Method for initiating anionic polymerization of styrene through electrochemical means and application thereof

Abstract

The invention discloses a method for initiating anionic polymerization of styrene through an electrochemical means and application of the method. The method comprises the following steps: adding tetraalkylammonium salt into a solvent to obtain a solution serving as electrolyte, adding a styrene monomer into the electrolyte, and applying current to initiate polymerization reaction of styrene. According to the present invention, the polystyrene having a narrow molecular weight distribution (about 15,000-50,000) can be synthesized, and the high quality and the stability of the product are ensured. The invention not only overcomes the problems in the prior art, but also provides a new approach and technical means for developing a novel high polymer material. Through elaborately designed experimental conditions and strict parameter control, the method disclosed by the invention realizes efficient anionic electro-initiated polymerization of styrene, promotes scientific and technological progress in related fields, and brings practical benefits to industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of styrene polymerization, and in particular to a method for initiating anionic polymerization of styrene by electrochemical means and application thereof. Background Art

[0002] In the field of polymer chemistry, styrene is an important monomer, and its polymer polystyrene is widely used in plastic products. Traditionally, the polymerization of styrene is usually carried out by free radical polymerization, anionic polymerization or cationic polymerization. These traditional polymerization methods have their own advantages and disadvantages, but the common problem is that it is difficult to accurately control the molecular weight and distribution of the polymer, and side reactions are easily generated during the polymerization process, affecting the purity and performance of the final product.

[0003] Overview of existing technology:

[0004] Free radical polymerization: This is one of the most commonly used ways to polymerize styrene, using peroxides or azo compounds as initiators. However, this polymerization method results in a wide molecular weight distribution and it is difficult to achieve a high degree of control over the polymer structure.

[0005] Anionic polymerization: This method can provide narrower molecular weight distribution and higher molecular weight control, but it usually requires strictly anhydrous and oxygen-free conditions and is very sensitive to impurities, limiting its industrial application.

[0006] Cationic polymerization: Applicable to certain types of monomers, such as isobutylene, but it is uncommon for styrene due to its low reactivity.

[0007] History and Challenges of Electropolymerization

[0008] Early attempts to directly initiate styrene polymerization using electrolysis were not particularly successful (Reference 1). Previous studies have shown that while small amounts of polymerization can be observed in certain electrolyte solutions, the efficiency is low and there is a lack of consistency in the properties of the resulting polymers. In addition, there is speculation that any possible polymerization may be due to side effects caused by metal deposition rather than a true electro-initiated process (Reference 2).

[0009] Reference [1]: Xue, L., et al. (2020). "Electrochemical polymerization of methyl methacrylate using ammonium persulfate as initiator." Journal of Polymer Science, Part A: Polymer Chemistry, 58(8), 672-684.

[0010] Reference [2]: Kang, J., et al. (2021). "Electrochemical polymerization of conjugated polymers under pulsed currents." Synthetic Metals, 273, 116-124. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide a method for initiating anionic polymerization of styrene by electrochemical means and its application in view of the above-mentioned deficiencies in the prior art.

[0012] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: In a first aspect of the present invention, a method for initiating anionic polymerization of styrene by electrochemical means is provided, comprising the following steps:

[0013] A tetraalkylammonium salt is added to a solvent, and the obtained solution is used as an electrolyte. Styrene monomer is added to the electrolyte, and an electric current is applied to induce a polymerization reaction of styrene.

[0014] Preferably, the method comprises the following steps:

[0015] A tetraalkylammonium salt is added to a solvent to form a saturated solution as an electrolyte, styrene monomer is added to the electrolyte, and current is applied to induce a polymerization reaction of styrene.

[0016] Preferably, the tetraalkylammonium salt is at least one selected from tetramethylammonium chloride, tetraethylammonium chloride and tetrapropylammonium chloride.

[0017] Preferably, the solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone.

[0018] Preferably, the reaction temperature is -8°C to 25°C.

[0019] Preferably, the current applied during the reaction is 10-100 mA.

[0020] Preferably, the volume concentration of the styrene monomer added to the electrolyte is 20% to 70%.

[0021] Preferably, the reaction time is 3 to 12 hours.

[0022] Preferably, the tetraalkylammonium salt is dimethylformamide, the solvent is dimethylformamide, the current applied during the reaction is 50 mA, and the volume concentration of the styrene monomer added to the electrolyte is 40%.

[0023] The second aspect of the present invention provides an application of the above method in the preparation of polystyrene.

[0024] In order to overcome the above problems and explore new polymerization pathways, the present invention studies the electropolymerization of styrene in tetramethylammonium salt solution. The research of the present invention shows that under appropriate conditions, efficient and controllable anionic polymerization of styrene can be achieved. Specifically:

[0025] Unique reaction mechanism: Different from the traditional method, the present invention found that polymerization mainly occurs at the cathode and is carried out through an anionic mechanism. This feature allows polymerization to proceed smoothly even in the presence of free radical inhibitors; when methanol is added as a chain terminator, the reaction is completely inhibited.

[0026] Kinetic characteristics: Experimental data show that there is a first-order dependence between the polymerization rate and the monomer concentration and current intensity, which provides a theoretical basis for optimizing the reaction conditions.

[0027] High electrical efficiency and molecular weight: Compared with previous attempts, the present invention achieves significantly higher electrical efficiency and can achieve relatively high molecular weights (about 15,000 to 50,000) while maintaining molecular weight consistency.

[0028] Influence of non-metal deposition: By designing a separated cell experiment, it was verified that the polymerization was not caused by metal deposition, but was directly caused by electrical initiation.

[0029] The beneficial effects of the present invention are:

[0030] The present invention provides a novel and efficient method for electrically initiating anionic polymerization of styrene in a tetramethylammonium salt solution, which has significant advantages over the prior art. The following are the advantages of the present invention over the prior art, and the technical means used by the present invention to achieve these advantages are described one by one.

[0031] 1. Efficient and controllable molecular weight control

[0032] Advantages description:

[0033] Traditional free radical polymerization methods are difficult to achieve precise control of polystyrene molecular weight, resulting in a wide molecular weight distribution of the product, affecting the consistency and repeatability of material properties. In contrast, the present invention is able to synthesize polystyrene with a narrow molecular weight distribution (about 15,000 to 50,000), ensuring the high quality and stability of the product.

[0034] Technical means:

[0035] By selecting the appropriate current intensity (such as 50mA) and monomer concentration (such as 40%), and combining the use of tetramethylammonium salt as an electrolyte, the occurrence of anionic polymerization mechanism can be effectively promoted, thereby achieving a high degree of control over molecular weight. In addition, operating at lower temperature conditions can further increase the molecular weight, providing an additional means of regulation.

[0036] 2. Simplify reaction conditions and reduce process complexity

[0037] Advantages description:

[0038] Traditional anionic polymerization needs to be carried out in a strict water-free and oxygen-free environment, which places extremely high demands on industrial-scale production and operation and increases costs. The present invention does not require such harsh environmental conditions, reducing process complexity and costs.

[0039] Technical means:

[0040] The present invention utilizes the unique properties of electro-initiated polymerization to directly carry out polymerization reaction in a DMF solvent system containing tetramethylammonium salt, thereby avoiding dependence on an anhydrous and oxygen-free environment. At the same time, by optimizing parameters such as current intensity and monomer concentration, the effectiveness and efficiency of the reaction are guaranteed.

[0041] 3. Improve electrical efficiency and save energy

[0042] Advantages description:

[0043] In the early attempts to directly initiate styrene polymerization by electrolysis, it was found that this method either had no obvious effect, or even if a small amount of polymerized product was generated, its output and quality were unstable and lacked industrial practical value. The present invention significantly improves electrical efficiency and reduces energy consumption.

[0044] Technical means:

[0045] Through systematic research on current intensity (10 to 100 mA) and monomer concentration (20% to 70%), the optimal operating conditions (e.g. 50 mA, 40% monomer concentration) were determined. Under these conditions, a higher monomer conversion rate and electrical efficiency can be obtained, thus achieving the goal of energy saving and efficiency improvement.

[0046] 4. Verify and clarify the reaction mechanism and enhance scientific understanding

[0047] Advantages description:

[0048] There has been controversy over whether electro-initiation really promotes polymerization or is just the result of side reactions such as metal deposition. The present invention eliminates the influence of factors such as metal deposition by designing compartmentalized cell experiments and other inhibitor studies, clarifies that electro-initiation is the real driving factor for polymerization, and enhances the understanding of the entire reaction process.

[0049] Technical means:

[0050] A split cell design was used to verify that polymerization only occurred at the cathode, rather than due to metal deposition; and the existence of anionic polymerization mechanism was further confirmed by introducing different types of inhibitors (such as free radical inhibitors and anionic chain terminators). This not only solved the doubts about the mechanism, but also laid the foundation for subsequent research and development.

[0051] 5.Flexibly adjust the molecular weight to adapt to various application scenarios

[0052] Advantages description:

[0053] Different applications may require a molecular weight within a specific range to meet specific physical or chemical requirements. The present invention allows flexible control of the molecular weight of the final polymer by adjusting key parameters such as current intensity and monomer concentration, adapting to a wider range of applications.

[0054] Technical means:

[0055] According to the specific application requirements, the appropriate combination of current intensity and monomer concentration can be selected. For example, when a higher molecular weight is required, the operation can be carried out at a lower temperature or the monomer concentration can be appropriately increased; conversely, a lower molecular weight product can be obtained by changing these parameters.

[0056] In summary, the present invention not only overcomes the problems existing in the prior art, but also provides a new approach and technical means for developing new polymer materials. Through carefully designed experimental conditions and strict parameter control, the present invention realizes efficient anionic electro-initiated polymerization of styrene, promotes scientific and technological progress in related fields, and brings practical benefits to industrial applications. DETAILED DESCRIPTION

[0057] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0058] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0059] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0060] The present invention provides a method for initiating anionic polymerization of styrene by electrochemical means, comprising the following steps:

[0061] A tetraalkylammonium salt is added to a solvent to form a saturated solution as an electrolyte, styrene monomer is added to the electrolyte, and current is applied to induce a polymerization reaction of styrene.

[0062] In a preferred embodiment, the tetraalkylammonium salt is selected from at least one of tetramethylammonium chloride, tetraethylammonium chloride, and tetrapropylammonium chloride. The presence of tetramethylammonium salt is essential for maintaining appropriate ionic strength and promoting anionic polymerization. More preferably, tetramethylammonium chloride is used.

[0063] In a preferred embodiment, the solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone. More preferably, dimethylformamide (DMF) is used as the solvent because it can dissolve various types of monomers and salts and has a high dielectric constant, which helps to stabilize the generated anions.

[0064] In a preferred embodiment, the volume concentration of styrene monomer added to the electrolyte is 20% to 70%. The monomer concentration also has an important influence on the polymerization effect. A higher monomer concentration is conducive to improving electrical efficiency and obtaining a more stable high molecular weight product, but when the monomer concentration exceeds 60%, the solution conductivity will decrease, and the current intensity needs to be appropriately reduced to maintain effective polymerization. The recommended monomer concentration range is 40% to 60%, and the optimal is 50%.

[0065] In a preferred embodiment, the reaction temperature is -8°C to 25°C. Although the present invention is mainly carried out at room temperature, higher molecular weight polymers can be obtained by operating at lower temperatures (such as 0°C or -8°C). If the molecular weight needs to be adjusted, it can be achieved by changing the reaction temperature.

[0066] In a preferred embodiment, the method for initiating anionic polymerization of styrene by electrochemical means is characterized in that the current applied during the reaction is 10 to 100 mA. The current intensity has a significant effect on the polymerization rate. Experiments have shown that as the current increases, the polymerization rate also increases accordingly, but too high or too low a current will reduce the electrical efficiency. Therefore, it is recommended that the current intensity be maintained between 10 and 100 mA, with a preferred value of about 50 mA.

[0067] In a preferred embodiment, the reaction time is 3 to 12 hours.

[0068] In a preferred embodiment, the tetraalkylammonium salt is dimethylformamide, the solvent is dimethylformamide, the current applied during the reaction is 50 mA, and the volume concentration of the styrene monomer added to the electrolyte is 40%.

[0069] In order to further confirm that the polymerization mechanism is anionic polymerization, the present invention introduces different types of inhibitors into the reaction system, including free radical inhibitors (such as tert-butyl catechol and p-benzoquinone) and anionic chain terminators (such as methanol). The results show that the free radical inhibitors have almost no effect on the polymerization rate, while methanol completely inhibits the polymerization reaction, which strongly supports the present invention's view on the anionic polymerization mechanism.

[0070] In order to verify the polymerization mechanism and exclude any possible free radical contribution, the present invention conducted copolymerization experiments using labeled styrene and methyl methacrylate as monomers. The experimental method is:

[0071] Step 1: Build the Electrolytic Cell

[0072] Construct an electrolytic cell with a divider to ensure physical separation between the anode and cathode. This step is to verify that polymerization occurs only at the cathode and is not due to side reactions caused by metal deposition.

[0073] Step 2: Apply Current

[0074] Using a constant DC power supply, different current intensities (10 to 100 mA) are applied to the electrolytic cell at set time intervals. The current intensity is selected based on the optimal range determined experimentally to ensure efficient polymerization without causing unnecessary side reactions.

[0075] Step 3: Monitoring and Sampling

[0076] Small samples are periodically removed from the cathode area throughout the process for subsequent analysis. By determining characteristics such as the polymer content and its molecular weight, the extent and efficiency of the polymerization reaction can be assessed.

[0077] The experimental results confirmed that the initially formed polymer was mainly composed of styrene units, which was consistent with the expected proportion of anionic polymerization, and once again proved that the present invention adopted an anionic polymerization mechanism.

[0078] The present invention also provides an application of the above method in preparing polystyrene.

[0079] The present invention successfully realizes efficient anionic electropolymerization of styrene through carefully designed experimental conditions and strict parameter control. This method not only solves the problems existing in the prior art, but also provides a new approach and technical means for the development of new polymer materials.

[0080] The key technical point of the present invention is that it solves the problems existing in the prior art, especially realizing efficient and controllable anionic electropolymerization of styrene by specific technical means. The present invention at least carries out the following technical research and improvements, and obtains significant beneficial effects:

[0081] 1. Choose tetramethylammonium salt as electrolyte

[0082] Key role:

[0083] Conventional attempts to directly initiate styrene polymerization by electrolysis have not been significantly successful, in part because the electrolytes used were unsuitable or unstable. The present invention selects tetramethylammonium salts (such as tetramethylammonium chloride) as electrolytes, ensuring appropriate ionic strength and promoting the occurrence of anionic polymerization mechanisms.

[0084] Specific technical means:

[0085] - Use tetramethylammonium salt to form a saturated solution to provide sufficient ion concentration.

[0086] -The presence of tetramethylammonium salt stabilizes the generated anions and avoids free radical interference, thus ensuring the smooth progress of anionic polymerization.

[0087] 2. Determine the appropriate current intensity range

[0088] Key role:

[0089] Early electropolymerization methods either had no significant effect, or even if a small amount of polymerized product was generated, its yield and quality were unstable. The present invention systematically studied the effects of different current intensities and found an optimal current range (10 to 100 mA) that can both promote polymerization and maintain high electrical efficiency.

[0090] Specific technical means:

[0091] - The relationship between current intensity and polymerization rate was experimentally verified, and it was found that 50 mA was one of the preferred operating conditions.

[0092] -Within this current range, efficient monomer conversion can be achieved while maintaining a stable molecular weight distribution.

[0093] 3. Optimize Monomer Concentration

[0094] Key role:

[0095] Monomer concentration directly affects the yield and molecular weight of the polymer. Too low or too high monomer concentration will affect the reaction efficiency and the quality of the final product. The present invention finds the best operating range through the study of monomer concentration (20% to 70% by volume) to ensure high yield and ideal molecular weight control.

[0096] Specific technical means:

[0097] -Studies have shown that 40% monomer concentration exhibits optimal performance at 50mA current, with high polystyrene yield and stable molecular weight.

[0098] -For applications requiring higher molecular weight, this can be achieved by appropriately increasing the monomer concentration.

[0099] 4. Verification of cathode polymerization mechanism using separator cell design

[0100] Key role:

[0101] In order to exclude the influence of factors such as metal deposition and to clearly identify electrical initiation as the real driving factor for polymerization, the present invention adopts a separated cell design to ensure that polymerization only occurs at the cathode.

[0102] Specific technical means:

[0103] -Construct the electrolytic cell with a physical separator to separate the anode and cathode to avoid any side reactions that may be caused by metal deposition.

[0104] -The experimental results confirmed that polymerization indeed only occurred at the cathode, proving the effectiveness and accuracy of the electrical initiation mechanism.

[0105] 5. Introduce inhibitors to verify the reaction mechanism

[0106] Key role:

[0107] There has been controversy over whether electrical initiation actually promotes polymerization or is just the result of side reactions. The present invention further confirms the existence of anionic polymerization mechanism by introducing different types of inhibitors (such as free radical inhibitors and anionic chain terminators).

[0108] Specific technical means:

[0109] After adding free radical inhibitors (such as tert-butylcatechol and p-benzoquinone), it was found that these substances had little effect on the polymerization rate, indicating that the polymerization was not dominated by free radicals.

[0110] The introduction of anionic chain terminators (such as methanol) completely inhibited the polymerization reaction, strongly supporting the view of anionic polymerization mechanism.

[0111] In summary, the key technical points of the present invention are concentrated on using tetramethylammonium salt as electrolyte, determining the appropriate current intensity range, optimizing monomer concentration, using a separator cell design to verify the cathode polymerization mechanism, and introducing an inhibitor to verify the reaction mechanism. These key technical points work together to solve the problems existing in the prior art and achieve efficient and controllable anionic electropolymerization of styrene.

[0112] In order to illustrate the progressive effects of the present invention in detail, the following are specific experimental data and tables, covering the various ranges of the most basic content of the invention, and providing examples of different numerical points of key parameters. In particular, the present invention divides the study of current intensity into Examples 1-3, and the study of monomer concentration based on the optimal current intensity is Examples 4-6. In addition, the present invention also provides some comparative examples to demonstrate the advantages of the technical solution of the present invention over the traditional method.

[0113] Experimental materials and test methods

[0114] Solvent: dimethylformamide (DMF), purchased from Sigma-Aldrich, purity ≥ 99.8%.

[0115] Tetramethylammonium salt: Tetramethylammonium chloride ((CH3)4NCl), purchased from Alfa Aesar, purity ≥98%.

[0116] Monomer: Styrene (C8H8), purchased from Merck, purity ≥99%.

[0117] Inhibitors: tert-butylcatechol (TBC), p-benzoquinone (p-BQ) and methanol (MeOH), all purchased from Sigma-Aldrich with a purity of ≥99%.

[0118] Molecular weight determination: Molecular weight was measured by intrinsic viscosity method according to ASTM D4020 standard.

[0119] Key parameter control

[0120] 1. Current intensity: set to three levels: 10mA, 50mA and 100mA.

[0121] 2. Monomer concentration: set to 20%, 40% and 70% by volume.

[0122] 3. Temperature: room temperature (about 25°C), 0°C and -8°C.

[0123] Examples and Comparative Examples

[0124] The experimental methods of the following embodiments and comparative examples are basically the same, the difference is the specific parameters therein, and the overall method is as follows:

[0125] Step 1: Build the Electrolytic Cell

[0126] Construct an electrolytic cell with a divider to ensure physical separation between the anode and cathode. This step is to verify that polymerization occurs only at the cathode and is not due to side reactions caused by metal deposition.

[0127] Step 2: Apply Current

[0128] Using a constant DC power supply, different current intensities (10 to 100 mA) are applied to the electrolytic cell at set time intervals. The current intensity is selected based on the optimal range determined experimentally to ensure efficient polymerization without causing unnecessary side reactions.

[0129] Step 3: Monitoring and Sampling

[0130] Small samples are periodically removed from the cathode area throughout the process for subsequent analysis. By determining characteristics such as the polymer content and its molecular weight, the extent and efficiency of the polymerization reaction can be assessed.

[0131] Example 1-3: Study on the influence of current intensity

[0132] Example 1: Current intensity 10mA, monomer concentration 40%

[0133] Reaction conditions: A DMF solution (containing saturated tetramethylammonium chloride) containing 40% styrene monomer was placed in an electrolytic cell and electropolymerization was carried out at a current of 10 mA for a duration of 6 hours.

[0134] Results: Polystyrene was obtained in low yield but with a molecular weight of about 15,000. The electrical efficiency was relatively low because the low current limited the anion generation rate.

[0135] Example 2: Current intensity 50mA, monomer concentration 40%

[0136] Reaction conditions: In the same solvent system, the monomer concentration was kept constant and the polymerization was carried out at a current of 50 mA for the same time.

[0137] Results: The polystyrene production increased significantly, and the molecular weight was stabilized at about 30,000, showing good electrical efficiency and molecular weight consistency. This is one of the preferred operating conditions.

[0138] Example 3: Current intensity 100mA, monomer concentration 40%

[0139] Reaction conditions: The current was further increased to 100 mA and operated under the same conditions.

[0140] Results: Although the polystyrene yield was the highest, 50 mA was selected as the optimal condition because high current may cause side reactions or excessive consumption of electrical energy.

[0141] Example 4-6: Study on the effect of monomer concentration based on the optimal current intensity

[0142] Based on the results of Example 2, 50 mA was determined to be the optimal current intensity, and the effect of monomer concentration was then studied.

[0143] Example 4: Monomer concentration 20%, current intensity 50mA

[0144] Reaction conditions: The monomer concentration was reduced to 20%, and the polymerization was carried out at 50 mA for the same time.

[0145] Results: The polystyrene yield was moderate with a molecular weight of approximately 25,000, showing good molecular weight control, but the yield was slightly lower than that at higher monomer concentrations.

[0146] Example 5: Monomer concentration 40%, current intensity 50mA

[0147] Reaction conditions: 40% monomer concentration and 50 mA current were used for polymerization for the same time.

[0148] Results: The conditions of Example 2 were repeated and the best performance was verified again, with high polystyrene yield, stable molecular weight at about 30,000, and good electrical efficiency.

[0149] Example 6: Monomer concentration 70%, current intensity 50mA

[0150] Reaction conditions: increase the monomer concentration to 70% and operate at 50 mA current.

[0151] Results: Although the polystyrene yield reached the maximum, the conductivity of the solution decreased due to the high monomer concentration, and other parameters needed to be adjusted to maintain effective polymerization; the final molecular weight was close to 50,000, showing a high molecular weight control ability, but conductivity and cost factors need to be considered in practical applications.

[0152] Table 1 Data summary

[0153]

[0154]

[0155] Comparative Example

[0156] Comparative Example 1: Free Radical Polymerization

[0157] Reaction conditions: Styrene free radical polymerization was carried out under current-free conditions using benzoyl peroxide as initiator.

[0158] Result: The obtained polystyrene has a broad molecular weight distribution, it is difficult to achieve precise molecular weight control, and the electrical efficiency cannot be measured.

[0159] Comparative Example 2: Traditional anionic polymerization

[0160] Reaction conditions: Styrene anionic polymerization was carried out using n-butyl lithium as an initiator in a strictly anhydrous and oxygen-free environment.

[0161] Result: Although a narrow molecular weight distribution can be obtained, the process is complicated, costly, and extremely sensitive to impurities, limiting its practical application.

[0162] The above test results show that the method of the present invention can not only achieve efficient and controllable styrene polymerization within a wide operating range, but also avoid many problems existing in traditional methods, such as wide molecular weight distribution, harsh reaction conditions, etc. In particular, by adjusting the current intensity and monomer concentration, the molecular weight of the polymer and its yield can be flexibly controlled, which is particularly important for industrial applications. In addition, the present invention does not require an extreme anhydrous and oxygen-free environment, which simplifies the production process and reduces costs.

[0163] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for anionic polymerization of styrene by electrochemical means, characterized in that: The following steps are involved: A tetraalkylammonium salt is added to a solvent, and the obtained solution is used as an electrolyte. Styrene monomer is added to the electrolyte, and an electric current is applied to induce a polymerization reaction of styrene.

2. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: A tetraalkylammonium salt is added to a solvent to form a saturated solution as an electrolyte, styrene monomer is added to the electrolyte, and current is applied to induce a polymerization reaction of styrene.

3. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The tetraalkylammonium salt is selected from at least one of tetramethylammonium chloride, tetraethylammonium chloride and tetrapropylammonium chloride.

4. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The solvent is selected from at least one of dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone.

5. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The reaction temperature is -8°C to 25°C.

6. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The current applied during the reaction is 10 to 100 mA.

7. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The volume concentration of styrene monomer added to the electrolyte is 20% to 70%.

8. The method for anionic polymerization of styrene by electrochemical means according to claim 1, characterized in that: The reaction time is 3 to 12 hours.

9. The method for anionic polymerization of styrene by electrochemical means according to any one of claims 1 to 8, characterized in that: The tetraalkylammonium salt is dimethylformamide, the solvent is dimethylformamide, the current applied during the reaction is 50 mA, and the volume concentration of the styrene monomer added to the electrolyte is 40%.

10. Use of the method according to any one of claims 1 to 9 in the preparation of polystyrene.

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