Polyisomonoolefin copolymer, initiator system and use

Abstract

The present application belongs to the field of high molecular compounds and its preparation, and particularly relates to a polyisomonoolefin copolymer, an initiator system and application. The copolymer is prepared by copolymerizing a first monomer and a second monomer under an initiator system, wherein the first monomer is selected from isomonoolefins, and the second monomer comprises unsubstituted or substituted vinyl aromatics. The copolymer is used as an elastomer in asphalt modifier, medical material, 5G optical fiber protective layer or hot melt adhesive.

Description

Technical Field

[0001] This invention belongs to the field of polymer compounds and their preparation, specifically relating to a polyisoolefin copolymer, an initiator system, and its applications. Background Technology

[0002] Polystyrene-isobutylene-styrene (SIBS) is a triblock copolymer prepared by cationic polymerization of isobutylene as the main monomer and styrene as the second monomer using activated carbon. Polystyrene, acting as the hard segment, and polyisobutylene, acting as the soft segment, undergo covalent bonding and microphase separation. The polystyrene phase within the polyisobutylene phase forms a thermoplastic elastomer through physical crosslinking. During the polymerization process, SIBS can achieve different mechanical properties by changing the styrene / isobutylene ratio and molecular weight. SIBS with a lower styrene ratio exhibits mechanical properties similar to rubber, while SIBS with a higher styrene ratio resembles toughened plastics.

[0003] Patent document CN1982350A reports a cationic polymerization process using water as an initiator and a Lewis acid as a co-initiator, followed by the addition of a second monomer, either an isoolefin or a styrene-based monomer containing additives, to obtain a diblock copolymer. A third-stage polymerization is then performed with the addition of a first monomer containing additives to obtain a triblock copolymer. However, the SIBS polymer prepared by this method has a low molecular weight, unstable and easily transferred active centers, leading to frequent and difficult-to-control side reactions. Furthermore, other reported processes suffer from problems such as a wide molecular weight distribution of the resulting products and difficulties in processing due to excessively high molecular weights. For example, patent document CN1283681C reports a method for sequentially initiating the preparation of isobutylene block copolymers, but this method requires the addition of a new Lewis acid during the second-stage monomer copolymerization, making the synthesis process cumbersome. Summary of the Invention

[0004] To address the aforementioned problems, the present invention provides a copolymer prepared by copolymerizing a first monomer and a second monomer in an initiator system, wherein the first monomer is selected from isomonoolefins and the second monomer comprises unsubstituted or substituted vinyl aromatics.

[0005] According to an embodiment of the present invention, the copolymer is a thermoplastic copolymer (thermoplastic elastomer) or a thermosetting copolymer (thermosetting elastomer).

[0006] According to an embodiment of the present invention, the copolymer uses polyisocyanates as soft segments.

[0007] According to an embodiment of the present invention, the first monomer is selected from isobutylene.

[0008] According to an embodiment of the present invention, in the second monomer, the substituent of the substituted vinyl aromatic hydrocarbon is located on the aromatic ring and may be selected from one or more of the following groups: halogen, unsubstituted, or halogenated C.1-10 alkyl.

[0009] According to an embodiment of the present invention, the aromatic hydrocarbon is selected from C 6-20 Aromatic hydrocarbons, preferably benzene.

[0010] According to an embodiment of the invention, the second monomer may comprise a group selected from styrene or a styrene derivative. Preferably, the styrene derivative is selected from substituted styrene. The styrene substituent is substituted onto a phenyl group or a vinyl group, and the substituent is selected from one or more of the following groups: halogen, C 1-10 Alkyl or halogenated C 1-10 alkyl.

[0011] Preferably, the second monomer is selected from one, two, or more of the following compounds: styrene; [the following are compounds] subjected to one or more C [resources]. 1-10 Alkyl-substituted styrene, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, p-tert-butylstyrene; styrene substituted with one or more halogens, such as p-chlorostyrene, p-bromostyrene; styrene substituted with one or more monohalogenated alkyl groups or polyhalogenated C groups. 1-10 Alkyl-substituted styrene, such as p-chloromethylstyrene and p-bromomethylstyrene; phenyl and C 4-8 Cycloalkenyl-fused styrene, such as 4-vinylbenzocyclobutene (4-VBCB).

[0012] According to a preferred embodiment of the present invention, the second monomer comprises monomer A, which is selected from one, two or more of the following compounds: styrene; [the following compounds are not specified in the original text] 1-10 Alkyl-substituted styrene, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, p-tert-butylstyrene; styrene substituted with one or more halogens, such as p-chlorostyrene, p-bromostyrene; styrene substituted with one or more monohalogenated alkyl groups or polyhalogenated C groups. 1-10 Alkyl-substituted styrene, such as p-chloromethylstyrene and p-bromomethylstyrene;

[0013] as well as,

[0014] Monomer B, which may or may not be present, is selected from one, two, or more of the following compounds: phenyl and C. 4-8 Cycloalkenyl-fused styrene, such as 4-vinylbenzocyclobutene.

[0015] According to an embodiment of the present invention, the copolymer may be a thermoplastic elastomer.

[0016] According to an exemplary embodiment of the present invention, the second monomer of the thermoplastic elastomer is selected from monomer A, which is selected from one, two or more of the following compounds: styrene; [the following is a list of compounds]...1-10 Alkyl-substituted styrene, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, p-tert-butylstyrene; styrene substituted with one or more halogens, such as p-chlorostyrene, p-bromostyrene; styrene substituted with one or more halogens selected from monohalogenated or polyhalogenated C-type alkyl groups. 1-10 Styrene substituted with alkyl groups, such as p-chloromethylstyrene or p-bromomethylstyrene. Preferably, monomer A is selected from styrene.

[0017] According to an embodiment of the present invention, the thermoplastic elastomer copolymer includes linear polystyrene-isobutylene-styrene (SIBS) triblock copolymer and three-arm star-shaped polystyrene-isobutylene-styrene (SIBS) triblock copolymer;

[0018] Preferably, the linear polystyrene-isobutylene-styrene (SIBS) triblock copolymer has the structure shown in formula (i), and the three-armed star-shaped polystyrene-isobutylene-styrene (SIBS) triblock copolymer has the structure shown in formula (ii).

[0019]

[0020] Each x is the same or different and is independently selected from numbers between 40 and 7000, preferably numbers between 80 and 5000, such as 80, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000 or 5000;

[0021] Each y may be the same or different, and is independently selected from numbers between 20 and 3000, preferably between 50 and 2000, for example, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or 2000.

[0022] According to an embodiment of the present invention, the copolymer may be a thermosetting elastomer.

[0023] According to a preferred embodiment of the present invention, the second monomer of the thermosetting elastomer comprises monomer A, which is selected from one, two or more of the following compounds: styrene; [the following compounds are present in a specific order]; ... 1-10 Alkyl-substituted styrene, such as α-methylstyrene, p-methylstyrene, m-methylstyrene, p-ethylstyrene, p-tert-butylstyrene; styrene substituted with one or more halogens, such as p-chlorostyrene, p-bromostyrene; styrene substituted with one or more monohalogenated alkyl groups or polyhalogenated C groups. 1-10 Alkyl-substituted styrene, such as p-chloromethylstyrene and p-bromomethylstyrene;

[0024] as well as,

[0025] Monomer B is selected from one, two, or more of the following compounds: phenyl and C 4-8 Cycloalkenyl-fused styrene, such as 4-vinylbenzocyclobutene.

[0026] According to an exemplary embodiment of the present invention, the second monomer of the thermosetting elastomer comprises styrene and 4-vinylbenzocyclobutene.

[0027] According to an embodiment of the present invention, in the second monomer, the molar ratio of monomer A to monomer B is (80-100):(0-20), preferably (90-100):(0-10), and more preferably, the content of monomer B is not 0. For example, the molar ratio of monomer A to monomer B is 95:5.

[0028] According to embodiments of the present invention, the thermosetting elastomer copolymer includes linear poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS) and three-armed star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS).

[0029] Preferably, the linear poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS) has the structure shown in formula (iii), and the three-armed star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymer (xSIBS) has the structure shown in formula (iv).

[0030]

[0031]

[0032] Each x may be the same or different, and is independently selected from 40 to 7000, preferably from 80 to 5000, for example, 80, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000 or 5000;

[0033] Each y may be the same or different, and is independently selected from numbers between 20 and 3000, preferably between 50 and 2000, for example, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or 2000.

[0034] Each m may be the same or different and is independently selected from 0 to 10, preferably 0 to 1, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1.

[0035] According to an embodiment of the present invention, the Mn of the copolymer can be 4.0 × 10⁻⁶. 3 Up to 5.0×10 5 For example, 2.0×10 4 Up to 2.0×10 5 .

[0036] According to an embodiment of the present invention, the molecular weight distribution coefficient Mw / Mn of the copolymer can be from 1.10 to 2.50, such as from 1.10 to 2.00, for example from 1.15 to 1.40, preferably from 1.17 to 1.36.

[0037] According to an embodiment of the present invention, in the copolymer, the content of the second monomer is selected from 5 wt% to 50 wt%, for example, its content can be selected from 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%. t%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt %, 38wt%, 39wt%, 40wt%, 41wt%, 42wt%, 43wt%, 44wt%, 45wt%, 46wt%, 47wt%, 48wt%, 49wt% or 50wt%.

[0038] According to an embodiment of the present invention, in the copolymer, when monomer A is present and monomer B is absent, the total content of the second monomer is 20 wt% to 50 wt%.

[0039] According to an embodiment of the present invention, in the copolymer, when monomers A and B are present simultaneously, the content of the second monomer is 5 wt% to 50 wt%.

[0040] According to an embodiment of the present invention, in the copolymer, the molecular weight of the first monomer segment can be from 2,000 to 400,000, for example, 2,000, 5,000, 10,000, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000 or 400,000; the molecular weight of the second monomer segment can be in the range of 2,000 to 300,000, for example, 2,000, 5,000, 100,000, 50,000, 100,000, 150,000, 200,000, 250,000 or 300,000.

[0041] According to a preferred embodiment of the present invention, the copolymer contains a gel with a mass percentage of less than 5 wt%, preferably less than 5 wt%, for example, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.4 wt%, or less than 0.3 wt%.

[0042] Less than 0.2wt% or less than 0.1wt%.

[0043] According to an embodiment of the present invention, the elongation at break of the thermoplastic elastomer copolymer is 200% to 1100%, and the ultimate tensile strength is 4 MPa to 30 MPa.

[0044] According to an embodiment of the present invention, the thermosetting elastomer copolymer has an elongation at break of 200% to 1100% and an ultimate tensile strength of 4.5 MPa to 50 MPa.

[0045] The present invention also provides a method for preparing a copolymer, preferably a method for preparing a copolymer as described above, such as a method for preparing a thermoplastic elastomer or a thermosetting elastomer, the method comprising copolymerizing a first monomer and a second monomer in an initiator system to obtain the copolymer, such as the thermoplastic elastomer or the thermosetting elastomer, wherein the first monomer and the second monomer have the definitions described above.

[0046] Preferably, the first monomer is added to the initiator system in batches.

[0047] According to an embodiment of the present invention, the initiator system comprises at least one initiator, such as a primary initiator or a combination of a primary initiator and a co-initiator.

[0048] According to embodiments of the present invention, the main initiator is selected from at least one of bifunctional initiators and multifunctional initiators. Exemplarily, the bifunctional initiator is used to prepare linear polymers. Exemplarily, the multifunctional initiator is used to prepare three-armed star polymers.

[0049] According to an embodiment of the present invention, the bifunctional initiator has two functional groups that are the same or different from each other.

[0050] Preferably, the bifunctional initiator includes, but is not limited to, at least one selected from the following: p-cumulol, p-cumulyl chloride, 1,3-bis(2-chloroisopropyl)benzene, 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene, 1,3-bis(2-methoxyisopropyl)benzene, or 5-tert-butyl-1,3-bis(2-methoxyisopropyl)benzene.

[0051] According to an embodiment of the present invention, the multifunctional initiator has three or more identical functional groups or has three or more functional groups, wherein at least one functional group is different from the other functional groups.

[0052] Preferably, the multifunctional initiator includes, but is not limited to, at least one selected from the following: 1,3,5-tricumyl alcohol, 1,3,5-tris(2-chloroisopropyl)benzene, or 1,3,5-tris(2-methoxyisopropyl)benzene.

[0053] According to an embodiment of the present invention, the main initiator is selected from at least one of the compounds represented by formula (A):

[0054]

[0055] Wherein, X is selected from tBu (tert-butyl), iPr (isopropyl), OMe (methoxy), 2-methoxyisopropyl, 2-chloroisopropyl, NO2, Cl, Br, I or H;

[0056] Each Y may be the same or different, and is independently selected from H, NO2, isopropyl or tert-butyl;

[0057] Z is selected from H, NO2, or tert-butyl;

[0058] R is selected from Cl, methyl (-Me), or methoxy (-OMe).

[0059] According to an embodiment of the present invention, the compound represented by formula (A) may be selected from compounds 1-22 having the following groups X, Y, Z and R:

[0060]

[0061]

[0062] According to an embodiment of the present invention, when X is tBu, Y is H, Z is H and R is Me, the compound represented by formula (A) is compound 1, namely 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene.

[0063] According to an embodiment of the present invention, when X is ClC(CH3)2-, Y is H, Z is H and R is Cl, the compound shown in formula (A) is compound 21, namely 1,3,5-tris(2-chloroisopropyl)benzene.

[0064] According to an embodiment of the present invention, when X is CH3OC(CH3)2-, Y is H, Z is H and R is OMe, the compound shown in formula (A) is compound 22, namely 1,3,5-tris(2-methoxyisopropyl)benzene.

[0065] According to an embodiment of the present invention, the copolymer is prepared by a cationic polymerization reaction. For example, a first monomer is added batch-wise to the initiator system to initiate polymerization, followed by the addition of a second monomer for copolymerization, to prepare the copolymer.

[0066] According to an embodiment of the present invention, a first portion of a first monomer is first added to the initiator system, then a second portion of the first monomer is added, followed by the addition of a second monomer to prepare the copolymer.

[0067] According to an embodiment of the present invention, an exemplary method for adding the first monomer in batches may include: firstly, initiating polymerization of a first portion of the first monomer with the initiator system to form a stable primary active center; then adding a second portion of the first monomer to prepare a polyisobutylene containing multiple active chain ends. The inventors have found that this method of adding the first monomer in batches effectively avoids severe chain transfer and chain termination reactions caused by excessive heat concentration.

[0068] Preferably, the amount of the first monomer added in the first portion is lower than the amount of the first monomer added in the second portion. More preferably, the first monomer in the first portion accounts for less than 40 wt% of the total mass of the first monomer, for example, 3 wt% to 40 wt%, preferably 10 wt% to 30 wt%; the second monomer in the second portion is the balance of the first monomer excluding the first monomer in the first portion.

[0069] According to an embodiment of the present invention, the conversion rate of the second monomer reaches 50 wt% to 100 wt%.

[0070] According to an embodiment of the present invention, the preparation method is carried out in the presence of a solvent. The solvent is selected from at least one of chloroalkanes, methylcyclohexane, or cyclohexane.

[0071] Preferably, the chloroalkane is selected from monochloromethane or polychloromethane.

[0072] Furthermore, the chloromethane is selected from at least one of monochloromethane, dichloromethane, or trichloromethane.

[0073] More preferably, the solvent system is selected from mixed solvents. For example, the mixed solvent is selected from cyclohexane and chloromethane, or hexane and chloromethane.

[0074] According to an embodiment of the present invention, preferably, in order to increase the participation of the second monomer styrene and its derivatives in block polymerization, the second monomer is provided in the form of a second monomer solution.

[0075] Preferably, the flow rate of the second monomer solution is 0.1 to 10 mL / s, for example, controlled by a metering pump or a separatory funnel, thereby reducing the heat released per unit time, ensuring uniform heat release in the reaction, and avoiding the occurrence of side reactions.

[0076] According to an embodiment of the present invention, the initiator system further includes a third component.

[0077] According to a preferred embodiment of the present invention, the initiator system further comprises a proton trapping agent.

[0078] Preferably, the third component is selected from aromatic compounds having p-π conjugation.

[0079] Preferably, the aromatic compound is selected from at least one of aromatic esters, aromatic ethers, or aromatic ketones.

[0080] More preferably, the aromatic ketone is selected from at least one of benzophenone, acetophenone, 2,4-dimethylacetophenone, phenylacetone, etc.

[0081] More preferably, the aromatic ether is selected from at least one of anisole, phenethyl ether, diphenyl ether, p-ethylphenethyl ether, n-butylphenyl ether, p-tert-butylphenethyl ether, etc.

[0082] More preferably, the aromatic ester is selected from at least one of methyl benzoate, ethyl benzoate, ethyl phenylacetate, dimethyl terephthalate, diethyl terephthalate, diethyl terephthalate, diethyl isophthalate, diethyl phthalate, dibutyl terephthalate, 2,6-dimethyl terephthalate, dimethyl phthalate, diethyl phthalate, and diisooctyl phthalate.

[0083] Preferably, the proton scavenger is selected from tertiary amine compounds, such as substituted or unsubstituted aromatic tertiary amine compounds, examples of which may be selected from at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine or 2,4,6-tri-tert-butylpyridine.

[0084] According to an embodiment of the present invention, the initiator system further includes a co-initiator.

[0085] Preferably, the co-initiator is selected from at least one of titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride (such as dichloroethylaluminum or trichlorotriethylaluminum).

[0086] According to an embodiment of the present invention, the co-initiator can be added to the initiator system after the first monomer in the first part is added, to initiate the polymerization reaction of the first part of isobutylene.

[0087] Furthermore, the total mass fraction of the first monomer and the second monomer raw materials in the total reaction system is 5 wt% to 45 wt%.

[0088] Furthermore, in the preparation of the thermosetting elastomer, the molar ratio of monomer A (e.g., styrene) to monomer B (e.g., 4-vinylbenzocyclobutene) in the second monomer is (80-100):(0-20), preferably (90-100):(0-10), for example (90-100):(1-10); wherein, in the molar ratio of monomer A to monomer B, when the proportion of monomer A is 90-100, it can be selected from 90, 91, 92, 93, 9... 4, 95, 96, 97, 98, 99, or 100; when the proportion of monomer B is 0 to 10, it can be selected from 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or 10.0. As an example, the molar ratio of monomer A to monomer B can be 95:5.

[0089] According to an embodiment of the present invention, in the initiator system, when a third component is present, the molar ratio of the third component to the main initiator is (0-10):1, for example, 0:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:1, 4.0:1, 4.5:1, 5.0:1, 5.5:1, 6.0:1, 6.5:1, 7.0:1, 7.5:1, 8.0:1, 8.5:1, 9.0:1, 9.5:1, or 10.0:1.

[0090] According to an embodiment of the present invention, in the initiator system, when a co-initiator is present, the molar ratio of the main initiator to the co-initiator is 1:(2-50), for example 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50.

[0091] According to an embodiment of the present invention, the molar ratio of the main initiator to the first monomer is 1:(40-7000), for example 1:50, 1:100, 1:200, 1:500, 1:1000, 1:1500, 1:2000, 1:2500, 1:3000, 1:3500, 1:4000, 1:4500, 1:5000, 1:5500, 1:6000, 1:6500, or 1:7000.

[0092] According to an exemplary embodiment of the present invention, when a proton scavenger is present, the molar ratio of the proton scavenger to the main initiator in the initiator system is (0-5):1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.5:1, 2.0:1, 2.5:1, 3.0:1, 3.5:1, 4.0:1, 4.5:1, or 5.0:1.

[0093] According to an embodiment of the present invention, in the preparation method, the temperature range of the copolymerization reaction is -100℃ to -50℃, preferably -90℃ to -50℃, for example -90℃, -80℃, -70℃, -60℃ or -50℃.

[0094] According to an embodiment of the present invention, the mass percentage of gel in the copolymer obtained by the preparation method is less than 5 wt%, preferably less than 5 wt%, for example less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, or less than 0.1 wt%.

[0095] According to an embodiment of the present invention, the preparation method forms a stable linear and / or star-shaped polymer structure.

[0096] The inventors unexpectedly discovered that because styrene and its derivatives have an electron-rich structure, they are susceptible to nucleophilic attack by carbocations, leading to alkylation reactions (as shown in reaction formula v below). This results in severe cross-linking between macromolecular chains, forming an insoluble gel in the system. For example, the block copolymer disclosed in CN201710177847.0 does not exceed 20 wt% in styrene content because, in the process described in that literature, if the styrene content in the block copolymer were further increased, intermolecular cross-linking would easily occur in the later stages of polymerization, forming a high-content gel. The reaction mechanism is shown in reaction formula v below.

[0097]

[0098] The present invention discovers that selecting at least one of aromatic esters, aromatic ethers or aromatic ketones as a third component, or combining the third component with a proton scavenger, can effectively reduce the gel content generated during copolymerization, thereby effectively increasing the conversion rate of the second monomer styrene and its derivatives in the reaction, and can also reduce the charge of the carbocation active center and stabilize the active center of the carbocation.

[0099] According to an embodiment of the present invention, a thermosetting elastomer is obtained by copolymerizing 4-vinylbenzocyclobutene into the polystyrene-based hard segment of SIBS by adding 4-vinylbenzocyclobutene copolymer units when adding the second monomer styrene. The difficulty of 4-VBCB participating in the copolymerization reaction and its unfavorable copolymerization with the first monomer during block polymerization is effectively solved by adding at least one of aromatic esters, aromatic ethers, or aromatic ketones as a third component, or by combining it with a proton trapping agent. Subsequently, through thermal crosslinking (as shown in reaction formula ⅵ below), the mechanical properties of the material are greatly improved.

[0100]

[0101] The present invention also provides an initiator having a structure as shown in formula (A) as described above, such as compounds 1-22 described above.

[0102] This invention also provides a method for preparing an initiator, the method specifically comprising the following steps:

[0103] (1) Compound B is esterified with methanol in concentrated sulfuric acid to generate intermediate product B-1;

[0104] (2) Intermediate product B-1 is reacted with Grignard reagent in an organic solvent to generate intermediate product B-2;

[0105] (3) The intermediate product B-2 is reacted with methanol by acidification to obtain compound A, or

[0106] (4) Dry hydrogen chloride gas was passed into a solution of intermediate product B-2 in dichloromethane to obtain compound A.

[0107]

[0108] In compound B, X' is selected from tBu, iPr, OMe, -COOH, NO2, Cl, Br, I, or H;

[0109] In intermediate product B-1, X” is selected from tBu, iPr, OMe, -COOMe, NO2, Cl, Br, I or H;

[0110] In intermediate product B-2, X”' is selected from tBu, iPr, OMe, -C(CH3)2OH, NO2, Cl, Br, I or H;

[0111] X, Y, Z, and R have the meanings described above.

[0112] According to an embodiment of the present invention, the preparation method is preferably carried out in an inert atmosphere, such as a nitrogen atmosphere.

[0113] According to an embodiment of the present invention, in step (2), the Grignard reagent is selected from CH3MgBr and / or CH3MgI.

[0114] According to an embodiment of the present invention, in step (2), the organic solvent comprises at least one selected from tetrahydrofuran, 2-methyltetrahydrofuran, and cyclopentyl methyl ether.

[0115] Preferably, the organic solvent further comprises an optional aromatic solvent, such as benzene or toluene. For example, the aromatic solvent constitutes 0% to 50% of the organic solvent by volume. When present, the aromatic solvent constitutes 1% to 50% of the organic solvent by volume, for example, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0116] According to an embodiment of the present invention, in step (2), the reaction temperature is 0℃~40℃.

[0117] According to an embodiment of the present invention, in step (3), the acidification reaction is carried out in the presence of an acidification catalyst. Preferably, the acidification catalyst is selected from sulfuric acid.

[0118] According to an embodiment of the present invention, in the preparation method, the intermediate products B-1 and B-2 of the reaction process are improved by extraction, washing, recrystallization and drying processes, which solves the problem of difficult preparation and post-processing, and the purity of the product is at least 95%.

[0119] According to an embodiment of the present invention, in the preparation method, steps (2) and (3) preferably include a quenching step. The quenching step can be carried out by slowly adding the terminating agent dropwise first, followed by adding the terminating agent, to avoid violent exothermic reactions that could affect the quality of the product. Preferably, the terminating agent is selected from aqueous solutions of sodium sulfite and / or ammonium chloride, and more preferably from saturated aqueous solutions of sodium sulfite and / or saturated aqueous solutions of ammonium chloride.

[0120] According to an embodiment of the present invention, in the preparation method, in step (4), dry hydrogen chloride gas is continuously introduced for 12 to 48 hours. Preferably, in step (4), the exhaust gas is slowly absorbed with an alkaline aqueous solution, such as an aqueous sodium hydroxide solution, to prevent environmental pollution.

[0121] According to an embodiment of the present invention, in the preparation method, when X' in B is selected from tBu, iPr, OMe, NO2, Cl, Br, I or H, B can be obtained by oxidizing B' with potassium permanganate.

[0122]

[0123] According to an exemplary embodiment of the present invention, the preparation method of compounds 1-20 specifically includes the following steps:

[0124] (1) SM-0 is oxidized with acidic potassium permanganate to produce product SM-01;

[0125] (2) SM-01 reacts with methanol in concentrated sulfuric acid to produce product SM-02;

[0126] (3) SM-02 reacts with Grignard reagent to generate product SM-03;

[0127] (4) Dry hydrogen chloride gas was passed through SM-03 in a dichloromethane solution to obtain product SM-04; wherein SM-04 was selected from any one of compounds 1-20;

[0128]

[0129] Among them, X, Y, and Z have the meanings described above;

[0130] IPA stands for isopropanol, THF stands for tetrahydrofuran, and DCM stands for dichloromethane.

[0131] According to an exemplary embodiment of the present invention, the preparation method of compounds 21-22 may include the following steps:

[0132] (1) I reacts with methanol in concentrated sulfuric acid to produce product II;

[0133] (2) Ⅱ reacts with Grignard reagent in solvent to produce product Ⅲ;

[0134] (3) Ⅲ reacts with concentrated sulfuric acid in methanol to produce product Ⅳ, namely compound 22; or Ⅲ is passed through a solution of dichloromethane with dry hydrogen chloride gas to produce product Ⅴ, namely compound 21;

[0135]

[0136] The present invention also provides a method for preparing the above-mentioned compound B-2, comprising reacting compound B-1 with a Grignard reagent in an organic solvent to prepare compound B-2. Wherein, the organic solvent and the Grignard reagent have the meanings described above.

[0137] The present invention also provides the use of an organic solvent comprising at least one selected from tetrahydrofuran, 2-methyltetrahydrofuran, and cyclopentyl methyl ether in the preparation of compound B2.

[0138] Preferably, the organic solvent further comprises an aromatic solvent, such as benzene or toluene. For example, the toluene accounts for 0% to 50% of the volume of the organic solvent.

[0139] The present invention also provides uses of the copolymer (such as thermoplastic elastomers or thermosetting elastomers), for example, the copolymer can be used in asphalt modifiers, medical fields such as medical materials, 5G optical fiber protective layers or hot melt adhesives, for example as an elastomer in asphalt modifiers, medical materials, 5G optical fiber protective layers or hot melt adhesives.

[0140] The medical material can be selected from materials such as glaucoma catheters (drainage tubes), intracorneal contact lenses, artificial lenses, drug delivery carriers, artificial blood vessels, and tissue fillers.

[0141] Terminology Definitions and Explanations

[0142] Unless otherwise stated, the definitions of groups and terms recorded in this application specification and claims, including their definitions as examples, exemplary definitions, preferred definitions, definitions recorded in tables, and definitions of specific compounds in the examples, can be arbitrarily combined and combined with each other. Such combinations and combinations of group definitions and compound structures shall fall within the scope of this application specification.

[0143] Unless otherwise stated, the numerical ranges described in this specification and claims are equivalent to describing at least each specific integer value therein. For example, the numerical range "1-10" is equivalent to describing each integer value in the numerical range "1-10", namely 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when certain numerical ranges are defined as "numbers", it should be understood that they describe the two endpoints of the range, each integer within the range, and each decimal within the range. For example, "numbers from 1 to 10" should be understood to describe not only each integer of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, but also at least the sum of each of these integers with 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9.

[0144] It should be understood that when describing one or more, "multiple" in this article means two or more, such as an integer greater than or equal to 2, such as 3, 4, 5, 6, 7, 8, 9 or 10.

[0145] The term "halogen" refers to fluorine, chlorine, bromine, and iodine, with chlorine or bromine being preferred.

[0146] Term "C" 1-10 "Alkyl" should be understood as representing a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 10 carbon atoms. For example, "C 1-6 "Alkyl" means a straight-chain or branched alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, or their isomers.

[0147] The term "halogenated C" 1-10 "Alkyl" refers to a C that has been substituted with one or more halogens. 1-10 Alkyl group. Unless otherwise specified, C 1-10 Alkyl groups have the definition described above.

[0148] The term "vinyl aromatic hydrocarbons" refers to aromatic hydrocarbons that have been replaced by vinyl groups.

[0149] The term "aromatic hydrocarbon" should be understood as a monocyclic, bicyclic (such as fused ring, bridged ring, spiro ring), or tricyclic hydrocarbon ring possessing aromatic properties. It can be a monoaromatic ring or a polyaromatic ring fused together, preferably "C". 6-20 "Aromatics" or "C" 6-14 Aromatic hydrocarbons. For example, "C 6-14 "Aromatic hydrocarbon" should be understood to preferably refer to a monocyclic, bicyclic, or tricyclic hydrocarbon ring having 6, 7, 8, 9, 10, 11, 12, 13, or 14 carbon atoms, exhibiting monovalent aromaticity or partial aromaticity ("C"). 6-14 Aromatic hydrocarbons, particularly rings with six carbon atoms (“C6 aromatic hydrocarbons”), such as benzene. 6-20 When aromatic hydrocarbons are substituted, they can be monosubstituted or polysubstituted. Furthermore, there are no restrictions on the substitution site; for example, they can be ortho, para, or meta substituted.

[0150] Beneficial effects

[0151] 1. The inventors unexpectedly discovered that the present invention significantly reduces the gel content of polyisocyanate copolymers (such as thermoplastic / thermosetting elastomers). The prepared copolymers have controllable structure, molecular weight and comonomer ratio, excellent mechanical properties, and a narrow molecular weight distribution. They also have excellent biocompatibility and broad application prospects. For example, they can be used as raw materials for the preparation of drug controlled release, in vitro catheters, implantable stents, etc., such as in ophthalmic implant materials, vascular stent coatings, glaucoma catheters and heart valves.

[0152] 2. This invention adds a third component to the initiator system of polyisocyanate copolymers, which can form stable primary active centers. Furthermore, by controlling the feeding rate of the second monomer, the gelation phenomenon during block polymerization is effectively suppressed, the conversion rate of styrene and its derivatives in the reaction is improved, and stable linear and star-shaped structures are formed.

[0153] 3. This invention copolymerizes 4-vinylbenzocyclobutene (4-VBCB) copolymer units into the polystyrene-based hard segments of SIBS, obtaining a poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock thermosetting elastomer copolymer. This solves the problem of 4-VBCB's low reactivity hindering its participation in copolymerization. Furthermore, thermal crosslinking significantly improves the material's ultimate tensile strength, and the hardness and post-crosslinking strength can be controlled by adjusting the amount of 4-VBCB used.

[0154] 4. This invention relates to a method for preparing copolymer elastomers with polyisobutylene as the soft segment using a batch feeding method in an initiator system via a living / controllable cationic polymerization system. In this method, a low-concentration isobutylene is first polymerized to form stable primary active centers; then, a second portion of isobutylene monomer is added to prepare polyisobutylene with multiple active chain ends. Subsequently, a second monomer, styrene, and its derivatives are added to prepare linear or three-armed star-shaped polystyrene-isobutylene-styrene triblock copolymers (SIBS) and linear or three-armed star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymers (xSIBS). This invention effectively avoids severe chain transfer and chain termination reactions caused by excessive exothermic concentration through the batch addition of isobutylene, resulting in a narrow polymer molecular weight distribution and thus obtaining linear or three-armed star-shaped polymers with controllable molecular structures.

[0155] 5. This invention also provides a new method for preparing bifunctional and multifunctional main initiators by improving process conditions, solving the potential danger of solvent explosion upon contact with air in traditional Grignard reactions, and promoting complete product conversion. In the preparation method of the main initiator, this invention improves upon the difficulties in preparation and post-processing, greatly increasing production efficiency and successfully scaling up the main initiator preparation process to an industrial-scale production level. By developing a series of new initiator derivatives, initiators with higher initiation efficiency and purity for cationic polymerization have been prepared. Using the initiators of this invention, linear or three-armed star polymers with controllable molecular structures can be synthesized. Attached Figure Description

[0156] Figure 1 This is the NMR spectrum of the bifunctional initiator (compound 1) prepared in Example 1. Detailed Implementation

[0157] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0158] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0159] I. Preparation Example

[0160] Preparation Example 1: Preparation of a bifunctional initiator (compound 1)

[0161] In this embodiment, SM-0, SM-1, SM-2, and SM-3 have the chemical structures described above, wherein when present, X is tBu, Y is H, Z is H, and R is Cl.

[0162] (1) First, IPA (isopropanol), water and SM-0 were added to the reactor in sequence; then the temperature was raised and 3.0 kg KMnO4 was added in batches, and the reaction was carried out under reflux and stirring. After the reaction system cooled to room temperature, saturated sodium sulfite was added dropwise to terminate the reaction. Then the centrifuged liquid was collected, the solid was collected and dried, and then dried to obtain product SM-01.

[0163] (2) Methanol and SM-01 were added to the reaction vessel in sequence, and the mixture was heated to reflux. Then concentrated sulfuric acid was added dropwise, and the reaction was completed. The system was then cooled to room temperature, centrifuged to obtain a white solid, and dried to obtain the white solid product SM-02.

[0164] (3) SM-02, 2-methyltetrahydrofuran, and toluene solvent (v:v = 60:40) were added sequentially to the reactor. CH3MgBr was added dropwise slowly. The system was protected by nitrogen throughout the process. The reaction was stirred at room temperature. After the raw materials were completely converted, saturated ammonium chloride was added dropwise to quench the reaction. The aqueous phase was extracted once with ethyl acetate. The organic phases were then combined, washed, dried, and concentrated to obtain a white crude solid. The white solid was recrystallized to obtain SM-03 with a yield of 95%.

[0165] (4) Add SM-03 and dichloromethane sequentially to the reactor, continuously pass dry hydrogen chloride gas into the reaction system, and slowly absorb the tail gas with sodium hydroxide aqueous solution. Filter off the solid from the reaction system, wash the solid with dichloromethane, and recrystallize to obtain the white solid final product SM-04. The initiator is compound 1, namely 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene, with a yield of 92%.

[0166] Preparation Example 2: Preparation of trifunctional initiators (compounds 21, 22)

[0167] (1) In a 1000 mL single-necked flask, add 18 g (0.086 mol) of reactant I, 500 mL of anhydrous methanol, and 20 mL of concentrated sulfuric acid. In reactant I, X is ClC(CH3)2-, Y is H, and Z is H. Turn on the stirrer and circulating cooling water, and react at room temperature. After the reaction is complete, seal and allow to stand at low temperature. Filter the product using a funnel to obtain a white solid, and then dry it thoroughly to obtain product II, with a yield of 90%.

[0168] (2) Grignard reaction: In a 1000 mL three-necked flask, add 16 g (0.063 mol) of product II and 280 mL of THF. Turn on the stirring and circulating cooling water to maintain a nitrogen atmosphere. Slowly add 150 mL of methylmagnesium bromide dropwise to the reaction system using a syringe. Then, extract and dry the product in a mixture of 280 g crushed ice and 18 g ammonium chloride. Finally, recrystallize to obtain product III, with a yield of 93%.

[0169] (3) In a 250 mL single-necked flask, 14 g of compound III, 72.5 mL of methanol, and 0.0084 mL of concentrated sulfuric acid were added and reacted. After cooling, 100 mL of n-hexane was added. The upper layer was washed until neutral and dried. Finally, recrystallization was performed several times to obtain product IV, which is compound 21, namely 5-tert-butyl-1,3-tris(2-chloroisopropyl)benzene, with a yield of 95%.

[0170] (4) Add III and dichloromethane sequentially to the flask, and continuously pass dry hydrogen chloride gas into the reaction system. The tail gas is slowly absorbed with sodium hydroxide aqueous solution. Filter off the solid from the reaction system, then wash the solid with dichloromethane, concentrate the solid, and recrystallize to obtain a white solid final product V, which is compound 22, 1,3,5-tris(2-methoxyisopropyl)benzene, with a yield of 96%.

[0171] II. Examples

[0172] Example 1

[0173] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -70°C. 40 ml of dichloromethane, 60 ml of hexane, 8 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene (0.1 M), and 0.1 M of ethyl benzoate were added to the reactor. Then, 5 ml of titanium tetrachloride (0.4 M) was added to initiate a small amount of isobutylene prepolymerization. Subsequently, 1.57 ml (3 M) of styrene solution (hard segment monomer) was added to the polymerization system using a metering pump at a controlled flow rate (0.1 mL / s) to initiate the second-stage block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 1.

[0174] Example 2

[0175] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 40 ml of dichloromethane, 60 ml of methylcyclohexane, 25 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene (0.1 M), 0.1 M acetophenone, and 0.1 M anisole were added to the reactor. Then, 5 ml of titanium tetrachloride (0.4 M) was added to initiate the prepolymerization of isobutylene. Subsequently, 2.2 ml of 3 M styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (0.1 mL / s) to initiate the second-stage block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 2.

[0176] Example 3

[0177] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -60°C. 40 ml of dichloromethane, 60 ml of cyclohexane, 8 ml of isobutylene (1.25 M), 5 ml of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene (0.1 M), 5 ml of 2,6-di-tert-butylpyridine (0.2 M), and 5 ml of ethyl benzoate (0.2 M) were added to the reactor to initiate the polymerization of isobutylene. Then, 5 ml of titanium tetrachloride (0.4 M) was added to initiate the polymerization of isobutylene. Subsequently, 1.57 ml of styrene (3 M) solution was added to the polymerization system using a metering pump at a controlled flow rate (0.2 mL / s) to initiate the second-stage block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and dried under vacuum at 45°C to constant weight to obtain thermoplastic elastomer 3.

[0178] Example 4

[0179] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 300g of chloromethane, 450g of methylcyclohexane, 20g of isobutylene, 0.0034mol of 5-tert-butyl-1,3-di(1-methoxy-1-methyl-ethyl)benzene, 0.0034mol of ethyl benzoate, and 2,4-dimethylacetophenone were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.11mol of boron trifluoride diethyl ether solution. Then, a second batch of 120g of isobutylene was added in portions to continue the reaction. Subsequently, 120g of p-tert-butylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2mL / s) to initiate the second block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 4.

[0180] Example 5

[0181] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -70°C. 500g of dichloromethane, 750g of cyclohexane, 50g of isobutylene, 0.0062mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene, 0.0032mol of dimethyl terephthalate, and 0.012mol of 2,6-di-tert-butylpyridine were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14mol of boron trichloride diethyl ether solution. Then, a second batch of 170g of isobutylene was added in portions to continue the reaction. Subsequently, 200g of styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (4mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol solution containing ammonia was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 5.

[0182] Example 6

[0183] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -50°C. 115g of chloromethane, 175g of methylcyclohexane, 20g of isobutylene, 0.0062mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene, 0.0032mol of diethyl phthalate, and 0.0032mol of p-tert-butylphenanthrene were added to the reactor. 0.14mol of titanium tetrachloride was then added to initiate a small amount of isobutylene prepolymerization. A second portion of 100g of isobutylene was then added in batches to continue the reaction. Subsequently, 94g of styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (5mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol solution containing ammonia was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 6.

[0184] Example 7

[0185] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -90°C. 500g of chloromethane, 750g of cyclohexane, 50g of isobutylene, 0.0072mol of 1,3,5-triisopropylchlorobenzene, 0.012mol of acetophenone, and 0.0062mol of 2,6-di-tert-butyl-4-methylpyridine were added to the reactor. Then, 0.186mol of titanium tetrachloride was added to initiate a small amount of isobutylene prepolymerization. Next, 170g of the second portion of isobutylene was added in batches, and the reaction was continued for 70 minutes. Subsequently, 270g of p-methylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 7.

[0186] Example 8

[0187] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 130g of dichloromethane, 300g of methylcyclohexane, 20g of isobutylene, 0.0034mol of 1,3,5-tris(1-methoxy-1-methyl-ethyl)benzene (i.e., compound 22 in Preparation Example 2), and 0.0012mol of phenethyl ether were added to the reactor. Then, 0.136mol of ferric chloride was added to initiate a small amount of isobutylene prepolymerization. A second portion of 90g of isobutylene was then added in batches to continue the reaction. Subsequently, 185g of p-ethylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 8.

[0188] Example 9

[0189] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -50°C. 160g of dichloromethane, 240g of cyclohexane, 30g of isobutylene, 0.003mol of 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene (i.e., compound 1 of Preparation Example 1), 0.0017mol of 2,6-di-tert-butylpyridine, and 0.0017mol of phenethyl ether were added to the reactor. Then, 0.096mol of ferric chloride was added to initiate a small amount of isobutylene prepolymerization. A second portion of 70g of isobutylene was then added in batches to continue the reaction. Subsequently, 130g of styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 9.

[0190] Example 10

[0191] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -60°C. 240 g of chloromethane, 240 g of methylcyclohexane, 25 g of isobutylene, 0.0025 mol of the trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene (i.e., compound 21 in Preparation Example 2), 0.0012 mol of anisole, 0.0012 mol of benzophenone, and 0.002 mol of 2,4,6-triter-tert-butylpyridine were added to the reactor. Then, 0.096 mol of boron trifluoride diethyl ether solution was added to initiate a small amount of isobutylene prepolymerization. Next, 80 g of the second portion of isobutylene was added to continue the reaction. Subsequently, 160 g of p-tert-butylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2 mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 10.

[0192] Example 11

[0193] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 400g of dichloromethane, 930g of methylcyclohexane, 50g of isobutylene, 0.0062mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene, and 0.0032mol of methyl benzoate were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14mol of boron trichloride diethyl ether solution. Then, a second batch of 170g of isobutylene was added in portions to continue the reaction. Subsequently, 200g of α-methylstyrene solution was added to the polymerization system using a metering pump at a controlled flow rate (4mL / s) to initiate the second-stage block polymerization. Finally, a small amount of methanol solution containing ammonia was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 11.

[0194] Example 12

[0195] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -70°C. 400g of dichloromethane, 930g of methylcyclohexane, 60g of isobutylene, 0.0062mol of 5-tert-butyl-1,3-bis(1-methoxy-1-methyl-ethyl)benzene, 0.005mol of phenethyl ether, and 0.005mol of ethyl phenylacetate were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14mol of boron trifluoride diethyl ether solution. Then, a second batch of 170g of isobutylene was added in portions to continue the reaction. Subsequently, 200g of styrene solution was added to the polymerization system using a metering pump at a controlled flow rate (2mL / s) to initiate the second stage of block polymerization. Finally, a small amount of methanol solution containing ammonia was added to terminate the reaction. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermoplastic elastomer 12.

[0196] Example 13

[0197] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -70°C. 100 ml of n-hexane / dichloromethane with a volume ratio of 60 / 40 was added as a solvent and mixed thoroughly. 2 ml of isobutylene, 5 ml of (0.1 M) 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene (i.e., compound 1 of Preparation Example 1), and 5 ml of diisooctyl phthalate were added to the polymerization reactor. Then, 5 ml of (0.4 M) boron trichloride diethyl ether solution was added to initiate the prepolymerization of isobutylene. Subsequently, 6 ml of the second portion of isobutylene was added in batches to continue the reaction. Subsequently, 1.57 ml (3M) of hard-segment monomer styrene and 0.16 ml (0.3M) of 4-vinylbenzocyclobutene were added to the polymerization system at a controlled flow rate (0.1 mL / s) using a metering pump to initiate the second-stage block polymerization. Finally, pre-cooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum dried at 45 °C to constant weight to obtain thermosetting elastomer 13.

[0198] Example 14

[0199] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 200g of dichloromethane, 300g of methylcyclohexane, 25g of isobutylene, 0.003mol of the trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene, 0.0015mol of diisooctyl phthalate, and 0.0015mol of acetophenone were added to the reactor. A small amount of isobutylene prepolymerization was initiated by adding 0.14mol of boron trifluoride diethyl ether solution. Then, a second batch of 160g of isobutylene was added in portions to continue the reaction. Subsequently, 170g of styrene and 50g of 4-vinylbenzocyclobutene solution were added to the polymerization system using a metering pump at a controlled flow rate (1.5mL / s) to initiate the second stage of block polymerization. Finally, pre-cooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermosetting elastomer 14.

[0200] Example 15

[0201] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 300g of chloromethane, 300g of methylcyclohexane, 25g of isobutylene, 0.003mol of trifunctional initiator 1,3,5-tris(2-chloroisopropyl)benzene, 0.0015mol of anisole, and 0.0015mol of acetophenone were added to the reactor. Then, 0.14mol of titanium tetrachloride was added to initiate a small amount of isobutylene prepolymerization. A second portion of 160g of isobutylene was then added in batches to continue the reaction. Subsequently, 40g of styrene and 14g of 4-vinylbenzocyclobutene solution were added to the polymerization system using a metering pump at a controlled flow rate (1.5mL / s) to initiate the second stage of block polymerization. Finally, pre-cooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermosetting elastomer 15.

[0202] Example 16

[0203] A 4-liter low-temperature polymerization reactor was used. After baking, vacuuming, and purging with nitrogen, the reactor was cooled to -80°C. 300g of dichloromethane, 300g of cyclohexane, 30g of isobutylene, 0.003mol of 5-tert-butyl-1,3-bis(2-chloroisopropyl)benzene, 0.002mol of anisole, and 0.002mol of dibutyl terephthalate were added to the reactor. 0.14mol of ferric chloride was then added to initiate a small amount of isobutylene prepolymerization. A second portion of 160g of isobutylene was then added in batches to continue the reaction. Subsequently, 45g of styrene and 20g of 4-vinylbenzocyclobutene solution were added to the polymerization system using a metering pump at a controlled flow rate (1.5mL / s) to initiate the second stage of block polymerization. Finally, pre-cooled methanol containing a small amount of ammonia solution was added to terminate the polymerization. The product was then desolventized and vacuum dried at 45°C to constant weight to obtain thermosetting elastomer 16.

[0204] III. Comparative Example

[0205] Comparative Example 1a

[0206] Cooling liquid was pumped into a vacuum glove box and cooled to the polymerization temperature of -70°C. 100 ml of hexane / dichloromethane (volume ratio 60 / 40) was added to the treated polymerization flask as a solvent and mixed thoroughly. Then, an initiator system consisting of 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the third component EtOAc was added and aged for 5 min. After aging for 5 min, 8 ml (1.25 M) of the intermediate monomer isobutylene was added, and the reaction was continued for 45–60 min. Then, 1.57 ml (3 M) of the hard-segment monomer styrene was added, and the reaction was continued for another 90 min. Finally, methanol (CH3OH) was added to terminate the reaction. After terminating the reaction, the product was desolventized and dried under vacuum at 45°C to constant weight.

[0207] Comparative Example 2b

[0208] Cooling liquid was pumped into a vacuum glove box and cooled to the polymerization temperature of -80°C. 100 ml of hexane / dichloromethane (volume ratio 40 / 60) was added to the treated polymerization flask as a solvent and mixed thoroughly. Then, an initiator system consisting of 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(1-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the proton scavenger DTBP (2,6-di-tert-butylpyridine) was aged for 15 min. After aging, 25 ml (1.25 M) of the intermediate monomer isobutylene was added, and the reaction was continued for 45–60 min. Then, 2.2 ml (3 M) of the hard-segment monomer styrene was added, and the reaction was continued for another 90 min. Finally, methanol (CH3OH) was added to terminate the reaction. After terminating the reaction, the product was desolventized and dried under vacuum at 45°C to constant weight.

[0209] Comparative Example 3c

[0210] Cooling liquid was pumped into a vacuum glove box and cooled to the polymerization temperature of -80°C. 100 ml of hexane / dichloromethane (volume ratio 60 / 40) was added to the treated polymerization flask as a solvent and mixed thoroughly. Then, an initiator system consisting of 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(2-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator titanium tetrachloride, and 5 ml (0.2 M) of the proton scavenger DTBP was added and aged for 5 min. After aging for 5 min, 8 ml (1.25 M) of the intermediate monomer isobutylene was added, and the reaction was continued for 45–60 min. Then, 1.57 ml (3 M) of the hard-segment monomer styrene was added, and the reaction was continued for 90 min. Finally, methanol (CH3OH) was added to terminate the reaction. After terminating the reaction, the product was desolventized and dried under vacuum at 45°C to constant weight.

[0211] Comparative Example 13d

[0212] Cooling liquid was pumped into a vacuum glove box and cooled to the polymerization temperature of -70°C. 100 ml of hexane / dichloromethane (volume ratio 60 / 40) was added to the treated polymerization flask as a solvent and mixed thoroughly. Then, an initiator system consisting of 5 ml (0.1 M) of the main initiator 5-tert-butyl-1,3-bis(2-methoxy-1-methylethyl)benzene, 5 ml (0.4 M) of the co-initiator boron trifluoride diethyl ether solution, and 5 ml (0.2 M) of the proton scavenger DTBP was added and aged for 5 min. After aging for 5 min, 8 ml (1.25 M) of the intermediate monomer isobutylene was added, and the reaction was continued for 45–60 min. Then, 1.57 ml (3 M) of the hard-segment monomer styrene and 0.16 ml (0.3 M) of 4-vinylbenzocyclobutene were added, and the reaction was continued for another 90 min. Finally, methanol (CH3OH) was added to terminate the reaction. After terminating the reaction, the product was desolventized and dried under vacuum at 45°C to constant weight.

[0213] The experimental conditions and results of the above embodiments and comparative examples are summarized in Tables 1, 2 and 3 below:

[0214] Table 1

[0215]

[0216] Table 2

[0217]

[0218] Table 3

[0219] Example 1 793 20.1 Comparative Example 1a 602 15.5 Example 2 589 19.6 Comparative Example 2b 550 16.1 Example 3 700 18.2 Comparative Example 3c 603 17.8 Example 4 724 18.8 Example 5 662 16.3 Example 6 761 19.6 Example 7 635 15.6 Example 8 540 14.5 Example 9 610 14.8 Example 10 520 14.2 Example 11 630 19.2 Example 12 665 20.9 Example 13 698 21.2 Comparative Example 13d 563 17.6 Example 14 682 21.8 Example 15 320 9.6 Example 16 342 10.5

[0220] The above experimental data shows that this invention utilizes a living / controllable cationic polymerization system, under an initiator system, to prepare copolymers with polyisobutylene as soft segments, i.e., a method for preparing thermoplastic / thermosetting elastomers, through a batch feeding method. In the preparation method of this invention, a low-concentration isobutylene in the first part is first polymerized to form stable primary active centers; then, a second part of isobutylene monomer is added to prepare polyisobutylene containing multiple active chain ends; subsequently, styrene and its derivatives are added to prepare linear or three-armed star-shaped polystyrene-isobutylene-styrene triblock copolymers (SIBS) and linear or three-armed star-shaped poly(styrene-coblock-4-vinylbenzocyclobutene)-polyisobutylene-poly(styrene-coblock-4-vinylbenzocyclobutene) triblock copolymers (xSIBS).

[0221] Furthermore, the polymer was tested according to the People's Republic of China Petroleum and Chemical Industry Standard SH / T 1050-2014, Determination of Gel Content in Synthetic Raw Rubber. The mass percentage of gel in the copolymers prepared in the embodiments of the present invention was less than 5%.

[0222] The above embodiments effectively avoid severe chain transfer and chain termination reactions caused by excessive heat concentration by adding isobutylene in batches, thereby obtaining linear or three-armed star polymers with controllable molecular structure.

[0223] This invention employs an initiator system to synthesize thermoplastic / thermosetting elastomers, which can form stable primary active centers. The initiator system includes a main initiator, a co-initiator, a third component, and a proton trapping agent, wherein the main initiator includes bifunctional or multifunctional groups. By adding a third component to the initiator system, the above embodiments stabilize the active centers, effectively reduce the gel content in the copolymer, and improve the conversion rate of styrene and its derivatives in the reaction (the conversion rate of the second monomer reaches 50wt%–100wt%), forming stable linear and star-shaped polymer structures. In the polymerization preparation process of this invention, different mechanical properties can also be obtained by changing the first monomer / second monomer feeding ratio and relative molecular mass, resulting in a narrow molecular weight distribution of the obtained product.

[0224] This invention also provides a new method for preparing the main initiator by improving process conditions, solving the potential danger of explosion when the solvent comes into contact with air in traditional Grignard reactions, and promoting the complete conversion of the product. In the preparation method of the main initiator, the purification process of the intermediate products in each step further improves the difficult problems in preparation and post-processing, greatly increasing production efficiency and successfully scaling up the main initiator preparation process to meet industrial production standards. By developing a series of new initiator derivatives, initiators with higher initiation efficiency and higher purity for cationic polymerization have been prepared. Using the initiators of this invention, linear or three-armed star polymers with controllable molecular structures can be synthesized.

[0225] The copolymer can be used as a raw material for the preparation of drug controlled release, extracorporeal catheters, implantable stents, etc., for example, for ophthalmic implant materials, vascular stent coatings, glaucoma catheters, artificial blood vessels and heart valves.

[0226] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A copolymer prepared by copolymerizing a first monomer and a second monomer in an initiator system, characterized in that: The method for preparing the copolymer includes: adding a first portion of a first monomer to the initiator system to initiate polymerization, then adding a second portion of the first monomer, followed by adding a second monomer for copolymerization, to obtain the copolymer; wherein the first portion of the first monomer accounts for 3wt% to 40wt% of the total mass of the first monomer; the second monomer is provided in the form of a second monomer solution; the flow rate of adding the second monomer solution is 0.1 to 10 mL / s; The first monomer is selected from isobutylene, and the second monomer comprises monomer A and monomer B, which may or may not be present. The monomer A is selected from one, two or more of the following compounds: styrene; styrene substituted with one or more C1 alkyl groups; The monomer B is selected from 4-vinylbenzocyclobutene; The molar ratio of monomer A to monomer B is 80–100 : 0–20; In the copolymer, the total content of the second monomer is 5wt% to 50wt%; wherein, when monomer A is present and monomer B is absent, the total content of the second monomer is 20wt% to 50wt%; and when monomers A and B are both present, the content of the second monomer is 5wt% to 50wt%. In the copolymer, the mass percentage of gel is less than 5 wt%, the molecular weight distribution coefficient (Mw / Mn) of the copolymer is 1.10–2.50, and the Mn of the copolymer is 4.0 × 10⁻⁶. 3 Up to 5.0×10 5 The molecular weight of the first monomer segment is 0.2 million to 400,000, and the molecular weight of the second monomer segment is 0.2 million to 300,000. The initiator system comprises a main initiator or a combination of a main initiator and a co-initiator, and the initiator system further comprises a third component; the third component is selected from at least one of the following aromatic esters, aromatic ethers, or aromatic ketones: The aromatic ester is selected from at least one of methyl benzoate, ethyl benzoate, ethyl phenylacetate, dimethyl terephthalate, diethyl terephthalate, diethyl terephthalate, diethyl isophthalate, diethyl phthalate, dibutyl terephthalate, 2,6-dimethyl diethyl terephthalate, dimethyl phthalate, and diisooctyl phthalate; The aromatic ether is selected from at least one of anisole, phenethyl ether, diphenyl ether, p-ethylphenethyl ether, n-butylphenyl ether, and p-tert-butylphenethyl ether; The aromatic ketone is selected from at least one of benzophenone, acetophenone, 2,4-dimethylacetophenone, and phenylacetone; The main initiator has the structure shown in formula (A): （A） Wherein, X is selected from tert-butyl, isopropyl, methoxy, 2-methoxyisopropyl, 2-chloroisopropyl, NO2, Cl, Br, I or H; Each Y may be the same or different, and is independently selected from H, NO2, isopropyl or tert-butyl; Z is selected from H, NO2, or tert-butyl; R is selected from Cl, methyl, or methoxy; The co-initiator is selected from at least one of titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride.

2. The copolymer according to claim 1, characterized in that, The monomer A is selected from one, two or more of styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene.

3. The copolymer according to claim 1, characterized in that, The molar ratio of monomer A to monomer B is 90–100 : 0–10.

4. The copolymer according to claim 1, characterized in that, In the copolymer, the mass percentage of gel is less than 3 wt%.

5. The copolymer according to any one of claims 1-4, characterized in that, The copolymer is selected from the structure shown in formula (i), (ii), (iii) or (iv): (i) (ii) (iii) （ⅳ） Each x is either the same or different, and is independently selected from numbers between 40 and 7000; Each y is either the same or different, and each number is independently selected from 20 to 3000; Each m is either the same or different, and each is independently selected from numbers between 0 and 10.

6. Use of the copolymer according to any one of claims 1-5 in the preparation of asphalt modifiers, medical materials, 5G optical fiber protective layers or hot melt adhesives.

7. Use of the copolymer according to any one of claims 1-5 in the preparation of materials for glaucoma catheters, intraocular contact lenses, artificial lenses, drug delivery carriers, artificial blood vessels or tissue fillers.

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