Polybenzimidazole, polymer film, preparation method, and use

Abstract

The present invention relates to the technical field of polybenzimidazoles. Disclosed are a polybenzimidazole, a polymer film, a preparation method, and a use. The polybenzimidazole of the present invention comprises a structural unit A1 and a structural unit A2 and optionally comprises a structural unit B1 and a structural unit B2, wherein the structural unit A1 has a structure represented by formula (A1), the structural unit A2 has a structure represented by formula (A2), the structural unit B1 has a structure represented by formula (B1), and the structural unit B2 has a structure represented by formula (B2). The polybenzimidazole of the present invention has relatively high light transmittance and relatively low haze, and the film has relatively high elongation at break.

Description

Polybenzimidazole and polymer film, and preparation method and application thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of polybenzimidazole, and in particular to polybenzimidazole and polymer film, and preparation method and application thereof. BACKGROUND

[0002] Polybenzimidazole (PBI) is a kind of aromatic heterocyclic polymer containing benzimidazole repeating structural units in the main chain. Polybenzimidazole is a kind of special engineering plastic with excellent comprehensive performance, which has excellent high-temperature resistance, chemical stability and mechanical properties. The long-term use temperature of polybenzimidazole can reach 375℃, and the heat resistance is excellent, and it also has good mechanical strength. Polybenzimidazole can be used in extreme high-temperature, harsh chemical and plasma environments, or in application environments with high requirements for product durability and wear resistance.

[0003] The wavelength of ultraviolet light is short and the energy is high, which can easily cause chemical bond rupture and change the properties of the material, so ultraviolet radiation is one of the main reasons for material photoaging. Polybenzimidazole has good absorption of ultraviolet light and can be used as an ultraviolet light-absorbing film to absorb ultraviolet light and prolong the service life of the device. However, polybenzimidazole film is usually yellow-brown in color, which is relatively deep, so the light transmittance of polybenzimidazole film is poor, and its application in the optical field is greatly limited. Some fields with high requirements for transparency, such as flexible display, solar cell flexible backboard, etc. cannot use polybenzimidazole film materials.

[0004] Polybenzimidazole materials usually have low solubility, and homopolymerized polybenzimidazole also has the problem of excessive rigidity and regular arrangement of molecular chains, which leads to excessive rigidity and insufficient toughness of the material. Copolymerization can usually balance the performance of different structures and obtain materials with good comprehensive performance. However, due to the introduction of different structural molecular chain segments by copolymerization, the regular arrangement of molecular chains is usually affected, which further causes the optical performance of the material such as light transmittance and / or transparency to decrease. SUMMARY

[0005] The purpose of the present application is to overcome the problems of existing polybenzimidazole, such as deep color, low light transmittance and low toughness. The present application provides a kind of polybenzimidazole, polybenzimidazole film and its preparation method and application, wherein the polybenzimidazole film can maintain high light transmittance and good transparency while ensuring good mechanical properties, which expands the application field of polybenzimidazole.

[0006] To achieve the above object, the present application provides, in a first aspect, a polybenzimidazole comprising structural unit A1 and structural unit A2, and optionally comprising structural unit B1 and structural unit B2, wherein structural unit A1 has a structure shown in formula (A1), structural unit A2 has a structure shown in formula (A2), structural unit B1 has a structure shown in formula (B1), and structural unit B2 has a structure shown in formula (B2):

[0007] wherein R1 and R2 are each independently substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, any one of a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups spaced by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a divalent organic group consisting of 2-5 substituted or unsubstituted heterocyclylene groups spaced by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and R1 and R2 are not the same; and X1 and X2 are each independently fluorine-containing hydrocarbylene, and when structural unit B1 and structural unit B2 are present, X1 and X2 are not the same.

[0008] The present application provides, in a second aspect, a method for preparing a polybenzimidazole, the method comprising: polymerizing monomers in a first solvent under polymerization conditions;

[0009] wherein the monomers comprise monomer a1, monomer b, monomer c, and optionally monomer a2, the monomers a1 and a2 each independently have a structure shown in formula (1-1), the monomers b and c each independently have a structure shown in HOOC-R-COOH; monomer b and monomer c are not the same, and when monomer a2 is present, the X group in monomer a1 is different from the X group in monomer a2;

[0010] wherein R is selected from the group consisting of substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, a divalent organic radical consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a divalent organic radical consisting of 2-5 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; and X is selected from fluorine-containing hydrocarbylene.

[0011] The third aspect of the present application provides a polybenzimidazole prepared by the above-mentioned method.

[0012] The fourth aspect of the present application provides a polymer film containing the above-mentioned polybenzimidazole.

[0013] The fifth aspect of the present application provides a method for preparing a polymer film, which comprises: contacting the polybenzimidazole of the present application with a second solvent to obtain a solution A; preparing a liquid film from the solution A with or without solid-liquid separation; and drying the liquid film to obtain a polymer film.

[0014] The sixth aspect of the present application provides a polymer film prepared by the above-mentioned method.

[0015] The seventh aspect of the present application provides the above-mentioned polybenzimidazole and / or the above-mentioned polymer film as a light-transmitting or transparent material.

[0016] By the above technical solution, the present application can achieve the following beneficial effects:

[0017] (1) The polybenzimidazole of the present application has a light color, colorless transparency or near colorless transparency after being made into a film; has a high light transmittance and a low haze under a standard C light source, and the film has a high toughness (i.e. a high elongation at break); the polybenzimidazole of the present application can be used to prepare a film with high light transmittance, high transparency and high flexibility, thereby expanding the application field of polybenzimidazole.

[0018] (2) The polybenzimidazole of the present application has a good absorption capacity for ultraviolet light after being made into a film, which can delay the photoaging of a device.

[0019] (3) In some embodiments of the present application, the polybenzimidazole not only has a colorless transparent or almost colorless transparent appearance, a higher light transmittance, a lower haze and a higher toughness, but also has a higher viscosity average molecular weight, and good solubility performance, which is beneficial to subsequent processing application. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Example 1;

[0021] Figure 2 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Example 2 and Preparation Example 4;

[0022] Figure 3 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Example 5;

[0023] Figure 4 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Example 6;

[0024] Figure 5 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Example 7;

[0025] Figure 6 is a nuclear magnetic hydrogen spectrum of the polybenzimidazole prepared in Preparation Examples 8-11;

[0026] Figure 7 is a ultraviolet-visible spectrum of the polybenzimidazole film of Example 1-3 and Comparative Examples 1 and 2. DETAILED DESCRIPTION

[0027] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact values are understood to be within the range of values. Any numerical value, however, can be expressed as approximately or approximately.

[0028] The first aspect of the present application provides a polybenzimidazole comprising (repeating) structural unit A1 and (repeating) structural unit A2, and optionally comprising (repeating) structural unit B1 and (repeating) structural unit B2, wherein structural unit A1 has a structure shown in formula (A1), structural unit A2 has a structure shown in formula (A2), structural unit B1 has a structure shown in formula (B1), and structural unit B2 has a structure shown in formula (B2):

[0029] Wherein, R1 and R2 are each independently a substituted or unsubstituted arylene, a substituted or unsubstituted cycloalkylene, a substituted or unsubstituted alkylene subchain, a substituted or unsubstituted alkenyl, a substituted or unsubstituted heterocyclic subchain, or a divalent arylene consisting of 2-5 substituted or unsubstituted monocyclic arylene groups spaced apart by at least one of single bonds, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenyl, and substituted or unsubstituted C1-C5 alkylene. An organic group, and any one of the following: an organic group consisting of 2-5 substituted or unsubstituted heterocyclic groups spaced apart by at least one of single bonds, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenyl groups and substituted or unsubstituted C1-C5 alkylene groups, wherein R1 and R2 are not the same; and X1 and X2 are each independently fluorinated alkenyl groups, wherein X1 and X2 are different when structural units B1 and B2 are present.

[0030] According to the present invention, preferably, R1 and R2 are each independently substituted or unsubstituted C6-C. 24 arylene, substituted or unsubstituted C5-C 24 Cycloalkylene, substituted or unsubstituted C2-C 20 Sub-alkyl, substituted or unsubstituted C2-C 20 alkenyl, substituted or unsubstituted C3-C 20 The heterocyclic group, a divalent organic group consisting of 2-3 substituted or unsubstituted monocyclic aryl groups spaced apart by at least one of single bonds, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenyl groups and substituted or unsubstituted C1-C5 alkyl groups, and any one of the following:

[0031] In this invention, the substituted or unsubstituted aryl group can be a substituted or unsubstituted C6-C group. 24 aryl groups, such as substituted or unsubstituted C6-C 14 The arylene group may be a monocyclic or polycyclic arylene group. For example, the arylene group may be phenylene or naphthylene. When substituted, the substituent may be a hydroxyl group, a halogen (e.g., F, Cl, Br, and I), or a substituted or unsubstituted C1-C5 alkyl group; wherein the substituent in the C1-C5 alkyl group may be a halogen (e.g., F, Cl, Br, and I), such as trifluoromethyl-CF3.

[0032] In the present application, the substituted or unsubstituted cycloalkylene group can be a substituted or unsubstituted C5-C 24 cycloalkylene group, for example, a substituted or unsubstituted C5-C 10 cycloalkylene group. For example, the cycloalkylene group can include, but is not limited to, a substituted or unsubstituted cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, and the like. When substituted, the substituents of the cycloalkylene group can be a C1-C5 alkyl group or a C1-C5 alkyl group substituted with a halogen (e.g., F, CI, Br, and I), for example, a methyl group, an ethyl group, a trifluoromethyl group -CF3, and the like.

[0033] In the present application, the substituted or unsubstituted alkylene group can be a substituted or unsubstituted C2-C 20 alkylene group, for example, a substituted or unsubstituted C2-C 12 alkylene group. For example, the alkylene group can include, but is not limited to, a substituted or unsubstituted ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, and the like. When substituted, the substituents of the alkylene group can be a halogen (e.g., F, CI, Br, and I) or a substituted or unsubstituted C1-C5 alkyl group, wherein the substituents of the C1-C5 alkyl group can be a halogen (e.g., F, CI, Br, and I), for example, a trifluoromethyl group -CF3. For example, the substituted alkylene group can be a fluoro-substituted alkylene group, for example, -C(CF3)2-.

[0034] In the present application, the substituted or unsubstituted alkenylene group can be a substituted or unsubstituted C2-C 20 alkenylene group, for example, a substituted or unsubstituted C2-C 10 alkenylene group. For example, the alkenylene group can include, but is not limited to, a substituted or unsubstituted ethenylene group, a propenylene group, a butenylene group, and the like. When substituted, the substituents of the alkenylene group can be a halogen (e.g., F, CI, Br, and I), a substituted or unsubstituted C1-C5 alkyl group, or a substituted or unsubstituted phenyl group, wherein the substituents of the C1-C5 alkyl group can be a halogen (e.g., F, CI, Br, and I), for example, a trifluoromethyl group -CF3, and wherein the substituents of the phenyl group can be a halogen (e.g., F, CI, Br, and I) and the above-mentioned substituted or unsubstituted C1-C5 alkyl group.

[0035] In the present application, the substituted or unsubstituted heterocyclylene group can be a substituted or unsubstituted C3-C 20 heterocyclylene group, for example, a substituted or unsubstituted C3-C 10substituted or unsubstituted C1-C5 alkyl group; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3. In this case, the "substituted or unsubstituted C2-C5 alkenylene group" can be a substituted or unsubstituted C2-C5 alkenylene group. When substituted, the substituent can be a hydroxyl group, halogen (e.g., F, CI, Br, and I), or a substituted or unsubstituted C1-C5 alkyl group; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3. In this case, the R1and R2may each independently be one of the following divalent organic groups, for example:

[0036] In the present application, the R1and R2may each independently be a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3, and wherein the substituent of the C2-C5 alkenylene group can be a phenyl group. In this case, the "substituted or unsubstituted monocyclic arylene group" can be a substituted or unsubstituted phenylene group; when substituted, the substituent can be a hydroxyl group, halogen (e.g., F, CI, Br, and I), or a substituted or unsubstituted C1-C5 alkyl group; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3. In this case, the R1and R2may each independently be one of the following divalent organic groups, for example:

[0037] In the present application, the R1and R2may each independently be a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3, and wherein the substituent of the C2-C5 alkenylene group can be a phenyl group. In this case, the "substituted or unsubstituted monocyclic arylene group" can be a substituted or unsubstituted phenylene group; when substituted, the substituent can be a hydroxyl group, halogen (e.g., F, CI, Br, and I), or a substituted or unsubstituted C1-C5 alkyl group; wherein the substituent of the C1-C5 alkyl group can be halogen (e.g., F, CI, Br, and I), for example, trifluoromethyl group -CF3. In this case, the R1and R2may each independently be one of the following divalent organic groups, for example:

[0038] In the present application, more preferably, the heterocyclylene group can be selected from the group consisting of pyridylene, pyrrolylene, furanylene, quinolylene, thienylene, pyrylylene and pyrazinylene.

[0039] According to the present application, preferably, X1and X2are each independently a C1-C 10 fluorine-containing hydrocarbylene group; more preferably a C1-C5fluorine-containing hydrocarbylene group. In some embodiments, preferably, X1is -C(CF3)2-. In some embodiments, preferably, X1and X2are each -C(CF3)2-, i.e. in this case there are no structural units B1and B2.

[0040] According to the present application, in some embodiments, the polybenzimidazole does not comprise structural units B1and B2.

[0041] According to the present application, when the polybenzimidazole comprises structural units B1and B2, the ratio of the total number of moles of structural units A1and A2to the total number of moles of structural units B1and B2in the polymer can be any suitable ratio, for example can be 0.01 : 1 - 100 : 1.

[0042] According to the present application, preferably, R1and R2are each independently selected from the group consisting of the groups shown in formulae (3) - (24): wherein n is an integer from 2 to 8, for example n can be 2, 3, 4, 5, 6, 7 or 8.

[0043] According to the present application, preferably, R1is a group shown in formula (3) and R2is any one of the groups shown in formulae (4) - (24).

[0044] In some preferred embodiments, R1is a group shown in formula (3) and R2is any one of the groups shown in formulae (4), (13) and (24).

[0045] According to some preferred embodiments of the present application, the structural unit A1may be and the structural unit A2may be .

[0046] According to some more preferred embodiments of the present application, the structural unit A1may be and the structural unit A2may be .

[0047] According to the present application, preferably, the molar ratio of the structural unit A1 to the structural unit A2 can be 0.02:1-50:1, preferably 0.05:1-20:1. For example, the molar ratio of the structural unit A1 to the structural unit A2 can be 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.4:1, 0.5:1, 0.7:1, 1:1, 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 30:1, 40:1, 50:1, and a range consisting of any two of the above values.

[0048] According to the present application, preferably, the viscosity average molecular weight of the polybenzimidazole can be 2000-500000 g / mol; more preferably 10000-400000 g / mol; still more preferably 30000-400000 g / mol; for example, 40000-350000 g / mol or 100000-350000 g / mol. For example, the viscosity average molecular weight of the polybenzimidazole can be 2000 g / mol, 4000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, 10000 g / mol, 11000 g / mol, 12000 g / mol, 13000 g / mol, 14000 g / mol, 15000 g / mol, 16000 g / mol, 18000 g / mol, 20000 g / mol, 25000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol, 60000 g / mol, 70000 g / mol, 80000 g / mol, 90000 g / mol, 100000 g / mol, 120000 g / mol, 140000 g / mol, 160000 g / mol, 180000 g / mol, 200000 g / mol, 250000 g / mol, 300000 g / mol, 350000 g / mol, 400000 g / mol, 450000 g / mol, 500000 g / mol, and a range consisting of any two of the above values.

[0049] According to the present application, preferably, the polybenzimidazole has good solubility in a good solvent; wherein the good solvent can be selected from any one or several of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone.

[0050] According to the present application, preferably, 1.0 g of the polybenzimidazole of the present application is completely dissolved in 30 mL of dimethyl sulfoxide at 80°C and a stirring tip speed of 0.5 m / s in a time period of 0.3 to 8 h, preferably 0.3 to 4 h, more preferably 0.3 to 2 h. In the present application, the stirring tip speed is the linear speed of the tip of the stirring blade or rotor.

[0051] According to the present application, preferably, the polybenzimidazole has an intrinsic viscosity of 0.1 to 6.5 dL / g; preferably of 0.5 to 6 dL / g; for example of 2 to 5 dL / g. For example, the polybenzimidazole can have an intrinsic viscosity of 0.1 dL / g, 0.2 dL / g, 0.3 dL / g, 0.4 dL / g, 0.5 dL / g, 0.6 dL / g, 0.7 dL / g, 0.8 dL / g, 0.9 dL / g, 1 dL / g, 1.1 dL / g, 1.2 dL / g, 1.3 dL / g, 1.4 dL / g, 1.5 dL / g, 1.6 dL / g, 1.7 dL / g, 1.8 dL / g, 1.9 dL / g, 2.0 dL / g, 2.2 dL / g, 2.4 dL / g, 2.6 dL / g, 2.8 dL / g, 3.0 dL / g, 3.2 dL / g, 3.4 dL / g, 3.6 dL / g, 3.8 dL / g, 4.0 dL / g, 4.1 dL / g, 4.2 dL / g, 4.3 dL / g, 4.4 dL / g, 4.5 dL / g, 4.6 dL / g, 4.7 dL / g, 4.8 dL / g, 4.9 dL / g, 5.0 dL / g, 5.2 dL / g, 5.4 dL / g, 5.6 dL / g, 5.8 dL / g, 6.0 dL / g, 6.5 dL / g, and a range formed by any two of the aforementioned values.

[0052] The polybenzimidazole of the present application is a random copolymer, wherein the structural units A1 and A2, and optionally the structural units B1 and B2, are randomly distributed in the polybenzimidazole polymer chain.

[0053] The polybenzimidazole of the present application can be prepared by methods generally known in the art for preparing polybenzimidazoles. In some embodiments, preferably, the polybenzimidazole of the present application can be prepared by the method for preparing a polybenzimidazole according to the second aspect of the present application.

[0054] The second aspect of the present application provides a method for preparing a polybenzimidazole, the method comprising: polymerizing a monomer in a first solvent under polymerization conditions;

[0055] wherein the monomers include monomer a1, monomer b, monomer c, and optionally monomer a2, each of the monomers a1 and a2 independently has a structure represented by Formula (1-1), each of the monomers b and c independently has a structure represented by HOOC-R-COOH; monomer b is different from monomer c, and the X group in monomer a1 is different from the X group in monomer a2 when monomer a2 is present;

[0056] wherein R is selected from the group consisting of substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, a bivalent organic radical consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a bivalent organic radical consisting of 2-5 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; and X is a fluorine-containing hydrocarbylene group.

[0057] According to the present application, preferably, X is a C1-C 10 fluorine-containing hydrocarbylene group; more preferably a C1-C5 fluorine-containing hydrocarbylene group; further preferably, X is -C(CF3)2-.

[0058] According to the present application, preferably, R is selected from the group consisting of substituted or unsubstituted C6-C 24 arylene, substituted or unsubstituted C5-C 24 cycloalkylene, substituted or unsubstituted C2-C 20 alkylene, substituted or unsubstituted C2-C 20 alkenylene, substituted or unsubstituted C3-C 20 heterocyclylene, a bivalent organic radical consisting of 2-3 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a bivalent organic radical consisting of 2-3 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene.

[0059] In the present application, the substituted or unsubstituted arylene group, the substituted or unsubstituted cycloalkylene group, the substituted or unsubstituted alkylene group, the substituted or unsubstituted alkenylene group, the substituted or unsubstituted heterocyclic group and the divalent organic group in the above method are as described in the first aspect, which will not be repeated here.

[0060] According to the present application, preferably, R is selected from the group consisting of the groups represented by formula (3) to formula (24): wherein n is an integer from 2 to 8, for example, n can be 2, 3, 4, 5, 6, 7 or 8.

[0061] According to the present application, preferably, R in monomer b is the group represented by formula (3) and R in monomer c is any one of the groups represented by formula (4) to formula (24).

[0062] According to the present application, more preferably, R in monomer b is the group represented by formula (3) and R in monomer c is any one of the groups represented by formula (4), formula (13) and formula (24).

[0063] According to the present application, preferably, HOOC-R-COOH is selected from the group consisting of compounds represented by formula (3-1) to formula (24-1); wherein n is an integer from 2 to 8, for example, n can be 2, 3, 4, 5, 6, 7 or 8.

[0064] According to the present application, preferably, monomer b is at least one of the compounds represented by formula (3-1) and monomer c is at least one of the compounds represented by formula (4-1) to formula (24-1).

[0065] According to the present application, more preferably, monomer b is the compound represented by formula (3-1) and monomer c is the compound represented by formula (4-1), formula (13-1) or formula (24-1).

[0066] According to the present application, preferably, the molar ratio of the total amount of monomers b and c to the amount of monomers a1 and a2 is 0.9:1 to 1.1:1, for example, 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1, and a range formed by any two of the above.

[0067] According to the present application, preferably, the molar ratio of the amount of monomer b and monomer c is 0.02:1-50:1, more preferably 0.05-20:1; for example, the molar ratio of the amount of monomer b and monomer c can be 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.4:1, 0.5:1, 0.7:1, 1:1, 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 30:1, 40:1, 50:1, and a range formed by any two of the above.

[0068] According to the present application, the conditions of the polymerization reaction can be conventional polymerization reaction conditions in the art. Preferably, the conditions of the polymerization reaction can include: the temperature of the polymerization is 100-220℃ (for example, 100℃, 110℃, 120℃, 140℃, 160℃, 180℃, 200℃, 220℃, and a range formed by any two of the above), and the time of the polymerization is 1-24h (for example, 1h, 2h, 4h, 5h, 6h, 7h, 8h, 10h, 15h, 20h, 24h, and a range formed by any two of the above). Preferably, the polymerization reaction is carried out under stirring.

[0069] According to the present application, preferably, the polymerization reaction is carried out under a non-reactive atmosphere. For example, the non-reactive atmosphere can be provided by at least one of nitrogen, argon, helium and neon, preferably nitrogen.

[0070] According to the present application, preferably, the first solvent can include at least one of polyphosphoric acid, methanesulfonic acid, phosphorus pentoxide and phosphoric acid.

[0071] According to the present application, preferably, the amount of the first solvent is 2-20kg per 1mol of monomers a1 and a2, for example, can be 2kg, 4kg, 6kg, 8kg, 10kg, 15kg, 20kg, and a range formed by any two of the above.

[0072] In the method of the present application, a polymer solution is obtained after the polymerization is completed. According to the present application, the method can further comprise a step of extracting the polymer from the polymer solution obtained after the polymerization. The way of extracting the polymer can be any way commonly used in the art. For example, the method can further comprise a step of contacting the solution containing polybenzimidazole obtained after the polymerization with a precipitant to obtain polybenzimidazole as a precipitate. In this case, the precipitant can be water and / or a basic solution. The basic solution can be at least one of an aqueous solution of an alkali metal hydroxide, an aqueous solution of an alkaline earth metal hydroxide, an aqueous solution of an alkali metal salt, an aqueous solution of an alkaline earth metal salt, and aqueous ammonia; and is further preferably at least one of aqueous ammonia, a saturated aqueous sodium carbonate solution, an aqueous potassium carbonate solution, an aqueous sodium bicarbonate solution, an aqueous potassium bicarbonate solution, an aqueous magnesium carbonate solution, an aqueous sodium hydroxide solution, and an aqueous potassium hydroxide solution. Then, the obtained polybenzimidazole can be washed with a basic solution and / or water, for example, to be neutral. Then, the obtained polybenzimidazole can be dried, for example, by being heated in a vacuum oven. For example, the polybenzimidazole can be placed in a vacuum oven at 40-120°C for 2-48h, for example, the polybenzimidazole can be placed in a vacuum oven at 80°C for 24h.

[0073] The third aspect of the present application provides a polybenzimidazole prepared by the above-mentioned method. In some preferred embodiments, the polybenzimidazole of the first aspect of the present application is prepared by the above-mentioned method.

[0074] The fourth aspect of the present application provides a polymer film containing a polybenzimidazole, wherein the polybenzimidazole is the above-mentioned polybenzimidazole. In the present application, the polymer film can be in the form of a planar film. The thickness of the film can be appropriately selected by those skilled in the art, for example, the thickness of the film can be several nanometers to several millimeters. In some embodiments, the thickness of the polymer film of the present application can be, for example, 0.02 micrometers to 0.5 millimeters.

[0075] According to the present application, preferably, the elongation at break of the polymer film can be 5-100%, preferably 6-80%. In some embodiments, more preferably, the elongation at break of the polymer film can be 8-60%, preferably 20-50%. For example, the elongation at break of the polymer film can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 14%, 16%, 18%, 20%, 22%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 80%, 90%, 100%, and any range formed by any two of the above values.

[0076] According to the present application, the polymer film can have a light transmittance of 70-95%, preferably 75-95%, more preferably 80-95%, still more preferably 83-90%, for example 84-90%. For example, the polymer film can have a light transmittance of 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, and a range between any two of the aforementioned values. According to the present application, the polymer film can have a haze of 0.05-20%, preferably 0.1-16%, more preferably 0.2-8% or 0.3-6%. For example, the polymer film can have a haze of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and a range between any two of the aforementioned values. In the present application, the light transmittance and haze values are obtained by using a light transmittance-haze meter according to GB / T 2410-2008 standard with a standard C light source and a film of 25 microns in thickness.

[0077] In the present application, the thickness of the film is obtained by testing the thickness at 5 points on the film using a thickness gauge and taking the arithmetic mean.

[0078] According to the present application, the polymer film can further comprise an inorganic additive and / or a polymer additive. Preferably, the inorganic additive can comprise at least one of nano-silica, nano-titania, graphene, nano-tin oxide, carbon nanotube, fullerene, and nano-zirconium oxide. Preferably, the polymer additive can comprise at least one of polyimide, polysulfone, polyether ether ketone, polybenzoxazole, polyethylene terephthalate, ethylene-vinyl alcohol copolymer, polyolefin elastomer, polyethylene glycol, and polyethylene oxide.

[0079] According to the present application, preferably, the content of the inorganic additive can be 0-10 parts by weight and the content of the polymer additive can be 0-100 parts by weight with respect to 100 parts by weight of the polybenzimidazole.

[0080] The polymer film of the present application can be prepared by a method commonly known in the art for preparing a film. In some embodiments, the polymer film can be prepared by preparing a solution of polybenzimidazole; preparing a liquid film from the solution A; and drying the liquid film to obtain a polymer film.

[0081] The fifth aspect of the present application provides a method for preparing a polymer film, the method comprising: contacting the polybenzimidazole described above with a second solvent to obtain a solution A; preparing a liquid film from the solution A with or without solid-liquid separation; and drying the liquid film to obtain the polymer film.

[0082] In the present application, the solution A can be subjected to solid-liquid separation and then the filtrate is used to prepare a liquid film, or the solution A can be directly prepared into a liquid film without solid-liquid separation. Those skilled in the art can reasonably choose whether to perform solid-liquid separation according to the solid content and dissolution of the solution A.

[0083] According to the present application, preferably, the second solvent can include at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl pyrrolidone, methanesulfonic acid, formic acid, phosphoric acid, polyphosphoric acid, sulfuric acid, and trichloromethylbenzene.

[0084] According to the present application, preferably, the content of the polybenzimidazole can be 0.1-20% by weight based on the total weight of the solution A. In some embodiments, the content of the polybenzimidazole in the solution A can be 0.1%, 0.2%, 0.4%, 0.6%, 1%, 2%, 3%, 4%, 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, or a range consisting of any two of the above values.

[0085] According to the present application, preferably, the conditions of the contacting can include: the temperature of the contacting is 30-160°C (for example, 30°C, 50°C, 60°C, 80°C, 100°C, 140°C, 160°C, and a range consisting of any two of the above values), and the time of the contacting is 10 min-24 h (10 min, 30 min, 1 h, 2 h, 3 h, 4 h, 10 h, 20 h, 24 h, and a range consisting of any two of the above values). The contacting can be performed under stirring, preferably, the linear speed of the stirring is 0.05-1 m / s, more preferably, 0.1-0.8 m / s.

[0086] In the present application, the method of solid-liquid separation can be a method commonly used in the art, for example, filtration. Preferably, the method of solid-liquid separation is sand core funnel filtration; more preferably, the pore size of the sand core funnel is 30-50 μm.

[0087] In the present application, the liquid film can be prepared by any method known in the art, including but not limited to, doctor blading, spraying, slot-die coating, natural flow, and the like. For example, the solution, with or without solid-liquid separation, can be poured on a substrate, and then a liquid film can be formed by doctor blading. The substrate can be selected from rigid substrates such as glass plate, stainless steel plate, polytetrafluoroethylene plate, and the like; or flexible substrates such as polyimide film, polyethylene terephthalate film, polysulfone film, cellulose film, non-woven fabric, and the like.

[0088] In the present application, after the liquid film is obtained, the liquid film can be dried. The conditions for drying the liquid film can be suitably selected by those skilled in the art. According to the present application, preferably, the conditions for drying can include a temperature of 60-160°C and a time of 0.5-24h. In some embodiments, the drying can be performed in air.

[0089] According to the present application, preferably, the method can further include contacting an inorganic additive and / or a polymeric additive with a second solvent to obtain a solution B, mixing the solution B with the solution A to obtain a solution C, and then preparing a liquid film from the solution C after solid-liquid separation, and drying the liquid film to obtain a polymer film. The inorganic additive and / or the polymeric additive can be the inorganic additive and / or the polymeric additive mentioned in the fourth aspect of the present application, which will not be repeated here. In this way, a polymer film further comprising the inorganic additive and / or the polymeric additive can be prepared.

[0090] According to the present application, preferably, the conditions for contacting the inorganic additive and / or the polymeric additive with the second solvent can include a temperature of 30-160°C and a time of 0.5-24h. The contacting can be performed by stirring and / or ultrasonic treatment.

[0091] According to the present application, optionally, in some embodiments, a cosolvent can be added when preparing the solution A to facilitate the dissolution of polybenzimidazole. The cosolvent can be selected from any one or more of lithium chloride, sodium chloride, lithium trifluoromethanesulfonimide, and the like.

[0092] The sixth aspect of the present application provides a polymer film prepared by the method described above.

[0093] The polybenzimidazole of the present application and the polymer film of the present application have good light transmittance and transparency, and can have good mechanical properties including tensile strength and / or elongation at break. Therefore, the seventh aspect of the present application provides the use of the polybenzimidazole described above and / or the polymer film described above as a light-transmitting or transparent material.

[0094] According to the present application, preferably, the light-transmitting or transparent material includes, but is not limited to, a flexible backsheet of a solar cell, a flexible display substrate, a security packaging, a high-temperature resistant transparent component of an electronic device / sensor, a high-temperature resistant optical lens, a high-temperature protective mask, a flexible printed circuit, and a cockpit protective cover of an airplane.

[0095] Embodiment

[0096] The present application is described in detail below by way of examples. In the following examples, the raw materials are all commercially available.

[0097] 3,3'-diaminobenzidine (Sigma-Aldrich, 99%); 2,2-bis(3,4-diaminophenyl)hexafluoropropane (CAS No.: 61005-79-6, RunTu New Material Co., Ltd., Henan, China, 98%); 4,4-dicarboxy diphenyl ether (J&K Scientific, 98%); isophthalic acid (J&K Scientific, 98%); cyclohexanedicarboxylic acid (Beijing Inokai Technology Co., Ltd., 98%); azelaic acid (Beijing Inokai Technology Co., Ltd., 98%); 3,5-pyridinedicarboxylic acid (J&K Scientific, 97%); 4,4'-methylene bisbenzoic acid (Angene, 98%); 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid (Angene, 98%); methanesulfonic acid (J&K Scientific, 98%); phosphorus pentoxide (J&K Scientific, 98%); sodium carbonate (J&K Scientific, 98%); N,N-dimethylacetamide (Beijing Inokai Technology Co., Ltd., 99.5%); dimethyl sulfoxide (J&K Scientific, 98%).

[0098] All reagents were used directly without secondary purification.

[0099] The molar ratio of structural unit A1 and structural unit A2 in the polybenzimidazole was obtained by quantitative analysis of nuclear magnetic hydrogen spectrum. The specific test method is: testing on a nuclear magnetic resonance spectrometer (Bruke DMX400, deuterated reagent d 4 -CH3OH, tetramethylsilane (TMS) as internal standard) and obtaining the molar ratio of structural unit A1 and structural unit A2 according to the peak area ratio of the characteristic peaks of structural unit A1 and structural unit A2.

[0100] Preparation Example 1

[0101] This preparation example is used to illustrate the preparation process of polybenzimidazole.

[0102] Under nitrogen atmosphere, polyphosphoric acid (60 g), 2,2-bis(3,4-diaminophenyl)hexafluoropropane (10 mmol), 4,4-dicarboxy diphenyl ether (8 mmol), isophthalic acid (2 mmol) were added into a reactor, and the reaction was carried out at 200°C for 4 h under stirring. After the reaction was completed, the reaction solution was poured into saturated aqueous sodium bicarbonate solution to precipitate the polymer, which was then repeatedly washed with water and sodium bicarbonate solution until neutral, and then was placed in a vacuum oven at 80°C for 24 h to obtain polybenzimidazole.

[0103] The structural formula of the structural unit A1 in the prepared polybenzimidazole is The structural formula of the structural unit A2 is

[0104] The nuclear magnetic hydrogen spectrum of the polybenzimidazole is shown in Figure 1, and the molar ratio of the structural unit A1 to the structural unit A2 calculated from the nuclear magnetic hydrogen spectrum of the polybenzimidazole is 4.465:1.

[0105] Preparation Example 2

[0106] This preparation example is used to illustrate the preparation process of polybenzimidazole.

[0107] Under nitrogen atmosphere, methanesulfonic acid (54 g), phosphorus pentoxide (5 g), 2,2-bis(3,4-diaminophenyl)hexafluoropropane (10 mmol), cyclohexanedicarboxylic acid (2 mmol), 4,4-dicarboxy diphenyl ether (8 mmol) were added into a reactor, and the reaction was carried out at 140°C for 6 h under stirring. After the reaction was completed, the reaction solution was poured into saturated aqueous sodium bicarbonate solution to precipitate the polymer, which was then repeatedly washed with water and sodium bicarbonate solution until neutral, and then was placed in a vacuum oven at 80°C for 24 h.

[0108] The structural formula of the structural unit A1 in the prepared polybenzimidazole is The structural formula of the structural unit A2 is

[0109] The nuclear magnetic hydrogen spectrum of the polybenzimidazole is shown in Figure 2, and the molar ratio of the structural unit A1 to the structural unit A2 calculated from the nuclear magnetic hydrogen spectrum of the polybenzimidazole is 2.817:1.

[0110] Preparation Example 3

[0111] Polybenzimidazole was prepared according to the method of Preparation Example 2, except that the amount of cyclohexanedicarboxylic acid was 1 mmol and the amount of 4,4-dicarboxy diphenyl ether was 9 mmol.

[0112] The proton nuclear magnetic resonance spectrum of the polybenzimidazole was similar to that of Preparation Example 2 and is not shown. The molar ratio of structural unit A1 to structural unit A2 was calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole to be 3.657:1.

[0113] Preparation Example 4

[0114] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that "2 mmol of cyclohexanedicarboxylic acid" was replaced with "7 mmol of azelaic acid", and the amount of 4,4-dicarboxy diphenyl ether was 3 mmol.

[0115] The structural formula of structural unit A1 in the prepared polybenzimidazole was The structural formula of structural unit A2 was

[0116] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in FIG. 2. The molar ratio of structural unit A1 to structural unit A2 was calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole to be 0.524:1.

[0117] Preparation Example 5

[0118] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that "2 mmol of cyclohexanedicarboxylic acid" was replaced with "5 mmol of 4,4'-(2,2-diphenylvinyl-1,1-diyl)dibenzoic acid", and the amount of 4,4-dicarboxy diphenyl ether was 5 mmol. The reaction temperature was 120°C, and the reaction time was 4 hours.

[0119] The structural formula of structural unit A1 in the prepared polybenzimidazole was The structural formula of structural unit A2 was

[0120] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in FIG. 3. The molar ratio of structural unit A1 to structural unit A2 was calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole to be 1.028:1.

[0121] Preparation Example 6

[0122] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that "8 mmol of 4,4-dicarboxy diphenyl ether" was replaced with "1 mmol of 3,5-pyridinedicarboxylic acid", and the amount of isophthalic acid was 9 mmol; and the reaction time was 6 hours.

[0123] The structural formula of structural unit A1 in the prepared polybenzimidazole was The structural formula of structural unit A2 was

[0124] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in Figure 4. The molar ratio of structural unit A1 to structural unit A2 calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole is 0.09:1.

[0125] Preparation Example 7

[0126] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that "8 mmol 4,4-dicarboxy diphenyl ether" was replaced by "1 mmol 2,2'-bipyridine-4,4'-dicarboxylic acid", and the amount of isophthalic acid was 9 mmol; the reaction time was 8 h.

[0127] The structural formula of structural unit A1 in the prepared polybenzimidazole is The structural formula of structural unit A2 is

[0128] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in Figure 5. The molar ratio of structural unit A1 to structural unit A2 calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole is 1.08:1.

[0129] Preparation Example 8

[0130] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that "8 mmol 4,4-dicarboxy diphenyl ether" was replaced by "1 mmol 2,2'-bipyridine-4,4'-dicarboxylic acid", and the amount of isophthalic acid was 9 mmol; the reaction time was 8 h.

[0131] The structural formula of structural unit A1 in the prepared polybenzimidazole is The structural formula of structural unit A2 is

[0132] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in Figure 5. The molar ratio of structural unit A1 to structural unit A2 calculated from the proton nuclear magnetic resonance spectrum of the polybenzimidazole is 1.08:1.

[0133] Preparation Example 9

[0134] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that "8 mmol 4,4-dicarboxy diphenyl ether" was replaced by "8 mmol azelaic acid", and the reaction temperature was 120°C and the reaction time was 6 h.

[0135] The structural formula of structural unit A1 in the prepared polybenzimidazole is The structural formula of structural unit A2 is

[0136] The proton nuclear magnetic resonance spectrum of the polybenzimidazole is shown in Figure 6.

[0137] Preparation Example 10

[0138] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that "2 mmol cyclohexanedicarboxylic acid" was replaced by "2 mmol perfluorooctanoic acid", and the reaction temperature was 120 °C and the reaction time was 6 h.

[0139] The structural formula of the structural unit A1 in the prepared polybenzimidazole was The structural formula of the structural unit A2 was

[0140] The proton magnetic resonance spectrum of the polybenzimidazole is shown in Figure 6.

[0141] Preparation Example 11

[0142] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that "8 mmol 4,4-dicarboxy diphenyl ether" was replaced by "3 mmol 2,2'-bis(4-carboxyphenyl) hexafluoropropane", and the amount of isophthalic acid was 7 mmol; and the reaction time was 8 h.

[0143] The structural formula of the structural unit A1 in the prepared polybenzimidazole was The structural formula of the structural unit A2 was

[0144] The proton magnetic resonance spectrum of the polybenzimidazole is shown in Figure 6.

[0145] Comparative Preparation Example 1

[0146] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that "2,2-bis(3,4-diaminophenyl) hexafluoropropane" was replaced by equimolar "3,3'-diaminobenzidine".

[0147] Comparative Preparation Example 2

[0148] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that "2,2-bis(3,4-diaminophenyl) hexafluoropropane" was replaced by equimolar "3,3'-diaminobenzidine".

[0149] Comparative Preparation Example 3

[0150] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that the amount of cyclohexanedicarboxylic acid was 10 mmol, and no 4,4-dicarboxy diphenyl ether was added.

[0151] Comparative Preparation Example 4

[0152] The polybenzimidazole was prepared according to the method of Preparation Example 2, except that the amount of 4,4-dicarboxy diphenyl ether was 10 mmol, and no isophthalic acid was added.

[0153] Comparative Preparation Example 5

[0154] The polybenzimidazole was prepared according to the method of Preparation Example 1, except that the amount of isophthalic acid was 10 mmol and 4,4-dicarboxy diphenyl ether was not added.

[0155] Comparative Preparation Example 6

[0156] The polybenzimidazole was prepared according to the method of Comparative Preparation Example 4, except that "2,2-bis(3,4-diaminophenyl)hexafluoropropane" was replaced with an equimolar amount of "3,3'-diaminobenzidine".

[0157] Comparative Preparation Example 7

[0158] The polybenzimidazole was prepared according to the method of Comparative Preparation Example 5, except that "2,2-bis(3,4-diaminophenyl)hexafluoropropane" was replaced with an equimolar amount of "3,3'-diaminobenzidine".

[0159] Comparative Preparation Example 8

[0160] The polybenzimidazole was prepared according to the method of Comparative Preparation Example 3, except that "2,2-bis(3,4-diaminophenyl)hexafluoropropane" was replaced with an equimolar amount of "3,3'-diaminobenzidine".

[0161] Comparative Preparation Example 9

[0162] The polybenzimidazole was prepared according to the method of Comparative Preparation Example 3, except that "2,2-bis(3,4-diaminophenyl)hexafluoropropane" was replaced with an equimolar amount of "3,3'-diaminobenzidine" and "cyclohexanedicarboxylic acid" was replaced with an equimolar amount of "2,2'-bis(4-carboxyphenyl)hexafluoropropane".

[0163] Test Example 1

[0164] The intrinsic viscosity and viscosity average molecular weight of the polybenzimidazole (PBI) prepared in the Test Preparation Example and Comparative Preparation Examples were tested; the test results are shown in Table 1.

[0165] (1) Test method for intrinsic viscosity: PBI powder was dissolved in concentrated sulfuric acid (98 wt%) to prepare a sulfuric acid solution having a concentration of 0.6 g / dL. The sulfuric acid solution was added to an Ubbelohde viscometer having a capillary inner diameter of 1.0-1.1 mm, and was stabilized in a 25°C constant-temperature water bath for 30 min; the outflow time of the solution was recorded as t1, the outflow time of the concentrated sulfuric acid was recorded as t0, and the concentration of the polymer solution was recorded as C. The intrinsic viscosity of the PBI was calculated according to Equation 1 and Equation 2.

[0166] Inherent viscosity

[0167] Inherent viscosity

[0168] The viscosity-average molecular weight M of the polymer is converted from the Mark-Houwink-Sakurada equation (Equation 3), where the constants K = 1.94 x 10 -4 , and a = 0.791. [η] = KM α Equation 3

[0169] (2) Test method for initial decomposition temperature: A Netzsch STA409PC thermal analyzer was used to test the sample; the test atmosphere was N2 atmosphere, the flow rate was 50 mL / min; the heating rate was 10 K / min, and the scanning range was 298-1273 K.

[0170] (3) Test method for dissolution time: 1 g of polybenzimidazole sample was dispersed in 30 mL of dimethyl sulfoxide, and dissolved at 80°C under stirring at a stirring linear speed of 0.5 m / s, and the time for complete dissolution was tested.

[0171] Table 1

[0172] Example 1

[0173] This example is used to illustrate the preparation process of a polybenzimidazole film.

[0174] (1) 1 g of polybenzimidazole prepared in Preparation Example 1 was added to 30 mL of dimethyl sulfoxide, and stirred at 80°C for 2 h to dissolve the polybenzimidazole to obtain a solution, wherein the linear speed of stirring was 0.31 m / s.

[0175] (2) The solution was filtered using a sand core funnel with a G2 aperture (aperture of 30-50 μm) to obtain a filtrate, and then the filtrate was poured onto a glass plate and scraped using a doctor blade to form a uniform liquid film on the glass plate.

[0176] (3) The glass plate with the liquid film was dried at 80°C for 12 h to obtain a polybenzimidazole film.

[0177] Example 2

[0178] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Preparation Example 2.

[0179] Example 3

[0180] A polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with an equal weight of the polybenzimidazole of Preparation Example 3.

[0181] Example 4

[0182] A polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with an equal weight of the polybenzimidazole of Preparation Example 4.

[0183] Example 5

[0184] A polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with an equal weight of the polybenzimidazole of Preparation Example 5.

[0185] Example 6

[0186] A polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with an equal weight of the polybenzimidazole of Preparation Example 6.

[0187] Example 7

[0188] A polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with an equal weight of the polybenzimidazole of Preparation Example 7.

[0189] Example 8

[0190] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Preparation Example 8.

[0191] Example 9

[0192] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Preparation Example 9.

[0193] Example 10

[0194] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Preparation Example 10.

[0195] Example 11

[0196] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Preparation Example 10.

[0197] Comparative Example 1

[0198] A polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with an equal weight of the polybenzimidazole of Comparative Preparation Example 1, and a cosolvent lithium chloride (5% by mass of the polybenzimidazole material) was added when preparing the polybenzimidazole solution in step (1), and the dissolving time was 3 h.

[0199] When no co-solvent was added to the polybenzimidazole solution prepared in Comparative Example 1, the polybenzimidazole was still not dissolved and had a large amount of powdery particles that were not visibly swollen after 8 hours. After the addition of the co-solvent, the solution was in a semi-gel state after 1 hour.

[0200] Comparative Example 2

[0201] The polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with the same weight of the polybenzimidazole of Comparative Preparation Example 2, and the polybenzimidazole solution was prepared by adding the co-solvent lithium chloride (8% by weight of the polybenzimidazole material) in step (1), and the dissolution time was 5 hours.

[0202] When no co-solvent was added to the polybenzimidazole solution prepared in Comparative Example 2, the polybenzimidazole was difficult to dissolve. After the addition of the co-solvent, the dissolution time was long.

[0203] Comparative Example 3

[0204] The polybenzimidazole film was prepared according to the method of Example 2, except that the polybenzimidazole of Preparation Example 2 was replaced with the same weight of the polybenzimidazole of Comparative Preparation Example 3.

[0205] However, the polybenzimidazole of Comparative Preparation Example 3 had poor film-forming properties, and could not form a large-area self-supporting film, and the film was easily broken, so that the mechanical properties could not be tested.

[0206] Comparative Examples 4-7

[0207] The polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with the same weight of the polybenzimidazole of Comparative Preparation Examples 4-7.

[0208] Comparative Example 8

[0209] The polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with the same weight of the polybenzimidazole of Comparative Preparation Example 8.

[0210] However, the polybenzimidazole of Comparative Preparation Example 8 had a small molecular weight, and could not form a large-area self-supporting film, and the film was easily broken, so that the mechanical properties could not be tested.

[0211] Comparative Example 9

[0212] The polybenzimidazole film was prepared according to the method of Example 1, except that the polybenzimidazole of Preparation Example 1 was replaced with the same weight of the polybenzimidazole of Comparative Preparation Example 9.

[0213] The film prepared from the polybenzimidazole of Comparative Preparation Example 9 was easily broken, and the mechanical properties were not tested.

[0214] Test Example 2

[0215] The light transmittance, haze, elongation at break, tensile strength, tensile modulus of the polybenzimidazole film were tested, and the test results are shown in Table 2.

[0216] (1) Test of light transmittance and haze: tested by WGT-S light transmittance / haze tester (Shanghai Shen Guang Instrument and Meter Co., Ltd.) using standard C light source according to GB / T 2410-2008 standard. The light transmittance and haze values of the polybenzimidazole sample film with a thickness of about 25 microns were selected for testing and are shown in Table 2.

[0217] (2) Test of mechanical properties: the film was cut into a 4*1 cm rectangular sample for testing the mechanical properties. In an environment of room temperature (25±2) ℃ and humidity (50±10) %, the initial distance between the upper and lower clamps was 15 mm, and the mechanical properties (elongation at break, tensile strength, tensile modulus) of the film sample were tested by using a 5965 type universal tensile tester of Instron, USA at a tensile rate of 1 mm / min.

[0218] (3) Test of UV-Vis spectrum of the polybenzimidazole film: tested using a UV-Vis-near infrared spectrometer (UV3600 spectrophotometer, Japan Shimadzu).

[0219] Table 2

[0220] The UV-Vis absorption of the polybenzimidazole films of Examples 1-3 and Comparative Examples 1 and 2 is shown in Figure 7. As can be seen from Figure 7, in the ultraviolet light band, almost all the ultraviolet light is absorbed. Compared with the polybenzimidazole of Comparative Examples 1 and 2, the polybenzimidazole of Examples 1-3 of the present application maintains high light transmittance in the visible light band of >400 nm; while Comparative Examples 1 and 2 exhibit low light transmittance in the visible light band.

[0221] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A polybenzimidazole characterized by, The polybenzimidazole includes structural unit A1 and structural unit A2, and optionally includes structural unit B1 and structural unit B2, wherein structural unit A1 has a structure represented by formula (A1), structural unit A2 has a structure represented by formula (A2), structural unit B1 has a structure represented by formula (B1), and structural unit B2 has a structure represented by formula (B2): wherein R1and R2are each independently substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, any one of a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a divalent organic group consisting of 2-5 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and R1is not the same as R2; and X1and X2are each independently fluorine-containing hydrocarbylene, and when structural unit B1and structural unit B2are present, X1is not the same as X2.

2. The polybenzimidazole of claim 1, wherein, R1and R2are each independently substituted or unsubstituted C6-C 24 arylene, substituted or unsubstituted C5-C 24 cycloalkylene, substituted or unsubstituted C2-C 20 alkylene, substituted or unsubstituted C2-C 20 alkenylene, substituted or unsubstituted C3-C 20 heterocyclylene, a divalent organic radical consisting of 2-3 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5alkenylene, and substituted or unsubstituted C1-C5alkylene, and a divalent organic radical consisting of 2-3 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5alkenylene, and substituted or unsubstituted C1-C5alkylene; and X1and X2are each independently C1-C 10 fluorine-containing hydrocarbylene group of formula Preferably, the heterocyclylene is selected from the group consisting of pyridylene, pyrrolylene, furanylene, quinolylene, thienylene, pyranylene, and pyrazinylene.

3. The polybenzimidazole according to any one of claims 1-2, wherein, R1and R2are each independently selected from the group consisting of the groups represented by formula (3) to formula (24): wherein n is an integer from 2 to 8; Preferably, R1is any one of a group consisting of a group represented by formula (3) and a group represented by any one of formula (4) to formula (24); More preferably, R1is any one of a group consisting of a group represented by formula (3) and a group represented by any one of formula (4), formula (13), and formula (24).

4. The polybenzimidazole according to any one of claims 1 to 3, wherein, The molar ratio of the structural unit A1to the structural unit A2is 0.02:1 to 50:1, preferably 0.05:1 to 20:1; and / or The polybenzimidazole has a viscosity average molecular weight of 2000 to 500000 g / mol; preferably 10000 to 400000 g / mol; more preferably 30000 to 400000 g / mol; and / or The polybenzimidazole has an intrinsic viscosity of 0.1 to 6.5 dL / g; preferably 0.5 to 6 dL / g.

5. A process for the preparation of polybenzimidazole characterized in that, The method comprises: polymerizing the monomers in a first solvent under polymerization conditions; wherein the monomers comprise monomer a1, monomer b, monomer c, and optionally monomer a2; wherein each of the monomers a1 and a2 independently has the structure shown in formula (1-1); each of the monomers b and c independently has the structure shown in HOOC-R-COOH; monomers b and c are different, and the X group in monomer a1 is different from the X group in monomer a2 when monomer a2 is present; wherein R is selected from the group consisting of substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a divalent organic group consisting of 2-5 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; and X is a fluorine-containing hydrocarbylene; wherein R is selected from the group consisting of substituted or unsubstituted arylene, substituted or unsubstituted cycloalkylene, substituted or unsubstituted alkylene, substituted or unsubstituted alkenylene, substituted or unsubstituted heterocyclylene, a divalent organic group consisting of 2-5 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene, and a divalent organic group consisting of 2-5 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -O-, -C(=O)-, -S(=O)-, -SO2-, substituted or unsubstituted C2-C5 alkenylene, and substituted or unsubstituted C1-C5 alkylene; and X is a fluorine-containing hydrocarbylene; R is selected from the group consisting of substituted or unsubstituted C6-C 24 arylene, substituted or unsubstituted C5-C 24 cycloalkylene, substituted or unsubstituted C2-C 20 alkylene, substituted or unsubstituted C2-C 20 alkenylene, substituted or unsubstituted C3-C 20 heterocyclylene, a divalent organic radical consisting of 2-3 substituted or unsubstituted monocyclic arylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5alkenylene, and substituted or unsubstituted C1-C5alkylene, and a divalent organic radical consisting of 2-3 substituted or unsubstituted heterocyclylene groups separated by at least one of a single bond, -0-, -C(=0)-, -S(=0)-, -SO2-, substituted or unsubstituted C2-C5alkenylene, and substituted or unsubstituted C1-C5alkylene; and X is a C1-C 10 fluorine-containing hydrocarbylene.

6. The method of claim 5, wherein, R is selected from the group consisting of the radicals of formulae (3) to (24): wherein n is an integer from 2 to 8; Preferably, R in monomer b is any one of the group consisting of formula (3) and R in monomer c is any one of the group consisting of formula (4) to formula (24); More preferably, R in monomer b is any one of the group consisting of formula (3) and R in monomer c is any one of the group consisting of formula (4), formula (13) and formula (24).

7. The method of claim 5 or 6, wherein, The molar ratio of the total amount of monomer b and monomer c to the total amount of monomer a1 and monomer a2 is 0.9:1 to 1.1:1; and / or The molar ratio of the amount of monomer b to the amount of monomer c is 0.02:1 to 50:1, preferably 0.05:1 to 20:1; and / or The conditions of the polymerization reaction include that the temperature of the polymerization is 100 to 220°C and the time of the polymerization is 1 to 24 hours; and / or The polymerization reaction is carried out under a non-reactive atmosphere; and / or The first solvent includes at least one of polyphosphoric acid, methanesulfonic acid, phosphorus pentoxide and phosphoric acid; and / or The amount of the first solvent is 2 to 20 kg per 1 mol of monomer a1 and monomer a2.

8. A polybenzimidazole prepared by the method of any one of claims 5 to 7. The polymer film contains the polybenzimidazole of any one of claims 1 to 4 and 8. The elongation at break of the polymer film is 5 to 100%, preferably 6 to 80%, more preferably 8 to 60%, further more preferably 20 to 50%; and / or 9. A polymer film, characterized by, The light transmittance of the polymer film is 70 to 95%, preferably 75 to 95%, more preferably 80 to 95%, further more preferably 84 to 90%; and / or 10. The polymer film according to claim 9, wherein, The haze of the polymer film is 0.05 to 20%, preferably 0.1 to 16%, more preferably 0.2 to 8%. The method comprises: contacting the polybenzimidazole of any one of claims 1 to 4 and 8 with a second solvent to obtain a solution A; 11. A method of preparing a polymer film, characterized by, preparing a liquid film from the solution A with or without solid-liquid separation; and drying the liquid film to obtain a polymer film. The second solvent includes at least one of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, methanesulfonic acid, formic acid, phosphoric acid, polyphosphoric acid, sulfuric acid and trichlorobenzene; and / or The content of the polybenzimidazole is 0.1 to 20% by weight based on the total weight of the solution A; and / or 12. The method of claim 11, wherein, The conditions of the contacting include that the temperature of the contacting is 30 to 160°C and the time of the contacting is 10 minutes to 24 hours; preferably, the contacting is carried out with stirring, preferably the linear velocity of the stirring is 0.05 to 1 m / s, more preferably 0.1 to 0.8 m / s; and / or The conditions of the drying include that the temperature of the drying is 60 to 160°C and the time of the drying is 0.5 to 24 hours.

13. A polymer film prepared by the method of claim 11 or 12.

14. Use of the polybenzimidazole of any one of claims 1 to 4 and 8 and / or the polymer film of any one of claims 9, 10 and 13 as a light-transmitting or transparent material. ​ ​ 15. Use according to claim 14, wherein, The light-transmitting or transparent material is selected from the group consisting of flexible backsheet for solar cells, flexible display substrate, anti-counterfeiting packaging, high-temperature resistant transparent component for electronic devices / sensors, high-temperature resistant optical lens, high-temperature protective mask, flexible printed circuit, and aircraft cockpit protective cover.

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