Preparation method of aqueous dispersion of aramid nano-fibers

An aqueous dispersion and nanofiber technology, applied in the field of nanomaterials, can solve the problems of low solid content of aramid nanofiber aqueous dispersion, limited application range of aramid fibers, and high requirements for construction conditions, and achieves high aspect ratio, The effect of small diameter and excellent heat resistance

Active Publication Date: 2019-10-22
SINOCHEM HIGH PERFORMANCE FIBER MATERIALS CO LTD +1
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  • Abstract
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  • Claims
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Problems solved by technology

However, the nano-aramid fibers prepared by this method can only exist in the oily dispersion system of strong alkali. When the dispersion system becomes weakly alkaline or neutral, the nitrogen atoms regain hydrogen atoms, and the aramid fibers will reassemble. Greatly limit the application range of aramid fiber
[0004] In the invention with the application number CN201710630413.1, supercritical carbon dioxide fluid technology is used to modify and prepare modified aramid fibers, but this method is suitable for laboratory environments, and the actual construction has high requirements for construction conditions, and its Aramid fibers are produced instead of aramid nanofibers
[0005] And the publication number is that the aramid nanofiber aqueous dispersion in CN108316038A has low solid content, low production efficiency and long time consumption

Method used

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[0028] The preparation method of an aqueous dispersion of aramid fiber nanofibers provided by the invention comprises the steps of: weighing potassium hydroxide and para-aramid polymers according to a mass ratio of 0.5-2. Then the two substances are added to the dimethyl sulfoxide solution, and dissolved at 30-130°C for 2-4 days to obtain a dark red aramid fiber solution. Then under high-speed shearing conditions, add deionized water at a rate of 20-200ml / h, and then perform dialysis and high-pressure homogenization to obtain an aqueous dispersion of aramid nanofibers. After concentration, the aqueous dispersion of aramid nanofibers The body solids content can be increased to 4%. Among them, the high-speed shear rate is about 8000 rpm, the molecular weight cut-off of dialysis is 8000-14000, the high-pressure homogenization pressure is 50-150Mpa, and the homogenization is performed 2-3 times.

[0029] The present invention will be described in detail below in combination with ...

Embodiment 1

[0031] The preparation steps of a kind of aramid fiber nanofiber aqueous dispersion of the present embodiment are as follows: Weigh 4g aramid polymer and 2g potassium hydroxide respectively, then add the two substances into 170ml dimethyl sulfoxide solution, and Add 5ml of deionized water. Then dissolve at 80° C. for 2 days at a speed of 600 rpm to obtain a dark red 2% aramid fiber solution. Then, while shearing at a high speed, deionized water was added dropwise at a rate of 50 ml / h to dilute to 0.5%, and then dialysis was performed to remove dimethyl sulfoxide and other impurity ions. Finally, after three times of 150Mpa high-pressure average treatment, an aqueous dispersion of aramid fiber nanofibers with a solid content of 0.5 wt% was obtained, with a mass concentration of 5 mg / ml.

Embodiment 2

[0033] The preparation steps of a kind of aramid fiber nanofiber aqueous dispersion of the present embodiment are as follows: Weigh 4g aramid polymer and 2g potassium hydroxide respectively, then add the two substances into 170ml dimethyl sulfoxide solution, and Add 5ml of deionized water. Then dissolve at 80° C. for 2 days at a speed of 800 rpm to obtain a dark red 2% aramid fiber solution. Then, while high-speed shearing, deionized water was added dropwise at a rate of 100ml / h to dilute to 0.5%, and then dialysis was performed to remove dimethyl sulfoxide and other impurity ions. Finally, after three times of 150Mpa high-pressure average treatment, an aqueous dispersion of aramid fiber nanofibers with a solid content of 0.5 wt% was obtained.

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Abstract

The invention discloses a preparation method of an aqueous dispersion of aramid nano-fibers. The method comprises the following steps: adding an aramid fiber, potassium hydroxide, a cosolvent and a solvent into a container, and performing heating and stirring for dissolving to obtain aramid nano-fibers dispersed in the KOH/DMSO system; adding deionized water to the dispersed aramid nano-fiber dispersion under the action of high-speed shearing stirring to obtain an aramid nano-fiber dispersion dispersed in the KOH/DMSO/H2O system; immersing the aramid nano-fiber dispersion in deionized water, and carrying out dialysis treatment to obtain an aqueous dispersion of aramid fibers; and carrying out high-pressure homogenization treatment on the aqueous dispersion of aramid fibers to obtain the uniform and stable aqueous dispersion of aramid nano-fibers. The aramid nanofibers prepared in the invention have the advantages of small diameter, high length-diameter ratio and excellent heat resistance, can be stably dispersed in the aqueous system, and has a greatly expanded application range.

Description

technical field [0001] The invention belongs to the technical field of nanometer materials, in particular to a method for preparing an aqueous dispersion of aramid fiber nanofibers. Background technique [0002] Aramid fiber was first developed by Dupont in 1968, and officially produced in 1972, with the registered trademark of Kevlar. The full name of aramid is poly-p-phenylene terephthalamide (PPTA), also known as para-aramid, which has excellent properties such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight. It is 5 to 6 times that of steel wire, its modulus is 2 to 3 times that of steel wire or glass fiber, its toughness is 2 times that of steel wire, and its weight is only about 1 / 5 of that of steel wire. melt. Therefore, Kevlar has high specific strength, high specific modulus of elasticity and high heat resistance, and exhibits high tensile strength and tensile modulus. It is an ideal reinforcing mater...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/07C08L77/10
CPCC08J3/07C08J2377/10
Inventor 朱俊强曹煜彤顾克军曹美荣徐蔼莹施利毅袁帅王庆同
Owner SINOCHEM HIGH PERFORMANCE FIBER MATERIALS CO LTD
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