Method for carrying out free radical polymerization in microchannel reactor and polymer

Abstract

The invention provides a method for carrying out free radical polymerization in a microchannel reactor and a polymer, and belongs to the technical field of polymer synthesis. The method comprises the following steps: firstly, mixing a monomer and an initiator, then feeding the mixed solution into a micro-channel reactor, and carrying out free radical polymerization reaction at the temperature of more than or equal to 105 DEG C to obtain a target polymer, namely finishing free radical polymerization, the method adopts a micro-channel reactor as reaction equipment, combines a reaction mode of free radical polymerization, and controls the polymerization temperature to be greater than or equal to 105 DEG C. The method has the characteristics of high reaction speed, high production efficiency, high product conversion rate, pure product quality, no sewage treatment problem in the production process, light post-treatment task and the like; the large-scale production and application of the polymer are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis, and in particular relates to a method for free radical bulk polymerization in a microchannel reactor and a polymer. Background Art

[0002] Free radical polymerization is an important technology widely used in industry as a method for producing various polymers. However, since free radical polymerization generates large reaction heat during the polymerization reaction, the reaction needs to be carried out slowly under mild reaction conditions and over a long period of time in order to remove the reaction heat, whether it is a batch or continuous reaction, resulting in low production efficiency.

[0003] Bulk polymerization refers to the process in which no other substances are introduced during polymerization, and the amount of initiator used is small. The quality of the product obtained by polymerization is pure, and the production process does not have sewage treatment problems. The conversion rate is high, and only a small amount of unreacted monomers need to be recovered, or even no recovery is required, and the post-processing task is light. However, as the reaction of bulk polymerization continues, the molecular weight of the product becomes larger and larger, and the viscosity of the material becomes larger and larger, and self-acceleration occurs, making mass transfer and heat transfer control relatively difficult, and the quality of the product and the production capacity of the device are affected.

[0004] Microreactor technology has been developed in recent years. Due to its excellent heat and mass transfer performance, research in polymerization reactions is booming. Compared with traditional kettle polymerization, microreactors can improve the efficiency of polymerization reactions and can largely avoid side reactions, thereby better regulating the molecular weight distribution of polymers, increasing the polymerization reaction rate, and controlling the molecular structure and product morphology of polymers. From the perspective of organic synthesis, microreactors have the following characteristics: (1) They can be synthesized in small quantities; (2) They have a large surface area per unit volume (flow); (3) They are extremely easy to control temperature; (4) Reactions occur efficiently at the interface; (5) They can reduce time, cost, and environmental load; (6) Since reactions can be carried out in a sealed system, toxic and dangerous compounds can be safely synthesized; (7) Due to the small scale and closed system, pollution can be avoided; (8) By effectively utilizing the laminar flow unique to microchannels, they can be used for efficient mixing, separation, and purification of products. In addition, in terms of industrial application, since the production volume can be potentially increased by increasing the number of microreactors, it becomes possible to start production early at low cost and to quickly transfer experimental results to production as they are.

[0005] For example, CN106893015A discloses a method for preparing polymers by light-induced organic catalysis at a microscale. In a microreactor, alkyl halides are used as initiators, and organic small molecules are used as catalysts to catalyze atom transfer radical polymerization under light irradiation to prepare polymers; however, the reaction temperature of the method provided by the invention is too low and the residence time is too short, resulting in low polymerization efficiency.

[0006] For another example, CN1829745A discloses a method for producing free radical polymers, in which a free radical polymerization initiator and a free radical polymerizable monomer are introduced into a reaction tube with an inner diameter of 2 mm or less, and a polymerization reaction is carried out in the reaction tube in a uniform liquid state through circulation; however, the production method provided by the invention uses a large amount of solvent, resulting in a low monomer concentration and a low reaction rate, resulting in low production efficiency, and also has the disadvantage of heavy post-processing tasks.

[0007] Therefore, in view of the above technical problems, it is urgent to develop a free radical bulk polymerization method with fast reaction speed, high production effect and high conversion rate of the obtained polymer. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a method and a polymer for free radical bulk polymerization in a microchannel reactor, wherein the method has the advantages of fast reaction speed, high conversion rate of the obtained polymer product, and light post-processing task, and is conducive to the large-scale production and application of the polymer.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for free radical bulk polymerization in a microchannel reactor, the method comprising: mixing a monomer and an initiator, feeding the mixture into a microchannel reactor, performing a free radical bulk polymerization reaction at ≥105°C to obtain a target polymer, and completing the free radical bulk polymerization.

[0011] Firstly, the method provided by the present invention adopts a microchannel reactor as a reaction device to carry out free radical bulk polymerization. Relying on the good heat and mass transfer performance of the microchannel reactor, the reaction parameters such as reaction temperature, reactant ratio and reaction time can be more conveniently controlled by a temperature control system and flow regulation, which can effectively solve the problems of mass transfer and heat transfer control difficulties in free radical bulk polymerization. Secondly, by adopting the bulk polymerization method, no other substances are introduced during polymerization, the amount of initiator used is small, the quality of the polymerized product is pure, and the production process has no sewage treatment problem, the conversion rate is high, and only a small amount of unreacted monomers need to be recovered, or even no recovery is required. The post-processing task is light; secondly, the free radical polymerization method is adopted, which is applicable to various polymers and has the advantage of fast reaction speed, which is conducive to large-scale production; finally, the polymerization temperature is limited to ≥105℃ (for example, 105℃, 110℃, 115℃, 120℃, 140℃, 160℃, 180℃, 200℃, 210℃, 230℃, 250℃, 270℃, 290℃, 300℃ or 350℃, etc.), which can effectively increase the polymerization reaction speed and improve the production efficiency while ensuring that the obtained polymer has a high conversion rate (≥85%), which is conducive to large-scale production and application of polymers.

[0012] In some preferred embodiments, the temperature of the free radical bulk polymerization reaction is 120°C to 160°C, for example, 120°C, 122°C, 124°C, 126°C, 128°C, 130°C, 132°C, 134°C, 136°C, 138°C, 140°C, 145°C, 150°C, 155°C or 160°C, etc.

[0013] In some preferred embodiments, the free radical bulk polymerization reaction time is 20 min to 140 min, for example, 20 min, 30 min, 40 min, 50 min, 60 min, 80 min, 100 min, 120 min or 140 min, and more preferably 20 min to 30 min.

[0014] In the present invention, the time of the free radical bulk polymerization reaction is the residence time of the monomer and the initiator in the microchannel reactor, and is further related to the length of the microchannel reactor. That is to say, under the same material flow rate, the longer the length of the microchannel reactor, the longer the residence time of the monomer and the initiator in the microchannel reactor, and thus the longer the free radical bulk polymerization reaction time.

[0015] In the method provided by the present invention, the monomer comprises a free radical polymerization monomer, and the initiator comprises a free radical initiator.

[0016] As free radical polymerization monomers, the present invention has no particular limitation on the specific types thereof, as long as they are monomers capable of free radical polymerization, various monomers can be used; illustratively, the free radical polymerization monomers include olefin monomers such as ethylene, propylene, isobutylene, etc.; unsaturated monocarboxylic acid monomers such as acrylic acid and methacrylic acid; unsaturated polycarboxylic acids and anhydride monomers such as maleic acid, fumaric acid, maleic anhydride, itaconic acid, etc.; (meth) acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl methacrylate, etc.; dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, (Meth)acrylic acid dialkylaminoalkyl esters such as dimethylaminoethyl acrylate hydrochloride, dimethylaminoethyl methacrylate hydrochloride, dimethylaminoethyl acrylate p-toluenesulfonate, dimethylaminoethyl methacrylate p-toluenesulfonate and their addition salts; acrylamide monomers such as acrylamide, methacrylamide, N-hydroxymethyl acrylamide, N,N-dimethylacrylamide, acrylamide-2-methylpropanesulfonic acid and its sodium salt; styrene monomers such as styrene, α-methylvinyl, p-styrenesulfonic acid and its salts, potassium salts and the like; other oil-soluble or water-soluble monomers such as allylamine and its addition salts, vinyl acetate, acrylonitrile, methacrylonitrile, N-vinyl pyrrolidone, and fluorinated monomers such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and the like; and the above monomers can be used alone or in combination of two or more.

[0017] Similarly, as a free radical initiator, the present invention has no special restrictions on its specific type, and can be appropriately selected from the known free radical initiators used in free radical polymerization in the past according to the type of raw material free radical polymerization monomer; however, in order to be more suitable for use in the method provided by the present invention, in some preferred embodiments, the free radical initiator includes an oil-soluble organic peroxide and / or an oil-soluble azo compound; illustratively, the oil-soluble organic peroxide includes diacyl peroxides such as dibenzoyl peroxide, di-3,5,5-trimethylhexanoyl peroxide, and dilauroyl peroxide. Peroxydicarbonates such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, and di-2-ethylhexyl peroxydicarbonate, peroxyesters such as tert-butyl peroxypivalate and tert-butyl peroxyneodecanoate, or acetylcyclohexylsulfonyl peroxide, disuccinic acid peroxide, etc.; illustratively, the oil-soluble azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), etc.; the above-mentioned oil-soluble free radical initiators can be used alone or in combination of two or more.

[0018] In the method provided by the present invention, the amount of the free radical initiator used can be appropriately selected according to the types of free radical polymerization monomers and free radical initiators used, the required molecular weight of the obtained polymer, etc., but usually the amount of the free radical initiator used is 0.0001 weight part to 0.001 weight part, for example, 0.0001 weight part, 0.0002 weight part, 0.0004 weight part, 0.0005 weight part, 0.0008 weight part, 0.0009 weight part or 0.001 weight part, etc., preferably 0.0001 weight part to 0.0002 weight part, based on 100 weight parts of free radical polymerizable monomers.

[0019] In the method provided by the present invention, a chain transfer agent can be added as needed, and there is no requirement for the specific type of the chain transfer agent, as long as it does not hinder the polymerization reaction and can adjust the molecular weight of the generated polymer; illustratively, chain transfer agents such as thiols or α-methylstyrene dimer can be used; as thiol chain transfer agents, for example, 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-dodecanethiol, 2-methyl-2-heptanethiol, 2-methyl-2-undecanethiol, 2-methyl-2-propanethiol, thioglycolic acid and its esters, 3-mercaptopropionic acid and its esters, 2-mercaptoethanol and its esters, etc. are mentioned; the above-mentioned chain transfer agents can be used alone or in combination of two or more.

[0020] In some preferred embodiments, the mixing of the monomer and the initiator is performed in a mixer, more preferably in a micromixer.

[0021] In some preferred embodiments, before the mixing, the method further comprises the steps of washing and drying the monomers.

[0022] In some preferred embodiments, the monomer and the initiator are mixed and introduced into a microchannel reactor in the form of a mixed liquid to carry out a continuous polymerization reaction.

[0023] In some preferred embodiments, the diameter of the microchannel reactor is ≤2 mm, for example, 2 mm, 1.8 mm, 1.6 mm, 1.4 mm, 1.2 mm, 1 mm, 0.8 mm, 0.6 mm, 0.4 mm or 0.2 mm, etc., preferably ≤1 mm, and more preferably 0.5 mm~0.9 mm.

[0024] In some preferred embodiments, the length of the microchannel reactor is 0.01m~100m, for example, 0.01m, 0.02m, 0.04m, 0.05m, 0.1m, 0.5m, 1m, 2m, 4m, 6m, 8m, 10m, 20m, 40m, 60m, 80m or 100m, etc., further preferably 0.05m~50m, and further preferably 0.1m~10m.

[0025] In some preferred embodiments, the step of melt extrusion is further included after the free radical body polymerization is completed.

[0026] In some preferred embodiments, the melt extrusion is carried out in a devolatilizing extruder.

[0027] In a second aspect, the present invention provides a polymer, which is prepared by the method described in the first aspect.

[0028] In some preferred embodiments, the conversion rate of the polymer is ≥85%, such as 85%, 87%, 89%, 91%, 92%, 93%, 94% or 95%, etc., preferably ≥92%.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a method for performing free radical bulk polymerization in a microchannel reactor. First, a monomer and an initiator are mixed, and then the mixed solution is sent into the microchannel reactor, and a free radical bulk polymerization reaction is performed at ≥105°C to obtain a target polymer, thereby completing the free radical bulk polymerization. The method adopts a microchannel reactor as a reaction device, combines the free radical bulk polymerization method, and limits the temperature of the free radical bulk polymerization to ≥105°C, thereby having the characteristics of fast reaction speed, high production efficiency, high product conversion rate, pure product quality, no sewage treatment problem in the production process, light post-processing tasks, etc., and is conducive to large-scale production applications. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0032] Unless otherwise specified, the materials involved in the following specific implementation methods are all existing materials, and the instruments and equipment used are all existing instruments and equipment.

[0033] Example 1

[0034] A method for free radical bulk polymerization in a microchannel reactor comprises the following steps:

[0035] (1) washing methyl methacrylate three times with a 1 mol / L NaOH aqueous solution, then repeatedly washing with distilled water until neutral, then drying with anhydrous sodium sulfate, and finally bubbling with argon for more than 30 minutes to obtain pretreated methyl methacrylate;

[0036] (2) Di-3,5,5-trimethylhexanoyl peroxide and pretreated methyl methacrylate are respectively conveyed to a micro mixer through respective feed pumps for mixing, the content of di-3,5,5-trimethylhexanoyl peroxide in the micro mixer is controlled to be 100 ppm, and the mixture is fully mixed and passed in a liquid state into a microchannel reactor with a diameter of 2 mm and a length of 10 m, the temperature in the microchannel reactor is controlled to be 105° C., and the feed and discharge rates of the raw materials entering the microchannel reactor are controlled to maintain the residence time of the materials in the microchannel reactor to reach 20 min, a devolatilizing extruder is set at the discharge port, and after a period of continuous feeding and discharging, until the discharge is stable, the polymer in a molten state is collected at the outlet of the devolatilizing extruder to complete the free radical bulk polymerization.

[0037] Example 2

[0038] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 110° C., and other materials, conditions and equipment are the same as those in Example 1.

[0039] Example 3

[0040] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 120° C., and other materials, conditions and equipment are the same as those in Example 1.

[0041] Example 4

[0042] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 140° C., and other materials, conditions and equipment are the same as those in Example 1.

[0043] Example 5

[0044] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 160° C., and other materials, conditions and equipment are the same as those in Example 1.

[0045] Example 6

[0046] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 3 in that the residence time of the material in the microchannel reactor is maintained at 1 min by controlling the feed and discharge rates of the raw materials entering the microchannel reactor, and other substances, conditions and equipment are the same as those in Example 3.

[0047] Example 7

[0048] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 3 in that the residence time of the material in the microchannel reactor is maintained at 30 minutes by controlling the feed and discharge rates of the raw materials entering the microchannel reactor, and other substances, conditions and equipment are the same as those in Example 3.

[0049] Example 8

[0050] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 3 in that the residence time of the material in the microchannel reactor is maintained at 140 minutes by controlling the feed and discharge rates of the raw materials entering the microchannel reactor, and other substances, conditions and equipment are the same as those in Example 3.

[0051] Example 9

[0052] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 3 in that the content of di-3,5,5-trimethylhexanoyl peroxide in the micromixer is controlled to be 50 ppm, and other substances, conditions and equipment are the same as those in Example 1.

[0053] Example 10

[0054] A method for free radical bulk polymerization in a microchannel reactor comprises the following steps:

[0055] (1) washing methyl methacrylate three times with a 1 mol / L NaOH aqueous solution, then repeatedly washing with distilled water until neutral, then drying with anhydrous sodium sulfate, and finally bubbling with argon for more than 30 minutes to obtain pretreated methyl methacrylate;

[0056] (2) Di-3,5,5-trimethylhexanoyl peroxide and pretreated styrene are respectively conveyed to a micro mixer through respective feed pumps for mixing, the content of di-3,5,5-trimethylhexanoyl peroxide in the micro mixer is controlled to be 100 ppm, and the mixture is fully mixed and passed in a liquid state into a microchannel reactor with a diameter of 1 mm and a length of 40 m, and the temperature in the microchannel reactor is controlled to be 120° C., and the feed and discharge rates of the raw materials entering the microchannel reactor are controlled to maintain the residence time of the materials in the microchannel reactor to reach 20 min, and a devolatilizing extruder is set at the discharge port. After a period of continuous feeding and discharging, until the discharge is stable, the polymer in a molten state is collected at the outlet of the devolatilizing extruder to complete the free radical bulk polymerization.

[0057] Embodiment 11

[0058] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 10 in that the residence time of the material in the microchannel reactor is maintained at 10 minutes by controlling the feed and discharge rates of the raw materials entering the microchannel reactor, and other substances, conditions and equipment are the same as those in Example 10.

[0059] Example 12

[0060] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 10 in that the content of di-3,5,5-trimethylhexanoyl peroxide in the micromixer is controlled to be 50 ppm, and other substances, conditions and equipment are the same as those in Example 1.

[0061] Embodiment 13

[0062] A method for free radical bulk polymerization in a microchannel reactor, which differs from Example 10 in that the temperature in the microchannel reactor is controlled to be 140°C, and other materials, conditions and equipment are the same as those in Example 1.

[0063] Comparative Example 1

[0064] A method for free radical bulk polymerization comprises the following steps:

[0065] (1) washing methyl methacrylate three times with a 1 mol / L NaOH aqueous solution, then repeatedly washing with distilled water until neutral, then drying with anhydrous sodium sulfate, and finally bubbling with argon for more than 30 minutes to obtain pretreated methyl methacrylate;

[0066] (2) Di-3,5,5-trimethylhexanoyl peroxide and pretreated methyl methacrylate are respectively conveyed to a micro mixer through respective feed pumps for mixing, the content of di-3,5,5-trimethylhexanoyl peroxide in the micro mixer is controlled to be 100 ppm, and the mixture is fully mixed and introduced into a tank reactor in a liquid state, the temperature in the tank reactor is controlled to be 105° C., and the feed and discharge rates of the raw materials into and out of the tank reactor are controlled to maintain the residence time of the materials in the tank reactor to reach 20 minutes, a devolatilizing extruder is set at the discharge port, and after a period of continuous feeding and discharging, until the discharge is stable, the polymer in a molten state is collected at the outlet of the devolatilizing extruder to complete the free radical bulk polymerization.

[0067] Comparative Example 2

[0068] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the temperature in the autoclave reactor is controlled to be 110° C., and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0069] Comparative Example 3

[0070] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the temperature in the autoclave reactor is controlled to be 120° C., and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0071] Comparative Example 4

[0072] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the temperature in the autoclave reactor is controlled to be 140° C., and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0073] Comparative Example 5

[0074] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the temperature in the autoclave reactor is controlled to be 160° C., and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0075] Comparative Example 6

[0076] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the material feeding and discharging rates into the autoclave reactor are controlled to maintain the material residence time in the autoclave reactor at 1 min, and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0077] Comparative Example 7

[0078] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the material feeding and discharging rates into the autoclave reactor are controlled to maintain the material residence time in the autoclave reactor at 30 minutes, and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0079] Comparative Example 8

[0080] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the material feeding and discharging rates into the autoclave reactor are controlled to maintain the material residence time in the autoclave reactor at 140 minutes, and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0081] Comparative Example 9

[0082] A method for free radical bulk polymerization, which differs from Comparative Example 1 in that the content of di-3,5,5-trimethylhexanoyl peroxide in the autoclave reactor is controlled to be 50 ppm, and other materials, conditions and equipment are the same as those in Comparative Example 1.

[0083] Comparative Example 10

[0084] A method for free radical bulk polymerization, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 100° C., and other materials, conditions and equipment are the same as those in Example 1.

[0085] Comparative Example 11

[0086] A method for free radical bulk polymerization, which differs from Example 1 in that the temperature in the microchannel reactor is controlled to be 90° C., and other materials, conditions and equipment are the same as those in Example 1.

[0087] Result analysis:

[0088] (1) Polymerization temperature and time: record the temperature and time of the free radical polymerization reaction.

[0089] (2) Polymer conversion rate: After the polymerization time is reached, the polymer product is collected at the reactor outlet for 10 seconds and weighed and recorded as ;

[0090] At the same time, during this 10 s, the mass of the monomer and initiator mixture entering the reactor is recorded as ;

[0091] Conversion rate η (%) = ×100%.

[0092] The results of Examples 1 to 13 and Comparative Examples 1 to 11 were statistically analyzed according to the above method and summarized in Table 1;

[0093] Table 1

[0094]

[0095] From the data in Table 1, we can see that:

[0096] By comparing the data of Examples 1 to 13 and Comparative Examples 1 to 9, it can be seen that under the same reaction conditions, the conversion rate of the polymer obtained by free radical bulk polymerization using a microchannel reactor is higher than the conversion rate of the polymer obtained by free radical bulk polymerization using a conventional reactor.

[0097] Comparing the data of Examples 1 to 13 and Comparative Examples 10 to 11, it can be seen that if the reaction temperature of the free radical bulk polymerization using a microchannel reactor is too low, not only the reaction rate will be affected, but also the conversion rate of the obtained polymer will be reduced.

[0098] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate a method and polymer for free radical bulk polymerization in a microchannel reactor, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for free radical bulk polymerization in a microchannel reactor, characterized in that: The method comprises: mixing monomers and initiators, feeding the mixture into a microchannel reactor, performing free radical bulk polymerization at a temperature of ≥105° C., obtaining a target polymer, and completing the free radical bulk polymerization.

2. The method according to claim 1, characterized in that The temperature of the free radical bulk polymerization reaction is 120°C to 160°C.

3. The method according to claim 1, characterized in that The free radical polymerization reaction time is 20min to 140min.

4. The method according to claim 1, characterized in that The monomer includes a free radical polymerization monomer, and the initiator includes a free radical initiator; And based on 100 parts by weight of the free radical polymerization monomer, the amount of the free radical initiator is 0.0001 parts by weight to 0.001 parts by weight.

5. The method according to claim 1, characterized in that The monomer and the initiator are mixed and introduced into the microchannel reactor in the form of a mixed liquid to carry out a continuous free radical bulk polymerization reaction.

6. The method according to claim 1, characterized in that The diameter of the microchannel reactor is ≤2 mm.

7. The method according to claim 1, characterized in that The length of the microchannel reactor is 0.01m~100m.

8. The method according to claim 1, characterized in that: After the free radical polymerization reaction is completed, a melt extrusion step is also included.

9. A polymer, characterized in that The polymer is prepared by the method according to any one of claims 1 to 8.

10. The polymer according to claim 9, characterized in that The conversion rate of the polymer is ≥85%.

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