Sources, Chemical Functionalization, and Commercial Applications of Nanocellulose and Nanocellulose-Based Composites: A Review

Abstract

Nanocellulose is the most abundant material extracted from plants, animals, and bacteria. Nanocellulose is a cellulosic material with nano-scale dimensions and exists in the form of cellulose nanocrystals (CNC), bacterial nanocellulose (BNC), and nano-fibrillated cellulose (NFC). Owing to its high surface area, non-toxic nature, good mechanical properties, low thermal expansion, and high biodegradability, it is obtaining high attraction in the fields of electronics, paper making, packaging, and filtration, as well as the biomedical industry. To obtain the full potential of nanocellulose, it is chemically modified to alter the surface, resulting in improved properties. This review covers the nanocellulose background, their extraction methods, and possible chemical treatments that can enhance the properties of nanocellulose and its composites, as well as their applications in various fields.

TEMPO-Oxidized Cellulose Nanofibril Films Incorporating Graphene Oxide Nanofillers

“…The C6 primary hydroxyl groups were converted to carboxylate groups via NaClO/NaBr/TEMPO oxidation at three different TEMPO and NaBr catalyst levels [ 5 ]. This was measured via conductometric titration based on the consumed amounts of NaOH.…”

“…A FE-SEM (field emission scanning electron microscopy) was used to investigate the uniformity of fibril layers and any morphological changes upon the different degrees of oxidation and GO loadings. According to several studies, it has been found that surface modification via TEMPO does not influence the morphology of any TOCN samples [ 5 ]. Even with the introduction of the high amount of carboxylate groups, the original cellulose structure tends to be sustained since the oxidation preferably occurs on the surfaces and amorphous disordered regions [ 25 ].…”

“…Nanofibrillated cellulose (NFC) is a good polymer matrix candidate with high stiffness and elastic moduli, making it suitable for the fabrication of nanocomposites [ 3 , 4 ]. Cellulose fibrils, ranging from 10 to 100 nm in width, are generally produced via two main processes: mechanical refining and high-pressure homogenization of natural pulps [ 5 , 6 ]. In spite of the high energy input by intense mechanical treatment, the complete isolation of cellulose fibril bundles is not attainable owing to the abundant hydrogen bonds tightly linking the fibrils [ 6 ].…”

Cellulose-based green triboelectric nanogenerators: materials, form designs, and applications

“…To overcome this, various nanocellulose and cellulose derivatives have been developed by using a variety of methods such as mechanical, chemical, and biological methods. For example, Tahir et al 81 summarized the types, extraction methods, and possible chemical treatments that can enhance the properties of nanocellulose and its composites. Jiang and Ngai 82 summarized the structural and biochemical properties of cellulose and its derivatives.…”

A Review on Barrier Properties of Cellulose/Clay Nanocomposite Polymers for Packaging Applications

“…Compared with the mechanical method, the chemical method is better because it produces CNCs with improved crystallinity and reduces energy consumption [ 54 ]. However, acid hydrolysis is the most widely explored technique [ 55 , 56 ].…”