Semi-automatic temperature-regulated radiative cooling film and method of making the same

Abstract

The application relates to a semi-automatic temperature-regulated radiation refrigeration film and a preparation method thereof. The scheme comprises the following steps: preparing a polymer mixed solution: stirring 30-70 parts of a polymer, 0-10 parts of a crosslinking agent, 0.1-1 part of an ultraviolet absorber, 0.1-1 part of an anti-aging agent and 15-35 parts of a first organic solvent to obtain a uniform polymer first organic solution at room temperature; preparing a treatment mixed solution: stirring 60-70 parts of a monomer, 0.5-10 parts of an initiator and 20-39.5 parts of a second organic solvent to obtain a uniform treatment mixed solution at room temperature; S10, performing electrospinning on the polymer mixed solution and then solidifying until a porous polymer film is obtained; S20, immersing the porous polymer into the treatment mixed solution, wiping after immersion for a set time and placing in a heating environment for heating until a radiation refrigeration film is obtained. The application can meet the demand of regulating temperature according to needs in winter and summer.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of radiation refrigeration material science, in particular to a semi-automatic temperature-regulating radiation refrigeration film and a preparation method thereof. BACKGROUND

[0002] Building energy consumption accounts for more than 30% of the total global energy consumption and about 20% of the global greenhouse gas emissions. Nearly half of the building energy consumption is used for heating and refrigeration of buildings. With the urbanization and improvement of living standards, building temperature control energy consumption will further increase. As a new type of building air conditioning technology, radiation refrigeration can realize temperature reduction without additional energy consumption by enhancing the reflectivity of sunlight (0.3-2.5 microns) and transmitting heat from the object surface to the outer space at -270 DEG C through radiation heat exchange in the atmospheric window (8-13 microns).

[0003] However, the existing radiation refrigeration technology lacks seasonal selectivity and continuously releases heat in winter, which is in a refrigeration state, thereby greatly increasing the energy consumption for heating in winter. The nearly ten times difference between the incident solar radiation power (about 1000 W / m 2 ) and the radiation refrigeration power (about 100 W / m 2 ) makes it difficult to efficiently regulate the ATW, greatly limiting the promotion and use of the radiation refrigeration technology.

[0004] Therefore, there is an urgent need for a semi-automatic temperature-regulating radiation refrigeration film and a preparation method thereof to solve the problems existing in the prior art. SUMMARY

[0005] The application aims to provide a semi-automatic temperature-regulating radiation refrigeration film and a preparation method thereof to solve the above problems in the prior art.

[0006] To achieve the above application purposes, the application adopts the following technical solutions: the preparation method of the semi-automatic temperature-regulating radiation refrigeration film comprises the following steps:

[0007] S00, preparing a polymer mixed solution: 30-70 parts of a polymer, 0-10 parts of a crosslinking agent, 0.1-1 part of an ultraviolet absorber, 0.1-1 part of an anti-aging agent and 15-35 parts of a first organic solvent are taken according to the mass fraction, and the mixture is stirred at room temperature to obtain a uniform polymer mixed solution;

[0008] Preparation of a treatment mixed solution: 60-70 parts of a monomer, 0.5-10 parts of an initiator and 20-39.5 parts of a second organic solvent are taken according to the mass fraction, and the mixture is stirred at room temperature to obtain a uniform treatment mixed solution;

[0009] The polymer is one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, polydimethylsiloxane or a mixture of two of them; the monomer is any one of acrylic acid, oleic acid, 6-acryloylamino caproic acid, 3-acrylamido-3-methyl butyric acid, N-methyl acryloyl glycine or a mixture of two of them.

[0010] S10, solidifying the polymer mixed solution after electrospinning to obtain a porous polymer film;

[0011] S20, immersing the porous polymer into the treatment mixed solution, wiping and placing in a heating environment after immersion for a set time to obtain a radiation cooling film with semi-automatic temperature adaptive regulation.

[0012] Working principle and beneficial effects: 1. Compared with the prior art, the present application modifies the porous polymer surface with carboxyl or hydroxyl groups. Under pressure, the carboxyl groups on the polymer chains between the pores combine with each other due to hydrogen bonding, realizing pore closure. The white porous film is converted into a transparent closed pore film. When the external tension exceeds the hydrogen bonding force, the hydrogen bonds are broken, and the polymer film returns to a porous state. Therefore, the summer cooling (cooling) coating and winter warming (warming) coating can be freely converted. That is, the radiation cooling film with semi-automatic temperature adaptive regulation prepared by the present application has a high solar spectrum reflectivity of 94% and a high long-wave infrared emissivity of 95% in the white porous cooling state. The radiation cooling effect is stable and good. Specifically, the surface cooling is 26°C and the internal cooling is 5°C at an ambient temperature of 33°C. In the closed pore transparent state, the light transmittance is as high as 98%, and the sunlight can be almost completely transmitted, realizing warming. Specifically, the surface warming is 22°C and the indoor warming is 10°C at an ambient temperature of 10°C.

[0013] Further, in the S00 step, the crosslinking agent is one of 1,1,1-tris(2-heptamethylcyclotetrasiloxane-ethyl)-methylsilane, bis(septamethylcyclotetrasiloxanyl)ethane, tin catalyst and platinum catalyst.

[0014] Further, in the S00 step, the ultraviolet absorber is one of phenyl salicylate, UV-531 and RMB.

[0015] Further, in the S00 step, the anti-aging agent is one or a combination of more than one of triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester and tris[2,4-di-tert-butylphenyl] phosphite.

[0016] Further, in the S00 step, the first organic solvent is any one of tetrahydrofuran, acetone, ethyl acetate, dichloromethane or a mixture of two of them.

[0017] Further, in the S00 step, the initiator is any one of azobisisobutyronitrile, azobisisoheptyl nitrile, and azobisisopentyl nitrile.

[0018] Further, in the S00 step, the second organic solvent is one of methanol, ethanol, tetrahydrofuran, and N,N-dimethylformamide or a mixture of two thereof.

[0019] Further, in the S10 step, the polymer mixed solution is injected into a syringe, electrospun through an electrospinning system, and then placed in an environment of 25-100°C for solidification for 0.5-10 hours to obtain a porous polymer film.

[0020] The semi-automatic temperature adaptive radiation cooling film prepared by the above-mentioned preparation method of the semi-automatic temperature adaptive radiation cooling film has a stimulus-responsive porous layer, which is a porous layer under tension stimulation and is used for reflecting sunlight to achieve cooling, and is a solid layer in a light-transparent state under pressure stimulation and is used for achieving heating.

[0021] Further, the radiation cooling film has small pores with a pore size of 0.1-5 μm and large pores with a pore size of 10-50 μm, and the thicknesses of both are 0.2-1 mm.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The semi-automatic temperature adaptive radiation cooling film of the present application has the ability of temperature selective regulation, and can realize the reversible conversion of the porous film (cooling) and the transparent film (heating) through simple external force stimulation. It has superior cooling capacity when it is hot, and good heating capacity when the temperature is relatively low.

[0024] 2. The semi-automatic temperature adaptive radiation cooling film of the present application is distributed with rich micro-nano pore structures, and has a porosity of more than 78%, high reflection and high emission characteristics in the solar spectrum and atmospheric window region respectively, stable and good radiation cooling effect. Moreover, the temperature regulation capacity (solar reflectivity) can be regulated step by step by applying different pressures, realizing the regulation in the range of 5-94%. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flow chart of an embodiment of the present application;

[0026] Figure 2 is a schematic diagram of the porous and closed pore state transition principle of the present application;

[0027] Figure 3 is a SEM image of the porous and closed pore state of the semi-automatic temperature adaptive radiation cooling film in Example 1.

[0028] Figure 4 is a plot of the solar reflectance of the semi-automatically temperature-adapted radiative cooling film in Example 2 in the porous and closed-porous states;

[0029] Figure 5 is a plot of the visible light transmittance of the semi-automatically temperature-adapted radiative cooling film in Example 3 in the porous and closed-porous states;

[0030] Figure 6 is a plot of the outdoor temperature variation of the semi-automatically temperature-adapted radiative cooling film in Example 4 in the porous state;

[0031] Figure 7 is a plot of the outdoor temperature variation of the semi-automatically temperature-adapted radiative cooling film in Example 3 in the closed-porous state;

[0032] Figure 8 is a plot of the reflectance of the semi-automatically temperature-adapted radiative cooling film in Example 5 as a function of the external applied pressure. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0034] The drawings of the present application are obtained by using the following experimental conditions: the reflectance R and the transmittance T of the radiative cooling film in each embodiment in the 7 μm-14 μm wave band are tested, and the emissivity E = 1-R-T is calculated.

[0035] The testing instrument is PerkinElmer, Spotlight 200i; the reflectance of the radiative cooling film in each embodiment in the 300 nm-2500 nm wave band is tested, and the testing instrument is Lambda 950 type UV / Vis / NIR Spectrometer (ultraviolet / visible / near-infrared spectrophotometer).

[0036] The prepared passive radiative cooling film is fixed on an aluminum alloy plate (15 cm long x 15 cm wide x 1 mm thick) of a self-built cooler, and the ambient temperature is measured by a heat resistance placed in a louver box near the cooler. Because aluminum alloy is a good conductor of heat, the surface temperature of the coating is equal to the aluminum alloy temperature, and the surface temperature of the coating can be measured by a heat resistance inserted into the circular hole in the middle of the aluminum alloy plate. The solar irradiance is measured by an irradiance meter. The above-mentioned data is transmitted to the computer terminal by wireless transmission.

[0037] Example 1

[0038] The preparation method of the semi-automatic temperature-regulated radiative cooling film comprises the following steps:

[0039] 60 parts of octamethylcyclotetrasiloxane (D4), 8 parts of 1,1,1-tris(2-heptamethylcyclotetrasiloxane-ethyl)-methylsilane, 0.5 parts of phenyl salicylate, 0.5 parts of triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and 31 parts of tetrahydrofuran are added into a container, and a uniform mixed solution is obtained after stirring at room temperature 25°C. Then, the solution is injected into a 100ml syringe, electrospun, and then placed at 25°C for 5 hours (this range is placed at 60-100°C for 0.5-1 hour) to obtain a porous polyoctamethylcyclotetrasiloxane film.

[0040] 65 parts of acrylic acid, 5 parts of azobisisobutyronitrile and 30 parts of ethanol are stirred at room temperature 25°C to obtain a uniform solution, then the polyoctamethylcyclotetrasiloxane film is immersed in the solution for 2 minutes, taken out and placed on a heating table at 70°C for 20 minutes to obtain a radiative cooling film with semi-automatic temperature adaptive regulation. The porous (cooling) and closed pore (warming) states of the film are observed by SEM to obtain Figure 3 It can be observed that the high-flexibility radiative cooling film with composite pore size prepared by the scheme has small pores with a pore size of 0.1-5um and large pores with a pore size of 15-30um.

[0041] Example 2

[0042] 70 parts of hexamethylcyclotrisiloxane (D3), 7 parts of 1,1,1-tris(2-heptamethylcyclotetrasiloxane-ethyl)-methylsilane, 0.2 parts of phenyl salicylate, 0.3 parts of triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and 22.5 parts of N,N dimethylformamide are added into a container, and a uniform mixed solution is obtained after stirring at room temperature 25°C. Then, the solution is injected into a 100ml syringe, electrospun, and then placed at 100°C for 1 hour to obtain a porous polydimethylsiloxane film.

[0043] 65 parts of 6-acrylamidohexanoic acid, 5 parts of azobisisobutyronitrile and 30 parts of tetrahydrofuran are stirred at room temperature 25°C to obtain a uniform solution, then the porous polydimethylsiloxane film is immersed in the solution for 4 minutes, taken out, the surface is wiped dry, and placed on a heating table at 60°C for 30 minutes to obtain a radiative cooling film with semi-automatic temperature adaptive regulation. The solar reflectance of the porous (cooling) and closed pore (warming) states of the film is shown in Figure 4 , and the visible light transmittance is shown in Figure 5 .

[0044] Example 3

[0045] Into a container, 70 parts of decamethylcyclopentasiloxane (D5), 7 parts of 1,1,1-tris(2-heptamethylcyclosiloxane-ethyl)-methylsilane, 0.2 parts of phenyl salicylate, 0.3 parts of triethylene glycol ether-di(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate and 22.5 parts of N,N dimethylformamide were added to obtain a uniform mixed solution after stirring at room temperature 25°C. Then it was injected into a 100 ml syringe, electrospun, and then placed at 100°C for 1 hour to obtain a porous polydimethylsiloxane film.

[0046] Into a container, 70 parts of acrylic acid, 10 parts of azobisisobutyronitrile, 20 parts of methanol were stirred at room temperature 25°C to obtain a uniform solution, then the porous polydimethylsiloxane film was immersed in the solution for 4 minutes, then taken out, the surface was wiped dry, and placed on a heating table at 60°C for heating for 30 minutes to obtain a radiation cooling film with semi-automatic temperature adaptive regulation, and the performance test results of its porous (cooling) state at different outdoor temperatures are shown in Figure 6 Figure 7

[0047] Example 4

[0048] Into a container, 65 parts of polydimethylsiloxane, 7 parts of platinum catalyst, 0.5 parts of ultraviolet absorber RMB, 0.5 parts of tris[2.4-di-tert-butylphenyl] phosphite and 27 parts of N,N dimethylformamide were added to obtain a uniform mixed solution after stirring at room temperature 25°C. Then it was injected into a 100 ml syringe, electrospun, and then placed at 80°C for 1.5 hours to obtain a porous polydimethylsiloxane film.

[0049] Into a container, 70 parts of oleic acid, 10 parts of azobisisobutyronitrile, 20 parts of methanol were stirred at room temperature 25°C to obtain a uniform solution, then the porous polydimethylsiloxane film was immersed in the solution for 3 minutes, then taken out, the surface was wiped dry, and placed on a heating table at 80°C for heating for 30 minutes to obtain a radiation cooling film with semi-automatic temperature adaptive regulation, and the relationship between its solar reflectivity and external applied pressure is shown in Figure 8

[0050] As shown in Figure 2 ​​​As shown, the principle of the semi-automatic temperature adaptive regulation of the radiation cooling film of the present application is to modify the carboxyl or hydroxyl group on the surface of the porous polymer, under pressure, the carboxyl group on the polymer chain between the pores combines with each other due to hydrogen bonding, realizes the closed pores, and the white porous film is converted into a transparent closed pore film. When the external tension exceeds the hydrogen bonding force, the hydrogen bond is broken, and the polymer film returns to the porous state, so the free conversion of summer cooling (cooling) coating and winter warming (heating) coating can be realized. The average reflectivity of sunlight can be adjusted by applying a pressure of 0-3 MPa, and the average reflectivity of sunlight is 5-94%, and the average infrared emissivity is 88-96%.

[0051] The part of the present application not described in detail is the prior art, so the present application does not describe it in detail. Those skilled in the art should understand that in the disclosure of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above-mentioned terms cannot be understood as a limitation of the present application.

[0052] It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number.

[0053] Although professional terms are used more frequently in this document, the possibility of using other terms is not excluded. The use of these terms is only to facilitate the description and explanation of the essence of the present application; any additional limitation is contrary to the spirit of the present application.

[0054] The present application is not limited to the above best embodiment, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any change in shape or structure, any technical solution with the same or similar to the present application falls within the scope of protection of the present application.

Claims

1. A method for preparing a semi-automatic temperature-regulated radiative cooling film, characterized in that, The method comprises the following steps: S00, preparing a polymer mixed solution: taking 30-70 parts of polymer, 0-10 parts of crosslinking agent, 0.1-1 parts of ultraviolet absorber, 0.1-1 parts of anti-aging agent and 15-35 parts of first organic solvent by mass fraction, stirring at room temperature to obtain a uniform polymer mixed solution; The processing mixed solution is prepared by taking 60-70 parts of monomer, 0.5-10 parts of initiator and 20-39.5 parts of second organic solvent by mass fraction, and stirring at room temperature to obtain a uniform processing mixed solution; The polymer is one of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, polydimethylsiloxane or a mixture of two of them; the monomer is any one of acrylic acid, oleic acid, 6-acryloylaminocaproic acid, 3-acrylamido-3-methylbutyric acid, N-methyl acryloyl glycine or a mixture of two of them; S10, solidifying the polymer mixed solution after electrospinning to obtain a porous polymer film; S20, immersing the porous polymer into the processing mixed solution, wiping after immersion for a set time and heating in a heating environment until a radiation cooling film with semi-automatic temperature adaptive regulation is obtained.

2. The method of claim 1, wherein the temperature of the film is controlled by the user. In the S00 step, the crosslinking agent is one of 1,1,1-tris(2-heptamethylcyclotetrasiloxane-ethyl)-methylsilane, bis(septamethylcyclotetrasiloxane) ethane, tin catalyst and platinum catalyst.

3. The method of claim 1, wherein the temperature-regulating radiative cooling film is prepared by the steps of: In the S00 step, the ultraviolet absorber is one of phenyl salicylate, UV-531 and RMB.

4. The method of claim 1, wherein the temperature-regulating radiative cooling film is prepared by the steps of: In the S00 step, the anti-aging agent is one or a combination of three ethylene glycol ethers-di(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester and tris[2.4-di-tert-butylphenyl] phosphite.

5. The method of claim 1-4, wherein the method further comprises, In the S00 step, the first organic solvent is any one or a mixture of two of tetrahydrofuran, acetone, ethyl acetate and dichloromethane.

6. The method of claim 5, wherein the temperature of the film is controlled by the user. In the S00 step, the initiator is any one of azobis isobutyronitrile, azobis isonitrile and azobis isopentyl nitrile.

7. The method of claim 6, wherein the temperature of the film is controlled by the user. In the S00 step, the second organic solvent is one or a mixture of two of methanol, ethanol, tetrahydrofuran and N,N-dimethylformamide.

8. The method of claim 1-4, wherein the method further comprises, In the S10 step, the polymer mixed solution is injected into a syringe, electrospun by an electrospinning system, and then placed in an environment of 25-100℃ for 0.5-10 hours to obtain the porous polymer film.

9. The semi-automatically temperature-regulated radiative cooling film prepared by the method of any one of claims 1-8, characterized in that, The radiation cooling film has a stimulus-responsive porous layer that responds to tension stimulus to be a porous layer for reflecting sunlight to achieve cooling, and responds to pressure stimulus to be a solid layer in a light-transparent state for achieving heating.

10. The semi-automated thermally regulated radiative cooling film of claim 9, wherein, The radiation cooling film has small pores with a pore size of 0.1-5μm and large pores with a pore size of 10-50μm, and the thickness is 0.2-1mm.

Images