Preparation method of super-crosslinked polymer

Abstract

The invention belongs to the technical field of materials, and relates to a preparation method of a super-crosslinked polymer, which comprises the following steps: volatilizing a monomer and a crosslinking agent to a liquid phase interface by adopting a gas-liquid interface polymerization mode in interface polymerization, and carrying out Friedel-Crafts reaction on the gas-liquid interface to prepare the super-crosslinked polymer. The super-crosslinked polymer is obtained by utilizing a Friedel-Crafts reaction of a monomer and a crosslinking agent on a gas-liquid interface, and the hydrogen bond network density of the super-crosslinked polymer, the accumulation state of polymer chains and the electron doping environment can be regulated and controlled by regulating the reaction temperature and the reaction time, so that the super-crosslinked polymer is obtained. The super-crosslinked polymer can optimize adsorption sites and mass transfer channels aiming at specific metal ions, the adsorption or catalytic performance is improved, the problems that the super-crosslinked polymer prepared through a liquid-liquid interface is poor in orderliness and high in surface roughness are solved, the method has excellent process controllability, special reaction equipment and expensive catalysts are not needed, and the method is suitable for industrial production. The method has the advantages of simple operation process, mild reaction conditions and low production cost.

Description

Technical fields:

[0001] This invention belongs to the field of materials technology and relates to a method for preparing hypercrosslinked polymers, specifically a method for preparing hypercrosslinked polymers using a gas-liquid interface. Background technology:

[0002] Currently, the preparation of porous organic framework membranes using interfacial polymerization strategies has become a research hotspot. Liquid-liquid interfacial polymerization is one of the earliest methods adopted. However, this method has obvious limitations in practical applications: First, the polymerization process is limited by the diffusion kinetics of monomers at the interface. As the membrane forms and thickens, the transmembrane diffusion resistance of monomers increases significantly, causing the polymerization rate to drop rapidly or even stop, making it difficult to obtain a film with uniform and controllable thickness. Second, the difference in microenvironment on both sides of the liquid-liquid interface makes it difficult to control the roughness of the two sides after film formation, often resulting in a rougher surface structure, which affects its performance in precision separation and optoelectronic devices. In addition, this method usually requires a long reaction time to form a continuous film.

[0003] Gas-liquid interfacial polymerization confines the reaction strictly to a two-dimensional interface, effectively overcoming the problem of disordered self-agglomeration of monomers in traditional bulk reactions, thus forming continuous and dense films. Studies have shown that films prepared by gas-liquid interfacial polymerization exhibit excellent flatness and surface roughness (down to 1.5 nm), and the film thickness can be precisely adjusted within the nanometer to micrometer scale. More importantly, this method is simple to operate, operates under mild conditions (usually at room temperature), and is easy to prepare large-area, continuous, defect-free, and mechanically strong self-supporting films, which can greatly improve the processing performance and application potential of porous organic polymer films.

[0004] Chinese Patent 202110685342.1 discloses a method for constructing an oriented gas-liquid interface polymer semiconductor thin film. The method involves dropping a polymer semiconductor solution onto a rectangular gas-liquid interface. The solvent used in the polymer semiconductor solution is immiscible with deionized water and spreads rapidly on the gas-liquid interface. After solvent evaporation, a polymer semiconductor thin film is quickly formed. The film is then transferred from the gas-liquid interface to a substrate. The polymer semiconductor has a rigid main chain framework composed of donors and acceptors. The concentration of the polymer semiconductor solution is 0.1-5 mg / mL, and the solution volume is 2-100 μL. The gas-liquid interface refers to the interface formed between deionized water and air. When deionized water is placed in a container, the surface of the deionized water formed by the deionized water and the container wall is rectangular. This liquid surface, together with the air, constitutes a spatial confinement. A rectangular gas-liquid interface is formed; the aspect ratio of the rectangular gas-liquid interface is greater than or equal to 3 and less than or equal to 100. The polymer semiconductor solution is dropped onto the surface of deionized water, and the solution spreading process is less than 1 second. The solvent evaporation time at room temperature is 30-40 seconds. The film thickness is less than 10 nm. The polymer semiconductor used is a conjugated polymer DPP-TT and DPP-4T with a donor-acceptor conjugated backbone structure. Its acceptor unit is polypyrrolopyrroledione (DPP), and its donor units are thiophene (T) and bis(thiophene) (TT). The solvent used to prepare the polymer semiconductor solution is toluene or chlorobenzene, and the solution concentration is 0.5-3 mg / mL. The substrate material is one of glass, silicon dioxide, polymethyl methacrylate, polystyrene, polydimethylsiloxane, polycarbonate, polyimide, polyethylene terephthalate, or fluorinated polymer CYTOP. It has a fast film formation speed (within 40s), the thickness of the prepared film can be less than 10nm, it has good molecular orientation, and it can be transferred to the surface of a variety of dielectric materials. It can be used to prepare organic field-effect transistors and has broad application prospects in the field of flexible electronics.

[0005] Chinese Patent 201710425489.0 discloses a method for preparing a thin-film composite membrane based on a gas / liquid interface reaction, comprising the following steps: (1) floating a hydrophobic polymer porous base membrane on the surface of a deposition liquid and reacting it at 10-90°C for 0.1-12 hours to form a thin film structure on the polymer porous base membrane at the gas / liquid interface; (2) placing the polymer porous base membrane after the reaction in step (1) in a crosslinking agent solution for crosslinking reaction, and the thin film structure on the polymer porous base membrane crosslinks into a selective functional skin layer to obtain a thin-film composite membrane based on a gas / liquid interface reaction; floating the hydrophobic polymer porous base membrane on the surface of a deposition liquid and reacting it at 40-90°C for 0.1-12 hours to form a thin film structure on the polymer porous base membrane at the gas / liquid interface reaction; The reaction is carried out at 0℃ for 1-2 hours; the concentration of the crosslinking agent solution is 1-10wt%, the crosslinking reaction temperature is 20-80℃, and the crosslinking reaction time is 10-120 minutes; the deposition solution is prepared by dissolving polyphenol monomers and polyamine monomers in phosphate buffer, Tris buffer, carbonate buffer, NaOH solution, KOH solution, or Na2CO3 solution, with the concentrations of polyphenol monomers and polyamine monomers being 1g / L-10g / L. The polyphenol monomers are dopamine and / or o-phenylenediamine, and the polyamine monomers are polyethyleneimine, with the concentrations of polyphenol monomers and polyamine monomers being 2g / L-4g / L, and the mass ratio of polyphenol monomers to polyamine monomers being 1:0.5-1. It has strong controllability, and the prepared thin-layer composite membrane can be applied in nanofiltration, reverse osmosis, forward osmosis, or pervaporation.

[0006] It is evident that utilizing gas-liquid interface polymerization to prepare hypercrosslinked polymers not only improves synthesis efficiency but also reduces preparation costs, is environmentally friendly, and has broad application prospects and significant environmental protection implications. Currently, there is no method for preparing high-performance hypercrosslinked polymers using the gas / liquid interface. Summary of the Invention:

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and to develop a method for preparing hypercrosslinked polymers to prepare hypercrosslinked polymer materials with rich porous structures, controllable structures, and good stability.

[0008] To achieve the above objectives, the hypercrosslinked polymer preparation method of the present invention employs gas-liquid interfacial polymerization, a type of interfacial polymerization. The monomer and crosslinking agent are volatilized to the liquid phase interface, where a Friedel-Crafts reaction occurs at the gas-liquid interface to prepare the hypercrosslinked polymer. The specific process is as follows:

[0009] The steps of the process are as follows:

[0010] First, the crosslinking agent and monomer are dissolved in 1,2-dichloroethane to prepare a mixed solution;

[0011] Then, the mixed solution and a petri dish with concentrated sulfuric acid at the bottom are placed in a sealed container. The monomer and crosslinking agent evaporate to the surface of the concentrated sulfuric acid and undergo a Friedel-Crafts reaction to obtain a hypercrosslinked polymer.

[0012] Finally, wash with ethanol and dry.

[0013] The crosslinking agent is dimethoxymethane;

[0014] The monomers are volatile aromatic ring compounds, including pyrrole, benzene, furan, thiophene, etc., and the amount used is determined by the bottom area of ​​the petri dish, ranging from 1 to 20 μmol / cm². 2 Preferred concentration: 10 μmol / cm 2 ;

[0015] 1,2-Dichloroethane is used as a solvent for both monomers and crosslinking agents, which affects the evaporation time. The amount used depends on the amount of monomer used; 0-10 mL is used for 1 μmol of monomer, preferably 0.1 mL / μmol.

[0016] The molar ratio of monomer to crosslinking agent is 1:2-10, preferably 1:3;

[0017] Concentrated sulfuric acid is used as a catalyst in the Friedel-Crafts reaction; the amount used depends on the bottom area of ​​the petri dish, ranging from 0.1 to 0.3 mL / cm². 2 0.14 mL / cm is preferred. 2 ;

[0018] The Friedel-Crafts reaction is carried out at a temperature of 0-80°C, preferably 25°C, for a duration of 6-48 hours, preferably 36 hours.

[0019] Compared with existing technologies, this invention uses concentrated sulfuric acid as a catalyst and utilizes the Friedel-Crafts reaction of monomers (containing electron-rich aromatic ring compounds) and crosslinking agents at the gas-liquid interface to obtain hypercrosslinked polymers. By adjusting the reaction temperature and reaction time, the hydrogen bond network density, polymer chain stacking state, and electron doping environment of the hypercrosslinked polymer can be controlled, enabling the hypercrosslinked polymer to optimize adsorption sites and mass transfer channels for specific metal ions, thereby improving adsorption or catalytic performance. This solves the problems of poor orderliness and high surface roughness in the preparation of hypercrosslinked polymers using liquid-liquid interfaces. Its principle is scientifically reliable, with excellent process controllability, requiring no special reaction equipment or expensive catalysts, and the operation process is simple, the reaction conditions are mild, and the production cost is low. Attached image description:

[0020] Figure 1 This is a schematic diagram comparing the test results of the pyrrole-based hypercrosslinked polymers prepared in Examples 1 and 2 of the present invention, where the horizontal axis represents wavenumber and the vertical axis represents transmittance. Detailed implementation method:

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1:

[0023] The process of preparing the hypercrosslinked polymer involved in this embodiment is as follows:

[0024] Add 71 μmol of pyrrole and 177.5 μmol of dimethoxymethane to a beaker containing 7.1 mL of 1,2-dichloroethane and mix well.

[0025] Pour 10 mL of concentrated sulfuric acid into a container with a base area of ​​71 cm². 2 In a petri dish, concentrated sulfuric acid is spread to cover the bottom of the dish.

[0026] The beaker and petri dish were placed in a sealed container at 25°C for 36 hours, and the monomer and crosslinking agent underwent a Friedel-Crafts reaction to obtain a pyrrole-based hypercrosslinked polymer.

[0027] The pyrrole-based hypercrosslinked polymer was thoroughly washed with ethanol, and then further purified by Soxhlet extraction with ethanol for 48 hours. It was then dried in a vacuum oven at 60°C for 24 hours.

[0028] Example 2:

[0029] The main process of the preparation method of the hypercrosslinked polymer involved in this embodiment is the same as that in Example 1, except that the temperature of the Friedel-Crafts reaction is 40°C.

[0030] Example 3:

[0031] The main process of the preparation method of the hypercrosslinked polymer involved in this embodiment is the same as that in Example 1, except that pyrrole is replaced with an equimolar amount of benzene.

[0032] Example 4:

[0033] The hypercrosslinked polymer preparation method described in this embodiment can not only stably prepare pyrrole porous membranes containing methylene crosslinking structures, but also effectively control the microstructure packing density of the film by adjusting the reaction temperature. Figure 1 As shown:

[0034] The pyrrole-based hypercrosslinked polymers prepared in Example 1 (25°C) and Example 2 (40°C) both reached a crosslinking density of 1620 cm⁻¹. -1 The presence of a (C=C) vibrational peak nearby confirms the integrity of the polymer backbone structure.

[0035] At 2920cm -1There is a distinct (-CH-) peak at the point. Since the pyrrole monomer contains only unsaturated carbon, it indicates that a methylene (-CH-) group was introduced between the pyrrole rings, and a three-dimensional hypercrosslinked network was successfully constructed.

[0036] The (NH) stretching vibration peak of Example 1 (25℃) is located at 3221 cm⁻¹. -1 This indicates that an intermolecular hydrogen bond network was formed at low temperatures;

[0037] The (NH) stretching vibration peak in Example 2 (40℃) shifted significantly to 3384 cm⁻¹. -1 This indicates that heating disrupts some hydrogen bonds, leaving the polymer chains in a relatively extended and free state.

Claims

1. A method for preparing a hypercrosslinked polymer, characterized in that, Hypercrosslinked polymers were obtained by using concentrated sulfuric acid as a catalyst and by utilizing the Friedel-Crafts reaction of monomers and crosslinking agents at the gas-liquid interface.

2. The method for preparing a hypercrosslinked polymer according to claim 1, characterized in that, By adjusting the reaction temperature and reaction time, the hydrogen bond network density, polymer chain stacking state, and electron doping environment of the hypercrosslinked polymer can be controlled.

3. The method for preparing a hypercrosslinked polymer according to claim 1 or 2, characterized in that, The specific process is as follows: the crosslinking agent and the monomer are dissolved in 1,2-dichloroethane to obtain a mixed solution; The mixed solution and a petri dish filled with concentrated sulfuric acid were placed in a sealed container. The monomer and crosslinking agent evaporated to the surface of the concentrated sulfuric acid and underwent a Friedel-Crafts reaction to obtain a hypercrosslinked polymer.

4. The method for preparing a hypercrosslinked polymer according to claim 3, characterized in that, The crosslinking agent is dimethoxymethane.

5. The method for preparing a hypercrosslinked polymer according to claim 4, characterized in that, The monomers are electron-rich aromatic ring compounds, including pyrrole, benzene, furan, and thiophene. The amount used is determined by the bottom area of ​​the culture dish, ranging from 1 to 20 μmol / cm². 2 .

6. The method for preparing a hypercrosslinked polymer according to claim 5, characterized in that, 1,2-Dichloroethane is used as the solvent for both the monomer and the crosslinking agent. The amount used depends on the amount of monomer used; 0-10 mL is used for 1 μmol of monomer.

7. The method for preparing a hypercrosslinked polymer according to claim 6, characterized in that, The molar ratio of monomer to crosslinking agent is 1:2-10.

8. The method for preparing a hypercrosslinked polymer according to claim 7, characterized in that, Concentrated sulfuric acid is used as a catalyst in the Friedel-Crafts reaction; the amount used depends on the bottom area of ​​the petri dish, ranging from 0.1 to 0.3 mL / cm². 2 .

9. The method for preparing a hypercrosslinked polymer according to claim 8, characterized in that, The Friedel-Crafts reaction is carried out at temperatures ranging from 0 to 80°C for 6 to 48 hours.

10. A method for preparing a hypercrosslinked polymer according to claim 9, characterized in that, The monomer dosage was 10 μmol / cm. 2 ; The amount of 1,2-dichloroethane used is 0.1 mL / μmol; The molar ratio of monomer to crosslinking agent is 1:3; The volume of concentrated sulfuric acid used is 0.14 mL / cm³. 2 ; The Friedel-Crafts reaction was carried out at a temperature of 25°C for 36 hours.

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