A sulfur-containing cyclic olefin terpolymer, and a method for preparing and using the same

Abstract

The application discloses a sulfur-containing cyclic olefin terpolymer and a preparation method and application thereof. The sulfur-containing cyclic olefin terpolymer is obtained by polymerization of ethylene monomers, cyclic olefin monomers and sulfur-containing cyclic olefin monomers, wherein the ethylene units account for 40-75%, the cyclic olefin monomer units account for 15-50%, and the sulfur-containing cyclic olefin monomer units account for 1-20% in terms of the number of moles of the sulfur-containing cyclic olefin terpolymer. The application improves the refractive index of the material by introducing the sulfur-containing structure, and improves the thermal stability and transparency by using the rigid structure of the cyclic olefin, and can be used for optical materials.

Description

Technical Field

[0001] This application relates to the field of functionalized polyolefin technology, specifically to a sulfur-containing cyclic olefin terpolymer, its preparation method, and its application. Background Technology

[0002] Cyclic olefin copolymers possess high optical transparency, low birefringence, low hygroscopicity, and good heat resistance, and have been widely used in optical lenses, display devices, medical packaging, radomes, and other fields. While existing commercially available cyclic olefin copolymers exhibit good overall performance, their refractive indices are typically only 1.53–1.54, which is insufficient to meet the requirements of some high-refractive-index optical materials.

[0003] To improve the refractive index of cyclic olefin materials, existing technologies typically introduce highly polarizable structures such as sulfur atoms or large conjugated aromatic groups into the polymer molecule. Sulfur-containing cyclic olefin monomers can be used to prepare cyclic olefin copolymers with higher refractive indices through ring-opening metathesis polymerization and subsequent hydrogenation. However, this route usually requires the use of expensive and air / moisture-sensitive Grubbs series ruthenium catalysts, strict drying and deoxygenation before polymerization, and often requires hydrogenation saturation treatment after polymerization, making the process complex.

[0004] Furthermore, while sulfur-containing structures are beneficial for increasing the refractive index, sulfur atoms are susceptible to thermo-oxidative attack during high-temperature processing or in oxygen-rich environments, which may lead to a decline in material properties. If a metallocene-catalyzed coordination polymerization route is adopted, the sulfur atoms in the sulfur-containing monomers may coordinate with active metal centers such as titanium and zirconium, reducing catalytic activity. Therefore, obtaining sulfur-containing cyclic olefin terpolymers that possess high refractive index, saturated backbone, good thermal stability, and transparency remains a challenge. Summary of the Invention

[0005] This application addresses the technical problem that existing sulfur-containing cyclic olefin terpolymers struggle to simultaneously achieve high refractive index, thermal stability, and simplified processing, by providing a sulfur-containing cyclic olefin terpolymer, its preparation method, and its applications.

[0006] To achieve the above objectives, this application adopts the following technical solution: The first aspect of this application provides a sulfur-containing cyclic olefin terpolymer having the structure of Formula I:

[0007] Wherein, the ethylene unit shown as x accounts for 40% to 75% of the total molar number of all structural units in the sulfur-containing cyclic olefin terpolymer, the cyclic olefin unit shown as y accounts for 15% to 50% of the total molar number of all structural units, and the sulfur-containing cyclic olefin monomer unit shown as z accounts for 1% to 20% of the total molar number of all structural units; p is 0 or 1; q is 0 or 1; 20 ≤ n ≤ 5000.

[0008] Furthermore, the sulfur-containing cyclic olefin terpolymer is any one of the following formulas: .

[0009] Furthermore, the sulfur-containing cyclic olefin terpolymer has a weight-average molecular weight of 10-800 kDa; a glass transition temperature of 158-198 °C; and a 5wt% thermal weight loss temperature of 419-427 °C.

[0010] A second aspect of this application provides a method for preparing the sulfur-containing cyclic olefin terpolymer as described above, comprising: In an inert solvent, a cyclic olefin monomer, a sulfur-containing cyclic olefin monomer having the structure of formula II, and an ethylene monomer are polymerized under the action of a catalyst to obtain a sulfur-containing cyclic olefin terpolymer having the structure of formula I. Among them, sulfur-containing cyclic olefin monomers with the structure of formula II are shown below:

[0011] Where q is 0 or 1.

[0012] Furthermore, the cyclic olefin monomer is norbornene or tetracyclododecene.

[0013] Furthermore, the sulfur-containing cyclic olefin monomer having the structure of Formula II is selected from either Formula e or Formula f: .

[0014] Furthermore, the molar ratio of the catalyst to the cyclic olefin monomer is 1:(200~5000); the molar ratio of the catalyst to the sulfur-containing cyclic olefin monomer having the structure of Formula II is 1:(50~3000).

[0015] Furthermore, the catalyst is a metallocene catalyst, which is any one of the following: ethyl-bridged bis(indene) zirconium chloride catalyst, dimethylsilyl-bridged bis(indene) zirconium chloride catalyst, isopropylidene-bridged fluorene-zirconium chloride catalyst, diphenylmethylene-bridged fluorene-zirconium chloride catalyst, and dimethylsilyl-bridged restricted geometry titanium catalyst.

[0016] Furthermore, the polymerization reaction temperature is 30~120℃, and the polymerization reaction time is 5~240min.

[0017] The third aspect of this application provides the application of the sulfur-containing cyclic olefin terpolymer as described above, or the sulfur-containing cyclic olefin terpolymer prepared by the above preparation method, in optical materials.

[0018] Compared with the prior art, this application has the following beneficial effects: The sulfur-containing cyclic olefin terpolymer provided in this application comprises ethylene units, cyclic olefin units, and sulfur-containing cyclic olefin monomer units. This sulfur-containing cyclic olefin terpolymer possesses a combination of high refractive index, high transparency, and good thermal stability. The sulfur-containing cyclic olefin monomer units introduce sulfur with high polarizability into the polymer structure, thereby increasing the refractive index of the cyclic olefin copolymer and addressing the problem of low refractive index in conventional cyclic olefin copolymers. The cyclic olefin units provide a rigid cyclic structure, which is beneficial for improving the glass transition temperature and thermal stability of the polymer. The ethylene units facilitate the formation of a saturated main chain structure, maintaining good transparency and thermal stability. Simultaneously, the sulfur-containing groups are introduced into the polymer through the rigid cyclic olefin structure. The rigid three-dimensional ring structure provides a certain degree of spatial shielding for the sulfur-containing units, thereby improving the problems of easy oxidation, yellowing, and insufficient stability of sulfur-containing polymers.

[0019] The preparation method provided in this application employs a metallocene-catalyzed coordination polymerization route, enabling the ternary copolymerization of ethylene monomers, cyclic olefin monomers, and sulfur-containing cyclic olefin monomers with Formula II in an inert solvent, thus producing sulfur-containing cyclic olefin ternary copolymers with saturated backbones. Compared to the ring-opening metathesis polymerization route using Grubbs ruthenium catalysts, the preparation method of this application eliminates the need for pre-forming unsaturated backbones followed by hydrogenation saturation, simplifying the process and reducing preparation complexity. By selecting a metallocene catalyst with good stability and coordinating appropriate polymerization conditions, the adverse effects of sulfur atoms in the sulfur-containing monomers on the metal active centers can be reduced, maintaining good polymerization activity and achieving effective ternary copolymerization of sulfur-containing cyclic olefin monomers with ethylene and cyclic olefin monomers.

[0020] When the sulfur-containing cyclic olefin terpolymer provided in this application is used in optical materials, it can improve the refractive index of the material by utilizing the sulfur-containing structure, and improve the glass transition temperature and thermal stability of the material through the rigid structure of the cyclic olefin, while maintaining the good optical transparency of the cyclic olefin copolymer; it is suitable for use in optical materials such as optical lenses and display devices. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is the visible light transmittance curve of the sulfur-containing cyclic olefin terpolymer obtained in Example 3 of the present invention; Figure 2 This is the TGA curve spectrum of the sulfur-containing cyclic olefin terpolymer obtained in Example 4 of the present invention.

[0023] All chemical structural formulas in this patent application were drawn using InDraw Molecule Editor (integle.com). Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In one embodiment of this application, a sulfur-containing cyclic olefin terpolymer is provided, the sulfur-containing cyclic olefin terpolymer having the structure of Formula I:

[0026] The polymer chain of the sulfur-containing cyclic olefin terpolymer includes ethylene units, cyclic olefin units, and sulfur-containing cyclic olefin monomer units; wherein, the ethylene unit shown as x accounts for 40% to 75% of the total molar number of all structural units in the sulfur-containing cyclic olefin terpolymer, the cyclic olefin unit shown as y accounts for 15% to 50% of the total molar number of all structural units, and the sulfur-containing cyclic olefin monomer unit shown as z accounts for 1% to 20% of the total molar number of all structural units; p is 0 or 1, q is 0 or 1, and 20 ≤ n ≤ 5000.

[0027] In the above structure, the ethylene unit participates in the formation of the saturated main chain structure, which is beneficial for obtaining cyclic olefin copolymers with good thermal stability; the cyclic olefin unit introduces a rigid cyclic structure into the polymer molecule, which is beneficial for increasing the glass transition temperature of the material; the sulfur-containing cyclic olefin monomer unit introduces a sulfur-containing structure into the polymer, and sulfur has a high polarizability, which is beneficial for increasing the refractive index of the cyclic olefin copolymer. By controlling the combination of ethylene units, cyclic olefin units, and sulfur-containing cyclic olefin monomer units within the above molar content range, the refractive index of the material can be improved while maintaining the transparency and thermal stability of the cyclic olefin copolymer, making it suitable for the field of optical materials.

[0028] As a specific example, a sulfur-containing cyclic olefin terpolymer is any one of the following formulas: .

[0029] In some embodiments of this application, the weight-average molecular weight of the sulfur-containing cyclic olefin terpolymer is 10-800 kDa, and more specifically 20-200 kDa. A weight-average molecular weight within this range is advantageous for balancing polymer processability and material mechanical stability.

[0030] In one embodiment of this application, a method for preparing a sulfur-containing cyclic olefin terpolymer is provided, comprising: in an inert solvent, a cyclic olefin monomer, a sulfur-containing cyclic olefin monomer having a structure of formula II, and an ethylene monomer undergoing a polymerization reaction in the presence of a catalyst to obtain a sulfur-containing cyclic olefin terpolymer having a structure of formula I; Among them, sulfur-containing cyclic olefin monomers with the structure of formula II are shown below:

[0031] Where q is 0 or 1.

[0032] Coordination polymerization can directly produce polymers with saturated backbones, avoiding the unsaturated backbones and subsequent hydrogenation treatments typically involved in ring-opening metathesis polymerization. This helps reduce process complexity and improve the economic efficiency of preparation.

[0033] In some embodiments of this application, the cyclic olefin monomer is norbornene or tetracyclododecene. Both norbornene and tetracyclododecene can introduce rigid cyclic structures into the polymer chain during copolymerization, with tetracyclododecene having a larger rigid cyclic structure, which can further increase the glass transition temperature of the resulting cyclic olefin copolymer under the same polymerization system.

[0034] In some embodiments of this application, the sulfur-containing cyclic olefin monomer having the structure of Formula II is selected from either Formula e or Formula f: .

[0035] In a specific embodiment, the sulfur-containing structure in the sulfur-containing cyclic olefin monomer can improve the polarizability of the polymer, thereby increasing the refractive index of the resulting cyclic olefin copolymer; at the same time, the sulfur-containing group is attached to the cyclic olefin monomer, and the rigid three-dimensional ring structure can form a certain spatial shield for the sulfur-containing unit, which is beneficial to reducing the influence of oxygen and heat on sulfur atoms.

[0036] In some embodiments of this application, the molar ratio of the catalyst to the cyclic olefin monomer is 1:(200~5000), preferably 1:(500~2500); the molar ratio of the catalyst to the sulfur-containing cyclic olefin monomer having the structure of Formula II is 1:(50~3000), preferably 1:(200~2000). At these ratios, the catalyst provides suitable copolymerization activity, enabling the effective copolymerization of ethylene monomer, cyclic olefin monomer, and sulfur-containing cyclic olefin monomer under the action of the catalyst.

[0037] In some embodiments of this application, the inert solvent can be a straight-chain hydrocarbon compound, a cyclic hydrocarbon compound, or an aromatic hydrocarbon compound, further comprising a benzene compound, and even further comprising toluene. The inert solvent is used to disperse cyclic olefin monomers, sulfur-containing cyclic olefin monomers, and the catalyst, and to provide a reaction medium for the coordination polymerization of ethylene. When toluene is used as the inert solvent, it has good compatibility with cyclic olefin monomers and metallocene catalytic systems, which is beneficial for the stable progress of the polymerization reaction.

[0038] In some embodiments of this application, the catalyst is a metallocene catalyst. Metallocene catalysts exhibit excellent copolymerization catalytic activity, and high reactivity can be maintained by selecting appropriate catalyst structures and polymerization conditions. The metallocene catalyst can be any one of the following: ethyl-bridged bis(indene) zirconium chloride catalyst (Cat1), dimethylsilyl-bridged bis(indene) zirconium chloride catalyst (Cat2), isopropylidene-bridged fluorene-zirconium chloride catalyst (Cat3), diphenylmethylene-bridged fluorene-zirconium chloride catalyst (Cat4), and dimethylsilyl-bridged restricted geometry titanium catalyst (Cat5).

[0039] As a specific example, metallocene catalysts can be used in conjunction with a co-catalyst, which can be methylaluminoxane.

[0040] In some embodiments of this application, the reactor can be dried and the atmosphere purged before the polymerization reaction. For example, a glass pressure reactor connected to a gas pipeline is vacuum dried at 110°C for 1 h, repeatedly evacuated and purged with nitrogen three times, then purged with ethylene three times, and then the system temperature is adjusted to the polymerization reaction temperature. Drying and atmosphere purging can reduce the influence of air and moisture on the active sites of the metallocene catalyst and improve the stability of the coordination polymerization reaction.

[0041] In some embodiments of this application, the polymerization temperature is 30–120°C, and the polymerization time is 5–240 min. As examples, the polymerization temperature can be 30°C, 50°C, 65°C, 80°C, 90°C, or 120°C; the polymerization time can be 5 min, 10 min, 50 min, 100 min, 200 min, or 240 min. The polymerization temperature is used to regulate catalyst activity, monomer insertion rate, and copolymerization progress; the polymerization time is used to control the degree of polymer chain growth and the amount of product formed. The above temperature and time ranges are advantageous for ternary copolymerization of ethylene, cyclic olefins, and sulfur-containing cyclic olefin monomers under conditions involving sulfur-containing cyclic olefin monomers.

[0042] In some embodiments of this application, during the polymerization reaction, ethylene is introduced into the reaction system and the ethylene pressure is maintained at 1 to 5 atmospheres. As examples, the ethylene pressure can be maintained at 1 atmosphere, 3 atmospheres, or 5 atmospheres. The ethylene pressure is used to maintain the supply of ethylene monomers in the reaction system, enabling the ethylene units to continuously participate in the polymerization chain growth, thereby obtaining a sulfur-containing cyclic olefin terpolymer with the structure of Formula I.

[0043] In some embodiments of this application, after the polymerization reaction is completed, the polymerization reaction solution is post-treated. Specifically, the polymerization reaction solution is mixed with an ethanol solution of hydrochloric acid to terminate the polymerization chain growth; the volume fraction of the ethanol solution of hydrochloric acid can be 5% to 15%. Subsequently, the reaction product is subjected to solid-liquid separation, which can be achieved by filtration; the filtered product can be washed with ethanol, and the washing can be performed twice; after washing, it is vacuum dried at a temperature of 50 to 80°C for 16 to 24 hours. Through termination, filtration, washing, and drying, the solvent, residual monomers, co-catalysts, and other low-molecular-weight substances in the reaction system can be removed, yielding a sulfur-containing cyclic olefin terpolymer.

[0044] In some embodiments of this application, the resulting sulfur-containing cyclic olefin terpolymer can be used in optical materials. Because this polymer combines the low hygroscopicity, high transparency, and thermal stability of cyclic olefin copolymers, and improves the refractive index through sulfur-containing cyclic olefin monomers, it can be used in optical materials fields such as optical lenses and display devices where transparency, refractive index, and heat resistance are required.

[0045] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0047] Example 1 In this embodiment, firstly, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 110 °C for 1 h, and the process was repeated three times with vacuuming and nitrogen purging, followed by three purgings with ethylene. The system temperature was then set to 90 °C. Subsequently, under a nitrogen atmosphere, 2.5 mL of a 1 mol / L toluene-based co-catalyst solution of methylaluminoxane (MAO), 8 mL of toluene, 0.47 g of norbornene, and 0.76 g of sulfur-containing cyclic olefin monomer e were added to the reactor. Then, 5.0 μmol of diphenylmethylene-bridged zirconium dichloride catalyst (Cat 4) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Polymerization was carried out under rapid stirring at 500 rpm, with ethylene introduced and maintained at a pressure of 1 bar. After 10 min, the pressure reactor was emptied, 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried to constant weight in a vacuum oven to obtain 1.04 g of sulfur-containing cyclic olefin terpolymer.

[0048] According to the test results, the sulfur-containing cyclic olefin terpolymer obtained in this embodiment has a weight-average molecular weight of 128 kDa, a molecular weight distribution of 2.0, a glass transition temperature of 158°C, a 5 wt% thermal weight loss temperature of 415°C, a refractive index of 1.57, and a light transmittance of 91%.

[0049] Example 2 In this embodiment, firstly, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 110 °C for 1 h, and the process was repeated three times with vacuuming and nitrogen purging, followed by three purgings with ethylene. The system temperature was then set to 90 °C. Subsequently, under a nitrogen atmosphere, 2.5 mL of a 1 mol / L MAO co-catalyst solution prepared from toluene, 8 mL of toluene, 0.47 g of norbornene, and 1.09 g of sulfur-containing cyclic olefin monomer f were added to the reactor. Then, 5.0 μmol of Cat 4 (a diphenylmethylene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Polymerization was carried out under rapid stirring at 500 rpm, with ethylene introduced and maintained at a pressure of 1 bar. After 10 min, the pressure reactor was emptied, 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried to constant weight in a vacuum oven to obtain 1.71 g of sulfur-containing cyclic olefin terpolymer.

[0050] According to the test results, the sulfur-containing cyclic olefin terpolymer obtained in this embodiment has a weight-average molecular weight of 105 kDa, a molecular weight distribution of 2.1, a glass transition temperature of 167°C, a 5 wt% thermal weight loss temperature of 427°C, a refractive index of 1.56, and a light transmittance of 90%.

[0051] Example 3 In this embodiment, firstly, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 110 °C for 1 h, and the process was repeated three times with vacuuming and nitrogen purging, followed by three purgings with ethylene. The system temperature was then set to 90 °C. Subsequently, under an inert atmosphere, 2.5 mL of a 1 mol / L MAO cocatalyst solution prepared from toluene, 8 mL of toluene, 0.8 g of tetracyclododecene, and 0.76 g of sulfur-containing cyclic olefin monomer e were added to the reactor. Then, 5.0 μmol of Cat 4 (a diphenylmethylene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Polymerization was carried out under rapid stirring at 500 rpm, with ethylene introduced and maintained at a pressure of 1 bar. After 10 min, the pressure reactor was emptied, 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried to constant weight in a vacuum oven to obtain 1.98 g of sulfur-containing cyclic olefin terpolymer.

[0052] The sulfur-containing cyclic olefin terpolymer obtained in this embodiment has a weight-average molecular weight of 95 kDa, a molecular weight distribution of 2.1, a glass transition temperature of 189°C, a 5 wt% thermal loss temperature of 419°C, and a refractive index of 1.58, as tested. Figure 1 As shown in the figure, the transmittance of the sulfur-containing cyclic olefin terpolymer obtained in this embodiment is 91%.

[0053] Example 4 In this embodiment, firstly, a 75 mL glass pressure reactor connected to the gas pipeline was vacuum dried at 110 °C for 1 h, and the process was repeated three times with vacuuming and nitrogen purging, followed by three purgings with ethylene. The system temperature was then set to 90 °C. Subsequently, under an inert atmosphere, 2.5 mL of a 1 mol / L MAO cocatalyst solution prepared from toluene, 8 mL of toluene, 0.8 g of tetracyclododecene, and 1.09 g of sulfur-containing cyclic olefin monomer f were added to the reactor. Then, 5.0 μmol of Cat 4 (a diphenylmethylene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Polymerization was carried out under rapid stirring at 500 rpm, with ethylene introduced and maintained at a pressure of 1 bar. After 10 min, the pressure reactor was emptied, and 200 mL of hydrochloric acid-ethanol was added to quench the polymerization reaction. The polymer was filtered and dried to constant weight in a vacuum oven to obtain 2.11 g of a sulfur-containing cyclic olefin terpolymer.

[0054] The sulfur-containing cyclic olefin terpolymer obtained in this embodiment has a weight-average molecular weight of 85 kDa, a molecular weight distribution of 2.2, and a glass transition temperature of 198°C, as tested. Figure 2As shown in the figure, the 5wt% thermal weight loss temperature of the sulfur-containing cyclic olefin terpolymer in this embodiment is 422°C, the refractive index is 1.57, and the light transmittance is 90%.

[0055] Comparative Example 1 The main difference between this comparative example and Examples 1 and 2 is that no sulfur-containing cyclic olefin monomer was added; instead, 0.94 g of norbornene was used in the ethylene copolymerization. Specifically, a 75 mL glass pressure reactor connected to the gas pipeline was first vacuum-dried at 110 °C for 1 h, and then repeatedly evacuated and purged with nitrogen three times, followed by purging with ethylene three times. The system temperature was then set to 90 °C. Subsequently, under an inert atmosphere, 2.5 mL of a 1 mol / L MAO cocatalyst solution prepared from toluene, 8 mL of toluene, and 0.94 g of norbornene were added to the reactor. Then, 5.0 μmol of Cat 4 (a diphenylmethylene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Ethylene was introduced while stirring at 500 rpm and the ethylene pressure was maintained at 1 bar. After 10 min, the pressure reactor was emptied, 200 mL of hydrochloric acid ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried in a vacuum oven to constant weight to obtain 1.16 g of cyclic olefin copolymer.

[0056] The comparative example showed that the cyclic olefin copolymer had a weight-average molecular weight of 150 kDa, a molecular weight distribution of 2.1, a glass transition temperature of 132℃, a 5wt% thermal weight loss temperature of 429℃, a refractive index of 1.53, and a light transmittance of 90%.

[0057] Comparative Example 2 The main difference between this comparative example and Examples 3 and 4 is that no sulfur-containing cyclic olefin monomer was added; instead, 1.6 g of tetracyclododecene was used in the ethylene copolymerization. Specifically, a 75 mL glass pressure reactor connected to the gas pipeline was first vacuum-dried at 110 °C for 1 h, and then repeatedly evacuated and purged with nitrogen three times, followed by purging with ethylene three times. The system temperature was then set to 90 °C. Subsequently, under an inert atmosphere, 2.5 mL of a 1 mol / L MAO cocatalyst solution prepared from toluene, 8 mL of toluene, and 1.6 g of tetracyclododecene were added to the reactor. Then, 5.0 μmol of Cat 4 (a diphenylmethylene-bridged fluorene-containing zirconium dichloride catalyst) was dissolved in 2 mL of toluene and injected into the polymerization system using a syringe. Ethylene was introduced while stirring at 500 rpm and the ethylene pressure was maintained at 1 bar. After 10 min, the pressure reactor was emptied, 200 mL of hydrochloric acid ethanol was added to quench the polymerization reaction, the polymer was filtered, and dried in a vacuum oven to constant weight to obtain 1.71 g of cyclic olefin copolymer.

[0058] The comparative example showed that the cyclic olefin copolymer had a weight-average molecular weight of 140 kDa, a molecular weight distribution of 2.1, a glass transition temperature of 169℃, a 5wt% thermal weight loss temperature of 432℃, a refractive index of 1.54, and a light transmittance of 91%.

[0059] Test methods In this application, the glass transition temperature of the polymer was determined using differential scanning calorimetry (DSC). The glass transition temperature of the polymer was determined using a Mettler TOPEM DSC differential scanning calorimeter with a heating / cooling rate of 10 °C / min. Thermogravimetric analysis (TGA) was used to determine the thermogravimetric temperature of the polymer, and the TGA was performed using a Mettler-Toledo TGA2 instrument. The transmittance of the polymer was determined using a Shimadzu UV-3600 UV-Vis-NIR spectrophotometer with a wavelength range of 400–800 nm. The refractive index of the polymer was determined using an Abbe refractometer (DR-M4) at a test temperature of 25 °C and a test wavelength of 589 nm. The molecular weight and molecular weight distribution index of the polymer were determined using gel permeation chromatography (GPC) using a PL-GPC 220 GPC chromatograph with trichlorobenzene as the solvent at a test temperature of 150 °C and a flow rate of 1.0 mL / min.

[0060] Test Result Analysis The refractive indices of the sulfur-containing cyclic olefin terpolymers obtained in Examples 1-4 were 1.56-1.58, while the refractive indices of the sulfur-free cyclic olefin terpolymers obtained in Comparative Examples 1-2 were 1.53-1.54. This demonstrates that introducing a sulfur-containing cyclic olefin monomer with the structure of Formula II into the copolymerization system of ethylene and cyclic olefin monomers can increase the refractive index of the polymer. The light transmittance of the sulfur-containing cyclic olefin terpolymers obtained in Examples 1-4 was 90%-91%, maintaining high transparency, and the resulting materials are still suitable for use in optical materials.

[0061] In terms of heat resistance, the glass transition temperatures of the sulfur-containing cyclic olefin terpolymers obtained in Examples 1-4 were 158-198°C, while Examples 3 and 4, which used tetracyclic dodecene, had glass transition temperatures of 189°C and 198°C, respectively; this indicates that the type of cyclic olefin monomer can be used to control the glass transition temperature of the copolymer. The 5wt% thermal weight loss temperature of the sulfur-containing cyclic olefin terpolymers obtained in Examples 1-4 was 415-427°C, indicating that the obtained polymers have high thermal stability. Combined with the comparative examples, it can be seen that the introduction of sulfur-containing cyclic olefin monomers can increase the refractive index, while the cyclic olefin structure is beneficial for maintaining the glass transition temperature and heat resistance of the material.

[0062] The above embodiments and comparative examples illustrate that this application introduces a sulfur-containing structure into a cyclic olefin functional monomer and then copolymerizes it with ethylene, norbornene, or tetracyclododecene, resulting in the coexistence of sulfur-containing, rigid cyclic olefin, and ethylene structural units within the polymer chain. The sulfur-containing structure is beneficial for increasing the refractive index, the cyclic olefin structure is beneficial for increasing the glass transition temperature, and the ethylene structural units participate in forming the copolymer segments and maintaining the basic processing and transparency properties of the cyclic olefin copolymer material. Therefore, the resulting sulfur-containing cyclic olefin terpolymer can be used in the field of optical materials.

[0063] The above embodiments only illustrate several preferred implementations of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A sulfur-containing cyclic olefin terpolymer, characterized in that, It has the structure of Formula I: Wherein, the ethylene unit shown as x accounts for 40% to 75% of the total molar number of all structural units in the sulfur-containing cyclic olefin terpolymer, the cyclic olefin unit shown as y accounts for 15% to 50% of the total molar number of all structural units, and the sulfur-containing cyclic olefin monomer unit shown as z accounts for 1% to 20% of the total molar number of all structural units; p is 0 or 1; q is 0 or 1; 20 ≤ n ≤ 5000.

2. The sulfur-containing cyclic olefin terpolymer according to claim 1, characterized in that, The sulfur-containing cyclic olefin terpolymer is any one of the following formulas: 。 3. The sulfur-containing cyclic olefin terpolymer according to claim 1, characterized in that, The sulfur-containing cyclic olefin terpolymer has a weight-average molecular weight of 10-800 kDa, a glass transition temperature of 158-198 °C, and a 5wt% thermal weight loss temperature of 419-427 °C.

4. A method for preparing a sulfur-containing cyclic olefin terpolymer according to any one of claims 1-3, characterized in that, include: In an inert solvent, a cyclic olefin monomer, a sulfur-containing cyclic olefin monomer having the structure of formula II, and an ethylene monomer are polymerized under the action of a catalyst to obtain a sulfur-containing cyclic olefin terpolymer having the structure of formula I. Among them, sulfur-containing cyclic olefin monomers with the structure of formula II are shown below: Where q is 0 or 1.

5. The method for preparing the sulfur-containing cyclic olefin terpolymer according to claim 4, characterized in that, The cyclic olefin monomer is norbornene or tetracyclododecene.

6. The method for preparing the sulfur-containing cyclic olefin terpolymer according to claim 4, characterized in that, The sulfur-containing cyclic olefin monomer having the structure of formula II is selected from either formula e or formula f: 。 7. The method for preparing the sulfur-containing cyclic olefin terpolymer according to claim 4, characterized in that, The molar ratio of the catalyst to the cyclic olefin monomer is 1: (200~5000). The molar ratio of the catalyst to the sulfur-containing cyclic olefin monomer having the structure of Formula II is 1:(50~3000).

8. The method for preparing the sulfur-containing cyclic olefin terpolymer according to claim 4, characterized in that, The catalyst is a metallocene catalyst, which is any one of the following: ethyl-bridged bis(indene) zirconium chloride catalyst, dimethylsilyl-bridged bis(indene) zirconium chloride catalyst, isopropylidene-bridged fluorene-zirconium chloride catalyst, diphenylmethylene-bridged fluorene-zirconium chloride catalyst, and dimethylsilyl-bridged restricted geometry titanium catalyst.

9. The method for preparing the sulfur-containing cyclic olefin terpolymer according to claim 4, characterized in that, The polymerization reaction is carried out at a temperature of 30~120℃ for a duration of 5~240 min.

10. The application of a sulfur-containing cyclic olefin terpolymer according to any one of claims 1-3, or a sulfur-containing cyclic olefin terpolymer prepared by the preparation method according to any one of claims 4-9, in optical materials.

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