A high molecular weight polyisobutylene with unimodal / bimodal distribution and preparation method thereof

Abstract

A high-molecular-weight polyisobutylene with a unimodal / bimodal molecular weight distribution and its preparation method are disclosed, belonging to the field of polymer compound preparation. This preparation method utilizes a simple initiator and co-initiator system to produce a high-molecular-weight polyisobutylene with a unimodal / bimodal molecular weight distribution. Specifically, by using a readily available initiator and a Lewis acid, which is relatively less corrosive to equipment, as a co-initiator, at relatively high temperatures (-60°C to -90°C), simple adjustments to the initiator substituents, and process optimization, a high-molecular-weight polyisobutylene with a weight-average molecular weight range of 69.69×10 4 ~275.8×10 4 High molecular weight polyisobutylene with monomodal / bimodal distribution of g / mol.

Description

Technical Field

[0001] The invention belongs to the field of polymer compound preparation, and particularly relates to high molecular weight polyisobutylene with unimodal / bimodal distribution and a preparation method thereof. Background Art

[0002] Polyisobutylene (PIB) is categorized by molecular weight into low, medium, and high molecular weight PIB. High molecular weight PIB is generally defined as having a number average molecular weight (Mn) greater than 100,000. Due to its excellent low fragility, airtightness, and thermal stability, it is used in the manufacture of tire innerliners, cable insulation, and thermal and soundproof building materials. PIB polymerization is a typical cationic polymerization, with highly reactive active centers. Industrially, high molecular weight polyisobutylene (HPIB) is primarily produced using strong Lewis acids such as boron trifluoride or aluminum trichloride as a co-initiator system. The polymerization reaction is performed at an extremely low polymerization temperature (Tp) to suppress chain transfer and termination reactions. However, due to the complex preparation process and high equipment costs, its production and application are significantly limited. This has led to long-term high prices for high molecular weight PIB products, significantly increasing the production costs of downstream products.

[0003] Representative patent CN104136470B uses a Lewis acid complex of BF3, iron halide, AlCl3 or alkylaluminum halide, or a Lewis acid combined with an organic sulfonic acid initiator as a polymerization catalyst, plus at least one reaction promoter and at least one chain length regulator, and adopts the "BASF belt" polymerization process to prepare unimodal high molecular weight polyisobutylene with a molecular weight of 75,000 to 10,000,000 g / mol, usually at -80°C to -190°C.

[0004] High molecular weight rubber can impart better physical and mechanical properties to materials, but higher molecular weight results in poorer processing properties. To improve processing properties, researchers often introduce a low molecular weight peak or "shoulder" through physical blending or chemical methods to create a bimodal distribution. This acts as a plasticizer, imparting good processing properties to the material.

[0005] No patents have yet been found for high-molecular-weight polyisobutylene with a bimodal distribution. Related patents exist for other similar materials with bimodal distributions. Patent CN112011018B synthesizes a poly(styrene-conjugated diene) block polymer, which is then coupled with silicon tetrachloride and reacted with HCl gas to produce a functionalized four-arm star-branched agent containing silicon and chlorine. A bimodal star-branched butyl rubber is synthesized at -60-100°C using the star-branched agent, a primary initiator, and a co-initiator. Patent CN107344982B utilizes two loop reactors connected in series, initially conducting a polymerization reaction in the first loop reactor zone to produce a first butyl rubber slurry. This first butyl rubber slurry is then fed into a second loop reactor zone for further polymerization, ultimately producing butyl rubber with a broad / bimodal molecular weight distribution. Patent CN112142892B prepares bimodal polyisoprene by reacting one rare earth catalyst for a period of time before adding another rare earth catalyst.

[0006] In the polymerization of high molecular weight polyisobutylene, the strong Lewis acid boron trifluoride and aluminum trichloride as co-initiators may cause corrosion to the equipment during use, leading to increased equipment maintenance costs; ultra-low temperature reactions will result in a large amount of energy consumption.

[0007] In terms of high molecular weight rubber with bimodal distribution, the preparation of star-shaped branching agents, the use of two loop reactors in series, or the addition of two catalysts at intervals have the disadvantages of requiring the introduction of other components, more processes, relatively complex and high-consumption processes, and unclear bimodal structure.

[0008] Based on this, the present invention addresses the current issues of strong Lewis acid corrosion on equipment and the significant energy consumption caused by ultra-low temperatures. Using a relatively less corrosive Lewis acid as a co-initiator alleviates equipment corrosion during the reaction and reduces equipment maintenance costs. High-molecular-weight polyisobutylene is produced at relatively high temperatures (e.g., -60°C to -90°C). Furthermore, through a relatively simple initiation system with a few components and a straightforward process flow, high-molecular-weight polyisobutylene products with unimodal or bimodal distributions can be obtained as desired, improving product processing performance and increasing product diversity. Summary of the Invention

[0009] The present invention primarily addresses the shortcomings of existing technologies, such as the corrosive effects of strong Lewis acids on equipment, the significant energy consumption caused by ultra-low temperatures, the poor processing properties of unimodal high-molecular-weight polyisobutylene, and the complex processes involved in synthesizing bimodal high-molecular-weight products. By providing a high-molecular-weight polyisobutylene with a unimodal / bimodal distribution and a method for its preparation, the present invention utilizes a readily available initiator system and a Lewis acid, which is relatively less corrosive to equipment, as a co-initiator system. A weight-average molecular weight (Mw) of 69.69×10-10 can be obtained at relatively high temperatures (-60°C to -90°C) through simple adjustments to the initiator substituents and process optimization. 4 ~275.8×10 4 High molecular weight polyisobutylene with monomodal / bimodal distribution of g / mol.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] The present invention provides a method for preparing high molecular weight polyisobutylene with a unimodal / bimodal distribution. The method employs an initiator and a co-initiator as a catalytic system, and uses isobutylene as a monomer to polymerize to obtain high molecular weight polyisobutylene with a unimodal or bimodal distribution. High molecular weight polyisobutylene with a bimodal distribution is more preferred.

[0012] The initiator of the high molecular weight polyisobutylene with unimodal / bimodal distribution is selected from the following: benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenyl ethyl ether, dibenzyl ether, benzyl chloride, benzyl bromide, α,α'-dichloro-p-xylene, benzoyl chloride, 4-fluorobenzoyl chloride, ethyl benzoate, methyl benzoate, ethyl phenylacetate, ethyl 4-chlorobenzoate, methyl 4-fluorobenzoate, methyl 4-chlorobenzoate, ethyl p-fluorobenzoate, 2-(chloromethyl)naphthalene, ethyl pentafluorobenzoate, 4-methylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-tert-butylbenzyl alcohol, benzyl phenyl ether, 2-(p-tolyl)propan-2-ol, 2-(4-methoxyphenyl)propan-2-ol One or more of: -2-ol, 2-(4-chlorophenyl)propan-2-ol, 4-methylbenzyl bromide, 2,4-dimethylbenzyl bromide, 4-tert-butylbenzyl bromide, 2,6-dimethylbenzyl chloride, 2,4,6-trimethylbenzyl chloride, 4-tert-butylbenzyl chloride, 4-methoxybenzyl chloride, 3-methoxybenzyl chloride, triphenylmethane, methyl p-methylbenzoate, methyl 4-tert-butylbenzoate, methyl 4-methoxybenzoate, methyl 4-(dimethylamino)benzoate, ethyl 1-naphthoate, tert-butyl benzoate, ethyl 2,6-dimethylbenzoate, ethyl p-methoxybenzoate, diethyl terephthalate, ethyl 4-dimethylaminobenzoate, and benzyl benzoate.

[0013] The co-initiator for the high molecular weight polyisobutylene with unimodal / bimodal distribution is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, ethylaluminum dichloride, and dichloroisobutylaluminum.

[0014] Preferably, when the initiator is selected from one or more of benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenyl ethyl ether, benzyl chloride, benzyl bromide, α,α'-dichloro-p-xylene, benzoyl chloride, 4-fluorobenzoyl chloride, ethyl benzoate, methyl benzoate, ethyl phenylacetate, ethyl 4-chlorobenzoate, methyl 4-fluorobenzoate, methyl 4-chlorobenzoate, ethyl p-fluorobenzoate, 2-(chloromethyl)naphthalene, and ethyl pentafluorobenzoate, a high molecular weight polyisobutylene with a unimodal distribution is obtained; when the initiator is selected from 4-methylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-tert-butylbenzyl alcohol, benzyl phenyl ether, dibenzyl ether, 2-(p-tolyl)propan-2-ol, 2-(4-methoxybenzyl)propan-2-ol, The invention relates to one or more of the following: 1,4-dimethylbenzyl bromide, 2,4-dimethylbenzyl bromide, 4-tert-butylbenzyl bromide, 2,6-dimethylbenzyl chloride, 2,4,6-trimethylbenzyl chloride, 4-tert-butylbenzyl chloride, 3-methoxybenzyl chloride, triphenylmethane, methyl p-methylbenzoate, methyl 4-tert-butylbenzoate, methyl 4-methoxybenzoate, methyl 4-(dimethylamino)benzoate, ethyl 1-naphthoate, tert-butyl benzoate, ethyl 2,6-dimethylbenzoate, ethyl p-methoxybenzoate, diethyl terephthalate, ethyl 4-dimethylaminobenzoate and benzyl benzoate, and the obtained polyisobutylene has a bimodal distribution and a high molecular weight.

[0015] The method for preparing a high molecular weight polyisobutylene with a unimodal / bimodal distribution of the present invention more specifically comprises the following steps:

[0016] S1: Prepare ingredients:

[0017] The polymerization reaction system is an anhydrous and oxygen-free inert gas environment, and the solvent after dehydration and deoxygenation, the monomer after dehydration and deoxygenation, the initiator, and the co-initiator are all stored in an inert environment;

[0018] S2: Aggregation:

[0019] An initiator is added to the low-temperature constant-temperature reactor, and the low-temperature constant-temperature reactor is replaced with an anhydrous and oxygen-free inert gas environment. A solvent and a monomer are added, and the temperature of the low-temperature constant-temperature reactor is equilibrated for 20 minutes to obtain a polymerization system. A co-initiator is added to initiate the polymerization reaction. After the polymerization is completed, a terminator is added to terminate the polymerization reaction to obtain a polymer product.

[0020] S3: Post-processing:

[0021] After removing unreacted monomers and solvent from the polymerization product, the product is soaked in ethanol and then dried to obtain high molecular weight polyisobutylene with unimodal / bimodal distribution.

[0022] In the above-mentioned S1, the solvent is selected from one or more of n-hexane, tetrahydrofuran, methyl chloride, dichloromethane, toluene, ethyl chloride, vinyl chloride, and propane.

[0023] In the above-mentioned S1, the inert gas is preferably nitrogen or argon.

[0024] In the S2, the inert gas is nitrogen or argon.

[0025] In the polymerization system, the mass concentration of isobutylene (IB) monomer is 5 wt % to 50 wt %.

[0026] The molar ratio of the initiator to the co-initiator is: (0.01-1):1.

[0027] The mass percentage of the co-initiator to the monomer is 0.02 to 10 wt %.

[0028] The equilibrium temperature of the low-temperature constant-temperature reactor is -60℃~-90℃.

[0029] The polymerization time is 5 to 60 minutes.

[0030] The coinitiator is added in the following manner: when there is only one coinitiator, it is slowly added dropwise at a rate of 0.5 to 2 mL / min; when there are two or more coinitiators, the two coinitiators are slowly added dropwise in sequence with an interval of 0 to 45 minutes; the addition rate is 0.5 to 2 mL / min.

[0031] The terminator is selected from one of water, anhydrous methanol, anhydrous ethanol or an ethanol / water mixed solution containing 1wt% NaOH; in the ethanol / water mixed solution, the volume ratio of ethanol:water is 1:1; the amount of the terminator used accounts for 1-5% of the volume percentage of the polymerization system.

[0032] In the above-mentioned S3, the method for removing unreacted monomers and solvent is evaporation under reduced pressure.

[0033] In the above-mentioned S3, the ethanol soaking time is more than 12 hours.

[0034] In the above-mentioned S3, the process parameters of drying are: pressure -0.1 MPa, 40-50° C. and drying to constant weight.

[0035] The high molecular weight polyisobutylene with unimodal / bimodal distribution of the present invention is prepared by the above preparation method with a yield of 50% to 99%. When the high molecular weight polyisobutylene with unimodal distribution is prepared, the weight average molecular weight range is 69.69×10 4 ~275.8×104 g / mol, and the molecular weight distribution (PDI) is 2.06~7.00; when the bimodal distribution high molecular weight polyisobutylene is prepared, the weight average molecular weight range of the high molecular weight part is 112.14×10 4 ~250.40×10 4 g / mol, the molecular weight distribution (PDI) is 1.96~3.11; the weight average molecular weight range of the low molecular weight part is 3.28×10 4 ~16.50×10 4 g / mol, and the molecular weight distribution (PDI) is 1.29~1.96.

[0036] The high molecular weight polyisobutylene with unimodal / bimodal distribution and the preparation method thereof of the present invention have the following beneficial effects:

[0037] (1) By using a simple and readily available initiation system and a Lewis acid with relatively weak corrosion to equipment as a co-initiation system, at a relatively high temperature (-60℃~-90℃), through simple substituent adjustment and process optimization, a weight-average molecular weight range of 69.69×10 4 ~275.8×10 4 g / mol, the molecular weight distribution (PDI) is 2.06~7.00, and the weight average molecular weight range of high molecular weight polyisobutylene or high molecular weight part is 112.14×10 4 ~250.40×10 4 g / mol, the molecular weight distribution (PDI) is 1.96~3.11; the weight average molecular weight range of the low molecular weight part is 3.28×10 4 ~16.50×10 4 g / mol, high molecular weight polyisobutylene with a bimodal molecular weight distribution (PDI) of 1.29~1.96.

[0038] (2) The synthesis of high molecular weight polyisobutylene requires the interaction between the initiator and the co-initiator to form a controlled ion pair to achieve controlled polymerization. The product unimodal / bimodal distribution can be adjusted by inhibiting / controlling the occurrence of chain transfer. By simply changing the structure of the initiator, a bimodal structure can be obtained that maintains material properties while improving processability.

[0039] (3) The process flow of the present invention is simple and can shorten the reaction cycle; the mild conditions can effectively save raw material costs and reduce energy consumption; and the bimodal structure of the product can be controlled, effectively improving product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 GPC test curves of high molecular weight polyisobutylene prepared in Examples 1-3.

[0041] Figure 2 GPC test curves of high molecular weight polyisobutylene prepared in Examples 4-7. DETAILED DESCRIPTION

[0042] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0043] In the following examples, the preparation method of high molecular weight polyisobutylene with unimodal / bimodal distribution is as follows:

[0044] Pre-experimental treatment: All polymerization reactions were carried out under nitrogen or argon atmosphere. Double-row tubing was used to ensure an inert environment for the reaction system. Solvents and isobutylene (IB) monomer were dehydrated and deoxygenated under certain conditions. They were also stored in an inert environment with the initiator and co-initiator to strictly ensure that the system was free of water and oxygen.

[0045] The solvent used is a mixture of one or more of n-hexane, tetrahydrofuran, methyl chloride, dichloromethane, toluene, ethyl chloride, vinyl chloride and propane.

[0046] The general polymerization procedure is as follows: First, add a predetermined amount of initiator to a Schlenk reaction tube, connect the double-row tube, replace the inert gas three times, and then place it in a low-temperature constant-temperature reactor. While ensuring a sufficient inert gas flow rate, use a syringe with a long needle or a feed kettle that has replaced the inert gas three times to add the solvent and monomer to the reaction tube in sequence. The temperature is then equilibrated for 20 minutes. One or two co-initiators are added using a specific addition method to initiate the reaction. After the set polymerization time, a terminator is added to terminate the reaction.

[0047] The inert environment is nitrogen or argon.

[0048] The isobutylene (IB) monomer concentration is 5 wt% to 50 wt%.

[0049] The molar ratio of the initiator to the co-initiator is (0.01-1):1.

[0050] The mass percentage of the co-initiator to the monomer is 0.02-10wt%.

[0051] The polymerization time is 5 to 60 minutes.

[0052] The co-initiators are added in the following manner: one co-initiator is directly and slowly added dropwise, and the two co-initiators are added dropwise in sequence with an interval of 0-45 minutes.

[0053] The low-temperature constant-temperature reactor is set at a temperature of -60°C to -90°C.

[0054] The terminator is one of water, anhydrous methanol, anhydrous ethanol, or an ethanol / water (V / V=1) mixed solution containing 1 wt% NaOH. The amount of the terminator used is generally 1-5% (V / V) of the polymerization system.

[0055] General post-processing procedures: After removing unreacted monomers and solvent from the polymerized product by evaporation under reduced pressure, the product was washed and soaked in ethanol for 12 hours. The product was then dried to constant weight at -0.1 MPa and 40°C. The yield was calculated, and the molecular weight and distribution were determined using gel permeation chromatography (GPC).

[0056] The yield of the present invention is calculated by weighing: Yield (%) = PIB polymer mass (g) / IB monomer mass (g).

[0057] Molecular weights were determined using GPC (Gel Permeation Chemistry) using polystyrene (PS) as the GPC standard and tetrahydrofuran (THF) as the solvent. The polymer sample was prepared into a 1 mg / mL solution. Measurements were performed at a flow rate of 1 mL / min and a column temperature of 35°C to obtain average molecular weight and molecular weight distribution data. The molecular weight distribution (PDI) is calculated as follows: weight average molecular weight (Mw) of the polymer product / number average molecular weight (Mn) of the polymer product.

[0058] Example 1

[0059] The reaction temperature was set at -90°C. Under nitrogen, a 0.05 molar ratio of initiator benzyl alcohol to the co-initiator and a 30 wt% isobutylene (IB) monochloromethane solution were transferred sequentially to a Schlenk tube. After equilibrating at the temperature for 20 minutes, a 0.5 wt% ratio of co-initiator diisobutylaluminum chloride to the monomer was added to initiate the reaction. After 30 minutes of the set polymerization time, 2 mL of anhydrous ethanol was added as a terminator to terminate the reaction. The resulting polymer product was removed from the unreacted monomer and solvent, and then dried. The calculated yield was 99%. GPC analysis was performed, and the curve is shown in the figure. Figure 1 , which is a high molecular weight polyisobutylene with unimodal distribution. Mw = 69.69 × 10 4 g / mol, Mn=15.84×10 4 g / mol, molecular weight distribution (PDI) 4.39.

[0060] Example 2

[0061] The reaction temperature was set at -90°C. Under nitrogen protection, the initiator 2,6-dimethylbenzyl alcohol at a molar mass ratio of 0.05 to the co-initiator and a 30wt% isobutylene (IB) monochloromethane solution were transferred to the Schlenk tube in sequence. After 20 minutes of equilibration, the co-initiator diisobutylaluminum chloride at a mass ratio of 0.5wt% to the monomer was added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The calculated yield was 87%. GPC was used for testing, and the curve is shown in the figure. Figure 1 , which has a bimodal structure, with the high molecular weight part Mw=126.00×10 4 g / mol, Mn=40.46×10 4 g / mol, molecular weight distribution (PDI) 3.11. Low molecular weight part Mw=3.28×10 4 g / mol, Mn=2.53×10 4 g / mol, molecular weight distribution (PDI) 1.29.

[0062] Example 3

[0063] The reaction temperature was set at -90°C. Under nitrogen protection, 4-tert-butylbenzyl bromide (0.05 molar ratio of initiator to co-initiator) and a 30 wt% isobutylene (IB) monochloromethane solution were transferred to a Schlenk tube in sequence. After equilibration at the temperature for 20 minutes, diisobutylaluminum chloride (0.5 wt% of the monomer mass ratio) was added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2 mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The calculated yield was 93%. GPC was used for testing, and the curve is shown in the figure. Figure 1 , which has a bimodal structure, with the high molecular weight part Mw=112.14×10 4 g / mol, Mn=39.01×10 4 g / mol, molecular weight distribution (PDI) 2.87. Low molecular weight part Mw=3.30×10 4 g / mol, Mn=2.50×10 4 g / mol, molecular weight distribution (PDI) 1.33.

[0064] Example 4

[0065] The reaction temperature was set at -90°C. Under nitrogen protection, the initiator benzyl methyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30wt% monochloromethane solution of isobutylene (IB) were transferred to the Schlenk tube in sequence. After 20 minutes of equilibration, the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8wt% to the monomer were added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The calculated yield was 55%. GPC was used for testing, and the curve is shown in the figure. Figure 2 , which is a high molecular weight polyisobutylene with a unimodal distribution, and its Mw = 126.50×10 4 g / mol, Mn=18.10×10 4 g / mol, molecular weight distribution (PDI) 7.00.

[0066] Example 5

[0067] The reaction temperature was set at -90°C. Under nitrogen protection, the initiator benzyl ethyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30wt% isobutylene (IB) monochloromethane solution were transferred to the Schlenk tube in sequence. After 20 minutes of equilibration, the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8wt% to the monomer were added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The yield was calculated to be 50%. After GPC testing, the curve is shown in the figure. Figure 2 , is a high molecular weight polyisobutylene with a unimodal distribution, and its Mw is 140.10×10 4 g / mol, Mn=45.40×10 4 g / mol, molecular weight distribution (PDI) 3.07.

[0068] Example 6

[0069] The reaction temperature was set at -90°C. Under nitrogen protection, the initiator dibenzyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30wt% isobutylene (IB) monochloromethane solution were transferred to the Schlenk tube in sequence. After 20 minutes of equilibration, the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8wt% to the monomer were added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The calculated yield was 66%. After GPC testing, the curve is shown in the figure. Figure 2 , which has a bimodal structure, with the high molecular weight part Mw=199.20×10 4 g / mol, Mn=92.60×10 4g / mol, molecular weight distribution (PDI) 2.15. Low molecular weight part Mw=10.80×10 4 g / mol, Mn=6.70×10 4 g / mol, molecular weight distribution (PDI) 1.59.

[0070] Example 7

[0071] The reaction temperature was set at -90°C. Under nitrogen protection, the initiator benzyl phenyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30wt% isobutylene (IB) monochloromethane solution were transferred to the Schlenk tube in sequence. After 20 minutes of equilibration, the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8wt% to the monomer were added to initiate the reaction. After reaching the set polymerization time of 30 minutes, 2mL of anhydrous ethanol was added as a terminator to terminate the reaction. The polymer product was obtained, and after removing the unreacted monomer and solvent, it was dried. The calculated yield was 52%. After GPC testing, the curve is shown in the figure. Figure 2 , which has a bimodal structure, with the high molecular weight part Mw=250.40×10 4 g / mol, Mn=128.00×10 4 g / mol, molecular weight distribution (PDI) 1.96; low molecular weight part Mw = 16.50×10 4 g / mol, Mn=8.40×10 4 g / mol, molecular weight distribution (PDI) 1.96.

[0072] Example 8

[0073] The difference between Example 8 and Example 5 is that the reaction temperature of -90°C in Example 5 is changed to -75°C.

[0074] The experimental results of Example 8 showed that the yield of the polymerization product was 85%. After GPC testing, it was a high molecular weight polyisobutylene with a single peak distribution, and its Mw = 122.50 × 10 4 g / mol, Mn=19.10×10 4 g / mol, molecular weight distribution (PDI) 6.41.

[0075] Example 9

[0076] The difference between Example 9 and Example 5 is that the reaction temperature of -90°C in Example 5 is changed to -60°C.

[0077] The experimental results of Example 9 showed that the yield of the polymerization product was 74%. GPC test showed that the product was a high molecular weight polyisobutylene with a single peak distribution, and its Mw was 73.80×10 4 g / mol, Mn=33.90×10 4g / mol, molecular weight distribution (PDI) 2.17.

[0078] Example 10

[0079] The difference between Example 10 and Example 5 is that the chloromethane used in Example 5 is replaced with n-hexane as the solvent;

[0080] The experimental results of Example 10 showed that the yield of the polymerization product was 67%. GPC test showed that the product was a high molecular weight polyisobutylene with a single peak distribution, and its Mw was 153.5×10 4 g / mol, Mn=74.40×10 4 g / mol, molecular weight distribution (PDI) 2.06.

[0081] Example 11

[0082] The difference between Example 11 and Example 5 is that the polymerization time of Example 5 is changed from 30 min to 60 min;

[0083] The experimental results of Example 11 showed that the yield of the polymerization product was 100%. GPC test showed that the product was a high molecular weight polyisobutylene with a single peak distribution, and its Mw was 161.10×10 4 g / mol, Mn=51.63×10 4 g / mol, molecular weight distribution (PDI) 3.12.

[0084] Example 12

[0085] The difference between Example 12 and Example 5 is that the reaction was initiated by adding dimethylaluminum chloride 30 minutes after adding diisobutylaluminum chloride instead of adding diisobutylaluminum chloride and dimethylaluminum chloride as used in Example 5.

[0086] The experimental results of Example 12 showed that the yield of the polymerization product was 65%. GPC test showed that the product was a high molecular weight polyisobutylene with a single peak distribution, Mw = 275.80 × 10 4 g / mol, Mn=112.3×10 4 g / mol, molecular weight distribution (PDI) 2.45.

[0087] Examples 13-16

[0088] The difference between Examples 13-16 and Example 1 is that the initiator is changed from benzyl alcohol to benzyl chloride (Example 13), benzyl bromide (Example 14), 2-phenyl-2-propanol (Example 15), and benzoyl chloride (Example 16).

[0089] The experimental results of Example 13 showed that the yield of the polymerization product was 77%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 72.51×104 g / mol, Mn=26.70×10 4 g / mol, molecular weight distribution (PDI) 2.71.

[0090] The experimental results of Example 14 showed that the yield of the polymerization product was 83%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 81.30×10 4 g / mol, Mn=27.01×10 4 g / mol, molecular weight distribution (PDI) 3.01.

[0091] The experimental results of Example 15 showed that the yield of the polymerization product was 66%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 73.90×10 4 g / mol, Mn=14.50×10 4 g / mol, molecular weight distribution (PDI) 5.10.

[0092] The experimental results of Example 16 showed that the yield of the polymerization product was 52%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 79.21×10 4 g / mol, Mn=13.60×10 4 g / mol, molecular weight distribution (PDI) 5.83.

[0093] Examples 17-19

[0094] The difference from Example 2 is that the initiator is changed from 2,6-dimethylbenzyl alcohol to 4-methylbenzyl alcohol (Example 17), 2-(4-methoxyphenyl)propan-2-ol (Example 18), and 2-(4-chlorophenyl)propan-2-ol (Example 19).

[0095] The experimental results of Example 17 showed that the yield of the polymerization product was 90%. It had a bimodal structure, with the high molecular weight portion Mw = 112.30 × 10 4 g / mol, Mn=48.80×10 4 g / mol, molecular weight distribution (PDI) 2.30. Low molecular weight part Mw=11.91×10 4 g / mol, Mn=7.32×10 4 g / mol, molecular weight distribution (PDI) 1.62.

[0096] The experimental results of Example 18 showed that the yield of the polymer product was 55%. It showed a bimodal structure, with the high molecular weight portion Mw = 123.55 × 10 4 g / mol, Mn=54.82×10 4 g / mol, molecular weight distribution (PDI) 2.25. Low molecular weight part Mw=12.30×104 g / mol, Mn=8.10×10 4 g / mol, molecular weight distribution (PDI) 1.52.

[0097] The experimental results of Example 19 showed that the yield of the polymerization product was 73%. It showed a bimodal structure, with the high molecular weight portion Mw = 155.80 × 10 4 g / mol, Mn=53.71×10 4 g / mol, molecular weight distribution (PDI) 2.90. Low molecular weight part Mw=9.8×10 4 g / mol, Mn=6.9×10 4 g / mol, molecular weight distribution (PDI) 1.42.

[0098] Examples 20-23

[0099] The difference from Example 3 is that the initiator is changed from 4-tert-butylbenzyl bromide to 2,6-dimethylbenzyl chloride (Example 20), 2,4,6-trimethylbenzyl chloride (Example 21), 4-tert-butylbenzyl chloride (Example 22), and triphenylmethane chloride (Example 23).

[0100] The experimental results of Example 20 showed that the yield of the polymerization product was 88%. It showed a bimodal structure, with the high molecular weight portion Mw = 126.20 × 10 4 g / mol, Mn=58.46×10 4 g / mol, molecular weight distribution (PDI) 2.30. Low molecular weight part Mw=6.92×10 4 g / mol, Mn=5.20×10 4 g / mol, molecular weight distribution (PDI) 1.33.

[0101] The experimental results of Example 21 showed that the yield of the polymerization product was 91%. It had a bimodal structure, with the high molecular weight portion Mw = 113.28 × 10 4 g / mol, Mn=38.4×10 4 g / mol, molecular weight distribution (PDI) 2.91. Low molecular weight part Mw=6.65×10 4 g / mol, Mn=4.07×10 4 g / mol, molecular weight distribution (PDI) 1.63.

[0102] The experimental results of Example 22 showed that the yield of the polymerization product was 88%. It showed a bimodal structure, with the high molecular weight portion Mw = 122.20 × 10 4 g / mol, Mn=43.33×10 4g / mol, molecular weight distribution (PDI) 2.82. Low molecular weight part Mw=11.80×10 4 g / mol, Mn=7.42×10 4 g / mol, molecular weight distribution (PDI) 1.59.

[0103] The experimental results of Example 23 showed that the yield of the polymerization product was 86%. It showed a bimodal structure, with the high molecular weight portion Mw = 201.80 × 10 4 g / mol, Mn=91.31×10 4 g / mol, molecular weight distribution (PDI) 2.21. Low molecular weight part Mw=13.70×10 4 g / mol, Mn=8.78×10 4 g / mol, molecular weight distribution (PDI) 1.56.

[0104] Examples 24-26

[0105] The difference from Example 4 is that the initiator is changed from benzyl methyl ether to ethyl benzoate (Example 24), ethyl 4-chlorobenzoate (Example 25), and 2-(chloromethyl)naphthalene (Example 26).

[0106] The experimental results of Example 24 showed that the yield of the polymerization product was 50%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 99.32×10 4 g / mol, Mn=27.97×10 4 g / mol, molecular weight distribution (PDI) 3.55.

[0107] The experimental results of Example 25 showed that the yield of the polymerization product was 46%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 83.90×10 4 g / mol, Mn=35.71×10 4 g / mol, molecular weight distribution (PDI) 2.35.

[0108] The experimental results of Example 26 showed that the yield of the polymerization product was 41%. It was a high molecular weight polyisobutylene with a unimodal distribution, and its Mw was 103.90×10 4 g / mol, Mn=39.06×10 4 g / mol, molecular weight distribution (PDI) 2.66.

[0109] Examples 27-30

[0110] The difference from Example 6 is that the initiator is changed from dibenzyl ether to benzyl benzoate (Example 27), ethyl 1-naphthoate (Example 28), tert-butyl benzoate (Example 29), and ethyl 2,6-dimethylbenzoate (Example 30).

[0111] The experimental results of Example 27 showed that the yield of the polymer product was 46%. It showed a bimodal structure, with the high molecular weight portion Mw = 136.90 × 10 4 g / mol, Mn=45.48×10 4 g / mol, molecular weight distribution (PDI) 3.01. Low molecular weight part Mw=12.90×10 4 g / mol, Mn=6.97×10 4 g / mol, molecular weight distribution (PDI) 1.85.

[0112] The experimental results of Example 28 showed that the yield of the polymerization product was 72%. It showed a bimodal structure, with the high molecular weight portion Mw = 154.20 × 10 4 g / mol, Mn=60.47×10 4 g / mol, molecular weight distribution (PDI) 2.55. Low molecular weight part Mw=9.83×10 4 g / mol, Mn=7.39×10 4 g / mol, molecular weight distribution (PDI) 1.33.

[0113] The experimental results of Example 29 showed that the yield of the polymer product was 48%. It showed a bimodal structure, with the high molecular weight portion Mw = 119.21×10 4 g / mol, Mn=38.45×10 4 g / mol, molecular weight distribution (PDI) 3.10. Low molecular weight fraction Mw = 11.76×10 4 g / mol, Mn=6.49×10 4 g / mol, molecular weight distribution (PDI) 1.81.

[0114] The experimental results of Example 30 showed that the yield of the polymerization product was 77%. It showed a bimodal structure, with the high molecular weight portion Mw = 173.29 × 10 4 g / mol, Mn=73.74×10 4 g / mol, molecular weight distribution (PDI) 2.35. Low molecular weight part Mw=14.55×10 4 g / mol, Mn=10.69×10 4 g / mol, molecular weight distribution (PDI) 1.36.

[0115] Comparative Example 1

[0116] The difference between Comparative Example 1 and Example 2 is that the initiator is changed from 2,6-dimethylbenzyl alcohol to 4-methoxybenzyl alcohol, and the experimental results show that no high molecular weight product is produced.

[0117] Comparative Example 2

[0118] The difference between Comparative Example 2 and Example 5 is that the molar ratio of the initiator to the co-initiator is changed to 2, and the experimental results show no high molecular weight product.

[0119] Comparative Example 3

[0120] Comparative Example 3 differs from Example 5 in that the coinitiator is changed to aluminum trichloride first and then diisobutylaluminum chloride to initiate the reaction. The calculated yield is 66%. The polyisobutylene has a unimodal distribution and its Mw is 68.3×10 4 g / mol, Mn=3.39×10 4 g / mol, with a molecular weight distribution (PDI) of 20.1. The unimodal PDI distribution of polyisobutylene is too broad, failing to replicate the bimodal distribution of materials. This material, which has two components of varying molecular weights, has a low molecular weight component that acts as a plasticizer, improving processing fluidity, while the high molecular weight component enhances mechanical properties. Compared to bimodal materials, the lack of a distinct high-molecular-weight reinforcing phase may result in relatively poor mechanical properties, particularly the combined strength and toughness. This may limit its suitability for applications requiring high mechanical properties. Furthermore, processing stability and uniformity are poor.

[0121] Comparative Example 4

[0122] The difference between Comparative Example 4 and Example 5 is that the solvent is changed to dimethyl sulfoxide, and the experimental results show no high molecular weight product.

[0123] Comparative Example 5

[0124] The difference between Comparative Example 5 and Example 5 is that the monomer concentration is changed to 60 wt%, and the calculated yield is 98%. It is a high molecular weight polyisobutylene with a unimodal distribution, and its Mw is 26.8×10 4 g / mol, Mn=1.21×10 4 g / mol, with a molecular weight distribution (PDI) of 22.1; its molecular weight is relatively low, and its molecular weight distribution is broad. Compared with bimodal materials, due to the absence of a clear high-molecular-weight reinforcing phase, its mechanical properties, especially the combined performance of high strength and high toughness, may be relatively inferior, potentially limiting its use in applications requiring high mechanical properties. Furthermore, processing stability and uniformity are poor.

Claims

1. A method for preparing high molecular weight polyisobutylene with bimodal distribution, characterized in that: Using an initiator and a co-initiator as a catalytic system and isobutylene as a monomer, high molecular weight polyisobutylene with a unimodal or bimodal distribution is obtained by polymerization; The co-initiator is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, ethylaluminum dichloride, and dichloroisobutylaluminum; The initiator is selected from one or more of 4-methylbenzyl bromide, 2,4-dimethylbenzyl bromide, 4-tert-butylbenzyl bromide, 2,6-dimethylbenzyl chloride, 2,4,6-trimethylbenzyl chloride, 4-tert-butylbenzyl chloride, 3-methoxybenzyl chloride, triphenylmethane, methyl p-methylbenzoate, methyl 4-tert-butylbenzoate, methyl 4-methoxybenzoate, methyl 4-(dimethylamino)benzoate, ethyl 1-naphthoate, tert-butyl benzoate, ethyl 2,6-dimethylbenzoate, ethyl p-methoxybenzoate, diethyl terephthalate, ethyl 4-dimethylaminobenzoate, and benzyl benzoate; The bimodal distribution of high molecular weight polyisobutylene, the weight average molecular weight range of the high molecular weight part is 112.14×10 4 ~250.40×10 4 g / mol, the molecular weight distribution (PDI) is 1.96~3.11; the weight average molecular weight range of the low molecular weight part is 3.28×10 4 ~16.50×10 4 g / mol, and the molecular weight distribution (PDI) is 1.29~1.

96.

2. The method for preparing a bimodal high molecular weight polyisobutylene according to claim 1, characterized in that: The specific steps include: S1: Prepare ingredients: The polymerization reaction system is an anhydrous and oxygen-free inert gas environment, and the solvent after dehydration and deoxygenation, the monomer after dehydration and deoxygenation, the initiator, and the co-initiator are all stored in an inert environment; S2: Aggregation: An initiator is added to the low-temperature constant-temperature reactor, and the low-temperature constant-temperature reactor is replaced with an anhydrous and oxygen-free inert gas environment. A solvent and a monomer are added, and the temperature of the low-temperature constant-temperature reactor is equilibrated for 20 minutes to obtain a polymerization system. A co-initiator is added to initiate the polymerization reaction. After the polymerization is completed, a terminator is added to terminate the polymerization reaction to obtain a polymer product. S3: Post-processing: After removing unreacted monomers and solvent from the polymerization product, the product is soaked in ethanol and then dried to obtain high molecular weight polyisobutylene with bimodal distribution.

3. The method for preparing a bimodal high molecular weight polyisobutylene according to claim 2, characterized in that: In the above-mentioned S1, the solvent is selected from one or more of n-hexane, tetrahydrofuran, methyl chloride, dichloromethane, toluene, ethyl chloride, vinyl chloride, and propane.

4. The method for preparing a high molecular weight polyisobutylene with bimodal distribution according to claim 2, characterized in that: The inert gas is nitrogen or argon.

5. The method for preparing a bimodal high molecular weight polyisobutylene according to claim 2, wherein: In the polymerization system, the mass concentration of isobutylene monomer is 5wt% to 50wt%; The molar ratio of initiator to co-initiator is: (0.01-1):1; The mass percentage of the co-initiator to the monomer is 0.02 to 10 wt%; The equilibrium temperature of the low-temperature constant-temperature reactor is -60℃~-90℃; The polymerization time is 5 to 60 minutes.

6. The method for preparing a high molecular weight polyisobutylene with bimodal distribution according to claim 2, characterized in that: The coinitiator is added in the following manner: when there is only one coinitiator, it is slowly added dropwise at a rate of 0.5 to 2 mL / min; when there are two or more coinitiators, the two coinitiators are slowly added dropwise in sequence with an interval of 0 to 45 minutes; the addition rate is 0.5 to 2 mL / min.

7. The method for preparing a bimodal high molecular weight polyisobutylene according to claim 2, characterized in that: The terminator is selected from one of water, anhydrous methanol, anhydrous ethanol or an ethanol / water mixed solution containing 1wt% NaOH; in the ethanol / water mixed solution, the volume ratio of ethanol:water is 1:1; the amount of the terminator used accounts for 1-5% of the volume percentage of the polymerization system.

8. The method for preparing high molecular weight polyisobutylene with bimodal distribution according to claim 2, characterized in that: In the above-mentioned S3, the method for removing unreacted monomers and solvent is evaporation under reduced pressure; the ethanol soaking time is more than 12 hours; and the drying process parameters are: pressure -0.1 MPa, 40-50° C. and drying to constant weight.

9. A high molecular weight polyisobutylene having a bimodal distribution, characterized in that: The high molecular weight polyisobutylene having a bimodal distribution is prepared by the preparation method according to any one of claims 1 to 8, with a yield of 50% to 99%, and the weight average molecular weight of the high molecular weight portion is in the range of 112.14×10 4 ~250.40×10 4 g / mol, the molecular weight distribution (PDI) is 1.96~3.11; the weight average molecular weight range of the low molecular weight part is 3.28×10 4 ~16.50×10 4 g / mol, and the molecular weight distribution (PDI) is 1.29~1.96.

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