Method for preparing low-molecular polymer phase change material by emulsion method

Abstract

The invention focuses on the technical field of phase change material preparation, and provides a method for preparing a viscous polymer phase change material by adopting an emulsion method. The method comprises the following steps: firstly, in an emulsion polymerization reaction system, carrying out polymerization reaction on a phase change monomer with reaction activity and a cross-linking agent (co-emulsifier) under the initiation action of an initiator; the key innovation of the invention lies in that the emulsion method is used for replacing the traditional solution method to prepare the solid-solid phase change material, and the molecular weight of the polymer material is reduced, so that the flexibility of the side chain phase change material is remarkably improved, and the enthalpy value is further effectively increased. Meanwhile, the cooled phase-change material can form an independent granular structure, and the accumulation and caking phenomena possibly occurring in the process of preparing the polymer phase-change material in batches by a solution method are effectively avoided, so that the subsequent phase-change material processing procedure is remarkably simplified, the production cost is effectively reduced, the production efficiency is improved, and the method is suitable for industrial production. And the requirements of commercial production can be better met.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change material preparation, and more specifically, to a preparation method of a low molecular weight polymer phase change material by an emulsion method. Background Art

[0002] Composite phase change materials play a crucial role in the field of thermal management technology due to their excellent flexibility. They can absorb or release a large amount of latent heat within a specific temperature range, and thus are widely used in the thermal management technology requirements of various fields. After retrieval, a Chinese invention patent with the publication number CN116496763B discloses a composite phase change material, its preparation method, and a method for adjusting the phase change temperature of the phase change material. By adding a certain amount of ultra-high molecular weight polyethylene to the system of the phase change material, a synergistic effect can be generated with the supporting material of the composite phase change material, effectively adjusting the phase change temperature of the phase change material, improving the mechanical properties of the phase change temperature-regulating fiber, enabling the phase change temperature of the phase change material to meet the requirements of different application scenarios, saving the process of re-synthesizing or formulating the phase change material, and meeting the requirements of commercial production.

[0003] However, the viscous composite phase change material prepared by the physical coating process in this application is prone to generate a large amount of smoke during the melt blending process with polyester, which limits the application of this type of material in high-temperature scenarios.

[0004] To solve the above problems, a preparation method of a low molecular weight polymer phase change material by an emulsion method is proposed in this application. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a low molecular weight polymer phase change material by an emulsion method.

[0006] To solve the above technical problems, the present invention is realized through the following technical solutions: A preparation method of a low molecular weight polymer phase change material by an emulsion method includes the following steps; Emulsion method: A low molecular weight viscous phase change material is generated through emulsion polymerization reaction of a reactive phase change monomer and a crosslinking agent (co-emulsifier) under the action of an initiator. S1: Dissolve the emulsifier powder in water by low-speed stirring at 80°C to prepare a high-concentration emulsifier solution, and then dilute the emulsifier solution with water to form a uniform aqueous phase. S2: After the aqueous phase is formed, add the crosslinking agent (co-emulsifier) and the molecular weight adjustment auxiliary agent to the aqueous phase and emulsify to form a milky white foaming emulsion. S201: Add the flexible acrylate monomer and the reactive phase change monomer in a molten state to the aqueous phase and further emulsify to form an emulsion. S202: Add the initiator to the emulsion and stir evenly to obtain a homogeneous emulsion; S3: Subject the obtained emulsion to curing at 80 °C and low-temperature filtration and drying treatments to prepare a low-molecular-phase change material with adhesiveness; S4: The phase change material is formed and dispersed in water after the reaction, presenting a spherical viscous flow state, and forms a waxy spherical particle structure after cooling; The emulsifier is at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, poloxamer, polysorbate (Tween), lecithin, gelatin, gum arabic, sodium alginate, nanocellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, polyoxyethylene castor oil derivatives; The molecular weight regulating auxiliary agent is at least one of hydroquinone, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, benzoquinone, N-phenyl-α-naphthylamine, N,N'-di-sec-butyl-p-phenylenediamine, phosphate ester, borate ester, carbon tetrachloride, phosphorus pentachloride.

[0007] As a further preferred embodiment of the present invention, the emulsifier, water, flexible chain segment monomer, reactive phase change monomer, crosslinking agent (co-emulsifier), and initiator are in the following weight fractions: Emulsifier 0.1 - 0.5 parts, water 2 - 80 parts, flexible chain segment monomer 1 - 5 parts, reactive phase change monomer 15 - 16 parts, crosslinking agent (co-emulsifier) 0.02 - 0.04 parts, initiator 0.01 - 0.03 parts.

[0008] The reactive phase change monomer is at least one of polyethylene glycol, hexadecyl acrylate, octadecyl acrylate, methoxypolyethylene glycol, polyethylene glycol diacrylate, polyethylene glycol maleimide, polyethylene glycol succinimide carbonate, polyethylene glycol phospholipid, tetradecyl acrylate, eicosyl acrylate, docosyl acrylate, tetracosyl acrylate, polyethylene glycol acrylate; The crosslinking agent (co-emulsifier) is at least one of dipentaerythritol hexaacrylate, trimethylolpropane tris[3-(2-methylaziridinyl)propionate], pentaerythritol tetraacrylate, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, melamine formaldehyde resin, triallyl isocyanurate; Further preferably dipentaerythritol hexaacrylate, which provides more crosslinking sites, enables all monomers to react, and improves thermal stability; The initiator is at least one of azobisisobutyronitrile, azobis(2-methylpropionamidine) dihydrochloride, azodiisopropylimidazoline hydrochloride, benzoyl peroxide, di-tert-butyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, boron trifluoride, aluminum chloride, organotin, 2-hydroxy-2-methyl-1-phenyl-1-propanone, Irgacure 184, Irgacure 907.

[0009] As a further preferred embodiment of the present invention, in the step S1, the mass ratio range of the emulsifier to water is 1:100 - 5:100.

[0010] As a further preferred embodiment of the present invention, in the step S2, the emulsification condition is emulsifying at 6000 rpm for 5 minutes at 50°C.

[0011] As a further preferred embodiment of the present invention, in the step S201, the emulsification condition is emulsifying at 2000 rpm for 15 minutes at 50°C.

[0012] Advantages of the present invention: The present invention uses the emulsion method to replace the traditional solution method for preparing phase change materials, and dipentaerythritol hexaacrylate can provide more crosslinking sites, enabling all monomers to react, improving thermal stability, and thus avoiding the appearance of a large amount of smoke in high-temperature scenarios; in addition, the emulsion method can also prevent some monomers from not participating in the reaction due to excessive viscosity during the reaction process, improving the quality of the prepared phase change materials. The phase change material prepared by the emulsion method of the present invention has a low molecular weight of the polymer phase change material, large flexibility of the side-chain PCM, low phase change temperature and high enthalpy value. When preparing phase change materials in tons in batches, it forms a granular structure during cooling, avoiding the problem of difficult pulverization caused by large-area caking during cooling in the solution method for preparing phase change materials. Description of the drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0014] Figure 1 It is a schematic diagram of the finished product structure of the phase change material particles of the present invention; Figure 2 It is a schematic diagram showing the viscous properties of the phase change material of the present invention; Detailed implementation manners

[0015] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase. Example 1

[0016] (1) Add 2 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 8 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azodiisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the evenly mixed emulsion in step (4) in a heating environment at 80 °C, cure for 3 h, and then perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles. Example 2

[0017] (1) Add 3 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 7 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azodiisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the evenly mixed emulsion in step (4) in a heating environment at 80 °C, cure for 3 h, and then perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles. Example 3

[0018] (1) Add 4 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 6 parts of water to form a uniform aqueous phase; (2) Add 0.05 parts of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix well; (5) Place the emulsion mixed evenly in step (4) in a heating environment at 80 °C, carry out low-temperature filtration and drying treatment after curing for 3 h, and finally obtain sticky low-molecular polymer phase change material particles. Example 4

[0019] (1) Add 2 parts of an aqueous solution of 10% polyvinyl alcohol 1788 to 8 parts of water to form a uniform aqueous phase; (2) Add 0.1 part of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix well; (5) Place the emulsion mixed evenly in step (4) in a heating environment at 80 °C, carry out low-temperature filtration and drying treatment after curing for 3 h, and finally obtain sticky low-molecular polymer phase change material particles. Example 5

[0020] (1) Add 2 parts of an aqueous solution of 10% polyvinyl alcohol 1788 to 8 parts of water to form a uniform aqueous phase; (2) Add 0.15 parts of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix well; (5) Place the emulsion mixed evenly in step (4) in a heating environment at 80 °C, carry out low-temperature filtration and drying treatment after curing for 3 h, and finally obtain sticky low-molecular polymer phase change material particles. Example 6

[0021] (1) Add 4 parts of 10% polyvinyl alcohol 1788 aqueous solution to 16 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C, carry out low-temperature filtration and drying treatment after curing for 3 h, and finally obtain viscous low-molecular polymer phase change material particles. Example 7

[0022] (1) Add 3 parts of 10% polyvinyl alcohol 1788 aqueous solution to 12 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C, carry out low-temperature filtration and drying treatment after curing for 3 h, and finally obtain viscous low-molecular polymer phase change material particles. Example 8

[0023] (1) Add 2 parts of 10% polyvinyl alcohol 1788 aqueous solution to 8 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 1.5 parts of dodecyl acrylate and 14.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsions uniformly mixed in step (4) in a heating environment at 80 °C, and after curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain low-molecular polymer phase change material particles with adhesiveness. Example 9

[0024] (1) Add 2 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 8 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 0.5 part of dodecyl acrylate and 15.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of azodiisobutyramidine hydrochloride to the above emulsion and mix uniformly; (5) Place the emulsions uniformly mixed in step (4) in a heating environment at 80 °C, and after curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain low-molecular polymer phase change material particles with adhesiveness. Example 10

[0025] (1) Add 2 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 8 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 0.5 part of dodecyl acrylate and 15.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 part of Irgacure 184 to the above emulsion and mix uniformly; (5) Subject the emulsions uniformly mixed in step (4) to ultraviolet curing for 1 min, and then perform low-temperature filtration and drying treatment to finally obtain low-molecular polymer phase change material particles with adhesiveness.

[0026] Comparative Example 1 (1) Add 1 part of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 9 parts of water to form a uniform aqueous phase; (2) Add 0.05 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C. After curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles.

[0027] Comparative Example 2 (1) Add 2 parts of an aqueous solution of 10% polyvinyl alcohol 1799 to 8 parts of water to form a uniform aqueous phase; (2) Add 0.05 parts of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C. After curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles.

[0028] Comparative Example 3 (1) Add 5 parts of an aqueous solution of 10% polyvinyl alcohol 1799 to 5 parts of water to form a uniform aqueous phase; (2) Add 0.05 parts of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above emulsion, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 2.5 parts of dodecyl acrylate and 13.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a uniform emulsion; (4) Add 0.02 parts of azobisisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C. After curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles.

[0029] Comparative Example 4 (1) Add 2 parts of an aqueous solution of 10% polyvinyl alcohol 1788 to 8 parts of water to form a uniform aqueous phase; (2) Add 2 parts of dipentaerythritol hexaacrylate and 0.03 parts of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a uniform foaming emulsion; (3) Add 0.5 parts of dodecyl acrylate and 15.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a homogeneous emulsion; (4) Add 0.02 parts of azodiisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C. After curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles.

[0030] Comparative Example 5 (1) Add 2 parts of an aqueous solution of polyvinyl alcohol 1788 with a concentration of 10% to 8 parts of water to form a homogeneous aqueous phase; (2) Add 0.01 part of dipentaerythritol hexaacrylate and 0.03 part of hydroquinone to the above aqueous phase, and emulsify at 6000 rpm for 5 min to form a homogeneous foaming emulsion; (3) Add 0.5 parts of dodecyl acrylate and 15.14 parts of hexadecyl acrylate to the above emulsion, and emulsify at 2000 rpm for 15 min to form a homogeneous emulsion; (4) Add 0.02 parts of azodiisobutyramidine hydrochloride to the above emulsion and mix evenly; (5) Place the emulsion evenly mixed in step (4) in a heating environment at 80 °C. After curing for 3 h, perform low-temperature filtration and drying treatment to finally obtain sticky low-molecular polymer phase change material particles.

[0031] The test results of the sticky phase change materials obtained in the preparation processes of the above Examples 1-10 and Comparative Examples 1-5 at different proportion dosages are compared as follows: Case Enthalpy value (J / g) Melting point (°C) Description of thermal stability Example 1 91 24 Can be drawn into filaments above the melting point, has fluidity, and is smokeless at 280°C Example 2 88 23.05 Can be drawn into filaments above the melting point, has fluidity, and is smokeless at 280°C Example 3 86.529 22.69 Can be drawn into filaments above the melting point, has fluidity, and is smokeless at 280°C Example 4 86.322 24.54 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 5 77.608 25.7 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 6 85 25.94 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 7 89.29 25.58 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 8 98 28 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 9 99.965 27.75 Can be drawn into filaments above the melting point, and is smokeless at 280°C Example 10 97 28.03 Can be drawn into filaments above the melting point, and is smokeless at 280°C Comparative Example 1 - - Unable to form an emulsion Comparative Example 2 - - Unstable during the emulsion reaction Comparative Example 3 - - Unstable during the emulsion reaction Comparative Example 4 - - Cannot be drawn into filaments above the melting point Comparative Example 5 - - Smoky at 280°C It can be seen from the above test results that the present invention uses the emulsion method to replace the traditional solution method to prepare the phase change material, reducing the molecular weight of the polymer material, thereby increasing the flexibility of the side-chain phase change material and improving the enthalpy value. At the same time, this method can make the phase change material after cooling form an independent granular structure, effectively avoiding the stacking and caking phenomena that may occur in the process of batch preparation of polymer phase change materials by the solution method, saving the subsequent processing procedures of the phase change material, and meeting the requirements of commercial production.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a low-molecular polymer phase change material by an emulsion method, characterized in that, It includes the following steps; Emulsion method: Under the action of an initiator, a reactive phase change monomer and a crosslinking agent (co-emulsifier) are subjected to emulsion polymerization reaction to generate a low-molecular-weight viscous phase change material; S1: Stir the emulsifier powder at a low speed in water at 80 °C to dissolve it, prepare a high-concentration emulsifier solution, and then dilute the emulsifier solution with water to form a uniform aqueous phase; S2: After the aqueous phase is formed, add the crosslinking agent (co-emulsifier) and the molecular weight regulating auxiliary agent to the aqueous phase and emulsify to form a milky white foaming mixture; S201: Add the flexible chain segment monomer and the reactive phase change monomer in the molten state to the above mixture and further emulsify to form an emulsion; S202: Add the initiator to the emulsion and stir evenly to obtain a uniform emulsion; S3: Subject the obtained emulsion to high-temperature curing at 80 °C and low-temperature filtration and drying treatment at 20 °C to obtain a viscous low-molecular-weight phase change material; S4: The viscous phase change material forms spherical viscous fluids dispersed in water after the reaction and forms a waxy spherical particle structure from the viscous flow state after cooling; The emulsifier is at least one of sodium dodecyl sulfate, poloxamer, polysorbate (Tween), lecithin, gelatin, gum arabic, sodium alginate, nanocellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, polyoxyethylene castor oil derivative; The molecular weight regulating and inhibiting auxiliary agent is at least one of hydroquinone, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, benzoquinone, N-phenyl-α-naphthylamine, N,N'-di-sec-butyl-p-phenylenediamine, phosphate ester, borate ester, carbon tetrachloride, phosphorus pentachloride; 2. The preparation method of the low molecular polymer phase change material by the emulsion method according to claim 1, characterized in that: The weight fractions of the emulsifier, water, flexible chain segment monomer, reactive phase change monomer, crosslinking agent (co-emulsifier), and initiator are as follows: Emulsifier 0.1 - 0.5 parts, water 2 - 80 parts, flexible chain segment monomer 1 - 5 parts, reactive phase change monomer 10 - 16 parts, crosslinking agent (co-emulsifier) 0.02 - 0.04 parts, initiator 0.01 - 0.03 parts.

3. The preparation method of the low-molecular polymer phase change material by the emulsion method according to claim 1, characterized in that: In the step S1, the mass ratio range of the emulsifier to water is 1:100 - 5:

100.

4. The preparation method of the emulsion low molecular polymer phase change material according to claim 3, characterized in that: For the prepared aqueous emulsifier solution, the preferred mass ratio of the emulsifier to water is 1:

10.

5. The preparation method of the low-molecular polymer phase change material by the emulsion method according to claim 1, characterized in that: In the step S2, the emulsification condition is emulsifying at 6000 rpm for 5 minutes at 50 °C.

6. The preparation method of the emulsion method low molecular weight viscous polymer phase change material according to claim 1, characterized in that: The crosslinking agent (co-emulsifier) in the step S2 can provide multiple crosslinking sites to make all monomers react, including at least one of dipentaerythritol hexaacrylate, trimethylolpropane tris[3-(2-methylaziridinyl)propionate], pentaerythritol tetraacrylate, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, melamine formaldehyde resin, triallyl isocyanurate; 7. The preparation method of the emulsion low molecular viscous polymer phase change material according to claim 1, characterized in that: The reactive phase change monomer in the step S201 is at least one of polyethylene glycol, hexadecyl acrylate, octadecyl acrylate, methoxypolyethylene glycol, polyethylene glycol diacrylate, polyethylene glycol maleimide, polyethylene glycol succinimide carbonate, polyethylene glycol phospholipid, tetradecyl acrylate, eicosyl acrylate, docosyl acrylate, tetracosyl acrylate, polyethylene glycol acrylate; 8. The preparation method of the low molecular weight polymer phase change material by the emulsion method according to claim 1, characterized in that: In the step S201, the emulsification condition is emulsifying at 2000 rpm for 15 minutes at 50 °C.

9. The preparation method of the emulsion method low molecular weight polymer phase change material according to claim 1, characterized in that: In the step S202, the initiator is at least one of azobisisobutyronitrile, azobis(isobutyramidine) hydrochloride, azodiisopropylimidazoline hydrochloride, benzoyl peroxide, di-tert-butyl peroxide, potassium persulfate, sodium persulfate, ammonium persulfate, boron trifluoride, aluminum chloride, organotin, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Irgacure 184, and Irgacure 907.

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