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Method for preparing micro-nano cellulose with ultra-low crystallinity

A technology of micro-nano cellulose and crystallinity, which is applied in the fields of chemistry, environmental engineering, and agriculture. It can solve the problems of high accessibility and reactivity, low reactivity, and high crystallinity, so as to expand the scope of use and enhance reactivity. , the effect of water retention value improvement

Inactive Publication Date: 2012-10-03
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the cellulose prepared by the method of the present invention has ultra-low crystallinity, high accessibility and reactivity, which overcomes the defects of high crystallinity, low accessibility and low reactivity of cellulose prepared by traditional methods, Can be widely used in various cellulose application fields

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 115 grams of pulp to 1L of 64% (wt.) sulfuric acid aqueous solution, hydrolyze at 45°C for 45 minutes, and then dilute with a large amount of water to terminate the reaction; the obtained reactant is washed with water until the cellulose cannot be precipitated, then centrifuged and washed until neutral, and crystallization is obtained Higher degree of micro-nano cellulose crystals; add micro-nano cellulose crystals to 4% (wt.) NaOH aqueous solution, put in the refrigerator, and freeze at -5°C for 24 hours; after the cellulose is completely dissolved, pour it into a large amount of water , regenerate the cellulose, and wash away the residual alkali with distilled water; homogenize the washed neutral cellulose in a high-pressure homogenizer to obtain micro-nano cellulose with low crystallinity.

Embodiment 2

[0023] Add 115 grams of pulp to 1L of 28% (wt.) hydrochloric acid aqueous solution, hydrolyze at 80°C for 45 minutes, then dilute with a large amount of water to terminate the reaction; wash the obtained reactant with water until the cellulose cannot be precipitated, then centrifuge and wash until neutral, and obtain crystals Higher degree of micro-nano cellulose crystals; add micro-nano cellulose crystals to 8% (wt.) LiOH aqueous solution, put them in the refrigerator, and freeze at -5°C for 24 hours; after the cellulose is completely dissolved, pour it into a large amount of ethanol , regenerate the cellulose, and wash away the residual alkali with distilled water; homogenize the washed neutral cellulose in a high-pressure homogenizer to obtain micro-nano cellulose with low crystallinity.

Embodiment 3

[0025] Put 115 grams of pulp into a pulverizer to pulverize, pass through a 100-mesh sieve, and vacuum-dry in a vacuum oven at 105°C for 24 hours to obtain micronano cellulose crystals; add the pulverized cellulose powder to 1L of 30% (wt.) sodium hypochlorite aqueous solution , hydrolyze at 50°C for 48 hours, and then dilute with a large amount of water to terminate the reaction; the obtained reactant is washed with water until the cellulose cannot be precipitated, then centrifuged and washed until neutral, and micro-nano cellulose crystals with a high degree of crystallization are obtained; the micro-nano cellulose The crystals were added to 12% (wt.) KOH aqueous solution, put into the refrigerator, and frozen at 0°C for 8 hours; after the cellulose was completely dissolved, poured into a large amount of methanol to regenerate the cellulose, and washed with distilled water to remove residual alkali; Neutral cellulose undergoes high-speed shearing and grinding to obtain micro-...

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Abstract

The invention discloses a method for preparing a micro-nano cellulose with ultra-low crystallinity, which comprises the following steps of: allowing a micro-nano cellulose crystal with higher crystallinity to be fully dissolved in a dissolution system of the cellulose and reproducing; changing the cellulose into a loose cellulose II structure; and through mechanical treatment, further destructing a crystalline structure of the cellulose to obtain the micro-nano cellulose with ultra-low crystallinity. Amorphous cellulose intermolecular and intramolecular hydrogen bonding interaction is weakened, the majority of hydroxyl groups on a molecular chain are exposed to enhance the degree of availability and reaction activity of the cellulose, and the water retention value is also increased. Accordingly, the cellulose prepared by the method provided by the invention has ultra-low crystallinity, and extremely high degree of availability and reaction activity, overcomes the defects that the cellulose prepared by the traditional method has high crystallinity and low degree of availability and reaction activity, and can be widely used in application fields of various celluloses.

Description

technical field [0001] The invention belongs to the fields of chemistry, agriculture and environmental engineering, relates to the technical field of natural polymers and their preparation, and in particular to a method for preparing ultra-low crystallinity micro-nano cellulose. Background technique [0002] Cellulose is one of the most abundant natural polymer materials in nature. It is a cheap renewable resource with the characteristics of degradability, environmental friendliness and good biocompatibility. Its application and development are becoming more and more extensive. attention. However, there are a large number of hydrogen bonds in and between the molecules of cellulose, which has a high degree of crystallinity, and a large number of reactive hydroxyl groups inside the cellulose are blocked, thus hindering the contact of chemical reagents or the surface of the cellulose, making the cellulose accessible. Low concentration, very difficult to dissolve. To improve t...

Claims

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Application Information

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IPC IPC(8): C08B15/08
Inventor 丁恩勇薛彬黄丽浈
Owner SOUTH CHINA UNIV OF TECH
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