High-refractive-index bio-based optical resin as well as preparation method and application thereof

Abstract

The invention provides high-refractive-index bio-based optical resin and a preparation method and application thereof.The high-refractive-index bio-based optical resin comprises a structural unit selected from the formula (I), the high-refractive-index bio-based optical resin has the excellent performance of high refractive index, high thermal stability and the like, the highest refractive index can reach 1.716, and the high-refractive-index bio-based optical resin can be used as a high-refractive-index bio-based optical resin. The isosorbide polymer can meet the performance requirements of the isosorbide polymer as optical resin in optical components.

Description

Technical Field

[0001] The present invention belongs to the field of optical materials and relates to a high-refractive-index bio-based optical resin and a preparation method and application thereof. Background Art

[0002] There are abundant renewable biomass resources in nature. The development of a variety of biomass platform compounds using these as raw materials provides unlimited possibilities for the development and preparation of bio-based polymer materials with diverse performance, wide application, and environmental friendliness (Deng W, Feng Y, Fu J, et al. Catalytic conversion of lignocellulosic biomass into chemicals and fuels [J]. Green Energy & Environment, 2023, 8(1): 10-114.). Bio-based polymer materials have a huge market development space, and with the continuous reduction of petrochemical resources, bio-based polymer materials will become an important industry direction.

[0003] Isosorbide is a secondary dehydration product of biomass-derived D-glucitol. It is the only sugar diol that can be mass-produced industrially. Because its molecular structure contains two anti-connected tetrahydrofuran rings and hydroxyl groups located on the inner (C2) and outer (C3) surfaces, it is regarded as an important bio-based chemical raw material in the future, second only to polylactic acid. Isosorbide-based polycarbonate (PIC) materials are expected to replace traditional bisphenol A polycarbonate due to their advantages such as high light transmittance, high heat resistance, low yellowness, and green environmental protection. However, the lower refractive index (n) of PIC is not good. D=1.497), limiting its application in optical components such as high-refractive-index, lightweight optical lenses and optical film materials. Song et al. introduced 30% alicyclic or aromatic ring structures to the PIC backbone structure, raising the refractive index of PIC to 1.5394 (Song Z, Xu F, Wang H, et al. Design and synthesis of isosorbide-based copolycarbonates with high transparency and lowhygroscopicity for optical applications [J]. Journal of Applied Polymer Science, 2023: e54009.). However, Chu et al. only managed to increase the refractive index of PIC to a maximum of 1.5536 by introducing 30% sulfur-containing aromatic ring comonomers (Chu J, Wang H, Zhang Y, et al. Design and synthesis of gradient-refractive index isosorbide-based polycarbonates for optical uses [J]. Reactive and Functional Polymers, 2022, 170: 105145.).

[0004] As a biomass-based, environmentally friendly material, isosorbide-based polymers not only possess high transmittance but also excellent biocompatibility, making them a widely used optical resin. However, their relatively low refractive index cannot meet the optical performance requirements of some high-end electronic products or biomedical lenses. Therefore, the development of a high-refractive-index, bio-based optical resin material with an isosorbide backbone is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-refractive-index bio-based optical resin, its preparation method, and its application. The bio-based optical resin of the present invention combines excellent properties such as high refractive index and high thermal stability, with a refractive index of up to 1.716, meeting the performance requirements of isosorbide-based polymers as optical resins in optical components.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a high-refractive-index bio-based optical resin, comprising a structural unit selected from formula (I):

[0008]

[0009] Wherein the group —R1— is any one of the following aliphatic or aromatic groups:

[0010] (1) Aliphatic:

[0011] (2) Aromatic:

[0012] Specifically, the present invention introduces sulfur, alicyclic, or aromatic ring structures into the structural unit represented by formula (I), increasing the molar refractive index of the polymer repeating unit and, consequently, the optical refractive index of the bio-based optical resin. Furthermore, the high degree of unsaturation of the polyalicyclic or polyaromatic ring structures renders the molecular structure chemically extremely stable, resulting in excellent thermal stability for the bio-based optical resin material. In this manner, the bio-based optical resin of the present invention achieves both a high refractive index and high thermal stability.

[0013] Preferably, the high refractive index bio-based optical resin is an optical resin having a structure shown in any one of formulas (I-1) to (I-20), but is not limited to the following structural formula:

[0014]

[0015]

[0016]

[0017] In the present invention, the refractive index of the high refractive index bio-based optical resin can reach 1.533 to 1.716, such as 1.533, 1.538, 1.566, 1.570, 1.593, 1.600, 1.613, 1.625, 1.633, 1.655, 1.684, 1.693, 1.700, 1.705, 1.710, 1.712 or 1.716, etc., preferably The glass transition temperature of the high refractive index bio-based optical resin is 33°C to 180°C (e.g., 33°C, 40°C, 45°C, 50°C, 55°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C). Preferably, the weight average molecular weight of the high refractive index bio-based optical resin is 2.35×10 4 ~9.38×10 4 g / mol, for example 2.35×10 4g / mol, 2.40×10 4 g / mol, 2.45×10 4 g / mol, 2.50×10 4 g / mol, 2.55×10 4 g / mol, 2.60×10 4 g / mol, 2.65×10 4 g / mol, 2.73×10 4 g / mol, 2.78×10 4 g / mol, 3.0×10 4 g / mol, 3.50×10 4 g / mol, 4.0×10 4 g / mol, 4.50×10 4 g / mol, 5.0×10 4 g / mol, 5.5×10 4 g / mol, 6.0×10 4 g / mol, 7.0×10 4 g / mol, 7.55×10 4 g / mol, 7.83×10 4 g / mol, 8.0×10 4 g / mol, 8.57×10 4 g / mol, 9.0×10 4 g / mol, 9.38×10 4 g / mol.

[0018] In another aspect, the present invention provides a method for preparing the high refractive index bio-based optical resin as described above, the method comprising the following steps:

[0019] Isosorbide diacrylate and the dithiol compound undergo a polymerization reaction to obtain the high-refractive-index bio-based optical resin.

[0020] Preferably, the structure of the isosorbide diacrylate is:

[0021] Preferably, the structure of the dithiol compound is: HS-R1-SH.

[0022] In the present invention, the dithiol compound is any one of the following compounds:

[0023] (1) Aliphatic:

[0024] (2) Aromatic:

[0025] Preferably, the molar ratio of the dithiol compound to isosorbide diacrylate is 1:0.9-1.1, for example, 1:0.9, 1:0.95, 1:0.98, 1:1, 1:1.05, 1:1.08 or 1:1.1.

[0026] Preferably, the polymerization reaction is carried out in the presence of a catalyst.

[0027] Preferably, the catalyst is selected from an ionic liquid catalyst or an organic base catalyst.

[0028] Preferably, the cation in the ionic liquid catalyst is selected from any one of imidazolium cations, quaternary ammonium cations, quaternary phosphine cations, piperidine cations and pyridinium cations; and the anion is selected from any one of carboxylic acid anions, lactic acid anions, amino acid anions or amide anions.

[0029] Preferably, the organic base catalyst is at least one of triethylamine, tributylamine, pyridine, tetramethylguanidine, piperidine, piperazine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]decene-5-ene, 1,5-diazabicyclo[4.3.0]non-5-ene or 1,4-diazidebicyclo[2.2.2]octane.

[0030] Preferably, the molar ratio of the catalyst to the dithiol compound is 1×10 -5 -1.5×10 -1 :1, for example 1×10 -5 :1, 3×10 -5 :1,5×10 -5 :1, 8×10 -5 :1, 1×10 -4 :1, 3×10 -4 :1,5×10 -4 :1, 8×10 -4 :1, 1×10 -3 :1, 3×10 -3 :1,5×10 -3 :1, 8×10 -3 :1, 1×10 -2 :1, 3×10 -2 :1,5×10 -2 :1, 8×10 -2 :1, 1×10 -1 :1 or 1.5×10 -1:1.

[0031] In the present invention, the polymerization reaction is a click polymerization reaction.

[0032] Preferably, the polymerization reaction is carried out under nitrogen protection.

[0033] Preferably, the polymerization reaction temperature is 0 to 120°C (e.g., 0°C, 5°C, 8°C, 10°C, 30°C, 50°C, 80°C, 100°C or 120°C), the reaction pressure is normal pressure, and the reaction time is 1 to 24h (e.g., 1h, 3h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 22h or 24h).

[0034] Preferably, the polymerization reaction is carried out in solvent A, and the solvent A is selected from any one of dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, cyclohexanone, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropylene urea, and N-methylpyrrolidone, or a mixture of at least two thereof.

[0035] Preferably, the amount of solvent A is 2 to 32 times the total mass of isosorbide diacrylate and dithiol compound, for example, 2 times, 5 times, 8 times, 10 times, 13 times, 15 times, 18 times, 20 times, 22 times, 25 times, 28 times, 30 times or 32 times.

[0036] Preferably, after the polymerization reaction is completed, the reaction solution is added to solvent B for regeneration to precipitate a block product, which is then washed and purified to obtain the high refractive index bio-based optical resin.

[0037] Preferably, the solvent B is selected from any one of methanol, ethanol, isopropanol, ether or water, or a combination of at least two thereof.

[0038] Preferably, the amount of solvent B is 20 to 100 times that of solvent A, for example, 20 times, 25 times, 30 times, 35 times, 40 times, 45 times, 50 times, 55 times, 60 times, 65 times, 70 times, 75 times, 80 times, 85 times, 90 times, 95 times or 100 times.

[0039] The high-refractive-index bio-based optical resin obtained by the preparation method of the present invention can regulate the molecular weight of the product by changing the ratio of reactants and catalysts, so that the obtained high-refractive-index bio-based optical resin has excellent processing performance.

[0040] In the present invention, the following additives may be added to the high-refractive-index bio-based optical resin according to the performance requirements of different application scenarios: any one or a combination of at least two of antioxidants, plasticizers, anti-aging agents, heat stabilizers, fillers, dyes, light stabilizers, UV absorbers, flame retardants, antistatic agents, release agents, or antimicrobial agents. This can enhance the resin's antioxidant, UV resistance, antimicrobial, flame retardant, and stability properties. The amount of additives can be adjusted as needed.

[0041] In the present invention, the preparation method can easily obtain a bio-based optical resin with high refractive index, high thermal stability and adjustable molecular weight. The amount of catalyst used is small, the reaction conditions are mild, the reaction process does not cause environmental pollution, the product does not contain toxic substances, the process is simple, and it is easy to produce on a large scale. It is an efficient, green and environmentally friendly preparation process for bio-based optical resins.

[0042] In another aspect, the present invention provides a use of the high refractive index bio-based optical resin described above in optical films, optical components, electronic products, electrical equipment, packaging materials or medical devices.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The bio-based optical resin of the present invention exhibits excellent properties such as high refractive index and high thermal stability. By processing and using the bio-based optical resin, optical lenses or optical films with better performance can be prepared, which can be used in optical components, electronic products, electrical equipment, packaging materials or medical devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The H NMR spectra of the polymers prepared in Examples 1-5 are 1 H-NMR spectrum;

[0046] Figure 2 FT-IR images of the polymers prepared in Examples 1-5;

[0047] Figure 3 The molecular weight distribution GPC diagram of the polymers prepared in Examples 1-5;

[0048] Figure 4 Thermogravimetric (TGA) graphs of the polymers prepared in Examples 1-5;

[0049] Figure 5 The DSC diagrams of the polymers prepared in Examples 1-5 are shown. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] Example 1

[0052] The preparation steps of high refractive index bio-based optical resin are as follows:

[0053]

[0054] At room temperature, 0.02 mol of isosorbide diacrylate (ISDA) and 0.02 mol of the dithiol compound isosorbide bis(3-mercaptopropionate) (Dithiol-1) were dissolved in 40 mL of the organic solvent N,N-dimethylformamide (DMF). A catalyst, 0.5 mol% of the dithiol compound, imidazolyl lactate ionic liquid [Emim][Lac], was added under a nitrogen atmosphere and atmospheric pressure. The mixture was stirred at 25°C for 1 hour to undergo click polymerization. The mixture was then regenerated in 1000 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-1 was obtained.

[0055] Example 2

[0056] The preparation steps of high refractive index bio-based optical resin are as follows:

[0057]

[0058] At room temperature, 0.02 mol of isosorbide diacrylate (ISDA) and 0.02 mol of the dithiol compound biphenyl-4,4'-dithiol (Dithiol-2) were dissolved in 60 mL of the organic solvent N,N-dimethylacetamide (DMAc). Under a nitrogen atmosphere and atmospheric pressure, an organic base triethylamine (TEA) catalyst (5 mol% of the dithiol compound) was added. A click polymerization reaction was carried out at 60°C with stirring for 12 hours. The mixture was then added to 1000 mL of anti-solvent water for regeneration. After washing and purification, the bio-based optical resin material PITE-2 was obtained.

[0059] Example 3

[0060] The preparation steps of high refractive index bio-based optical resin are as follows:

[0061]

[0062] At room temperature, 0.03 mol of isosorbide diacrylate (ISDA) and 0.03 mol of the dithiol compound 4'4-dimercaptodiphenyl sulfide (Dithiol-3) were dissolved in 30 mL of the organic solvent N,N-dimethylformamide (DMF). An ionic liquid [Bmim][Ac] catalyst (0.5 mol% of the dithiol compound) was added under a nitrogen atmosphere and atmospheric pressure. The mixture was stirred at 80°C for 6 hours via click polymerization, then regenerated in 1500 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-3 was obtained.

[0063] Example 4

[0064] The preparation steps of high refractive index bio-based optical resin are as follows:

[0065]

[0066] At room temperature, 0.03 mol of isosorbide diacrylate (ISDA) and 0.03 mol of the dithiol compound 1,5-dimercaptonaphthalene (Dithiol-4) were dissolved in 60 mL of the organic solvent N-methylpyrrolidone (NMP). An ionic liquid [DBU][Lac] catalyst (10 mol% of the dithiol compound) was added under a nitrogen atmosphere and atmospheric pressure. The mixture was stirred at 60°C for 1 hour via click polymerization, and then regenerated in 1800 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-4 was obtained.

[0067] Example 5

[0068] The preparation steps of high refractive index bio-based optical resin are as follows:

[0069]

[0070] At room temperature, 0.03 mol of isosorbide diacrylate (ISDA) and 0.03 mol of the dithiol compound 9,9-bis(6-mercapto-2-naphthol)fluorene (Dithiol-5) were dissolved in 80 mL of the organic solvent N,N-dimethylacetamide (DMAc). Under a nitrogen atmosphere and atmospheric pressure, an organic base 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) catalyst (5 mol% of the dithiol compound) was added. The mixture was stirred at 120°C for 24 hours via click polymerization, and then regenerated in 2400 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-5 was obtained.

[0071] Example 6

[0072] The preparation steps of high refractive index bio-based optical resin are as follows:

[0073]

[0074] At room temperature, 0.05 mol of isosorbide diacrylate (ISDA) and 0.05 mol of the dithiol compound 2,5-dimethylmercapto-1,4-dithiane (Dithiol-6) were dissolved in 50 mL of tetrahydrofuran (THF), an organic solvent. Under a nitrogen atmosphere and at normal pressure, an organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalyst (0.5 mol% of the dithiol compound) was added. The mixture was stirred at 60°C for 3 hours through click polymerization, and then regenerated in 500 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-6 was obtained.

[0075] Example 7

[0076] The preparation steps of high refractive index bio-based optical resin are as follows:

[0077]

[0078] At room temperature, 0.01 mol of isosorbide diacrylate (ISDA) and 0.01 mol of dithiol compound 2,5-dimercapto-1,4-dithiane (Dithiol-7) were dissolved in 20 mL of organic solvent chloroform (CHCl3), and ionic liquid tetraethylammonium lactate [N 2222 [Lac] catalyst, the catalyst amount is 2 mol% of the amount of dithiol compound, and the reaction is stirred at 80° C. for 3 h by click polymerization, and then added to 1000 mL of anti-solvent ether for regeneration, and washed and purified to obtain the bio-based optical resin material PITE-7.

[0079] Example 8

[0080] The preparation steps of high refractive index bio-based optical resin are as follows:

[0081]

[0082] At room temperature, 0.03 mol of isosorbide diacrylate (ISDA) and 0.03 mol of the dithiol compound Dithiol-8 were dissolved in 60 mL of an organic mixed solvent (DMF:NMP=1:1). [Emim][Lac] catalyst (15 mol% of the dithiol compound) was added under a nitrogen atmosphere and atmospheric pressure. A click polymerization reaction was carried out at 70°C with stirring for 12 hours. The mixture was then regenerated in 1800 mL of the anti-solvent methanol. After washing and purification, the bio-based optical resin material PITE-8 was obtained.

[0083] Example 9

[0084] The preparation steps of high refractive index bio-based optical resin are as follows:

[0085]

[0086] At room temperature, 0.02 mol of isosorbide diacrylate (ISDA) and 0.02 mol of dithiol compound 2,2'-binaphthyl-9,9'-dithiol (Dithiol-9) were dissolved in 40 mL of organic solvent N,N-dimethylacetamide (DMAc), and tetrabutyl lactic acid phosphonium ionic liquid [P 4444 [Lac] catalyst, the catalyst amount is 10 mol% of the amount of dithiol compound, and the reaction is stirred at 80° C. for 6 h by click polymerization, and then added to 1500 mL of anti-solvent methanol for regeneration, and washed and purified to obtain the bio-based optical resin material PITE-9.

[0087] Comparative Example 1

[0088] The same operation as in Example 1 was carried out except that 0.02 mol of the dithiol compound ethanedithiol was used as a raw material to obtain a bio-based resin material PITE-10.

[0089] Comparative Example 2

[0090] The same operation as in Example 3 was carried out except that no catalyst was used.

[0091] The deuterated chloroform nuclear magnetic resonance (NMR) spectrum of the resins obtained in Examples 1-5 was tested using a 600 MHz nuclear magnetic resonance (NMR) spectrometer. The test results are shown in Table 1. Figure 1 As shown, each peak was attributed, and it can be seen that Examples 1-5 successfully prepared the resin.

[0092] The resins prepared in Examples 1-5 were characterized using an infrared spectrometer (Thermo Nicolet 380 Spectrophotometer). The results are as follows: Figure 2 As shown by Figure 2 It can be seen that at the wave number of 1740 cm -1 Obvious carbonyl C=O stretching vibration peaks appear at all locations, and characteristic peaks of other aromatic structures and alkyl chains can further confirm the structural correctness of the resin.

[0093] The thermal and physical properties of the bio-based optical resin materials provided in Examples 1 to 9 and Comparative Examples 1 to 2 were tested, including the glass transition temperature T g , 5% thermal decomposition temperature T d-5％ , weight average molecular weight M w, refractive index, Abbe number.

[0094] 1. The samples used for performance evaluation were prepared by the following method:

[0095] (a) Film: 1 g of the obtained bio-based optical resin was dissolved in 10 mL of dichloromethane and cast on a glass dish. After fully drying at room temperature, a film with a thickness of about 100 μm was prepared.

[0096] 2. Evaluation test methods are as follows:

[0097] (a) Weight average molecular weight (M w ):A PL-GPC 50 gel permeation chromatograph manufactured by Agilent Technologies was used, N,N-dimethylformamide (DMF) was used as the developing solvent, and a standard curve was prepared using monodisperse polystyrene of known molecular weight as the standard sample. Based on this standard curve, M was obtained from the GPC retention time. w .

[0098] (b) Refractive index (n D )

[0099] The refractive index of the film produced by the method (a) at 25° C. was measured using a DR-M4 Abbe refractometer manufactured by ATAGO at a wavelength of 589 nm.

[0100] (c) Abbe number (V D )

[0101] According to the refractive index test method in (b), the refractive index at 25°C and wavelengths of 486nm, 589nm, and 656nm is tested respectively. The formula V D =(n D -1) / (n F -n C ) is calculated, where n D is the refractive index at a wavelength of 589 nm, n F is the refractive index at a wavelength of 656 nm, n C is the refractive index at a wavelength of 486 nm.

[0102] (d) Glass transition temperature T g , 5% thermal decomposition temperature T d-5％

[0103] The prepared bio-based optical resin T g and T d-5％ The temperature was raised to 600°C for testing using a METTLER TOLEDO differential scanning calorimeter (TGA / DSC 3+) under a nitrogen (N2) atmosphere at a heating rate of 10°C / min.

[0104] Figure 3 GPC diagram of the molecular weight distribution of the polymers (i.e., resins) obtained in Examples 1-5; Figure 4 Thermogravimetric TGA graphs of the polymers prepared in Examples 1-5; Figure 5 The DSC diagrams of the polymers prepared in Examples 1-5 are shown.

[0105] The test data are shown in Table 1, wherein Comparative Example 2 cannot form a film and obtain optical data due to the low molecular weight.

[0106] Table 1

[0107]

[0108] The test results in Table 1 show that the bio-based optical resin with specific repeating units provided by the present invention has a higher yield than the isosorbide-based polycarbonate (n D =1.497), the refractive index is significantly improved. The refractive index of the bio-based optical resin is as high as 1.533-1.716, the Abbe number is 19-58, there is no obvious birefringence phenomenon, and it has excellent optical properties.

[0109] The applicant states that while the above-described embodiments illustrate the high-refractive-index bio-based optical resin, its preparation method, and its application, the present invention is not limited to these embodiments. This does not necessarily mean that the present invention must rely on these embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A high refractive index bio-based optical resin, characterized in that: The high refractive index bio-based optical resin comprises a structural unit selected from the group consisting of: Wherein the group —R1— is any one of the following aliphatic or aromatic groups:

2. The high refractive index bio-based optical resin according to claim 1, characterized in that: The high refractive index bio-based optical resin is an optical resin having a structure shown in any one of formulas (I-1) to (I-20):

3. The high refractive index bio-based optical resin according to claim 1 or 2, characterized in that: The refractive index of the high-refractive-index bio-based optical resin can reach 1.533 to 1.

716.

4. The high refractive index bio-based optical resin according to any one of claims 1 to 3, characterized in that: The glass transition temperature of the high refractive index bio-based optical resin is 33° C. to 180° C.; Preferably, the weight average molecular weight of the high refractive index bio-based optical resin is 2.35×10 4 ~9.38×10 4 g / mol.

5. The method for preparing a high refractive index bio-based optical resin according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: Isosorbide diacrylate and the dithiol compound undergo a polymerization reaction to obtain the high-refractive-index bio-based optical resin.

6. The preparation method according to claim 5, characterized in that The structure of the isosorbide diacrylate is: Preferably, the structure of the dithiol compound is: HS-R1-SH.

7. The preparation method according to claim 5 or 6, characterized in that: The dithiol compound is any one of the following compounds:

8. The preparation method according to any one of claims 5 to 7, characterized in that The molar ratio of the dithiol compound to isosorbide diacrylate is 1:0.9-1.1; Preferably, the polymerization reaction is carried out in the presence of a catalyst; Preferably, the catalyst is selected from an ionic liquid catalyst or an organic base catalyst; Preferably, the cation in the ionic liquid catalyst is selected from any one of imidazolium cations, quaternary ammonium cations, quaternary phosphine cations, piperidine cations and pyridinium cations; and the anion is selected from any one of carboxylic acid anions, lactic acid anions, amino acid anions or amide anions. Preferably, the organic base catalyst is at least one of triethylamine, tributylamine, pyridine, tetramethylguanidine, piperidine, piperazine, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]decene-5-ene, 1,5-diazabicyclo[4.3.0]non-5-ene or 1,4-diazidebicyclo[2.2.2]octane; Preferably, the molar ratio of the catalyst to the dithiol compound is 1×10 -5 -1.5×10 -1 :1; Preferably, the polymerization reaction is carried out under nitrogen protection; Preferably, the polymerization reaction temperature is 0 to 120° C., the reaction pressure is normal pressure, and the reaction time is 1 to 24 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that The polymerization reaction is carried out in solvent A, wherein the solvent A is selected from any one of dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, cyclohexanone, dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropylene urea, and N-methylpyrrolidone, or a mixture of at least two thereof; Preferably, the amount of solvent A is 2 to 32 times the total mass of isosorbide diacrylate and dithiol compound; Preferably, after the polymerization reaction is completed, the reaction solution is added to solvent B for regeneration to precipitate a bulk product, which is then washed and purified to obtain the high refractive index bio-based optical resin; Preferably, the solvent B is selected from any one or a combination of at least two of methanol, ethanol, isopropanol, diethyl ether or water; Preferably, the amount of solvent B used is 20 to 100 times the amount of solvent A used.

10. Use of the high-refractive-index bio-based optical resin according to any one of claims 1 to 4 in optical films, optical components, electronic products, electrical equipment, packaging materials or medical devices.

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