CN114539982A - Passive heat management material and preparation method thereof - Google Patents
Passive heat management material and preparation method thereof Download PDFInfo
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- CN114539982A CN114539982A CN202210184572.4A CN202210184572A CN114539982A CN 114539982 A CN114539982 A CN 114539982A CN 202210184572 A CN202210184572 A CN 202210184572A CN 114539982 A CN114539982 A CN 114539982A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
- C09K5/02—Materials undergoing a change of physical state when used
- C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
- C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/90—Passive houses; Double facade technology
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Abstract
The invention belongs to the technical field of new materials, and particularly provides a passive heat management material and a preparation method thereof. The invention utilizes the foaming microspheres with thermal expansion characteristics to form micropores in the phase change energy storage material under the heating condition, thereby preparing the phase change energy storage material with a foaming structure. On one hand, the phase change energy storage material has a cavity structure formed after the microspheres expand, so that the heat conductivity coefficient of the material is greatly reduced, and the material is endowed with good thermal barrier property; on the other hand, phase change energy storage materials absorb a large amount of heat during phase change, thereby reducing the total amount of heat transferred. The two characteristics enable the material to have an excellent passive heat management effect, effectively reduce the fluctuation of the protection target temperature, and show longer working time in the application of heat insulation and heat preservation.
Description
Technical Field
The invention belongs to the technical field of new materials, and particularly relates to a passive heat management material with good heat preservation performance and a preparation method thereof.
Background
With the explosion of green economy and technology, passive thermal management materials play an increasingly important role in thermal management systems. The passive heat management material can maintain the relative stability of the temperature of the protected object on the basis of reducing active energy consumption, and the characteristic enables the protected object to have wide application prospect in the field of heat insulation and heat preservation. For example, a large amount of passive heat management materials are adopted in the design of an outer wall structure of a green energy building passive house emerging at present, so that the active energy consumption of air conditioning, heating and the like can be reduced while the indoor temperature in winter and the temperature in summer is maintained, and the energy sustainable development strategy is promoted.
Among the various manufacturing strategies for passive thermal management materials, the introduction of porous structures is one of the most effective methods. The pores can obviously reduce heat convection and obstruct a heat transfer path, and the existence of the pores enables the material to obtain a structure with low heat conductivity, thereby realizing heat insulation. Over the past several decades, various porous materials with low thermal conductivity have been developed and applied in various fields such as food storage and transportation, indoor thermal comfort maintenance, and protection of human bodies and electronic devices in harsh environments. However, for porous materials that rely solely on low TC structures to isolate heat, their ability to stabilize temperature is ultimately limited because heat is still constantly being transferred as long as there is a temperature difference. In recent years, Phase Change Materials (PCMs) have received a great deal of attention in the field of passive thermal management because PCMs can absorb or release latent heat during phase change to reduce the total heat transferred, thereby maintaining a relatively constant temperature. In the lithium battery thermal management, the PCMs can be used for absorbing heat generated in the high-power operation of the battery so as to maintain the relative stability of the temperature, protect the battery assembly and realize the maintenance of the normal operation of the battery by taking the measure of non-active temperature reduction. It is expected that if the ability of PCMs to absorb and release latent heat is combined with the insulating ability of porous materials, synergistic passive thermal management properties are expected to be achieved, thereby more efficiently and longer lasting exerting the ability of the passive thermal management material to stabilize temperature.
At present, methods for combining a phase change material and a porous material include pouring the phase change material into the porous material, macroscopically superposing the two materials, directly foaming the phase change material, and the like. However, these methods may suffer from problems such as clogging of the pores of the porous material or leakage of the phase change material, difficulty in stabilizing the temperature for a long time, and effective exertion of good passive thermal management properties of the material. Based on the great advantages of the passive heat management material in reducing energy consumption and the wide application prospect in the field of heat insulation and heat preservation, the development of the passive heat management material with good temperature stability has great significance.
Disclosure of Invention
The invention aims to provide a passive heat management material with good heat preservation performance, a preparation method thereof and application thereof in the field of passive heat management so as to improve the working efficiency and application performance of the passive heat management material.
The passive heat management material provided by the invention can release or absorb latent heat in the phase change process of the material, so that the temperature is kept stable in a certain range, and the passive heat management material has a good heat conduction blocking effect with a material with a low heat conductivity coefficient.
The function of phase change latent heat absorption or release is realized by selecting a substance with higher phase change enthalpy and proper phase change temperature, and the low heat conductivity coefficient is realized by introducing a pore structure.
Solid-liquid phase change materials typically have a high enthalpy of phase change, with the phase change temperature being related to their composition or structure. However, when the solid-liquid phase-change material is heated to be changed into a liquid state, i.e., a melt, the melt viscosity is low, the strength is low, and pores cannot be introduced.
The invention successfully prepares the phase change energy storage material with a foaming structure by utilizing the foaming microspheres with thermal expansion characteristics to form micropores in the phase change energy storage material under the heating condition.
Based on the analysis of the material characteristics, the preparation method of the passive heat management material provided by the invention utilizes the foaming microspheres with the thermal expansion characteristic to form micropores in the phase change energy storage material under the heating condition, so as to prepare the phase change energy storage material with a foaming structure.
The phase change energy storage material is mainly a solid-liquid phase change material, that is, a substance which can generate solid-liquid (heating process) or liquid-solid (cooling process) transformation at a specific temperature and can absorb or release latent heat of phase change.
Specifically, the solid-liquid phase change material is mainly various organic solid-liquid materials, including various paraffins, aliphatic hydrocarbons, fatty acids and derivatives thereof, polyethylene glycol and the like. And may be one or more of the above phase change materials. The different corresponding materials are mainly reflected in the difference of phase-change temperature and phase-change enthalpy.
The foaming microspheres with thermal expansion characteristics refer to various thermal expansion microspheres with the volume capable of expanding when being heated, and generally comprise a polymer shell and periodical substances sealed in the polymer shell; the outer shell softens and the material within the shell expands when heated, thereby causing a significant increase in expanded microsphere volume; the outer shell of the expansion microballoons becomes hard again and the volume is fixed when the outer shell is cooled; the higher the temperature, the higher the expansion ratio, within a temperature lower than the temperature at which the expanded microspheres are broken.
The preparation method can be solution compounding or melt compounding. Solution compounding, namely dispersing a phase change energy storage material in a solution, adding thermal expansion microspheres, uniformly mixing, removing a solvent, preparing into a specific shape or size, and heating to a specific temperature to expand the microspheres; the melting compounding is that the phase change material is melted, the expansion microsphere is added into the melt at a lower temperature and mixed evenly, and the mixture is heated to a specific temperature after being made into a specific shape or size, so that the microsphere is expanded.
The method for expanding the heat-expandable microspheres by heating can be one-time heating expansion or multiple times of heating to gradually expand the microspheres. The higher the foaming temperature, the larger the foaming ratio.
In the preparation method, the phase change energy storage material and the foaming microspheres are prepared from the following components in parts by mass:
phase change energy storage material: 100 parts of (a) a water-soluble polymer,
foaming microspheres: 1-100 parts;
the more the addition amount of the foaming microspheres is, the larger the foaming magnification is under the same foaming conditions.
The passive heat management material prepared by the invention is essentially a phase change energy storage material with a foaming structure. The microspheres form a cavity structure after expansion, so that the heat conductivity coefficient of the material is greatly reduced, and the material is endowed with good thermal barrier property; phase change energy storage materials absorb a large amount of heat during phase change, thereby reducing the total heat transferred. The two characteristics enable the material to have an excellent passive heat management effect, relatively stable target temperature can be kept for a longer time, and the material is widely applied to the fields of heat insulation and preservation and the like.
The invention has the following technical characteristics and functional advantages
(1) The raw materials used in the invention are common chemical products, are cheap and easily available, and are non-toxic and harmless; the preparation method of the porous phase-change foam plate provided by the invention is green and environment-friendly, is simple and easy to obtain, and is easy to realize large-scale production;
(2) the passive heat management material provided by the invention has low heat conductivity coefficient and certain phase change latent heat, can simultaneously play the heat blocking role of the porous material and the storage or release role of the phase change material on heat energy, and realizes the effect of stabilizing the temperature of an object for a longer time;
(3) the passive heat management material provided by the invention can store heat energy through low heat conduction structure heat insulation and phase change materials, and has the capability of stabilizing the temperature for a long time in heat insulation application;
(4) the passive heat management material provided by the invention can store heat energy through the phase-change material, and slowly release the heat energy through the low heat conduction structure to be used as a thermal therapy dressing, so that a more lasting hot compress effect is realized;
(5) the passive heat management material provided by the invention can effectively prevent a heat target from transferring temperature to the outside through the heat insulation of the porous structure and the heat storage and release effect of paraffin, so that the stealth of a high-temperature object under an infrared camera is realized; similarly, the porous phase-change foam also has an infrared shielding effect on low-temperature objects in the environment;
(6) the passive heat management material provided by the invention can be used as an outer wall material of a building, and can block heat exchange between the internal temperature of the building and the external environment through the heat insulation of a porous structure and the heat storage and release effect of paraffin, so that the fluctuation of the indoor temperature in the severe and variable external environment is relieved, and the load of an air conditioner and heating is reduced.
Detailed Description
The present invention is further described in detail below by way of specific examples, but the scope of protection is not limited to the examples described below, which are exemplary and not limiting.
Example 1
200 g of paraffin wax (melting point: 40 ℃) was added to a beaker, and after heating to 60 ℃ to completely melt the paraffin wax, 30g of thermally expandable microspheres (model 180DU45, manufactured by PolyChem Alloy, USA) were added thereto, and after stirring, the mixture was cooled to room temperature to obtain a mixture. 20 g of the mixture was taken and pressed into a 1 mm sheet by a press. And then placing the thin sheet between the upper plate and the lower plate of a molding press with the temperature of 180 ℃ and the distance of 2mm, heating and foaming for 2min, taking out the thin sheet, placing the thin sheet between cooling plates of the molding press, adjusting the distance between the upper plate and the lower plate to be 2mm, and cooling to obtain the passive heat management material with the thickness of 2mm, smooth surface and a foaming structure.
The foamed sheet and a control (unfoamed material, 2 mm) were placed on a hot plate at 50 ℃ and the surface temperature was recorded. For the unfoamed sample, the time taken for its upper surface temperature to rise to 50 ℃ was about 1000 s; and the temperature of the upper surface of the foaming sample is raised to 39 ℃, and the time required for raising the temperature of the upper surface of the foaming sample to be more than 3000s is long, so that the foaming sample shows good heat insulation performance.
Example 2
Otherwise, as in example 1, 200 g of paraffin wax (melting point: 40 ℃) was added to a beaker, heated to 60 ℃ to be completely melted, and 80g of thermally expandable microspheres were added to prepare a passive thermal management sheet having a thickness of 2mm and a foamed structure.
The prepared foamed sheet is used for simulating the building heat preservation process: the plates are bonded into a cubic box with the side length of 5cm, and the external wall of a building is simulated. A small piece of ice was placed in the box on a 30 ℃ hot plate. When the ice in the box is found to be completely melted, 2000-2200s of time is needed. If ice cubes of similar size are placed directly on the hot plate, only 120 and 130 seconds are required for complete melting.
Example 3
Otherwise, as in example 2, the mixture was pressed into 2mm sheets by a molding press, placed in a heating box at 180 ℃ and foamed for 5min, and then taken out, and immediately pressed into passive thermal management sheets having a thickness of about 5mm and a foamed structure by a normal temperature molding press.
When the thermal insulation effect of the building was simulated similarly to example 2, it was found that it took more than 3000 seconds for the foamed sheet having a thickness of 5mm to completely melt the ice cubes placed in the box.
Example 4
Otherwise as in example 2, the paraffin wax used was replaced with stearic acid.
The prepared passive heat management sheet with the same thickness of 2mm and a foaming structure is used for simulating the time of 1600-1700s required by the complete melting of ice blocks in the box in the building heat preservation process.
Example 5
In the same manner as in example 1, 20 g of the obtained mixture was pressed into a sheet of 0.5mm by a molding press, and then a similar foaming process was performed to prepare a passive heat management material having a thickness of 2mm, a smooth surface and a foamed structure.
The resulting foamed sheet was placed on a 50 ℃ hot plate and the upper surface temperature was recorded. For the unfoamed sample, the time taken for its upper surface temperature to rise to 50 ℃ was about 1000 s; and the temperature of the upper surface of the foamed sample was raised to a temperature of 39 c for a time exceeding 3500 s.
Example 6
300 g of paraffin (melting point 52 ℃) and 53g of thermally expandable microspheres are added into a beaker filled with 500mL of cyclohexane solvent, heated to 80 ℃ to dissolve the paraffin and uniformly mix with the thermally expandable microspheres, cooled to room temperature, and the solvent is dried to obtain a mixture. 500 g of the mixture from which the solvent was removed was taken out and pressed into a 0.8mm thin sheet by a die press. And then placing the thin sheet between plates of a molding press with the temperature of 175 ℃ and the distance of 2mm between the upper plate and the lower plate for heating and foaming for 5min, taking out the thin sheet and placing the thin sheet into a normal-temperature molding press, and adjusting the distance between the upper plate and the lower plate to be 2mm to obtain the passive heat management material with the thickness of 2mm, smooth surface and a foaming structure.
The prepared foamed phase-change plate and a reference sample (unfoamed material, 2 mm) were heated to 80 ℃, and then adhered to the surface of a cotton material, and the temperature between the plate and the cotton was recorded. For the unfoamed sample, the temperature drop from 52 ℃ to 40 ℃ maintained 1220s in total, while for the same foamed sample, 2160s was maintained.
Example 7
The same procedure as in example 5 was repeated except that 300 g of paraffin wax (melting point: 52 ℃ C.) and 30g of thermally expandable microspheres were used. And heating the prepared foaming phase-change plate to 80 ℃, then adhering the foaming phase-change plate to the surface of an object made of cotton cloth, and recording the temperature between the plate and the cotton cloth. It was found that a decrease from 52 ℃ to 40 ℃ maintained all 1820 s.
Example 8
In the same manner as in example 5, 500 g of the mixture from which the solvent was removed was pressed into a 0.8mm sheet by a press machine. Then, the sheet was foamed in a mold press at 175 ℃ and a distance of 2mm for 2min, and then placed in a heating chamber at 185 ℃ for further foaming for 15 min. And (3) taking out the materials, putting the materials into a normal-temperature molding press, and adjusting the distance between an upper plate and a lower plate to be 3mm to obtain the passive heat management material with the thickness of 3mm, smooth surface and a foaming structure.
The same evaluation as in example 5 was carried out on the obtained foamed phase change sheet, and it was found that the temperature was decreased from 52 ℃ to 40 ℃ for 2900 s in total.
Claims (6)
1. A preparation method of a passive heat management material is characterized in that foaming microspheres with thermal expansion characteristics are utilized to form micropores in a phase change energy storage material under the heating condition, so that the phase change energy storage material with a foaming structure is prepared;
the phase change energy storage material is a solid-liquid phase change material, namely, the phase change energy storage material can generate phase change at a specific temperature: the phase transition from solid to liquid occurs in the heating process, the phase transition from liquid to solid occurs in the cooling process, and substances capable of absorbing or releasing phase change latent heat can be absorbed;
the foaming microspheres with thermal expansion characteristics refer to various thermal expansion microspheres with the volume capable of expanding when being heated, and specifically comprise a polymer shell and articles sealed in the polymer shell; the outer shell softens and the material within the shell expands when heated, thereby causing a significant increase in expanded microsphere volume; the outer shell of the expanded microspheres stiffens again and becomes fixed in volume when cooled; the higher the temperature, the higher the expansion ratio, within a temperature lower than the temperature at which the expanded microspheres are broken.
2. The method according to claim 1, wherein the solid-liquid phase change energy storage material is an organic solid-liquid material, and is specifically selected from paraffin, aliphatic hydrocarbons, fatty acids or derivatives thereof, and polyethylene glycol.
3. The preparation method according to claim 1, wherein the foaming microspheres with thermal expansion characteristics are used for forming micropores in the phase change energy storage material under the condition of heating, and a solution compounding or melting compounding technology is adopted; the solution compounding comprises the steps of dispersing a phase change energy storage material into a solution, adding thermal expansion microspheres, uniformly mixing, removing a solvent, preparing into a specific shape or size, and heating to a specific temperature to expand the microspheres; the melting compounding is that the phase change material is melted, the expanded microsphere is added into the melt at lower temperature and mixed evenly, and the mixture is heated to specific temperature after being made into specific shape or size, so that the microsphere is expanded.
4. The method according to claim 3, wherein the heat expansion of the thermally expandable microspheres is carried out by one heat expansion or by a plurality of heat expansions of the microspheres.
5. The preparation method according to any one of claims 1 to 4, wherein the phase change energy storage material and the foamed microspheres are prepared from the following components in parts by mass:
phase change energy storage material: 100 parts of (a) a water-soluble polymer,
foaming microspheres: 1-100 parts.
6. A passive heat management material obtained by the preparation method of any one of claims 1 to 45, which is a phase change energy storage material with a foaming structure; the microspheres form a cavity structure after expansion, so that the heat conductivity coefficient of the material is greatly reduced, and the material is endowed with good thermal barrier property; phase change energy storage materials absorb a large amount of heat during phase change, thereby reducing the total heat transferred.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5665785A (en) * | 1993-09-24 | 1997-09-09 | Urethane Technologies, Inc. | Process for forming microcellular structures having an integral skin and products thereof |
| CN107383662A (en) * | 2017-09-01 | 2017-11-24 | 重庆卡美伦科技有限公司合川分公司 | A kind of energy-saving heat preserving polrvinyl benzene composite board material and preparation method thereof |
| CN112424309A (en) * | 2018-07-20 | 2021-02-26 | 松本油脂制药株式会社 | Thermally expandable microspheres and use thereof |
| CN113061284A (en) * | 2021-03-24 | 2021-07-02 | 中国科学院深圳先进技术研究院 | Light organic composite material and preparation method thereof |
-
2022
- 2022-02-28 CN CN202210184572.4A patent/CN114539982A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5665785A (en) * | 1993-09-24 | 1997-09-09 | Urethane Technologies, Inc. | Process for forming microcellular structures having an integral skin and products thereof |
| CN107383662A (en) * | 2017-09-01 | 2017-11-24 | 重庆卡美伦科技有限公司合川分公司 | A kind of energy-saving heat preserving polrvinyl benzene composite board material and preparation method thereof |
| CN112424309A (en) * | 2018-07-20 | 2021-02-26 | 松本油脂制药株式会社 | Thermally expandable microspheres and use thereof |
| CN113061284A (en) * | 2021-03-24 | 2021-07-02 | 中国科学院深圳先进技术研究院 | Light organic composite material and preparation method thereof |
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