Closed loop half sandwich type hindered alpha-diimine cationic nickel catalyst, method of making and method of making ultra-high molecular weight bimodal polyethylene

Abstract

The application provides a cationic nickel complex shown in formula (II) and a preparation method and application thereof. By closing a semi- sandwich type ring structure and containing an axial phenyl ring η 6 Coordination, an electronic effect and space steric hindrance of the axial phenyl ring to the cationic nickel metal center are regulated. In a single active center, the catalyst simultaneously forms two kinds of active centers with high steric hindrance and low steric hindrance, and can directly obtain a bimodal distribution ultrahigh molecular weight polyethylene thermoplastic elastomer in a single reactor by one-step catalysis of ethylene polymerization. Experiments show that the catalyst prepared in the application exhibits high activity under mild conditions, and can regulate the molecular weight distribution of the product. The obtained bimodal polyethylene has high strength, high elasticity of the high molecular weight component and good processing fluidity of the low molecular weight component, and has a moderate branching degree, thereby realizing excellent comprehensive performance, significantly improving the processing process, and having outstanding industrial application potential and market prospect.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a closed-ring semi-sandwich type with large steric hindrance. α - Diimine cationic nickel catalyst and its preparation method and preparation method of ultra-high molecular weight bimodal polyethylene. Background Technology

[0002] Ultra-high molecular weight (UHMW) polymers typically contain more than 15,000 to 20,000 repeating units and have a molecular weight exceeding 10. 6 With g / mol, it possesses excellent tensile strength, superior toughness, outstanding chemical inertness, and excellent wear resistance, and has a wide range of applications in many fields such as biomedical implants, bulletproof armor, high-performance textiles, industrial wear parts, and aerospace engineering.

[0003] Over the past few decades, polyolefin thermoplastic elastomers (P-TPEs) derived from α-diimine nickel / palladium catalysts have seen rapid development. This method relies solely on ethylene or propylene as monomer feedstock, and by finely adjusting the chain extension, P-TPE products with semi-crystalline or amorphous structures can be easily obtained. Furthermore, in the nickel / palladium catalytic system, introducing sterically hindered ligands can effectively suppress chain transfer reactions, enabling the formation of ultra-high molecular weight polyolefin thermoplastic elastomers and significantly improving their mechanical properties. However, like other ultra-high molecular weight polymers, ultra-high molecular weight polyolefin thermoplastic elastomers also suffer from poor processability due to their branched, highly entangled structure in the molten state. Introducing low molecular weight components to prepare bimodal ultra-high molecular weight polymers can improve entanglement kinetics and melt rheology, enhancing their processability while retaining the inherent mechanical properties and durability of the high molecular weight fraction.

[0004] However, to date, there are still very few reports on bimodal ultra-high molecular weight polyolefin thermoplastic elastomers, and there is no efficient preparation of bimodal ultra-high molecular weight polyethylene thermoplastic elastomers that combine high mechanical properties and excellent processability. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a class of closed-ring semi-sandwich type containing an axial benzene ring η 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalyst, its preparation method and preparation method of ultra-high molecular weight bimodal polyethylene. The catalyst provided in this application can prepare ultra-high molecular weight bimodal polyethylene thermoplastic elastomer with both high mechanical properties and excellent processability.

[0006] This application provides a closed-loop semi-sandwich type containing an axial benzene ring η as shown in formula (II). 6 - Large steric hindrance of coordination α-Diimine cationic nickel catalyst: Formula (II); In equation (II), R1 has the structure of equation (a): Equation (a); R2 and R3 are derived independently from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6. 20 One of the aromatic groups; R7 and R8 are independently selected from H, substituted or unsubstituted C1~C. 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; The substituents are independently selected from halogens or C1-C6 alkyl groups.

[0007] In some specific implementations, in formula (II), R2 is H; R3 is selected from H or C1~C6 alkyl groups; R4, R5 and R6 are H; R7 and R8 are C1~C6 alkyl groups.

[0008] In some specific implementations, in formula (II), R3 is selected from H, methyl or tert-butyl; R7 and R8 are methyl.

[0009] In some specific implementations, the closed-loop semi-sandwich type containing an axial benzene ring η 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalysts have structures of formulas (II-1) to (II-9): (II-1); (II-2); (II-3); (II-4); (II-5); (II-6); (II-7); (II-8); (II-9).

[0010] This application also provides the closed-loop semi-sandwich type containing axial benzene ring η described in the above-mentioned technical solution.6 - Large steric hindrance of coordination α The preparation method of the diimine cationic nickel catalyst includes the following steps: The ligand shown in formula (I), nickel acetylacetone, and [CPh3][B(C6F5)4] react to yield the complex shown in formula (II): Formula (I); Formula (II); In equation (I) or equation (II), R1 has the structure of equation (a): Equation (a); R2 and R3 are derived independently from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6. 20 One of the aromatic groups; R7 and R8 are independently selected from H, substituted or unsubstituted C1~C. 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; The substituents are independently selected from halogens or C1-C6 alkyl groups.

[0011] In some specific implementations, the reaction temperature is room temperature and the time is 10h~20h.

[0012] This application provides a catalyst composition comprising the closed-ring semi-sandwich type containing an axial benzene ring η as described in the above-described technical solution. 6 -A sterically hindered α-diimine cationic nickel catalyst with coordination or the preparation method described above, yielding a closed-ring semi-sandwich type containing an axially oriented benzene ring η. 6 -Coordinated, sterically hindered α-diimine cationic nickel catalysts and co-catalysts.

[0013] In some specific implementations, the cocatalyst includes one or more of methylaluminoxane, modified methylaluminoxane, alkylaluminum, and alkylaluminum chloride.

[0014] In some specific implementations, the closed-loop semi-sandwich type containing an axial benzene ring η 6 - The molar ratio of nickel to co-catalyst in a well-coordinated, sterically hindered α-diimine cationic nickel catalyst is 1:20~4000.

[0015] This application also provides a method for preparing an ultra-high molecular weight bimodal polyethylene thermoplastic elastomer, comprising the following steps: Ethylene undergoes polymerization under the action of a catalyst to obtain ultra-high molecular weight bimodal polyethylene thermoplastic elastomer; The catalyst described above is a closed-ring semi-sandwich type containing an axial benzene ring η. 6 -A sterically hindered α-diimine cationic nickel catalyst with coordination or a closed-ring semi-sandwich sterically hindered α-diimine cationic nickel catalyst prepared by the preparation method described in the above technical solution or the catalyst composition described in the above technical solution.

[0016] This application provides a class of closed-ring semi-sandwich type containing an axial benzene ring η. 6 -Coordinated, sterically hindered α-diimine cationic nickel catalysts, their preparation methods and applications, through a closed semi-sandwich ring structure and axially oriented benzene ring η 6 - Coordination forms the electronic effect and steric hindrance regulation of the axial benzene ring on the cationic nickel metal center. Within a single active center, the catalyst simultaneously forms two kinetically different active centers with high and low steric hindrance, enabling one-step catalytic polymerization of ethylene in a single reactor to directly obtain bimodal ultra-high molecular weight polyethylene thermoplastic elastomer.

[0017] Experiments show that, under mild conditions, the catalyst prepared in this application exhibits high activity (~1 g·mo ¹· ¹), and the molecular weight distribution of the product can be controlled (PDI = 5.0~20.0). The resulting bimodal polyethylene combines the high strength and high elasticity of the high molecular weight component with the good processing flowability of the low molecular weight component, and has a moderate degree of branching (22.0~131.6 / 1000C). While achieving excellent comprehensive performance, it significantly improves the processability and has outstanding industrial application potential and market prospects. Attached Figure Description

[0018] Figure 1 The catalyst meso-(S,R)-Ni1 prepared in Example 4 of this application acac A schematic diagram of a single crystal structure; Figure 2 The catalyst meso-(S,R)-Ni2 prepared in Example 5 of this application acac A schematic diagram of a single crystal structure; Figure 3 The catalyst meso-(S,R)-Ni3 prepared in Example 6 of this application acac A schematic diagram of a single crystal structure; Figure 4The catalyst rac-(S,SR,R)-Ni3 prepared in Example 7 of this application acac (R,R)-Ni3 acac Schematic diagram of the single-crystal structure of the isomer; Figure 5 This is a GPC diagram (global view) of the polyethylene prepared in Example 11. Figure 6 This is a GPC curve of the polyethylene prepared in Example 11; Figure 7 This is a peak separation curve of the polyethylene prepared in Example 11; Figure 8 This is a GPC diagram (global view) of the polyethylene prepared in Example 17. Figure 9 This is the GPC curve of the polyethylene prepared in Example 17; Figure 10 This is a peak separation curve of the polyethylene prepared in Example 17; Figure 11 GPC curves of polyethylene prepared at different temperatures using the catalyst prepared in Example 6; Figure 12 GPC curves of polyethylene prepared at different temperatures using the catalyst prepared in Example 7; Figure 13 Tensile property curves of polyethylene prepared in Examples 8 and 11; Figure 14 Cyclic tensile properties curve of polyethylene prepared in Example 11; Figure 15 Composite viscosity curves of polyethylene prepared in Examples 8 and 11; Figure 16 Modulus curves of polyethylene prepared in Examples 8 and 11; Figure 17 Tensile property curves of polyethylene prepared in Examples 14 and 17; Figure 18 Cyclic tensile properties curve of polyethylene prepared in Example 17; Figure 19 Composite viscosity curves of polyethylene prepared in Examples 14 and 17; Figure 20 Modulus curves for polyethylene prepared in Examples 14 and 17. Detailed Implementation

[0019] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0020] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0021] It should be understood that the order of steps or the sequence of actions is not important as long as this application remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0022] This application provides a closed-loop semi-sandwich type containing an axial benzene ring η, as shown in formula (II). 6 - Large steric hindrance of coordination α -Diimine cationic nickel catalyst: Equation (II).

[0023] The closed-loop semi-sandwich type containing an axial benzene ring η provided in this application 6 - Large steric hindrance of coordination α -Diimide cationic nickel catalysts utilize a closed semi-sandwich cyclic structure with an axially oriented benzene ring η 6 - Coordination forms the electronic effect and steric hindrance regulation of the axial benzene ring on the cationic nickel metal center. Within a single active center, the catalyst simultaneously forms two kinetically different active centers with high and low steric hindrance, enabling one-step catalytic polymerization of ethylene in a single reactor to directly obtain bimodal ultra-high molecular weight polyethylene thermoplastic elastomer.

[0024] In equation (II), R1 has the structure of equation (a): Formula (a).

[0025] In equation (II), R2 and R3 are independently derived from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups. Specifically, R2 is preferably H, substituted or unsubstituted C1~C. 10 The alkyl group is more preferably H, or a substituted or unsubstituted C1-C6 alkyl group, with H being the most preferred. R3 is preferably H, or a substituted or unsubstituted C1-C6 alkyl group. 10The alkyl group is more preferably H, a substituted or unsubstituted C1-C6 alkyl group, and most preferably H, methyl or tert-butyl. The substituent is independently selected from halogens or C1-C6 alkyl groups, preferably fluorine, chlorine, bromine, methyl, ethyl, propyl, butyl or pentyl.

[0026] In formula (II), R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6 alkyl. 20 R4 is one of the aromatic groups. Specifically, R4 is preferably H, a substituted or unsubstituted C1-C6 alkyl group, more preferably H. R5 is preferably H, a substituted or unsubstituted C1-C6 alkyl group, more preferably H. R6 is preferably H, a substituted or unsubstituted C1-C6 alkyl group, more preferably H. The substituents are independently selected from halogens or C1-C6 alkyl groups, preferably fluorine, chlorine, bromine, methyl, ethyl, propyl, butyl, or pentyl.

[0027] In formula (II), R7 and R8 are independently selected from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups. Specifically, R7 is preferably H, substituted or unsubstituted C1~C. 10 The alkyl group is preferably H, a substituted or unsubstituted C1-C6 alkyl group, and most preferably methyl. The substituent is independently selected from halogens or C1-C6 alkyl groups, preferably fluorine, chlorine, bromine, methyl, ethyl, propyl, butyl, or pentyl.

[0028] In some specific implementations, the closed-loop semi-sandwich type containing an axial benzene ring η 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalysts have structures of formulas (II-1) to (II-9): (II-1); (II-2); (II-3); (II-4); (II-5); (II-6); (II-7); (II-8); (II-9).

[0029] This application also provides the closed-loop semi-sandwich type containing axial benzene ring η described in the above-mentioned technical solution. 6 - Large steric hindrance of coordination α The preparation method of the diimine cationic nickel catalyst includes the following steps: The ligand shown in formula (I), nickel acetylacetone, and [CPh3][B(C6F5)4] react to yield the complex shown in formula (II): Formula (I); Formula (II); In equation (I) or equation (II), R1 has the structure of equation (a): Equation (a); R2 and R3 are derived independently from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6. 20 One of the aromatic groups; R7 and R8 are independently selected from H, substituted or unsubstituted C1~C. 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; The substituents are independently selected from halogens or C1-C6 alkyl groups.

[0030] This application uses the ligand shown in formula (I), nickel acetylacetone, and triphenyltetra(pentafluorophenyl)borate ([CPh3][B(C6F5)4]) as raw materials to prepare the complex shown in formula (II), wherein the selection of R1 to R8 is as described above, and will not be repeated here.

[0031] In this application, the ligand represented by formula (I) can be prepared according to the following method: The semi-closed-ring diamine shown in formula (III) and the ketene dione shown in formula (IV) react under the action of a catalyst to obtain the ligand shown in formula (I).

[0032] Formula (III); Formula (IV); This application does not impose any particular restriction on the source of the semi-closed cyclic diamine shown in formula (III), which can be purchased from the market or prepared according to the method disclosed in Macromolecules 2025, 58, 1888-1897. This application does not impose any particular restriction on the source of the ketene dione shown in formula (IV), which can be purchased from the market.

[0033] This application involves reacting a semi-closed-ring diamine of formula (III), a ketene of formula (IV), a catalyst, and a solvent to obtain the ligand of formula (I). In some specific implementations, the catalyst includes, but is not limited to, p-benzenesulfonic acid monohydrate, formic acid, acetic acid, or titanium tetrachloride, and may be one or more of these, preferably p-benzenesulfonic acid monohydrate. In some specific implementations, the solvent includes, but is not limited to, toluene, methanol, ethanol, xylene, or o-dichlorobenzene, and may be one or more of these, preferably toluene. In some specific implementations, the molar ratio of the semi-closed-ring diamine of formula (III) to the ketene of formula (IV) is 0.8~1.2:1, preferably 1:1. In some specific implementations, the molar ratio of the catalyst to the ketene of formula (IV) is 0.05~1, preferably 0.1~0.8:1, more preferably 0.3~0.7:1. In some specific implementations, the reaction temperature is a heating reflux reaction, and the time is 5h to 48h, preferably 6h to 10h.

[0034] After the reaction is complete, the solvent is dried under vacuum, dissolved in dichloromethane, and washed with saturated sodium bicarbonate aqueous solution until neutral. The resulting dichloromethane phase is dried with anhydrous magnesium sulfate and then purified by column chromatography to obtain the ligand shown in formula (I). In some specific implementations, the eluent for column chromatography is a mixture of petroleum ether and ethyl acetate, wherein the volume ratio of petroleum ether to ethyl acetate is 10~100:1, preferably 20~80:1, and more preferably 30~60:1.

[0035] After obtaining the ligand shown in formula (I), it is reacted with nickel acetylacetonate, [CPh3][B(C6F5)4], and a solvent to obtain the complex shown in formula (II). In some specific implementations, the solvent includes, but is not limited to, dichloromethane, chloroform, or toluene, preferably dichloromethane. In some specific implementations, the molar ratio of the ligand shown in formula (I), nickel acetylacetonate, and [CPh3][B(C6F5)4] is 0.8~1.2:0.8~1.2:0.8~1.2, preferably 1:1:1. In some specific implementations, the reaction temperature is room temperature, for example, 10℃~60℃, preferably 20℃~50℃, and the reaction time is 10h~20h, preferably 12h~15h. In some specific implementations, the reaction is carried out under stirring.

[0036] After the reaction was complete, the reaction product was concentrated, and hexane was added to precipitate it. The precipitate was washed with hexane to obtain the complex shown in formula (II).

[0037] The closed-loop semi-sandwich type containing an axial benzene ring η provided in this application 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalysts can catalyze the polymerization of ethylene in a single reactor in one step to directly obtain bimodal ultra-high molecular weight polyethylene thermoplastic elastomers.

[0038] This application also provides a catalyst composition comprising: the closed-ring semi-sandwich type containing an axial benzene ring η as described in the above technical solution. 6 - Large steric hindrance of coordination α - The closed-ring semi-sandwich type containing axial benzene ring η prepared by the diimine cationic nickel catalyst or the preparation method described above. 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalyst and co-catalyst.

[0039] The catalyst composition provided in this application includes the closed-ring semi-sandwich type containing an axial benzene ring η as described in the above-mentioned technical solution. 6 - Large steric hindrance of coordination α -Diimine cationic nickel catalysts, which will not be described in detail here.

[0040] The catalyst composition provided in this application includes a co-catalyst, which includes, but is not limited to, methylaluminoxane, modified methylaluminoxane, alkylaluminum, alkylaluminum chloride, etc., and can be one or more of them, preferably alkylaluminum chloride, such as diethylaluminum chloride.

[0041] In some specific implementations, the closed-loop semi-sandwich type containing an axial benzene ring η 6 - Large steric hindrance of coordinationα The molar ratio of nickel to co-catalyst in the diimine cationic nickel catalyst is 1:20~4000, preferably 1:100~3000, and more preferably 1:500~1000.

[0042] This application also provides a method for preparing an ultra-high molecular weight bimodal polyethylene thermoplastic elastomer, comprising the following steps: Ethylene undergoes polymerization under the action of a catalyst to obtain ultra-high molecular weight bimodal polyethylene thermoplastic elastomer; The catalyst comprises the closed-ring semi-sandwich type containing an axial benzene ring η as described in the above technical solution. 6 - Large steric hindrance of coordination α - The closed-ring semi-sandwich type containing axial benzene ring η prepared by the diimine cationic nickel catalyst or the preparation method described above. 6 - Large steric hindrance of coordination α - Diimine cationic nickel catalyst or the catalyst composition described in the above technical solution.

[0043] This application uses the closed-loop semi-sandwich type containing axial benzene ring η described in the above technical solution. 6 - Large steric hindrance of coordination α A diimine cationic nickel catalyst or the catalyst composition described in the above-described technical solutions is used as a catalyst to catalyze the polymerization reaction of ethylene. Specifically, this application first preheats and evacuates the polymerization reactor, replaces it with ethylene, cools the polymerization reactor to the reaction temperature, adds the catalyst and solvent, and then introduces ethylene to carry out the polymerization reaction. In some specific implementations, the reaction temperature of the polymerization reaction is -10℃ to 100℃, preferably -5℃ to 80℃. In some specific implementations, the pressure of the polymerization reaction is 0.1 atm to 30 atm, preferably 1 atm to 20 atm.

[0044] After the reaction was terminated, the obtained polymer was precipitated with ethanol, filtered, and washed to obtain ultra-high molecular weight bimodal polyethylene thermoplastic elastomer.

[0045] Experiments show that, under mild conditions, the catalyst prepared in this application exhibits high activity (~1 g·mo ¹· ¹), and can control the molecular weight distribution of the product (PDI = 5.0~20.0). The resulting bimodal polyethylene has the high strength and high elasticity of the high molecular weight component and the good processing fluidity of the low molecular weight component, and has a moderate degree of branching (22.0~131.6 / 1000C). While achieving excellent comprehensive performance, it significantly improves the processability and has outstanding industrial application potential and market prospects.

[0046] This application provides a class of closed-ring semi-sandwich type containing an axial benzene ring η. 6 -Coordinated, sterically hindered α-diimine cationic nickel catalysts, their preparation methods and applications, through a closed semi-sandwich ring structure and axially oriented benzene ring η 6 - Coordination forms the electronic effect and steric hindrance regulation of the axial benzene ring on the cationic nickel metal center. Within a single active center, the catalyst simultaneously forms two kinetically different active centers with high and low steric hindrance, enabling one-step catalytic polymerization of ethylene in a single reactor to directly obtain bimodal ultra-high molecular weight polyethylene thermoplastic elastomer.

[0047] The present application is further illustrated below with reference to embodiments. The scope of protection of the present application is not limited to the following embodiments.

[0048] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0049] Unless otherwise specified, the reagents, materials, equipment, etc. used in the following examples are all commercially available.

[0050] General procedure: All operations involving air and moisture-sensitive compounds are performed in a dry and oxygen-free nitrogen atmosphere, using standard Schlenk techniques, or in a glove box.

[0051] The NMR spectra of the intermediates and ligands were recorded at room temperature using a Bruker 400 MHz instrument. The NMR spectra of the polymer were obtained at 120 °C using 1,1,2,2-tetrachloroethane-d 2 or o -dichlorobenzene-d 4 As a solvent.

[0052] FTIR spectra were recorded using a Bruker TENSOR 27 FTIR spectrometer.

[0053] X-ray diffraction data were collected on a Brook SMARTAPEX diffractometer using a CCD surface detector and graphite monochromatic Mo-ka (λ=0.71073Å) or Cu-ka radiation (λ=1.54178Å).

[0054] High-resolution mass spectrometry (HRMS) was obtained on a Waters XEVO G2 QTof mass spectrometer.

[0055] The molecular weight and molecular weight distribution (Mw / Mn) of the polymer were measured using an Agilent 1260 Infinity I HT high-temperature gel permeation chromatography system equipped with two PLgel 10 μm MIXED-B columns, with 1,2,4-trichlorobenzene as the mobile phase at 150 °C and a flow rate of 1.0 mL / min.

[0056] On a Netzsch DSc3500 Sirius instrument, at 10 °C·min -1 The melting point (Tm) of the polymer was obtained by differential scanning calorimetry (DSC) from 0°C to 200°C; the data were obtained from the second heating cycle.

[0057] The degree of branching of polyethylene was measured by proton nuclear magnetic resonance spectroscopy, and the unit was the number of branches per 1000 carbon atoms.

[0058] Bimodal polymer separation: The polymer sample was wrapped in a filter screen and fixed with iron wire. Sochter extraction was performed using n-hexane as solvent at a heating temperature of 10°C for 6 hours. The polymer residue remaining in the filter screen was component one. Subsequently, the extraction solvent was dried to separate component two. All fractions were dried under vacuum at 50°C for 24 hours and then weighed and tested.

[0059] Preparation of tensile curve plates and rheological test discs: The polymer was precipitated from the polymerization reactor into an ethanol solution containing 10% hydrochloric acid, then filtered and rinsed twice with ethanol. After vacuum drying at 50°C for 24 h, the purified polymer was granulated (particle size < 5 mm). The sample was compressed and molded on a plate vulcanizing machine using a 30×40×0.9 mm stainless steel mold, according to the following thermal procedure: (1) preheating at 185°C for 5 min without pressure; (2) maintaining a pressure of 10 MPa for 5 min; (3) rapidly cooling to 30°C under a pressure of 1 MPa for 3 min. Tensile test samples were cut from the molded sheet with a cutter size of 12.5 mm gauge length × 2 mm width and a disc mold size of 25 mm.

[0060] Tensile strength test method: The stress-strain test was carried out at room temperature using the UTM2502 standard test method and a universal testing machine at a rate of 50 mm / min.

[0061] Test method for composite viscosity and storage modulus: The measurement was carried out in oscillation mode using a rotational rheometer within a temperature range of 80℃ to 180℃, with a scanning rate of 3℃ / min, an angular frequency of 1.0Hz, and a strain amplitude of 1%.

[0062] Example 1

[0063] A semi-closed-ring diamine 1 was prepared according to the method disclosed in Macromolecules 2025, 58, 1888-1897. NH2 ; 1.05g of semi-closed-ring diamine 1 NH2 0.50g of ketene dione C=O0.04 g of p-toluenesulfonic acid monohydrate (PTSA) was added to a 250 mL round-bottom flask, followed by 200 mL of purified toluene to dissolve it completely. The mixture was then assembled with a water separator and heated under reflux for 6 h. After the reaction was complete, the solvent was removed and the mixture was dissolved in dichloromethane and washed with saturated sodium bicarbonate aqueous solution until neutral. The dichloromethane phase was dried over anhydrous magnesium sulfate and then dried under reflux to obtain a bright yellow viscous liquid. The liquid was purified by column chromatography (ethyl acetate / petroleum ether = 1:40) to remove the solvent and obtain 0.12 g of bright yellow crystals, denoted as ligand L1, which is a mixture of meso-(S,R) and rac-(S,SR,R) isomers, with a yield of 7.6%.

[0064] The reaction route is as follows:

[0065] The ligand L1 was subjected to NMR analysis, and the data are as follows: meso-(S,R) isomers: 1 H NMR (400 MHz, CDCl3), 7.55 (m, 2H, ArH), 7.44 (m, 2H, ArH), 6.47 (s, 2H, ArH), 5.30 (s, 1H, ArH), 5.03 (s, 2H, CH), 4.59 (s, 2H, CH), 2.23 (s, 6H, Ar-CH3), 1.85 (s, 6H, Ar-CH3), other peaks overlap.

[0066] rac-(S,SR,R) isomers: 1 H NMR (400 MHz, CDCl3), 6.80 (m, 1H, ArH), 6.40 (s, 1H, ArH), 5.61 (s, 1H, CH), 5.50 (s, 1H, ArH), 5.04 (s, 1H, CH), 4.89 (s, 1H, CH), 4.21 (s, 1H, CH), 2.35 (s, 3H, Ar-CH3), 2.23 (s, 3H, Ar-CH3), 1.88 (s, 3H, Ar-CH3), 2.35 (s, 1.85, 3H, Ar-CH3), other peaks overlap.

[0067] 13C NMR (101 MHz, CDCl3 ) δ 155.10, 154.51, 143.68, 140.95, 140.58, 136.84, 132.94, 130.74, 130.57, 128.63, 128.37, 128.29, 128.11, 127.48, 127.26, 127.21, 12 6.91, 126.75, 126.44, 125.40, 124.59, 124.32, 124.11, 123.19, 56.14, 54.73, 52.38, 50.57, 28.67, 20.03, 19.67, 17.81, 17.04, 16.95.

[0068] Infrared analysis of the ligand L1 was performed, and the data are as follows: FT-IR (cm -1 ): 3022(w), 2963(w), 2923(w), 2848(w), 1673(w), 1640(w, v(C=N)), 1598(w), 1491(w), 1376(w), 1260(w), 1212(w), 1193(w), 1094(w), 1022(w), 858(w), 802(w), 756(w), 716(w), 689(m), 638(w), 577(w), 515(w).

[0069] Mass spectrometry analysis of the ligand L1 was performed, and the data are as follows: ESI-MS of L1, calcd. for C 52 H 42 N2: 694.3348, found 695.3404 [M + H] + .

[0070] Example 2

[0071] The difference from Example 1 is that a semi-closed-ring diamine 1 is used. NH2 Replace with a methyl-containing semi-closed-ring diamine 2 NH2 (Prepared according to the method disclosed in Macromolecules 2025, 58, 1888-1897), with other steps and parameters being the same, to obtain a mixture of ligands L2 including meso-(S,R) and rac-(S,SR,R) isomers in a yield of 5.2% (134.6 mg, 0.19 mmol).

[0072] The reaction route is as follows:

[0073] The ligand L2 was subjected to NMR analysis, and the data are as follows: meso-(S,R) isomers: 1 H NMR (400 MHz, CDCl3) 7.48 (m, 2H, ArH), 7.38 (m, 2H, ArH), 6.90 (s, 5H, ArH), 6.80 (s, 2H, ArH), 6.44 (s, 2H, ArH), 5.07 (s, 1H, ArH), 5.01 (s, 2H, CH), 4.53 (s, 2H, CH), 2.18 (s, 9H, Ar-CH3), 1.82 (s, 6H, Ar-CH3).

[0074] rac-(S,SR,R) isomers: 1 H NMR 702 (m, 2H, ArH), 6.86 (m, 1H, ArH), 6.73 (m, 2H, ArH), 6.37 (s, 1H, ArH), 5.50 (s, 1H, CH), 5.26 (s, 1H, ArH), 4.87 (s, 1H, CH), 4.15 (s, 1H, CH), 2.30 (s, 3H, Ar-CH3), 2.15 (s, 6H, Ar-CH3), 1.87 (s, 3H, Ar-CH3), 1.85 (s, 3H, Ar-CH3).

[0075] 13 C NMR (101 MHz, CDCl3 ) δ 155.23, 155.02, 154.30, 144.05, 143.75, 142.97, 140.75, 140.37, 137.06, 136.88, 131 .33, 130.77, 130.65, 128.65, 128.61, 128.22, 128.03, 127.42, 127.24, 126.86, 126.74, 126.35, 126.10, 125.32, 125.18, 125.13, 124.89, 124.59, 124.35, 122.99, 56.33, 54.61, 53.35, 50.64, 50.51, 50.36, 21.46, 20.92, 20.13, 20.04, 19.67, 17.91, 17.09, 16.97.

[0076] Infrared analysis of the ligand L2 was performed, and the data are as follows: 3060(w), 3019(w), 2963(w), 2921(w), 2858(w), 1692(w), 1664(w, v(C=N)), 1491(w), 1460(w), 1260(w), 1229(w), 1206(w), 1139(w), 1090(w), 1073 (w), 1030(w), 914(w), 861(w), 794(w), 756(w), 700(m), 632(w), 584(w), 514(w).

[0077] Mass spectrometry analysis of the ligand L2 was performed, and the data are as follows: calcd. for C 53 H 44 N2: 708.3504, found 709.3579 [M + H] + .

[0078] Example 3

[0079] The difference from Example 1 is that a semi-closed-ring diamine 1 is used. NH2 Replace with a methyl-containing semi-closed-ring diamine 3 NH2 (Prepared according to the method disclosed in Macromolecules 2025, 58, 1888-1897), with other steps and parameters being the same, yielding meso-(S,R) isomers (denoted as ligand meso-(S,R)-L3) and rac-(S,SR,R) isomers (denoted as ligand rac-(S,SR,R) isomer-L3), with an overall yield of 5.2%.

[0080] The meso-(S,R) and rac-(S,SR,R) isomers were separated by column chromatography at a petroleum ether:ethyl acetate volume ratio of 40:1 to obtain the ligand meso-(S,R)-L3 and the ligand rac-(S,SR,R) isomer-L3, respectively.

[0081] The NMR analysis of the ligand meso-(S,R)-L3 was performed, and the data are as follows: meso-(S,R)-L3 isomer: 1H NMR (400 MHz, CDCl3) δ 7.50 (s, 2H, ArH), 7.40-7.26 (m, 15H, ArH), 7.20 (t, 2H, ArH), 6.98 (s, 2H, ArH), 6.93 (s, 2H, ArH), 6.48 (s, 2H, ArH), 5.10 (s, 1H, ArH), 5.01 (s, 2H, CH), 4.56 (s, 2H, CH), 2.23 (s, 6H, Ar-CH3), 1.80 (s, 6H, Ar-CH3), 1.17 (s, 9H, tBu).

[0082] meso-(S,R)-L3 isomer: 13 C NMR (101 MHz, CDCl3) δ 155.21, 151.15, 144.49, 141.78, 140.84, 137.72, 131.80, 131.59, 131.36, 129.52, 128.77, 128.22, 127. 98, 127.55, 127.25, 126.09, 125.37, 125.12, 123.67, 121.56, 55.60, 51.41, 34.50, 31.35, 20.89, 17.90.

[0083] Infrared analysis of the ligand meso-(S,R)-L3 was performed, and the data are as follows: FT-IR (cm -1 ): 3064(w), 3022(w), 2967(w), 2919(w), 2856(w), 1685(w), 1664(w, v (C=N)), 1598(w), 1514(s), 1492(w), 1462(w), 1266(w), 1245(s), 1143(s), 1079(w), 1034(w), 862(w), 841(w), 808(w), 757(w), 693(m).

[0084] Mass spectrometry analysis of the ligand meso-(S,R)-L3 was performed, and the data are as follows: ESI-MS calcd for C 56 H 50 N2: 750.3974, found 751.4053 [M + H] + .

[0085] NMR analysis of the ligand rac-(S,SR,R) isomer-L3 was performed, and the data are as follows: rac-(S,SR,R)-L3 isomer: 1 H NMR (400 MHz, CDCl3) δ 7.41 (d, 1H, ArH), 7.32-7.11 (m, 12H, ArH), 7.06 (m, 2H, ArH), 6.96-6.91 (m, 7H, ArH), 6.78 (t, 1H, ArH), 6.43 (s, 1H, ArH), 5.53 (s, 1H, ArH), 5.31 (s, 1H, ArH), 5.05 (s, 1H, CH), 4.94 (s, 1H, CH), 4.22 (s, 1H, CH), 2.36 (s, 3H, Ar-CH3), 2.24 (s, 3H, Ar-CH3), 1.92 (s, 3H, Ar-CH3), 1.87 (s, 3H, Ar-CH3), 1.21 (s, 9H, tBu).

[0086] rac-(S,SR,R)-L3 isomer: 13 C NMR (101 MHz, CDCl3) δ 155.75, 154.72, 149.72, 145.03, 144.78, 143.75, 142.06, 139.96, 139.63, 138.78, 137.92, 13 7.55, 136.98, 132.82, 132.27, 132.14, 131.32, 131.22, 130.57, 129.78, 129.49, 129.03, 128.6 5, 127.99, 127.65, 127.27, 127.06, 127.04, 126.96, 126.88, 125.98, 125.76, 125.30, 124.95, 124.54, 123.85, 122.00, 57.85, 54.37, 51.38, 51.19, 34.39, 31.42, 20.97, 20.53, 18.80, 17.80.

[0087] Infrared analysis was performed on the ligand rac-(S,SR,R) isomer-L3, and the data are as follows: FT-IR (cm -1): 3058 (w), 3020 (w), 2923 (m), 2861 (m), 2964 (m), 1737 (w), 1693 (m), 1659 (m, v(C=N)), 1598 (m), 1496 (m), 1466 (m), 1446 (m), 1363 (w), 1257 (s), 1236 (m), 1098 (s), 1021 (s), 858 (m), 800 (s), 758 (m), 702 (m).

[0088] Mass spectrometry analysis of the ligand rac-(S,SR,R) isomer-L3 was performed, and the data are as follows: ESI-MS calcd for C 56 H 50 N2: 750.3974, found 751.4040 [M + H] + .

[0089] Example 4

[0090] In a nitrogen-filled glove box, a 50 mL flask containing 40 mL of dry dichloromethane, ligand L1 (347 mg, 0.5 mmol) prepared in Example 1, Ni(acac)2 (131.4 mg, 0.5 mmol), and [CPh3][B(C6F5)4] (471.42 mg, 0.5 mmol) was placed inside. The mixture was stirred at room temperature for 12 h to obtain a deep red solution. The deep red solution was concentrated to 8 mL under vacuum, and then n-hexane was added to precipitate the solution. The precipitate was collected by filtration and washed three times with n-hexane (15 mL each time, for a total of 3 times) to obtain a deep red solid, which was identified as catalyst Ni1. acac It is a mixture of meso-(S,R) (Formula II-1) and rac-(S,SR,R) isomers (Formula II-2 and II-3). Yield: 90% (0.383 g, 0.45 mmol).

[0091] The reaction route is as follows:

[0092] See Figure 1 , Figure 1 The catalyst meso-(S,R)-Ni1 prepared in Example 4 of this application acac A schematic diagram of the single crystal structure.

[0093] For the catalyst Ni1 acac The NMR analysis was performed, and the data are as follows: meso-(S,R) isomers:1 H NMR (400 MHz, CDCl3) δ 7.62 (s, 2H, ArH), 7.52 (s, 2H, ArH), 7.43-7.33 (15H, ArH), 7.23 (s, 6H, ArH), 7.08 (s, 4H, ArH), 6.87 (s, 3H, ArH), 6.48 (s, 2H, ArH), 5.80 (s, 1H , ArH), 5.26 (s, 1H, CH), 4.98 (s, 2H, CH), 4.58 (s, 2H, CH), 2.09 (s, 6H, Ar-CH3), 2.06 (s, 6H, Ar-CH3), 1.30 (s, 6H, Ar-CH 3 Other peaks overlap.

[0094] rac-(S,SR,R) isomers: 1 H NMR (400 MHz, CDCl3) 7.52 (s, 2H, ArH), 7.19 (s, 6H, ArH), 7.02-6.98 (d, 4H, ArH), 6.87 (s, 3H, ArH), 6.61- 6.56(s, 1H, ArH), 6.41(s, 1H, ArH), 5.50(s, 1H, ArH), 5.26(s, 1H, CH), 5.17(s, 2H, CH), 4.52 (s, 1H, CH), 4.41 (s, 1H, CH), 2.28-2.22 (s, 3H, Ar-CH3), 2.16-2.1 4(s, 3H, Ar-CH3), 2.09 (s, 3H, Ar-CH3), 2.06 (s, 3H, Ar-CH3), 1.30 (s, 6H, Ar-CH 3 Other peaks overlap.

[0095] 13 C NMR (101 MHz, CDCl3) δ 186.23, 171.37, 141.20, 138.68, 138.59, 136.24, 135.43, 135.09, 131.48, 130.65, 130.56, 129. 43, 129.32, 129.11, 128.83, 128.45, 127.61, 126.59, 126.15, 55.00, 50.25, 23.68, 21.24, 18.36.

[0096] For the catalyst Ni1 acac Infrared analysis was performed, and the data is as follows: FT-IR (cm -1): 3094(w), 3064(w), 3031(w), 2959(w), 2926(w), 2868(w), 1705(w), 1644(w), 1582(m, v(C=N)), 1518(m), 1464(s), 1375(m), 1273(w), 1273(w), 1086(m), 1029(w), 982(m) , 772(w), 760(w), 701(w), 685(w), 661(w), 600(w), 573(w), 517(w), 465(w), 430(w).

[0097] For the catalyst Ni1 acac Mass spectrometry analysis was performed, and the data are as follows: ESI-MS of Ni1 acac ,calcd. for C 57 H 49 N2NiO2: 831.3148, found 832.3206 [M+H] + .

[0098] Example 5

[0099] The ligand L2 (365 mg, 0.5 mmol), Ni(acac)2 (131.4 mg, 0.5 mmol), and [CPh3][B(C6F5)4] (471.42 mg, 0.5 mmol) prepared in Example 2 were stirred at room temperature for 12 h to obtain a deep red solution. The deep red solution was concentrated to 8 mL under vacuum, and then n-hexane was added to precipitate the solution. The precipitate was collected by filtration and washed three times with n-hexane (15 mL each time, for a total of 3 times) to obtain a deep red solid, which was counted as catalyst Ni2. acac It is a mixture of meso-(S,R) (Formula II-4) and rac-(S,SR,R) (Formula II-5 and Formula II-6) isomers. Yield: 88% (0.38 g, 0.44 mmol).

[0100] The reaction route is as follows:

[0101] See Figure 2 , Figure 2 The catalyst meso-(S,R)-Ni2 prepared in Example 5 of this application acac A schematic diagram of the single crystal structure.

[0102] Regarding the catalyst Ni2 acac The NMR analysis was performed, and the data are as follows: meso-(S,R) isomers:1 H NMR (400 MHz, CDCl3) δ 7.61 (s, 2H, ArH), 7.52 (s, 2H, ArH), 7.34 (s, 20H, ArH), 7.26 (s, 10H, ArH), 7. 10(s, 6H, ArH), 7.00(s, 6H, ArH), 6.87(s, 4H, ArH), 6.70(s, 3H, ArH), 6.49-6. 42(s, 2H, ArH), 5.63(s, 1H, ArH), 5.27(s, 1H, CH), 4.96(s, 2H, ArH), 4.55(s, 2 H, ArH), 2.28 (s, 3H, Ar-CH3), 2.10 (s, 12H, Ar-CH3), 1.28 (s, 6H, CH3), and other peaks overlap.

[0103] rac-(S,SR,R) isomers: 1 H NMR (400 MHz, CDCl) 3 6.49-6.42 (s, 2H, ArH), 5.59 (s, 1H, ArH), 5.23 (s, 1H, CH), 5.11 (s, 1H, ArH), 5.07 (s, 1H, ArH), 4.79 (s, 1H, ArH), 4.15 (s, 1H, ArH), 2.02 (s, 12H, Ar-CH3), other peaks overlap.

[0104] 13 C NMR (101 MHz, CDCl3) δ 185.43, 170.27, 140.30, 137.73, 137.62, 135.29, 134.42, 134.01, 130.42, 129.62, 129.51, 128.73, 128.44, 128. 34, 128.06, 127.83, 127.54, 127.27, 126.91, 126.54, 126.25, 125.13, 53.84, 49.19, 22.64, 21.32, 20.23, 17.32.

[0105] Regarding the catalyst Ni2 acac Infrared analysis was performed, and the data is as follows: FT-IR (cm -1): 3062(w), 3026(w), 2960(w), 2924(w), 2865(w), 1642(w), 1602(m,v(C=N)), 1559(w), 1527(m), 1513(m), 1464(m), 1366(w), 1277(w), 1087(m), 1034(w), 1034(w), 1032(w), 979(m), 868(w), 773(w), 756(w), 701(w), 682(w), 661(w), 597(w), 487(w).

[0106] Regarding the catalyst Ni2 acac Mass spectrometry analysis was performed, and the data are as follows: ESI-MS of Ni2 acac ,calcd. for C 57 H 49 N2NiO2: 865.3382, found 866.3352[M+H] + .

[0107] Example 6

[0108] The ligand meso-(S,R)-L3 (0.380 mg, 0.5 mmol), Ni(acac)2 (131.4 mg, 0.5 mmol), and [CPh3][B(C6F5)4] (471.42 mg, 0.5 mmol) prepared in Example 3 were stirred at room temperature for 12 h to obtain a deep red solution. The deep red solution was concentrated to 8 mL under vacuum, and then n-hexane was added for precipitation. The precipitate was collected by filtration and washed three times with n-hexane (15 mL each time, for a total of 3 times) to obtain a deep red solid, which was counted as catalyst Ni3. acac It has a meso-(S,R) structure (Formula II-7). Yield: 85% (0.39 g, 0.43 mmol).

[0109] The reaction route is as follows:

[0110] See Figure 3 , Figure 3 The catalyst meso-(S,R)-Ni3 prepared in Example 6 of this application acac A schematic diagram of the single crystal structure.

[0111] The catalyst meso-(S,R)-Ni3 acac The NMR analysis was performed, and the data are as follows: meso-(S,R)-Ni3 acac : 1H NMR (400 MHz, CDCl3) δ 7.60 (s, 2H, ArH), 7.48 (s, 2H, ArH), 7.40-7.28 (t, 15H, ArH), 7.18 (s, 2H, ArH), 6.85 (s, 2H, ArH), 6.54 (s, 2H, ArH), 5.26 (s, H, ArH), 5.15 (s, 1H, C-CH), 4.98 (s, 2H, CH), 4.58 (s, 2H, CH), 2.10 (s, 6H, Ar-CH3), 2.01 (s, 6H, Ar-CH3), 1.27 (s, 6H, CH3), 0.97 (s, 9H, CH3).

[0112] meso-(S,R)-Ni3 acac : 13 C NMR (101 MHz, CDCl3) δ 185.80, 170.24, 153.37, 139.29, 137.99, 137.63, 135.19, 134.40, 134.36, 134.04, 130.15, 129.60, 129.48, 1 28.32, 128.22, 128.05, 127.52, 126.48, 125.57, 125.17, 124.10, 101.55, 54.12, 49.20, 30.04, 20.28, 17.29.

[0113] The catalyst meso-(S,R)-Ni3 acac Infrared analysis was performed, and the data is as follows: meso-(S,R)-Ni3 acac FT-IR (cm) -1 ): 3088(w), 3064(w), 3031(w), 2967(w), 2922(w), 2867(w), 1644(m), 1596(m, v(C=N)), 1558(m), 1514(m), 1464(m), 1364(w), 1274(w), 1088(m), 981(m), 865(w), 777(w), 756(w), 701(w), 683(w), 663(w), 599(w), 575(w), 490(w).

[0114] The catalyst meso-(S,R)-Ni3 acac Mass spectrometry analysis was performed, and the data are as follows: HRLC-MS calcd for C 61 H 57N2NiO2: 907.3774, found 908.3817 [M +H] + .

[0115] Example 7

[0116] The L3 ligand isomers rac-(S,SR,R)-L3 (0.380 mg, 0.5 mmol), Ni(acac)2 (131.4 mg, 0.5 mmol), and [CPh3][B(C6F5)4] (471.42 mg, 0.5 mmol) prepared in Example 3 were stirred at room temperature for 12 h to obtain a deep red solution. The deep red solution was concentrated to 8 mL under vacuum, and then n-hexane was added for precipitation. The precipitate was collected by filtration and washed three times with n-hexane (15 mL each time, for a total of 3 times) to obtain a deep red solid, which was identified as the catalyst rac-(S,SR,R)-Ni3. acac It has a rac-(S,SR,R) structure (Formula II-8 and II-9). Yield: 85% (0.39 g, 0.43 mmol).

[0117] The reaction route is as follows:

[0118] See Figure 4 , Figure 4 The catalyst rac-(S,SR,R)-Ni3 prepared in Example 7 of this application acac (R,R)-Ni3 acac A schematic diagram of the single-crystal structure of the isomer.

[0119] The catalyst rac-(S,SR,R)-Ni3 acac The NMR analysis was performed, and the data are as follows: rac-(S,SR,R)-Ni3 acac : 1H NMR (400 MHz, CDCl3 ) δ 7.54(s, 2H, ArH), 7.47(s, 2H, ArH), 7.44-7.39(t, 5H, ArH), 7.35-7.33(s, 5H, ArH), 7.26 (s, 6H, ArH), 7.17-7.13 (t, 2H, ArH), 7.09-7.07 (d, 2H, ArH), 6.96- 6.92(d, 3H, ArH), 6.77(s, 1H, ArH), 6.56(s, 1H, ArH), 6.45-6.43 (d, 1H, ArH), 5.71 (s, 1H, ArH), 5.64 (s, 1H, C-CH), 5.14 (s, 1H, CH), 4.87 (s, 2H, CH), 4.26 (s, 1H, CH), 2.3 6(s, 3H, CH3), 2.19 (s, 3H, CH3), 2.11 (s, 3H, CH3), 2.05 (s, 3H, CH3), 1.28 (s, 6H, CH3), 1.10 (s, 9H, CH3).

[0120] rac-(S,SR,R)-Ni3 acac : 13 C NMR (101 MHz, CDCl3) δ 185.42, 138.78, 138.36, 136.46, 135.20, 132.57, 132.47, 130.97, 129.83, 129.02, 128.44, 128.34, 127.82, 12 7.47, 126.20, 125.79, 125.68, 125.23, 101.37, 53.04, 48.97, 33.87, 30.14, 28.68, 22.58, 20.37, 19.88, 17.80.

[0121] The catalyst rac-(S,SR,R)-Ni3 acac Infrared analysis was performed, and the data is as follows: rac-(S,SR,R)-Ni3 acac FT-IR (cm) -1): 3067(w), 3027(w), 2959(w), 2923(w), 2869(w), 1644(w), 1601(m, v(C=N)), 1563(w), 1525(m), 1512(m), 1465(m), 1368(w), 1276(w), 1084(m), 1035(w), 982(m) , 866(w), 776(w), 759(w), 726(w), 700(w), 686(w), 662(w), 597(w), 489(w), 487(w), 433(w).

[0122] The catalyst rac-(S,SR,R)-Ni3 acac Mass spectrometry analysis was performed, and the data are as follows: rac-(S,SR,R)-Ni3 acac HRLC-MS calcd for C 61 H 57 N2NiO2: 907.3774, found908.3868 [M+H] + .

[0123] Example 8

[0124] First, the ethylene polymerization reactor was preheated to 120°C and evacuated under high vacuum for 2 hours. Then, it was purged three times with ethylene gas and cooled to 20°C under an ethylene gas flow. The reactor was then cooled to -5°C using a cooling cycle as the reaction temperature. 2 mL of a pre-prepared catalyst (meso-(S,R)-Ni3 prepared in Example 6) was added. acac ) dichloromethane solution (2 μ The product was stirred with purified toluene (AlEt2Cl) and the required amount of diethylaluminum chloride (AlEt2Cl) was added to make the Al / Ni molar ratio 600:1. Toluene was added to bring the total volume to 60 mL. Ethylene gas was introduced and a stable ethylene gas flow was maintained at a pressure of 10 atm. After the polymerization reaction was completed for 30 min, the reaction solution was poured into a small amount of 10% hydrochloric acid methanol solution to terminate the reaction. The obtained polymer was precipitated with ethanol, filtered and repeatedly washed, and then vacuum dried at 50 °C to constant weight.

[0125] Example 9

[0126] The other polymerization conditions are the same as in Example 8, except that the polymerization temperature is 5°C.

[0127] Example 10

[0128] The other polymerization conditions are the same as in Example 8, except that the polymerization temperature is 20°C.

[0129] Example 11

[0130] The other polymerization conditions are the same as in Example 8, except that the polymerization temperature is 40°C.

[0131] Example 12

[0132] The other polymerization conditions are the same as in Example 8, except that the polymerization temperature is 60°C.

[0133] Example 13

[0134] The other polymerization conditions are the same as in Example 8, except that the polymerization temperature is 80°C.

[0135] Example 14

[0136] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac .

[0137] Example 15

[0138] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization temperature is 5℃.

[0139] Example 16

[0140] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization temperature is 20℃.

[0141] Example 17

[0142] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization temperature is 40℃.

[0143] Example 18

[0144] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization temperature is 60℃.

[0145] Example 19

[0146] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization temperature is 80℃.

[0147] Example 20

[0148] The other polymerization conditions are the same as in Example 8, except that the aluminum ratio is 100:1.

[0149] Example 21

[0150] The other polymerization conditions are the same as in Example 8, except that the aluminum ratio is 200:1.

[0151] Example 22

[0152] The other polymerization conditions are the same as in Example 8, except that the aluminum ratio is 400:1.

[0153] Example 23

[0154] The other polymerization conditions are the same as in Example 8, except that the polymerization pressure is 1 atm.

[0155] Example 24

[0156] The other polymerization conditions are the same as in Example 8, except that the polymerization pressure is 2 atm.

[0157] Example 25

[0158] The other polymerization conditions are the same as in Example 8, except that the polymerization pressure is 6 atm.

[0159] Example 26

[0160] The other polymerization conditions are the same as in Example 8, except that the polymerization pressure is 20 atm.

[0161] Example 27

[0162] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization pressure is 1 atm.

[0163] Example 28

[0164] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization pressure is 2 atm.

[0165] Example 29

[0166] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization pressure is 6 atm.

[0167] Example 30

[0168] The other polymerization conditions are the same as in Example 8, the only difference being that the catalyst is replaced with rac-(S,SR,R)-Ni3 prepared in Example 7. acac The polymerization pressure is 20 atm.

[0169] The yield and activity of the polyethylene prepared in Examples 8-30 were calculated, and the results are shown in Table 1. Table 1 shows the conditions and performance parameters for preparing polyethylene in the examples of this application. The molecular weight, degree of branching, and glass transition temperature / melting point of the polyethylene prepared in Examples 8-30 were measured, and the results are shown in Table 1.

[0170] Table 1. Conditions and performance parameters for preparing polyethylene in the embodiments of this application.

[0171]

[0172] In Table 1, polymerization activity is expressed as 10 6 g mol -1 h -1 The unit is 30 min, and the polymerization time is 30 min.

[0173] Experimental Example 1

[0174] The molecular weight and molecular weight distribution of the polyethylene prepared in Example 11 were measured according to the method described above. The results are shown in [reference needed]. Figure 5 , Figure 6 and Figure 7 , Figure 5 This is a GPC diagram (global diagram) of the polyethylene prepared in Example 11. Figure 6 This is the GPC curve of the polyethylene prepared in Example 11. Figure 7 This is a peak separation curve of the polyethylene prepared in Example 11. Figure 7 As shown, the polyethylene prepared in Example 11 was separated according to the method described above, and the Mn of its low molecular weight component was 1.83 × 10⁻⁶. 4 Mw is 3.50×10 4 The PDI was 1.92; the Mn of the high molecular weight component was 52.28 × 10⁻⁶. 4 Mw is 171.85 × 10 4 The PDI is 3.29.

[0175] The molecular weight and molecular weight distribution of the polyethylene prepared in Example 17 were measured according to the method described above. The results are shown in [reference needed]. Figure 8 , Figure 9 and Figure 10 , Figure 8 This is a GPC diagram (global diagram) of the polyethylene prepared in Example 17. Figure 9 This is the GPC curve of the polyethylene prepared in Example 17. Figure 10 This is a peak separation curve of the polyethylene prepared in Example 17. Figure 10 As shown, the polyethylene prepared in Example 17 was separated according to the method described above, and the Mn of its low molecular weight component was 2.12 × 10⁻⁶. 4 Mw is 20.08×10 4 The PDI was 9.27; the Mn of the high molecular weight component was 88.84 × 10⁻⁶. 4 Mw is 176.61 × 10 4 The PDI is 2.03.

[0176] Experimental Example 2

[0177] GPC measurements were performed on the polyethylene prepared in Examples 8-13 according to the method described above, and the results are shown in [reference]. Figure 11 , Figure 11 The GPC curves of polyethylene prepared using the catalyst prepared in Example 6 at different temperatures are shown.

[0178] GPC measurements were performed on the polyethylene prepared in Examples 14-19 according to the method described above. The results are shown in [reference needed]. Figure 12 , Figure 12 The GPC curves of polyethylene prepared using the catalyst prepared in Example 7 at different temperatures are shown.

[0179] Depend on Figure 11 and Figure 12 It can be seen that as the temperature increases, the low molecular weight fraction gradually increases, and the bimodal trend becomes more obvious.

[0180] Experimental Example 3

[0181] The tensile properties, cyclic tensile properties, composite viscosity, and modulus of the polyethylene prepared in Examples 8 and 11 were tested according to the methods described above. The results are shown in [reference needed]. Figures 13-16 , Figure 13 The tensile property curves are for the polyethylene prepared in Examples 8 and 11. Figure 14 The cyclic tensile properties curve of the polyethylene prepared in Example 11 is shown. Figure 15 The composite viscosity curves of the polyethylene prepared in Examples 8 and 11 are shown. Figure 16 Modulus curves for polyethylene prepared in Examples 8 and 11. Figures 13-16 It can be seen that the tensile strength of the polyethylene prepared in Example 8 is 28.23 MPa, and the tensile strength of the polyethylene prepared in Example 11 is 28.05 MPa, indicating that the low molecular weight fraction does not affect the mechanical properties.

[0182] The tensile properties, cyclic tensile properties, composite viscosity, and modulus of the polyethylene prepared in Examples 14 and 17 were tested according to the methods described above. The results are shown in [reference needed]. Figures 17-20 , Figure 17 The tensile property curves are for the polyethylene prepared in Examples 14 and 17. Figure 18 The cyclic tensile properties curve of the polyethylene prepared in Example 17 is shown. Figure 19 The composite viscosity curves of the polyethylene prepared in Examples 14 and 17 are shown. Figure 20 Modulus curves for polyethylene prepared in Examples 14 and 17. Figures 17-20 It can be seen that the tensile strength of the polyethylene prepared in Example 14 is 19.28 MPa, and the tensile strength of the polyethylene prepared in Example 17 is 21.68 MPa.

[0183] The presence of low molecular weight components in the resulting bimodal ultra-high molecular weight polyethylene thermoplastic elastomer blends leads to differences in their mechanical properties compared to unimodal products (taking Examples 8 and 11 as examples). Figure 11The GPC curves show that the molecular weight of the sample in Example 8 is mainly distributed in the high molecular weight region, with an indistinct bimodal distribution, while the sample obtained in Example 11 has a high molecular weight region and a clear bimodal distribution. After tensile stress-strain testing, the high molecular weight components in the bimodal sample are highly similar to those in the unimodal polymer. The tensile strengths of these two materials reached 28.23 and 28.05 MPa, respectively, which are quite similar. However, their elastic responses differed significantly: the bimodal sample had an elongation at break as high as 778.01%, but a lower Young's modulus; while the unimodal material had a significantly higher modulus of 80.01 MPa, but a lower strain at fracture. These different behaviors stem from structural and compositional reasons. On the one hand, the unimodal polymer prepared at low temperatures has a lower degree of branching, resulting in higher crystallinity and thus exhibiting stronger and more ductile properties; while the bimodal material has a higher branch density and lower crystallinity, behaving more like an elastomer. On the other hand, the presence of the low molecular weight fraction in the bimodal polymer acts as an internal lubricant, promoting chain mobility and stress relaxation during deformation. Therefore, the yield strength of the bimodal sample is 10.27 MPa, followed by a gradual increase in stress over a significantly extended strain range. Further evidence of this enhanced elasticity comes from hysteresis experiments, in which the unimodal sample fractured in the first cycle when stretched to 300% strain, while the bimodal sample withstood deformation and exhibited 27% strain recovery. All these findings clearly indicate that the unimodal sample is more like a rigid plastic, while the bimodal sample possesses the flexibility, elasticity, and recovery capacity of an elastomer. The complex viscosity and storage modulus of the two samples were subsequently determined using a rotational rheometer in oscillatory mode within a temperature range of 80–180°C, a scan rate of 3°C / min, an angular frequency of 1.0 Hz, and a strain amplitude of 1%. The results are as follows: Figure 15 , Figure 16 As shown, the composite viscosity (η) The complex viscosity (G) and storage modulus (G′) gradually decrease with increasing temperature, exhibiting a sharp decline near their respective melting points. Notably, throughout the entire temperature range, the complex viscosity and storage modulus of the bimodal sample are consistently significantly lower than those of the unimodal sample, indicating a significant improvement in its melt processability. Given the high molecular weight match between the high molecular weight fraction in the bimodal polymer and the molecular weight fraction in the unimodal sample, this improved rheological behavior can be partly attributed to the presence of the low molecular weight fraction, which facilitates chain movement and reduces melt entanglement density.

[0184] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. The closed-loop semi-sandwich type containing axial benzene ring η shown in formula (II) 6 -Cat nickel catalysts with sterically hindered α-diimine ligands: In equation (II), R1 has the structure of equation (a): Equation (a); R2 and R3 are derived independently from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6. 20 One of the aromatic groups; R7 and R8 are independently selected from H, substituted or unsubstituted C1~C. 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; The substituents are independently selected from halogens or C1-C6 alkyl groups.

2. The catalyst according to claim 1, characterized in that, R2 is H; R3 is selected from H or C1~C6 alkyl groups; R4, R5 and R6 are H; R7 and R8 are C1~C6 alkyl groups.

3. The catalyst according to claim 2, characterized in that, R3 is selected from H, methyl, or tert-butyl; R7 and R8 are methyl.

4. The catalyst according to any one of claims 1 to 3, characterized in that, It has the structure of formulas (II-1) to (II-9): (II-1); (II-2); (II-3); (II-4); (II-5); (II-6); (II-7); (II-8); (II-9)。 5. A closed-ring semi-sandwich type containing an axial benzene ring η as described in any one of claims 1 to 4 6 A method for preparing a sterically hindered α-diimine cationic nickel catalyst with coordination, characterized in that... Includes the following steps: The ligand shown in formula (I), nickel acetylacetone, and [CPh3][B(C6F5)4] react to yield the closed-ring semi-sandwich type containing an axial benzene ring η shown in formula (II). 6 -Coordinated, sterically hindered α-diimine cationic nickel catalysts: Equation (I); In equation (I) or equation (II), R1 has the structure of equation (a): #imgpt13# Equation (a); R2 and R3 are derived independently from H, substituted or unsubstituted C1~C 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; R4, R5, and R6 are independently selected from H, halogen, hydroxyl, nitro, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted amino, and substituted or unsubstituted C6-C6. 20 One of the aromatic groups; R7 and R8 are independently selected from H, substituted or unsubstituted C1~C. 20 Alkyl groups and substituted or unsubstituted C6~C 20 One of the aromatic groups; The substituents are independently selected from halogens or C1-C6 alkyl groups.

6. The preparation method according to claim 5, characterized in that, The reaction was carried out at room temperature for 10 to 20 hours.

7. A catalyst composition comprising the closed-ring semi-sandwich type sterically hindered α-diimine cationic nickel catalyst according to any one of claims 1 to 4, or the closed-ring semi-sandwich type containing an axial benzene ring η prepared by the preparation method according to any one of claims 5 to 6. 6 -Coordinated, sterically hindered α-diimine cationic nickel catalysts and co-catalysts.

8. The catalyst composition according to claim 7, characterized in that, The cocatalyst includes one or more of methylaluminoxane, modified methylaluminoxane, alkylaluminum, and alkylaluminum chloride.

9. The catalyst composition according to claim 7 or 8, characterized in that, The closed-loop semi-sandwich type containing axial benzene ring η 6 - The molar ratio of nickel to co-catalyst in a well-coordinated, sterically hindered α-diimine cationic nickel catalyst is 1:20~4000.

10. A method for preparing an ultra-high molecular weight bimodal polyethylene thermoplastic elastomer, comprising the following steps: Ethylene undergoes polymerization under the action of a catalyst to obtain ultra-high molecular weight bimodal polyethylene thermoplastic elastomer; The catalyst comprises the closed-ring semi-sandwich type containing an axial benzene ring η as described in any one of claims 1 to 4. 6 -A sterically hindered α-diimine cationic nickel catalyst with coordination or a closed-ring semi-sandwich type containing an axial benzene ring η prepared by the preparation method according to any one of claims 5 to 6 6 -A sterically hindered α-diimine cationic nickel catalyst with coordination or the catalyst composition according to any one of claims 7 to 9.

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