Preparation method of silicon dioxide coated crystal water-salt phase-change material microcapsules

A technology of silicon dioxide and water of crystallization, applied in microcapsule preparations, chemical instruments and methods, microsphere preparation, etc. The effect of variable latent heat, low price and high structural strength

Inactive Publication Date: 2015-09-02
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the wall materials of microcapsules mostly use polymer materials, but they have disadvantages such as easy aging, corrosion, and large thermal resistance. The use of silica wall materials not only solves the above problems but also improves the performance of composite phase change microcapsule materials. thermal conductivity and mechanical strength
U.S. Patent 6156805 provides a method for making microcapsules by wrapping hydrophilic substances with silicon dioxide, but this method cannot obtain microcapsules with highly uniform sizes

Method used

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  • Preparation method of silicon dioxide coated crystal water-salt phase-change material microcapsules
  • Preparation method of silicon dioxide coated crystal water-salt phase-change material microcapsules
  • Preparation method of silicon dioxide coated crystal water-salt phase-change material microcapsules

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Weigh 6.2gCaCl 2 ·6H 2 O was mixed with 10ml of water, and a certain amount of ammonia water was added to adjust the pH to 8 to obtain the mixed solution A. Weigh 0.2g of sodium dodecylbenzenesulfonate and add it to 25ml of cyclohexane and stir at 2000rpm in a water bath at 45°C, add the above-mentioned A mixture to it, and stir for 20min, stale for 2h, and form a stable W / O emulsion. Then add dropwise 1ml of a mixture of ethyl orthosilicate and dimethyldiethoxysilane with a volume ratio of 1:1, then stir at 1000rpm for 24h, then centrifuge in a centrifuge at 5400r / min for 10min to obtain microcapsules , washed three times by centrifugation with deionized water and then dried at 20°C to obtain the product. The latent heat of phase change of the obtained product is 138.122 J / g. Its DSC phase transition curve is shown in figure 1 shown.

Embodiment 2

[0035] Weigh 6g Na 2 SO 4 10H 2 O was mixed with 30ml of water, and a certain amount of ammonia water was added to adjust the pH to 9 to obtain the mixed solution B. Weigh 1.3g SPAN80 and add it to 130ml cyclohexane and stir at 2000rpm in a water bath at 45°C, add the above B mixture into it, and stir for 20min, then stale for 2h to form a stable W / O emulsion. Then dropwise add 25ml of a mixture of ethyl orthosilicate and dimethyldiethoxysilane with a volume ratio of 1:1.2, then stir at 1000rpm for 24h, then centrifuge for 10min in a centrifuge at 5400r / min to obtain microcapsules , washed three times by centrifugation with deionized water and then dried at 20°C to obtain the product. The latent heat of phase change of the obtained product is 120.531 J / g. Its DSC phase transition curve is shown in figure 2 shown.

Embodiment 3

[0037] Weigh 6.2g Na 2 SO 4 10H 2 Mix O with 20ml of water, add a certain amount of ammonia water, adjust the pH to 8, and obtain the mixed solution C. Weigh 0.8g of SDS and add it to 80ml of hexadecane and stir at 2000rpm in a water bath at 45°C, add the above C mixture into it, and stir for 20min, then stale for 2h to form a stable W / O emulsion. Then dropwise add 2ml of a mixture of ethyl orthosilicate and dimethyldiethoxysilane with a volume ratio of 1:1.5, then stir at 1000rpm for 24h, then centrifuge in a centrifuge at 5400r / min for 10min to obtain microcapsules , washed three times by centrifugation with deionized water and then dried at 20°C to obtain the product. The latent heat of phase change of the obtained product is 154.009 J / g. Its DSC phase transition curve is shown in image 3 shown.

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Abstract

The invention discloses a preparation method of silicon dioxide coated crystal water-salt phase-change material microcapsules. The preparation method comprises the steps of regulating the pH of saturated crystal water and a salt solution to the range of 8-10, mixing the saturated crystal water and the salt solution with a surfactant and an organic solvent and stirring for 2-3 hours at a temperature within the range of 40-50 DEG C, thereby obtaining a W / O emulsion, next, dropwise adding a silicon dioxide precursor to the obtained emulsion and stirring for reacting at a room temperature for 20-30 hours, and finally, centrifuging, washing and drying the precipitate obtained through the reaction, thereby obtaining the finished product. The preparation method is simple in process and does no need high-temperature calcination; the preparation process is safe, and the obtained microcapsules are good in tightness and easy to adjust in particle size. The crystal water and the salt are taken as the core materials, and compared with other phase-change materials, the core materials are easily available and low in prices and have great latent heat of phase change.

Description

technical field [0001] The invention belongs to the technical field of composite materials, and in particular relates to a method for preparing microcapsules of crystal water and salt phase-change materials wrapped in silicon dioxide. Background technique [0002] Because phase change heat storage materials are generally accompanied by large energy absorption or release during the phase change process, and have the characteristics of maintaining an approximately isothermal process, they provide a broad basis for the application of thermal energy storage and can be used commercially. To a certain extent, it solves the contradiction of energy utilization mismatch in time and space. Among the existing phase change materials, hydrated salt phase change materials have been widely concerned due to their characteristics of cheap price, large heat of solution, wide application range, large heat of solution and fixed melting point. Such phase change materials mainly include halides,...

Claims

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Application Information

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IPC IPC(8): B01J13/02C09K5/06
Inventor 陶海征单静春安继明张昌湘
Owner WUHAN UNIV OF TECH
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