A Method for Continuous Preparation of Silica Airgel Balls Using Vibrating Hydrophobic Surface

Abstract

The invention relates to a method for continuously preparing silica airgel spheres by using a vibrating hydrophobic surface. The specific steps are as follows: 1) mixing silica sol with tetraethyl orthosilicate, absolute ethanol and deionized water and standing for hydrolysis Obtain slurry A; 2) Dilute the fluorine-containing solution with deionized water to obtain slurry B; 3) Pour slurry A and slurry B into a mixer and mix evenly to form a mixed solution, which is pushed into the mixture by a syringe pump Peristaltic pump, the syringe needle connected by the peristaltic pump slowly drips drop by drop onto the vibrating hydrophobic vibrating plate, so that the solution drops drop by drop in the spiral channel of the hydrophobic vibrating plate, ensuring that the solution gels while maintaining the vibrating state, and The gel balls obtained after gelation are rolled and discharged continuously in the spiral channel, and are dropped into absolute ethanol for post-processing to obtain silica airgel balls. The method of the invention combines the sol-gel technology and the vibrating hydrophobic surface to continuously prepare the silicon dioxide airgel balls, which is simple, continuous production, low cost and short cycle.

Description

technical field [0001] The invention belongs to the technical field of airgel materials, and in particular relates to a method for continuously preparing silica airgel balls by using a vibrating hydrophobic surface. Background technique [0002] Airgel is an ultra-low-density material with a porosity of 90% or more and a specific surface area of ​​several hundred to 1500m2 depending on the nanostructure and the type of starting material 2 / g, nanoporous aerogels can be used in applications such as ultra-low dielectric materials, catalysts, electrode materials, and sound insulation materials. [0003] In particular, SiO 2 Due to its unique nano-sized continuous pore structure, airgel has the characteristics of low density, high porosity, high specific surface area, uniform pore distribution, and low thermal conductivity. It can be used in refrigerators, automobiles, aircrafts and other fields. At present, domestic and foreign on the preparation of SiO 2 There are many repo...

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Problems solved by technology

[0004] Li Hongwei used the dropping method to make a hydrophobic platform with silica airgel powder, ion-exchange water glass (modulus n=1.8-2.3) to prepare a sol, adjust the pH value, disperse and drop on the platform, and prepare millimeter-scale Hydrophobic SiO 2 Airgel balls, but the prepared products are easy to adhere to the surface, and the sphericity cannot be guaranteed; Pradip B.Sarawade uses the ball drop method to drop sodium silicate into ammonia solution to prepare airgel balls through sol-gel, and at the same time Using trimethylchlorosilane for surface modification, the sample has a low density (0.081g / cm 3 ) and high specific surface area (917m 2 / g), but the efficiency of this method is low. Simultaneously, due to the short gelation time and the high amount of ammonia water used, the outer surface of the prepared gel beads is easily condensed into a white precipitate, causing quality decline, and the gel beads are finally piled up on the ground. Between the oil phase and the ammonia solution, it is inconvenient to take out, and it is difficult to form a continuous production

[0005] For SiO 2 In the preparation process of airgel balls, the efficiency is low, continuous production is not possible, and the quality is reduced. The present invention provides a method for continuously preparing silica airgel balls by using a vibrating hydrophobic surface to ensure 2 Airgel balls can be produced continuously. At the same time, the prepared airgel balls have the advantages of low density, high specific surface area, and good hydrophobicity.

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