Method for preparing amphiphilic nano silica powder and method for preparing Pickering emulsion using same

A nano-silica and amphiphilic technology, which is applied in the manufacture of silica, silicon oxide, and nanostructures, can solve the problems of time-consuming, difficult operation, and inability to form Pickering emulsions, etc., and achieve the effect of short preparation process

Inactive Publication Date: 2010-05-12
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the directly synthesized nano-silica exhibits strong hydrophilicity due to the large number of hydroxyl groups on the surface, and cannot form a stable Pickering emulsion.
[0003] Document 1 "K. Zhang, W. Wu, H. Meng et al. Pickering emulsion polymerization: Preparation of polystyrene / nano-SiO 2 Composite microspheres with core-shell structure. Powder Technology 190 (2009) 393-400." discloses a modified nano-SiO with methacryloxypropyltrimethoxysilane (KH570) 2 According to the method, the contact angle of the obtained powder is 38.5°, and the Pickering emulsion can only be formed under the acidic condition of pH=3, and the stability is not good, and there will be obvious stratification after 24 hours of storage.
[0004] Document 2 "Chinese Invention Patent Publication No. CN 1724352A" discloses a method for preparing amphiphilic nano-silica, which uses amphiphilic block polyether surface modification to prepare amphiphilic nano-silica, but the entire The preparation process requires anion and cation exchange resin treatment, multiple pH adjustments, standing still, reaction and ultrafiltration concentration, etc., which takes a long time and is difficult to operate.

Method used

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  • Method for preparing amphiphilic nano silica powder and method for preparing Pickering emulsion using same
  • Method for preparing amphiphilic nano silica powder and method for preparing Pickering emulsion using same
  • Method for preparing amphiphilic nano silica powder and method for preparing Pickering emulsion using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1: Take 20mL tetraethyl orthosilicate and 200mL methanol, vibrate in an ultrasonic cleaner with a frequency of 40KHz and a power of 250W for 5min; take 40mL ammonia water with a concentration of 25% and add it to 400mL methanol, stir it evenly and pour it into the In the methanol solution of tetraethyl orthosilicate oscillated by ultrasound, continue to react under ultrasound for 3 hours. The whole process is cooled by circulating water, and the water temperature is kept at 15°C. Finally, light blue nano-SiO can be obtained. 2 Dispersions. After detection by laser particle size analyzer, Z-Average (d.nm): 42.8nm, particle size polydispersity index (PDI) is 0.149, see the test results figure 1 . The dispersion liquid is stable in nature, and the particle size basically does not change after being stored at room temperature for more than 3 months.

[0023] Take the above nano-SiO 2 Dispersion liquid 100mL, add glacial acetic acid dropwise under pH meter monitor...

Embodiment 2

[0026] Example 2: Take 10mL tetraethyl orthosilicate and 100mL methanol, and vibrate in an ultrasonic cleaner with a frequency of 30KHz and a power of 300W for 6min; take 20mL of ammonia water with a concentration of 26% and add it to 200mL of methanol, stir it evenly, and pour it into the In the methanol solution of tetraethyl orthosilicate oscillated by ultrasonic waves, continue to react under ultrasonic for 2 hours. The whole process is cooled by circulating water, and the water temperature is kept at 18°C. Finally, light blue nano-SiO can be obtained. 2 Dispersions. After detection by laser particle size analyzer, Z-Average (d.nm): 44.1nm, particle size polydispersity index (PDI) is 0.157, see figure 2 .

[0027] Take the above nano-SiO 2 Dispersion liquid 100mL, add glacial acetic acid dropwise under pH meter monitoring and magnetic stirring, adjust the pH value of the dispersion liquid to 7.3, add 0.15mL long-chain alkyltrimethoxysilane (WD-10) after ultrasonic dispers...

Embodiment 3

[0030] Example 3: Take 30mL tetraethyl orthosilicate and 300mL methanol, and vibrate in an ultrasonic cleaner with a frequency of 60KHz and a power of 200W for 8min; take 60mL of ammonia water with a concentration of 27% and add it to 600mL of methanol, stir it evenly, and pour it into the In the methanol solution of tetraethyl orthosilicate oscillated by ultrasound, continue to react for 5 hours under ultrasound. The whole process is cooled by circulating water, and the water temperature is kept at 21°C. Finally, light blue nano-SiO can be obtained. 2 Dispersions. After detection by laser particle size analyzer, Z-Average (d.nm): 43.2nm, particle size polydispersity index (PDI) is 0.173, see Figure 4 .

[0031] Take the above nano-SiO 2 Dispersion liquid 100mL, add glacial acetic acid dropwise under pH meter monitoring and magnetic stirring, adjust the pH value of the dispersion liquid to 7.5, add 0.09mL long-chain alkyltrimethoxysilane (WD-10) after ultrasonic dispersion ...

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Abstract

The invention discloses a method for preparing amphiphilic nano silica powder and is used for preparing nano silica powder with about 90 degrees of a tri-phase contact angle. The method uses ultrasonic preparation, thus having short preparation process; the invention adopts liquid phase modification, thus avoiding processing means such as grinding, calcining and the like which are easy to cause the powder to generate hard particle agglomeration; the invention can prepare better amphiphilic surface (about 90 degrees of tri-phase contact angle) nano silica powder. The invention also discloses a method for preparing Pickering emulsion by using the amphiphilic nano silica powder under the action of ultrasound or cutting, the nano silica powder stably exists in oil-water interface, thus preventing diffused oil (water) droplets to re-agglomerate into big droplets to split phase and stabilizing emulsion. The prepared emulsion can be stored at room temperature without occurrence of demulsification in three months.

Description

technical field [0001] The invention relates to a method for preparing silicon dioxide powder, in particular to a method for preparing amphiphilic nanometer silicon dioxide powder. It also relates to a method for preparing Pickering emulsion by using the amphiphilic nano-silica powder. Background technique [0002] Pickering emulsions are often called solid (particle) stable emulsions. The key to constructing this new type of emulsions is to prepare ultrafine powders with better amphiphilic surfaces, nano-SiO 2 The powder is suitable to be used as a stabilizer to construct Pickering emulsion due to its non-toxic and excellent stability, reinforcement and thickening properties. However, generally directly synthesized nano-silica exhibits strong hydrophilicity due to the large number of hydroxyl groups on the surface, and cannot form a stable Pickering emulsion. [0003] Document 1 "K. Zhang, W. Wu, H. Meng et al. Pickering emulsion polymerization: Preparation of polystyrene...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/18C01B33/14B82B3/00
Inventor 范晓东张卫红田威范伟伟
Owner NORTHWESTERN POLYTECHNICAL UNIV
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