A high molecular weight carbon dioxide-based elastomer, a crosslinked carbon dioxide-based elastomer, and a method for preparing the same

Abstract

The application provides a high-molecular-weight carbon dioxide-based elastomer, a crosslinked carbon dioxide-based elastomer and a preparation method thereof. The application adopts a composite catalyst system comprising a homogeneous catalyst and a heterogeneous catalyst to prepare the high-molecular-weight carbon dioxide-based elastomer. Through the synergistic effect of the homogeneous catalyst and the heterogeneous catalyst, the technical problems of low catalytic activity, unstable reaction process and insufficient molecular weight of products in the prior art are overcome, and the elastomer material with high molecular weight and excellent mechanical properties is obtained.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a high molecular weight carbon dioxide-based elastomer, a cross-linked carbon dioxide-based elastomer, and their preparation methods. Background Technology

[0002] Utilizing carbon dioxide (CO2) as a raw material to prepare polymer materials has become an important research direction in the chemical industry, offering advantages such as carbon sequestration and waste-to-resource conversion. However, current research on CO2-based copolymers mainly focuses on the development of rigid materials, such as polycarbonate (PPC) and polycyclohexene carbonate (PCHO), with relatively little research in the field of elastomers. Compared to rigid materials, elastomers have a wide range of applications in the automotive, construction, medical, and electronics industries due to their unique deformation recovery capabilities, excellent fatigue resistance, and processability. Therefore, developing high-performance CO2-based elastomers is of great significance for broadening the application scope of carbon dioxide resource utilization.

[0003] Carbon dioxide-based plastics typically have high glass transition temperatures (Tg), exhibiting strong rigidity and mechanical strength at room temperature, making them suitable for engineering plastics and packaging materials. Generally, it's necessary to find ways to increase the Tg of carbon dioxide-based plastics to ensure their performance; while carbon dioxide-based elastomers need to maintain a low Tg at room temperature (usually below 0°C) to provide excellent elasticity and flexibility.

[0004] To lower the tensile strength (Tg) and maintain the elasticity of materials at room temperature, epoxy monomers with long side groups are typically introduced into the polymer backbone. However, these monomers have large molecular structures and high steric hindrance, and commonly used catalysts often exhibit low activity in the presence of long side-group monomers, leading to a decrease in polymerization rate and difficulty in generating high molecular weight polymers [J. Polym. Sci. Part A: Polym. Chem., 2015, 53, 737; Macromol. Symp. 2005, 224, 181.; ACS Macro Lett. 2022, 11, 945]. Molecular weight is one of the key parameters determining polymer properties. Generally, high molecular weight CO2-based polymers typically exhibit superior mechanical properties, thermal stability, and processability. In elastomer applications, increasing molecular weight can effectively improve the tensile strength, toughness, and resilience of materials, enhance their service life, and expand their application range. However, existing catalytic systems often struggle to obtain high molecular weight polymers when synthesizing CO2-based elastomers. This is mainly attributed to insufficient catalyst activity, poor selectivity, and a high proportion of side reactions, which directly affect the efficiency of the polymerization reaction and the molecular weight and distribution of the final product. Therefore, developing novel catalytic systems that can efficiently control the polymerization process and increase the molecular weight of the target product is crucial for the research of CO2-based elastomers.

[0005] Catalyst systems for CO2-based polymer synthesis are currently classified into two main categories: homogeneous catalysts and heterogeneous catalysts. Bimetallic catalysts are a type of heterogeneous catalyst that has been extensively studied and industrially applied. These catalysts exhibit high catalytic activity and can effectively promote the copolymerization reaction of epoxy monomers with CO2. However, bimetallic catalysts still face several challenges in practical applications. For example, their reaction induction period is relatively long, requiring a considerable amount of time to achieve efficient catalysis. Furthermore, the catalytic process often involves the formation of a high proportion of ether segments (approximately 40%) (SusMat.2021; 1:91), resulting in poor selectivity for polycarbonate, a low molecular weight of the final product, and a wide molecular weight distribution (patent CN 114479045A), which fails to meet the application requirements of high-performance elastomers.

[0006] Aluminum porphyrin and Salen Co catalysts are currently considered typical homogeneous catalytic systems. Salen Co catalysts exhibit extremely high catalytic activity in the copolymerization of cyclopropane and CO2; however, their selectivity decreases significantly when dealing with epoxides containing long side groups, leading to a substantial reduction in the polymerization rate (Patent CN1560111A). Aluminum porphyrin catalysts show high selectivity in the copolymerization of CO2 and long-side-group epoxides, resulting in polymers without ether segments, 100% polycarbonate structure, and a narrow molecular weight distribution. However, due to limitations in their catalytic mechanism, a high proportion of cyclic byproducts are easily generated during the reaction, ultimately making it difficult to obtain high molecular weight polymers (Macromol. Chem. Phys. 2022, 223, 2100403).

[0007] The existing technology has the following shortcomings in the preparation of carbon dioxide-based elastomers: (1) The homogeneous catalyst has low catalytic activity, resulting in a slow polymerization rate and limiting the polymerization efficiency; in addition, it has poor selectivity for long side-group epoxy monomers, which easily leads to side reactions and makes it difficult to obtain high molecular weight polymers. (2) Although the heterogeneous catalyst has high catalytic activity, its reaction induction period is long, and once the reaction is initiated, the rate may be too fast or even runaway, affecting the stability of the reaction and ultimately leading to a decrease in the mechanical properties and processing properties of the obtained polymer.

[0008] Therefore, how to effectively combine the advantages of homogeneous and heterogeneous catalysts to develop efficient and stable catalytic systems for the preparation of carbon dioxide-based elastomers with high molecular weight, low Tg, and excellent mechanical properties has become a key technical challenge that urgently needs to be solved. Summary of the Invention

[0009] This invention addresses the aforementioned problems in the prior art by proposing a catalyst system and its preparation method for preparing high molecular weight carbon dioxide-based elastomers, particularly suitable for the field of elastomer materials. Through the combination of homogeneous and heterogeneous catalysts, and utilizing their synergistic catalytic effect, the catalytic activity of the polymerization reaction, the carbonate unit content of the polymer, and its molecular weight are significantly improved.

[0010] One objective of this invention is to provide a high molecular weight carbon dioxide-based elastomer, which is obtained by polymerization of components including carbon dioxide and epoxy compounds under the action of a composite catalyst, wherein the composite catalyst includes a homogeneous catalyst, a heterogeneous catalyst, and a co-catalyst.

[0011] According to the present invention, in the high molecular weight carbon dioxide-based elastomer:

[0012] The epoxy compound comprises a saturated epoxy compound and an unsaturated epoxy compound; preferably, the saturated epoxy compound is selected from at least one of C3-12 saturated alkyl epoxy compounds, and the unsaturated epoxy compound is selected from at least one of unsaturated glycidyl ether compounds; more preferably, the saturated epoxy compound is selected from at least one of epoxide, epoxide, and epoxide octane; the unsaturated epoxy compound is selected from at least one of allyl glycidyl ether and glycidyl methacrylate; the molar ratio of the saturated epoxy compound to the unsaturated epoxy compound is 1:(0.01-0.5), preferably 1:(0.05-0.3);

[0013] The homogeneous catalyst is aluminum porphyrin;

[0014] The heterogeneous catalyst is selected from bimetallic catalysts, preferably Zn-Co bimetallic cyanide;

[0015] The co-catalyst is bis-(triphenylphosphine)ammonium chloride (PPNCl);

[0016] The mass ratio of the homogeneous catalyst, heterogeneous catalyst, and co-catalyst is 1:(0.05-0.7):(0.2-1.5), preferably 1:(0.1-0.5):(0.3-0.9).

[0017] The second objective of this invention is to provide a method for preparing the above-mentioned high molecular weight carbon dioxide-based elastomer, which includes heating and polymerizing components containing the aforementioned carbon dioxide, epoxy compound, and composite catalyst, followed by post-treatment to obtain the high molecular weight carbon dioxide-based elastomer.

[0018] According to an embodiment of the present invention, in the method for preparing the high molecular weight carbon dioxide-based elastomer:

[0019] In the composite catalyst, the heterogeneous catalyst is used in an amount of 0.002–0.12 wt% of the total epoxide compound, preferably 0.008–0.1 wt%; the homogeneous catalyst is used in an amount of 0.005–0.35 wt% of the total epoxide compound, preferably 0.01–0.28 wt%; and the co-catalyst is used in an amount of 0.005–0.25 wt% of the total epoxide compound, preferably 0.01–0.20 wt%.

[0020] The polymerization reaction is carried out at a temperature of 50–80°C, preferably 55–70°C.

[0021] The pressure of the polymerization reaction is 2-6 MPa, preferably 3-5 MPa;

[0022] The polymerization reaction takes 1 to 24 hours, preferably 4 to 16 hours.

[0023] The post-treatment includes the steps of dissolving, precipitating, and drying; preferably, the dissolving solvent is selected from at least one of polar solvents, preferably from at least one of dichloromethane and tetrahydrofuran; the precipitation solvent is selected from at least one of alcohols, preferably from at least one of methanol and ethanol; the drying temperature is 25-60°C, preferably 30-40°C.

[0024] This invention overcomes the technical difficulties of low catalytic activity, unstable reaction process, and low product molecular weight in the prior art through the synergistic effect of homogeneous and heterogeneous catalysts. Specifically, it is manifested in the following ways:

[0025] (1) Synergistic effect of homogeneous catalysts and heterogeneous catalysts

[0026] This invention significantly improves the overall efficiency and stability of the catalytic system by rationally combining homogeneous catalysts (such as aluminum porphyrin) and heterogeneous catalysts (such as Zn-Co bimetallic cyanides). It leverages the efficient initiation capability of the homogeneous catalyst and the stable catalytic effect of the heterogeneous catalyst in subsequent reaction stages. Specifically, the homogeneous catalyst rapidly initiates the polymerization reaction between epoxides and carbon dioxide, while its well-designed molecular structure ensures high selectivity and structural controllability of the initial product. The heterogeneous catalyst plays a crucial role in the later stages of the reaction, stably promoting chain growth and ensuring an increase in polymer molecular weight. Combining homogeneous and heterogeneous catalysts in the preparation of carbon dioxide-based elastomers achieves a synergistic effect in the catalytic system.

[0027] (2) Controllable reaction system

[0028] By adjusting the ratio of homogeneous to heterogeneous catalysts, catalyst loading, type and ratio of epoxy monomers, and reaction conditions (such as temperature, pressure, and reaction time), this invention can effectively control the microstructure, molecular weight, and distribution of the product, and prepare carbon dioxide-based elastomers with high molecular weight and excellent mechanical properties.

[0029] The third objective of this invention is to provide a high molecular weight carbon dioxide-based elastomer obtained by the above preparation method. Preferably, the number average molecular weight of the high molecular weight carbon dioxide-based elastomer is 50-180 kg / mol, and more preferably 80-150 kg / mol.

[0030] The fourth objective of this invention is to provide a crosslinked carbon dioxide-based elastomer, which is prepared from a high molecular weight carbon dioxide-based elastomer, wherein the high molecular weight carbon dioxide-based elastomer is the aforementioned high molecular weight carbon dioxide-based elastomer.

[0031] The fifth objective of this invention is to provide a method for preparing the above-mentioned crosslinked carbon dioxide-based elastomer, comprising the step of preparing the crosslinked carbon dioxide-based elastomer by initiating a reaction of the high molecular weight carbon dioxide-based elastomer; specifically, the method includes the following steps: mixing the high molecular weight carbon dioxide-based elastomer and an initiator, and then subjecting the mixture to a crosslinking reaction by heating to obtain the crosslinked carbon dioxide-based elastomer; wherein, the mixing is optionally carried out in a solvent.

[0032] According to an embodiment of the present invention, in the method for preparing the crosslinked carbon dioxide-based elastomer:

[0033] The initiator is selected from at least one of peroxide initiators, preferably from at least one of dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-tert-butylhexane peroxide;

[0034] The solvent is selected from at least one of tetrahydrofuran, dichloromethane, and toluene. The amount of solvent used is not particularly limited and can be adjusted within a wide range according to commonly used amounts.

[0035] The amount of the initiator is 0.03 to 0.20 wt% of the amount of high molecular weight carbon dioxide-based elastomer, preferably 0.05 to 0.15 wt%.

[0036] The temperature of the crosslinking reaction is 120–210°C, preferably 150–180°C;

[0037] The pressure of the crosslinking reaction is 10-20 MPa, preferably 13-17 MPa.

[0038] This invention employs a composite catalytic system combining homogeneous and heterogeneous catalysts for the efficient preparation of high molecular weight carbon dioxide-based elastomers. Through the synergistic effect of the homogeneous and heterogeneous catalysts, this invention offers the following beneficial effects:

[0039] (1) The technical solution of the present invention significantly improves the activity and reaction efficiency of the catalytic system through the efficient initiation of the homogeneous catalyst and the stable promoting effect of the heterogeneous catalyst. Compared with the traditional heterogeneous catalytic process, the reaction induction period is shortened to 50%, and the reaction time is shortened to 50% to 80% of that of the homogeneous catalytic process under the same monomer conversion rate.

[0040] (2) The technical solution of the present invention optimizes the stability of the reaction process and suppresses the excessively fast catalytic rate of the heterogeneous catalyst, thereby effectively avoiding the problem of reduced polycarbonate content caused by uncontrolled reaction.

[0041] (3) The compound catalytic system of the present invention effectively avoids the problem of molecular weight limitation when homogeneous catalysts and heterogeneous catalysts are used alone, and the number-average molecular weight M of the prepared carbon dioxide-based elastomer is high. n It can reach 50-180 kg / mol.

[0042] (4) The catalytic system of the present invention is applicable to the polymerization reaction of various epoxides (such as epoxy octane, epoxy butane, allyl glycidyl ether) and carbon dioxide, and has strong versatility, laying the foundation for further development of multifunctional carbon dioxide-based polymer materials. Attached Figure Description

[0043] Figure 1 The curves show the conversion rate of 1,2-epoxyhexane monomer as a function of reaction time in Example 1 and Comparative Examples 1-2. Figure 1 It can be seen that in Example 1, the polymerization induction period was 1 hour, and the conversion rate of 1,2-epoxyhexane monomer reached 80% after 6 hours of reaction; in Comparative Example 1, the reaction had almost no induction period, and the conversion rate of 1,2-epoxyhexane monomer was only 30%; in Comparative Example 2, the reaction induction period was >2 hours.

[0044] Figure 2 The GPC curves are for the carbon dioxide-based elastomers obtained in Example 1 and Comparative Examples 1-2. Figure 2 As can be seen, the GPC curve of the product of Comparative Example 1 is bimodal, with the peak corresponding to a long retention time (low molecular weight) and a narrow distribution, indicating that the product has a low molecular weight and a narrow distribution; the GPC curve of the product of Comparative Example 2 is unimodal, with the peak corresponding to a long retention time (low molecular weight) and a wide distribution; the GPC curve of the product of Example 1 is widely distributed, and the peak of the main product corresponds to a short retention time, indicating that the product has a high molecular weight.

[0045] Figure 3The GPC curves of the carbon dioxide-based elastomer obtained at different times during the polymerization reaction of Example 1 are shown. In the initial stage of the reaction (<1.5h), the reaction rate is slow, and the GPC curve shows a bimodal distribution, indicating that the copolymerization reaction is initiated by aluminum porphyrin. As the reaction time increases (>1.5h), the reaction rate increases due to the joint participation of Zn-Co bimetallic cyanide and aluminum porphyrin in the chain growth reaction, and the GPC curve shows a trimodal distribution. This demonstrates the synergistic effect of homogeneous catalysts rapidly initiating the reaction and heterogeneous catalysts stably promoting polymerization.

[0046] Figure 4 The mechanical property curves of the crosslinked carbon dioxide-based elastomers obtained in Example 1 and Comparative Examples 1-2 are shown. Figure 4 This indicates that the cross-linked carbon dioxide-based elastomer prepared using the complex catalytic system in Example 1 exhibits higher stress and strain. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0048] The testing instruments and conditions used in this embodiment are as follows:

[0049] Monomer conversion rate: Bruker AV600 nuclear magnetic resonance spectrometer ( 1 ¹H NMR was performed using deuterated chloroform (CDCl₃) as solvent and tetramethylsilane (TMS) as internal standard. 1 H NMR integral analysis was used to analyze the changes in monomer characteristic peaks and calculate the conversion rate.

[0050] Molecular weight: Number-average molecular weight (Mn) and molecular weight distribution index (PDI) were determined by gel permeation chromatography (GPC). A Waters 515 GPC instrument equipped with Waters Styragel HT3, HT5, and HT6 series columns was used, with tetrahydrofuran (THF) as the mobile phase and a flow rate set to 1.0 mL / min. Monodisperse polystyrene standards were used for calibration, covering a molecular weight range from 1620 to 8500 kDa.

[0051] Tensile testing: Tensile strength and elongation at break were determined using a computer-controlled electronic universal testing machine (Zwick / Roell, Txet-port II, Germany) at a speed of 50 mm / min and a temperature of 25°C. Specimen dimensions were prepared according to ISO 37:2005, with a narrow parallel section length of 20 mm and a width of 4 mm. Each specimen was tested three times, and the mechanical properties were evaluated based on the test results.

[0052] Thermal performance analysis: The glass transition temperature T of the polymer was determined by differential scanning calorimetry (DSC) using a Mettler Toledo DSC instrument under a nitrogen atmosphere. g The sample was first heated to 100°C at a heating rate of 10°C / min and held at that temperature for 5 minutes; then cooled to -100°C at a cooling rate of 10°C / min and reheated to 100°C at the same heating rate.

[0053] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0054] Preparation method of aluminum porphyrin catalyst:

[0055] Under argon protection, 0.7 mL of distilled pyrrole and 1.41 g of p-chlorobenzaldehyde were added to 400 mL of distilled dichloromethane, followed by the addition of 0.7 mL of trifluoroacetic acid. After stirring at 25 °C for 1 h, 4.54 g of dichlorodicyanobenzoquinone (DDQ) was added, and the mixture was stirred for another 1 h before filtration. The filtrate was subjected to vacuum distillation to remove dichloromethane, yielding a purplish-black solid. The solid was then separated by chromatographic column chromatography (stationary phase: neutral alumina; mobile phase: V(dichloromethane):V(petroleum ether) = 1:1) to obtain the ligand. Under argon protection, 20 mL of dichloromethane was added to a 50 mL round-bottom three-necked flask containing 0.753 g of ligand. The mixture was stirred at 25 °C until the ligand was completely dissolved. Then, 1.3 mL of a hexane solution of diethylaluminum chloride (1 mol / L) was added. After stirring at 25 °C for 1 h, the solvent was evaporated using a rotary evaporator. The crude product was separated by chromatographic column chromatography (stationary phase: neutral alumina; mobile phase: V(dichloromethane):V(methanol) = 10:1) to obtain the catalyst used for polymerization.

[0056] Preparation method of zinc-cobalt bimetallic cyanide:

[0057] 1.33g of K3Co(CN)6 was dissolved in 20mL of deionized water to form an aqueous solution of K3Co(CN)6, and 3.26g of ZnCl2 was dissolved in 60mL of deionized water and 30mL of tBuOH to form a mixed solution of ZnCl2. At 50℃, a ZnCl2 mixed solution was stirred mechanically at 300 rpm. Simultaneously, 20 mL of K3Co(CN)6 aqueous solution was added dropwise to the ZnCl2 mixed solution over 1 hour using a constant-pressure dropping funnel. After the addition was complete, stirring continued under these conditions for another hour. The filter cake was then separated by centrifugation at 5000 rpm for 5 minutes. The filter cake was then washed and slurried for 30 minutes at 50℃ and 300 rpm with a mixed solution of 30 mL tBuOH and 30 mL deionized water. This washing and slurrying process was repeated, with the amounts of tBuOH and deionized water gradually changed to 36 mL and 24 mL, 42 mL and 18 mL, 48 mL and 12 mL, and 54 mL and 6 mL. The filter cake was then further separated by using 60 mL of [a specific solution / method / process - the original text is missing here]. The pulp was washed with tBuOH and then centrifuged at 5000 rpm for 5 minutes to separate the filter cake. The filter cake was then dried in a vacuum drying oven at 50℃ to constant weight. After grinding and sieving through a 100-mesh iron sieve, it was finally vacuum dried at 50℃ for 48 hours and then protected with high-purity argon gas for later use.

[0058] Example 1

[0059] (1) Preparation of carbon dioxide-based elastomers

[0060] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 8.4 mg), co-catalyst (PPNCl, 6.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 2.5 mg), and epoxy monomers (allyl glycidyl ether, 0.5 mL; 1,2-epoxyhexane, 4.5 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (60 °C, 4 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0061] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 85% and 82%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content (carbonate content = carbonate segments in the copolymer / (carbonate segments + ether segments)) to be 83%, ether segment content to be 17%, and number-average molecular weight to be 113 kg / mol.

[0062] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0063] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0064] Example 2

[0065] (1) Preparation of carbon dioxide-based elastomers

[0066] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 11.2 mg), co-catalyst (PPNCl, 8.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 1.5 mg), and epoxy monomers (allyl glycidyl ether, 0.5 mL; 1,2-epoxyhexane, 4.5 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (65 °C, 5 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0067] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 88% and 83%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate the product, removing unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 87%, ether segment content 13%, number average molecular weight 106 kg / mol).

[0068] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0069] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0070] Example 3

[0071] (1) Preparation of carbon dioxide-based elastomers

[0072] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 11.2 mg), co-catalyst (PPNCl, 4.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 1.5 mg), and epoxy monomers (allyl glycidyl ether, 1.6 mL; 1,2-epoxyhexane, 3.4 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (75 °C, 4 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0073] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 99% and 99%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 81%, ether segment content 19%, number average molecular weight 66 kg / mol).

[0074] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0075] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0076] Example 4

[0077] (1) Preparation of carbon dioxide-based elastomers

[0078] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 8.4 mg), co-catalyst (PPNCl, 6.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 3.5 mg), and epoxy monomers (allyl glycidyl ether, 0.25 mL; 1,2-epoxyhexane, 4.75 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (55 °C, 4 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0079] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 82% and 79%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 86%, ether segment content 14%, number average molecular weight 102 kg / mol).

[0080] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0081] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0082] Example 5

[0083] (1) Preparation of carbon dioxide-based elastomers

[0084] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 8.4 mg), co-catalyst (PPNCl, 6.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 2.5 mg), and epoxy monomers (allyl glycidyl ether, 0.34 mL; 1,2-epoxybutane, 4.66 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and CO2 was added (60 °C, 4 MPa) to achieve the desired temperature and CO2 pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0085] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxybutane monomers with conversion rates of 94% and 89%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 87%, ether segment content 13%, number average molecular weight 89 kg / mol).

[0086] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0087] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0088] Example 6

[0089] (1) Preparation of carbon dioxide-based elastomers

[0090] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 8.4 mg), co-catalyst (PPNCl, 6.0 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 2.5 mg), and epoxy monomers (allyl glycidyl ether, 0.2 mL; 1,2-epoxyoctane, 4.8 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (60 °C, 3 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0091] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyoctane monomers with conversion rates of 86% and 81%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 83%, ether segment content 17%, number average molecular weight 96 kg / mol).

[0092] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0093] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0094] Example 7

[0095] (1) Preparation of carbon dioxide-based elastomers

[0096] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 10.0 mg), co-catalyst (PPNCl, 7.2 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 2.5 mg), and epoxy monomers (allyl glycidyl ether, 0.66 mL; 1,2-epoxybutane, 4.34 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (65 °C, 5 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 6 hours of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0097] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxybutane monomers with conversion rates of 84% and 80%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (85% carbonate segment content, 15% ether segment content, number average molecular weight 78 kg / mol).

[0098] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0099] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0100] Example 8

[0101] (1) Preparation of carbon dioxide-based elastomers

[0102] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 10.0 mg), co-catalyst (PPNCl, 7.2 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 1.5 mg), and epoxy monomers (allyl glycidyl ether, 0.4 mL; 1,2-epoxyoctane, 4.6 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (70 °C, 5 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 5 h of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0103] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyoctane monomers with conversion rates of 87% and 83%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40 °C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 75%, ether segment content 25%, number average molecular weight 74 kg / mol).

[0104] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0105] Carbon dioxide-based elastomer (3 g) and dicumyl peroxide (DCP) (0.0015 g) were dissolved in tetrahydrofuran (10 mL) and stirred at room temperature until completely dissolved. The solvent was then evaporated at room temperature. The resulting mixture was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. The samples were allowed to stand for 12 hours before tensile testing.

[0106] Example 9

[0107] (1) Preparation of carbon dioxide-based elastomers

[0108] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 10.5 mg), co-catalyst (PPNCl, 7.5 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 3.1 mg), and epoxy monomers (allyl glycidyl ether, 2.3 mL; 1,2-epoxyhexane, 22.7 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (70 °C, 4 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 12 h of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0109] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 85% and 80%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 83%, ether segment content 17%, number average molecular weight 127 kg / mol).

[0110] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0111] 50 g of carbon dioxide-based elastomer and 0.025 g of dicumyl peroxide (DCP) were mixed in an internal mixer at room temperature for 10 minutes to ensure uniform dispersion. Subsequently, the elastomer was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. After standing for 12 hours, a tensile test was performed.

[0112] Example 10

[0113] (1) Preparation of carbon dioxide-based elastomers

[0114] In an argon-atmospheric glove box, homogeneous catalyst (Al porphyrin, 10.5 mg), co-catalyst (PPNCl, 7.5 mg), heterogeneous catalyst (Zn-Co bimetallic cyanide, 3.1 mg), and epoxy monomers (allyl glycidyl ether, 1.3 mL; 1,2-epoxyhexane, 23.7 mL) were added to a pre-dried high-pressure reactor. The reactor was then heated and pressurized (60 °C, 5 MPa CO2) to achieve the desired temperature and carbon dioxide pressure. After 12 h of reaction, the reactor was cooled in an ice-water bath, and the CO2 pressure was slowly released.

[0115] A small portion of the crude product was analyzed by 1H NMR spectroscopy, yielding allyl glycidyl ether and 1,2-epoxyhexane monomers with conversion rates of 81% and 78%, respectively. The remaining product was dissolved in dichloromethane, and then excess methanol was added to precipitate and remove unreacted monomers and small molecule byproducts. The precipitated polymer was collected and dried under vacuum at 40°C for 48 hours to obtain a carbon dioxide-based elastomer. A small amount of the purified polymer was analyzed by 1H NMR and gel permeation chromatography (GPC) to determine its carbonate content and molecular weight (carbonate segment content 88%, ether segment content 12%, number average molecular weight 141 kg / mol).

[0116] (2) Preparation of cross-linked carbon dioxide-based elastomers

[0117] 50 g of carbon dioxide-based elastomer and 0.025 g of dicumyl peroxide (DCP) were mixed in an internal mixer at room temperature for 10 minutes to ensure uniform dispersion. Subsequently, the elastomer was crosslinked at 160 °C and 15 MPa for 0.5 hours to obtain the crosslinked carbon dioxide-based elastomer. After standing for 12 hours, a tensile test was performed.

[0118] Comparative Example 1: Preparation of carbon dioxide-based elastomers using only homogeneous catalysts

[0119] The preparation process in Example 1 was used, except that only Al porphyrin was used as a catalyst.

[0120] Test results showed that the reaction had almost no induction period, the conversion rate of epoxy monomers was 30%, the cyclic carbonate content in the product was 5%, the purified polymer had a carbonate segment content of 100%, no ether segments, a number-average molecular weight of 20 kg / mol, a molecular weight distribution index (PDI) of 1.24, and a glass transition temperature of -6 °C. The tensile strength of the prepared crosslinked carbon dioxide-based elastomer was only 0.5 MPa, and the elongation at break was 197%. Compared with Example 1, the catalytic efficiency, product molecular weight, and mechanical properties were significantly reduced.

[0121] Comparative Example 2: Preparation of carbon dioxide-based elastomers using only heterogeneous catalysts

[0122] The preparation process in Example 1 was used, except that only Zn-Co bimetallic cyanide was used as a catalyst.

[0123] Test results showed that the reaction induction period was >2 hours, the conversion rate of epoxy monomers was 99%, the cyclic carbonate content in the product was 3%, the purified polymer contained 65% carbonate segments and 35% ether segments, had a number-average molecular weight of 45 kg / mol, a molecular weight distribution index (PDI) of 2.65, and a glass transition temperature of -17°C. The tensile strength of the prepared crosslinked carbon dioxide-based elastomer was only 0.5 MPa, and the elongation at break was 467%. Compared with Example 1, the carbonate segment content, product molecular weight, and mechanical properties were significantly reduced.

[0124] Table 1 shows the performance test results of the carbon dioxide-based elastomers and cross-linked carbon dioxide-based elastomers prepared in Examples 1-10 and Comparative Examples 1-2.

[0125] Table 1

[0126]

[0127] As can be seen from the results in Table 1, compared with Comparative Examples 1-2, the carbon dioxide-based elastomers prepared in Examples 1-10 have higher number-average molecular weights and lower glass transition temperatures (Tg). g The reaction temperature ranges from +6 to -20°C, and the elastomers exhibit excellent mechanical properties. As can be seen from the comparison of the examples and comparative examples, this invention significantly reduces the induction period and improves the reaction efficiency through the synergistic effect of homogeneous and heterogeneous catalysts, while simultaneously increasing the molecular weight and mechanical properties of the carbon dioxide-based elastomers. This technology solves the problems of insufficient catalytic activity, reaction instability, and low molecular weight and poor mechanical properties of the products in the preparation of existing carbon dioxide-based elastomers. Due to its superior performance, this invention has broad application prospects in the field of carbon dioxide-based elastomer preparation.

Claims

1. A method for preparing a high molecular weight carbon dioxide-based elastomer, comprising: heating and polymerizing components comprising the carbon dioxide, an epoxy compound, and a composite catalyst, and then post-treating the high molecular weight carbon dioxide-based elastomer; wherein the composite catalyst comprises a homogeneous catalyst, a heterogeneous catalyst, and a cocatalyst, the homogeneous catalyst is an aluminum porphyrin, the heterogeneous catalyst is selected from Zn-Co double metal cyanide, and the cocatalyst is bis-(triphenylphosphine) ammonium chloride, the mass ratio of the homogeneous catalyst, the heterogeneous catalyst, and the cocatalyst is 1: (0.05-0.7): (0.2-1.5), the epoxy compound comprises a saturated epoxy compound and an unsaturated epoxy compound, the saturated epoxy compound is selected from at least one of C3-12 saturated alkyl epoxy compounds, the unsaturated epoxy compound is selected from at least one of unsaturated glycidyl ether compounds, and the molar ratio of the saturated epoxy compound and the unsaturated epoxy compound is 1: (0.01-0.5). 2.The method according to claim 1, wherein the saturated epoxy compound is selected from at least one of butylene oxide, hexylene oxide, and octylene oxide, and / or the unsaturated epoxy compound is selected from at least one of allyl glycidyl ether and glycidyl methacrylate, and / or the molar ratio of the saturated epoxy compound and the unsaturated epoxy compound is 1: (0.05-0.3), and / or the mass ratio of the homogeneous catalyst, the heterogeneous catalyst, and the cocatalyst is 1: (0.1-0.5): (0.3-0.9). 3.The method according to claim 1, wherein the amount of the heterogeneous catalyst in the composite catalyst is 0.002-0.12 wt% of the total amount of the epoxy compound, the amount of the homogeneous catalyst is 0.005-0.35 wt% of the total amount of the epoxy compound, and the amount of the cocatalyst is 0.005-0.25 wt% of the total amount of the epoxy compound, and / or the temperature of the polymerization reaction is 50-80 ℃, and / or the pressure of the polymerization reaction is 2-6 MPa, and / or the time of the polymerization reaction is 1-24 h. 4.The method according to claim 3, wherein the amount of the heterogeneous catalyst in the composite catalyst is 0.008-0.1 wt% of the total amount of the epoxy compound, and / or the amount of the homogeneous catalyst is 0.01-0.28 wt% of the total amount of the epoxy compound, and / or the amount of the cocatalyst is 0.01-0.20 wt% of the total amount of the epoxy compound, and / or the temperature of the polymerization reaction is 55-70 ℃, and / or the pressure of the polymerization reaction is 3-5 MPa, and / or the time of the polymerization reaction is 4-16 h. 5.The method according to claim 1, wherein the post-treatment comprises the steps of dissolving, precipitating, and drying. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6. The preparation method according to claim 5, wherein the dissolving solvent is selected from at least one of polar solvents; and / or, the precipitating solvent is selected from at least one of alcohols; and / or, the drying temperature is 25-60 °C.

7. The preparation method according to claim 6, wherein the dissolving solvent is selected from at least one of dichloromethane, tetrahydrofuran; and / or, the precipitating solvent is selected from at least one of methanol, ethanol; and / or, the drying temperature is 30-40 °C. The number average molecular weight of the high molecular weight carbon dioxide-based elastomer is 50-180 kg / mol. The number average molecular weight of the high molecular weight carbon dioxide-based elastomer is 80-150 kg / mol.

10. A preparation method of a crosslinked carbon dioxide-based elastomer, comprising the step of preparing the crosslinked carbon dioxide-based elastomer by initiating reaction of the high molecular weight carbon dioxide-based elastomer, wherein the high molecular weight carbon dioxide-based elastomer is prepared by the preparation method according to any one of claims 1-9. Specifically comprising the following steps: mixing the high molecular weight carbon dioxide-based elastomer and an initiator, and then heating to perform crosslinking reaction, thereby obtaining the crosslinked carbon dioxide-based elastomer; wherein the mixing is optionally performed in a solvent.

12. The preparation method according to claim 11, wherein the initiator is selected from at least one of peroxide initiators; and / or, the solvent is selected from at least one of tetrahydrofuran, dichloromethane, toluene; and / or, the amount of the initiator is 0.03-0.20 wt% of the amount of the high molecular weight carbon dioxide-based elastomer; and / or, the crosslinking reaction temperature is 120-210 °C; and / or, the crosslinking reaction pressure is 10-20 MPa.

8. The method of any one of claims 1 to 7, wherein the method further comprises the step of:

13. The preparation method according to claim 12, wherein the initiator is selected from at least one of dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-hexane; and / or, the amount of the initiator is 0.05-0.15 wt% of the amount of the high molecular weight carbon dioxide-based elastomer; and / or, the crosslinking reaction temperature is 150-180 °C; and / or, the crosslinking reaction pressure is 13-17 MPa. ​ 9. The production method according to claim 8, characterized by, ​ ​ 11. The method of claim 10, wherein the crosslinking of the carbon dioxide-based elastomer is performed at a temperature of from about 100°C to about 200°C. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images