Polyarylamide with triphenylamine structure modified by trifluoromethyl and carbazole and preparation method of polyarylamide

Abstract

The invention discloses polyarylamide with a triphenylamine structure modified by trifluoromethyl and carbazole and a preparation method of the polyarylamide, and belongs to the technical field of modified polyamide materials. The structural formula of the polyarylamide with the trifluoromethyl and carbazole modified triphenylamine structure is as follows: the trifluoromethyl and carbazole modified triphenylamine structure is introduced into a main chain of a polyarylamide molecule, so that the polyarylamide is endowed with good solubility, thermal properties, optical transparency, lower dielectric constant and the like, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to a polyamide, in particular to a polyarylamide with a trifluoromethyl and carbazole modified triphenylamine structure, and also to a preparation method thereof, belonging to the technical field of modified polyamide materials. Background Art

[0002] Polyamide (PA), commonly known as nylon, is an engineering thermoplastic. Due to its heat resistance, chemical resistance and excellent mechanical properties, it has been widely used in many fields, such as the automotive industry, electronics and electrical appliances, textile industry, machinery industry or other fields.

[0003] Traditional aromatic PA is widely used in many fields due to its excellent comprehensive performance. However, due to the crystallization properties of its aggregated structure and the rigidity of its molecular structure, the polymer has poor solubility and a high glass transition temperature, which makes it difficult to process and shape the polymer material, severely limiting the application of polyamide. At present, there are two main types of modification methods for aromatic polyamide, namely physical modification (such as physical and chemical blending, doping with inorganic nanoparticles or carbon fiber, glass fiber, etc.) and chemical modification (structural modification). Many studies have shown that by designing and modifying the molecular structure, the shortcomings of aromatic polyamide, such as poor solubility, high glass transition temperature, and difficult processing and shaping, can be effectively improved. At present, the modification research on polyamide mainly focuses on the following directions:

[0004] (1) Introducing flexible structural units: Introducing flexible structures such as ether bonds, sulfide bonds, and sulfone groups into the polymer backbone can effectively enhance the flexibility of the macromolecular chain, thereby reducing the rigid structural characteristics of the aromatic polymer. This not only significantly improves the solubility of the polymer in the solvent, but also helps to improve the processability of the polyamide material. For example, the literature (“Synthesis and characterization of soluble aromatic polyamides containing double sulfide bond and thiazole ring”, Rezania J, et al. Polymer Bulletin, 2019, 76: 1547–1556) reported that the disulfide bond (-SS-) and thiazole ring were introduced into the PA skeleton. The prepared polyamide varieties showed good solubility and were amorphous materials.

[0005]

[0006] (2) Introducing twisted non-coplanar structures: Introducing structural units with non-planar twisted configurations such as triphenylamine can not only effectively inhibit the close packing of the polymer main chain, but also significantly weaken the symmetry of the material system, resulting in a decrease in the melting temperature of PA while improving its solubility. In addition, the introduction of twisted non-coplanar structures can also effectively lighten the color of the polymer, thereby improving its optical properties. For example, the literature (“Optically transparent polyamides bearing phenoxyl, diphenylamine and fluorene units with high-contrast of electrochromic and electrofluorescent behaviors”, Meng SY, et al. Polymer, 2017, 116: 89-98) prepared a series of flexible and highly transparent polyamide films containing phenoxyl, diphenylamine and fluorene groups, which have excellent solubility and thermal stability. Their color and fluorescence can be reversibly adjusted by electrochemical redox, and can be used as smart materials in electrochromic and electrofluorescent applications.

[0007]

[0008] (3) Introducing bulky side groups: By introducing bulky side groups (such as tert-butyl, phenyl, biphenyl, and heterocyclic side groups) into the molecular chain, the tight packing of the molecular chains can be disrupted, the intermolecular interactions can be weakened, and the intermolecular gaps can be increased, facilitating solvent penetration and diffusion. At the same time, bulky side groups have a certain degree of rigidity, which can improve solubility while minimizing their impact on thermal properties. For example, the document (“Synthesis and characterization of soluble and heat-resistant aromatic polyamides derived from diamine;N-(3,5-diaminophenyl)-4-(naphthalen-7-yloxy)benzamide and various aromatic diacids”, Espeso JF, et al. J. Macromol. Sci. A 2021, 58(10):677–685) discloses a novel aromatic polyamide prepared by the reaction and condensation of a diamine monomer containing naphthoxybenzamide side groups with various aromatic dicarboxylic acids. Due to the presence of bulky naphthoxybenzamide side groups, the prepared polymer has good heat resistance (its glass transition temperature is between 224-262°C, and its 10% thermal weight loss temperature is greater than 550°C) and solubility, and exhibits excellent film-forming ability.

[0009]

[0010] (4) Introduction of fluorinated groups: Fluorinated polyaromatic amides have excellent comprehensive properties (including high thermal stability, good chemical resistance, low dielectric constant, low refractive index, low surface tension, and low water absorption), which makes them show great potential in multiple application fields. The literature (“High optical transparency, low dielectric constant and light color of novel organosoluble polyamides with bulkyalicyclic pendent group”. Liaw DJ, et al. Polymer, 2007, 48: 6571-6580) discloses a series of fluorinated cardo-type aromatic polyamides. The results show that the introduction of trifluoromethyl side groups can effectively improve the solubility of the polymer, reduce its dielectric constant, and increase its light transmittance.

[0011]

[0012] (5) Introduction of heterocyclic structures: By introducing heterocyclic structures (such as carbazole, furan and pyridine), the thermal stability, antioxidant and chemical stability of polymers can be effectively improved. For example, the literature (“Novel triphenylaminepolyamides bearing carbazole and aniline substituents for multi-colored electrochromic applications”, Liu Y, et al. Dyes and Pigments, 2020, 173 (1): 107955) discloses the synthesis and properties of a fully aromatic polyamide with a triphenylamine structure substituted by carbazole and aniline. The polyamide has good solubility, good redox reversibility, long-term cycle stability, high color contrast and fast switching speed. In addition, it exhibits electrochromic behavior in both organic electrolyte solvents and hydrochloric acid, showing a wide range of application potential in electrochromic materials.

[0013]

[0014] In summary, the polyamide modification methods disclosed in the prior art are all single and limited, and the comprehensive properties of the modified polyamide are difficult to be effectively improved. Summary of the Invention

[0015] In response to the technical defects of polyaromatic amides in the prior art, the first object of the present invention is to provide a polyaromatic amide with a trifluoromethyl and carbazole-modified triphenylamine structure. By introducing twisted, non-coplanar triphenylamine structural units substituted with trifluoromethyl and bulky carbazole side groups into the polyaromatic amide main chain, the polyaromatic amide can be endowed with excellent solubility, thermal stability, optical transparency, and a low dielectric constant, thereby achieving excellent comprehensive physical properties.

[0016] In order to achieve the above technical objectives, the present invention provides a trifluoromethyl and carbazole modified triphenylamine polyarylamide having the following molecular structure:

[0017]

[0018] Wherein, Ar is the following aromatic group:

[0019] n is the degree of polymerization.

[0020] The invention designs and synthesizes trifluoromethyl and carbazole-modified triphenylamine units with special structures and introduces them into the main chain of polyaromatic amide, thereby giving the polyaromatic amide excellent comprehensive properties. The designed trifluoromethyl and carbazole-modified triphenylamine structural units have the following characteristics: 1) The introduction of bulky carbazole side groups can effectively reduce intermolecular interactions, increase intermolecular free volume, and prevent close packing of polymer molecular chains, thereby weakening its crystallization ability, lowering its melting temperature, increasing its solubility, and improving its photoelectric properties. 2) The introduced trifluoromethyl side groups, based on the trifluoromethyl group's strong electron-withdrawing effect, can effectively inhibit the formation of charge transfer complexes (CTCs), thereby significantly improving the optical transparency of polyamides. At the same time, their unique steric hindrance effect increases the distance between molecular chains, preventing close arrangement of molecular chains, further improving its solubility and lowering the dielectric constant. 3) The substituted triphenylamine has a bulky structure, which can reduce the regularity of the main chain and increase the spacing between polymer chains, thereby effectively reducing the degree of main chain stacking, weakening the interactions between and within the molecular chains, and reducing the probability of CTC formation, thereby improving the solubility and transmittance of polyamides. In summary, the introduction of trifluoromethyl and carbazole-modified triphenylamine structural units can impart good comprehensive properties to polyamides.

[0021] As a preferred solution, the number average molecular weight of the polyaromatic amide with triphenylamine structure modified by trifluoromethyl and carbazole is 42250-54560 g / mol, which has a relatively large molecular weight and good processing and film-forming properties.

[0022] The present invention also provides a method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure, wherein the method comprises subjecting a diamine monomer and a diacyl chloride monomer to a condensation polymerization reaction under the promotion of pyridine to obtain the polyaromatic amide.

[0023] The diamine monomer has the following molecular structure:

[0024]

[0025] The diacyl chloride monomer has the following molecular structure:

[0026]

[0027] in,

[0028] Ar is the following aromatic group:

[0029]

[0030] As a preferred solution, the diamine monomer and the diacyl chloride monomer are measured in an equimolar ratio. A high or low ratio of the diamine monomer to the diacyl chloride monomer will result in a low molecular weight of the polyaramid.

[0031] As a preferred solution, the polycondensation reaction conditions are: first react at -5 to 5°C for 1 to 2 hours, then react at room temperature for 10 to 12 hours. Because the condensation reaction between the acyl chloride group and the amino group is relatively violent, to prevent violent polymerization, it is necessary to prepolymerize at a low temperature of around 0°C, and then react at room temperature to increase the molecular weight.

[0032] As a preferred solution, the polycondensation reaction is carried out in anhydrous N,N-dimethylacetamide (DMAc).

[0033] As a preferred solution, the amount of N,N-dimethylacetamide used is to maintain the solid content of the polymerization system at 20-25%.

[0034] Compared with the existing technology, the technical solution of the present invention brings the following beneficial technical effects:

[0035] The present invention designs and synthesizes N,N-bis(4-amino-2-trifluoromethylphenyl)-3-trifluoromethyl-4-(carbazole-9-yl)aniline monomers, which contain asymmetric, bulky carbazole and trifluoromethyl-substituted non-coplanar triphenylamine structural units. The monomers are introduced into the main chain of polyaromatic amide, which can significantly improve the solubility, optical properties, heat resistance, mechanical properties, dielectric properties and hydrophobic properties of the polyaromatic amide.

[0036] The trifluoromethyl and carbazole modified triphenylamine structure polyaromatic amide has a transmittance of 80.3-83.8% at 500nm and a cutoff wavelength range of 373-392nm. It has high optical transparency and a light color, which is almost colorless.

[0037] The trifluoromethyl and carbazole-modified triphenylamine polyarylamide of the present invention has low water absorption and dielectric constant while maintaining good mechanical and thermal properties. For example, the dielectric constant of this series of polyarylamide at a frequency of 1 kHz is 1.00 to 2.13, the water absorption range is between 0.42% and 0.95%, and the water contact angle is as high as 90.5° to 96.9°. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 PA3 with triphenylamine structure modified by trifluoromethyl and carbazole 1 HNMR spectrum.

[0039] Figure 2 The infrared spectra of PA1-PA5 with trifluoromethyl and carbazole modified triphenylamine structures.

[0040] Figure 3 UV-vis curves of PA1-PA5 with trifluoromethyl and carbazole modified triphenylamine structures.

[0041] Figure 4 TGA (a) and DMA curves (b) of PA1-PA5 with trifluoromethyl and carbazole modified triphenylamine structures.

[0042] Figure 5 These are the stress-strain curves of PA1-PA5 with trifluoromethyl and carbazole modified triphenylamine structures. DETAILED DESCRIPTION

[0043] The following specific examples are intended to further illustrate the present invention in detail, rather than to limit the scope of protection of the claims.

[0044] The raw materials and reagents involved in the following examples are all conventional commercially available products.

[0045] Test and characterization methods:

[0046] (1) Fourier transform infrared spectroscopy (FT-IR): The sample was prepared with KBr as the background and tested using a Spectrum Two model FT-IR. The wave number was set to 4000 to 400 cm -1 .

[0047] (2) Nuclear magnetic resonance spectroscopy (NMR): Weigh 5-20 mg and dissolve in CDCl3 or DMSO-d6. Use Avance 400 MHz NMR spectrometer to measure the 1 H NMR and 13 C NMR test.

[0048] (3) Melting point test: The melting point was determined using a micro melting point apparatus (FCE-3000).

[0049] (4) Solubility test: Dissolve 10 mg of polymer in 1 mL of solvent (common solvents such as NMP, DMAc, and Py) at room temperature and observe the dissolution of the sample. If the sample is not completely dissolved, heat it to 60°C and continue observing and recording its dissolution.

[0050] (5) Molecular weight test: The sample was prepared into a 3-5 mg / mL solution and measured using a DAWN HELEOS II multi-angle laser light scattering instrument with THF as the mobile phase at a flow rate of 0.5 mL / min to obtain the weight-average molecular weight of the polymer. w , number average M n and dispersion index PDI.

[0051] (6) Thermogravimetric test: In a N2 atmosphere, TG-DTA was used to perform a thermogravimetric test, with the temperature increased at 10°C / min, and the thermogravimetric loss of the sample was tested in the range of 20 to 800°C.

[0052] (7) Dynamic mechanical analysis (DMA) test: DMA was used to characterize the heat resistance of the polymer. The film was cut into 5 cm × 5 mm fiber strips, fixed on a fixture, and the heating rate was set to 10 °C / min from room temperature to 420 °C at a parameter of 1 Hz.

[0053] (8) Optical performance test: The polymer film was cut into a size of 20 mm × 45 mm and tested using a U-3310 ultraviolet-visible spectrometer (UV-vis) with the wavelength set to 200 to 800 nm.

[0054] (9) Mechanical property test: The polymer film was cut into 2 mm × 50 mm size and subjected to tensile test using a CMT8012 universal electronic testing machine. The tensile speed was set to 5 mm / min, and the test was repeated three times to obtain the average value.

[0055] (10) Water absorption test: First, dry the polymer film in an oven at 100°C, cut the dried PA film into 10 mm × 10 mm pieces, and weigh M dry , soak in deionized water for 24 hours, wipe the surface moisture of the film, weigh M wet , calculate the water absorption (W U ).

[0056] W U Calculation formula: W U =[(M wet –M dry ) / M dry ]×100%; where M dry : Dry mass / g, M wet : Mass after water absorption / g.

[0057] (11) Water contact angle test: The hydrophobicity of the polymer was tested using a contact angle meter (OCA15EC). The test liquid was distilled water. The film was cut into 8 mm × 8 mm pieces and attached to the double-sided tape on a glass slide. The test was performed at room temperature.

[0058] (12) Dielectric property test: The E4980A precision impedance analyzer was used for testing. The polymer film was cut into 15 mm × 15 mm size, and the conductive adhesive was cut into 8 mm length. The conductive adhesive was pasted to both sides of the film and placed on the test fixture for testing at room temperature. The test frequency was 0.1 kHz to 100 kHz.

[0059] Example 1

[0060] The synthetic route of N,N-bis(4-amino-2-trifluoromethylphenyl)-3-trifluoromethyl-4-(carbazol-9-yl)aniline (V) is as follows:

[0061]

[0062] (1) Synthesis of 2-chloro-5-nitrotrifluorotoluene (I):

[0063] In an ice bath, 45.25 g (0.25 mol) of o-chlorobenzotrifluoride and 42 mL of concentrated sulfuric acid were added to a three-necked flask and stirred uniformly. 84 mL of a mixed solution of concentrated sulfuric acid and concentrated nitric acid (V:V = 1:1) was then added dropwise. The mixture was stirred at room temperature for 8 h. Upon completion of the reaction, the product was washed sequentially with water and saturated sodium chloride solution. The mixture was allowed to stand for separation. The lower layer of oil was separated by flash column chromatography using PE as the eluent to obtain 52.55 g of a light yellow oily liquid I (93% yield).

[0064] 1 H NMR (400MHz, CDCl3, δ, ppm): 8.58 (s, 1H), 8.36 (d, J = 10.1 Hz, 1H), 7.73 (d, J = 8.8 Hz, 1H).

[0065] (2) Synthesis of N-(4-nitro-2-trifluoromethylphenyl)carbazole (II):

[0066] To a three-necked flask, 30.06 g (0.18 mol) of carbazole, 24.84 g (0.18 mol) of anhydrous potassium carbonate, and 220 mL of DMF were added. Under nitrogen protection, the temperature was raised to 80°C, and 40.68 g (0.18 mol) of compound I was added. The mixture was reacted at 150°C for 8 h. Water was added and stirred to precipitate a solid, which was filtered, dried, and recrystallized from ethanol to obtain 55.62 g of yellow needle-like crystals II (86.8% yield).

[0067] 1 H NMR (400MHz, CDCl3, δ, ppm): 8.87 (s, 1H), 8.61 (d, 1H), 8.15 (d, J = 8.4Hz, 2H), 7.61 (d, J=8.5Hz, 1H), 7.40 (t, J=8.3Hz, 2H), 7.36-7.30 (m, 2H), 6.93 (d, J=8.0Hz, 2H).

[0068] (3) Synthesis of N-(4-amino-2-trifluoromethylphenyl)carbazole (III):

[0069] To a three-necked flask, 3.56 g (0.01 mol) of compound II, 0.20 g of 5% Pd / C, and 40 mL of anhydrous ethanol were added. Under nitrogen protection, the temperature was raised to 60°C, and 20 mL of hydrazine hydrate was slowly added dropwise. The reaction was stirred at 80°C for 12 h. The reaction solution was filtered while hot to remove palladium on carbon, which was then precipitated with ice water. After filtration, it was dried in vacuo at 80°C to obtain 2.74 g of a light yellow powder of solid III with a yield of 84.2%.

[0070] 1 H NMR (400MHz, DMSO-d6, δ, ppm): 8.18 (d, J = 7.7 Hz, 2H), 7.36 (t, J = 7.6 Hz, 2H), 7. 23(t,J=7.4Hz,2H),7.16(s,1H),7.10(s,1H),7.00-6.91(m,3H),6.02(s,2H).

[0071] (4) Synthesis of N,N-bis(4-nitro-2-trifluoromethylphenyl)-3-trifluoromethyl-4-(carbazol-9-yl)aniline (IV):

[0072] To a three-necked flask, 3.26 g (0.05 mol) of Intermediate III, 13.80 g (0.1 mol) of anhydrous potassium carbonate, and DMF (100 mL) were added. Under N₂ protection, the temperature was raised to 80°C, 27.12 g (0.12 mol) of 2-chloro-5-nitro-trifluorotoluene was added, and the temperature was raised to 150°C. The reaction was stirred for 10 hours. Ice water precipitated the product, which was filtered and washed with copious amounts of water. The product was recrystallized from dichloromethane, filtered, and dried to yield 28.90 g of light yellow powder IV. The yield was 82.1%, and the melting point was 125-126°C.

[0073] 1H NMR (400MHz, CDCl3, δ, ppm): 8.70 (s, 2H), 8.47 (dd, J = 8.9Hz, 2H), 8.13 (d, J = 7.6Hz, 2H ),7.44-7.39(m,4H),7.38(d,J=1.2Hz,1H),7.34-7.27(m,4H),6.93(d,J=8.1Hz,2H).

[0074] 13 C NMR (150MHz, CDCl3, δ, ppm): 149.70, 147.96, 145.18, 143.16, 134.19, 133.38, 131.29, 129.36, 128.58, 126.31, 125.46, 123.69, 120.47, 109.40.

[0075] (5) Synthesis of N,N-bis(4-amino-2-trifluoromethylphenyl)-3-trifluoromethyl-4-(carbazol-9-yl)aniline (V)

[0076] To a three-necked flask, 7.04 g (0.01 mol) of compound IV, 0.20 g of 5% Pd / C, and 40 mL of anhydrous ethanol were added. Under N2 protection, the temperature was raised to 60°C, and 20 mL of hydrazine hydrate was slowly added dropwise. The reaction was incubated at 80°C for 12 h. The reaction solution was filtered while hot to remove palladium on carbon, precipitated with ice water, and the solid was dried under vacuum at 80°C to obtain a crude product. Purification by column chromatography (PE / DCM (V:V = 3:1) as eluent) yielded 5.67 g of V, a light pink powder; the yield was 82.1%, and the melting point was 84-85°C.

[0077] 1 H NMR (400MHz, DMSO-d6, δ, ppm): 8.19 (d, J = 7.7Hz, 2H), 7.39 (d, J = 8.2Hz, 2H), 7.25 (t, J = 7.6Hz ,3H),7.09(d,J=8.7Hz,2H),6.96(t,J=2.7Hz,3H),6.87(dd,J=8.7,2.7Hz,5H),5.72(s,4H).

[0078] 13 C NMR(150MHz,DMSO-d6,δ,ppm):147.08,142.31,132.58,129.17,128.27,126.17,1 24.64,123.90,122.83,122.49,122.09,120.36,119.78,117.99,113.20,109.59.

[0079] Example 2

[0080] Preparation of trifluoromethyl and carbazole modified triphenylamine structure polyarylamide (PA1 ~ PA5):

[0081]

[0082] Taking the synthesis of polymer PA3 as an example, in a 50mL three-necked flask under N2 protection, 0.6445g (1mmol) of diamine monomer V and 0.2792g (1mmol) of 4,4'-biphenyldicarboxylic acid chloride were dissolved in DMAc (3.7mL). Py (0.1mL) was added and stirred in an ice bath for 1 hour. The mixture was then allowed to react at room temperature for 10 hours. After the reaction, an appropriate amount of methanol was added to precipitate the solid, which was then filtered, thoroughly extracted with methanol, filtered, and dried to obtain polymer PA3.

[0083] PA1 1 H NMR (600MHz, DMSO-d6, δ, ppm): 10.83 (s, 2H), 8.51-7.90 (m, 11H), 7.29 (t, J = 110.7Hz, 9H), 6.99 (s, 2H).

[0084] PA2 1 H NMR (600MHz, DMSO-d6, δ, ppm): 11.14 (s, 2H), 8.50 (s, 2H), 8.23 ​​(t, J = 40.2Hz, 6H), 7.94 (s, 2H), 7.57 (d, J = 16.6Hz, 11H), 6.99 (s, 2H).

[0085] PA3 1 H NMR (400MHz, DMSO-d6, δ, ppm): 10.80 (s, 2H), 8.50 (s, 2H), 8.31 (d, J = 50.2Hz, 8H), 7.98 (d, J = 8.3Hz, 4H), 7.41 (s, 5H), 7.24 (d, J = 28.7Hz, 4H), 6.86 (s, 2H).

[0086] PA4 1 H NMR (400MHz, DMSO-d6, δ, ppm): 10.67 (s, 2H), 8.38 (s, 2H), 8.18 (t, J = 10.5Hz, 4H), 8.03 (d, J=8.0Hz, 4H), 7.44 (m, J=36.5Hz, 6H), 7.19 (t, J=9.4Hz, 8H), 6.90 (d, J=22.5Hz, 5H).

[0087] PA5 1H NMR (400MHz, DMSO-d6, δ, ppm): 10.65 (s, 2H), 8.41 (s, 2H), 8.21 (t, J = 8.6Hz, 4H), 8.09 (d, J = 8.1Hz, 4H), 8.00 (d, J = 8.4Hz, 1H), 7.45 (m, 5H), 7.26 (d, J = 8.4Hz, 5H), 7.17 (d, J = 8.0Hz, 2H), 6.94 (s, 2H).

[0088] Example 3

[0089] Preparation of polyaromatic amide films with trifluoromethyl and carbazole modified triphenylamine structures:

[0090] Taking PA3 as an example, 0.10-0.12g of PA3 was dissolved in 3mL of DMAc, mixed evenly by ultrasonication, and filtered with an organic nanofiltration membrane. Then, the PA mucus was evenly dropped onto a preheated glass plate using the extension method. The plate was dried at 80°C for 2h until most of the DMAc was removed, and then dried at 100°C for another 2h. After cooling, the plate was peeled off to obtain a dry, transparent polyaramid film PA3.

[0091] Performance testing and characterization

[0092] (1) Molecular weight of polyaromatic amide with trifluoromethyl and carbazole modified triphenylamine structure:

[0093] The specific data of the trifluoromethyl and carbazole modified triphenylamine polyamides are shown in Table 1. As can be seen from Table 1, the M w (5.11~6.68)×10 4 g / mol,M n (4.22~5.45)×10 4 g / mol, and the distribution index is 1.15-1.28, indicating that this series of polymers has a high molecular weight, indicating that it has good film-forming properties.

[0094] Table 1. Molecular weight of polyaramid PA1-PA5

[0095]

[0096] a M w : weight average molecular weight; b M n : number average molecular weight; c PDI: Polydispersity Index (M w / M n ).

[0097] (2) Solubility properties of trifluoromethyl and carbazole modified triphenylamine polyamide:

[0098] As shown in Table 2, this series of polymers exhibits good solubility in both polar solvents (DMF, DMAc, DMSO, and NMP) and low-boiling-point solvents (THF). This is due to the presence of twisted, non-coplanar triphenylamine structures, bulky carbazole, and trifluoromethyl groups in the polymer molecular chains, which increase the interchain spacing and reduce tight packing between the molecular chains, allowing for easy solvent penetration and thus exhibiting good solubility.

[0099] Table 2. Solubility of polyaromatic amides PA1-PA5 in different solvents

[0100]

[0101] ---: does not dissolve upon heating; +--: partially dissolves upon heating; +++: dissolves at room temperature

[0102] (3) Light transmittance of trifluoromethyl and carbazole modified triphenylamine polyamide:

[0103] The UV-vis curve of this series of polyarylamide is as follows Figure 3 As shown in Table 3, the specific data can be seen from the table. It can be seen that the transmittance of this series of polymers at 500nm reaches 80%, which has good light transmittance. This is because the main chain of this series of polyarylamide macromolecules contains non-coplanar triphenylamine, bulky carbazole and trifluoromethyl side groups, which increases the steric hindrance, increases the distance between chains, reduces the packing density of molecular chains, inhibits the formation of CTC, and improves the optical transparency of the polymer film. Among them, PA5 has the best light transmittance, T 500nm 83.8%, T 800nm The content of free volume in the polyols was 87.7%, which was due to the large number of ether bonds, which could weaken the close packing of macromolecular chains, increase the free volume fraction, and thus reduce the formation of CTC.

[0104] Table 3. Optical properties of polyaramid PA1-PA5

[0105]

[0106] a Transmittance at 500nm, 600nm, 700nm, and 800nm; b Cut-off wavelength.

[0107] (4) Thermal properties of trifluoromethyl and carbazole modified polyaromatic amide with triphenylamine structure:

[0108] The thermal performance data of this series of polyaromatic amide PA1-PA5 are shown in Table 4. As can be seen from the table, this series of polymers has good heat resistance, T g 255.0~325.7℃, T d5 430.7~453.0℃, T d10The maximum thermal weight loss temperature is 523.4-547.8℃, and the residual carbon rate at 800℃ is above 60%. Among them, PA3 has the best thermal stability due to the high rigidity of the biphenyl structure in the molecular chain, stable molecular structure, and is not easy to decompose. PA4 has a low glass transition temperature (255.0℃) and T d5 is 449.6℃, T d10 The temperature is 487.8℃, and the thermal stability is good.

[0109] Table 4 Thermal properties of polyaramid PA1-PA5

[0110]

[0111]

[0112] aGlass transition temperature; b 5% thermal weight loss temperature; c 10% thermal weight loss temperature;

[0113] d Maximum thermal weight loss temperature; e Carbon residue rate at 800℃.

[0114] (5) Mechanical properties of trifluoromethyl and carbazole modified triphenylamine polyamides

[0115] Table 5 shows the mechanical properties of polyaramids PA1-PA5. As can be seen from Table 5, the tensile strength of PA1-PA5 ranges from 87.87 to 169.84 MPa, the elastic modulus from 2.15 to 3.74 MPa, and the elongation at break from 2.89 to 10.19%. PA2 has the lowest tensile strength and elongation at break, likely due to the presence of naphthalene in its molecular chain, which results in a rigid molecular structure and, consequently, lower tensile strength and elongation. PA5, on the other hand, has the highest tensile strength and elongation at break, at 169.84 MPa and 10.19%, respectively. This is due to the presence of ether bonds, which likely form hydrogen bonds with surrounding hydrogen atoms, increasing intermolecular forces and, consequently, increasing its tensile strength and elongation.

[0116] Table 5 Mechanical properties of polyaramid PA1-PA5

[0117]

[0118] a T s : tensile strength; T m : elastic modulus; E b : Elongation at break.

[0119] (6) Water absorption and water contact angle of trifluoromethyl and carbazole modified triphenylamine polyamide:

[0120] The contact angles and water absorption rates of polyaramids PA1-PA5 are shown in Table 6. As can be seen from Table 6, this series of polymer films all exhibit low water absorption (0.48-0.95%) and high water contact angles (90.5-96.9°), demonstrating excellent hydrophobicity. PA2 and PA3 exhibit low water absorption rates due to the presence of rigid structures such as naphthalene or biphenyl, which increase the degree of conjugation and enhance hydrophobicity, resulting in lower water absorption rates. PA4, with its more ether bonds in the main chain, exhibits the highest water absorption rate. This is due to the heteroatomic oxygen atoms in its structure forming hydrogen bonds with H2O molecules, thereby increasing its water absorption rate.

[0121] Table 6 Contact angle and water absorption of polyaromatic amide PA1-PA5

[0122]

[0123] (7) Dielectric properties of trifluoromethyl and carbazole modified triphenylamine polyamides:

[0124] The dielectric properties of polyaromatic amides PA1-PA5 (Table 7) show that this series of polymers all have low dielectric constants, ranging from 0.92 to 1.99 at 10 kHz. This is due to the combined effects of non-coplanar triphenylamine, bulky carbazole, and trifluoromethyl side groups in their main chains, which increase the distance between molecular chains and the free volume fraction, effectively reducing the dielectric constant of the polymer. PA3 has the lowest dielectric constant due to the presence of a rigid biphenyl structure in its molecular structure, which results in dense molecular chain packing and low water absorption, resulting in a low dielectric constant. PA4, on the other hand, contains a large number of hydrophilic ether groups, which easily absorb water. Its high water absorption rate leads to a relatively high dielectric constant.

[0125] Table 7 Dielectric properties of polyaramid PA1-PA5

[0126]

[0127] aDielectric constant measured at room temperature.

Claims

1. A polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure, characterized in that: It has the following molecular structure: Wherein, Ar is the following aromatic group: n is the degree of polymerization.

2. The polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 1, characterized in that: The number average molecular weight is 42250~54560g / mol.

3. The method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 1 or 2, characterized in that: The diamine monomer and the diacyl chloride monomer are subjected to condensation polymerization under the promotion of pyridine to obtain a polyarylamide with a trifluoromethyl and carbazole modified triphenylamine structure. The diamine monomer has the following molecular structure: The diacyl chloride monomer has the following molecular structure: in, Ar is the following aromatic group:

4. The method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 3, characterized in that: The diamine monomer and the diacyl chloride monomer are measured in an equimolar ratio.

5. The method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 3 or 4, characterized in that: The conditions of the polycondensation reaction are: first reacting at a temperature of -5 to 5°C for 1 to 2 hours, and then reacting at room temperature for 10 to 12 hours.

6. The method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 5, characterized in that: The polycondensation reaction is carried out in anhydrous N,N-dimethylacetamide.

7. The method for preparing a polyaromatic amide having a trifluoromethyl and carbazole modified triphenylamine structure according to claim 6, characterized in that: The amount of anhydrous N,N-dimethylacetamide used is to maintain the solid content of the polymerization system at 20-25%.

Images