A method for preparing a dispersion of nanosilica

Abstract

This invention discloses a method for preparing dispersed nano-silica. The method includes the following steps: (1) heating industrial-grade polyisobutylene succinic anhydride to 140-180°C, stirring and adding raw materials, reacting for 4-8 hours to obtain a polymeric surfactant, designated as product A; the raw materials are alcohols, amines, or alkanolamines with different hydrophilic groups; (2) adding base oil, ammonia, and deionized water to product A, stirring, then adding tetraethyl orthosilicate, reacting to obtain a suspension, subjecting the suspension to a hydrothermal reaction to obtain a crystallized solution, designated as product B; (3) adding ethyl acetate and anhydrous ethanol to product B, ultrasonicating, centrifuging, drying, and calcining to obtain nano-silica. This invention features readily available and inexpensive raw materials, a simple preparation method, small particle size of the prepared silica, good dispersion effect, and good industrialization potential.

Description

Technical Field

[0001] This invention relates to a method for preparing silica, and more particularly to a method for preparing dispersed nano-silica. Background Technology

[0002] Nano-silica possesses advantages such as low density, large specific surface area, good biocompatibility, and good colloidal stability, thus it is widely used in catalysis, microelectronics, optical systems, and biomedicine. Therefore, the large-scale preparation of dispersed nano-silica particles is of great significance to these fields. Many research groups have prepared nano-silica using hydrothermal methods, sol-gel methods, precipitation methods, electrospinning methods, and chemical vapor deposition methods. Since 1968... Since Fink and Bohn pioneered the preparation of micron-sized spherical silica under surfactant-free conditions, extensive research and exploration have been conducted. Silica nanoparticles can be prepared by conventional methods or other means. However, these methods often involve the use of toxic reagents, significantly increased costs, or are cumbersome, with long reaction times and high temperatures, making it difficult to control the particle size and morphology of the prepared nano-silica. In contrast, microemulsion methods produce nano-silica with uniform particle size and morphology, and offer greater control over the particle size and morphology. However, microemulsion methods are affected by solvents and surfactants; the interfacial interactions between these substances significantly reduce the reproducibility of nano-silica preparations.

[0003] Therefore, synthesizing nano-silica materials with small particle size has great scientific significance, but it is also a huge challenge. This invention provides a method for preparing dispersed nano-silica. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing dispersed nano-silica. This invention features readily available and inexpensive raw materials, a simple preparation method, and produces silica with small particle size and good dispersion, thus possessing excellent industrialization potential.

[0005] The technical solution of this invention: a method for preparing dispersed nano-silica, comprising the following steps:

[0006] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw materials are alcohols, amines or alkanolamines with different hydrophilic groups;

[0007] (2) Add base oil, ammonia and deionized water to product A, stir, then add tetraethyl orthosilicate, react to obtain a suspension, and carry out a hydrothermal reaction of the suspension to obtain a crystallized solution, which is product B.

[0008] (3) Add ethyl acetate and anhydrous ethanol to product B, sonicate, centrifuge, dry, and calcine to obtain nano-silica.

[0009] In the aforementioned method for preparing dispersed nano-silica, in step (1), the molar ratio of industrial-grade polymeric polyisobutylene succinic anhydride to the raw material is 1:0.5-2.

[0010] In the aforementioned method for preparing dispersed nano-silica, in step (1), the molar ratio of industrial-grade polymeric polyisobutylene succinic anhydride to the raw material is 1:1.5-2.

[0011] In the aforementioned method for preparing dispersed nano-silica, in step (1), the molar ratio of industrial-grade polymeric polyisobutylene succinic anhydride to the raw material is 1:2.

[0012] In the aforementioned method for preparing dispersed nano-silica, in step (1), the alcohols with different hydrophilic groups are ethylene glycol, diethylene glycol, or triethylene glycol; the amines are urea, diethylenetriamine, or triethylenetetramine; and the alcohol amines are N,N-dimethylethanolamine, 2-methylaminoethanol, or triethanolamine.

[0013] In the aforementioned method for preparing dispersed nano-silica, the raw material is an amine.

[0014] In the aforementioned method for preparing dispersed nano-silica, the amine is diethylenetriamine.

[0015] In the aforementioned method for preparing dispersed nano-silica, in step (2), 18-22g of base oil, 3-4mL of ammonia and 72-88mL of deionized water are added to 1g of product A. The concentration of ammonia is 0.02-0.06mol / L. The mixture is stirred for 0.5-1h, and then 6.5-7.5mL of tetraethyl orthosilicate is added. The mixture is reacted for 3-4h to obtain a suspension. The suspension is subjected to a hydrothermal reaction at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B.

[0016] In the aforementioned method for preparing dispersed nano-silica, 20g of base oil, 4mL of ammonia water, and 80mL of deionized water are added to 1g of product A. The concentration of ammonia water is 0.04mol / L. The mixture is stirred for 1h, and then 7.2mL of tetraethyl orthosilicate is added. The mixture is reacted for 3.5h to obtain a suspension. The suspension is then subjected to a hydrothermal reaction at 100℃ for 24h to obtain a crystallized solution, which is product B.

[0017] In the aforementioned method for preparing dispersed nano-silica, in step (3), 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol are added to 5 mL of product B, followed by sonication, centrifugation, drying at 70-90℃ for 2-4 h, and calcination at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0018] In the aforementioned method for preparing dispersed nano-silica, the base oil is base oil SN150.

[0019] In the aforementioned method for preparing dispersed nano-silica, in step (3), 10 mL of ethyl acetate and 10 mL of anhydrous ethanol are added to 5 mL of product B, followed by sonication, centrifugation, drying at 80°C for 3 h, and calcination at 550°C for 6 h at a heating rate of 5°C / min to obtain nano-silica.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention involves heating industrial-grade polyisobutylene succinic anhydride to 140-180℃ to keep it in a fluid state, thus ensuring a more complete subsequent reaction. Raw materials are added with stirring, and at high temperature, the industrial-grade polyisobutylene succinic anhydride undergoes a ring-opening reaction, dehydrating with the hydroxyl groups of corresponding alcohol raw materials to form alcohol ester products, dehydrating with amine raw materials to form amide products, or dehydrating with corresponding alkanolamine raw materials to form amino-containing alcohol ester products. The reaction proceeds for 4-8 hours to obtain the corresponding polymeric surfactant, grade A. The raw materials are alcohols, amines, or alkanolamines with different hydrophilic groups.

[0022] This invention involves adding base oil and ammonia to product A, stirring and dispersing, then adding tetraethyl orthosilicate. During stirring, hydrolysis generates a silica suspension. The silica suspension is then subjected to a hydrothermal crystallization reaction. No chemical reaction occurs during the crystallization process. To stabilize the morphology of spherical silica, crystallization is carried out for 20-28 hours to obtain a crystallized solution, product B. Specifically, product A is used as a dispersant. 18-22g of base oil, 3-4mL of ammonia, and 72-88mL of deionized water are added to 1g of product A. The concentration of ammonia is 0.02-0.06mol / L. The mixture is stirred for 0.5-1h, then 6.5-7.5mL of tetraethyl orthosilicate is added. The reaction is carried out for 3-4h to obtain a suspension. The suspension is then subjected to a hydrothermal reaction at 90-110℃ for 20-28h to obtain a crystallized solution, product B.

[0023] This invention involves adding ethyl acetate and anhydrous ethanol to product B, followed by sonication. The addition of ethyl acetate and anhydrous ethanol is for demulsification, allowing silica to separate. Then, the product is centrifuged, dried, and calcined to obtain nano-silica. Drying effectively removes free water, while calcination removes bound water that cannot be dried.

[0024] All the raw materials used in the operation of this invention can be obtained through simple channels, and industrial-grade materials are inexpensive and readily available.

[0025] In the experimental demonstration section: Examples 1-9 of this invention show that polyisobutylene succinic anhydride-based polymeric surfactants can be used as dispersants to prepare nano-silica with a diameter of about 10 nm, indicating that polyisobutylene succinic anhydride-based polymeric surfactants have universality when used as dispersants to prepare nano-silica.

[0026] Comparing Examples 1-9, in Example 5, when the molar ratio of polyisobutylene succinic anhydride to diethylenetriamine was 1:2, the prepared silica had a clear morphology, with visible dispersed spherical silica particles, no obvious agglomeration, and good dispersion. The silica particle size distribution ranged from 5-15 nm, with a concentration in the 8-10 nm range. Therefore, this invention uses a molar ratio of polyisobutylene succinic anhydride to diethylenetriamine of 1:2 as the basis for Examples 10-12.

[0027] Example 10 shows that when the ratio of base oil to deionized water is 2:8, the prepared nano-silica has a better dispersion effect, with a particle size distribution range of 4-16nm and concentrated dispersion in 8-10nm.

[0028] Example 11 shows that, corresponding Figure 12 AD, changing the concentration of tetraethyl orthosilicate does not affect the morphology of silica, but it can significantly improve the aggregation of nano-silica particles, allowing them to form dispersed nano-silica particles. Therefore, the optimal concentration of tetraethyl orthosilicate is 7.2 mL.

[0029] Example 12 shows that changing the ammonia concentration does not affect the morphology and particle size of silica. Figure 13 AD, however, can significantly improve the aggregation of nano-silica particles, enabling them to form monodisperse nano-silica particles. Considering the effect of the yield, the optimal ammonia concentration was determined to be 4 mL.

[0030] In summary, the present invention has the advantages of using inexpensive and readily available raw materials, a simple preparation method, producing silica with small particle size and good dispersion, and possessing good industrialization potential. Attached Figure Description

[0031] Figure 1 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-ethylene glycol at different molar ratios according to the present invention; wherein... Figure 1 The molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:0.5. Figure 1The molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:1. Figure 1 The molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:2;

[0032] Figure 2 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-diethylene glycol at different molar ratios according to the present invention; wherein... Figure 2 The molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:0.5. Figure 2 The molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:1. Figure 2 The molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:2;

[0033] Figure 3 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-triethylene glycol at different molar ratios according to the present invention; wherein... Figure 3 The molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:0.5. Figure 3 The molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:1. Figure 3 The molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:2;

[0034] Figure 4 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-urea at different molar ratios according to the present invention; wherein... Figure 4 The molar ratio of polyisobutylene succinic anhydride to urea is 1:0.5. Figure 4 The molar ratio of polyisobutylene succinic anhydride to urea is 1:1. Figure 4 The molar ratio of polyisobutylene succinic anhydride to urea is 1:2;

[0035] Figure 5 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-diethylenetriamine in different molar ratios according to the present invention; wherein Figure 5 The molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:0.5. Figure 5 The molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:1. Figure 5 The molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:2;

[0036] Figure 6 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-triethylenetriamine in different molar ratios according to the present invention; wherein... Figure 6 The molar ratio of polyisobutylene succinic anhydride to triethylenetriamine is 1:0.5. Figure 6 The molar ratio of polyisobutylene succinic anhydride to triethylenetriamine is 1:1. Figure 6 The molar ratio of polyisobutylene succinic anhydride to triethylenetriamine is 1:2;

[0037] Figure 7 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-N,N-dimethylethanolamine in different molar ratios according to the present invention; wherein... Figure 7 The molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:0.5. Figure 7 The molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:1. Figure 7 The molar ratio of C-polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:2;

[0038] Figure 8 These are SEM images of nano-silica prepared from polyisobutylene succinic anhydride-2-methylaminoethanol at different molar ratios according to this invention; wherein... Figure 8 The molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:0.5. Figure 8 The molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:1. Figure 8 The molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:2;

[0039] Figure 9 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-triethanolamine at different molar ratios according to the present invention; wherein Figure 9 The molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:0.5. Figure 9 The molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:1. Figure 9 The molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:2;

[0040] Figure 10 These are SEM images of nano-silica prepared by different oil-water ratios of polyisobutylene succinic anhydride-diethylenetriamine with a molar ratio of 1:2 according to the present invention; wherein Figure 10 The ratio of base oil to deionized water in A is 1:9. Figure 10 The ratio of base oil to deionized water in B is 2:8; Figure 10 The ratio of base oil to deionized water in C is 3:7; Figure 10 The ratio of base oil to deionized water in D is 4:6; Figure 10 The ratio of base oil to deionized water in E is 5:5;

[0041] Figure 11 These are TEM images of nano-silica prepared by different oil-water ratios of polyisobutylene succinic anhydride-diethylenetriamine with a molar ratio of 1:2 according to the present invention; wherein Figure 11 The ratio of base oil to deionized water in A is 1:9. Figure 11 The ratio of base oil to deionized water in B is 2:9; Figure 11 The ratio of base oil to deionized water in C is 3:7; Figure 11 The ratio of base oil to deionized water in D is 4:6; Figure 11 The ratio of base oil to deionized water in E is 5:5;

[0042] Figure 12 These are SEM images of nano-silica prepared by polyisobutylene succinic anhydride-diethylenetriamine in a molar ratio of 1:2 with different tetraethyl orthosilicate concentrations according to the present invention; wherein Figure 12 A is a SEM image of the nano-silica prepared by adding 3.6 mL of tetraethyl orthosilicate. Figure 12 SEM image of nano-silica prepared by adding 7.2 mL of tetraethyl orthosilicate to B. Figure 12 C is a SEM image of the nano-silica prepared by adding 10.8 mL of tetraethyl orthosilicate. Figure 12 D is a SEM image of the nano-silica prepared by adding 14.0 mL of tetraethyl orthosilicate.

[0043] Figure 13 This is a SEM image of nano-silica prepared by polyisobutylene succinic anhydride-diethylenetriamine with a molar ratio of 1:2 according to the present invention at different ammonia concentrations. Figure 13 A is a SEM image of nano-silica prepared when the ammonia concentration is 0.02 mol / L. Figure 13 B is a SEM image of the nano-silica prepared when the ammonia concentration is 0.04 mol / L. Figure 13 C is a SEM image of the nano-silica prepared when the ammonia concentration is 0.06 mol / L. Figure 13 D is a SEM image of nano-silica prepared when the ammonia concentration is 0.08 mol / L. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0045] Example 1. A method for preparing dispersed nano-silica, comprising the following steps:

[0046] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is ethylene glycol; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0047] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0048] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0049] Example 2. A method for preparing dispersed nano-silica, comprising the following steps:

[0050] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is diethylene glycol; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0051] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0052] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0053] Example 3. A method for preparing dispersed nano-silica, comprising the following steps:

[0054] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is triethylene glycol; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0055] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0056] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0057] Example 4. A method for preparing dispersed nano-silica, comprising the following steps:

[0058] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is urea; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0059] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0060] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0061] Example 5. A method for preparing dispersed nano-silica, comprising the following steps:

[0062] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is diethylenetriamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0063] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0064] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0065] Example 6. A method for preparing dispersed nano-silica, comprising the following steps:

[0066] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is triethylenetetramine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0067] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0068] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0069] Example 7. A method for preparing dispersed nano-silica, comprising the following steps:

[0070] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw material, react for 4-8h to obtain high molecular surfactant, which is grade A; the raw material is N,N-dimethylethanolamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw material is 1:0.5 / 1:1 / 1:2.

[0071] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0072] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0073] Example 8. A method for preparing dispersed nano-silica, comprising the following steps:

[0074] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is 2-methylaminoethanol; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0075] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0076] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0077] Example 9. A method for preparing dispersed nano-silica, comprising the following steps:

[0078] (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180℃, stir and add raw materials, react for 4-8 hours to obtain a high molecular surfactant, which is grade A; the raw material is triethanolamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw materials is 1:0.5 / 1:1 / 1:2.

[0079] (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0080] (3) Add 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 70-90℃ for 2-4 h, and calcine at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

[0081] Experiments have shown that:

[0082] Examples 1-3 are polymeric surfactants prepared from polyisobutylene succinic anhydride and alcohols of different molecular weights.

[0083] Example 1 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-ethylene glycol in different molar ratios according to the present invention. Figure 1 SEM image of nano-silica, as shown Figure 1 The particle size shown in AC is concentrated in the range of 8-20 nm; among which... Figure 1 The molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:0.5. The particle size distribution of silica ranges from 8 to 20 nm, with the silica particles concentrated in the 10-12 nm range. The morphology of the nano silica is unclear and agglomerated. Figure 1 The molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:1. The particle size distribution of silica ranges from 7 to 16 nm, with concentrated dispersion in the 10-12 nm range. The morphology of nano silica is unclear and agglomerated. Figure 1 When the molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:2, the particle size distribution of silica ranges from 7 to 16 nm, with a concentration in the 9-12 nm range. The spherical morphology of silica is clearly visible, and the agglomeration phenomenon is not obvious, indicating that the silica dispersion effect is good. Therefore, when the molar ratio of polyisobutylene succinic anhydride to ethylene glycol is 1:2, the prepared silica has a clear morphology, good dispersion effect, and no obvious agglomeration phenomenon, with a particle size distribution range of 7-16 nm and a concentration in the 9-12 nm range.

[0084] Example 2 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-diethylene glycol in different molar ratios according to the present invention. Figure 2 SEM image of nano-silica, as shown Figure 2 The particle size shown in AC is dispersed between 7-16 nm, where Figure 2The molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:0.5. The particle size distribution of silica ranges from 7 to 16 nm, with the silica particles concentrated in the 11-12 nm range. The silica morphology is unclear and agglomerated. Figure 2 The molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:1. The particle size distribution of silica ranges from 7 to 16 nm, with the silica particles concentrated in the 10-12 nm range. The silica morphology is unclear and agglomerated. Figure 2 When the molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:2, the particle size distribution of silica ranges from 7 to 16 nm, with the majority of silica particles concentrated in the 9-12 nm range. This indicates that the silica exhibits good morphology, minimal agglomeration, and good dispersion. Therefore, when the molar ratio of polyisobutylene succinic anhydride to diethylene glycol is 1:2, the prepared silica has a clear morphology, minimal agglomeration, good dispersion, and a particle size distribution range of 7-16 nm, with the majority of silica particles concentrated in the 9-12 nm range.

[0085] Example 3 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-triethylene glycol in different molar ratios according to the present invention. Figure 3 SEM image of nano-silica, as shown Figure 3 The particle size shown in AC is dispersed between 7-20 nm, where Figure 3 The molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:0.5. The particle size distribution of silica ranges from 8 to 20 nm, with the silica particles concentrated in the 10-12 nm range. The morphology of the nano silica is unclear, and the agglomeration phenomenon is obvious. Figure 3 The molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:1. The particle size distribution of silica ranges from 7 to 16 nm, with the silica particles concentrated in the 10-12 nm range. The silica morphology is unclear and agglomerated. Figure 3 When the molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:2, the silica particles have a size distribution range of 7-16 nm, concentrated in the 10-12 nm range. The nano-silica has a clear morphology and no obvious agglomeration, resulting in good dispersion. Therefore, when the molar ratio of polyisobutylene succinic anhydride to triethylene glycol is 1:2, the prepared silica has a clear morphology and good dispersion, with no obvious agglomeration, a particle size distribution range of 7-16 nm, and concentrated in the 10-12 nm range.

[0086] Examples 4-6 are polymeric surfactants prepared from polyisobutylene succinic anhydride and amines of different molecular weights.

[0087] Example 4 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-urea in different molar ratios according to the present invention. Figure 4 SEM image of nano-silica, as shown Figure 4 The particle size shown in AC is dispersed between 8-15 nm, where Figure 4The molar ratio of polyisobutylene succinic anhydride to urea is 1:0.5. The particle size distribution of silica ranges from 8 to 15 nm, with the silica particles concentrated in the range of 9 to 12 nm. The morphology of the nano silica is unclear, and there is a serious agglomeration phenomenon. Figure 4 The molar ratio of polyisobutylene succinic anhydride to urea is 1:1. The particle size distribution of silica ranges from 6 to 14 nm, with the silica particles concentrated in the 10-12 nm range. The morphology of the nano silica is still not clear enough and it is agglomerated. Figure 4 When the molar ratio of polyisobutylene succinic anhydride to urea is 1:2, the silica particle size distribution ranges from 6 to 14 nm, with a concentration in the 9-12 nm range. The nano-silica exhibits a clear morphology, minimal agglomeration, and good dispersibility. Therefore, when the molar ratio of polyisobutylene succinic anhydride to urea is 1:2, the prepared silica has a clear morphology, minimal agglomeration, good dispersibility, and a particle size distribution range of 6-14 nm, with a concentration in the 9-12 nm range.

[0088] Example 5 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-diethylenetriamine in different molar ratios according to the present invention. Figure 5 SEM image of nano-silica, as shown Figure 5 The particle size shown in AC is dispersed between 5-20 nm, among which Figure 5 The molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:0.5. The particle size distribution of silica ranges from 8 to 20 nm, with the concentration concentrated in the 10-12 nm range. It can be seen that the nano silica is severely agglomerated into sheet-like silica. Figure 5 The molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:1. The particle size distribution of silica ranges from 9 to 19 nm, with the silica particles concentrated in the 10-12 nm range. It can also be seen that the silica is lamellar due to agglomeration. Figure 5 When the molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:2, the silica particle size distribution ranges from 5 to 15 nm, with a concentration of 8 to 10 nm. The silica morphology is clear, with visible dispersed spherical silica particles and no obvious agglomeration, indicating good dispersion. Therefore, when the molar ratio of polyisobutylene succinic anhydride to diethylenetriamine is 1:2, the prepared silica has a clear morphology, with visible dispersed spherical silica particles and no obvious agglomeration, indicating good dispersion. The silica particle size distribution ranges from 5 to 15 nm, with a concentration of 8 to 10 nm.

[0089] Example 6 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-triethylenetetramine in different molar ratios according to the present invention. Figure 6 SEM image of nano-silica, as shown Figure 6 The particle size shown in AC is dispersed between 6-20 nm, among which Figure 6The molar ratio of polyisobutylene succinic anhydride to triethylenetetramine is 1:0.5. The particle size distribution of silica ranges from 6 to 20 nm, with the majority of silica particles concentrated in the 9-12 nm range. However, the morphology of nano-silica is irregular and the agglomeration phenomenon is severe. Figure 6 The molar ratio of polyisobutylene succinic anhydride to triethylenetetramine is 1:1. The particle size distribution of silica ranges from 6 to 19 nm, with the silica particles concentrated in the range of 9 to 11 nm. The morphology is obvious, but there is obvious agglomeration. Figure 6 When the molar ratio of polyisobutylene succinic anhydride to triethylenetetramine is 1:2, the particle size distribution of silica ranges from 6 to 19 nm, with a concentrated dispersion in the 9-11 nm range. The morphology is clear, the dispersion effect is good, and no obvious agglomeration into lumps is observed. Therefore, when the molar ratio of polyisobutylene succinic anhydride to triethylenetetramine is 1:2, the prepared silica has a particle size distribution range of 6-19 nm, with a concentrated dispersion in the 9-11 nm range. The morphology is clear, the dispersion effect is good, and no obvious agglomeration into lumps is observed.

[0090] Examples 7-9 are polymeric surfactants prepared from polyisobutylene succinic anhydride and alcohol amines.

[0091] Example 7 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-N,N-dimethylethanolamine in different molar ratios according to the present invention. Figure 7 SEM image of nano-silica, as shown Figure 7 The particle size shown in AC is dispersed between 5-19 nm, among which Figure 7 The molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:0.5. The particle size distribution of silica ranges from 5 to 15 nm, with the silica concentrated in the range of 8 to 10 nm, indicating severe agglomeration. Figure 7 The molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:1, and the particle size distribution of silica ranges from 9 to 19 nm, with the majority of silica particles concentrated in the 11-13 nm range. Figure 7 When the molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:2, the silica particle size distribution range is 9-19 nm, concentrated in the 9-11 nm range and well dispersed. Therefore, when the molar ratio of polyisobutylene succinic anhydride to N,N-dimethylethanolamine is 1:2, the prepared silica has a good dispersion effect, and the silica particle size distribution range is 9-19 nm, concentrated in the 9-11 nm range and well dispersed.

[0092] Example 8 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-2-methylaminoethanol at different molar ratios according to the present invention. Figure 8 SEM image of nano-silica, as shown Figure 8 The particle size shown in AC is dispersed between 6-18 nm, among which Figure 8The molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:0.5. The particle size distribution of silica ranges from 9 to 18 nm, with the silica particles concentrated in the 10-12 nm range. The morphology of the nano silica is unclear and it is severely agglomerated. Figure 8 The molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:1. The particle size distribution of silica ranges from 6 to 18 nm, with the silica particles concentrated in the 10-12 nm range. The nano-silica exhibits a clear morphological profile, but also shows obvious agglomeration. Figure 8 When the molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:2, the silica particle size distribution ranges from 9 to 18 nm, with a concentration in the 9-11 nm range. The spherical morphology of the silica is clearly visible, indicating good dispersion and minimal agglomeration. Therefore, when the molar ratio of polyisobutylene succinic anhydride to 2-methylaminoethanol is 1:2, the prepared silica exhibits a spherical morphology, good dispersion, minimal agglomeration, and a particle size distribution range of 9 to 18 nm, with a concentration in the 9-11 nm range.

[0093] Example 9 illustrates the preparation of nano-silica using polyisobutylene succinic anhydride-triethanolamine in different molar ratios according to the present invention. Figure 9 SEM image of silica, as shown Figure 9 The particle size distribution shown in AC ranges from 8 to 18 nm; where... Figure 2 The molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:0.5. The particle size distribution of silica ranges from 8 to 18 nm, with the silica particles concentrated in the 10-12 nm range. The morphology of the nano silica is unclear and it is severely agglomerated. Figure 9 The molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:1. The particle size distribution of silica ranges from 8 to 17 nm, with concentrated dispersion in the range of 9 to 11 nm. The morphology of nano silica is unclear and there is obvious agglomeration. Figure 9 When the molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:2, the particle size distribution of silica ranges from 6 to 19 nm, with a concentration in the 9-11 nm range. The silica exhibits a spherical morphology, good dispersion, and minimal agglomeration. Therefore, when the molar ratio of polyisobutylene succinic anhydride to triethanolamine is 1:2, the prepared silica exhibits a spherical morphology, good dispersion, minimal agglomeration, and a particle size distribution range of 6-19 nm, with a concentration in the 9-11 nm range.

[0094] Examples 1-9 show that polyisobutylene succinic anhydride-based polymeric surfactants can all be used as dispersants to prepare nano-silica with a diameter of about 10 nm, indicating that polyisobutylene succinic anhydride-based polymeric surfactants are universally applicable when used as dispersants to prepare nano-silica.

[0095] Comparing Examples 1-9, in Example 5, when the molar ratio of polyisobutylene succinic anhydride to diethylenetriamine was 1:2, the prepared silica had a clear morphology, with visible dispersed spherical silica particles, no obvious agglomeration, and good dispersion. The silica particle size distribution ranged from 5-15 nm, with a concentration in the 8-10 nm range. Therefore, this invention uses a molar ratio of polyisobutylene succinic anhydride to diethylenetriamine of 1:2 as the basis for Examples 10-12.

[0096] Example 10. A method for preparing dispersed nano-silica, comprising the following steps:

[0097] (1) Heat industrial grade polyisobutylene succinic anhydride to 160°C, stir and add raw material, react for 6 hours to obtain high molecular surfactant, which is grade A; the raw material is diethylenetriamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw material is 1:2.

[0098] (2) Add 20g of base oil, 4mL of ammonia water and 20-198mL of deionized water to 1g of product A. The concentration of ammonia water is 0.04mol / L. Stir for 1h, then add 0.072mL of tetraethyl orthosilicate. React for 3.5h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 100℃ for 24h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0099] (3) Add 10 mL of ethyl acetate and 10 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 80 °C for 3 h, and calcine at 550 °C for 6 h at a heating rate of 5 °C / min to obtain nano-silica.

[0100] Example 11. A method for preparing dispersed nano-silica, comprising the following steps:

[0101] (1) Heat industrial grade polyisobutylene succinic anhydride to 160°C, stir and add raw material, react for 6 hours to obtain high molecular surfactant, which is grade A; the raw material is diethylenetriamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw material is 1:2.

[0102] (2) Add 20g of base oil, 4mL of ammonia water and 80mL of deionized water to 1g of product A. The concentration of ammonia water is 0.04mol / L. Stir for 1h, then add 0.036-0.140mL of tetraethyl orthosilicate. React for 3.5h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 100℃ for 24h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0103] (3) Add 10 mL of ethyl acetate and 10 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 80 °C for 3 h, and calcine at 550 °C for 6 h at a heating rate of 5 °C / min to obtain nano-silica.

[0104] Example 12. A method for preparing dispersed nano-silica, comprising the following steps:

[0105] (1) Heat industrial grade polyisobutylene succinic anhydride to 160°C, stir and add raw material, react for 6 hours to obtain high molecular surfactant, which is grade A; the raw material is diethylenetriamine; the molar ratio of industrial grade polyisobutylene succinic anhydride to raw material is 1:2.

[0106] (2) Add 20g of base oil, 4mL of ammonia water and 80mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.08mol / L. Stir for 1h, then add 7.2mL of tetraethyl orthosilicate. React for 3.5h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 100℃ for 24h to obtain a crystallized solution, which is product B. The base oil is base oil SN150.

[0107] (3) Add 10 mL of ethyl acetate and 10 mL of anhydrous ethanol to 5 mL of product B, sonicate, centrifuge, dry at 80 °C for 3 h, and calcine at 550 °C for 6 h at a heating rate of 5 °C / min to obtain nano-silica.

[0108] Examples 10-12 tested the effects of varying oil-water ratios, tetraethyl orthosilicate concentrations, and ammonia concentrations on the morphology of silica.

[0109] Example 10 describes nano-silica prepared by the present invention using polyisobutylene succinic anhydride-diethylenetriamine in a molar ratio of 1:2 at different base oil and deionized water ratios (g / mL). Figure 10 , among which Figure 10 When the ratio of base oil to deionized water in A is 1:9, the particle size distribution range is 8-20nm, concentrated in 9-11nm. The aqueous phase has a larger volume, and the silica obtained from hydrolysis will enter the aqueous phase through the gaps at the oil-water interface. Due to hydration, the surfactant and the head of silica are tightly adsorbed together, preventing the silica from agglomerating during the collision process, thus obtaining dispersed nano silica with a particle size concentrated in 9-11nm. Figure 10When the ratio of base oil to deionized water in B is 2:8, the particle size distribution ranges from 4 to 16 nm, with a concentration of 8 to 10 nm. The aqueous phase has a larger volume, and the silica obtained from hydrolysis enters the aqueous phase through the gaps at the oil-water interface. Due to hydration, the surfactant and the silica head are tightly adsorbed together, preventing silica agglomeration during collisions, thus resulting in dispersed nano-silica with a particle size concentrated in the 8-10 nm range. Figure 10 When the ratio of base oil to deionized water is 3:7, the volume of the aqueous phase decreases, the collision frequency of silica in the aqueous phase is higher, and nano-silica aggregates to form sheet-like silica. Figure 10 When the ratio of base oil to deionized water in D is 4:6, the particle size distribution range is 100-1200nm. Nano-silica is more likely to aggregate into large silica particles, and the silica particle size is concentrated in the range of 450-500nm. Figure 10 When the ratio of base oil to deionized water in E is 5:5, the particle size distribution range is 100-600nm. Silica is more likely to aggregate into large silica particles, and the particle size of silica is concentrated in the range of 100-200nm.

[0110] Figure 11 These are TEM images of nano-silica prepared by different oil-water ratios of polyisobutylene succinic anhydride-diethylenetriamine with a molar ratio of 1:2 according to the present invention; wherein Figure 11 The ratio of base oil to deionized water in A is 1:9. It can be seen that the morphology of monodisperse nano silica is irregular. This is because tetraethyl orthosilicate hydrolyzes in the oil phase. When the amount of oil phase providing tetraethyl orthosilicate for hydrolysis is small, the nano silica is more dispersed, but the morphology is irregular. Figure 11 The ratio of base oil to deionized water in B is 2:8. It can be seen that the dispersed nano-silica exhibits a regular spherical morphology. Figure 10 B corresponds to; Figure 11 The ratio of base oil to deionized water in C is 3:7. Severe agglomeration of nano-silica forms a layered structure. Figure 10 C corresponds to; Figure 11 The ratio of base oil to deionized water in D is 4:6, which shows that the agglomeration of nano-silica is more severe. The nano-silica agglomerates and assembles into large-particle-size regular spherical silica. This is because the increase in the oil phase leads to a larger space for nano-silica to collide with each other in the oil phase. Figure 11 The ratio of base oil to deionized water in E is 5:5. It can be seen that the agglomeration of nano silica is more serious. The nano silica agglomerates and assembles into large-diameter regular spherical or broken silica particles. This is because the reduction of the aqueous phase causes some nano silica to enter the aqueous phase. During the collision process, the nano silica agglomerates and assembles into large-diameter regular spherical or broken silica particles.

[0111] Therefore, it can be seen that when the ratio of base oil to deionized water is 2:8, the prepared nano-silica has a better dispersion effect, with a particle size distribution range of 4-16nm and concentrated dispersion in 8-10nm.

[0112] Example 11 shows nano-silica prepared by different tetraethyl orthosilicate concentrations of polyisobutylene succinic anhydride-diethylenetriamine in a molar ratio of 1:2 according to the present invention. Figure 12 SEM images of nano-silica; among which Figure 12 A is a SEM image of the nano-silica prepared by adding 3.6 mL of tetraethyl orthosilicate. It can be seen from the figure that when a small amount of tetraethyl orthosilicate is added, monodisperse silica can be obtained, but the morphology of nano-silica is irregular. The particle size distribution range of silica is 6-20 nm, and it is concentrated in 9-10 nm. Figure 12 SEM image of nano-silica prepared by adding 7.2 mL of tetraethyl orthosilicate to B. The amount of hydrolyzed silica increased, but regular spherical nano-silica can be clearly seen and it is evenly dispersed. The particle size distribution of silica ranges from 5 to 15 nm, and is concentrated in the range of 8 to 10 nm. Figure 12 C is the SEM image of the nano-silica prepared when 10.8 mL of tetraethyl orthosilicate was added. Further addition of tetraethyl orthosilicate revealed that although the particle size of the nano-silica did not change significantly, the morphology of the nano-silica began to agglomerate and became irregular. The particle size distribution range of the silica was 8-15 nm, with the concentration concentrated in the 10-11 nm range. Figure 12 D is a SEM image of the nano-silica prepared by adding 14.0 mL of tetraethyl orthosilicate. It can be seen that the nano-silica is severely agglomerated, with a particle size distribution range of 8-15 nm, concentrated in the 10-11 nm range.

[0113] correspond Figure 12 AD, changing the concentration of tetraethyl orthosilicate does not affect the morphology of silica, but it can significantly improve the aggregation of nano-silica particles, allowing them to form dispersed nano-silica particles. Therefore, the optimal concentration of tetraethyl orthosilicate is 7.2 mL.

[0114] Example 12, nano-silica prepared by the present invention with a molar ratio of 1:2 of polyisobutylene succinic anhydride-diethylenetriamine at different ammonia concentrations, see [reference needed]. Figure 13 SEM image of nano-silica. Figure 13 A is a SEM image of nano-silica prepared with ammonia water concentration of 0.02 mol / L. It can be seen that tetraethyl orthosilicate hydrolyzes to produce a small amount of dispersed nano-silica, but the morphology is irregular. The particle size distribution of silica ranges from 8 to 15 nm, with the concentration concentrated in the 10 to 11 nm range. Figure 13B is the SEM image of nano-silica prepared when the ammonia concentration is 0.04 mol / L. It can be seen that the nano-silica has a good dispersion state and regular morphology. The particle size distribution range of silica is 5-15 nm, and it is concentrated in the range of 7.5-10.5 nm. Figure 13 C is the SEM image of nano-silica prepared when the ammonia concentration is 0.06 mol / L. It can be seen that the nano-silica is severely agglomerated, and the particle size distribution range of silica is 6-20 nm, with the concentration dispersed in the range of 10.5-12 nm. Figure 13 D is the SEM image of nano-silica prepared when the ammonia concentration is 0.08 mol / L. It can be seen that, similar to that when the ammonia concentration is 0.06 mol / L, the nano-silica is severely agglomerated and lacks a clear morphological outline. The particle size distribution of silica ranges from 6 to 14 nm, with the concentration concentrated in the range of 10 to 11.5 nm.

[0115] Changing the ammonia concentration will not affect the morphology and particle size of silica. Figure 13 AD, however, can significantly improve the aggregation of nano-silica particles, enabling them to form monodisperse nano-silica particles. Considering the effect of the yield, the optimal ammonia concentration was determined to be 0.04 mol / L.

Claims

1. A method for preparing dispersed nano-silica, characterized in that: It includes the following steps: (1) Heat industrial grade polyisobutylene succinic anhydride to 140-180 °C, add raw materials while stirring, and react for 4-8 h to obtain a high molecular surfactant, which is grade A; the raw materials are alcohols, amines or alkanolamines with different hydrophilic groups; In step (1), the molar ratio of industrial-grade high-molecular-weight polyisobutylene succinic anhydride to the raw material is 1:0.5-2. (2) Add 18-22g of base oil, 3-4mL of ammonia water and 72-88mL of deionized water to 1g of product A. The concentration of ammonia water is 0.02-0.06 mol / L. Stir for 0.5-1h, then add 6.5-7.5mL of tetraethyl orthosilicate. React for 3-4h to obtain a suspension. Perform a hydrothermal reaction on the suspension at 90-110℃ for 20-28h to obtain a crystallized solution, which is product B. (3) Add ethyl acetate and anhydrous ethanol to product B, sonicate, centrifuge, dry, and calcine to obtain nano-silica.

2. The method for preparing dispersed nano-silica according to claim 1, characterized in that: In step (1), the molar ratio of industrial-grade high-molecular-weight polyisobutylene succinic anhydride to the raw material is 1:1.5-2.

3. The method for preparing dispersed nano-silica according to claim 2, characterized in that: In step (1), the molar ratio of industrial-grade polyisobutylene succinic anhydride to the raw material is 1:

2.

4. The method for preparing dispersed nano-silica according to claim 1, characterized in that: In step (1), the alcohols with different hydrophilic groups are ethylene glycol, diethylene glycol or triethylene glycol; the amines are urea, diethylenetriamine or triethylenetetramine; and the alcohol amines are N,N-dimethylethanolamine, 2-methylaminoethanol or triethanolamine.

5. The method for preparing dispersed nano-silica according to claim 4, characterized in that: The raw material is an amine.

6. The method for preparing dispersed nano-silica according to claim 5, characterized in that: The amine is diethylenetriamine.

7. The method for preparing dispersed nano-silica according to claim 1, characterized in that: The base oil is base oil SN150.

8. The method for preparing dispersed nano-silica according to claim 1, characterized in that: In step (3), 8-12 mL of ethyl acetate and 8-12 mL of anhydrous ethanol are added to 5 mL of product B, followed by sonication, centrifugation, drying at 70-90℃ for 2-4 h, and calcination at 520-580℃ for 5-7 h at a heating rate of 4-6℃ / min to obtain nano-silica.

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