A process for the preparation of semi-crystalline polar polyolefin materials by nickel catalysed long chain alpha-olefin chain walking polymerisation

Abstract

The application discloses a method for preparing semi-crystalline polar polyolefin materials by using a nickel catalyst to catalyze long-chain alpha-olefin chain extension polymerization. The semi-crystalline polyolefin material provided by the application uses an alpha-diimine nickel complex as a main catalyst, adds a cocatalyst to form a catalytic system, and can catalyze long-chain alpha-olefin and various polar monomers to copolymerize. Based on the chain extension polymerization mechanism of the catalyst, the semi-crystalline polar polyolefin material with a polyethylene-like structure can be obtained. The alpha-diimine nickel catalyst used in the method is cheap and easy to obtain. By regulating the steric hindrance of the nickel catalyst ligand, the type of long-chain alpha-olefin and the reaction condition, the melting point, the crystallinity and the polar monomer insertion rate of the obtained semi-crystalline polar polyolefin material can be regulated. By changing the type of copolymerization polar monomer, different polar functional groups can be introduced into the semi-crystalline polar polyolefin material, so that the diversified requirements for the structure and performance of the polymer can be met, and the method has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polyolefins, and more specifically, relates to a method for preparing semi-crystalline polar polyolefin materials by nickel-catalyzed long-chain α-olefin chain stretching polymerization. Background Technology

[0002] Long-chain α-olefins (linear-chain terminal olefins with four or more carbons) are abundant and versatile monomers that can be produced from petrochemical and sustainable bio-derived feedstocks. These monomers are primarily used in copolymerization with ethylene to produce linear low-density polyethylene (LLDPE). Homopolymerization of long-chain α-olefins using pre-transition metal catalysts (such as titanium and zirconium) generally yields non-crystallizable amorphous polyolefin materials with poor mechanical properties, often used as lubricants. In contrast, utilizing the unique "chain-walking" ability of post-transition metal catalysts (chain isomerization resulting from the reinsertion of polymer chains after β-H elimination), if a suitable catalytic system is selected, the regioselectivity of 2,1 insertion of long-chain α-olefins can be improved. Combined with the strong "chain-walking" ability of such catalytic systems, long-chain α-olefins can undergo "chain-stretching" polymerization, resulting in a structure similar to linear polyethylene (continuous methylene units) (see the following formula, the reaction mechanism of chain-stretching polymerization using 1-octene as an example). This significantly improves the melting point, crystallinity, and mechanical properties of the resulting material.

[0003]

[0004] On the other hand, commercially available polyolefin materials have non-polar chain structures. To improve important properties of polyolefin materials, such as surface properties, dyeability, adhesion, and compatibility and blendability with other polymers, introducing polar groups into the polyolefin chain structure to synthesize functionalized polar polyolefins has long been an important research direction in this field. Post-transition metal nickel-palladium catalysts exhibit high tolerance to polar functional groups, which makes the catalytic synthesis of polar polyolefin materials possible. The copolymerization of ethylene and polar monomers using a post-transition metal nickel-palladium catalyst based on diimine ligands has achieved considerable success in preparing semi-crystalline (semi-crystalline: capable of crystallization, but with relatively low crystallinity, not reaching the crystallinity of commercial high-density polyethylene HDPE) polar polyethylene materials (CCS Chemistry 2021, 3, 1598-1612; Angew. Chem. Int. Ed. 2015, 54, 9948-9953; Angew. Chem. Int. Ed. 2016, 55, 13281-13285; Angew. Chem. Int. Ed. 2021, 60, 24107-24115; Angew. Chem. Int. Ed. 2016, 55, 7106-7110). In the field of long-chain α-olefin polymerization, although the use of nickel or palladium catalysts for highly selective "chain-stretching" homopolymerization of long-chain α-olefins to obtain semi-crystalline polymers with polyethylene-like structures has been reported (J. Am. Chem. Soc. 2014, 136, 7213-7216; ACS Catal. 2015, 5, 122-128), reports on the use of such catalysts for copolymerization of long-chain α-olefins with polar monomers to obtain semi-crystalline polar polyolefin materials are extremely rare. Recently, the Coates group reported a sandwich-type palladium catalyst that, due to its high chain-stretching selectivity, can catalyze the copolymerization of the long-chain α-olefin 1-decene with the ester-containing polar monomer methyl 9-decenoate, thereby obtaining semi-crystalline polar polyethylene-like materials (Organometallics 2022, 41, 3411-3418). It should be noted that the palladium catalyst used in this system is a precious metal catalyst, which is expensive, has a complicated synthesis process, and is applicable to a limited range of polar monomers, making it unable to catalyze the copolymerization of long-chain α-olefins with the carboxyl-containing polar monomer 10-undecenoic acid. Therefore, finding inexpensive and readily available nickel catalysts for catalyzing the copolymerization of long-chain α-olefins with various polar monomers to obtain structurally tunable semi-crystalline polar polyolefin materials has become a problem that needs to be solved in this field. Currently, there are no reports on using inexpensive nickel catalysts to catalyze the copolymerization of long-chain α-olefins with polar monomers to obtain semi-crystalline polar polyolefin materials, because compared to palladium catalysts, nickel catalysts have weaker tolerance to polar functional groups in polar monomers. Summary of the Invention

[0005] The technical problem this invention aims to solve is the copolymerization of long-chain α-olefins with polar monomers catalyzed by nickel catalysts. Choosing a suitable nickel catalyst is more cost-effective than using a noble metal like palladium catalyst, and the synthesis steps are relatively simple. This invention provides a method for preparing semi-crystalline polar polyolefin materials by using an α-diimine nickel complex as the main catalyst to catalyze the chain-stretching polymerization of long-chain α-olefins with polar monomers. This method broadens the applicable range of polar monomers for copolymerization, simplifies the product flow, and simplifies the post-processing. Most importantly, these nickel catalysts can copolymerize long-chain α-olefins with polar monomers to generate various semi-crystalline polar copolymers containing multiple polar groups (such as ester and carboxyl groups) within the temperature range of 5.6–93°C, with an insertion rate of up to 11% for the polar monomers. This method has very promising application prospects in the field of nickel-catalyzed copolymerization of long-chain α-olefins with polar monomers to form semi-crystalline polar polyolefin materials.

[0006] The first objective of this invention is to provide a nickel catalyst for the copolymerization of long-chain α-olefins with polar monomers.

[0007] The second objective of this invention is to provide a method for preparing semi-crystalline polar polyolefin materials by nickel-catalyzed long-chain α-olefin chain stretching polymerization.

[0008] A third objective of this invention is to provide a semi-crystalline polar polyolefin material prepared according to the method described herein.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] First, this invention provides a catalyst system for preparing semi-crystalline polar polyolefin materials by nickel-catalyzed long-chain α-olefin chain straightening polymerization, comprising a main catalyst, a co-catalyst, and a polar monomer.

[0011] The main catalyst is an α-diimine nickel complex, the specific structural formula of which is shown in the figure below:

[0012]

[0013] Preferably, the co-catalyst is diethylaluminum chloride, methylaluminoxane, or modified methylaluminoxane.

[0014] More preferably, the co-catalyst is diethylaluminum chloride.

[0015] Preferably, the polar monomer is methyl 10-undecenoate, 10-undecenoic acid, methyl 9-decaenoate, acrylic acid, methyl acrylate, or 10-undecenool.

[0016] More preferably, the polar monomer is methyl 10-undecenoate and 10-undecenoic acid.

[0017] Preferably, the molar ratio of the main catalyst to the co-catalyst is 1:50 to 1000.

[0018] More preferably, the molar ratio of the main catalyst to the co-catalyst is 1:600.

[0019] Preferably, the molar ratio of the olefin to the polar monomer is 100:0.1 to 20.

[0020] More preferably, the molar ratio of the olefin to the polar monomer is 100:2 to 10.

[0021] In the above-mentioned catalytic system of the present invention, on the one hand, the α-diimine nickel catalyst system is cheaper and simpler to prepare than the α-diimine palladium catalyst; on the other hand, the addition of polar monomers can introduce polar groups, and semi-crystalline polar polyolefin materials can be obtained through highly selective chain-stretching polymerization of the catalyst.

[0022] Through the above-mentioned effective improvements, the present invention can obtain semi-crystalline polar polyolefin materials with high molecular weight and melting point, crystallinity, polar functional groups and adjustable polar monomer insertion rate during the copolymerization process of long-chain α-olefins.

[0023] In addition, based on the above-mentioned catalytic system, the present invention provides a method for preparing semi-crystalline polar polyolefin materials by nickel-catalyzed long-chain α-olefin chain straightening polymerization. The method uses an α-diimine nickel complex as the main catalyst, adds a co-catalyst and a polar monomer to form a catalytic system, and catalyzes the copolymerization reaction of long-chain α-olefins and polar monomers to obtain semi-crystalline polar polyolefin materials.

[0024] Preferably, the temperature of the copolymerization reaction is 0–100°C.

[0025] More preferably, the copolymerization reaction is carried out at a temperature of 25°C.

[0026] Preferably, the copolymerization reaction time is 0.1 to 24 hours. More preferably, the copolymerization reaction time is 15 minutes, 1 hour, or 8 hours.

[0027] Preferably, the solvent for the copolymerization reaction is toluene or dichloromethane. More preferably, the solvent for the copolymerization reaction is toluene.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention uses a simple and readily available inexpensive nickel catalyst to catalyze the copolymerization of long-chain α-olefins with polar monomers to obtain a semi-crystalline polar polyolefin material with a structure similar to polyethylene, and the obtained polymer contains polar groups.

[0030] (2) In this invention, by changing the structure of the nickel catalyst, the type of long-chain α-olefin, and the reaction conditions, the melting point and polar monomer insertion rate of the resulting semi-crystalline polar polyolefin material can be controlled (melting point: 5.6–93 °C; polar monomer insertion rate: 1.8–11%). By changing the type of copolymer polar monomer, different polar functional groups can be introduced into the semi-crystalline polar polyolefin material to meet the needs of diverse copolymer structures and properties.

[0031] (3) The polymer synthesis method in this invention is mild and can be prepared at high monomer concentrations. The post-processing is simple and the product is easy to separate, which greatly simplifies the process flow. Attached image description:

[0032] Figure 1 The image shows the proton NMR spectrum of the copolymer obtained in Example 1 of this invention.

[0033] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the copolymer obtained in Example 2 of the present invention.

[0034] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the copolymer obtained in Example 4 of the present invention.

[0035] Figure 4 This is the 1H NMR spectrum of the copolymer obtained in Example 6 of the present invention.

[0036] Figure 5 The image shows the proton NMR spectrum of the copolymer obtained in Example 7 of this invention.

[0037] Figure 6 This is the 1H NMR spectrum of the copolymer obtained in Example 8 of the present invention.

[0038] Figure 7 This is the hydrogen nuclear magnetic resonance spectrum of the copolymer obtained in Example 9 of the present invention.

[0039] Figure 8 This is a DSC diagram of the copolymer obtained in Example 1 of the present invention.

[0040] Figure 9 This is a DSC diagram of the copolymer obtained in Example 2 of the present invention.

[0041] Figure 10 This is a DSC diagram of the copolymer obtained in Example 4 of the present invention.

[0042] Figure 11 This is a DSC diagram of the copolymer obtained in Example 6 of the present invention.

[0043] Figure 12 This is a DSC diagram of the copolymer obtained in Example 7 of the present invention.

[0044] Figure 13 This is a DSC diagram of the copolymer obtained in Example 8 of the present invention.

[0045] Figure 14 This is a DSC diagram of the copolymer obtained in Example 9 of the present invention. Detailed implementation method:

[0046] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0047] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0048] In the following examples, the number-average molecular weight M of the prepared polymer was determined by gel permeation chromatography (GPC). n Unit g·mol -1 The molecular weight distribution index (PDI) was also measured. Melting point and crystallinity were determined by differential scanning calorimetry (DSC). The sample was rapidly heated to 150 °C, held for 5 min to remove thermal history, then cooled to -70 °C at a rate of 10 °C / min, and finally reheated to 150 °C at the same rate under a nitrogen flow (50 mL / min). The maximum absorbance point (heating scan) was taken as the melting point (T). m Branching degree, measured as the number of branches per 1000 carbon atoms, is determined by proton nuclear magnetic resonance (NMR) spectroscopy. 1 The polar monomer insertion rate can also be obtained through ¹H NMR (hydrogen permeation) testing. 1 The determination was performed using ¹H NMR. The nickel diimine catalyst can be easily prepared from commercially available raw materials.

[0049] Example 1: Preparation of semi-crystalline polar polyolefin materials

[0050] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0051] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni0 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0052] 2. Results

[0053] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 2120, and the number-average molecular weight is 3.9 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.34, melting point T m =5.6℃ and 30.6℃, crystallinity is 3%, branching degree is 79 / 1000C, and methyl 10-undecenoate insertion rate is 2.0%.

[0054] Example 2: Preparation of semi-crystalline polar polyolefin materials

[0055] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0056] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0057] 2. Results

[0058] In this embodiment, the catalytic activity (TON) of the catalytic system is 2184, and the number-average molecular weight is 8.2 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.16, melting point T m =37℃, crystallinity 4%, branching degree 72 / 1000C, methyl 10-undecenoate insertion rate 2.1%.

[0059] Example 3: Preparation of semi-crystalline polar polyolefin materials

[0060] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0061] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 2.25 g of hexene, 3 g of octene, 0.24 mL of methyl 10-undecenoate ([hexene]:[octene]:[methyl 10-undecenoate] = 50:50:2, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0062] 2. Results

[0063] In this embodiment, the catalytic activity (TON) of the catalytic system is 1472, and the number-average molecular weight is 5.6 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.22, melting point T m =29℃, crystallinity is 4%, branching degree is 74 / 1000C, and methyl 10-undecenoate insertion rate is 2%.

[0064] Example 4: Preparation of semi-crystalline polar polyolefin materials

[0065] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0066] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of Ni2 catalyst were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0067] 2. Results

[0068] In this embodiment, the catalytic activity (TON) of the catalytic system is 840, and the number-average molecular weight is 9.1 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.14, melting point T m =15℃, crystallinity is 3%, branching degree is 78 / 1000C, and methyl 10-undecenoate insertion rate is 3%.

[0069] Example 5: Preparation of semi-crystalline polar polyolefin materials

[0070] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0071] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.20 mL of 10-undecenoic acid ([octene]:[10-undecenoic acid] = 100:2, molar ratio), and 30 μmol of Ni2 catalyst were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0072] 2. Results

[0073] In this embodiment, the catalytic activity (TON) of the catalytic system is 800, and the number-average molecular weight is 8.2 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.19, melting point T m =16℃, crystallinity is 4%, branching degree is 73 / 1000C, and 10-undecenoic acid insertion rate is 2.6%.

[0074] Example 6: Preparation of semi-crystalline polar polyolefin materials

[0075] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0076] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni2' were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0077] 2. Results

[0078] In this embodiment, the catalytic activity (TON) of the catalytic system is 1872, and the number-average molecular weight is 8.3 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.29, melting point T m =54℃, crystallinity is 7%, branching degree is 59 / 1000C, and methyl 10-undecenoate insertion rate is 2.8%.

[0079] Example 7: Preparation of semi-crystalline polar polyolefin materials

[0080] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0081] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni3 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0082] 2. Results

[0083] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 992, and the number-average molecular weight is 12 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 1.69, melting point T m =46℃, crystallinity is 6%, branching degree is 58 / 1000C, and methyl 10-undecenoate insertion rate is 2.8%.

[0084] Example 8: Preparation of semi-crystalline polar polyolefin materials

[0085] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0086] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of Ni4 catalyst were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0087] 2. Results

[0088] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 40, and the number-average molecular weight is 2.6 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 1.31, melting point T m =85℃, crystallinity is 24%, branching degree is 28 / 1000C, and methyl 10-undecenoate insertion rate is 8.8%.

[0089] Example 9: Preparation of semi-crystalline polar polyolefin materials

[0090] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0091] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 7.5 g of decene, 0.24 mL of methyl 10-undecenoate ([decene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of Ni4 catalyst were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0092] 2. Results

[0093] In this embodiment, the catalytic activity (TON) of the catalytic system is 48, and the number-average molecular weight is 2.2 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 1.33, melting point T m =85℃ and 93℃, crystallinity is 25%, branching degree is 23 / 1000C, and methyl 10-undecenoate insertion rate is 11%.

[0094] Example 10: Preparation of semi-crystalline polar polyolefin materials

[0095] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0096] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 4 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0097] 2. Results

[0098] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 2152, and the number-average molecular weight is 7.9 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.31, melting point T m =38℃, crystallinity is 5%, branching degree is 71 / 1000C, and methyl 10-undecenoate insertion rate is 2%.

[0099] Example 11 Preparation of semi-crystalline polar polyolefin materials

[0100] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0101] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 1 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0102] 2. Results

[0103] In this embodiment, the catalytic activity (TON) of the catalytic system is 1485, and the number-average molecular weight is 7.6 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.0, melting point T m =25℃, crystallinity is 3%, branching degree is 72 / 1000C, and methyl 10-undecenoate insertion rate is 2%.

[0104] Example 12 Preparation of semi-crystalline polar polyolefin materials

[0105] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0106] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 15 min. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0107] 2. Results

[0108] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 330, and the number-average molecular weight is 3.1 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 1.99, melting point T m =28℃, crystallinity is 4%, branching degree is 74 / 1000C, and methyl 10-undecenoate insertion rate is 1.8%.

[0109] Example 13 Preparation of semi-crystalline polar polyolefin materials

[0110] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0111] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.24 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:2, molar ratio), and 30 μmol of catalyst Ni0 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 15 min. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0112] 2. Results

[0113] In this embodiment, the catalytic activity (TON) of the catalytic system is 456, and the number-average molecular weight is 2.7 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.26, melting point T m =6.7℃, crystallinity is 3%, branching degree is 80 / 1000C, and methyl 10-undecenoate insertion rate is 1.9%.

[0114] Example 14 Preparation of semi-crystalline polar polyolefin materials

[0115] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0116] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 0.72 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:6, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0117] 2. Results

[0118] In this embodiment, the catalytic activity (TON) of the catalytic system is 1091, and the number-average molecular weight is 4.6 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 2.01, melting point T m =38℃, crystallinity is 4%, branching degree is 71 / 1000C, and methyl 10-undecenoate insertion rate is 6%.

[0119] Example 15 Preparation of semi-crystalline polar polyolefin materials

[0120] 1. Preparation Experiment of Semi-crystalline Polar Polyolefin Materials

[0121] Under anhydrous and oxygen-free conditions, 2 mL of anhydrous toluene, 15 mmol of diethylaluminum chloride, 6 g of octene, 1.20 mL of methyl 10-undecenoate ([octene]:[methyl 10-undecenoate] = 100:10, molar ratio), and 30 μmol of catalyst Ni1 were added to a reaction flask. The copolymerization reaction was carried out at 25 °C for 8 h. The reaction was terminated with a methanol solution acidified with 5% hydrochloric acid. The polymer precipitated in methanol, filtered, washed three times with methanol, and dried to constant weight in a vacuum oven to obtain a semi-crystalline polar polyolefin material.

[0122] 2. Results

[0123] In this embodiment, the catalytic activity TON (conversion number) of the catalytic system is 545, and the number-average molecular weight is 3.5 × 10⁻⁶. 4 g·mol -1 Molecular weight distribution index (PDI) = 1.99, melting point T m =39℃, crystallinity is 4%, branching degree is 69 / 1000C, and methyl 10-undecenoate insertion rate is 9%.

[0124] Example 16

[0125] The olefin is selected as an α-olefin with four or five carbons, a suitable polar monomer is selected, and a suitable catalyst (e.g., Ni4) is selected. Through experiments, it can be verified that semi-crystalline polar polyolefin materials can be prepared within the reaction conditions provided by this invention.

[0126] The olefin is selected as a long-chain α-olefin with six or more carbons, and the polar monomer is selected as methyl 10-undecenoate (CH2=CH(CH2)8COOCH3), 10-undecenoic acid (CH2=CH(CH2)8COOH), methyl 9-decaenoate (CH2=CH(CH2)7COOCH3), acrylic acid (CH2=CHCOOH), methyl acrylate (CH2=CHCOOCH3), or 10-undecenool (CH2=CH(CH2)9OH). Any catalyst can be selected. Through experiments, it can be verified that within the reaction conditions provided by this invention, semi-crystalline polar polyolefin materials can be prepared, and their melting point and insertion rate can be controlled.

[0127] The data settings for each embodiment are shown in the table below:

[0128]

[0129] The table shows the structural formulas for hexene (CH2=CH(CH2)3CH3), octene (CH2=CH(CH2)5CH3), decene (CH2=CH(CH2)7CH3), methyl 10-undecenoate (CH2=CH(CH2)8COOCH3), and 10-undecenoic acid (CH2=CH(CH2)8COOH). The monomer feed ratios are molar ratios. TON represents the conversion number, a measure of catalytic activity. M n This represents the number-average molecular weight of the polymer. PDI stands for molecular weight distribution index.

[0130] As can be seen from the various examples, the polymers obtained by Ni4 catalysis containing the sterically hindered ligand have the highest melting point, crystallinity, and polar monomer insertion rate. Generally, the molecular weight of copolymers of olefins and polar monomers tends to decrease significantly, but the number-average molecular weight of the copolymers obtained in this system still reaches over 22,000, with the highest reaching 120,000, indicating a high molecular weight. This shows that the nickel catalyst in this invention has good resistance to polar functional groups in the copolymerization of long-chain α-olefins and polar monomers. Examples 2, 14, and 15 show that increasing the proportion of polar monomers can increase the polar monomer insertion rate of the obtained polymers. Examples 8 and 9 show that using olefins with more carbon atoms to copolymerize with polar monomers can improve the melting point and crystallinity of the obtained polymers.

[0131] As can be seen from the above embodiments, the melting point and polar monomer insertion rate of the semi-crystalline polar polyolefin material can be controlled by changing the steric hindrance of the substituents on the main catalyst ligand, the type of long-chain α-olefin (1-octene and 1-decene), and the reaction conditions (feed ratio, reaction time). (Melting point: 5.6–93°C; Polar monomer insertion rate: 1.8–11%). Furthermore, by changing the type of copolymer polar monomer (methyl 10-undecenoate, 10-undecenoic acid), different polar functional groups can be introduced into the semi-crystalline polar polyolefin material, thereby meeting the demand for diverse structures and properties of the resulting semi-crystalline polar polyolefin material.

[0132] The above embodiments of the invention are merely examples for clearly illustrating the invention, and are not intended to limit the implementation of the invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the invention without departing from the scope of the invention shall still fall within the scope of the invention.

Claims

1. A method for preparing semi-crystalline polar polyolefin materials by nickel-catalyzed long-chain α-olefin chain stretching polymerization, characterized in that, Using α-diimine nickel complex as the main catalyst and adding co-catalyst to form a catalytic system, a copolymerization reaction of long-chain α-olefins and polar monomers is catalyzed to obtain semi-crystalline polar polyolefin materials. The long-chain α-olefins are straight-chain terminal olefins with four or more carbon atoms; The co-catalyst is diethylaluminum chloride, methylaluminoxane, or modified methylaluminoxane; The polar monomer is methyl 10-undecenoate, methyl 10-undecenoic acid, methyl 9-decaenoate, acrylic acid, methyl acrylate, or 10-undecenool. The structural formula of the main catalyst α-diimine nickel complex is shown below: R1, R2, R3, and R4 are each independently selected from methyl or p-methylphenyl. The molar ratio of long-chain α-olefins to polar monomers is 100:0.1 to 20.

2. The method for preparing semi-crystalline polar polyolefin materials according to claim 1, characterized in that, The molar ratio of the main catalyst to the co-catalyst is 1:50 to 1000.

3. The method for preparing semi-crystalline polar polyolefin materials according to claim 1, characterized in that, The conditions for the copolymerization of the long-chain α-olefin are: temperature 0–100℃, time 0.1–24 h.

4. The method for preparing semi-crystalline polar polyolefin materials according to claim 1, characterized in that, The structural formula of the main catalyst α-diimine nickel complex is: 。 5. The semi-crystalline polar polyolefin material prepared by the method according to any one of claims 1 to 4.

6. The semi-crystalline polar polyolefin material according to claim 5, characterized in that, The number-average molecular weight is 2.2 × 10⁻⁶. 4 ~12×10 4 g·mol -1 The molecular weight distribution index (PDI) is 1.31–2.34, the melting point is 5.6℃–93℃, the crystallinity is 3–25%, the branching degree is 23–80 / 1000℃, and the polar monomer insertion rate is 1.8–11%.

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