A polymerization method based on free radical rearrangement reaction and its polymer

Abstract

The present invention discloses a polymerization method based on radical rearrangement reaction and its polymer, belonging to the technical field of polymerization of polymers. In the present invention, a polymerization monomer and an initiator are mixed and heated to react to obtain a polymer. Among them, the polymerization monomer is an olefin compound, the olefin compound contains more than 5 carbon atoms, and includes a rearrangeable functional group and an electron-withdrawing group; the initiator includes a compound that can generate free radicals under light conditions and / or thermal conditions. By using the radical rearrangement reaction strategy, only by providing heating conditions and / or light conditions, the initiator can generate free radicals to initiate the polymerization of the polymerization monomer to form a polymer. The whole reaction process is easy to operate, the reaction conditions are mild, no auxiliary agents such as catalysts need to be added, the polymerization cost is low, the conversion rate is high, the obtained polymer has a relatively high molecular weight, a relatively narrow molecular weight distribution, less impurity content, high purity, stable structure, and has a certain hardness and elasticity.

Description

Technical Field

[0001] The present invention relates to the technical field of polymerization of polymers, and particularly relates to a polymerization method based on radical rearrangement reaction and its polymer. Background Art

[0002] Polymers are divided into natural polymers and synthetic polymers. Natural polymers are usually prepared from natural plants by physical or chemical methods, and synthetic polymers are obtained by polymerizing low-molecular polymer monomers through polymerization reactions. The polymerization methods of synthetic polymers usually include bulk (melt) polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc. Different methods can be selected according to the performance requirements of the polymers. For example, the polymerization of monomers with functional groups often uses solution or melt polymerization methods.

[0003] The above polymerization methods usually require the addition of some auxiliary agents such as catalysts, or there are problems such as complex preparation conditions and many impurities in the polymers obtained by polymerization. The traditional polymerization methods and the synthesized polymers can no longer meet the needs of modern society, and there is an urgent need for new polymerization processes and innovative polymerization methods to synthesize polymers with novel structures. Therefore, it is of great value to research and develop a polymerization method with simple operation, mild process conditions, high conversion rate, and novel polymerization mode.

[0004] Radical rearrangement reactions can cause functional groups to rearrange from one atom to another through consecutive chemical bond cleavage and recombination. Moreover, the process of functional group rearrangement reactions often breaks through the limitations of bond energy and spatial distance in traditional reaction processes. In the past few years, organic chemists have discovered many new types of radical rearrangement reactions and types of rearrangement reaction groups: in addition to unsaturated functional groups (aryl, heteroaryl, cyano, oxime, alkenyl, alkynyl, carbonyl, etc.), heteroatoms (halogen atoms, silicon, boron, etc.) also exhibit good rearrangement reaction properties. This strategy is often cleverly applied to the reorganization of molecular skeletons, thus evolving into a powerful tool for important synthetic transformations.

[0005] With the rise of radical chemistry in recent years, radical rearrangement reactions have gradually become a popular emerging research field. In the "Research Frontiers 2019" jointly released by the Chinese Academy of Sciences and Clarivate Analytics to the world, it was selected as one of the 5 key emerging frontier fields in chemistry and materials science. This invention is based on the research of radical rearrangement reactions, applies it to the synthesis of polymers, and the polymers synthesized through the application of this theory have novel structures, excellent properties, and potential application values. Summary of the Invention

[0006] The main object of the present invention is to provide a polymerization method based on radical rearrangement reaction and its polymer with simple operation, mild process conditions, high conversion rate, and low cost.

[0007] To achieve the above object, the present invention provides a polymerization method based on a radical rearrangement reaction, comprising the following steps:

[0008] Mix a polymerization monomer and an initiator, and heat the reaction to obtain a polymer;

[0009] Wherein,

[0010] The polymerization monomer is an olefin compound, the olefin compound contains more than 5 carbon atoms, and includes a migratable functional group and an electron-withdrawing group;

[0011] The initiator includes a compound that can generate free radicals under light conditions and / or thermal conditions.

[0012] In some embodiments of the present application, the electron-withdrawing group in the polymerization monomer includes -CN, -F, -Cl, -COOR3, -SO2Ph, -NO2, etc.; wherein, R3 in the -COOR3 includes an aliphatic chain;

[0013] And / or, the migratable functional group in the polymerization monomer includes an unsaturated functional group or a heteroatom. The unsaturated functional group includes a cyano group, an aryl group, a heteroaryl group, an oxime group, an alkenyl group, an alkynyl group or a carbonyl group, etc. The heteroatom includes a halogen atom, silicon or boron, etc.; In some embodiments of the present application, the polymerization monomer has the following general structural formula:

[0014]

[0015] Wherein,

[0016] The R1 group in the polymerization monomer is the electron-withdrawing group or the migratable reactive functional group as described above in the present invention;

[0017] The R2 group in the polymerization monomer is the electron-withdrawing group or the migratable functional group as described above in the present invention.

[0018] In some embodiments of the present application, the initiator includes at least one of an organic peroxide and an azo compound.

[0019] In some embodiments of the present application, the organic peroxide includes at least one of an acyl peroxide, a hydroperoxide, a dialkyl peroxide, an ester peroxide, a ketone peroxide, a dicarbonate peroxide;

[0020] And / or, the azo compound includes at least one of azodiisobutyronitrile, azodiisoheptonitrile, azodiisovaleronitrile, azodicyclohexylmethyl cyanide, dimethyl azodiisobutyrate.

[0021] In some embodiments of the present application, the acyl peroxides include at least one of benzoyl peroxide and lauroyl peroxide.

[0022] In some embodiments of the present application, the hydroperoxides include at least one of cumene hydroperoxide and tert-butyl hydroperoxide.

[0023] In some embodiments of the present application, the dialkyl peroxides include at least one of di-tert-butyl peroxide and dicumyl peroxide.

[0024] In some embodiments of the present application, the ester peroxides include at least one of tert-butyl peroxybenzoate and tert-butyl peroxy pivalate.

[0025] In some embodiments of the present application, the ketone peroxides include at least one of methyl ethyl ketone peroxide and cyclohexanone peroxide.

[0026] In some embodiments of the present application, the dicarbonate peroxides include at least one of diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

[0027] In some embodiments of the present application, the molar ratio of the polymerization monomer to the initiator is 100:(1 - 20).

[0028] In some embodiments of the present application, the temperature of the heating reaction is 35 °C or higher.

[0029] In some embodiments of the present application, the heating reaction is carried out in an atmosphere of protective gas or air, and the protective gas includes nitrogen or argon.

[0030] In some embodiments of the present application, in the step of mixing the polymerization monomer and the initiator, the polymerization monomer and the initiator can also be dissolved and mixed in an organic solvent.

[0031] In some embodiments of the present application, based on the volume mL of the organic solvent, the addition amount of the polymerization monomer is (1 - 20) mmol / mL, but it is not limited to the above reaction concentration range. Experimental results prove that the greater the reaction concentration in the reaction system, the more favorable it is for the polymerization reaction.

[0032] In some embodiments of the present application, the organic solvent includes at least one of ethanol, acetonitrile, acetone, dimethyl sulfoxide, N,N-dimethylformamide, and ethyl acetate.

[0033] To achieve the above object, the present application also provides a polymer prepared by the polymerization method based on the radical rearrangement reaction as described above in the present invention.

[0034] In some embodiments of the present application, the molecular weight of the polymer is above 1000.

[0035] In some embodiments of the present application, the polydispersity index (PDI) of the polymer is 1.20 - 4.00.

[0036] In some embodiments of the present application, the conversion rate of the polymerization monomer is 29% - 98%.

[0037] In some embodiments of the present application, the polymer contains acrylonitrile structural units, and the content range of acrylonitrile structural units in the polymer is 23% - 88%.

[0038] In some embodiments of the present application, the polymer has the following general structural formula:

[0039]

[0040] R1 in the general structural formula is a migratable functional group;

[0041] R2 in the general structural formula is an electron-withdrawing group;

[0042] n in the general structural formula is greater than or equal to 1.

[0043] In some embodiments of the present application, the polymer has the following general structural formula (Ⅰ): n in the general structural formula (Ⅰ) is greater than or equal to 1;

[0044] Or, the polymer has the general structural formula (Ⅱ):

[0045] n in the general structural formula (Ⅱ) is greater than or equal to 1;

[0046] Or, the polymer has the general structural formula (Ⅲ):

[0047] n in the general structural formula (Ⅲ) is greater than or equal to 1;

[0048] Or, the polymer has the general structural formula (Ⅳ):

[0049] n in the general structural formula (Ⅳ) is greater than or equal to 1;

[0050] Or, the polymer has the general structural formula (Ⅴ):

[0051] n in the general structural formula (Ⅴ) is greater than or equal to 1;

[0052] Or, the polymer has the general structural formula (Ⅵ):

[0053] In the general structural formula (VI), n is greater than or equal to 1.

[0054] Advantages achievable by the present invention:

[0055] By using the free radical rearrangement reaction strategy, the present invention only needs to provide heating conditions or light conditions, and the initiator can generate free radicals to initiate the polymerization of polymerizable monomers to form polymers. The whole reaction process is easy to operate, the reaction conditions are mild, no auxiliary agents such as catalysts need to be added, the polymerization cost is low, the conversion rate of polymerizable monomers is high, the obtained polymers have less impurity content, high purity, stable structure, certain hardness and elasticity, and the obtained polymers have a relatively high molecular weight and a relatively narrow molecular weight distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0057] Figure 1 It is the nuclear magnetic resonance hydrogen spectrum of polymerizable monomer a in Examples 1 to 18 of the present invention.

[0058] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum of the polymerizable monomer in Example 20 of the present invention.

[0059] Figure 3 It is the nuclear magnetic resonance hydrogen spectrum of the polymer obtained in Example 1 of the present invention.

[0060] Figure 4 It is the nuclear magnetic resonance hydrogen spectrum of the polymer obtained in Example 20 of the present invention.

[0061] Figure 5 It is the thermogravimetric curve of the polymer obtained in Example 1 of the present invention.

[0062] Figure 6 It is the physical picture of the polymer obtained in Example 1 of the present invention.

[0063] Figure 7 It is the physical picture of the polymer obtained in Example 20 of the present invention.

[0064] The realization, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0066] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0067] In the present invention, descriptions such as "first" and "second" are only for descriptive purposes, and cannot be construed as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0068] The present invention provides a polymerization method based on a radical rearrangement reaction, comprising the following steps:

[0069] Mix a polymerization monomer and an initiator, and heat the reaction to obtain a polymer; wherein,

[0070] The polymerization monomer is an olefin compound, the olefin compound contains more than 5 carbon atoms, and includes a migratable functional group and an electron-withdrawing group;

[0071] It should be noted that the olefin compound containing more than 5 carbon atoms can be understood as that the main chain of the olefin compound contains at least 5 carbon atoms. The main chain of the olefin compound contains at least 5 carbon atoms, which is beneficial to the polymerization of the polymerization monomer to form a polymer through a radical rearrangement reaction.

[0072] The initiator includes a compound that can generate free radicals under light conditions and / or thermal conditions.

[0073] The reaction mechanism of the polymerization reaction based on the radical rearrangement reaction of the present invention is as follows: Under heating conditions and / or light conditions, the initiator generates free radicals, and undergoes an addition reaction with the polymerization monomer to form an alkyl radical, generating a new radical center; then, the new radical center continues to react with the migratable functional group in the polymerization monomer, promoting the migration of the functional group to the distal carbon atom; at this time, the radical center changes again, and then continues to repeat the above reaction process with another molecule of the polymerization monomer, and uses the radical rearrangement reaction strategy to carry out the polymerization reaction, and finally obtains a polymer.

[0074] The present invention provides an embodiment herein to explain the reaction mechanism of the polymerization reaction based on the radical rearrangement reaction. However, it should be noted that the following embodiment is only one of the technical solutions of the present invention and does not constitute a limitation to the technical solutions of the present invention.

[0075] In this embodiment, the polymerization monomer is monomer a, the migratable group in monomer a is -CN, the electron-withdrawing group is R1, and at the same time, R is used as the initiator. The polymerization reaction process based on the radical rearrangement reaction is as follows:

[0076]

[0077] The initiator R generates radicals, which react with the polymerization monomer to form alkyl radical b, generating a new radical center. This radical adds to the unsaturated bond in -CN to form cyclic imine radical c. Subsequently, the C-C bond in the cyclic imino radical c breaks, realizing the 1,4-migration reaction of -CN, and at the same time forming d alkyl radical. Due to the presence of the electron-withdrawing group R1, the alkyl radical d is prone to continue the above reaction with another molecule of olefin monomer a to form a dimer radical. The above reaction process is continuously repeated in the reaction system, and finally a polymer is formed.

[0078] In some embodiments, the electron-withdrawing groups in the polymerization monomer include -CN, -F, -Cl, -COOR3, -SO2Ph, -NO2, etc. Among them, R3 in -COOR3 includes an aliphatic chain. The above types of electron-withdrawing groups can promote the rearrangement reaction of the migratable reaction functional group, enabling it to migrate to the distal carbon atom and providing a polymerization reaction site for the next polymerization monomer.

[0079] In some embodiments, the migratable functional groups in the polymerization monomer include unsaturated functional groups or heteroatoms. The unsaturated functional groups include cyano group, aryl group, heteroaryl group, oxime group, alkenyl group, alkynyl group or carbonyl group, etc., and the heteroatoms include halogen atoms, silicon or boron, etc. The above types of migratable functional groups can undergo rearrangement reactions under the induction of radicals, migrate to the distal carbon atoms, and the initiator can continuously introduce new polymerization monomers, and finally complete the polymerization reaction to obtain a polymer.

[0080] In some embodiments, the polymerization monomer has the following general structural formula:

[0081]

[0082] Among them, the R1 group in the polymerization monomer is an electron-withdrawing group or a migratable functional group, and / or the R2 group in the polymerization monomer is an electron-withdrawing group or a migratable functional group. It should be noted that when the R1 group in the polymerization monomer of this embodiment is an electron-withdrawing group, the R2 group is a migratable functional group; when the R1 group is a migratable functional group, the R2 group is an electron-withdrawing group.

[0083] The present invention does not limit the type of initiator. In some embodiments, the initiator includes at least one of organic peroxides and azo compounds. The above types of initiators can generate free radicals under light conditions and / or thermal conditions, react with the polymerization monomer to obtain alkyl free radicals, and generate a new free radical center, promoting the migration of the migratable functional group in the polymerization monomer, and continuously introducing new polymerization monomers by using the strategy of free radical rearrangement reaction, and finally obtaining a polymer.

[0084] In some embodiments, the organic peroxide includes at least one of acyl peroxides, hydroperoxides, dialkyl peroxides, ester peroxides, ketone peroxides, and dicarbonate peroxides.

[0085] In some embodiments, the azo compound includes at least one of azobisisobutyronitrile, azobisisoheptonitrile, azobisisopentanenitrile, azobiscyclohexylcarbonitrile, and dimethyl azobisisobutyrate.

[0086] In some embodiments, the acyl peroxide includes at least one of benzoyl peroxide and lauroyl peroxide.

[0087] In some embodiments, the hydroperoxide includes at least one of cumene hydroperoxide and tert-butyl hydroperoxide.

[0088] In some embodiments, the dialkyl peroxide includes at least one of di-tert-butyl peroxide and diisopropylbenzene peroxide.

[0089] In some embodiments, the ester peroxide includes at least one of tert-butyl peroxybenzoate and tert-butyl peroxy-tert-pentanoate.

[0090] In some embodiments, the ketone peroxide includes at least one of methyl ethyl ketone peroxide and cyclohexanone peroxide.

[0091] In some embodiments, the dicarbonate peroxide includes at least one of diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

[0092] The above types of initiators can generate free radicals under relatively low temperature conditions, and then promote the rearrangement reaction of the migratable functional group of the polymerization monomer, continuously introduce new polymerization monomers, and finally obtain a polymer.

[0093] It should be noted that the initiator of the present invention is not limited to the types listed above. The initiator of the present invention includes all compounds that can generate free radicals under light conditions and / or thermal conditions. For example, when the initiator is a dithioester compound, the initiator can generate free radicals under light conditions, thereby promoting the rearrangement reaction of the migratable functional groups of the polymerizable monomers, continuously introducing new polymerizable monomers, and finally obtaining a polymer.

[0094] The present invention does not limit the molar ratio of the polymerizable monomer to the initiator in the polymerization reaction. In some embodiments, the molar ratio of the polymerizable monomer to the initiator is 100:(1 - 20). For example, the molar ratio can be any one of 100:1, 100:2, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19, 100:20, etc. within the range of 100:(1 - 20). However, it is not limited only to the above-listed ratio ranges.

[0095] In some embodiments, the temperature of the heating reaction is above 35°C. For example, the heating temperature can be 35°C, 45°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc., which are reaction temperatures above 35°C. The present invention can prompt the initiator to generate free radicals and initiate the polymerization of the polymerizable monomers to obtain a polymer under relatively mild conditions.

[0096] It should be noted that the above-listed temperature conditions are only some embodiments of the present invention. The present invention does not limit the temperature of the heating reaction, and the temperature of the heating reaction can be adjusted according to the temperature at which the initiator generates free radicals.

[0097] In some embodiments, the heating reaction time is any reaction time above 4h. For example, the reaction time can be any one of 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 20h, 30h, 40h, 50h, etc. above 4h. Under the above limitation of the heating reaction time, it is beneficial to obtain a polymer with a relatively high conversion rate.

[0098] The present invention does not limit the reaction atmosphere of the polymerization reaction, and the polymerization conditions are mild and simple. In some embodiments, the polymerization reaction can be carried out under air conditions, and in other embodiments, the polymerization reaction can also be carried out in a protective gas atmosphere, and the protective gas includes nitrogen or argon.

[0099] The present invention utilizes the method of free radical rearrangement reaction. Only under heating conditions or light conditions, the initiator can generate free radicals to initiate the polymerization of monomers to complete the polymerization reaction to form a polymer. The whole reaction is easy to operate, the reaction conditions are mild, and there is no need to add auxiliary agents such as catalysts. The polymerization cost is relatively low, the conversion rate of polymerization monomers is high, the obtained polymer has less impurity content, high purity, stable structure, certain hardness and elasticity, and the obtained polymer has a relatively high molecular weight and a relatively narrow molecular weight distribution. In addition, in some embodiments, the polymer prepared by the present invention can also have a structure similar to that of hydrogenated nitrile rubber, and the content of acrylonitrile structural units can be as high as 88%, which is much higher than the acrylonitrile content of all hydrogenated nitrile rubbers currently sold on the market. The technical solution of the present invention has potential market application prospects.

[0100] It should be noted that the polymerization method based on free radical rearrangement reaction of the present invention does not need to add auxiliary agents such as catalysts. It can be understood that the polymerization method based on free radical rearrangement reaction of the present invention can complete the polymerization reaction to obtain a polymer even without the assistance of catalysts and other auxiliary agents, but it does not mean that the polymerization method of the present invention cannot add catalysts and other auxiliary agents.

[0101] For example, in some embodiments, in the step of mixing the polymerization monomer and the initiator, the polymerization monomer and the initiator can also be dissolved and mixed with an organic solvent. The organic solvent can promote the dissolution of the polymerization monomer and the initiator and make their mixing more uniform.

[0102] The present invention does not limit the reaction concentration of the polymerization monomer in the organic solvent. The greater the reaction concentration, the more favorable for the progress of the polymerization reaction. In some embodiments, based on the volume mL of the organic solvent, the addition amount of the polymerization monomer is (1 - 20) mmol / mL. The above content ratio of the organic solvent and the polymerization monomer is only some embodiments listed in the present invention and does not constitute a limitation to the technical solution of the present invention.

[0103] The present invention does not limit the type of the organic solvent. In some embodiments, the organic solvent includes at least one of ethanol, acetonitrile, acetone, dimethyl sulfoxide, N,N-dimethylformamide, and ethyl acetate. The above organic solvents have good solubility for the polymerization monomer and the initiator, can promote the mixing of the polymerization monomer and the initiator to be more uniform, and promote the progress of the polymerization reaction.

[0104] The present invention also provides a polymer prepared by the polymerization method based on free radical rearrangement reaction as described above.

[0105] The present invention does not limit the molecular weight of the prepared polymer. In some embodiments, the molecular weight of the polymer of the present invention is above 1000. For example, the molecular weight of the polymer is 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 20000, 30000, 40000, 50000, 55000, 60000, 70000, 75000, 78000, 79000, 80000, 81000, 83000, 85000, 87000, 88000, 89000, 90000, 95000, 100000, etc., any molecular weight above 1000. The present invention can control the molecular weight of the polymer by controlling the addition amounts of the polymerization monomer and the initiator, as well as the temperature and time of the heating reaction, so as to obtain a polymer with a relatively large molecular weight span to meet different production requirements. Moreover, because the entire polymerization reaction process is easy to operate and the conditions are mild, the reaction conditions can be easily adjusted to obtain polymers with different molecular weights to meet the production requirements.

[0106] In some embodiments, the polydispersity index (PDI) of the polymer of the present invention is 1.20 - 4.00, the distribution width is relatively narrow, and the physical properties of the polymer are relatively stable. In one embodiment, the distribution width of the polymer can be any value in the range of 1.20 - 4.00, such as 1.20, 1.40, 1.60, 1.80, 2.00, 2.20, 2.40, 2.60, 2.80, 3.00, 3.20, 3.40, 3.60, 3.80, 4.00.

[0107] In some embodiments, the conversion rate of the polymerization monomer of the present invention is 29% - 98%. For example, the conversion rate of the polymerization monomer is 29%, 30%, 32%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 93%, 95%, 96%, 97%, 98%, etc., any conversion rate in the range of 29% - 98%. The conversion rate of the monomer is related to factors such as the reaction temperature, reaction time, and initiator dosage.

[0108] In some embodiments, when the migratable group in the polymerization monomer is -CN, the obtained polymer contains a structural unit of acrylonitrile, and the presence of the acrylonitrile structure endows the polymer with oil resistance, wear resistance, and relatively high mechanical strength.

[0109] In some embodiments, the content of acrylonitrile structural units in the polymer of the present invention ranges from 23% to 88%. For example, the content of acrylonitrile structural units can be any value within the range of 23% - 88%, such as 23%, 23%, 25%, 28%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 73%, 75%, 78%, 79%, 80%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, etc. The conversion rate of the polymerization monomer is relatively high, and a polymer with a high content of acrylonitrile structural units can be obtained, enabling the polymeric material to have excellent use properties.

[0110] In some embodiments, the polymer of the present invention has the following general structural formula:

[0111]

[0112] In the general structural formula of the polymer in this embodiment, R1 is a migratable functional group, and R2 is an electron-withdrawing group; n is greater than or equal to 1, and R1 and R2 depend on the structure of the initiator and the structure of the polymerization monomer.

[0113] Furthermore, the polymer of the present invention has the following general structural formula:

[0114]

[0115] In the general structural formula of the polymer in this embodiment, n is greater than or equal to 1. The polymer in this embodiment is obtained by mixing and heating a polymerization monomer and an azobisisobutyronitrile initiator and polymerizing by means of free radical rearrangement. The migratable functional group in the polymerization monomer is -CN, and R2 is an electron-withdrawing group. In some embodiments, the above polymer is a viscous transparent solid or a yellow solid, has viscosity or elasticity, is similar to an adhesive or an elastomer, and the hardness of the polymer obtained varies according to the different polymerization monomers. For example, when R2 is -CN, the obtained polymer has a certain elasticity and hardness; when R2 is -COOR3 (R3 includes an aliphatic chain), the obtained polymer has a certain viscosity and can even be drawn into filaments.

[0116] In some embodiments, the polymer of the present invention has the following general structural formula (I):

[0117] In the general structural formula (Ⅰ), n is greater than or equal to 1. The polymer of this example is polymerized from polymerization monomers in which both the migratable functional group and the electron-withdrawing group are -CN. The resulting polymer contains structural units of acrylonitrile and has a structure similar to that of hydrogenated nitrile rubber. The presence of the acrylonitrile structure endows the polymer with oil resistance, wear resistance, and relatively high mechanical strength. Moreover, the content of the acrylonitrile structural units in the polymer of the present invention can be as high as 88%, which is much higher than the acrylonitrile content of all hydrogenated nitrile rubbers currently sold on the market, and has potential market application prospects.

[0118] In some embodiments, the polymer has the general structural formula (Ⅱ):

[0119] In the general structural formula (Ⅱ), n is greater than or equal to 1. The polymer of this example contains structural units of acrylonitrile and ester groups. The presence of the acrylonitrile structure endows the polymer with oil resistance and wear resistance, and the presence of the ester groups makes the polymer molecular chain relatively flexible, having certain viscosity and spinnability.

[0120] In some embodiments, the polymer of the present invention has the general structural formula (Ⅲ):

[0121] In the general structural formula (Ⅲ), n is greater than or equal to 1. The polymer of this example contains structural units of acrylonitrile and ester groups. The presence of the acrylonitrile structure endows the polymer with oil resistance, wear resistance, and certain strength. Similarly, the presence of the ester groups makes the polymer chain flexible, and the overall polymer has certain viscosity.

[0122] In some embodiments, the polymer has the general structural formula (Ⅳ):

[0123] In the general structural formula (Ⅳ), n is greater than or equal to 1. The polymer of this example contains structural units of acrylonitrile and amide groups. The presence of the acrylonitrile structure endows the polymer with oil resistance, wear resistance, and relatively high mechanical strength. The presence of the amide groups endows the polymer with certain elasticity and viscosity, and has certain application prospects in special fields.

[0124] In some embodiments, the polymer has the general structural formula (Ⅴ):

[0125] In the general structural formula (Ⅴ), n is greater than or equal to 1. The polymer of this example contains structural units of acrylonitrile. The presence of the acrylonitrile structure endows the polymer with oil resistance, wear resistance, and relatively high mechanical strength. Similarly, the presence of the benzene ring in the side chain further increases the rigidity of the polymer and further improves its hardness.

[0126] In some embodiments, the polymer has the general structural formula (Ⅵ):

[0127] In the structural general formula (VI), n is greater than or equal to 1. The polymer of this embodiment contains structural units of acrylonitrile and phospholipid groups. The structural units of acrylonitrile endow the polymer with oil resistance, wear resistance and relatively high mechanical strength. The presence of phospholipids endows the polymer with certain fire resistance and can be used as a flame retardant material. At the same time, this material is also a new type of polymer material.

[0128] It should be noted that the polymerization monomers listed above are only some embodiments of the technical solution of the present invention and do not limit the technical solution of the present invention.

[0129] The present invention does not limit the preparation methods of all the above-mentioned types of polymerization monomers, and the preparation methods well-known to those skilled in the art can be selected for preparation.

[0130] Here, the present invention provides a preparation method of a polymerization monomer, but this preparation method cannot be regarded as a limitation to the technical solution of the present invention.

[0131] In some embodiments, the preparation method of the polymerization monomer includes the following steps:

[0132] Step 1, Weigh NaH (1.2 equiv.) into a two-necked flask, seal and displace nitrogen three times, add N,N-dimethylformamide at 0 °C, and stir for 30 min to obtain a reaction solution.

[0133] Step 2, Slowly add (2.0 equiv.) to the reaction solution in Step 1, continue to stir at 0 °C for 0.5 h to 2 h, and then add (1.0 equiv.) to the reaction system. Among them, The R1 group in is an electron-withdrawing group, which can be -CN, -F, -Cl, -COOR3 (R3 is an aliphatic chain), -SO2Ph or -NO2; The X group in includes -Cl, -Br.

[0134] Step 3, Use thin-layer chromatography to detect the reaction result. After determining that the reaction is over, quench the reaction with saturated NH4Cl solution, then extract with ethyl acetate to obtain the reaction product, and then purify the reaction product by vacuum distillation or column chromatography.

[0135] The following further elaborates on the technical solution of the present invention in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not used to limit the present invention.

[0136] Preparation of polymerization monomer a

[0137] The preparation method of polymerization monomer a in this embodiment includes the following steps:

[0138] Step 1: Weigh NaH (1.2 equiv.) into a two-necked flask, seal it and displace nitrogen three times. Dissolve it in N,N-dimethylformamide at 0 °C and stir for 30 min to obtain a reaction solution.

[0139] Step 2: Slowly add (2.0 equiv.) to the reaction solution in Step 1, continue to stir at 0 °C for 0.5 h to 2 h, and then add (1.0 equiv.) to the reaction system.

[0140] Step 3: Detect the reaction result by thin-layer chromatography. After confirming the end of the reaction, quench the reaction with saturated NH4Cl solution, then extract with ethyl acetate to obtain the reaction product, and purify the reaction product by vacuum distillation or column chromatography.

[0141] The polymer monomer a prepared in this example has the following structural formula: That is, the electron-withdrawing group in the polymer monomer a is -CN, and the migratable functional group is -CN.

[0142] Characterize the polymer monomer a with a nuclear magnetic resonance hydrogen spectrometer, and the characterization results are as shown in Figure 1 and Figure 2 shown. Figure 1 is the hydrogen spectrum of the polymer monomer a, Figure 2 is the carbon spectrum of the polymer monomer a. Combining Figure 1 and Figure 2 can determine that the polymer monomer a obtained in this example has the following structure: Examples 1 to 17

[0143] The polymerization methods of Examples 1 to 17 based on free radical rearrangement reaction include the following steps:

[0144] Place 5 mmol of polymer monomer a in a pressure-resistant tube according to the reactant conditions in Table 1, then add an initiator, evacuate and replace nitrogen three times, and then carry out a heating reaction under a nitrogen atmosphere according to the reaction conditions in Table 1 to obtain a polymer.

[0145] Table 1 Reactant conditions, polymerization reaction conditions and polymer monomer conversion rates of examples

[0146]

[0147]

[0148] Example 18

[0149] Example 18 refers to the preparation method of Example 1, the difference is that the polymer monomer and the initiator are dissolved in an acetonitrile solution, and the addition amount of the acetonitrile solution is 1 mL.

[0150] Examples 19 to 23

[0151] Examples 19 to 23 refer to the preparation method of Example 1, except that the polymerization monomers used in Examples 19 to 23 have different structures, and the obtained polymer structures are different. Among them, the 1H NMR spectrum of the polymerization monomer used in Example 20 is as shown in Figure 2 shown.

[0152] The structural formulas of the polymerization monomers used in Examples 1 to 23 and the structural formulas of the obtained polymers are specifically shown in Table 2.

[0153] Table 2 Polymerization monomer structure and polymer structure

[0154]

[0155]

[0156] Performance test

[0157] Taking Example 1 and Example 20 as examples, the polymer finally obtained in Example 1 has the following general structural formula: wherein, n is greater than or equal to 1; the polymer obtained in Example 20 has the following general structural formula: wherein, n is greater than or equal to 1.

[0158] 1. The polymers obtained in Example 1 and Example 20 were characterized by a nuclear magnetic resonance spectrometer, and the characterization results are shown in Figure 3 and Figure 4 respectively. As shown in Figure 3 , the hydrogen spectrum characteristic peaks a, b, c of the polymer obtained in Example 1 and their respective attributions are completely consistent with the molecular structure after polymerization, indicating that the polymer synthesized by the method of the present invention has indeed undergone the process of free radical rearrangement reaction. As shown in Figure 4 , the hydrogen spectrum characteristic peaks a, b, c, d of the polymer obtained in Example 20 and their respective attributions are completely consistent with the molecular structure after polymerization, indicating that the polymer synthesized by the method of the present invention has indeed undergone the process of free radical rearrangement reaction.

[0159] 2. A thermogravimetric analysis experiment was carried out on the polymer obtained in Example 1, and the thermogravimetric curve is shown in Figure 4 . As shown in Figure 5 , the mass loss of the polymer only appears after 150 °C, indicating that the polymer structure is relatively stable and has a certain high temperature resistance.

[0160] 3. Observe the morphologies of the polymers obtained in Example 1 and Example 20. As shown in Figures 6 to 7 respectively, the polymer obtained in Example 1 presents a yellow elastic solid, and the polymer obtained in Example 20 presents a gel-like state.

[0161] 4. Measure the molecular weight, distribution width, and conversion rate of the polymerization monomer of the polymers prepared in Examples 1 to 23. The test results are shown in Table 3.

[0162] Table 3 Properties of the Polymers Obtained in Examples 1 to 23

[0163]

[0164] As can be seen from Tables 2 to 3, the polymers obtained by the polymerization reaction based on the radical rearrangement reaction of the present invention are numerous in type, rich in structure, and diverse in properties, which can meet different production requirements, have potential application value, and have a high conversion rate of the polymerization monomer, a wide range of molecular weights of the obtained polymers, a narrow distribution width, and a relatively stable structure of the polymers.

[0165] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A polymerization method based on free radical rearrangement reaction, characterized in that, It includes the following steps: Mix the polymerization monomer and the initiator, and heat the reaction to obtain a polymer; Wherein, The polymerization monomer is an olefin compound, the olefin compound contains more than 5 carbon atoms, and includes a migratable functional group and an electron-withdrawing group; The initiator includes a compound that can generate free radicals under light conditions and / or heat conditions; The polymerization monomer has the following general structural formula: Wherein, The R1 group in the polymerization monomer is a migratable reactive functional group; The R2 group in the polymerization monomer is an electron-withdrawing group; The electron-withdrawing groups in the polymerization monomer include -CN, -F, -Cl, -COOR3, -SO2Ph, -NO2, wherein R3 in -COOR3 includes an aliphatic chain; The migratable functional group includes an unsaturated functional group or a heteroatom. The unsaturated functional group includes a cyano group, an aryl group, a heteroaryl group, an oxime group, an alkenyl group, an alkynyl group or a carbonyl group. The heteroatom includes a halogen atom, silicon or boron; The polymer has the following general structural formula:

2. The polymerization method based on free radical rearrangement reaction according to claim 1, characterized in that The initiator includes at least one of an organic peroxide and an azo compound.

3. The polymerization method based on radical rearrangement reaction according to claim 2, wherein The organic peroxide includes at least one of an acyl peroxide, a hydroperoxide, a dialkyl peroxide, an ester peroxide, a ketone peroxide, a dicarbonate peroxide; And / or, the azo compound includes at least one of azodiisobutyronitrile, azodiisoheptonitrile, azodiisovaleronitrile, azodicyclohexylmethyl cyanide, dimethyl azodicarboxylate.

4. The polymerization method based on free radical rearrangement reaction according to claim 3, wherein, The acyl peroxide includes at least one of benzoyl peroxide and lauroyl peroxide; And / or, the hydroperoxide includes at least one of cumene hydroperoxide and tert-butyl hydroperoxide; And / or, the dialkyl peroxide includes at least one of di-tert-butyl peroxide and diisopropylbenzene peroxide; And / or, the ester peroxide includes at least one of tert-butyl peroxybenzoate and tert-butyl peroxy-tert-pentanoate; And / or, the ketone peroxide includes at least one of methyl ethyl ketone peroxide and cyclohexanone peroxide; And / or, the dicarbonate peroxide includes at least one of diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.

5. The polymerization method based on free radical rearrangement reaction according to claim 1, wherein The The molar ratio of the polymerization monomer to the initiator is 100:(1-20); And / or, the temperature of the heating reaction is above 35°C; And / or, the heating reaction is carried out in a protective gas atmosphere or in air. The protective gas includes nitrogen or argon; And / or, in the step of mixing the polymerization monomer and the initiator, the polymerization monomer and the initiator can also be dissolved and mixed in an organic solvent; And / or, in the step of mixing the polymerization monomer and the initiator, the polymerization monomer and the initiator are dissolved and mixed in an organic solvent. Based on the volume mL of the organic solvent, the addition amount of the polymerization monomer is (1-20) mmol / mL; And / or, in the step of mixing the polymerization monomer and the initiator, the polymerization monomer and the initiator are dissolved and mixed in an organic solvent. The organic solvent includes at least one of ethanol, acetonitrile, acetone, dimethyl sulfoxide, N,N-dimethylformamide, and ethyl acetate.

6. A polymer prepared by the polymerization method based on free radical rearrangement reaction according to any one of claims 1 to 5.

7. The polymer according to claim 6, characterized in that, The molecular weight of the polymer is above 1000; and / or, the polydispersity index (PDI) of the polymer is 1.20 - 4.00; and / or, the conversion rate of the polymerization monomer is 29% - 98%; and / or, the polymer contains acrylonitrile structural units, and the content range of acrylonitrile structural units in the polymer is 23% - 88%.

8. The polymer according to claim 7, characterized in that, The polymer has the following general structural formula: R1 in the general structural formula is a migratable functional group; R2 in the general structural formula is an electron-withdrawing group; n in the general structural formula is greater than 1; The molecular weight range of the polymer is 1000 - 100000.

9. The polymer according to claim 8, wherein the polymer has the following general structural formula (Ⅰ): In the general structural formula (I), n is greater than 1; or, the polymer has the general structural formula (Ⅱ): In the general structural formula (II), n is greater than 1; or, the polymer has the general structural formula (Ⅲ): In the general structural formula (III), n is greater than 1; or, the polymer has the general structural formula (Ⅳ): In the general structural formula (IV), n is greater than 1; or, the polymer has the general structural formula (Ⅴ): In the general structural formula (V), n is greater than 1; or, the polymer has the general structural formula (Ⅵ): In the general structural formula (VI) described above, n is greater than 1.

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