Nanocellulose: a new green material originating from nature and empowering the future

In the wave of global green and low-carbon transformation and new material technology innovation, a new type of material derived from nature, high performance and environmentally friendly , is gradually entering the public eye and becoming the nanocellulose , ' green key ' to promote the upgrading of many industries . As the most abundant natural polymer material in nature, cellulose, after being modified at the nanoscale, has excellent properties that far exceed those of traditional materials. It shows broad application prospects in many fields such as lithium batteries, packaging, biomedicine, and papermaking, and also injects new momentum into the high-quality development of enterprises.

1. Understanding nanocellulose: the ' nano miracle ' gifted by nature

Nanocellulose ( Nanocellulose ) is a linear material with a diameter of several nanometers to tens of nanometers, a length of tens of nanometers to several micrometers, and a certain aspect ratio, which is made from natural cellulose and processed through physical, chemical or biological methods [1] . Its English name is nanocellulose . As an important research direction in the forestry discipline, it 20has gradually entered the field of scientific research and industry since the middle of the century . In 1949 , Sweden prepared nanocellulose with a diameter of 6about nanometers through acid hydrolysis of wood cellulose . 1995In 2008, France started research on cellulose nanocrystal-reinforced polymer materials. 2000After that, Chinese researchers also gradually carried out systematic research on raw material sources, preparation methods and applications [1]。

According to different morphologies and preparation methods, nanocellulose is mainly divided into two categories: cellulose nanocrystals ( CNC ) and cellulose nanofibrils ( CNF ) [1] . Among them, cellulose nanocrystals are obtained by chemical hydrolysis of natural cellulose. They are highly crystalline and rod-shaped, with diameters usually less than 10nanometers and lengths 500between tens of nanometers and nanometers. Cellulose nanofibrils are prepared by mechanical methods, with diameters of 5~ 60nanometers and lengths up to several microns. The two together constitute the core product system of nanocellulose due to their unique structural characteristics [1]。

2. Core Features: Combining environmental protection and high performance

The core reason why nanocellulose has become a popular new material is that it has both natural environmental protection properties and excellent performance beyond traditional materials. It perfectly fits the current industrial trends of ' sustainable development ' and ' carbon neutrality ' [5] . The main characteristics can be summarized as follows:

• Excellent mechanical properties : Its tensile strength can reach 7~8 GPa , far exceeding that of steel, its elastic modulus is about 100~140 GPa , its mass is only 1/5 of steel , but its strength is 5more than twice that of steel, which is equivalent to carbon fiber. Even at extremely low filling amounts, it can significantly improve the mechanical properties of the matrix material [5][6]。

• Green, environmentally friendly and renewable : The raw materials are derived from natural plant fibers such as wood, cotton, agricultural waste, etc., which are widely sourced and renewable. The preparation process is green and environmentally friendly, does not rely on petroleum resources, and has good biodegradability. It can be naturally degraded after being discarded and will not cause pollution to the environment [5][6]。

• Excellent functional properties : It has a large specific surface area, high crystallinity, high hydrophilicity and high transparency, and the light transmittance can exceed 90% ; it also has good chemical stability and biocompatibility, and the abundant hydroxyl groups in the molecule can also be used for various chemical modifications, giving it new functions such as hydrophobicity and electrical conductivity [1][5]。

• Good processing adaptability : After appropriate modification, a stable colloidal dispersion system can be formed in the aqueous phase, with excellent rheological characteristics and film-forming properties. It can be used in combination with a variety of polymers, metal oxides, etc., adapting to existing industrial production processes, and lowering the application threshold for enterprises [5]。

3. Diversified applications: empowering green upgrades in multiple industries

With its unique performance advantages, nanocellulose is gradually penetrating into many industrial fields, from ' invisible armor ' to ensure safety to ' nano barrier ' to protect freshness , from ' functional additives ' to improve quality to ' core materials ' to promote innovation . Its application scenarios are constantly expanding, becoming an important support for industrial upgrading [2]。

(1) Lithium battery new energy field: solving safety and performance problems

In the lithium battery industry, nanocellulose provides a new solution to solve the with cellulose nanowhiskers ( ' stuck ' problem of battery safety. The coating material CNC ) as the core can build a dense ' three-dimensional nano-armor ' on the surface of the separator , increase the heat-resistant temperature of the separator to above 180°C , and significantly improve the infiltration speed of the electrolyte [2] . At present, this technology has been widely used in consumer battery fields such as mobile phone power banks, tablet computers, and two-wheeled electric vehicles. The annual coating area exceeds 20100 million square meters. Some leading domestic companies have achieved stable supply of 10,000 tons, helping leading customers to pass 20263C certification under the new regulations [2]。

(2) Food packaging field: opening a new era of high-barrier freshness preservation

Driven by the dual drive of the ' plastic restriction order ' upgrade and consumption upgrade, the food packaging industry has an increasingly urgent need for high-performance environmentally friendly materials. The nanocellulose coating can form a dense ' nano-maze ' barrier on the surface of the packaging film, reducing the oxygen transmission rate ( OTR ) by more than 90% . The OTR of some products can be as low as 0.4 cm³/m²·d·0.1MPa . It has outstanding performance in the field of high-value food preservation such as nuts, coffee, and cold meat [2] . Compared with traditional materials, its ' smart barrier ' properties based on physical structure have the advantages of lightweight, high strength and full-chain greenness. It is also suitable for existing gravure coating production lines, significantly reducing the process conversion costs of packaging companies [2]。

(3) Papermaking field: improve quality and efficiency, break through industry bottlenecks

Nanocellulose has excellent compatibility with papermaking raw materials. As a dry strength agent added to the pulp, it can increase the tensile index of the paper by more than 30% , and at the same time improve the smoothness and powder loss of the paper [2] . Domestic scientific research institutions have broken through the bottleneck of difficult dispersion and high cost of nanocellulose in papermaking applications, and have achieved batch application in multiple paper types such as offset paper, white board paper, photovoltaic lining paper, and household paper [6] . For example, in the production of whiteboard paper, adding 1kg of nanocellulose products per ton of paper can increase the folding resistance of the paper by 38% and the cohesion of the bottom layer by 58% ; in household paper, adding nanocellulose can save 10% of bleached softwood pulp and 3kg of wet strength agent, and at the same time increase the dry strength by about 30% , achieving the dual goals of reducing costs and increasing efficiency [6]。

(4) Other frontier fields: Innovation potential continues to be released

In addition to the above fields, the application landscape of nanocellulose is still expanding: in the field of cosmetics, its three-dimensional nano-network structure can carry 200water twice its own weight, becoming an ideal moisturizing matrix for high-end facial masks [2] ; in the field of biomedicine, its good biocompatibility and degradability make it show great potential in drug sustained-release carriers, tissue engineering scaffolds, etc. [1][5] ; In the field of composite materials, as a green reinforcing phase, it can significantly improve the mechanical properties of plastics, rubber and other base materials, assisting the development of lightweight automobiles [2] ; In the field of environmental engineering, it can be used for sewage treatment, soil remediation, etc., providing new paths for ecological protection [1]。

4. Industry trends: from laboratory to large-scale, broad prospects

As the production process continues to mature and costs continue to decrease, nanocellulose is transforming from a ' rare species ' in the laboratory to a ' routine option ' in the industry [2] . According to market research institutions, the global nanocellulose market 2032is expected to reach 8.77100 million US dollars by the year, with a compound annual growth rate of 15.3% , and the United States Department of Agriculture and Forestry Service ( USDA ) even predicts that the global nanocellulose market potential can reach 350010,000 tons [2][6]。

At present, the country has gradually formed an industrial structure covering a full product matrix such as CNC, 、CNF, 、MFC , etc. Some companies have built the country's first 10,000-ton or high-concentration green preparation pilot demonstration line. The level of equipment localization has been continuously improved, and it has been able to serve many 1000customers around the world [2][6] . The industry is upgrading from ' material supply ' to ' solutions ' , and through in-depth collaboration with downstream companies, it is promoting the large-scale implementation of nanocellulose in more scenarios [2]。

In the strategic context of the ' 15th Five-Year Plan ' to promote high-quality development and accelerate green and low-carbon transformation, nanocellulose, as a ' new generation of green nanomaterials ' , its industrial development is in line with the national strategic orientation, and it also provides important opportunities for enterprises to deploy in emerging fields and achieve transformation and upgrading [3] . In the future, with the continuous breakthroughs in green preparation technology and the continuous expansion of application scenarios, nanocellulose will further reshape the industrial landscape and inject lasting power into global green development.

V. Conclusion

Extracted from natural plant fibers and reborn at the nanoscale, the rise of nanocellulose is not only a major breakthrough in materials science, but also a vivid practice of the concept of green development. With its unique advantages of ' originating from nature and returning to nature ' , it breaks the performance boundaries of traditional materials and empowers high-quality development in many industries such as lithium batteries, packaging, and papermaking.

We have always focused on technological innovation and industrial applications in the field of nanocellulose, deeply engaged in the research and development of green materials, helping enterprises reduce costs, increase efficiency, and achieve green transformation. We work with partners to jointly tap the unlimited potential of nanocellulose, build a green future, and share new opportunities for industrial development.