An ultralow-density ultrahigh-porosity sPS aerogel and a preparation method and application thereof

Abstract

The application belongs to the technical field of aerogels, and specifically discloses a super-low-density and super-high-porosity sPS aerogel as well as a preparation method and application thereof. The preparation method of the syndiotactic polystyrene aerogel comprises the following steps: adding syndiotactic polystyrene into p-xylene, heating, and obtaining a syndiotactic polystyrene solution; transferring the syndiotactic polystyrene solution into a mold, cooling at room temperature, and forming a syndiotactic polystyrene gel; and freeze-drying the syndiotactic polystyrene gel to obtain the product. In the application, p-xylene is used as a solvent to dissolve sPS, and the high melting point characteristic of p-xylene is utilized to freeze and sublimate the sPS in the middle, so that the sPS aerogel is obtained, solvent evaporation is avoided, and the structure of the aerogel is maintained. Meanwhile, the preparation process does not require any solvent exchange, is simple in steps, saves a large amount of solvent generated in the solvent exchange process, and avoids the adverse effects on the fragile sPS gel in the solvent exchange process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerogels, and particularly relates to an ultra-low-density and ultra-high-porosity sPS (syndiotactic polystyrene) aerogel and a preparation method and application thereof. BACKGROUND

[0002] An aerogel is a three-dimensional continuous porous material composed of nanoholes and nanoframes, and is prepared by replacing solvents in a gel network with air in a proper manner, but the process of replacing solvents with air should not damage the original gel network, so as to generate nanoholes and preserve nanoframes. The aerogel is difficult to be prepared by normal pressure drying, because in the process of solvent evaporation, the gel will collapse due to strong capillary pressure generated by solvent evaporation, the original gel network is damaged, and the expected structure cannot be formed.

[0003] sPS is a semi-crystalline engineering thermoplastic polymer, which has been proved to be able to form a thermoreversible sPS gel using various solvents. Guerra and his colleagues first prepared an sPS aerogel using supercritical carbon dioxide (scCO2) drying technology. In order to ensure that the aerogel has almost no shrinkage or collapse, multiple solvent exchanges should be carried out between the solvent and liquid CO2. After the solvent is completely removed, the pressure is reduced, so that the liquid CO2 returns to the gaseous state and is replaced by air, and thus the initial network structure of the gel will not change. The highest porosity of the sPS aerogel prepared by scCO2 drying is 98.5%. Gowd et al. first prepared an sPS aerogel by freeze-drying technology. They carried out systematic solvent exchange on the sPS gel with different concentrations of ethanol-water mixture, then carried out solvent exchange with water to obtain a hydrogel, and finally freeze-dried the hydrogel to obtain an sPS aerogel. The highest porosity of the sPS aerogel prepared by freeze-drying the sPS hydrogel is 97.0%.

[0004] At present, whether the sPS aerogel is prepared by scCO2 drying or freeze-drying, multiple solvent exchanges are involved to completely wash away the solvent and avoid solvent evaporation, so as to maintain the structure of the aerogel. The solvent exchange step is not only cumbersome, but also can cause the gel to break and shrink during processing, which seriously increases the difficulty of obtaining an ultra-low-density (<10 mg / cm 3 ) and ultra-high-porosity (>99%) sPS aerogel. So far, there is no report on an ultra-low-density and ultra-high-porosity sPS aerogel. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a super-low-density and super-high-porosity sPS aerogel and a preparation method and application thereof. The sPS aerogel has super-low density and super-high porosity, excellent dielectric properties and adsorption properties, and is suitable for preparing an insulating layer in a microelectronic device and an adsorbent in sewage treatment.

[0006] The inventive concept of the present application is that the present application uses p-xylene as a solvent to dissolve sPS. The high melting point (13℃) of p-xylene allows it to be frozen in a freeze dryer, so that sPS aerogel can be obtained directly by sublimation, avoiding the adverse effects caused by solvent evaporation. At the same time, the sPS aerogel of the present application only needs to go through sPS dissolution, gelation and freeze drying when prepared, without any solvent exchange, so that high-quality super-low-density and super-high-porosity sPS aerogel can be obtained, eliminating the damage of the solvent exchange process to the fragile gel. Therefore, the sPS aerogel prepared by the present application not only has super-low dielectric constant and suitable mechanical properties, and extremely weak polarization ability under the action of an electric field, but can be used to manufacture an insulating layer in a microelectronic device to reduce the capacitive effect in the circuit; and has high hydrophobicity and oleophilicity, and excellent adsorption capacity for oil / organic solvents, and can be applied to sewage treatment to rapidly separate oil stains and oil-containing substances in sewage, thereby reducing the pollution of harmful substances to the environment.

[0007] To solve the above technical problems, the first aspect of the present application provides a preparation method of syndiotactic polystyrene aerogel, comprising the following steps:

[0008] (1) Preparation of a stock solution: adding syndiotactic polystyrene in p-xylene and heating to obtain a syndiotactic polystyrene solution;

[0009] (2) Preparation of a gel: transferring the syndiotactic polystyrene solution to a mold and cooling at room temperature to form a syndiotactic polystyrene gel;

[0010] (3) Preparation of an aerogel: freeze-drying the syndiotactic polystyrene gel to obtain the syndiotactic polystyrene aerogel.

[0011] Preferably, in step (1), the molecular weight of the syndiotactic polystyrene is 300000-400000 g / mol.

[0012] Preferably, in step (1), the concentration of the syndiotactic polystyrene solution is 0.001-0.005 g / mL.

[0013] Preferably, in step (1), the heating temperature is 140-160℃.

[0014] Preferably, in step (1), the heating time is 1-24 hours; further preferably, the heating time is 2-5 hours.

[0015] Preferably, in step (1), the heating mode is oil bath heating.

[0016] Preferably, in step (2), the room temperature cooling time is 1-24 hours; further preferably, the room temperature cooling time is 2-5 hours.

[0017] Preferably, in step (3), the freeze-drying temperature regime is: first freezing at -18℃ to -24℃ for 1-24 hours, and then freezing at -40℃ to -80℃ for 12-120 hours.

[0018] Further preferably, in step (3), the freeze-drying temperature regime is: first freezing at -20℃ to -24℃ for 2-5 hours, and then freezing at -60℃ to -80℃ for 24-60 hours.

[0019] The second aspect of the present application provides a syndiotactic polystyrene aerogel prepared by the above preparation method, wherein the porosity of the syndiotactic polystyrene aerogel is >99%.

[0020] Preferably, the porosity of the syndiotactic polystyrene aerogel is 99.4-99.6%.

[0021] Preferably, the density of the syndiotactic polystyrene aerogel is <10 mg / cm 3 ; further preferably, the density of the syndiotactic polystyrene aerogel is 4.5-5.8 mg / cm 3 .

[0022] The third aspect of the present application provides the use of the above syndiotactic polystyrene aerogel.

[0023] Preferably, the use is a microelectronic device, wherein the microelectronic device comprises an insulating layer, and the insulating layer contains the above syndiotactic polystyrene aerogel.

[0024] The sPS aerogel prepared by the present application has ultra-low dielectric constant and suitable mechanical properties, and has very weak polarization ability under the action of electric field, and is suitable for preparing an insulating layer in a microelectronic device to reduce the capacitive effect in the circuit.

[0025] Preferably, the use is an adsorbent, wherein the adsorbent comprises the above syndiotactic polystyrene aerogel.

[0026] The sPS aerogel prepared by this invention has high hydrophobicity and oleophilicity and excellent oil / organic solvent adsorption properties, making it suitable for wastewater treatment. It can quickly separate oil and oily substances from wastewater, thereby reducing the pollution of the environment by harmful substances.

[0027] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0028] (1) In the preparation of the sPS aerogel of the present invention, sPS is dissolved in p-xylene as a solvent. Utilizing its high melting point, p-xylene allows for direct sublimation during freeze-drying to obtain the sPS aerogel, avoiding solvent evaporation and preserving the aerogel structure. Furthermore, the preparation process only requires sPS dissolution, gelation, and freeze-drying, without any solvent exchange. This simplifies the process, saves on the large amount of solvent generated during solvent exchange, and avoids the adverse effects of solvent exchange on the fragile sPS gel. The sPS aerogel obtained by the present invention has a density <10 mg / cm³. 3 It can even reach 4.5-5.8 mg / cm³. 3 Porosity >99%, and can even reach 99.4-99.6%.

[0029] (2) The sPS aerogel prepared by this invention not only has an ultra-low dielectric constant and suitable mechanical properties, making it suitable for preparing insulating layers in microelectronic devices to reduce the capacitance effect in circuits; but also has high hydrophobicity and oleophilicity, and has excellent adsorption capacity for oil / organic solvents, making it suitable for sewage treatment, rapidly separating oil and oily substances in sewage, thereby reducing the pollution of harmful substances to the environment, and has good market application value. Attached Figure Description

[0030] Figure 1 High-temperature gel permeation chromatography, high-temperature carbon NMR spectroscopy, and differential scanning calorimetry of the sPS powder used in the various embodiments and comparative examples of the present invention.

[0031] Figure 2 Electron photographs of the sPS aerogels prepared in Examples 1-4;

[0032] Figure 3 The dielectric constant diagram, compressive stress-strain curve diagram, and diagram of the sPS aerogel prepared in Examples 3-4 at 0.01-100 kHz are shown.

[0033] Figure 4 The images show the contact angle, water adhesion, surface state of water and oil droplets, and adsorption capacity of oil / organic solvents for the sPS aerogels prepared in Examples 3-4. Detailed Implementation

[0034] The present application will be described in detail below with reference to examples, so as to facilitate the understanding of the present application by those skilled in the art. It is necessary to point out here that the examples are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Non-essential improvements and adjustments of the present application made by those skilled in the art according to the above description of the present application shall still fall within the scope of protection of the present application. Meanwhile, the raw materials mentioned below which are not described in detail are all commercially available products; the process steps or preparation methods which are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0035] Figure 1 The high-temperature gel permeation chromatography (GPC) (a, the abscissa represents the molecular weight, and the ordinate represents the dispersity index, PDI), high-temperature nuclear magnetic carbon spectrum (b, the abscissa represents the chemical shift, and the ordinate represents the intensity) and differential scanning calorimetric graph (c, the abscissa represents the temperature, and the ordinate represents the heat flow) of the sPS powder used in each example and comparative example of the present application are shown in the following figures. Figure 1 a, wherein M w represents the molecular weight, and PDI represents the dispersity index), high-temperature nuclear magnetic carbon spectrum (b, the abscissa represents the chemical shift, and the ordinate represents the intensity) and differential scanning calorimetric graph (c, the abscissa represents the temperature, and the ordinate represents the heat flow) of the sPS powder used in each example and comparative example of the present application are shown in the following figures. Figure 1 b, the abscissa represents the chemical shift, and the ordinate represents the intensity) and differential scanning calorimetric graph (c, the abscissa represents the temperature, and the ordinate represents the heat flow) of the sPS powder used in each example and comparative example of the present application are shown in the following figures. Figure 1 c, the abscissa represents the temperature, and the ordinate represents the heat flow) and differential scanning calorimetric graph (c, the abscissa represents the temperature, and the ordinate represents the heat flow) of the sPS powder used in each example and comparative example of the present application are shown in the following figures. Figure 1 It can be seen from the above figures that the sPS powder has a high syndiotacticity and melting point.

[0036] Example 1

[0037] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0038] (1) Preparation of a stock solution: 0.02 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150℃ for heating, and the sPS was dissolved under magnetic stirring for 2 hours to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.001 g / mL.

[0039] (2) Preparation of a gel: the sPS p-xylene solution prepared in step (1) was transferred to a mold and cooled, and the gel was formed after standing at room temperature for 2 hours, thereby obtaining a sPS p-xylene gel.

[0040] (3) Preparation of an aerogel: the sPS p-xylene gel prepared in step (2) was frozen in a refrigerator at -20℃ for 2 hours, and then was placed in a freeze dryer at -80℃ for freeze drying for 24 hours, thereby obtaining the sPS aerogel of the present example, which is denoted as sPS 0.001 .

[0041] Example 2

[0042] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0043] (1) Preparation of the stock solution: 0.04 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C and heated, and dissolved for 3 hours under magnetic stirring to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.002 g / mL.

[0044] (2) Preparation of the gel: The sPS p-xylene solution prepared in step (1) was transferred to a mold and cooled, and gelled at room temperature for 3 hours to obtain an sPS p-xylene gel.

[0045] (3) Preparation of the aerogel: The sPS p-xylene gel prepared in step (2) was frozen in a refrigerator at -20°C for 3 hours, and then placed in a freeze dryer at -80°C for 36 hours to obtain the sPS aerogel of the present example, denoted as sPS 0.002 .

[0046] Example 3

[0047] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0048] (1) Preparation of the stock solution: 0.06 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C and heated, and dissolved for 4 hours under magnetic stirring to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.003 g / mL.

[0049] (2) Preparation of the gel: The sPS p-xylene solution prepared in step (1) was transferred to a mold and cooled, and gelled at room temperature for 4 hours to obtain an sPS p-xylene gel.

[0050] (3) Preparation of the aerogel: The sPS p-xylene gel prepared in step (2) was frozen in a refrigerator at -20°C for 4 hours, and then placed in a freeze dryer at -80°C for 48 hours to obtain the sPS aerogel of the present example, denoted as sPS 0.003 .

[0051] Example 4

[0052] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0053] (1) Preparation of the stock solution: 0.10 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C and heated, and dissolved under magnetic stirring for 5 hours to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.005 g / mL.

[0054] (2) Preparation of the gel: The sPS p-xylene solution prepared in step (1) was transferred to a mold and cooled, and gelled at room temperature for 5 hours to obtain an sPS p-xylene gel.

[0055] (3) Preparation of the aerogel: The sPS p-xylene gel prepared in step (2) was frozen in a refrigerator at -20°C for 5 hours, and then placed in a freeze dryer at -80°C for freeze drying for 60 hours to obtain the sPS aerogel of the example, denoted as sPS 0.005 .

[0056] Comparative Example 1

[0057] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0058] (1) Preparation of the stock solution: 0.06 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C and heated, and dissolved under magnetic stirring for 5 hours to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.005 g / mL.

[0059] (2) Preparation of the gel: The sPS p-xylene solution prepared in step (1) was transferred to a mold and cooled, and gelled at room temperature for 5 hours to obtain an sPS p-xylene gel.

[0060] (3) Preparation of the aerogel: The sPS p-xylene gel prepared in step (2) was frozen in a refrigerator at -20°C for 5 hours, and then placed in a freeze dryer at -80°C for freeze drying for 60 hours to obtain the sPS aerogel of the example, denoted as sPS 0.003 -TOL.

[0061] Comparative Example 2

[0062] A preparation method of a syndiotactic polystyrene aerogel, comprising the following steps:

[0063] (1) Preparation of the stock solution: 0.06 g of sPS powder with a molecular weight of 350000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C and heated, and dissolved under magnetic stirring for 5 hours to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.005 g / mL.

[0064] (2) Gel preparation: The sPS p-xylene solution prepared in step (1) was transferred into a mold and cooled to prepare a gel, and the gel was left to stand at room temperature for 4 hours to prepare an sPS p-xylene gel.

[0065] (3) Aerogel preparation: The sPS p-xylene gel prepared in step (2) was subjected to solvent exchange with ethanol, and then subjected to solvent exchange with ethanol / water mixtures with volume fractions of 75:25, 50:50 and 25:75, respectively, and finally subjected to solvent exchange with water, which took 3 days to obtain an sPS hydrogel; the sPS hydrogel was then frozen in a refrigerator at -20°C for 4 hours, and then placed in a freeze dryer at -80°C for freeze drying for 48 hours to obtain the sPS aerogel of the present comparative example, which is denoted as sPS 0.003 -Water.

[0066] Comparative Example 3

[0067] A method for preparing a syndiotactic polystyrene aerogel, comprising the following steps:

[0068] (1) Preparation of a stock solution: 0.06 g of sPS powder with a molecular weight of 350,000 g / mol was added to a pressure-resistant bottle containing 20 mL of p-xylene, the pressure-resistant bottle was placed in an oil bath at 150°C, and the sPS was dissolved under magnetic stirring for 4 hours to form a uniform sPS p-xylene solution, and the concentration of sPS was 0.003 g / mL.

[0069] (2) Gel preparation: The sPS p-xylene solution prepared in step (1) was transferred into a mold and cooled to prepare a gel, and the gel was left to stand at room temperature for 4 hours to prepare an sPS p-xylene gel.

[0070] (3) Aerogel preparation: The sPS p-xylene gel prepared in step (2) was subjected to solvent exchange with liquid CO2 multiple times, and the specific process was as follows: the sPS p-xylene gel was placed in a chamber filled with liquid CO2 for 10 hours to exchange p-xylene with liquid CO2, then the solvent was discharged, and the chamber was refilled with fresh liquid CO2 for soaking and washing; the same process was repeated five times; after 2 days, heating was performed at 45°C and 11 MPa (31°C and 7.4 MPa higher than the supercritical point of CO2), and after 2 hours, CO2 was discharged under reduced pressure under supercritical conditions; an sPS aerogel was obtained, which is denoted as sPS 0.003 -scCO2.

[0071] Performance test

[0072] 1. Density and porosity

[0073] Density and porosity of sPS aerogels prepared in Examples 1-4 were tested. Among them: the density of aerogel is mass volume density; porosity is calculated by the difference between the density of sPS aerogel (1.056 g / cm3) and the skeleton density of sPS powder (1.056 g / cm3) and the percentage of skeleton density. The test results are shown in Table 1. 3 ) and the density of aerogel. The test results are shown in Table 1.

[0074] Table 1:

[0075] sPS aerogel Density (mg / cm 3 )]]> Porosity (%) Example 1 sPS 0.001 ]] 5.8 99.5 Example 2 sPS 0.002 ]]> 5.7 99.5 Example 3 sPS 0.003 ]]> 4.5 99.6 Example 4 sPS 0.005 ]] 6.6 99.4

[0076] Figure 2 Electronic photos of ultra-low density and ultra-high porosity sPS aerogels prepared in Examples 1-4, wherein: Figure 2 a and Figure 2 b are respectively the real photos and weighing photos of sPS aerogels prepared in Example 4 and Example 3; Figure 2 c is the real photo of sPS p-xylene solution prepared in different concentrations in Examples 1-4; Figure 2 d and Figure 2 e are respectively the real photos and weighing photos of sPS aerogels prepared in Example 2 and Example 1.

[0077] From Figure 2 and Table 1, it can be seen that high-quality ultra-low density and ultra-high porosity sPS aerogels are prepared in Examples 1-4. However, using the preparation method of Comparative Example 1, since the melting point of the solvent toluene (-95℃) is lower than the temperature of the freeze dryer (-80℃), toluene cannot be frozen, and toluene evaporates instead of sublimates from the gel network during freeze drying, resulting in a serious destruction of the structure of the gel by capillary pressure, and high-porosity sPS aerogels cannot be prepared. Using the preparation method of Comparative Example 2, the fragile gel is difficult to be completely taken out of the mold, and further causes the fracture of the gel during the solvent exchange process, and complete high-porosity sPS aerogels cannot be prepared. Using the preparation method of Comparative Example 3, the fragile gel is seriously damaged during the exchange process with liquid CO2 under high pressure, and complete high-porosity sPS aerogels cannot be prepared.

[0078] 2. Dielectric constant and mechanical properties

[0079] The dielectric constant and compressive modulus of the sPS aerogels prepared in Examples 3-4 were tested. Specifically: the dielectric constant was measured using a dielectric analyzer (DEA, DS6000, Triton) at room temperature with a titanium sample holder as electrodes in the frequency range of 0.01-100 kHz. The DEA instrument was calibrated at 1 kHz, and the electrodes were open-circuited and short-circuited to ensure they were always usable (resistance <2Ω). The compressive modulus was tested using a universal testing machine (CTM6203) with a 50N load cell. Multiple cylindrical aerogels with a height-to-diameter ratio of approximately 1.5:1 were compressed at a speed of 1 mm / min. The compressive modulus was calculated from the stress-strain curve within the initial linear range. The test results were the average of three samples for each specimen. The test results are shown in Table 2.

[0080] Table 2:

[0081] sPS aerogel Dielectric constant (1 KHz) Compression modulus (MPa) Example 3 sPS 0.003 ]] 1.010 0.06 Example 4 sPS 0.005 ]]> 1.014 0.24

[0082] Figure 3 Dielectric constant diagrams of the sPS aerogels prepared in Examples 3-4 at 0.01-100 kHz ( Figure 3 a, where the horizontal axis represents frequency and the vertical axis represents dielectric constant; the compressive stress-strain curve of sPS aerogel ( Figure 3 b, (x-axis: Compressive Strain; y-axis: Compressive Stress) and a graph showing SPS aerogel bearing an object 2000 times its own mass. Figure 3 As shown in Table 2, the sPS aerogels prepared in Examples 3-4 have ultra-low dielectric constants and suitable mechanical properties. Specifically, the dielectric constant is close to that of air (1.0), and the polarization ability under the action of an electric field is extremely weak. They can be used to manufacture insulating layers in microelectronic devices to reduce the capacitance effect in circuits.

[0083] 3. Adsorption performance

[0084] Figure 4 The images show the contact angle, water adhesion, surface state of water and oil droplets, and adsorption capacity of oil / organic solvents for the sPS aerogels prepared in Examples 3-4.

[0085] The contact angle test process is as follows: the contact angle is measured by sessile drop method on a Dataphysics OCA 50 instrument equipped with SCA 20 software under ambient conditions, the contact angle value is the average of at least three measurements of a 2 μL drop of ultrapure water at different positions of each sample, and then calculated by an ellipse fitting mode. The water adhesion test process is as follows: a drop of water (2 μL) contacts the sPS aerogel surface under external force, and then separates from the sPS aerogel surface, the whole process is recorded, it can be seen that the water drop is severely deformed under compression, and no obvious adhesion is observed in the separation process, indicating that the ultra-light sPS aerogel has significant anti-adhesion performance to water. The water drop oil drop surface state test process is as follows: a n-hexane drop (stained with oil red O, 15 μL) is dropped on the surface of the aerogel, the drop immediately sinks into the surface and disappears, and a water drop (stained with methylene blue, 4 μL) is repelled on the surface of the aerogel to form a spherical bead. The oil / organic solvent absorption capacity test process is as follows: a sufficient amount of oil / organic solvent is placed in a beaker, and then the sPS aerogel is placed in the beaker, and the absorption is waited to be completed, after the aerogel is taken out, the surface liquid is wiped with filter paper, and weighed, the absorption capacity of the aerogel is calculated as the difference between the mass after absorption and the original mass of the aerogel and the ratio of the original mass of the aerogel.

[0086] Figure 4 a and Figure 4 b are the contact angles of the sPS aerogels prepared in Example 4 and Example 3, respectively, which are 143.7 ± 0.2° and 145.2 ± 0.2°, respectively; Figure 4 c is the water drop oil drop surface state diagram of the sPS aerogel prepared in Example 4 (Water represents water, and n-hexane represents n-hexane); Figure 4 d1- Figure 4 d4 is the water adhesion diagram of the sPS aerogel prepared in Example 4; Figure 4 e is the absorption capacity diagram of the sPS aerogels prepared in Examples 3-4 to oil / organic solvents including n-hexane, chloroform, pump oil, soybean oil and ethanol. From Figure 4 It can be seen that the sPS aerogels prepared in Examples 3-4 have high hydrophobic and oleophilic capacity, and excellent oil / organic solvent absorption capacity, which are suitable for sewage treatment, rapidly separate oil stains and oil-containing substances in sewage, and thus reduce the pollution of harmful substances to the environment.

[0087] For those skilled in the art of the present application, without departing from the concept of the present application, can make several simple deductions or substitutions, without having to go through the creative labor. Therefore, the simple improvements made by the person skilled in the art according to the disclosure of the present application, should be within the scope of protection of the present application. The above examples are the preferred embodiments of the present application, any similar process and equivalent changes made, should belong to the protection scope of the present application.

Claims

1. A method for preparing syndiotactic polystyrene aerogel, characterized in that, Includes the following steps: (1) Preparation of stock solution: Add syndiotactic polystyrene to p-xylene and heat to obtain syndiotactic polystyrene solution; the molecular weight of the syndiotactic polystyrene is 300,000-400,000 g / mol, and the concentration of the syndiotactic polystyrene solution is 0.001-0.005 g / mL; (2) Preparation of gel: The syndiotactic polystyrene solution is transferred into a mold and cooled at room temperature to form a syndiotactic polystyrene gel; (3) Preparation of aerogel: The syndiotactic polystyrene gel is freeze-dried to obtain the syndiotactic polystyrene aerogel; the freeze-drying temperature regime is as follows: first freeze at -18℃ to -24℃ for 1 to 24 hours, and then freeze at -40℃ to -80℃ for 12 to 120 hours. Solvent exchange is not included in the steps described.

2. The method for preparing syndiotactic polystyrene aerogel according to claim 1, characterized in that, In step (1), the heating temperature is 140-160℃; and / or the heating time is 1-24 hours.

3. The method for preparing syndiotactic polystyrene aerogel according to claim 1, characterized in that, In step (2), the time for room temperature cooling is 1-24 hours.

4. A syndiotactic polystyrene aerogel, characterized in that, The syndiotactic polystyrene aerogel prepared by any one of claims 1-3 has a porosity > 99%.

5. The syndiotactic polystyrene aerogel according to claim 4, characterized in that, The density of the syndiotactic polystyrene aerogel is <10 mg / cm³. 3 .

6. A microelectronic device, characterized in that, The microelectronic device includes an insulating layer containing the syndiotactic polystyrene aerogel as described in claim 4 or 5.

7. An adsorbent, characterized in that, The adsorbent comprises the syndiotactic polystyrene aerogel as described in claim 4 or 5.

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