Radiation and phase change coupled thermal management composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of radiation refrigeration, and discloses a radiation and phase change coupled thermal management composite material and a preparation method and application thereof, and the radiation and phase change coupled thermal management composite material comprises a radiation refrigeration material part of a porous structure, and the lower half pore channel and / or the surface of the radiation refrigeration material part are / is filled with a phase change material. The preparation method comprises the following steps: taking an oily compound, an initiator, an emulsifier and a water phase as raw materials to prepare a high internal phase emulsion; carrying out emulsion polymerization on the high internal phase emulsion to obtain porous foam; performing strong emission modification on the porous foam; and placing the strong emission modified porous foam in a molten phase change material, so that the molten phase change material is adsorbed in part of pore channels and / or on the surface of the strong emission modified porous foam. The composite material has high heat storage performance, reflectivity and high emissivity, the radiation refrigeration part and the phase change heat management material are firmly combined, layering and cracking are avoided, and the mechanical stability is high.

Description

Technical Field

[0001] This invention belongs to the field of radiation refrigeration technology, specifically relating to a thermal management composite material coupled with radiation and phase change, its preparation method, and its application. Background Technology

[0002] The energy crisis and global warming are increasingly becoming major obstacles to sustainable development. Currently, buildings account for over 40% of global energy consumption to maintain comfortable indoor temperatures, and cooling demand is projected to triple by 2050. Against this backdrop, there is an urgent need to explore breakthrough solutions to alleviate energy shortages and address global warming. Among numerous technological approaches, passive radiative cooling (RC) stands out as a revolutionary, zero-emission, green cooling technology that utilizes specific wavelengths of thermal radiation to guide heat directly into outer space through atmospheric windows (8–13 μm), while simultaneously strongly reflecting solar radiation (0.3–3 μm), demonstrating unique environmental advantages. Although many studies have confirmed RC's suitability as an energy-efficient cooling technology for buildings, unfortunately, the cooling power of most existing RC materials / equipment is generally below 150 W / m². 2 However, people's actual cooling needs during the day are far higher than this value, and existing RC systems are unable to meet the actual application requirements.

[0003] Existing research indicates that combining RC (Radiative Reduction) with phase change thermal management technology is an effective strategy for improving cooling power. In realizing this invention, the inventors discovered at least the following problems in the prior art: Composite materials containing a phase change material layer and a radiative cooling layer are obtained through mechanical stacking. These composite materials lack a systematic integrated design, and relying on fragmented combinations cannot achieve the integration and synergistic effect of RC and the phase change material. Furthermore, they often suffer from cumbersome preparation processes and low long-term service reliability in practical applications. Patent application CN 120098306 A discloses a method for preparing a flexible material with dual functions of radiative cooling and photothermal conversion storage. This application prepares a flexible phase change material matrix by mixing n-octadecane, SEBS, and POE and hot-pressing the mixture. A barium sulfate acrylic resin emulsion is sprayed onto one side of the flexible phase change material matrix, and an MXene solution is sprayed onto the other side of the flexible phase change material to obtain a flexible material with dual functions of radiative cooling and photothermal conversion storage. This solution aims to improve the enthalpy and energy storage performance of existing RC (Refrigerant Controller) phase change materials (RCs) based on a barium sulfate radiation cooling layer, an MXene selective absorption coating, and a flexible phase change material substrate. However, this solution suffers from numerous raw material requirements, complex technology, difficulties in effectively combining the MXene selective absorption coating and the barium sulfate radiation cooling layer, and high controllability in preparation. Patent application CN118978743 discloses a method for preparing a flexible radiation cooling phase change material, which involves mixing a polyvinyl alcohol aqueous solution with metal oxide particles, freeze-drying to obtain a flexible carrier, and then impregnating the phase change material into the flexible carrier to obtain the flexible radiation cooling phase change material. This material suffers from low enthalpy and emissivity. Providing a high-performance radiation cooling material that can organically combine RC with other thermal management materials represents a key breakthrough in solving zero-energy building cooling and is a strategic direction for addressing the current dual crises of energy and environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a thermal management composite material coupled with radiation and phase change, its preparation method and application, in order to address the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, a thermal management composite material coupled with radiation and phase change is provided, including a radiation cooling material part, the radiation cooling material part having a porous structure, and the lower half of the radiation cooling material part having pores and / or surface filled with a phase change material.

[0007] On the other hand, a method for preparing a radiation- and phase-change coupled thermal management composite material is provided, comprising:

[0008] A high internal phase emulsion was prepared by using oily compounds, initiators, emulsifiers and aqueous phase as raw materials;

[0009] The high internal phase emulsion was emulsion polymerized to obtain porous foam;

[0010] The porous foam is subjected to strong emission modification;

[0011] The highly emissive modified porous foam is placed in a molten phase change material, so that the molten phase change material is partially adsorbed into the pores and / or surface of the highly emissive modified porous foam.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] 1. This invention provides a radiation-phase change coupled thermal management composite material, comprising a porous radiative cooling material portion and a phase change material filling the lower half of the pores and / or surface of the radiative cooling material portion. This radiation-phase change coupled thermal management composite material has high heat storage performance, reflectivity, and high emissivity. The latent heat of phase change is about 200 J / g, and the reflectivity can reach up to 98.2%, which can effectively reflect sunlight. It has high emissivity in the infrared window region, especially in the atmospheric window, with an emissivity of up to 98.3%, and has a significantly improved radiative cooling effect.

[0014] 2. This invention provides a method for preparing a thermal management composite material coupled with radiation and phase change, which is obtained by adsorbing a portion of the molten phase change material into a porous material after introducing strong emitting groups. The radiation cooling part and the phase change thermal management material are firmly bonded, without delamination or cracking, and have high mechanical stability.

[0015] 3. Preferably, the method for preparing the radiation- and phase change coupled thermal management composite material of the present invention achieves controllable adsorption of phase change material on radiation-cooling material, thereby obtaining a phase change material with higher structural stability and enthalpy value.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 Photograph 'a' is a morphology image of the high internal phase emulsion from step (2) of Example 1. Figure 1 b is a photograph of the morphology of the porous foam in step (3) of Example 1;

[0018] Figure 2 The image shows a scanning electron microscope (SEM) image of the porous foam cross-section in step (3) of Example 1.

[0019] Figure 3 This is a schematic diagram showing the test results of the reflectivity of the thermal management composite material coupled with radiation and phase change in Example 1;

[0020] Figure 4 This is a schematic diagram showing the emissivity test results of the composite material prepared in Example 2;

[0021] Figure 5 This is a morphology diagram of the adsorbed molten docosane in step (5) of Example 1. Detailed Implementation

[0022] The technical solution will now be clearly and completely described with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] In the following description, the term "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. A and B can be singular or plural.

[0024] In the following description, the terms “including,” “containing,” “having,” and “containing” are open-ended terms, meaning that they include but are not limited to.

[0025] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0026] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] The technical principle adopted in this invention is as follows: by setting a phase change material in the lower part of the radiative cooling material with high cooling power, the radiative cooling characteristics of the radiative cooling material and the phase change temperature control characteristics of the phase change material are fully combined to obtain an integrated thermal management composite material that couples radiation and phase change. This composite material has significantly improved latent heat of phase change, reflectivity and emissivity.

[0029] On the one hand, a thermal management composite material coupled with radiation and phase change is provided, including a radiation cooling material part, the radiation cooling material part having a porous structure, and the lower half of the radiation cooling material part having pores and / or surface filled with a phase change material.

[0030] In some embodiments, the ratio of the height of the radiative cooling material section filled with phase change material to the total height of the radiative cooling material section is ≤80%. Preferably, the height of the radiative cooling material section filled with phase change material accounts for 30% to 70% of the total height of the radiative cooling material section.

[0031] On the one hand, a method for preparing a radiation- and phase-change coupled thermal management composite material is provided, comprising:

[0032] A high internal phase emulsion was prepared by using oily compounds, initiators, emulsifiers and aqueous phase as raw materials;

[0033] The high internal phase emulsion was emulsion polymerized to obtain porous foam;

[0034] The porous foam is subjected to strong emission modification;

[0035] The high-emission modified porous foam is placed in a molten phase change material, so that the molten phase change material is adsorbed into part of the pores and / or the surface of the high-emission modified porous foam.

[0036] This invention first prepares porous foam, then modifies it with strong emission, and then allows the modified porous foam to adsorb molten phase change material, resulting in a thermal management composite material that couples radiation and phase change. The phase change material and the radiation cooling material can be effectively combined, and the resulting composite material has high reflectivity and emissivity. The method of this invention realizes the integrated preparation of radiation cooling material and phase change material.

[0037] Furthermore, the preparation of porous materials involves first preparing a high internal phase emulsion, and then subjecting it to emulsion polymerization to obtain porous materials. A high internal phase emulsion refers to an emulsion with an internal phase volume fraction of more than 74%. In this invention, an oily compound is used as the continuous phase and an aqueous phase is used as the dispersed phase (internal phase) to form a water-in-oil high internal phase emulsion. Under the action of an initiator, the oily compound is polymerized by radiation initiation to form a porous material. The preparation process is green and environmentally friendly, and the obtained porous foam has a high porosity.

[0038] In some embodiments, the oily compound includes one or more of styrene, divinylbenzene (DVB), methyl methacrylate, butyl acrylate, acrylonitrile, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate. In some preferred embodiments, the oily compound is divinylbenzene, or a mixture of divinylbenzene and styrene, or a mixture of divinylbenzene and butyl acrylate; more preferably, the oily compound is divinylbenzene.

[0039] The preferred oily compound of the present invention is divinylbenzene, or a mixture of divinylbenzene and component A, wherein component A is styrene or butyl acrylate. In the mixture system of divinylbenzene and component A, divinylbenzene acts as a crosslinking agent during the polymerization process to promote the polymerization of raw materials to form a porous material.

[0040] In some embodiments, the initiator includes one or more of benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile (AIBN), azobisisoheptanenitrile, azobisisopropylimidazolium hydrochloride, potassium persulfate, ammonium persulfate, α-ketoglutarate, tert-butyl hydroperoxide, and iron-based initiators; in some preferred embodiments, the initiator is azobisisobutyronitrile, or tert-butyl hydroperoxide and an iron-based initiator, wherein the iron-based initiator is a soluble ferrous salt. The addition of an initiator can initiate and promote the polymerization of oily compounds.

[0041] In some embodiments, the emulsifier includes one or more of the following: Span series emulsifiers, polyglycerol fatty acid esters, polyoxyethylene ethers, modified oil ethoxylates, fatty acid salts, and diglycerides; preferably, the emulsifier is a Span series emulsifier and / or a polyoxyethylene ether. A preferred emulsifier is a surfactant with a low HLB value to stabilize the oil phase in a high internal phase emulsion. More preferably, the emulsifier is Span 80.

[0042] In some embodiments, the mass ratio of the oily compound to the emulsifier is 1:(0.1~0.4), and more preferably, the mass ratio of the oily compound to the emulsifier is 1:(0.2~0.4).

[0043] In some embodiments, the mass ratio of the oily compound to the initiator is 1:(0.01~0.1). In some preferred embodiments, the mass ratio of the oily compound to the initiator is 1:(0.01~0.02).

[0044] In some embodiments, the mass ratio of the oily compound to the aqueous phase is 1:(1~20). In some preferred embodiments, the mass ratio of the oily compound to the aqueous phase is 1:(5~10).

[0045] In some embodiments, the emulsion polymerization temperature is 0–90 °C, and the emulsion polymerization time is 0.1–24 h; in some preferred embodiments, the emulsion polymerization temperature is 20–80 °C. In some embodiments, the process further includes removing the aqueous phase from the system after polymerization to obtain porous foam; the method for removing the aqueous phase may be natural evaporation, drying, or freeze-drying.

[0046] In some embodiments, the preparation of a high internal phase emulsion using an oily compound, an initiator, an emulsifier, and an aqueous phase as raw materials specifically includes: mixing the oily compound, the initiator, and the emulsifier to obtain an oil phase, and then adding the aqueous phase to the oil phase over 0.1 to 2 hours, homogenizing to emulsify, and obtaining a high internal phase emulsion.

[0047] By slowly adding the aqueous phase to the oil phase over 0.1 to 2 hours, the aqueous phase is ensured to be fully dispersed. More preferably, the aqueous phase is added in the following manner: the preset time for adding the aqueous phase is divided into two equal parts, with 2 / 3 of the volume of aqueous phase added in the first part and 1 / 3 of the volume of aqueous phase added in the second part.

[0048] In some preferred embodiments, homogenization is performed to emulsify the material for 0.1 to 1 hour.

[0049] By homogenizing and emulsifying the emulsion for 0.1 to 1 h after adding the aqueous phase, the resulting high internal phase emulsion can be made uniform and stable.

[0050] In some embodiments, the strong emission modification of the porous foam includes introducing strong emission groups or strong emission substances; the method of introducing strong emission groups includes introducing strong emission groups through substitution reactions, esterification reactions, or ester substitution reactions, and the introduction of strong emission substances includes introducing strong emission substances through spraying, sputtering, or impregnation. In some preferred embodiments, the strong emission modification of the porous foam is the introduction of strong emission substances, and the method of introducing strong emission substances is impregnation.

[0051] Introducing strong emissive substances into porous foams through impregnation can effectively achieve strong emission modification of porous foams while avoiding damage to the porous structure.

[0052] In some specific embodiments, the introduction of a strong emissive substance into the porous foam via impregnation includes: immersing the porous foam in a chlorosulfonic acid solution; the immersion includes complete immersion or partial immersion, and the partial immersion includes immersing the portion not filled with phase change material into the chlorosulfonic acid solution. In some specific embodiments, the chlorosulfonic acid solution is a dichloroethane solution of chlorosulfonic acid, and the mass percentage concentration of the dichloroethane solution of chlorosulfonic acid is 5% to 10%.

[0053] During their research, the inventors discovered that introducing strong emissive substances into porous foams through impregnation, particularly by immersing the porous foam in a solution to adsorb chlorosulfonic acid, allows for more controllable introduction of chlorosulfonic acid compared to chemical methods such as substitution or esterification to introduce strong emissive substituents. This minimizes damage to the porous material's structure. Complete immersion refers to completely submerging the porous foam in a chlorosulfonic acid solution to achieve overall strong emissivity modification. Partial immersion can also be used, immersing the portion not filled with phase change material (PCM) in the chlorosulfonic acid solution, or immersing both the portion not filled with PCM and the portion partially filled with PCM. During subsequent PCM filling, it is ensured that the unfilled portion undergoes strong emissivity modification. The composite material exhibits optimal overall performance when the mass percentage concentration of the chlorosulfonic acid solution in dichloroethane is between 5% and 10%. Conversely, when the mass percentage concentration of the chlorosulfonic acid solution in dichloroethane is ≥15%, the reflectivity of the composite material decreases.

[0054] In some embodiments, the phase change material is an organic solid-liquid phase change material with a phase change temperature of -30 to 150 °C and an enthalpy of 10 to 300 J / g; more preferably, the phase change temperature of the phase change material is -5 to 100 °C. In some specific embodiments, the phase change material includes one or more of fatty acids, aliphatic hydrocarbons, fatty alcohols, and polyethylene glycol; in some preferred embodiments, the phase change material is docosane or tetradecanoic acid, and more preferably, the phase change material is docosane.

[0055] In some embodiments, the phase change material adsorption is performed at atmospheric pressure or in a solution-assisted manner. In some preferred embodiments, the phase change material adsorption is performed at atmospheric pressure.

[0056] By placing a porous foam modified with strong emission into a molten phase change material, the molten phase change material is partially adsorbed into the pores and / or surface of the porous foam modified with strong emission. This invention fully utilizes the similarity in properties between the phase change material and the porous foam to achieve controllable adsorption of the molten phase change material by the porous foam skeleton. This effectively avoids the influence of the phase change layer on the radiative cooling layer, resulting in a composite material with high latent heat of phase change and radiative cooling characteristics. During the research process, the inventors found that when the adsorbed phase change material is docosane or tetradecanoic acid, the resulting composite material has significantly improved thermal management performance. In particular, when the phase change material is docosane, the resulting composite material has the highest latent heat of phase change, emissivity, and reflectivity.

[0057] On the other hand, an application of the above-mentioned radiation-phase-change coupled thermal management composite material in the field of thermal management is provided.

[0058] Prior to the application for this invention, a series of experiments were conducted. Some of the experimental results are listed below to provide a more detailed description of the invention. The following is a detailed description in conjunction with the embodiments.

[0059] Example 1

[0060] This embodiment provides a method for preparing a radiation- and phase-change coupled thermal management composite material, including:

[0061] (1) 7.5 g of oily compound DVB, 0.1 g of tert-butyl hydroperoxide and iron-based initiator, forming a redox initiation system, and 1.5 g of emulsifier Span 80 were poured into a 100 mL centrifuge tube and mixed evenly on a homogenizer at 500 rpm to obtain a mixture; in this embodiment, the mixing time on the homogenizer was 5 min; the iron-based initiator was ferrous sulfate, and the mass ratio of tert-butyl hydroperoxide to ferrous sulfate was 1:1;

[0062] (2) Add 35 g of water evenly to the above mixture over 10 min, then add 17.5 g of water evenly over 10 min, and emulsify on a homogenizer at 800 rpm for 1 h to obtain a high internal phase emulsion;

[0063] (3) Pour the above emulsion into In the mold, the emulsion temperature is controlled at 80℃, and it is allowed to stand for 12 h to complete the polymerization. The aqueous phase is removed by natural evaporation. The product is then cut into pieces with a height of 1 cm to obtain porous foam.

[0064] (4) Immerse the porous foam in a 5% (w / w) solution of chlorosulfonic acid in dichloroethane, remove it, let it stand for 10 min to allow for full reaction, remove the dichloroethane, and obtain the porous material modified by strong emission.

[0065] (5) Immerse one surface of the porous material modified by strong emission into molten docosane to a height of 1 mm. Under capillary adsorption, the molten docosane spontaneously diffuses into the interior and upwards of the porous material. When the adsorption height reaches 7 mm, the adsorption stops, and a thermal management composite material coupled with radiation and phase change is obtained.

[0066] Example 2

[0067] This embodiment is the same as that in embodiment 1, except that step (2) is to add 5 g of water evenly to the above mixture in 5 min, and then add 2.5 g of water evenly in 5 min, and place it on a homogenizer at 800 rpm for 1 h to emulsify and obtain an emulsion.

[0068] Example 3

[0069] This embodiment is the same as Embodiment 1, except that in step (2), 75 g of water is uniformly added to the above mixture over 30 min, followed by the uniform addition of 37.5 g of water over another 30 min. The mixture is then emulsified on a homogenizer at 800 rpm for 1 h to obtain an emulsion. In step (3), the mold volume is... .

[0070] Example 4

[0071] This embodiment is the same as Embodiment 1, except that in step (1), tert-butyl hydroperoxide and Fe are replaced with an equal amount of AIBN. 2+ The redox initiation system is composed of a redox initiation system; in step (3), the polymerization temperature is 70 °C.

[0072] Example 5

[0073] This embodiment is the same as that in embodiment 1, except that in step (1), the oily compound is 5 g of styrene and 2.5 g of DVB.

[0074] Example 6

[0075] This embodiment is the same as Embodiment 1, except that,

[0076] Step (4) involves spraying the upper surface of the porous foam with a 2% concentration of hydrophobic silicon-based modified spray, so that the spray penetrates to a depth of 1 mm, thereby obtaining the modified porous material; the hydrophobic silicon-based modified spray was purchased from Shanghai Silicon Industry Co., Ltd., model CH228.

[0077] Step (5) involves immersing the lower surface of the modified porous material into molten docosane to a height of 1 mm. Under capillary adsorption, the molten docosane spontaneously diffuses into the interior of the porous material and upwards. When the adsorption height reaches 7 mm, the adsorption is stopped, and a thermal management composite material coupled with radiation and phase change is obtained.

[0078] Example 7

[0079] This embodiment is the same as embodiment 1, except that step (5) is to stop adsorption when the adsorption height reaches 3 mm, and obtain the thermal management composite material coupled with radiation and phase change.

[0080] Example 8

[0081] This embodiment is the same as that in embodiment 1, except that in step (5), molten tetradecanoic acid is used instead of molten docosane.

[0082] Comparative Example 1

[0083] This comparative study examines the effect of emulsifier dosage on the properties of composite materials. The preparation method is the same as in Example 1, except that in step (1), the mass of emulsifier Span 80 is 0.5 g.

[0084] In this comparative example, a highly internal emulsion was not formed. The possible reason is that the amount of emulsifier used was too small, making it difficult to stabilize the oil phase and ultimately preventing the formation of a highly internal emulsion.

[0085] Comparative Example 2

[0086] This comparative example examines the effect of the type of oily compound on the performance of the composite material. The preparation method is the same as that in Example 1, except that in step (1), styrene is used instead of DVB.

[0087] The porous material obtained in this embodiment has an unstable shape, which may be because styrene is a linear monomer and cannot form a cross-linked network, resulting in an unstable shape after polymerization.

[0088] Comparative Example 3

[0089] This comparative example examines the effect of the volume of adsorbed phase change material on the performance of composite materials. It is the same as Example 1, except that in step (5), adsorption is stopped when the adsorption is complete.

[0090] Comparative Example 4

[0091] This comparative example examines the effect of adsorbed strong emissive substances on the performance of composite materials. It is the same as Example 1, except that in step (4), the mass percentage concentration of the dichloroethane solution of chlorosulfonic acid is 15%.

[0092] Example 9

[0093] This embodiment is the same as that of embodiment 1, except that in step (1), 5 g of butyl acrylate and 2.5 g of DVB are used instead of 7.5 g of DVB; step (4) is not included; step (5) is to immerse one surface of the porous foam in molten docosane to a height of 1 mm. Under capillary adsorption, the molten docosane spontaneously diffuses into the interior of the porous material and upwards. When the adsorption height reaches 7 mm, the adsorption stops, and the composite material is obtained.

[0094] Example 10

[0095] This embodiment is the same as that in embodiment 1, except that in step (1), 7.5 g of DVB is replaced with 2.5 g of butyl acrylate, 2.5 g of styrene and 2.5 g of DVB.

[0096] Performance Evaluation

[0097] The encapsulation efficiency, latent heat of phase transition, phase transition temperature, reflectance, and emissivity of the composite materials in each embodiment and comparative example are shown in Table 1. The phase transition temperature and latent heat of phase transition were measured using a DSC-60 differential scanning calorimeter from TA Instruments (USA). The testing method included: placing 10 mg of sample into a crucible, then placing the crucible and reference sample into the sample chamber of the DSC, holding at 100°C for three minutes, cooling to 0°C at a rate of 5°C / min, holding at 0°C for 3 minutes, and then heating back to 100°C at a rate of 5°C / min. The reflectance was measured using a Shimadzu UV-3600 UV-Vis-NIR spectrophotometer from Shimadzu Corporation (Japan). The testing method included: using an integrating sphere attachment and a PTFE backplate to test the baseline, then fixing the test sample on the instrument, with a test wavelength of 200-2500 nm and a test speed of 1 nm / s. The emissivity was measured using a Thermo Fisher Scientific Nicolet spectrophotometer. The results were obtained using an IS50R Fourier transform infrared spectrophotometer. The testing method was based on the mid-infrared integrating sphere testing mode, with a testing speed of 0.05 μm / s and a testing wavelength range of 2.5-14.8 μm. The encapsulation rate was determined by weighing the porous foam (V0), completely immersing the foam in the phase change material, removing the foam and placing filter paper underneath it, allowing it to stand for 8 hours at a temperature 20 °C higher than the phase change temperature of the phase change material, weighing the foam again (V1), and recording the weight. The encapsulation rate was calculated as (V1-V0) / V1. Specific results are shown in Table 1.

[0098] Table 1. Summary of composite material properties in Examples 1-10 and Comparative Examples 1-4

[0099]

[0100] As shown in Table 1, the composite material of Example 1 exhibits high latent heat of phase change, reflectivity, and emissivity, along with high heat storage performance and radiative cooling characteristics. Table 1 also shows that the amount of aqueous phase affects the reflectivity and emissivity of the composite material. When the mass ratio of aqueous phase to oily compound is 1 (Example 2) or 15 (Example 3), the latent heat of phase change and reflectivity of the composite material decrease sharply when the aqueous phase content is low, while the reflectivity of the composite material decreases slightly when the aqueous phase content is too high.

[0101] As can be seen from Examples 1, 5 and Comparative Example 2 in Table 1, the type of oily compound affects the performance of the product composite material. When DVB is used as the oily compound, the product composite material exhibits higher latent heat of phase change, reflectivity and emissivity. When a mixture of styrene and DVB is used as the oily compound, it will affect the latent heat of phase change and reflectivity to a certain extent. Comparative Examples 1 and 2 did not prepare complete porous materials.

[0102] As can be seen from Examples 1 and 6 in Table 1, the emissivity of the composite material corresponding to the hydrophobic silicon-based modification is significantly lower than that of Example 1, indicating that the present invention, which includes impregnation in chlorosulfonic acid solution, can effectively endow the material with high emissivity and improve the emissivity of the composite material.

[0103] As can be seen from Example 1 and Comparative Example 3 in Table 1, when molten docosane is completely adsorbed, the reflectivity and emissivity of the product composite material actually decrease. The possible reason is that the phase change material docosane completely blocks the pores of the radiative cooling material, affecting the high reflectivity of the pores. Combined with the low emissivity of docosane, the emissivity decreases.

[0104] As can be seen from Examples 1 and 8 in Table 1, the latent heat of phase change of the composite material in Example 8 is significantly reduced, indicating that the present invention, using docosane as a phase change material, can effectively improve the latent heat of phase change of the composite material while maintaining high emissivity and emissivity.

[0105] As can be seen from Examples 1, 9 and 10 in Table 1, the composite material obtained by using an oily compound containing butyl acrylate as a monomer has a high reflectivity, while its emissivity is lower than that of Example 1. The possible reason is that, compared with butyl acrylate which has abundant ester groups, strong emission modification is more conducive to improving the emissivity of the composite material.

[0106] Figure 1 Photograph 'a' shows the morphology of the high internal phase emulsion from step (2) of Example 1, which exhibits solid-phase viscoelasticity. Figure 1 b is a photograph of the morphology of the porous foam in step (3) of Example 1, which shows that its texture is uniform.

[0107] Figure 2 The image shown is a scanning electron microscope (SEM) image of the porous foam cross section in step (3) of Example 1. It was obtained by using a Hitachi HHTNT-536-9424 scanning electron microscope. It can be seen that the porous foam cross section has obvious cross-channel structure.

[0108] Figure 3 This is a schematic diagram of the test results of the reflectivity of the thermal management composite material coupled with radiation and phase change in Example 1. It can be seen that the composite material has a high reflectivity in the 250~2500 nm wavelength range, with an average reflectivity of 98.2%.

[0109] Figure 4 The diagram shows the emissivity test results of the composite material prepared in Example 2. It can be seen that the average emissivity is 98.1% in the range of 8~13 μm.

[0110] Figure 5 The image shows the morphology of molten docosane adsorbed in step (5) of Example 1, demonstrating that the method of the present invention can achieve controllable adsorption of phase change materials.

Claims

1. A radiation and phase change coupled thermal management composite material, characterized in that, The radiation cooling material part comprises a porous structure, and a lower half of the pores and / or the surface of the radiation cooling material part are filled with a phase change material.

2. The radiative and phase change coupled thermal management composite of claim 1, wherein, The ratio of the height of the radiation cooling material part filled with the phase change material to the total height of the radiation cooling material part is ≤80%.

3. A method of making the radiative and phase change coupled thermal management composite of claim 1, wherein, It comprises: An oil compound, an initiator, an emulsifier and an aqueous phase are used as raw materials to prepare a high internal phase emulsion; The high internal phase emulsion is polymerized by emulsion polymerization to obtain a porous foam; The porous foam is subjected to strong emission modification; The porous foam after strong emission modification is placed in a molten phase change material, so that the molten phase change material is adsorbed in part of the pores and / or the surface of the porous foam after strong emission modification.

4. The method of claim 3, wherein, The oil compound comprises one or more of styrene, divinylbenzene, methyl methacrylate, butyl acrylate, acrylonitrile, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate and pentaerythritol tetraacrylate; and / or, the initiator comprises one or more of benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobisisoheptyl nitrile, azobis (isopropyl imidazole) hydrochloride, potassium persulfate, ammonium persulfate, alpha-ketoglutaric acid, tert-butyl hydroperoxide and iron-based initiators; and / or, the emulsifier comprises one or more of Span series emulsifiers, polyglycerol fatty acid esters, polyoxyethylene ethers, modified oil ethoxylates, fatty acid salts and diglycerides.

5. The method of claim 4, wherein, The oil compound is divinylbenzene, or a mixture of divinylbenzene and styrene, or a mixture of divinylbenzene and butyl acrylate; and / or, the initiator is azobisisobutyronitrile, or tert-butyl hydroperoxide and iron-based initiators; and / or, the emulsifier is a Span series emulsifier and / or a polyoxyethylene ether.

6. The method of claim 3, wherein, The mass ratio of the oil compound and the emulsifier is 1: (0.1-0.4); and / or, the mass ratio of the oil compound and the initiator is 1: (0.01-0.1); and / or, the mass ratio of the oil compound and the aqueous phase is 1: (1-20).

7. The method of claim 6, wherein, The mass ratio of the oil compound and the emulsifier is 1: (0.2-0.4); and / or, the mass ratio of the oil compound and the initiator is 1: (0.01-0.02); and / or, the mass ratio of the oil compound and the aqueous phase is 1: (5-10).

8. The method of claim 3, wherein, The strong emission modification of the porous foam is achieved by introducing a strong emission substance by impregnation; and / or; the molten phase change material is an organic solid-liquid phase change material, the phase change temperature is -30-150℃, and the enthalpy value is 10-300 J / g.

9. The method of claim 8, wherein, The impregnation solution used for impregnation is a dichloroethane solution of chlorosulfonic acid, and the mass percentage concentration of the dichloroethane solution of chlorosulfonic acid is 5%-10%; and / or, the phase change material is docosane or tetradecanoic acid.

10. The application of the radiation and phase change coupled thermal management composite material according to claim 1 in the field of thermal management.

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