Copolymerized hydrogel-sodium acetate trihydrate composite phase change material, preparation method and application thereof

Abstract

The invention relates to a copolymerized hydrogel-sodium acetate trihydrate composite phase change material as well as a preparation method and application thereof, and belongs to the technical field. The copolymerized hydrogel is prepared from the following components in parts by mass: 3-10 parts of a copolymerized hydrogel base material, 87-97 parts of sodium acetate trihydrate and 0.5-3 parts of a nucleating agent, the copolymerized hydrogel base material is prepared from two polymer monomers, a cross-linking agent, an initiator and a photo-thermal agent, wherein one polymer monomer is acrylamide; the nucleating agent is sodium carbonate decahydrate. High loading rate and high phase change latent heat value of the sodium acetate trihydrate phase change material are realized by utilizing the copolymerized hydrogel under the condition of a specific nucleating agent. The material is in a solid state all the time before and after phase change, and the problems of supercooling, phase separation and easy leakage of sodium acetate trihydrate do not exist.

Description

Technical Field

[0001] The invention relates to a copolymer hydrogel-sodium acetate trihydrate composite phase change material, a preparation method and application thereof, and belongs to the technical field. Background Art

[0002] In the field of renewable energy, thermal energy storage technology plays an important role in solar thermal utilization and building energy conservation as a key means to improve energy efficiency. Phase change thermal storage materials (PCM) have attracted widespread attention due to their unique properties, namely storing or releasing a large amount of heat within a specific temperature range. By selecting suitable phase change materials, a large amount of thermal energy can be efficiently stored in a small volume, thereby effectively balancing the difference in energy supply and demand and improving the overall performance of the system.

[0003] At present, the phase change heat storage materials available on the market are mainly divided into two categories: organic and inorganic hydrated salts. Organic materials such as high molecular copolymers such as paraffin have the advantages of zero supercooling, no phase separation, low corrosiveness and easy processing, but their own high price, low thermal conductivity and flammability and other disadvantages limit their large-scale application. Among inorganic materials, inorganic hydrated salts, as an extremely important type of phase change material, have been widely used in the industry because of their high latent heat value, good chemical stability and low cost. Among them, the melting point of the inorganic hydrated salt sodium acetate trihydrate is about 58 ° C, with a high latent heat value (about 250-280 kJ / kg). As an inorganic compound, sodium acetate trihydrate is friendly to the human body and the environment, and has abundant raw material sources, mature production technology, relatively low cost, easy to achieve large-scale production and application, and is very suitable for medium and low temperature thermal energy storage, such as solar thermal storage systems, building energy saving and other scenarios. However, in order to avoid leakage of sodium acetate trihydrate in a liquid state, a composite phase change material must be prepared and packaged and shaped.

[0004] Currently, the commonly used method for shaping sodium acetate trihydrate is mainly to use porous substrates for adsorption and encapsulation. However, the composite phase change materials prepared using porous materials as carriers usually show problems of lower mechanical strength and increased brittleness, which not only limits the application range of the material, but also may shorten its actual service life.

[0005] In order to solve the problems of unstable loading rate and poor mechanical properties caused by the adsorption and encapsulation of sodium acetate trihydrate on porous substrates, people have tried to encapsulate sodium acetate trihydrate through a three-dimensional network structure rich in hydrogels. Most of the current research reports are single hydrogel network structure encapsulation. Yizhe Liu (J. Mater. Chem. A, 2024, 12, 31982–31992) used acrylamide (AM) in situ polymerization in the molten state of sodium acetate trihydrate to prepare a composite phase change material with a cross-linked three-dimensional PAM network, but the maximum loading rate without leakage was only 80%, resulting in an enthalpy value of the composite phase change material of only 180 J / g; Minyu Song (Chemical Engineering Journal 464 (2023) 142682) also used acrylamide as a polymerization monomer and carried out in situ polymerization in a molten sodium acetate trihydrate (SAT) solution to prepare a composite phase change material. Konjac glucomannan was used as a supporting material, which not only improved the loading efficiency of SAT, but also effectively reduced the supercooling phenomenon of sodium acetate trihydrate. The experimental results show that the maximum loading of SAT reaches 90.4% and the enthalpy value is 217.2 J / g. However, as the loading rate increases, the composite material exhibits significant leakage problems. Patent application CN116656071A discloses a thermally conductive phase change hydrogel and a preparation method thereof. The phase change hydrogel is prepared by in-situ polymerization, but 40-95% of water is additionally introduced during the preparation process to reduce the melting temperature of the phase change material, thereby reducing the reaction temperature of the system and performing polymerization reaction at 35-40°C; Patent application CN113402669A discloses a self-healing hydrogel phase change material and a preparation method thereof. The hydrogel phase change material is also prepared by in-situ polymerization, but 10% of the mass of the phase change material is additionally introduced during the preparation process to reduce the melting temperature of the solution, so that the reaction temperature of the system can be controlled at 40-60°C. The performance of polyacrylamide is relatively stable below 70°C, but when the temperature rises, the thermal motion of the polyacrylamide molecular chain intensifies, which will have a negative impact on the ability of the polyacrylamide network to load the phase change material. This shows that the simple polyacrylamide network is well compatible with sodium acetate trihydrate, but the single polymer network has limitations in its carrying capacity and temperature tolerance for salt substances. Summary of the invention

[0006] In view of this, the object of the present invention is to provide a copolymer hydrogel-sodium acetate trihydrate composite phase change material, a preparation method and its application. The present invention adopts copolymer hydrogel as the encapsulation matrix material to achieve a high load on sodium acetate trihydrate, thereby ensuring a high utilization rate of phase change latent heat. In addition, the composite material also has excellent mechanical strength, salt resistance and thermal stability, can maintain structural integrity in a high temperature and high salt environment, effectively prevent leakage of phase change materials, ensure long-term stable operation, and significantly improve the performance and reliability of the entire phase change energy storage system.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows.

[0008] A copolymer hydrogel-sodium acetate trihydrate composite phase change material is prepared from the following components by weight: 3 to 10 parts of copolymer hydrogel substrate, 87 to 97 parts of sodium acetate trihydrate, and 0.5 to 3 parts of nucleating agent;

[0009] The raw material composition of the copolymer hydrogel substrate includes two polymer monomers, a cross-linking agent, an initiator and a photothermal agent, wherein one of the polymer monomers is acrylamide (AM);

[0010] The nucleating agent is sodium carbonate decahydrate (SCD).

[0011] Preferably, the mass fraction of the nucleating agent is 1 to 2 parts.

[0012] Preferably, the usage ratio of the two polymer monomers, the crosslinking agent, the initiator and the photothermal agent is 0.4-1g:5-20mg:2-20mg:5-30mg; more preferably, the usage ratio of the two polymer monomers, the crosslinking agent, the initiator and the photothermal agent is 0.4-1g:10-15mg:10-15mg:10-20mg.

[0013] Preferably, the other polymer monomer of the two polymer monomers is 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acrylic acid (AA), methacrylic acid (MAA), N-hydroxymethyl acrylamide (NMA), N-isopropyl acrylamide (NIPAM) or N-vinyl pyrrolidone (NVP).

[0014] Preferably, the molar ratio of acrylamide to another polymer monomer is 3:1 to 19:1.

[0015] Preferably, the cross-linking agent is N,N-methylenebisacrylamide (BIS).

[0016] Preferably, the initiator is ammonium persulfate (APS) or potassium persulfate (KPS).

[0017] Preferably, the photothermal agent is expanded graphite (EG) or water-soluble carbon black (Cb).

[0018] Preferably, the phase change temperature of the composite phase change material is 50°C to 60°C (more preferably 54°C to 58°C), the phase change latent heat is 200 J / g to 270 J / g, and the photothermal conversion efficiency is above 80%.

[0019] A method for preparing the copolymer hydrogel-sodium acetate trihydrate composite phase change material of the present invention comprises the following steps:

[0020] After sodium acetate trihydrate is heated and stirred to dissolve at 70°C to 90°C, two polymer monomers, a crosslinker, a photothermal agent and a nucleating agent are added, and the heating and stirring are continued for 15min to 30min. Then, an initiator is added, and the heating and stirring are continued for 5s to 30s. The mixture is transferred to a mold and reacted at 70°C to 90°C for 1h to 3h to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change material.

[0021] Beneficial Effects

[0022] (1) The present invention provides a copolymer hydrogel-sodium acetate trihydrate composite phase change material, which uses copolymer hydrogel to achieve a high loading rate and high phase change latent heat value of sodium acetate trihydrate phase change material under a specific nucleating agent. Furthermore, the phase change temperature of the solid phase change energy storage material is 54-58°C, the phase change latent heat is 200J / g-270J / g, and the light-to-heat conversion efficiency is above 80%.

[0023] (2) The present invention provides a copolymer hydrogel-sodium acetate trihydrate composite phase change material, which is always in a solid state before and after the phase change, does not have the problems of sodium acetate trihydrate supercooling, phase separation and easy leakage, and can be prepared into different shapes according to needs.

[0024] (3) The present invention provides a method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change material. The preparation process is always maintained at 70-90° C., effectively achieving the encapsulation of sodium acetate trihydrate by the copolymer hydrogel.

[0025] (4) The copolymer hydrogel-sodium acetate trihydrate composite phase change material of the present invention can be reused, and the latent heat of phase change is small after repeated use, and the service life is long; the material is non-toxic and pollution-free, safe and environmentally friendly, and is a non-hazardous product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the freezing Tt curve of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1 of the present invention.

[0027] Figure 2 This is the DSC curve of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1 of the present invention.

[0028] Figure 3This is the DSC curve of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 2 of the present invention.

[0029] Figure 4 This is a photothermal conversion effect diagram of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1 of the present invention.

[0030] Figure 5 This is the DSC curve of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1 of the present invention after 200 cycles. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with specific embodiments.

[0032] Example 1

[0033] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0034] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0035] (2) Accurately weigh 0.32 g AM, 0.08 g AMPS, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0036] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90°C oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material that can perform photothermal energy storage.

[0037] The prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material is in a soft black opaque solid state in a molten state and in a hard black opaque solid state in a crystallized state.

[0038] The freezing Tt curve of the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material is as follows Figure 1 As shown, the DSC curve is Figure 2 As shown. After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material capable of photothermal energy storage has a phase change latent heat of 261.5 J / g and a phase change temperature of 55.6°C.

[0039] Example 2

[0040] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0041] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 70° C. until it becomes a solution;

[0042] (2) Accurately weigh 0.32 g AM, 0.08 g AMPS, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 70 °C water bath for 30 min;

[0043] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 70° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0044] The DSC curve of the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material is as follows: Figure 3 The test shows that the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 254.7 J / g and a phase change temperature of 55.4°C.

[0045] Example 3

[0046] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0047] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0048] (2) Accurately weigh 0.8 g AM, 0.2 g AMPS, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0049] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0050] After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 239 J / g and a phase change temperature of 55.2°C.

[0051] Example 4

[0052] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0053] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0054] (2) Accurately weigh 0.32 g AM, 0.08 g NVP, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0055] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0056] After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 252.9 J / g and a phase change temperature of 56.0°C.

[0057] Example 5

[0058] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0059] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0060] (2) Accurately weigh 0.24 g AM, 0.16 g NVP, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0061] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0062] After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 246.7 J / g and a phase change temperature of 55.3°C.

[0063] Example 6

[0064] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0065] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0066] (2) Accurately weigh 0.32 g AM, 0.08 g MAA, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0067] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0068] After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 251.8 J / g and a phase change temperature of 56.3°C.

[0069] Example 7

[0070] A method for preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material, the method steps comprising:

[0071] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0072] (2) Accurately weigh 0.32 g AM, 0.08 g AMPS, 0.002 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0073] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0074] After testing, the prepared copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a phase change latent heat of 256.2 J / g and a phase change temperature of 55.9°C.

[0075] Verification of the cyclic stability of copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material:

[0076] (1) preparing a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material according to the preparation method of the present invention, and making the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material of the present invention into a 20×20×3 mm rectangular composite phase change material;

[0077] (2) The rectangular composite phase change material is placed in a high and low temperature humidity test chamber, and a cyclic heating and cooling program is set to simulate the recycling process of the phase change material.

[0078] Figure 4 This is the DSC curve of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1 after 200 cycles. The test shows that the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material has a small phase change latent heat attenuation after repeated use. The results of Examples 2-7 are similar to those of Example 1.

[0079] Verification of photothermal conversion of copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material capable of photothermal energy storage:

[0080] (1) According to the preparation method of the present invention, a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material capable of photothermal energy storage is prepared, and the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material capable of photothermal energy storage of the present invention is made into a 100×2 mm cylindrical composite phase change energy storage material;

[0081] (2) The cylindrical composite phase change energy storage material was placed under a solar simulator, and the light intensity was set to 1 kW / m 2 and 2kW / m 2 , detect its temperature change.

[0082] Figure 5 This is a photothermal conversion effect diagram of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained in Example 1. According to the test, the photothermal conversion efficiency of the copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material obtained is above 80%. The results of Examples 2-7 are similar to those of Example 1.

[0083] Comparative Example 1

[0084] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0085] (2) Accurately weigh 0.4 g AM, 0.01 g BIS, and 0.1 g SCD, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0086] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0087] After leakage testing of the prepared samples, it was found that the obtained copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material did not achieve effective coating of sodium acetate trihydrate.

[0088] Comparative Example 2

[0089] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0090] (2) Accurately weigh 0.32 g AA, 0.08 g AMPS, 0.01 g BIS, 0.1 g SCD, and 0.015 g Cb, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0091] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90° C. oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material.

[0092] After leakage testing of the prepared samples, it was found that the obtained copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material did not achieve effective coating of sodium acetate trihydrate.

[0093] Comparative Example 3

[0094] (1) Accurately weigh 10 g of sodium acetate trihydrate, add it into a glass container, and heat and stir at 90° C. until it becomes a solution;

[0095] (2) Accurately weigh 0.32 g NIPAM, 0.08 g AMPS, 0.01 g BIS, and 0.1 g SCD, add them into a glass container, and stir in a 90 °C water bath for 30 min;

[0096] (3) Accurately weigh 0.005 g of APS and add it to a glass container, then place the glass bottle in a 90°C oven for 2 hours to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material that can perform photothermal energy storage.

[0097] After leakage testing of the prepared samples, it was found that the obtained copolymer hydrogel-sodium acetate trihydrate composite phase change energy storage material did not achieve effective coating of sodium acetate trihydrate.

[0098] In summary, the invention includes but is not limited to the above embodiments. Any equivalent substitution or partial improvement made under the spirit and principle of the invention shall be deemed to be within the protection scope of the invention.

Claims

1. A copolymer hydrogel-sodium acetate trihydrate composite phase change material, characterized in that: The preparation method is prepared from the following components by weight: 3-10 parts of copolymer hydrogel substrate, 87-97 parts of sodium acetate trihydrate, and 0.5-3 parts of nucleating agent; The raw material composition of the copolymer hydrogel substrate includes two polymer monomers, a crosslinking agent, an initiator and a photothermal agent, wherein one of the polymer monomers is acrylamide; The nucleating agent is sodium carbonate decahydrate.

2. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to claim 1, characterized in that: The mass fraction of the nucleating agent is 1 to 2 parts.

3. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to claim 1, characterized in that: The usage ratio of the two polymer monomers, the crosslinking agent, the initiator and the photothermal agent is 0.4-1g: 5-20mg: 2-20mg: 0-30mg; more preferably, the usage ratio of the two polymer monomers, the crosslinking agent, the initiator and the photothermal agent is 0.4-1g: 10-15mg: 10-15mg: 10-20mg.

4. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to claim 1, characterized in that: The other polymer monomer of the two polymer monomers is 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, methacrylic acid, N-hydroxymethyl acrylamide, N-isopropyl acrylamide or N-vinyl pyrrolidone.

5. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to claim 1, characterized in that: The molar ratio of the acrylamide to another polymer monomer is 3:1 to 19:

1.

6. A copolymer hydrogel-sodium acetate trihydrate composite phase change material according to any one of claims 1 to 5, characterized in that: The cross-linking agent is N,N-methylenebisacrylamide.

7. A copolymer hydrogel-sodium acetate trihydrate composite phase change material according to any one of claims 1 to 5, characterized in that: The initiator is ammonium persulfate or potassium persulfate.

8. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to any one of claims 1 to 5, characterized in that: The photothermal agent is expanded graphite or water-soluble carbon black.

9. The copolymer hydrogel-sodium acetate trihydrate composite phase change material according to claim 1, characterized in that: The phase change temperature of the composite phase change material is 50° C. to 60° C., the phase change latent heat is 200 J / g to 270 J / g, and the light-to-heat conversion efficiency is above 80%.

10. A method for preparing the copolymer hydrogel-sodium acetate trihydrate composite phase change material according to any one of claims 1 to 9, characterized in that: The method steps include: After sodium acetate trihydrate is heated and stirred to dissolve at 70°C to 90°C, two polymer monomers, a crosslinker, a photothermal agent and a nucleating agent are added, and the heating and stirring are continued for 15min to 30min. Then, an initiator is added, and the heating and stirring are continued for 5s to 30s. The mixture is transferred to a mold and reacted at 70°C to 90°C for 1h to 3h to obtain a copolymer hydrogel-sodium acetate trihydrate composite phase change material.

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