Ethylene-butadiene polymers, process for their preparation and vulcanizates

Abstract

This invention relates to the field of synthetic rubber, and discloses an ethylene-butadiene polymer, its preparation method, and a vulcanized rubber. The ethylene-butadiene polymer comprises polyethylene segments and cis-butadiene rubber segments; based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segments is 0.1-40 wt%, and the content of the cis-butadiene rubber segments is 60-99.9 wt%; among the cis-butadiene rubber segments, based on the total amount of the cis-butadiene rubber segments, the content of cis-1,4-structure is 90-98.5 mol%; based on the total weight of the ethylene-butadiene polymer, the content of toluene-insoluble matter is 0.3-9 wt%. This ethylene-butadiene polymer introduces ethylene structural segments into the butadiene structural segments of the cis-butadiene rubber, thereby modifying the cis-butadiene rubber and giving the ethylene-butadiene polymer improved tensile strength and tear resistance.

Description

Technical Field

[0001] This invention relates to the field of synthetic rubber, specifically to an ethylene-butadiene polymer, its preparation method, and vulcanized rubber. Background Technology

[0002] Butadiene rubber (BR) is a type of rubber material simply synthesized from inexpensive butadiene monomers. BR molecules have regular chains and no other substituent groups. Due to the presence of C-C single bonds and a large number of free chains, the molecules are very soft. Its unique resilience, excellent wear resistance, cold resistance, and dynamic properties have established its irreplaceable position in many fields such as tires, footwear, damping and shock absorption, and sealing. However, BR also has shortcomings such as low tensile strength, tear strength, and flexural strength, poor wet slip resistance, susceptibility to cold flow, and poor aging resistance, which limit its application range. Therefore, it is necessary to reinforce and modify BR to overcome its inherent shortcomings and expand its application scope.

[0003] US4340685A discloses a cobalt-carbon disulfide catalyst system for the in-situ synthesis of blends of cis-1,4-polybutadiene / meta-isotrigonal 1,2-polybutadiene, and the production of VCR rubber. The acidic gases generated by the use of carbon disulfide are highly corrosive to production equipment, and their residue in the rubber has a certain impact on its performance.

[0004] CN105814132A discloses a method for synthesizing polybutadiene composite materials by in-situ blending cis-1,4-polybutadiene with meta-isopropyl-1,2-polybutadiene. This in-situ copolymerization method requires two catalytic systems during the polymerization process. First, a lanthanide catalyst is used to polymerize cis-1,4-polybutadiene. Then, a cobalt-based catalyst with added carbon disulfide is used to polymerize the cis-1,4-polybutadiene mixture to form meta-isopropyl-1,2-polybutadiene, thereby producing composite polybutadiene.

[0005] US9985115B2, US6291591B2, and US6331594B2 disclose the synthesis of cis-1,4-polybutadiene / meta-isopropyl-1,2-polybutadiene blends by polymerizing butadiene in cis-butadiene-saturated alkanes using iron, chromium, or molybdenum catalysts. However, this in-situ generation of meta-isopropyl-1,2-polybutadiene in combination with cis-butadiene solutions suffers from insufficient polymerization activity due to the cis-butadiene as the dispersed phase. The polymerization process is difficult to control, and the composition is not easily adjusted. More importantly, the two materials have poor compatibility, easily leading to phase separation and interface problems, thus affecting material properties.

[0006] Currently, improving the tensile strength and tear resistance of butadiene rubber products, thereby enhancing their performance and service life, requires the development of new butadiene rubber reinforcement technologies. Summary of the Invention

[0007] The purpose of this invention is to improve the shortcomings of existing butadiene rubber materials in terms of tensile strength and tear resistance, and to provide an ethylene-butadiene polymer, its preparation method, and vulcanized rubber. This ethylene-butadiene polymer introduces ethylene structural segments into the butadiene structural segments of the butadiene rubber, thereby modifying the butadiene rubber. Furthermore, the ethylene-butadiene polymer contains a specific amount of toluene-insoluble matter, resulting in improved tensile strength and tear resistance.

[0008] To achieve the above objectives, a first aspect of the present invention provides an ethylene-butadiene polymer comprising polyethylene segments and cis-butadiene rubber segments; based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segments is 0.1-40 wt%, and the content of the cis-butadiene rubber segments is 60-99.9 wt%; of the cis-butadiene rubber segments, based on the total amount of the cis-butadiene rubber segments, the content of cis-1,4-structure is 90-98.5 mol%; and based on the total weight of the ethylene-butadiene polymer, the content of toluene-insoluble matter is 0.2-10 wt%.

[0009] A second aspect of the present invention provides a method for preparing an ethylene-butadiene polymer, the method comprising the following steps:

[0010] (1) In the presence of organic solvent and catalyst, butadiene monomer is polymerized by aluminum-containing co-catalyst-1 to obtain polybutadiene product;

[0011] (2) Add aluminum-containing co-catalyst-2 to the polymerization system obtained in step (1), and then introduce ethylene monomer and polybutadiene active chain segment in the polybutadiene product to carry out copolymerization reaction to obtain the ethylene-butadiene polymer.

[0012] A third aspect of the present invention provides an ethylene-butadiene polymer prepared by the preparation method of the present invention.

[0013] A fourth aspect of the present invention provides a vulcanized rubber made from a composition comprising the ethylene-butadiene polymer of the present invention.

[0014] Through the above technical solutions, the ethylene-butadiene polymer, its preparation method, and the vulcanized rubber provided by the present invention achieve the following beneficial effects:

[0015] The ethylene-butadiene polymer provided by this invention comprises polyethylene segments and cis-butadiene rubber segments. By introducing ethylene structural segments into the butadiene structural segments of cis-butadiene rubber, the cis-butadiene rubber is modified. This chemical linking method effectively avoids the problems of phase separation and interface failure caused by direct blending of polyethylene and cis-butadiene rubber in traditional processes. Furthermore, the polymer contains a specific amount of toluene-insoluble matter, which results in vulcanized rubber made from the composition containing this ethylene-butadiene polymer having improved tensile strength and tear resistance.

[0016] The method for preparing ethylene-butadiene polymer provided by this invention employs a one-step polymerization process in the presence of a catalyst to simultaneously synthesize two traditional polymers, polyethylene and cis-butadiene rubber. Furthermore, the in-situ polymerization yields the ethylene-butadiene polymer containing polyethylene segments and cis-butadiene rubber as described in this invention. Compared to stepwise polymerization, the preparation method provided by this invention offers advantages such as simple process, high operability, low cost, and easier adjustment of the polymerization process and composite material composition, which are beneficial for industrial production. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides an ethylene-butadiene polymer, characterized in that the ethylene-butadiene polymer comprises polyethylene segments and cis-butadiene rubber segments; based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segments is 0.1-40 wt%, and the content of the cis-butadiene rubber segments is 60-99.9 wt%; in the cis-butadiene rubber segments, based on the total molar amount of the cis-butadiene rubber segments, the content of the cis-1,4-structure is 90-98.5 mol%.

[0019] Based on the total weight of the ethylene-butadiene polymer, the content of toluene-insoluble matter is 0.2-10 wt%.

[0020] In this invention, the ethylene-butadiene polymer comprises polyethylene segments and cis-butadiene rubber segments. By introducing ethylene segments into the butadiene structural segments of the cis-butadiene rubber, the cis-butadiene rubber is modified, resulting in excellent compatibility between the reinforcing polyethylene phase and the matrix cis-butadiene rubber. This avoids problems such as phase separation and interface failure caused by direct blending of polyethylene and cis-butadiene rubber in traditional processes. Furthermore, the polymer contains a specific amount of toluene-insoluble matter, which can reinforce the vulcanized rubber and give the vulcanized rubber made from the composition containing the ethylene-butadiene polymer improved tensile strength and tear resistance.

[0021] Furthermore, when the content of polyethylene segments in the ethylene-butadiene polymer, the content of cis-butadiene segments, and the content of cis-1,4-structures in the cis-butadiene rubber meet the above-mentioned ranges, the tensile strength and tear strength of the vulcanized rubber made from the composition containing the ethylene-butadiene polymer can be further improved.

[0022] In this invention, the toluene-insoluble matter refers to the component in the ethylene-isoprene polymer that is insoluble in toluene when tested according to SH / T 1050-2014.

[0023] In this invention, the content of toluene-insoluble matter in the ethylene-isoprene polymer was measured with reference to SH / T1050-2014.

[0024] In some preferred embodiments of the present invention, preferably, based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segment is 1-35 wt%, and the content of the cis-butadiene segment is 65-99 wt%.

[0025] In some preferred embodiments of the present invention, preferably, the content of cis-1,4-structure in the cis-butadiene rubber segments is 92-98 mol% based on the total molar amount of the cis-butadiene rubber segments.

[0026] In some preferred embodiments of the present invention, preferably, the content of toluene-insoluble matter is 0.3-9 wt% based on the total weight of the ethylene-butadiene polymer.

[0027] In this invention, the contents of polyethylene segments and cis-butadiene segments in the ethylene-butadiene polymer, as well as the contents of cis-1,4-structure in the cis-butadiene rubber segments, were determined by 1H NMR spectroscopy.

[0028] In some preferred embodiments of the present invention, the number-average molecular weight of the ethylene-butadiene polymer is preferably 50,000 to 700,000, and more preferably 80,000 to 500,000.

[0029] In some preferred embodiments of the present invention, the molecular weight distribution of the ethylene-butadiene polymer is preferably 2-5, and more preferably 2.5-4.5.

[0030] In this invention, the number-average molecular weight and molecular weight distribution of the ethylene-butadiene polymer were determined by the GPC method.

[0031] In some preferred embodiments of the present invention, the total weight of the toluene-insoluble matter includes a polyethylene segment content of 85-95 wt%.

[0032] In this invention, the content of polyethylene segments in toluene-insoluble matter was determined by 1H NMR spectroscopy.

[0033] In this invention, when the content of polyethylene segments in toluene-insoluble matter meets the above-mentioned range, it is beneficial to achieve effective compatibility between polyethylene segments and isoprene segments in ethylene-butadiene polymers without phase separation, thereby further improving the tensile strength and tear resistance of the obtained vulcanizate.

[0034] A second aspect of the present invention provides a method for preparing ethylene-butadiene polymer, characterized in that the method comprises the following steps:

[0035] (1) In the presence of organic solvent and catalyst, butadiene monomer is polymerized by aluminum-containing co-catalyst-1 to obtain polybutadiene product;

[0036] (2) Add aluminum-containing co-catalyst-2 to the polymerization system obtained in step (1), and then introduce ethylene monomer and polybutadiene active chain segment in the polybutadiene product to carry out copolymerization reaction to obtain the ethylene-butadiene polymer.

[0037] In the method for preparing ethylene-butadiene polymer described in this invention, a one-step polymerization process is used in the presence of a catalyst to simultaneously synthesize two traditional polymers, polyethylene and polybutadiene rubber. The in-situ polymerization yields the ethylene-butadiene polymer containing polyethylene segments and polybutadiene rubber as described in this invention. In this polybutadiene rubber, the polyethylene segments and polybutadiene segments are chemically bonded together, which significantly improves the overall properties of the polybutadiene rubber, especially its tensile properties and tear resistance.

[0038] Meanwhile, compared with stepwise polymerization, the preparation method provided by this invention has the advantages of simple process, strong operability, low cost, and easier adjustment of polymerization process and composite material composition, which is conducive to industrial production.

[0039] Specifically, by using the method provided by the present invention, it is possible to obtain the ethylene-butadiene polymer comprising a specific amount of polyethylene segments and cis-butadiene rubber segments as described in the first aspect of the present invention, wherein the cis-butadiene rubber contains a specific amount of cis-1,4-structure.

[0040] In some embodiments of the present invention, butadiene polymerization can be carried out first, followed by copolymerization of polybutadiene and ethylene monomers. The two reaction processes can be carried out continuously, and the same catalyst can be used in both the polymerization and copolymerization reactions. Different monomers can then be initiated by different co-catalysts to achieve the synthesis of different monomer segments.

[0041] In some embodiments of the present invention, preferably, the catalyst is a cobalt-based catalyst containing cobalt organic compounds.

[0042] In some embodiments of the present invention, preferably, in step (1), the catalyst is selected from at least one of the compounds shown in Formula 1, Formula 2, and Formula 3:

[0043]

[0044]

[0045] Where X is chlorine or bromine;

[0046] R1 is H, or a monosubstituted group at the 2 or 4 position of the benzene ring, or a monosubstituted group at the 2, 4 or 2, 6 position of the benzene ring, or a trisubstituted group at the 2, 4, 6 position of the benzene ring, and the substituent is -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2;

[0047] R3 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with a monosubstituted 6-position on the pyridine ring, or -CH3, -N(CH3)2 or -CF3 with a monosubstituted 4-position on the pyridine ring, or the same or different -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, -N(CH3)2 or -CF3 with double substitutions at the 4 and 6 positions on the pyridine ring;

[0048] R5 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with a monosubstituted 4-position on the dihydrooxazole ring;

[0049] R2, R4, and R6 are each independently hydrogen, or monosubstituted at the 4-position of the pyridine ring with -Cl, -F, -CH3, -OCH3, -N(CH3)2, or -CF3.

[0050] In some embodiments of the present invention, R1 represents a substituent on the benzene ring in Formula 1, allowing all substitution sites on the benzene ring to be H, preferably R1 is H; or R1 represents that some substitution sites on the benzene ring are substituents other than H, as mentioned above, monosubstituted at positions 2 or 4 of the benzene ring, or disubstituted at positions 2 and 4 or 2 and 6 of the benzene ring, or trisubstituted at positions 2, 4, and 6 of the benzene ring, with other substitution sites being H. In the case of disubstituted and trisubstituted, the substituents can be the same or different. Preferably, the monosubstituted at positions 2 or 4 of the benzene ring are -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C 6H5 or -CH(C6H5)2, or -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with disubstituted positions at 2, 4 or 2, 6 on the benzene ring, or -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with trisubstituted positions at 2, 4, 6 on the benzene ring, more specifically, with one of the following groups indicating substitution positions on the benzene ring: 2-F-, 2-CH3-, 4-F-, 4-CH3-, 2,4- F-, 2,4-CH3-, 2,6-F-, 2,6-CH3-, 2,4,6-F-, 2,4,6-CH3-, 2-CH2CH3-, 4-CH2CH3-, 2,4-CH2CH3-, 2-CH2CH3-4-CH3-, 2,6-C H2CH3-, 2-CH2CH3-6-CH3-, 2,4,6-CH2CH3-, 2-CH(CH3)2-, 4-CH(CH3)2-, 2,4-CH(CH3)2-, 2,6-CH(CH3)2-, 2,4,6-CH(CH3) 2-, 2-C(CH3)3-, 4-C(CH3)3-, 2,4-C(CH3)3-, 2,6-C(CH3)3-, 2-C(CH3)3-6-CH3-, 2,4,6-C(CH3)3-, 2-C6H5-, 4-C6H5-, 2,4-C6H5-, 2,6-C6H5-, 2,4,6-C6H5-, 2-CH(C6H5)2-, 4-CH(C6H5)2-, 2,4-CH(C6H5)2-, 2,6-CH(C6H5)2-, 2,4,6-CH(C6H5)2-. In this invention, the number preceding the substituent refers to the substitution position on the benzene ring. For example, 2-F- refers to the -F substitution at the 2-position on the benzene ring.

[0051] In some embodiments of the present invention, R3 represents a substituent on the pyridine ring (different from the pyridine ring substituted by R4) in Formula 2, allowing all substitution positions on the pyridine ring to be H, preferably R3 is H; or R3 represents a substituent group other than H on some substitution positions on the pyridine ring, as mentioned above, a monosubstituted pyridine ring at positions 4 or 6, or a disubstituted pyridine ring at positions 4 and 6, wherein the substitution positions are H. In the case of disubstituted pyridine ring, the substituents can be the same or different. Preferably, the monosubstituted pyridine ring at position 6 is -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5, or -CH(C6H5)2, or the monosubstituted pyridine ring at position 4 is -CH3, -N(CH3)2, or -CF3, or the disubstituted pyridine ring at positions 4 and 6 is -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, or -N(CH3)2. Or -CF3, more specifically, with one of the following groups indicated by a substitution position on the pyridine ring: 6-CH3-, 6-CH2CH3-, 6-C6H5-, 6-CH(C6H5)2-, 4-CH3-, 4-N(CH3)2-, 4-CF3-, 4,6-CH3-, 4-CH3-6-CH2CH3-, 4-CH3-6-C6H5-, 4-CH3-6-CH(C The following are substituents: 6-C6H5-, 4-N(CH3)2-6-CH3-, 4-N(CH3)2-6-CH2CH3-, 4-N(CH3)2-6-C6H5-, 4-N(CH3)2-6-CH(C6H5)2-, 4-CF3-6-CH3-, 4-CF3-6-CH2CH3-, 4-CF3-6-C6H5-, 4-CF3-6-CH(C6H5)2-. In this invention, the number preceding the substituent refers to the substitution position on the pyridine ring. For example, 6-CH3- refers to a -CH3 substitution at position 6 on the pyridine ring.

[0052] In some embodiments of the present invention, R5 represents a substituent on the dihydrooxazole ring in Formula 3, allowing all the multiple substitution sites on the dihydrooxazole ring to be H, preferably R3 is H; or R3 represents that some of the substitution sites on the dihydrooxazole ring are substituents other than H, as mentioned above, the 4-position on the dihydrooxazole ring is monosubstituted, and the other substitution sites are H, preferably -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 monosubstituted on the 4-position of the dihydrooxazole ring, more specifically, having one of the following groups represented by the substitution sites on the dihydrooxazole ring: 4-CH3-, 4-CH2CH3-, 4-CH(CH3)2-, 4-C(CH3)3-, 4-C6H5-, 4-CH(C6H5)2-. In this invention, the number before the substituent refers to the substitution position on the dihydrooxazole ring. For example, 4-CH3- refers to the 4-CH3 substitution at the 4-position on the dihydrooxazole ring.

[0053] In some embodiments of the present invention, R2, R4, and R6 each independently represent substituents on the pyridine ring in Formulas 1, 2, and 3 (the pyridine ring in Formula 2 that is different from the one substituted by R3), allowing all the substitution sites on the pyridine ring substituted by R2, R4, and R6 to be H, preferably R2, R4, and R6 are all H; or, R2, R4, and R6 represent -Cl, -F, -CH3, -OCH3, -N(CH3)2, or -CF3 substituted at the 4-position on the substituted pyridine ring, more specifically, one of the following groups represented by the substitution site on the pyridine ring: 4-Cl-, 4-F-, 4-CH3-, 4-OCH3-, 4-N(CH3)2-, 4-CF3-. In the present invention, the number before the substituent refers to the substitution position on the pyridine ring; exemplarily, 4-Cl- refers to the 4-position substituted -Cl on the pyridine ring.

[0054] In some embodiments of the present invention, preferably, the molar ratio of the catalyst, the aluminum-containing co-catalyst-1 and the aluminum-containing co-catalyst-2 is 1:20-1000:15-1000, more preferably 1:40-900:20-900.

[0055] In this invention, when the molar ratio of the catalyst, the aluminum-containing co-catalyst-1, and the aluminum-containing co-catalyst-2 is controlled to meet the above-mentioned range, the reactivity of the polymerization reaction and copolymerization reaction in steps (1) and (2) can be controlled, thereby achieving control over the content of polyethylene segments and cis-butadiene segments in the ethylene-butadiene polymer, as well as the content of cis-1,4-structure in the cis-butadiene rubber.

[0056] In some specific embodiments of the present invention, preferably, the amount of catalyst used is 0.1-1.6 mmol / L relative to 1 mol of butadiene, more preferably 0.15-1.2 mmol / L. In the present invention, controlling the amount of catalyst and butadiene to satisfy the above-mentioned relationship ensures the polymerization activity of butadiene and enables the regulation of the content of each chain segment in the polymer.

[0057] In some specific embodiments of the present invention, preferably, the organic solvent is selected from at least one of n-pentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, benzene, toluene, decahydronaphthalene, dodecane, and hydrogenated gasoline, and is preferably toluene.

[0058] In some specific embodiments of the present invention, preferably, the polymerization reaction conditions include: a polymerization reaction temperature of 30-70℃, preferably 40-60℃; a polymerization reaction pressure of 1-10 bar, preferably 2-5 bar; and a polymerization reaction time of 1-6 h, preferably 2-5 h. In the present invention, the polymerization reaction pressure in step (1) can be the gas phase pressure of the butadiene monomer being fed.

[0059] In some specific embodiments of the present invention, preferably, the conditions for the copolymerization reaction include: a copolymerization reaction temperature of 20-70℃, preferably 30-60℃; a copolymerization reaction pressure of 1-70 bar, preferably 5-50 bar; and a copolymerization reaction time of 1-80 min, preferably 5-60 min. In the present invention, the copolymerization reaction pressure in step (2) can be the gas phase pressure of the fed ethylene monomer.

[0060] In some embodiments of the present invention, the amount of ethylene monomer and butadiene can be controlled by adjusting the reaction time and pressure to obtain an ethylene-butadiene polymer with cis-butadiene rubber as the elastomer matrix and polyethylene as the reinforcing phase. Preferably, the weight ratio of ethylene monomer and butadiene monomer feed satisfies the corresponding amounts of polyethylene and cis-butadiene rubber segments in the obtained ethylene-butadiene polymer. For example, based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segment is 0.1-40 wt%, preferably 1-35 wt%, and the content of the polyisoprene segment is 60-99.9 wt%, preferably 65-99 wt%; based on the total molar amount of the cis-butadiene rubber segment, the content of the cis-1,4-structure is 90-98.5 mol%, preferably 92-98 mol%.

[0061] In some specific embodiments of the present invention, preferably, the aluminum-containing co-catalyst-1 is selected from at least one of diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, di-n-propylaluminum dichloride, diisopropylaluminum dichloride, di-n-butylaluminum dichloride, diisobutylaluminum dichloride, di-octylaluminum dichloride, methylaluminoxane (MAO), and triisobutylaluminum-modified methylaluminoxane (MMAO), preferably at least one of diisobutylaluminum chloride, diethylaluminum chloride, sesquiethylaluminum, and methylaluminoxane. In the present invention, the polymerization reaction of butadiene monomer is initiated under the combined action of the catalyst and the aluminum-containing co-catalyst-1.

[0062] In some embodiments of the present invention, preferably, the aluminum-containing co-catalyst-2 is selected from at least one of methylaluminoxane (MAO), triisobutylaluminum-modified methylaluminoxane (MMAO), diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, di-n-propylaluminum dichloride, diisopropylaluminum dichloride, di-n-butylaluminum dichloride, diisobutylaluminum dichloride, and di-octylaluminum dichloride, and more preferably at least one of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diisobutylaluminum chloride, diethylaluminum chloride, and sesquiethylaluminum. In the present invention, under the combined action of the catalyst and the aluminum-containing co-catalyst-2, the copolymerization reaction between ethylene monomer and the active segments of polybutadiene is initiated.

[0063] In this invention, when the copolymerization reaction needs to be terminated, the following steps may also be included:

[0064] When the copolymerization reaction proceeds to the appropriate point, a stabilizer and a terminator are added sequentially to terminate the copolymerization reaction. The resulting product is then washed and vacuum dried to obtain the ethylene-reinforced cis-butadiene rubber.

[0065] The stabilizer can be an antioxidant, such as a 5% toluene solution of 2,2-methylenebis-(4-methyl-6-tert-butylphenol), added at a rate of 0.5%-1.0% of the total monomer weight. The terminator can terminate polymerization and remove residual catalyst, such as a 4% hydrochloric acid-methanol solution, added at a rate of 0.1%-1.0% of the total monomer weight. The washing process may involve sequentially using a methanol solution and water approximately three times.

[0066] In one specific embodiment of the present invention, the method for preparing the ethylene-butadiene polymer specifically includes the following steps:

[0067] The polymerization reaction environment is purified using a dual-pipe operation technique in the reaction equipment; the cobalt-based catalyst and organic solvent provided by this invention are added to the reaction equipment and stirred and dispersed evenly, and heated to the set temperature; then butadiene monomer is added to the reaction equipment, followed by a set amount of aluminum-containing co-catalyst-1 to initiate the polymerization reaction of butadiene until the set time is reached;

[0068] After the set polymerization reaction time is reached, aluminum-containing co-catalyst-2 is added, and ethylene gas at 1-70 bar is introduced to initiate the copolymerization reaction between ethylene monomers and polybutadiene active segments. Depending on the ethylene segment content in the final ethylene-butadiene polymer, the pressure is maintained at a constant level until the set time is reached.

[0069] Finally, stabilizers and terminators are added to terminate the reaction; the resulting product is then washed three times with methanol solution and vacuum dried to obtain the in-situ reinforced cis-butadiene rubber of polyethylene.

[0070] A third aspect of the present invention provides an ethylene-butadiene polymer prepared by the method of the present invention.

[0071] In this invention, the ethylene-butadiene polymer is as described in the first aspect of this invention, and will not be repeated here to avoid repetition.

[0072] A fourth aspect of the present invention provides a vulcanized rubber made from a composition comprising the ethylene-butadiene polymer described in the present invention.

[0073] The present invention will be described in detail below through embodiments. In the following embodiments,

[0074] The content of polyethylene segments in ethylene-butadiene polymers, the content of cis-butadiene rubber segments, the content of cis-1,4-structure in cis-butadiene rubber, and the content of polyethylene segments in toluene-insoluble matter were determined by nuclear magnetic resonance spectroscopy.

[0075] The number-average molecular weight and molecular weight distribution of the ethylene-butadiene polymer were determined using GPC.

[0076] The test for the content of toluene-insoluble matter refers to SH / T 1050-2014: Cut thin strips from multiple points in the obtained polymer sample, weigh approximately 0.3 g (accurate to 0.1 mg), and spread them evenly in a pre-weighed filter, ensuring the strips do not stick together. Add approximately 100 ml of toluene to the weighing bottle, and suspend the filter in the weighing bottle. Cap the weighing bottle and dissolve it at room temperature on a shaker for 48 hours. Then remove the filter, rinse several times, vacuum dry, and weigh.

[0077] All raw materials used in the examples and comparative examples are commercially available products.

[0078] Example 1

[0079] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is H (all substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 45°C, add 300g of 1,3-butadiene, maintain a constant pressure (3 bar) atmosphere, and inject diisobutylaluminum chloride (0.679 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 45°C and the polymerization reaction time is 2h.

[0080] The temperature of the mixing system was controlled at 30℃. After ethylene monomer was introduced to maintain a constant pressure (10 bar) atmosphere, methylaluminoxane (MAO) (0.679 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The polymerization temperature was 30℃, and the introduction of ethylene monomer was stopped after 10 min of polymerization.

[0081] Then, a 5% toluene solution of 2,2-methylenebis-(4-methyl-6-tert-butylphenol) was added as a stabilizer. Then, 20 mL of a 4% hydrochloric acid methanol solution was added to the polymerization system to terminate the reaction. Finally, the polymerization product was washed three times with methanol and then vacuum dried to obtain 282.8 g of ethylene-butadiene polymer.

[0082] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1650 and 736, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 7.3 wt%, cis-butadiene rubber segment content is 92.7 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 96.5 mol%;

[0083] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 220,000, and the molecular weight distribution is 3.08.

[0084] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 1 wt%, and based on the total weight of the toluene-insoluble matter, the polyethylene segment content is 93.2 wt%.

[0085] Example 2

[0086] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH(CH3)2- (other substitution sites on the benzene ring are hydrogen), R2 is 4-OCH3- (other substitution sites on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 42°C, add 500g of 1,3-butadiene, maintain a constant pressure (2.5 bar) atmosphere, and inject diisobutylaluminum chloride (0.679 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 42°C and the polymerization reaction time is 3h.

[0087] The temperature of the mixing system was controlled at 39°C. After ethylene monomer was introduced to maintain a constant pressure (7 bar) atmosphere, methylaluminoxane (MAO) (0.452 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 39°C. After copolymerization for 6 minutes, the introduction of ethylene monomer was stopped.

[0088] The polymerization product was post-processed according to the method in Example 1 to obtain 454.1 g of ethylene-butadiene polymer.

[0089] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1644 and 734, and polyethylene segment at wavenumber of 719); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 1.7 wt%, cis-butadiene rubber segment content is 98.3 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 98 mol%;

[0090] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 363,000, and the molecular weight distribution is 2.79.

[0091] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 0.3 wt%, and the polyethylene segment content is 94.8 wt% based on the total weight of the toluene-insoluble matter.

[0092] Example 3

[0093] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 3L of toluene and the catalyst shown in Formula 1 (where R1 is 2,4,6-CH3- (other substitution sites on the benzene ring are hydrogen), R2 is 4-F- (other substitution sites on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 48°C, add 650g of 1,3-butadiene, maintain a constant pressure (3.2 bar) atmosphere, and inject diisobutylaluminum chloride (0.679 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 48°C and the polymerization reaction time is 3.5h.

[0094] The temperature of the mixing system was controlled at 35℃. After ethylene monomer was introduced to maintain a constant pressure (15 bar) atmosphere, diethylaluminum chloride (0.113 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 35℃ and the copolymerization reaction time was 25 min. Then the introduction of ethylene monomer was stopped.

[0095] The polymerization product was post-processed according to the method in Example 1 to obtain 607.9 g of ethylene-butadiene polymer.

[0096] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1644 and 738, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.1); polyethylene segment content is 3.6 wt%, cis-butadiene rubber segment content is 96.4 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 97 mol%;

[0097] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 479,000, and the molecular weight distribution is 2.95.

[0098] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 0.9 wt%, and the polyethylene segment content is 94.1 wt% based on the total weight of the toluene-insoluble matter.

[0099] Example 4

[0100] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH2CH3- (other substitution sites on the benzene ring are hydrogen), R2 is 4-CH3- (other substitution sites on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 52°C, add 200g of 1,3-butadiene, maintain a constant pressure (4 bar) atmosphere, and inject diisobutylaluminum chloride (1.131 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 43°C and the polymerization reaction time is 4h.

[0101] The temperature of the mixing system was controlled at 40℃. After ethylene monomer was introduced to maintain a constant pressure (8.5 bar) atmosphere, methylaluminoxane (MAO) (1.131 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 40℃ and the copolymerization reaction time was 9 min. Then the introduction of ethylene monomer was stopped.

[0102] The polymerization product was post-processed according to the method in Example 1 to obtain 202.9 g of ethylene-butadiene polymer.

[0103] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1(Characteristic peaks of cis-butadiene rubber at wavenumbers of 1649 and 741, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 10.3 wt%, cis-butadiene rubber segment content is 89.7 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 96.1 mol%;

[0104] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 148,000, and the molecular weight distribution is 3.31.

[0105] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 1.3 wt%, and the polyethylene segment content is 92.3 wt% based on the total weight of the toluene-insoluble matter.

[0106] Example 5

[0107] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH2CH3- (other substitution sites on the benzene ring are hydrogen), R2 is 4-Cl- (other substitution sites on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 53°C, add 280g of 1,3-butadiene, maintain a constant pressure (3 bar) atmosphere, and inject diisobutylaluminum chloride (1.584 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 53°C and the polymerization reaction time is 3h.

[0108] The temperature of the mixing system was controlled at 33℃. After ethylene monomer was introduced to maintain a constant pressure (5 bar) atmosphere, methylaluminoxane (MAO) (1.584 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The polymerization temperature was 33℃, and the introduction of ethylene monomer was stopped after 20 min of polymerization.

[0109] The polymerization product was post-processed according to the method in Example 1 to obtain 277.5 g of ethylene-butadiene polymer.

[0110] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1648 and 737, and polyethylene segment at wavenumber of 723); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 5.4 wt%, cis-butadiene rubber segment content is 94.6 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 97.1 mol%;

[0111] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 198,000, and the molecular weight distribution is 3.02.

[0112] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 0.7 wt%, and the polyethylene segment content is 93.6 wt% based on the total weight of the toluene-insoluble matter.

[0113] Example 6

[0114] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 2 (where R3 is 4,6-CH3- (the other substitution sites on the pyridine ring substituted by R3 are hydrogen), R4 is hydrogen (all substitution sites on the pyridine ring substituted by R4 are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 58°C, add 300g of 1,3-butadiene, maintain a constant pressure (3.5 bar) atmosphere, and inject diisobutylaluminum chloride (1.131 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 58°C and the polymerization reaction time is 4h.

[0115] The temperature of the mixing system was controlled at 60℃. After ethylene monomer was introduced to maintain a constant pressure (50 bar) atmosphere, methylaluminoxane (MAO) (1.131 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The polymerization temperature was 60℃ and the polymerization reaction time was 19 min before the introduction of ethylene monomer was stopped.

[0116] The polymerization product was post-processed according to the method in Example 1 to obtain 451.8 g of ethylene-butadiene polymer.

[0117] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1639 and 739, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 25.1 wt%, cis-butadiene rubber segment content is 74.9 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 93.7 mol%;

[0118] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 275,000, and the molecular weight distribution is 3.98.

[0119] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 5.1 wt%, and the polyethylene segment content is 87.1 wt% based on the total weight of the toluene-insoluble matter.

[0120] Example 7

[0121] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 2 (wherein, R3 is 4-N(CH3)2-6-CH2CH3- (the other substitution sites on the pyridine ring substituted by R3 are hydrogen), R4 is 4-OCH3- (the other substitution sites on the pyridine ring substituted by R4 are hydrogen), and X is bromine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 60°C, add 460g of 1,3-butadiene, maintain a constant pressure (3.5 bar) atmosphere, and inject diisobutylaluminum chloride (0.684 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 60°C and the polymerization reaction time is 4.8h.

[0122] The temperature of the mixing system was controlled at 50℃. After ethylene monomer was introduced to maintain a constant pressure (30 bar) atmosphere, diethylaluminum chloride (0.684 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization temperature was 50℃ and the copolymerization reaction time was 40 min before the introduction of ethylene monomer was stopped.

[0123] The polymerization product was post-processed according to the method in Example 1 to obtain 588.0 g of ethylene-butadiene polymer.

[0124] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1649 and 729, and polyethylene segment at wavenumber of 719); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 28.5 wt%, cis-butadiene rubber segment content is 71.5 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 93.6 mol%;

[0125] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 474,000, and the molecular weight distribution is 4.11.

[0126] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 8.4 wt%, and the polyethylene segment content is 86.4 wt% based on the total weight of the toluene-insoluble matter.

[0127] Example 8

[0128] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 2 (where R3 is 4-CF3-6-C6H5- (the other substitution sites on the pyridine ring substituted by R3 are hydrogen), R4 is 4-F- (the other substitution sites on the pyridine ring substituted by R4 are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 55°C, add 180g of 1,3-butadiene, maintain a constant pressure (2.5 bar) atmosphere, and inject diisobutylaluminum chloride (1.584 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 55°C and the polymerization reaction time is 3.2h.

[0129] The temperature of the mixing system was controlled at 55℃. After ethylene monomer was introduced to maintain a constant pressure (20 bar) atmosphere, methylaluminoxane (MAO) (1.584 mol) was added to initiate the polymerization of ethylene and polybutadiene. The polymerization temperature was 55℃, and the copolymerization reaction time was 30 min before the introduction of ethylene monomer was stopped.

[0130] The polymerization product was post-processed according to the method in Example 1 to obtain 228.9 g of ethylene-butadiene polymer.

[0131] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1646 and 741, and polyethylene segment at wavenumber of 722); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 31.6 wt%, cis-butadiene rubber segment content is 68.4 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 93.2 mol%;

[0132] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 153,000, and the molecular weight distribution is 4.25.

[0133] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 5.3 wt%, and the polyethylene segment content is 85.7 wt% based on the total weight of the toluene-insoluble matter.

[0134] Example 9

[0135] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 1L of toluene and the catalyst shown in Formula 2 (wherein, R3 is 6-CH(C6H5)2- (the other substitution sites on the pyridine ring substituted by R3 are hydrogen), R4 is 4-Cl (the other substitution sites on the pyridine ring substituted by R4 are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 50°C, add 150g of 1,3-butadiene, maintain a constant pressure (2.5 bar) atmosphere, and inject methylaluminoxane (MAO) (0.678 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 50°C and the polymerization reaction time is 2.4h.

[0136] The temperature of the mixing system was controlled at 47°C. After ethylene monomer was introduced to maintain a constant pressure (15 bar) atmosphere, methylaluminoxane (MAO) (0.452 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization temperature was 47°C and the copolymerization reaction time was 15 min. Then the introduction of ethylene monomer was stopped.

[0137] The polymerization product was post-processed according to the method in Example 1 to obtain 146.3 g of ethylene-butadiene polymer.

[0138] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1647 and 731, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 13.9 wt%, cis-butadiene rubber segment content is 86.1 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 96 mol%;

[0139] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 101,000, and the molecular weight distribution is 3.45.

[0140] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 1.6 wt%, and the polyethylene segment content is 91.5 wt% based on the total weight of the toluene-insoluble matter.

[0141] Example 10

[0142] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 3 (where R5 is 4-CH3- (other substitution sites on the dihydrooxazole ring are hydrogen), R6 is H (other substitution sites on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 48°C, add 190g of 1,3-butadiene, maintain a constant pressure (2.7 bar) atmosphere, and inject methylaluminoxane (MAO) (0.678 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 50°C and the polymerization reaction time is 4.2h.

[0143] The temperature of the mixing system was controlled at 32℃. After ethylene monomer was introduced to maintain a constant pressure (25 bar) atmosphere, methylaluminoxane (MAO) (0.452 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization temperature was 32℃ and the copolymerization reaction time was 25 min. Then the introduction of ethylene monomer was stopped.

[0144] The polymerization product was post-processed according to the method in Example 1 to obtain 210.8 g of ethylene-butadiene polymer.

[0145] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1648 and 741, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 22.5 wt%, cis-butadiene rubber segment content is 77.5 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 94 mol%;

[0146] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 148,000, and the molecular weight distribution is 3.83.

[0147] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 3.2 wt%, and the polyethylene segment content is 88.2 wt% based on the total weight of the toluene-insoluble matter.

[0148] Example 11

[0149] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 3L of toluene and the catalyst shown in Formula 3 (where R5 is 4-CH2CH3- (other substituents on the dihydrooxazole ring are hydrogen), R6 is 4-CH3- (other substituents on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 45°C, add 410g of 1,3-butadiene, maintain a constant pressure (2.5 bar) atmosphere, and inject diisobutylaluminum chloride (0.226 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 45°C and the polymerization reaction time is 5h.

[0150] The temperature of the mixing system was controlled at 42℃. After ethylene monomer was introduced to maintain a constant pressure (6 bar) atmosphere, methylaluminoxane (MAO) (0.339 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization temperature was 42℃ and the copolymerization time was 50 min. Then the introduction of ethylene monomer was stopped.

[0151] The polymerization product was post-processed according to the method in Example 1 to obtain 383.5 g of ethylene-butadiene polymer.

[0152] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1647 and 738, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 11.3 wt%, cis-butadiene rubber segment content is 88.7 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 95.9 mol%;

[0153] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 258,000, and the molecular weight distribution is 3.42.

[0154] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 2.0 wt%, and the polyethylene segment content is 92.1 wt% based on the total weight of the toluene-insoluble matter.

[0155] Example 12

[0156] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 4L of toluene and the catalyst shown in Formula 3 (where R5 is 4-CH(CH3)2- (other substituents on the dihydrooxazole ring are hydrogen), R6 is 4-OCH3- (other substituents on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 45°C, add 150g of 1,3-butadiene, maintain a constant pressure (2.7 bar) atmosphere, and inject diisobutylaluminum chloride (0.113 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 45°C and the polymerization reaction time is 4.5h.

[0157] The temperature of the mixing system was controlled at 50℃. After ethylene monomer was introduced to maintain a constant pressure (40 bar) atmosphere, sesquiethylaluminum (0.904 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 50℃ and the copolymerization reaction time was 22 min. Then the introduction of ethylene monomer was stopped.

[0158] The polymerization product was post-processed according to the method in Example 1 to obtain 186.9 g of ethylene-butadiene polymer.

[0159] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1649 and 733, and polyethylene segment at wavenumber of 722); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 34.2 wt%, cis-butadiene rubber segment content is 65.8 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 92.3 mol%;

[0160] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 138,000, and the molecular weight distribution is 4.35.

[0161] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 4.3 wt%, and the polyethylene segment content is 85.2 wt% based on the total weight of the toluene-insoluble matter.

[0162] Example 13

[0163] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 3 (where R5 is 4-C6H5- (other substituents on the dihydrooxazole ring are hydrogen), R6 is 4-CF3- (other substituents on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 40°C, add 480g of 1,3-butadiene, maintain a constant pressure (2.7 bar) atmosphere, and inject diisobutylaluminum chloride (0.791 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 40°C and the polymerization reaction time is 4.7 h.

[0164] The temperature of the mixing system was controlled at 45℃. After ethylene monomer was introduced to maintain a constant pressure (35 bar) atmosphere, methylaluminoxane (MAO) (1.131 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 45℃ and the copolymerization reaction time was 36 min. Then the introduction of ethylene monomer was stopped.

[0165] The polymerization product was post-processed according to the method in Example 1 to obtain 509.0 g of ethylene-butadiene polymer.

[0166] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1646 and 738, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 17.1 wt%, cis-butadiene rubber segment content is 82.9 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 94.5 mol%;

[0167] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 352,000, and the molecular weight distribution is 3.63.

[0168] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 4.0 wt%, and the polyethylene segment content is 90.9 wt% based on the total weight of the toluene-insoluble matter.

[0169] Example 14

[0170] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 45°C, add 520g of 1,3-butadiene, maintain a constant pressure (2.7 bar) atmosphere, and inject diisobutylaluminum chloride (1.357 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 45°C and the polymerization reaction time is 4.7 h.

[0171] The temperature of the mixing system was controlled at 38℃. After ethylene monomer was introduced to maintain a constant pressure (42 bar) atmosphere, methylaluminoxane (MAO) (1.131 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 38℃ and the copolymerization reaction time was 60 min. Then the introduction of ethylene monomer was stopped.

[0172] The polymerization product was post-processed according to the method in Example 1 to obtain 594.0 g of ethylene-butadiene polymer.

[0173] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1647 and 738, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 20.4 wt%, cis-butadiene rubber segment content is 79.6 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 94.2 mol%;

[0174] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 416,000, and the molecular weight distribution is 3.75.

[0175] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 5.3 wt%, and the polyethylene segment content is 89.6 wt% based on the total weight of the toluene-insoluble matter.

[0176] Example 15

[0177] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH2CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 43°C, add 480g of 1,3-butadiene, maintain a constant pressure (2.7 bar) atmosphere, and inject diisobutylaluminum chloride (1.131 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 43°C and the polymerization reaction time is 3.9h.

[0178] The temperature of the mixing system was controlled at 45℃. After ethylene monomer was introduced to maintain a constant pressure (18 bar) atmosphere, sesquiethylaluminum (0.452 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization temperature was 45℃ and the copolymerization reaction time was 32 min. Then the introduction of ethylene monomer was stopped.

[0179] The polymerization product was post-processed according to the method in Example 1 to obtain 440.8 g of ethylene-butadiene polymer.

[0180] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1647 and 741, and polyethylene segment at wavenumber of 722); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 8.8 wt%, cis-butadiene rubber segment content is 91.2 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 96.3 mol%;

[0181] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 312,000, and the molecular weight distribution is 3.19.

[0182] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 1.6 wt%, and the polyethylene segment content is 92.6 wt% based on the total weight of the toluene-insoluble matter.

[0183] Comparative Example 1

[0184] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 = 2,4,6-CH3- (other substituents on the benzene ring are hydrogen), R2 is H (all substituents on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 55°C, add 420g of 1,3-butadiene, maintain a constant pressure (3 bar) atmosphere, and inject diisobutylaluminum chloride (1.584 mol) to initiate the polymerization of butadiene monomer. The reaction time is 4h.

[0185] The polymerization product was post-treated according to the method in Example 1 to obtain 381.4 g of cis-butadiene rubber.

[0186] (2) The obtained cis-butadiene rubber was characterized by FT-IR (KBr, cm⁻¹). -1 (characteristic peaks of cis-butadiene rubber with wavenumbers of 1644 and 739); 1H NMR spectrum (ppm) (cis-butadiene rubber peak with chemical shift of 5.4); cis-butadiene rubber segment content is 100 wt%; cis-1,4-structure content is 98.2 mol%.

[0187] According to GPC test data, the number-average molecular weight of this butadiene rubber is 147,000, and the molecular weight distribution is 2.68.

[0188] No toluene insoluble matter.

[0189] Comparative Example 2

[0190] 124.6 g of a polyethylene-cis-butadiene rubber blend was prepared by solution blending of the butadiene rubber obtained in Comparative Example 1 and polyethylene, wherein the polyethylene content was 7.3 wt% based on the total weight of the blend.

[0191] The toluene-insoluble matter test data shows that the toluene-insoluble matter content in the blend is 7.3 wt%, and the polyethylene segment content is 100 wt% based on the total weight of the toluene-insoluble matter.

[0192] Comparative Example 3

[0193] 100.6 g of a polyethylene-cis-butadiene rubber blend was prepared by solution blending of the butadiene rubber obtained in Comparative Example 1 and polyethylene, wherein the polyethylene content was 10.3 wt% based on the total weight of the blend.

[0194] The toluene-insoluble matter test data shows that the toluene-insoluble matter content in this blend is 10.3 wt%, and the polyethylene segment content is 100 wt% based on the total weight of the toluene-insoluble matter.

[0195] Comparative Example 4

[0196] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH2CH3- (other substitution sites on the benzene ring are hydrogen), R2 is 4-CH3- (other substitution sites on the pyridine ring are hydrogen), and X is bromine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 52°C, add 200g of 1,3-butadiene, maintain a constant pressure (4 bar) atmosphere, and inject diisobutylaluminum chloride (1.131 mol) to initiate the butadiene polymerization reaction. The polymerization reaction temperature is 43°C and the polymerization reaction time is 4h.

[0197] The temperature of the mixing system was controlled at 40℃. After ethylene monomer was introduced to maintain a constant pressure (20 bar) atmosphere, methylaluminoxane (MAO) (1.131 mol) was added to initiate the copolymerization of ethylene and polybutadiene. The copolymerization reaction temperature was 40℃ and the copolymerization reaction time was 30 min. Then the introduction of ethylene monomer was stopped.

[0198] The polymerization product was post-processed according to the method in Example 1 to obtain 355.5 g of ethylene-butadiene polymer.

[0199] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1649 and 741, and polyethylene segment at wavenumber of 721); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 44.3 wt%, cis-butadiene rubber segment content is 55.7 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 91.8 mol%;

[0200] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 228,000, and the molecular weight distribution is 5.24.

[0201] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 10 wt%, and the polyethylene segment content is 84.2 wt% based on the total weight of the toluene-insoluble matter.

[0202] Comparative Example 5

[0203] (1) After circulating the polymerization equipment three times using the double-row tube operation technique, add 2L of toluene and the catalyst shown in Formula 1 (where R1 is 2,6-CH(CH3)2- (other substitution positions on the benzene ring are hydrogen), R2 is H (all substitution positions on the pyridine ring are hydrogen), and X is chlorine) (2.260 mmol). Use mechanical stirring to quickly disperse the mixture evenly. Heat the evenly dispersed mixture to 45°C, inject diisobutylaluminum chloride (0.679 mol) and methylaluminoxane (MAO) (0.679 mol), add 300g of 1,3-butadiene, and purify the ethylene monomer to maintain a constant pressure (10 bar). The polymerization temperature is 40°C. After polymerization for 10 min, stop purging the ethylene monomer. The reaction time is 3 hours.

[0204] The polymerization product was post-processed according to the method in Example 1 to obtain 268.4 g of ethylene-butadiene polymer.

[0205] (2) Characterization of the obtained ethylene-butadiene polymer: FT-IR (KBr, cm -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1650 and 736, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); polyethylene segment content is 6.7 wt%, cis-butadiene rubber segment content is 93.3 wt%; among the cis-butadiene rubber segments, the content of cis-1,4-structure is 85.8 mol%;

[0206] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 68,000, and the molecular weight distribution is 3.22.

[0207] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 0.2 wt%, and the polyethylene segment content is 93.2 wt% based on the total weight of the toluene-insoluble matter.

[0208] Comparative Example 6

[0209] Take 200g of the ethylene-butadiene polymer obtained in Example 6, add about 2L of toluene, and stir at room temperature for 48 hours until no obvious solids are visible. Filter through a stainless steel mesh with a pore size of 125 micrometers. Wash the filtrate three times with methanol and then dry under vacuum to obtain 184.7g of ethylene-butadiene polymer D6.

[0210] The obtained ethylene-butadiene polymer was characterized by FT-IR (KBr, cm⁻¹). -1(Characteristic peaks of cis-butadiene rubber at wavenumbers of 1650 and 736, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); content of polyethylene segment is 21.1 wt%, content of cis-butadiene rubber segment is 78.9 wt%; content of cis-1,4-structure in cis-butadiene rubber segment is 93.7 mol%;

[0211] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 282,000, and the molecular weight distribution is 3.89.

[0212] No toluene insoluble matter.

[0213] Comparative Example 7

[0214] A 300 mL solution of toluene containing 13.5 g (0.25 mol) of 1,3-butadiene was added to a thoroughly dried 400 mL pressure-resistant glass reactor, and ethylene was then introduced into the reactor at 0.4 MPa. Simultaneously, in a glove box under nitrogen atmosphere, 18.0 μmol of bis(2-phenylindenyl)gadolinium bis(dimethylsilylamide) [(2-PhC9H6)2GdN(SiHMe2)2], 36.0 μmol of dimethylaniline tetra(pentafluorophenyl)borate (Me2NHPhB(C6F5)4), and 0.90 mmol of diisobutylaluminum hydride were dissolved in 10 mL of toluene to obtain a catalyst solution. The catalyst solution was then removed from the glove box, and a catalyst solution converted to 17.5 μmol of gadolinium was added to the monomer solution, followed by polymerization at room temperature for 180 minutes. After polymerization, the polymerization product was post-processed according to the method of Example 1 to obtain copolymer D7 11.7g.

[0215] The obtained ethylene-butadiene polymer was characterized by FT-IR (KBr, cm⁻¹). -1 (Characteristic peaks of cis-butadiene rubber at wavenumbers of 1650 and 736, and polyethylene segment at wavenumber of 720); 1H NMR spectrum (ppm) (cis-butadiene rubber peak at chemical shift of 5.4, ethylene segment peak at 1.10); content of polyethylene segment is 11.2 wt%, content of cis-butadiene rubber segment is 88.8 wt%; content of cis-1,4-structure in cis-butadiene rubber segment is 97.7 mol%.

[0216] According to GPC test data, the number-average molecular weight of this ethylene-butadiene polymer is 177,000, and the molecular weight distribution is 1.93.

[0217] According to the toluene-insoluble matter test data, the toluene-insoluble matter content in this ethylene-butadiene polymer is 0.1 wt%, and the polyethylene segment content is 83.4 wt% based on the total weight of the toluene-insoluble matter.

[0218] As can be seen from the examples and comparative examples, with the increase of ethylene segment content in the polymer, the content of cis-1,4-structure of butadiene segment slightly decreases but remains above 92%, the molecular weight is between 80,000 and 500,000, and the molecular weight distribution shows a broadening trend but remains below 4.5. Furthermore, the polymers obtained in Examples 1-15 were prepared by in-situ polymerization, and the content of toluene-insoluble matter in the obtained polymers was 0.3-9 wt%.

[0219] Comparative Example 1 was cis-1,4-polybutadiene, without polyethylene segments. Comparative Examples 2 and 3 were blends of polyethylene and cis-butadiene rubber with the same ethylene content as Examples 1 and 4. In Comparative Example 4, the ethylene segment content exceeded 40%, the cis-1,4-structure content of the butadiene segments decreased to below 92%, and the polymer distribution was further broadened to 5.24. In Comparative Example 5, by adding ethylene and butadiene monomers together, the resulting polymer had a further reduced cis-1,4-structure content to 85.8% and a lower molecular weight.

[0220] In Comparative Example 1, there was no toluene-insoluble matter. In Comparative Examples 2 and 3, toluene-insoluble polyethylene was added through physical mixing. The polymer in Comparative Example 4 had a relatively high toluene-insoluble matter content, while the polymer in Comparative Example 5 had a relatively low toluene-insoluble matter content. In Comparative Example 6, compared to Example 6, after filtration through a stainless steel mesh, the polyethylene segment content of the polymer decreased, and there was no toluene-insoluble matter. In Comparative Example 7, the polymer had a relatively low toluene-insoluble matter content.

[0221] Test case

[0222] Mixing and vulcanization: The ethylene-butadiene polymer obtained in Example 1, and the blends of cis-butadiene rubber, polyethylene, and cis-butadiene rubber obtained in the comparative example were prepared into vulcanized rubber samples by the following methods:

[0223] Mixing process: All vulcanized rubber formulations were mixed in a HaproRM-200A torque rheometer (Harbin Hapro Electric Technology Co., Ltd.). The mixed samples were passed through a two-roll mill 20 times to obtain the final mixed rubber. The mixing process is shown in Table 1.

[0224] Preparation of vulcanized rubber samples: After the obtained compound was left to stand at room temperature for 24 hours, it was placed in a processing template and vulcanized in an XLB-D350×350 flat vulcanizing machine with the vulcanization temperature set at 150℃ and the vulcanization time set at t90.

[0225] Table 1

[0226] Add time (min) Additives and fillers (parts by weight) 0-1 Polymer, 100 parts 1-2 ZnO, 4 parts; stearic acid, 1.5 parts 2-3 4010NA, 1 copy 3-6 N330, 45 copies 6-7 CZ, 1 part; D, 0.5 parts 7-13 Mix 13-14 Sulfur S, 1.5 parts 14-15 Finish

[0227] The tensile strength and tear strength of the vulcanized rubber samples were measured. The tensile strength was determined according to standard GB / T 528-1998, and the tear strength was determined according to standard GB / T529-1999. The results are shown in Table 2.

[0228] Table 2

[0229]

[0230]

[0231] The results in Table 2 and the comparison with comparative examples show that the polyethylene-reinforced cis-butadiene rubber prepared by the one-step polymerization method of this invention in Examples 1-15 exhibits higher fracture strength and tear strength in the vulcanizate, demonstrating a better reinforcing effect. With increasing polyethylene content, the fracture strength and tear strength of the vulcanizate show an upward trend. Compared to Comparative Examples 2-3, the polymers with the same ethylene content also show higher fracture strength and tear strength. Simultaneously, with increasing number-average molecular weight, the fracture strength and tear strength of the vulcanizate also show an upward trend. In Comparative Example 4, with further increasing ethylene segment content, the tear strength remained high, but the fracture strength decreased. Due to the low molecular weight of the polymer obtained in Comparative Example 5, the fracture strength and tear strength of the vulcanizate are not high. In Comparative Example 6, after the toluene-insoluble matter removal process, the mechanical properties of the obtained polymer vulcanizate decreased, lower than those in Example 6 and Example 11 with even lower polyethylene segment content, indicating that toluene-insoluble matter has a better reinforcing effect in the vulcanizate, improving both fracture strength and tear strength. In Comparative Example 7, although the content of polyethylene segments in the ethylene-butadiene polymer was comparable to that in Example 11 and higher than that in Example 15 and Example 4, the lower content of toluene-insoluble matter in Comparative Example 7 resulted in lower fracture strength and tear strength of its vulcanizate compared to Examples 4, 11 and 15.

[0232] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An ethylene-butadiene polymer, characterized in that, The ethylene-butadiene polymer comprises polyethylene segments and cis-butadiene rubber segments; based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segments is 0.1-40 wt%, and the content of the cis-butadiene rubber segments is 60-99.9 wt%; in the cis-butadiene rubber segments, based on the total molar amount of the cis-butadiene rubber segments, the content of the cis-1,4-structure is 90-98.5 mol%; based on the total weight of the ethylene-butadiene polymer, the content of toluene-insoluble matter is 0.2-10 wt%.

2. The ethylene-butadiene polymer according to claim 1, wherein, Based on the total weight of the ethylene-butadiene polymer, the content of the polyethylene segment is 1-35 wt%, and the content of the cis-butadiene segment is 65-99 wt%.

3. The ethylene-butadiene polymer according to claim 1, wherein, In the butadiene rubber segment, based on the total molar amount of the butadiene rubber segment, the content of cis-1,4-structure is 92-98 mol.

4. The ethylene-butadiene polymer according to any one of claims 1-3, wherein, The number-average molecular weight of the ethylene-butadiene polymer is 50,000 to 700,000.

5. The ethylene-butadiene polymer according to claim 4, wherein, The number-average molecular weight of the ethylene-butadiene polymer is 80,000 to 500,000.

6. The ethylene-butadiene polymer according to any one of claims 1-3, wherein, The molecular weight distribution of the ethylene-butadiene polymer is 2-5.

7. The ethylene-butadiene polymer according to claim 6, wherein, The molecular weight distribution of the ethylene-butadiene polymer is 2.5-4.

5.

8. The ethylene-butadiene polymer according to any one of claims 1-3, wherein, Based on the total weight of the ethylene-butadiene polymer, the content of toluene-insoluble matter is 0.3-9 wt%.

9. The ethylene-butadiene polymer according to claim 8, wherein, Based on the total amount of toluene-insoluble matter, the content of polyethylene segments is 85-95 wt%.

10. A method for preparing the ethylene-butadiene polymer according to any one of claims 1-9, characterized in that, The method includes the following steps: (1) In the presence of organic solvent and catalyst, butadiene monomer is polymerized by aluminum-containing co-catalyst-1 to obtain polybutadiene product; (2) Add aluminum-containing co-catalyst-2 to the polymerization system obtained in step (1), and then introduce ethylene monomer and polybutadiene active chain segment in the polybutadiene product to carry out copolymerization reaction to obtain the ethylene-butadiene polymer.

11. The method according to claim 10, wherein, In step (1), the catalyst is a cobalt-containing organic compound.

12. The method according to claim 11, wherein, In step (1), the catalyst is selected from at least one of the compounds shown in Formula 1, Formula 2, and Formula 3: Formula 1 Formula 2 Formula 3; Where X is chlorine or bromine; R1 is H, or a monosubstituted group at the 2 or 4 position of the benzene ring, or a monosubstituted group at the 2, 4 or 2, 6 position of the benzene ring, or a trisubstituted group at the 2, 4, 6 position of the benzene ring, and the substituent is -F, -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2; R3 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with a monosubstituted 6-position on the pyridine ring, or -CH3, -N(CH3)2 or -CF3 with a monosubstituted 4-position on the pyridine ring, or the same or different -CH3, -CH2CH3, -C6H5, -CH(C6H5)2, -N(CH3)2 or -CF3 with double substitutions at the 4 and 6 positions on the pyridine ring; R5 is H, or -CH3, -CH2CH3, -CH(CH3)2, -C(CH3)3, -C6H5 or -CH(C6H5)2 with a monosubstituted 4-position on the dihydrooxazole ring; R2, R4, and R6 are each independently hydrogen, or monosubstituted at the 4-position of the pyridine ring with -Cl, -F, -CH3, -OCH3, -N(CH3)2, or -CF3.

13. The method according to claim 10, wherein, The catalyst: the molar ratio of the aluminum-containing co-catalyst-1 to the aluminum-containing co-catalyst-2 is 1:20-1000:15-1000.

14. The method according to claim 13, wherein, The catalyst: the molar ratio of the aluminum-containing co-catalyst-1 to the aluminum-containing co-catalyst-2 is 1:40-900:20-900.

15. The method according to claim 10, wherein, The amount of catalyst used is 0.1-1.6 mmol relative to 1 mol of butadiene.

16. The method according to claim 15, wherein, The amount of catalyst used is 0.15-1.2 mmol relative to 1 mol of butadiene.

17. The method according to claim 10, wherein, The organic solvent is selected from at least one of n-pentane, neopentane, n-hexane, cyclohexane, n-heptane, n-octane, isooctane, benzene, toluene, decahydronaphthalene, dodecane, and hydrogenated gasoline.

18. The method according to claim 17, wherein, The organic solvent is toluene.

19. The method according to claim 10, wherein, The conditions for the polymerization reaction include a polymerization temperature of 30-70℃.

20. The method according to claim 19, wherein, The polymerization reaction temperature is 40-60℃.

21. The method according to claim 10, wherein, The conditions for the polymerization reaction include a polymerization pressure of 1-10 bar.

22. The method according to claim 21, wherein, The polymerization reaction pressure is 2-5 bar.

23. The method according to claim 10, wherein, The conditions for the polymerization reaction include a polymerization reaction time of 1-6 hours.

24. The method according to claim 23, wherein, The polymerization reaction time is 2-5 hours.

25. The method according to claim 10, wherein, The conditions for the copolymerization reaction include a copolymerization temperature of 20-70℃.

26. The method of claim 25, wherein, The copolymerization reaction temperature is 30-60℃.

27. The method according to claim 10, wherein, The conditions for the copolymerization reaction include a copolymerization reaction pressure of 1-70 bar.

28. The method according to claim 27, wherein, The copolymerization reaction pressure is 5-50 bar.

29. The method according to claim 10, wherein, The conditions for the copolymerization reaction include: a copolymerization reaction time of 1-80 min.

30. The method according to claim 29, wherein, The copolymerization reaction time is 5-60 min.

31. The method according to claim 10, wherein, The aluminum-containing co-catalyst-1 is selected from at least one of diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, di-n-propylaluminum dichloride, diisopropylaluminum dichloride, di-n-butylaluminum dichloride, diisobutylaluminum dichloride, di-n-octylaluminum dichloride, methylaluminoxane, and triisobutylaluminum-modified methylaluminoxane.

32. The method according to claim 31, wherein, The aluminum-containing co-catalyst-1 is at least one of diisobutylaluminum chloride, diethylaluminum chloride, sesquiethylaluminum and methylaluminoxane.

33. The method according to claim 10, wherein, The aluminum-containing co-catalyst-2 is selected from at least one of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diethylaluminum chloride, sesquiethylaluminum, di-n-propylaluminum chloride, diisopropylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, di-n-octylaluminum chloride, ethylaluminum dichloride, di-n-propylaluminum dichloride, diisopropylaluminum dichloride, di-n-butylaluminum dichloride, diisobutylaluminum dichloride, and di-n-octylaluminum dichloride.

34. The method according to claim 33, wherein, The aluminum-containing co-catalyst-2 is at least one of methylaluminoxane, triisobutylaluminum-modified methylaluminoxane, diisobutylaluminum chloride, diethylaluminum chloride, and sesquiethylaluminum.

35. An ethylene-butadiene polymer prepared by the method according to any one of claims 10-34.

36. A vulcanized rubber made from a composition comprising the ethylene-butadiene polymer of any one of claims 1-9 and 35.

Images