A process for the preparation of a needle-shaped silica material

Abstract

The application belongs to the field of preparation of silicon dioxide, and particularly relates to a preparation method of needle-shaped silicon dioxide material, and the preparation steps are as follows: S1, preparing an alkaline sodium alginate mixed solution; mixing a sodium alginate aqueous solution, a pH regulator, water, a volatile high-purity alcohol and a polyvinylpyrrolidone n-hexanol solution to form the alkaline sodium alginate mixed solution; S2, adding silicon chloride into the alkaline sodium alginate mixed solution and uniformly mixing, and then standing and reacting for a period of time at a temperature of 40 DEG C to 100 DEG C. The application has the beneficial effects of simple preparation, accurate control of the length-diameter ratio of the needle-shaped silicon dioxide, and suitability for actual batch production in industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon dioxide functional materials, and particularly relates to a preparation method of acicular silicon dioxide material. BACKGROUND

[0002] In recent years, new types of silicon dioxide materials have been continuously applied in the fields of biomedical imaging, targeted drug delivery systems and trace detection, and the acicular structure with high aspect ratio has attracted much attention due to its unique anisotropic characteristics.

[0003] For example, in the rubber industry, the acicular silicon dioxide can significantly improve the wear resistance (30-50% higher than traditional carbon black fillers) and wet skid resistance of green tires through axial orientation arrangement, while maintaining the color stability of the products, and solving the coloring limitation problem caused by traditional reinforcing agents. For example, in the field of electronic packaging, the high aspect ratio (≥30:1) and small tip curvature radius (<5 nm) characteristics enable it to be used as a sealing material for organic electroluminescent devices (OELD), and through surface modification, it can achieve room temperature rapid curing, and significantly improve the sealing performance and service life of the device. For example, in the application of optical coating, the three-dimensional porous network structure formed by the acicular silicon dioxide and spherical nanoparticles can improve the light transmittance of the substrate by more than 2%, and endow the surface with superhydrophilicity (static water contact angle <50°), which is suitable for high-performance antireflection films and self-cleaning coatings. For example, in the biomedical field, the axial extension structure and high specific surface area (>200 m2 / g) characteristics are used as drug controlled release carriers to achieve targeted delivery and sustained release effect, and in bone tissue engineering applications, it can guide the directional growth of cells and promote the bone repair rate to increase by 40%.

[0004] Due to the unique anisotropic characteristics of acicular silicon dioxide, it has shown significant advantages in the field of functional materials, and therefore its research and development have been paid more and more attention.

[0005] However, the traditional preparation method of silicon dioxide still has many bottlenecks in process complexity, morphology control precision and environmental protection, etc. For example, the traditional template method uses gold and silver nanowires as hard templates, and after coating a silicon layer by vapor deposition, a strong corrosive agent such as aqua regia is needed to remove the template, which not only produces waste liquid containing heavy metals, but also causes the final product to have defects such as uneven diameter (20-50 nm) and high surface defect density.

[0006] Of course, there are some companies currently developed some new preparation method of silicon dioxide material, for example, sol-gel method, but the preparation process is complex, the preparation cost is high, which is not conducive to industrial production. For example, refer to the patent with the publication number CN105060306A, which uses sol-gel method, drops the mixed solution of tetraethyl orthosilicate and anhydrous ethanol into anhydrous ethanol added with tellurium nanowires, stirs, dries and calcines to obtain SiO2 wire, which has the advantage of not needing complex vacuum equipment and corrosive liquid, but this method is based on another tellurium wire, which makes the method steps too complicated and increases the preparation cost. Therefore, developing an environmentally friendly, precise and controllable new preparation process has become a technical problem to be solved in this field. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art, provide a preparation method of needle-shaped silicon dioxide material, solve the technical problems of complex preparation process, poor controllability, low repeatability and high cost in the prior art.

[0008] The purpose of the present application is to simplify the preparation process, and at the same time, to control the needle-shaped silicon dioxide well, so as to be more conducive to low-cost, high-quality mass industrial production.

[0009] The purpose of the present application is achieved by the following technical scheme: a preparation method of needle-shaped silicon dioxide material, the preparation steps are as follows:

[0010] S1, preparing an alkaline sodium alginate mixed solution;

[0011] Mixing the sodium alginate aqueous solution, the pH adjuster, the water, the dispersant and the polyvinylpyrrolidone solution to form an alkaline sodium alginate mixed solution;

[0012] S2, adding silicon chloride to the alkaline sodium alginate mixed solution and mixing uniformly, and then standing for a period of time at a temperature of 40-100 DEG C;

[0013] S3, after the standing reaction is finished, washing the white product after washing with a mixed solution of deionized water and ethanol, and drying to obtain a needle-shaped silicon dioxide sample.

[0014] Further, the pH adjuster is ammonia water.

[0015] Further, the volatile high-purity alcohol is one or more of ethanol or methanol.

[0016] Further, the solution of polyvinylpyrrolidone is a n-hexanol solution of polyvinylpyrrolidone.

[0017] Further, the concentration of the sodium alginate aqueous solution is 0.18mol / L-0.31mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution is 50.00mg / mL-500.00mg / mL, and the volume ratio of the sodium alginate aqueous solution, the pH regulator, water, the volatile high-purity alcohol and the polyvinylpyrrolidone n-hexanol solution is (1-3):(1-4):(3-8):(10-20):100.

[0018] Further, the volume ratio of the silicon chloride and the polyvinylpyrrolidone n-hexanol solution is (1-10):200.

[0019] Further, in S2, the standing reaction time is 20min-15h.

[0020] Further, in the preparation:

[0021] The concentration of the sodium alginate aqueous solution is 0.18mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution is 50.00mg / mL, the volume ratio of the sodium alginate aqueous solution, the pH regulator, water, the volatile high-purity alcohol and the polyvinylpyrrolidone n-hexanol solution is 1:1:3:10:100, the volume ratio of the silicon chloride and the polyvinylpyrrolidone n-hexanol solution is 10:200, and the reaction in S2 is carried out at a temperature environment of 40℃ for 15h.

[0022] Alternatively, the concentration of the sodium alginate aqueous solution is 0.18mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution is 200.00mg / mL, the volume ratio of the sodium alginate aqueous solution, the pH regulator, water, the volatile high-purity alcohol and the polyvinylpyrrolidone n-hexanol solution is 1:1:3:10:100, the volume ratio of the silicon chloride and the polyvinylpyrrolidone n-hexanol solution is 1:200, and the reaction in S2 is carried out at a temperature environment of 60℃ for 4h.

[0023] Alternatively, the concentration of the sodium alginate aqueous solution is 0.31mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution is 500.00mg / mL, the volume ratio of the sodium alginate aqueous solution, the pH regulator, water, the volatile high-purity alcohol and the polyvinylpyrrolidone n-hexanol solution is 3:4:8:20:100, the volume ratio of the silicon chloride and the polyvinylpyrrolidone n-hexanol solution is 1:200, and the reaction in S2 is carried out at a temperature environment of 100℃ for 20min.

[0024] The application has the following advantages:

[0025] (1) The whole process is very simple;

[0026] (2) By controlling the concentration of polyvinylpyrrolidone n-hexanol, by controlling the standing reaction time, the aspect ratio of the needle-shaped silica sample can be accurately controlled very conveniently;

[0027] (3) Because the preparation process is simple, the preparation cost is low, and because the aspect ratio of the product can be accurately controlled very conveniently, it is very suitable for actual batch production in industry. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 X-ray diffraction pattern of the needle-shaped silica sample prepared in Example 1;

[0029] Figure 2 Optical microscope general morphology photo of the needle-shaped silica sample prepared in Example 1;

[0030] Figure 3 Optical microscope single needle morphology photo of the needle-shaped silica sample prepared in Example 1;

[0031] Figure 4 Relationship diagram of the aspect ratio of the needle-shaped silica sample and the concentration of polyvinylpyrrolidone n-hexanol solution;

[0032] Figure 5 Relationship diagram of the aspect ratio of the needle-shaped silica sample and the reaction standing time. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the drawings, but the protection scope of the application is not limited to the following description.

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0035] A preparation method of needle-shaped silica material is disclosed in the present scheme, and the preparation steps are as follows:

[0036] S1, preparing an alkaline sodium alginate mixed solution;

[0037] The sodium alginate aqueous solution, the pH adjuster, the water, the dispersant and the polyvinylpyrrolidone solution are mixed to form an alkaline sodium alginate mixed solution with a concentration of 0.18 mol / L to 0.31 mol / L;

[0038] The volume ratio of the sodium alginate aqueous solution, the pH regulator, the water, the dispersant, and the polyvinylpyrrolidone solution is (1-3):(1-4):(3-8):(10-20):100.

[0039] The concentration of the polyvinylpyrrolidone solution is 50.00 mg / mL-500.00 mg / mL.

[0040] S2, the silicon chloride is added to the alkaline sodium alginate mixed solution, and then the mixture is uniformly mixed, and then the reaction is carried out at a temperature of 40-100 DEG C for 20 min-15 h.

[0041] The volume ratio of the silicon chloride and the polyvinylpyrrolidone solution is (1-10):200.

[0042] S3, after the reaction is completed, the white product is washed with a mixed solution of deionized water and ethanol, and then dried to obtain a needle-shaped silicon dioxide sample.

[0043] In the present scheme, the pH regulator can be ammonia, NaOH, etc., the easily volatile high-purity alcohol can be absolute ethanol, absolute methanol, etc., and the polyvinylpyrrolidone solution is polyvinylpyrrolidone n-hexanol solution.

[0044] The present scheme is further described below through specific examples.

[0045] Example 1

[0046] The present embodiment discloses a preparation method of a needle-shaped silicon dioxide material, and the preparation steps are as follows:

[0047] S1, an alkaline sodium alginate mixed solution is prepared;

[0048] The sodium alginate powder is weighed and added to a beaker containing ionized water, and then magnetically stirred to prepare a sodium alginate solution with a concentration of 0.18 mol / L;

[0049] The polyvinylpyrrolidone is weighed and added to n-hexanol, and then magnetically stirred to prepare a polyvinylpyrrolidone n-hexanol solution with a concentration of 200.00 mg / mL;

[0050] S2, a) sodium alginate aqueous solution, ammonia, water, absolute ethanol, and polyvinylpyrrolidone n-hexanol solution are weighed according to the volume ratio of 1:1:3:10:100;

[0051] b) the sodium alginate aqueous solution is poured into the polyvinylpyrrolidone n-hexanol solution, and then magnetically stirred to obtain a transparent solution;

[0052] Then, the absolute ethanol and water are added to the above transparent solution, and then stirred uniformly;

[0053] Then, ammonia water is added in a volume ratio of 1:200 of the chlorosilicon solution to the polyvinylpyrrolidone n-hexanol solution;

[0054] c) Immediately after adding the ammonia water in step b), chlorosilicon is added, and then the mixture is stirred and mixed uniformly;

[0055] Then, the mixture is placed in an oven at 60°C (the temperature range is the same) for 4 hours (the time range is the same);

[0056] S3, after the standing is completed, the dried substance is washed with a mixed solution of deionized water and ethanol for 3 times, and then the washed white product is dried to obtain a needle-shaped silicon dioxide sample.

[0057] It should be noted that the morphology of the needle-shaped silicon dioxide sample prepared in Example 1 is detected, and the detection shows that the needle-shaped silicon dioxide sample is 100-200 microns, and the aspect ratio is about 10.2.

[0058] Example 2

[0059] The concentration of the polyvinylpyrrolidone n-hexanol solution in Example 1 is changed to 50 mg / mL, and the rest of the reaction process and reaction conditions remain unchanged. A needle-shaped silicon dioxide sample with an aspect ratio of about 20.1 can be obtained.

[0060] Example 3

[0061] The concentration of the polyvinylpyrrolidone n-hexanol solution in Example 1 is changed to 500 mg / mL, and the rest of the reaction process and reaction conditions remain unchanged. A needle-shaped silicon dioxide sample with an aspect ratio of about 2.9 can be obtained.

[0062] It should be noted that the difference between Example 1, Example 2, and Example 3 is the different concentrations of the polyvinylpyrrolidone n-hexanol solution. The morphology of the needle-shaped silicon dioxide sample prepared in Example 1, Example 2, and Example 3 is detected, and a graph showing the relationship between the concentration of the polyvinylpyrrolidone n-hexanol solution and the aspect ratio of the needle-shaped silicon dioxide sample is drawn, as shown in Figure 4 .

[0063] From Figure 4 It can be seen that: (1) as the concentration of the polyvinylpyrrolidone n-hexanol solution decreases, the aspect ratio of the needle-shaped silicon dioxide sample gradually increases; (2) as the concentration of the polyvinylpyrrolidone n-hexanol solution increases, the aspect ratio of the needle-shaped silicon dioxide sample gradually decreases.

[0064] Example 4

[0065] The reaction time in Example 1 is changed to 15 hours, and the rest of the reaction process and reaction conditions remain unchanged. The sample of needle-shaped silicon dioxide with an aspect ratio of about 23.3 can be obtained.

[0066] Example 5

[0067] The reaction time in Example 1 is changed to 40 minutes, and the rest of the reaction process and reaction conditions remain unchanged. The sample of needle-shaped silicon dioxide with an aspect ratio of about 3.5 can be obtained.

[0068] It should be noted that: Example 1, Example 4, Example 5 are different standing reaction time, the influence of the aspect ratio of the sample of needle-shaped silicon dioxide. The morphology of the sample of needle-shaped silicon dioxide prepared in Example 1, Example 4, Example 5 is detected, and a graph showing the relationship between the different standing reaction time and the aspect ratio of the sample of needle-shaped silicon dioxide is drawn, see Figure 5 .

[0069] From Figure 5 It can be seen that: (1) As the standing reaction time becomes longer, the aspect ratio of the sample of needle-shaped silicon dioxide gradually increases; (2) As the standing reaction time becomes shorter, the aspect ratio of the sample of needle-shaped silicon dioxide gradually decreases.

[0070] Example 6

[0071] This embodiment is consistent with Example 1, and the difference is that:

[0072] During preparation, the concentration of the sodium alginate aqueous solution used is 0.18 mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution used is 50.00 mg / mL, the volume ratio of the sodium alginate aqueous solution, the pH adjuster, water, the easily volatile high-purity alcohol, and the polyvinylpyrrolidone n-hexanol solution used is 1:1:3:10:100, and the volume ratio of the silicon chloride to the polyvinylpyrrolidone n-hexanol solution used is 10:200, and the reaction in S2 is carried out at a temperature environment of 40℃ for 15h.

[0073] Example 7

[0074] This embodiment is consistent with Example 1, and the difference is that:

[0075] During preparation, the concentration of the sodium alginate aqueous solution used is 0.31 mol / L, the concentration of the polyvinylpyrrolidone n-hexanol solution used is 500.00 mg / mL, the volume ratio of the sodium alginate aqueous solution, the pH adjuster, water, the easily volatile high-purity alcohol, and the polyvinylpyrrolidone n-hexanol solution used is 3:4:8:20:100, and the volume ratio of the silicon chloride to the polyvinylpyrrolidone n-hexanol solution used is 1:200, and the reaction in S2 is carried out at a temperature environment of 100℃ for 20min.

[0076] Test Example

[0077] The product prepared in Example 1 was subjected to X-ray detection, and the X-ray diffraction spectrum thereof is shown in Figure 1

[0078] The product prepared in Example 1 was subjected to optical microscope observation, and the general morphology photo of the optical microscope thereof is shown in Figure 2 , and the single needle morphology photo of the optical microscope thereof is shown in Figure 3 .

[0079] In summary: it can be seen from the examples that (1) the preparation process of the scheme is relatively simple (low cost); (2) and by adjusting the concentration of polyvinylpyrrolidone in n-hexanol, adjusting the standing reaction, the aspect ratio of the needle-shaped silicon dioxide sample can be accurately controlled (easy to control); (3) Therefore, it can be said that the scheme not only has low cost, but also can effectively control the aspect ratio of the product, so it is suitable for actual batch production in the industrial field.

[0080] The above examples only express the preferred embodiments, which are described in detail, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.​

Claims

1. A method for preparing needle-like silica material, characterized in that: The preparation steps are as follows: S1. Prepare an alkaline sodium alginate mixed solution; Sodium alginate aqueous solution, pH adjuster, water, dispersant, and polyvinylpyrrolidone solution are mixed to form an alkaline sodium alginate mixed solution; wherein, the polyvinylpyrrolidone solution is a hexanol solution of polyvinylpyrrolidone, and the dispersant is a volatile high-purity alcohol; The volume ratio of sodium alginate aqueous solution, pH adjuster, water, volatile high-purity alcohol, and polyvinylpyrrolidone hexanol solution is (1~3):(1~4):(3~8):(10~20):

100. The concentration of sodium alginate aqueous solution is 0.18 mol / L to 0.31 mol / L, and the concentration of polyvinylpyrrolidone n-hexanol solution is 50.00 mg / mL to 500.00 mg / mL. S2. Add silicon chloride to the alkaline sodium alginate mixed solution and mix well. Then let it stand for a period of time at a temperature of 40℃~100℃. S3. After the static reaction is complete, wash the product multiple times with a mixed solution of deionized water and ethanol, and then dry the washed white product to obtain a needle-shaped silica sample.

2. The method for preparing needle-shaped silica material according to claim 1, characterized in that: The pH adjuster is ammonia.

3. The method for preparing needle-shaped silica material according to claim 2, characterized in that: The volatile, high-purity alcohol is one or more of ethanol or methanol.

4. A method for preparing a needle-like silica material according to any one of claims 1 to 3, characterized in that: The silicon chloride and polyvinylpyrrolidone hexanol solution are in a volume ratio of (1~10):

200.

5. The method for preparing a needle-like silica material according to claim 4, characterized in that: In the S2 process, the static reaction time is 40 min to 15 h.

6. The method for preparing a needle-like silica material according to claim 5, characterized in that: During preparation: The concentration of sodium alginate aqueous solution used was 0.18 mol / L, the concentration of polyvinylpyrrolidone n-hexanol solution used was 50.00 mg / mL, the volume ratio of sodium alginate aqueous solution, pH adjuster, water, volatile high-purity alcohol, and polyvinylpyrrolidone n-hexanol solution used was 1:1:3:10:100, and the volume ratio of silicon chloride to polyvinylpyrrolidone n-hexanol solution used was 10:

200. The reaction was carried out in S2 at a temperature of 40℃ for 15 h. Alternatively, the concentration of sodium alginate aqueous solution is 0.18 mol / L, the concentration of polyvinylpyrrolidone n-hexanol solution is 200.00 mg / mL, the volume ratio of sodium alginate aqueous solution, pH adjuster, water, volatile high-purity alcohol, and polyvinylpyrrolidone n-hexanol solution is 1:1:3:10:100, and the volume ratio of silicon chloride to polyvinylpyrrolidone n-hexanol solution is 1:

200. The reaction is carried out in S2 at a temperature of 60°C for 4 hours. Alternatively, the concentration of sodium alginate aqueous solution is 0.31 mol / L, the concentration of polyvinylpyrrolidone n-hexanol solution is 500.00 mg / mL, the volume ratio of sodium alginate aqueous solution, pH adjuster, water, volatile high-purity alcohol, and polyvinylpyrrolidone n-hexanol solution is 3:4:8:20:100, and the volume ratio of silicon chloride to polyvinylpyrrolidone n-hexanol solution is 1:

200. The reaction is carried out in S2 at a temperature of 100°C for 20 min.

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