Azo-containing polymer as well as preparation method and application thereof

Abstract

The invention provides an azo-containing polymer as well as a preparation method and application thereof. The azo-containing polymer is prepared from the following raw materials: aryl azo primary amine, bifunctional epoxy resin, a monofunctional epoxy compound and an organic solvent. The azo-containing polymer provided by the invention has obvious ultraviolet sensitivity and wide ultraviolet absorptivity, can effectively generate photochemical decomposition under ultraviolet laser with low laser energy density, generates small molecular fragments, realizes clean ablation, does not pollute a system, is convenient for cleaning and recycling of a matrix, and has a wide application prospect. Good strong acid and strong alkali resistance is achieved; meanwhile, the synthetic process of the azo-containing polymer is safe, the stability is very good, and the azo-containing polymer has a long-acting shelf life.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and relates to an azo-containing polymer and a preparation method and application thereof, and specifically relates to an azo-containing polymer capable of realizing low-energy ultraviolet cleaning ablation and a preparation method and application thereof. Background Art

[0002] At present, laser ablation of polymers has received widespread attention and has been reported in a large number of literatures. These studies cover multiple aspects such as photodecomposition, surface modification, film formation and material transfer during laser ablation, and have developed a variety of photosensitive polymer materials suitable for laser ablation. These specially designed photosensitive polymers will undergo significant changes in structure or performance under the action of lasers to achieve specific functional requirements. According to the light source, this type of research can be divided into infrared laser ablation and ultraviolet laser ablation. Compared with infrared laser ablation technology, ultraviolet laser ablation can avoid the side effects caused by high heat load and high temperature in the ablation process. However, ultraviolet lasers have high energy, and when irradiated to single molecules, living cells or semiconductor polymers containing photosensitive substances, violent photochemical reactions will occur, thereby destroying such systems. These factors limit the practical application of photosensitive polymers and production processes that can be ablated by ultraviolet lasers.

[0003] In addition, many studies have reported the synthesis of a series of laser ablation polymers with arylazo groups as the core, including polyalkylarylazosulfur compounds, diazosulfonate polymers, copolyesters containing triazene groups, polyurethanes containing triazene groups, and polyacrylates containing triazene groups. Among the many polymers for laser ablation, polymers containing triazene structures show excellent ultraviolet light decomposition and ablation capabilities. They can be effectively decomposed under the action of ultraviolet lasers and show good ultraviolet laser ablation performance. However, the triazene structure is extremely unstable and there are dangers of explosion during synthesis, storage, transfer and application. Therefore, in order to avoid the high temperature load caused by infrared lasers and the high energy problems caused by ultraviolet lasers, and to meet the practical application requirements of biological cell transmission, high-precision full-color printing, release of micro-electromechanical system components, and transfer of semiconductor polymer structures in organic light-emitting diodes, it is particularly important to develop a new type of photosensitive polymer that can achieve low-energy ultraviolet laser ablation while having good thermal stability. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an azo-containing polymer and a preparation method and application thereof, and specifically to provide an azo-containing polymer capable of achieving low-energy ultraviolet cleaning ablation and a preparation method and application thereof. The present invention solves the problem of poor stability of existing photosensitive polymers capable of ultraviolet laser ablation, and provides a new azo-containing photosensitive polymer that can be safely synthesized, can achieve low-energy ultraviolet cleaning ablation and has good thermal stability.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an azo-containing polymer, wherein raw materials for preparing the azo-containing polymer include an aromatic azo primary amine, a difunctional epoxy resin, a monofunctional epoxy compound and an organic solvent.

[0007] The azo-containing polymer provided by the present invention has obvious ultraviolet sensitivity and wide ultraviolet absorption, and can effectively produce photochemical decomposition under ultraviolet laser with low laser energy density to generate small molecular fragments, realize clean ablation, do not pollute the system, and facilitate the cleaning and recycling of the matrix; at the same time, the synthesis process of the azo-containing polymer is safe, the stability is very good, and it has a long shelf life.

[0008] Preferably, the aromatic azo primary amine includes any one of 4,4'-diaminoazobenzene, 4-amino-4'-dimethylaminoazobenzene, 4-amino-4'-methylaminoazobenzene, 2,3-difluoro-4-aminoazobenzene, ethyl 4-((4-aminophenyl)azo)benzoate, 4-aminoazobenzene, 4-amino-4',4'-diethylaminoazobenzene, and 4-amino-4'-hydroxyaminoazobenzene, or a combination of at least two thereof.

[0009] Preferably, the difunctional epoxy resin comprises an aromatic epoxy resin and / or an aliphatic epoxy resin.

[0010] Preferably, the aromatic epoxy resin comprises any one or a combination of at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, tetrabromobisphenol A epoxy resin, resorcinol epoxy resin, resorcinol formaldehyde epoxy resin, o-cresol epoxy resin, p-cresol epoxy resin, p-tert-butylphenol epoxy resin, hydroquinone epoxy resin, trimethylolphenol epoxy resin, bis(4-aminophenoxy)phenyl epoxy resin, bis(3-aminophenoxy)phenyl epoxy resin, bis(2-aminoethyl)phenyl epoxy resin, bis(3-glycidyloxyphenoxy)phenyl epoxy resin, bis(4-glycidyloxyphenoxy)phenyl epoxy resin, bis(2-glycidyloxyethoxy)phenyl epoxy resin, bis(3-glycidyloxypropoxy)phenyl epoxy resin, and bis(4-glycidyloxybutoxy)phenyl epoxy resin.

[0011] Preferably, the aliphatic epoxy resin includes any one of HK-66 (alkylene glycidyl ether), 501 (butyl glycidyl ether), 622 (1,4-butanediol diglycidyl ether), 669 (ethylene glycol diglycidyl ether), X-632 (polypropylene glycol diglycidyl ether), AGE (C12-14 fatty glycidyl ether), and X-652 (1,6-hexanediol diglycidyl ether) or a combination of at least two thereof.

[0012] Preferably, the monofunctional epoxy compound includes any one or a combination of at least two of 3-glycidyloxypropyltrimethoxysilane, 2,3-epoxypropylphenyl ether, 1-allyloxy-2,3-epoxypropylene, 2(3-methylphenoxymethyl)ethylene oxide, and glycidyl isobutyl ether.

[0013] Preferably, the organic solvent includes, but is not limited to, any one of ketone solvents, aromatic hydrocarbon solvents, ether solvents, ester solvents, amide solvents, dimethyl sulfoxide, and decalin, or a combination of at least two thereof.

[0014] Preferably, the ketone solvent includes any one of acetone, butanone, cyclohexanone and isophorone, or a combination of at least two thereof.

[0015] Preferably, the aromatic hydrocarbon solvent includes toluene and / or trimethylbenzene.

[0016] Preferably, the ether solvent includes any one of dioxane, 1,3-dioxolane, 2,2,4,4,5,5-hexamethyl-1,3-dioxolane, 2,2-dimethoxy-4-(trifluoromethyl)-1,3-dioxolane ether, tetrahydrofuran, and a fluorinated hexacyclic coordination ether, or a combination of at least two thereof.

[0017] Preferably, the ester solvent includes ethylene glycol methyl ether acetate and / or propylene glycol methyl ether acetate.

[0018] Preferably, the amide solvent includes dimethylformamide and / or N,N-dimethylacetamide.

[0019] Preferably, the molar ratio of the epoxy group in the difunctional epoxy resin to the primary amine group in the aromatic azo primary amine is 1:(0.3-0.9), such as 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, etc., and specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, preferably 1:(0.4-0.75). If the proportion of the aromatic azo primary amine is too small, the difunctional epoxy resin monomer is easy to remain, which will affect the chemical resistance of the polymer; if the proportion of the aromatic azo primary amine is too large, the molecular weight of the polymer will be low and the thermal stability will be poor.

[0020] Preferably, the molar ratio of the monofunctional epoxy compound to the primary amine group in the aromatic azo primary amine is 1:(2.5-15), for example, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5, 1:15, etc., as well as specific ratios between the above ratios. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific ratios included in the ratio range, preferably 1:(5-12). Monofunctional epoxy compounds play a capping role. If their usage ratio is too small, they cannot completely protect the end groups of macromolecules. If their usage ratio is too large, small molecules will remain in the reaction system and increase costs.

[0021] Preferably, based on the total weight of the raw materials for preparing the azo polymer as 100%, the amount of the organic solvent is 30% to 70%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc., and specific values ​​between the above values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific values ​​included in the range, preferably 40% to 60%. If the amount of organic solvent is too much, it is difficult to increase the molecular weight of the polymer; if the amount of organic solvent is too little, the reactants are easy to precipitate, resulting in uneven reaction.

[0022] Preferably, the number average molecular weight of the azo-containing polymer is below 100,000, for example, 100,000, 90,000, 80,000, 70,000, 60,000, 50,000, 30,000, 10,000, 9,000, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, preferably 9,000 to 50,000.

[0023] Preferably, the maximum thermal weight loss rate temperature of the azo-containing polymer is above 265°C, for example 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0024] Preferably, the glass transition temperature of the azo-containing polymer is above 60°C, for example 60°C, 70°C, 80°C, 90°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0025] In a second aspect, the present invention provides a method for preparing the azo-containing polymer as described in the first aspect, the preparation method comprising the following steps:

[0026] (1) mixing an aromatic azo primary amine and a portion of an organic solvent and heating the mixture;

[0027] (2) Mixing a difunctional epoxy resin and the remaining organic solvent, adding the obtained mixed solution to step (1), reacting, then adding a monofunctional epoxy compound, continuing the reaction to obtain an organic solution containing an azo polymer, and removing the organic solvent to obtain the azo polymer.

[0028] The azo-containing polymer of the present invention is prepared by using aromatic azo primary amine and difunctional epoxy resin as monomers, and adding monofunctional epoxy compound during the polymerization process to cause ring-opening polymerization.

[0029] Preferably, the temperature in step (1) is increased to 120-180°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0030] Preferably, the step (2) of adding the obtained mixed solution to the step (1) specifically comprises: adding the obtained mixed solution dropwise to the step (1), and controlling the addition to be completed within 8 to 15 minutes (for example, 8 minutes, 10 minutes, 12 minutes, 13 minutes, 15 minutes, etc., as well as specific point values ​​between the above point values; due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the said range).

[0031] Preferably, the reaction time of step (2) is 15 to 48 h, for example, 15 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h, 36 h, 38 h, 40 h, 42 h, 44 h, 48 h, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the said range.

[0032] Preferably, the time for continuing the reaction in step (2) is 2 to 4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0033] It should be noted that the present invention does not impose any specific limitation on the amount of the organic solvent used in step (1), as long as it can dissolve the aromatic azo primary amine and the remaining organic solvent can dissolve the difunctional epoxy resin.

[0034] In a third aspect, the present invention provides an azo polymer-containing film, wherein the azo polymer-containing film is prepared from the azo polymer described in the first aspect.

[0035] In a fourth aspect, the present invention provides an application of the azo-containing polymer as described in the first aspect or the azo-containing polymer film as described in the third aspect in photoresist, mass transfer, and biomedicine.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] The azo-containing polymer provided by the present invention has obvious ultraviolet sensitivity and wide ultraviolet absorption, and can effectively produce photochemical decomposition under ultraviolet laser with low laser energy density to generate small molecular fragments, realize clean ablation, do not pollute the system, and is convenient for cleaning and recycling of the matrix, and has good resistance to strong acids and alkalis; at the same time, the synthesis process of the azo-containing polymer is safe, the stability is very good, and it has a long shelf life. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0039] Example 1

[0040] In this embodiment, an azo-containing polymer is provided, and the preparation method comprises the following steps:

[0041] (1) Add 10.0 g of 4-aminoazobenzene into a 250 mL three-necked flask, add 10.0 g of propylene glycol methyl ether acetate, stir to dissolve, and heat the solution to 180° C.;

[0042] (2) 14.3 g of bisphenol A epoxy resin (epoxy equivalent weight: 178) was dissolved in 14.3 g of propylene glycol methyl ether acetate, and then slowly added dropwise to a three-necked flask for 10 min. After the addition was completed, the reaction was continued for 16 h, and then 1.0 g of 3-glycidyloxypropyltrimethoxysilane was added. The reaction was continued for 2 h, and the heating was stopped and the room temperature was restored to obtain an organic solution containing an azo polymer. The organic solvent was removed to obtain the azo polymer.

[0043] Example 2

[0044] In this embodiment, an azo-containing polymer is provided, and the preparation method comprises the following steps:

[0045] (1) Add 12.0 g of 4-aminoazobenzene into a 250 mL three-necked flask, add 15.0 g of ethylene glycol methyl ether acetate, stir to dissolve, and heat the solution to 140° C.;

[0046] (2) 16.5 g of bisphenol F epoxy resin (epoxy equivalent of 190) was dissolved in 20.0 g of ethylene glycol methyl ether acetate, and then slowly added dropwise to a three-necked flask for 13 min. After the addition was completed, the reaction was continued for 48 h. Then, 1.5 g of 3-glycidyloxypropyltrimethoxysilane was added and the reaction was continued for 4 h. The heating was stopped and the room temperature was restored to obtain an organic solution containing an azo polymer. The organic solvent was removed to obtain the azo polymer.

[0047] Example 3

[0048] In this embodiment, an azo-containing polymer is provided, and the preparation method comprises the following steps:

[0049] (1) Add 10.0 g of 4-amino-4',4'-diethylaminoazobenzene to a 250 mL three-necked flask, add 10.0 g of cyclohexanone, start stirring to dissolve, and heat the solution to 150° C.

[0050] (2) 13.2 g of hydroquinone epoxy resin (epoxy equivalent of 150) was dissolved in 13.2 g of cyclohexanone, and then slowly added dropwise to a three-necked flask for 11 min. After the addition was completed, the reaction was continued for 36 h, and then 1.1 g of 2,3-epoxypropylphenyl ether was added and the reaction was continued for 4 h. The heating was stopped and the room temperature was restored to obtain an organic solution containing an azo polymer. The organic solvent was removed to obtain the azo polymer.

[0051] Comparative Example 1

[0052] In this comparative example, an azo-containing polymer is provided, and the preparation method comprises the following steps:

[0053] (1) Add 10.0 g of 4-aminoazobenzene into a 250 mL three-necked flask, add 10.0 g of propylene glycol methyl ether acetate, stir to dissolve, and heat the solution to 180° C.;

[0054] (2) 14.3 g of bisphenol A epoxy resin (epoxy equivalent weight: 178) was dissolved in 14.3 g of propylene glycol methyl ether acetate, and then slowly added dropwise to a three-necked flask for 10 min. After the addition was completed, the reaction was continued for 16 h. The heating was stopped and the room temperature was restored to obtain an organic solution containing an azo polymer. The organic solvent was removed to obtain the azo polymer.

[0055] The azo-containing polymers provided in the examples and comparative examples were tested for performance, and the testing method was as follows:

[0056] (1) Number average molecular weight:

[0057] The test was carried out in accordance with GB / T 27843-2011.

[0058] (2) Maximum thermal weight loss rate temperature:

[0059] Weigh 3-6 mg of azo polymer and use TGA test. The test procedure is: keep the temperature at 40°C for 180s, then increase the temperature to 900°C at a heating rate of 10°C / min to obtain a thermal weight loss curve. The temperature corresponding to the peak value of the absolute value of the first derivative of the curve is taken as the maximum thermal weight loss rate temperature.

[0060] (3) Ultraviolet absorption

[0061] The organic solution containing the azo polymer is coated on a glass substrate and dried. The sample is tested for absorption at different wavelengths using an ultraviolet-visible absorption spectrum. If the absorption value is greater than 0, it has absorption at the wavelength.

[0062] (4) Laser energy density required to achieve clean ablation

[0063] Under a 355 nm laser, lasers with different energy densities were used to irradiate the adhesive film coated on the glass substrate, and the lowest energy at which the adhesive film was completely separated from the substrate was taken as the laser energy density required for cleaning and ablating the azo polymer.

[0064] (5) Strong acid and alkali resistance

[0065] The above-mentioned organic solution containing azo polymer is coated on a glass substrate, dried, and 100 1mm*1mm grids are drawn, and then immersed in a 40% KOH (or 8% HCl) aqueous solution. If the film surface does not fall off after being immersed in the KOH aqueous solution or the HCl aqueous solution, the tolerance is good, otherwise the tolerance is poor.

[0066] The performance test results are shown in Table 1:

[0067] Table 1

[0068] Example 1 Example 2 Example 3 Comparative Example 1 Number average molecular weight 11000 9500 10000 10000 Maximum thermal weight loss rate temperature (℃) 300 284 265 305 Glass transition temperature(℃) 89 78 80 87 Film thickness(nm) 300 450 330 290 UV absorption range 230-510nm 260-450nm 240-490nm 230-500nm <![CDATA[Laser energy density (mJ / cm 2 )]]> 85 75 75 85 Strong acid and alkali resistance Tolerance Tolerance Tolerance Intolerance

[0069] It can be seen from Table 1 that the azo-containing polymers provided in the embodiments of the present invention have a wide range of ultraviolet absorption, and at low laser energy density (75-85 mJ / cm 2 ) ultraviolet laser, photochemical decomposition can be effectively produced to achieve clean ablation, and it has good resistance to strong acids and alkalis; at the same time, the synthesis process of the azo polymer is safe.

[0070] Compared with Example 1, the ultraviolet absorption range of the azo-containing polymer provided in Comparative Example 1 is slightly narrowed, and it is not resistant to strong acids and bases.

[0071] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the azo-containing polymers and the preparation method and application thereof, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An azo-containing polymer, characterized in that The raw materials for preparing the azo-containing polymer include aromatic azo primary amine, difunctional epoxy resin, monofunctional epoxy compound and organic solvent.

2. The azo-containing polymer according to claim 1, characterized in that The aromatic azo primary amine includes any one of 4,4'-diaminoazobenzene, 4-amino-4'-dimethylaminoazobenzene, 4-amino-4'-methylaminoazobenzene, 2,3-difluoro-4-aminoazobenzene, ethyl 4-((4-aminophenyl)azo)benzoate, 4-aminoazobenzene, 4-amino-4',4'-diethylaminoazobenzene, and 4-amino-4'-hydroxyaminoazobenzene, or a combination of at least two thereof.

3. The azo-containing polymer according to claim 1 or 2, characterized in that The difunctional epoxy resin includes an aromatic epoxy resin and / or an aliphatic epoxy resin; Preferably, the aromatic epoxy resin comprises any one of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, hydrogenated bisphenol A epoxy resin, tetrabromobisphenol A epoxy resin, resorcinol epoxy resin, resorcinol formaldehyde epoxy resin, o-cresol epoxy resin, p-cresol epoxy resin, p-tert-butylphenol epoxy resin, hydroquinone epoxy resin, trimethylolphenol epoxy resin, bis(4-aminophenoxy)phenyl epoxy resin, bis(3-aminophenoxy)phenyl epoxy resin, bis(2-aminoethyl)phenyl epoxy resin, bis(3-glycidyloxyphenoxy)phenyl epoxy resin, bis(4-glycidyloxyphenoxy)phenyl epoxy resin, bis(2-glycidyloxyethoxy)phenyl epoxy resin, bis(3-glycidyloxypropoxy)phenyl epoxy resin, and bis(4-glycidyloxybutoxy)phenyl epoxy resin, or a combination of at least two thereof; Preferably, the aliphatic epoxy resin includes any one of HK-66, 501, 622, 669, X-632, AGE, and X-652, or a combination of at least two thereof; Preferably, the monofunctional epoxy compound includes any one or a combination of at least two of 3-glycidyloxypropyltrimethoxysilane, 2,3-epoxypropylphenyl ether, 1-allyloxy-2,3-epoxypropylene, 2(3-methylphenoxymethyl)ethylene oxide, and glycidyl isobutyl ether.

4. The azo-containing polymer according to any one of claims 1 to 3, characterized in that The organic solvent includes but is not limited to any one of ketone solvents, aromatic hydrocarbon solvents, ether solvents, ester solvents, amide solvents, dimethyl sulfoxide, and decalin, or a combination of at least two thereof; Preferably, the ketone solvent includes any one of acetone, butanone, cyclohexanone, and isophorone, or a combination of at least two thereof; Preferably, the aromatic hydrocarbon solvent includes toluene and / or trimethylbenzene; Preferably, the ether solvent includes any one of dioxane, 1,3-dioxolane, 2,2,4,4,5,5-hexamethyl-1,3-dioxolane, 2,2-dimethoxy-4-(trifluoromethyl)-1,3-dioxolane ether, tetrahydrofuran, and a fluorinated hexacyclic coordination ether, or a combination of at least two thereof; Preferably, the ester solvent comprises ethylene glycol methyl ether acetate and / or propylene glycol methyl ether acetate; Preferably, the amide solvent includes dimethylformamide and / or N,N-dimethylacetamide.

5. The azo-containing polymer according to any one of claims 1 to 4, characterized in that The molar ratio of the epoxy group in the difunctional epoxy resin to the primary amine group in the aromatic azo primary amine is 1:(0.3-0.9), preferably 1:(0.4-0.75); Preferably, the molar ratio of the monofunctional epoxy compound to the primary amine group in the aromatic azo primary amine is 1:(2.5-15), preferably 1:(5-12); Preferably, based on the total weight of the raw materials for preparing the azo polymer being 100%, the amount of the organic solvent used is 30% to 70%.

6. The azo-containing polymer according to any one of claims 1 to 5, characterized in that The number average molecular weight of the azo-containing polymer is less than 100,000, preferably 9,000 to 50,000; Preferably, the maximum thermal weight loss rate temperature of the azo-containing polymer is above 265°C; Preferably, the glass transition temperature of the azo-containing polymer is above 60°C.

7. A method for preparing an azo-containing polymer as claimed in any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) mixing an aromatic azo primary amine and a portion of an organic solvent and heating the mixture; (2) Mixing a difunctional epoxy resin and the remaining organic solvent, adding the obtained mixed solution to step (1), reacting, then adding a monofunctional epoxy compound, continuing the reaction to obtain an organic solution containing an azo polymer, and removing the organic solvent to obtain the azo polymer.

8. The preparation method according to claim 7, characterized in that: The heating in step (1) is to be raised to 120-180° C.; Preferably, the step (2) of adding the obtained mixed solution to the step (1) specifically comprises: adding the obtained mixed solution dropwise to the step (1), and controlling the addition to be completed within 8 to 15 minutes; Preferably, the reaction time in step (2) is 15 to 48 hours; Preferably, the reaction time in step (2) is 2 to 4 hours.

9. An azo polymer film, characterized in that: The azo-containing polymer film is prepared from the azo-containing polymer according to any one of claims 1 to 6.

10. Use of the azo-containing polymer according to any one of claims 1 to 6 or the azo-containing polymer film according to claim 9 in photoresist, mass transfer, and biomedicine.