WO2025218154A1 - Polyisobutylene-based copolymer and preparation method therefor - Google Patents

Abstract

The present invention belongs to the field of polymer compounds, and particularly relates to a thermally cross-linkable polyisobutylene-based block copolymer having a regular structure and a preparation method therefor. In the present invention, the polymerization of a first monomer IB is firstly initiated by means of active/controllable cationic polymerization; an end-capping reagent is then added thereto for end capping, so as to obtain a stable PIB+ active center; and a regulator is then added thereto to regulate the Lewis acidity and reaction activity of the system; and a second monomer 4-VBCB is then added thereto to continue the polymerization reaction, so as to prepare the polyisobutylene-based copolymer. The polyisobutylene-based copolymer of the present invention has good mechanical properties after being thermal crosslinked.

Description

Polyisobutylene-based copolymer and preparation method thereof Technical Field

The invention belongs to the field of polymer compounds, and in particular relates to a linear or star-shaped polyisobutylene-based block copolymer with a regular structure and capable of thermal cross-linking, and a preparation method thereof.

Background Art

Isobutylene (IB) is a cationically polymerizable monomer, and currently, polyisobutylene (PIB) can only be prepared through cationic polymerization. PIB has extensive commercial applications, and its alternating secondary and quaternary carbon structure in the backbone imparts excellent thermal and chemical stability, as well as unparalleled biocompatibility. However, with the exception of ultrahigh molecular weight PIB, PIB is generally a weak, liquid polymer. The advent of living cationic polymerization technology has made it possible to prepare PIB-based copolymers. Poly(styrene-b-polyisobutylene-b-polystyrene) (SIBS) is a typical example of such a copolymer. The polystyrene (PS) at each end serves as a hard segment, acting as a physical crosslink, while the PIB in the middle is a soft segment. The incompatibility of the two phases forms a microphase-separated structure, resulting in essential mechanical properties. Adjusting the ratio of the hard and soft segments allows for a wide range of tunable physical properties. SIBS also exhibits excellent biocompatibility and has achieved significant success in biomedical applications. However, the physical crosslinking structure in SIBS is limited by the glass transition temperature (Tg) of styrene, resulting in poor creep resistance and heat resistance.

Patent CN101918461B reports a monomer with a fused ring, 4-vinylbenzocyclobutene (4VBCB). This monomer, which also serves as a crosslinking agent, can be copolymerized with IB as a second monomer to form a PIB-co-4VBCB thermosetting random copolymer with two randomly distributed monomer units. This copolymer has similar properties to PIB before crosslinking, and can be directly chemically crosslinked by heating. The crosslinked copolymer has even better chemical stability, thermal stability, oxidation resistance, and creep resistance, effectively overcoming the performance deficiencies of SIBS. However, this random copolymerization method inevitably leads to various complex side reactions during the polymerization process, making the molecular weight of the final product uncontrollable, and the mass content of the second monomer uncontrollable. Furthermore, due to the difference in the activity of the two monomers, the copolymerized product often has a low molecular weight, a low crosslinking agent content, and a low yield, thus limiting the application of this copolymer.

Summary of the Invention

To address these issues, the present invention provides a structurally regular thermosetting elastomer polyisobutylene-based copolymer and a method for preparing the same. This method utilizes living/controllable cationic polymerization and can produce linear diblock copolymers (PIB-b-P4VBCB (polyisobutylene-b-polytetravinylphenylpropylcyclobutene), triblock copolymers (P4VBCB-b-PIB-b-P4VBCB (poly-4-vinylbenzocyclobutene-b-polyisobutylene-b-polytetravinylphenylpropylcyclobutene), or radial block copolymers with regular structural sequences, controllable molecular weight, and a controlled, narrowly distributed second monomer content. By regulating the product molecular weight or structural unit ratio, polyisobutylene-based copolymer thermosetting elastomers with various mechanical properties can be obtained. High-temperature crosslinking of the polyisobutylene-based copolymer thermosetting elastomer yields an elastomer with a stable chemically crosslinked structure.

The first technical problem to be solved by the present invention is to provide a method for preparing a polyisobutylene-based copolymer, comprising the following steps: firstly initiating polymerization of a first monomer (IB) through living/controllable cationic polymerization, then adding a capping agent to cap the first monomer to obtain a stable PIB+active center, then adding a regulator to adjust the Lewis acidity and reactivity of the system; then adding a second monomer (4-VBCB) to continue the polymerization reaction, terminating the reaction, and obtaining the polyisobutylene-based copolymer through post-treatment.

Specifically, the method for preparing a polyisobutylene-based copolymer according to the present invention comprises the following steps: polymerizing a proton scavenger, a primary initiator, a first portion of the first monomer IB, and a co-initiator in a solvent; then adding a second portion of the first monomer IB and continuing the polymerization reaction until the first monomer conversion rate reaches above 95%; then adding an end-capping agent to cap the reaction to obtain a stable PIB+ active center; then adding a regulator to adjust the Lewis acidity and reactivity of the system; then adding a second monomer, 4-VBCB, to continue the polymerization reaction; terminating the reaction, and post-processing to obtain the polyisobutylene-based copolymer. Specifically, in the above preparation method, the end-capping agent is at least one of 1,1-diphenylethylene (DPF), 1,1-di-p-tolylethylene (DTE), 2-methylfuran, and 2-tert-butylfuran. Preferably, the end-capping agent is 1,1-diphenylethylene or 1,1-di-p-tolylethylene.

Specifically, in the above preparation method, the regulator is at least one of Ti(OR)4, SnBr4, SnCl4, n-Bu4NCl, and BCl3, wherein R is a C1-4 alkyl group. Preferably, the regulator is titanium isopropoxide (Ti(OiPr)4) or Bu4NCl.

Specifically, in the above preparation method, the main initiator is or 2-chloro-2,4,4-trimethylpentane; wherein R1 is methyl, Cl or methoxy, and R2 and R3 are each independently Cl or methoxy.

Specifically, in the above preparation method, the coinitiator is at least one of titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkylaluminum chloride. Preferably, the coinitiator is titanium tetrachloride. The alkylaluminum chloride is selected from diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, and the like.

Specifically, in the above preparation method, the proton scavenger is at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine, and 2,4,6-tri-tert-butylpyridine. Preferably, the proton scavenger is 2,6-di-tert-butylpyridine.

Specifically, in the above preparation method, the solvent is a mixed solvent of solvent A and solvent B; wherein solvent A is at least one of chloromethane, dichloromethane, and chloroform, and solvent B is at least one of n-hexane, cyclohexane, and methylcyclohexane.

Furthermore, in the above preparation method, the volume ratio B/A of the mixed solvent is 7:3, 6:4, or 5:5, preferably 6:4.

Furthermore, in the above preparation method, the molar ratio of the first monomer to the second monomer is (60-99):(40-1).

Furthermore, in the above preparation method, the molar ratio of the main initiator to the first monomer is 1:(50-1000).

Furthermore, in the above preparation method, the molar ratio of the main initiator to the co-initiator is 1:(2-64).

Furthermore, in the above preparation method, the molar ratio of the end-capping agent to the main initiator is 1:(1-10).

Furthermore, in the above preparation method, the molar ratio of the regulator to the end-capping agent is (1-64):1.

Furthermore, in the above preparation method, the molar ratio of the proton scavenger to the end-capping agent is 1:(1-10).

Furthermore, in the above preparation method, the second monomer is mixed with solvent B and then added into the system. Furthermore, the volume ratio of the second monomer to solvent B is 1:(1-5).

Furthermore, in the above preparation method, the first portion of the first monomer accounts for 5 to 30 wt% of the total amount of the first monomer, and the second portion of the first monomer accounts for 70 to 95 wt% of the total amount of the first monomer.

Furthermore, in the above preparation method, the mass fraction of the total mass of the first monomer and the second monomer in the reaction system is 10 to 50%.

Specifically, in the above preparation method, each reaction is carried out in an anhydrous and oxygen-free atmosphere. Preferably, each reaction is carried out in an inert atmosphere.

Specifically, in the above preparation method, each reaction temperature is -50 to -100°C, preferably -80°C.

Specifically, in the above preparation method, the solvent is pre-cooled at the reaction temperature for 5 to 20 minutes before the proton scavenger, the primary initiator, and the first portion of the first monomer are added. After the proton scavenger, the primary initiator, and the first portion of the first monomer are added to the solvent, the entire system is pre-cooled at the reaction temperature for 5 to 20 minutes before the coinitiator is added.

Specifically, in the above preparation method, the system is polymerized for 5 to 30 minutes before adding the second portion of the first monomer.

Specifically, in the above preparation method, the second portion of the first monomer is added and the polymerization reaction is continued for 60 to 120 minutes before adding the end-capping agent.

Specifically, in the above preparation method, after adding the end-capping agent, the reaction is continued for 30 to 120 minutes before adding the regulating agent.

Specifically, in the above preparation method, after adding the regulator, the reaction is continued for 5 to 30 minutes before adding the second monomer.

Specifically, in the above preparation method, after the second monomer is added, the reaction is continued for 5 to 120 minutes before terminating the reaction by adding methanol.

Specifically, in the above preparation method, the conversion rate of the first monomer is 95-100%.

Specifically, in the above preparation method, the conversion rate of the second monomer is 10-70%.

The second technical problem to be solved by the present invention is to provide a polyisobutylene-based copolymer prepared by the above preparation method.

Furthermore, in the polyisobutylene-based copolymer, the number average molecular weight of the copolymer is 1000 to 5×10 ⁵ g/mol, and the molecular weight distribution is 1.01 to 1.30.

Furthermore, in the polyisobutylene-based copolymer, the mass fraction of the second monomer is 1 to 50 wt %, the conversion rate of the first monomer is 95 to 100%, and the conversion rate of the second monomer is 10 to 70%.

The third technical problem to be solved by the present invention is to provide a polymer obtained by cross-linking the above polyisobutylene copolymer. The cross-linking conditions are heating at 150-300°C for 5-60 minutes.

The present invention prepares a polyisobutylene-based block copolymer that is thermally crosslinkable, has a regular structural sequence, controllable block content, and controllable molecular weight through living/controllable cationic polymerization, wherein polyisobutylene (PIB) is a soft segment and poly-4-vinylbenzocyclobutene (P-4VBCB) is a hard segment. The method of the present invention can well control the molecular weight and soft and hard segment ratio of the polyisobutylene-based block copolymer, and the polymer molecular weight distribution is narrow. The method of the present invention has the advantages of high monomer conversion rate and yield. The copolymer prepared by the method of the present invention has a controllable molecular weight, crosslinker content, and ordered structure, which greatly improves the yield and mechanical properties. It can be widely used in biomedicine, tire inner tubes, medical packaging, wires, cables, tapes, hoses, various mechanical products, vibration isolation parts, waterproof sheets for construction, sealing and caulking materials, chewing gum, etc.

Description of the drawings:

FIG1 is a schematic diagram of the structure of the block copolymer prepared using three different initiators.

Figure 2 is a H NMR spectrum of the final product, the triblock copolymer, of Example 2. The mass fraction of the second monomer in the polymer can be calculated using the integral values of the main characteristic peaks in this figure. The calculation method is as follows:

A/4*130.19/(A/4*130.19+B/6*56)*100, where A and B refer to the integrated areas of characteristic peaks.

The calculated mass fraction of the second monomer in the final product is 9.81%.

FIG3 is a hydrogen NMR spectrum of the final product of the comparative example, and the mass fraction of the second monomer is also calculated to be 1.61%.

Figure 4 shows the differential index (RI) spectra of the first monomer of the triblock copolymer described in Example 2 at various reaction times. All elution curves show a normal distribution with no tailing. Furthermore, the peak time shifts earlier with increasing reaction time, indicating a continuous increase in molecular weight. This clearly demonstrates a living/controlled polymerization.

Figure 5 shows the differential index (RI) spectra of the second monomer of the triblock copolymer described in Example 2 at various reaction times. All elution curves show a normal distribution with no tailing. Furthermore, the peak time shifts earlier with increasing reaction time, indicating a continuous increase in molecular weight. This clearly demonstrates a living/controlled polymerization.

Figure 6 is the SEC-MALS-UV-RI spectrum of the final triblock copolymer described in Example 2. The UV, differential, and laser peak times are completely consistent, demonstrating high block efficiency and a uniform block structure between the second monomer and the first monomer.

Figure 7 compares the DSC spectra of the final products of Example 2 and the comparative example. The DSC spectra clearly show that the final product of the comparative example exhibits only a single glass transition temperature (Tg), while the final product of Example 2 exhibits two distinct Tgs, corresponding to the Tgs of the respective homopolymers of the two segments. This demonstrates that the copolymer prepared according to the present invention possesses a well-defined block structure and combines the properties of both homopolymer segments.

Figure 8 compares the mechanical properties of the products of Examples 1, 2, and 3 and the comparative example after thermal crosslinking. It is apparent from the figure that the maximum tensile strength and elongation at break of the products of the examples are significantly greater than those of the comparative example. When testing the mechanical properties of the examples and comparative examples, the copolymers formed into films after thermal crosslinking were cut into dumbbell-shaped strips according to the ASDM D-412 test standard. Three strips were taken from each sample, and the results were averaged.

DETAILED DESCRIPTION

It is well known in the professional field that in order to achieve high-efficiency block polymerization of multiple monomers in cationic polymerization, the reactivity between the monomers must be similar. For example, the reactivity of IB is similar to that of styrene (St) monomers. Therefore, when preparing IB and St block copolymers, a simple sequential monomer addition method can achieve cationic active/controlled polymerization. However, compared to St, 4VBCB is a monomer with a fused ring structure with an additional four-membered ring on the benzene ring. In a fused ring structure, due to the increased number of rings, electrons can be distributed among more atoms, which may lead to electron density concentration in certain areas. Due to the complexity of its structure and electron distribution, it may show higher reactivity in specific locations, resulting in the high reactivity of 4VBCB. At the same time, the inventors have also specifically verified through experiments that the reactivity of 4VBCB is higher than that of IB. Conventional reactions cannot introduce more 4VBCB, thereby making the resulting copolymer have higher mechanical properties. It can be seen that based on the huge differences in monomer chemical structure, reactivity, polymerization rate, etc. between IB and 4VBCB, it is very difficult to achieve active/controlled cationic polymerization and thus obtain a regular block copolymer by simply adding monomers in a sequential manner.

The inventors have discovered that, through a living/controlled cationic polymerization method, polymerization of the first monomer (IB) is initiated. After the first monomer is largely converted, a capping agent is added to cap the end of the first monomer to obtain a stable PIB + active center. A modifier is then added to adjust the Lewis acidity and reactivity of the active center, thereby reducing the chain growth rate of the second monomer to less than the chain initiation rate. The second monomer is then added to react, achieving efficient block formation. Furthermore, by controlling the reaction time of the second monomer, the crosslinker content and molecular weight of the copolymer can be easily controlled. After terminating the reaction, a block copolymer with an orderly structure is obtained. This shows that the method of the present invention can introduce more second monomers, resulting in a higher crosslinker content in the product, and thus better mechanical properties of the resulting copolymer after crosslinking.

Specifically, the preparation method of the polyisobutylene-based copolymer of the present invention comprises the following steps: first, baking and exhausting glassware to remove water and oxygen, then placing it in an inert atmosphere glove box, cooling it to a reaction temperature of -50 to -100°C, sequentially adding solvent A and solvent B, thoroughly mixing and precooling for 5 to 20 minutes, continuously adding a proton scavenger, a main initiator, and the first portion of the first monomer IB, thoroughly mixing and precooling for 5 to 20 minutes, adding a co-initiator, polymerizing for 5 to 30 minutes, adding the second portion of the first monomer IB, continuing the polymerization for 60 to 120 minutes, adding a capping agent, adding a regulator after 30 to 120 minutes, adding a mixture of the second monomer 4VBCB and solvent B after 5 to 30 minutes, continuing the polymerization for 5 to 120 minutes, and then adding methanol to terminate the reaction, precipitating the product with isopropanol, dissolving it with cyclohexane, repeatedly washing it, and drying it to obtain the copolymer.

In the present method, the first monomer IB is added in two stages, with the first portion comprising 5-30% by weight of the total first monomer, and the second portion comprising 70-95% of the total first monomer. Initially adding a small amount of the first monomer to form a stable active center, followed by a larger amount of the first monomer to initiate chain growth, avoids concentrated heat release during initiation, which can lead to side reactions such as chain transfer.

In the method of the present invention, the combined mass fraction of the first and second monomers in the reaction system is preferably controlled to be 10-50%. Controlling the concentrations of the first and second monomers within this range can control the degree of heat release and facilitate polymerization. The reaction system is the total mass of the entire system. The first and second monomers can be added in amounts as they are added directly.

In the method of the present invention, the molecular weight of the copolymer can be controlled by the ratio of the monomer to the initiator; at the same time, the longer the polymerization time of the second monomer and the higher the second monomer content, the greater the molecular weight of the copolymer.

In the method of the present invention, the reaction temperature of the entire system is controlled at -50 to -100° C., preferably -80° C. Once the temperature is determined, it is preferably maintained at this temperature throughout the polymerization process, so each addition preferably includes a pre-cooling step.

In the method of the present invention, when the main initiator is When the main initiator is When the main initiator is 2-chloro-2,4,4-trimethylpentane (TMPCl), the obtained polyisobutylene-based copolymer is a three-arm star block copolymer, and all three arms are PIB-b-P4VBCB, and the structural schematic diagram is shown in Figure 1; when the main initiator is 2-chloro-2,4,4-trimethylpentane (TMPCl), the obtained polyisobutylene-based copolymer is a diblock copolymer PIB-b-P4VBCB (polyisobutylene-b-polytetravinylphenylpropylcyclobutene), and the structural schematic diagram is shown in Figure 1.

In the method of the present invention, the first monomer conversion rate is preferably controlled to be 95-100%, that is, 95-100% of the added first monomer participates in the reaction and becomes part of the copolymer. The second monomer conversion rate is preferably controlled to be 10-70%, that is, 10-70% of the added second monomer participates in the reaction and becomes part of the copolymer.

The polyisobutylene-based copolymer prepared by the method of the present invention has a number average molecular weight of 1000-5×10 ⁵ g/mol and a molecular weight distribution of 1.01-1.30.

In the polyisobutylene-based copolymer prepared by the method of the present invention, the mass fraction of the second monomer is 1 to 50 wt%, that is, the content of the second monomer block in the final polyisobutylene-based copolymer is 1 to 50 wt%.

The polyisobutylene-based copolymer prepared by the method of the present invention has excellent mechanical properties and other effects after being heated at 150-300° C. for 5-60 minutes and thermally cross-linked in a flat-plate vulcanizer.

Example 1 Synthesis of diblock copolymer PIB-b-P4VBCB (polyisobutylene-b-polytetravinylphenylpropylcyclobutene)

The cooling liquid was injected into the cold trap of the anhydrous and oxygen-free glove box and cooled to -80 °C. A dried polymerization bottle that had been baked and evacuated was placed in it, and 1 L of a 60/40 volume ratio of methylcyclohexane/chloromethane mixed solvent was added. After mixing evenly, the mixture was precooled for 10 min. 0.143 mL of a proton scavenger 2,6-di-tert-butylpyridine, 0.64 mL of a main initiator 2-chloro-2,4,4-trimethylpentane (TMPCl), and 5.6 mL of IB ₁ were added in sequence. After precooling for 10 min, 7.0 mL of a co-initiator titanium tetrachloride was added. After 20 min of polymerization, 50 mL of IB ₂ was added and the polymerization was continued for 80 min. 0.15 mL of a capping agent 1,1-di-p-tolylethylene (DTE) was added. After 60 min, a regulator titanium isopropoxide (Ti(OiPr) ₄ ) was added. ) 5.4mL, and after 10 minutes, 25mL of the second monomer, 4-vinylbenzocyclobutene (4VBCB), was added. Polymerization continued for 30 minutes before methanol was added to terminate the reaction. The product was precipitated with isopropanol and then dissolved in cyclohexane, repeating this process three times before drying. 8g of the dried product was thermally crosslinked in a flat-plate vulcanizer at 200°C for 25 minutes to form a mold.

Example 2 Synthesis of triblock copolymer P4VBCB-b-PIB-b-P4VBCB (poly(4-vinylbenzocyclobutene-b-polyisobutylene-b-polytetravinylphenylcyclobutene))

Pour coolant into the cold trap of the anhydrous and oxygen-free glove box and cool it to -80°C. Place a dried polymerization bottle that has been baked and evacuated, add 1 L of a 60/40 volume ratio of methylcyclohexane/chloromethane mixed solvent, mix well, and precool for 10 minutes. Add 0.143 mL of a proton scavenger 2,6-di-tert-butylpyridine, 0.79 g of a primary initiator 5-tert-butyl-1,3-di(methylethylchloro)benzene, and 5.6 mL of IB ₁ in sequence. After precooling for 10 minutes, add 7.0 mL of a co-initiator, titanium tetrachloride. After 20 minutes of polymerization, add 50 mL of IB _2. Take 1 mL of sample at 25, 50, 60, 70, and 90 minutes of polymerization, respectively, and terminate with methanol. After 100 minutes of polymerization, 0.15 mL of the end-capping agent 1,1-di-p-tolylethylene (DTE) was added. After 60 minutes, 5.4 mL of the modifier titanium isopropoxide (Ti(OiPr) ₄ ) was added. After 10 minutes, 25 mL of the second monomer, 4-vinylbenzocyclobutene (4VBCB), was added. Samples of 1 mL were taken at 5, 10, 20, 30, 40, and 50 minutes, and terminated with methanol. Methanol was added after 60 minutes of polymerization to terminate the reaction. The product was precipitated with isopropanol and dissolved in cyclohexane three times before drying. The final product was weighed to 62.4 g, with an overall yield (total monomer weight/final copolymer weight) of 94.5%. The product was then placed in a platen curing apparatus and thermally crosslinked at 240°C for 5 minutes.

Example 3 Synthesis of three-arm star block copolymer (PIB-b-P4VBCB) ₃ (polyisobutylene-b-polytetravinylphenylcyclobutene) ₃

Pour coolant into the cold trap of the anhydrous and oxygen-free glove box and cool it to -80°C. Place a dried polymerization bottle that has been baked and evacuated, add 1 L of a 60/40 volume ratio of methylcyclohexane/chloromethane mixed solvent, mix well, and precool for 10 minutes. Then, add 0.143 mL of a proton scavenger 2,6-di-tert-butylpyridine, 0.85 g of a primary initiator 1,3,5-tris(methylethylchloro)benzene, and 5.6 mL of IB ₁ in sequence. After precooling for 10 minutes, 7.0 mL of a co-initiator, titanium tetrachloride, is added. After 20 minutes of polymerization, 50 mL of IB ₂ is added and the polymerization is continued for 80 minutes. 0.15 mL of a capping agent 1,1-di-p-tolylethylene (DTE) is added. After 60 minutes, 6.8 mL of a regulator, titanium isopropoxide (Ti(OiPr) ₄ ), is added. After 15 minutes, 32 mL of a second monomer, 4-vinylbenzocyclobutene (4VBCB), is added. The polymerization is continued for 30 minutes and methanol is added to terminate the reaction. The product was precipitated with isopropyl alcohol and then dissolved with cyclohexane, and the process was repeated three times before drying. 8 g of the dried product was placed in a flat plate vulcanizer at 240°C for 6 minutes for thermal cross-linking to form a film.

Comparative Example

A coolant was pumped into a cold trap in an anhydrous and oxygen-free glove box and cooled to -80°C. A dried, oven-dried polymerization flask was placed in it, followed by 1 L of a 60/40 (volume) mixture of methylcyclohexane and methyl chloride. Mixed thoroughly, the mixture was pre-cooled for 10 minutes. Then, 0.143 mL of the proton scavenger 2,6-di-tert-butylpyridine, 0.79 g of the primary initiator 5-tert-butyl-1,3-di(methylethylchloro)benzene, and 5.6 mL of IB ₁ were added. After pre-cooling for 10 minutes, 7.0 mL of the co-initiator titanium tetrachloride was added. After 20 minutes of polymerization, 50 mL of IB ₂ and 25 mL of the second monomer, 4-vinylbenzocyclobutene (4VBCB), were added. After 60 minutes of polymerization, methanol was added to terminate the reaction. The product was precipitated with isopropanol and dissolved in cyclohexane. This process was repeated three times before drying. The final product, 16.7 g, was weighed, yielding 25.3%. The product was then placed in a flat plate vulcanizer and thermally crosslinked at 240°C for 5 min.

Claims (10)

The preparation method of a polyisobutylene-based copolymer comprises the following steps: firstly initiating polymerization of a first monomer IB through living/controllable cationic polymerization, then adding a capping agent to cap the first monomer to obtain a stable PIB+active center, then adding a regulator to adjust the Lewis acidity and reaction activity of the system; then adding a second monomer 4-VBCB to continue the polymerization reaction, terminating the reaction, and performing post-treatment to obtain the polyisobutylene-based copolymer. The method for preparing a polyisobutylene-based copolymer according to claim 1 comprises the following steps: subjecting a proton scavenger, a main initiator, a first part of a first monomer IB, and a co-initiator to a polymerization reaction in a solvent, then adding a second part of the first monomer IB and continuing the polymerization reaction until the first monomer conversion rate is above 95%; then adding a capping agent for end-capping to obtain a stable PIB+ active center, then adding a regulator to adjust the Lewis acidity and reaction activity of the system; then adding a second monomer 4-VBCB and continuing the polymerization reaction, terminating the reaction, and obtaining the polyisobutylene-based copolymer through post-treatment. The preparation method according to claim 1 or 2, characterized in that the end-capping agent is at least one of 1,1-diphenylethylene, 1,1-di-p-tolylethylene, 2-methylfuran, and 2-tert-butylfuran; preferably, the end-capping agent is 1,1-diphenylethylene or 1,1-di-p-tolylethylene. The preparation method according to any one of claims 1-3, characterized in that the regulator is at least one of Ti(OR) ₄ , SnBr ₄ , SnCl ₄ , n-Bu ₄ NCl, and BCl ₃ , wherein R is a C _1-4 alkyl group; preferably, the regulator is titanium isopropoxide or Bu ₄ NCl. The preparation method according to any one of claims 1 to 4, characterized in that at least any one of the following is satisfied: The main initiator is Chloro-2,4,4-trimethylpentane; wherein R ₁ is methyl, Cl or methoxy, and R ₂ and R ₃ are each independently Cl or methoxy; The co-initiator is at least one of titanium tetrachloride, ferric chloride, boron trifluoride, boron trichloride, gallium trichloride, aluminum chloride, and alkyl aluminum chloride; preferably, the co-initiator is titanium tetrachloride; The proton scavenger is at least one of 2,6-di-tert-butylpyridine, 2,6-di-tert-butyl-4-methylpyridine, and 2,4,6-tri-tert-butylpyridine; preferably, the proton scavenger is 2,6-di-tert-butylpyridine; The solvent is a mixed solvent of solvent A and solvent B; wherein solvent A is at least one of chloromethane, dichloromethane, and chloroform, and solvent B is at least one of n-hexane, cyclohexane, and methylcyclohexane; further, the volume ratio B/A of the mixed solvent is 7:3, 6:4, or 5:5. The preparation method according to any one of claims 1 to 5, characterized in that at least any one of the following is satisfied: The molar ratio of the first monomer to the second monomer is (60-99):(40-1); The molar ratio of the main initiator to the first monomer is 1:(50-1000); The molar ratio of the main initiator to the co-initiator is 1:(2-64); The molar ratio of the end-capping agent to the main initiator is 1:(1-10); The molar ratio of the regulator to the end-capping agent is (1-64):1; The molar ratio of the proton scavenger to the end-capping agent is 1:(1-10); The first part of the first monomer accounts for 5 to 30 wt% of the total amount of the first monomer, and the second part of the first monomer accounts for 70 to 95 wt% of the total amount of the first monomer; The mass fraction of the total mass of the first monomer and the second monomer in the reaction system is 10 to 50%. The preparation method according to any one of claims 1 to 6, characterized in that each reaction temperature is -50 to -100°C, preferably -80°C. The preparation method according to any one of claims 1 to 7, characterized in that at least any one of the following is satisfied: the solvent is pre-cooled at the reaction temperature for 5 to 20 minutes before the proton scavenger, the main initiator, and the first portion of the first monomer are added; after the proton scavenger, the main initiator, and the first portion of the first monomer are added to the solvent, the entire system is pre-cooled at the reaction temperature for 5 to 20 minutes before the coinitiator is added; The system is polymerized for 5 to 30 minutes before adding the second portion of the first monomer; Add the second portion of the first monomer and continue the polymerization reaction for 60 to 120 minutes before adding the end-capping agent; After adding the end-capping agent, continue the reaction for 30 to 120 minutes before adding the regulator; After adding the regulator, continue the reaction for 5 to 30 minutes before adding the second monomer; After adding the second monomer, the reaction is continued for 5 to 120 minutes and then terminated; The second monomer conversion rate is 10-70%. A polyisobutylene-based copolymer prepared by the preparation method according to any one of claims 1 to 8. The polyisobutylene-based copolymer according to claim 9, characterized in that: the number average molecular weight is 1000 to 5×10 ⁵ g/mol, and the molecular weight distribution is 1.01 to 1.30; Furthermore, the mass fraction of the second monomer is 1 to 50 wt%.