Composite aerogel, recyclable heat storage phase change composite material with photo-thermal conversion function, and preparation method and application thereof

Abstract

The present application relates to the field of phase change materials, in particular to a composite aerogel, a recyclable heat storage phase change composite material with light-heat conversion function and a preparation method and application thereof. The composite aerogel contains a polymer and graphene, and the polymer contains a structural unit of a maleic anhydride group and a structural unit of a maleimide group. The composite aerogel can be used as a carrier with a phase change material to obtain a recyclable heat storage phase change composite material with light-heat conversion function, and it can also be recycled in an environmentally friendly way. The recyclable heat storage phase change composite material contains a composite aerogel and a phase change material loaded in the composite aerogel. The recyclable heat storage phase change composite material with light-heat conversion function in the present application not only has light-heat conversion function, but also has low phase change material leakage and can be recycled, truly realizing the use of solar energy in an environmentally friendly way and effective storage, and having high application value in the environmentally friendly use of clean energy.

Description

Technical Field

[0001] This invention relates to the field of phase change materials, specifically to a composite aerogel, a recyclable heat storage phase change composite material with photothermal conversion function, its preparation method, and its application. Background Technology

[0002] With the rapid increase in energy consumption and greenhouse gas emissions, the environmentally friendly utilization of renewable energy sources such as solar energy and waste heat is extremely attractive. However, the mismatch between energy supply and demand due to the temporal and spatial variations in solar energy makes the effective storage of these energy sources a critical issue. Latent heat storage systems based on organic phase change materials (PCMs) possess large storage capacity, near-constant phase change temperatures, and reversible storage and release of heat energy. PCMs can bridge the significant gap between rapidly growing energy demand and limited fossil fuel reserves. Therefore, PCMs are currently widely used in air conditioning systems, building materials, solar energy storage, waste heat recovery, and various electronic products. Organic PCMs, with their advantages of stable performance, low supercooling, and no phase separation, are the most widely studied PCMs, primarily including paraffin wax, fatty acids, fatty alcohols, and other organic compounds. However, the direct use of organic PCMs as energy storage materials presents a risk of leakage, making encapsulation essential to prevent such problems. Furthermore, the reprocessability and recyclability of organic PCMs must be considered to avoid environmental pollution and resource waste.

[0003] Therefore, providing a material with photothermal conversion properties, and combining it with a phase change material to obtain a recyclable cold storage phase change composite material with good photothermal conversion properties, low leakage of the phase change material, and recyclability, would represent a major breakthrough in this field. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the purpose of this invention is to provide a composite aerogel, a recyclable heat storage phase change composite material with photothermal conversion function, its preparation method, and its application. The composite aerogel can be used as a carrier to obtain a recyclable heat storage phase change composite material with photothermal conversion function together with a phase change agent. It can also be recycled in a simple and environmentally friendly way. The recyclable heat storage phase change composite material with photothermal conversion function not only has photothermal conversion function, but also has low leakage of phase change material and can be recycled, truly realizing the environmentally friendly utilization and effective storage of solar energy.

[0005] The inventors of this invention have discovered that maleimide-based copolymers (polymers containing maleic anhydride and maleimide groups) can be prepared using low-cost copolymerization and can be recycled using ammonia. Addressing existing technologies, the applicant has found in their research that mixing such copolymers with graphene oxide and a reducing agent can produce a composite aerogel of maleimide-based copolymers and reduced graphene oxide. Preferably, the aerogel is rapidly and efficiently reduced using microwaves to obtain a water-resistant maleimide-based copolymer-graphene composite aerogel. This composite aerogel can serve as a carrier for phase change materials, preventing leaks in phase change materials, and can be recycled using ammonia to obtain graphene, phase change materials, and polymers. In summary, this invention aims to achieve leak prevention and recycling of phase change materials with photothermal conversion capabilities, providing a composite aerogel suitable for phase change material carriers, as well as a recyclable heat storage phase change composite material with photothermal conversion capabilities, its preparation method, and its applications.

[0006] The first aspect of this invention is to provide a composite aerogel containing a polymer and graphene, wherein the polymer contains structural units with maleic anhydride groups and maleimide groups. This composite aerogel can be used as a carrier to obtain a recyclable heat storage phase change composite material with photothermal conversion function, and can also be recycled in a simple and environmentally friendly manner.

[0007] In a preferred embodiment of the present invention, the Raman spectrum of the composite aerogel surface I D / I G The average value is less than or equal to 1.2, preferably less than or equal to 0.9, and more preferably less than or equal to 0.85.

[0008] According to the present invention, the mass ratio of graphene to polymer can be selected within a wide range. In a preferred embodiment of the present invention, the mass ratio of graphene to polymer is (1:20)-(10:1), preferably (1:10)-(6:1), more preferably (1:5)-(1:1), that is, 1:(1-5). For example, it can be the ratio of 1 to 1, 2, 3, 4, 5, or any two values ​​or any range of any two values.

[0009] According to the present invention, the polymer in the composite aerogel can be dissolved in ammonia water at 0-150°C to form a polymer aqueous solution.

[0010] In a preferred embodiment of the present invention, the graphene in the raw materials for preparing the composite aerogel of the present invention is derived from the reduction of graphene oxide. The graphene oxide needs to be pre-reduced using a reducing agent before microwave reduction. That is, the graphene is obtained by reducing graphene oxide, preferably by pre-reducing the graphene oxide with a reducing agent before microwave reduction.

[0011] According to the present invention, the reducing agent can be selected from a wide range. In a preferred embodiment of the present invention, the reducing agent is selected from at least one of ascorbic acid, gallic acid, sodium borohydride, and amino acids.

[0012] According to the present invention, the maleic anhydride group refers to The maleimide group refers to

[0013] In a preferred embodiment of the present invention, with the total molar amount of structural units containing maleic anhydride groups and structural units containing maleimide groups being 100%, the molar proportion of structural units containing maleimide groups in the polymer is 5%-70%, preferably 10%-60%; more preferably 20%-50%, for example 20%, 25%, 30%, 35%, 40%, 45%, 50%, and any two values ​​or any range of any two values.

[0014] According to the present invention, the polymer can be selected from a wide range. In a preferred embodiment of the present invention, the polymer is derived from a polymer raw material having one or more of the structural units having maleic anhydride, maleimide, maleic acid and ammonium salt, and maleamic acid and ammonium salt groups; that is, the maleic anhydride group and maleimide group in the above-mentioned polymer aerogel are derived from at least one of the maleic anhydride group, maleimide group, maleic acid and ammonium salt group, and maleamic acid and ammonium salt group in the polymer raw material.

[0015] The maleic anhydride group refers to The maleimide group refers to Maleic acid and ammonium salt groups, maleamic acid and ammonium salt groups refer to In the formula, M may be the same or different, and each can be a hydroxyl group, an amino group, or an ammonium group (O-NH4).

[0016] In this invention, the polymer raw material includes, but is not limited to, copolymers of polymeric monomers having one or more of the following groups: maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups, and olefin monomers. For example, this invention can also be achieved when the polymer raw material is a copolymer of styrene, maleic anhydride, vinyl silicone oil, etc. The copolymers of polymeric monomers having one or more of the following groups—maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups, and olefin monomers—have lower raw material costs.

[0017] Preferably, the polymer raw material is a copolymer of a polymeric monomer having one or more of the following groups: maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups, and an olefinic monomer; more preferably, the olefinic monomer is at least one of α-methylstyrene, styrene, and isobutylene.

[0018] More preferably, it comprises an alternating copolymer of a polymeric monomer having one or more of the following groups: maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt, and α-methylstyrene, styrene, and isobutylene.

[0019] As an example, the polymer raw materials described in this invention include, but are not limited to, at least one of styrene-maleic anhydride copolymer and maleic anhydride-isobutylene copolymer.

[0020] In a preferred embodiment of the present invention, the composite aerogel is soluble in ammonia water at 0-150°C to form a polymer aqueous solution. Based on this, the polymer aerogel of the present invention can be easily and environmentally recyclable.

[0021] According to the present invention, the polymer in the composite aerogel has excellent heat resistance and retains excellent heat resistance after recycling, making it very suitable for photothermal conversion heat storage carrier.

[0022] In a preferred embodiment of the present invention, the composite aerogel is prepared by reacting a polymer raw material containing at least one of the structural units of maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups with ammonia water under a closed condition, and then mixing it with graphene oxide and a reducing agent, followed by pre-freezing, freeze-drying, dehydration and deammoniation, and reduction treatment.

[0023] The second aspect of the present invention is to provide a method for preparing the composite aerogel described in the first aspect, comprising reacting a polymer raw material containing at least one of the structural units of maleic anhydride, maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups with ammonia water under a closed condition, then mixing it with graphene oxide and a reducing agent, and then subjecting it to pre-freezing, freeze-drying, dehydration and deammoniation, and reduction treatment to obtain the composite aerogel.

[0024] No crosslinking agent is added in the method for preparing composite aerogel of the present invention.

[0025] In a preferred embodiment of the present invention, the preparation method includes the following steps:

[0026] (1) The polymer raw material is reacted with ammonia water under a closed condition to obtain a polymer aqueous solution;

[0027] (2) The polymer aqueous solution obtained in step (1) is mixed with graphene oxide and a reducing agent to obtain a mixture. The mixture is then pre-frozen and freeze-dried to obtain a composite polymer.

[0028] (3) The composite polymer obtained in step (2) is subjected to heat treatment to dehydrate and deammoniate, and then subjected to microwave irradiation to reduce it, so as to obtain the maleimide copolymer graphene composite aerogel.

[0029] According to the present invention, the amount of polymer raw materials and ammonia water in step (1) can be selected within a wide range. In a preferred embodiment of the present invention, based on the total mass of the reaction system as 100%, the mass fraction of polymer raw materials is 0.1%-30%, preferably 0.5%-10%, more preferably 1%-5%, and based on the mass of ammonia water, the mass fraction of ammonia water in the raw materials is 0.001%-30%, preferably 0.01%-10%, more preferably 0.1%-1%, and the remaining component is water.

[0030] According to the present invention, the reaction conditions in step (1) can be selected within a wide range. In a preferred embodiment of the present invention, the reaction conditions include: a reaction temperature of 0-200°C, preferably 50-150°C, more preferably 80-100°C, and / or a reaction time of 0.01-100 h, preferably 0.5-10 h, more preferably 1-5 h. The reaction pressure is not particularly limited, but is preferably carried out at atmospheric pressure.

[0031] According to the present invention, the conditions in step (2) can be selected within a wide range. In a preferred embodiment of the present invention, in step (2): the graphene oxide is derived from a dispersion containing graphene oxide, and the concentration of graphene oxide in the dispersion (i.e., the mass ratio of graphene oxide to water) is 1-100 mg / mL, preferably 3-30 mg / mL, and more preferably 5-20 mg / mL.

[0032] According to the present invention, the reducing agent can be selected from a wide range. In a preferred embodiment of the present invention, the reducing agent is selected from at least one of ascorbic acid, gallic acid, sodium borohydride, and amino acids.

[0033] According to the present invention, the mass ratio of the reducing agent to graphene oxide can be selected within a wide range. In a preferred embodiment of the present invention, the mass ratio of the reducing agent to graphene oxide is 1:(0.1-20), preferably 1:(1-3), for example, it can be 1 to 1, 1.5, 2, 2.5, 3, or any two values ​​or any range of any two values.

[0034] According to the present invention, the polymer aerogel can be anisotropic or isotropic.

[0035] The difference between anisotropic and isotropic aerogels lies in their pore structure. Anisotropic aerogels exhibit long-range order in their pore structure, primarily due to the directional growth of ice crystals during the pre-freezing stage. During this growth, impurities are expelled, and their aggregation forms the pore walls. Therefore, different unidirectional cold source temperatures during pre-freezing can yield anisotropic aerogels. Various methods can be employed to adjust the unidirectional cold source temperature, including, but not limited to, using liquid nitrogen as the cryogenic source during pre-freezing. A mold containing a mixture of polymer aqueous solution, graphene oxide, and a reducing agent is placed on a copper column immersed in liquid nitrogen, allowing ice crystals to grow upwards from the bottom of the mold.

[0036] Anisotropic aerogels have different pore structures, varying axial and radial thermal conductivity, and different rates of mass and sound transmission. Anisotropic or isotropic aerogels can be selected based on different applications. For example, in the encapsulation of phase change materials in this invention, the inventors discovered that using a preferred anisotropic aerogel significantly reduces leakage, without requiring specific orientation of the anisotropic aerogel.

[0037] According to the present invention, the cold source temperatures of the pre-freezing mixture in all directions may be the same or different. In a preferred embodiment of the present invention, the cold source temperatures of the pre-freezing mixture in all directions are different. Preferably, the unidirectional cold source temperatures of the pre-freezing mixture (i.e., the aqueous solution of the copolymer obtained after the amination reaction, graphene, and reducing agent) are different. In this preferred embodiment, the leakage of the phase change material is lower.

[0038] Anisotropic aerogels can be obtained by using different unidirectional cold source temperatures during pre-freezing. There are various ways to implement the unidirectional cold source temperature, including but not limited to using liquid nitrogen as the low-temperature cold source during pre-freezing, placing the mold on a copper column immersed in liquid nitrogen, and allowing ice crystals to grow upwards from the bottom of the mold.

[0039] Specifically, the pre-freezing conditions can be conventional temperature conditions in the field. The present invention has no particular limitations, as long as the polymer aqueous solution in step (2) is frozen into ice with the mixture of graphene oxide and reducing agent.

[0040] According to the present invention, the conditions for freeze drying can be selected within a wide range. The present invention does not have any particular limitations. In a preferred embodiment of the present invention, the conditions for freeze drying include: a temperature below (-10)°C, for example, below (-20)°C or below (-30)°C, and / or a vacuum degree below 1000 Pa, for example, below 100 Pa or below 10 Pa.

[0041] The freeze-drying process can utilize various existing freeze-drying equipment, such as freeze dryers, freeze spray dryers, and industrial freeze dryers.

[0042] According to the present invention, the conditions in step (3) can be selected within a wide range. In a preferred embodiment of the present invention, the conditions for heat treatment in step (3) include: a temperature of 100-300°C, preferably 120-220°C, more preferably 160-200°C; and a heat treatment time of 0.1-10 hours, preferably 0.5-3 hours, more preferably 1-2 hours.

[0043] According to the present invention, the conditions for microwave irradiation can be selected within a wide range. In a preferred embodiment of the present invention, the microwave irradiation power is 500-2000W; the microwave irradiation time is 1-10s, preferably 2-7s, and more preferably 3-5s.

[0044] According to the present invention, the polymer raw material can be selected from a wide range. In a preferred embodiment of the present invention, the polymer raw material can react with ammonia to obtain a water-soluble polymer.

[0045] In a preferred embodiment of the present invention, the polymer raw material is a polymer having one or more of the structural units selected from maleic anhydride, maleimide, maleic acid and ammonium salt, and maleamic acid and ammonium salt groups; preferably, the polymer raw material is a copolymer comprising a polymeric monomer having one or more of the polymeric monomers selected from maleic anhydride, maleimide, maleic acid and ammonium salt, and maleamic acid and ammonium salt groups and an olefin monomer; more preferably, the olefin monomer comprises at least one of α-methylstyrene, styrene, and isobutylene;

[0046] For example, the polymer raw materials include, but are not limited to, at least one of styrene-maleic anhydride copolymer and maleic anhydride-isobutylene copolymer.

[0047] The polymer raw materials described above are all polymers that have been disclosed in the prior art. They can be obtained from commercially available polymers or prepared according to methods disclosed in the prior art.

[0048] The material of the sealed container is not particularly limited in this invention, and it can be a container made of metal, non-metal, polymer, or other materials.

[0049] The "and / or" in this invention refers to the fact that either one of the two conditions before or after "and / or" can be chosen, or both conditions can coexist.

[0050] A third aspect of the present invention is to provide a recyclable thermal storage phase change composite material comprising a composite aerogel and a phase change material loaded in the composite aerogel; wherein the composite aerogel is the composite aerogel described in the first aspect or the composite aerogel prepared by the preparation method described in the second aspect.

[0051] According to the present invention, the mass ratio of the composite aerogel to the phase change material can be selected within a wide range. In a preferred embodiment of the present invention, the mass ratio of the composite aerogel to the phase change material is 1:(0.05-50). For example, it can be the ratio of 1 to 0.05, 0.1, 0.5, 1, 5, 10, 20, 30, 40, 50, or any two values ​​or any range of any two values.

[0052] According to the present invention, the phase change material can be selected from a wide range, and the phase change material is preferably an organic phase change material, preferably a heat storage phase change material; including but not limited to water-soluble phase change materials and / or non-water-soluble phase change materials, more preferably at least one of polyethylene glycol, lauric acid, octadecyl alcohol, and paraffin.

[0053] In a preferred embodiment of the present invention, under the temperature condition that the phase change material is in a liquid state, the leakage of the phase change material in the recyclable thermal storage phase change composite material is less than 10 wt%, preferably less than 5 wt%, and more preferably less than 2 wt%.

[0054] This invention also provides a method for recycling composite aerogels or recyclable thermal storage phase change composite materials. The recycling method includes mixing and reacting the composite aerogel and / or the recyclable thermal storage phase change composite material with ammonia water under closed conditions until an aqueous solution containing the recycled polymer is obtained. Insoluble substances (graphene, phase change material) are then removed to obtain an aqueous solution of the recycled polymer. This aerogel recycling method does not require the introduction of organic solvents or high-temperature, high-pressure stirring treatment. It only requires a certain concentration of ammonia water, preferably maintained below 100 degrees Celsius, enabling rapid and efficient recycling. This method has low energy consumption, low pollution, and high efficiency. The recovered polymer solution can be reused in the preparation of polymer aerogels.

[0055] According to the present invention, the conditions for the mixing reaction in the recovery method can be selected within a wide range. In a preferred embodiment of the present invention, the temperature of the mixing reaction is 0-200°C, preferably 50-150°C, more preferably 80-100°C, and / or the mixing reaction time is 0.01-100 h, preferably 0.5-10 h, more preferably 1-5 h. The reaction pressure is not particularly limited, but is preferably carried out at atmospheric pressure.

[0056] In a preferred embodiment of the present invention, the recycling method further includes reusing the aqueous solution of the recycled polymer, for example, by continuing step (2) and subsequent steps in the preparation method described in the second aspect of the present invention to re-prepare the composite aerogel.

[0057] A fourth aspect of the present invention is to provide a method for preparing the recyclable thermal storage phase change composite material described in the third aspect, comprising loading the phase change material in the composite aerogel.

[0058] According to the present invention, the method for preparing the recyclable thermal storage phase change composite material includes: obtaining a composite aerogel using the preparation method described in the second aspect; and loading the phase change material into the composite aerogel. The loading method can be any existing loading method in the prior art. Specifically, it can be to adsorb (encapsulate) and / or permeate the phase change material into the composite aerogel after it is in a molten state.

[0059] According to the present invention, the type and ratio of the phase change material can be selected within a wide range, preferably the type and ratio of the phase change material described in the third aspect of the present invention.

[0060] The fifth aspect of the present invention is to provide an application of the recyclable thermal storage phase change composite material described in the fourth aspect in the fields of building energy conservation, air conditioning systems, waste heat utilization, and solar energy storage.

[0061] Through the above technical solution, this invention provides a composite aerogel, a recyclable heat storage phase change composite material with photothermal conversion function, its preparation method, and its application. Compared with the prior art, this invention has the following advantages:

[0062] The composite aerogel in this invention serves as a carrier, and the graphene within it endows the phase change material with photothermal conversion capabilities. The graphene-containing aerogel phase change composite material can heat up to above 70°C within 30 minutes under sunlight irradiation and maintain a temperature above 50°C for an extended period, exhibiting excellent photothermal conversion and heat storage performance. Combined with the heat storage properties of the phase change material, the recyclable heat storage phase change composite material with photothermal conversion capabilities in this invention enables highly efficient utilization of solar energy.

[0063] The composite aerogel and the recyclable heat storage phase change composite material with photothermal conversion function in this invention can be recycled and reused in a green and environmentally friendly manner.

[0064] Both the polymers in the composite aerogel and the recycled polymers have good heat resistance. At the same time, the porous structure of the composite aerogel results in low leakage of the phase change material. All of these provide stability assurance for photothermal conversion and heat storage.

[0065] In summary, the recyclable heat storage phase change composite material with photothermal conversion function in this invention not only has photothermal conversion function, but also has good heat storage performance. Moreover, the leakage of the phase change material is low, and the whole material can be recycled, truly realizing the environmentally friendly use and effective storage of solar energy. It has extremely high application value in the environmentally friendly use of clean energy. Attached Figure Description

[0066] Figure 1 The DSC curves and glass transition temperatures (Tg) of the maleimide-based aerogel in Comparative Example 1 and the recovered polymer aerogel in Example 4 are shown.

[0067] Figure 2 The thermogravimetric curves are those of the maleimide-based aerogel in Comparative Example 1 and the recovered polymer aerogel in Example 4.

[0068] Figure 1 and Figure 2 The test results show that maleimide-based aerogels have good heat resistance, with a glass transition temperature of around 250℃ and a decomposition temperature of around 300℃. The heat resistance of aerogels prepared from recycled polymers is higher than that of unrecycled polymers, proving that the polymers before and after recycling have good heat resistance and that the recycling process is green and environmentally friendly.

[0069] Figure 3 The phase change materials of Examples 2 and 5 are shown in a solar irradiance and removal irradiance temperature curve.

[0070] Figure 3 The test results show that graphene endows phase change materials with photothermal conversion function. The graphene-containing aerogel phase change composite material can be heated to above 70°C within 30 minutes under simulated sunlight irradiation and can maintain the temperature above 50°C for a long time. It has good photothermal conversion performance and heat storage performance, and can realize the efficient utilization of solar energy.

[0071] Figure 4 The maleimide-based copolymer graphene aerogel phase change composite material (a) obtained from Example 2, the recycled graphene phase change composite material (b), and the polymer aerogel (c) are described in Example 4. It is evident that the materials in the recyclable heat storage phase change composite material with photothermal conversion function of this invention can be recycled and reused. Detailed Implementation

[0072] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0073] The present invention will be further described below with reference to the embodiments; however, the present invention is not limited to these embodiments.

[0074] The experimental data in the examples were measured using the following instruments and methods:

[0075] 1. Raman spectrum ID / IG of the aerogel obtained in the example:

[0076] The tests were performed using a HORIBA JOBIN YVON Lab RAM HR800 Raman spectrometer. The curves were processed using the instrument's built-in software, and the ID and IG values ​​were obtained.

[0077] 2. Thermal stability of the aerogel obtained in the examples:

[0078] Thermogravimetric analysis (TGA, Mettler Toledo, Switzerland) was used to determine the thermal stability of the samples, with 5 mg of aerogel used for testing. The tests were conducted under a nitrogen flow, with a heating rate of 20 °C / min, and a temperature range from 50 °C to 550 °C.

[0079] 3. Glass transition temperature of the embodiment:

[0080] The glass transition temperature of the samples was determined using Perkin-Elmer pyris. -1 Differential scanning calorimetry (DSC) was performed, calibrated using indium and zinc standards. 5–6 mg of sample was injected from a syringe and heated from 150 °C to 300 °C under a nitrogen flow, held at 300 °C for 3 minutes. The sample was then cooled to 150 °C for 1 minute and reheated to 300 °C. All heating and cooling cycles were programmed to a rate of 10 °C / min. The glass transition temperature (Tg) was determined based on the relevant peaks in the DSC curve.

[0081] 4. Phase change material simulated temperature change curve under sunlight

[0082] The phase change material was cut into 3cm*3cm*0.3cm sheets as test samples. Sunlight was simulated at 20 degrees Celsius using a Sirius-SS300A-D solar simulator manufactured by Beijing Zhuoli Hanguang Instrument Co., Ltd. The samples were placed in an uncovered polystyrene foam box, and the temperature change of the phase change composite material was monitored throughout the process using thermocouples. Initially, the light intensity was 100mW / cm². 2 After irradiating the simulated light source for approximately 34 minutes under a sunlight intensity of (one level), the simulated light source was then turned off.

[0083] 5. Phase change material leakage test:

[0084] Take 15g of the sample obtained in the example, place the filter paper on a 120°C heating table, place the sample on the filter paper for 10 minutes, remove the sample, weigh the sample to obtain m (g), and the leakage amount is: m / 15*100wt%. If the sample is completely melted and cannot be removed, the leakage amount is 100wt%.

[0085] 6. The test method for phase transition temperature is as follows:

[0086] The thermal properties of aerogels and phase change materials were measured using differential scanning calorimetry (DSC) with a Perkin-Elmer pyris-1 calibrated using indium and zinc standards. For aerogels, samples were heated from 20 to 150 °C under a nitrogen flow, held at 20 °C and 150 °C for 5 min each. For phase change materials, samples were heated from 50 °C to 300 °C under a nitrogen flow, held at 50 °C and 300 °C for 5 min each. The programmed rate for all heating and cooling processes was 20 °C / min. The latent heat of fusion ΔHm and latent heat of solidification ΔHf, as well as the melting temperature Tm and solidification temperature Tf, were determined based on the correlation peaks of the DSC curves.

[0087] Preparation Example 1

[0088] Polymer preparation in this embodiment of the invention: 500 ml of isoamyl acetate was placed in a 1000 ml three-necked flask, and nitrogen gas was purged for 30 min to remove oxygen. 24.5 g of maleic anhydride and 26 g of styrene were added to the flask. After complete dissolution, 0.4 g of azobisisobutyronitrile (AIBN) was added, and the water bath temperature was raised to 70 °C, and the reaction was carried out for 7 h. After the reaction, the mixture was centrifuged at 10000 rpm for 10 min, the supernatant was removed, 500 ml of methanol was added, and the mixture was stirred for 0.5 h. After centrifugation, the supernatant was removed, and the process was repeated twice. Then, the mixture was dried under vacuum at 140 °C for 24 h to obtain the styrene-maleic anhydride copolymer.

[0089] Example 1

[0090] Take 93.2g of water and add it to a glass bottle with a cap. Then add 2.8g of ammonia water with a mass fraction of 25% and 4g of maleic anhydride-styrene copolymer. Tighten the cap of the glass bottle and put it in an oven at 95°C. After 4 hours, take it out to obtain a homogeneous polymer solution with a mass fraction of 4%.

[0091] Add 100g of 20mg / ml graphene oxide aqueous solution to a glass bottle, then add 4g of ascorbic acid. Stir magnetically at 1000r / min for 5min until homogeneous. Quickly pour the mixture into a cylindrical mold with a copper bottom and polytetrafluoroethylene walls, and place it on a copper column in a liquid nitrogen bath. After pre-freezing (i.e., freezing the mixture into ice), place it in a freeze dryer (temperature below -30℃, pressure below 10Pa) and freeze-dry for 72 hours to obtain anisotropic water-soluble GO / SMI composite aerogel.

[0092] The aerogel was then placed in a nitrogen-filled polytetrafluoroethylene liner and heat-treated in a 180°C constant temperature oven for 2 hours. The sample was then removed and placed in a nitrogen-filled sealed quartz jar and microwave-treated (irradiation power of 800W) for 3 seconds to obtain maleimide-styrene copolymer-graphene composite aerogel (i.e., the composite aerogel in this invention).

[0093] Example 2

[0094] Maleimide-graphene composite aerogel was prepared according to the method in Example 1. 0.2g of maleimide-graphene composite aerogel was placed in a polytetrafluoroethylene beaker containing 20g of sliced ​​paraffin. The container was placed in a vacuum oven and kept at 100°C for 2 hours. The molten paraffin penetrated into the maleimide-graphene composite aerogel, thereby obtaining an aerogel phase change composite material. The aerogel phase change composite material was removed from the container, and then the excess phase change material on the surface of the aerogel phase change composite material was wiped dry. After being placed at room temperature for 2 hours, it was weighed to obtain a maleimide-based copolymer graphene aerogel phase change composite material (approximately 10g of adsorbed paraffin).

[0095] Example 3

[0096] The phase change material in Example 2 was replaced with octadecyl alcohol (purchased from Aladdin), and the rest of the experiments were the same as in Example 2.

[0097] The recovery effect of the obtained phase change composite material is similar to that of Example 2.

[0098] Example 4

[0099] The phase change composite material sample obtained in Example 2 was ground into powder. 5g of the powder was placed in a capped glass bottle, and then 0.2g of 25% ammonia and 30ml of water were added. The mixture was heated to 95°C and maintained under magnetic stirring at 1000r / min for 1 hour. Afterward, it was filtered while hot. Figure 4 In step a), the filtrate was concentrated by heating to approximately 5 ml, pre-frozen in a mold freezer, and then freeze-dried in a freeze dryer (temperature below -30°C, pressure below 10 Pa) to obtain the recovered polymer aerogel. Figure 4 c) After the filter cake is naturally dried, it is placed in a small beaker, heated to 100°C to melt, and kept for 1 hour. After cooling, a high-value-added product, graphene phase change composite material, is obtained, which is then cut and shaped as needed. Figure 4 (b) As can be seen, the materials in the recyclable heat storage phase change composite material with photothermal conversion function in this invention can be recycled and reused separately.

[0100] Example 5

[0101] Take 91.5g of water and add it to a glass bottle with a cap. Then add 3.5g of ammonia water with a mass fraction of 25% and 5g of maleic anhydride-styrene copolymer. Tighten the cap of the glass bottle and put it in an oven at 95°C. After 4 hours, take it out to obtain a homogeneous polymer solution with a mass fraction of 5%.

[0102] The polymer solution was poured into 6 molds, 15 ml of solution was poured into each mold, and the molds were frozen at -30°C for 2 hours. The frozen samples were then transferred to a freeze dryer and freeze-dried (below -30°C and below 10 Pa) for 72 hours. The resulting water-soluble polymer aerogel was then removed. The water-soluble polymer aerogel was placed in a constant temperature container and heat-treated at 180°C to dehydrate and deaminate to obtain maleimide-based aerogel.

[0103] 0.5g of maleimide-based polymer aerogel was placed in a 30ml polytetrafluoroethylene beaker containing 20g of sliced ​​paraffin. The container was placed in a vacuum oven at 100℃ for 2 hours to obtain an aerogel phase change composite material. The aerogel phase change composite material was removed from the container, and then the excess phase change material on the surface of the aerogel phase change composite material was wiped dry. After being left at room temperature for 2 hours, the aerogel phase change composite material was weighed to obtain a maleimide-based copolymer aerogel phase change composite material (approximately 7g of adsorbed paraffin).

[0104] Example 6

[0105] The microwave treatment time in Example 1 was changed to 1 second, and the other preparation steps were the same as in Example 1.

[0106] Example 7

[0107] Take 93.2g of water and add it to a glass bottle with a cap. Then add 2.8g of ammonia water with a mass fraction of 25% and 4g of maleic anhydride-styrene copolymer. Tighten the cap of the glass bottle and put it in an oven at 95°C. After four hours, take it out to obtain a homogeneous polymer solution with a mass fraction of 4%.

[0108] Add 100g of 20mg / ml graphene oxide aqueous solution to a glass bottle, then add 4g of ascorbic acid. Stir magnetically at 1000r / min for 5min until homogeneous. Quickly pour the mixture into a cylindrical mold with a copper bottom and polytetrafluoroethylene walls, and place it on a copper column in a liquid nitrogen bath. After pre-freezing, freeze-dry in a freeze dryer (below -30℃, below 10Pa) for 72 hours to obtain anisotropic water-soluble GO / SMI composite aerogel.

[0109] The aerogel was then placed in a nitrogen-filled polytetrafluoroethylene liner and heat-treated in a 180°C constant temperature oven for 2 hours. The sample was then removed and placed in a sealed quartz jar filled with nitrogen, and microwave-treated (irradiation power of 800W) for 5 seconds to obtain maleimide-styrene copolymer-graphene composite aerogel.

[0110] Example 8

[0111] Take 93.2g of water and add it to a glass bottle with a cap. Then add 2.8g of ammonia water with a mass fraction of 25% and 4g of maleic anhydride-styrene copolymer. Tighten the cap of the glass bottle and put it in an oven at 95°C. After four hours, take it out to obtain a homogeneous polymer solution with a mass fraction of 4%.

[0112] Add 100g of 20mg / ml graphene oxide aqueous solution to a glass bottle, then add 4g of ascorbic acid. Stir magnetically at 1000r / min for 5min until homogeneous. Quickly pour the mixture into a cylindrical mold with a copper bottom and polytetrafluoroethylene walls, and place it on a copper column in a liquid nitrogen bath. After pre-freezing, freeze-dry in a freeze dryer (below -30℃, below 10Pa) for 72 hours to obtain anisotropic water-soluble GO / SMI composite aerogel.

[0113] The aerogel was then placed in a nitrogen-filled polytetrafluoroethylene liner and heat-treated in a 180°C constant temperature oven for 2 hours. The sample was then removed and placed in a sealed quartz jar filled with nitrogen, and microwave-treated (irradiation power of 800W) for 7 seconds to obtain maleimide-styrene copolymer-graphene composite aerogel.

[0114] Example 9

[0115] Take a reaction vessel with a polytetrafluoroethylene inner liner, add 20.5g of water, then add 4g of ammonia water with a mass fraction of 25% and 0.5g of maleic anhydride-styrene copolymer. Place the reaction vessel in an oven and keep it at 150℃. After 10 hours, take it out to obtain a homogeneous polymer solution.

[0116] 75g of 40mg / ml graphene oxide aqueous solution and 3g of ascorbic acid were added to a reaction vessel. The mixture was magnetically stirred at 1000r / min for 5min until homogeneous. The mixture was then quickly poured into a cylindrical mold with a copper bottom and polytetrafluoroethylene walls, and placed on a copper column in a liquid nitrogen bath. After pre-freezing, the mold was placed in a freeze dryer (below -30℃ and below 10Pa) and freeze-dried for 72 hours to obtain anisotropic water-soluble GO / SMI composite aerogel.

[0117] The aerogel was then placed in a nitrogen-filled polytetrafluoroethylene liner and heat-treated in a 200°C constant temperature oven for 2 hours. The sample was then removed and placed in a sealed quartz jar filled with nitrogen, and microwave-treated (irradiation power of 500W) for 3 seconds to obtain maleimide-styrene copolymer-graphene composite aerogel.

[0118] 0.2g of maleimide-based polymer aerogel was placed in a 30ml polytetrafluoroethylene beaker containing 20g of sliced ​​paraffin. The container was placed in a vacuum oven at 100℃ for 2 hours to obtain an aerogel phase change composite material. The aerogel phase change composite material was removed from the container, and then the excess phase change material on the surface of the aerogel phase change composite material was wiped dry. After being placed at room temperature for 2 hours, a copolymer graphene aerogel phase change composite material (approximately 4g of adsorbed paraffin) was obtained.

[0119] Example 10

[0120] Add 91.5g of water to a glass bottle with a cap, then add 3.5g of ammonia water with a mass fraction of 25% and 5g of maleic anhydride-styrene copolymer. After tightening the cap, place the bottle in an oven at 95°C. After 4 hours, remove the bottle to obtain a homogeneous polymer solution with a mass fraction of 5%. Dry the solution at room temperature to obtain a polymer containing maleic acid and maleic ammonium groups.

[0121] The obtained polymer was placed in a glass bottle with a cap, 41.5g of water was added, and then 0.04g of ammonia solution with a mass fraction of 25% was added. The glass bottle was then tightened and placed in an oven at 20°C. After 0.5 hours, a homogeneous polymer solution was obtained.

[0122] Add 50g of 6mg / ml graphene oxide aqueous solution and 0.9g of ascorbic acid to a glass bottle. Stir magnetically at 1000r / min for 5min until homogeneous. Then, quickly pour the mixture into a cylindrical mold with a copper bottom and polytetrafluoroethylene walls, and place it on a copper column in a liquid nitrogen bath. After pre-freezing, freeze-dry in a freeze dryer (below -30℃ and below 10Pa) for 72 hours to obtain anisotropic water-soluble GO / SMI composite aerogel.

[0123] The aerogel was then placed in a nitrogen-filled polytetrafluoroethylene liner and heat-treated in a 130°C constant temperature oven for 2 hours. The sample was then removed and placed in a nitrogen-filled sealed quartz jar and microwave-treated (irradiation power of 2000W) for 3 seconds to obtain maleimide-styrene copolymer-graphene composite aerogel.

[0124] 0.2g of maleimide-based polymer aerogel was placed in a 30ml polytetrafluoroethylene beaker containing 20g of sliced ​​paraffin. The container was placed in a vacuum oven at 100℃ for 2 hours to obtain an aerogel phase change composite material. The aerogel phase change composite material was removed from the container, and then the excess phase change material on the surface of the aerogel phase change composite material was wiped dry. After being placed at room temperature for 2 hours, a copolymer graphene aerogel phase change composite material (approximately 6g of adsorbed paraffin) was obtained.

[0125] The phase transition temperature and latent heat of phase transition are similar to those of Example 2.

[0126] Comparative Example 1

[0127] Take 91.5g of water and add it to a glass bottle with a cap. Then add 3.5g of 25% ammonia and 5g of maleic anhydride-styrene copolymer. Tighten the cap of the glass bottle and put it in an oven at 95°C. After four hours, take it out to obtain a homogeneous 5% by mass polymer solution.

[0128] The polymer solution was poured into 6 molds, 15 ml of which was poured into each mold, and then placed in a freezer at -30°C for 2 hours. The frozen samples were then transferred to a freeze dryer (temperature below -30°C, pressure below 10 Pa) and freeze-dried for 72 hours. The resulting water-soluble polymer aerogel was then removed. The water-soluble polymer aerogel was placed in a constant temperature container and heat-treated at 180°C for 2 hours to dehydrate and deaminate, thus obtaining maleimide-based aerogel.

[0129] Comparative Example 2

[0130] Place 20g of sliced ​​paraffin into a 30ml polytetrafluoroethylene beaker, put the container in a vacuum oven at 100℃ for 2 hours, remove it, and let it stand at room temperature for 2 hours to obtain paraffin phase change material (i.e., pure phase change material).

[0131] Test case

[0132] The ID / IG test results of the aerogels prepared in Examples 1 and 6-8 are listed in Table 1; the leakage of the phase change materials prepared in Examples 2, Comparative Examples 2 and 5 are listed in Table 2; the DSC curves and glass transition temperatures (Tg) of Comparative Examples 1 and 4 are shown in Table 2. Figure 1 The thermogravimetric curves of Comparative Example 1 and Example 4 are listed below. Figure 2 The phase change materials of Examples 2 and 5 are listed in a solar radiation intensity and removal light temperature curve. Figure 3 .

[0133] Figure 3 The test results show that graphene endows phase change materials with photothermal conversion capabilities. The graphene-containing aerogel phase change composite material can heat up to above 70°C within 30 minutes and maintain a temperature above 50°C for a long time, exhibiting excellent photothermal conversion performance and enabling efficient utilization of solar energy. The composite phase change material in Example 6 was tested using the same method. Compared to Example 2, the photothermal conversion performance of the composite phase change material in Example 2 is superior to that in Example 6.

[0134] Table 1

[0135] Example 1 0.85 Example 6 1.07 Example 7 0.88 Example 8 0.91

[0136] The test results in Table 1 show that the composite aerogel prepared by this invention has a high reduction efficiency, and can reach a high degree of reduction in 3 seconds, which is beneficial for rapid and large-scale industrial preparation.

[0137] Table 2

[0138] Example 2 1.8wt% Comparative Example 2 100wt% Example 5 3.1wt% Example 3 1.2wt%

[0139] The test results in Table 2 show that aerogel has a good anti-leakage effect on phase change materials and has good application prospects.

[0140] Table 3

[0141]

[0142]

[0143] According to the data in Table 3, porous aerogels cause very little loss of latent heat in phase change materials. High latent heat phase change composites can be prepared using different organic phase change materials. The addition of aerogels will slightly reduce the melting temperature and solidification temperature of phase change materials.

[0144] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0145] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0146] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0147] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0148] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0149] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art believe that the combination is obviously unreasonable.

Claims

1. A composite aerogel comprising a polymer and graphene, wherein the polymer contains structural units with maleic anhydride groups and structural units with maleimide groups; the mass ratio of graphene to polymer is (1:20) to (10:1). The polymer is derived from a structural unit having maleic anhydride, optionally containing one or more of the structural units containing maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups; the polymer raw material is a copolymer of a polymeric monomer having a maleic anhydride group, optionally containing one or more of the polymeric monomers containing maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups and an olefinic monomer.

2. The composite aerogel according to claim 1, characterized in that: Raman spectra of the surface of the composite aerogel I D / I G The average value is less than or equal to 1.2; and / or, The mass ratio of graphene to polymer is (1:10)-(6:1).

3. The composite aerogel according to claim 1, characterized in that: Raman spectra of the composite aerogel surface I D / I G The average value is less than or equal to 0.9; and / or, The mass ratio of graphene to polymer is (1:5) to (1:1).

4. The composite aerogel according to claim 1, characterized in that: Raman spectra of the surface of the composite aerogel I D / I G The average value is less than or equal to 0.

85.

5. The composite aerogel according to claim 1, characterized in that: The polymer in the composite aerogel can dissolve in ammonia water at 0-150℃ to form a polymer aqueous solution.

6. The composite aerogel according to claim 1, characterized in that: The graphene is obtained by reducing graphene oxide.

7. The composite aerogel according to claim 6, characterized in that: The graphene is obtained by first pre-reducing graphene oxide with a reducing agent, and then reducing it with microwaves.

8. The composite aerogel according to claim 7, characterized in that: The reducing agent is selected from at least one of ascorbic acid, gallic acid, sodium borohydride, and amino acids.

9. The composite aerogel according to claim 1, characterized in that: The olefin monomer is at least one of α-methylstyrene, styrene, and isobutylene.

10. The composite aerogel according to any one of claims 1-9, characterized in that: The composite aerogel is prepared by reacting a polymer raw material containing maleic anhydride structural units, optionally containing at least one of maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups, with ammonia water under a closed condition, then mixing it with graphene oxide and a reducing agent, and finally pre-freezing, freeze-drying, dehydrating and deammonising, and reducing the mixture.

11. A method for preparing the composite aerogel according to any one of claims 1-10, comprising reacting a polymer raw material containing a structural unit of maleic anhydride, optionally containing at least one of a structural unit containing maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups, with ammonia water under a closed condition, then mixing with graphene oxide and a reducing agent, and then subjecting it to pre-freezing, freeze-drying, dehydration and deammoniation, and reduction treatment to obtain the composite aerogel; The polymer raw material is a copolymer of a polymeric monomer having a maleic anhydride group and optionally containing one or more of maleimide, maleic acid and ammonium salt, maleamic acid and ammonium salt groups and an olefinic monomer.

12. The preparation method according to claim 11, characterized in that... Includes the following steps: (1) The polymer raw material is reacted with ammonia water under a closed condition to obtain a polymer aqueous solution; (2) The polymer aqueous solution obtained in step (1) is mixed with graphene oxide and a reducing agent to obtain a mixture, which is then pre-frozen and freeze-dried to obtain a composite polymer; (3) The composite polymer obtained in step (2) is subjected to heat treatment and then microwave irradiation to obtain the composite aerogel.

13. The preparation method according to claim 12, characterized in that: In step (1), the mass fraction of polymer raw materials used is 0.1%-30% based on the total mass of the reaction system of 100%, the mass fraction of ammonia used is 0.001%-30% based on the mass of ammonia in ammonia water, and the remaining components are water.

14. The preparation method according to claim 12, characterized in that: In step (1), the mass fraction of polymer raw materials is 0.5%-10% based on the total mass of the reaction system (100%), the mass fraction of ammonia is 0.01%-10% based on the mass of ammonia in ammonia water, and the remaining components are water.

15. The preparation method according to claim 12, characterized in that: In step (1), the total mass of the reaction system is 100%, the mass fraction of the polymer raw material is 1%-5%, the mass fraction of the ammonia in the ammonia water is 0.1%-1%, and the remaining components are water.

16. The preparation method according to claim 12, characterized in that: In step (1), the reaction conditions include: The reaction temperature is 0-200℃, and / or the reaction time is 0.01-100h.

17. The preparation method according to claim 12, characterized in that: In step (1), the reaction conditions include: The reaction temperature is 50-150℃, and / or the reaction time is 0.5-10h.

18. The preparation method according to claim 12, characterized in that: In step (1), the reaction conditions include: The reaction temperature is 80-100℃, and / or the reaction time is 1-5h.

19. The preparation method according to claim 12, characterized in that: In step (2): The graphene oxide is derived from a dispersion containing graphene oxide, wherein the concentration of graphene oxide in the dispersion is 1-100 mg / mL; and / or, The reducing agent is selected from at least one of ascorbic acid, gallic acid, sodium borohydride, and amino acids; and / or, The mass ratio of the reducing agent to graphene oxide is 1:(0.1-20); and / or, During the pre-freezing process, the temperature of the cold source in all directions of the mixture may be the same or different; and / or, Freeze-drying conditions include: a temperature below -10°C; and / or a vacuum degree below 1000 Pa.

20. The preparation method according to claim 12, characterized in that: In step (2): The graphene oxide is derived from a dispersion containing graphene oxide, wherein the concentration of graphene oxide in the dispersion is 3-30 mg / mL; and / or, The mass ratio of the reducing agent to graphene oxide is 1:(1-3); and / or, During the pre-freezing process, the temperature of the cold source in each direction of the mixture is different.

21. The preparation method according to claim 12, characterized in that: In step (2): The graphene oxide is derived from a dispersion containing graphene oxide, wherein the concentration of graphene oxide in the dispersion is 5-20 mg / mL; and / or, The temperature of the unidirectional cold source where the mixture is located during pre-freezing is different.

22. The preparation method according to claim 12, characterized in that: In step (3): The conditions for heat treatment include: a temperature of 100-300℃; a heat treatment time of 0.1-10 hours; and / or, The microwave irradiation power is 500-2000W; the microwave irradiation time is 1-10s.

23. The preparation method according to claim 12, characterized in that: In step (3): The heat treatment conditions include: a temperature of 120-220℃; a heat treatment time of 0.5-3 hours; and / or, The microwave irradiation power is 500-2000W; the microwave irradiation time is 2-7s.

24. The preparation method according to claim 12, characterized in that: In step (3): The heat treatment conditions include: a temperature of 160-200℃; a heat treatment time of 1-2 hours; and / or, The microwave irradiation power is 500-2000W; the microwave irradiation time is 3-5s.

25. The preparation method according to any one of claims 11-24, characterized in that: The polymer raw material can react with ammonia to obtain a water-soluble polymer; and / or, The olefin monomer includes at least one of α-methylstyrene, styrene, and isobutylene.

26. The preparation method according to any one of claims 11-24, characterized in that: The polymer raw material is at least one of styrene-maleic anhydride copolymer and maleic anhydride-isobutylene copolymer.

27. A recyclable thermal storage phase change composite material, comprising a composite aerogel and a phase change material loaded in the composite aerogel; The composite aerogel is the composite aerogel according to any one of claims 1-10 or the composite aerogel prepared by the preparation method according to any one of claims 11-26.

28. The recyclable thermal storage phase change composite material according to claim 27, characterized in that: The mass ratio of the composite aerogel to the phase change material is 1:(0.05-50).

29. The recyclable thermal storage phase change composite material according to claim 27, characterized in that: The phase change material is an organic phase change material.

30. The recyclable thermal storage phase change composite material according to claim 29, characterized in that: The organic phase change material is a water-soluble phase change material and / or a water-insoluble phase change material.

31. The recyclable thermal storage phase change composite material according to claim 29, characterized in that: The organic phase change material is at least one of polyethylene glycol, lauric acid, octadecyl alcohol, and paraffin.

32. The recyclable thermal storage phase change composite material according to claim 27, characterized in that: Under the temperature condition where the phase change material is in a liquid state, the leakage of the phase change material in the recyclable thermal storage phase change composite material is less than 10 wt%.

33. The recyclable thermal storage phase change composite material according to claim 27, characterized in that: Under the temperature condition where the phase change material is in a liquid state, the leakage of the phase change material in the recyclable thermal storage phase change composite material is less than 5 wt%.

34. The recyclable thermal storage phase change composite material according to claim 27, characterized in that: Under the temperature condition where the phase change material is in a liquid state, the leakage of the phase change material in the recyclable thermal storage phase change composite material is less than 2 wt%.

35. A method for preparing a recyclable thermal storage phase change composite material according to any one of claims 27-34, comprising loading the phase change material in the composite aerogel.

36. The method for preparing the recyclable thermal storage phase change composite material according to claim 35, characterized in that: include: The composite aerogel is obtained by the preparation method according to any one of claims 11-26; then the phase change material is loaded into the composite aerogel.

37. The application of the recyclable thermal storage phase change composite material according to any one of claims 27-34 in the fields of building energy conservation, air conditioning systems, waste heat utilization, and solar energy storage.

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