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Cellulose is the main building block of trees and plants. It is considered as the most abundantly found natural linear biopolymer possessing exceptional mechanical properties. Nanocellulose from plants or bacteria has excellent physical, mechanical, and optical properties.
Crystalline nanocellulose has more promising characteristics than original cellulosic fibers. The cellulose fibers can be converted into cellulose nanofibers (CNF) or crystalline nanocellulose (CNC) after mechanical or chemical treatments.
As a novel sustainable nanomaterial, CNC has wide ranging applications, some of which are discussed below.
CNC is organized as a tightly packed array of needle-like crystals. These crystal structures are extremely tough and their strength is nearly eight times higher than stainless steel. Thus, this material is utilized for the production of body armor, e.g. Kevlar.
The rapidly evolving electronics industry and its ever-growing needs require constant innovation. In the recent past, the demand for sustainable energy devices such as lithium ion batteries, supercapacitors, and solar cells has increased rapidly.
Some of the important parts inside a battery are made up of stiff materials which cannot be molded. CNC combined with graphene material makes the production of a flexible battery possible in the electronic industry.
CNF can be used to filter and purify liquids such as saltwater to produce drinkable water, filtering out blood cells during transfusion, and filtering dangerous chemicals in cigarettes.
When CNC is mixed with the aerogel foam, a highly porous material with adsorbent characteristics is obtained which are used to make strong and light wound dressing gauzes and tampons.
Fuel Efficient Cars
When heavy parts of the car are replaced with light components reinforced with nanocellulose, the weight of the car decreases significantly and therefore the fuel consumption of the cars is greatly reduced.
Biodegradable Polyester Nanocomposites Prepared by in situ Polymerization
The addition of small amounts of CNC results in a slight decrease in viscosity, indicative of a reduction in the molecular weight of the polymer which is attributed to altered polymerization kinetics.
CNC is a very efficient nucleating agent for biodegradable aliphatic polyesters.
Biofuel can be produced from the microalgae present in waste-water with the help of CO2 switchable CNC modified with 1-(3-aminopropyl) imidazole (APIm).
Paper coated with CNC not only increases the surface gloss but also improves the mechanical and printable quality of the coated papers.
The addition of CNC into a pressure-sensitive adhesive results in a significant increase in the overlap shear properties of the adhesive while maintaining the peel adhesion.
A very small amount, i.e., 0.5-15 percent weight of CNC, relative to the weight of the adhesive (meth)acrylate copolymer, is required for the increase in shear properties with the acrylic pressure-sensitive adhesives.
CNC is known to be a stronger material than steel. The addition of CNC improves the formation of calcium-silicate-hydrate (CSH) gel in the cement matrix.
The formation of CSH gel in cement mortar enhances the strength of the cement composites by up to 42-45% compared to conventional cement mortar.
Plastics and Composites
CNC is applied in different concentrations to a wide range of polymer matrices in the production of rubbers, thermoplastics, thermosets, and biodegradable polymers amongst others.
The preparation of each type of polymer composite has unique challenges for obtaining the desired properties and good dispersions of nanocellulose in the polymer matrices.
Paints and Coatings
The addition of CNC to coatings not only increases mechanical properties but also increases color stability.
CNC in UV water-based coatings results in an approximately 30– 40% increase in wear resistance, i.e., against abrasions and scratches, without any loss of its visual appeal.
CNC is used in therapeutics. It can increase porosity, degradability, and drug release ability. It can also alter the properties of tissue scaffolds through its chemical properties and increase cell viability.
Other uses of CNC
CNC is used in optical sensors, the food industry, and the packaging industry.