A method for preparing cellulose with a low degree of polymerization by freezing and grinding, and its products and applications

A technology with a low degree of polymerization and cellulose, applied in the field of cellulose materials, to achieve the effects of excellent non-volatility of reagents, appropriate degree of polymerization, and high yield

Active Publication Date: 2019-11-12
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But so far there is no relevant report on the preparation of low-polymerization cellulose by grinding treatment.

Method used

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  • A method for preparing cellulose with a low degree of polymerization by freezing and grinding, and its products and applications
  • A method for preparing cellulose with a low degree of polymerization by freezing and grinding, and its products and applications
  • A method for preparing cellulose with a low degree of polymerization by freezing and grinding, and its products and applications

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The cellulose raw material adopts wood pulp with a polymerization degree of 1700. First, the wood pulp is shredded, frozen in liquid nitrogen for 10 minutes, and then grinded for 10 minutes, 30 minutes, 60 minutes and 100 minutes respectively with a firing pin grinder. Liquid nitrogen maintains a low temperature environment. The degree of polymerization of the sample after grinding was tested using the national standard GB5888-86.

[0041] From figure 1 and figure 2 It can be seen that after grinding for 10 minutes, a white powder sample was obtained, with a yield of 99%, a degree of polymerization of 1399, and a particle size of 20-100 μm; after grinding for 30 minutes, a white powder sample was obtained, with a yield of 96%, a degree of polymerization of 970, and a particle size of 5-20 μm; after grinding for 60 minutes Finally, a white powder sample was obtained with a yield of 95%, a degree of polymerization of 540, and a particle size of 1-3 μm; after grinding f...

Embodiment 2

[0043] The cellulose raw material adopts white cotton fibrous combed cotton with a degree of polymerization of 4000. First, the combed cotton is frozen in dry ice for 30 minutes, and then the needle grinder is used to grind for 10 minutes, 20 minutes, 40 minutes and 80 minutes respectively. Dry ice maintains a low temperature environment. The degree of polymerization of the sample after grinding was tested using the national standard GB5888-86.

[0044] After grinding for 10 minutes, a white powder sample was obtained, with a yield of 99%, and a degree of polymerization of 3120; after grinding for 20 minutes, a white powder sample was obtained, with a yield of 98%, and a degree of polymerization of 2690; after grinding for 40 minutes, a white powder sample was obtained, with a yield of 96%, and a degree of polymerization of 1910 , the degree of crystallinity is close to 0; a white powder sample was obtained after grinding for 80 min, with a yield of 94% and a degree of polymer...

Embodiment 3

[0046] The cellulose raw material is microcrystalline cellulose with a degree of polymerization of 220 in white powder form. First, freeze the microcrystalline cellulose in liquid helium for 10 minutes, and then use a ball mill to grind it for 10 minutes, 20 minutes, 40 minutes, 60 minutes, 80 minutes, 100 minutes, and 120 minutes. , 150min and 180min, using liquid helium to maintain a low temperature environment during the grinding process. The degree of polymerization of the sample after grinding is tested using the national standard GB5888-86, and the degree of polymerization exceeds the test range by increasing the concentration of the sample solution to be tested.

[0047] After grinding for 10 minutes, a white powder sample was obtained, with a yield of 99%, and a degree of polymerization of 200; after grinding for 20 minutes, a white powder sample was obtained, with a yield of 98%, and a degree of polymerization of 181; after grinding for 40 minutes, a white powder sampl...

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Abstract

The invention discloses a method for preparing low polymerization degree cellulose through freezing and grinding, a product and application. The method comprises the steps that cellulose raw materialsare frozen, grinding is conducted through high-speed grinding equipment, and then the low polymerization degree cellulose is obtained. The method has the advantages that after freezing is conducted,cellulose polymer molecular chain movement is limited, the material brittleness is increased, cellulose macromolecular chains are likely to be broken and degraded in the grinding process, and the cellulose controllable in low polymerization degree, low crystallinity and even non-crystallizable polymerization degree can be obtained by changing the grinding time. Compared with traditional technologies such as an acid hydrolysis method, the method has the advantages of being rapid, efficient, simple, easy to implement and environmentally friendly and not producing a large amount of acid-containing waste liquor.

Description

technical field [0001] The invention relates to a cellulose material, in particular to a method for preparing cellulose with a low degree of polymerization by freezing and grinding, as well as its product and application. Background technique [0002] Cellulose is a linear natural macromolecule formed by combining β-D-glucose as a unit through 1,4 glycosidic bonds. The number of glucose units (AGU) of cellulose represents the degree of polymerization of cellulose. Natural cellulose has only a limited degree of polymerization. For example, the degree of polymerization of cotton cellulose is 6000-11000, the degree of polymerization of bagasse cellulose is about 3000, the degree of polymerization of ramie cellulose is 2000-2500, and the degree of polymerization of straw cellulose 400-700. The limited degree of polymerization greatly limits the application range of natural cellulose, and the degree of polymerization of cellulose can be regulated in a wide range of polymerizati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C5/00
CPCD21C5/00
Inventor 张晓程张军武进余坚张金明
Owner INST OF CHEM CHINESE ACAD OF SCI
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