A porous polymer foam containing aniline trimer and preparation and use thereof

Abstract

The application belongs to the field of seawater desalination materials, and particularly relates to a polymer containing aniline trimer, which is obtained by polymerization of aniline trimer, polyethylene glycol and aliphatic diisocyanate, has a porous foam form, has water wettability and good photo-thermal conversion performance, and can be used as a seawater desalination material. The application also relates to a preparation method and application of the polymer, and the preparation method comprises polymerization of aniline trimer and polyethylene glycol in an organic solvent. The preparation method is simple, and process parameters are easy to control.

Description

Technical Field

[0001] This invention belongs to the field of seawater desalination materials, specifically relating to a porous polymer foam containing aniline trimer and its preparation and application. Background Technology

[0002] Freshwater resources are a strategic global issue, and water is one of the most abundant compounds on Earth. 71% of the Earth's surface is covered by water, but seawater is undrinkable due to its high salinity. Therefore, there is an urgent need for large-scale, high-efficiency seawater desalination technology to provide sufficient freshwater resources.

[0003] Traditional seawater desalination technologies include multi-stage flash evaporation (MSF), multi-effect evaporation (MED), and reverse osmosis (RO). These technologies are difficult to implement in off-grid or remote areas due to their high energy consumption, expensive equipment, and difficult installation. Solar-driven interfacial water evaporation strategies, however, offer a new approach to effective seawater desalination, using solar energy as the sole energy source and being environmentally friendly.

[0004] Because water has poor light absorption and significant heat loss, it is necessary to design photothermal materials to achieve an efficient conversion process from light to water vapor through interfacial heating. This evaporation system can achieve a high absorptivity of the solar spectrum and reduce heat loss from water to the environment, thereby improving evaporation efficiency. Solar-driven seawater desalination technology mainly includes an interfacial system, in which photothermal materials float at the water-air interface, directly absorb sunlight and convert it into heat energy, directly heating the water surface and reducing heat exchange between the water and the environment, thereby improving evaporation efficiency. Materials used for solar-driven interfacial water evaporation need to meet the following conditions: (1) high solar light absorption capacity; (2) high solar light-to-heat conversion capacity; (3) low thermal conductivity and specific heat capacity; (4) density less than water; (5) open structure penetrating the upper and lower surfaces of the material. However, most existing interfacial photothermal materials are multi-component systems, consisting of a water-absorbing layer, a heat-insulating layer, and an evaporation layer. Their preparation process is complex, production costs are high, and large-area preparation is difficult, making it difficult to achieve industrial applications. Meanwhile, current single-component photothermal materials cannot simultaneously meet the above conditions, resulting in low evaporation efficiency. Therefore, it is necessary to design a new type of single-component photothermal material. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the purpose of this invention is to provide a porous polymer foam material containing aniline trimer and a method for preparing the same. The preparation process is simple, energy-efficient, and low-cost.

[0006] This invention first provides a polymer obtained by polymerizing aniline trimer with polyethylene glycol, wherein the aniline trimer has the following structure:

[0007]

[0008] The polymer as described above, wherein the molar ratio of aniline trimer to polyethylene glycol is 1-10:10-1, preferably 1-5:5-1, and more preferably 1:1.

[0009] The polymers described above, wherein the polyethylene glycol is polyethylene glycol with a molecular weight of 400-6000, preferably PEG-400, PEG-600, PEG-800, PEG-1000, or PEG-2000.

[0010] The polymer described above has the following structure:

[0011]

[0012] Where n = 8 - 136, m = 20 - 500;

[0013] Preferably, n = 10-45, m = 100-300;

[0014] More preferably, n = 13, m = 200.

[0015] The polymer described above is in the form of a porous polymer foam.

[0016] The present invention also provides a method for preparing the polymer as described above, comprising the following steps:

[0017] In the presence of dibutyltin dilaurate, aniline trimer, polyethylene glycol, and aliphatic diisocyanate are dissolved in an organic solvent and reacted in a template.

[0018] Preferably, the reaction is followed by curing, cooling, demolding, and the resulting material is then cleaned and dried.

[0019] As described above in the preparation method, the organic solvent is preferably one of N-methylpyrrolidone, N,N-dimethylformamide, and tetrahydrofuran; preferably N-methylpyrrolidone.

[0020] The aliphatic diisocyanate is preferably hexamethylene diisocyanate.

[0021] As described above, preferably, the molar ratio of the aniline trimer to polyethylene glycol is 1-10:10-1, more preferably 1-5:5-1, and even more preferably 1:1; the molar ratio of the aliphatic diisocyanate to the aniline trimer is 1-12:1, preferably 3-6:1, and even more preferably 6:1.

[0022] As described above, preferably, the mass fraction of the dibutyltin dilaurate is 0.5-1%.

[0023] As described above, preferably, the curing is performed according to the following procedure:

[0024] The reaction temperature is 50-70℃, preferably 70℃; the reaction time is 20-24h, preferably 24h.

[0025] The reaction temperature is increased from 50℃-70℃ to 170-200℃ at a rate of 1-4℃ / min, preferably 2℃ / min, and preferably to 170℃; the reaction time is 0.5-3h, preferably 1h.

[0026] The reaction temperature is 170-200℃, preferably 200℃; the reaction time is 2-3h, preferably 2h.

[0027] As described above, the template is a sodium chloride salt template.

[0028] Preferably, the sodium chloride particles in the sodium chloride salt template are smaller than 100 μm.

[0029] More preferably, the sodium chloride salt template is a sodium chloride salt template prepared according to a known method, such as drying sodium chloride particles and repeatedly grinding them to obtain sodium chloride particles with a size of less than 100 μm, spreading them evenly in a polytetrafluoroethylene tank and compacting them. Preferably, sodium chloride particles with a size of less than 100 μm are obtained by passing them through a 150-mesh stainless steel sieve.

[0030] Preferably, the polytetrafluoroethylene (PTFE) tank has dimensions of 10mm × 10mm × 2mm.

[0031] As described above, the cleaning of the obtained material involves washing the material in deionized water; preferably, the cleaning is supplemented by ultrasound, and the cleaning is performed multiple times, preferably three times.

[0032] The present invention also provides the application of the polymer as described above in desalination of seawater, wherein the polymer is used as a seawater desalination material, and more specifically as an interfacial solar-powered seawater desalination material.

[0033] Compared with the prior art, the porous polymer provided by the present invention has the following beneficial effects:

[0034] 1. The raw materials for preparing the porous polymer of the present invention are abundant, and various types of polyethylene glycol can be used. The preparation is simple and inexpensive.

[0035] 2. The preparation method of the porous polymer of the present invention is simple and the process parameters are easy to control;

[0036] 3. The porous polymer of this invention is in foam form and has a certain degree of hydrophilicity, allowing it to be wetted by water:

[0037] 4. The porous polymer foam of the present invention can be reused after ultrasonic cleaning in deionized water;

[0038] 5. The porous polymer foam of the present invention is a single component with a simple structure. Attached Figure Description

[0039] Figure 1 The porous foam morphology microstructure of the polymer prepared in Example 1 of this invention is shown under a cold field emission scanning electron microscope.

[0040] Figure 2 The infrared spectrum of the polymer obtained in Example 1 of this invention;

[0041] Figure 3 The contact angle of the polymer prepared in Example 1 of the present invention varies with time.

[0042] Figure 4 This is a comparative study on the effect of the polymer prepared in Example 1 of the present invention on the concentration of sodium, potassium, calcium and magnesium ions when used for ion desalination.

[0043] Figure 5 This is a comparison of the effects of the polymer prepared in Example 1 of the present invention on the concentration of copper, gallium, and zinc ions when used for ion desalination. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the aniline-based polymer and its preparation method of this invention are further described in detail below through examples. It should be understood that the specific examples described herein are only for explaining this invention and are not intended to limit this invention.

[0045] This invention provides a polymer containing aniline trimer and a method for preparing the same. The polymer is obtained by polymerizing aniline trimer with polyethylene glycol, has a porous foam morphology, and exhibits good hydrophilicity and photothermal conversion properties.

[0046] Example 1: Preparation of interfacial solar-powered seawater desalination material containing aniline trimer

[0047] (1) Preparation of sodium chloride salt template

[0048] Sodium chloride granules were dried and repeatedly ground, and sodium chloride granules with a size of less than 100 μm were obtained using a 150-mesh stainless steel sieve. These granules were then spread evenly in a 10 mm × 10 mm × 2 mm polytetrafluoroethylene (PTFE) trough and compacted.

[0049] (2) Preparation of porous polymer foam containing aniline trimer structure

[0050] Aniline trimer monomer and polyethylene glycol 600 were added at a molar ratio of 1:1, specifically 1 mmol of each monomer (aniline trimer) and polyethylene glycol were added to 4 ml of N-methylpyrrolidone. Hexamethylene diisocyanate was then added to achieve a molar ratio of 6:1 between hexamethylene diisocyanate and aniline trimer monomer. After thorough mixing, 1% wt of dibutyltin dilaurate was added. The solution was stirred for 10–20 seconds and then poured into a sodium chloride template until the template was completely filled. Curing was then performed according to the following procedure: curing at 70℃ for 24 hours, curing at 70℃–170℃ for 1 hour, and curing at 170℃ for 2 hours. After cooling, the material was demolded and ultrasonically cleaned three times in deionized water. After drying, a porous polymer containing an aniline trimer structure was obtained.

[0051] The obtained porous polymer is in foam form, and its microstructure under cold field emission scanning electron microscopy is as follows: Figure 1 As shown.

[0052] Example 2: Preparation of interfacial solar-powered seawater desalination material containing aniline trimer

[0053] (1) Preparation of sodium chloride salt template

[0054] Sodium chloride granules were dried and repeatedly ground, and sodium chloride granules with a size of less than 100 μm were obtained using a 150-mesh stainless steel sieve. These granules were then spread evenly in a 10 mm × 10 mm × 2 mm polytetrafluoroethylene (PTFE) trough and compacted.

[0055] (2) Preparation of porous polymer foam containing aniline trimer structure

[0056] Aniline trimer monomer and polyethylene glycol-400 were added to 8 ml of N-methylpyrrolidone at a molar ratio of 1:4 (1 mmol of aniline trimer monomer and 4 mmol of polyethylene glycol-400). Hexamethylene diisocyanate was then added to bring the molar ratio of hexamethylene diisocyanate to aniline trimer monomer to 10:1. After thorough mixing, 1% wt of dibutyltin dilaurate was added. The solution was stirred for 10–20 seconds and then poured into a sodium chloride template until the template was completely filled. Curing was then performed according to the following procedure: curing at 70℃ for 24 hours, curing at 70℃-170℃ for 1 hour, and curing at 170℃ for 2 hours. After cooling, the material was demolded and ultrasonically cleaned three times in deionized water. After drying, a porous polymer foam containing an aniline trimer structure was obtained.

[0057] Example 3: Preparation of interfacial solar-powered seawater desalination material containing aniline trimer

[0058] (1) Preparation of sodium chloride salt template

[0059] Sodium chloride granules were dried and repeatedly ground, and sodium chloride granules with a size of less than 100 μm were obtained using a 150-mesh stainless steel sieve. These granules were then spread evenly in a 10 mm × 10 mm × 2 mm polytetrafluoroethylene (PTFE) trough and compacted.

[0060] (2) Preparation of porous polymer foam containing aniline trimer structure

[0061] Aniline trimer monomer and polyethylene glycol-1000 were added at a molar ratio of 1:2 (1 mmol of aniline trimer monomer and 2 mmol of polyethylene glycol-1000) to 4 ml of N-methylpyrrolidone. Hexamethylene diisocyanate was then added to achieve a molar ratio of 8:1 between hexamethylene diisocyanate and aniline trimer monomer. After thorough mixing, 1% wt of dibutyltin dilaurate was added. The solution was stirred for 10–20 seconds and then poured into a sodium chloride template until the template was completely filled. Curing was then performed according to the following procedure: curing at 60℃ for 24 hours, curing at 60℃–170℃ for 2 hours, and curing at 170℃ for 3 hours. After cooling, the material was demolded, ultrasonically cleaned three times in deionized water, and dried to obtain a porous polymer foam containing an aniline trimer structure.

[0062] Example 4: Preparation of interfacial solar-powered seawater desalination material containing aniline trimer

[0063] (1) Preparation of sodium chloride salt template

[0064] Sodium chloride granules were dried and repeatedly ground, and sodium chloride granules with a size of less than 100 μm were obtained using a 150-mesh stainless steel sieve. These granules were then spread evenly in a 10 mm × 10 mm × 2 mm polytetrafluoroethylene (PTFE) trough and compacted.

[0065] (2) Preparation of porous polymer foam containing aniline trimer structure

[0066] Aniline trimer monomer and polyethylene glycol-2000 were added at a molar ratio of 1:3 (1 mmol of aniline trimer monomer and 3 mmol of polyethylene glycol-2000) to 8 ml of N-methylpyrrolidone. Hexamethylene diisocyanate was then added to bring the molar ratio of hexamethylene diisocyanate to aniline trimer monomer to 12:1. After thorough mixing, 1% wt of dibutyltin dilaurate was added. The solution was stirred for 10–20 seconds and then poured into a sodium chloride template until the template was completely filled. Curing was then performed according to the following procedure: curing at 70℃ for 24 hours, curing at 70℃–200℃ for 2 hours, and curing at 170℃ for 3 hours. After cooling, the material was demolded, ultrasonically cleaned three times in deionized water, and dried to obtain a porous polymer foam containing an aniline trimer structure.

[0067] Example 5: Structural and performance characterization of interfacial solar-powered seawater desalination materials

[0068] Taking the interfacial solar desalination material prepared in Example 1 as an example, structural characterization and hydrophilicity performance testing were carried out.

[0069] (1) Structural characterization

[0070] The structure was characterized using infrared spectroscopy to determine the functional groups in the polymer, and the results are as follows: Figure 2 As shown in the figure, the solid line represents aniline trimer (ACAT), and the dashed line represents the polymer obtained by reacting aniline trimer with polyethylene glycol 6000. New characteristic peaks such as OH, -CH2-, C=O, arC=C, and COC are visible in the figure.

[0071] (2) Hydrophilicity test

[0072] The hydrophilicity of polymer foams is characterized using a contact angle test. Water droplets are applied to the surface of the polymer foam, and the change in contact angle over time is recorded. Figure 3 As shown, when a drop of water is placed on the surface of a polymer foam, the polymer foam is completely wetted after 14 minutes.

[0073] Example 6: Evaporation effect of interfacial solar seawater desalination material

[0074] The polymer prepared in Example 1 was used as an exemplary interfacial solar desalination material, and its evaporation effect was tested.

[0075] Method: A 10*10*30mm cuvette was used as the evaporation container and placed in a polystyrene insulated chamber for evaporation testing. The insulated chamber was placed inside an electronic balance, and the cuvette was filled with deionized water at room temperature. Then, the interfacial solar desalination material prepared in Example 1 was placed at the top of the liquid surface. After the simulated light source stabilized, the center of the simulated light source spot was adjusted to the position of the cuvette opening. A VISI solar standard was connected to a multimeter to intensify the sunlight intensity at the height of the cuvette opening to 1 kW / m². 2 The water loss was measured in situ using a balance and computer software. Mass data was read every minute, and each evaporation test lasted for one hour. The true evaporation rate was the evaporation rate under the given conditions minus the evaporation rate under the dark chamber conditions.

[0076] Evaporation rate: The polymer prepared in Example 1, used as an interfacial solar desalination material, exhibits an evaporation rate of 3.8-4.5 kg·m³ under one day of sunlight. -2 ·h -1 .

[0077] Desalination effect: After evaporation treatment with the interfacial solar seawater desalination material prepared in Example 1, a 3.5 wt% sodium chloride solution, a 1 wt% sodium-potassium-calcium-magnesium ion mixed solution, and a 1 wt% heavy metal ion (copper, gallium, zinc) solution were prepared, the concentrations of each ion were within the range of the WHO-specified drinking water quality standards. The changes in ion concentration are shown in the figure below. Figure 4 , Figure 5 As shown, solid bars represent ion concentrations before material treatment, while dashed bars represent ion concentrations after material treatment. It is evident that the polymer prepared in this application can effectively reduce the concentrations of sodium, potassium, calcium, and magnesium ions, as well as copper, gallium, and zinc ions, at different concentrations, thereby achieving seawater desalination.

[0078] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. The present invention can also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A polymer, characterized in that, The polymer is obtained by polymerization of aniline trimer, polyethylene glycol and aliphatic diisocyanate, the aliphatic diisocyanate is hexamethylene diisocyanate, and the aniline trimer has the following structure: ， The molar ratio of the aniline trimer to polyethylene glycol is 1-5:5-1, and the molar ratio of the aliphatic diisocyanate to the aniline trimer is 1-12:

1. The polyethylene glycol has a molecular weight of 400-6000. The structure of the polymer is shown as follows: Wherein, n=8-136, m=20-500.

2. The polymer of claim 1, further characterized by, The n=10-45, m=100-300.

3. The polymer of claim 1, further characterized by, The n=13, m=200.

4. The polymer of any one of claims 1-3, further characterized by, The polymer is a porous foam.

5. Process for the preparation of the polymer according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: The aniline trimer, polyethylene glycol and aliphatic diisocyanate are dissolved in an organic solvent in the presence of dibutyltin dilaurate, and the reaction is carried out in a mold; After the reaction, the obtained material is cleaned, dried, solidified, cooled and demolded; The organic solvent is one of N-methylpyrrolidone, N,N-dimethylformamide and tetrahydrofuran; The aliphatic diisocyanate is hexamethylene diisocyanate.

6. The method of claim 5, further characterized by: The molar ratio of the aniline trimer to polyethylene glycol is 1-10:10-1.

7. The method of claim 5, further characterized by: The solidification is carried out according to the following procedure: The reaction temperature is 50-70 ℃, and the reaction time is 20-24 h; The reaction temperature is increased from 50-70 ℃ to 170-200 ℃ at a rate of 1-4 ℃ / min, and the reaction time is 0.5-3 h; The reaction temperature is 170-200 ℃, and the reaction time is 2-3 h.

8. The method of claim 5, further characterized by, The mold is a sodium chloride salt mold.

9. Use of the polymer of any one of claims 1-4 as a seawater desalination material.

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