Preparation method of high-carboxyl-functionality cellulose nanocrystals

A technology of cellulose and functionality, applied in the field of natural polymer chemistry, can solve the problems of limiting the application of cellulose nanocrystals, poor interface interaction, poor dispersion, etc., to improve interfacial compatibility, improve dispersion, and enhance mechanical properties Effect

Inactive Publication Date: 2017-05-24
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high specific surface area, hydrophilicity, and intramolecular and intermolecular hydrogen bonding, cellulose nanocrystals are often prone to self-aggregation and poor dispersion, resulting in not only a low addition amount, but also a relatively weak interfacial interaction between the two phases. Poor, which limits the application of cellulose nanocrystals, therefore, the surface modification method of cellulose nanocrystals is imminent

Method used

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  • Preparation method of high-carboxyl-functionality cellulose nanocrystals
  • Preparation method of high-carboxyl-functionality cellulose nanocrystals
  • Preparation method of high-carboxyl-functionality cellulose nanocrystals

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] (1) According to 0.5 parts of hemp fiber, 0 part of 4-diaminopyridine, and 0.5 part of acetic anhydride, select hemp fiber and acetic anhydride, dissolve hemp fiber in 20ml of pyridine, crush the cells for 1min, pour into a three-necked flask, and heat at 75°C , Stir and react for 30 minutes under the protection of nitrogen; dissolve acetic anhydride in 30ml of pyridine, seal with plastic wrap, then ultrasonic for 5 minutes, and stir magnetically at room temperature for 15 minutes, and the acetic anhydride is fully dissolved. In a three-necked flask of cellulose raw material, react under nitrogen protection at 45°C for 5h;

[0033] (2) centrifuge after the end of the reaction, pour off the supernatant, and the precipitated product is successively washed by pyridine, 95% ethanol, distilled water, 2wt% sodium carbonate solution, distilled water, 95% ethanol, and acetone, so as to obtain the surface polycarboxylated fiber cellulose nanocrystals, and then freeze-dried to ob...

Embodiment 2

[0036] (1) According to 0.6 parts of cellulose nanocrystals, 0 parts of 4-diaminopyridine, and 1 part of ethylenediaminetetraacetic dianhydride, select cellulose nanocrystals and ethylenediaminetetraacetic dianhydride, and dissolve the cellulose nanocrystals in In 30ml of pyridine, crush the cells for 2 minutes, pour into a three-necked flask, stir and react for 30 minutes at 75°C under nitrogen protection; dissolve ethylenediaminetetraacetic acid dianhydride in 45ml of pyridine, seal with plastic wrap, then sonicate for 10 minutes, and stir magnetically for 15 minutes at room temperature Finally, the ethylenediaminetetraacetic acid dianhydride was fully dissolved, and the acid anhydride mixture was added dropwise into the three-necked flask containing the cellulose raw material under the protection of nitrogen atmosphere, and reacted for 12 hours under the protection of nitrogen at 55°C;

[0037] (2) centrifuge after the end of the reaction, pour off the supernatant, and the p...

Embodiment 3

[0040] (1) According to 0.7 parts of microcrystalline fiber, 0 parts of potassium carbonate, and 10 parts of diethylenetriaminepentaacetic acid, select microcrystalline fiber and diethylenetriaminepentaacetic acid, and dissolve the microcrystalline fiber in 40ml of nitrogen-nitrogen dimethyl formaldehyde In amide, the cells were crushed for 3 minutes, poured into a three-necked flask, stirred and reacted for 30 minutes at 75°C under nitrogen protection; diethylenetriaminepentaacetic acid was dissolved in 50ml of nitrogen-nitrogen dimethylformamide, sealed with plastic wrap, and then ultrasonicated for 10 minutes. After 15 minutes of magnetic stirring at room temperature, the diethylenetriaminepentaacetic acid was fully dissolved, and the acid anhydride mixture was added dropwise into the three-necked flask containing the cellulose raw material under the atmosphere of nitrogen protection, and reacted under nitrogen protection at 65°C for 24 hours;

[0041] (2) centrifuge after t...

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Abstract

The invention belongs to the field of natural high polymer chemistry, and particularly relates to a preparation method of high-carboxyl-functionality cellulose nanocrystals. The method comprises the following steps: (1) dissolving a cellulose raw material in an organic solvent, pulverizing cells, and mixing with a catalyst to carry out pre-reaction; (2) adding acid anhydride into the organic solvent, sealing, applying ultrasonic, and stirring until the solid is sufficiently dissolved; (3) in a nitrogen protective atmosphere, dropwisely adding the solution obtained in the step (2) into the solution in the step (1), and continuing reaction for some time; and (4) after the reaction finishes, centrifugating, and washing the precipitate to obtain the powdery surface-polycarboxylated cellulose nanocrystals. The cellulose raw material is proportionally mixed with the catalyst and acid anhydride to prepare the surface-carboxylated cellulose nanocrystals by a one-step process. The prepared cellulose nanocrystals have abundant carboxyls on the surface, and have great application potential in the fields of high-performance nano composite materials, biological medical materials, cosmetics, food and the like.

Description

technical field [0001] The invention belongs to the field of natural polymer chemistry, and in particular relates to a preparation method of cellulose nanocrystals with high carboxyl functionality. Background technique [0002] Due to their excellent intrinsic properties, including nanoscale size, unique morphology, high specific surface area, low specific gravity and high mechanical strength, etc., as well as a wide range of sources, simple preparation, easy handling, renewable and degradable, the surface of cellulose nanocrystals The richness of hydroxyl groups and other advantages have attracted extensive attention in the fields of nanocomposites, biomedicine, and cosmetics. However, due to the high specific surface area, hydrophilicity, and intramolecular and intermolecular hydrogen bonding, cellulose nanocrystals are often prone to self-aggregation and poor dispersion, resulting in not only a low addition amount, but also a relatively weak interfacial interaction betwee...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08B15/04
CPCC08B15/04
Inventor 黄进张燕洁林宁夏涛
Owner WUHAN UNIV OF TECH
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