Micron-sized silicon oxide particles and preparation method thereof

Abstract

The invention relates to micron-sized silicon oxide particles and a preparation method thereof, and the preparation method comprises the following steps: grafting sulfydryl on first silicon oxide particles to obtain silicon oxide particles containing sulfydryl on the surfaces, and grafting epoxy groups on second silicon oxide particles to obtain silicon oxide particles containing epoxy groups on the surfaces, the particle sizes of the first silicon oxide particles and the second silicon oxide particles are smaller than or equal to 100 nm, and the difference between the particle sizes of the first silicon oxide particles and the second silicon oxide particles is within 30 nm; and mixing the silicon oxide particles containing sulfydryl on the surfaces, the silicon oxide particles containing epoxy groups on the surfaces and a basic catalyst, and carrying out click chemical reaction to obtain the micron-sized silicon oxide particles. The preparation method is mild in reaction condition, rapid in reaction and environmentally friendly, the obtained micron-sized silicon oxide particles are large in specific surface area, and groups which can be used for further modification or functionalization are still reserved on the surfaces of the micron-sized silicon oxide particles.

Description

Technical Field

[0001] The invention relates to the technical field of micron materials, in particular to micron-sized silicon oxide particles and a preparation method thereof. Background Art

[0002] At present, the methods for preparing micron-sized silicon oxide particles include seed growth method, template method, emulsion method, etc. Among them, the seed growth method often requires the preparation of submicron-sized crystal nuclei first, and then grows into micron-sized particles. Therefore, this method has the problems of long production cycle and low growth efficiency; the template method usually uses a hard template or a soft template as a seed, and then grows silicon oxide particles on its surface until it grows to the target particle size. In order to avoid the influence of the template on subsequent use, it is also necessary to use high temperature, chemical reaction, solvent dissolution and other methods to remove the template, resulting in high production costs. In addition, the removal of the template may also cause the silicon oxide microspheres to collapse and deform; the emulsion process often uses a large amount of organic matter in production, which has the problems of high production costs and easy environmental pollution. Summary of the invention

[0003] Based on this, it is necessary to provide a micron-sized silicon oxide particle and a preparation method thereof to address the above-mentioned problems. The preparation method not only has a short growth cycle, mild reaction conditions, and is green and environmentally friendly, but also the obtained micron-sized silicon oxide particles have a large specific surface area and groups that can be used for further modification or functionalization.

[0004] A method for preparing micron-sized silicon oxide particles comprises the following steps:

[0005] Grafting mercapto groups on first silicon oxide particles to obtain silicon oxide particles having mercapto groups on the surface, and grafting epoxy groups on second silicon oxide particles to obtain silicon oxide particles having epoxy groups on the surface, wherein the particle sizes of the first silicon oxide particles and the second silicon oxide particles are both less than or equal to 100 nm, and the particle sizes of the first silicon oxide particles and the second silicon oxide particles differ by less than 30 nm;

[0006] The silicon oxide particles containing mercapto groups on the surface, the silicon oxide particles containing epoxy groups on the surface and an alkaline catalyst are mixed and subjected to a click chemical reaction to obtain micron-sized silicon oxide particles.

[0007] In one embodiment, the first silicon oxide particles and the second silicon oxide particles satisfy at least one of the following relationships:

[0008] (1) The particle sizes of the first silicon oxide particles and the second silicon oxide particles differ by less than 20 nm;

[0009] (2) The particle sizes of the first silicon oxide particles and the second silicon oxide particles are independently selected from 20 nm to 60 nm.

[0010] In one embodiment, a mercapto group-containing silane coupling agent is used to graft mercapto groups onto the first silicon oxide particles.

[0011] In one embodiment, the mercapto-containing silane coupling agent is selected from at least one of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

[0012] In one embodiment, epoxy groups are grafted onto the second silicon oxide particles using a silane coupling agent containing epoxy groups.

[0013] In one embodiment, the epoxy-containing silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldiethoxysilane and γ-glycidoxypropylchlorosilane.

[0014] In one embodiment, the step of mixing the silicon oxide particles having mercapto groups on the surface, the silicon oxide particles having epoxy groups on the surface, and the alkaline catalyst satisfies at least one of the following conditions:

[0015] (1) The amount of the silicon oxide particles containing mercapto groups on the surface and the silicon oxide particles containing epoxy groups on the surface is based on the molar ratio of mercapto groups to epoxy groups, wherein the molar ratio of mercapto groups to epoxy groups is 1.5:1-1:1;

[0016] (2) The alkaline catalyst is selected from LiOH, K 2 CO 3 , KOH, and tetrabutylammonium fluoride.

[0017] In one embodiment, the click chemistry reaction is carried out at a temperature of 80°C-95°C and for a time of 2h-4h.

[0018] Micron-sized silicon oxide particles are obtained by adopting the preparation method.

[0019] In one embodiment, the particle size of the micron-sized silicon oxide particles is 1 μm-2 μm.

[0020] The present invention first grafts mercapto groups and epoxy groups onto the surface of small-sized silicon oxide particles, respectively, and then promotes the bulk assembly of small-sized silicon oxide particles layer by layer under relatively mild conditions through the nucleophilic ring-opening reaction between mercapto groups and epoxy groups, thereby obtaining micron-sized silicon oxide particles. The preparation method has mild reaction conditions, rapid reaction, and is green and environmentally friendly. The obtained micron-sized silicon oxide particles not only have a large specific surface area, but also retain mercapto groups that have not participated in the reaction on the surface, and even retain alkyl groups obtained by ring-opening of epoxy groups, which can be used for further modification or functionalization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is the SEM image of the product of Example 1;

[0023] Figure 2 This is the SEM image of the product of Comparative Example 1. DETAILED DESCRIPTION

[0024] For ease of understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

[0026] In the present invention, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0027] The preparation method of micron-sized silicon oxide particles provided by the present invention comprises: grafting mercapto groups on first silicon oxide particles to obtain silicon oxide particles containing mercapto groups on the surface, grafting epoxy groups on second silicon oxide particles to obtain silicon oxide particles containing epoxy groups on the surface, and then mixing the silicon oxide particles containing mercapto groups on the surface, the silicon oxide particles containing epoxy groups on the surface, and an alkaline catalyst and performing a click chemistry reaction to obtain micron-sized silicon oxide particles.

[0028] Using self-assembly technology to obtain target products with specific structures requires the coordination of multiple factors, such as solvents, external fields, temperature, etc. The process is relatively complex. Even the same material will produce different assembly results, with different morphologies and properties due to different assembly conditions. Therefore, it is difficult to find universal laws like chemical reaction equations to control the self-assembly process and results for many self-assembly reactions.

[0029] The present invention utilizes the high selectivity between thiol and epoxy groups, uses chemical reaction as the driving force for self-assembly, and uses steric hindrance as the termination condition for self-aggregation. While growing efficiently, the size of the particles can be effectively controlled, making the self-assembly process controllable. Specifically, the principle and chemical reaction equation of the click chemistry reaction of mixing the silicon oxide particles containing thiol groups on the surface, the silicon oxide particles containing epoxy groups on the surface, and the alkaline catalyst can be summarized as follows, wherein R in the chemical reaction equation is 1 represents the first silicon oxide particle, R 2 represents second silicon oxide particles, and B represents a basic catalyst.

[0030] First, in the silicon oxide particles containing mercapto groups on the surface, the mercapto functional groups lose hydrogen ions under the action of the alkaline catalyst to form thiol anions and the conjugate acid of the catalyst (reaction 1).

[0031] Reaction 1:

[0032] Secondly, the thiol anion acts as a nucleophile to attack the silicon oxide particles containing epoxy groups on the surface, specifically attacking the carbon atom with small steric hindrance on the epoxy functional group, opening the epoxy functional group and forming an alkoxide anion intermediate (reaction 2).

[0033] Reaction 2:

[0034] The alkoxide anion intermediate product generated in reaction two has a very strong alkalinity (pKa ~ 17), which can capture the hydrogen ions of the thiol functional group in the reaction system (reaction three) and the hydrogen ions of the catalyst conjugate acid (reaction four) to form the final product, wherein when the alkoxide anion intermediate product captures the hydrogen ions of the thiol functional group (reaction three), the generated thiol anion can continue to nucleophilically attack the unreacted epoxy functional group, i.e., repeating reaction two, and when the alkoxide anion intermediate product captures the hydrogen ions of the catalyst conjugate acid (reaction 4), the alkaline catalyst is regenerated to repeat reaction one.

[0035] Reaction three:

[0036] Reaction 4:

[0037] It should be noted that although alkenes, alkynes and isocyanates can all undergo click chemistry reactions with thiol groups, in the present invention, if alkenes, alkynes or isocyanates are used instead of epoxy groups to undergo click chemistry reactions with thiol groups, the same effect as that of epoxy groups cannot be achieved. The reason is that:

[0038] First, the reaction mechanism of thiol with olefins or alkynes is mainly free radical reaction, and the reaction usually requires the addition of initiators or light radiation, and the reaction temperature is usually high. In the silicon oxide system, the addition of initiators will affect the double electric layer on the silicon oxide surface, and the use of light radiation will introduce a large amount of energy, which will cause the system to be unstable, thereby causing the silicon oxide particles to agglomerate together, resulting in the appearance of a large number of irregularly shaped precipitates and the inability to obtain microspheres of relatively uniform size.

[0039] Secondly, the reaction mechanism of thiol with olefins or alkynes is that the thiol first forms a thiol radical, which then undergoes an addition reaction with an electron-rich unsaturated bond. This reaction, while initiating the formation of free radicals by the thiol, needs to suppress the formation of free radicals by the unsaturated bond, so the reaction conditions are relatively demanding.

[0040] The reaction mechanism of thiol and epoxy is a nucleophilic reaction. Due to the high activity of epoxy, the ring can be opened quickly under alkaline conditions. Therefore, it can usually be carried out under mild conditions. The alkaline catalyst used will not cause system instability and may even release OH. - , and can also increase the absolute value of the zeta potential of silicon oxide, making the system more stable.

[0041] In addition, free radical reactions are prone to produce side reactions and generate different adducts. If mercapto groups are used to react with alkenes or alkynes, the particle size will be very uneven. However, the present application uses mercapto groups and epoxy groups to react, which is relatively pure, has basically no by-products, and has a very high reaction selectivity, which is conducive to obtaining microspheres with uniform particle size.

[0042] Isocyanate compounds are usually toxic and irritating. In addition, isocyanate groups are easily hydrolyzed into amine groups in water systems and are easily inactivated before the click reaction, resulting in a decrease in the efficiency of the click reaction.

[0043] Therefore, the present invention selects thiol and epoxy groups to carry out click chemistry reaction, which can not only control the self-assembly process and results, but also has the advantages of mild reaction conditions, no by-products, fast reaction rate, low toxicity, etc.

[0044] Since the process of forming large-sized particles through self-assembly of small-sized silicon oxide particles is affected by multiple factors, among which steric effect is one of the important limiting factors, if the particle size of the small-sized silicon oxide particles is too large, only submicron-sized silicon oxide particles can be formed due to steric hindrance. Therefore, in the present invention, the particle sizes of the first silicon oxide particles and the second silicon oxide particles are independently less than or equal to 100 nm, preferably 20 nm-100 nm.

[0045] In addition, the particle sizes of the first silicon oxide particles and the second silicon oxide particles differ by less than 30 nm. This is because, if the particle sizes of the first silicon oxide particles and the second silicon oxide particles differ too much, when the first silicon oxide particles and the second silicon oxide particles are assembled layer by layer, the small-sized silicon oxide particles will adhere to the large-sized silicon oxide particles, and micron-sized silicon oxide particles cannot be obtained.

[0046] Furthermore, the smaller the difference in particle size between the first silicon oxide particles and the second silicon oxide particles is, the better the effect of layer-by-layer phase assembly of the first silicon oxide particles and the second silicon oxide particles is. Therefore, preferably, the particle size difference between the first silicon oxide particles and the second silicon oxide particles is within 20 nm, more preferably within 10 nm, and more preferably the particle sizes are equal.

[0047] It should be noted that when the particle sizes of the first silicon oxide particles and the second silicon oxide particles are not equal, the particle size of the first silicon oxide particles can be larger than the particle size of the second silicon oxide particles, or the particle size of the second silicon oxide particles can be larger than the particle size of the first silicon oxide particles, and there is no special requirement between the two.

[0048] Furthermore, the particle sizes of the first silicon oxide particles and the second silicon oxide particles are independently selected from 20nm-60nm, including but not limited to 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, etc., and the particle size of the obtained micron-sized silicon oxide particles is between 1μm and 2μm, and the specific surface area reaches 360m 2 / g or so.

[0049] In order to ensure that the epoxy groups can react completely during the click chemistry reaction, when the silicon oxide particles containing thiol groups on the surface, the silicon oxide particles containing epoxy groups on the surface and the alkaline catalyst are mixed, the amounts of the silicon oxide particles containing thiol groups on the surface and the silicon oxide particles containing epoxy groups on the surface are based on the molar ratio of thiol groups to epoxy groups. The molar amount of thiol groups is preferably higher than the molar amount of epoxy groups. It is further preferred that the molar ratio of thiol groups to epoxy groups is 1.5:1-1:1, including but not limited to 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.

[0050] When performing click chemistry reaction, the reaction rate of thiol and epoxy groups is related to the alkalinity of the alkaline catalyst. In order to increase the reaction rate and shorten the growth cycle, the alkaline catalyst is preferably selected from LiOH, K 2 CO 3 , KOH, and tetrabutylammonium fluoride.

[0051] Furthermore, the temperature of the click chemistry reaction is preferably 80° C.-95° C., and the time is preferably 2 h-4 h.

[0052] The present invention does not specifically limit the methods of grafting mercapto groups on the first silicon oxide particles and grafting epoxy groups on the second silicon oxide particles, wherein both the mercapto group-containing silane coupling agent and the epoxy group-containing silane coupling agent can achieve the purpose of surface grafting through the condensation of the hydroxyl groups of the hydrolyzate with the hydroxyl groups on the surface of the silicon oxide particles.

[0053] Therefore, the present invention preferably uses a mercapto-containing silane coupling agent to graft mercapto groups on the first silicon oxide particles, wherein the mercapto-containing silane coupling agent is selected from at least one of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane; preferably uses an epoxy-containing silane coupling agent to graft epoxy groups on the second silicon oxide particles, wherein the epoxy-containing silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldiethoxysilane, and γ-glycidoxypropylchlorosilane.

[0054] Taking the grafting and click chemistry reactions of a mercapto-containing silane coupling agent and an epoxy-containing silane coupling agent as examples, the method for preparing micron-sized silicon oxide particles provided by the present invention specifically includes:

[0055] A first alcohol aqueous solution is prepared, a first weak base and the first silicon oxide particles are added to the first alcohol aqueous solution to obtain a first mixture, and then a mercapto-containing silane coupling agent is added to the first mixture for reaction, and a first reaction product is obtained after the reaction is completed, wherein the first reaction product includes silicon oxide particles having mercapto groups on the surface; wherein the mass ratio of water to alcohol in the first alcohol aqueous solution is 1:1-1:4, the alcohol is selected from at least one of methanol, ethanol, propanol, n-butanol, isopropanol, and amyl alcohol, the first weak base is selected from ammonia water, triethylamine, sodium bicarbonate, etc., the pH is preferably 8-10, and the mass fraction of the first weak base in the first mixture is preferably 10%-20%, the mass fraction of the first silicon oxide particles in the first mixture is preferably 3%-10%, the amount of the mercapto-containing silane coupling agent is 0.05%-1% of the mass of the first mixture, more preferably 0.2%-0.8%, the reaction temperature is preferably 20°C-80°C, more preferably 60°C-80°C, and the reaction time is preferably 1h-4h.

[0056] A second alcohol aqueous solution is prepared, a second weak base and the second nanometer-sized silicon oxide particles are added to the second alcohol aqueous solution to obtain a second mixture, and then an epoxy-containing silane coupling agent is added to the second mixture for reaction, and a second reaction product is obtained after the reaction is completed, wherein the second reaction product includes silicon oxide particles having epoxy groups on the surface; wherein the mass ratio of water to alcohol in the second alcohol aqueous solution is 1:1-1:4, the alcohol is selected from at least one of methanol, ethanol, propanol, n-butanol, isopropanol, and amyl alcohol, and the second weak base is selected from ammonia water, triethylamine , tetrabutylammonium hydroxide, etc., the pH is preferably 8-9.5, and the mass fraction of the second weak base in the second mixture is preferably 5%-10% to avoid premature ring opening of the epoxy group, the mass fraction of the second silicon oxide particles in the second mixture is preferably 3%-10%, the amount of the epoxy-containing silane coupling agent is based on the amount of the mercapto-containing silane coupling agent in the first mixture, and is added in a ratio of 1.5:1-1:1 to the molar ratio of mercapto to epoxy, the reaction temperature is preferably 25°C-70°C, and the reaction time is preferably 1h-4h.

[0057] Then, the first reaction product, the second reaction product and the alkaline catalyst are mixed and subjected to a click chemistry reaction to obtain micron-sized silicon oxide particles, wherein the amount of the alkaline catalyst used is 20%-100% of the total mass of the first silicon oxide particles and the second silicon oxide particles.

[0058] The present invention also provides a micron-sized silicon oxide particle obtained by the preparation method. Since the micron-sized silicon oxide particle of the present invention is obtained by layer-by-layer bulk phase assembly of silicon oxide particles with small particle sizes at the nanometer level, its surface is rough and its specific surface area is large; for example, the micron-sized silicon oxide particle with a particle size of 1 μm-2 μm obtained by layer-by-layer bulk phase assembly of first silicon oxide particles with a particle size of 20nm-60nm and second silicon oxide particles can reach a specific surface area of ​​360m 2 / g, while the silica particles with a particle size of 1μm-2μm prepared directly using methyltrimethoxysilane have a specific surface area of ​​only 3m 2 / g or so.

[0059] In addition, the surface of the micron-sized silica microspheres obtained by the present invention still retains the mercapto groups that have not participated in the reaction, and even retains the alkyl groups obtained by ring-opening of the epoxy groups, which can be used for further modification or functionalization.

[0060] The micron-sized silicon oxide particles obtained by the present invention can be widely used in various fields due to their unique size, structure and performance, such as:

[0061] In the medical field, it can be used as an efficient drug carrier. By loading drugs on its surface or inside, it can significantly improve the stability and bioavailability of drugs. In addition, it can also be used to develop long-acting sustained-release drugs to reduce the frequency of administration, thereby enhancing patients' treatment compliance. Moreover, micron-sized silica particles with surface functionalization, such as magnetic particles and multi-color fluorescent coded particles, can be widely used in immunoassays to achieve high-throughput detection of multiple samples or targets, and assist in the rapid diagnosis of diseases.

[0062] In the flat panel display industry, with its excellent optical properties, it can be used as a spacer to support the two layers of glass panels of the LCD screen, ensuring that the liquid crystal molecules have enough space to move and exert their due display effects.

[0063] In addition to the above applications, the micron-sized silicon oxide particles of the present invention can also be applied to multiple fields such as microelectronic packaging materials, potting materials, electronic circuit board fillers, silicone rubber, electronic ceramics, medical dental materials, cosmetics, electronic inks, new adhesives and sealants, etc., which are not described in detail in the present invention.

[0064] Hereinafter, the micron-sized silicon oxide particles and the preparation method thereof will be further described through the following specific examples.

[0065] Example 1

[0066] Mix 25 g of first silicon oxide particles with a particle size of 20 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 65°C, and then 2.40 g of 3-mercaptopropyltrimethoxysilane (MPTMS) is added, and the reaction is carried out for 2 hours to obtain a first reaction product.

[0067] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto to epoxy group is 1.2:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0068] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 50 g of potassium carbonate was added, and the reaction was carried out for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 352 m 2 / g.

[0069] Example 2

[0070] Mix 25 g of the first silicon oxide particles with a particle size of 20 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring at a stirring speed of 500 rpm, heat the water bath to 65° C., then add 2.40 g of MPTMS, react for 2 hours, and obtain a first reaction product.

[0071] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring at a speed of 500 rpm, heat the water bath to 60°C, then add 2.41 g of GPTMS (the molar ratio of thiol to epoxy group is 1.2:1), react for 2 hours, and obtain a second reaction product.

[0072] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 80°C, 10 g of LiOH was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 360 m 2 / g.

[0073] Example 3

[0074] Mix 25 g of the first silicon oxide particles with a particle size of 20 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring at a stirring speed of 500 rpm, heat the water bath to 65° C., then add 2.40 g of MPTMS, react for 2 hours, and obtain a first reaction product.

[0075] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring at a speed of 500 rpm, heat the water bath to 60°C, then add 2.41 g of GPTMS (the molar ratio of thiol to epoxy group is 1.2:1), react for 2 hours, and obtain a second reaction product.

[0076] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 85°C, 10 g of KOH was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 365 m 2 / g.

[0077] Example 4

[0078] Mix 25 g of the first silicon oxide particles with a particle size of 20 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring at a stirring speed of 500 rpm, heat the water bath to 65° C., then add 2.40 g of MPTMS, react for 2 hours, and obtain a first reaction product.

[0079] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring at a speed of 500 rpm, heat the water bath to 60°C, then add 2.41 g of GPTMS (the molar ratio of thiol to epoxy group is 1.2:1), react for 2 hours, and obtain a second reaction product.

[0080] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 15 g of tetrabutylammonium fluoride (TBAF) was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 356 m 2 / g.

[0081] Example 5

[0082] Mix 25 g of first silicon oxide particles with a particle size of 30 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring at a stirring speed of 500 rpm, heat the water bath to 65°C, then add 2.00 g of 3-mercaptopropyltrimethoxysilane (MPTMS), react for 2 hours, and obtain a first reaction product.

[0083] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto and epoxy groups is 1:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0084] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 80°C, 10 g of LiOH was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 364 m 2 / g.

[0085] Example 6

[0086] Mix 25 g of first silicon oxide particles with a particle size of 40 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 65°C, and then 2.60 g of 3-mercaptopropyltrimethoxysilane (MPTMS) is added, and the reaction is carried out for 2 hours to obtain a first reaction product.

[0087] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto to epoxy group is 1.3:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0088] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 10 g of LiOH was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 358 m 2 / g.

[0089] Example 7

[0090] Mix 25 g of the first silicon oxide particles with a particle size of 60 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 65°C, and then 2.80 g of 3-mercaptopropyltrimethoxysilane (MPTMS) is added, and the reaction is carried out for 2 hours to obtain a first reaction product.

[0091] Mix 25 g of the second silicon oxide particles with a particle size of 60 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto and epoxy groups is 1.4:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0092] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 10 g of LiOH was added, and the reaction was continued for 4 hours to obtain micron-sized silicon oxide particles. After testing, the particle size of the micron-sized silicon oxide particles was 1 μm-2 μm, and the specific surface area was 347 m 2 / g.

[0093] Comparative Example 1

[0094] Mix 25 g of the first silicon oxide particles with a particle size of 20 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring at a stirring speed of 500 rpm, heat the water bath to 65° C., then add 2.40 g of MPTMS, react for 2 hours, and obtain a first reaction product.

[0095] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring at a speed of 500 rpm, heat the water bath to 60°C, then add 2.41 g of GPTMS (the molar ratio of thiol to epoxy group is 1.2:1), react for 2 hours, and obtain a second reaction product.

[0096] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, and the reaction was carried out for 4 hours. Figure 2 As shown, the silicon oxide particles are still small in size of about 20 nm, and no micron-sized silicon oxide particles appear.

[0097] Comparative Example 2

[0098] Mix 25 g of first silicon oxide particles with a particle size of 80 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 65°C, and then 2.80 g of 3-mercaptopropyltrimethoxysilane (MPTMS) is added, and the reaction is carried out for 2 hours to obtain a first reaction product.

[0099] Mix 25 g of the second silicon oxide particles with a particle size of 20 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto and epoxy groups is 1.4:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0100] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 10 g of LiOH was added, and the reaction was continued for 4 hours. After testing, the product was large-sized silicon oxide particles adsorbed with small-sized silicon oxide particles, and no micron-sized silicon oxide particles were obtained. The specific surface area was 152 m 2 / g.

[0101] Comparative Example 3

[0102] Mix 25 g of the first silicon oxide particles with a particle size of 120 nm, 50 g of ammonia water, 141.67 g of deionized water, and 283.33 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 65°C, and then 3.00 g of 3-mercaptopropyltrimethoxysilane (MPTMS) is added, and the reaction is carried out for 2 hours to obtain a first reaction product.

[0103] Mix 25 g of the second silicon oxide particles with a particle size of 120 nm, 25 g of ammonia water, 150 g of deionized water, and 300 g of ethanol, start mechanical stirring, the stirring speed is 500 rpm, the water bath is heated to 60°C, and then 2.41 g (the molar ratio of mercapto to epoxy group is 1.5:1) of γ-glycidyloxypropyltrimethoxysilane (GPTMS) is added, and the reaction is carried out for 2 hours to obtain a second reaction product.

[0104] The first reaction product and the second reaction product were mixed, the speed was adjusted to 200 rpm, the temperature was raised to 90°C, 10 g of LiOH was added, and the reaction was carried out for 4 hours to obtain micron-sized silicon oxide particles. After testing, the product was large-sized silicon oxide particles adsorbed with small-sized silicon oxide particles, and no micron-sized silicon oxide particles were obtained. The specific surface area was 103 m 2 / g.

[0105] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing micron-sized silicon oxide particles, characterized in that: The following steps are involved: Grafting mercapto groups on first silicon oxide particles to obtain silicon oxide particles having mercapto groups on the surface, and grafting epoxy groups on second silicon oxide particles to obtain silicon oxide particles having epoxy groups on the surface, wherein the particle sizes of the first silicon oxide particles and the second silicon oxide particles are both less than or equal to 100 nm, and the particle sizes of the first silicon oxide particles and the second silicon oxide particles differ by less than 30 nm; The silicon oxide particles containing mercapto groups on the surface, the silicon oxide particles containing epoxy groups on the surface and an alkaline catalyst are mixed and subjected to a click chemical reaction to obtain micron-sized silicon oxide particles.

2. The method for preparing micron-sized silicon oxide particles according to claim 1, characterized in that: The first silicon oxide particles and the second silicon oxide particles satisfy at least one of the following relationships: (1) The particle sizes of the first silicon oxide particles and the second silicon oxide particles differ by less than 20 nm; (2) The particle sizes of the first silicon oxide particles and the second silicon oxide particles are independently selected from 20 nm to 60 nm.

3. The method for preparing micron-sized silicon oxide particles according to claim 1 or 2, characterized in that: A mercapto group is grafted onto the first silicon oxide particles using a mercapto group-containing silane coupling agent.

4. The method for preparing micron-sized silicon oxide particles according to claim 3, characterized in that: The mercapto-containing silane coupling agent is selected from at least one of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

5. The method for preparing micron-sized silicon oxide particles according to claim 1 or 2, characterized in that: An epoxy group is grafted onto the second silicon oxide particles by using an epoxy group-containing silane coupling agent.

6. The method for preparing micron-sized silicon oxide particles according to claim 5, characterized in that: The epoxy-containing silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyldiethoxysilane and γ-glycidoxypropylchlorosilane.

7. The method for preparing micron-sized silicon oxide particles according to claim 1 or 2, characterized in that: The step of mixing the silicon oxide particles having mercapto groups on the surface, the silicon oxide particles having epoxy groups on the surface, and the alkaline catalyst satisfies at least one of the following conditions: (1) The amount of the silicon oxide particles containing mercapto groups on the surface and the silicon oxide particles containing epoxy groups on the surface is based on the molar ratio of mercapto groups to epoxy groups, wherein the molar ratio of mercapto groups to epoxy groups is 1.5:1-1:1; (2) The alkaline catalyst is selected from at least one of LiOH, K2CO3, KOH, and tetrabutylammonium fluoride.

8. The method for preparing micron-sized silicon oxide particles according to claim 1 or 2, characterized in that: The temperature of the click chemistry reaction is 80° C.-95° C., and the reaction time is 2 h-4 h.

9. Micron-sized silicon oxide particles obtained by the preparation method according to any one of claims 1 to 8.

10. The micron-sized silicon oxide particles according to claim 9, characterized in that: The particle size of the micron-sized silicon oxide particles is 1 μm-2 μm.

Images