Preparation method of polymer for polyacrylonitrile-based carbon fiber precursor without metal ions in polymerization system

A polyacrylonitrile-based carbon fiber and metal ion technology, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, can solve the problems of narrow product molecular weight distribution, affecting carbon fiber performance, and high polymerization conversion rate, so as to improve polymer purity and production cost. Low, high polymerization conversion effect

Pending Publication Date: 2022-05-06
敖琪
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At the same time, this method usually adopts a water-soluble oxidation-reduction initiation system, which has the advantages of fast polymerization rate, low reaction temperature, narrow molecular weight distribution of the obtained product, and high polymerization conversion rate; Chinese patents CN109721677A, CN104372431A, CN109721678A A two-step method is used to prepare polyacrylonitrile spinning dope for carbon fibers with a redox system initiator; however, since the two-step polymerization process generally uses a redox system, most of them contain alkali metal ion impurities; the raw silk is pre-oxidized and carbonized. When the metal ion impurity exists, it is very easy to catalyze the oxidation of carbon to produce CO, CO 2 Such gas makes the interior of carbon fibers form void defects, and alkali metal impurities will exist in the interior of carbon fibers in the form of oxides, which seriously affects the performance of carbon fibers; therefore, for carbon fibers with excellent performance, the high purification of the original silk is also very important; prior art The removal of metal impurities is basically by means of washing, which can remove the impurities existing on the surface of the protofilament fiber, but it is generally believed that the impurities from the polymerization initiation system exist on the polymer molecular chain and are difficult to remove by washing. High-performance polyacrylonitrile carbon fiber provides high-quality spinning dope

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] 1) Add 960g of acrylonitrile, 20g of methyl acrylate, 20g of itaconic acid and 2000g of deionized water into the reactor at room temperature, stir at 100rpm, raise the temperature to 50°C and keep the temperature at this temperature for 0.5h. The ammonium reducing agent ammonium bisulfite was added, and the reaction was maintained at 50°C for 1.5 hours; the above polymer slurry was filtered, singled out, and dried to obtain a white polyacrylonitrile powder; the weight average molecular weight of polyacrylonitrile was 322,000, and the molecular weight distribution The index is 1.45;

[0016] 2) Mix polyacrylonitrile powder with dimethylacetamide to prepare a spinning solution with a solid content of 20%, then heat the spinning solution and spray it into a coagulation bath, and negatively draw it by 0.2%. The fibers are rinsed with deionized water to remove the solvent, and at the same time oiled at a draft ratio of 9.98. After the oiled fibers are kept at 150°C for 4 to ...

Embodiment 2

[0018] 1) Add 960g acrylonitrile, 20g methyl acrylate, 20g itaconic acid and 2000g deionized water into the reactor at room temperature, stir at 100rpm, raise the temperature to 55°C and keep the temperature at this temperature for 0.5h. The ammonium reducing agent ammonium bisulfite was added, and the reaction was maintained at 57°C for 1 hour; the above-mentioned polymer slurry was filtered, singled out, and dried to obtain a white polyacrylonitrile powder; the weight average molecular weight of polyacrylonitrile was 396,000, and the molecular weight distribution Index is 1.60;

[0019] 2) Mix polyacrylonitrile powder and dimethylacetamide to prepare a spinning solution with a solid content of 20%, then heat the spinning solution and spray it into a coagulation bath, negatively draw 0.2%, and the obtained as-spun fiber Rinse with deionized water to remove the solvent, and at the same time carry out oiling at a draft ratio of 9.98. After the oiled fibers stay at 150°C for 4 t...

Embodiment 3

[0021] 1) Add 960g acrylonitrile, 20g methyl acrylate, 20g itaconic acid and 2000g deionized water into the reactor at room temperature, stir at 100rpm, raise the temperature to 55°C and keep the temperature at this temperature for 0.5h. After the ammonium reducing agent ammonium sulfite was added, the reaction was kept at 55°C for 1.5 hours; the above-mentioned polymer slurry was filtered, singled out, and dried to obtain a white polyacrylonitrile powder; The index is 1.59;

[0022] 2) Mix polyacrylonitrile powder and dimethylacetamide to prepare a spinning solution with a solid content of 20%, then heat the spinning solution and spray it into a coagulation bath, negatively draw 0.2%, and the obtained as-spun fiber Rinse with 0 deionized water to remove the solvent, and at the same time carry out oiling at a draft ratio of 9.98. After oiling, the fiber stays at 150°C for 4 to 5 minutes to dry and compact, and then it is made into a polyacrylonitrile-based carbon fiber. Silk;...

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Abstract

The invention relates to a preparation method of a polymer for a polyacrylonitrile-based carbon fiber precursor without metal ions in a polymerization system, which comprises the following steps: mixing monomer acrylonitrile, a second polymerization monomer, a third polymerization monomer and deionized water, heating and keeping at 45-65 DEG C, stirring at 100 rpm, respectively dropwise adding a water-soluble initiator into a reactor at the same titration rate at the same time, and reacting at the temperature of 45-65 DEG C for 2-3 hours; after dropwise adding the initiator, reacting for 30 to 120 minutes; removing residual monomers, washing and drying to obtain polyacrylonitrile powder; wherein in terms of the mass of all the polymerization monomers, the monomer acrylonitrile accounts for 92-99 wt%, the feeding amount of the second copolymerization monomer accounts for 1-7.0 wt%, the feeding amount of the third copolymerization monomer accounts for 0.1-3.0 wt%, and the use amount of the initiator accounts for 0.1-2.0 wt%; and an initiator. The method has the advantages of fast polymerization reaction speed, low reaction temperature, high polymerization conversion rate and low production cost. As the polymerization system does not contain metal ions, the polyacrylonitrile-based carbon fiber precursor with high purification and high quality can be obtained, and further the carbon fiber with high performance can be obtained.

Description

technical field [0001] The invention relates to a method for preparing a polymer for polyacrylonitrile carbon fiber precursors, in particular to a method for preparing a polymer for polyacrylonitrile-based carbon fiber precursors whose polymerization system does not contain metal ions. Background technique [0002] Carbon fiber is an excellent reinforcing fiber material because of its high strength, high modulus, high temperature resistance, wear resistance, corrosion resistance, fatigue resistance, creep resistance, small linear expansion coefficient, good electrical and thermal conductivity, etc. Advantages, it is widely used in many fields such as aerospace, marine transportation, rail transit vehicles, wind turbine blades, medical and industrial equipment, sports and leisure products; with the continuous expansion of application fields, the strength requirements of carbon fiber continue to increase. [0003] The preparation process of high-performance polyacrylonitrile-b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F220/46C08F220/14C08F222/02C08F4/40D01F9/22
CPCC08F220/46C08F4/40D01F9/22C08F220/14C08F222/02
Inventor 王进军敖琪庄晗
Owner 敖琪
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