PTAA copolymer with photo-thermal stability and preparation method thereof

Abstract

The invention discloses a photo-thermal stable PTAA copolymer and a preparation method thereof, the structural formula of the photo-thermal stable PTAA copolymer is shown in the specification, R is selected from or at least one of R and n is 0.03-0.26. The copolymer has a PTAA conjugated main chain and piperazine side groups, and can realize good processability and improved photo-thermal stability.

Description

Technical Field

[0001] This invention belongs to the field of organic polymers, and particularly relates to a photothermally stable PTAA 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, PTAA faces significant photothermal stability issues in practical applications. Under photothermal conditions, 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, resulting in unstable film morphology and consequently affecting the long-term reliability of the material.

[0004] To address the aforementioned stability issues, existing technologies primarily employ two modification strategies. The first is physical blending or doping, which involves adding small-molecule antioxidants, light stabilizers, or UV absorbers to the PTAA matrix to inhibit photo-oxidation or thermal degradation. However, physical additives have limited compatibility with the polymer matrix and are prone to migration and precipitation during long-term use or thermal aging, leading to a decrease in protective effect. Furthermore, the additives themselves may introduce impurities, affecting the overall material performance. The second approach is chemical structural modification, which involves introducing fluorinated, siloxane, or crosslinking groups through copolymerization or side-group modification to improve the material's thermal stability or hydrophobicity. However, such modifications often sacrifice some degree of polymer processability and intrinsic functional properties.

[0005] Therefore, how to develop a PTAA-modified polymer that combines good processing performance and photothermal stability is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention discloses a photothermally stable PTAA copolymer and its preparation method. The copolymer has a PTAA conjugated backbone and piperazine side groups. By controlling the relative amount of piperazine side groups, good processing properties, such as film-forming properties and improved photothermal stability, can be achieved. Specifically, the piperazine side groups of this copolymer do not disrupt the skeletal structure and stacking characteristics of the PTAA conjugated backbone, and are beneficial for forming a uniform and dense film. Furthermore, in light and heat environments, the more reactive piperazine side groups are preferentially oxidized, thus protecting the PTAA conjugated backbone, thereby improving the photothermal stability of the copolymer.

[0007] The first objective of this invention is to provide a photothermally stable PTAA copolymer, the structural formula of which is shown in formula (I):

[0008] Equation (Ⅰ);

[0009] R is selected from or At least one of the following, where n is 0.03 to 0.26. For example, n can be 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, or 0.25.

[0010] In some embodiments of the present invention, the photothermally stable PTAA copolymer has a number-average molecular weight of 10-40 kDa and a PDI of 1.2-3.0. For example, the number-average molecular weight may be 12 kDa, 14 kDa, 16 kDa, 18 kDa, 20 kDa, 22 kDa, 24 kDa, 26 kDa, 28 kDa, 30 kDa, 32 kDa, 34 kDa, 36 kDa, 38 kDa, 30 kDa, 32 kDa, 34 kDa, 36 kDa, or 38 kDa.

[0011] In some embodiments of the present invention, R is selected from... When R is selected from this structure, it is beneficial to obtain better processability and photothermal stability at the same time.

[0012] A second objective of this invention is to provide a method for preparing the above-mentioned photothermally stable PTAA copolymer, characterized by comprising the following steps:

[0013] Under the action of palladium catalyst and auxiliaries, piperazine aniline compound, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl undergo a polymerization reaction to obtain the photothermally stable PTAA copolymer;

[0014] The piperazinyl aniline compound is selected from at least one of 4-(4-methylpiperazin-1-yl)aniline or 3-(4-methylpiperazin-1-yl)aniline.

[0015] In some embodiments of the present invention, the sum of the amounts of the piperazinylaniline compound and the 2,4,6-trimethylaniline is n1, the amount of the 4,4'-dibromobiphenyl is n2, and the ratio of n1 to n2 is 1:1 to 1.1.

[0016] In some embodiments of the present invention, the molar ratio of the piperazinyl aniline compound to the 2,4,6-trimethylaniline is 0.05~0.25:0.75~0.95.

[0017] In some embodiments of the present invention, the molar ratio of the palladium catalyst to the 4,4'-dibromobiphenyl is 0.005 to 0.03:1.

[0018] In some embodiments of the present invention, the structure of the palladium catalyst is shown in formula (II):

[0019] Equation (II), where R 1 R 2 It can be hydrogen, methyl, ethyl, or isopropyl independently, and R 1 R 2 They are not both hydrogen.

[0020] In some embodiments of the present invention, the auxiliary agent includes an organic base and a solvent.

[0021] In some embodiments of the present invention, the organic base is selected from potassium tert-butoxide.

[0022] In some embodiments of the present invention, the molar ratio of the organic base to the 4,4'-dibromobiphenyl is 2 to 4:1.

[0023] In some embodiments of the present invention, the solvent is selected from toluene.

[0024] In some embodiments of the present invention, the ratio of the solvent to the 4,4'-dibromobiphenyl is 2L~4L:1mol.

[0025] In some embodiments of the present invention, the polymerization reaction is carried out at a temperature of 100-120°C for 12-36 hours.

[0026] In some embodiments of the present invention, the polymerization reaction is carried out in an inert gas atmosphere.

[0027] In some embodiments of the present invention, a post-processing step is further included after the polymerization reaction is completed.

[0028] In some embodiments of the present invention, the post-processing step includes a step of precipitation with methanol.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The photothermally stable PTAA copolymer of the present invention has good film-forming properties. When observed by optical microscope, the number of defects such as shrinkage cavities, pinholes, bubbles or cracks with a long side ≥10μm in the film is less than or equal to 5, or even less than or equal to 2. Furthermore, after one month of photothermal cycling aging, the film retains more than 70% or even more than 80% of the transmittance T at 400~800nm. Attached Figure Description

[0030] Figure 1 The photothermally stable PTAA copolymer prepared in Example 7 of this invention 1 H NMR spectrum;

[0031] Figure 2 The photothermally stable PTAA copolymer prepared in Example 10 of this invention 1 H NMR spectrum. Detailed Implementation

[0032] 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.

[0033] All raw materials used in this invention are commercially available.

[0034] The structure of imidazole salt ligand L1 is shown below:

[0035] ;

[0036] The structure of imidazole salt ligand L2 is shown below:

[0037] ;

[0038] The structure of imidazole salt ligand L3 is shown below:

[0039] .

[0040] Example 1

[0041] This embodiment provides a palladium catalyst C1, the preparation method of which includes the following steps:

[0042] 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:

[0043] 1H 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).

[0044] 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.

[0045] The structure of palladium catalyst C1 is shown below:

[0046] .

[0047] Example 2

[0048] This embodiment provides a palladium catalyst C2, the preparation method of which includes the following steps:

[0049] 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:

[0050] 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).

[0051] 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.

[0052] The structure of palladium catalyst C2 is shown below:

[0053] .

[0054] Example 3

[0055] This embodiment provides a palladium catalyst C3, the preparation method of which includes the following steps:

[0056] 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:

[0057] 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).

[0058] 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.

[0059] The structure of palladium catalyst C3 is shown below:

[0060] .

[0061] Example 4

[0062] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0063] 3-(4-methylpiperazin-1-yl)aniline (0.05 mmol), 2,4,6-trimethylaniline (0.95 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C1 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, the structure of which is shown below:

[0064] .

[0065] Example 5

[0066] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0067] 3-(4-methylpiperazin-1-yl)aniline (0.1 mmol), 2,4,6-trimethylaniline (0.9 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C2 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, with the same structure as in Example 4.

[0068] Example 6

[0069] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0070] 3-(4-methylpiperazin-1-yl)aniline (0.15 mmol), 2,4,6-trimethylaniline (0.85 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C3 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, with the same structure as in Example 4.

[0071] Example 7

[0072] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0073] 3-(4-methylpiperazin-1-yl)aniline (0.2 mmol), 2,4,6-trimethylaniline (0.8 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. tBu (3 mmol), catalyst C2 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, with the same structure as in Example 4.

[0074] Example 8

[0075] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0076] 3-(4-methylpiperazin-1-yl)aniline (0.25 mmol), 2,4,6-trimethylaniline (0.75 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C2 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, with the same structure as in Example 4.

[0077] Example 9

[0078] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0079] 4-(4-methylpiperazin-1-yl)aniline (0.1 mmol), 2,4,6-trimethylaniline (0.9 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C2 (0.02 mmol), and 3 mL of toluene solution were added, and nitrogen gas was introduced. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, the structure of which is shown below:

[0080] .

[0081] Example 10

[0082] This embodiment provides a photothermally stable PTAA copolymer, the preparation method of which includes the following steps:

[0083] 4-(4-methylpiperazin-1-yl)aniline (0.2 mmol), 2,4,6-trimethylaniline (0.8 mmol), 4,4'-dibromobiphenyl (1 mmol), and KO were added to the reactor. t Bu (3 mmol), catalyst C2 (0.02 mmol), and 3 mL of toluene solution were added and purged with nitrogen. The reaction was carried out 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, stirred at room temperature for 24 h, filtered, and the filtrate was added dropwise to methanol to precipitate. The filtrate was washed 2-3 times with methanol solution, filtered, and dried to obtain a yellowish-white polymer, namely the photothermally stable PTAA copolymer, with the same structure as in Example 9.

[0084] The following test will be conducted:

[0085] 1. Weigh the photothermally stable PTAA copolymers obtained in Examples 4-10 above, calculate their yield, and the results are shown in Table 1.

[0086] 2. The photothermally stable PTAA copolymers obtained in Examples 4 to 10 above were subjected to GPC analysis to obtain their number-average molecular weight Mn and molecular weight distribution index PDI. The results are shown in Table 1.

[0087] 3. The photothermally stable PTAA copolymers obtained in Examples 4-10 above were subjected to... 1 ¹H NMR analysis was performed, and the ratio of H on the piperazine ring (δ 2.6~3.0 and δ 3.2~3.5) to methyl H on trimethylbenzene (δ 1.9~2.4) was integrated to determine the proportion of piperazine structural units in the copolymer, i.e. the n value in the copolymer structure. The results are shown in Table 1.

[0088] 4. Using 1,2-dichlorobenzene as a solvent, prepare a 10 mg / mL solution of the photothermally stable PTAA copolymer obtained in Examples 4-10 above, and a sample of PTAA (Mn approximately 17.74 kDa, PDI 2.39) + 10 wt% piperazine (as a comparative example), and then dissolve the PTAA in 50 μL / cm³ solution. 2The amount of film formed on the glass substrate by spin coating was used to form a thin film. The number of defects such as shrinkage cavities, pinholes, bubbles or cracks with a long side ≥10μm in a 50cm×50cm area of ​​the film was observed by optical microscope to evaluate the film-forming properties of the above samples. The results are shown in Table 1, where ◎ indicates 0~2 defects; ○ indicates 3~5 defects; and ╳ indicates more than 5 defects.

[0089] 5. After testing the visible light (400~800nm) transmittance T of the thin film samples in the above film-forming property evaluation, place them in a light environment during the day and in a 60℃ oven at night for 30 days. Test the visible light (400~800nm) transmittance T again and calculate the retention rate of transmittance T. The results are shown in Table 1.

[0090] Table 1: Properties of photothermally stable PTAA copolymers obtained in Examples 4-10 and comparative sample

[0091]

[0092] As shown in Table 1, the present invention successfully synthesized photothermally stable PTAA copolymers in Examples 4-10. Furthermore, the obtained copolymers have good film-forming properties and can maintain high light transmittance after photothermal cycling aging for one month, which means they have good photothermal stability.

[0093] 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. A photothermally stable PTAA copolymer, characterized in that, The structural formula of the photothermally stable PTAA copolymer is shown in Formula (Ⅰ): Equation (Ⅰ); R is selected from or At least one of them, where n is 0.03 to 0.

26.

2. The photothermally stable PTAA copolymer according to claim 1, characterized in that, The photothermally stable PTAA copolymer has a number-average molecular weight of 10~40kDa and a PDI of 1.2~3.

0.

3. The photothermally stable PTAA copolymer according to claim 1, characterized in that, The R is selected from .

4. The method for preparing the photothermally stable PTAA copolymer according to any one of claims 1 to 3, characterized in that, Includes the following steps: Under the action of palladium catalyst and auxiliaries, piperazine aniline compound, 2,4,6-trimethylaniline and 4,4'-dibromobiphenyl undergo a polymerization reaction to obtain the photothermally stable PTAA copolymer; The piperazinyl aniline compound is selected from at least one of 4-(4-methylpiperazin-1-yl)aniline or 3-(4-methylpiperazin-1-yl)aniline.

5. The method for preparing the photothermally stable PTAA copolymer according to claim 4, characterized in that, The sum of the amounts of the piperazinylaniline compound and the 2,4,6-trimethylaniline is n1, and the amount of the 4,4'-dibromobiphenyl is n2, where n1:n2 is 1:1 to 1.

1.

6. The method for preparing the photothermally stable PTAA copolymer according to claim 4, characterized in that, The molar ratio of the piperazinyl aniline compound to the 2,4,6-trimethylaniline is 0.05~0.25:0.75~0.

95.

7. The method for preparing the photothermally stable PTAA copolymer according to claim 4, characterized in that, The molar ratio of the palladium catalyst to the 4,4'-dibromobiphenyl is 0.005 to 0.03:

1.

8. The method for preparing the photothermally stable PTAA copolymer according to claim 4, characterized in that, The additives include organic bases and solvents.

9. The method for preparing the photothermally stable PTAA copolymer according to claim 8, characterized in that, The organic base is selected from potassium tert-butoxide; and / or, the molar ratio of the organic base to the molar ratio of the 4,4'-dibromobiphenyl is 2 to 4:

1.

10. The method for preparing the photothermally stable PTAA copolymer according to claim 8, characterized in that, The solvent is selected from toluene; and / or the ratio of the solvent to the 4,4'-dibromobiphenyl is 2L~4L:1mol.

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