Single-peak / double-peak distribution high-molecular-weight polyisobutene and preparation method thereof

Abstract

The invention discloses unimodal / bimodal distribution high-molecular-weight polyisobutene and a preparation method thereof, and belongs to the field of preparation of high-molecular-weight compounds. According to the preparation method, the high-molecular-weight polyisobutene with the molecular weight in unimodal / bimodal distribution is prepared through a simple initiator and co-initiator system. Using a simple and easily available initiator and Lewis acid with relatively weak corrosion to equipment as co-initiators, and carrying out simple initiator substituent group adjustment and technological process optimization at a relatively high temperature (-60 DEG C to-90 DEG C) to obtain the high molecular weight polyisobutene with the weight-average molecular weight range of 69.69 * 10 < 4 >-275.8 * 10 < 4 > g / mol and monomodal / bimodal distribution, wherein the high molecular weight polyisobutene has a weight-average molecular weight range of 69.69 * 10 < 4 >-275.8 * 10 < 4 > g / mol.

Description

Technical Field

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

[0002] Polyisobutylene (PIB) is divided into low molecular weight polyisobutylene, medium molecular weight polyisobutylene, and high molecular weight polyisobutylene according to different molecular weights. Generally, polyisobutylene with a number average molecular weight (Mn) greater than 100,000 is defined as high molecular weight PIB. Due to its excellent low vulnerability, airtightness, and thermal stability, it is used in the manufacture of tire inner liners, cable insulation layers, heat-insulating and sound-insulating building materials, etc. The PIB polymerization reaction is a typical cationic polymerization, and the active center is particularly active. Industrially, the preparation of high molecular weight polyisobutylene (HPIB) mainly uses strong Lewis acids such as boron trifluoride or aluminum trichloride as a co-initiating system and reacts at extremely low polymerization temperatures (Tp) to inhibit chain transfer and termination reactions. Because of the high difficulty of the preparation process and high equipment costs, its production and application are subject to considerable limitations. This has also led to the long-term high price of high molecular weight polyisobutylene products and a significant increase in the production costs of downstream products.

[0003] The representative patent CN104136470B uses a Lewis acid complex of BF3, iron halide, AlCl3 or alkyl aluminum 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 type" polymerization process to generally prepare a unimodal high molecular weight polyisobutylene with a molecular weight of 75,000 - 10,000,000 g / mol at -80°C to -190°C.

[0004] High molecular weight rubber can endow materials with better physical and mechanical properties, but a higher molecular weight will result in poor processing performance of the rubber. To improve the processing performance, researchers often introduce low molecular weight peaks or "shoulders" through physical blending or chemical methods to obtain a bimodal distribution product, which acts as a plasticizer and endows the material with good processing performance.

[0005] No patents on high molecular weight polyisobutene with bimodal distribution have been retrieved yet. There are relevant patents on other similar materials with bimodal distribution. Patent CN112011018B first synthesizes a poly(styrene-conjugated diene) block polymer, and then reacts it with silicon tetrachloride coupling and HCl gas to obtain a silicon- and chlorine-containing functionalized four-armed star-shaped branching agent. A bimodal distribution star-shaped branched butyl rubber is synthesized under the action of the star-shaped branching agent, main initiator and co-initiator at -60 to 100 °C. Patent CN107344982B first conducts a polymerization reaction in the first loop reactor zone by connecting two loop reactors in series to obtain the first part of the butyl rubber slurry. Then the first part of the butyl rubber slurry is sent to the second loop reactor zone to continue the polymerization reaction, and finally a butyl rubber with a wide / bimodal molecular weight distribution is obtained. Patent CN112142892B prepares a bimodal distribution polyisoprene by reacting a rare earth catalyst for a period of time and then adding another rare earth catalyst.

[0006] In the polymerization of high molecular weight polyisobutene, the strong Lewis acids boron trifluoride and aluminum trichloride as co-initiators have the problem of corrosion to equipment during use, which will lead to an increase in equipment maintenance costs; the ultra-low temperature reaction will cause a large amount of energy consumption.

[0007] In the aspect of high molecular weight rubber with bimodal distribution, there are deficiencies such as the need to introduce other components, more processes, relatively complex processes and large consumption, and unclear bimodal structure in the preparation of star-shaped branching agents, the method of connecting two loop reactors in series or the method of adding two catalysts at intervals of a certain period of time.

[0008] Based on this, the present invention aims at the current problems of corrosion of equipment by strong Lewis acids and a large amount of energy consumption caused by ultra-low temperature. A relatively less corrosive Lewis acid is used as a co-initiator to improve the corrosion problem of equipment during the reaction and reduce the equipment maintenance cost. High molecular weight polyisobutene is obtained at a relatively high temperature (such as -60 °C to -90 °C). And through an initiation system with relatively simple structure and few components and a simple process flow, a high molecular weight polyisobutene product with unimodal or bimodal distribution can be obtained according to requirements, improving the processing performance of the product and the diversity of products. Summary of the Invention

[0009] The object of the present invention is mainly to address the deficiencies in the existing technologies, such as the corrosiveness of strong Lewis acids to equipment, the large amount of energy consumption caused by ultra-low temperatures, the poor processability of single-peak high molecular weight polyisobutylene, and the large number of components and relatively complex processes when synthesizing high molecular weight products with a bimodal structure at present. A single-peak / bimodal distribution high molecular weight polyisobutylene and its preparation method are provided. By using a simple and easily available initiator system and a Lewis acid with relatively weak corrosiveness to equipment as a co-initiator system, at a relatively high temperature (-60°C to -90°C), through simple adjustment of the initiator substituents and optimization of the process flow, a high molecular weight polyisobutylene with a weight average molecular weight (Mw) of 69.69×10 4 ~275.8×10 4 g / mol with a single / bimodal distribution can be obtained.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows: A preparation method of a single-peak / bimodal distribution high molecular weight polyisobutylene of the present invention uses an initiator and a co-initiator as a catalytic system, and uses isobutylene as a monomer to polymerize to obtain a high molecular weight polyisobutylene with a single-peak or bimodal distribution. More preferably, it is a high molecular weight polyisobutylene with a bimodal distribution.

[0011] The initiator for the single-peak / bimodal distribution high molecular weight polyisobutylene is selected from one or more of the following: benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenylethyl ether, dibenzyl ether, benzyl chloride, benzyl bromide, α,α'-dichlorop-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, 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, triphenylmethyl chloride, methyl p-toluate, 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, benzyl benzoate.

[0012] The co-initiator for the high molecular weight polyisobutylene with unimodal / bimodal distribution described above is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, dichloroethylaluminum, and dichloroisobutylaluminum.

[0013] Preferably, when the initiator is selected from one or more of benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenylethyl ether, benzyl chloride, benzyl bromide, α,α'-dichlorop-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, the obtained high molecular weight polyisobutylene has a unimodal distribution; when the initiator is selected from one or more of 4-methylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-tert-butylbenzyl alcohol, benzyl phenyl ether, dibenzyl ether, 2-(p-tolyl)propan-2-ol, 2-(4-methoxyphenyl)propan-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, 3-methoxybenzyl chloride, triphenylmethyl chloride, methyl p-toluate, 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 obtained high molecular weight polyisobutylene has a bimodal distribution.

[0014] A preparation method for the high molecular weight polyisobutylene with unimodal / bimodal distribution of the present invention more specifically includes the following steps: S1: Preparation of materials: The polymerization reaction system is an anhydrous, anaerobic inert gas environment, and the dehydrated and deoxygenated solvent, dehydrated and deoxygenated monomer, initiator, and co-initiator are all stored in an inert environment. S2: Polymerization: Add the initiator to a low-temperature constant temperature reactor, displace the low-temperature constant temperature reactor into an anhydrous, anaerobic inert gas environment, add the solvent and monomer, and keep the temperature in the low-temperature constant temperature reactor balanced for 20 minutes to obtain a polymerization system. Then add the co-initiator to initiate the reaction for polymerization. After the polymerization is completed, add a terminator to terminate the reaction to obtain a polymerization product. S3: Post-treatment: After removing the unreacted monomer and solvent from the polymerization product, soak it in ethanol and then dry it to obtain the high molecular weight polyisobutylene with unimodal / bimodal distribution.

[0015] In the above-mentioned S1, the solvent is selected from one or more of n-hexane, tetrahydrofuran, methyl chloride, dichloromethane, toluene, chloroethane, vinyl chloride, and propane.

[0016] In the above-mentioned S1, the inert gas is preferably nitrogen or argon.

[0017] In the above-mentioned S2, the inert gas is selected from nitrogen or argon.

[0018] In the polymerization system, the mass concentration of isobutene (IB) monomer is 5 wt% to 50 wt%.

[0019] The molar ratio of the initiator to the co-initiator is: (0.01 - 1):1.

[0020] The mass percentage of the co-initiator in the monomer is 0.02 - 10 wt%.

[0021] The equilibrium temperature of the low-temperature constant-temperature reactor is -60°C to -90°C.

[0022] The polymerization time is 5 - 60 min.

[0023] The addition method of the above-mentioned co-initiator is as follows: when there is one co-initiator, it is slowly added dropwise at an addition rate of 0.5 - 2 mL / min; when there are two or more co-initiators, the two co-initiators are slowly added dropwise in sequence with an interval of 0 - 45 min; the addition rate is 0.5 - 2 mL / min.

[0024] The terminator is selected from one of water, anhydrous methanol, anhydrous ethanol, or an ethanol / water mixed solution containing 1 wt% NaOH; in the ethanol / water mixed solution, by volume ratio, ethanol:water = 1:1; the amount of the terminator accounts for 1 - 5% of the volume of the polymerization system.

[0025] In the above-mentioned S3, the method for removing unreacted monomers and solvents is selected as the vacuum evaporation method.

[0026] In the above-mentioned S3, the ethanol soaking time is 12 h or more.

[0027] In the above-mentioned S3, the process parameters for drying are: drying under a pressure of -0.1 MPa at 40 - 50°C until constant weight.

[0028] A single-peak / double-peak distributed high molecular weight polyisobutene of the present invention is prepared by the above preparation method, and its yield is 50% - 99%. When preparing a single-peak distributed high molecular weight polyisobutene, its weight average molecular weight range is from 69.69×10 4 ~275.8×10 4g / mol, the molecular weight distribution (PDI) is 2.06 - 7.00; when preparing bimodal high molecular weight polyisobutylene, the weight average molecular weight range of its 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 its low molecular weight part is 3.28×10 4 ~16.50×10 4 g / mol, the molecular weight distribution (PDI) is 1.29 - 1.96.

[0029] A unimodal / bimodal high molecular weight polyisobutylene and its preparation method of the present invention have the following beneficial effects: (1) By using a simple and easily available initiating system and a Lewis acid with relatively weak corrosiveness to equipment as a co-initiating system, at a relatively high temperature (-60°C to -90°C), through simple substituent adjustment and process flow optimization, a unimodal high molecular weight polyisobutylene with a weight average molecular weight range of 69.69×10 4 ~275.8×10 4 g / mol and a molecular weight distribution (PDI) of 2.06 - 7.00 or a bimodal high molecular weight polyisobutylene with a weight average molecular weight range of 112.14×10 4 ~250.40×10 4 g / mol, a molecular weight distribution (PDI) of 1.96 - 3.11; and a weight average molecular weight range of 3.28×10 4 ~16.50×10 4 g / mol and a molecular weight distribution (PDI) of 1.29 - 1.96 can be obtained.

[0030] (2) The synthesis of high molecular weight polyisobutylene requires the interaction between an initiator and a co-initiator to form a controllable ion pair to achieve controlled polymerization. And by inhibiting / controlling the occurrence of chain transfer to regulate the unimodal / bimodal distribution of the product. And a bimodal structure that can ensure the material properties while improving the processability is obtained by controlling and changing the structure of the initiator in this simple way.

[0031] (3) The process flow described in the present invention is simple, which can shorten the reaction cycle; the conditions are mild, which can effectively save raw material costs and reduce energy consumption; it can control the bimodal structure of the product and effectively improve the product performance. Description of the Drawings

[0032] Figure 1 GPC test curve graphs of the high molecular weight polyisobutylene prepared in Examples 1 - 3.

[0033] Figure 2GPC test curve of high molecular weight polyisobutylene prepared in Examples 4-7. Detailed implementation manners

[0034] The following further illustrates the detailed implementation manners of the present invention in combination with the attached drawings and technical solutions.

[0035] The preparation methods of unimodal / bimodal distributed high molecular weight polyisobutylene in the following examples are as follows: Pre-treatment before experiment: All polymerization reactions are carried out under a nitrogen or argon atmosphere. A double-tube is used to ensure an inert environment for the reaction system. The solvent and isobutene (IB) monomer are dehydrated and deoxygenated under certain conditions, and are stored in an inert environment together with the initiator and co-initiator, strictly ensuring that the system is anhydrous and anoxic.

[0036] The solvents used are one or a mixture of more of n-hexane, tetrahydrofuran, methyl chloride, dichloromethane, toluene, chloroethane, vinyl chloride, and propane.

[0037] General procedure for polymerization reaction: First, add a certain amount of initiator to a Schlenk reaction tube, connect the double-tube, replace the gas three times, and then place it in a low-temperature constant-temperature reactor. Under the condition of ensuring a sufficient flow rate of inert gas, use a syringe with a long needle or a raw material kettle that has been replaced with inert gas three times to sequentially add the solvent and monomer into the reaction tube, and then equilibrate the temperature for 20 min. Add one or two co-initiators to initiate the reaction in a certain addition manner. After reaching the set polymerization time, add a terminator to terminate the reaction.

[0038] The inert environment is nitrogen or argon.

[0039] The concentration of the isobutene (IB) monomer is: 5 wt% - 50 wt%.

[0040] The molar ratio of the initiator to the co-initiator is: (0.01 - 1):1.

[0041] The mass percentage of the co-initiator in the monomer is: 0.02 - 10 wt%.

[0042] The polymerization time is: 5 - 60 min.

[0043] The addition manner of the co-initiator is: One co-initiator is directly added dropwise slowly, and two co-initiators are added dropwise at intervals of 0 - 45 min in sequence.

[0044] The set temperature of the low-temperature constant-temperature reactor is: -60°C to -90°C.

[0045] The terminator is one of the following: water, absolute methanol, absolute ethanol, or an ethanol / water (V / V = 1) mixed solution containing 1 wt% NaOH. The amount of the terminator is generally 1-5% (V / V) of the polymerization system.

[0046] General procedure for post-treatment: After removing unreacted monomers and solvents from the polymerization product by vacuum evaporation, the product is washed and soaked with ethanol for 12 h. Then, the product is dried to a constant weight at a pressure of -0.1 MPa and a temperature of 40 °C, and the yield is calculated. The molecular weight and distribution are measured by gel permeation chromatography (GPC).

[0047] The calculation method for the yield in the examples of the present invention is as follows: The yield is calculated by the weighing method. Yield (%) = mass of PIB polymer (g) / mass of IB monomer (g).

[0048] The molecular weight in the examples of the present invention is measured by the GPC method: The GPC calibrant is polystyrene (PS), and the solvent is tetrahydrofuran (THF). The polymer sample is prepared into a solution with a concentration of 1 mg / mL. Measurements are carried out at a flow rate of 1 mL / min and a column temperature of 35 °C to obtain the average molecular weight and molecular weight distribution data. Among them, the molecular weight distribution (PDI) = weight-average molecular weight (Mw) of the polymerization product / number-average molecular weight (Mn) of the polymerization product.

[0049] Example 1 Set the reaction temperature to -90 °C. Under nitrogen protection, benzyl alcohol as the initiator with a molar mass ratio of 0.05 to the co-initiator and a 30 wt% isobutene (IB) chloromethane solution are successively transferred to a Schlenk tube. After equilibration at the temperature for 20 min, a co-initiator, diisobutylaluminum chloride, with a mass ratio of 0.5 wt% to the monomer is added to initiate the reaction. After reaching the set polymerization time of 30 min, 2 mL of absolute ethanol terminator is added to terminate the reaction. The polymerization product is obtained, and after removing unreacted monomers and solvents, it is dried. The calculated yield is 99%; tested by GPC, the curve is shown in Figure 1 , which is a high-molecular-weight polyisobutene with a single-peak distribution. Mw = 69.69×10 4 g / mol, Mn = 15.84×10 4 g / mol, and the molecular weight distribution (PDI) is 4.39.

[0050] Example 2 Set the reaction temperature at -90 °C. Under nitrogen protection, transfer the initiator 2,6-dimethylbenzyl alcohol with a molar mass ratio of 0.05 to the co-initiator and a 30 wt% isobutene (IB) methyl chloride solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiator diisobutylaluminum chloride with a mass ratio of 0.5 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. The polymerization product is obtained. After removing the unreacted monomers and solvents, it is dried, and the yield is calculated to be 87%. Tested by GPC, the curve graph is shown in Figure 1 , which shows a bimodal structure. The high molecular weight part has Mw = 126.00×10 4 g / mol and Mn = 40.46×10 4 g / mol, and the molecular weight distribution (PDI) is 3.11. The low molecular weight part has Mw = 3.28×10 4 g / mol and Mn = 2.53×10 4 g / mol, and the molecular weight distribution (PDI) is 1.29.

[0051] Example 3 Set the reaction temperature at -90 °C. Under nitrogen protection, transfer the initiator 4-tert-butylbenzyl bromide with a molar mass ratio of 0.05 to the co-initiator and a 30 wt% isobutene (IB) methyl chloride solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiator diisobutylaluminum chloride with a mass ratio of 0.5 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. The polymerization product is obtained. After removing the unreacted monomers and solvents, it is dried, and the yield is calculated to be 93%. Tested by GPC, the curve graph is shown in Figure 1 , which shows a bimodal structure. The high molecular weight part has Mw = 112.14×10 4 g / mol and Mn = 39.01×10 4 g / mol, and the molecular weight distribution (PDI) is 2.87. The low molecular weight part has Mw = 3.30×10 4 g / mol and Mn = 2.50×10 4 g / mol, and the molecular weight distribution (PDI) is 1.33.

[0052] Example 4 Set the reaction temperature to -90 °C. Under nitrogen protection, transfer the initiator benzyl methyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30 wt% isobutene (IB) methyl chloride solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. Obtain the polymerization product. After removing the unreacted monomers and solvents, dry it and calculate the yield to be 55%. Test it by GPC, and the curve graph is shown in Figure 2 , which is a high-molecular-weight polyisobutene with a single-peak distribution, and its Mw = 126.50×10 4 g / mol, Mn = 18.10×10 4 g / mol, and the molecular weight distribution (PDI) is 7.00.

[0053] Example 5 Set the reaction temperature to -90 °C. Under nitrogen protection, transfer the initiator benzyl ethyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30 wt% isobutene (IB) methyl chloride solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. Obtain the polymerization product. After removing the unreacted monomers and solvents, dry it and calculate the yield to be 50%. After testing by GPC, the curve graph is shown in Figure 2 , which is a high-molecular-weight polyisobutene with a single-peak distribution, and its Mw = 140.10×10 4 g / mol, Mn = 45.40×10 4 g / mol, and the molecular weight distribution (PDI) is 3.07.

[0054] Example 6 Set the reaction temperature to -90 °C. Under nitrogen protection, transfer the initiator dibenzyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30 wt% isobutene (IB) methyl chloride solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. Obtain the polymerization product. After removing the unreacted monomers and solvents, dry it and calculate the yield to be 66%. After testing by GPC, the curve graph is shown in Figure 2 , which has a bimodal structure. The high-molecular-weight part has Mw = 199.20×10 4 g / mol, Mn = 92.60×10 4g / mol, the molecular weight distribution (PDI) is 2.15. The low molecular weight part Mw = 10.80×10 4 g / mol, Mn = 6.70×10 4 g / mol, the molecular weight distribution (PDI) is 1.59.

[0055] Example 7 Set the reaction temperature to -90 °C. Under nitrogen protection, transfer the initiator benzyl phenyl ether with a molar mass ratio of 0.1 to the co-initiator and a 30 wt% isobutene (IB) monochloromethane solution to a Schlenk tube in sequence. After equilibrating the temperature for 20 min, add the co-initiators diisobutylaluminum chloride and dimethylaluminum chloride with a mass ratio of 0.8 wt% to the monomer to initiate the reaction. After reaching the set polymerization time of 30 min, add 2 mL of anhydrous ethanol terminator to terminate the reaction. Obtain the polymerization product. After removing the unreacted monomers and solvents, dry it and calculate the yield to be 52%. After GPC testing, its curve is shown in Figure 2 , which shows a bimodal structure. The high molecular weight part Mw = 250.40×10 4 g / mol, Mn = 128.00×10 4 g / mol, the molecular weight distribution (PDI) is 1.96; the low molecular weight part Mw = 16.50×10 4 g / mol, Mn = 8.40×10 4 g / mol, the molecular weight distribution (PDI) is 1.96.

[0056] Example 8 The difference between Example 8 and Example 5 is that the reaction temperature in Example 5 is changed from -90 °C to -75 °C.

[0057] The experimental result of Example 8 is that the yield of the polymerization product is 85%. After GPC testing, it is a high molecular weight polyisobutene with a unimodal distribution, and its Mw = 122.50×10 4 g / mol, Mn = 19.10×10 4 g / mol, the molecular weight distribution (PDI) is 6.41.

[0058] Example 9 The difference between Example 9 and Example 5 is that the reaction temperature in Example 5 is changed from -90 °C to -60 °C.

[0059] The experimental result of Example 9 is that the yield of the polymerization product is 74%. After GPC testing, it is a high molecular weight polyisobutene with a unimodal distribution, and its Mw = 73.80×10 4 g / mol, Mn = 33.90×10 4 g / mol, the molecular weight distribution (PDI) is 2.17.

[0060] Example 10 Example 10 is different from Example 5 in that the monochloromethane used in Example 5 is changed to n-hexane as the solvent; The experimental result of Example 10 is that the yield of the polymerization product is 67%. After GPC test, it is a high molecular weight polyisobutylene with a single peak distribution, and its Mw = 153.5×10 4 g / mol, Mn = 74.40×10 4 g / mol, and the molecular weight distribution (PDI) is 2.06.

[0061] Example 11 Example 11 is different from Example 5 in that the polymerization time of Example 5 is changed from 30 min to 60 min; The experimental result of Example 11 is that the yield of the polymerization product is 100%. After GPC test, it is a high molecular weight polyisobutylene with a single peak distribution, and its Mw = 161.10×10 4 g / mol, Mn = 51.63×10 4 g / mol, and the molecular weight distribution (PDI) is 3.12.

[0062] Example 12 Example 12 is different from Example 5 in that the addition of diisobutylaluminum chloride and dimethylaluminum chloride to initiate the reaction in Example 5 is changed to adding dimethylaluminum chloride to initiate the reaction 30 min after adding diisobutylaluminum chloride.

[0063] The experimental result of Example 12 is that the yield of the polymerization product is 65%. After GPC test, it is a high molecular weight polyisobutylene with a single peak distribution, and its Mw = 275.80×10 4 g / mol, Mn = 112.3×10 4 g / mol, and the molecular weight distribution (PDI) is 2.45.

[0064] Examples 13 - 16 Examples 13 - 16 are different from Example 1 in 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).

[0065] The experimental result of Example 13 is that the yield of the polymerization product is 77%. It is a high molecular weight polyisobutylene with a single peak distribution, and its Mw = 72.51×10 4 g / mol, Mn = 26.70×10 4 g / mol, and the molecular weight distribution (PDI) is 2.71.

[0066] The experimental result of Example 14 is that the yield of the polymerization product is 83%. It is a high-molecular-weight polyisobutene with a unimodal distribution, and its Mw = 81.30×10 4 g / mol, Mn = 27.01×10 4 g / mol, and the molecular weight distribution (PDI) is 3.01.

[0067] The experimental result of Example 15 is that the yield of the polymerization product is 66%. It is a high-molecular-weight polyisobutene with a unimodal distribution, and its Mw = 73.90×10 4 g / mol, Mn = 14.50×10 4 g / mol, and the molecular weight distribution (PDI) is 5.10.

[0068] The experimental result of Example 16 is that the yield of the polymerization product is 52%. It is a high-molecular-weight polyisobutene with a unimodal distribution, and its Mw = 79.21×10 4 g / mol, Mn = 13.60×10 4 g / mol, and the molecular weight distribution (PDI) is 5.83.

[0069] Examples 17 - 19 The difference from Example 2 lies in 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).

[0070] The experimental result of Example 17 is that the yield of the polymerization product is 90%. It has a bimodal structure. The high-molecular-weight part has Mw = 112.30×10 4 g / mol, Mn = 48.80×10 4 g / mol, and the molecular weight distribution (PDI) is 2.30. The low-molecular-weight part has Mw = 11.91×10 4 g / mol, Mn = 7.32×10 4 g / mol, and the molecular weight distribution (PDI) is 1.62.

[0071] The experimental result of Example 18 is that the yield of the polymerization product is 55%. It has a bimodal structure. The high-molecular-weight part has Mw = 123.55×10 4 g / mol, Mn = 54.82×10 4 g / mol, and the molecular weight distribution (PDI) is 2.25. The low-molecular-weight part has Mw = 12.30×10 4 g / mol, Mn = 8.10×10 4 g / mol, and the molecular weight distribution (PDI) is 1.52.

[0072] The experimental result of Example 19 is that the yield of the polymerization product is 73%. It has a bimodal structure. The high molecular weight part has Mw = 155.80×10 4 g / mol, Mn = 53.71×10 4 g / mol, and the molecular weight distribution (PDI) is 2.90. The low molecular weight part has Mw = 9.8×10 4 g / mol, Mn = 6.9×10 4 g / mol, and the molecular weight distribution (PDI) is 1.42.

[0073] Examples 20 - 23 The difference from Example 3 lies in 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), triphenylmethyl chloride (Example 23).

[0074] The experimental result of Example 20 is that the yield of the polymerization product is 88%. It has a bimodal structure. The high molecular weight part has Mw = 126.20×10 4 g / mol, Mn = 58.46×10 4 g / mol, and the molecular weight distribution (PDI) is 2.30. The low molecular weight part has Mw = 6.92×10 4 g / mol, Mn = 5.20×10 4 g / mol, and the molecular weight distribution (PDI) is 1.33.

[0075] The experimental result of Example 21 is that the yield of the polymerization product is 91%. It has a bimodal structure. The high molecular weight part has Mw = 113.28×10 4 g / mol, Mn = 38.4×10 4 g / mol, and the molecular weight distribution (PDI) is 2.91. The low molecular weight part has Mw = 6.65×10 4 g / mol, Mn = 4.07×10 4 g / mol, and the molecular weight distribution (PDI) is 1.63.

[0076] The experimental result of Example 22 is that the yield of the polymerization product is 88%. It has a bimodal structure. The high molecular weight part has Mw = 122.20×10 4 g / mol, Mn = 43.33×10 4 g / mol, and the molecular weight distribution (PDI) is 2.82. The low molecular weight part has Mw = 11.80×10 4 g / mol, Mn = 7.42×10 4 g / mol, and the molecular weight distribution (PDI) is 1.59.

[0077] The experimental result of Example 23 is that the yield of the polymerization product is 86%. It has a bimodal structure. The high molecular weight part has Mw = 201.80×10 4 g / mol, Mn = 91.31×10 4 g / mol, and the molecular weight distribution (PDI) is 2.21. The low molecular weight part has Mw = 13.70×10 4 g / mol, Mn = 8.78×10 4 g / mol, and the molecular weight distribution (PDI) is 1.56.

[0078] Examples 24 - 26 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), 2-(chloromethyl)naphthalene (Example 26).

[0079] The experimental result of Example 24 is that the yield of the polymerization product is 50%. It is a high molecular weight polyisobutene with a unimodal distribution, and its Mw = 99.32×10 4 g / mol, Mn = 27.97×10 4 g / mol, and the molecular weight distribution (PDI) is 3.55.

[0080] The experimental result of Example 25 is that the yield of the polymerization product is 46%. It is a high molecular weight polyisobutene with a unimodal distribution, and its Mw = 83.90×10 4 g / mol, Mn = 35.71×10 4 g / mol, and the molecular weight distribution (PDI) is 2.35.

[0081] The experimental result of Example 26 is that the yield of the polymerization product is 41%. It is a high molecular weight polyisobutene with a unimodal distribution, and its Mw = 103.90×10 4 g / mol, Mn = 39.06×10 4 g / mol, and the molecular weight distribution (PDI) is 2.66.

[0082] Examples 27 - 30 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), ethyl 2,6-dimethylbenzoate (Example 30).

[0083] The experimental result of Example 27 is that the yield of the polymerization product is 46%. It has a bimodal structure. The high molecular weight part has Mw = 136.90×10 4 g / mol, Mn = 45.48×10 4 g / mol, and the molecular weight distribution (PDI) is 3.01. The low molecular weight part has Mw = 12.90×104 g / mol, Mn = 6.97×10 4 g / mol, polydispersity index (PDI) 1.85.

[0084] The experimental result of Example 28 is that the yield of the polymerization product is 72%. It has a bimodal structure. The high molecular weight part has Mw = 154.20×10 4 g / mol, Mn = 60.47×10 4 g / mol, polydispersity index (PDI) 2.55. The low molecular weight part has Mw = 9.83×10 4 g / mol, Mn = 7.39×10 4 g / mol, polydispersity index (PDI) 1.33.

[0085] The experimental result of Example 29 is that the yield of the polymerization product is 48%. It has a bimodal structure. The high molecular weight part has Mw = 119.21×10 4 g / mol, Mn = 38.45×10 4 g / mol, polydispersity index (PDI) 3.10. The low molecular weight part has Mw = 11.76×10 4 g / mol, Mn = 6.49×10 4 g / mol, polydispersity index (PDI) 1.81.

[0086] The experimental result of Example 30 is that the yield of the polymerization product is 77%. It has a bimodal structure. The high molecular weight part has Mw = 173.29×10 4 g / mol, Mn = 73.74×10 4 g / mol, polydispersity index (PDI) 2.35. The low molecular weight part has Mw = 14.55×10 4 g / mol, Mn = 10.69×10 4 g / mol, polydispersity index (PDI) 1.36.

[0087] Comparative Example 1 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 result shows no high molecular weight product.

[0088] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that the molar ratio of the amounts of the initiator and the co-initiator is changed to 2, and the experimental result shows no high molecular weight product.

[0089] Comparative Example 3 The difference between Comparative Example 3 and Example 5 is that the co-initiator is changed to add aluminum trichloride as the co-initiator first and then add diisobutylaluminum chloride to initiate the reaction, and the calculated yield is 66%. It is polyisobutylene with a unimodal distribution, where Mw = 68.3×10 4 g / mol, Mn = 3.39×10 4 g / mol, and the molecular weight distribution (PDI) is 20.1. The PDI distribution of the unimodal polyisobutylene is too wide. Since the bimodal distribution material has two components with different molecular weights, the low molecular weight part can act as a plasticizer to improve the processing fluidity of the material; the high molecular weight part can enhance the mechanical properties of the material. Compared with the bimodal distribution material, due to the absence of a clear high molecular weight reinforcing phase, its mechanical properties, especially the comprehensive performance of high strength and high toughness, may be relatively poor and may be limited in application scenarios with high requirements for the mechanical properties of the material; at the same time, the processing stability and uniformity are not good.

[0090] Comparative Example 4 The difference between Comparative Example 4 and Example 5 is that the solvent is changed to dimethyl sulfoxide, and there is no high molecular weight product in the experimental results.

[0091] Comparative Example 5 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 high molecular weight polyisobutylene with a unimodal distribution, where Mw = 26.8×10 4 g / mol, Mn = 1.21×10 4 g / mol, and the molecular weight distribution (PDI) is 22.1; its molecular weight is relatively low and the molecular weight distribution is wide. Compared with the bimodal distribution material, due to the absence of a clear high molecular weight reinforcing phase, its mechanical properties, especially the comprehensive performance of high strength and high toughness, may be relatively poor and may be limited in application scenarios with high requirements for the mechanical properties of the material; at the same time, the processing stability and uniformity are not good.

Claims

1. A method for preparing a high molecular weight polyisobutylene with a unimodal / bimodal distribution, characterized in that, Using an initiator and a co-initiator as a catalytic system, and using isobutene as a monomer, a high molecular weight polyisobutene with a single-peak or bimodal distribution is polymerized; The initiator is selected from one or more of benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenylethyl ether, dibenzyl ether, benzyl chloride, benzyl bromide, α,α'-dichlorop-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, 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, triphenylmethyl chloride, 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, benzyl benzoate; The co-initiator is selected from one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, dichloroethylaluminum, dichloroisobutylaluminum.

2. The preparation method of the high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 1, characterized in that, When the initiator is selected from one or more of benzyl alcohol, 2-phenyl-2-propanol, benzyl methyl ether, benzyl ethyl ether, phenylethyl ether, benzyl chloride, benzyl bromide, α,α'-dichlorop-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, the resulting high molecular weight polyisobutene has a unimodal distribution; when the initiator is selected from one or more of 4-methylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-tert-butylbenzyl alcohol, benzyl phenyl ether, dibenzyl ether, 2-(p-tolyl)propan-2-ol, 2-(4-methoxyphenyl)propan-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, 3-methoxybenzyl chloride, triphenylmethyl chloride, methyl p-toluate, 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, benzyl benzoate, the resulting high molecular weight polyisobutene has a bimodal distribution.

3. The preparation method of the high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 1, characterized in that, Specifically, it includes the following steps: S1: Preparation of materials: The polymerization reaction system is an anhydrous, oxygen-free inert gas environment. The solvent, monomer, initiator, and co-initiator after water and oxygen removal are all stored in an inert environment. S2: Polymerization: Add the initiator to the low-temperature constant-temperature reactor, displace the low-temperature constant-temperature reactor into an anhydrous, oxygen-free inert gas environment, add the solvent and monomer, and keep it at the equilibrium temperature of the low-temperature constant-temperature reactor for 20 min to obtain a polymerization system. Add the co-initiator to initiate the reaction for polymerization. After the polymerization is completed, add a terminator to terminate the reaction to obtain a polymerization product. S3: Post-treatment: After removing the unreacted monomer and solvent from the polymerization product, soak it in ethanol and dry it to obtain high molecular weight polyisobutene with a unimodal / bimodal distribution.

4. The method for preparing high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 3, characterized in that, In the above S1, the solvent is selected from one or more of n-hexane, tetrahydrofuran, chloromethane, dichloromethane, toluene, chloroethane, vinyl chloride, propane.

5. The preparation method of the high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 3, characterized in that, The inert gas is nitrogen or argon.

6. The method for preparing the high molecular weight polyisobutylene with a unimodal / bimodal distribution according to claim 3, wherein In the polymerization system, the mass concentration of isobutene monomer is 5 wt% - 50 wt%. The molar ratio of the initiator to the co-initiator is (0.01 - 1):

1. The mass percentage of the co-initiator in the monomer is 0.02 - 10 wt%. The equilibrium temperature of the low-temperature constant-temperature reactor is -60 °C to -90 °C. The polymerization time is 5 - 60 min.

7. The method for preparing a high molecular weight polyisobutylene having a unimodal / bimodal distribution according to claim 3, characterized in that, The addition method of the co-initiator is as follows: when there is one co-initiator, it is slowly added dropwise at a rate of 0.5 - 2 mL / min; when there are two or more co-initiators, the two co-initiators are added dropwise slowly at intervals of 0 - 45 min in sequence; the addition rate is 0.5 - 2 mL / min.

8. The method for preparing the high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 3, characterized in that, The terminator is selected from one of water, anhydrous methanol, anhydrous ethanol or an ethanol / water mixed solution containing 1 wt% NaOH; in the ethanol / water mixed solution, by volume ratio, ethanol:water = 1:1; the dosage of the terminator accounts for 1-5% of the volume of the polymerization system.

9. The preparation method of the high molecular weight polyisobutylene with unimodal / bimodal distribution according to claim 3, characterized in that, In the S3 described above, the method for removing unreacted monomers and solvents is selected as the vacuum evaporation method; the ethanol soaking time is 12 h or more; the process parameters for drying are: pressure -0.1 MPa, drying at 40-50 °C to constant weight.

10. A high molecular weight polyisobutylene with a unimodal / bimodal distribution, characterized in that, Prepared by the preparation method according to any one of claims 1-9, with a yield of 50% to 99%. When preparing a single-peak distributed high molecular weight polyisobutene, its weight average molecular weight range is from 69.69×10 4 to 275.8×10 4 g / mol, and the molecular weight distribution (PDI) is 2.06 to 7.00; when preparing a bimodal distributed high molecular weight polyisobutene, the weight average molecular weight range of its high molecular weight part is 112.14×10 4 to 250.40×10 4 g / mol, and the molecular weight distribution (PDI) is 1.96 to 3.11; the weight average molecular weight range of its low molecular weight part is 3.28×10 4 to 16.50×10 4 g / mol, and the molecular weight distribution (PDI) is 1.29 to 1.96.

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