CN113862815A - Passive radiation refrigerating material and product thereof - Google Patents

Passive radiation refrigerating material and product thereof Download PDF

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CN113862815A
CN113862815A CN202010617668.6A CN202010617668A CN113862815A CN 113862815 A CN113862815 A CN 113862815A CN 202010617668 A CN202010617668 A CN 202010617668A CN 113862815 A CN113862815 A CN 113862815A
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modified graphene
passive
set forth
graphene
particles
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王克
杨扬
陈桥
川崎学
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Toray Advanced Materials Research Laboratories China Co Ltd
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
    • D01F6/48—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polymers of halogenated hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/004—Reflecting paints; Signal paints
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00—General methods for the manufacture of artificial filaments or the like
    • D01F1/02—Addition of substances to the spinning solution or to the melt
    • D01F1/10—Other agents for modifying properties
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F1/00—General methods for the manufacture of artificial filaments or the like
    • D01F1/02—Addition of substances to the spinning solution or to the melt
    • D01F1/10—Other agents for modifying properties
    • D01F1/106—Radiation shielding agents, e.g. absorbing, reflecting agents
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

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  • General Chemical & Material Sciences (AREA)
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Abstract

The invention provides a passive radiation refrigeration material, wherein fluorine-containing resin capable of directly radiating heat to the space is selected as a base material, modified graphene which is specially processed and has extremely high thermal conductivity and reflectivity is introduced into the base material, and the modified graphene are fully mixed to prepare a porous structure material capable of efficiently reflecting sunlight. All parts coordinate with each other to exert their own characteristics, and finally, an ultra-high reflection effect on sunlight and a heat scattering effect are obtained. The highest reflection efficiency of visible light and infrared light is more than 98%, and the infrared emissivity of the infrared light in an atmospheric window wave band is more than 99%. The invention can bring obvious cooling effect to the object covered by the device through the characteristics of the device under the condition of no external energy.

Description

Passive radiation refrigerating material and product thereof
Technical Field
The invention belongs to the field of energy-saving materials, and particularly relates to an efficient passive radiation refrigeration material energy-saving material containing modified graphene, high-reflectivity particles and fluorine-containing resin and a product thereof.
Background
The modern society economy develops rapidly, and the living standard of people is improved day by day. But simultaneously brings about a lot of problems, and the environmental energy problems such as urban population increase, energy consumption aggravation, greenhouse effect, environmental deterioration and the like bring hidden troubles to all countries around the world. The greenhouse effect is a heat preservation effect formed by lack of heat exchange between a closed space transmitting sunlight and the outside, namely short-wave solar radiation can penetrate through the atmosphere and enter the ground, and long-short radiation emitted after the ground is warmed is absorbed by substances such as carbon dioxide in the atmosphere, so that the effect of warming the atmosphere is generated. In hot summer, the temperature of a building irradiated by sunlight for a long time is much higher than the temperature of the surrounding air, and meanwhile, due to the fact that urban building groups are crowded, airflow is not easy to circulate, heat accumulation cannot be dissipated, and a heat island effect is formed. To alleviate this high temperature, one would increase the air conditioning energy consumption by 5% -8% by consuming other energy sources, such as an average ambient temperature rise of 1 ℃. The increase in power demand for coal-fired power plants means that more greenhouse gas emissions are generated during power generation, causing global temperature rises, resulting in a vicious circle. Under the circumstances, the urgent demand of high-performance passive radiation refrigeration material energy-saving materials is increasing.
The passive radiation refrigeration material is a material which can realize passive cooling and achieve the purpose of saving energy by transmitting the heat of an object to the low-temperature universe in an electromagnetic wave mode through an infrared window of the atmosphere. Different from the common active cooling mode in life (such as air conditioning refrigeration), the passive cooling material does not need to consume a large amount of electric energy and other extra energy, so that the passive radiation cooling material can relieve the global warming problem in a very energy-saving mode.
Since the discovery of graphene in 2004 by the laboratory micromechanical exfoliation method by both concutant norwochoff and anderley glom at manchester university, uk, its excellent mechanical, electrical and thermal properties have received attention from material scientists. Graphene is the thinnest nano material so far, has excellent mechanical properties (tensile strength of 130GPa and Young modulus of up to 1TPa) and outstanding conductivity (conductivity of 10 S.m)-1) The radius-thickness ratio has the highest thermal performance (thermal conductivity coefficient 5300W/mK) in the known materials. If can let graphite alkene can play a role in passive radiation refrigeration material, can greatly promote the refrigeration cooling efficiency of material.
Patent document 1 discloses a radiation refrigeration film with adjustable cooling effect, which is a three-layer composite film, wherein the uppermost layer is a temperature-sensitive color-changing layer; the middle layer is a radiation refrigeration layer and consists of a radiation refrigeration transparent polymer substrate and micron-sized spheres distributed in the radiation refrigeration transparent polymer substrate; the lowest layer is a metal coating reflection heat insulation layer. The effect of cooling can be realized through compounding three layers of films. However, in the method, the three layers of films made of different materials are compounded, so that the refrigerating efficiency of the composite film is not ideal due to the change of the refractive index of light at the interface and the effect of the material, and meanwhile, the preparation process of the three-layer composite film is very complicated.
In patent document 2, a graphene oxide modified energy-saving coating is provided, which performs targeted modification treatment on a radiation filler, so that compatibility among raw materials is better, and meanwhile, the added graphene oxide material can increase the heat conduction speed of the radiation filler, improve the heat emission efficiency of the radiation filler, and significantly improve the cooling and heat insulation effects and mechanical properties of the energy-saving coating. However, graphene oxide for increasing the heat conduction speed of the coating is treated by an intercalator and a strong oxidant, the heat conduction performance is seriously damaged, and the graphene oxide is far from the theoretical heat conduction coefficient of graphene, so that the graphene oxide hardly has an excellent heat conduction effect.
Documents of the prior art
Patent document
Patent document 1: CN 108656682A
Patent document 2: CN 109233520A
Disclosure of Invention
In order to solve the above problems and obtain an energy-saving and efficient passive radiation refrigeration material, after intensive research, the inventors of the present invention found that radiation and reflection capabilities of a material can be greatly improved by forming a special porous material structure with a resin having a specific wavelength capable of radiating, graphene having high thermal conductivity, and particles having high reflectivity, thereby obtaining an energy-saving and efficient passive radiation refrigeration material. Specifically, the present invention provides a passive radiation refrigeration material, which comprises modified graphene, high-reflectance particles, and a fluorine-containing resin, and has a porous structure having the modified graphene and the fluorine-containing resin as a skeleton, wherein the high-reflectance particles are grafted to a layer of the modified graphene.
The present invention will be specifically described below.
< fluorine-containing resin >
In the passive radiation refrigeration material, fluorine-containing resin is used as a base material. Specifically, the fluororesin used as the base material in the material may be at least one of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, an ethylene-tetrafluoroethylene copolymer, an ethylene-chlorotrifluoroethylene copolymer, polyvinyl fluoride, and polyvinylidene fluoride-co-hexafluoropropylene. From the viewpoint of availability of the resin and solubility in a solvent, polyvinylidene fluoride (PVDF) or polyvinylidene fluoride-co-hexafluoropropylene (P (VdF-HFP)) is preferable.
The working principle of radiation refrigeration is to release the heat of a closed area to a low-temperature space in the form of heat radiation by covering the area with an infrared radiation material having an enhancing effect. The earth's atmosphere being composed of N2、O2、CO2And the mixture of various gases including water vapor and the like can absorb, scatter and emit electromagnetic waves, and under the condition of clear sky (without cloud/fog blocking), the earth atmosphere has a transparent radiation window, and the wavelength range of the window covers 8-13 mu m. Electromagnetic waves in this wavelength range can penetrate directly into the atmosphere to reach space, and only a small portion is absorbed. In order to allow the energy of the refrigeration area to be transferred through the window and released into the universe, it is necessary to ensure that the radiation spectrum of the refrigeration material lies predominantly in this atmospheric window. The fluorine-containing resin is selected as the base material of the present invention because the polymer containing fluorine bonds emits heat radiation substantially within the wavelength of the radiation window, and the heat of the object can be directly radiated to the universe through the atmosphere. And the heat radiation emitted by other materials is not in the wavelength of the radiation window and cannot penetrate the atmosphere, so that the aim of relieving the global greenhouse effect cannot be fulfilled.
< modified graphene >
The passive radiation refrigeration material contains modified graphene and has a porous structure with the modified graphene and fluorine-containing resin as frameworks. According to the invention, the material has a strong reflection effect on infrared rays by virtue of the porous structure.
The modified graphene used in the invention can be obtained by performing surface treatment on graphene obtained by a chemical stripping method. Commonly used graphene is largely classified into 3 types: CVD method graphene, physical exfoliation method graphene, chemical exfoliation method graphene. The CVD graphene can be a single layer, has few defects and excellent thermal conductivity, but has no functional groups on the surface, is difficult to perform surface treatment, has poor dispersibility and high price, and is not suitable for large-scale application. The physical stripping method is simple and convenient in graphene preparation method, but the thickness is difficult to thin, and the property is close to that of natural graphite. The chemically stripped graphene has a functional group on the surface, can be subjected to surface treatment as required and can also be very thin, and the defects can be greatly repaired by means of high-temperature reduction, so that the graphene prepared by a chemical stripping method is selected.
In the invention, the content of the modified graphene accounts for 0.1-0.5 wt% of the modification of the passive radiation refrigeration material. By making the content of the modified graphene above 0.1 wt%, the modified graphene can form a complete and continuous heat dissipation path in the material. By setting the content of the modified graphene to 0.5 wt% or less, the modified graphene can be prevented from agglomerating, the modified graphene can be well dispersed in the material, and the moldability and the material performance of the material can be improved. Further, the content of the modified graphene is preferably 0.2 wt% or more and 0.45 wt% or less of the passive radiation refrigeration material, and within this range, the modified graphene is most uniformly dispersed, and the effect of heat conduction in the material can be optimally exerted.
The sheet diameter of the modified graphene used in the present invention, which is D50, is not particularly limited as long as the effects of the present invention are not impaired, and is preferably 2 to 50 μm. The modified graphene with the sheet diameter size in the range is easier to lap joint into a heat conduction channel, and is not easy to agglomerate. The modified graphene platelet size D50 can be measured by the volume-based mode of particle size distribution testing, but is not limited to this test method.
The modified graphene used in the present invention has a thickness within a range not to impair the effects of the present inventionThe particle size is not particularly limited, but is preferably 0.4 to 12 nm. By making the thickness within this range, the modified graphene can sufficiently exhibit its high thermal conductivity. The thickness of the modified graphene may be measured by an Atomic Force Microscope (AFM), but is not limited to this test method. Using J scanner Si3N4The needle is scanned in contact mode at a frequency of 1.0-2.4 Hz. The modified graphene test pretreatment method comprises the following steps: the modified graphene was dispersed in N-methylpyrrolidone (NMP) as a solvent to prepare a 0.002 wt% dispersion, which was dropped on a mica sheet, dried, and subjected to AFM measurement.
In addition, the thickness of one layer of modified graphene is about 0.4nm, and thinner graphene is better in thermal conductivity, so that the thickness of the modified graphene is more preferably 0.4 to 4 nm.
The thickness of the graphite oxide is finely adjusted by controlling the addition amount of an oxidant in the oxidation process; the sheet diameter size of the graphite oxide is adjusted by micronization treatment in the later stage of the reaction, wherein the micronization treatment refers to ultrasonic treatment and various treatment means with micronization treatment function.
The modified graphene used in the present invention is obtained by modifying with a surface treatment agent, which may be selected from silane coupling agents containing amino groups, and KH-550 may be used in view of the effect and ease of availability.
In the present invention, the method of preparing the modified graphene may be as follows, but is not limited thereto. High-reflectivity particles are grafted on the surface of graphene through a hydrothermal reaction. And treating the product by using a surface treating agent to obtain the modified graphene. The growth of high-reflectivity particles on the modified graphene sheets can be characterized by Scanning Electron Microscopy (SEM), but is not limited to this test method.
< particles having high reflectance >
The modified graphene in the passive radiation refrigeration material is modified by a surface treatment agent, and simultaneously, high-reflectivity particles are grafted on a sheet layer. Here, the high-reflectivity particles grafted on the sheet layer means that the high-reflectivity particles are not simply adsorbed on the surface of the graphene but are grown on the surface through a chemical reaction, that is, the high-reflectivity particles are tightly bonded to the graphene. Therefore, the high-reflectivity particles can not fall off due to external factors in the material forming process, so that the particles can fully play the expected function in the material.
In the passive radiation refrigeration material, the high-reflectivity particles are particles with high reflectivity to sunlight, and the reflectivity to infrared rays can reach more than 85%. The high-reflectance particles include, specifically, one or more of silver, gold, copper, aluminum, and silicon dioxide. Among them, silver is preferable because the reflectance against infrared light can be 99% or more. The reflectivity of the particles can be measured by a reflectometer, but is not limited to this test method.
In the invention, the content of the high-reflectivity particles accounts for 0.05-0.3 wt% of the passive radiation refrigeration material. By setting the content of the high-reflectance particles to 0.05 wt% or more, the effect of the high-reflectance particles on reflecting sunlight can be sufficiently exhibited. The content of the high-reflectivity particles is less than 0.3 wt%, so that the preparation formability of the passive radiation refrigeration material can be improved, and the overall performance of the material can be improved. Further, the content of the high-reflectance particles is preferably 0.1 wt% or more and 0.25 wt% or less of the passive radiation refrigeration material, and within this range, the high-reflectance particles can be made to fully function in the passive radiation refrigeration material without affecting the molding of the material. The content of the high-reflectance particles may be controlled by the concentration of the reaction solution of the hydrothermal reaction.
In the present invention, the diameter of the high-reflectance particles grafted on the graphene sheet layer is not particularly limited as long as the effect of the present invention is not impaired, but it is preferable that D10 be 0.1 μm, D50 be 0.5 μm, and D90 be 1 μm. The high-reflectivity particles with the diameter in the range can be maximum, and the reflection effect on infrared light is best. The diameter size of the high-reflectivity particles grafted onto the graphene sheet layer can be adjusted by the reaction temperature and the reaction time. The diameter of the high-reflectivity particles can be measured by microscopy, but is not limited to this test method. Microscopy: the particle size of the particles was measured by preparing 0.002 wt% dispersion of the graphene grafted with particles, dropping the dispersion on a glass slide, drying, measuring with SEM (scanning electron microscope), and directly observing and measuring the planar projection image of the particles by an imaging method.
< porogen >
In the present invention, a porogen may be contained in addition to the fluorine-containing resin, the modified graphene, and the high-reflectance particles. The pore-forming agent can be one or more of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) with different molecular weights.
< other auxiliary Agents >
The passive radiation refrigeration material of the invention can also contain other auxiliary agents for adjusting the aperture. The other auxiliary agents include sodium borohydride, lithium borohydride, ammonium chloride, lithium chloride, sodium chloride, and the like, and these auxiliary agents may be used alone or in combination of 2 or more.
< Passive radiation refrigeration Material >
In the invention, the porosity of the material is 60-80%, the pore diameter range of the material is 0.1-1 μm, the mode pore diameter of the material is 200-400nm, and the mode pore diameter refers to the pore with the highest proportion in the pore diameter distribution.
The high porosity of the material is advantageous for reflecting more sunlight, but too high porosity is disadvantageous for the shaping of the material, and thus the porosity of the material is limited to the range of 60 to 80%, preferably 70 to 80%.
The material has an aperture in the range of 0.1-1 μm and is capable of reflecting infrared light more efficiently. For the same reason, the maximum aperture of the material is within the range of 200-400nm, which can reflect infrared light more effectively, and the preferred maximum aperture is 300-350nm, which has the strongest effect of reflecting infrared light.
The pore size and porosity of the material can be adjusted by adjusting the concentration of different additives and the concentration of resin in the preparation process of the material. The porosity, the pore size range and the most probable pore size of the passive radiation refrigeration material can be measured by a nitrogen adsorption instrument, but the method is not limited to the test method.
In the invention, the method for preparing the passive radiation refrigeration material can be a solvent dissolution method and a melting method (a melt spinning stretching method or a thermally induced phase separation method). As the preparation method of the modified graphene-containing passive radiation refrigeration material, a solvent dissolution method is preferred. The reason is that the modified graphene is easier to disperse in a solvent than in a molten resin and has very good compatibility with a fluorine-containing resin of a material matrix, so that the preparation method is more favorable for dispersing the modified graphene in a passive radiation refrigeration material, and the agglomeration phenomenon possibly occurring in the fluorine-containing resin matrix during the preparation by a melting method is not easy to occur.
ADVANTAGEOUS EFFECTS OF INVENTION
The invention overcomes the problems of complicated preparation process and low refrigeration efficiency of the existing refrigeration material. The method comprises the steps of grafting high-reflectivity particles on the surface of modified graphene to obtain a graphene material with high thermal conductivity and high reflectivity, carrying out high-temperature heat treatment on the graphene grafted with the high-reflectivity particles to ensure that the high-thermal-conductivity graphene material with few surface defects can be obtained, and finally carrying out surface treatment on the obtained graphene material to solve the problem that the graphene is easy to agglomerate due to high specific surface, so that the graphene material has good dispersibility in a base material, and the heat conduction and reflection effects of the graphene material can be fully exerted. The fluorine-containing resin selected for the substrate of the present invention can radiate the heat of the covered area to the universe in the form of heat radiation. The modified graphene is compounded with the fluorine-containing resin, and a porous structure material is prepared by adopting a special preparation process, wherein gaps in the porous material scatter and reflect sunlight due to the difference of refractive indexes of the gaps and surrounding polymers. Effectively dissipating heat to the universe with inherent emissivity while avoiding solar heating.
The invention provides a passive radiation refrigeration material, wherein fluorine-containing resin capable of directly radiating heat to the space is selected as a base material, modified graphene which is specially processed and has extremely high thermal conductivity and reflectivity is introduced into the base material, and the modified graphene are fully mixed to prepare a porous structure material capable of efficiently reflecting sunlight. All parts coordinate with each other to exert their own characteristics, and finally, an ultra-high reflection effect on sunlight and a heat scattering effect are obtained. The highest reflection efficiency of visible light and infrared light is more than 98%, and the infrared emissivity of the infrared light in an atmospheric window wave band is more than 99%. According to the invention, the high-performance energy-saving cooling material can be obtained by a simple-step and high-efficiency method, and the application prospect is more definite. The passive radiation refrigeration material can be widely applied to the fields of cooling coatings, mobile phone heat dissipation films, energy-saving green home decoration coatings, condensate water preparation devices, cooling fabrics or heat dissipation packaging films and the like.
Detailed Description
The present invention is further illustrated by the following examples, which are intended to be purely exemplary and are not intended to limit the scope of the invention.
1. Raw materials
(1) Matrix resin
Polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polyvinyl fluoride, polyvinylidene fluoride-co-hexafluoropropylene, epoxy resin E-44 and curing agent were purchased from Guangdong Wengjiang chemical Co., Ltd and used as they were.
(2) Modified graphene
Wherein the graphite oxide of the raw material is prepared by natural graphite through a Hummers method. Natural graphite is purchased from Qingdao Haidan graphite, Inc. with model number LC-180. Preparing an aqueous solution 1mg/ml, adding glucose which is 100 times of the mass of the graphene oxide participating in the reaction into the aqueous solution, and carrying out ultrasonic stirring for 1 hour to obtain a mixed solution 1. Adding a salt solution of high-reflectivity particles with the mass 5 times that of graphene oxide into a proper amount of water, ultrasonically stirring for 30min, and adding 0.5mol/L ammonia water to obtain a reaction solution 2. Mixing the mixed solution 1 and the reaction solution 2, ultrasonically stirring for 30min, adding into a reaction kettle, reacting at 100 ℃ for 1h, and reacting at 180 ℃ for 8 h. And washing the product with deionized water after reaction, and carrying out thermal reduction and defect repair on the product at the high temperature of 600 ℃ for 1h to obtain the ground defect graphene grafted with the high-reflectivity particles. The obtained graphene grafted with the high-reflectivity particles is treated with a surface treating agent KH-550 to obtain the target modified graphene.
The salt solutions and treatment means of different high-reflectivity particles are utilized to obtain modified graphene with different parameters, and the performances are shown in the following table 1. Wherein the sheet diameter dimensions D50, D10, D90 of the graphene were measured by a volume reference mode of particle size distribution test, the thickness was measured by an Atomic Force Microscope (AFM), and the diameter dimensions of the grafted high-reflectance particles were measured by a microscopy method.
Table 1: list of modified graphene
Figure BDA0002561937280000091
Glucose: chemical reagents of the national drug group, Inc. can be used directly.
Dopamine hydrochloride: chemical reagents of the national drug group, Inc. can be used directly.
Gold bromide: chemical reagents of the national drug group, Inc. can be used directly.
Copper nitrate: chemical reagents of the national drug group, Inc. can be used directly.
Aluminum nitrate: chemical reagents of the national drug group, Inc. can be used directly.
Silicon dioxide (SiO)2): chemical reagents of the national drug group, Inc. can be used directly.
Silane coupling agent KH-550: shanghai Aladdin reagent, Inc., as it is.
(3) Pore-forming agent
Polyethylene glycol-2000 (PEG-2000): chemical reagents of the national drug group, Inc. can be used directly.
Polyvinylpyrrolidone (PVP): chemical reagents of the national drug group, Inc. can be used directly.
(4) Solvent(s)
N, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP) and acetone were purchased from national institutes of chemical reagents, Inc. and used as they were.
(5) Other auxiliaries
Sodium borohydride, lithium borohydride, ammonium chloride, lithium chloride and sodium chloride are all purchased from chemical reagents of national drug group, ltd, and are directly used.
2. Method for determining the relevant properties in the examples according to the invention and in the comparative examples:
A. porosity, pore size range, most probable pore size: nitrogen adsorption apparatus (MicrotracBEL BELPREP-vac II type Japan)
The test method comprises the following steps: weighing 0.1-0.2g of test sample, carrying out high-temperature vacuum treatment to remove adsorbed gas, water and other impurities, and placing the sample into a sample tube after the treatment is finished. The circuit and the gas pipeline of the testing instrument are connected, the testing software on the computer is opened to select the testing mode and input the quality of the sample. The sample tube was attached to the instrument and an incubation tank containing liquid nitrogen was prepared just below it. And (4) operating the machine, vacuumizing after the machine starts to operate, and automatically lifting the heat preservation tank when the vacuum degree is 0 kPa. After the machine runs for more than ten hours, the test is finished, and the porosity, the pore size range and the most probable pore size of the test material can be obtained after test data are derived and calculated.
B. Infrared emissivity: fourier transform infrared spectrometer (BRUKER VERTEX 70 type Germany)
The test method comprises the following steps: firstly, a laser system is utilized to carry out collimation adjustment on a light path system, then the temperature of the black body standard radiation source is controlled to be 50 ℃, after the temperature is stable, an infrared spectrometer is started, and a computer samples to obtain a radiation energy spectrum curve of the black body standard radiation source. And replacing the position of the black body standard radiation source with the manufactured passive radiation refrigeration material, controlling the temperature of the passive radiation refrigeration material to be the same as that of the black body by using a micro heating temperature control system, and repeating the black body radiation sampling process after the temperature is stable to obtain the radiation energy spectrum curve of the test sample. And processing the curves of the test sample and the black body standard sample to obtain the infrared emissivity of the test material.
C. Infrared light reflectance: fourier infrared spectrometer (BRUKER VERTEX 70 type Germany)
The test method comprises the following steps: taking a certain specification of the accompanying sheet, and carrying out fine grinding and polishing on one surface (non-testing surface) of the accompanying sheet, wherein the parallelism is required to be less than or equal to 0.01 mm. And coating the other side (testing side) of the accompanying sheet with the prepared passive radiation refrigeration material, grinding the non-testing side of the accompanying sheet by using No. 240 carborundum, and testing by using a relative measurement method to obtain the reflectivity of the material.
D. Cooling power: infrared heating box (Jiangkai JK-H-420L China)
The test method comprises the following steps: the prepared passive radiation refrigeration material is coated on a copper plate with the thickness of 20cm x 20cm x 1mm, and the thickness of the material is controlled to be 300 mu m. The other side of the copper sheet was attached to a 20cm x 20cm heating bar on top of a 20cm x 20cm x 5cm block of polystyrene foam and connected to a computer controlled power supply. Two thermocouples were placed between the passive radiant cooling material and the copper sheet to measure the temperature of the coating. Thermocouples were also placed around the sample to measure ambient temperature. Then the whole is put into an infrared heating box, and the output power of the infrared heating box is set, so that the light irradiation power in the box is stabilized at 1000W/m2. The cooling power of the material can be obtained by collecting and calculating the temperature data of the ambient temperature and the passive radiation refrigeration material.
Example 1
Weighing 40g of polyvinylidene fluoride (PVDF) as a base resin, adding the base resin into 110g of organic solvent DMAc, starting stirring, and rotating at 2000 rpm;
stirring for 20min, adding pore-forming agent 50g PEG-2000 into the system, adjusting the rotation speed to 4000rpm, and continuing stirring;
stirring for 30min, adding 10g ammonium chloride as a pore size regulator into the system, regulating the rotation speed to 5000rpm, and continuing stirring for 30 min;
adding the modified graphene grafted with the high-reflectivity particles obtained in the preparation example 1 into the solution, keeping the rotating speed unchanged, and stirring for 50min to obtain a uniform mixed solution;
and (3) passing the mixed solution through a conventional dry-wet spinning hollow fiber spinning head, then entering a coagulating bath (mixture of acetone and water, the mass ratio is 9: 1), solidifying, drawing and stretching to obtain the passive radiation refrigeration material, and testing the performance, wherein the specific performance is shown in a table 2-1.
Comparative example 1
The same operation as in example 1 was performed except that modified graphene was not added, to obtain a passive radiation refrigerating material as shown in table 2-1.
Comparative example 2
The same operation as in example 1 was performed except that the modified graphene was changed to graphene to which high-reflectance particles were not grafted (graphene obtained in preparation example 16), to obtain passive radiation refrigeration materials as shown in table 2-1.
Comparative example 3
The same operation as in example 1 was performed except that the modified graphene was changed to graphene grafted with low-and high-reflectance particles (graphene obtained in preparation example 14), to obtain passive radiation refrigeration materials as shown in table 2-1.
Comparative example 4
The same operations as in example 1 were carried out except that the fluorine-containing resin was changed to the epoxy resin E-44 and the curing agent which were not the fluorine-containing resin, to obtain passive radiation refrigeration materials as shown in Table 2-1.
Comparative example 5
The same operation as in example 1 was carried out except that a nonporous material was obtained without adding a porogen to obtain a nonporous structure passive radiation refrigerating material as shown in Table 2-1.
Comparative example 6
The same operation as in example 1 was performed except that the preparation method of the modified graphene was changed to mixing and stirring at normal temperature and pressure instead of hydrothermal reaction, to obtain the passive radiation refrigeration material shown in table 2-1.
Examples 2 to 18
The same operations as in example 1 were carried out except that the modified graphene in example 1 was changed as shown in tables 2 to 2 and 2 to 3 to obtain passive radiation refrigeration materials as shown in tables 2 to 2 and 2 to 3.
Examples 19 to 30
The same operation as in example 1 was performed by varying the content of the modified graphene or the high-reflectivity particles of the material in example 1 as shown in tables 3-1 and 3-2 to obtain the passive radiation refrigeration materials as shown in tables 3-1 and 3-2.
Examples 31 to 39
The same operation as in example 1 was performed by adjusting the porogen in example 1 to adjust the porosity and the most probable pore size of the material as shown in table 4-1 to obtain the passive radiation refrigerating material as shown in table 4-1.
Examples 40 to 43
The same operation as in example 1 was carried out by changing the pore size range of the material in example 1 as shown in Table 4-2 to obtain a passive radiation refrigerating material as shown in Table 4-2.
Examples 44 to 49
The same operation as in example 1 was carried out by changing the fluorine-containing resin of the material in example 1 as shown in Table 5-1 to obtain a passive radiation refrigerating material as shown in Table 5-1.
TABLE 2-1
Figure BDA0002561937280000141
As shown in table 2-1, it can be seen from example 1 and comparative examples 1 to 6 that when the passive radiation refrigeration material simultaneously satisfies the conditions of the present invention, that is, when the material contains graphene, high-reflectivity particles, and a fluorine-containing resin, and has a porous structure with the graphene and the fluorine-containing resin as a skeleton, and the high-reflectivity particles are grafted on the graphene sheet layer, the infrared light reflection efficiency of the passive radiation refrigeration material and the infrared emissivity of the atmospheric window band can be significantly improved at the same time, and the cooling power of the material is improved.
Tables 2 to 2
Figure BDA0002561937280000151
As shown in tables 2-1 and 2-2, it can be seen from the examples 1-10 that, within a certain range, adjusting the sheet diameter and the thickness of the graphene has a small influence on the infrared light reflection efficiency of the passive radiation refrigeration material, and has a significant influence on the infrared emissivity of the atmospheric window band. When the graphene sheet diameter is too small, a heat conduction channel is not easy to form, and when the graphene sheet diameter is too large, agglomeration is easy to occur. And the thicker the graphene thickness, the poorer the heat conductivity. The infrared emissivity of the atmospheric window wave band is increased under the condition of good thermal conductivity of graphene, and the cooling power is increased.
Tables 2 to 3
Figure BDA0002561937280000161
As shown in tables 2-1 and 2-2, it can be seen from the combination of examples 1 and 11-18 that, within a certain range, the adjustment of the type and the particle diameter of the high-reflectivity particles has little influence on the infrared emissivity of the atmospheric window band of the passive radiation refrigeration material, and has a significant influence on the infrared light reflection efficiency. The kind of the high-reflectivity particles can directly influence the reflection effect of light, and meanwhile, when the high-reflectivity particles are within a certain diameter range, the infrared light reflection effect is obvious. The higher the reflectivity of the high reflectivity particles, the better the cooling power.
TABLE 3-1
Figure BDA0002561937280000171
As shown in tables 2-1 and 3-1, by combining example 1, examples 19-24, and comparative example 1, it can be seen that, within a certain range, the addition of the modified graphene increases the infrared emissivity of the material in the atmospheric window band (the infrared reflection efficiency of the material is less affected), but after exceeding the range, the content of the graphene is too high, and an agglomeration phenomenon may occur, so that the dispersibility of the graphene in the material is reduced, and at this time, the agglomeration may cause local defects of the material, and thus, the performance of the material may be reduced by adding a large amount of graphene. After the modified graphene is added into the material, the infrared emissivity of the atmospheric window wave band of the material is increased, and the cooling power is increased.
TABLE 3-2
Figure BDA0002561937280000181
As shown in tables 2-1 and 3-2, in combination with examples 1, 25-30 and 2, it is known that the addition of the high-reflectance particles within a certain range improves the infrared light reflection efficiency of the material (the influence on the infrared emissivity of the material in the atmospheric window band is small), but when the high-reflectance particles exceed the range, the content of the high-reflectance particles is too high, which may affect the formation of the porous material, and thus the addition of a large amount of the high-reflectance particles may adversely reduce the performance of the material. When the material is added with the high-reflectivity particles, the infrared light reflection efficiency of the material is increased, and the cooling power is increased.
TABLE 4-1
Figure BDA0002561937280000191
As shown in tables 2-1 and 4-1, in combination with examples 1 and 31-34, it can be seen that the porosity and the most probable pore size of the passively radiated refrigeration material have a significant effect on the infrared light reflection efficiency of the material (the effect on the infrared emissivity of the material in the atmospheric window band is small). The higher the porosity of the material in a certain range, the higher the infrared light reflection efficiency of the material, and the higher the cooling efficiency. When the porosity is too high, the moldability of the polymer is affected, and the properties are affected accordingly. In the case of examples 1 and 35 to 39, it is found that the material having the most probable pore diameter in a specific range has high infrared light reflection efficiency and good cooling efficiency.
TABLE 4-2
Figure BDA0002561937280000201
As shown in tables 2-1 and 4-2, in combination with examples 1 and 40-43, it can be seen that the change of the aperture range of the passive radiation refrigeration material also has a significant effect on the infrared light reflection efficiency of the material (has a small effect on the infrared emissivity of the atmospheric window band of the material). When the aperture range of the material is in a specific range, the infrared light reflection efficiency of the material is high, and the cooling efficiency is high.
TABLE 5-1
Figure BDA0002561937280000211
As shown in tables 2-1 and 5-1, the passive radiation refrigeration materials prepared by different fluorine-containing resins are combined with examples 1, 44-49 and comparative example 4 to improve the cooling power of the infrared emissivity of the material in the atmospheric window band, and the improvement effect is obvious compared with the improvement effect of the material which is usually not prepared by fluorine-containing resins.

Claims (12)

1. A passive radiation refrigeration material, characterized by: the material comprises modified graphene, high-reflectivity particles and fluorine-containing resin, and has a porous structure with the modified graphene and the fluorine-containing resin as frameworks, wherein the high-reflectivity particles are grafted on the modified graphene sheet layer.
2. The passive radiant refrigerant material as set forth in claim 1 wherein: the porosity of the material is 60-80%.
3. The passive radiant refrigerant material as set forth in claim 1 wherein: the pore size of the material is in the range of 0.1-1 μm.
4. The passive radiant refrigerant material as set forth in claim 1 wherein: the pore size of the material is 200-400nm, and the pore size of the material is measured by a nitrogen adsorption instrument.
5. The passive radiant refrigerant material as set forth in claim 1 wherein: the content of the high-reflectivity particles accounts for 0.05-0.3 wt% of the material.
6. The passive radiant refrigerant material as set forth in claim 1 wherein: the content of the modified graphene accounts for 0.1-0.5 wt% of the material.
7. The passive radiant refrigerant material as set forth in claim 1 wherein: the sheet diameter of the modified graphene is 2-50 μm.
8. The passive radiant refrigerant material as set forth in claim 1 wherein: the thickness of the modified graphene is 0.4-12 nm.
9. The passive radiant refrigerant material as set forth in claim 1 wherein: the fluorine-containing resin is more than one selected from polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polyvinyl fluoride and polyvinylidene fluoride-co-hexafluoropropylene.
10. The passive radiant refrigerant material as set forth in claim 1 wherein: the high-reflectivity particles are more than one selected from silver, gold, copper, aluminum and silicon dioxide.
11. The passive radiant refrigerant material as set forth in claim 1 wherein: the diameter dimension D10 of the high-reflectivity particles grafted on the modified graphene sheet layer is 0.1 μm, D50 is 0.5 μm, and D90 is 1 μm.
12. An article comprising the passive radiation cooling material of any of claims 1-11, wherein: the product is a cooling coating, a mobile phone heat dissipation film, an energy-saving green home decoration coating, a condensed water preparation device, a cooling fabric or a heat dissipation packaging film.
CN202010617668.6A 2020-06-30 2020-06-30 Passive radiation refrigerating material and product thereof Pending CN113862815A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117567878A (en) * 2024-01-11 2024-02-20 中稀易涂科技发展有限公司 High-performance porous radiation refrigeration filler and preparation method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117567878A (en) * 2024-01-11 2024-02-20 中稀易涂科技发展有限公司 High-performance porous radiation refrigeration filler and preparation method thereof
CN117567878B (en) * 2024-01-11 2024-04-05 中稀易涂科技发展有限公司 High-performance porous radiation refrigeration filler and preparation method thereof

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