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Method for preparing polyimide fibers

A technology of polyimide fiber and polyamic acid, which is applied in the direction of fiber chemical characteristics, single-component synthetic polymer rayon, textiles and papermaking, can solve the problems of poor movement ability of rigid macromolecules and unfavorable fiber properties, etc. Achieve the effects of improving mechanical properties, less environmental pollution, and increasing crystallinity

Inactive Publication Date: 2015-09-23
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Generally speaking, adding rigid monomers into the polymer backbone can effectively improve the mechanical properties of fibers, but rigid macromolecules have poor mobility, which is not conducive to the reduction of defect structures such as holes and the further improvement of fiber performance. The optimized preparation process can effectively improve the size of the pore structure inside the fiber

Method used

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  • Method for preparing polyimide fibers
  • Method for preparing polyimide fibers
  • Method for preparing polyimide fibers

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Synthesis of polyamic acid solution: according to the molar ratio of BPDA: ODPA: p-PDA = 7:3:10, put the diamine p-PDA into a three-necked flask, and add a measured amount of solvent N,N-dimethyl Acetamide (DMAc) was stirred under nitrogen to fully dissolve it, then BPDA and ODPA were mixed evenly and then added in batches and stirred so that the solid content of the solution was 15%. Stirring for 3 hours under the condition of nitrogen protection, the polyamic acid spinning solution with a certain viscosity was obtained, and its intrinsic viscosity was 2.86dL / g.

[0048] Synthesis of partially imidized polyamic acid solution: According to the ratio of 0.6:1 molar ratio of acetic anhydride and diamine, mix acetic anhydride and pyridine (molar ratio is 2:1) and add to the above polyamic acid In the solution, react for 3 hours to obtain a partially imidized polyamic acid solution with an intrinsic viscosity of 2.03 dL / g.

[0049] Preparation of polyamic acid fiber: filte...

Embodiment 2

[0055]Synthesis of polyamic acid solution: according to the molar ratio of BPDA:p-PDA=1:1, put the diamine p-PDA into a three-necked flask, and add a measured amount of solvent N,N-dimethylformamide (DMF ), stirred under nitrogen conditions to fully dissolve, then added BPDA in batches and stirred so that the solid content of the solution was 10%. Stirring for 5 hours under the condition of nitrogen protection, the polyamic acid spinning solution with certain viscosity was obtained, and its intrinsic viscosity was 2.56dL / g.

[0056] Synthesis of partially imidized polyamic acid solution: According to the molar ratio of acetic anhydride and diamine is 0.4:1, mix acetic anhydride and triethylamine (molar ratio is 1:1) and add to the above polyamic acid In the amic acid solution, react for 4 hours to obtain a partially imidized polyamic acid solution with an intrinsic viscosity of 1.95 dL / g.

[0057] Preparation of polyamic acid fiber: filter and defoam the polyamic acid solutio...

Embodiment 3

[0061] Synthesis of polyamic acid solution: according to the molar ratio of BPDA:p-PDA:ODA=10:5:5, put the diamine p-PDA and ODA into a three-necked flask, and add a measured amount of solvent dimethyl sulfoxide (DMSO), stirred under the condition of nitrogen to make it fully dissolved, then added BPDA in batches and stirred, so that the solid content of the solution was 20%. The mixture was stirred for 4 hours under the protection of nitrogen to obtain a polyamic acid spinning solution with a certain viscosity, and its intrinsic viscosity was 2.77dL / g.

[0062] Synthesis of partially imidized polyamic acid solution: According to the ratio of 0.8:1 molar ratio of acetic anhydride and diamine, mix acetic anhydride and pyridine (molar ratio is 4:1) and add to the above polyamic acid In the solution, react for 2.5 hours to obtain a partially imidized polyamic acid solution with an intrinsic viscosity of 2.15 dL / g.

[0063] Preparation of polyamic acid fiber: filter and defoam th...

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Abstract

A method for preparing polyimide fibers belongs to the field of high-performance organic fibers. The method comprises the following steps: preparing a copolymerized polyamide acid spinning solution through condensation polymerization of dianhydride and diamine; adding acetic anhydride and a catalyst in the polyamide acid spinning solution to obtain partly imidized polyamide acid spinning solution; spinning by adopting a wet or dry-wet spinning process, and solidifying and washing to obtain partly imidized polyimide fibers; conducting thermal imidization on the fibers at gradient temperature, and preparing the polyimide fibers with high strength, high modulus and high mechanical performance. The method provided by the invention is used for preparing the polyimide fibers by combination of chemical imidization and thermal imidization, and can be used for further improving the mechanical performance of the polyimide fibers, thereby meeting requirements of various applications.

Description

technical field [0001] The invention belongs to the technical field of high-performance organic fibers, and in particular relates to a preparation method of polyimide fibers. Background technique [0002] Due to the unique rigid structure of the molecular chain, polyimide fibers have excellent mechanical properties, good chemical stability, heat resistance and radiation resistance, etc., so they are widely used in aerospace, national defense, flame retardant protection and Atomic devices and other fields. At present, a two-step method is commonly used to prepare polyimide fibers, that is, the polyamic acid prepolymer is prepared by the reaction of dianhydride and diamine, and then the polyimide fiber is obtained by thermal imidization or chemical imidization dehydration. . However, during the preparation of polyimide fibers by the two-step method, the double diffusion effect and the removal of small molecules during thermal imidization will lead to the generation of hole s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F6/78D01F6/74
Inventor 武德珍常晶菁牛鸿庆张梦颖葛启彦刘威威曹丽孙萌
Owner BEIJING UNIV OF CHEM TECH
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