A recyclable polymer-based solar photothermal material and its preparation method and application

Abstract

The present invention provides a method for preparing a recyclable polymer-based solar photothermal material, comprising the following steps: (1) preparing a porous sodium chloride salt template; (2) preparing a polymer precursor mixed solution or prepolymer liquid containing an exchangeable dynamic bond and a photothermal conversion agent; (3) pouring the polymer precursor mixed solution or prepolymer liquid prepared in step (2) into the porous sodium chloride salt template prepared in step (1); (4) heating the system obtained in step (3) to complete a cross-linking polymerization reaction; (5) placing the system obtained in step (4) after the cross-linking polymerization reaction is completed in water and soaking to remove the sodium chloride salt template. The present invention provides a polymer-based solar photothermal material and a preparation method thereof, which have a wide range of material sources, flexible design, low cost, and no pollution; good recycling performance, energy saving and environmental protection, and have good application prospects in solar photothermal interface water evaporators.

Description

Technical field:

[0001] The present application relates to the field of materials, and specifically to a recyclable polymer-based solar thermal material and a preparation method and application thereof. Background technology:

[0002] Freshwater shortages are a global challenge that all countries must address. On the one hand, the total amount of groundwater, riverbed water, and lake water that humans can exploit only accounts for 0.7% of Earth's total water resources. On the other hand, water pollution has rendered a significant amount of freshwater unusable. Seawater accounts for 97.5% of Earth's total water resources, making desalination an effective solution to the freshwater crisis. Currently, cryogenic distillation, multi-stage flash evaporation, and reverse osmosis are the most widely used desalination technologies. However, implementing these desalination technologies in remote and impoverished areas is prohibitively expensive. The demand for low-cost, high-efficiency desalination technologies is growing rapidly. Photothermal water evaporation technology is an environmentally friendly method for energy generation, desalination, and wastewater treatment. It offers unique advantages and broad application prospects in many key industrial sectors, such as steam power generation, sterilization, desalination, and wastewater treatment.

[0003] Currently, there are two main types of materials commonly used for water evaporation at solar-thermal interfaces. The most common type is inorganic nanophotothermal materials, such as metal nanoparticles and carbon-based nanomaterials; the other type is polymer-based photothermal materials. Compared with inorganic nanophotothermal materials, polymer materials have low cost, low thermal conductivity, diverse pore-forming methods, and can be produced on a large scale, making them ideal for practical applications of water evaporation at solar-thermal interfaces. However, polymer materials are generally highly cross-linked thermosets, making them difficult to recycle after disposal, resulting in significant energy waste and environmental pollution.

[0004] In view of this, this invention is proposed. Summary of the invention:

[0005] In view of the problems existing in the prior art, the main purpose of the present invention is to provide a new polymer-based solar photothermal material and its preparation method. The material can be recycled and reused, and the recycling method is simple and fast, and can be applied to seawater desalination.

[0006] In order to achieve the above object, the present invention provides a method for preparing a recyclable polymer-based solar photothermal material, comprising the following steps:

[0007] (1) preparing a porous sodium chloride salt template;

[0008] (2) preparing a polymer precursor mixed solution or prepolymer solution containing exchangeable dynamic bonds and a light-to-heat conversion agent;

[0009] (3) pouring the polymer precursor mixed solution or prepolymer solution prepared in step (2) into the porous sodium chloride salt template prepared in step (1);

[0010] (4) heating the system obtained in step (3) to complete the cross-linking polymerization reaction;

[0011] (5) The cross-linked polymerization reaction system obtained in step (4) is immersed in water to remove the sodium chloride salt template.

[0012] Preferably or optionally, the size of the sodium chloride particles used in preparing the porous sodium chloride salt template in step (1) is 1-200 μm.

[0013] Preferably or optionally, the exchangeable dynamic bond described in step (2) is any one of a disulfide exchangeable dynamic bond, an imine exchangeable dynamic bond, an alkyl exchangeable dynamic bond, an olefin metathesis dynamic bond, an amino exchangeable dynamic bond, a dynamic borate bond, and a siloxane exchangeable dynamic bond.

[0014] Preferably or optionally, the light-to-heat conversion agent added in step (2) is an organic light-to-heat conversion agent and / or an inorganic light-to-heat conversion agent.

[0015] Preferably or optionally, the organic light-to-heat conversion agent is one or more of aniline oligomer, polyaniline, and polypyrrole.

[0016] Preferably or optionally, the inorganic light-to-heat conversion agent is one or more of carbon nanotubes, graphene, carbon black, MXene, silver nanoparticles, gold nanoparticles, and aluminum oxide nanoparticles.

[0017] Preferably or optionally, the light-to-heat conversion agent is added in an amount of 0.1-50% of the mass of the final product.

[0018] On the other hand, the present invention provides a polymer-based solar photo-thermal material, which is prepared using the above-mentioned preparation method.

[0019] In a third aspect, the present invention further provides the use of the above-mentioned polymer-based solar photo-thermal material in a solar photo-thermal interface water evaporator.

[0020] The present invention provides a new polymer-based solar photothermal material and a preparation method thereof. The polymer material has a wide range of sources and flexible material design. The photothermal conversion agent can be flexibly selected and can be an organic photothermal conversion agent or an inorganic photothermal conversion nanomaterial. The pore-forming method adopts a porous sodium chloride template method, which is low-cost and pollution-free. The introduction of exchangeable dynamic covalent bonds gives the cross-linked polymer recyclable properties, realizes resource recycling, and is energy-saving and environmentally friendly. Description of the drawings:

[0021] Figure 1 Schematic diagram of the preparation mechanism and exchange mechanism of the light-heat conversion epoxy polymer material prepared in Example 1;

[0022] Figure 2 This is a scanning electron microscope photograph of the light-heat conversion epoxy polymer material prepared in Example 1;

[0023] Figure 3 is the absorption curve of the light-heat conversion epoxy polymer material prepared in Example 1 within the solar spectrum;

[0024] Figure 4 The temperature variation curve of the light-heat conversion epoxy polymer material prepared in Example 1 at different positions of the material foam over time in Effect Example 3 is shown;

[0025] Figure 5 This is a curve showing the change in water evaporation over time of the light-heat conversion epoxy polymer material prepared in Example 1 in Effect Example 3;

[0026] Figure 6 Schematic diagram of the experiment for recycling the light-heat conversion epoxy polymer material prepared in Example 1 in Effect Example 4;

[0027] Figure 7 This is a comparison chart of the thermal and mechanical properties of the film before and after recycling in Effect Example 4. Specific implementation method:

[0028] In order to enable those skilled in the art to more clearly understand the application, the application will be described in detail below in conjunction with Examples and accompanying drawings. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to ordinary meanings and dictionary meanings, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the application on the basis of the principle of allowing the inventor to appropriately define terms for best interpretation. Therefore, the description proposed here is only for the preferred embodiment for illustration purposes, is not intended to limit the scope of the application, thus it should be understood that, without departing from the spirit and scope of the application, other equivalents or improved methods can be obtained therefrom, and the scope claimed for protection of the application should be based on the scope limited by the claims. Unless otherwise stated, the reagents and instruments used in the following examples are commercially available products.

[0029] Example 1

[0030] An embodiment of the present invention provides a polymer-based solar photo-thermal material.

[0031] The polymer-based solar photothermal material is prepared according to the following method.

[0032] (1) Preparation of sodium chloride salt template: Sodium chloride particles were ground and sieved with a 150-mesh stainless steel sieve to obtain sodium chloride particles with a size less than 150 mesh. The sieved particles were filled into a polytetrafluoroethylene tank with a size of 40 × 40 × 4.5 mm, compacted, and placed in a 93% humidity environment (the environment is a sealed container containing a saturated sodium sulfate aqueous solution) for 4 h to allow the boundaries of the sodium chloride particles to fuse, thereby obtaining a sodium chloride salt template.

[0033] (2) Preparation of prepolymer solution: 0.129 g of amino-terminated aniline trimer (ACAT), 0.390 g of 4,4'-dithiodiphenylamine, 0.990 g of polyetheramine T400, 0.340 g of 2,2-bis(4-epoxypropoxyphenyl)propane and 0.333 g of carbon nanotubes (previously dispersed in DMF) were added to a round-bottom flask in sequence, 8 mL of DMF was added, the mixture was stirred thoroughly, and the mixture was placed in an oil bath at 80°C and stirred for 6 min for pre-crosslinking to obtain a prepolymer solution.

[0034] In this step, the preparation method of ACAT used is as follows:

[0035] 5.947 g of 4,4'-diphenylamine sulfate and 73 g of sodium chloride were added sequentially to 600 mL of 1 mol / L hydrochloric acid solution. The mixture was cooled to -10°C in a low-temperature constant-temperature reaction bath. 1.863 g of aniline was added with vigorous stirring. 3.651 g of ammonium persulfate was dissolved in 60 mL of 1 mol / L hydrochloric acid solution and added dropwise to the reaction mixture via a dropping funnel. The reaction was maintained at -10°C for 3 hours. After completion of the reaction, the mixture was filtered and washed with 1 mol / L hydrochloric acid solution and acetone. The precipitate was transferred to 100 mL of 10% ammonia solution and stirred overnight. The mixture was filtered and washed with distilled water until the pH was neutral. The mixture was dried in a vacuum oven at 50°C overnight to obtain a dark purple solid, the ACAT product.

[0036] (3) Pouring: pouring the prepolymer solution obtained in step (2) into the sodium chloride salt template prepared in step (1) while it is still hot.

[0037] (4) Cross-linking: The system obtained in step (3) was placed on a hot plate for cross-linking and curing (80°C for 1 h, 120°C for 2 h).

[0038] (5) Demolding: After cross-linking and curing, the system is immersed in water to remove the sodium chloride salt template to obtain a polymer-based solar photothermal material product.

[0039] The preparation mechanism and exchange mechanism of the polymer-based solar photothermal material prepared in this embodiment are as follows: Figure 1 shown.

[0040] Effect Example 1

[0041] The product obtained in Example 1 was placed under a scanning electron microscope. Figure 2 shown.

[0042] Depend on Figure 2 It can be seen that the polymer-based solar photothermal material prepared in Example 1 has a uniform open-pore structure and can provide a continuous water transmission channel.

[0043] Effect Example 2

[0044] The light absorption performance was tested by UV-visible spectrophotometer to obtain the UV-visible absorption spectrum of the material. Figure 3 shown.

[0045] Depend on Figure 3 It can be seen that the polymer-based solar photo-thermal material prepared in Example 1 has good light absorption performance in the solar spectrum range (250-2500nm).

[0046] Effect Example 3

[0047] The product prepared in Example 1 was placed on the water surface and exposed to sunlight of one intensity. The surface temperature of the material and the temperature of the bottom water layer were measured. The results are shown in Figure 4.

[0048] The evaporation rate and evaporation efficiency of the material were measured at the same time. The results are as follows: Figure 5 shown.

[0049] Depend on Figure 4 and 5 It can be seen that the polymer-based solar photothermal material prepared in Example 1 has excellent light-to-heat conversion performance and thermal insulation performance, as well as good evaporation rate and evaporation efficiency. According to calculations, the evaporation rate of the polymer-based solar photothermal material prepared in Example 1 can reach 1.35 kg m -2 h -1 , the corresponding evaporation efficiency is 89.15%.

[0050] Effect Example 4

[0051] like Figure 6 As shown, the product obtained in Example 1 was subjected to hot pressing (160°C, 10 MPa, 4 h) to obtain a polymer film, and its relevant performance data was measured. After the measurement was completed, the film was cut into pieces and subjected to hot pressing (160°C, 10 MPa, 4 h) to obtain a polymer film again, and the relevant performance data was measured again. The relevant performance data before and after recycling are shown in FIG. Figure 7 shown.

[0052] Depend on Figure 7It can be seen that the film obtained after recycling can still be recycled by hot pressing to obtain a complete polymer film after being cut into pieces. Compared with the film before recycling, the mechanical and thermal properties of the recycled film are basically unchanged, indicating that the polymer-based solar photo-thermal material prepared in Example 1 has excellent recycling performance.

[0053] The present invention provides a new polymer-based solar photothermal material and a preparation method thereof. The polymer material has a wide range of sources and flexible material design. The photothermal conversion agent can be flexibly selected and can be an organic photothermal conversion agent or an inorganic photothermal conversion nanomaterial. The pore-forming method adopts a porous sodium chloride template method, which is low-cost and pollution-free. The introduction of exchangeable dynamic covalent bonds gives the cross-linked polymer recyclable properties, realizes resource recycling, and is energy-saving and environmentally friendly.

[0054] The above-mentioned specific embodiments of the present application are merely preferred embodiments for explaining the present application, and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications without creative contribution as needed. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for preparing a recyclable polymer-based solar thermal material, characterized in that: The following steps are involved: (1) preparing a porous sodium chloride salt template; (2) stirring and reacting amino-terminated aniline trimer, 4,4'-dithiodiphenylamine, polyetheramine T400, 2,2-bis(4-epoxypropoxyphenyl)propane, and carbon nanotubes to perform pre-crosslinking to prepare a polymer precursor prepolymer solution containing exchangeable dynamic bonds and a light-to-heat conversion agent; (3) pouring the polymer precursor prepolymer solution prepared in step (2) into the porous sodium chloride salt template prepared in step (1); (4) heating the system obtained in step (3) to complete the cross-linking polymerization reaction; (5) The cross-linked polymerization reaction system obtained in step (4) is immersed in water to remove the sodium chloride salt template.

2. The preparation method according to claim 1, characterized in that The size of the sodium chloride particles used in preparing the porous sodium chloride salt template in step (1) is 1-200 μm.

3. The preparation method according to any one of claims 1 or 2, characterized in that The amount of the light-heat conversion agent added is 0.1-50% of the mass of the final product.

4. A polymer-based solar photothermal material, characterized in that: The material is prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the polymer-based solar photo-thermal material according to claim 4 in a solar photo-thermal interface water evaporator.

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