A main-chain polymer, and a preparation method and application thereof

Abstract

The application relates to a main chain polymer and a preparation method and application thereof, and belongs to the technical field of polymer synthesis. The preparation method of the main chain polymer is a sulfur radical reversible addition fragmentation chain transfer polymerization method, main reaction raw materials include an allyl sulfur chain transfer agent, an allyl sulfur macrocycle monomer and an initiator, and specifically include the following five stages: chain initiation, chain transfer to a chain transfer agent, reinitiation, chain growth and chain termination. The method can directly realize the regulation of a sulfur radical chain growth polymerization reaction, so that a main chain polymer with a structure of a functional group R3 in a polymer main chain is obtained, and the polymer molecular weight has a linear relationship with a monomer conversion rate, which meets the characteristics of a controllable polymerization reaction. Since the polymer terminal end retains a relatively complete allyl sulfur structure, the polymer can be further used for the synthesis of a block copolymer and other main chain polymers.

Description

Technical Field

[0001] This invention relates to the technical field of polymer synthesis, specifically to a main-chain polymer, its preparation method, and its applications. Background Technology

[0002] Controlled radical polymerization (CRPM) has been widely applied in polymer science due to its mild conditions and good functional group compatibility. However, current CRPM tools are mainly limited to controlling alkyl radicals, and remain unable to control sulfur radicals, thus severely limiting the range of monomers for CRPM and their application in the synthesis of main-chain functional polymers. To address this issue, early researchers primarily used radical copolymerization, where alkene monomers capture chain-growing sulfur radicals during polymerization to generate controllable alkyl radicals, achieving controlled radical copolymerization (J. Am. Chem. Soc. 2009, 131, 9805-9812.). The reaction process is as follows:

[0003]

[0004] Until 2023, Professor Huang Hanchu's research group at Sun Yat-sen University, through a free radical desulfurization strategy, utilized isonitriles to convert sulfur free radicals into controllable alkyl free radicals on-site during the polymerization process, thus directly realizing the controlled free radical polymerization reaction of this type of monomer (Angew. Chem. Int. Ed. 2023, 62, e2023085.). The reaction process is as follows:

[0005]

[0006] However, both radical copolymerization and radical desulfurization strategies currently have relatively low overall efficiency. For example, radical copolymerization often suffers from low sulfur radical monomer incorporation, while radical desulfurization requires the use of excessive isonitriles, and desulfurization also makes the polymerization reaction lack atom economy. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a main-chain polymer, its preparation method, and its applications. The main-chain polymer is prepared using a sulfur radical reversible addition-fragmentation chain transfer polymerization (SRAFT) method. Specifically, by controlling the chain-growing sulfur radicals through an allyl sulfur chain transfer agent, the controlled radical ring-opening polymerization of the allyl sulfur macrocyclic monomer is achieved, resulting in a main-chain polymer with controllable molecular weight and a narrow molecular weight distribution. This polymerization reaction follows first-order kinetics, and the polymer molecular weight is linearly related to the monomer conversion rate. The terminal allyl sulfur structure of the polymer is relatively intact, allowing for further use in the synthesis of block copolymers and other main-chain polymers.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a main-chain polymer, the main-chain polymer having the following general structural formula:

[0010]

[0011] Among them, R 1 C 12 H 25 S or MeO2CCH2, R 2 for t At least one of BuO2C, methoxyphenyl, phenyl, carboxyphenyl, and hydrogen, R 3 Groups with any of the following structures:

[0012] --- indicates the replacement position.

[0013] The main-chain polymer has the functional group R. 3 The main chain polymer has a structure with an allyl sulfide structure at the polymer end, and the functional groups are highly compatible, which can effectively improve the applicability of the main chain polymer.

[0014] Preferably, the main chain polymer has a structure of P1, P2, or P3;

[0015]

[0016] Preferably, the main chain polymer has a number-average molecular weight of (0.5-3) thousand and a molecular weight distribution coefficient of 1.2-1.5.

[0017] Secondly, the present invention provides a method for preparing a main-chain polymer, comprising the following steps: mixing an allyl sulfide chain transfer agent as shown in formula (I), an allyl sulfide macrocyclic monomer as shown in formula (II), an initiator, and an organic solvent, and reacting to obtain a main-chain polymer as shown in formula (III), wherein the general reaction formula is as follows:

[0018]

[0019] The structure of the allyl sulfide chain transfer agent I is selected from any of the following:

[0020]

[0021] The structure of the allyl thio macrocyclic monomer II is selected from any of the following:

[0022]

[0023] The specific reaction mechanism of the above preparation method includes the following five stages:

[0024] (1) Chain triggering:

[0025]

[0026] (2) Chain transfer to chain transfer agent:

[0027]

[0028] (3) Re-triggering:

[0029]

[0030] (4) Chain growth:

[0031]

[0032] (5) Chain termination:

[0033]

[0034] This invention employs a reversible addition-fragmentation chain transfer polymerization method using sulfur radicals. This invention can polymerize functional groups R... 3 By incorporating allyl sulfide compounds as chain transfer agents onto the polymer backbone, controlled radical ring-opening polymerization of allyl sulfide macrocyclic monomers can be achieved, yielding a main-chain polymer with controllable molecular weight and a narrow molecular weight distribution. This polymerization reaction follows first-order kinetics, and the polymer molecular weight exhibits a linear relationship with monomer conversion. The polymerization reaction demonstrates a certain degree of atom economy, which can further promote the application of controlled radical polymerization in the field of polymer science.

[0035] Specifically, when CTA5 was selected as the chain transfer agent, the conversion rate was the highest, but the actual molecular weight distribution coefficient of the polymer was relatively large. When CTA6 was selected, the conversion rate was the lowest, but the actual molecular weight distribution coefficient of the polymer was also relatively large. Experiments showed that the polymerization reaction could be well controlled when CTA3 was used as the chain transfer agent, producing a polymer with a number average molecular weight of 11,900 and a molecular weight distribution coefficient of 1.29, and the molecular weight was relatively close to the theoretical molecular weight.

[0036] Preferably, the reaction conditions are: a temperature of 60–80°C and a protective atmosphere for 10–20 hours. More preferably, the reaction is carried out at 70°C and under nitrogen atmosphere for 15 hours.

[0037] Preferably, the initiator is azobisisobutyronitrile (AIBN) initiator.

[0038] Preferably, the molar ratio of the allyl sulfide macrocyclic monomer II to the allyl sulfide chain transfer agent I is (10-100):1. By controlling the molar ratio of the allyl sulfide macrocyclic monomer to the allyl sulfide chain transfer agent, the polymerization reaction of the present invention can obtain polymers with different molecular weights and narrow distributions. The above polymerization reaction follows first-order kinetics, and the polymer molecular weight increases with increasing monomer conversion rate. When the molar ratio of the allyl sulfide macrocyclic monomer to the allyl sulfide chain transfer agent is 10:1, the polymer with the lowest number-average molecular weight is obtained. When the molar ratio of the allyl sulfide macrocyclic monomer to the allyl sulfide chain transfer agent is 100:1, the polymer with the highest number-average molecular weight is obtained.

[0039] Preferably, the molar ratio of the allyl sulfide chain transfer agent I to the initiator is (1-3):1. More preferably, it is 2:1.

[0040] Preferably, the allyl thiomacyclomonomer is mixed with the organic solvent to form a solution, wherein the molar concentration of the allyl thiomacyclomonomer in the solution is 0.05–0.2 M, more preferably 0.1 M.

[0041] Preferably, the organic solvent is at least one selected from N,N-dimethylformamide (DMF), tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), 1,4-dioxane, and toluene. DMF is the most preferred solvent, followed by THF. However, when toluene is used as a solvent, the reaction effect is relatively poor, possibly due to the poor solubility of the polymer in toluene.

[0042] Thirdly, the present invention provides an application of the method for preparing the main-chain polymer in the preparation of block copolymers or polymers whose main chain contains ester group sequences.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] (1) The method for preparing the main-chain polymer provided by this invention is a sulfur radical reversible addition-fragmentation chain transfer polymerization method. The main reactants include an allyl sulfur chain transfer agent, an allyl sulfur macrocyclic monomer, and an initiator. Specifically, it includes the following five stages: chain initiation, chain transfer to the chain transfer agent, re-initiation, chain growth, and chain termination. This method can directly control the sulfur radical chain growth polymerization reaction, thereby obtaining polymers with functional groups R. 3 In the main chain structure of polymers, traditional controlled radical polymerization reactions can generally only produce R... 3 This method leads to the side chains of the polymer, and is simpler and more efficient.

[0045] (2) The preparation method of the present invention can synthesize main-chain polymers with different molecular weights and narrow molecular weight distributions by adjusting the ratio of allyl sulfide chain transfer agent to allyl sulfide macrocyclic monomer. This is because the synthesized main-chain polymers have allyl sulfide structures at their chain ends. This structure remains that of a chain transfer agent, and therefore can be used as a macromolecular chain transfer agent containing polymer fragments to extend the chain of another monomer to synthesize block copolymers. This invention overcomes the limitation of traditional controlled radical polymerization reactions in synthesizing sulfur radical chain-grown block copolymers, thus broadening the applicability of the monomer.

[0046] (3) This invention synthesizes fragments containing ester functional sequences onto the ring chains of macrocyclic monomers in only two steps (as shown in the M3 structure). Then, using the preparation method of this invention, this fragment containing ester functional sequences can be incorporated into the polymer backbone (as shown in the P3 structure). The entire process is simple, and the raw materials are readily available. Although traditional stepwise polymerization methods can also synthesize polymers with ester functional sequences in the backbone, due to the limitations of the methods themselves, the resulting polymers typically have a large molecular weight distribution coefficient (>1.5). In contrast, the preparation method of this invention can produce polymers with well-defined molecular weights and small molecular weight distribution coefficients (>1.5). ( ) Polymers whose main chain contains ester functional sequences. Attached Figure Description

[0047] Figure 1 GPC curves for the polymerization of monomer M1 under different chain transfer agent conditions.

[0048] Figure 2 The graphs show the GPC curves of monomer M1 under different solvent conditions.

[0049] Figure 3 This is a GPC curve of monomer M1 under different monomer-to-chain transfer agent ratios.

[0050] Figure 4 This is a GPC curve of monomer M2 under different monomer and chain transfer agent ratios.

[0051] Figure 5 This is a graph showing the relationship between monomer conversion and reaction time in the M1 polymerization reaction.

[0052] Figure 6 This is a graph showing the relationship between the polymer molecular weight and monomer conversion rate in the M1 polymerization reaction.

[0053] Figure 7 GPC curves for preparing block copolymer P1-b-P2.

[0054] Figure 8The 1H NMR spectrum of the block copolymer P1-b-P2 is shown.

[0055] Figure 9 The 1H NMR spectra of chain transfer agents CTA1-CTA6 are shown.

[0056] Figure 10 The NMR spectra of monomers M1-M3 are 1H NMR spectra.

[0057] Figure 11 The NMR spectra of polymers P1-P3 are shown in the form of 1H NMR. Detailed Implementation

[0058] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0059] This invention provides a method for preparing a main-chain polymer, comprising the following steps: mixing an allyl sulfide chain transfer agent as shown in formula (I), an allyl sulfide macrocyclic monomer as shown in formula (II), an initiator, and an organic solvent, and reacting to obtain a main-chain polymer as shown in formula (III), the general reaction formula being as follows:

[0060]

[0061] I. Preparation of Allyl Sulfide Chain Transfer Agents

[0062] This embodiment provides a method for preparing an allyl sulfide chain transfer agent. The specific synthesis method is as follows: Bromopropylene A (1.0 equiv.), thiol B (1.2 equiv.), anhydrous potassium carbonate (1.5 equiv.), and DMF (50 mL) are added to a 150 mL round-bottom flask. After reacting at room temperature for 24 h, the reaction solution is diluted with 1 M hydrochloric acid solution (30 mL), followed by extraction with ethyl acetate (3 × 30 mL). The organic phases are combined, washed with saturated brine, dried over anhydrous sodium sulfate, concentrated under vacuum, and subjected to column chromatography to obtain chain transfer agent C. The general rules for the synthesis of chain transfer agents are as follows:

[0063]

[0064] 1.1 Synthesis of tert-butyl acrylate (CTA1) of 2-[(2-methoxy-2-oxoethyl)thiomethyl]acrylate

[0065] Following the above method for preparing chain transfer agents, a colorless oily liquid CTA1 (1.44 g, 45% yield) was prepared from tert-butyl 2-(bromomethyl)acrylate (3.00 g, 13.6 mmol) and methyl mercaptoacetate (1.73 g, 16.3 mmol). The structural formula of compound CTA1 is shown below. NMR characterization results: 1H NMR (400MHz, CDCl3) δ6.15(d,J=1.5Hz,1H),5.60(q,J=1.1Hz,1H),3.73(s,3H),3.46(d,J=1.0Hz,2H),3.16(s,2H),1.50(s,9H). 13 CNMR (100MHz, CDCl3) δ171.0,165.2,137.5,125.9,81.4,52.5,33.2,32.4,28.2.

[0066]

[0067] 1.2 Synthesis of tert-butyl 2-(dodecylthiomethyl)acrylate CTA2

[0068] Following the above method for preparing chain transfer agents, a colorless oily liquid CTA2 (2.93 g, 63% yield) was prepared from tert-butyl 2-(bromomethyl)acrylate (3.00 g, 13.6 mmol) and dodecyl mercaptan (3.9 mL, 16.3 mmol). The structural formula of compound CTA2 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3) δ6.09 (d, J = 1.6Hz, 1H), 5.60-5.53 (m, 1H), 3.33 (s, 2H), 2.44 (t,J=7.5Hz,2H),1.64-1.45(m,12H),1.35-1.20(m,18H),0.88(t,J=6.8Hz,3H). 13 C NMR (100MHz, CDCl3) δ165.7,138.9,124.7,81.2,33.0,32.1,31.8,29.8,29.8,29.7,29.7,29.5,29.5,29.4,29.1,28.2,22.8,14.3.

[0069]

[0070] Synthesis of 1,3-(2-phenylallyl)dodecyl sulfide CTA3

[0071] Following the above method for preparing chain transfer agents, a colorless oily liquid CTA3 (3.50 g, 55% yield) was prepared from (1-bromomethyl-vinyl)benzene (3.94 g, 20.0 mmol) and dodecyl mercaptan (5.8 mL, 24.0 mmol). The structural formula of compound CTA3 is shown below. NMR characterization results: 1H NMR (400MHz, CDCl3) δ7.49 (d, J = 7.1Hz, 2H), 7.38-7.23 (m, 3H), 5.44 (s, 1H), 5.22 (s, 1H), 3.60 ( s,2H),2.48(t,J=7.4Hz,2H),1.58(p,J=7.1Hz,2H),1.41-1.22(m,18H),0.90(t,J=6.8Hz,3H). 13 C NMR (100MHz, CDCl3) δ144.0,139.7,128.4,127.9,126.4,114.8,36.7,32.1,31.6,29.8,29.8,29.7,29.7,29.5,29.4,29.4,29.1,22.8,14.2.

[0072]

[0073] 1.4 Synthesis of [2-(4-methoxyphenyl)allyl]dodecyl sulfide CTA4

[0074] Following the above-described method for preparing chain transfer agents, a colorless oily liquid CTA4 (0.3 g, 51% yield) was prepared from (1-bromomethyl-vinyl)-4-anisole (0.39 g, 1.7 mmol) and dodecyl mercaptan (0.48 mL, 2.04 mmol). The structural formula of compound CTA4 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3) δ7.42(d,J=8.8Hz,2H),6.88(d,J=8.7Hz,2H),5.36(s,1H),5.11(s,1H),3.81(s, 3H), 3.56 (s, 2H), 2.45 (t, J = 7.4Hz, 2H), 1.60-1.50 (m, 3H), 1.38-1.19 (m, 18H), 0.88 (t, J = 6.7Hz, 3H). 13 C NMR (100MHz, CDCl3): δ159.5,143.2,127.6,126.3,113.8,113.3,55.4,36 .8,32.1,31.6,29.8,29.8,29.8,29.7,29.5,29.4,29.4,29.1,22.8,14.3.

[0075]

[0076] Synthesis of 1,5-[2-(4-methoxycarbonylphenyl)allyl]dodecyl sulfide CTA5

[0077] Following the above-described method for preparing chain transfer agents, methyl 4-(2-bromoacetyl)benzoate (2.18 g, 8.5 mmol) and dodecyl mercaptan (2.3 mL, 9.7 mmol) were reacted with a Wittig reaction to yield a colorless oily liquid, CTA5 (0.4 g, 15% yield). The structural formula of compound CTA5 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3): δ8.01(d,J=8.5Hz,2H),7.53(d,J=8.5Hz,2H),5.51(s,1H),5.29(s,1H),3.91(s, 3H), 3.59 (s, 2H), 2.45 (t, J = 7.4Hz, 2H), 1.60-1.49 (m, 2H), 1.37-1.20 (m, 18H), 0.88 (t, J = 6.7Hz, 3H). 13 CNMR (100MHz, CDCl3): δ167.0,144.2,143.3,129.8,129.5,126.5,116.6,52.2 ,36.5,32.1,31.6,29.8,29.8,29.7,29.7,29.5,29.4,29.3,29.1,22.8,14.3.

[0078]

[0079] Synthesis of 1,6-Dodecyl Allyl Sulfide (CTA6)

[0080] Following the above-described method for preparing chain transfer agents, a colorless oily liquid CTA6 (2.80 g, 70% yield) was prepared from allyl bromide (2.00 g, 16.5 mmol) and dodecyl mercaptan (3.68 g, 18.2 mmol). The structural formula of compound CTA6 is shown below. NMR characterization results: 1 H NMR(400MHz, CDCl3)δ5.79(td,J=17.2,7.2Hz,1H),5.20-4.99(m,2H),3.12(d,J=7.1Hz, 2H), 2.45(t,J=7.4Hz,2H),1.64-1.50(m,2H),1.39-1.19(m,18H),0.88(t,J=6.6Hz,3H). 13 C NMR (100MHz, CDCl3) δ134.8,116.8,34.9,32.1,30.9,29.8,29.8,29.8,29.7,29.5,29.4,29.1,22.8,14.3.

[0081]

[0082] II. Preparation of allyl thiomacrocyclic monomers

[0083] This embodiment provides a method for preparing an allyl thiomacrocyclic monomer (referencing the researcher's patent ZL2022102620018). The specific synthesis method is as follows: D (1.0 equiv.) and DCM (30 mL) are added to a 150 mL round-bottom flask, followed by the addition of Boc-protected aminocarboxylic acid E (1.5 equiv.), 1-ethyl-(3-dimethylaminopropyl)carbonate diimine hydrochloride (1.5 equiv.), and 4-dimethylaminopyridine (0.05 equiv.). After reacting at room temperature for 14 h, the reaction solution is diluted with DCM (100 mL), followed by washing with 1 M hydrochloric acid (50 mL) and saturated brine, drying with anhydrous MgSO4, and purification by column chromatography to obtain an intermediate compound. This intermediate compound (1.0 equiv.) is then dissolved in DCM (30 mL), and triethylsilane (10.0 equiv.) and trifluoroacetic acid (13.0 equiv.) are added, and the reaction is carried out at room temperature for 2 h. Toluene (30 mL) was added, and the solvent was removed by vacuum rotary evaporation to obtain a colorless, transparent oily liquid. This oily liquid was then dissolved in DMF (1000 mL), and 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate (2.0 equiv.) was added. After stirring at room temperature for 2 h, N,N-diisopropylethylamine (5.0 equiv.) was added, and the reaction was continued for 36 h. DMF was removed by vacuum rotary evaporation, and ethyl acetate (100 mL) was added. The mixture was washed with 1 M hydrochloric acid (3 × 50 mL), 0.5 M sodium hydroxide solution (2 × 50 mL), and saturated brine (50 mL), respectively. The mixture was dried over anhydrous MgSO4, purified by column chromatography, and characterized by NMR. The general rules for the synthesis of the above allyl thio macrocyclic monomer are as follows:

[0084]

[0085] 2.1 Preparation of allyl thiomacrocyclic monomer M1

[0086] Following the method described above for preparing macrocyclic monomeric compounds, starting from compound D (5.21 g, 10 mmol) and Boc-6-hexane (3.47 g, 15 mmol), a white solid M1 (2.20 g, 47% yield) was prepared. The structural formula of compound M1 is shown below. NMR characterization results: 1H NMR (400MHz, CDCl3) δ7.92 (d, J = 7.9Hz, 1H), 7.64-7.43 (m, 3H), 6.18 (s, 1H), 5 .74-5.48(m,3H),5.19-5.07(m,2H),4.18(t,J=7.2Hz,2H),3.89(d,J=3.7Hz, 2H),3.83(s,2H),3.45(q,J=6.3Hz,2H),3.13(d,J=5.3Hz,2H),2.67(t,J=7.2 Hz,2H),2.38(t,J=6.6Hz,2H),1.78-1.59(m,4H),1.51(p,J=6.5,5.7Hz,2H). 13 C NMR (100MHz, CDCl3): δ173.5,168.2,137.6,136.7,132.8,132.6,130.0,129.8,129 .8,129.2,128.8,119.4,64.1,49.7,47.8,40.1,34.0,33.5,28.6,28.2,25.8,24.3.

[0087]

[0088] 2.2 Preparation of allyl thiomacrocyclic monomer M2

[0089] Following the method described above for preparing macrocyclic monomeric compounds, starting from compound D (2.61 g, 5.0 mmol) and Boc-11-undecanoic acid (2.26 g, 7.5 mmol), a white solid M2 (1.17 g, 44% yield) was prepared. The structural formula of compound M2 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3): δ7.95(d,J=7.9Hz,1H),7.67-7.46(m,3H),6.22(s,1H),5.73-5.49(m,3H),5.22-5.08(m,2H),4.21(t,J=6.9Hz,2H),3.83(dd ,J=12.4,4.2Hz,4H),3.43(q,J=6.6Hz,2H),3.23-3.09(m,2H),2.67(t,J= 6.9Hz,2H),2.33(t,J=7.3Hz,2H),1.71-1.57(m,4H),1.45-1.25(m,12H). 13C NMR (100MHz, CDCl3): δ173.7,167.9,137.2,136.7,132.8,132.7,131.0,130.1,129.7,129.5,1 28.4,119.5,64.0,49.2,48.1,40.4,34.3,33.7,28.8,28.7,28.6,28.6,28.5,28.4,26.3,24.9.

[0090]

[0091] 2.3 Preparation of allyl thiomacrocyclic monomer M3

[0092] Following the above method for preparing macrocyclic monomeric compounds, a yellow oily compound M3 (1.91 g, 40% yield) was prepared from compound D (4.38 g, 8.4 mmol) and Boc-protected aminocarboxylic acid (4.20 g, 12.6 mmol). The structural formula of compound M3 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3): δ7.94(d,J=7.8Hz,1H),7.70-7.44(m,3H),6.47(s,1H),5.81-5.43(m,3H),5.29-5.06(m,2H),4.66(s,2H), 4.25(t,J=6.9Hz,4H),3.93-3.71(m,4H),3.51(q,J=6.4Hz,2H),3.13(d,J=5.5Hz,2H),2.83-2.55(m,6H),1.96(p,J=6.1Hz,2H). 13 C NMR (100MHz, CDCl3): δ172.1,171.7,168.0,167.5,137.2,136.5,132.9,132.7,130.8,130.1, 129.8,129.4,128.3,119.5,64.9,62.1,61.2,49.3,47.7,37.1,33.7,29.5,29.1,28.5,28.4.

[0093]

[0094] Examples 1-2

[0095] The preparation method of the main-chain polymers in Examples 1 and 2 is an experimental method for the reversible addition-fragmentation chain transfer polymerization reaction of sulfur free radicals. Specifically, in a 10 mL Schlenk reaction tube, allyl sulfide chain transfer agent (0.004 mmol), allyl sulfide macrocyclic monomer (0.1 mmol), AIBN (0.002 mmol), and DMF (1 mL) were added. Nitrogen gas was purged three times, and the reaction was carried out at 70 °C under a nitrogen atmosphere for 15 h. After the reaction, a small amount of dichloromethane was added, followed by precipitation with diethyl ether. This process was repeated twice, and the polymers were dried under vacuum to obtain the corresponding polymers P1 or P2, which were then characterized by gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (NMR).

[0096] Example 1

[0097] Preparation of polymer P1

[0098] Following the experimental method described above for the reversible addition-fragmentation chain transfer polymerization reaction of sulfur free radicals, using allyl sulfur macrocyclic monomer M1 (0.1 mmol) and allyl sulfur chain transfer agent CTA3 (0.004 mmol) as reactants, polymer P1 (conversion rate 85%) was obtained. n =11900, The structural formula of polymer P1 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3): δ7.99-7.84(m,1H),7.65-7.48(m,3H),6.29(s,1H),5.73-5.49(m,1H),5.16-5.00(m,2H),4.14(t,J=5.9 Hz,2H),3.76-3.27(m,5H),3.26-2.84(m,2H),2.78-2.60(m,2H),2.58-2.12(m,5H),1.78-1.56(m,4H),1.42(q,J=7.9Hz,2H). 13 C NMR (100MHz, CDCl3): δ173.4,168.2,137.0,136.3,135.5,135.4,134.2,132.9,129.8,129.7,129.5,129.5,118.3 ,118.2,63.3,63.2,52.2,51.6,50.9,48.6,45.5,44.4,42.6,40.3,34.1,33.7,31.5,31.2,31.0,29.0,26.5,24.6.

[0099]

[0100] Dynamics study

[0101] The polymerization reaction in this embodiment was monitored using proton nuclear magnetic resonance (HMR) spectroscopy. Samples were taken at reaction times of 1h, 2h, 3h, 4h, 5h, 6h, and 9h for HMR analysis to calculate the conversion rate. GPC analysis was also performed to calculate the polymer's molecular weight and molecular weight distribution coefficient. The final experimental results are as follows: Figure 5 and Figure 6 As shown. By Figure 5 It can be seen that polymerization reactions follow first-order kinetics. From... Figure 6 It can be seen that the polymer molecular weight has a linear relationship with the monomer conversion rate, and the molecular weight distribution coefficient is basically maintained below 1.3. The above experimental results indicate that the polymerization reaction was very well controlled.

[0102] Example 2

[0103] Preparation of polymer P2

[0104] Following the experimental method described above for the reversible addition-fragmentation chain transfer polymerization reaction of sulfur free radicals, using allyl sulfur macrocyclic monomer M2 (0.1 mmol) and allyl sulfur chain transfer agent CTA3 (0.004 mmol) as reactants, polymer P2 (conversion rate 77%) was obtained. n =15500, The structural formula of polymer P2 is shown below. NMR characterization results: 1 H NMR (400MHz, CDCl3): δ7.99-7.86(m,1H),7.65-7.47(m,3H),6.21(s,1H),5.73-5.50(m,1H),5.18-5.03(m,2H),4.14(q,J=6. 6Hz,2H),3.73-3.31(m,5H),3.27-2.84(m,2H),2.78-2.60(m,2H),2.58-2.11(m,5H),1.82-1.47(m,4H),1.40-1.18(m,12H). 13 C NMR (100MHz, CDCl3): δ173.7,168.1,137.0,136.3,135.5,135.5,134.2,132.9,129.9,129.7,129.6,129.5,118.3,118.2,63.3,6 3.2,52.2,51.6,50.8,48.6,45.5,44.4,42.6,40.7,34.3,33.7,31.5,31.2,31.0,29.6,29.5,29.4,29.3,29.3,29.2,27.1,25.0.

[0105]

[0106] Examples 3-7 and Comparative Example 1

[0107] Optimization of chain transfer agents

[0108] The difference between Examples 3-7 and Example 1 is that the chain transfer agents used in Examples 3-7 are different from those in Example 1: CTA1 was used in Example 3, CTA2 in Example 4, CTA4 in Example 5, CTA5 in Example 6, and CTA6 in Example 7. The reaction parameters of the main chain polymers in Examples 3-7 are the same as those in Example 1. The difference between Comparative Example 1 and Example 1 is that no chain transfer agent was added in Comparative Example 1.

[0109] The monomer conversion rate, polymer molecular weight, and molecular weight distribution of the polymer reaction processes in Examples 1, 3-7 are shown in Table 1 and 2. Figure 1 As shown in Table 1. Gel permeation chromatography (GPC) was used for determination with tetrahydrofuran as the mobile phase and polystyrene as the standard. Figure 1 It can be seen that the polymerization reaction in Example 1 can be well controlled when CTA3 is used as a chain transfer agent. According to GPC readings, a polymer with a number average molecular weight of 11,900 and a molecular weight distribution coefficient of 1.29 is generated, and the molecular weight is close to the theoretical molecular weight.

[0110] Table 1

[0111]

[0112] Examples 8-11

[0113] Optimization of reaction solvent types

[0114] The difference between Examples 8-11 and Example 1 is that the organic solvents are different. Specifically, Toluene was used in Example 8, DMSO was used in Example 9, THF was used in Example 10, and 1,4-Dioxane was used in Example 11.

[0115] The monomer conversion rate, polymer molecular weight, and molecular weight distribution results obtained in the polymer reactions of Examples 1, 8, and 11 are shown in Table 2 and... Figure 2 As shown in Table 2. The GPC assay uses tetrahydrofuran as the mobile phase and polystyrene as the standard. Figure 2 It can be seen that the reaction effect is best when DMF is used as a solvent, followed by THF. The reaction effect is relatively poor when toluene is used as a solvent, which may be due to the poor solubility of the polymer in toluene.

[0116] Table 2

[0117]

[0118] Examples 12-14

[0119] The difference between Examples 12-14 and Example 1 lies in the monomer / chain transfer agent ratio. In Example 1, the monomer / chain transfer agent ratio was 25:1, in Example 12 it was 10:1, in Example 13 it was 50:1, and in Example 14 it was 100:1. That is, Examples 1 and Examples 12-14 yielded P1 with different molecular weights.

[0120] The monomer conversion rate, polymer molecular weight, and molecular weight distribution results obtained in the polymer reactions of Examples 1, 12-14 are shown in Table 3 and... Figure 3 As shown in Table 3. GPC determination uses tetrahydrofuran as the mobile phase and polystyrene as the standard. Figure 3 It is known that by adjusting the ratio of monomer to chain transfer agent, polymers P1 with molecular weights ranging from 6,000 to 22,000 can be prepared, and the molecular weight distribution is basically in the range of 1.2 to 1.5.

[0121] Table 3

[0122]

[0123]

[0124] Examples 15-17

[0125] The difference between Examples 15-17 and Example 2 lies in the monomer / chain transfer agent ratio. In Example 2, the monomer / chain transfer agent ratio was 25:1, in Example 15 it was 10:1, in Example 16 it was 50:1, and in Example 17 it was 100:1. That is, Examples 2 and Examples 15-17 yielded P2 with different molecular weights.

[0126] The monomer conversion rate, polymer molecular weight, and molecular weight distribution results obtained in the polymer reactions of Examples 2, 15-17 are shown in Table 4 and... Figure 4 As shown in Table 4. The GPC assay used tetrahydrofuran as the mobile phase and polystyrene as the standard. Figure 4 It is known that by adjusting the ratio of monomer to chain transfer agent, polymers P2 with molecular weights ranging from 9,000 to 30,000 can be prepared, and the molecular weight distribution is basically in the range of 1.2 to 1.5.

[0127] Table 4

[0128]

[0129] Application Example 1

[0130] Preparation of block copolymers.

[0131] Specific experimental method: First, allyl sulfide chain transfer agent CTA3 (0.01 mmol), allyl sulfide macrocyclic monomer M1 (0.1 mmol), AIBN (0.002 mmol), and DMF (1.0 mL) were added to a 10 mL Schlenk reaction tube. Nitrogen gas was purged three times, and the reaction was carried out at 70 °C under a nitrogen atmosphere for 15 h. After the reaction, a small amount of dichloromethane was added, followed by precipitation with diethyl ether. This process was repeated twice to obtain polymer P1, which was then characterized by GPC. Next, P1 (0.0083 mmol) was used as the chain transfer agent, and allyl sulfide macrocyclic monomer M2 (0.083 mmol), AIBN (0.00168 mmol), and DMF (0.788 mL) were added. Nitrogen gas was purged three times, and the reaction was carried out at 70 °C under a nitrogen atmosphere for 15 h. After the reaction, a small amount of dichloromethane was added, followed by precipitation with diethyl ether. This process was repeated twice to finally obtain the block copolymer P1-b-P2, which was then characterized by GPC.

[0132] Depend on Figure 7 The GPC characterization results show that, compared to the first block polymer P1(M) n =6300, The resulting diblock copolymer P1-b-P2(M) n =13900, The GPC curves of the copolymer P1-b-P2 showed a significant shift towards higher molecular weight molecules. The structural formula of the copolymer P1-b-P2 is shown below. NMR characterization results: 1 ¹H NMR (400MHz, CDCl₃): δ 8.02–7.83 (m, 1H), 7.66–7.47 (m, 3H), 6.39–6.14 (m, 1H), 5.71–5.48 (m, 1H), 5.17–4.99 (m, 2H), 4.14 (q, J = 6.6 Hz, 2H), 3.76–3.28 (m, 5H), 3.26–3.02 (m, 1H), 2.97–2.84 (m, 1H), 2.79–2.59 (m, 2H), 2.58–2.00 (m, 5H), 1.70–1.51 (m, 4H), 1.45–1.15 (m, 9H). The experimental results indicate that this polymerization method has significant application prospects in the synthesis of multi-block polymers.

[0133]

[0134] Application Example 2

[0135] Preparation of polymers with ester functional sequences in the main chain.

[0136] Specific experimental method: Allyl sulfide chain transfer agent CTA3 (0.004 mmol), allyl sulfide macrocyclic monomer M3 (0.1 mmol), AIBN (0.002 mmol), and DMF (1.0 mL) were added to a 10 mL Schlenk reaction tube. Nitrogen gas was purged three times, and the reaction was carried out at 70 °C under a nitrogen atmosphere for 15 h. After the reaction was completed, a small amount of dichloromethane was added, followed by precipitation with diethyl ether. This process was repeated twice, and the polymer P3(M3) containing ester functional sequences in its main chain was obtained after vacuum drying. n =8100, The structural formula of polymer P3 is shown below. NMR characterization results: ¹H NMR (400MHz, CDCl₃): δ 7.97-7.87 (m, ¹H), 7.66-7.49 (m, ³H), 6.53 (s, ¹H), 5.61 (dt, J = 15.7, 8.6Hz, ¹H), 5.18-5.05 (m, 2H), 4.60 (s, 2H), 4.34-4.12 (m, 4H), 3.76-3.45 (m, 4H), 3.38 (dd, J = 9.9, 4.2Hz,0.5H),3.28-3.05(m,1.5H),2.90(q,J=6.8,6.3Hz,0.5H),2.78-2.62(m,6.5H),2.53(dd ,J=17.3,7.5Hz,1H),2.42-2.30(m,1.5H),2.14(td,J=8.7,4.1Hz,0.5H),2.06-1.62(m,4H).13C NMR (100MHz, CDCl3): δ 172.3, 171.9, 168.6, 167.6, 136.9, 136.3, 135.5, 135.4, 134.2, 132.9, 129.8, 129.5, 129.5, 118.3, 118.2, 64.3, 64.2, 62.5, 60.9, 52.2, 51.6, 50.8, 48.5, 45.4, 44.4, 42.5, 37.2, 33.7, 31.5, 30.9, 30.7, 29.1, 28.9, 28.3. The experimental results indicate that this polymerization method has significant application potential in the preparation of main-chain functional polymer materials.

[0137]

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A main-chain polymer, characterized in that, The general structural formula of the main-chain polymer is as follows: ； Among them, R 1 C 12 H 25 Or MeO2CCH2, R 2 for t At least one of BuO2C, methoxyphenyl, phenyl, and hydrogen, R 3 Groups with any of the following structures: , where --- indicates the substitution position; the number-average molecular weight of the main chain polymer is (0.5~3) ten thousand, and the molecular weight distribution coefficient is 1.2~1.

5.

2. The main-chain polymer as described in claim 1, characterized in that, The main chain polymer has a structure of P1, P2, or P3: 。 3. The method for preparing the main-chain polymer according to claim 1, characterized in that, Includes the following steps: An allyl sulfide chain transfer agent, an allyl sulfide macrocyclic monomer, an initiator, and an organic solvent are mixed and reacted to obtain the main chain polymer. The allyl sulfide chain transfer agent comprises one of the following structures: CTA1, CTA2, CTA3, CTA4, and CTA6. The structure of the allyl thiomacrocyclic monomer includes one of M1, M2, and M3: ； The organic solvent is at least one of N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, and 1,4-dioxane; The molar ratio of the allyl sulfide macrocyclic monomer to the allyl sulfide chain transfer agent is (10~100):

1.

4. The method for preparing the main-chain polymer as described in claim 3, characterized in that, The reaction conditions are: a temperature of 60-80℃ and a protective atmosphere for 10-20 hours.

5. The method for preparing the main-chain polymer as described in claim 3, characterized in that, The molar ratio of the allyl sulfide chain transfer agent to the initiator is (1~3):

1.

6. The method for preparing the main-chain polymer as described in claim 3, characterized in that, The allyl thiomacyclomonomer is mixed with the organic solvent to form a solution, wherein the molar concentration of the allyl thiomacyclomonomer in the solution is 0.05~0.2M.

7. The use of the main-chain polymer according to any one of claims 1 to 2 in the preparation of block copolymers or polymers whose main chain contains ester groups.

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