Method for preparing nano celluloses through high-pressure homogenizing and low-temperature cooling

A nanocellulose, high-pressure crushing technology, applied in the direction of raw material separation, can solve the problems of affecting stability, material agglomeration, and high material temperature, and achieve the effect of improving dimensional stability and overcoming flocculation.

Inactive Publication Date: 2011-10-19
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because there is no effective temperature control method, the temperature of the material after ho

Method used

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  • Method for preparing nano celluloses through high-pressure homogenizing and low-temperature cooling
  • Method for preparing nano celluloses through high-pressure homogenizing and low-temperature cooling
  • Method for preparing nano celluloses through high-pressure homogenizing and low-temperature cooling

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Example 1, dispersing 2g of fiber raw material in an aqueous sulfuric acid solution with a mass fraction of 10 to 15%, the mass ratio of the fiber raw material to the aqueous sulfuric acid solution is 1:25 to 1:50, and kept at a temperature range of 20 to 60°C. 2h, obtain the aqueous solution of sulfuric acid dispersed with fiber raw materials; add distilled water to the above aqueous solution to dilute, centrifuge, circulate dialysis and filter, add 1% maleic anhydride to the obtained precipitate, and carry out high-pressure crushing with a homogenizer 4 times , the crushing pressure is 1000-1200 bar, low-temperature cooling is carried out during the crushing process to obtain nanocellulose colloid, and then centrifugal separation and freeze-drying are carried out to obtain the product.

Embodiment 2

[0012] Example 2, dispersing 2g of fiber raw material in an aqueous sulfuric acid solution with a mass fraction of 10 to 15%, the mass ratio of the fiber raw material to the aqueous sulfuric acid solution is 1:25 to 1:50, and kept at a temperature range of 20 to 60°C. 4h, obtain the aqueous solution of sulfuric acid dispersed with fiber raw materials; add distilled water to the above-mentioned aqueous solution for dilution, centrifugal separation, and circular dialysis filtration, add 2% maleic anhydride to the obtained precipitate, and perform high-pressure crushing with a homogenizer for 8 times , the crushing pressure is 1000-1200 bar, low-temperature cooling is carried out during the crushing process to obtain nanocellulose colloid, and then centrifugal separation and freeze-drying are carried out to obtain the product.

Embodiment 3

[0013] Example 3, dispersing 2g of fiber raw material in an aqueous sulfuric acid solution with a mass fraction of 15 to 20%, the mass ratio of the fiber raw material to the aqueous sulfuric acid solution is 1:25 to 1:50, and kept at a temperature range of 20 to 60°C. 6h to obtain an aqueous solution of sulfuric acid dispersed with fiber raw materials; add distilled water to the above-mentioned aqueous solution for dilution, centrifugal separation, and circular dialysis filtration; add 1% acetic anhydride to the obtained precipitate, and perform high-pressure crushing with a homogenizer for 16 times. The crushing pressure is 1000-1200 bar, low-temperature cooling is carried out during the crushing process to obtain nano-cellulose colloid, and then centrifugal separation and freeze-drying are carried out to obtain the product.

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Abstract

The invention relates to a method for preparing nano celluloses through high-pressure homogenizing and low-temperature cooling. The method comprises the following steps: dispersing the raw fibers in a sulfuric acid aqueous solution with the mass fraction of 10-20%, maintaining the raw fibers in the aqueous solution for 2-6 hours at 20-60 DEG C, adding a dispersing agent after dilution, centrifugal separation and cyclic dialysis, utilizing a high-pressure homogenizer for high-pressure homogenizing, simultaneously carrying out low-temperature cooling in the process of high-pressure homogenizingto obtain nano cellulose colloids and obtaining the nano celluloses through centrifugal separation and freeze drying, wherein the pressure is 1000-1200bar; and the cycle index is 4-16. The diameter and length of the obtained nano celluloses are respectively about 10-30nm and 300nm. The method has the beneficial effect of solving the following problems: the existing nano celluloses prepared by utilizing the homogenizers have wide and nonuniform diameter distribution; the fibers are interwoven in micron size; and the pressure and the temperature are raised in the process of high-pressure homogenizing.

Description

technical field [0001] The invention belongs to the preparation method of nanometer cellulose. Background technique [0002] Nanocellulose, also known as cellulose nanocrystals, is a type of rigid rod-shaped single crystal cellulose (whiskers), with a diameter of 1-100 nm and a length of tens to hundreds of nanometers. In some literature reports, nanocellulose is also called cellulose nanowhiskers, nanocrystals, micro-nanofibrils and so on. Nanocellulose has renewable properties, high crystallinity, high aspect ratio, high specific surface area and high transparency, etc., and has good application prospects in food, medicine, papermaking, textiles and other fields. [0003] Methods for preparing nanocellulose include hydrolysis, mechanical, biological, solvent, electrospinning, and ionic liquid dissolution. Among them, the high-pressure homogenization method is a common mechanical preparation method for preparing nanocellulose. During the high-pressure homogenization proc...

Claims

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Application Information

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IPC IPC(8): D21B1/30
Inventor 潘明珠周定国周晓燕梅长彤连海兰徐信武兰平
Owner NANJING FORESTRY UNIV
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