obtained fiber nanopores.

The method is also applicable to the preparation of mesoscopic ordered silica fibers containing iron oxide, iron-cobalt magnetic materials, silver, manganese, nickel and other metals.

Claims (10)

1. one kind is situated between and sees the preparation method of orderly hydridization silica fiber, and step comprises:

(1). the preparation of silicon dioxide gel: with the silicon source of 208 weight parts, the ethanol of 130～230 weight parts, the water of 18～36 weight parts, the tensio-active agent of the acid catalyst of 0.005～5 weight part and 48～60 weight parts mixes, 50～70 ℃ of backflows, obtain transparent silicon dioxide gel;

(2). the preparation of pre-gelled: the silicon dioxide gel that step (1) is made places 40～80 ℃ of water-baths to heat, and along with the alcoholic acid volatilization, tensio-active agent organizes themselves into ordered structure, and characteristic dimension is in nanometer scale; Continue solvent flashing, cause the viscosity of silicon dioxide gel to increase gradually, form pre-gelled;

(3). the continuous preparation of hybridized fiber: the pre-gelled that step (2) obtains is extruded through the porous spinning jet, stretched, obtain continuous hydridization silica fiber with machinery or electrostatic field acceleration form;

(4). be situated between and see the preparation of orderly hydridization silica fiber: the continuous hydridization silica fiber that step (3) is obtained places in the sintering oven, and blowing air, is warming up to 300～700 ℃ of calcinations with 0.1～10 ℃/minute speed; The continuous hydridization silica fiber that perhaps step (3) is obtained uses alcohol solvent to carry out extracting, removes organic surface active agent; The orderly hydridization silica fiber of sight obtains being situated between.

2. the method for claim 1, it is characterized in that: in the transparent silicon dioxide gel system that step (1) obtains, further add the function monomer of 20～50 weight parts and the initiator of 0.02～0.5 weight part, or add the function nano metal or 5～30 weight part nanometer metal oxide microparticles of 5～30 weight parts, obtain functional nanometer silicon dioxide composite material.

3. the method for claim 1, it is characterized in that: Jie that described step (4) obtains sees orderly hydridization silica fiber and further is immersed in and contains in the respective metal ionic salts solution, repeat to contain in fiber for several times the metal ion content of design, Jie who obtains the implication metal ion sees orderly hydridization silica fiber;

Or Jie of obtaining of described step (4) sees in the aqueous solution that orderly hydridization silica fiber further is immersed in biological enzyme, and heterogeneous Jie who obtains biologically active sees orderly hydridization silica fiber.

4. method as claimed in claim 3 is characterized in that: the salts solution of described metal ion is cupric nitrate, vanadylic sulfate, Silver Nitrate or ferric chloride Solution.

5. the method for claim 1 is characterized in that: add polymerization single polymerization monomer 20～50 weight parts that fiber reinforcement is carried out modification except that tensio-active agent takes a step forward in step (4);

Described polymerization single polymerization monomer is CH ₃(CH ₂) ₁₁C ≡ C-C ≡ C-(CH ₂) ₈CO-(OCH ₂CH ₂) ₅-OH or (C ₂H ₅O) ₃Si-(CH ₂) ₆-CH=CH ₂

6. the method for claim 1 is characterized in that: monomer, vinyl-containing monomers, organic fragment hydridization siloxanes, alkyl that alkoxyl group is selected to contain in described silicon source replace siloxanes, coupling agent one type of silane or their any mixture;

The described monomer that contains alkoxyl group comprises Si (OCH ₃) ₄, Si (OCH ₂CH ₃) ₄, Si{OCH (CH ₃) ₂} ₄Or Si (OCH ₂CH ₂CH ₂CH ₃) ₄

Described vinyl-containing monomers comprises CH ₂=CHSi (OC ₂H ₅) ₃, CH ₂=CH (CH ₂) ₂Si (OC ₂H ₅) ₃Or CH ₂=CH-(CH ₂) ₆-Si (OC ₂H ₅) ₃

Described organic fragment hydridization siloxanes comprises (CH ₃CH ₂O) ₃Si-CH ₂-Si (OCH ₂CH ₃) ₃, (C ₂H ₅O) ₃Si-CH ₂CH=CHCH ₂-Si (OC ₂H ₅) ₃, (CH ₃CH ₂O) ₃Si-C ₆H ₄-Si (OCH ₂CH ₃) ₃Or (CH ₃CH ₂O) ₃Si-CH ₂CH ₂-Si (OCH ₂CH ₃) ₃

Described alkyl replaces siloxanes and comprises (C ₂H ₅O) ₃Si-CH ₃, (C ₂H ₅O) ₃Si-(CH ₂) ₄CH ₃Or CF ₃(CF ₂) ₅CH ₂CH ₂Si (OC ₂H ₅) ₃

Described coupling agent one type of silane comprises NH ₂CH ₂Si (OCH ₂CH ₃) ₃, CH ₂=C (CH ₃) COO (CH ₂) ₃Si (OCH ₃) ₃, (CH ₃O) ₃Si-(CH ₂) ₃-SH, C ₆H ₅NHCH ₂Si (OCH ₃) ₃Or (C ₂H ₅O) ₃SiCH ₂S ₄CH ₂Si (OC ₂H ₅) ₃

7. the method for claim 1, it is characterized in that: described tensio-active agent is Trimethyllaurylammonium bromide, cetyl trimethylammonium bromide, octadecyl trimethyl ammonium chloride, lauric acid dimethylamino-ethanol ester benzyl ammonium chloride, fatty alcohol-polyoxyethylene ether, sorbitan monolaurate, Brij-56{CH ₃(CH ₂) ₁₅(OCH ₂CH ₂) ₁₀OH}, Brij-58{CH ₃(CH ₂) ₁₅(OCH ₂CH ₂) ₂₀OH}, OP-10, Span-20, Pluronic-123 (PEO ₂₀-PPO ₇₀-PEO ₂₀), Pluronic-127 (PEO ₂₀-PPO ₁₀₆-PEO ₂₀), vinylbenzene-oxygen ethylene copolymer, toxilic acid-methyl acrylate copolymer or ethyl propenoate-vinylformic acid-acrylonitrile copolymer;

Described catalyzer is sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid or Hydrogen bromide.

8. method as claimed in claim 2 is characterized in that: described function monomer comprises C ₆H ₄CH=CH ₂, CH ₂=CHCOO (CH ₂) ₁₁CH ₃, CH ₃(CH ₂) ₁₁C ≡ C-C ≡ C-(CH ₂) ₈CO-(OCH ₂CH ₂) ₅-OH, CH ₂=C (CH ₃) COOCH ₃Or CH ₂=C (CH ₃) COOCH ₂-CH=CH ₂

Described initiator is Diisopropyl azodicarboxylate, benzoyl peroxide or ditertiary butyl peroxide;

Described metal is gold and silver, copper or nickel; Described metal oxide is titanium dioxide, Vanadium Pentoxide in FLAKES, cupric oxide, Manganse Dioxide or ferric oxide.

9. method as claimed in claim 3 is characterized in that: described biological enzyme is glucose oxidase, ascorbate salt oxydase or N,O-Diacetylmuramidase.

10. the method for claim 1, it is characterized in that: the aperture of described spinning jet is 10-500 μ m.

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