CN-122012026-A - Reversible thermochromic phase change capsule heat storage material and preparation method thereof

CN122012026ACN 122012026 ACN122012026 ACN 122012026ACN-122012026-A

Abstract

A reversible thermochromic phase change capsule heat storage material and a preparation method thereof belong to the technical field of thermochromic phase change energy storage capsule coating. The core material of the thermochromic phase-change capsule is polysorbate-80 emulsified 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminobenzene peptide, 2-bis (4-hydroxyphenyl) propane, an alcohol phase-change material and a sodium alginate solution to form a sodium alginate-based thermochromic phase-change emulsion, and the wall material of the thermochromic phase-change capsule is calcium alginate generated by performing ion exchange reaction on sodium alginate and Ca 2+ in a CaCl 2 solution. The non-toxic low-cost natural biopolymer sodium alginate is selected as a matrix material for stabilizing the thermochromic phase-change material and the generated calcium alginate is selected as a shell material. The material can flexibly respond to color change along with temperature change, has good light-heat interface cooperativity and high light-heat conversion efficiency, and greatly expands the application potential of the reversible thermochromic phase change capsule in the fields of temperature indication, anti-counterfeiting mark, thermal management system, solar light-heat utilization and the like.

Inventors

LIU CHENZHEN
HUANG KUN
Rao zhonghao
ZHANG GUANGTONG
YANG PENG
TAO JUNPU
ZHANG ZHANHUI

Assignees

河北工业大学
中材节能股份有限公司

Dates

Publication Date: 20260512
Application Date: 20251218
Priority Date: 20241226

Claims (10)

1. The reversible thermochromic phase change capsule heat storage material is characterized by comprising the following required raw materials, namely thermochromic phase change material, 1-2.5% of alginate solution, nonionic surfactant and more than 20% of calcium chloride solution by mass percent, wherein the reversible thermochromic phase change capsule heat storage material is prepared from the raw materials; The composition of the thermochromic phase-change material is 1.56% of 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminobenzene peptide, a color former and a determined color; 4.69% by mass of 2, 2-bis (4-hydroxyphenyl) propane, a color developing agent, and determining the color shade; 93.75 percent of alcohol phase-change material and solvent by mass percent, and determining the color-changing temperature range; the phase transition temperature of the alcohol phase transition material is within the range of 36-72 ℃ and is selected from n-tetradecanol, n-hexadecanol, n-octadecanol, n-eicosyl alcohol or n-eicosyl glycol; The nonionic surfactant is selected from polysorbate, polyoxyethylene fatty acid esters and polyoxyethylene fatty alcohol ethers, and the polysorbate nonionic surfactant is selected from polysorbate-80.
2. The reversible thermochromic phase-change capsule of claim 1, wherein the core material of the reversible thermochromic phase-change capsule is a thermochromic phase-change material emulsified by polysorbate-80 and a sodium alginate-based thermochromic phase-change emulsion, and the wall material of the reversible thermochromic phase-change capsule is sodium alginate and Ca 2+ in a calcium chloride solution to perform an ion exchange reaction to generate calcium alginate.
3. The method for preparing the reversible thermochromic phase-change capsule heat storage material according to claim 1, which is characterized by comprising the following specific experimental steps of preparing a core material thermochromic phase-change material, preparing a shell material sodium alginate solution, preparing a reversible thermochromic phase-change emulsion, preparing a CaCl 2 solution and instilling the reversible thermochromic phase-change emulsion into balls: (1) Heating tetradecanol in constant temperature oil bath until the tetradecanol is melted into clear and transparent oil phase, then sequentially adding 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminobenzene peptide and 2, 2-bis (4-hydroxyphenyl) propane, and then stirring the mixture solution by a magnetic stirrer until no obvious particles exist in the mixture solution to obtain a clear and transparent reversible thermochromic phase-change material; (2) Preparing a shell material sodium alginate solution; (3) Adding the materials obtained in the step (1) and the step (2) into a beaker, continuously adding polysorbate-80, and stirring in a constant-temperature oil bath to obtain core material reversible thermochromic phase-change emulsion; (4) Preparing a calcium chloride solution; (5) Instilling the reversible thermochromic phase-change emulsion into balls, namely loading the reversible thermochromic phase-change emulsion obtained in the step (3) into instilling needle tubes, then uniformly instilling the reversible thermochromic phase-change emulsion into CaCl 2 solution obtained in the step (4) after adjusting the speed and the height of a propeller, and then taking out the spherical phase-change emulsion after crosslinking in CaCl 2 solution to obtain the reversible thermochromic phase-change capsule in a wet state; (6) Filtering the obtained product by a suction filtration device, washing with deionized water, and drying in an oven to obtain the dried reversible thermochromic phase-change capsule.
4. A method of preparation as claimed in claim 3, wherein: (2) The preparation of the shell material sodium alginate solution comprises the steps of adding sodium alginate powder into a beaker containing deionized water, stirring in a constant-temperature oil bath, then keeping the stirring speed, naturally cooling to room temperature, and then stirring at room temperature until the sodium alginate powder is completely dissolved into a clear sodium alginate solution; (4) The preparation of the calcium chloride solution comprises the steps of adding calcium chloride particles into a beaker containing deionized water, stirring at room temperature until the calcium chloride particles are completely dissolved, and filtering the obtained solution through a suction filtration device to obtain a clear and transparent CaCl 2 solution without impurities.
5. The method of claim 4, wherein in the step (1), the temperature of the oil bath is 10-20 ℃ higher than the melting point temperature of the alcohol phase-change material, the magnetic stirring speed is 300-600rpm, and the magnetic stirring rotor is C-shaped 。
6. The preparation method according to claim 5, wherein in the step (2), the temperature of the oil bath is 50-60 ℃, the magnetic stirring speed is 2000-2500rpm, the stirring time is 2-3 hours, and the stirring time is 12-18 hours after the temperature is cooled down by naturally cooling the oil bath to room temperature in an oil bath pot with a power supply turned off.
7. The process according to claim 6, wherein in the step (3), the oil bath temperature is 50 to 60 ℃, the magnetic stirring speed is 1000 to 1500rpm, and the stirring time is 1 to 2 hours.
8. The method according to claim 7, wherein in the step (4), the magnetic stirring speed is 300 to 600rpm.
9. The method according to claim 3, wherein in the step (5), the size of the infusion needle tube is 0.5-2mm, the speed of the pusher is 0.5-2mm/min, the infusion height is 10-30cm, and the crosslinking time is 2-3 hours.
10. The process according to claim 3, wherein in the step (6), the washing is performed 2 to 3 times, the drying temperature is 50 to 60 ℃ and the drying time is 12 to 14 hours.

Description

Reversible thermochromic phase change capsule heat storage material and preparation method thereof Technical Field The invention relates to the technical field of thermochromic phase-change energy storage capsule coating, in particular to a preparation method of a reversible thermochromic phase-change capsule heat storage material with calcium alginate as a wall material and a sodium alginate as a matrix for supporting thermochromic phase-change material. Background The solar heat utilization process is affected by weather and the like, and has the problems of intermittence, fluctuation and low energy density. The phase change heat storage material has the advantages of large heat storage density, approximately constant temperature in the phase change process, good stability and the like. Based on the advantages, the phase change material is applied to the solar heat storage technology, solar energy can be stored in a heat energy form, and heat energy with continuous, stable and high energy density is output, so that the energy utilization efficiency can be effectively improved. The traditional phase-change heat storage introduces photo-thermal conversion nano particles into the phase-change material, so that the problems of high surface temperature, uneven temperature distribution and the like of the heat collection surface are caused. The thermochromic phase change material compounded by the color former, the color developer and the phase change solvent can respond to temperature change and adjust dynamic cooperative conversion of light and heat, wherein a dark color system is displayed at low temperature, the light absorption capacity is high, a transparent colorless system is displayed at high temperature, and the light transmission capacity is high. Based on the advantages, the thermochromic phase-change material can ensure uniform internal temperature, reduce heat dissipation loss and improve energy utilization efficiency. Based on the phase transition characteristic of the solid-liquid phase change material, the solid-liquid phase change of the thermochromic phase change material can occur when the temperature reaches the phase change region of the solvent, and leakage occurs. In order to solve the problems, the thermochromic phase-change materials are encapsulated by high molecular polymer melamine formaldehyde resin (MF), polymethyl methacrylate (PMMA) and Polystyrene (PS) which are prepared by a physical-chemical method. However, the high molecular polymer has high requirements on polymerization conditions and raw materials, and has the problems of high toxicity, low degradability, raw material residues and the like, so that the application of the thermochromic phase change capsule is severely limited. Therefore, natural biopolymer alginate is selected as a matrix material, and the core material and Ca 2+ in a calcium chloride solution are subjected to ion exchange reaction by a instillation method to prepare the reversible thermochromic phase-change capsule coated with calcium alginate. Disclosure of Invention The invention aims to solve the problems in the prior art and provides a reversible thermochromic phase-change capsule heat storage material and a preparation method thereof. The reversible thermochromic phase change capsule is composed of an alginate serving as a matrix supporting thermochromic phase change material and a transparent calcium alginate shell material coating, wherein calcium alginate formed by ion exchange reaction between the alginate at the outer interface and Ca 2+ in a calcium chloride (CaCl 2) solution is used as a core material coating the transparent shell material through the alginate/thermochromic phase change material co-emulsion serving as the core material. The technical scheme adopted by the invention for solving the technical problems is that the reversible thermochromic phase-change capsule heat storage material comprises thermochromic phase-change material, 1-2.5% of alginate solution, nonionic surfactant and more than 20% of calcium chloride solution. Further, the composition of the thermochromic phase-change material is 1.56% of 3, 3-bis (4-dimethylaminophenyl) -6-dimethylaminobenzene peptide (CVL), a color former to determine color, 4.69% of 2, 2-bis (4-hydroxyphenyl) propane (BPA), a color former to determine color shade, 93.75% of tetradecyl alcohol (TD), a solvent to determine color-changing temperature range. Further, sodium alginate in the alginate is selected to prepare an alginate solution with the mass fraction of 1% -2.5%, and polysorbate-80 in the polysorbate is used as a surfactant. The thermochromic phase-change emulsion based on sodium alginate is formed by emulsifying the polysorbate-80 and the thermochromic phase-change material, and is used as a core material of the thermochromic phase-change capsule. Meanwhile, the sodium alginate and Ca 2+ in the calcium chloride solution are subjected to ion exchange reaction to generate calcium alginate