Organic-inorganic multi-component hybrid phase change microcapsule energy storage material and preparation method thereof

Abstract

The invention discloses an organic-inorganic multi-component hybrid phase change microcapsule energy storage material and a preparation method thereof, and relates to the technical field of phase change energy storage materials. The energy storage material comprises a multi-component organic phase change core material and an organic-inorganic multi-component hybrid shell material, the multi-component organic phase change core material is composed of PEG4000, PEG6000, lauric acid and Span-80 according to specific parts by mass, the organic-inorganic multi-component hybrid shell material is composed of a melamine-formaldehyde prepolymer, nano modified particles, hexamethylenediamine and sodium dodecyl benzene sulfonate according to specific parts by mass, and the nano modified particles are a mixture of KH-550 modified nano SiO2 and KH-570 modified nano Al2O3. The phase change performance of the prepared energy storage material adapts to multiple scenes, and the energy storage material is excellent in heat conduction and mechanical performance, good in leakage prevention and cycling stability and capable of being widely applied to the field of phase change energy storage.

Description

Technical Field

[0001] This invention relates to the field of phase change energy storage materials technology, and in particular to an organic-inorganic multi-component hybrid phase change microcapsule energy storage material and its preparation method. Background Technology

[0002] Phase change microcapsules, with their core structure of encapsulating phase change core materials in a shell, effectively solve the key problems of easy leakage and poor fluidity in traditional phase change materials, and have become core energy storage materials in fields such as building energy conservation, electronic thermal control, and power battery thermal management.

[0003] However, existing phase change microcapsule technology still faces the following major technical problems in practical applications, severely limiting its adaptability to multiple scenarios and long-term stability: 1. Significantly limited temperature range: Existing products mostly use a single organic phase change core material (such as polyethylene glycol 6000, paraffin, etc.), with a fixed phase change temperature, which cannot meet the needs of different scenarios for differentiated temperature ranges. Moreover, a single core material is prone to phase change latent heat decay due to purity fluctuations, further reducing energy storage efficiency; 2. Inherent contradictions in shell material performance: Pure organic shell materials (such as melamine-formaldehyde resin, polyurethane) have good film-forming properties, but weak leakage prevention ability and low thermal conductivity, making it difficult to meet the rapid heat dissipation requirements of high-power equipment. On the other hand, pure inorganic shell materials (such as silicon dioxide, titanium dioxide) have good thermal conductivity and... While the mechanical strength is slightly improved, it suffers from high mechanical brittleness (compressive strength ≤10MPa) and loose bonding between the core and shell. After 500 cycles of thermal cycling, the latent heat retention rate is ≤80%, making it unsuitable for long-term repeated use. 3. The preparation process has poor adaptability. Traditional in-situ polymerization methods can only achieve the coating of organic shell materials, making it difficult to introduce inorganic nanoparticles to improve thermal conductivity and mechanical properties. Although the sol-gel method can prepare inorganic shell materials, it is prone to phase change core material swelling due to solvent action, and inorganic particles tend to agglomerate during the reaction, making it difficult to achieve uniform coating. There is currently no process solution that can simultaneously accommodate the uniform dispersion of multi-component core materials and the synergistic coating of organic-inorganic shell materials, which cannot fundamentally solve the problems of narrow temperature range of core materials and unbalanced shell material performance.

[0004] In view of the above, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an organic-inorganic multi-component hybrid phase change microcapsule energy storage material and its preparation method, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides an organic-inorganic multi-component hybrid phase change microcapsule energy storage material, comprising a multi-component organic phase change core material and an organic-inorganic multi-component hybrid shell material covering the surface of the multi-component organic phase change core material;

[0008] The multi-component organic phase change core material, by mass, comprises 50-60 parts PEG4000, 20-30 parts PEG6000, 10-20 parts lauric acid, and 1-3 parts Span-80.

[0009] The organic-inorganic multi-component hybrid shell material, by weight, comprises 60-70 parts melamine-formaldehyde prepolymer, 25-35 parts nano-modified particles, 2-5 parts hexamethylenediamine, and 1-3 parts sodium dodecylbenzenesulfonate (SDBS).

[0010] The modified nanoparticles are obtained by mixing nano-SiO2 modified with KH-550 silane coupling agent and nano-Al2O3 modified with KH-570 silane coupling agent at a mass ratio of 15-20:10-15.

[0011] As a further preferred embodiment of the present invention, the mass ratio of the multi-component organic phase change core material to the organic-inorganic multi-component hybrid shell material is 6-8:1.

[0012] As a further preferred embodiment of the present invention, the method for preparing the melamine-formaldehyde prepolymer includes the following steps:

[0013] Melamine and formaldehyde were mixed in a 35-40% aqueous solution of formaldehyde at a molar ratio of 1:3. Triethanolamine was then added to adjust the pH to 8. The mixture was stirred at 60-65°C until the melamine dissolved, thus obtaining the melamine-formaldehyde prepolymer.

[0014] The multi-component organic phase change core material of this invention is composed of PEG4000, PEG6000 and lauric acid in a specific ratio. After mixing, it can form a continuous phase change temperature range through solid-liquid phase changes in sequence, breaking through the limitation of temperature regulation range of single core material. At the same time, after the components are melted and uniformly mixed, Span-80, as an emulsifier, can reduce the interfacial tension of the components, ensuring the uniformity and stability of the core material system and avoiding the energy storage efficiency decay caused by component separation. This lays the foundation for the material to adapt to the energy storage needs of multiple scenarios.

[0015] This invention utilizes an organic-inorganic multi-component hybrid shell material to optimize performance through functional complementarity: melamine-formaldehyde prepolymer, as the organic phase, can be cross-linked and cured with hexamethylenediamine to form a dense film structure, providing basic sealing for the core material and preventing leakage; nano-SiO2 and nano-Al2O3 modified with KH-550 and KH-570 silane coupling agents, as the inorganic phase, can, on the one hand, combine with the hydroxyl groups on the surface of inorganic particles and the active groups of the organic phase, respectively, enhancing the bonding force between the core and shell, solving the problems of high brittleness and loose interface of pure inorganic shell materials; on the other hand, the excellent thermal conductivity of the inorganic particles themselves can improve the overall thermal conductivity efficiency of the shell material, compensating for the poor thermal conductivity of pure organic shell materials; sodium dodecylbenzenesulfonate (SDBS) acts as a dispersant, promoting the uniform distribution of the organic and inorganic phases in the pre-dispersion liquid, avoiding particle agglomeration, and ensuring the uniformity of the shell material structure.

[0016] This invention also provides a method for preparing the above-mentioned organic-inorganic multi-component hybrid phase change microcapsule energy storage material, comprising the following steps:

[0017] (1) Preparation of multi-component organic phase change core material: PEG4000, PEG6000 and lauric acid were melted and stirred at 70-80℃, and Span-80 was added and stirred continuously to obtain core material melt liquid;

[0018] (2) Preparation of modified nanoparticles: Nano-SiO2 was modified with KH-550 silane coupling agent, and obtained by centrifugation, washing and drying. Nano-Al2O3 was modified with KH-570 silane coupling agent, and obtained by centrifugation, washing and drying. The KH-570 silane coupling agent modified nano-Al2O3 was mixed to obtain modified nanoparticles.

[0019] (3) Preparation of organic-inorganic multi-component hybrid shell material predispersant: The melamine-formaldehyde prepolymer, modified nanoparticles, and sodium dodecylbenzenesulfonate were added to water and ultrasonically dispersed and mechanically stirred to obtain organic-inorganic multi-component hybrid shell material predispersant.

[0020] (4) In-situ polymerization method for preparing phase change microcapsules: The core material melt is dropped into the organic-inorganic multi-component hybrid shell material pre-dispersion liquid to form an O / W emulsion. The pH is adjusted to 4.0-4.5, hexamethylenediamine is added, and polymerization is carried out at 85-90℃ for 4-6 hours. After centrifugation, washing and drying, the organic-inorganic multi-component hybrid phase change microcapsule energy storage material is obtained.

[0021] As a further preferred embodiment of the present invention, the preparation method of the KH-550 silane coupling agent modified nano-SiO2 includes the following steps:

[0022] In a dispersion medium, nano-SiO2 is modified using KH-550 silane coupling agent at 60-70℃. After separation, washing, and drying, the KH-550 silane coupling agent modified nano-SiO2 is obtained.

[0023] As a further preferred embodiment of the present invention, the dispersion medium used to prepare the KH-550 silane coupling agent modified nano-SiO2 is an ethanol-water mixture with a mass ratio of 9:1; the modification time is 2-3 hours.

[0024] As a further preferred embodiment of the present invention, the mass concentration of nano-SiO2 in the dispersion is 5-8%; and the KH-550 is 1-3% of the mass of nano-SiO2.

[0025] As a further preferred embodiment of the present invention, the preparation method of the KH-570 silane coupling agent modified nano-Al2O3 includes the following steps:

[0026] In a dispersion medium, nano-Al2O3 was modified using KH-570 silane coupling agent at 70-80℃. After separation, washing, and drying, the KH-570 silane coupling agent-modified Al2O3 was obtained.

[0027] As a further preferred embodiment of the present invention, the dispersion medium used for preparing KH-570 silane coupling agent modified nano-Al2O3 is an ethanol-water mixture with a mass ratio of 8:2; the modification time is 2-3 hours.

[0028] As a further preferred embodiment of the present invention, the KH-570 is 1-3% of the mass of nano-Al2O3; the mass concentration of nano-Al2O3 in the dispersion is 5-8%.

[0029] This invention employs an in-situ polymerization method, which involves dripping molten core material into a pre-dispersed shell material to form a stable O / W emulsion. Adjusting the pH value to 4.0-4.5 triggers the cross-linking reaction of melamine-formaldehyde prepolymer, which gradually solidifies on the surface of the core material to form a hybrid shell material, achieving precise encapsulation of the core material and the shell material. At the same time, the heat preservation polymerization temperature of 85-90℃ ensures that the cross-linking reaction proceeds fully and avoids thermal decomposition of the core material due to excessive temperature, ultimately forming a phase change microcapsule energy storage material with complete structure and stable performance.

[0030] This invention also provides the application of the above-mentioned organic-inorganic multi-component hybrid phase change microcapsule energy storage material in the field of phase change energy storage.

[0031] The present invention discloses the following technical effects:

[0032] This invention employs a synergistic design of a multi-component organic phase change core material and an organic-inorganic multi-component hybrid shell material to prepare a phase change energy storage material. The multi-component core material composite overcomes the limitation of a fixed phase change temperature in a single core material, adapting to low-temperature energy storage requirements in various scenarios, ensuring excellent energy storage capacity, and avoiding latent heat decay. The organic-inorganic hybrid shell material combines the film-forming properties of the organic phase with the functionality of the inorganic phase, improving thermal conductivity, mechanical strength, and sealing performance. This resolves the contradictions of low thermal conductivity and weak leakage prevention in pure organic shell materials, and high brittleness and loose core-shell bonding in pure inorganic shell materials.

[0033] This invention uses in-situ polymerization to achieve uniform dispersion of the core material and synergistic coating of the shell material, which can avoid particle agglomeration and core material swelling, and ensure that the microcapsules have uniform morphology and structural integrity.

[0034] The phase change energy storage material of this invention has good stability in cold and hot cycles, reduces core material leakage, maintains energy storage performance, and the raw materials and processes are easy to operate and economical, making it easy to scale up production. It has outstanding application value and promotion prospects in the field of phase change energy storage. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0038] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0039] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0040] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0041] The first aspect of the present invention is to provide an organic-inorganic multi-component hybrid phase change microcapsule energy storage material, comprising a multi-component organic phase change core material and an organic-inorganic multi-component hybrid shell material covering the surface of the multi-component organic phase change core material.

[0042] The multi-component organic phase change core material, by mass, comprises 50-60 parts PEG4000, 20-30 parts PEG6000, 10-20 parts lauric acid, and 1-3 parts Span-80.

[0043] The organic-inorganic multi-component hybrid shell material, by weight, comprises 60-70 parts melamine-formaldehyde prepolymer, 25-35 parts nano-modified particles, 2-5 parts hexamethylenediamine, and 1-3 parts sodium dodecylbenzenesulfonate (SDBS).

[0044] The modified nanoparticles are obtained by mixing nano-SiO2 modified with KH-550 silane coupling agent and nano-Al2O3 modified with KH-570 silane coupling agent at a mass ratio of 15-20:10-15.

[0045] Furthermore, the mass ratio of the multi-component organic phase change core material to the organic-inorganic multi-component hybrid shell material is 6-8:1.

[0046] Furthermore, the preparation method of the melamine-formaldehyde prepolymer includes the following steps:

[0047] Melamine and formaldehyde were mixed in a 35-40% aqueous solution of formaldehyde at a molar ratio of 1:3. Triethanolamine was then added to adjust the pH to 8. The mixture was stirred at 60-65°C until the melamine dissolved, thus obtaining the melamine-formaldehyde prepolymer.

[0048] A second aspect of the present invention provides a method for preparing the above-mentioned organic-inorganic multi-component hybrid phase change microcapsule energy storage material, comprising the following steps:

[0049] (1) Preparation of multi-component organic phase change core material: PEG4000, PEG6000 and lauric acid were melted and stirred at 70-80℃, and Span-80 was added and stirred continuously to obtain core material melt liquid;

[0050] (2) Preparation of modified nanoparticles: Nano-SiO2 was modified with KH-550 silane coupling agent, and obtained by centrifugation, washing and drying. Nano-Al2O3 was modified with KH-570 silane coupling agent, and obtained by centrifugation, washing and drying. The KH-570 silane coupling agent modified nano-Al2O3 was mixed to obtain modified nanoparticles.

[0051] (3) Preparation of organic-inorganic multi-component hybrid shell material predispersant: The melamine-formaldehyde prepolymer, modified nanoparticles, and sodium dodecylbenzenesulfonate were added to water and ultrasonically dispersed and mechanically stirred to obtain organic-inorganic multi-component hybrid shell material predispersant.

[0052] (4) In-situ polymerization method for preparing phase change microcapsules: The core material melt is dropped into the organic-inorganic multi-component hybrid shell material pre-dispersion liquid to form an O / W emulsion. The pH is adjusted to 4.0-4.5, hexamethylenediamine is added, and polymerization is carried out at 85-90℃ for 4-6 hours. After centrifugation, washing and drying, the organic-inorganic multi-component hybrid phase change microcapsule energy storage material is obtained.

[0053] Furthermore, the preparation method of the KH-550 silane coupling agent modified nano-SiO2 includes the following steps:

[0054] In a dispersion medium, nano-SiO2 is modified using KH-550 silane coupling agent at 60-70℃. After separation, washing, and drying, the KH-550 silane coupling agent modified nano-SiO2 is obtained.

[0055] Furthermore, the dispersion medium used to prepare KH-550 silane coupling agent modified nano-SiO2 was an ethanol-water mixture with a mass ratio of 9:1; the modification time was 2-3 hours.

[0056] Furthermore, the mass concentration of nano-SiO2 in the dispersion is 5-8%; the KH-550 is 1-3% of the mass of nano-SiO2.

[0057] Furthermore, the preparation method of the KH-570 silane coupling agent modified nano-Al2O3 includes the following steps:

[0058] In a dispersion medium, nano-Al2O3 was modified using KH-570 silane coupling agent at 70-80℃. After separation, washing, and drying, the KH-570 silane coupling agent-modified Al2O3 was obtained.

[0059] Furthermore, the dispersion medium used in preparing KH-570 silane coupling agent modified nano-Al2O3 was an ethanol-water mixture with a mass ratio of 8:2; the modification time was 2-3 hours.

[0060] Furthermore, the KH-570 is 1-3% of the mass of nano-Al2O3; the mass concentration of nano-Al2O3 in the dispersion is 5-8%.

[0061] This invention employs an in-situ polymerization method, which involves dripping molten core material into a pre-dispersed shell material to form a stable O / W emulsion. Adjusting the pH value to 4.0-4.5 triggers the cross-linking reaction of melamine-formaldehyde prepolymer, which gradually solidifies on the surface of the core material to form a hybrid shell material, achieving precise encapsulation of the core material and the shell material. At the same time, the heat preservation polymerization temperature of 85-90℃ ensures that the cross-linking reaction proceeds fully and avoids thermal decomposition of the core material due to excessive temperature, ultimately forming a phase change microcapsule energy storage material with complete structure and stable performance.

[0062] A third aspect of this invention is to provide the application of the above-mentioned organic-inorganic multi-component hybrid phase change microcapsule energy storage material in the field of phase change energy storage.

[0063] Example 1

[0064] (1) Preparation of multi-component organic phase change core material: Weigh 50 parts of PEG4000, 20 parts of PEG6000 and 10 parts of lauric acid by mass, add the above raw materials to the reaction vessel, heat to 70℃ and start stirring. After the raw materials are completely melted and mixed evenly, add 1 part of Span-80 and continue stirring for 30 minutes to obtain a uniform core material melt. Keep it warm for later use.

[0065] (2) Preparation of modified nanoparticles:

[0066] a. KH-550 modified nano-SiO2: An ethanol-water mixture with a mass ratio of 9:1 was prepared as the dispersion medium. Nano-SiO2 was added to the mixture to achieve a mass concentration of 5%. After uniform dispersion, 1% (by mass) of KH-550 silane coupling agent was added. The mixture was heated to 60℃ and stirred at this temperature for 2 hours. After the reaction was complete, the mixture was centrifuged, the precipitate was collected, washed three times repeatedly with ethanol, and then dried in a 60℃ vacuum drying oven for 4 hours to obtain KH-550 silane coupling agent modified nano-SiO2.

[0067] b. KH-570 modified nano-Al2O3: An ethanol-water mixture with a mass ratio of 8:2 was prepared as the dispersion medium. Nano-Al2O3 was added to the mixture to achieve a mass concentration of 5%. After uniform dispersion, 1% (by mass) of KH-570 silane coupling agent was added. The mixture was heated to 70°C and stirred at this temperature for 2 hours. After the reaction was complete, the precipitate was separated by centrifugation, washed three times with ethanol, and dried in a vacuum drying oven at 60°C for 4 hours to obtain KH-570 silane coupling agent modified nano-Al2O3.

[0068] c. Weigh the KH-550 modified nano-SiO2 and KH-570 modified nano-Al2O3 prepared above at a mass ratio of 15:10, mix them and grind them thoroughly to obtain modified nanoparticles.

[0069] (3) Preparation of organic-inorganic multi-component hybrid shell material predispersant: Weigh 60 parts by mass of melamine-formaldehyde prepolymer (preparation method: melamine and formaldehyde in a 35% formaldehyde aqueous solution at a molar ratio of 1:3, add triethanolamine to adjust the pH to 8, and stir at 60℃ until the melamine is completely dissolved), 25 parts of modified nanoparticles, and 1 part of sodium dodecylbenzenesulfonate (SDBS). Add the above materials to deionized water, first use ultrasonic dispersion treatment for 30 min (ultrasonic power 300W), and then mechanically stir (speed 500r / min) for 1 h to obtain a uniform organic-inorganic multi-component hybrid shell material predispersant.

[0070] (4) In-situ polymerization preparation of phase change microcapsules: The molten core material was slowly dripped into an organic-inorganic multi-component hybrid shell material pre-dispersion (core material to shell material mass ratio 6:1) while stirring (800 r / min) to form a stable O / W emulsion. After the addition was complete, the pH of the emulsion was adjusted to 4.0 with acetic acid, 2 parts of hexamethylenediamine were added, the temperature was raised to 85℃, and polymerization was maintained for 4 h. After the polymerization reaction was completed, heating was stopped, and the system was allowed to cool to room temperature. The microcapsule particles were collected by centrifugation (5000 r / min, 10 min), washed three times alternately with deionized water and ethanol, and finally dried in a vacuum drying oven at 60℃ for 6 h to obtain the organic-inorganic multi-component hybrid phase change microcapsule energy storage material.

[0071] Example 2

[0072] (1) Preparation of multi-component organic phase change core material: Weigh 55 parts of PEG4000, 25 parts of PEG6000 and 15 parts of lauric acid by mass, add the above raw materials into the reaction vessel, heat to 75℃ and start stirring. After the raw materials are completely melted and mixed evenly, add 2 parts of Span-80 and continue stirring for 30 minutes to obtain a uniform core material melt. Keep it warm for later use.

[0073] (2) Preparation of modified nanoparticles:

[0074] a. KH-550 modified nano-SiO2: An ethanol-water mixture with a mass ratio of 9:1 was prepared as the dispersion medium. Nano-SiO2 was added to the mixture to achieve a mass concentration of 6.5% in the dispersion. After uniform dispersion, 2% (by mass) of KH-550 silane coupling agent was added. The mixture was heated to 60℃ and stirred at a constant temperature for 2 hours. After the reaction was completed, the mixture was centrifuged, the precipitate was collected, washed three times with ethanol, and then dried in a vacuum drying oven at 60℃ for 4 hours to obtain KH-550 silane coupling agent modified nano-SiO2.

[0075] b. KH-570 modified nano-Al2O3: An ethanol-water mixture with a mass ratio of 8:2 was prepared as the dispersion medium. Nano-Al2O3 was added to the mixture to achieve a mass concentration of 5%. After uniform dispersion, 1% (by mass) of KH-570 silane coupling agent was added. The mixture was heated to 75°C and stirred at this temperature for 2 hours. After the reaction was complete, the precipitate was separated by centrifugation, washed three times with ethanol, and dried in a vacuum drying oven at 60°C for 4 hours to obtain KH-570 silane coupling agent modified nano-Al2O3.

[0076] c. Weigh the KH-550 modified nano-SiO2 and KH-570 modified nano-Al2O3 prepared above at a mass ratio of 17:12, mix them and grind them thoroughly to obtain modified nanoparticles.

[0077] (3) Preparation of organic-inorganic multi-component hybrid shell material predispersant: Weigh 65 parts by mass of melamine-formaldehyde prepolymer (preparation method: melamine and formaldehyde in a 35% formaldehyde aqueous solution at a molar ratio of 1:3, add triethanolamine to adjust the pH to 8, and stir at 60℃ until the melamine is completely dissolved), 25 parts of modified nanoparticles, and 1 part of sodium dodecylbenzenesulfonate (SDBS). Add the above materials to deionized water, first use ultrasonic dispersion treatment for 30 min (ultrasonic power 300W), and then mechanically stir (speed 500r / min) for 1 h to obtain a uniform organic-inorganic multi-component hybrid shell material predispersant.

[0078] (4) The molten core material was slowly dripped into the organic-inorganic multi-component hybrid shell material pre-dispersion (core material to shell material mass ratio 6:1) while stirring (800 r / min) to form a stable O / W emulsion. After the dripping was complete, the pH of the emulsion was adjusted to 4.0 with acetic acid, 2 parts of hexamethylenediamine were added, the temperature was raised to 85℃, and polymerization was maintained for 4 h. After the polymerization reaction was completed, heating was stopped, and the system was allowed to cool to room temperature. The microcapsule particles were collected by centrifugation (5000 r / min, 10 min), washed three times alternately with deionized water and ethanol, and finally dried in a vacuum drying oven at 60℃ for 6 h to obtain the organic-inorganic multi-component hybrid phase change microcapsule energy storage material.

[0079] Example 3

[0080] (1) Preparation of multi-component organic phase change core material: Weigh 60 parts of PEG4000, 30 parts of PEG6000 and 20 parts of lauric acid by mass, add the above raw materials to the reaction vessel, heat to 75℃ and start stirring. After the raw materials are completely melted and mixed evenly, add 3 parts of Span-80 and continue stirring for 30 minutes to obtain a uniform core material melt. Keep it warm for later use.

[0081] (2) Preparation of modified nanoparticles:

[0082] a. KH-550 modified nano-SiO2: An ethanol-water mixture with a mass ratio of 9:1 was prepared as the dispersion medium. Nano-SiO2 was added to the mixture to achieve a mass concentration of 6%. After uniform dispersion, 2% (by mass) of KH-550 silane coupling agent was added. The mixture was heated to 60℃ and stirred at this temperature for 2 hours. After the reaction was complete, the mixture was centrifuged, the precipitate was collected, washed three times repeatedly with ethanol, and then dried in a 60℃ vacuum drying oven for 4 hours to obtain KH-550 silane coupling agent modified nano-SiO2.

[0083] b. KH-570 modified nano-Al2O3: An ethanol-water mixture with a mass ratio of 8:2 was prepared as the dispersion medium. Nano-Al2O3 was added to the mixture to achieve a mass concentration of 5%. After uniform dispersion, 1% (by mass) of KH-570 silane coupling agent was added. The mixture was heated to 75°C and stirred at this temperature for 2 hours. After the reaction was complete, the precipitate was separated by centrifugation, washed three times with ethanol, and dried in a vacuum drying oven at 60°C for 4 hours to obtain KH-570 silane coupling agent modified nano-Al2O3.

[0084] c. Weigh the KH-550 modified nano-SiO2 and KH-570 modified nano-Al2O3 prepared above at a mass ratio of 17:12, mix them and grind them thoroughly to obtain modified nanoparticles.

[0085] (3) Preparation of organic-inorganic multi-component hybrid shell material predispersant: Weigh 70 parts by mass of melamine-formaldehyde prepolymer (preparation method: melamine and formaldehyde in a 1:3 molar ratio of melamine to formaldehyde, mix melamine with a 35% formaldehyde aqueous solution, add triethanolamine to adjust the pH to 8, and stir at 60℃ until melamine is completely dissolved), 25 parts of modified nanoparticles, and 1 part of sodium dodecylbenzenesulfonate (SDBS). Add the above materials to deionized water, first use ultrasonic dispersion treatment for 30 min (ultrasonic power 300W), and then mechanically stir (speed 500r / min) for 1 h to obtain a uniform organic-inorganic multi-component hybrid shell material predispersant.

[0086] (4) The molten core material was slowly dripped into the organic-inorganic multi-component hybrid shell material pre-dispersion (core material to shell material mass ratio 6:1) while stirring (800 r / min) to form a stable O / W emulsion. After the dripping was complete, the pH of the emulsion was adjusted to 4.0 with acetic acid, 2 parts of hexamethylenediamine were added, the temperature was raised to 85℃, and polymerization was maintained for 4 h. After the polymerization reaction was completed, heating was stopped, and the system was allowed to cool to room temperature. The microcapsule particles were collected by centrifugation (5000 r / min, 10 min), washed three times alternately with deionized water and ethanol, and finally dried in a vacuum drying oven at 60℃ for 6 h to obtain the organic-inorganic multi-component hybrid phase change microcapsule energy storage material.

[0087] Comparative Example 1

[0088] This comparative example uses a blend of a single core material and a pure organic shell material, and the steps are as follows:

[0089] (1) Preparation of single organic phase change core material: Weigh 100 parts of PEG6000 and add it to the reaction vessel. Heat to 75℃ and stir until melted. Add 2 parts of Span-80 and stir for 30 min to obtain core material melt.

[0090] (2) Preparation of pure organic shell material predispersant: Weigh 65 parts of melamine-formaldehyde prepolymer (preparation method is the same as in Example 1) and 2 parts of SDBS, add deionized water, and prepare the predispersant by ultrasonic dispersion and mechanical stirring (parameters are the same as in Example 1).

[0091] (3) In-situ polymerization method for preparing phase change microcapsules: The core material melt was dropped into the pre-dispersion liquid to form an O / W emulsion at a core material to shell material mass ratio of 6:1. The pH was adjusted to 4.3, 3.5 parts of hexamethylenediamine were added, and polymerization was carried out at 87°C for 5 hours. The subsequent treatment was the same as in Example 1 to obtain microcapsule material.

[0092] Comparative Example 2

[0093] This comparative example uses a blend of multiple core materials and a pure inorganic shell material, and the steps are as follows:

[0094] (1) Preparation of multi-component organic phase change core material: Same as in Example 1.

[0095] (2) Preparation of pure inorganic shell material predispersant: Weigh 30 parts of unmodified nano-SiO2 and nano-Al2O3 mixture (mass ratio 15:10) and 2 parts of SDBS, add deionized water, and prepare predispersant by ultrasonic dispersion and mechanical stirring (parameters same as in Example 1).

[0096] (3) Preparation of phase change microcapsules: The core material melt was dropped into the pre-dispersion liquid to form an O / W emulsion at a core material to shell material mass ratio of 6:1. The pH was adjusted to 4.3 and the reaction was carried out at 87°C for 5 hours. The subsequent treatment was the same as in Example 1 to obtain microcapsule materials.

[0097] Comparative Example 3

[0098] This comparative example uses a multi-component core material and an unmodified nanoparticle hybrid shell material for compounding, and the steps are as follows:

[0099] (1) Preparation of multi-component organic phase change core material: Same as in Example 1.

[0100] (2) Preparation of unmodified nanoparticles: Weigh unmodified nano-SiO2 and nano-Al2O3 at a mass ratio of 15:10, mix and grind to obtain unmodified nanoparticles.

[0101] (3) Preparation of hybrid shell material predispersant: Weigh 65 parts of melamine-formaldehyde prepolymer (preparation method is the same as in Example 1), 30 parts of unmodified nanoparticles, and 2 parts of SDBS, add deionized water, and prepare the predispersant by ultrasonic dispersion and mechanical stirring (parameters are the same as in Example 1).

[0102] (4) In-situ polymerization method for preparing phase change microcapsules: Same as in Example 1.

[0103] Effect verification example

[0104] 1. The latent heat of phase change (ΔH) and phase change temperature of the microcapsules were measured using a differential scanning calorimeter (DSC, model TA Q2000) (heating rate 10℃ / min, nitrogen atmosphere).

[0105] 2. Thermal conductivity: The thermal conductivity (λ) of the microcapsule material was tested at 25°C using a hot-wire thermal conductivity meter.

[0106] 3. Mechanical strength: The compressive strength (σ) of the microcapsules was tested using a micro-nano mechanical testing system and the indentation method. The average value was taken after testing 50 particles.

[0107] 4. Leakage prevention performance: Weigh a microcapsule sample with a mass of m1, place it in a petri dish lined with filter paper, and place it in an oven at 80℃ for 24 hours. After cooling, weigh the filter paper and measure the weight gain m2. Leakage rate = (m2 / m1)×100%.

[0108] 5. Thermal cycling stability: The sample was placed in a thermal cycling chamber and subjected to a cycle test of -20℃ (2h) to 80℃ (2h) for a total of 500 cycles. After the cycle, the latent heat of phase change was measured by DSC, and the latent heat retention rate was calculated as (ΔH after the cycle / ΔH before the cycle) × 100%.

[0109] Table 1

[0110]

[0111] The phase change temperatures of embodiments 1-3 of this invention are all in the medium-low temperature range, which can accurately match the temperature requirements of mainstream medium-low temperature energy storage scenarios such as building energy conservation, electronic equipment insulation, and power battery thermal management. The phase change energy storage material of this invention achieves an effective improvement in latent heat of phase change by virtue of the synergistic effect of multiple core materials and the good encapsulation of hybrid shell materials.

[0112] Table 2

[0113]

[0114] The thermal conductivity of Examples 1-3 of this invention is at a high level, far exceeding that of Comparative Example 1 (using a pure organic shell), Comparative Example 2 (using a pure inorganic shell), and Comparative Example 3 (using an unmodified nanoparticle hybrid shell). In terms of compressive strength, the energy storage phase change material of this invention also performs outstandingly, significantly better than each of the comparative examples. This fully demonstrates that the invention achieves a synergistic improvement in thermal conductivity and mechanical strength through the design of the hybrid shell, laying a key foundation for the application of the material in scenarios such as building energy conservation and electronic thermal control, which require both thermal conductivity and structural stability.

[0115] Table 3

[0116] <![CDATA[Initial sample mass m1 (g)]]> <![CDATA[Weight gain of filter paper m2 (g)]]> Leakage rate (%) Example 1 5.000 0.060 1.2 Example 2 5.000 0.045 0.9 Example 3 5.000 0.055 1.1 Comparative Example 1 5.000 0.225 4.5 Comparative Example 2 5.000 0.140 2.8 Comparative Example 3 5.000 0.160 3.2

[0117] The leakage rates of Examples 1-3 of this invention are significantly lower than those of the comparative examples: Compared with Comparative Example 1, which uses a pure organic shell (the pure organic shell has weak anti-swelling ability and is prone to gaps due to core material melting), Comparative Example 2, which uses a pure inorganic shell (the unmodified nanoparticles are loosely bonded, and the shell has microcracks), and Comparative Example 3, which uses an unmodified nanoparticle hybrid shell (particle agglomeration leads to uneven shell structure and reduced sealing performance), the phase change energy storage material of this invention, with its dense structure and good interfacial bonding of the hybrid shell, effectively suppresses core material leakage, providing a key guarantee for maintaining stable energy storage performance during long-term use.

[0118] Table 4

[0119]

[0120] The latent heat retention rates of Examples 1-3 of this invention are much higher than those of the comparative examples: Compared with Comparative Example 1, which uses a pure organic shell (the shell has weak resistance to deformation and is prone to breakage and leakage after cycling), Comparative Example 2, which uses a pure inorganic shell (the core-shell interface is loosely bonded and the core material is easily lost during cycling), and Comparative Example 3, which uses an unmodified nanoparticle hybrid shell (particle agglomeration leads to uneven shell structure and poor cycling stability), the phase change energy storage materials of the present invention, with their stable core material system and strong hybrid shell protection, achieve effective retention of energy storage performance after cycling, providing core support for the reliable application of materials in scenarios requiring long-term and repeated use, such as building energy conservation and electronic thermal control.

[0121] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An organic-inorganic multi-component hybrid phase change microcapsule energy storage material, characterized in that, The organic-inorganic multi-component hybrid shell material is prepared from 60-70 parts of melamine-formaldehyde prepolymer, 25-35 parts of modified nano-particles, 2-5 parts of hexanediamine and 1-3 parts of sodium dodecyl benzene sulfonate. The raw materials of the multi-component organic phase change core material include 50-60 parts of PEG4000, 20-30 parts of PEG6000, 10-20 parts of lauric acid and 1-3 parts of Span-80 by mass fraction. The raw materials of the organic-inorganic multi-component hybrid shell material include 60-70 parts of melamine-formaldehyde prepolymer, 25-35 parts of modified nano-particles, 2-5 parts of hexanediamine and 1-3 parts of sodium dodecyl benzene sulfonate by mass fraction. The modified nano-particles are obtained by mixing KH-550 silane coupling agent modified nano-SiO2 and KH-570 silane coupling agent modified nano-Al2O3 in a mass ratio of 15-20:10-15. 2.The organic-inorganic multi-component hybrid phase change microcapsule energy storage material according to claim 1, characterized in that, The mass ratio of the multi-component organic phase change core material to the organic-inorganic multi-component hybrid shell material is 6-8:

1. 3.The organic-inorganic multi-component hybrid phase change microcapsule energy storage material according to claim 1, characterized in that, The preparation method of the melamine-formaldehyde prepolymer includes the following steps: The melamine-formaldehyde prepolymer is obtained by mixing melamine with formaldehyde aqueous solution with a mass concentration of 35-40% at a melamine to formaldehyde molar ratio of 1:3, then adding triethanolamine to adjust the pH value to 8, and stirring and reacting at 60-65°C until the melamine is dissolved.

4. The method for preparing the organic-inorganic multi-component hybrid phase change microcapsule energy storage material according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Preparation of the multi-component organic phase change core material: melt and stir PEG4000, PEG6000 and lauric acid, then continue to stir after adding Span-80 to obtain a core material melt; (2) Preparation of modified nano-particles: modify nano-SiO2 with KH-550 silane coupling agent, then centrifuge, wash and dry to obtain KH-550 silane coupling agent modified nano-SiO2; modify nano-Al2O3 with KH-570 silane coupling agent, then centrifuge, wash and dry to obtain KH-570 silane coupling agent modified nano-Al2O3; mix the KH-550 silane coupling agent modified nano-SiO2 and the KH-570 silane coupling agent modified nano-Al2O3 to obtain modified nano-particles; (3) Preparation of the organic-inorganic multi-component hybrid shell material pre-dispersion: add the melamine-formaldehyde prepolymer, modified nano-particles and sodium dodecyl benzene sulfonate into water, then ultrasonically disperse and mechanically stir to obtain the organic-inorganic multi-component hybrid shell material pre-dispersion; (4) Preparation of phase change microcapsules by in-situ polymerization: drop the core material melt into the organic-inorganic multi-component hybrid shell material pre-dispersion to form an O / W emulsion, adjust the pH value to 4.0-4.5, add hexanediamine, and polymerize at 85-90°C for 4-6 hours, then centrifuge, wash and dry to obtain the organic-inorganic multi-component hybrid phase change microcapsule energy storage material.

5. The preparation method according to claim 4, characterized in that, The preparation method of the KH-550 silane coupling agent modified nano-SiO2 includes the following steps: In a dispersion medium, modify nano-SiO2 with KH-550 silane coupling agent at 60-70°C, then separate, wash and dry to obtain the KH-550 silane coupling agent modified nano-SiO2.

6. The production method according to claim 5, wherein The dispersing medium is an ethanol-water mixture with a mass ratio of 9:1; the modification time is 2-3 hours.

7. The preparation method according to claim 4, characterized in that, The preparation method of the KH-570 silane coupling agent modified nano-Al2O3 comprises the following steps: In the dispersing medium, the KH-570 silane coupling agent is used to modify the nano-Al2O3 at 70-80 DEG C, and then the KH-570 silane coupling agent modified Al2O3 is obtained through separation, washing and drying.

8. The preparation method according to claim 7, characterized in that, The dispersing medium is an ethanol-water mixture with a mass ratio of 8:2; the modification time is 2-3 hours.

9. The application of the organic-inorganic multi-component hybrid phase change microcapsule energy storage material in the phase change energy storage field according to any one of claims 1-3.

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