An aldehyde-substituted copolymer and its preparation method

Abstract

This invention discloses an aldehyde-substituted copolymer and its preparation method, belonging to the field of organic polymer copolymer technology. The structural formula of the copolymer is shown below. The copolymer has a PTAA conjugated backbone and an aldehyde structure, which gives the copolymer good solubility and thermal stability. The solubility of the copolymer can also be controlled by adjusting the relative amount of the aldehyde structure.

Description

Technical Field

[0001] This invention belongs to the field of organic polymer copolymers, and particularly relates to an aldehyde-substituted copolymer and its preparation method. Background Technology

[0002] Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is a class of conjugated polymers with triarylamine units as the main chain. Due to its good light transmittance and tunable energy levels, it has attracted widespread attention in the field of functional materials.

[0003] However, existing PTAA materials still have significant drawbacks in practical applications. First, PTAA is a highly hydrophobic polymer, exhibiting good solubility only in nonpolar or weakly polar organic solvents such as toluene, chlorobenzene, and o-dichlorobenzene, while being almost insoluble in green solvents such as alcohols (e.g., methanol, ethanol, isopropanol). This solubility characteristic severely limits the applicability of its solution processing methods. Second, PTAA faces poor thermal stability issues in practical applications. The triarylamine structural units in the PTAA molecular chain readily absorb photon energy, undergoing oxidation reactions and generating degradation products such as free radical cations or carbonyl groups. This leads to the destruction of the polymer's conjugated structure, thereby affecting the long-term reliability of PTAA.

[0004] Therefore, modifying PTAA to obtain a copolymer with both good solubility and thermal stability has certain market value. Summary of the Invention

[0005] This invention discloses an aldehyde-substituted copolymer and its preparation method. The copolymer has a PTAA conjugated backbone and an aldehyde structure, resulting in good solubility and thermal stability. The solubility of the copolymer can also be controlled by adjusting the relative amount of the aldehyde group.

[0006] The first objective of this invention is to provide an aldehyde-substituted copolymer, the structural formula of which is shown in formula (I):

[0007] Equation (Ⅰ);

[0008] Where n is 0.6 to 0.98.

[0009] In some embodiments of the present invention, the number average molecular weight of the aldehyde-substituted copolymer is 5-30 kDa and the PDI is 1.1-2.5.

[0010] In some embodiments of the present invention, the aldehyde-substituted copolymer has an n value of 0.915, a number-average molecular weight Mn of 11277 g / mol, and a PDI of 1.53.

[0011] In some embodiments of the present invention, the aldehyde-substituted copolymer has an n value of 0.606, a number-average molecular weight Mn of 15238 g / mol, and a PDI of 2.47.

[0012] In some embodiments of the present invention, the aldehyde-substituted copolymer has an n value of 0.98, a number-average molecular weight Mn of 5192 g / mol, and a PDI of 1.1.

[0013] In some embodiments of the present invention, the aldehyde-substituted copolymer has an n value of 0.844, a number-average molecular weight Mn of 29153 g / mol, and a PDI of 1.95.

[0014] In some embodiments of the present invention, the aldehyde-substituted copolymer has an n value of 0.709, a number-average molecular weight Mn of 21048 g / mol, and a PDI of 2.23.

[0015] In some embodiments of the present invention, the raw materials for preparing the aldehyde-substituted copolymer include 3,5-dibromoanisole compounds, the structural formula of which is shown in formula (II) or formula (III) below:

[0016] Equation (II);

[0017] Formula (Ⅲ).

[0018] In some embodiments of the present invention, the raw materials for preparing the aldehyde-substituted copolymer also include 2,4,6-trimethylaniline.

[0019] In some embodiments of the present invention, the raw materials for preparing the aldehyde-substituted copolymer also include 4,4'-dibromobiphenyl.

[0020] Another object of the present invention is a method for preparing the aldehyde-substituted copolymer, comprising the following steps:

[0021] S1. An alkyl diol is mixed with 3,5-dibromobenzaldehyde, an organic strong acid catalyst, and a first solvent, heated to react, and purified to obtain the 3,5-dibromobenzaldehyde compound, wherein the alkyl diol is selected from ethylene glycol or propylene glycol;

[0022] S2. Under the action of palladium catalyst and auxiliaries, 3,5-dibromoanisole compounds, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl undergo a polymerization reaction to obtain ether-substituted copolymers;

[0023] S3. Under the action of a strong acid and a second solvent, the ether-substituted copolymer reacts to obtain the ester-substituted copolymer.

[0024] In some embodiments of the present invention, in S1, the molar ratio of the alkyl diol to 3,5-dibromobenzaldehyde and the organic strong acid catalyst is 3~7:0.5~1.5:0.01~0.03.

[0025] In some embodiments of the present invention, in S1, the organic strong acid catalyst is selected from p-toluenesulfonic acid.

[0026] In some embodiments of the present invention, in S1, the temperature of the heating reaction is 25~120°C and the time is 10~30 hours.

[0027] In some embodiments of the present invention, in S1, the first solvent is selected from toluene.

[0028] In some embodiments of the present invention, in S2, the molar ratio of the palladium catalyst, 3,5-dibromoanisole, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl is 0.02~0.06:0.2~0.6:1:0.4~0.8.

[0029] In some embodiments of the present invention, in S2, the structure of the palladium catalyst is shown in formula (Ⅳ):

[0030] Equation (Ⅳ), where R 1 R 2 It can be hydrogen, methyl, ethyl, or isopropyl independently, and R 1 R 2 They are not both hydrogen.

[0031] In some embodiments of the present invention, in S2, the auxiliary agent includes an organic base and a third solvent.

[0032] In some embodiments of the present invention, in S2, the molar ratio of the organic base to 2,4,6-trimethylaniline is 2 to 4:1.

[0033] In some embodiments of the present invention, in S2, the organic base is selected from potassium tert-butoxide.

[0034] In some embodiments of the present invention, in S2, the polymerization reaction is carried out at a temperature of 100-120°C for 12-36 hours.

[0035] In some embodiments of the present invention, in S2, the polymerization reaction is carried out in an inert gas atmosphere.

[0036] In some embodiments of the present invention, in step S2, a post-processing step is further included after the polymerization reaction is completed.

[0037] In some embodiments of the present invention, the molar ratio of the third solvent to 2,4,6-trimethylaniline is 2 mL to 4 mL: 1 mmol.

[0038] In some embodiments of the present invention, the third solvent is selected from toluene.

[0039] In some embodiments of the present invention, in S3, the strong acid includes hydrochloric acid.

[0040] In some embodiments of the present invention, in S3, the second solvent is selected from tetrahydrofuran.

[0041] In some embodiments of the present invention, in S3, the ratio of the ether-substituted copolymer to the strong acid and the second solvent is 0.8~1.2 mmol: 1 ml: 5~15 mL.

[0042] In some embodiments of the present invention, in step S3, the reaction temperature is 60-80°C and the time is 1-3 hours.

[0043] Compared with the prior art, the present invention has the following beneficial effects: by introducing an appropriate amount of aldehyde structure with significant electron-withdrawing inductive effect and conjugation effect into the PTAA backbone structure, the solubility and thermal stability of the copolymer are effectively improved. Attached Figure Description

[0044] Figure 1 The ether-substituted copolymer prepared in Example 4 of this invention 1 H NMR spectrum.

[0045] Figure 2 The aldehyde-substituted copolymer prepared in Example 4 of this invention 1 H NMR spectrum. Detailed Implementation

[0046] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0047] All raw materials used in this invention are commercially available.

[0048] The structure of imidazole salt ligand L1 is shown below:

[0049] ;

[0050] The structure of imidazole salt ligand L2 is shown below:

[0051] ;

[0052] The structure of imidazole salt ligand L3 is shown below:

[0053] .

[0054] Copolymerization percentage calculation: The copolymer consists of trimethylaniline units (T), biphenyl units (A), and benzaldehyde units (B). In the ¹H NMR spectrum:

[0055] 1. A trimethylaniline unit contains 9 methyl hydrogen atoms, and its integral area is denoted as I. CH3 ;

[0056] 2. The benzaldehyde unit contains one aldehyde hydrogen atom, and the integral area is denoted as I. CHO .

[0057] Based on the relationship between the integral ratio and the number of hydrogen atoms:

[0058] ;

[0059] Based on the stoichiometric relationship of CN coupling polymerization, [T] = [A] + [B], the total number of repeating units in the polymer is [T] + [A] + [B] = 2[T]. Therefore, the mole fraction F of benzaldehyde units in the total repeating units of the polymer is... B for:

[0060] ;

[0061] When the methyl hydrogen integral is normalized to 9 (i.e., I...) CH3 When =9), it simplifies to:

[0062] .

[0063] Example 1

[0064] This embodiment provides a palladium catalyst C1, the preparation method of which includes the following steps:

[0065] Imidazole salt ligand L1 (1.0 mmol), potassium carbonate (10 mmol), and palladium dichloride (1.0 mmol) were added to 10 mL of N-methylimidazole and mixed at room temperature. The mixture was then heated to 80°C and stirred for 12 hours. After the reaction was completed, the liquid was removed under reduced pressure, and the crude product was dissolved in 5 mL of dichloromethane. Subsequently, 20 mL of n-hexane was added, and the resulting palladium complex precipitate was collected by filtration, washed with n-hexane (2 × 20 mL), and dried to obtain a grayish-white palladium catalyst powder C1 with a yield of 81%. The NMR C-H spectrum of palladium catalyst C1 is as follows:

[0066] 1 H NMR (400 MHz, CDCl3) δ 7.50 (td, J = 1.6, 0.8 Hz, 1H), 7.12-7.07(m, 5H), 7.00 (dd, J = 5.6, 1.7 Hz, 1H), 6.85-6.81 (m, 4H), 6.60 (s, 4H), 3.82 (s, 6H), 3.72 (d, J = 0.6 Hz, 3H), 2.31 (s, 12H), 2.26 (d, J = 0.7 Hz, 6H).

[0067] 13 C NMR (101 MHz, CDCl3) δ 162.02, 156.48, 133.58, 133.45, 133.24,130.79, 130.15, 129.44, 127.53, 122.13, 116.03, 103.07, 62.77, 55.35, 35.03,21.03, 18.14.

[0068] The structure of palladium catalyst C1 is shown below:

[0069] .

[0070] Example 2

[0071] This embodiment provides a palladium catalyst C2, the preparation method of which includes the following steps:

[0072] Imidazole salt ligand L2 (1.0 mmol), potassium carbonate (8 mmol), and palladium dichloride (1.0 mmol) were added to 8 mL of N-methylimidazole and mixed at room temperature. The mixture was then heated to 70°C and stirred for 16 hours. After the reaction was completed, the liquid was removed under reduced pressure, and the crude product was dissolved in 5 mL of dichloromethane. Subsequently, 20 mL of n-hexane was added, and the resulting palladium complex precipitate was collected by filtration, washed with n-hexane (2 × 20 mL), and dried to obtain a grayish-white palladium catalyst powder C2 with a yield of 76%. The NMR C-H spectrum of palladium catalyst C2 is as follows:

[0073] 1H NMR (400 MHz, CDCl3) δ 7.50 (tt, J = 1.4, 0.7 Hz, 1H), 7.13-7.08(m, 5H), 7.00 (dd, J = 5.6, 1.7 Hz, 1H), 6.87-6.80 (m, 8H), 6.79-6.73 (m,2H), 3.82 (s, 6H), 3.72 (t, J = 0.7 Hz, 3H), 2.50 (qd, J = 7.5, 0.9 Hz, 8H), 1.26 (t, J = 7.5 Hz, 12H).

[0074] 13 C NMR (101 MHz, CDCl3) δ 162.02, 156.48, 141.57, 136.09, 130.79,129.44, 128.76, 127.53, 127.01, 122.13, 116.03, 103.07, 62.77, 55.35, 35.03,24.15, 14.23.

[0075] The structure of palladium catalyst C2 is shown below:

[0076] .

[0077] Example 3

[0078] This embodiment provides a palladium catalyst C3, the preparation method of which includes the following steps:

[0079] Imidazole salt ligand L3 (1.0 mmol), potassium carbonate (12 mmol), and palladium dichloride (1.0 mmol) were added to 12 mL of N-methylimidazole and mixed at room temperature. The mixture was then heated to 90°C and stirred for 10 hours. After the reaction was completed, the liquid was removed under reduced pressure, and the crude product was dissolved in 5 mL of dichloromethane. Subsequently, 20 mL of n-hexane was added, and the resulting palladium complex precipitate was collected by filtration, washed with n-hexane (2 × 20 mL), and dried to obtain a grayish-white palladium catalyst powder C3 with a yield of 74%. The NMR C-H spectrum of palladium catalyst C3 is as follows:

[0080] 1H NMR (400 MHz, CDCl3) δ 7.50 (tt, J = 1.5, 0.7 Hz, 1H), 7.12-7.08(m, 5H), 7.00 (dd, J = 5.6, 1.7 Hz, 1H), 6.94-6.90 (m, 4H), 6.85-6.81 (m,4H), 6.76 (dd, J = 8.8, 7.7 Hz, 2H), 3.82 (s, 6H), 3.72 (t, J = 0.7 Hz, 3H), 2.89 (hd, J = 6.8, 0.7 Hz, 4H), 1.28 (d, J = 6.9 Hz, 24H).

[0081] 13 C NMR (101 MHz, CDCl3) δ 162.02, 156.48, 144.25, 141.09, 130.79,129.44, 127.53, 127.24, 126.60, 122.13, 116.03, 103.07, 62.77, 55.35, 35.03,28.88, 24.04.

[0082] The structure of palladium catalyst C3 is shown below:

[0083] .

[0084] Example 4

[0085] This embodiment provides an aldehyde-substituted copolymer, the preparation method of which includes the following steps:

[0086] S1. 3,5-Dibromobenzaldehyde (10 mmol), ethylene glycol (50 mmol), p-toluenesulfonic acid (0.2 mmol), and 50 mL of toluene solution were added to the reactor. A water separator and condenser were connected, and the reaction was carried out at 130 °C for 20 h. After the reaction, the mixture was extracted with ethyl acetate-water and washed 3–5 times with sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain 3,5-dibromobenzyl ether compounds in 97.95% yield.

[0087] S2. 3,5-Dibromoanisole compound (0.4 mmol), 2,4,6-trimethylaniline (1 mmol), 4,4'-dibromobiphenyl (0.6 mmol), and KO were added to the reactor. tBu (3 mmol), palladium catalyst C1 (0.04 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The mixture was reacted at 110 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to a methanol solution to precipitate. The precipitate was washed 2-3 times with methanol solution, filtered, and dried to obtain a crude polymer. The crude polymer was dissolved in THF, and the resulting filtrate was added dropwise to a methanol solution to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a light yellow polymer, i.e., an ether-substituted copolymer, with a yield of 53%.

[0088] S3. Dissolve the above ether-substituted copolymer (0.25 mmol) in 10 mL THF, add 0.25 mL HCl, raise the temperature to 70 °C, react for 2 h, cool to room temperature, adjust the pH to 7 with 1 M NaOH, stir for 1 h, precipitate in methanol, dry, and obtain a yellow solid, i.e., the ester-substituted copolymer, with a yield of 82%, a copolymerization rate of 8.5% (i.e., n value of 0.915), a number-average molecular weight Mn of 11277 g / mol, and a PDI of 1.53.

[0089] The structural formulas of the 3,5-dibromoanisole compounds are shown below:

[0090] ;

[0091] The structural formula of the ether-substituted copolymer is shown below:

[0092] ;

[0093] The structure of the aldehyde-substituted copolymer is shown below:

[0094] .

[0095] Example 5

[0096] This embodiment provides an aldehyde-substituted copolymer, which differs from Example 4 only in step S2. Its preparation method includes the following steps:

[0097] S1. 3,5-Dibromobenzaldehyde (10 mmol), ethylene glycol (50 mmol), p-toluenesulfonic acid (0.2 mmol), and 50 mL of toluene solution were added to the reactor. A water separator and condenser were connected, and the reaction was carried out at 130 °C for 20 h. After the reaction, the mixture was extracted with ethyl acetate-water and washed 3–5 times with sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain 3,5-dibromobenzyl ether compounds in 97.95% yield.

[0098] S2. 3,5-Dibromoanisole (0.6 mmol), 2,4,6-trimethylaniline (1 mmol), 4,4'-dibromobiphenyl (0.4 mmol), and KO were added to the reactor. t Bu (4 mmol), palladium catalyst C2 (0.06 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The mixture was reacted at 110 °C for 36 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to a methanol solution to precipitate. The precipitate was washed 2-3 times with methanol solution, filtered, and dried to obtain a crude polymer. The crude polymer was dissolved in THF, and the resulting filtrate was added dropwise to a methanol solution to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a light yellow polymer, i.e., an ether-substituted copolymer, with a yield of 65%.

[0099] S3. Dissolve the above ether-substituted copolymer (0.25 mmol) in 10 mL THF, add 0.25 mL HCl, raise the temperature to 70 °C, react for 2 h, cool to room temperature, adjust the pH to 7 with 1 M NaOH, stir for 1 h, precipitate in methanol, dry, and obtain a yellow solid, i.e., the ester-substituted copolymer, with a yield of 85%, a copolymerization rate of 39.4% (i.e., n value of 0.606), a number-average molecular weight Mn of 15238 g / mol, and a PDI of 2.47.

[0100] The structural formulas of the 3,5-dibromoanisole compounds are shown below:

[0101] ;

[0102] The structural formula of the ether-substituted copolymer is shown below:

[0103] ;

[0104] The structure of the aldehyde-substituted copolymer is shown below:

[0105] .

[0106] Example 6

[0107] This embodiment provides an aldehyde-substituted copolymer, which differs from Example 4 only in step S2. Its preparation method includes the following steps:

[0108] S1. 3,5-Dibromobenzaldehyde (10 mmol), ethylene glycol (50 mmol), p-toluenesulfonic acid (0.2 mmol), and 50 mL of toluene solution were added to the reactor. A water separator and condenser were connected, and the reaction was carried out at 130 °C for 20 h. After the reaction, the mixture was extracted with ethyl acetate-water and washed 3–5 times with sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain 3,5-dibromobenzyl ether compounds in 97.95% yield.

[0109] S2. 3,5-Dibromoanisole compound (0.2 mmol), 2,4,6-trimethylaniline (1 mmol), 4,4'-dibromobiphenyl (0.8 mmol), and KO were added to the reactor. t Bu (2 mmol), palladium catalyst C3 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The mixture was reacted at 110 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature and added dropwise to a methanol solution to precipitate. The precipitate was washed 2-3 times with methanol solution, filtered, and dried to obtain a crude polymer. The crude polymer was dissolved in THF, and the resulting filtrate was added dropwise to a methanol solution to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a light yellow polymer, i.e., an ether-substituted copolymer, with a yield of 42%.

[0110] S3. Dissolve the above ether-substituted copolymer (0.25 mmol) in 10 mL THF, add 0.25 mL HCl, raise the temperature to 70 °C, react for 2 h, cool to room temperature, adjust the pH to 7 with 1 M NaOH, stir for 1 h, precipitate in methanol, dry, and obtain a yellow solid, i.e., the ester-substituted copolymer, with a yield of 74%, a copolymerization rate of 2% (i.e., n value of 0.98), a number-average molecular weight Mn of 5192 g / mol, and a PDI of 1.1.

[0111] The structural formulas of the 3,5-dibromoanisole compounds are shown below:

[0112] ;

[0113] The structural formula of the ether-substituted copolymer is shown below:

[0114] ;

[0115] The structure of the aldehyde-substituted copolymer is shown below:

[0116] .

[0117] Example 7

[0118] This embodiment provides an aldehyde-substituted copolymer, which differs from Example 4 only in step S2. Its preparation method includes the following steps:

[0119] S1. 3,5-Dibromobenzaldehyde (10 mmol), ethylene glycol (50 mmol), p-toluenesulfonic acid (0.2 mmol), and 50 mL of toluene solution were added to the reactor. A water separator and condenser were connected, and the reaction was carried out at 130 °C for 20 h. After the reaction, the mixture was extracted with ethyl acetate-water and washed 3–5 times with sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain 3,5-dibromobenzyl ether compounds in 97.95% yield.

[0120] S2. Add 0.45 mmol of 3,5-dibromoanisole, 1 mmol of 2,4,6-trimethylaniline, 0.65 mmol of 4,4'-dibromobiphenyl, and KO to the reactor. t Bu (3.5 mmol), palladium catalyst C1 (0.06 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out at 110 °C for 36 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to methanol solution to precipitate. The precipitate was washed 2-3 times with methanol solution, filtered, and dried to obtain crude polymer. The crude polymer was dissolved in THF, and the resulting filtrate was added dropwise to methanol solution to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a light yellow polymer, i.e., an ether-substituted copolymer, with a yield of 70%.

[0121] S3. Dissolve the above ether-substituted copolymer (0.25 mmol) in 10 mL THF, add 0.25 mL HCl, raise the temperature to 70 °C, react for 2 h, cool to room temperature, adjust the pH to 7 with 1 M NaOH, stir for 1 h, precipitate in methanol, dry, and obtain a yellow solid, i.e., the ester-substituted copolymer, with a yield of 88%, a copolymerization rate of 15.6% (i.e., n value of 0.844), a number-average molecular weight Mn of 29153 g / mol, and a PDI of 1.95.

[0122] The structural formulas of the 3,5-dibromoanisole compounds are shown below:

[0123] ;

[0124] The structural formula of the ether-substituted copolymer is shown below:

[0125] ;

[0126] The structure of the aldehyde-substituted copolymer is shown below:

[0127] .

[0128] Example 8

[0129] This embodiment provides an aldehyde-substituted copolymer, which differs from Example 4 only in step S2. Its preparation method includes the following steps:

[0130] S1. 3,5-Dibromobenzaldehyde (10 mmol), ethylene glycol (50 mmol), p-toluenesulfonic acid (0.2 mmol), and 50 mL of toluene solution were added to the reactor. A water separator and condenser were connected, and the reaction was carried out at 130 °C for 20 h. After the reaction, the mixture was extracted with ethyl acetate-water and washed 3–5 times with sodium bicarbonate aqueous solution. The organic phase was dried over anhydrous sodium sulfate, filtered, and rotary evaporated to obtain 3,5-dibromobenzyl ether compounds in 97.95% yield.

[0131] S2. 3,5-Dibromoanisole compound (0.5 mmol), 2,4,6-trimethylaniline (1 mmol), 4,4'-dibromobiphenyl (0.7 mmol), and KO were added to the reactor. t Bu (3 mmol), palladium catalyst C1 (0.05 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The mixture was reacted at 110 °C for 30 h. After the reaction was completed, the mixture was cooled to room temperature and added dropwise to a methanol solution to precipitate. The precipitate was washed 2-3 times with methanol solution, filtered, and dried to obtain a crude polymer. The crude polymer was dissolved in THF, and the resulting filtrate was added dropwise to a methanol solution to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a light yellow polymer, i.e., an ether-substituted copolymer, with a yield of 68%.

[0132] S3. Dissolve the above ether-substituted copolymer (0.25 mmol) in 10 mL THF, add 0.25 mL HCl, raise the temperature to 70 °C, react for 2 h, cool to room temperature, adjust the pH to 7 with 1 M NaOH, stir for 1 h, precipitate in methanol, dry, and obtain a yellow solid, i.e., the ester-substituted copolymer, with a yield of 86%, a copolymerization rate of 29.1% (i.e., n value of 0.709), a number-average molecular weight Mn of 21048 g / mol, and a PDI of 2.23.

[0133] The structural formulas of the 3,5-dibromoanisole compounds are shown below:

[0134] ;

[0135] The structural formula of the ether-substituted copolymer is shown below:

[0136] ;

[0137] The structure of the aldehyde-substituted copolymer is shown below:

[0138] .

[0139] Comparative Example 1

[0140] This comparative example provides a PTAA polymer, the preparation method of which includes the following steps:

[0141] 2,4,6-trimethylaniline (1 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), palladium catalyst C1 (0.02 mmol), and 3 mL of toluene were added, and the mixture was purged with nitrogen and reacted at 110 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, added dropwise to methanol to precipitate, washed 2-3 times with methanol, filtered, and dried to obtain the crude polymer. The crude polymer was dissolved in THF, stirred at room temperature for 24 h, filtered, and the resulting filtrate was added dropwise to methanol to precipitate, washed 2-3 times with methanol, filtered, and dried to obtain the PTAA polymer, the structure of which is shown below:

[0142] .

[0143] The following tests were performed on the copolymer / polymer obtained above:

[0144] 1. The aldehyde-substituted copolymers obtained in Examples 4-8 and the PTAA polymer obtained in Comparative Example 1 were subjected to alcohol solubility tests. The specific test method was as follows: In 1 mL of methanol, copolymers / polymers with different mass concentrations relative to methanol were added, shaken, and the time it took for them to completely dissolve into a transparent solution at room temperature or under heating conditions was recorded. The results are shown in Table 1 ("insoluble" means that no transparent solution was formed after shaking at 40°C for 10 min).

[0145] 2. Thermal stability was tested using TGA (Thermogravimetric Analysis): Thermogravimetric analysis-differential scanning calorimetry was performed at a heating rate of 10 °C / min under constant air flow of 100 mL / min. The results are shown in Table 1.

[0146] Table 1:

[0147]

[0148] As shown in the accompanying drawings, the present invention successfully synthesized aldehyde-substituted copolymers. As shown in Table 1, compared to the PTAA polymer, the aldehyde-substituted copolymers obtained in Examples 4-8 of the present invention exhibit good alcohol solubility and thermal stability.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading this application specification, they can still modify or make equivalent substitutions to the specific implementation of the present invention, but these modifications or changes do not depart from the protection scope of the pending claims of the present invention.

Claims

1. An aldehyde-substituted copolymer, characterized in that, The structural formula of the aldehyde-substituted copolymer is shown in Formula (I): Equation (Ⅰ); Where n is 0.6 to 0.98; The number-average molecular weight of the aldehyde-substituted copolymer is 5-30 kDa, and the PDI is 1.1-2.

5.

2. The aldehyde-substituted copolymer according to claim 1, characterized in that, The aldehyde-substituted copolymer has an n value of 0.915, a number-average molecular weight Mn of 11277 g / mol, and a PDI of 1.

53. Alternatively, the aldehyde-substituted copolymer has an n value of 0.606, a number-average molecular weight Mn of 15238 g / mol, and a PDI of 2.

47. Alternatively, the aldehyde-substituted copolymer has an n value of 0.98, a number-average molecular weight Mn of 5192 g / mol, and a PDI of 1.1; Alternatively, the aldehyde-substituted copolymer has an n value of 0.844, a number-average molecular weight Mn of 29153 g / mol, and a PDI of 1.95; Alternatively, the aldehyde-substituted copolymer has an n value of 0.709, a number-average molecular weight Mn of 21048 g / mol, and a PDI of 2.

23.

3. The aldehyde-substituted copolymer according to claim 1, characterized in that, The raw materials for preparing the aldehyde-substituted copolymer include 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl.

4. The aldehyde-substituted copolymer according to claim 3, characterized in that, The raw materials for preparing the aldehyde-substituted copolymer also include 3,5-dibromoanisole compounds, the structural formula of which is shown in formula (II) or formula (III) below: Equation (II); Formula (Ⅲ).

5. A method for preparing the aldehyde-substituted copolymer according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. An alkyl diol is mixed with 3,5-dibromobenzaldehyde, an organic strong acid catalyst, and a first solvent, heated to react, and purified to obtain 3,5-dibromobenzaldehyde compounds, wherein the alkyl diol is selected from ethylene glycol or propylene glycol; S2. Under the action of palladium catalyst and auxiliaries, 3,5-dibromoanisole compounds, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl undergo a polymerization reaction to obtain ether-substituted copolymers; S3. Under the action of a strong acid and a second solvent, the ether-substituted copolymer reacts to obtain the aldehyde-substituted copolymer.

6. The method for preparing the aldehyde-substituted copolymer according to claim 5, characterized in that, In S1, the molar ratio of the alkyl diol to 3,5-dibromobenzaldehyde and the organic strong acid catalyst is 3~7:0.5~1.5:0.01~0.03; And / or, the heating reaction is carried out at a temperature of 25~120°C for a time of 10~30 hours; And / or, the organic strong acid catalyst is selected from p-toluenesulfonic acid.

7. The method for preparing the aldehyde-substituted copolymer according to claim 5, characterized in that, In S2, the molar ratio of the palladium catalyst, 3,5-dibromoanisole, 2,4,6-trimethylaniline, and 4,4'-dibromobiphenyl is 0.02~0.06:0.2~0.6:1:0.4~0.

8. And / or, the structure of the palladium catalyst is shown in formula (Ⅳ): Equation (Ⅳ), where R 1 R 2 It can be hydrogen, methyl, ethyl, or isopropyl independently, and R 1 R 2 They are not both hydrogen.

8. The method for preparing the aldehyde-substituted copolymer according to claim 5, characterized in that, In S2, the auxiliary agent includes an organic base and a third solvent; And / or, the molar ratio of the organic base to 2,4,6-trimethylaniline is 2 to 4:1; And / or, the organic base is selected from potassium tert-butoxide; And / or, the polymerization reaction is carried out at a temperature of 100~120°C for a time of 12~36 hours; And / or, the polymerization reaction is carried out in an inert gas atmosphere; And / or, the polymerization reaction may include a post-processing step after completion.

9. The method for preparing the aldehyde-substituted copolymer according to claim 5, characterized in that, In S3, the strong acid includes hydrochloric acid; And / or, the second solvent is selected from tetrahydrofuran.

10. The method for preparing the aldehyde-substituted copolymer according to claim 5, characterized in that, In S3, the ratio of the ether-substituted copolymer to the strong acid and the second solvent is 0.8~1.2 mmol: 1 ml: 5~15 mL.

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