A method for efficient polymer chain end functionalization based on carbon-magnesium / carbon-zinc bond and its application

Abstract

This invention relates to a highly efficient polymer chain-end functionalization method based on carbon-magnesium / carbon-zinc bonds and its applications, belonging to the field of polymer synthesis technology. Step 1: Using living anionic polymerization, a polymer precursor with carbon-lithium or carbon-sodium bonds at the chain ends is synthesized. Step 2: Alkyl magnesium halide or alkyl zinc halide is added to the polymer precursor, causing a metal transfer reaction between the carbon-lithium or carbon-sodium bonds at the polymer precursor ends and the alkyl magnesium halide or alkyl zinc halide, yielding a polymer solution with C-Mg / C-Zn bonds at the ends. Step 3: The polymer is reacted with a specific end-capping agent to precisely introduce functional groups at the chain ends, achieving mild, efficient, and controllable end-group functionalization modification of the polymer. This invention can generate well-defined and relatively stable C-Mg or C-Zn bonds in situ at the polymer chain ends. The C-Mg / C-Zn bonds exhibit significantly enhanced resistance to air and moisture. By precisely controlling the reaction conditions and introducing a specific end-capping agent, highly efficient functionalization of the polymer chain ends can be achieved under mild conditions.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology and relates to a class of efficient polymer chain-end functionalization methods based on carbon-magnesium (C-Mg) / carbon-zinc (C-Zn) bonds and their applications. Specifically, it involves reacting an active polymer chain with alkyl magnesium halide (R1-MgX) or alkyl zinc halide (R2-ZnX) to generate in situ C-Mg or C-Zn bonds with well-defined structures and relatively stable chemical properties at the polymer chain ends. The C-Mg / C-Zn bonds exhibit significantly enhanced resistance to air and moisture. By precisely controlling the reaction conditions and introducing specific end-capping agents, efficient functionalization modification of polymer chain ends such as SBS, SIS, and SBR can be achieved under mild conditions, resulting in chain-end functionalized polymers. Background Technology

[0002] Functionalization of polymer materials is a core trend in the current development of polymer science and industry. Among numerous polymer systems, styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene rubber (SBR), and their liquid rubbers have attracted much attention due to their excellent mechanical properties, processing performance, and wide range of applications (such as adhesives, asphalt modification, plastic toughening, and sealing materials). However, these traditional polymers are mostly nonpolar or low-polar hydrocarbon materials with low surface energy and poor compatibility with polar materials (such as fillers, coatings, and polar resins), which greatly limits their further application in high-end composite materials, high-performance adhesives, and biomedical materials.

[0003] Living anionic polymerization is an important method for polymer chain-end functionalization due to the absence of chain transfer and chain termination. It typically employs alkyl lithium compounds (such as...) n -BuLi、 s Using strong nucleophiles such as alkyl magnesium (B-Li) or sodium naphthalene as initiators, the active carbon-lithium / carbon-sodium bonds at the chain ends still possess strong nucleophilic reactivity after polymerization. They can react directly with specific end-capping agents (such as ethylene oxide, carbon dioxide, silanes, etc.) to obtain functionalized polymers with polar functional groups at the ends. This is one of the most direct and effective strategies to improve their interfacial adhesion, reactivity, and compatibility with other components. However, due to the excessive reactivity of carbon-lithium / carbon-sodium bonds, their stability is poor, and they are sensitive to impurities such as trace amounts of moisture, oxygen, and carbon dioxide, easily undergoing deactivation or coupling side reactions, making industrial production difficult. Alkyl magnesium / alkyl zinc has been proven in the field of small molecule organic synthesis to efficiently construct carbon-magnesium bonds and carbon-zinc bonds with excellent stability. These carbon-metal bonds retain suitable nucleophilic reactivity and significantly improve tolerance to impurities, with reaction controllability far superior to traditional carbon-lithium / carbon-sodium bonds.

[0004] Therefore, the technical problem to be solved in this application is how to synthesize carbon-magnesium / carbon-zinc polymer chain ends with high stability, and then directionally introduce various types of functional groups such as terminal hydroxyl groups, terminal ester groups, and terminal amino groups, and develop a mild and efficient polymer chain end functionalization method. Summary of the Invention

[0005] This invention overcomes the shortcomings of traditional active anionic polymer chain-terminal carbon-lithium / carbon-sodium bonds, which are too active and have poor stability. It synthesizes carbon-magnesium / carbon-zinc polymer chain-terminals with high stability and proposes a simple, mild, universal, and highly efficient polymer chain-terminal functionalization method, achieving efficient end-group modification of various polymers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A class of efficient polymer chain-end functionalization methods based on carbon-magnesium / carbon-zinc bonds includes three steps: Step 1: Using a living anionic polymerization method, polymer precursors with carbon-lithium (C-Li) or carbon-sodium (C-Na) bonds at the chain ends are synthesized; specifically: Step 1.1, for the synthesis of homopolymers or copolymers: Under nitrogen or argon protection, monomers, organic solvents, and polarity modifiers are added to a polymerization reactor. Once the reaction solution in the reactor is heated or cooled to the polymerization temperature, an initiator is rapidly added to initiate polymerization. After the reaction, a homopolymer or copolymer reaction solution containing C-Li or C-Na bonds at the chain ends is obtained, serving as a polymer precursor.

[0007] Furthermore, the monomers added to the homopolymer are styrene-based, diene-based, acrylate-based, or vinylpyridine-based monomers, selected from styrene (St), p-methylstyrene (... p MS), p-tert-butylstyrene ( t -BS), p-tert-butoxystyrene (BOS), divinylbenzene (DVB), 1-phenyl-1,3-butadiene (1-PB), 2-phenyl-1,3-butadiene (2-PB), isoprene (Ip), butadiene (BP), methyl methacrylate (MMA), 2-vinylpyridine (2VP), 4-vinylpyridine (4VP); the copolymer contains monomers selected from St, p MS t Two or more of the following polymers are used: -BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the polymerization temperature is -20℃ to 80℃; and the reaction time is 1 to 120 hours.

[0008] Furthermore, the ratio of the total mass of added monomers to the total mass (total monomers plus organic solvents) is 1:100 to 30:100 (1~30 wt%), preferably 5:100 to 20:100 (5~20 wt%). The molar ratio of the polar additive to the initiator is 0:1 to 200:1 equivalents, preferably 5:1 to 50:1 equivalents.

[0009] Step 1.2, for the synthesis of diblock polymers: Under nitrogen or argon protection, the first monomer, organic solvent, and polarity modifier are added to the polymerization reactor. Once the reaction solution in the reactor is heated or cooled to the polymerization temperature, an initiator is added to initiate polymerization. After the reaction, a homopolymer containing C-Li or C-Na bonds at the chain ends is obtained. Then, under nitrogen or argon protection, the second monomer is added to the reaction solution, and the reaction continues to obtain a diblock polymer reaction solution containing C-Li or C-Na bonds at the chain ends, which serves as the polymer precursor.

[0010] Step 1.3, for the synthesis of triblock polymers: Under nitrogen or argon protection, the first monomer, organic solvent, and polarity modifier are added to the polymerization reactor. Once the reaction solution in the reactor is heated or cooled to the polymerization temperature, an initiator is added to initiate polymerization. After the reaction, a reaction solution containing homopolymers with C-Li or C-Na bonds at the chain ends is obtained. Then, under nitrogen or argon protection, the second monomer is added to the reaction solution. The reaction continues for 1–120 hours, and then the third monomer is added to the reaction solution again. The reaction continues for 1–120 hours, yielding a triblock polymer reaction solution with C-Li or C-Na bonds at the chain ends, which serves as the polymer precursor.

[0011] Furthermore, the first monomer is selected from St. p One of MS, t-BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the amount of polar modifier added is: polar additive / initiator = 0~200 equivalents; the polymerization temperature of the first monomer is -20℃~80℃, and the reaction time is 1~120 hours. The second monomer is selected from St, p MS t -BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the third monomer is selected from St, p MS t One of BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the first and second monomers, or the first, second, and third monomers, in the same block polymer are different from each other. The continued reaction time is 1 to 120 hours, and the continued reaction temperature is -20℃ to 80℃.

[0012] Furthermore, the ratio of the total mass of the added monomers to the total mass (the sum of the total mass of the monomers and the organic solvents) is 1:100 to 30:100 (1~30 wt%), preferably 5:100 to 20:100 (5~20 wt%). The molar ratio of the polar additive to the initiator is 0:1 to 200:1 equivalents, preferably 5:1 to 50:1 equivalents.

[0013] Step 2: Add alkyl magnesium halide (R1-MgX) or alkyl zinc halide (R2-ZnX) to the polymer precursor obtained in Step 1. This causes a metal transfer reaction between the carbon-lithium (C-Li) or carbon-sodium (C-Na) bonds at the ends of the polymer precursor and the alkyl magnesium halide (R1-MgX) or alkyl zinc halide (R2-ZnX), generating well-defined and chemically stable carbon-magnesium (C-Mg) or carbon-zinc (C-Zn) bonds in situ at the polymer chain ends, resulting in a polymer solution with C-Mg / C-Zn bonds at the ends. Specifically: Under nitrogen or argon protection, alkyl magnesium halide (R1-MgX) or alkyl zinc halide (R2-ZnX) is added to the reaction solution of homopolymers, copolymers or block copolymers containing C-Li or C-Na bonds at the chain ends. The reaction is carried out at -20℃ to 80℃ for 1 to 48 hours to obtain a polymer reaction solution containing C-Mg / C-Zn bonds at the chain ends, wherein the polymer is a homopolymer, copolymer or block copolymer.

[0014] Furthermore, the substituent R1 of the R1-MgX includes, but is not limited to, methyl, ethyl, butyl, n-butyl, sec-butyl, isopropyl, and tert-butyl, or other alkyl groups, as well as phenyl, benzyl, and naphthyl, or other aromatic groups; X includes, but is not limited to, halogen elements such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I); the substituent R2 of the R2-ZnX includes, but is not limited to, methyl, ethyl, butyl, n-butyl, sec-butyl, isopropyl, and tert-butyl, or other alkyl groups, as well as phenyl, benzyl, and naphthyl, or other aromatic groups; X includes, but is not limited to, halogen elements such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Specifically: Furthermore, the aromatic group in the aromatic group can be further functionalized by substituents, which are alkyl (methyl, ethyl and tert-butyl, etc.), alkoxy (methoxy, ethoxy, etc.), epoxy, nitro, halogen, hydroxy, amino, etc., and the substitution positions are ortho, para and meta positions of the benzene ring.

[0015] Furthermore, the molar ratio of R1-MgX or R2-ZnX to the end of the polymer active chain is 1.0:1 to 5.0:1 equivalent, that is, the molar ratio of R1-MgX or R2-ZnX to the end of the polymer active chain is 1.0:1 to 5.0:1, preferably 1.2:1 to 2.0:1 equivalent.

[0016] Step (3) Terminal functionalization reaction: The resulting polymer with C-Mg / C-Zn bonds at the ends is reacted with a specific end-capping agent to precisely introduce functional groups at the chain ends, thereby achieving mild, efficient, and controllable end-group functionalization modification of the polymer. Specifically: The polymer reaction solution containing C-Mg / C-Zn bonds at the chain ends is placed in air or a specific end-capping agent is added, wherein the molar ratio of the specific end-capping agent to the carbon-metal bonds at the polymer ends is 1.0:1 to 10.0:1. After reacting at -20℃ to 80℃ for 1 to 48 hours, degassed isopropanol is added to the reaction solution to terminate the polymerization, resulting in a gel. The gel is then dried to constant weight in a vacuum drying oven to obtain the chain-terminated functionalized polymer.

[0017] Furthermore, the specific end-capping agent is an electrophilic reagent containing oxygen, ester or acyl groups, nitrogen, or heteroatom-containing reagents, including but not limited to oxygen (air), carbon dioxide, ethylene oxide, propylene oxide, benzaldehyde, glycidyl ether, methacrylate derivatives (methyl methacrylate, glycidyl methacrylate), caprolactone, maleic anhydride, acyl chloride, vinylpyridines, aziridine, isocyanate, haloalkanes, p-toluenesulfonate, chlorosilanes, and siloxanes.

[0018] Furthermore, the molar ratio of the specific capping agent to the terminal carbon-metal bond of the polymer is 1.0:1 to 10.0:1 equivalents, preferably 1.5:1 to 3.0:1 equivalents.

[0019] Furthermore, the number-average molecular weight of the chain-terminal functionalized polymer ranges from 1.0 to 10. 3 kg / mol.

[0020] Preferably, the initiator described in this patent is selected from sodium naphthalene or alkyl lithium initiators; the lithium initiator is any initiator or mixture of several initiators disclosed in the prior art that can be used for anionic polymerization reactions, generally selected from: RLi, TRLi, or a mixture of one or more monofunctional lithium initiators, where R is a hydrocarbon group with 2 to 20 carbon atoms, R can be an alkane group or an aromatic group, and T is a metal atom or nitrogen atom, generally a metal element such as tin Sn, silicon Si, lead Pb, titanium Ti, germanium Ge, etc., preferably from: ethyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, monofunctional lithium initiators containing tin or nitrogen atoms, etc.

[0021] Preferably, the organic solvent described in this patent is selected from one or a mixture of several hydrocarbon solvents, including nonpolar aromatic hydrocarbons and nonpolar aliphatic hydrocarbons. Generally, it is selected from one or a mixture of several of the following: benzene, toluene, ethylbenzene, xylene, pentane, hexane, heptane, octane, cyclohexane, n-hexane, cyclopentane, mixed aromatic hydrocarbons (such as mixed xylenes), and mixed aliphatic hydrocarbons (such as raffinate oil). It is more preferably selected from one or a mixture of several of the following: benzene, toluene, hexane, n-hexane, cyclohexane, and cyclopentane.

[0022] Preferably, the polar additive described in this patent is selected from one or more compounds selected from oxygen-containing, nitrogen-containing, sulfur-containing, phosphorus-containing polar compounds and alkoxy metal compounds, such as: (1) oxygen-containing compounds, generally selected from: diethyl ether, tetrahydrofuran (THF), R1OCH2CH2OR2 (wherein: R1 and R2 are alkyl groups with 1 to 6 carbon atoms, R1 and R2 can be the same or different, it is preferred that R1 and R2 are different, such as: ethylene glycol dimethyl ether, ethylene glycol diethyl ether), R1OCH2CH2OCH2CH2OR2 (wherein: R1 and R2 are alkyl groups with 1 to 6 carbon atoms, R1, R2 can be the same or different, but it is preferred that R1 and R2 are different, such as: diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, crown ether; (2) nitrogen-containing compounds, generally selected from: triethylamine, tetramethylethylenediamine (TMEDA), dipiperidine ethane (DPE); (3) phosphorus-containing compounds, generally selected from hexamethylphosphoric triamine (HMPA); (4) alkoxy metal compounds, generally selected from ROM, where: R is an alkyl group with 1-6 carbon atoms, O is an oxygen atom, and M is sodium Na, potassium K or lithium Li, preferably from: potassium tert-butoxy, potassium tert-pentoxy, sodium 2,3-dimethyl-3-pentanol (NaODP).

[0023] Preferably, the alkyl magnesium halide (R1-MgX) described in this patent is preferably a mixture of one or more of the following reagents: phenyl magnesium chloride, phenyl magnesium bromide, ethyl magnesium bromide, butyl magnesium bromide, butyl magnesium chloride, cyclopropyl magnesium bromide, methyl magnesium iodide, p-methylphenyl magnesium bromide, 2-naphthyl magnesium bromide, 3,5-dimethylphenyl magnesium bromide, 3,5-dimethyl-4-methoxyphenyl magnesium bromide, benzyl magnesium bromide, and 2,4,6-trimethylphenyl magnesium bromide. The alkyl zinc halide (R2-ZnX) is preferably a mixture of one or more of the following reagents: isopropyl zinc bromide, cyclopropyl zinc bromide, ethyl zinc bromide, ethyl zinc iodide, methyl zinc chloride, and phenethyl zinc bromide.

[0024] Compared with traditional methods for functionalizing the chain ends of living anionic polymerization, the present invention has the following advantages: Traditional reactive anionic polymer chains typically end in highly reactive carbon-lithium (C-Li) or carbon-sodium (C-Na) bonds. Their end-capping reactions are extremely sensitive to water and oxygen, requiring harsh reaction conditions, making it difficult to achieve efficient functionalization of the polymer chain under mild conditions. This invention innovatively develops a class of efficient polymer chain-end functionalization methods based on carbon-magnesium (C-Mg) / carbon-zinc (C-Zn) bonds. By adding alkyl magnesium halide (R1-MgX) or alkyl zinc halide (R2-ZnX) to the polymer reaction solution, well-defined and relatively chemically stable C-Mg or C-Zn bonds can be generated in situ at the polymer chain ends. The C-Mg / C-Zn bonds exhibit significantly enhanced tolerance to air and moisture. By precisely controlling the reaction conditions and introducing specific end-capping agents, efficient functionalization of polymer chains such as SBS, SIS, and SBR can be achieved under mild conditions. In summary, the method of this invention overcomes the technical bottlenecks of traditional polymer end-functionalization processes, which are complex, demanding, inefficient, and costly. It has the outstanding advantages of mild conditions, high functionalization efficiency, diverse functional groups, and applicability to various polymer systems. It provides a new technical path for the development of high-performance functionalized polymer materials and has important theoretical significance and broad industrial application prospects. Attached Figure Description

[0025] Figure 1 These are gel permeation chromatograms of air-functionalized samples from Example 1 and Comparative Example 1. Figure 1 (a) in the figure is the gel permeation chromatogram of Example 1; Figure 1 (b) in the figure is the gel permeation chromatogram of Comparative Example 1; Figure 2 This is the matrix-assisted laser desorption / ionization time-of-flight mass spectrum of air-functionalized material in Example 1. Figure 3 The matrix-assisted laser desorption / ionization time-of-flight mass spectra of air functionalized in Comparative Example 1 are shown. Detailed Implementation

[0026] The present invention provides the following embodiments as further illustration, but these are not intended to limit the scope of protection of the claims of the present invention. The microstructure of the polymer was analyzed using nuclear magnetic resonance spectroscopy, infrared spectroscopy, and matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF). The molecular weight and molecular weight distribution index (weight-average molecular weight to number-average molecular weight) of the polymer were analyzed using gel permeation chromatography (GPC).

[0027] Example 1 (No. 1, homopolymer) Under nitrogen or argon protection, 10.0 g of St (10wt%) and 90.0 g of solvent benzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 30°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 0 equivalent) were added according to the designed molecular weight of 5.0 kg / mol. After reacting at 30°C for 3 hours, phenyl magnesium bromide (phenyl magnesium bromide: sec-butyllithium = 1.0:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 30°C for another 3 hours, the reaction solution was placed in air. After continuing the reaction at 30°C for 48 hours, the polymerization was terminated by adding degassed isopropanol. The product was precipitated in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl groups at the chain ends. The product analysis results are as follows: The GPC spectrum shows a narrow single-peak distribution (e.g., Figure 1 a) MALDI-TOF mass spectrometry shows only a cluster of regular sequence peaks (e.g.) Figure 2 The calculated number-average molecular weight was 5.0 kg / mol, the molecular weight distribution was 1.09, the yield was 96%, and the hydroxyl functionalization efficiency was 95%.

[0028] Example 2 (No. 2, homopolymer) Under nitrogen or argon protection, 15.0 g of BP (15 wt%) and 85.0 g of solvent benzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 60°C. Then, sec-butyllithium initiator was added at the designed molecular weight of 1.0 kg / mol. After reacting at 60°C for 3 hours, butyl magnesium bromide (butyl magnesium bromide: sec-butyllithium = 1.5:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 60°C for another 3 hours, the reaction solution was exposed to air. After continuing the reaction at 60°C for 24 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl groups at the chain ends. The product analysis results are as follows: number average molecular weight of 1.0 kg / mol, molecular weight distribution of 1.08, yield of 93%, and hydroxyl functionalization efficiency of 96%.

[0029] Example 3 (No. 3, homopolymer) Under nitrogen or argon protection, 20.0 g of 1-PB (20 wt%) and 80.0 g of solvent benzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 20°C. Then, sodium naphthalene initiator and THF polarity modifier (polar additive / initiator = 20 equivalents) were added according to the designed molecular weight of 60.0 kg / mol. After continuing the reaction at 20°C for 4 hours, benzyl magnesium bromide (butyl magnesium bromide: sodium naphthalene = 2.0:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 20°C for 3 hours, carbon dioxide was introduced into the reaction solution. After continuing the reaction at 20°C for 4 hours, the polymerization was terminated by adding degassed isopropanol. The product was precipitated in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with carboxyl groups at the chain ends. The product analysis results are as follows: number average molecular weight of 61 kg / mol, molecular weight distribution of 1.18, yield of 95%, and carboxyl functionalization efficiency of 90%.

[0030] Example 4 (No. 4, homopolymer) Under nitrogen or argon protection, 30.0 g Ip (30 wt%) and 70.0 g ethylbenzene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 80°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 100 equivalents) were added according to the designed molecular weight of 100.0 kg / mol. After continuing the reaction at 80°C for 8 hours, 4-methoxyphenyl magnesium chloride (4-methoxyphenyl magnesium chloride: sec-butyllithium = 3.0:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 40°C for 8 hours, maleic anhydride (maleic anhydride: sec-butyllithium = 1.0:1) was added to the reaction solution. After continuing the reaction at 80°C for 8 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with ester-terminated chains. The product analysis results are as follows: the number average molecular weight is 101 kg / mol, the molecular weight distribution is 1.21, the yield is 92%, and the ester functionalization efficiency is 93%.

[0031] Example 5 (No. 5, homopolymer) Under nitrogen or argon protection, 10.0 g of the mixture is added sequentially to the polymerization reactor. pMS (10wt%) and 90.0 g of solvent benzene were mixed thoroughly, and the reaction solution was heated to the polymerization temperature of -20°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 200 equivalents) were added according to the designed molecular weight of 200.0 kg / mol. After continuing the reaction at -20°C for 80 hours, isopropyl zinc bromide (zinc bromide: sec-butyllithium = 1.2:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at -20°C for 80 hours, 4-vinylpyridine (4-vinylpyridine: sec-butyllithium = 4.0:1) was added to the reaction solution. After continuing the reaction at -20°C for 80 hours, the polymerization was terminated by adding degassed isopropanol, precipitating in excess methanol, and drying to constant weight in a vacuum drying oven to obtain a functionalized polymer with pyridine-terminated chains. The product analysis results are as follows: the number average molecular weight is 198 kg / mol, the molecular weight distribution is 1.20, the yield is 90%, and the pyridyl functionalization efficiency is 90%.

[0032] Example 6 (No. 6, homopolymer) Under nitrogen or argon protection, 1.0 g MMA (1 wt%) and 99.0 g toluene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of -20°C. Then, sec-butyllithium initiator and TMEDA polarity modifier (polar additive / initiator = 10 equivalents) were added according to the designed molecular weight of 500.0 kg / mol. After continuing the reaction at -20°C for 24 hours, phenethyl zinc bromide (phenethyl zinc bromide:sec-butyllithium = 5.0:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at -20°C for 24 hours, ethylene oxide (ethylene oxide:sec-butyllithium = 5.0:1) was added to the reaction solution. After continuing the reaction at -20°C for 24 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl-terminated chains. The product analysis results are as follows: the number average molecular weight is 508 kg / mol, the molecular weight distribution is 1.21, the yield is 90%, and the hydroxyl functionalization efficiency is 92%.

[0033] Example 7 (No. 7, homopolymer) Under nitrogen or argon protection, 5.0 g of 2VP (5wt%) and 95.0 g of toluene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of -20°C. Then, sec-butyllithium initiator and TMEDA polarity modifier (polarity additive / initiator = 15 equivalents) were added according to the designed molecular weight of 700.0 kg / mol. After continuing the reaction at -20°C for 36 hours, cyclopropyl zinc bromide (cyclopropyl zinc bromide:sec-butyllithium = 5.0:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 0°C for 36 hours, propylene oxide (propylene oxide:sec-butyllithium = 10.0:1) was added to the reaction solution. After continuing the reaction at 25°C for 36 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl-terminated chains. The product analysis results are as follows: the number average molecular weight is 718 kg / mol, the molecular weight distribution is 1.26, the yield is 90%, and the hydroxyl functionalization efficiency is 94%.

[0034] Example 9 (No. 9, copolymer) Under nitrogen or argon protection, 5.0 g St, 5.0 g Ip (10 wt%), and 90.0 g solvent ethylbenzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 70°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 10 equivalents) were added according to the designed molecular weight of 1000.0 kg / mol. After continuing the reaction at 70°C for 120 hours, phenyl magnesium bromide (phenyl magnesium bromide: sec-butyllithium = 1.1:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 0°C for 48 hours, MMA (MMA: sec-butyllithium = 10:1) was added to the reaction solution. After continuing the reaction at 0°C for 24 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with ester-terminated chains. The product analysis results are as follows: the number average molecular weight is 1000 kg / mol, the molecular weight distribution is 1.21, the yield is 90%, and the ester functionalization efficiency is 92%.

[0035] Example 10 (No. 10, copolymer) Under nitrogen or argon protection, 4.0 g St, 6.0 g BP (10 wt%), and 90.0 g ethylbenzene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 80°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 100 equivalents) were added to the reaction solution at the designed molecular weight of 800.0 kg / mol. After continuing the reaction at 80°C for 4 hours, phenylmagnesium bromide (phenylmagnesium bromide:sec-butyllithium = 1.2:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 25°C for 4 hours, the reaction solution was exposed to air. After continuing the reaction at 25°C for 48 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl-terminated chains. The product analysis results are as follows: the number average molecular weight is 795 kg / mol, the molecular weight distribution is 1.21, the yield is 90%, and the hydroxyl functionalization efficiency is 92%.

[0036] Example 11 (No. 11, Block Polymerization) Under nitrogen or argon protection, 2.5 g of St and 90.0 g of toluene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 70°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 200 equivalents) were added according to the designed molecular weight of 15.0 kg / mol. After continuing the reaction at 70°C for 24 hours, 7.5 g of Ip was added. After continuing the reaction for 50 hours, butyl magnesium chloride (butyl magnesium chloride: sec-butyllithium = 1.5:1) was added to the reaction solution under nitrogen or argon protection. After continuing the reaction at 30°C for 5 hours, the reaction solution was exposed to air. After continuing the reaction at 25°C for 48 hours, the polymerization was terminated by adding degassed isopropanol, precipitating the polymer in excess methanol, and drying it to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl-terminated chains. The product analysis results are as follows: PS segment accounts for 18%; number average molecular weight is 15 kg / mol, molecular weight distribution is 1.19, yield is 93%, and hydroxyl functionalization efficiency is 95%.

[0037] Example 12 (No. 12, Block Polymerization) Under nitrogen or argon protection, 3 g of St and 90.0 g of toluene solvent were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 80°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 150 equivalents) were added according to the designed molecular weight of 1000.0 kg / mol. After continuing the reaction at 80°C for 24 hours, 7 g of BP was added. After continuing the reaction for 60 hours, cyclopropyl zinc bromide (cyclopropyl zinc bromide: sec-butyllithium = 1.6:1) was added to the reaction solution. After continuing the reaction at 0°C for 48 hours, 4-vinylpyridine (4-vinylpyridine: sec-butyllithium = 10:1) was added to the reaction solution. After continuing the reaction at 0°C for 48 hours, the polymerization was terminated by adding degassed isopropanol, precipitating the polymer in excess methanol, and drying it to constant weight in a vacuum drying oven to obtain a functionalized polymer with pyridine groups at the chain ends. The product analysis results are as follows: PS segment accounts for 19%; number average molecular weight is 1000 kg / mol, molecular weight distribution is 1.21, yield is 94%, and pyridyl functionalization efficiency is 96%.

[0038] Example 13 (13, Block Polymerization) Under nitrogen or argon protection, 3 g of St and 90.0 g of solvent benzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 60°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 200 equivalents) were added according to the designed molecular weight of 100.0 kg / mol. After continuing the reaction at 60°C for 3 hours, 4 g of BP was added to the reaction solution. After continuing the reaction at 60°C for 3 hours, 3 g of St was added to the reaction solution. After continuing the reaction at 60°C for 3 hours, butylmagnesium bromide (butylmagnesium bromide:sec-butyllithium = 1.5:1) was added to the reaction solution. After continuing the reaction at 35°C for 4 hours, the reaction solution was exposed to air. After continuing the reaction at 25°C for 48 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain the functionalized polymer SBS with hydroxyl-terminated chains. The product analysis results are as follows: PS segment accounts for 35%; the number average molecular weight is 98 kg / mol, the molecular weight distribution is 1.19, the yield is 93%, and the hydroxyl functionalization efficiency is 96%.

[0039] Example 14 (14, Block Polymerization) Under nitrogen or argon protection, 2 g of St and 90.0 g of solvent benzene were added sequentially to the polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 50°C. Then, sec-butyllithium initiator and THF polarity modifier (polar additive / initiator = 200 equivalents) were added according to the designed molecular weight of 150.0 kg / mol. After continuing the reaction at 50°C for 3 hours, 6 g of Ip was added to the reaction solution. After continuing the reaction at 60°C for 3 hours, 2 g of St was added to the reaction solution. After continuing the reaction at 60°C for 3 hours, phenyl magnesium bromide (phenyl magnesium bromide: sec-butyllithium = 1.5:1) was added to the reaction solution. After continuing the reaction at 20°C for 6 hours, the reaction solution was exposed to air. After continuing the reaction at 20°C for 48 hours, the polymerization was terminated by adding degassed isopropanol. The precipitate was collected in excess methanol and dried to constant weight in a vacuum drying oven to obtain the functionalized polymer SIS with hydroxyl-terminated chains. The product analysis results are as follows: PS segment accounts for 25%; the number average molecular weight is 151 kg / mol, the molecular weight distribution is 1.18, the yield is 93%, and the hydroxyl functionalization efficiency is 93%.

[0040] Comparative Example 1 (compared to Implementation Example 1) Under nitrogen or argon protection, 10.0 g of St (10 wt%) and 90.0 g of solvent benzene were added sequentially to a polymerization reactor. The mixture was stirred until homogeneous, and the reaction solution was heated to the polymerization temperature of 30°C. Then, sec-butyllithium initiator was added according to the designed molecular weight of 5.0 kg / mol. After reacting at 30°C for 3 hours, the reaction solution was exposed to air. The polymerization was terminated by adding degassed isopropanol after continuing the reaction at 30°C for 48 hours. The product was precipitated in excess methanol and dried to constant weight in a vacuum drying oven to obtain a functionalized polymer with hydroxyl groups at the chain ends. The product analysis results are as follows: number average molecular weight of 5.1 kg / mol, molecular weight distribution of 1.29, and hydroxyl functionalization efficiency of 55%.

[0041] The only difference between Comparative Example 1 and Example 1 is that magnesium phenyl bromide was not added for the metal transfer reaction, and the polymer chain solution still ends in carbon-lithium (C-Li). The polymer chain solution of Comparative Example 1 was directly placed in air for the end-capping reaction, as follows... Figure 1As shown in b, the GPC spectrum of Comparative Example 1 exhibits a bimodal distribution with obvious coupling peaks and a broad molecular weight distribution. Furthermore, the MALDI-TOF spectrum shows a series of peaks with two clusters of different end-group structures. Analysis revealed one cluster to be hydroxyl-functionalized PS and the other to be unfunctionalized PS. The calculated hydroxyl functionalization efficiency of Comparative Example 1 is 55%, significantly lower than the hydroxyl functionalization efficiency (95%) in Example 1. This indicates that the efficient polymer chain-end functionalization method based on carbon-magnesium (C-Mg) / carbon-zinc (C-Zn) bonds proposed in this invention has advantages such as high functionalization efficiency and few side reactions. It can efficiently prepare functionalized polymers with high-purity end-groups, providing an excellent macromolecular platform for subsequent functionalization modification and high-performance material preparation, and possesses outstanding potential for industrial application.

[0042] The above-described embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A class of efficient polymer chain-end functionalization methods based on carbon-magnesium / carbon-zinc bonds, characterized in that, Includes the following steps: Step 1: Using a living anionic polymerization method, polymer precursors with carbon-lithium (C-Li) or carbon-sodium (C-Na) bonds at the chain ends are synthesized; Step 2: Under nitrogen or argon protection, add alkyl magnesium halide R1-MgX or alkyl zinc halide R2-ZnX to the polymer precursor obtained in Step 1. React at -20℃ to 80℃ for 1 to 48 hours to allow the carbon-lithium or carbon-sodium bonds at the ends of the polymer precursor to undergo a metal transfer reaction with the alkyl magnesium halide or alkyl zinc halide, generating well-defined and chemically stable carbon-magnesium or carbon-zinc bonds in situ at the polymer chain ends, resulting in a polymer solution with C-Mg / C-Zn bonds at the ends; wherein the polymer is a homopolymer, copolymer, or block copolymer. The molar ratio of R1-MgX to the active polymer chain end is 1.0:1 to 5.0:1; the molar ratio of R2-ZnX to the active polymer chain end is 1.0:1 to 5.0:

1. Step 3, end-functionalization reaction: The obtained polymer with C-Mg / C-Zn bonds at the end is reacted with a specific end-capping agent to precisely introduce functional groups at the chain end, thereby achieving mild, efficient and controllable end-group functionalization modification of the polymer.

2. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 1, characterized in that, Step 1 specifically involves: Step 1.1, for the synthesis of homopolymers or copolymers: under nitrogen or argon protection, monomers, organic solvents, and polarity modifiers are added to the polymerization reactor; after the reaction liquid in the polymerization reactor is heated or cooled to the polymerization temperature, an initiator is quickly added to initiate polymerization. After the reaction, a homopolymer or copolymer reaction liquid with C-Li or C-Na bonds at the chain ends is obtained as a polymer precursor. Step 1.2, for the synthesis of diblock polymers: Under nitrogen or argon protection, the first monomer, organic solvent, and polarity modifier are added to the polymerization reactor; after the reaction solution in the polymerization reactor is heated or cooled to the polymerization temperature, an initiator is added to initiate polymerization, and the reaction solution yields a homopolymer containing C-Li or C-Na bonds at the chain ends; then, under nitrogen or argon protection, the second monomer is added to the reaction solution, and the reaction continues to obtain a diblock polymer reaction solution containing C-Li or C-Na bonds at the chain ends, which serves as the polymer precursor; Step 1.3, for the synthesis of triblock polymers: Under nitrogen or argon protection, the first monomer, organic solvent, and polarity modifier are added to the polymerization reactor; after the reaction solution in the polymerization reactor is heated or cooled to the polymerization temperature, an initiator is added to initiate polymerization, and a reaction solution containing C-Li or C-Na bonds at the chain ends is obtained; then, under nitrogen or argon protection, the second monomer is added to the reaction solution; the reaction continues for 1 to 120 hours, and the third monomer is added to the reaction solution again; the reaction continues for 1 to 120 hours, and a triblock polymer reaction solution containing C-Li or C-Na bonds at the chain ends is obtained, which serves as the polymer precursor; The monomers used in the above steps are styrene-based, diene-based, acrylate-based, or vinylpyridine-based monomers.

3. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 2, characterized in that, In step 1: In step 1.1, the monomers added to the homopolymer are selected from styrene (St) and p-methylstyrene. p MS, p-tert-butylstyrene t -BS, p-tert-butoxystyrene BOS, divinylbenzene DVB, 1-phenyl-1,3-butadiene 1-PB, 2-phenyl-1,3-butadiene 2-PB, isoprene Ip, butadiene BP, methyl methacrylate MMA, 2-vinylpyridine 2VP, 4-vinylpyridine 4VP; the copolymer contains monomers selected from St, p MS t Two or more of the following polymers are used: -BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the polymerization temperature is -20℃ to 80℃; and the reaction time is 1 to 120 hours. In step 1.1, the total mass of added monomers is in a mass ratio of 1:100 to 30:100, preferably 5:100 to 20:100 (5~20wt%); the molar ratio of the polar additive to the initiator is 0:1 to 200:1 equivalents, preferably 5:1 to 50:1 equivalents; the total mass refers to the sum of the total monomers and the organic solvent. In step 1.2, the first monomer is selected from St, p MS, t-BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP are selected from the following: the polymerization temperature of the first monomer is -20℃ to 80℃, and the reaction time is 1 to 120 hours; the second monomer is selected from St, p MS t -BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP, and 4VP; the third monomer is selected from St, p MS t - One of BS, BOS, DVB, 1-PB, 2-PB, Ip, BP, MMA, 2VP and 4VP; the first and second or the first, second and third monomers in the same block polymer are different; the reaction time is 1 to 120 hours and the reaction temperature is -20℃ to 80℃; In step 1.2, the total mass of the added monomers is in a mass ratio of 1:100 to 30:100; the molar ratio of the polar additive to the initiator is 0:1 to 200:1 equivalent; the total mass refers to the sum of the total mass of the monomers and the organic solvent.

4. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 3, characterized in that, In step 1: In step 1.1, the total mass of added monomers is in a mass ratio of 5:100 to 20:100; the molar ratio of the polar additive to the initiator is in an equivalent ratio of 5:1 to 50:

1. In step 1.2, the total mass of added monomers is in a mass ratio of 5:100 to 20:100 (5~20wt%); the molar ratio of the polar additive to the initiator is 5:1 to 50:1 equivalent.

5. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 4, characterized in that, In step 2: The R1-MgX substituent R1 is selected from methyl, ethyl, butyl, n-butyl, sec-butyl, isopropyl, tert-butyl or other alkyl groups, as well as phenyl, benzyl, naphthyl or other aromatic groups; X is selected from fluorine, chlorine, bromine or iodine; The substituent R2 in R2-ZnX is selected from methyl, ethyl, butyl, n-butyl, sec-butyl, isopropyl, tert-butyl or other alkyl groups, as well as phenyl, benzyl, naphthyl or other aromatic groups; X is selected from fluorine, chlorine, bromine or iodine. The molar ratio of R1-MgX to the active chain end of the polymer is 1.2:1 to 2.0:1; the molar ratio of R2-ZnX to the active chain end of the polymer is 1.2:1 to 2.0:

1.

6. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 5, characterized in that, In step 2: The aromatic group in the aromatic group can be further functionalized by substituents, which are alkyl, alkoxy, epoxy, nitro, halogen, hydroxyl or amino, and the substitution positions are ortho, para or meta of the benzene ring.

7. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 6, characterized in that, Step 3 specifically involves: placing the polymer reaction solution containing C-Mg / C-Zn bonds at the chain ends in air or adding a specific end-capping agent, wherein the molar ratio of the specific end-capping agent to the carbon-metal bonds at the polymer ends is 1.0:1 to 10.0:1; reacting at -20℃ to 80℃ for 1 to 48 hours, then adding degassed isopropanol to the reaction solution to terminate the polymerization, precipitating the polymer, and drying it to constant weight in a vacuum drying oven to obtain the chain-terminated functionalized polymer.

8. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 7, characterized in that, In step 3: The specific end-capping agents are oxygen-containing, ester-containing or acyl-containing, nitrogen-containing electrophilic reagents and silicon / tin heteroatom-containing reagents; The molar ratio of the specific capping agent to the terminal carbon-metal bond of the polymer is 1.0:1 to 10.0:1 equivalent; The number-average molecular weight of the end-functionalized polymer is in the range of 1.0 to 10. 3 kg / mol.

9. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 8, characterized in that, In step 3: The specific end-capping agent is selected from oxygen, air, carbon dioxide, ethylene oxide, propylene oxide, benzaldehyde, glycidyl ether, methacrylate derivatives, caprolactone, maleic anhydride, acyl chloride, vinylpyridine, aziridine, isocyanate, haloalkanes, p-toluenesulfonate, chlorosilane, and siloxane. The molar ratio of the specific capping agent to the terminal carbon-metal bond of the polymer is 1.5:1 to 3.0:1 equivalent.

10. The method for efficient polymer chain-end functionalization based on carbon-magnesium / carbon-zinc bonds according to claim 9, characterized in that, In the method: The initiator is selected from sodium naphthalene or alkyl lithium initiators; The organic solvent is selected from one type of hydrocarbon solvent or a mixture of several types of hydrocarbon solvents, including nonpolar aromatic hydrocarbons and nonpolar aliphatic hydrocarbons. The polar additive is selected from one or a mixture of several compounds, including oxygen-containing, nitrogen-containing, sulfur-containing, phosphorus-containing polar compounds and alkoxy metal compounds.

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