Phase-change material capsule and preparation method thereof

A technology of phase change materials and capsules, which is applied in the field of phase change materials, can solve the problems of reducing the effective content of n-octadecane, poor anti-supercooling crystallization effect of paraffin, and unsatisfactory research results, achieving good thermal stability and eliminating overcooling. Cold crystallization phenomenon, the effect of facilitating industrial implementation

Active Publication Date: 2011-10-12
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although supercooled crystallization is a common phenomenon in the cooling process of PCM, the supercooled crystallization of PCM in MicroPCMs and NanoPCMs makes the exothermic process occur at a wider temperature range or lower temperature, which seriously affects the energy storage function.
In order to effectively eliminate or reduce the supercooled crystallinity, the inventors studied (see Colloid and Surface Science Journal, Journal of Colloid and Interface Science, 2005, 281 (2): 299-306) the mass fraction of 5-30% Effects of 1-tetradecyl alcohol, 1-stearyl alcohol and paraffin wax with a melting point of 56°C on the supercooled crystallization of n-octadecane in MicroPCMs. As an anti-supercooled crystallization additive, 1-octadecyl alcohol cannot be achieved because it affects cystic formation. to the best effect; when the paraffin mass fraction was 20%, MicroPCMs with lower degree of supercooled crystallization and better encapsulation could be prepared, but the effective content of n-octadecane in MicroPCMs was reduced, and the diameter of MicroPCMs increased The smaller the paraffin, the worse the anti-supercooled crystallization effect
[0004] Other researchers (see Journal of Thermal Analysis and Calorimetry, Journal of Thermal Analysis and Calorimetry, 2006, 86(2): 505-509) added modifiers such as nano-silica to MicroPCMs in an attempt to prevent them from overcooling Crystallization occurs, but results are not ideal

Method used

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Effect test

preparation example Construction

[0052] The present invention has simultaneously designed the preparation method (abbreviation preparation method) of capsule, and this preparation method adopts the mass fraction composition of capsule of the present invention and following technology: the polymerization monomer of described mass fraction, phase-change material, emulsifier and initiator agent, and dispersant, and then the mixture is mechanically stirred or ultrasonically oscillated at a temperature of 10-90°C, and the particle size of the emulsion droplet in the emulsion is observed at any time with an optical microscope or an environmental scanning electron microscope until the particle size of the emulsion droplet reaches The design requirement is 1-1000 micron or below 1 micron, and then under the action of the initiator, the monomer is polymerized, and the phase change material capsule is prepared by the suspension polymerization method or the in-situ polymerization method. In the process of preparing phase...

Embodiment 1

[0065] At 90°C, 9 g of pentadecyl acrylate, 35 g of methyl acrylate, 6 g of ethylene glycol dimethacrylate, 164 g of phase change material n-octadecane, 2 g of initiator azobisisoheptanonitrile, and 780 g of deionized water, Mix emulsifier sodium lauryl sulfate 4g, mechanically stir at 9000rpm for 2 hours, the average diameter of emulsion droplets is 0.7 microns, and then stir at 500rpm for 6 hours; stop stirring, cool down to room temperature through water circulation, filter and separate the mixed emulsion, and remove it with 2500g of mass. After rinsing the product with ion water for 3 times, it was dried in a vacuum oven at 50° C. to a constant weight to obtain dry powder of phase change material nanocapsules.

[0066] After testing, the average particle diameter of the obtained phase-change material nanocapsules is 0.9 micron, and the crystallization melting endothermic temperature (T m ) is 28.5°C, the heat of fusion (ΔH m ) is 181J / g, crystallization exothermic tempera...

Embodiment 2

[0068] At 90°C, 2 g of tritetradecyl acrylate, 46 g of methyl methacrylate, 2 g of pentaerythritol tetraacrylate, 164 g of lipophilic phase change material n-hexadecane, 2 g of initiator azobisisoheptanonitrile, and emulsifier dodecyl Mix 4 g of alkyl potassium sulfate and 780 g of deionized water, stir at 10,000 rpm for 2 hours, the average diameter of the emulsion droplets is 0.4 microns, and stir at 600 rpm for 6 hours; stop stirring, and obtain phase change material nanocapsule emulsion.

[0069] After testing, the average particle diameter of the obtained phase change material microcapsules is 0.6 micron, T m is 18.7℃, ΔHm is 178J / g, T c Compared with n-hexadecane, there is no obvious supercooled crystallization phenomenon, ΔH c 176J / g, T d is 255°C.

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Abstract

The invention discloses a phase-change material capsule and a preparation method thereof. The capsule uses a phase-change material as a capsule core and is characterized in that: a capsule wall material of the capsule at least comprises a monomer I polymer. The phase-change material capsule comprises the following materials in percentage by mass: 20.8 to 84.3 percent of phase-change material, 9 to 72.5 percent of monomer I, 0.4 to 4.5 percent of emulsifying agent and 0.1 to 2.2 percent of initiator, wherein the monomer I is a monomer comprising a crystallizable branch and comprises but not limited to at least one of crylic acid alkyl ester of which the branch contains 10 to 50 carbon atoms or methacrylic acid alkyl ester of 10 to 50 carbon atoms; the alkyl has a straight chain structure; the emulsifying agent is a micromolecule emulsifying agent and comprises an anionic, cationic, nonionic or polymer emulsifying agent; and the initiator comprises but not limited to a radical initiator or an oxidation-reduction initiator. In the preparation method, the phase-change material capsule is prepared by a suspension polymerization method or an in-situ polymerization method.

Description

technical field [0001] The invention relates to phase change material technology, in particular to a phase change material capsule and a preparation method thereof. The capsule is a phase change material microcapsule or nanocapsule with functions of heat energy storage and utilization. Background technique [0002] Clean and green energy storage materials have a particularly important strategic position in the national economy and have been a research focus for a long time. Phase change material (PCM) is an energy-saving and environmentally friendly material developed and applied after the 1970s, and it is also a clean and recyclable energy storage material. Phase change materials can absorb or release a large amount of latent heat during solid-liquid, solid-gas, liquid-gas, and solid-solid phase transitions, and are widely used in HVAC, energy-saving buildings, solar energy utilization, and clothing. , which is of great significance in terms of "energy saving and emission ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K5/06B01J13/14
Inventor 张兴祥王建平石海峰王学晨廖晓华
Owner TIANJIN POLYTECHNIC UNIV
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