High-latent-heat composite phase change material as well as preparation method and application thereof

Abstract

The invention discloses a high-latent-heat composite phase change material as well as a preparation method and application thereof, and belongs to the field of composite phase change materials. The preparation method of the high-latent-heat composite phase change material comprises the following steps: slowly dropwise adding a water phase into an oil phase on a homogenizing device, and continuously emulsifying after dropwise adding to obtain a highly inward emulsion; the oil phase is a mixture of a polymeric monomer, an emulsifier and a cross-linking agent; the water phase is a mixture of water and functional filler; an initiator is contained in the oil phase or the water phase; the mass ratio of the polymeric monomer to the emulsifier to the cross-linking agent to the initiator to the water to the functional filler is 1: (0.1-0.4): (0-0.5): (0-0.05): (3-20): (0-1); carrying out initiated polymerization on the highly inward emulsion, and drying to obtain a porous framework material; and packaging the solid-liquid phase change material into the porous framework material. The preparation process is simple, the problem that a solid-liquid phase change material is prone to leakage is solved, and the prepared high-latent-heat composite phase change material is high in heat storage density and high in phase change latent heat.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite phase change materials, and particularly relates to a high latent heat composite phase change material and a preparation method and application thereof. BACKGROUND

[0002] Among all phase change materials, solid-liquid phase change materials have become a research hotspot in the field of phase change composite materials due to their high heat storage density, small volume change in the phase change process, non-toxic and corrosion-resistant materials, good chemical and thermal stability and other advantages. However, the defects such as easy leakage and single driving form in the heat storage process are the key to limit its popularization and application. At present, many methods can be used to solve the problem of easy leakage of organic solid-liquid phase change materials, including polymer shaping, microencapsulation, nano-encapsulation and the like. However, although the polymer shaping phase change material is simple and easy to implement, it has a generally low heat storage density, and it is difficult to disperse the composite system uniformly in the functionalization process; although microencapsulation and nano-encapsulation can achieve good encapsulation effect, the preparation process is complex, the technical difficulty is high, and the cost is high. SUMMARY

[0003] In order to solve the problems proposed in the background, the purpose of the present application is to provide a high latent heat composite phase change material and a preparation method and application thereof.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: on the one hand, the present application provides a preparation method of a high latent heat composite phase change material, comprising the following steps:

[0005] (1) slowly adding a water phase to an oil phase on a homogenizing device to obtain a high internal emulsion of water-in-oil after continuing to emulsify on the homogenizing device after the water phase is added; the oil phase is a mixture uniformly mixed by a polymer monomer, an emulsifier and a crosslinking agent; the water phase is a mixture uniformly mixed by water and a functional filler; the oil phase or the water phase contains an initiator (the initiator is selectively dissolved in the oil phase or the water phase according to its solubility); the mass ratio of the polymer monomer, the emulsifier, the crosslinking agent, the initiator, water and the functional filler is 1: (0.1-0.4): (0-0.5): (0-0.05): (3-20): (0-1).

[0006] (2) initiating polymerization of the polymer monomer in the high internal emulsion, and then drying to obtain a porous skeleton material;

[0007] (3) encapsulating a solid-liquid phase change material into the inside of the porous skeleton material to obtain a high latent heat composite phase change material.

[0008] Further, the rotating speed of the homogenizing device in step (1) is 1000-10000 rpm;

[0009] The time for the aqueous phase to be slowly added to the oil phase in step (1) is 10-120 min;

[0010] The emulsification time after the aqueous phase is added in step (1) is 0.1-5 h.

[0011] Further, the polymerizing monomers mentioned in step (1) are selected from at least one of styrene, divinylbenzene (DVB), epoxy resin, and acrylates;

[0012] The emulsifier mentioned in step (1) is selected from at least one of the following: Span series, polyglycerol fatty acid esters, polyoxyethylene ethers, modified oil ethoxylates, fatty acid salts, and diglycerides;

[0013] The crosslinking agent mentioned in step (1) is selected from at least one of divinylbenzene, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

[0014] The initiator mentioned in step (1) is selected from at least one of thermal decomposition initiators, redox initiators, photoinitiators, and radiation initiators;

[0015] The functional filler in step (1) is selected from at least one of photothermal conversion nanofiller, magnetothermal conversion nanofiller, electrothermal conversion nanofiller, thermally conductive enhanced nanofiller, mechanically enhanced nanofiller, and electromagnetic shielding nanofiller.

[0016] Furthermore, the acrylates include at least one of methyl acrylate, butyl acrylate, and butyl methacrylate.

[0017] Furthermore, the Siban series includes at least one of Siban 60, Siban 65, Siban 80, and Siban 85.

[0018] Furthermore, the thermally decomposable initiator includes at least one of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile, potassium persulfate, and ammonium persulfate;

[0019] The redox initiator includes at least one of benzoyl peroxide, lauroyl peroxide, and di(2-ethylhexyl) percarbonate.

[0020] The photoinitiator includes at least one of α-hydroxyalkyl phenyl ketone, acylphosphine oxide, benzophenone, and α-ketoglutaric acid;

[0021] The radiation initiator includes at least one of α-ketoglutaric acid, photoinitiator 1173, initiator 907, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and benzophenone.

[0022] Further, when the initiator is a thermal decomposition type initiator, the temperature of the polymerization in step (2) is 10-90℃, and the time of the polymerization is 0.1-24 h;

[0023] When the initiator is a redox initiator, the temperature of the polymerization in step (2) is 10-90℃, and the time of the polymerization is 0.1-24 h;

[0024] When the initiator is a photoinitiator, the wavelength of the light source of the polymerization in step (2) is 300-420 nm, and the time of the polymerization is 1-60 min;

[0025] When the initiator is a radiation initiator or does not contain an initiator, the condition of the polymerization in step (2) is to apply a radiation source, the radiation source is a Co radiation source, an X-ray machine or an electron accelerator, and the time of the polymerization is 0.01-10 h.

[0026] Further, the photo-thermal conversion nano filler includes at least one of MXene, graphene, polydopamine, melanin;

[0027] The magnetic-thermal conversion nano filler includes at least one of magnetite, doped ferrite, iron nanoparticles, cobalt nanoparticles;

[0028] The electro-thermal conversion nano filler includes at least one of graphene, carbon nanotubes, expanded graphite, silver nanowires;

[0029] The thermal-conductivity-enhancing nano filler includes at least one of boron nitride, silicon carbide, graphene;

[0030] The mechanical-reinforcing nano filler includes at least one of carbon fiber, cellulose, chitosan;

[0031] The electromagnetic shielding nano filler includes at least one of dodecanol, tetradecanol, erythritol.

[0032] Further, the temperature of the drying in step (2) is less than 100℃, and the moisture is completely removed, and the time is not limited.

[0033] Further, the solid-liquid phase change material in step (3) is at least one of saturated alkanes, fatty alcohols, fatty acids, polyethylene glycol, hydrated salts, low-temperature phase change metals.

[0034] Further, the saturated alkanes include at least one of C10-C40 alkanes, paraffin;

[0035] The fatty alcohols include at least one of dodecanol, tetradecanol, erythritol, sorboglycol;

[0036] The fatty acid comprises at least one of palmitic acid, lauric acid, stearic acid;

[0037] The hydrated salt comprises at least one of sodium sulfate decahydrate, calcium chloride hexahydrate, sodium carbonate decahydrate, sodium acetate trihydrate;

[0038] The low-temperature phase change metal comprises at least one of pure gallium, gallium-indium-tin alloy, indium-bismuth-tin alloy.

[0039] Further, the encapsulation method in step (3) is vacuum impregnation, melt impregnation or solution assisted impregnation.

[0040] In another aspect, the application provides a high latent heat composite phase change material prepared by the preparation method described above.

[0041] In another aspect, the application provides the application of the high latent heat composite phase change material described above in thermal energy storage, solar energy utilization, thermal management, waste heat recovery.

[0042] Compared with the prior art, the application has the following beneficial effects:

[0043] 1) The porous framework material prepared by the application is an open-cell material with high porosity and high interconnection, and the porosity is more than 81%, which can encapsulate a large amount of phase change material, and the encapsulation rate is more than 80%, and the highest can reach 95.4%, and the porous framework material can also maintain relatively good mechanical properties and maintain the stability of its own shape, and the high latent heat composite phase change material prepared has high heat storage density and high phase change latent heat, and solves the problem of easy leakage of solid-liquid phase change materials.

[0044] 2) The pore structure of the porous framework material prepared by the application is adjustable, and with the adjustment of the process, the three-dimensional functional framework constructed also has certain controllability, and the performance of the material can be easily controlled.

[0045] 3) The application can introduce functional fillers in an aqueous phase, and through a special dispersion system of the emulsion, the functional fillers are effectively dispersed, and a three-dimensional network is formed, and the porous framework material is given multifunctionality. The introduction of the functional fillers can give the phase change material different thermal energy storage driving modes.

[0046] 4) The preparation process of the high latent heat composite phase change material of the application is simple, and does not need complex equipment or complex conditions, and has great industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 The scanning electron microscope image of the PDVB porous framework material prepared for the embodiment 1 of the application;

[0048] Figure 2A scanning electron microscope image of the high latent heat composite phase change material prepared in Example 1 of the present application;

[0049] Figure 3 A diagram showing the anti-leakage ability of the high latent heat composite phase change material prepared in Example 5 of the present application. DETAILED DESCRIPTION

[0050] In order to better understand the content of the present application, the content of the present application is further described below in combination with specific implementation methods, but the protection content of the present application is not limited to the following examples.

[0051] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values should be understood to be approximate. The exact numerical values of the endpoints of the ranges and separate points are not to be understood as being strictly limited to the exact values recited. At the very least, each minimum numerical limitation should at least be construed in the context as permitting some slack between the minimum and maximum values to allow for experimentation and / or variation.

[0052] The first aspect of the present application provides a preparation method of a high latent heat composite phase change material, comprising the following steps:

[0053] (1) Slowly adding a water phase to an oil phase on a homogenizer, and continuing to emulsify on the homogenizer after the water phase is added to obtain a high internal water-in-oil emulsion; the oil phase is a mixture of polymerized monomers, emulsifiers and cross-linking agents uniformly mixed; the water phase is a mixture of water and functional fillers uniformly mixed; the oil phase or the water phase contains an initiator (the initiator is selectively dissolved in the oil phase or the water phase according to its hydrophilicity);

[0054] (2) Initiating polymerization of the polymerized monomers in the high internal emulsion, and then drying to obtain a porous skeleton material;

[0055] (3) Encapsulating a solid-liquid phase change material into the interior of the porous skeleton material to obtain a high latent heat composite phase change material.

[0056] In the present application, a small amount of initiator can initiate the polymerization of the polymerizable monomer. The mass ratio of the polymerizable monomer to the initiator is 1: (0-0.05), which can be 1:0, 1:0.01, 1:0.02, 1:0.03, 1:0.04, 1:0.05 or a range formed by the two values and values within the range. In order to make the polymerizable monomer polymerize to form a cross-linked skeleton, a cross-linking agent needs to be added to the system to increase the strength of the porous material. The mass ratio of the polymerizable monomer to the cross-linking agent is 1: (0-0.5), which can be 1:0.01, 1:0.02, 1:0.04, 1:0.06, 1:0.08, 1:0.1, 1:0.3, 1:0.5 or a range formed by the two values and values within the range. In order to ensure that the oil phase and the water phase form a stable emulsion, a certain amount of emulsifier needs to be added. The mass ratio of the polymerizable monomer to the emulsifier can be 1: (0.1-0.4), which can be 1:0.1, 1:0.12, 1:0.14, 1:0.16, 1:0.18, 1:0.2, 1:0.3, 1:0.4 or a range formed by the two values and values within the range. In the high-internal emulsion, the water serving as the dispersed phase is removed, leaving a continuous porous structure. When the proportion of water is too low, the porosity of the obtained porous material is low, and even a closed pore structure is generated, resulting in a decrease in the encapsulation rate of the phase change material. When the proportion of water is too high, the pore wall formed after the polymerization of the polymerizable monomer is too thin, and even defects are generated, greatly affecting the mechanical stability of the porous material. Therefore, the mass ratio of the polymerizable monomer to water is 1: (3-20), which can be 1:3, 1:4, 1:5, 1:7, 1:9, 1:11, 1:13, 1:15, 1:17, 1:20 or a range formed by the two values and values within the range. The introduction of functional fillers can endow the phase change material with different thermal energy storage driving modes. Too much functional filler will increase the difficulty of emulsion formation, and the mechanical properties of the porous material after polymerization will be damaged. Therefore, the mass ratio of the polymerizable monomer to the functional filler is 1: (0-1), and the further preferred ratio is 1: (0-0.5), which can be 1:0, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5 or a range formed by the two values and values within the range.

[0057] In the present application, to ensure the formation of the polymer porous framework, the oil phase needs to form the continuous phase in the emulsion, and the water phase needs to form the dispersed phase in the emulsion. Therefore, to ensure that the oil phase always forms a continuous structure during the emulsification process, the water phase needs to be added slowly and uniformly. The ratio of the oil phase to the water phase is different, and the water phase is added for 10-120 min, which can be 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 25 min, 30 min, 35 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min or a range formed by two of the above values and values within the range. After the water phase is added, to ensure that the oil phase and the water phase form a uniform emulsion and the emulsion is stable, continuous emulsification is required for 0.1-5 h, which can be 0.1 h, 0.25 h, 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h or a range formed by two of the above values and values within the range.

[0058] In the present application, to ensure the formation of the homogeneous small-diameter emulsion, the shear force of the homogenizer needs to be large enough, so the rotation speed of the homogenizer is 1000-10000 rpm, which can be 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm, 2000 rpm, 4000 rpm, 6000 rpm, 8000 rpm, 10000 rpm or a range formed by two of the above values and values within the range.

[0059] In the present application, the polymerization monomer is a monomer commonly used in the art and can form a stable water-in-oil high-internal phase emulsion. Preferably, it is at least one of styrene, divinylbenzene, epoxy resin, and acrylate.

[0060] In the present application, to initiate the polymerization of the polymerization monomer, a certain amount of initiator needs to be added. Preferably, it is at least one of thermal decomposition type initiator, redox initiator, photoinitiator, and radiation initiator. In addition, according to the solubility of the initiation system, the initiation system can be selectively dissolved in the oil phase or the water phase.

[0061] In the present application, to ensure the polymerization of the polymerization monomer to form a cross-linked framework and increase the strength of the porous material, a certain amount of cross-linking agent needs to be added. Preferably, it is at least one of divinylbenzene, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, etc.

[0062] In the present application, in order to ensure the formation of the emulsion, a certain amount of emulsifier needs to be added. Preferably, at least one of Span series, polyglycerol fatty acid ester, polyoxyethylene ether, modified oil ethoxylate, fatty acid salt, and diglyceride is used.

[0063] In the present application, the porous material also needs to be endowed with certain functionality, and functional fillers need to be introduced into the high-internal emulsion. Preferably, at least one of the following is used: light-heat conversion nano-filler, magnetic-heat conversion nano-filler, electric-heat conversion nano-filler, heat-conducting enhancement nano-filler, mechanical enhancement nano-filler, and electromagnetic shielding nano-filler.

[0064] In the present application, the polymerization conditions are different according to the selection of the initiator. When the initiator is a thermal decomposition initiator or a redox initiator, the temperature of the polymerization reaction is 10-90℃, and in the preferred case, in order to ensure the stability of the emulsion during polymerization, the polymerization reaction temperature is 10-70℃, which can be 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃ or a range formed by two of the above values and values within the range; in order to ensure the complete completion of the polymerization reaction, the reaction time is 0.1-24 h, which can be 0.1 h, 0.3 h, 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 16 h, 20 h, 24 h or a range formed by two of the above values and values within the range. When the initiator is a photoinitiator, the wavelength of the light source for polymerization is 300-420 nm, which can be 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm or a range formed by two of the above values and values within the range; the polymerization time is 1-60 min, which can be 1 min, 3 min, 5 min, 7 min, 9 min, 10 min, 15 min, 20 min, 30 min, 40 min, 50 min, 60 min or a range formed by two of the above values and values within the range. When the initiator is a radiation initiator or does not contain an initiator, the polymerization condition is to apply a radiation source, and the radiation source is a Co radiation source, an X-ray machine or an electron accelerator; the polymerization time is 0.01-10 h, which can be 0.01 h, 0.05 h, 0.1 h, 0.5 h, 1 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or a range formed by two of the above values and values within the range.

[0065] In the present application, the solid-liquid phase change material is a common solid-liquid phase change material in the art, and preferably at least one of saturated aliphatic hydrocarbon, fatty alcohol, fatty acid, polyethylene glycol, hydrated salt and low-temperature phase change metal is used.

[0066] In the present application, the phase change temperature of the solid-liquid phase change material is 0-150℃, which can be 0℃, 10℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 110℃, 130℃, 150℃ or any range formed by any two of the above values and the values within the range. The latent heat of phase change is 10-300 J / g, which can be 10 J / g, 30 J / g, 50 J / g, 70 J / g, 90 J / g, 110 J / g, 130 J / g, 150 J / g, 170 J / g, 190 J / g, 220 J / g, 240 J / g, 260 J / g, 280 J / g, 300 J / g or any range formed by any two of the above values and the values within the range.

[0067] In the present application, the affinity of the porous framework material and the solid-liquid phase change material obtained by polymerization is different, and the encapsulation method is different. Preferably, the porous framework material and the solid-liquid phase change material with similar properties can adopt the methods of melt impregnation or solution assisted impregnation, and the porous framework material and the solid-liquid phase change material with different properties adopt the method of vacuum impregnation.

[0068] The second aspect of the present application provides a high latent heat composite phase change material prepared by the above method.

[0069] The third aspect of the present application provides the application of the above high latent heat composite phase change material in thermal energy storage, solar energy utilization, thermal management, waste heat recovery and the like.

[0070] In the present application, if not otherwise specified, the required raw materials are all commercially available goods well known to those skilled in the art.

[0071] MXene source: self-made (using HF to etch the aluminum layer in MAX powder, and after purification, dispersed in water to prepare MXene)

[0072] Example 1

[0073] (1) First, di-vinyl benzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) were mixed uniformly to form an oil phase. Then, 9 g of water was slowly added dropwise to the oil phase on a homogenizer (rotating speed 2000 rpm) to form a homogeneous emulsion, and after the water was added, the emulsion was continuously emulsified on the homogenizer for 15 min to obtain a high internal emulsion of water in oil.

[0074] (2) The high internal emulsion was irradiated under a Co radiation source for 10 min to crosslink the DVB in the high internal emulsion to form PDVB. Finally, after drying at 70℃, the PDVB porous framework material was obtained.

[0075] (3) The PDVB porous framework material is gently placed on the surface of the molten docosane, and bubbles will emerge after the PDVB porous framework material adsorbs the docosane and slowly sinks to the bottom of the molten docosane to obtain the high latent heat composite phase change material.

[0076] The PDVB porous framework material is subjected to electron microscope scanning, and the results are shown in FIG. 3. Figure 1 As can be seen from FIG. 3, the PDVB porous framework material exhibits a rich hierarchical pore structure. The pore size of these pores is less than 10 μm, which can effectively limit the phase change material and prevent the phase change material from leaking. Figure 1 The high latent heat composite phase change material is subjected to electron microscope scanning, and the results are shown in FIG. 4. Figure 2 As can be seen from FIG. 4, the pores of the PDVB porous framework material are all occupied by docosane. Moreover, no bubbles and the interface between PDVB and docosane are observed in the cross section of the high latent heat composite phase change material, proving that the adsorption is full and that PDVB and docosane have excellent compatibility. Figure 2

[0077] Example 2

[0078] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g), and α-ketoglutaric acid (0.01 g) are mixed uniformly to form an oil phase. Then, 15 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and the water is added dropwise for 15 min on the homogenizer to obtain a high internal emulsion of water in oil.

[0079] (2) The high internal emulsion is irradiated under a Co radiation source for 10 min to crosslink the DVB in the high internal emulsion to form PDVB. Finally, PDVB porous framework material is obtained after drying at 70°C.

[0080] (3) The PDVB porous framework material is gently placed on the surface of the molten docosane, and bubbles will emerge after the PDVB porous framework material adsorbs the docosane and slowly sinks to the bottom of the molten docosane to obtain the high latent heat composite phase change material.

[0081] Example 3

[0082] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g), and α-ketoglutaric acid (0.01 g) are mixed uniformly to form an oil phase. Then, 4 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and the water is added dropwise for 15 min on the homogenizer to obtain a high internal emulsion of water in oil.

[0083] ​(2) The high internal emulsion is radiated under a Co radioactive source for 10 min to make the DVB in the high internal emulsion crosslink to form PDVB. Finally, the PDVB porous skeleton material is obtained after drying at 70°C.

[0084] (3) The PDVB porous skeleton material is gently placed on the surface of the molten docosane, and after the PDVB porous skeleton material adsorbs the docosane, bubbles will come out and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0085] Example 4

[0086] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) are uniformly mixed to form an oil phase. Then, 20 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and after the water is added dropwise, the emulsion is continuously emulsified on the homogenizer for 15 min to obtain a high internal water-in-oil emulsion.

[0087] (2) The high internal emulsion is radiated under a Co radioactive source for 10 min to make the DVB in the high internal emulsion crosslink to form PDVB. Finally, the PDVB porous skeleton material is obtained after drying at 70°C.

[0088] (3) The PDVB porous skeleton material is gently placed on the surface of the molten docosane, and after the PDVB porous skeleton material adsorbs the docosane, bubbles will come out and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0089] Example 5

[0090] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and azobisisobutyronitrile (AIBN) (0.01 g) are uniformly mixed to form an oil phase. Then, 9 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and after the water is added dropwise, the emulsion is continuously emulsified on the homogenizer for 15 min to obtain a high internal water-in-oil emulsion.

[0091] (2) The high internal emulsion is radiated under a Co radioactive source for 10 min to make the DVB in the high internal emulsion crosslink to form PDVB. Finally, the PDVB porous skeleton material is obtained after drying at 70°C.

[0092] (3) The PDVB porous skeleton material is gently placed on the surface of the molten docosane, and after the PDVB porous skeleton material adsorbs the docosane, bubbles will come out and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0093] The state of docosane and the high latent heat composite phase change material at 25°C and after being placed in an 80°C oven for 1 hour were compared to investigate the leakage resistance of the high latent heat composite phase change material. The results are as follows: Figure 3 As shown. From Figure 3 It can be seen that pure docosane melts into a flowing liquid after being placed in an 80℃ oven for 1 hour, while the high latent heat composite phase change material still maintains its complete structure, exhibiting excellent shape stability and leakage resistance.

[0094] Example 6

[0095] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) were mixed evenly to form an oil phase. Then, 9 g of water was slowly added dropwise to the oil phase in a homogenizer (2000 rpm) to form a homogenized emulsion. After the water was added, the mixture was continuously emulsified in the homogenizer for 15 min to obtain a water-in-oil high inward emulsion.

[0096] (2) The highly inward-oriented emulsion was irradiated with a Co radiation source for 10 min to crosslink the DVB in the highly inward-oriented emulsion to form PDVB. Finally, after drying at 70℃, the PDVB porous framework material was obtained.

[0097] (3) The PDVB porous framework material is pressed into the interior of molten sodium dodecahydrate, and the sodium dodecahydrate is drawn into the interior of the PDVB porous framework material by vacuum impregnation to obtain a high latent heat composite phase change material.

[0098] Example 7

[0099] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) were mixed evenly to form an oil phase. Then, 9 g of 20 mg / mL MXene aqueous solution was slowly added dropwise to the oil phase in a homogenizer (2000 rpm) to form a homogenized emulsion. After the aqueous phase was completely added, the mixture was continuously emulsified in the homogenizer for 15 min to obtain a water-in-oil high inward emulsion.

[0100] (2) The highly inward-oriented emulsion was irradiated with a Co radiation source for 10 min to crosslink the DVB in the highly inward-oriented emulsion to form PDVB. Finally, after drying at 70℃, the PDVB porous framework material was obtained.

[0101] (3) Gently place the PDVB porous framework material on the surface of the molten docosane. After the PDVB porous framework material adsorbs the docosane, bubbles will emerge and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0102] Example 8

[0103] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and a-ketoglutaric acid (0.01 g) were mixed uniformly to form an oil phase. Water (8.82 g) and graphene (0.18 g) were mixed uniformly to form an aqueous phase. Then, the aqueous phase was slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and the emulsion was continuously emulsified on the homogenizer for 15 min after the addition of the aqueous phase was completed to obtain a high-internal emulsion of water-in-oil.

[0104] (2) The high-internal emulsion was irradiated under a Co radioactive source for 10 min to crosslink the DVB in the high-internal emulsion to form PDVB. Finally, a PDVB porous framework material was obtained after drying at 70°C.

[0105] (3) The PDVB porous framework material was gently placed on the surface of molten docosane, and bubbles were generated and slowly sank to the bottom of the molten docosane after the PDVB porous framework material adsorbed the docosane to obtain a high latent heat composite phase change material.

[0106] Example 9

[0107] (1) First, styrene (0.8 g), divinylbenzene (DVB) (0.2 g), Span 80 (0.2 g) and a-ketoglutaric acid (0.01 g) were mixed uniformly to form an oil phase. Then, 9 g of water was slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and the emulsion was continuously emulsified on the homogenizer for 15 min after the addition of the water was completed to obtain a high-internal emulsion of water-in-oil.

[0108] (2) The high-internal emulsion was irradiated under a Co radioactive source for 10 min to crosslink the DVB in the high-internal emulsion to form PDVB. Finally, a PDVB porous framework material was obtained after drying at 70°C.

[0109] (3) The PDVB porous framework material was gently placed on the surface of molten docosane, and bubbles were generated and slowly sank to the bottom of the molten docosane after the PDVB porous framework material adsorbed the docosane to obtain a high latent heat composite phase change material.

[0110] Example 10

[0111] (1) First, butyl acrylate (0.8 g), 1,4-butanediol diacrylate (0.2 g), Span 80 (0.2 g) and a-ketoglutaric acid (0.01 g) were mixed uniformly to form an oil phase. Then, 9 g of water was slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and the emulsion was continuously emulsified on the homogenizer for 15 min after the addition of the water was completed to obtain a high-internal emulsion of water-in-oil.

[0112] (2) The high internal emulsion is radiated under a Co radioactive source for 10 min to cross-link the DVB in the high internal emulsion to form PDVB. Finally, the PDVB porous framework material is obtained after drying at 70°C.

[0113] (3) The PDVB porous framework material is gently placed on the surface of molten docosane, and after the PDVB porous framework material adsorbs the docosane, bubbles will come out and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0114] Comparative Example 1

[0115] First, divinylbenzene (DVB) (1 g), Span 80 (0.05 g), and α-ketoglutaric acid (0.01 g) are mixed uniformly to form an oil phase. Then, 9 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and after the water is added dropwise, the emulsion is continuously emulsified on the homogenizer for 15 min. Finally, the emulsion is difficult to become a high internal emulsion, and the emulsion is not stable.

[0116] Comparative Example 2

[0117] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g), and α-ketoglutaric acid (0.01 g) are mixed uniformly to form an oil phase. Then, 0.5 g of water is slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion, and after the water is added dropwise, the emulsion is continuously emulsified on the homogenizer for 15 min to obtain a uniform emulsion.

[0118] (2) The uniform emulsion is radiated under a Co radioactive source for 10 min to cross-link the DVB in the emulsion to form PDVB. Finally, the PDVB porous framework material is obtained after drying at 70°C.

[0119] (3) The PDVB porous framework material is gently placed on the surface of molten docosane, and after the PDVB porous framework material adsorbs the docosane, bubbles will come out and slowly sink to the bottom of the molten docosane to obtain a high latent heat composite phase change material.

[0120] Comparative Example 3

[0121] First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) were mixed to form an oil phase. 8 g of water and 2 g of graphene were mixed to form an aqueous phase. Then, the aqueous phase was slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion. After the addition of the aqueous phase was completed, the emulsion was continuously emulsified on the homogenizer for 15 min to obtain a uniform emulsion. The uniform emulsion was irradiated under a Co radioactive source for 10 min to crosslink the DVB in the emulsion to form PDVB. It was found that the shape of the obtained PDVB was difficult to stabilize.

[0122] Comparative Example 4

[0123] (1) First, divinylbenzene (DVB) (1 g), Span 80 (0.2 g) and α-ketoglutaric acid (0.01 g) were mixed to form an oil phase. Then, 2 g of water was slowly added dropwise to the oil phase on a homogenizer (at a speed of 2000 rpm) to form a homogeneous emulsion. After the addition of the water was completed, the emulsion was continuously emulsified on the homogenizer for 15 min to obtain a high-internal emulsion of water-in-oil.

[0124] (2) The high-internal emulsion was irradiated under a Co radioactive source for 10 min to crosslink the DVB in the high-internal emulsion to form PDVB. Finally, after drying at 70°C, a PDVB porous framework material was obtained.

[0125] (3) The PDVB porous framework material was gently placed on the surface of molten docosane, and after the PDVB porous framework material adsorbed the docosane, bubbles were generated and slowly sank to the bottom of the molten docosane to obtain a composite phase change material.

[0126] The high latent heat composite phase change materials prepared in Examples 1-10 and the composite phase change materials prepared in Comparative Examples 2 and 4 were subjected to performance determination:

[0127] The porosity of the PDVB porous framework material was tested by a mercury porosimeter. The results are shown in the following table.

[0128] The encapsulation rate of the solid-liquid phase change material was calculated by the formula (V1-V0) / V1, where V0 and V1 are the masses of the PDVB porous framework material before and after adsorbing the solid-liquid phase change material, respectively. The results are shown in the following table.

[0129] The test method for the phase change latent heat was differential scanning calorimetry. 8 mg of the high latent heat composite phase change material was placed in a crucible, and then the crucible and a reference sample were placed in the sample chamber of the DSC. After being kept at 100°C for 3 min, the temperature was decreased to 0°C at a rate of 5°C / min. After being kept at 0°C for 3 min, the temperature was increased to 100°C at a rate of 5°C / min. The results are shown in the following table.

[0130] Test method of phase transition temperature: differential scanning calorimetry. 8 mg of high latent heat composite phase change material is placed in a crucible, and then the crucible and the reference sample are placed in the sample chamber of the DSC. After being kept at 100℃ for 3 min, the temperature is decreased to 0℃ at a rate of 5℃ / min. After being kept at 0℃ for 3 min, the temperature is increased to 100℃ at a rate of 5℃ / min. The results are shown in the following table.

[0131] Light absorption capacity test: the test conditions of the ultraviolet-visible-near infrared spectrophotometer are as follows: substrate: polytetrafluoroethylene diffuse reflection backboard, test mode: reflectance or transmittance, test wavelength: 200-2500 μm, test speed: 1 nm / s. The high latent heat composite phase change material is placed in the test system of the ultraviolet-visible-near infrared spectrophotometer and tested. The absorption rate is calculated by the values of reflectance or transmittance. The results are shown in the following table.

[0132] Mechanical property (compressive strength) test: the PDVB porous framework material is cut into blocks and placed on the compression test mold of the universal testing machine, and the GB / T 1041-2008 standard is used for testing. The results are shown in the following table.

[0133]

[0134] As can be seen from the table, the porous framework material prepared by the application is a high-porosity and highly interconnected open-cell material with a porosity of more than 81%, which can encapsulate a large amount of phase change material, and the encapsulation rate is more than 80%, and the highest can reach 95.4%. At the same time, the porous framework material can also maintain relatively good mechanical properties and maintain the stability of its own shape. The high latent heat composite phase change material prepared has high heat storage density and high phase change latent heat. The light absorption rate of the high latent heat composite phase change material without functional fillers is low, which can be used in the field of radiative cooling. After adding functional fillers, the light absorption rate of the high latent heat composite phase change material is significantly improved, which can effectively absorb sunlight and realize the storage and utilization of solar energy.

[0135] The above is only a specific embodiment of the application, not all embodiments, and any equivalent transformation of the technical solution of the application by a person skilled in the art by reading the specification of the application is covered by the claims of the application.

Claims

1. A method for preparing a high latent heat composite phase change material, characterized in that, Includes the following steps: (1) The aqueous phase is slowly added dropwise to the oil phase on a homogenizing device. After the aqueous phase is added, emulsification is continued on the homogenizing device to obtain a water-in-oil high inward emulsion. The oil phase is a mixture formed by uniformly mixing polymeric monomers, emulsifiers, and crosslinking agents. The aqueous phase is a mixture formed by uniformly mixing water and functional fillers. The oil phase or aqueous phase contains an initiator. The mass ratio of polymeric monomers, emulsifiers, crosslinking agents, initiators, water, and functional fillers is 1:(0.1-0.4):(0-0.5):(0-0.05):(3-20):(0-1). (2) The monomers in the highly inward-oriented emulsion are subjected to initiation polymerization, and then dried to obtain a porous framework material; (3) The solid-liquid phase change material is encapsulated inside the porous framework material to obtain a high latent heat composite phase change material.

2. The preparation method according to claim 1, characterized in that, The rotational speed of the homogenizing device in step (1) is 1000-10000 rpm; The time for the aqueous phase to be slowly added to the oil phase in step (1) is 10-120 min; The emulsification time after the aqueous phase is added in step (1) is 0.1-5 h.

3. The preparation method according to claim 1, characterized in that, The polymer monomers mentioned in step (1) are selected from at least one of styrene, divinylbenzene, epoxy resin, and acrylates; The emulsifier mentioned in step (1) is selected from at least one of the following: Span series, polyglycerol fatty acid esters, polyoxyethylene ethers, modified oil ethoxylates, fatty acid salts, and diglycerides; The crosslinking agent mentioned in step (1) is selected from at least one of divinylbenzene, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate. The initiator mentioned in step (1) is selected from at least one of thermal decomposition initiators, redox initiators, photoinitiators, and radiation initiators; The functional filler in step (1) is selected from at least one of photothermal conversion nanofiller, magnetothermal conversion nanofiller, electrothermal conversion nanofiller, thermally conductive enhanced nanofiller, mechanically enhanced nanofiller, and electromagnetic shielding nanofiller.

4. The preparation method according to claim 3, characterized in that, The thermally decomposable initiator includes at least one of azobisisobutyronitrile, azobisisoheptanenitrile, potassium persulfate, and ammonium persulfate; The redox initiator includes at least one of benzoyl peroxide, lauroyl peroxide, and di(2-ethylhexyl) percarbonate. The photoinitiator includes at least one of α-hydroxyalkyl phenyl ketone, acylphosphine oxide, benzophenone, and α-ketoglutaric acid; The radiation initiator includes at least one of α-ketoglutaric acid, photoinitiator 1173, initiator 907, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and benzophenone.

5. The preparation method according to claim 4, characterized in that, When the initiator is a thermally decomposable initiator, the polymerization temperature in step (2) is 10-90℃ and the polymerization time is 0.1-24 h; When the initiator is a redox initiator, the polymerization temperature in step (2) is 10-90℃ and the polymerization time is 0.1-24 h; When the initiator is a photoinitiator, the wavelength of the light source for polymerization in step (2) is 300-420 nm, and the polymerization time is 1-60 min; When the initiator is a radiation initiator or does not contain an initiator, the polymerization condition in step (2) is to apply a radiation source, which is a Co radiation source, an X-ray machine or an electron accelerator, and the polymerization time is 0.01-10 h.

6. The preparation method according to claim 3, characterized in that, The photothermal conversion nanofiller includes at least one of MXene, graphene, polydopamine, and melanin; The magnetocaloric conversion nanofiller includes at least one of iron oxide, doped ferrite, iron nanoparticles, and cobalt nanoparticles. The electrothermal conversion nanofiller includes at least one of graphene, carbon nanotubes, expanded graphite, and silver nanowires. The thermally conductive enhanced nanofiller includes at least one of boron nitride, silicon carbide, and graphene; The mechanically reinforced nanofiller includes at least one of carbon fiber, cellulose, and chitosan; The electromagnetic shielding nanofiller includes at least one of dodecyl alcohol, tetradecyl alcohol, and erythritol.

7. The preparation method according to claim 1, characterized in that, The solid-liquid phase change material mentioned in step (3) is at least one of saturated aliphatic hydrocarbons, fatty alcohols, fatty acids, polyethylene glycol, hydrated salts, and low-temperature phase change metals.

8. The preparation method according to claim 1, characterized in that, The encapsulation method described in step (3) is vacuum impregnation, melt impregnation, or solution-assisted impregnation.

9. A high latent heat composite phase change material, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8.

10. The application of the high latent heat composite phase change material as described in claim 9 in thermal energy storage, solar energy utilization, thermal management, and waste heat recovery.

Images