Method for preparing nano-crystalline cellulose by multi-site oxidation method, and application thereof

A technology of nanocellulose and oxidation method, applied in the field of cellulose, can solve the problems of difficult recovery, expensive enzyme price, low reaction efficiency, etc., to reduce energy consumption and production cost, save the mechanical defibration step, and the process is simple. Easy to operate effect

Active Publication Date: 2017-05-31
NORTHEAST AGRICULTURAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Physical methods mainly include high-pressure homogeneous method, micro-jet method, disc grinding and ultrasonic method, etc. The main disadvantage of physical method is high energy consumption.
The chemical method uses inorganic strong acid and strong alkali to treat cellulose. Strong acid and strong alkali are corrosive to equipment and difficult to recycle. Waste liquid treatment is difficult and pollutes the environment.
Enzymes in biological methods are more expensive and the reaction conditions are harsh, and the reaction efficiency is low and the reaction time is long

Method used

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  • Method for preparing nano-crystalline cellulose by multi-site oxidation method, and application thereof
  • Method for preparing nano-crystalline cellulose by multi-site oxidation method, and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Add 500 ml of distilled water to a 1L beaker and wrap aluminum foil around it, add 2.5 mmol TEMPO, 40 mmol NaBr, 10 mmol NaIO 4 Add to beaker, also top with aluminum foil, and stir vigorously with a magnetic stirrer for 5 minutes. Remove the upper aluminum foil of the beaker, and add 5 g of commercial microcrystalline cellulose into the beaker while the magnetic stirrer is continuously stirring. After stirring evenly, 40 mmol of NaClO was slowly added. The stirring reaction was continued for 9 hours. During the reaction period, the pH value was adjusted once every 1.5 hours with 2M NaOH, so that the pH value of the reaction solution was maintained at about 10.5. After reacting for 9 hours, 5 mL of absolute ethanol was added to terminate the reaction, and the reaction time was 10 minutes. The reaction solution was centrifuged at 3000 rpm for 2 minutes, and the supernatant was precipitated with absolute ethanol at a volume ratio of 1:1.2, and then centrifuged. The pre...

Embodiment 2

[0033] Except that the reaction time is 4 hours, the rest of the operation method is the same as in Example 1, and nanocellulose with a rod-like shape observed by electron microscopy can also be obtained.

Embodiment 3

[0035] Nanocellulose was prepared from ordinary wood pulp. The hemicellulose and lignin in the wood pulp are first removed by general methods. Use glacial acetic acid and sodium chlorite to remove lignin, and use potassium hydroxide to remove hemicellulose to obtain purified cellulose. The following operation method is the same as in Example 1, and the shape of rod-shaped nanofibers observed by electron microscopy can be obtained. elements, but there are more network structures (such as figure 2 ).

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Abstract

The invention relates to a method for preparing nano-crystalline cellulose by a multi-site oxidation method. The method comprises the following steps: adding cellulose raw materials into reaction liquid, continuously stirring and reacting for 4.5-18.0 hours under a specific pH (Potential of Hydrogen) value; terminating reaction by absolute ethyl alcohol; carrying out centrifugation, precipitant sedimentation, cleaning solution washing and filter membrane suction filtration on a reaction product to obtain the nano-crystalline cellulose, wherein the reaction liquid is the mixture of TEMPO (2,2,6,6-Tetramethylpiperidinooxy), periodate, sodium bromide and sodium hypochlorite, oxidizing substances are TEMPO, periodate and sodium hypochlorite; the periodate selectively oxidizes C2 and C3 site hydroxyl, TEMPO selectively oxidizes a C6 site hydroxyl, and therefore, the method is called a multi-site oxidation method. The multi-site oxidization process of the method is finished in one step, processing time is short, and a technology is simple; oxidization and fiber separation processes are simultaneously carried out, a mechanical fiber separation step is not required, energy consumption is low, and a separation and purification method is simple and is suitable for industrial scale production. The prepared nano-crystalline cellulose has a wide application prospect in fields including nanocomposite materials, functional clothes, 3D printing and photoelectricity and the like.

Description

technical field [0001] The invention belongs to the technical field of cellulose, and in particular relates to a method for preparing nano-cellulose by a multi-site oxidation method and an application thereof. Background technique [0002] Nanocellulose is a kind of cellulose material whose size in one of the three dimensions is less than 100 nm. Nanocellulose has small size effect, surface interface effect and macroscopic quantum tunneling effect, and exhibits unique optical, electrical, magnetic and chemical properties. It has broad application prospects in the field of new material research and new technology. [0003] Due to the chemical crosslinking or physical entanglement of adjacent cellulose microfibrils, efficient nanofibrillation of cellulose has always been a difficulty in the high-value utilization of cellulose. The preparation methods of nanocellulose mainly include physical, chemical and biological methods. Physical methods mainly include high-pressure homo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H11/20C08B15/00
CPCC08B15/00D21H11/20
Inventor 孙孝政宋丽英裴熙祥
Owner NORTHEAST AGRICULTURAL UNIVERSITY
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