Polyimide fibre containing benzimidazole structure and preparation method thereof

Abstract

The invention discloses polyimide fiber with benzimidazole structure, which is characterized in that the infrared spectrum of the fiber is provided with character absorption peaks of imide ring of 1776-1774cm<-1>, 1726-1722cm<-1> and 1378-1373cm<-1> within the wave number range of 1300-1800cm<-1> and N-H functional group absorption wide peaks in the imidazole structure within the wave number range of 3000-3750cm<-1>. The tensile strength is 0.73-1.53GPa. The initial modulus is 45.2-220GPa. The invention also provides a preparation method of the fiber. The fiber disclosed by the invention contains the benzimidazole structure with secondary amine hydrogen. Therefore, compared with PMDA-ODA polyimide fiber prepared with the same process, the tensile strength can be improved by nearly three times at the most, the initial modulus can be improved by more than twenty times at the most, and the heat resistance is further improved. The preparation method provided by the invention has the advantages of mature technology and easy control. The cost can be kept at a relative low level.

Description

technical field

[0001] The invention belongs to the technical field of polyimide fibers and preparation methods thereof, and in particular relates to a polyimide fiber containing a benzimidazole structure and a preparation method thereof. Background technique

[0002] Compared with other high-performance fibers, polyimide fiber (PI) is expected to be used in the atomic energy industry, space and It has been widely used in very harsh research in the fields of environment, rescue needs, aerospace, national defense construction, new construction, high-speed transportation, marine development, sports equipment, new energy, environmental industry and protective equipment.

[0003] The preparation method of existing polyimide fiber generally comprises one-step method and two-step method technology, and its technological process is as follows figure 1 shown. One-step method is to use polyimide solution to directly spin to prepare polyimide fiber. Such as Chinese invention patent...

Examples

Embodiment 1

[0032] The synthesis of polyamic acid solution is by PMDA: ODA: PABZ=10: 9: 1 molar ratio, first ODA and PABZ two kinds of diamine monomers are added in the solvent N-methylpyrrolidone of metering, make its total solid content be 12%, then stirred under the protection of nitrogen to dissolve all ODA and PABZ, then added PMDA and stirred, and continued to react at 15°C for 10 hours in a nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 3.16dL / g.

[0033]Polyamic acid fiber spinning The obtained polyamic acid solution is filtered, defoamed, and conventional dry / wet spinning technology is used to obtain polyamic acid fiber, wherein the number of spinneret holes used is 30 to 100 holes, and the hole diameter is 0.1 mm; the coagulation bath used is a mixture of ethanol and water, the weight ratio of which is 50:50, and the stretching ratio of the fiber in the spinning stage is 1.5. In addition, the spinning process can also adop...

Embodiment 2

[0038] The synthesis of the polyamic acid solution is based on the molar ratio of PMDA: ODA: PABZ=10: 7: 3, and first, two diamine monomers, ODA and PABZ, are added to the measured solvent N-methylpyrrolidone, so that the total solid content is 12%, then stirred under nitrogen protection to dissolve ODA and PABZ completely, and then added PMDA and stirred to continue the reaction at 30° C. for 15 hours in nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 2.73dL / g.

[0039] Since the process of polyamic acid fiber spinning and polyamic acid fiber imidization is exactly the same as that in Example 1, it is omitted.

[0040] The structural formula of the obtained polyimide fiber is shown in Example 1, where n:m=7:3, its tensile strength is 0.92GPa, its initial modulus is 56.6GPa, and its elongation at break is 6.6%; The glass transition temperature was 410°C.

Embodiment 3

[0042] The synthesis of the polyamic acid solution is based on the molar ratio of PMDA: ODA: PABZ=10: 5: 5. First, two diamine monomers, ODA and PABZ, are added to the measured solvent N-methylpyrrolidone, so that the solid content is 10 %, and then stirred under nitrogen protection to dissolve ODA and PABZ completely, and then added PMDA and stirred to continue the reaction at 40° C. for 24 hours in a nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 2.35dL / g.

[0043] Since the process of polyamic acid fiber spinning and polyamic acid fiber imidization is exactly the same as that in Example 1, it is omitted.

[0044] The structural formula of the obtained polyimide fiber is shown in Example 1, where n:m=5:5, its tensile strength is 1.26GPa, its initial modulus is 130.7GPa, and its elongation at break is 5.8%; The glass transition temperature was 425°C.

technical field

[0001] The invention belongs to the technical field of polyimide fibers and preparation methods thereof, and in particular relates to a polyimide fiber containing a benzimidazole structure and a preparation method thereof. Background technique

[0002] Compared with other high-performance fibers, polyimide fiber (PI) is expected to be used in the atomic energy industry, space and It has been widely used in very harsh research in the fields of environment, rescue needs, aerospace, national defense construction, new construction, high-speed transportation, marine development, sports equipment, new energy, environmental industry and protective equipment.

[0003] The preparation method of existing polyimide fiber generally comprises one-step method and two-step method technology, and its technological process is as follows figure 1 shown. One-step method is to use polyimide solution to directly spin to prepare polyimide fiber. Such as Chinese invention patent...

Examples

Embodiment 1

[0032] The synthesis of polyamic acid solution is by PMDA: ODA: PABZ=10: 9: 1 molar ratio, first ODA and PABZ two kinds of diamine monomers are added in the solvent N-methylpyrrolidone of metering, make its total solid content be 12%, then stirred under the protection of nitrogen to dissolve all ODA and PABZ, then added PMDA and stirred, and continued to react at 15°C for 10 hours in a nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 3.16dL / g.

[0033]Polyamic acid fiber spinning The obtained polyamic acid solution is filtered, defoamed, and conventional dry / wet spinning technology is used to obtain polyamic acid fiber, wherein the number of spinneret holes used is 30 to 100 holes, and the hole diameter is 0.1 mm; the coagulation bath used is a mixture of ethanol and water, the weight ratio of which is 50:50, and the stretching ratio of the fiber in the spinning stage is 1.5. In addition, the spinning process can also adop...

Embodiment 2

[0038] The synthesis of the polyamic acid solution is based on the molar ratio of PMDA: ODA: PABZ=10: 7: 3, and first, two diamine monomers, ODA and PABZ, are added to the measured solvent N-methylpyrrolidone, so that the total solid content is 12%, then stirred under nitrogen protection to dissolve ODA and PABZ completely, and then added PMDA and stirred to continue the reaction at 30° C. for 15 hours in nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 2.73dL / g.

[0039] Since the process of polyamic acid fiber spinning and polyamic acid fiber imidization is exactly the same as that in Example 1, it is omitted.

[0040] The structural formula of the obtained polyimide fiber is shown in Example 1, where n:m=7:3, its tensile strength is 0.92GPa, its initial modulus is 56.6GPa, and its elongation at break is 6.6%; The glass transition temperature was 410°C.

Embodiment 3

[0042] The synthesis of the polyamic acid solution is based on the molar ratio of PMDA: ODA: PABZ=10: 5: 5. First, two diamine monomers, ODA and PABZ, are added to the measured solvent N-methylpyrrolidone, so that the solid content is 10 %, and then stirred under nitrogen protection to dissolve ODA and PABZ completely, and then added PMDA and stirred to continue the reaction at 40° C. for 24 hours in a nitrogen atmosphere to obtain a viscous polyamic acid homogeneous solution. Its intrinsic viscosity is 2.35dL / g.

[0043] Since the process of polyamic acid fiber spinning and polyamic acid fiber imidization is exactly the same as that in Example 1, it is omitted.

[0044] The structural formula of the obtained polyimide fiber is shown in Example 1, where n:m=5:5, its tensile strength is 1.26GPa, its initial modulus is 130.7GPa, and its elongation at break is 5.8%; The glass transition temperature was 425°C.

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