Phase-change microcapsules for inorganic metal oxide coated hydrous salt and preparation method

Abstract

The invention belongs to the technical field of phase-change materials and particularly relates to a method for preparing phase-change microcapsules for inorganic metal oxide coated hydrous salt withanti-solvent and sol-gel technologies. The method comprises steps as follows: (1), metal alkoxide with M(OR)n structure is added to a solvent at the room temperature under the stirring condition, anda homogeneous solution A is formed; hydrous salt and a catalyst are added to distilled water, and a catalyst-containing saturated salt solution B is prepared; (2), the solution B is slowly dropwise added to the solution A; after dropwise adding, the stirring rate is reduced and the reaction is continued for 2-10 h, and a phase-change microcapsule suspension is obtained; (3), the suspension is centrifugally separated, drip washing and drying are executed, and a product is obtained; an anti-solvent in a filtrate can be recycled through distillation. The obtained phase-change microcapsules have the characteristics of adopting simple technologies and being environmentally friendly, high in product phase change enthalpy and high in heat conductivity coefficient; the problems of hydrous salt corrosion, crystallization water loss, supercooling, phase separation and the like can be solved, and the phase-change microcapsules are applied to occasions of phase-change thermal storage in building energy conservation.

Description

technical field [0001] The invention belongs to the technical field of phase-change materials, and in particular relates to a phase-change microcapsule prepared by an anti-solvent and sol-gel process and a hydrated salt coated with an inorganic metal oxide and a preparation method thereof. Background technique [0002] Inorganic hydrated salts are widely used as phase change heat storage materials (PCMs) in the field of building energy conservation due to their wide sources, low price, adjustable temperature, high volumetric energy density, and high thermal conductivity. However, crystalline hydrated salt PCMs have problems such as supercooling, phase separation, corrosion, and easy loss of crystal water, which limit its application. Encapsulation of hydrated salt PCMs into phase change microcapsules with core-shell structure is one of the important ways to effectively solve the practical application of PCMs. It not only solves the problems of corrosion and water loss, but ...

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Problems solved by technology

However, the process does not involve particle size testing (particle size analysis), enthalpy measurement (DSC analysis), and the phase transition temperature of the synthetic capsule is 34.6°C, which is lower than that of pure disodium hydrogen phosphate dodecahydrate (37°C). Strictly speaking, the nanocapsule core material may contain excess water in addition to DSP

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