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CN-121975494-A - Phase-change microcapsule and preparation method thereof

CN121975494ACN 121975494 ACN121975494 ACN 121975494ACN-121975494-A

Abstract

The invention relates to a method for preparing phase-change microcapsules by taking Pickering emulsion as a template. According to the method, an organic phase change material is used as an oil phase, the oil-in-water Pickering emulsion is stabilized through electrostatic co-assembly of a nanoparticle-polymer interface, and a microcapsule shell layer with excellent mechanical strength is constructed by utilizing interface blockage transformation of the nanoparticle, so that stable preparation of the phase change microcapsule is realized. The invention avoids the polymerization reaction necessary in the traditional phase-change microcapsule shell chemical method preparation, has the advantages of simple operation, excellent coating effect, low cost and environmental protection, and the phase-change microcapsule prepared by the method can be applied to the fields of building materials, textiles, heat transfer fluid, cold chain transportation and the like.

Inventors

  • SHI SHAOWEI
  • Sun Danzhong

Assignees

  • 北京化工大学

Dates

Publication Date
20260505
Application Date
20250113

Claims (10)

  1. 1. The preparation method of the phase-change microcapsule is characterized by comprising the following steps: s1) preparing an oil phase solution by using a polymer ligand/oligomer ligand and an organic phase change material, wherein the temperature of the oil phase solution is higher than the phase change temperature of the organic phase change material, and the weight of the polymer ligand/oligomer ligand is 0.1% -20% of the weight of the oil phase solution; S2) preparing an aqueous phase solution by using nano particles and ultrapure water, and adjusting the pH value of the aqueous phase solution by using a pH regulator, wherein the pH value of the aqueous phase solution after the pH value adjustment is 2-12, and the weight of the nano particles is 0.1% -20% of the weight of the aqueous phase solution; S3) mixing the oil phase solution prepared in the step S1) and the aqueous phase solution with the pH value adjusted prepared in the step S2) to prepare a mixed solution, raising the temperature of the mixed solution to be above the phase transition temperature of the organic phase change material, and then performing emulsification treatment on the mixed solution to obtain an oil-in-water Pickering emulsion; And S4) cooling the Pickering emulsion prepared in the step S3) to room temperature, centrifuging to remove the aqueous phase solution in the Pickering emulsion, and drying to obtain the phase-change microcapsule, wherein the centrifuging speed is 3000-6000 rpm when the aqueous phase solution in the Pickering emulsion is removed by centrifuging.
  2. 2. The phase-change microcapsule preparation method according to claim 1, wherein nanoparticles in the Pickering emulsion in the step S3) are in an interface blocking state, and the particle size of the emulsion in the Pickering emulsion is 10-100 μm.
  3. 3. The method for preparing phase-change microcapsules according to claim 1, wherein the particle size of the phase-change microcapsules prepared in step S4) is 10-100 μm.
  4. 4. The phase-change microcapsule preparation method according to claim 1, wherein in the step S3), the volume of the oil phase solution is 5-50% of the volume of the mixed solution.
  5. 5. A phase-change microcapsule, wherein the phase-change microcapsule is a microcapsule produced by the phase-change microcapsule production method according to claim 1.
  6. 6. The phase change microcapsule of claim 5, wherein the nanoparticle is a surface-modified negatively charged nanomaterial.
  7. 7. The phase change microcapsule of claim 6, wherein the nanoparticles are one or more of inorganic nanoparticles of different dimensions and organic nanoparticles of different dimensions.
  8. 8. The phase-change microcapsule according to claim 5, wherein the organic phase-change material is one or more of a paraffin-based phase-change material, a fatty acid-based phase-change material, a fatty alcohol-based phase-change material, and a polymer-based phase-change material.
  9. 9. The phase-change microcapsule according to claim 5, wherein the pH adjustor is an acidic substance or an alkaline substance, and the weight of the pH adjustor is 0.1-10% of the weight of the aqueous phase solution.
  10. 10. The phase change microcapsule according to claim 5, wherein the polymer ligands are aminated polymer or/and quaternized polymer ligands and the oligomer ligands are aminated oligomer ligands and/or quaternized oligomer ligands.

Description

Phase-change microcapsule and preparation method thereof Technical Field The invention belongs to the field of material preparation, and relates to a phase-change microcapsule and a preparation method thereof. Background The phase change material is an effective heat storage material, and can absorb or release a large amount of heat from the surrounding environment in the form of latent heat in the phase change process, and has the advantages of high energy storage density, constant phase change temperature, less heat loss and the like compared with other heat storage modes. Among them, organic phase change materials are becoming a research hot spot in industry and academia by virtue of their low supercooling degree, high latent heat of phase change, and excellent thermal stability. However, the organic phase change material is subject to stability problems such as leakage or morphology collapse in a molten state, which greatly restricts the development of the organic phase change material in practical application. Therefore, it is generally prepared into phase-change microcapsules by microencapsulation technology. The phase change microcapsule is prepared by using microcapsule technology and adopting a material with stable chemical properties as a shell material to wrap a phase change substance, so that the microsphere with a core-shell structure is formed, the phase change material can be effectively isolated from the outside, the possible reaction with the environment is delayed, the leakage problem of the phase change material in the use process is effectively solved, and the microsphere has excellent thermal stability and mechanical stability. The chemical method for microencapsulating the phase change material includes an in-situ polymerization method, a suspension polymerization method, an interfacial polymerization method, an emulsion polymerization method and the like. The Pickering emulsion polymerization method is a novel emulsion polymerization mode which uses solid particles to replace the traditional surfactant. The phase change microcapsule material prepared by the Pickering emulsion polymerization method has the advantages that on one hand, solid particles can participate in shell formation, and the heat conductivity, mechanical strength, leakage resistance and the like of a polymer shell are improved. On the other hand, the absence of a surfactant avoids its environmental pollution. However, the preparation of stable microcapsule shells by polymerization requires not only the selection of suitable monomers, but also the regulation and control of various reaction parameters, and the process is complicated and the cost is high. In recent years, a method of stabilizing Pickering emulsions using a synergistic assembly of solid particles and polymeric ligands has attracted attention from researchers (Angew.chem.int.Ed.2018, 57, 13560-13564). Particularly, the blocking transition of solid particles at the emulsion interface can be utilized to remarkably improve the mechanical strength of the interface film and the structural stability of the Pickering emulsion, and meanwhile, the change of the liquid drop morphology driven by the interfacial tension can be restrained, so that the preparation of the anisotropic Pickering emulsion is realized. The phase-change microcapsule prepared by the method is hopeful to avoid chemical preparation of microcapsule shells, is environment-friendly, and greatly simplifies the preparation flow of the phase-change microcapsule. At present, no related research and report are found at home and abroad. Therefore, it is important to develop a method for preparing phase-change microcapsules using interfacial plug transition. Disclosure of Invention Therefore, the technical problem to be solved by the invention is to provide a method for preparing phase-change microcapsules in a large scale with low cost, which uses an organic phase-change material as an oil phase, uses nanoparticle-polymer interface static co-assembly to stabilize oil-in-water Pickering emulsion, and uses interface blocking transition (Jamming transition) of nanoparticles to physically construct microcapsule shells with excellent mechanical strength, thereby realizing stable preparation of phase-change microcapsules. In order to solve the technical problems, the invention provides the following technical scheme: A phase-change microcapsule preparation method comprises the following steps: s1) preparing an oil phase solution by using a polymer ligand/oligomer ligand and an organic phase change material, wherein the temperature of the oil phase solution is higher than the phase change temperature of the organic phase change material, and the weight of the polymer ligand/oligomer ligand is 0.1% -20% of the weight of the oil phase solution; S2) preparing an aqueous phase solution by using nano particles and ultrapure water, and adjusting the pH value of the aqueous phase solution by using a pH regulator, whe