Fluorine-containing polyester compound with low refractive index as well as preparation method and application of fluorine-containing polyester compound

Abstract

The invention discloses a fluorine-containing polyester compound with a low refractive index and a preparation method and application thereof, and belongs to the technical field of high polymer chemistry, a binary fluorine-containing alkyne compound and a binary fluorine-containing alcohol compound are used as monomers, and the fluorine-containing polyester compound can be prepared through a polymerization reaction. And further introducing a polyol compound into the reaction system, and branching the space structure of the fluorine-containing polyester compound to obtain the fluorine-containing polyester compound with the branched structure. The fluorine-containing polyester compound and the fluorine-containing polyester compound with the branched structure are low in refractive index, the preparation method is simple and mild in condition, the fluorine-containing polyester compound shows wide application prospects in the fields of optical devices and display, and the fluorine-containing polyester compound also has excellent thermal stability and good solubility and is convenient to process and form.

Description

Technical Field

[0001] This invention belongs to the field of polymer chemistry technology, specifically relating to low refractive index fluorinated polyester compounds, their preparation methods, and applications. Background Technology

[0002] Low refractive index polymers are a class of functional materials with important application prospects in the optoelectronic field. Their refractive index (...) n Typically below 1.50, these materials possess excellent optical properties such as high light transmittance and low dispersion. They exhibit broad application potential in various fields, including optical lenses, virtual reality / augmented reality technologies, fiber optic cladding materials, and anti-reflective films.

[0003] High refractive index polymers (typically) n While polymers with a refractive index (>1.60) possess strong refractive power, their inherent high surface reflectivity and significant dispersion degrade image quality. Therefore, low refractive index materials are often introduced in optical design to compensate for the shortcomings of low refractive index materials with their high transmittance and low dispersion, thereby achieving superior imaging performance. This highlights the practical necessity of developing novel low refractive index polymers.

[0004] In recent years, researchers have been dedicated to developing polymer materials with low refractive index. Based on the Lorentz-Lorenz formula, the main strategies for reducing the refractive index of polymers can be divided into two categories: one is to reduce the molar refractive index of the groups in the repeating unit of the polymer, such as introducing low molar refractive index groups into the molecular chain; the other is to increase the molar volume of the repeating unit, such as by controlling the spatial structure of the polymer and reducing the packing density, and synthesizing polymers with branched or brush-like structures.

[0005] For example, Chinese patent document CN119241814A discloses a method for preparing an ultra-low refractive index, high-transparency cyclic olefin copolymer. This invention, under the conditions of a Grubbs catalyst and organic solvent, uses cyclic olefin monomers and fluorinated cyclic olefin monomers to prepare an unsaturated fluorinated cyclic olefin copolymer through a ring-opening metathesis polymerization reaction. The unsaturated fluorinated cyclic olefin copolymer is then hydrogenated with a hydrogen source to obtain a fluorinated cyclic olefin copolymer with an ultra-low refractive index. Chinese patent document CN119490637A discloses a synthesis process for a low-refractive-index polysiloxane resin. This synthesis process uses aminopropyl double-terminated polydimethylsiloxane and isocyanate as the main raw materials. The amino double-terminated polydimethylsiloxane and isocyanate are fed in a molar ratio of 1:(1-2) and reacted under an inert gas atmosphere to obtain a low-refractive-index polysiloxane resin.

[0006] Although relevant patents have made progress in developing low refractive index polymers, the types still need to be further expanded. To this end, designing and synthesizing new low refractive index polymers, and systematically studying the internal relationship between the structure and performance, has important significance for deepening the theoretical understanding and promoting the technological innovation of optoelectronic materials. SUMMARY

[0007] The application provides a fluorine-containing polyester compound and a branched fluorine-containing polyester compound, which have low refractive indexes, simple and mild preparation methods, good solution processing performance, good thermal stability, and good application prospects in the field of optics.

[0008] The specific technical solutions are as follows: A fluorine-containing polyester compound has the following structural formula: ; (I); In formula (I), R 1 and R 2 are each independently a fluorine-substituted alkylene group with a carbon number of C3-C22; the polymerization degree n is in the range of 10-500.

[0009] Further, in formula (I), the structural general formula of R 1 and R 2 is preferably , * represents a connection position, wherein m is an integer of 1-20, and R 1 and R 2 may be the same or different.

[0010] The application further provides a branched fluorine-containing polyester compound, which has the following structural formula: ; (II); ; (III); In formula (II) and formula (III), R 1 and R 2 are defined as in formula (I), R 3 is a triol residue, and R 4 is a tetrol residue, represents a repeated branched structure; the branched fluorine-containing polyester compound has a weight average molecular weight of 10-500 kDa.

[0011] Further, the fluorine-containing polyester compound and the branched fluorine-containing polyester compound provided by the application have low refractive indexes, and the refractive indexes are each less than 1.5.

[0012] The application takes binary fluorine-containing acetylenic compound and binary fluorine-containing alcoholic compound as monomers, and prepares target fluorine-containing polyester compound through high-efficiency polymerization reaction, and the preparation method is simple to operate, and the refractive index of the obtained fluorine-containing polyester compound is significantly lower than that of conventional materials, and the refractive index is further reduced after introducing polyhydric alcohol compound into the reaction system to branch the space structure of the fluorine-containing polyester compound, and the refractive index of the branched fluorine-containing polyester compound is lower.

[0013] The preparation method of the fluorine-containing polyester compound comprises the following steps: under the action of an alkali catalyst, binary fluorine-containing acetylenic compound and binary fluorine-containing alcoholic compound are subjected to polymerization reaction in an organic solvent under air atmosphere, and after the reaction is completed, the fluorine-containing polyester compound is obtained through post-processing.

[0014] The preparation method of the branched fluorine-containing polyester compound comprises the following steps: under the action of an alkali catalyst, binary fluorine-containing acetylenic compound, binary fluorine-containing alcoholic compound and polyhydric alcohol are subjected to polymerization reaction in an organic solvent under air atmosphere, and after the reaction is completed, the branched fluorine-containing polyester compound is obtained through post-processing; the polyhydric alcohol is trihydric alcohol or tetrahydric alcohol.

[0015] In the preparation process of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound, the structural formula of the binary fluorine-containing acetylenic compound is , the structural formula of the binary fluorine-containing alcoholic compound is , R 1 and R 2 are defined as the same as formula (I).

[0016] Further, the binary fluorine-containing acetylenic compound is obtained by reacting and propargyl acid.

[0017] Further, in the preparation process of the fluorine-containing polyester compound, the molar ratio of the binary fluorine-containing acetylenic compound and the binary fluorine-containing alcoholic compound is 1:0.6-1.5; in the preparation process of the branched fluorine-containing polyester compound, the molar ratio of the binary fluorine-containing acetylenic compound, the binary fluorine-containing alcoholic compound and the polyhydric alcohol is 1:0.6-1.5:0.001-0.1.

[0018] Further, in the preparation process of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound, the concentration of the binary fluorine-containing acetylenic compound in the organic solvent is 0.01-5 mol L -1; the temperature of the polymerization reaction is 0-100 °C, and the time of the polymerization reaction is 1-120 min.

[0019] Preferably, in the preparation of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound, the base catalyst is at least one of 1,4-diazidobicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, triethylamine, diisopropylethylamine, pyridine, 4-dimethylaminopyridine, sodium methoxide, sodium ethoxide, potassium tert-butoxide, potassium carbonate, and cesium carbonate; the base catalyst is further preferably 1,4-diazidobicyclo[2.2.2]octane; and the amount of the base catalyst is 1-200% of the molar amount of the binary fluorine-containing alkyne compound.

[0020] Preferably, in the preparation of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound, the organic solvent is at least one of tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide; and the organic solvent is further preferably tetrahydrofuran, so that the fluorine-containing polyester compound obtained has a higher molecular weight and better solubility.

[0021] Preferably, in the preparation of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound, the post-treatment method is: adding the polymer solution obtained through the polymerization reaction into a precipitant to perform precipitation, filtering to obtain a precipitate, washing the precipitate, collecting the precipitate, and drying to constant weight.

[0022] Further preferably, the precipitant is petroleum ether, n-hexane, methanol, ethanol, or diethyl ether.

[0023] Further preferably, the drying mode is vacuum drying, and the temperature is 25-80 °C.

[0024] The application also provides the application of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound in the optical field, and the application is specifically to prepare low-refractive-index optical lenses, anti-reflection coatings, and other refractive materials.

[0025] Compared with the prior art, the application has the following beneficial effects: (1) The fluorine-containing polyester compound and the branched fluorine-containing polyester compound provided by the application both have a low refractive index (nD20) ≤ 1.47). n 589.3 nm ≤ 1.47).

[0026] (2) The preparation method of the fluorine-containing polyester compound and the branched fluorine-containing polyester compound in the application is simple and easy to operate, raw materials are easy to obtain, and large-scale production is facilitated.

[0027] (3) The fluorine-containing polyester compound and the branched fluorine-containing polyester compound in the present application can be prepared without inert gas protection, and the reaction can be carried out at room temperature in the air, the reaction conditions are mild, the reaction efficiency is high, and a polymer with a high molecular weight can be obtained in 5 minutes, and the atomic utilization efficiency is high during the polymerization process, and no by-products are generated.

[0028] (4) The fluorine-containing polyester compound and the branched fluorine-containing polyester compound in the present application have good thermal stability and solubility, good processability, and the molecular structure has dynamic ester bonds, enol ether bonds and double bonds, and has a certain degradability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the fluorine-containing polyester compound P1 prepared in Example 1 and the corresponding monomers and model compounds in DMSO-6 is shown in Figure 1; wherein A is the spectrum of monomer M1, B is the spectrum of monomer M2, C is the spectrum of the model small molecule enol ether, and D is the spectrum of the fluorine-containing polyester compound P1, and the numerical markers represent the peak positions. d

[0030] The nuclear magnetic resonance hydrogen spectrum of the fluorine-containing polyester compound P1 prepared in Example 1 and the corresponding monomers and model compounds in DMSO-6 is shown in Figure 1; wherein A is the spectrum of monomer M1, B is the spectrum of monomer M2, C is the spectrum of the model small molecule enol ether, and D is the spectrum of the fluorine-containing polyester compound P1, and the numerical markers represent the peak positions. Figure 2 d The nuclear magnetic resonance hydrogen spectrum of the fluorine-containing polyester compound P1 prepared in Example 1 and the corresponding monomers and model compounds in DMSO-6 is shown in Figure 1; wherein A is the spectrum of monomer M1, B is the spectrum of monomer M2, C is the spectrum of the model small molecule enol ether, and D is the spectrum of the fluorine-containing polyester compound P1, and the numerical markers represent the peak positions.

[0031] Figure 3 d The nuclear magnetic resonance hydrogen spectrum of the fluorine-containing polyester compound P1 prepared in Example 1 and the corresponding monomers and model compounds in DMSO-6 is shown in Figure 1; wherein A is the spectrum of monomer M1, B is the spectrum of monomer M2, C is the spectrum of the model small molecule enol ether, and D is the spectrum of the fluorine-containing polyester compound P1, and the numerical markers represent the peak positions.

[0032] Figure 4 The thermal gravimetric curve of the fluorine-containing polyester compound P1 prepared in Example 1 is shown in Figure 4.

[0033] Figure 5 The refractive index curve of the fluorine-containing polyester compound P1 prepared in Example 1 is shown in Figure 5.

[0034] Figure 6 The refractive index curve of the fluorine-containing polyester compound P16 prepared in Example 16 and the branched fluorine-containing polyester compound P17 prepared in Example 17 is shown in Figure 6. DETAILED DESCRIPTION

[0035] ​​In order to make the objectives, characteristics and advantages of the present application more obvious and easy to understand, the following will be described in detail through specific embodiments. In the following description, a large number of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited by the specific embodiments disclosed below. The technical features in each embodiment of the present application can be combined accordingly without conflict.

[0036] The operation methods not specified in the following examples are generally carried out according to the conventional conditions or the conditions recommended by the manufacturers. The contents not described in detail in the specification belong to the prior art known to those skilled in the art. The experimental materials used in the following examples can be purchased from the conventional biochemical reagent companies, unless otherwise specified.

[0037] Example 1 The specific process of the synthesis method of the monomer M1 (a binary fluorine-containing alkyne compound) in this embodiment is as follows: 2,2,3,3-tetrafluoro-1,4-butanediol (1.62 g, 10.0 mmol), N,N'-dicyclohexylcarbodiimide (6.19 g, 30.0 mmol), 4-dimethylaminopyridine (0.367 g, 3.00 mmol), p-toluenesulfonic acid (0.689 g, 4.00 mmol) and a stirring rod are added to a 100 mL round-bottom flask, and then 30.0 mL of anhydrous dichloromethane is added. Propargyl acid (2.10 g, 1.85 mL, 30.0 mmol) is dissolved in 30.0 mL of anhydrous dichloromethane, and is slowly added dropwise under ice bath. After the dropwise addition is completed, it is stirred at room temperature for 4 h. After the reaction is completed, it is filtered, and the product monomer M1 is separated by column chromatography with petroleum ether and dichloromethane as eluents, with a yield of 51%, and its structure is as shown below:

[0038] The monomer M2 (a binary fluorine-containing alcohol compound) is 2,2,3,3-tetrafluoro-1,4-butanediol, which can be purchased from the market.

[0039] In this embodiment, the preparation method of the fluorine-containing polyester compound P1 is as follows: (1) In a 25 mL polymerization tube, the monomer M1 (0.107 g, 0.400 mmol) and the monomer M2 (0.0648 g, 0.400 mmol) are dissolved in 0.80 mL of tetrahydrofuran, and then 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1); the polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min; (2) The polymer solution of step (1) was added dropwise to n-hexane under stirring, followed by filtration and vacuum drying to constant weight to obtain a fluorine-containing polyester compound P1, the structural formula of which is shown below:

[0040] The characterization data are as follows: the above reaction obtained a white solid fluorine-containing polyester compound P1 in a yield of 89%, with a weight average molecular weight of 119 kDa and a molecular weight distribution of 2.08. 1 H NMR (DMSO- d 6, 400 MHz, ppm): 7.76 (d, J = 12.4 Hz, 2H), 5.62 (d, J = 12.4 Hz, 2H), 4.72 (t, J = 14.2 Hz, 8H). 13 C NMR (DMSO- d 6, 126 MHz, ppm): 165.11, 163.65, 115.23, 115.10, 97.34, 67.46, 58.53. 19 F NMR (DMSO- d 6, 376 MHz, ppm): -120.77, -121.53.

[0041] Figure 1 The nuclear magnetic resonance hydrogen spectra of the fluorine-containing polyester compound, its corresponding monomers, and the model small molecule ene ether are shown below (* indicates the solvent peak), in the hydrogen spectrum of monomer M1 (A in Figure 1 , the terminal alkyne proton resonance peak appears at delta = 4.83 ppm (peak 1), in the hydrogen spectrum of monomer M2 (B in Figure 1 , the proton peak of the hydroxyl group appears at delta = 5.73 ppm (peak 3), and in the spectrum of polymer P1 (D in Figure 1 , these two peaks almost completely disappear, indicating that the M1 and M2 monomers have been substantially completely reacted. In the hydrogen spectrum of the model small molecule ene ether (C in Figure 1 , the two proton signals of the vinyl group generated by the hydroxyl-alkyne click reaction appear at delta = 7.76 ppm (peak 6) and delta = 5.62 ppm (peak 7), which in the nuclear magnetic resonance hydrogen spectrum of polymer P1, at delta = 7.76 ppm (peak 9) and deltaBoth sets of peaks were also observed at 5.62 ppm (peak 10), which confirms the correctness of the polymer structure.

[0042] Carbon nuclear magnetic resonance spectroscopy further corroborated the structure of the polymer. For example... Figure 2 As shown in AD, in the carbon spectrum of M1, -C≡ C The resonance signal is located at delta = 73.40 ppm (peak a), and this signal disappeared in the spectra of both the model compound and polymer P1, indicating that M1 was successfully converted during polymerization. Furthermore, the resonance peaks of the two carbons on the vinyl group in the model compound are located at... delta = 163.25 ppm (peak j) and delta = 97.62 ppm (peak k), the corresponding signal in polymer P1 appears delta =163.65 ppm (peak o) and delta = 97.34 ppm (peak p), further verifying the polymer structure.

[0043] Nuclear magnetic resonance fluorine spectroscopy further confirmed the structure of the polymer. For example... Figure 3 As shown in AD, the chemical shift of the difluoromethylene group in monomer M1 is... delta = -120.59 ppm (peak 1), the chemical shift of the difluoromethylene group in M2 is delta = -123.26ppm (peak 2), the chemical shift of the difluoromethylene group in the model compound is delta = -120.74 ppm (peak 4). In polymer P1, the corresponding fluorine signals are located at... delta = -120.77 ppm (peak 5) and delta = -121.53 ppm (peak 6). It is noteworthy that the chemical shift of F1 did not change significantly before and after polymerization, while F2 shifted noticeably to a lower field after polymerization. delta = -121.53 ppm). This displacement can be attributed to the post-polymerization F2. β The hydroxyl group transforms into an ether structure with stronger electron-withdrawing properties, resulting in a decrease in the electron cloud density around it, which in turn causes a shift towards the lower field direction.

[0044] Figure 4 The figure shows the thermogravimetric analysis (TGA) curve of the fluorinated polyester compound P1. As can be seen from the figure, the decomposition temperature of P1 (measured by the temperature corresponding to a 5% weight loss) is 372 °C. This result indicates that the prepared fluorinated polyester compound P1 possesses excellent thermal stability, which provides an important foundation for its application in high-temperature environments.

[0045] Figure 5The refractive index curve of the fluorine-containing polyester compound P1 is shown in the figure. As can be seen from the figure, the refractive index of P1 reaches 1.4727 at a wavelength of 589.3 nm, indicating that the fluorine-containing polyester compound has excellent refractive performance. This low refractive index characteristic provides important potential for its application in the field of optical materials, such as low refractive index coating, optical devices, and display technology.

[0046] In addition, the fluorine-containing polyester compound P1 is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, and has excellent solubility.

[0047] Example 2 The monomer M1 (a binary fluorine-containing alkyne compound) is the same as in Example 1.

[0048] The monomer M3 (a binary fluorine-containing alcohol compound) is 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, which can be purchased on the market.

[0049] In this embodiment, the preparation method of the fluorine-containing polyester compound P2 is as follows: (1) Dissolve the monomer M1 (0.147 g, 0.400 mmol), the monomer M3 (0.105 g, 0.400 mmol) in 0.80 mL of tetrahydrofuran, and then add 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ); place the polymerization tube in an air atmosphere at room temperature and stir for 5 min; (2) Under stirring, add the polymer solution of step (1) dropwise to n-hexane, then filter and dry to constant weight under vacuum to obtain the fluorine-containing polyester compound P2, the structural formula of which is as follows:

[0050] The characterization data are as follows: the above reaction obtains the white solid fluorine-containing polyester compound P2 with a yield of 86%, the weight average molecular weight is 59.5 kDa, the molecular weight distribution is 1.71, the refractive index is 1.4522, and it is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, and has excellent solubility. 1 H NMR (DMSO- d 6, 500 MHz, ppm): 7.77 (d, J= 12.3 Hz, 2H), 5.63 (d, J = 12.3 Hz, 2H), 4.89 (t, J = 13.8 Hz, 4H), 4.73 (t, J = 14.8 Hz, 4H). 19 F NMR (DMSO- d 6, 376 MHz, ppm): -119.65, -120.77, -123.20.

[0051] Example 3 Monomer M1 (difluorine-containing acetylenic compound) is the same as Example 1.

[0052] Monomer M4 (difluorine-containing alcoholic compound) is 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol, which can be purchased on the market.

[0053] In this example, the preparation method of the difluorine-containing polyester compound P3 is as follows: (1) Dissolve monomer M1 (0.147 g, 0.400 mmol), monomer M4 (0.145 g, 0.400 mmol) in 0.80 mL of tetrahydrofuran, then add 0.20 mL of tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ); place the polymerization tube in a room temperature air atmosphere and stir for 5 min; (2) Under stirring, add the polymer solution of step (1) to n-hexane, then filter and dry to constant weight under vacuum to obtain the difluorine-containing polyester compound P3, whose structural formula is as follows:

[0054] The characterization data are as follows: the above reaction obtains the white solid difluorine-containing polyester compound P3 with a yield of 81%, a weight average molecular weight of 166 kDa, a molecular weight distribution of 2.03, and a refractive index of 1.4483. It is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide at room temperature, and has excellent solubility. 1 H NMR (THF- d 8, 400 MHz, ppm): 7.68 (d, J = 12.4 Hz, 2H), 5.56 (d, J = 12.4 Hz, 2H), 4.68 (m, 8H).19 F NMR (THF- d 8, 376 MHz, ppm): -120.73, -122.36, -122.72, -123.87.

[0055] Example 4 Monomer M1 (a binary fluorinated alkyne compound) is the same as in Example 1.

[0056] The monomer M5 (a difluorinated alcohol) is 1H,1H,10H,10H-perfluoro-1,10-decanediol, which is commercially available.

[0057] In this embodiment, the preparation method of the fluorinated polyester compound P4 includes the following steps: (1) In a 25 mL polymerization tube, monomer M1 (0.147 g, 0.400 mmol) and monomer M5 (0.185 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P4, whose structural formula is shown below:

[0058] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P4 in 88% yield, with a weight-average molecular weight of 45.4 kDa, a molecular weight distribution of 1.89, and a refractive index of 1.4464. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.57 (d, J = 12.4 Hz, 2H), 4.70 (m, 8H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.69, -122.36, -122.55, -123.78.

[0059] Example 5 The specific process of the synthesis method of monomer M6 (a binary fluorine-containing alkyne compound) in this embodiment is as follows: 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol (2.62 g, 10.0 mmol), N,N'-dicyclohexylcarbodiimide (6.19 g, 30.0 mmol), 4-dimethylaminopyridine (0.367 g, 3.00 mmol), p-toluenesulfonic acid (0.689 g, 4.00 mmol), and a stirring rod were added to a 100 mL round-bottom flask, followed by the addition of 30.0 mL of anhydrous dichloromethane. Propargyl acid (2.10 g, 1.85 mL, 30.0 mmol) was dissolved in 30.0 mL of anhydrous dichloromethane, and was slowly added dropwise under ice bath. After the dropwise addition was completed, stirring was performed at room temperature for 4 h. After the reaction was completed, filtration was performed, and column chromatography was performed using petroleum ether and dichloromethane as eluents to separate the product monomer M6, which was obtained in a yield of 79%, and the structure thereof is shown below:

[0060] Monomer M2 (a binary fluorine-containing alcohol compound) is the same as in Embodiment 1.

[0061] In this embodiment, the preparation method of the fluorine-containing polyester compound P5 is as follows: (1) In a 25 mL polymerization tube, monomer M6 (0.147 g, 0.400 mmol) and monomer M2 (0.0648 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration: 11.2 mg mL -1 ); the polymerization tube was placed in a room temperature air atmosphere and stirred for 5 min; (2) Under stirring, the polymer solution of step (1) was added dropwise to n-hexane, followed by filtration and vacuum drying to a constant weight to obtain the fluorine-containing polyester compound P5, and the structural formula thereof is shown below:

[0062] The characterization data are as follows: The above reaction obtained the white solid fluorine-containing polyester compound P5 in a yield of 89%, the weight average molecular weight was 101 kDa, the molecular weight distribution was 1.92, the refractive index was 1.4459, and the fluorine-containing polyester compound P5 was easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, and had excellent solubility. 1 H NMR (DMSO- d 6, 500 MHz, ppm): 7.77 (d, J= 12.4 Hz, 2H), 5.62 (d, J = 12.4 Hz, 2H), 4.83 (t, J = 14.4 Hz, 4H), 4.73 (t, J = 14.4 Hz, 4H). 19 F NMR (DMSO- d 6, 471 MHz, ppm): -118.94, -121.57, -123.37.

[0063] Example 6 Monomer M6 (difluorine-containing acetylenic compound) is the same as Example 5.

[0064] Monomer M3 (difluorine-containing alcoholic compound) is the same as Example 2.

[0065] In this embodiment, the preparation method of the difluorine-containing polyester compound P6 is as follows: (1) In a 25 mL polymerization tube, monomer M6 (0.147 g, 0.400 mmol), monomer M3 (0.105 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, and then 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ) was added; the polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min; (2) Under stirring, the polymer solution of step (1) was added dropwise to n-hexane, then filtered and vacuum dried to constant weight to obtain the difluorine-containing polyester compound P6, whose structural formula is as follows:

[0066] The characterization data are as follows: the above reaction obtained the white solid difluorine-containing polyester compound P6 with a yield of 90%, a weight average molecular weight of 65.0 kDa, a molecular weight distribution of 1.72, and a refractive index of 1.4429. It is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide at room temperature, and has excellent solubility. 1 F NMR (DMSO- d 6, 400 MHz, ppm): 7.78 (d, J = 12.4 Hz, 2H), 5.64 (d, J = 12.4 Hz, 2H), 4.86 (m, 8H). 19 F NMR (DMSO- d6,376 MHz, ppm): -118.92, -119.66, -123.23, -123.38.

[0067] Example 7 Monomer M6 (difluorine-containing alkyne compound) is the same as Example 5.

[0068] Monomer M4 (difluorine-containing alcohol compound) is the same as Example 3.

[0069] In this example, the preparation method of the difluorine-containing polyester compound P7 is as follows: (1) Dissolve monomer M6 (0.147 g, 0.400 mmol), monomer M4 (0.145 g, 0.400 mmol) in 0.80 mL of tetrahydrofuran, then add 0.20 mL of tetrahydrofuran solution containing 1,4-diazido bicyclo[2.2.2]octane (concentration is 11.2 mg mL -1 ); place the polymerization tube in a room temperature air atmosphere and stir for 5 min; (2) Under stirring, add the polymer solution of step (1) to n-hexane, then filter and vacuum dry to constant weight to obtain the difluorine-containing polyester compound P7, the structure of which is as follows:

[0070] The characterization data are as follows: the above reaction obtains the white solid difluorine-containing polyester compound P7 with a yield of 88%, the weight average molecular weight is 108 kDa, the molecular weight distribution is 1.85, the refractive index is 1.4240, and it is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide at room temperature, and has excellent solubility. 1 H NMR (THF- d 8, 500 MHz, ppm): 7.69 (d, J = 12.5 Hz, 2H), 5.56 (d, J = 12.5 Hz, 2H), 4.69 (m, 8H). 19 F NMR (THF- d 8, 471 MHz, ppm): -120.41, -120.70, -122.68, -123.86, -124.36.

[0071] Example 8 Monomer M6 (difluorine-containing alkyne compound) is the same as Example 5.

[0072] Monomer M5 (a binary fluorinated alcohol compound) is the same as in Example 4.

[0073] In this embodiment, the preparation method of the fluorinated polyester compound P8 includes the following steps: (1) In a 25 mL polymerization tube, monomer M6 (0.147 g, 0.400 mmol) and monomer M5 (0.185 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidadicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P8, whose structural formula is shown below:

[0074] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P8 in 90% yield, with a weight-average molecular weight of 54.4 kDa, a molecular weight distribution of 2.00, and a refractive index of 1.4176. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,500 MHz, ppm): 7.69 (d, J = 12.5 Hz, 2H), 5.57 (d, J = 12.5 Hz, 2H), 4.70 (m, 8H). 19 F NMR (THF- d 8, 471 MHz, ppm): -120.41, -120.66, -122.40, -122.55, -123.77, -124.37.

[0075] Example 9 The specific process of the synthesis method of monomer M7 (a binary fluorine-containing alkyne compound) in this embodiment is as follows: 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol (1.76 g, 5.00 mmol), N,N'-dicyclohexylcarbodiimide (3.09 g, 15.0 mmol), 4-dimethylaminopyridine (0.183 g, 1.50 mmol), p-toluenesulfonic acid (0.344 g, 2.00 mmol), and a stirring rod were added to a 100 mL round-bottom flask, followed by the addition of 20.0 mL of anhydrous dichloromethane. Propargyl acid (1.05 g, 0.923 mL, 15.0 mmol) was dissolved in 20.0 mL of anhydrous dichloromethane, and was slowly added dropwise under ice bath. After the addition was completed, the mixture was stirred at room temperature for 4 h. After the reaction was completed, the mixture was filtered, and the product monomer M7 was separated by column chromatography using petroleum ether and dichloromethane as eluents, with a yield of 72%. The structure is shown below:

[0076] Monomer M2 (a binary fluorine-containing alcohol compound) is the same as in Embodiment 1.

[0077] In this embodiment, the preparation method of the fluorine-containing polyester compound P9 is as follows: (1) In a 25 mL polymerization tube, monomer M7 (0.187 g, 0.400 mmol) and monomer M2 (0.0648 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ); the polymerization tube was placed in a room temperature air atmosphere and stirred for 5 min; (2) Under stirring, the polymer solution of step (1) was added dropwise to n-hexane, followed by filtration and vacuum drying to a constant weight to obtain the fluorine-containing polyester compound P9, the structure of which is shown below:

[0078] The characterization data are as follows: the above reaction obtained the white solid fluorine-containing polyester compound P9 with a yield of 80%, a weight average molecular weight of 46.8 kDa, a molecular weight distribution of 1.61, and a refractive index of 1.4386. The compound is easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, and has excellent solubility. 1 H NMR (THF- d 8, 400 MHz, ppm): 7.69 (d, J= 12.4 Hz, 2H), 5.54 (d, J = 12.4 Hz, 2H), 4.75 (t, J = 14.0 Hz, 4H), 4.56 (t, J = 13.6Hz, 4H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.20, -122.67, -122.81, -124.02.

[0079] Example 10 Monomer M7 (a binary fluorinated alkyne compound) is the same as in Example 9.

[0080] Monomer M3 (a binary fluorinated alcohol compound) is the same as in Example 2.

[0081] In this embodiment, the preparation method of the fluorinated polyester compound P10 includes the following steps: (1) In a 25 mL polymerization tube, monomer M7 (0.187 g, 0.400 mmol) and monomer M3 (0.105 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P10, whose structural formula is shown below:

[0082] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P10 in 87% yield, with a weight-average molecular weight of 284 kDa, a molecular weight distribution of 1.91, and a refractive index of 1.4287. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.56 (d, J = 12.4 Hz, 2H), 4.76 (m, 8H). 19 F NMR (THF-d 8,376 MHz, ppm): -120.19, -120.90, -122.67, -124.00, -124.23.

[0083] Example 11 Monomer M7 (difluorine-containing alkyne compound) is the same as Example 9.

[0084] Monomer M4 (difluorine-containing alcohol compound) is the same as Example 3.

[0085] In this example, the preparation method of the difluorine-containing polyester compound P11 is as follows: (1) In a 25 mL polymerization tube, monomer M7 (0.187 g, 0.400 mmol), monomer M4 (0.145 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, and then 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ) was added; the polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min; (2) Under stirring, the polymer solution of step (1) was added dropwise to n-hexane, then filtered and vacuum dried to constant weight to obtain the difluorine-containing polyester compound P11, the structural formula of which is as follows:

[0086] The characterization data are as follows: the above reaction obtained the white solid difluorine-containing polyester compound P11 with a yield of 86%, the weight average molecular weight was 180 kDa, the molecular weight distribution was 1.86, the refractive index was 1.4264, and it was easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide at room temperature, and had excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.57 (d, J = 12.4 Hz, 2H), 4.72 (m, 8H). 19 F NMR (THF- d 8,376 MHz, ppm): -120.19, -120.72, -122.68, -123.88, -124.02.

[0087] Example 12 Monomer M7 (difluorine-containing alkyne compound) is the same as Example 9.

[0088] Monomer M5 (a binary fluorinated alcohol compound) is the same as in Example 4.

[0089] In this embodiment, the preparation method of the fluorinated polyester compound P12 includes the following steps: (1) In a 25 mL polymerization tube, monomers M7 (0.187 g, 0.400 mmol) and M5 (0.185 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P12, whose structural formula is shown below:

[0090] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P12 in 83% yield, with a weight-average molecular weight of 54.7 kDa, a molecular weight distribution of 1.99, and a refractive index of 1.4180. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.57 (d, J = 12.4 Hz, 2H), 4.72 (m, 8H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.19, -120.67, -122.68, -123.78, -124.03.

[0091] Example 13 The specific process of the synthesis method of monomer M8 (a binary fluorine-containing alkyne compound) in this embodiment is as follows: 1H, 1H, 10H, 10H-perfluoro-1, 10-decanediol (2.31 g, 5.00 mmol), N, N'-dicyclohexyl carbodiimide (3.09 g, 15.0 mmol), 4-dimethylaminopyridine (0.183 g, 1.50 mmol), p-toluenesulfonic acid (0.344 g, 2.00 mmol) and a stirring rod were added to a 100 mL round-bottom flask, and then 20.0 mL of anhydrous dichloromethane was added. Propargyl acid (1.05 g, 0.923 mL, 15.0 mmol) was dissolved in 20.0 mL of anhydrous dichloromethane, and was slowly added dropwise under ice bath. After the dropwise addition was completed, stirring was performed at room temperature for 4 h. After the reaction was completed, filtration was performed, and column chromatography was performed with petroleum ether and dichloromethane as eluents to separate the product monomer M8, and the yield was 65%. The structure is shown below:

[0092] Monomer M2 (a binary fluorine-containing alcohol compound) is the same as in Embodiment 1.

[0093] In this embodiment, the preparation method of the fluorine-containing polyester compound P13 is as follows: (1) In a 25 mL polymerization tube, monomer M8 (0.227 g, 0.400 mmol) and monomer M2 (0.0648 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, and then 0.20 mL of a tetrahydrofuran solution containing 1, 4-diazido-bicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ) was added. The polymerization tube was placed in a room temperature air atmosphere and stirred for 5 min; (2) Under stirring, the polymer solution of step (1) was added dropwise to n-hexane, and then filtration and vacuum drying to constant weight were performed to obtain the fluorine-containing polyester compound P13, and the structural formula is shown below:

[0094] The characterization data are as follows: The above reaction obtained the white solid fluorine-containing polyester compound P13 with a yield of 91%, the weight average molecular weight was 212 kDa, the molecular weight distribution was 1.91, the refractive index was 1.4324, and the fluorine-containing polyester compound P13 was easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1, 4-dioxane, dimethylacetamide, dimethyl sulfoxide and N, N'-dimethyl formamide at room temperature, and had excellent solubility. 1 H NMR (THF- d 8, 400 MHz, ppm): 7.69 (d, J= 12.4 Hz, 2H), 5.54 (d, J = 12.4 Hz, 2H), 4.77 (t, J = 14.0 Hz, 4H), 4.56 (t, J = 13.6Hz, 4H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.15, -122.49, -122.82, -123.92.

[0095] Example 14 Monomer M8 (a binary fluorinated acetylene compound) is the same as in Example 13.

[0096] Monomer M3 (a binary fluorinated alcohol compound) is the same as in Example 2.

[0097] In this embodiment, the preparation method of the fluorinated polyester compound P14 includes the following steps: (1) In a 25 mL polymerization tube, monomer M8 (0.227 g, 0.400 mmol) and monomer M3 (0.105 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P14, whose structural formula is shown below:

[0098] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P14 in 92% yield, with a weight-average molecular weight of 123 kDa, a molecular weight distribution of 1.81, and a refractive index of 1.4226. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.56 (d, J = 12.4 Hz, 2H), 4.77 (t, J= 14.0 Hz, 4H), 4.66 (t, J = 13.6Hz, 4H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.13, -120.90, -122.49, -123.91, -124.24.

[0099] Example 15 Monomer M8 (a binary fluorinated acetylene compound) is the same as in Example 13.

[0100] Monomer M4 (a binary fluorinated alcohol compound) is the same as in Example 3.

[0101] In this embodiment, the preparation method of the fluorinated polyester compound P15 includes the following steps: (1) In a 25 mL polymerization tube, monomer M8 (0.227 g, 0.400 mmol) and monomer M4 (0.145 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidadicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P15, whose structural formula is shown below:

[0102] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P15 in 89% yield, with a weight-average molecular weight of 134 kDa, a molecular weight distribution of 1.84, and a refractive index of 1.4186. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.57 (d, J = 12.4 Hz, 2H), 4.74 (m, 8H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.13, -120.72, -122.50, -122.71, -123.91.

[0103] Example 16 Monomer M8 (a binary fluorinated acetylene compound) is the same as in Example 13.

[0104] Monomer M5 (a binary fluorinated alcohol compound) is the same as in Example 4.

[0105] In this embodiment, the preparation method of the fluorinated polyester compound P16 includes the following steps: (1) In a 25 mL polymerization tube, monomers M8 (0.227 g, 0.400 mmol) and M5 (0.185 g, 0.400 mmol) were dissolved in 0.80 mL of tetrahydrofuran, followed by the addition of 0.20 mL of a tetrahydrofuran solution containing 1,4-diazidadicyclo[2.2.2]octane (concentration 11.2 mg / mL). -1 The polymerization tube was placed in an air atmosphere at room temperature and stirred for 5 min. (2) Under stirring, the polymer solution from step (1) was added dropwise to n-hexane, then filtered and dried under vacuum to constant weight to obtain the fluorinated polyester compound P16, whose structural formula is shown below:

[0106] The characterization data are as follows: The above reaction yielded a white solid fluorinated polyester compound P16 in 93% yield, with a weight-average molecular weight of 50.3 kDa, a molecular weight distribution of 1.86, and a refractive index of 1.4136. It is readily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide, and N,N'-dimethylformamide at room temperature, exhibiting excellent solubility. 1 H NMR (THF- d 8,400 MHz, ppm): 7.69 (d, J = 12.4 Hz, 2H), 5.57 (d, J = 12.4 Hz, 2H), 4.74 (m, 8H). 19 F NMR (THF- d 8, 376 MHz, ppm): -120.13, -120.69, -122.51, -122.80, -123.93.

[0107] Example 17 Monomer M8 (a binary fluorinated acetylene compound) is the same as in Example 13.

[0108] Monomer M5 (a binary fluorinated alcohol compound) is the same as in Example 4.

[0109] Monomer M9 is glycerol, which is commercially available.

[0110] In this example, the branched fluorine-containing polyester compound P17 was prepared by the following steps: (1) Monomer M8 (0.228 g, 0.403 mmol), monomer M5 (0.185 g, 0.400 mmol), monomer M9 (0.184 mg, 0.002 mmol) were dissolved in 0.80 mL of tetrahydrofuran in a 25 mL polymerization tube, followed by adding 0.20 mL of tetrahydrofuran solution containing 1,4-diazidobicyclo[2.2.2]octane (concentration of 11.2 mg mL -1 ); the polymerization tube was placed in a room temperature air atmosphere and stirred for 5 min; (2) The polymer solution of step (1) was added dropwise to n-hexane under stirring, followed by filtration and vacuum drying to constant weight to obtain the branched fluorine-containing polyester compound P17, the structure of which is shown below:

[0111] The characterization data are as follows: the above reaction obtained the white solid fluorine-containing polyester compound P17 with a yield of 90%, the weight average molecular weight was 43.4 kDa, the molecular weight distribution was 1.85, the refractive index was 1.4084, it was easily soluble in common organic solvents such as tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide at room temperature, and had excellent solubility. 1 H NMR (THF- d 8, 500 MHz, ppm): 7.69 (d, J = 12.5 Hz, 2H), 5.57 (d, J = 12.0 Hz, 2H), 4.74 (m, 8H). 19 F NMR (THF- d 8, 471 MHz, ppm): -120.11, -120.66, -122.42, -122.54, -123.78, -123.92.

[0112] In this example, the polymerization of monomer M8 and monomer M5 was selected, a small amount of glycerol was introduced to make the structure of the polymer branched, so as to increase the molar volume of the polymer. Figure 6The refractive index curves of the fluorine-containing polyester compound P16 and the branched fluorine-containing polyester compound P17 are shown, and it can be seen from the figure that by introducing glycerol, the polymer structure is successfully branched, and the refractive index of the material is reduced from the original 1.4136 to 1.4084. This is because the branched space structure can increase the molar volume of the polymer, thereby reducing the refractive index of the material. It can be seen that this space structure regulation strategy not only can reduce the refractive index of the material, but also provides a new way for the development of high-performance low-refractive-index optical materials.

[0113] The above embodiments have described the technical solutions of the present application in detail, and it should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, supplement or similar replacement within the principle range of the present application shall be included in the protection scope of the present application.

Claims

1. A fluorinated polyester compound, characterized in that, The structural formula is as follows: ； （Ⅰ）； In formula (I), R 1 and R 2 each independently is a fluorine-substituted alkylene group having a carbon number of C3-C22; the polymerization degree n is in the range of 10-500.

2. The fluorine-containing polyester-based compound according to claim 1, characterized by, In formula (I), R 1 and R 2 are structural general formulae of , * indicates a connection position, wherein m is an integer of 1-20.

3. A branched fluorinated polyester compound, characterized in that, The structural formula is as follows: ； （Ⅱ）； ； （Ⅲ）； In formula (II) and formula (III), R 1 and R 2 are the same as in formula (I), R 3 is a triol residue, and R 4 is a tetrol residue.

4. The method for producing a fluoro-polyester-based compound according to claim 1 or 2, characterized by, The method comprises the following steps: Under the action of the base catalyst, the binary fluorine-containing alkyne compound and the binary fluorine-containing alcohol compound are subjected to a polymerization reaction in an organic solvent under an air atmosphere, and after the reaction is completed, post-treatment is performed to obtain the fluorine-containing polyester compound; The structural formula of the binary fluorine-containing acetylenic compound is The structural formula of the binary fluorine-containing alcohol compound is The definitions of R 1 and R 2 are the same as those in formula (I).

5. The method for producing a branched fluorine-containing polyester-based compound according to claim 3, characterized by, The method comprises the following steps: Under the action of the base catalyst, the binary fluorine-containing alkyne compound, the binary fluorine-containing alcohol compound and the polyhydric alcohol are subjected to a polymerization reaction in an organic solvent under an air atmosphere, and after the reaction is completed, post-treatment is performed to obtain the branched fluorine-containing polyester compound; the polyhydric alcohol is a trihydric alcohol or a tetrahydric alcohol. The structural formula of the binary fluorine-containing acetylenic compound is The structural formula of the binary fluorine-containing alcohol compound is R 1 and R 2 are the same as those in formula (I).

6. The preparation method according to claim 4, characterized in that, The molar ratio of the binary fluorine-containing alkyne compound to the binary fluorine-containing alcohol compound is 1:0.6-1.

5.

7. The preparation method according to claim 5, characterized in that, The molar ratio of the binary fluorine-containing alkyne compound, the binary fluorine-containing alcohol compound and the polyhydric alcohol is 1:0.6-1.5:0.001-0.

1.

8. The production method according to claim 4 or 5, characterized by, The temperature of the polymerization reaction is 0-100 °C, and the time of the polymerization reaction is 1-120 min.

9. The preparation method according to claim 4 or 5, characterized in that, The base catalyst is at least one of 1,4-diazidobicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, triethylamine, diisopropylethylamine, pyridine, 4-dimethylaminopyridine, sodium methoxide, sodium ethoxide, potassium tert-butoxide, potassium carbonate and cesium carbonate; And / or, the organic solvent is at least one of tetrahydrofuran, acetonitrile, dichloromethane, chloroform, benzene, toluene, ethyl acetate, 1,4-dioxane, dimethylacetamide, dimethyl sulfoxide and N,N'-dimethylformamide.

10. Application of the fluorine-containing polyester compound according to claim 1 or the branched fluorine-containing polyester compound according to claim 3 in the field of optics.

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