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Process for preparing polyvinyl alcohol -based active carbon fiber

A technology of polyvinyl alcohol fibers and activated carbon fibers, which is applied in the fields of fiber chemical characteristics, textiles and papermaking, etc., can solve the problems that fibers are easy to melt or burn, difficult to adsorb activated carbon fibers, and difficult to ensure complete and uniform impregnation, etc., to achieve Effect of heat resistance improvement

Inactive Publication Date: 2006-10-04
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is difficult to ensure complete and uniform impregnation in such a short time, so that the fibers are easy to melt or burn, and it is difficult to obtain activated carbon fibers with excellent adsorption properties.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The PVA fiber used in the present embodiment is the general industrial material fiber of wet manufacturing, and the average degree of polymerization of PVA is 1750 ± 50, and the surface linear density range of tow is 1.11-10dtex, and dry breaking strength is 2.5-5.5cN / dtex , The dry elongation at break is 11-38%, and the initial modulus is 23-50cN / dtex.

[0017] This embodiment is completed according to the following steps.

[0018] 1. Pre-oxidation

[0019] Intercept 3.6g of above-mentioned wet-spun PVA fibers, tie up the two ends of the fiber bundle to form a double-strand tow with a length of 26.7cm, and hang the two ends of the tow on a rectangular frame with a distance of 23cm from the two arms. On the two-stage spring, the elastic coefficient of the spring is 250N / m. Supporting the fiber with this spring frame not only applies tension to the fiber, but also allows the fiber to stretch the spring after being heated to a certain extent to offset part of the tensio...

Embodiment 2

[0049] Change the dehydrating agent composition to 3% (w / v) (NH 4 ) 2 HPO 4 and 7% (w / v) (NH 4 ) 2 SO 4 The mixed solution, under the same situation as in Example 1 under other conditions, obtain carbonized silk. The carbonized wire was placed in a tubular resistance furnace, and N was passed through at a flow rate of 60mL / min. 2 And after heating to 1100°C at a heating rate of 10°C / min, the nitrogen flow was stopped, and the flow rate of 40mL / min was changed to CO 2 Activated for 1.5 hours to prepare activated carbon fibers.

[0050] The obtained activated carbon fiber is a graphite-like crystal, and its pore structure is rich in micropores and a small amount of mesopores and macropores. The yield of activated carbon fiber is 8.7%, and the BET specific surface area is 1600m 2 / g, the methylene blue adsorption value is 151mg / g, and the iodine adsorption capacity is 1804mg / g.

Embodiment 3

[0052] The pre-oxidation and dehydration treatment were the same as in Example 1, and the carbonization time was changed to 0.5 hour to obtain carbonized filaments. The carbonized wire was placed in a tubular resistance furnace, and N was passed through at a flow rate of 60mL / min. 2 And after heating to 900°C at a heating rate of 10°C / min, the N 2 Before entering the electric resistance furnace, the stream flows through a round-bottomed flask filled with boiling distilled water to bring in water vapor, and is kept at this temperature for activation for 1.0 hour to prepare activated carbon fibers.

[0053] The obtained activated carbon fiber is a graphite-like crystal, and its pore structure is rich in micropores and a small amount of mesopores and macropores. The yield of activated carbon fiber is 27.3%, and the BET specific surface area is 919m 2 / g, the methylene blue adsorption value is 193mg / g, and the iodine adsorption capacity is 1825mg / g.

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Abstract

The preparation method for polyvinyl alcohol active carbon fiber comprises: heating the polyvinyl alcohol fiber in air at 180-220Deg with tension as 0.01-0.1cN / dtex to weightlessness rate till 7-12%; dipping with 5-15% drier, draining; heating in air at 240-270Deg with same tension till mass as 55-65% initial value; holding for 0.5-1h in 300+-10Deg air; heating the product in inert gas or static air to 900-1100Deg, then entering CO2, vapor or holding static air for 0.5-1.5h. This invention improves product performance, and has wide application.

Description

Technical field: [0001] The invention belongs to the technical field of preparation of high-efficiency adsorption and separation materials, in particular to a preparation method of polyvinyl alcohol (PVA)-based activated carbon fibers. Background technique: [0002] Japanese Open Patent Publication No. 59-187624 mentions a method of using PVA as a precursor to prepare activated carbon fibers. First, impregnate the PVA fibers with a dehydrating agent, then heat the fibers in hot air until the weight loss rate reaches 35%, and then carbonize and high temperature. Rapid activation treatment can produce active carbon fibers with a yield of 5.5-20.3 percent and an iodine adsorption capacity of 1020-1810 mg / g. For wet-spun PVA fibers, the components of the coagulation bath will inevitably dissolve when the dehydrating agent is impregnated, resulting in softening of the fibers, which are easy to melt and merge during the dehydration process, and cannot maintain the fibrous structur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/21
Inventor 俞汉青张淑娟郑家传
Owner UNIV OF SCI & TECH OF CHINA
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