Low-density and high-specific-surface-area block-shaped polydivinylbenzene foam material and preparation thereof

Abstract

The invention provides a block-shaped polydivinylbenzene foam material with low density and high specific surface area and preparation of the block-shaped polydivinylbenzene foam material. The polydivinylbenzene block foam material has an ultrahigh specific surface area, a rich pore structure and good hydrophobicity. According to the preparation method, a brand new solvent system is adopted, a mixed solution of tetrahydrofuran and ethylene glycol serves as a reaction solvent, polydivinylbenzene of a block structure can be obtained, and the prepared polydivinylbenzene foam material has the advantages of being high in specific surface area, high in thermal decomposition temperature and the like; wide application prospects are realized in the field of physical adsorption. The preparation method is relatively simple and convenient, the block-shaped polydivinylbenzene foam material with low density and high specific surface area can be prepared by only one step, and the yield can be greatly improved.

Description

Technical Field

[0001] The invention relates to a low-density, high-specific-surface-area block-shaped polydivinylbenzene foam material and a preparation method and application thereof, belonging to the technical field of functional materials. Background Art

[0002] At present, most foam materials are thermoplastic resins, but these thermoplastic resins are not resistant to high temperatures and soften at high temperatures, which limits their application and development. In order to solve the above problems, the researchers further studied the performance and advantages of thermosetting resins and prepared microspherical polydivinylbenzene foam materials.

[0003] Polydivinylbenzene has the characteristics of high cross-linking degree, high temperature resistance, super hydrophobicity, etc. It will not soften at high temperatures, which greatly expands the use temperature range of foam materials. At present, polydivinylbenzene microspheres have been widely used in separation engineering, drug carriers, adsorption, chromatography, catalysis and other fields. However, the average particle size of existing polydivinylbenzene microspheres is about 1-4μm, and the specific surface area is about 200-810m 2 / g, pore size is about 2-4nm, due to the small particle size of polydivinylbenzene microspheres, it is not easy to recycle, and it also increases the complexity of the preparation process. At the same time, in actual use, polydivinylbenzene microspheres also have problems such as difficult collection, serious dust, and impact on human health, which greatly limits the application of polydivinylbenzene. Summary of the invention

[0004] In order to improve the deficiencies of the prior art, the present invention provides a low-density, high-specific-surface-area block-shaped polydivinylbenzene foam material and a preparation method and use thereof. The polydivinylbenzene foam material prepared by the present invention has a block-shaped structure and also has the characteristics of low density and high specific surface area, which can effectively avoid the occurrence of the above-mentioned problems and greatly expand the application of polydivinylbenzene microspheres.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for preparing a blocky polydivinylbenzene foam material, the method comprising the following steps:

[0007] 1) mixing divinylbenzene, an initiator, tetrahydrofuran and optionally added ethylene glycol to obtain a mixed solution;

[0008] 2) subjecting the mixed solution of step 1) to a solvothermal reaction to prepare a gel-like polydivinylbenzene;

[0009] 3) soaking the gel-like polydivinylbenzene obtained in step 2) in anhydrous ethanol and deionized water in sequence to prepare a polydivinylbenzene hydrogel;

[0010] 4) placing the polydivinylbenzene hydrogel in step 3) in liquid nitrogen for rapid freezing, and after the polydivinylbenzene hydrogel is completely frozen, transferring it to a vacuum freeze dryer for vacuum freeze drying to obtain the block-shaped polydivinylbenzene foam material.

[0011] According to an embodiment of the present invention, in step 1), divinylbenzene and an initiator are respectively dissolved in a mixed solvent of tetrahydrofuran and ethylene glycol to obtain a mixed solution. Preferably, the initiator is first dissolved in a mixed solvent of tetrahydrofuran and ethylene glycol, and then divinylbenzene is added to obtain a mixed solution.

[0012] According to an embodiment of the present invention, in step 1), the volume ratio of ethylene glycol to tetrahydrofuran is 0-30:100, for example, 0:100, 3:100, 5:100, 8:100, 10:100, 12:100, 15:100, 18:100, 20:100, 25:100, 28:100 or 30:100.

[0013] According to an embodiment of the present invention, in step 1), the mass ratio of the initiator to divinylbenzene is 1-5:100, for example, 1:100, 2:100, 3:100, 4:100 or 5:100.

[0014] According to an embodiment of the present invention, in step 1), the initiator is selected from at least one of azobisisobutyronitrile, di-tert-butyl peroxide, dibenzoyl peroxide, diisopropylbenzene peroxide, tert-butyl hydroperoxide, potassium persulfate, and ammonium persulfate.

[0015] According to an embodiment of the present invention, in step 1), the mass volume ratio of divinylbenzene to tetrahydrofuran is 1-3g:20-30ml, such as 1g:20ml, 1g:25ml, 1g:30ml, 2g:20ml, 2g:25ml, 2g:30ml, 3g:20ml, 3g:25ml or 3g:30ml.

[0016] According to an embodiment of the present invention, in step 1), the mixing is performed at room temperature.

[0017] According to an embodiment of the present invention, in step 1), the mixing is performed under stirring conditions.

[0018] According to an embodiment of the present invention, in step 1), in the mixed solution, divinylbenzene and the initiator can be completely dissolved in the mixed solvent system of tetrahydrofuran and ethylene glycol.

[0019] According to the embodiments of the present invention, it is found that the type of solvent system has a great influence on the dispersion state and specific surface area of ​​the prepared polydivinylbenzene. The inventors of the present application unexpectedly found that when a new solvent system (a mixed solvent system of tetrahydrofuran and ethylene glycol) is used, a low-density, high-specific surface area, block-shaped polydivinylbenzene foam material can be prepared, and the specific surface area can reach 800-1300m 2 / g, the density is 0.05-0.1g / cm 3 When other solvent systems are used, the low-density, high-specific-surface-area, block-shaped polydivinylbenzene foam material of the present application cannot be obtained.

[0020] According to an embodiment of the present invention, in step 2), the temperature of the solvothermal reaction is 120-200°C, such as 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C.

[0021] According to an embodiment of the present invention, in step 2), the solvent thermal reaction time is 8-24 hours, such as 8 hours, 9 hours, 10 hours, 12 hours, 15 hours, 16 hours, 18 hours, 20 hours or 24 hours.

[0022] According to an embodiment of the present invention, in step 2), the mixed solution of step 1) is transferred to a hydrothermal reactor, and the hydrothermal reactor is placed in an oven and kept at 120-200° C. for 8-24 hours, and then taken out to obtain gel-like polydivinylbenzene.

[0023] According to an embodiment of the present invention, in step 2), the gel-like polydivinylbenzene is in block form, and the size and shape of the block-like gel-like polydivinylbenzene can be adjusted by adjusting the size and shape of the hydrothermal reactor. The shape of the hydrothermal reactor conventionally used in the art is a cylindrical structure, so the obtained gel-like polydivinylbenzene also has a cylindrical structure.

[0024] According to an embodiment of the present invention, in step 3), the gel-like polydivinylbenzene contains unreacted divinylbenzene, unreacted initiator, tetrahydrofuran and ethylene glycol. By immersing the gel-like polydivinylbenzene in anhydrous ethanol and deionized water in sequence, the unreacted divinylbenzene, unreacted initiator, tetrahydrofuran and ethylene glycol in the gel-like polydivinylbenzene can be completely replaced with deionized water to obtain a polydivinylbenzene hydrogel.

[0025] According to an embodiment of the present invention, in step 3), the gel-like polydivinylbenzene of step 2) is first immersed in anhydrous ethanol, and the process is repeated multiple times (e.g., 2-3 times) until the unreacted divinylbenzene, unreacted initiator, tetrahydrofuran and ethylene glycol in the gel-like polydivinylbenzene are all replaced by anhydrous ethanol, and then the gel-like polydivinylbenzene of step 2) is immersed in deionized water, and the process is repeated multiple times (e.g., 2-3 times) until the anhydrous ethanol in the gel-like polydivinylbenzene is all replaced by deionized water, thereby preparing a polydivinylbenzene hydrogel.

[0026] According to an embodiment of the present invention, in step 3), during the soaking process, the gel-like polydivinylbenzene can still maintain its block structure without becoming loose or deformed.

[0027] According to an embodiment of the present invention, in step 4), it is found that the drying method will affect the aggregation state of the final product. Conventional oven drying will cause the polymer foam to shrink and crack, and the pore structure will collapse, which will lead to a decrease in specific surface area. When liquid nitrogen is used to freeze the polydivinylbenzene hydrogel, and then combined with a vacuum freeze-drying method, the water in the polydivinylbenzene hydrogel can be directly sublimated from the ice crystal state to water vapor, which can maintain the shape of polydivinylbenzene while avoiding the collapse of the pore structure, further increasing the specific surface area of ​​the polydivinylbenzene foam material, and obtaining a low-density, high-specific surface area, block-shaped polydivinylbenzene foam material.

[0028] According to an embodiment of the present invention, in step 4), the polydivinylbenzene hydrogel of step 3) is immersed in liquid nitrogen, so as to ensure that the polydivinylbenzene hydrogel is quickly frozen and uniformly frozen.

[0029] According to an embodiment of the present invention, in step 4), the complete freezing means that all the water in the polydivinylbenzene hydrogel is frozen into ice. Under normal operating conditions, the polydivinylbenzene hydrogel in step 3) can be completely frozen by placing it in liquid nitrogen for more than 5-10 minutes.

[0030] According to an embodiment of the present invention, in step 4), the vacuum degree of the vacuum freeze-drying is 5-20 Pa, and the time of the vacuum freeze-drying is 24-48 h.

[0031] According to an embodiment of the present invention, the specific surface area of ​​the block-shaped polydivinylbenzene foam material is 800-1300m 2 / g.

[0032] According to an embodiment of the present invention, the density of the polydivinylbenzene foam material is 0.05-0.1 g / cm 3In the present invention, unless otherwise specified, the density of the polydivinylbenzene foam material refers to the apparent density of the bulk polydivinylbenzene foam material.

[0033] According to an embodiment of the present invention, the polydivinylbenzene foam material has a block-like structure, and the size of the block-like structure is not particularly limited, and can be adjusted according to the size of the selected hydrothermal reactor. When the size of the selected hydrothermal reactor is larger, a large-sized block can be obtained; when the size of the selected hydrothermal reactor is smaller, a small-sized block can be obtained.

[0034] The present invention also provides a block-shaped polydivinylbenzene foam material, and the block-shaped polydivinylbenzene foam material is prepared by the above method.

[0035] According to an embodiment of the present invention, the specific surface area of ​​the block-shaped polydivinylbenzene foam material is 800-1300m 2 / g.

[0036] According to an embodiment of the present invention, the density of the block-shaped polydivinylbenzene foam material is 0.05-0.1 g / cm 3 .

[0037] The invention also provides a use of a block-shaped polydivinylbenzene foam material, which is used in the field of physical adsorption.

[0038] Beneficial effects:

[0039] The present invention provides a low-density, high-specific-surface-area block-shaped polydivinylbenzene foam material and its preparation. The polydivinylbenzene block-shaped foam material has an ultra-high specific surface area, rich pore structure, and good hydrophobicity. The preparation method adopts a brand-new solvent system, using a mixed solution of tetrahydrofuran and ethylene glycol as a reaction solvent, which can not only obtain polydivinylbenzene with a block-shaped structure, but also the prepared polydivinylbenzene foam material has the advantages of high specific surface area, high thermal decomposition temperature, etc., and has broad application prospects in the field of physical adsorption. The preparation method is relatively simple, and only one step is required to prepare a low-density, high-specific-surface-area block-shaped polydivinylbenzene foam material, which can greatly improve the yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 are scanning electron microscope images of bulk polydivinylbenzene prepared in Examples 1-3 at different magnifications, wherein Figure 1 a and d in the above are the bulk polydivinylbenzene of Example 1, Figure 1 b and e in the above are the bulk polydivinylbenzene of Example 2, Figure 1 c and f in the figure are bulk polydivinylbenzene of Example 3.

[0041] Figure 2 This is the thermogravimetric analysis diagram of the bulk polydivinylbenzene prepared in Example 1.

[0042] Figure 3 This is a physical picture of the block-like polydivinylbenzene prepared in Example 1. DETAILED DESCRIPTION

[0043] The preparation method of the present invention will be described in further detail below in conjunction with specific examples. It should be understood that the following examples are only exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0044] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0045] Example 1

[0046] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in a mixed solution of 25ml tetrahydrofuran (THF) and 5ml ethylene glycol, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180℃, the hydrothermal reactor was transferred to the oven, and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a cylindrical polydivinylbenzene gel. The polydivinylbenzene gel was soaked in anhydrous ethanol and deionized water three times respectively to remove the residual monomers and initiators, and the solvent was completely replaced to obtain a polydivinylbenzene hydrogel. The polydivinylbenzene hydrogel was then placed in liquid nitrogen for rapid freezing, and then transferred to a vacuum freeze dryer with a vacuum degree of 20Pa and a drying time of 48h. After the sample was completely dried, it was taken out to obtain a block-shaped polydivinylbenzene foam material.

[0047] The test results show that the BET specific surface area of ​​the prepared bulk polydivinylbenzene foam material is 1209 m 2 / g, apparent density is 0.1g / cm 3 The dimensions are 2.5cm in bottom diameter and 4cm in height.

[0048] The prepared bulk polydivinylbenzene foam material was subjected to a carbon dioxide adsorption test. The test results showed that under the conditions of 298K and 1 bar, the carbon dioxide adsorption capacity of the bulk polydivinylbenzene foam material of Example 1 was 12.9 cm 3 / g.

[0049] Example 2

[0050] The other operations are the same as those in Example 1, except that the feed is as follows: 0.02 g of azobisisobutyronitrile (AIBN) is dissolved in a mixed solution of 27 ml of tetrahydrofuran (THF) and 3 ml of ethylene glycol, and then 2 g of divinylbenzene is added to the mixed solution.

[0051] The test results show that the BET specific surface area of ​​the prepared block-like polydivinylbenzene foam material is 897m 2 / g, apparent density is 0.1g / cm 3 The dimensions are 2.5cm in bottom diameter and 4cm in height.

[0052] Example 3

[0053] The other operations are the same as those in Example 1, except that the feed is as follows: 0.02 g of azobisisobutyronitrile (AIBN) is dissolved in a mixed solution of 23 ml of tetrahydrofuran (THF) and 7 ml of ethylene glycol, and then 2 g of divinylbenzene is added to the mixed solution.

[0054] The test results show that the BET specific surface area of ​​the prepared bulk polydivinylbenzene foam material is 972 m 2 / g, apparent density is 0.1g / cm 3 The dimensions are 2.5cm in bottom diameter and 4cm in height.

[0055] Example 4

[0056] The other operations were the same as those in Example 1, except that the feed was as follows: 0.02 g of azobisisobutyronitrile (AIBN) was dissolved in 30 ml of tetrahydrofuran (THF), and then 2 g of divinylbenzene was added to the mixed solution.

[0057] The test results show that the BET specific surface area of ​​the prepared bulk polydivinylbenzene foam material is 800m 2 / g, apparent density is 0.1g / cm 3 The dimensions are 2.5cm in bottom diameter and 4cm in height.

[0058] Example 5

[0059] The other operations were the same as those in Example 1, except that the feed was as follows: 0.02 g of azobisisobutyronitrile (AIBN) was dissolved in 25 ml of tetrahydrofuran (THF) and 5 ml of ethylene glycol, and then 1 g of divinylbenzene was added to the mixed solution.

[0060] The test results show that the BET specific surface area of ​​the prepared block-like polydivinylbenzene foam material is 948m 2 / g, apparent density is 0.05g / cm 3 The dimensions are 2.5cm in bottom diameter and 4cm in height.

[0061] Comparative Example 1

[0062] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in a mixed solution of 15ml tetrahydrofuran (THF) and 15ml ethylene glycol, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel with no fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0063] Comparative Example 2

[0064] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in a mixed solution of 20ml tetrahydrofuran (THF) and 10ml ethylene glycol, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel with no fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0065] Comparative Example 3

[0066] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in a mixed solution of 30ml of ethylene glycol, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel without a fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0067] Comparative Example 4

[0068] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in 25ml of tetrahydrofuran (THF) and 5ml of ethylene glycol, and then 0.5g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel without a fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0069] Comparative Example 5

[0070] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in 30ml of acetic acid, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 180°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel with no fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0071] Comparative Example 6

[0072] First, 0.02g of azobisisobutyronitrile (AIBN) was dissolved in a mixed solution of 25ml tetrahydrofuran (THF) and 5ml ethylene glycol, and then 2g of divinylbenzene was added to the mixed solution. After AIBN and divinylbenzene were completely dissolved, the mixed solution was transferred to a 50ml polytetrafluoroethylene liner, and the liner was placed in a hydrothermal reactor and tightened. The oven temperature was set to 100°C, and the hydrothermal reactor was transferred to the oven and kept warm for 16 hours. After the reactor cooled to room temperature, the reactor was taken out of the oven to obtain a polydivinylbenzene gel with no fixed shape. The gel was in a loose state, similar to a solution, and its shape changed after being poured into a container.

[0073] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a blocky polydivinylbenzene foam material, wherein: The method comprises the following steps: 1) mixing divinylbenzene, an initiator, tetrahydrofuran and optionally added ethylene glycol to obtain a mixed solution; 2) subjecting the mixed solution of step 1) to a solvothermal reaction to prepare a gel-like polydivinylbenzene; 3) soaking the gel-like polydivinylbenzene obtained in step 2) in anhydrous ethanol and deionized water in sequence to prepare a polydivinylbenzene hydrogel; 4) placing the polydivinylbenzene hydrogel in step 3) in liquid nitrogen for rapid freezing, and after the polydivinylbenzene hydrogel is completely frozen, transferring it to a vacuum freeze dryer for vacuum freeze drying to obtain the block-shaped polydivinylbenzene foam material.

2. The method for preparing a blocky polydivinylbenzene foam material according to claim 1, wherein: In step 1), the volume ratio of ethylene glycol to tetrahydrofuran is 0-30:100; And / or, in step 1), the mass ratio of the initiator to divinylbenzene is 1-5:

100.

3. The method for preparing a blocky polydivinylbenzene foam material according to claim 1 or 2, wherein: In step 1), the mass volume ratio of divinylbenzene to tetrahydrofuran is 1-3g:20-30ml.

4. The method for preparing a blocky polydivinylbenzene foam material according to any one of claims 1 to 3, wherein: In step 2), the temperature of the solvent thermal reaction is 120-200° C.; and the solvent thermal reaction time is 8-24 hours.

5. The method for preparing a blocky polydivinylbenzene foam material according to any one of claims 1 to 4, wherein: In step 2), the gel-like polydivinylbenzene is in block form.

6. The method for preparing a blocky polydivinylbenzene foam material according to any one of claims 1 to 5, wherein: In step 3), the gel-like polydivinylbenzene of step 2) is first immersed in anhydrous ethanol, and the process is repeated for multiple times until the unreacted divinylbenzene, unreacted initiator, tetrahydrofuran and ethylene glycol in the gel-like polydivinylbenzene are all replaced by anhydrous ethanol, and then the gel-like polydivinylbenzene of step 2) is immersed in deionized water, and the process is repeated for multiple times until the anhydrous ethanol in the gel-like polydivinylbenzene is all replaced by deionized water, thereby preparing a polydivinylbenzene hydrogel.

7. The method for preparing a blocky polydivinylbenzene foam material according to any one of claims 1 to 6, wherein: In step 4), the vacuum degree of the vacuum freeze drying is 5-20 Pa, and the time of the vacuum freeze drying is 24-48 hours.

8. A block-shaped polydivinylbenzene foam material, wherein: The blocky polydivinylbenzene foam material is prepared by the method according to any one of claims 1 to 7.

9. The blocky polydivinylbenzene foam material according to claim 8, wherein: The specific surface area of ​​the blocky polydivinylbenzene foam material is 800-1300m 2 / g; And / or, the density of the block-shaped polydivinylbenzene foam material is 0.05-0.1 g / cm 3 .

10. Use of the blocky polydivinylbenzene foam material according to claim 8 or 9 in the field of physical adsorption.

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