Method for preparing super-high molecular weight polyacrylonitrile-base carbon fiber spinning primary fluid

A polyacrylonitrile-based carbon fiber and ultra-high molecular weight technology, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems of restricting the performance of PAN fibers, low molecular weight of PAN, slow polymerization speed, etc., and achieve favorable stirring and heat transfer , Save the demulsification process and save production costs

Inactive Publication Date: 2008-09-10
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, domestic related patents on PAN spinning for carbon fiber are mostly synthesized by one-step solution polymerization (application number: 200510016572.X, 200510012581.1, 02155488.9). Slower and other problems, the obtained PAN molecular weight is low, and the molecular weight distribution is wide, which restricts the performance of PAN fiber, and it is not easy to obtain high modulus PAN fiber
The Shanxi Institute of Coal Chemistry of the Chinese Academy of Sciences has disclosed three Chinese invention patents (application numbers: 02130021.6, 02130023.2, 02130022.4), which use organic solvents and water as the polymerization medium to solve the problem of uneven polymerization system and slow polymerization speed, but the PAN Molecular weight size and molecular weight distribution did not change significantly
Japan's Mitsubishi rayon company uses DMF and water as the polymerization medium (JK. Ping 9-3722, Zhao 63-35819), wherein DMF / water is 1 / 4, and finally obtains PAN with a weight average molecular weight of 820,000 and a molecular weight distribution of 3.4 , although the molecular weight is larger, the molecular weight distribution is still broad

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] In a 2L four-neck flask, 5g of Span80 was dissolved in 250g of heptane, then 95g of AN, 1g of IA, 4g of MMA, and 250g of distilled water were added and stirred until a uniform emulsion was formed. Nitrogen was passed through for 0.5 hour to drive out the air. Subsequently, 0.5 g of AIBN was dissolved in 10 g of heptane and added dropwise. Afterwards, nitrogen protection was continued, and the reaction was performed at a water bath temperature of 52° C., with a stirring speed of 500 rpm. After half an hour, a precipitate gradually precipitated out. After 8 hours, the reaction was terminated. Filter, repeat washing with water and isopropanol, and dehumidify and dry in a drying oven at 80°C for 16 hours. It was determined that the polymerization conversion rate was 74%, the molecular weight of PAN was 1.17 million, and the molecular weight distribution was 1.46. Then the dried homopolymer is dissolved in a certain amount of DMF, defoamed, and left standing at 50° C. for ...

Embodiment 2

[0029] In a 2L four-necked flask, 5g of Span60 was dissolved in 250g of heptane, then 92g of AN, 2g of IA, 6g of MMA, and 250g of distilled water were added and stirred until a uniform emulsion was formed. Nitrogen was passed through for 0.5 hour to drive out the air. Then 0.5g AIBN was dissolved in 10g heptane and added dropwise. Afterwards, nitrogen protection was continued, and the reaction was performed at a water bath temperature of 52° C., with a stirring speed of 500 rpm. After half an hour, a precipitate gradually precipitated out. After 16 hours, the reaction was terminated. Filter, repeat washing with water and isopropanol, and dehumidify and dry in a drying oven at 80°C for 16 hours. It was determined that the polymerization conversion rate was 83%, the molecular weight of PAN was 1.24 million, and the molecular weight distribution was 1.52. Then the dried homopolymer is dissolved in a certain amount of DMF, defoamed, and left standing at 50° C. for 24 hours to ob...

Embodiment 3

[0031]In a 2L four-necked flask, 5g of Tween80 was dissolved in 250g of heptane, then 98g of AN, 2g of IA, 0g of MMA, and 250g of distilled water were added and stirred until a uniform emulsion was formed. Nitrogen was passed through for 0.5 hour to drive out the air. Then 0.5g AIBN was dissolved in 10g heptane and added dropwise. Afterwards, nitrogen protection was continued, and the reaction was carried out at a water bath temperature of 52° C., with a stirring speed of 500 rpm. After half an hour, a precipitate gradually precipitated out. After 24 hours, the reaction was terminated. Filter, repeat washing with water and isopropanol, and dehumidify and dry in a drying oven at 80°C for 16 hours. It was determined that the polymerization conversion rate was 87%, the molecular weight of PAN was 1.26 million, and the molecular weight distribution was 1.62. Then the dried homopolymer is dissolved in a certain amount of DMF, defoamed, and left standing at 50° C. for 24 hours to ...

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Abstract

The invention relates to a polymerization process of polyacrylonitrile with super high molecular weight, in particular to a method used to prepare high-performance polyacrylonitrile-based carbon fibre spinning dope. The method comprises the following steps: firstly, emulsifying agent is dissolved in heptane; then, acrylonitrile aqueous solution is added and stirred so as to be dispersed and emulsified; when dissolved in a small amount of heptane, initiator is dripped into the emulsified liquid (which is oil-soluble and enters into an external phase); nitrogen is pumped in and the reaction begins at 50 to 65 DEG C and at a stirring speed ranging between 200 and 1,000 r / min; after the reaction is finished, polyacrylonitrile powder can be obtained through deaeration and drying; and finally, spinning dope is obtained after the polyacrylonitrile powder is redissolved and deaerated. The polyacrylonitrile obtained according to the method has high molecular weight (i.e. Mw is more than 1,000,000) and substantially reduced molecular weight distribution (i.e. Mw / Mn is less than 2).

Description

technical field [0001] The invention relates to a polymerization process of ultra-high molecular weight polyacrylonitrile (PAN), in particular to a method for preparing high-performance polyacrylonitrile-based carbon fiber spinning dope. The method of the present invention is a kind of utilization inverse emulsion polymerization, thereby obtains ultrahigh molecular weight (M w >1 million), narrow molecular weight distribution (M w / M n <2) The method of polyacrylonitrile-based carbon fiber spinning dope. Background technique [0002] Carbon fiber has excellent characteristics such as high specific modulus, high specific strength, high temperature resistance, and corrosion resistance, and has been widely used in various fields. Polyacrylonitrile-based carbon fibers are made of polymers with acrylonitrile (AN) as the main chain structure unit after spinning and carbonization. It has two advantages of high mechanical properties and low cost. Compared with PAN fibers f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F220/44C08F4/04C08F2/30D01F9/22
Inventor 刘必前田野张友全王丽华丁怀宇李兰徐坚
Owner INST OF CHEM CHINESE ACAD OF SCI
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