What are the preparation methods for Attached, detailed process introduction and application prospect analysisnanocellulose ?

Nanocellulose preparation methods have been a hot topic in the fields of materials science and green chemical engineering in recent years. Nanocellulose has the advantages of lightweight, high strength, renewable, biodegradable, etc., and is widely used in composite materials, biomedicine, coatings, food packaging and other industries. This article will focus on the keyword ' preparation method of nanocellulose ' , systematically introduce its main classification, production process, and various technical characteristics, and analyze its application and development prospects.

1. What is nanocellulose?

Nanocellulose refers to a functional material with a particle size between 10 and 100 nanometers and obtained by nano-treating treatment of natural According to the different morphological structure and preparation method, it is often divided into three types:cellulose .

Cellulose nanocrystals ( CNC )

Cellulose nanofibers ( CNF )

Bacterial cellulose ( BC )

2. Detailed explanation of the preparation method of nanocellulose

1. Preparation method of CNC: acid hydrolysis method

Acid hydrolysis is for preparing cellulose nanocrystals ( the most commonly used method CNC ).

The process flow is as follows :

Use wood pulp and cotton pulp as raw materials;

Add 64% sulfuric acid solution for hydrolysis to selectively remove the amorphous area;

Wash and neutralize and centrifuge;

Ultrasonic dispersion and drying to obtain nanocrystals.

advantage :

High crystallinity of CNC ;

Strong thermal stability;

The surface is negatively charged and easily dispersed in water.

Application : Widely used in plastic reinforcement, conductive materials, inks, coatings and other fields.

2. Preparation method of CNF: Mechanical dissociation and chemical assisted combination

CNF is mainly produced by mechanical shearing methods, such as high-pressure homogenization, ultra-fine grinding, high-speed stirring, etc.

Commonly used assistive technologies :

TEMPO oxidation method : selectively oxidize the hydroxyl group on the cellulose surface in the TEMPO/NaClO/NaBr system to make it negatively charged and facilitate fiber dissociation;

Enzymatic solution : Use cellulase to gently degrade, improve fiber dissociation efficiency and reduce energy consumption.

Features :

Good flexibility and high aspect ratio;

Can form a transparent gel;

Suitable for film, packaging, biostent and other products.

3. Preparation of bacterial cellulose (BC): microbial fermentation method

BC is a natural nanocellulose synthesized by fermentation in glucose or sucrose medium by specific bacterial species such as Komagataeibacter .

Process Features :

It is produced directly through microorganisms without plant materials;

Regular structure and high purity;

It can be used in high-end fields such as medical dressings and artificial blood vessels.

3. Comparison of preparation methods for different nanocellulose

project	CNC (acid hydrolysis)	CNF (Mechanical + Chemistry)	BC (Biofermentation)
Source of raw materials	Wood pulp, cotton pulp	Agricultural waste, wood pulp	Glucose, carbon source
Process difficulty	medium	Higher	高
cost	medium	Higher	Very high
Product Features	High crystallinity, regular	Strong flexibility and easy to form film	Three-dimensional structure, ultra-high purity
Application direction	Functional composite materials, batteries	Film materials, food packaging	Medical biological materials

4. Common problems in nanocellulose preparation technology

1. What should I do if nanocellulose is poorly dispersible?
Solution: Its hydrophilicity can be improved through surface modification (such as TEMPO oxidation), or the dispersion effect can be enhanced by using surfactants.

2. Is the production cost of nanocellulose high?
At present, it is still relatively high, and the main sources of cost include: raw material purification, acid treatment, equipment energy consumption, etc. With the development of green and low-consumption technologies, costs are expected to be further reduced in the future.

3. Is nanocellulose environmentally friendly?
Yes. Nanocellulose is derived from natural cellulose and is a degradable, non-toxic and sustainable green material.

V. Application and Prospect of Nanocellulose

With the advancement of the ' carbon peak and carbon neutrality ' strategy, nanocellulose, as a green high-performance material, has great development potential.

The main application directions include :

Environmentally friendly packaging materials;

Degradable plastic reinforcement;

Medical dressings and tissue engineering stents;

Food additives and plastic wrap;

Flexible electronic devices, supercapacitor materials.

According to a research report on China's materials industry, the annual growth rate of nanocellulose in the future is expected to exceed 20%.。

6. Conclusion

The preparation methods of nanocellulose include acid hydrolysis, mechanical dissociation, TEMPO oxidation, biofermentation and other routes, each with its advantages and applicable scenarios. With the continuous breakthroughs in the direction of greening, low-cost and high-performance, nanocellulose is expected to be industrialized in more industrial fields.

Keyword summary : nanocellulose preparation, cellulose nanocrystals, TEMPO oxidation method, CNF 、CNC 、BC , biodegradable materials, nanomaterials, green materials, renewable resources.