Nanocellulose is a lightweight, biodegradable nanomaterial derived from cellulose, the most abundant natural polymer on Earth. Owing to its exceptional properties, such as high tensile strength, tunable surface chemistry, and excellent barrier characteristics, 

it holds significant promise as a sustainable alternative in various industries, including packaging, electronics, and biomedical engineering. This paper explores the characteristics, history, properties, and wide-ranging applications of nanocellulose, emphasizing its role in advancing environmentally friendly technologies. Discover how Nanografi's advanced nanocellulose technology is utilized in various fields.

Introduction

In recent years, there has been significant interest in utilizing biomass as a source of renewable energy and materials. Among the developments in this area, nanocellulose has emerged as a promising nanostructured material, largely due to advancements in nanotechnology. Derived from cellulose, the most abundant natural polymer, nanocellulose offers exceptional properties that make it suitable for a wide range of industrial applications, including packaging and electronics. Moreover, it is carbon-neutral, biodegradable, sustainable, non-toxic, and environmentally friendly, allowing for large-scale industrial use without detrimental environmental impacts.

Characteristics of Nanocellulose

Nanocellulose consists of cellulose particles or fibrils with widths or diameters less than 100 nanometers. It is a lightweight yet robust substance extracted from plant matter. Notably, nanocellulose exhibits pseudoplastic behavior, meaning it has properties of fluids or gels that are thick under normal conditions but become less viscous when shear forces are applied. The lateral dimensions of nanocellulose range from 5 to 20 nanometers, while the longitudinal dimensions vary from tens of nanometers to several micrometers.

Cellulose serves as the primary source for producing nanocellulose or cellulose suspensions. Lignocellulosic materials, plants containing cellulose, hemicellulose, and lignin, are processed to extract cellulose with desirable characteristics. Lignin acts as a binding component, providing stiffness, strength, and protection to the cell wall. The strong hydrogen bonds between adjacent glucose units in cellulose result in a compact structure with a tightly packed network of fibers, conferring hardness, toughness, strength, and antibacterial properties.

These inherent properties make cellulose an ideal material for various applications. Nanocellulose derived from natural cellulose is biodegradable and lightweight, with a density of approximately 1.6 grams per cubic centimeter and a high tensile strength of about 10 gigapascals, comparable to cast iron. Additionally, the reactive hydroxyl groups on the cellulose surface allow for functionalization, enhancing its applicability in numerous fields.

There are three main types of nanocellulose materials:

• Nanofibrillated Cellulose (NFC)
• Cellulose Nanocrystals (CNC)
• Bacterial Nanocellulose (BNC)

These materials possess distinctive properties such as tunable surface chemistry, high crystallinity, superior mechanical strength, barrier properties, high aspect ratios, biodegradability, and non-toxicity. Owing to these attributes and their status as renewable green substances, nanocellulose materials have become highly desirable for applications in food packaging, coatings, composite fillers, and a myriad of other industrial uses that have the potential to significantly influence and transform commercial sectors.

History

Nanotechnology has garnered substantial interest across various industries due to the numerous possibilities it offers. Nanocellulose is among the recent advancements in this field. Through chemical modifications or mechanical treatments, cellulose can be transformed into nanofibrils (CNFs) or cellulose nanocrystals (CNCs), which exhibit significantly different properties compared to traditional materials like carbon fibers, Kevlar, and stainless steel.

Although extensive research is ongoing, nanocellulose is not yet widely used commercially. The first production unit of CNC was established in 2012 by CelluForce in Canada, producing about one ton of CNC per day. Since then, several other pilot plants have been developed. The first dedicated pilot plant was established at Innventia in Sweden in 2011, followed by a facility in Madison, USA, in 2012. A unique pilot plant was also established in 2016 in Örnsköldsvik, Sweden.

These pilot plants aim to facilitate the commercialization of nanocellulose by providing researchers and early adopters with access to this material for research and development. Since its introduction in the 1980s, nanocellulose has been the subject of extensive research. The drive toward a more sustainable economy has intensified interest in nanocellulose, focusing on its development and application in various products.

Properties of Nanocellulose

Nanocellulose exhibits remarkable physical and chemical properties. It is lightweight, electrically conductive, non-toxic, and can be produced cost-effectively on a large scale. Some of its notable properties include:

Dimensions and Crystallinity: Determining the exact dimensions and crystallinity of nanocellulose is challenging due to fiber entanglement and difficulties in locating individual fiber ends. Nanocellulose suspensions are heterogeneous, containing various structural components besides nanofibrils and bundles. Studies indicate that the lateral dimensions range from 5 to 20 nanometers, while the longitudinal dimensions vary from tens of nanometers to several micrometers. The cellulose retains its crystalline structure, with an estimated crystallinity degree of around 63%.

Mechanical Properties: Nanocellulose suspensions exhibit remarkable stiffness, ranging from 140 to 220 gigapascals, comparable to Kevlar and exceeding that of glass, both used as plastic reinforcements. The high stiffness and strength of nanocellulose also surpass those of stainless steel.

Viscosity: Rheological studies have shown that at concentrations between 0.125% and 5.9%, the storage and loss moduli of nanocellulose are independent of angular frequency. The material exhibits shear-thinning behavior, where viscosity decreases under shear stress, making it highly useful for coating applications.

Bulk Foam and Aerogel Characteristics: Nanocellulose can strengthen starch foams through its nanofibrils. Foams and aerogels derived from nanocellulose serve as porous templates and can be compressed to produce strong magnetic nanopapers, which have potential applications as functional membranes.

Barrier Properties: Crystalline regions in semicrystalline polymers are impermeable to gases. Nanofibers can form a highly dense network held together by strong interfibrillar bonding. These characteristics suggest that nanocellulose may act as an efficient barrier material.

Other Properties: Nanocellulose exhibits interesting optical and rheological properties and allows for easy surface modifications, expanding its range of applications.

Applications of Nanocellulose – Cellulose Suspensions

Nanocellulose can be used to fabricate bionanocomposites such as starch plastics, polylactides, and bacterial polyesters. There are two main types of cellulose-based biocomposites:

• Structural Biocomposites
• Nonstructural Biocomposites

Both types have applications in industries such as paper and packaging, construction materials (e.g., tiles, ceilings, doors, furniture), as well as in the automotive, pharmaceutical, electronics, and cosmetic sectors.

Composites and Fillers: Nanocellulose shows potential as a reinforcing agent in the processing of bionanocomposites, including foams, coatings, and films.

Paper and Packaging: In these industries, nanocellulose has replaced synthetic polymers derived from petrochemicals. Its nanoscale dimensions and excellent water and gas barrier properties are particularly advantageous. Being renewable, cost-effective, and non-toxic, it is suitable for food packaging. Studies have emphasized its effectiveness as a reinforcing agent in nanoclay and polylactic acid matrices, resulting in products with enhanced oxygen and water barrier properties.

Electronics Industry: The enhanced conductivity and flexibility of nanocellulose make it suitable for electronic applications. Polyaniline-nanocellulose composites can be used in paper-based sensors, conductive adhesives, electronic devices, and flexible electrodes. It is also utilized in paper-based energy storage devices with high charge and discharge rates, excellent cycling performance, and high capacitance. In flexible organic electronics, nanocellulose is used in displays, windows, and sensors designed to detect structural stress in infrastructures like bridges.

Biomedical Applications: Due to its high surface area-to-volume ratio, modifiable surface chemistry, and strength, nanocellulose is suitable for biomedical applications. Nanocellulose-reinforced hydrogel composites enhance the mechanical properties of polymeric gels and hydrogels, offering improved pH sensitivity and mechanical strength. This makes them valuable for pharmaceutical and gene delivery applications. Recent research focuses on using nanocellulose as scaffolds in tissue engineering.

Food Industry: Nanocellulose serves as a low-calorie replacement for carbohydrate additives previously used as suspension stabilizers, thickeners, and flavor carriers. It is employed in products like puddings, wafers, soups, and chips.

Hygiene and Absorbent Applications: It is extensively used as a superabsorbent material in wound dressings, sanitary napkins, tampons, and kitchen towels, often in the form of freeze-dried nanocellulose aerogels.

Medical and Pharmaceutical Applications:

• Used as an excipient in pharmaceutical formulations.
• Incorporated into tablets for treating intestinal disorders.
• Applied in leukocyte-free blood transfusions.
• Utilized in cryostructured gels with improved elasticity for biomedical applications.

Cosmetics: In the cosmetics industry, nanocellulose is used as a coating agent for eyelashes, eyebrows, hair, and nails.

Other Applications:

• Ultra-white coatings as a highly scattering material.
• Lightweight body armor and bulletproof glass.
• Corrosion inhibitors.
• High-flux loudspeaker membranes.
• Additives in tobacco filters.

Conclusion

Nanocellulose has emerged as a material of significant importance due to its lightweight nature, high strength, and other remarkable characteristics. Researchers and industry professionals are actively exploring different manufacturing processes and applications of nanocellulose suspensions. With ongoing advancements in nanotechnology, it is anticipated that nanocellulose will become widely used across various industries. One of its greatest advantages is its biodegradability and the abundance of its primary source—cellulose, the most plentiful natural polymer. Consequently, nanocellulose is cost-effective and environmentally friendly, replacing petrochemical-based materials traditionally used in industry. Although its commercial use is currently in the early stages, nanocellulose possesses the potential and necessary characteristics to be fully exploited in the future for the benefit of society.

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