Aerogel thermal insulation energy storage thermal insulation material and a preparation method thereof

Abstract

This invention relates to the field of building energy-saving materials technology, specifically to an aerogel thermal insulation and energy storage material and its preparation method. The material comprises: 5-30 wt% silica aerogel, 30-65 wt% modified expanded perlite, 10-30 wt% phenolic resin, and 20-50 wt% phase change material; and has a three-layer gradient composite structure from the outside to the inside: a surface aerogel thermal insulation layer, an intermediate interface transition layer, and a core energy storage and thermal insulation layer; the modified expanded perlite is surface-modified with γ-aminopropyltriethoxysilane, with an amino grafting amount of 0.5-1.5 mmol / g. This invention solves the interfacial compatibility and phase change leakage problems through APTES chemical bridging modification, and achieves synergistic optimization of thermal insulation and energy storage by combining the three-layer gradient structure. The material has low thermal conductivity, high energy storage density, good cycle stability, and low cost, making it suitable for large-scale applications.

Description

Technical Field

[0001] This invention relates to the field of building energy-saving materials technology, and in particular to an aerogel thermal insulation and energy storage material and its preparation method. Background Technology

[0002] With the increasing demand for energy conservation in buildings and industries, traditional single-function insulation materials can no longer meet the needs of modern thermal management. Especially in the fields of building energy conservation and industrial thermal management, materials are required to have both low thermal conductivity to reduce heat transfer and a certain energy storage capacity to regulate temperature fluctuations.

[0003] Silica aerogel, with its ultra-high porosity (>90%) and nanoscale pore structure, exhibits extremely low thermal conductivity, making it one of the best-performing solid materials known for its thermal insulation properties. However, aerogel materials generally suffer from low mechanical strength, high structural brittleness, and difficulties in processing and molding, which limits their large-scale application in engineering fields.

[0004] On the other hand, phase change materials can absorb or release a large amount of latent heat during the phase change process, exhibiting excellent energy storage performance. However, phase change materials typically suffer from problems such as liquid leakage, poor structural stability, and high thermal conductivity.

[0005] Current technologies attempt to combine aerogels with phase change materials to achieve a combination of thermal insulation and energy storage functions. However, existing technologies still have the following shortcomings: poor interfacial compatibility between aerogels and porous carriers, leading to easy aggregation; difficulty in forming a synergistic system between nanoporous and microporous structures; limited load-bearing capacity of phase change materials, resulting in leakage problems; and poor stability of materials under high temperature or repeated thermal cycling conditions.

[0006] Therefore, it is of great significance to develop a composite energy storage and insulation material with stable structure, excellent thermal insulation performance and high energy storage density. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies, such as poor interfacial compatibility, easy leakage of phase change materials, difficulty in coordinating thermal insulation and energy storage functions, and high material costs, and to provide an aerogel thermal insulation and energy storage material and its preparation method.

[0008] In a first aspect, the present invention provides an aerogel thermal insulation and energy storage material, comprising the following parts by weight:

[0009] 5-30 wt% silica aerogel

[0010] Modified expanded perlite 30-65 wt%

[0011] 10-30 wt% phenolic resin

[0012] Phase change material 20-50 wt%.

[0013] The insulation material is a composite structure, and from the outside to the inside, it includes a surface aerogel insulation layer, an intermediate interface transition layer, and a core energy storage insulation layer.

[0014] The surface aerogel insulation layer accounts for 20-40% of the total thickness of the insulation material, the intermediate interface transition layer accounts for 10-20% of the total thickness of the insulation material, and the core energy storage insulation layer accounts for 40-60% of the total thickness of the insulation material.

[0015] The surface aerogel insulation layer comprises silica aerogel and phenolic resin; and the silica aerogel accounts for 60-80% of the total mass of the layer, while the phenolic resin accounts for 20-40%.

[0016] The intermediate interface transition layer comprises silica aerogel, modified expanded perlite loaded with phase change material, and phenolic resin; and the silica aerogel accounts for 20-40% of the total mass of the intermediate interface transition layer, the modified expanded perlite loaded with phase change material accounts for 40-60% of the total mass of the intermediate interface transition layer, and the remainder is phenolic resin.

[0017] The core energy storage insulation layer comprises modified expanded perlite loaded with phase change material and phenolic resin; and the modified expanded perlite loaded with phase change material accounts for 70-90% of the total mass of the core energy storage insulation layer, and the phenolic resin accounts for 10-30% of the total mass of the core energy storage insulation layer.

[0018] The modified expanded perlite is expanded perlite with a surface modified by γ-aminopropyltriethoxysilane, and the surface of the expanded perlite is grafted with amino functional groups, the grafting amount of which is 0.5-1.5 mmol / g.

[0019] Preferably, the silica aerogel is a hydrophobic silica aerogel particle with a pore size of 20-50 nm, a porosity ≥90%, and a room temperature thermal conductivity ≤0.020 W / (m²). K).

[0020] The modified expanded perlite is made from industrial-grade expanded perlite particles, with a preferred particle size of 0.5-2 mm, a bulk density of 80-120 kg / m³, and a closed-cell rate of ≥70%.

[0021] More preferably, the silane coupling agent is KH-550 or KH-560.

[0022] More preferably, the reinforcing fiber is basalt fiber with a length of 3-6 mm.

[0023] Preferably, the modified expanded perlite is industrial-grade expanded perlite with surface modified by γ-aminopropyltriethoxysilane (APTES), and the surface of the modified expanded perlite is grafted with amino functional groups, the grafting amount of the amino functional groups preferably ranging from 0.8 to 1.2 mmol / g.

[0024] Preferably, the phase change material includes at least one of paraffin wax, stearic acid, lauric acid, and polyethylene glycol, and the phase change temperature range of the phase change material is 20~60℃.

[0025] The thermal insulation material also includes auxiliary agents: 1-5 wt% silane coupling agent and 1-3 wt% reinforcing fiber; the silane coupling agent is KH-550 or KH-560, and the reinforcing fiber is basalt fiber with a length of 3-6 mm.

[0026] In a second aspect, the present invention provides a method for preparing an aerogel thermal insulation and energy storage material, comprising the following steps:

[0027] S1: After heat treatment and activation, expanded perlite is added to an ethanol aqueous solution containing γ-aminopropyltriethoxysilane for surface modification reaction. After the reaction, it is dried to obtain modified expanded perlite with amino functional groups grafted on the surface.

[0028] S2: Heat the phase change material to melt, add the modified expanded perlite obtained in step S1, impregnate and adsorb under vacuum conditions, and then cool to obtain modified expanded perlite loaded with phase change material.

[0029] S3: Prepare the surface aerogel insulation layer slurry, the intermediate interface transition layer slurry, and the core energy storage and heat insulation layer slurry respectively;

[0030] The surface aerogel insulation layer slurry comprises silica aerogel, phenolic resin and solvent;

[0031] The core layer energy storage and heat insulation slurry includes modified expanded perlite, phenolic resin and solvent for loading phase change material obtained in step S2.

[0032] The intermediate interface transition layer slurry comprises silica aerogel, modified expanded perlite loaded with phase change material obtained in step S2, phenolic resin, and solvent.

[0033] S4: The corresponding slurry is laid into the mold in the order of core energy storage and heat preservation layer, intermediate interface transition layer and surface aerogel heat insulation layer, and the thickness of each layer is controlled to meet the preset ratio; then pre-pressing is performed to remove air bubbles, and then segmented hot pressing is performed for curing. After cooling, the aerogel heat insulation and energy storage material is obtained.

[0034] Preferably, in step S1, the heat treatment activation is to first hold at 450°C for 2 hours, and then hold at 550°C for 1 hour;

[0035] The volume ratio of ethanol to deionized water in the ethanol-water solution is 95:5;

[0036] The mass concentration of APTES is 3-8%, the reaction temperature is 70℃, and the reaction time is 3-5h;

[0037] The modified expanded perlite has an amino grafting content of 0.5-1.5 mmol / g, preferably 0.8-1.2 mmol / g.

[0038] Preferably, in step S2, the heating temperature is 10-15°C above the melting point of the phase change material, the vacuum degree is -0.08 to -0.1 MPa, the impregnation and adsorption time is 1-3 h, and the loading of the phase change material is 50-70 wt%.

[0039] In step S4, the thickness ratio of each layer is as follows: the surface aerogel insulation layer accounts for 20-40% of the total thickness, the intermediate interface transition layer accounts for 10-20% of the total thickness, and the core energy storage and heat preservation layer accounts for 40-60% of the total thickness; the pre-compression condition is 0.5-1MPa pressure at room temperature for 10-20 minutes; the segmented hot-press curing condition is: first pre-curing at 80-100℃ for 30-60 minutes, then raising the temperature to 120-150℃, and maintaining the temperature for 2-4 hours under 0.5-2MPa pressure.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] This invention provides an aerogel thermal insulation and energy storage material. It is made by compounding silica aerogel, modified expanded perlite, phenolic resin and phase change material in a specific weight ratio (5-30 wt%, 30-65 wt%, 10-30 wt%, 20-50 wt%), and using low-cost modified expanded perlite as the main filler, which greatly reduces the material cost. At the same time, it utilizes the ultra-low thermal conductivity of aerogel and the high energy storage density of phase change material to provide a basic material system for the synergy of thermal insulation and energy storage.

[0042] This invention provides an aerogel thermal insulation and energy storage material. By employing a three-layer gradient composite structure—consisting of a surface aerogel insulation layer, an intermediate interface transition layer, and a core energy storage insulation layer—it achieves functional zoning and performance synergy: the surface layer, primarily composed of aerogel, achieves ultra-low thermal conductivity, blocking external heat; the core layer, primarily composed of modified expanded perlite loaded with phase change material, achieves high energy storage density and mitigates temperature fluctuations; the intermediate transition layer alleviates differences in interlayer thermal expansion coefficients, prevents interlayer delamination, and constructs a multi-level porous synergistic system, thereby simultaneously optimizing thermal insulation performance, energy storage performance, and structural stability.

[0043] This invention provides an aerogel thermal insulation and energy storage material. By modifying expanded perlite with γ-aminopropyltriethoxysilane (APTES) to graft amino functional groups onto its surface, the grafting amount is controlled at 0.5-1.5 mmol / g. A continuous chemical bridging structure of expanded perlite-APTES-silica aerogel-phenolic resin is constructed between the inorganic filler and the organic matrix, which fundamentally solves the problems of poor interfacial compatibility and powder agglomeration. At the same time, the phase change material in the pores is locked through chemical bonding and steric hindrance effect, which significantly inhibits liquid leakage and greatly improves the mechanical properties and thermal cycling stability of the material. Attached Figure Description

[0044] Figure 1 A schematic diagram of the gradient composite structure of aerogel thermal insulation and energy storage material;

[0045] Figure 2 This is a flowchart of the preparation method of the aerogel thermal insulation and energy storage material of the present invention;

[0046] Figure label:

[0047] 1-Surface aerogel insulation layer; 2-Intermediate interface transition layer; 3-Core energy storage and insulation layer. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0049] This invention discloses an aerogel thermal insulation and energy storage material, the core components of which, by weight percentage, include: 5-30 wt% silica aerogel, 30-65 wt% modified expanded perlite, 10-30 wt% phenolic resin, and 20-50 wt% phase change material.

[0050] By using the above proportions, on the one hand, low-cost modified expanded perlite is used as the main filler, significantly reducing material costs; on the other hand, the ultra-low thermal conductivity of aerogel and the high energy storage density of phase change materials are utilized to achieve synergy between thermal insulation and energy storage. If the aerogel content is below 5 wt%, the thermal insulation performance is insufficient; above 30 wt%, the cost increases significantly and agglomeration is likely. If the modified expanded perlite content is below 30 wt%, the material skeleton strength is insufficient; above 65 wt%, the binder is relatively insufficient, making molding difficult. Phenolic resin below 10 wt% cannot effectively bind the components; above 30 wt%, the porosity decreases, affecting thermal insulation and energy storage. Phase change material below 20 wt% has too low energy storage density; above 50 wt%, leakage is likely.

[0051] More specifically, the thermal insulation material has a three-layer gradient composite structure, consisting of a surface aerogel insulation layer 1, an intermediate interface transition layer 2, and a core energy storage insulation layer 3, arranged from the outside to the inside. For example... Figure 1 As shown, the surface aerogel insulation layer accounts for 20-40% of the total material thickness, the intermediate interface transition layer accounts for 10-20%, and the core energy storage and insulation layer accounts for 40-60%.

[0052] This gradient structure achieves functional zoning: the surface layer, primarily composed of aerogel, plays a crucial role in insulation due to its ultra-low thermal conductivity, blocking external heat transfer; the core layer, primarily composed of modified expanded perlite loaded with phase change material, achieves temperature regulation for high energy storage density; the intermediate transition layer mitigates the difference in thermal expansion coefficients between layers through gradual component changes, preventing interlayer delamination and cracking, while simultaneously constructing a multi-level pore synergistic system of "nanopores-micropores" to further optimize insulation and energy storage performance. The thickness ratio is critical: a surface layer that is too thin results in poor insulation, while one that is too thick results in insufficient energy storage volume; a core layer that is too thin has insufficient energy storage capacity, while one that is too thick increases interfacial stress and easily leads to delamination; an intermediate layer that is too thin cannot effectively transition, while one that is too thick sacrifices the volume of the functional layers.

[0053] The modified expanded perlite is an industrial-grade expanded perlite surface-modified with γ-aminopropyltriethoxysilane (APTES). Its surface is grafted with amino functional groups at a rate of 0.5-1.5 mmol / g, preferably 0.8-1.2 mmol / g. The siloxane groups of APTES undergo a condensation reaction with the hydroxyl groups on the expanded perlite surface, grafting active amino functional groups onto the expanded perlite surface. These amino groups can then covalently bond with the silanol groups on the silica aerogel surface and the hydroxymethyl groups on the phenolic resin, forming a continuous chemically bridged interface structure of "expanded perlite—APTES—silica aerogel—phenolic resin". This structure fundamentally solves the interfacial compatibility problem between inorganic fillers and organic matrices, inhibits powder agglomeration and phase separation, and simultaneously locks the phase change material within the pores through chemical bonding, significantly reducing the risk of leakage. When the amount of amino grafting is less than 0.5 mmol / g, the interface modification effect is insufficient, and the mechanical properties and anti-leakage ability are significantly reduced; when it is more than 1.5 mmol / g, the excessive APTES will cause powder agglomeration, increasing the cost while the performance improvement is limited.

[0054] The silica aerogel is preferably hydrophobic silica aerogel particles with a pore size of 20-50 nm, a porosity ≥90%, and a room temperature thermal conductivity ≤0.020 W / (m·K). This nanoporous structure can effectively suppress gas convection heat transfer and solid heat conduction, which is the key to achieving ultra-low thermal conductivity.

[0055] The modified expanded perlite is made from industrial-grade expanded perlite particles with a particle size of 0.5-2 mm, a bulk density of 80-120 kg / m³, and a closed-cell rate of ≥70%. This particle size range ensures good load-bearing capacity and is also beneficial for molding and processing; the high closed-cell rate helps to reduce the overall thermal conductivity of the material.

[0056] The phase change material is selected from at least one of paraffin wax, stearic acid, lauric acid, and polyethylene glycol, with a phase change temperature range of 20-60℃. This temperature range covers typical application scenarios for building energy conservation and industrial thermal management, and can be adapted to meet actual needs.

[0057] As a further preferred embodiment, the thermal insulation material may further include auxiliary agents: 1-5 wt% silane coupling agent and 1-3 wt% reinforcing fiber. The silane coupling agent (KH-550 or KH-560) can further enhance the interfacial bonding force between the inorganic filler and the phenolic resin; the reinforcing fiber (basalt fiber, 3-6 mm in length) can significantly improve the flexural strength and impact resistance of the material, and improve the inherent brittleness of aerogel.

[0058] This embodiment discloses a method for preparing an aerogel thermal insulation and energy storage material, such as... Figure 2 As shown, it includes the following steps:

[0059] S1: Preparation of modified expanded perlite. Industrial-grade expanded perlite particles were activated by heat treatment. The activation process involved holding the particles at 450℃ for 2 hours, followed by holding them at 550℃ for 1 hour to remove adsorbed water and hydroxyl groups from the surface and increase active sites. The activated expanded perlite was then added to an ethanol-water solution of APTES (ethanol:deionized water = 95:5, volume ratio), with an APTES concentration of 3-8%. The solution was stirred at 70℃ for 3-5 hours to allow the APTES to fully react with the hydroxyl groups on the perlite surface. After the reaction, the perlite was dried at 105℃ to obtain modified expanded perlite with an amino grafting amount of 0.5-1.5 mmol / g. In this step, the reaction temperature and time directly affect the grafting efficiency: too low a temperature or too short a time results in insufficient grafting, while too high a temperature or too long a time may cause APTES self-aggregation. A grafting amount of 0.8-1.2 mmol / g is preferred to balance modification effect and cost.

[0060] S2: Vacuum loading of the phase change material. The phase change material is placed in a reactor and heated to 10-15°C above its melting point to completely melt it. The modified expanded perlite obtained in step S1 is added, and after stirring evenly, the vacuum system is turned on, controlling the system vacuum degree to -0.08 to -0.1 MPa. Vacuum impregnation adsorption is performed at a constant temperature for 1-3 hours. The vacuum negative pressure efficiently presses the molten phase change material into the micron-sized pores of the modified expanded perlite, achieving a high loading (50-70 wt%) and robust physical encapsulation. After adsorption is complete, the mixture is cooled to room temperature to obtain modified expanded perlite loaded with the phase change material.

[0061] S3: Preparation of gradient structure slurry. Prepare slurry for the surface aerogel insulation layer 1, the intermediate interface transition layer 2, and the core energy storage and insulation layer 3, respectively. Surface slurry: Add silica aerogel, phenolic resin, and silane coupling agent to anhydrous ethanol solvent according to the specified ratio, and stir for 30-60 min to obtain a slurry with a solid content of 30-50%. Core slurry: Add modified expanded perlite loaded with phase change material, phenolic resin, and silane coupling agent to anhydrous ethanol according to the specified ratio, and stir for 20-40 min to obtain a slurry with a solid content of 40-60%. Intermediate layer slurry: Add silica aerogel, modified expanded perlite loaded with phase change material, phenolic resin, silane coupling agent, and reinforcing fibers to anhydrous ethanol according to the specified ratio, and stir for 30-50 min to obtain a slurry with a solid content of 35-55%. Controlling the solid content of each layer of slurry is crucial to the quality of subsequent lay-up and curing: if it is too high, the slurry will be too viscous and difficult to spread evenly; if it is too low, the drying shrinkage will be large and cracks will easily occur.

[0062] S4: Gradient Layup and Hot-Pressure Curing. Following the sequence of core energy storage and insulation layer 3, intermediate interface transition layer 2, and surface aerogel insulation layer 1, the corresponding slurry is evenly laid into a flat mold, controlling the thickness of each layer to meet the preset ratio (surface layer 20-40%, intermediate layer 10-20%, core layer 40-60%). After laying, the mold is placed in a flat vulcanizing machine and pre-pressed at room temperature under 0.5-1 MPa pressure for 10-20 min to remove air bubbles and improve interlayer bonding density. Subsequently, segmented hot-curing is performed: pre-curing at 80-100℃ for 30-60 min to initially cross-link the phenolic resin and fix the structure of each layer; then heating to 120-150℃ and holding at 0.5-2 MPa pressure for 2-4 h to fully cross-link and cure the resin, forming a stable three-dimensional network structure. Segmented curing effectively avoids internal stress and air bubble generation caused by sudden temperature increases, ensuring interlayer bonding strength. After curing, allow it to cool naturally to room temperature, then demold to obtain the aerogel thermal insulation and energy storage material.

[0063] The overall technical advantages of the above preparation method are as follows: the interfacial compatibility problem is solved through APTES chemical bridging modification; high-capacity encapsulation of phase change materials is achieved through vacuum loading; and a multi-layered structure with synergistic functions is constructed through gradient layup and segmented hot pressing. This method offers controllable process parameters, eliminates the need for complex equipment such as supercritical drying, and uses industrial-grade perlite as the main raw material, resulting in low cost and suitability for large-scale industrial production.

[0064] The technical solutions and beneficial effects of the present invention are further illustrated below with reference to specific embodiments and comparative examples, but are not intended to limit the scope of the present invention. Experimental methods not specifically described in the embodiments are generally carried out under conventional conditions or according to the conditions recommended by the raw material manufacturer. Unless otherwise stated, all raw materials used are commercially available industrial-grade raw materials.

[0065] Table 1 is a list of raw materials.

[0066]

[0067] Example 1

[0068] This embodiment provides a gradient-structured aerogel-based composite energy storage and insulation material. Its core components, by weight percentage, are: 15 wt% silica aerogel, 40 wt% modified expanded perlite, 20 wt% phenolic resin, and 25 wt% phase change paraffin wax. The three-layer gradient structure has the following thickness proportions: surface layer 30%, middle layer 15%, and core layer 55%. The modified expanded perlite has an amino grafting amount of 1.0 mmol / g and a particle size of 0.5-2 mm; the silica aerogel has a pore size of 20-50 nm and a porosity of 92%; and the phase change paraffin wax has a phase change temperature of 25℃.

[0069] The preparation steps are as follows:

[0070] S1: Take industrial-grade expanded perlite (0.5-2 mm), place it in a muffle furnace, keep it at 450℃ for 2 h, and then keep it at 550℃ for 1 h to activate it; then add an ethanol-water solution of APTES (ethanol:water = 95:5, APTES concentration 5 wt%), react at 70℃ for 4 h, and dry at 105℃ to constant weight to obtain modified expanded perlite with an amino grafting amount of 1.0 mmol / g.

[0071] S2: Heat paraffin wax to 60℃ until completely melted, add modified expanded perlite, stir evenly, and then impregnate at a constant temperature of -0.095MPa vacuum for 2 hours. Cool to room temperature to obtain modified expanded perlite with a paraffin wax loading of 60 wt%.

[0072] S3: Slurry preparation. Surface slurry: 70 parts silica aerogel, 30 parts phenolic resin, and 3 parts KH-550 coupling agent were added to anhydrous ethanol and stirred for 40 min to obtain a surface slurry with a solid content of 40%. Intermediate slurry: 30 parts silica aerogel, 50 parts paraffin-loaded modified expanded perlite, 20 parts phenolic resin, 3 parts KH-550 coupling agent, and 2 parts basalt fiber were added to anhydrous ethanol and stirred for 40 min to obtain an intermediate slurry with a solid content of 45%. Core slurry: 80 parts paraffin-loaded modified expanded perlite, 20 parts phenolic resin, and 2 parts KH-550 coupling agent were added to anhydrous ethanol and stirred for 30 min to obtain a core slurry with a solid content of 50%.

[0073] S4: The core layer, intermediate layer and surface layer are laid into the mold in the order of core layer, intermediate layer and surface layer, and the thickness ratio of each layer is controlled to be 55%, 15% and 30% respectively; pre-pressed at room temperature at 0.8 MPa for 15 min, then pre-cured at 90℃ for 45 min, cured at 130℃ and 1.2 MPa pressure for 3 h, cooled and demolded to obtain composite energy storage and heat preservation material.

[0074] Example 2

[0075] The difference between this embodiment and Example 1 is as follows: the core components, by weight percentage, are: 5 wt% silica aerogel, 65 wt% modified expanded perlite, 10 wt% phenolic resin, and 20 wt% phase change paraffin; the thickness ratio of the three layers is: surface layer 20%, middle layer 20%, and core layer 60%; the amino grafting amount of the modified expanded perlite is 0.8 mmol / g. The remaining formulation and preparation steps are the same as in Example 1.

[0076] The purpose of this embodiment is to verify the feasibility of the lower limit of the formulation ratio (5 wt% aerogel, 10 wt% phenolic resin, 20 wt% phase change material) and the preferred value of the lower limit of grafting amount (0.8 mmol / g) of the present invention. At the same time, in conjunction with the lower limit parameters of the gradient structure (20% for the surface layer and 60% for the core layer), it is confirmed that the formulation ratio and lower limit of the structure defined by the present invention can still ensure that the material has qualified thermal insulation, energy storage, mechanical and stability properties, and avoid the application range being limited due to the parameter lower limit design being too high.

[0077] Example 3

[0078] The difference between this embodiment and Example 1 is as follows: the core components, by weight percentage, are: 30 wt% silica aerogel, 30 wt% modified expanded perlite, 15 wt% phenolic resin, and 25 wt% phase change paraffin; the thickness ratio of the three layers is: surface layer 40%, middle layer 10%, and core layer 50%; the amino grafting amount of the modified expanded perlite is 1.2 mmol / g. The remaining formulation and preparation steps are the same as in Example 1.

[0079] The purpose of this embodiment is to verify the rationality of the upper limit of the formulation ratio (30 wt% aerogel) and the preferred value of the upper limit of grafting amount (1.2 mmol / g) of the present invention. Combined with the upper limit parameters of the gradient structure (40% for the surface layer and 10% for the middle layer), it verifies the effect of improving the thermal insulation performance of the material under high aerogel ratio and high grafting rate. At the same time, it confirms that the upper limit of the parameters will not cause negative problems such as powder agglomeration and phase separation, and clarifies the upper limit boundary of the formulation and modification parameters.

[0080] Example 4

[0081] The difference between this embodiment and Example 1 is that: stearic acid is used as the phase change material, with a phase change temperature of 25°C and a dosage of 50 wt%; the dosage of modified expanded perlite is 30 wt%, silica aerogel is 10 wt%, and phenolic resin is 10 wt%. The remaining formulations and preparation steps are the same as in Example 1.

[0082] The core of this embodiment is to verify the adaptability of phase change materials. Paraffin wax in the basic embodiment 1 is replaced with stearic acid, and a high loading of phase change material (50 wt%) is used to verify the universality of the technical solution of the present invention for different organic phase change materials (paraffin wax, stearic acid, lauric acid, polyethylene glycol). At the same time, it is confirmed that good shaping effect can still be achieved under high phase change loading, with no obvious leakage, which reflects the adjustability of the present invention in terms of energy storage density.

[0083] Example 5

[0084] The difference between this embodiment and Example 1 is that the amount of amino grafting in the modified expanded perlite is 0.5 mmol / g, the concentration of APTES ethanol aqueous solution is 3 wt%, and the reaction time is 3 h. The remaining formulation and preparation steps are the same as in Example 1.

[0085] The purpose of this embodiment is to verify the performance boundary of the absolute lower limit of amino grafting amount (0.5 mmol / g) of the present invention, and in conjunction with the lower limit of APTES concentration (3 wt%) and the lower limit of reaction time (3 h), to clarify the performance change trend of the material when the grafting amount reaches the lower limit (slight oil seepage, slight decrease in latent heat retention rate), to provide experimental basis for limiting the grafting amount parameter range, and to explain the rationality of the lower limit of grafting amount (below this value, the performance is greatly degraded).

[0086] Example 6

[0087] The difference between this embodiment and Example 1 is that the amount of amino grafting in the modified expanded perlite is 1.5 mmol / g, the concentration of APTES ethanol aqueous solution is 8 wt%, and the reaction time is 5 h. The remaining formulation and preparation steps are the same as in Example 1.

[0088] The purpose of this embodiment is to verify the performance boundary of the absolute upper limit of the amino grafting amount (1.5 mmol / g) of the present invention, combined with the upper limit of APTES concentration (8 wt%) and the upper limit of reaction time (5 h), to confirm that the material can still maintain good comprehensive performance (no leakage, qualified mechanical properties) when the grafting amount reaches the upper limit. At the same time, it provides a basis for limiting the range of grafting amount parameters, indicating that the grafting amount does not need to be too high (too high a grafting amount will easily lead to an increase in modification cost and no significant improvement in performance).

[0089] Comparative Example 1

[0090] This comparative example simulates the existing binary phenolic resin / aerogel homogeneous composite system without gradient structure, modified expanded perlite, or phase change materials. The formulation is: 60 wt% silica aerogel and 40 wt% phenolic resin. The system is conventionally mixed and then hot-pressed for curing, with the curing process being the same as in Example 1.

[0091] Comparative Example 2

[0092] This comparative example simulates the existing binary phenolic resin / perlite homogeneous composite system, which has no gradient structure and no aerogel component. The formulation is: 70 wt% unmodified expanded perlite, 30 wt% phenolic resin, and 25 wt% loaded phase change paraffin. It is mixed by conventional stirring and then hot-pressed for curing. The curing process is the same as that in Example 1.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that the expanded perlite was not surface modified with APTES, while the rest of the formulation, structure, and preparation steps are completely consistent with Example 1.

[0095] Comparative Example 4

[0096] The difference between this comparative example and Example 1 is that a homogeneous composite structure is adopted, without a three-layer gradient design. All components are directly mixed evenly according to the proportions of Example 1 and then hot-pressed and cured. The remaining preparation steps are the same as those in Example 1.

[0097] Comparative Example 5

[0098] The difference between this comparative example and Example 1 is that the amount of amino grafting in the modified expanded perlite is 0.3 mmol / g (lower than the lower limit specified in this invention), the concentration of APTES ethanol aqueous solution is 1 wt%, and the rest of the formulation, structure, and preparation steps are the same as in Example 1.

[0099] Comparative Example 6

[0100] The difference between this comparative example and Example 1 is that the amount of amino grafting in the modified expanded perlite is 2.0 mmol / g (higher than the upper limit specified in this invention), the concentration of APTES ethanol aqueous solution is 10 wt%, and the rest of the formulation, structure, and preparation steps are the same as in Example 1.

[0101] Comparative Example 7

[0102] The difference between this comparative example and Example 1 is that the expanded perlite was conventionally modified using the silane coupling agent KH-550, rather than being directionally grafted with APTES. The rest of the formulation, structure, and preparation steps are the same as in Example 1.

[0103] Comparative Example 8

[0104] The difference between this comparative example and Example 1 is that the thickness ratio of the three-layer gradient structure is: 10% for the surface layer, 5% for the middle layer, and 85% for the core layer (which is beyond the scope of this invention). The remaining formulation and preparation steps are the same as in Example 1.

[0105] Performance Tests and Results

[0106] The following performance tests were performed on the thermal insulation materials prepared in Examples 1-6 and Comparative Examples 1-8:

[0107] Thermal conductivity: The transient plane heat source method (TPS) was used to test the thermal conductivity at 25℃, in accordance with GB / T 10294-2008.

[0108] Phase change latent heat and phase change temperature: Differential scanning calorimetry (DSC) was used for testing according to GB / T 19466-2004, with a heating rate of 5℃ / min and a test temperature range of 0-80℃.

[0109] Mechanical properties: The compressive strength was tested using a universal testing machine according to GB / T 8813-2008 at a loading rate of 2 mm / min; the flexural strength was tested according to GB / T 8812-2008 at a span of 100 mm and a loading rate of 5 mm / min.

[0110] Thermal cycling stability: The sample is placed in a high and low temperature alternating test chamber and subjected to thermal cycling between 0℃ and 60℃ for 1000 cycles. The latent heat of phase change before and after the cycle is tested, the latent heat retention rate is calculated, and the sample is observed for phase change leakage.

[0111] Amino grafting amount: The amino grafting amount on the surface of modified expanded perlite was tested by acid-base titration.

[0112] The test results are summarized in the table below:

[0113] Table 2 is a summary table of test data for Examples 1-6 and Comparative Examples 1-8.

[0114]

[0115] The test results show that:

[0116] The gradient structure composite thermal insulation materials prepared in Examples 1-6 of this invention simultaneously achieve ultra-low thermal conductivity (minimum 0.020 W / (m·K), high latent heat of phase change (maximum 178 J / g), excellent mechanical properties (compressive strength ≥0.35 MPa), and cyclic stability (latent heat retention ≥92% after 1000 cycles). Furthermore, except for slight oil seepage in Example 5 (absolute lower limit of grafting amount), no significant phase change leakage was observed in the others. The overall performance is far superior to the existing technologies in the comparative examples.

[0117] The pure aerogel / phenolic resin system of Comparative Example 1, although having a low thermal conductivity of 0.022 W / (m·K), lacks energy storage function (late heat is 0) and exhibits poor mechanical strength (compressive strength is only 0.21 MPa), exhibiting high brittleness. The pure perlite / phenolic resin system of Comparative Example 2, while possessing energy storage function (late heat 118 J / g), has extremely high thermal conductivity (0.058 W / (m·K), poor thermal insulation performance, severe phase change leakage, and extremely poor cycle stability (late heat retention rate is only 72.3%), thus confirming the necessity of the functional synergistic design of this invention.

[0118] Comparative Example 3 did not undergo APTES interface modification, Comparative Example 5 had an excessively low grafting amount of 0.3 mmol / g, and Comparative Example 7 was modified with conventional KH-550. All of these examples showed problems such as poor interfacial compatibility, decreased mechanical strength, severe phase change leakage, and significant decrease in cycle stability, which confirms the core role of APTES directional modification and chemical bridging interface design in this invention.

[0119] Comparative Example 4 has no gradient structure and is a homogeneous mixture, while Comparative Example 8 has a gradient thickness that exceeds the limit (only 10% for the surface layer and 85% for the core layer). Both examples show problems such as decreased thermal insulation performance, interface stress concentration, and reduced cycle stability, which confirms the key role of the gradient structure design and thickness ratio limit in this invention.

[0120] Comparative Example 6 had an excessively high grafting amount (2.0 mmol / g), resulting in powder agglomeration due to over-modification and a certain degree of performance decline (latent heat retention rate of 89.7%, lower than that of the Example), which confirms the rationality of limiting the grafting amount range (0.5-1.5 mmol / g) in this invention.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aerogel thermal insulation and energy storage material, characterized in that, The components include the following parts by weight: 5-30 wt% silica aerogel Modified expanded perlite 30-65 wt% 10-30 wt% phenolic resin Phase change material 20-50 wt% The insulation material is a composite structure, and from the outside to the inside, it includes a surface aerogel insulation layer, an intermediate interface transition layer, and a core energy storage insulation layer. The surface aerogel insulation layer accounts for 20-40% of the total thickness of the insulation material, the intermediate interface transition layer accounts for 10-20% of the total thickness of the insulation material, and the core energy storage insulation layer accounts for 40-60% of the total thickness of the insulation material. The surface aerogel insulation layer comprises silica aerogel and phenolic resin; and the silica aerogel accounts for 60-80% of the total mass of the layer, while the phenolic resin accounts for 20-40%. The intermediate interface transition layer comprises silica aerogel, modified expanded perlite loaded with phase change material, and phenolic resin; and the silica aerogel accounts for 20-40% of the total mass of the intermediate interface transition layer, the modified expanded perlite loaded with phase change material accounts for 40-60% of the total mass of the layer, and the remainder is phenolic resin. The core energy storage and insulation layer comprises modified expanded perlite loaded with phase change material and phenolic resin; wherein the modified expanded perlite loaded with phase change material accounts for 70-90% of the total mass of the layer, and the phenolic resin accounts for 10-30%; The modified expanded perlite is expanded perlite with a surface modified by γ-aminopropyltriethoxysilane, and the surface of the expanded perlite is grafted with amino functional groups, the grafting amount of which is 0.5-1.5 mmol / g.

2. The aerogel thermal insulation and energy storage material according to claim 1, characterized in that, The silica aerogel is a hydrophobic silica aerogel particle with a pore size of 20-50 nm, a porosity of ≥90%, and a room temperature thermal conductivity of ≤0.020 W / (m·K). The modified expanded perlite is made from industrial-grade expanded perlite particles with a particle size of 0.5-2 mm, a bulk density of 80-120 kg / m³, and a closed-cell rate of ≥70%.

3. The aerogel thermal insulation and energy storage material according to claim 1, characterized in that, The phase change material includes at least one of paraffin wax, stearic acid, lauric acid, and polyethylene glycol, and the phase change temperature range of the phase change material is 20-60℃.

4. The aerogel thermal insulation and energy storage material according to claim 1, characterized in that, The thermal insulation material also includes auxiliary agents: 1-5 wt% silane coupling agent and 1-3 wt% reinforcing fiber; the silane coupling agent is KH-550 or KH-560, and the reinforcing fiber is basalt fiber with a length of 3-6 mm.

5. The aerogel thermal insulation and energy storage material according to claim 1, characterized in that, The amount of amino functional group grafted is 0.8-1.2 mmol / g.

6. The method for preparing the aerogel thermal insulation and energy storage material according to any one of claims 1-5, characterized in that, Includes the following steps: S1: After heat treatment and activation, expanded perlite is added to an ethanol aqueous solution containing γ-aminopropyltriethoxysilane for surface modification reaction. After the reaction, it is dried to obtain modified expanded perlite with amino functional groups grafted on the surface. S2: Heat the phase change material to melt, add the modified expanded perlite obtained in step S1, impregnate and adsorb under vacuum conditions, and then cool to obtain modified expanded perlite loaded with phase change material. S3: Prepare the surface aerogel insulation layer slurry, the intermediate interface transition layer slurry, and the core energy storage and heat insulation layer slurry respectively; The surface aerogel insulation layer slurry comprises silica aerogel, phenolic resin and solvent; The core layer energy storage and heat insulation slurry includes modified expanded perlite, phenolic resin and solvent for loading phase change material obtained in step S2. The intermediate interface transition layer slurry comprises silica aerogel, modified expanded perlite loaded with phase change material obtained in step S2, phenolic resin, and solvent. S4: The corresponding slurry is laid into the mold in the order of core energy storage and heat preservation layer, intermediate interface transition layer and surface aerogel heat insulation layer, and the thickness of each layer is controlled; then pre-pressing is performed to remove air bubbles, and then segmented hot pressing is performed for curing. After cooling, the aerogel heat insulation and energy storage material is obtained.

7. The method for preparing the aerogel thermal insulation and energy storage material according to claim 6, characterized in that, In step S1, the heat treatment activation involves first holding at 450℃ for 2 hours, and then holding at 550℃ for 1 hour. The volume ratio of ethanol to deionized water in the ethanol-water solution is 95:5; The mass concentration of APTES is 3-8%, the reaction temperature is 70℃, and the reaction time is 3-5h; The modified expanded perlite has an amino grafting amount of 0.5-1.5 mmol / g.

8. The method for preparing the aerogel thermal insulation and energy storage material according to claim 6, characterized in that, In step S2, the heating temperature is 10-15°C above the melting point of the phase change material, the vacuum degree is -0.08~-0.1MPa, the impregnation and adsorption time is 1-3h, and the loading of the phase change material is 50-70wt%.

9. The method for preparing the aerogel thermal insulation and energy storage material according to claim 6, characterized in that, In step S4, the thickness ratio of each layer is as follows: the surface aerogel insulation layer accounts for 20-40% of the total thickness, the intermediate interface transition layer accounts for 10-20% of the total thickness, and the core energy storage and insulation layer accounts for 40-60% of the total thickness.

10. The method for preparing the aerogel thermal insulation and energy storage material according to claim 6, characterized in that, In step S4, the pre-compression conditions are: 0.5~1MPa pressure at room temperature for 10~20min; the segmented hot-press curing conditions are: first pre-curing at 80~100℃ for 30~60min, then raising the temperature to 120~150℃ and keeping it at 0.5~2MPa pressure for 2~4h.

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