Method for preparing pre-oxidized polyacrylonitrile fiber by melt spinning

A technology of pre-oxidizing fiber and polyacrylonitrile, which is applied in the direction of melt spinning, fiber chemical characteristics, textiles and papermaking, etc. It can solve the problems of complex equipment, reduced mechanical properties of carbon fibers, and lower pre-oxidation temperature, so as to reduce production costs, The effect of increasing the degree of pre-oxidation and improving compactness

Inactive Publication Date: 2011-11-23
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Chinese patents 02136722.1 and 200810036189.4 indicate that the production process of layered thermal stabilization furnace with heating and drawing in 6-12 zones can be used. This method can prepare high-quality pre-oxidized fibers. However, the method is extremely complicated and the temperature is not suitable for control. and costly
Shortening the pre-oxidation time is the key to reducing the production cost of carbon fiber, but the short time will aggravate the skin-core structure, and the carbonization stage is prone to produce large voids and defects, resulting in a decrease in the mechanical properties of carbon fiber
Reduce the pre-oxidation temperature and prolong the pre-oxidation time, the skin-core structure of the pre-oxidized fiber is not obvious, which is beneficial to improve the performance of carbon fiber, but reduces the production efficiency
Therefore, no excellent pre-oxidation process has been developed so far.

Method used

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  • Method for preparing pre-oxidized polyacrylonitrile fiber by melt spinning
  • Method for preparing pre-oxidized polyacrylonitrile fiber by melt spinning
  • Method for preparing pre-oxidized polyacrylonitrile fiber by melt spinning

Examples

Experimental program
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Effect test

Embodiment 1

[0031] First, the polyacrylonitrile preoxidation catalyst cobalt dichloride is dissolved in the ionic liquid with a weight ratio of 1: 100, and the dry polyacrylonitrile powder is added, wherein the weight ratio of the polyacrylonitrile powder to the ionic liquid is 1: 1; The mixture that obtains joins in twin-screw spinning machine and carries out melt spinning and simultaneously passes into air to the melting section of twin-screw spinning machine, and wherein, air flow rate is 1ml / min, screw speed is 40r / min, feed section temperature The temperature of the plasticizing section is 170°C, the temperature of the plasticizing section is 185°C, the temperature of the melting section is 185°C, the length-to-diameter ratio of the spinneret is 1:3, and the hole diameter is 0.5mm; the spun silk is directly stretched by dry heat, and the stretching temperature is 110°C, the total stretching ratio is 4 times, the stretched fiber is washed with water at 70°C, and then heat-set in dry ho...

Embodiment 2

[0033] First, the polyacrylonitrile preoxidation catalyst cobalt sulfate is dissolved in the ionic liquid with a weight ratio of 0.01: 100, and the dry polyacrylonitrile powder is added, wherein the weight ratio of the polyacrylonitrile powder to the ionic liquid is 1: 1; the obtained The mixture is added to the twin-screw spinning machine for melt spinning and oxygen is passed into the melting section of the twin-screw spinning machine at the same time, wherein the oxygen flow rate is 5ml / min, the screw speed is 120r / min, and the temperature of the feed section is 185 ℃, the temperature of the plasticizing section is 220℃, the temperature of the melting section is 220℃, the aspect ratio of the spinneret is 1:3, and the hole diameter is 0.5mm; the spun silk is directly stretched by dry heat, and the stretching temperature is 140℃ , the total stretching ratio is 6 times, the stretched fiber is washed with water at 90°C, and then heat-set in dry hot air at 150°C to obtain a polya...

Embodiment 3

[0035] First, potassium permanganate particles and [BMIM]Cl were mixed evenly in a three-necked flask at a weight ratio of 0.01:100 to completely dissolve potassium permanganate, and then dry polyacrylonitrile powder and [BMIM]Cl were mixed by weight The ratio of 1: 1 is uniformly mixed in a high-speed mixer, then transferred to a twin-screw spinning machine for melt spinning, and the flow of oxygen is 2ml / min for the melting section of the twin-screw. The screw speed of the twin-screw spinning machine is 50r / min, the temperature of the feed section is set to 185°C, the temperature of the plasticizing section is 190°C, the temperature of the melting section is 185°C, the length-to-diameter ratio of the spinneret is 1:3, and the hole diameter is 0.5 mm, the spun filaments are subjected to dry heat stretching. The stretching temperature is 120°C, and the total stretching ratio is 45 times. The stretched fibers are washed with water at 80°C, and then heat-set in dry hot air at 120...

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Abstract

The invention provides a method for preparing pre-oxidized polyacrylonitrile fiber by melt spinning, which is characterized in that, the specific steps are as follows: the first step: the first step: dissolving pre-oxidation catalyst of polyacrylonitrile in the ionic liquid, adding polyacrylonitrile powder; the second step: adding the mixture obtained in the first step into a double-screw rod spinning machine for carrying out melt spinning and simultaneously infusing oxygen-containing gas for the melting segment of the double-screw rod spinning machine; the third step: directly dry heat stretching spun thread, washing stretched fibre in water at 70-90 DEG C, then obtaining pre-oxidized polyacrylonitrile fiber by thermosetting. The method provided by the invention realizes controllably producing pre-oxidized polyacrylonitrile with low cost, and reduces production cost and core-skin structure in pre-oxidation stage, thereby the method can be used for producing high-performance carbon fibre.

Description

technical field [0001] The invention relates to a method for preparing polyacrylonitrile preoxidized fibers by melt spinning, and belongs to the technical field of polyacrylonitrile melt spinning. Background technique [0002] Carbon fiber has a series of excellent properties such as low density, high strength, high modulus, high temperature resistance, corrosion resistance, friction resistance, fatigue resistance, etc. It is widely used in high-tech industrial fields, especially in the aerospace field with great application prospects . In the manufacturing process of polyacrylonitrile-based carbon fibers, pre-oxidation treatment is a key step and is the longest process, and its structural transformation largely determines the structure and properties of the final carbon fiber. Since the pre-oxidation process is a period of severe structural transformation, defects are easily generated, resulting in a decrease in the mechanical properties of carbon fibers. Therefore, the s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D01F6/54D01D5/08D01F9/22
Inventor 余木火荣怀苹韩克清王兆华滕翠青张毅炜田银彩邓智华董勤礼
Owner DONGHUA UNIV
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