CN114806514A - Method for preparing discontinuous scattering reinforced hole-sphere composite polymer-based radiation refrigeration material by adopting template method - Google Patents

Abstract

A method for preparing a non-continuous scattering-strengthened hole-ball composite polymer-based radiation refrigeration material by a template method relates to the field of material science and technology, in particular to a preparation method of a radiation refrigeration material. The purpose of the present invention is to solve the problem that the radiation refrigeration material prepared in the prior art has an unenvironmental preparation method or poor emission performance in the atmospheric window area. Key points of the method: preparing polymer mixture; molding to obtain crude radiation refrigeration material; removing porogen to obtain discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material. Advantages: The reflectivity R of the solar spectrum (0.3μm～1μm) can reach 68%. Compared with a single porous material, the emissivity in the atmospheric window band (8μm～13μm) is significantly improved; and the cooling effect at night can be as low as 5.8℃. The invention is mainly used for preparing discontinuous scattering reinforced porous ball composite polymer-based radiation refrigeration material.

Description

Method for preparing discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material by template method

technical field

The invention relates to the technical field of material science, in particular to a preparation method of a radiation refrigeration material.

Background technique

my country's building energy consumption accounts for a large proportion of the total energy consumption of the whole society, of which air-conditioning energy consumption accounts for 30% to 60% of the total energy consumption of buildings. And it is expected that the global energy consumption for cooling will be doubled in 2050. Therefore, in order to reduce the use of active air conditioning equipment, the development of new zero-carbon passive cooling technology is crucial for building energy conservation.

Radiant cooling has received extensive attention as a new type of passive cooling technology without energy consumption. The ideal new material for daytime radiation refrigeration radiates its own heat into the huge cold source in outer space through the atmospheric window (8-13 μm) without consuming any electricity or heat energy, which is of great significance for reducing refrigeration energy consumption and achieving zero-carbon environmental protection. At present, the common radiation refrigeration materials mainly include multi-layer structures, metamaterials with periodic surface structures, randomly distributed particle structures, and porous structures. Among them, porous structure materials stand out for their advantages of good refrigeration effect, simple preparation method, low cost, and large-scale preparation, and become the radiation refrigeration material with the most application and future commercialization prospects. However, for the current porous materials, there are still problems such as unfriendly preparation methods and low atmospheric window emissivity, which limit their practical application.

China has published a patent "A superhydrophobic self-cleaning radiation cooling film and its preparation method" (application publication number: CN110483924A), which uses a phase inversion method to prepare a film with a micro-nano dual porous structure. The organic solvents such as acetone and tetrahydrofuran used in this way are toxic and volatile, and are not environmentally friendly.

China has published a patent "a porous polydimethylsiloxane radiation refrigeration material and its preparation method" (application publication number: CN113072737A), this method first synthesizes micron-scale NaCl porogen, by controlling the micron-scale NaCl porogen The size and dosage of the synthetic porous PDMS are used to control the distribution and size of the pores in the synthetic porous PDMS. Although the pores of the material can scatter the light in the solar spectral band and isolate the heat exchange between the heat sink and the surrounding environment, the material emits properties in the atmospheric window region. poor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem that the radiation refrigeration material prepared by the prior art has an unenvironmental preparation method or poor emission performance in the atmospheric window region, and provides a template method to prepare a non-continuous scattering enhanced hole-ball composite polymer-based radiation Methods of refrigeration materials.

The method for preparing a discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material by a template method is specifically completed according to the following steps:

1. Preparation of polymer mixed liquid: after fully mixing the polymer prepolymer and the curing agent, vacuumize in a vacuum machine to eliminate air bubbles to prepare a polymer mixed liquid; the volume of the polymer prepolymer and the curing agent The ratio is 10:(1～6);

2. Forming: first, mix the porogen and the inorganic microsphere material uniformly and then spread them in the container, then pour the polymer mixture obtained in step 1 into the container evenly, and then place it in a vacuum machine to vacuumize to eliminate air bubbles, Finally, solidify and form to obtain a crude radiation refrigeration material; the volume fraction of the porogen in the crude radiation refrigeration material is 30% to 60%; the volume fraction of the inorganic microsphere material in the crude radiation refrigeration material is 6% to 20% %;

3. Removal of the porogen: the crude radiation refrigeration material is immersed in deionized water and heated to remove the porogen, and then placed in an oven for drying to obtain a non-continuous scattering-enhanced pore-ball composite polymer-based radiation refrigeration material. The thickness of the discontinuous scattering-enhanced hole-ball composite polymer-based radiation refrigeration material is 400 μm to 5 mm.

Advantages of the present invention:

1. The discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material prepared by the present invention has a porous scatterer and a microsphere scatterer, and the porous scatterer has a strong Mie scattering effect, which can strongly scatter the light in the solar spectrum band, And the pores in it can isolate the heat exchange between the scatterer and the surrounding environment. The microsphere scatterers can not only strongly scatter the light in the solar spectral band through the Mie scattering effect, but also can strongly emit the light in the atmospheric window band through the surface phonon polarization resonance effect, so as to achieve the effect of daytime radiation cooling.

2. The discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material prepared by the present invention has a solar spectrum (0.3 μm-1 μm) reflectance R of 68%. Compared with a single porous material (such as Example 3), The non-continuous scattering-strengthened hole-ball composite polymer-based radiation refrigeration material prepared by the invention significantly increases the emissivity in the atmospheric window band (8 μm-13 μm); and the cooling effect at night can be as low as 5.8°C.

3. The discontinuous scattering-strengthened porous-ball composite polymer-based radiation refrigeration material prepared by the invention has a single-layer membrane structure, which is simple in structure and good in stability.

Fourth, the preparation method of the present invention is simple in operation, low in cost, environmentally friendly, and can be prepared and applied on a large scale.

Description of drawings

Fig. 1 is a real photo of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material obtained in Example 1;

Fig. 2 is an emissivity spectrogram in the atmospheric window region, in which A represents the atmospheric window region emissivity spectrogram of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material prepared in Example 1, and B represents the emissivity spectrogram in the atmospheric window region prepared in Example 2 The atmospheric window region emissivity spectrum of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material, C represents the atmospheric window region emissivity spectrum of the pure porous material prepared in Comparative Example 1;

FIG. 3 is a reflectance spectrum in the solar spectral region of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material obtained in Example 1. FIG.

Detailed ways

Embodiment 1: This embodiment is a method for preparing a discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material by a template method, which is specifically completed according to the following steps:

1. Preparation of polymer mixed liquid: after fully mixing the polymer prepolymer and the curing agent, vacuumize in a vacuum machine to eliminate air bubbles to prepare a polymer mixed liquid; the volume of the polymer prepolymer and the curing agent The ratio is 10:(1～6);

2. Forming: first, mix the porogen and the inorganic microsphere material uniformly and then spread them in the container, then pour the polymer mixture obtained in step 1 into the container evenly, and then place it in a vacuum machine to vacuumize to eliminate air bubbles, Finally, solidify and form to obtain a crude radiation refrigeration material; the volume fraction of the porogen in the crude radiation refrigeration material is 30% to 60%; the volume fraction of the inorganic microsphere material in the crude radiation refrigeration material is 6% to 20% %;

3. Removal of the porogen: the crude radiation refrigeration material is immersed in deionized water and heated to remove the porogen, and then placed in an oven for drying to obtain a non-continuous scattering-enhanced pore-ball composite polymer-based radiation refrigeration material. The thickness of the discontinuous scattering-enhanced hole-ball composite polymer-based radiation refrigeration material is 400 μm to 5 mm.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the polymer prepolymer in step 1 is an epoxy resin prepolymer, a polyester resin prepolymer, and a polyacrylate resin prepolymer , a polyamide resin prepolymer, a polyurethane resin prepolymer, a polyolefin resin prepolymer, a fluororesin prepolymer or a silicone resin prepolymer. Others are the same as the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that the curing agent in step 1 is benzoyl peroxide, azobisisobutyronitrile, methyl ethyl ketone peroxide and triethylenediamine one or more of them. Others are the same as in the first or second embodiment.

Embodiment 4: One of the differences between this embodiment and Embodiments 1 to 3 is that in step 1, the vacuum is evacuated in a vacuum machine to a degree of vacuum of 0.02 MPa to 0.04 MPa, and when the degree of vacuum is 0.02 MPa to 0.04 MPa Eliminate air bubbles for 0.8h to 1.5h. Others are the same as those in Embodiments 1 to 3.

Embodiment 5: The difference between this embodiment and Embodiments 1 to 4 is that the porogen in step 2 is one or both of NaCl and sugar. Others are the same as the specific embodiments 1 to 4.

Embodiment 6: The difference between this embodiment and Embodiments 1 to 5 is that the inorganic microsphere materials described in step 2 are SiO ₂ powder, BaSO ₄ powder, CaCO ₃ powder, MgO powder, Al ₂ O ₃ powder , one or more of Si ₃ N ₄ powder, titanium dioxide powder, talc powder, aluminum silicate powder and ceramic powder, and the particle size of the inorganic microsphere material is 0.4 μm to 2 μm. Others are the same as the specific embodiments 1 to 5.

Embodiment 7: One of the differences between this embodiment and Embodiments 1 to 6 is that: in step 2, the vacuum is placed in a vacuum machine, and the vacuum degree is 0.02MPa to 0.04MPa, and the vacuum degree is 0.02MPa to 0.04MPa. Remove air bubbles for 0.8h to 1.5h. Others are the same as the specific embodiments 1 to 6.

Embodiment 8: This embodiment differs from Embodiments 1 to 7 in that: in step 2, curing is performed at a temperature of 80-120°C. Others are the same as the specific embodiments 1 to 7.

Embodiment 9: This embodiment differs from Embodiments 1 to 8 in that: in step 3, the crude radiative refrigeration material is immersed in deionized water, and heated at a temperature of 40-80°C for 2h-8h. Others are the same as the specific embodiments 1 to 8.

Embodiment 10: This embodiment differs from Embodiments 1 to 9 in that: in step 3, drying is performed at a temperature of 50 to 100° C. for 0.5 h to 2 h. Others are the same as the specific embodiments 1 to 9.

The content of the present invention is not limited to the content of the above-mentioned embodiments, and a combination of one or more specific embodiments can also achieve the purpose of the invention.

Adopt following experiment to verify the effect of the present invention:

Embodiment 1: The method for preparing discontinuous scattering-enhanced porous spherical composite polymer-based radiation refrigeration material by template method, which is specifically completed according to the following steps:

1. Preparation of polymer mixture: After fully mixing the polymer prepolymer and curing agent, vacuumize in a vacuum machine until the vacuum degree is 0.02MPa, and eliminate bubbles at a vacuum degree of 0.02MPa for 1 hour to obtain a polymer The volume ratio of the polymer prepolymer to the curing agent is 10:1;

2. Forming: first mix the porogen and the inorganic microsphere material uniformly and then spread them in the container, then pour the polymer mixture obtained in step 1 into the container uniformly, and then place it in a vacuum machine to vacuumize until the vacuum is reached. The temperature is 0.02MPa, the bubbles are eliminated at a vacuum degree of 0.02MPa for 1 hour, and finally the temperature is 100 °C for curing and molding to obtain a crude radiation refrigeration material; the volume fraction of the porogen in the crude radiation refrigeration material is 50%; The volume fraction of inorganic microsphere material in the crude radiation refrigeration material is 13%;

3. Removal of porogen: Immerse the crude radiation refrigeration material in deionized water, heat it at 80°C for 8 hours to remove the porogen, then put it in an oven, and dry it at 80°C for 1 hour to obtain discontinuous A scattering-enhanced hole-ball composite polymer-based radiation refrigeration material, the thickness of the discontinuous scattering-enhanced hole-ball composite polymer-based radiation refrigeration material is 2.5 mm.

The polymer prepolymer described in step 1 of this example is a PDMS prepolymer.

The curing agent described in step 1 of this embodiment is benzoyl peroxide.

The porogen in the second step of this example is sugar.

In the second step of this embodiment, the inorganic microsphere material is SiO ₂ powder, and the average particle size of the inorganic microsphere material is 4 μm.

Figure 1 is a real photo of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material obtained in Example 1. By performing pore amplification analysis on the photo, the discontinuous-scattering-enhanced porous-spherical composite polymer-based radiation obtained in Example 1 The average pore size of the refrigeration material is about 280 μm.

Optical fiber spectrometer (CHS-5000/200μm) was used to detect the reflectivity of the discontinuous scattering-enhanced hole-ball composite polymer-based radiation refrigeration material obtained in Example 1. The results are shown in Figure 3, which is Example 1. Figure 3 shows that the reflectance R in the solar spectrum (0.3μm-1μm) range can reach 68%.

A thermocouple (VC6801) was used to test the cooling effect of the discontinuous scattering-enhanced porous-ball composite polymer-based radiation refrigeration material obtained in Example 1, and its nighttime cooling effect was as low as 5.8°C.

Embodiment 2: The method for preparing discontinuous scattering-enhanced porous spherical composite polymer-based radiation refrigeration material by template method, which is specifically completed according to the following steps:

1. Preparation of polymer mixture: After fully mixing the polymer prepolymer and curing agent, vacuumize in a vacuum machine until the vacuum degree is 0.02MPa, and eliminate bubbles at a vacuum degree of 0.02MPa for 1 hour to obtain a polymer The volume ratio of the polymer prepolymer to the curing agent is 10:1;

2. Forming: first mix the porogen and the inorganic microsphere material uniformly and then spread them in the container, then pour the polymer mixture obtained in step 1 into the container uniformly, and then place it in a vacuum machine to vacuumize until the vacuum is reached. The temperature is 0.02MPa, the bubbles are eliminated at a vacuum degree of 0.02MPa for 1 hour, and finally the temperature is 100 °C for curing and molding to obtain a crude radiation refrigeration material; the volume fraction of the porogen in the crude radiation refrigeration material is 50%; The volume fraction of the inorganic microsphere material in the crude radiation refrigeration material is 10%;

3. Removal of porogen: Immerse the crude radiation refrigeration material in deionized water, heat it at 80°C for 8 hours to remove the porogen, then put it in an oven, and dry it at 80°C for 1 hour to obtain discontinuous A scattering-enhanced hole-ball composite polymer-based radiation refrigeration material, the thickness of the discontinuous scattering-enhanced hole-ball composite polymer-based radiation refrigeration material is 2.5 mm.

The polymer prepolymer described in step 1 of this example is a PDMS prepolymer.

The curing agent described in step 1 of this embodiment is benzoyl peroxide.

The porogen in the second step of this example is sugar.

In the second step of this embodiment, the inorganic microsphere material is SiO ₂ powder, and the average particle size of the inorganic microsphere material is 4 μm.

Comparative Example 1: Comparison of materials without inorganic microspheres added:

1. Preparation of polymer mixture: After fully mixing the polymer prepolymer and curing agent, vacuumize in a vacuum machine until the vacuum degree is 0.02MPa, and eliminate bubbles at a vacuum degree of 0.02MPa for 1 hour to obtain a polymer The volume ratio of the polymer prepolymer to the curing agent is 10:1;

2. Forming: firstly spread the porogen in the container, then pour the polymer mixture obtained in step 1 into the container evenly, and then place it in a vacuum machine to vacuum until the degree of vacuum is 0.02MPa, and the degree of vacuum is 0.02MPa. The bubbles were eliminated at 0.02 MPa for 1 h, and finally the temperature was 100 °C for curing and molding to obtain a crude radiation refrigeration material; the volume fraction of the porogen in the crude radiation refrigeration material was 50%;

3. Removal of porogen: Immerse the crude radiation refrigeration material in deionized water, heat it at 80°C for 8 hours to remove the porogen, then put it in an oven, and dry it at 80°C for 1 hour to obtain pure porous material, the thickness of the pure porous material is 2.5mm.

The polymer prepolymer described in step 1 of this example is a PDMS prepolymer.

The curing agent described in step 1 of this embodiment is benzoyl peroxide.

The porogen in the second step of this example is sugar.

The emissivity in the solar spectral region was measured by Fourier spectrometer on the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration materials prepared in Examples 1 and 2 and the pure porous material prepared in Comparative Example 1. The results are shown in the accompanying drawings. 2; Figure 2 is the atmospheric window region emissivity spectrum, in the figure A represents the atmospheric window region emissivity spectrum of the discontinuous scattering enhanced porous-sphere composite polymer-based radiation refrigeration material prepared in Example 1, and B represents the implementation The atmospheric window region emissivity spectrum of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material prepared in Example 2, C represents the atmospheric window region emissivity spectrum of the pure porous material prepared in Comparative Example 1, through Example 1 Compared with Comparative Example 1, the emissivity of the discontinuous scattering-enhanced porous-sphere composite polymer-based radiation refrigeration material prepared by the present invention is significantly improved in the atmospheric window band (8 μm-13 μm).

Claims (10)

1. The method for preparing the discontinuous scattering reinforced hole-sphere composite polymer-based radiation refrigeration material by adopting the template method is characterized by comprising the following steps of:

firstly, preparing a polymer mixed solution: fully and uniformly mixing the polymer prepolymer and the curing agent, and vacuumizing in a vacuum machine to eliminate bubbles to prepare a polymer mixed solution; the volume ratio of the polymer prepolymer to the curing agent is 10 (1-6);

secondly, forming; uniformly mixing a pore-foaming agent and an inorganic microsphere material, then flatly paving the mixture in a container, uniformly pouring the polymer mixture obtained in the step one into the container, then placing the container in a vacuum machine for vacuumizing to eliminate bubbles, and finally performing curing molding to obtain a crude product of the radiation refrigeration material; the volume fraction of the pore-foaming agent in the crude product of the radiation refrigeration material is 30-60%; the volume fraction of the inorganic microsphere material in the crude product of the radiation refrigeration material is 6-20%;

thirdly, removing the pore-foaming agent: and soaking the crude product of the radiation refrigeration material in deionized water, heating to remove a pore-forming agent, and then putting the crude product of the radiation refrigeration material into an oven for drying to obtain the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material, wherein the thickness of the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material is 400 mu m-5 mm.

2. The method for preparing a discontinuous scattering-reinforced hole-sphere composite polymer-based radiation refrigeration material according to claim 1, wherein in the step one, the polymer prepolymer is one of epoxy resin prepolymer, polyester resin prepolymer, polyacrylate resin prepolymer, polyamide resin prepolymer, polyurethane resin prepolymer, polyolefin resin prepolymer, fluororesin prepolymer or silicone resin prepolymer.

3. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method as claimed in claim 2, wherein the curing agent in the step one is one or more of benzoyl peroxide, azobisisobutyronitrile, methyl ethyl ketone peroxide and triethylene diamine.

4. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method as claimed in claim 3, wherein in the step one, the vacuum machine is vacuumized until the vacuum degree is 0.02MPa to 0.04MPa, and bubbles are eliminated for 0.8h to 1.5h under the vacuum degree of 0.02MPa to 0.04 MPa.

5. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method according to claim 1 or 4, wherein the pore-forming agent in the second step is one or both of NaCl and sugar.

6. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method as claimed in claim 5, wherein the inorganic microsphere material in the second step is SiO ₂ Powder, BaSO ₄ Powder, CaCO ₃ Powder, MgO powder, Al ₂ O ₃ Powder, Si ₃ N ₄ One or more of powder, titanium dioxide, talcum powder, aluminum silicate powder and ceramic powder, and the particle size of the inorganic microsphere material is 0.4-2 mu mm。

7. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method according to claim 6, wherein in the second step, the material is placed in a vacuum machine for vacuum pumping until the vacuum degree is 0.02MPa to 0.04MPa, and bubbles are eliminated for 0.8h to 1.5h under the vacuum degree of 0.02MPa to 0.04 MPa.

8. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method as claimed in claim 7, wherein the curing is carried out at a temperature of 80-120 ℃ in the second step.

9. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method according to claim 1 or 8, characterized in that in the third step, the crude product of the radiation refrigeration material is immersed in deionized water and heated at the temperature of 40-80 ℃ for 2-8 h.

10. The method for preparing the discontinuous scattering-reinforced pore-sphere composite polymer-based radiation refrigeration material by adopting the template method according to claim 9, wherein the drying is carried out at the temperature of 50-100 ℃ for 0.5-2 h in the third step.

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