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CN-122006608-A - Preparation method of photo-thermal response thermochromic microcapsule

CN122006608ACN 122006608 ACN122006608 ACN 122006608ACN-122006608-A

Abstract

The invention discloses a preparation method of a photo-thermal response type thermochromic microcapsule, and relates to the technical field of thermochromic materials. In recent years, phase change materials, thermochromic materials and photothermal conversion materials show good application potential in the low-temperature deicing direction, but single-function materials often have difficulty in meeting the requirements of deicing efficiency, response speed and stability at the same time. The preparation method comprises the steps of preparing a core material composite solution, dropwise adding the core material composite solution into a diluted SMA alkaline solution, emulsifying to obtain emulsion, preparing MUF prepolymer, adding the MUF prepolymer into the emulsion to obtain a mixture, diluting the mixture, adjusting the pH to 4.0-4.5 to obtain a reaction solution, carrying out acid catalyzed polycondensation on the reaction solution, adjusting the pH to 6.8-7.25, stirring the reaction solution to 10-20 min to obtain microcapsule suspension, washing the microcapsule suspension, filtering the microcapsule suspension, and drying the microcapsule suspension to constant weight to obtain the photothermal response thermochromic microcapsule with photothermal response, thermochromic indication and phase change heat storage characteristics.

Inventors

  • WANG PEI
  • ZHANG CHI
  • WANG ZHANFENG
  • LIU XUANRUI
  • SUN PEIYING
  • MAO HAOYU
  • WANG MEICHEN

Assignees

  • 陕西交通职业技术学院

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The preparation method of the photothermal response thermochromic microcapsule is characterized by comprising the following steps of: (1) Preparing a core material composite solution; (2) Preparing a styrene-maleic anhydride copolymer alkaline solution, and diluting to obtain a diluted styrene-maleic anhydride copolymer alkaline solution; (3) Dripping the core material composite solution into the diluted styrene-maleic anhydride copolymer alkaline solution, adding deionized water, and emulsifying under the condition of mechanical stirring to obtain emulsion; (4) Preparing melamine-urea-formaldehyde prepolymer, adding the melamine-urea-formaldehyde prepolymer into emulsion at a speed of 3.0-10.0mL/min to obtain a mixture, adding deionized water to obtain a diluted mixture, and adding an acid regulator to adjust the pH value of the diluted mixture to 4.0-4.5 to obtain a reaction solution; (5) Carrying out acid-catalyzed polycondensation on the reaction liquid under the condition of mechanical stirring to form a melamine-urea-formaldehyde shell layer coating the core material, adding an alkaline regulator to adjust the pH value to 6.8-7.25 after the acid-catalyzed polycondensation is finished, and stirring for 10-20min to obtain microcapsule suspension; (6) And washing, filtering and drying the microcapsule suspension to constant weight to obtain the photothermal response thermochromic microcapsule.
  2. 2. The method for preparing a photothermal response thermochromic microcapsule according to claim 1, wherein in the preparation process of the core material composite solution, crystal violet lactone and bisphenol A are mixed according to a mass ratio of 1:1-1:5 to obtain a color-developing agent mixture; heating 8-12g of pelargonic acid to 60-65 ℃, adding a color reagent mixture, adding 2mL of isopropanol, and stirring for 50-70min at a constant temperature of 800-1000r/min under the condition of 65-75 ℃ at a mechanical stirring rate, so that the mixture is uniformly mixed, and a core material composite solution is obtained.
  3. 3. The method for preparing a photothermal responsive thermochromic microcapsule according to claim 2, wherein the mass ratio of crystal violet lactone to bisphenol A is 1:3.
  4. 4. The method for preparing a photo-thermal response type thermochromic microcapsule according to claim 3, wherein in the process of preparing a styrene-maleic anhydride copolymer alkaline solution and diluting to obtain a diluted styrene-maleic anhydride copolymer alkaline solution, Mixing the styrene-maleic anhydride copolymer with 3M sodium hydroxide, stirring for 30min at 70 ℃, adding deionized water every 30min after stirring, and adding deionized water for 6 times; after the reaction is finished, an acidic regulator is dripped to adjust the pH value to 10, so as to obtain 2wt% of styrene-maleic anhydride copolymer alkaline solution; Adding deionized water into 2wt% of styrene-maleic anhydride copolymer alkaline solution, stirring for 30min at 70 ℃ with the mass ratio of the deionized water to the styrene-maleic anhydride copolymer alkaline solution being 5:1, and obtaining diluted styrene-maleic anhydride copolymer alkaline solution.
  5. 5. The method for preparing a photo-thermal response type thermochromic microcapsule according to claim 4, wherein the core material composite solution is dripped into a diluted styrene-maleic anhydride copolymer emulsification system, deionized water is added, and the emulsification temperature is 65-75 ℃ and the mechanical stirring speed is 800-1000r/min and the emulsification time is 50-70min in the emulsification process under the mechanical stirring condition.
  6. 6. The preparation method of the photo-thermal response thermochromic microcapsule according to claim 5, wherein the preparation method of the melamine-urea-formaldehyde prepolymer is characterized in that urea, melamine, formaldehyde aqueous solution and deionized water are mixed, nano titanium dioxide is added and mechanically stirred for 10min under the condition of 70 ℃ water bath, an alkaline regulator is added to regulate the pH value to 10.0+/-0.1, and the stirring reaction is continued for 1h at 70 ℃ to obtain the melamine-urea-formaldehyde prepolymer; Wherein the mass ratio of urea to melamine is 1.625:1, the mass ratio of 37wt% formaldehyde aqueous solution to deionized water is 1.85:1, the dosage of urea is 1.82-2.73g, and the dosage of deionized water is 4-6mL.
  7. 7. The method for preparing a photo-thermal response type thermochromic microcapsule according to claim 6, wherein the reaction temperature of the acid catalyzed polycondensation is 80-95 ℃, the mechanical stirring rate is 800-1500r/min, and the reaction time is 90-160min.
  8. 8. The preparation method of the photothermal responsive thermochromic microcapsule according to claim 7, wherein the particle size of the nano titanium dioxide is 10-200nm, and the addition amount is 0.1-5wt% based on the mass of the melamine-urea-formaldehyde prepolymer.
  9. 9. The photothermal response thermochromic microcapsule is characterized by comprising a core material and a shell layer wrapping the core material; wherein the core material is prepared from the following raw materials, by weight, 8-12g of pelargonic acid, and the mass ratio of crystal violet lactone to bisphenol A is 1:1-1:5; the shell layer is prepared from the following raw materials in parts by weight, wherein the solid mass ratio of urea to melamine to formaldehyde is 1.625:1:2.445; The shell layer is dispersed with nano titanium dioxide, and the addition amount of the nano titanium dioxide is 0.1-5wt% of the mass of the shell layer.
  10. 10. The photo-thermal response type thermochromic microcapsule according to claim 9, wherein the particle size of the photo-thermal response type thermochromic microcapsule is 5-50 μm.

Description

Preparation method of photo-thermal response thermochromic microcapsule Technical Field The invention relates to the technical field of functional microcapsule materials, in particular to a preparation method of a photo-thermal response type thermochromic microcapsule integrating photo-thermal conversion, thermochromic and phase-change heat storage functions, which can be applied to a building envelope, a functional coating and a temperature regulation and protection material in a low-temperature environment. Background In northeast, northwest, qinghai-Tibet plateau and other areas of China, the phenomena of photovoltaic modules, bridge steel structures, icing and snow covering on the outer surfaces of buildings and the like often occur in winter and transitional seasons, and the problems of bearing capacity reduction, surface adhesion enhancement, operation efficiency reduction and the like are easily caused, so that the safety of infrastructure and energy utilization are affected. The deicing/anti-icing modes commonly used at the present stage comprise electric heating, chemical deicing agent spraying, mechanical cleaning and the like, but the defects of high energy consumption, corrosiveness to a base material, high construction and maintenance cost, difficulty in realizing fine and intelligent management and the like are generally existed, and the requirements of green low carbon and long-term stable operation are difficult to meet. Therefore, developing a surface protection material with the characteristics of environmental friendliness, sustainability and multifunctional synergy has become a research hotspot in the fields of anti-icing and thermal management of cold area components. In the material layer, the phase change energy storage material, the thermochromic material and the photothermal conversion material have application potential in thermal response regulation and control of a low-temperature environment. The phase change material can buffer temperature change by absorbing or releasing latent heat in a phase change temperature region, so that the temperature fluctuation range is reduced, thermal shock in the icing-deicing process is delayed, the thermochromic system can reversibly change color along with the temperature change, light absorption can be regulated to a certain extent, visual temperature indication can be provided, the photothermal material can absorb solar radiation and quickly convert into heat energy, and the surface temperature of a component is promoted to cross 0 ℃ and enter a key freezing and thawing window for deicing or inhibiting refreezing. However, the existing researches focus on the improvement of a single function, and the cooperative integration of 'quick temperature rise under illumination-visual temperature indication-latent heat buffering and slow freeze-back' is difficult to realize while the structural stability and the circulation durability are ensured, and in addition, the problems of leakage, color development attenuation or unstable response and the like of a phase-change core material easily occur under the actual working conditions of repeated freeze-thawing circulation, illumination-cooling alternation and the like of a single functional system, so that the long-term application of the phase-change core material in a coating and composite structure is limited. Disclosure of Invention Aiming at the problems that the phase change energy storage material, the thermochromic material and the photo-thermal material in the prior art are single in function, the structural stability and the circulation durability are difficult to be considered, core material leakage, color development attenuation or unstable response and the like are easy to occur in coating or composite application, the invention aims to provide a preparation method of a photo-thermal response type thermochromic microcapsule, and the synergistic effect of photo-thermal heating, thermochromic visualization and phase change heat storage is realized through process condition control, so that the stability and the application suitability of the material under the alternate working conditions of freezing and thawing and illumination are improved. In order to achieve the above purpose, the invention provides a preparation method of a photo-thermal response thermochromic microcapsule, which comprises the following steps: (1) Preparing a core material composite solution; (2) Preparing a styrene-maleic anhydride copolymer alkaline solution, and diluting to obtain a diluted styrene-maleic anhydride copolymer alkaline solution; (3) Dripping the core material composite solution into the diluted styrene-maleic anhydride copolymer alkaline solution, adding deionized water, and emulsifying under the condition of mechanical stirring to obtain emulsion; (4) Preparing melamine-urea-formaldehyde prepolymer, adding the melamine-urea-formaldehyde prepolymer into emulsion at a speed of 3.0-10.0mL/min to obtain a