Method for preparing cellulose nanocrystals by hydrolyzing cellulose with eutectic solvent

A technology of deep eutectic solvent and nanocrystals, which is applied in the field of preparation of natural polymer materials, can solve the problems of low product thermal stability, low yield, cumbersome overall steps, etc., to achieve increased yield, lower reaction temperature, simplified The effect of the preparation process

Inactive Publication Date: 2020-12-01
TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this method solves the problems of low yield and low product thermal stability caused b

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  • Method for preparing cellulose nanocrystals by hydrolyzing cellulose with eutectic solvent

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Effect test

Embodiment 1

[0020] Add 40g of citric acid and 45g of betaine into a 250mL three-necked flask at 25°C, and add 5g of distilled water into it, then heat it with an oil bath, raise the temperature to 50°C, stir mechanically for 10min, and the stirring speed is 100r / min , form a deep eutectic solvent, then add 5g of sulfuric acid with a mass concentration of 98% into the there-necked flask, stir for 5min, then add 1g of bleached eucalyptus pulp, continue to stir at 55°C for 5h, and react with 300g of 90°C distilled water Dilute the mixture, then centrifuge at 10,000r / min for 5min while it is hot, pour out the supernatant and keep the precipitate, then disperse the obtained precipitate with 100g of distilled water, centrifuge at 10,000r / min for 5min, and repeat the process. Centrifugal washing with distilled water was performed three times, and the solid obtained after washing was freeze-dried, and the yield of cellulose nanocrystals was 74.5%. The temperature at which the resulting product lo...

Embodiment 2

[0022] Add 40g of citric acid and 50g of betaine into a 250mL three-neck flask at 25°C, add 5g of distilled water into it, then heat it with an oil bath, raise the temperature to 55°C, stir mechanically for 10min, and the stirring speed is 300r / min, Form a deep eutectic solvent, then add 10 g of sulfuric acid with a mass concentration of 98% in the there-necked flask, stir for 5 min, then add 10 g of dissolving slurry, continue stirring at 55 ° C for 4 h, and dilute the reaction mixture with 700 g of 60 ° C distilled water, Then centrifuge at a speed of 10000r / min for 8min while it is hot, pour out the supernatant and keep the precipitate, then disperse the obtained precipitate with 800 g of distilled water, then centrifuge at a speed of 10000r / min for 8min, repeat this centrifugation with distilled water The washing process was performed 5 times, and the solid obtained after washing was freeze-dried, and the yield of the obtained nanocellulose crystal was 78.0%. The temperatu...

Embodiment 3

[0024] Add 40g of citric acid and 40g of betaine into a 250mL three-neck flask at 30°C, add 10g of distilled water to it, then heat it in an oil bath, raise the temperature to 60°C, stir mechanically for 10min, and the stirring speed is 200r / min, Form a deep eutectic solvent, then add 10 g of sulfuric acid with a mass concentration of 98% to the there-necked flask, stir for 5 min, then add 3 g of cotton pulp, continue stirring at 60 ° C for 2.5 h, and dilute the reaction mixture with 300 g of 65 ° C distilled water , then centrifuge at 8000r / min for 5min while hot, pour out the supernatant and keep the precipitate, then disperse the obtained precipitate with 600g of distilled water, then centrifuge at 8000r / min for 5min, repeat this centrifugation with distilled water The washing process was performed 5 times, and the solid obtained after washing was spray-dried, and the yield of the obtained nanocellulose crystal was 81.5%. The temperature at which the resulting product loses...

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Abstract

The invention relates to a method for preparing cellulose nanocrystals by hydrolyzing cellulose with a eutectic solvent, and belongs to the field of preparation of natural polymer materials. The cellulose nanocrystal is an acidic eutectic system consisting of 40 parts by mass of citric acid, 40-50 parts by mass of betaine, 5-10 parts by mass of distilled water and 5-10 parts by mass of sulfuric acid and carrying out catalytic hydrolysis on 1-10 parts by mass of cellulose slurry, wherein the reaction time is 2-6 hours, and the reaction temperature is 50-65 DEG C; the reaction conditions are mild, and the operation is simple. The one-step preparation of the cellulose nanocrystals by using the acidic eutectic solvent is realized, the reaction efficiency of preparing the cellulose nanocrystalsby using the eutectic system is effectively improved, and the product properties of the cellulose nanocrystals are improved. The prepared cellulose nanocrystal has good thermal stability and high crystallinity, and is stable in dispersion in water.

Description

technical field [0001] The invention relates to the field of preparation of natural polymer materials, in particular to a method for preparing cellulose nanocrystals by hydrolyzing cellulose with a deep eutectic solvent. Background technique [0002] As a natural polymer material that widely exists in nature, cellulose has the characteristics of biodegradability, chemical modification, and renewability. In recent years, research on nanocellulose has made the utilization of cellulose more extensive and abundant. Due to the existence of the special structure of the crystalline region and the amorphous region of cellulose, the preparation and application of nanocellulose have developed in a variety of ways. [0003] Cellulose nanocrystals (CNCs) possess biodegradability, high strength, low density, high crystallinity, high aspect ratio, and unique optical properties. In addition, the polyhydroxyl structure on the surface of CNCs is easier to further modify, which can make it ...

Claims

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Application Information

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IPC IPC(8): C08B15/02
CPCC08B15/02
Inventor 张筱仪解洪祥孙琳司传领陈佳宁王绪美
Owner TIANJIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
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