Preparation and characterization of cellulose nanocrystals from spent edible fungus substrate

Periodate oxidation-mediated nanocelluloses: Preparation, functionalization, structural design, and applications

In recent years, the remarkable progress in nanotechnology has ignited considerable interest in investigating nanocelluloses, an environmentally friendly and sustainable nanomaterial derived from cellulosic feedstocks. Current research primarily focuses on the preparation and applications of nanocelluloses. However, to enhance the efficiency of nanofibrillation, reduce energy consumption, and expand nanocellulose applications, chemical pre-treatments of cellulose fibers have attracted substantial interest and extensive exploration. Various chemical pre-treatment methods yield nanocelluloses with diverse functional groups. Among these methods, periodate oxidation has garnered significant attention recently, due to the formation of dialdehyde cellulose derived nanocellulose, which exhibits great promise for further modification with various functional groups. This review seeks to provide a comprehensive and in-depth examination of periodate oxidation-mediated nanocelluloses (PONCs), including their preparation, functionalization, hierarchical structural design, and applications. We believe that PONCs stand as highly promising candidates for the development of novel nano-cellulosic materials.

Isolation and characterization of cellulose nanocrystals from Chinese medicine residues

Nanocellulose has become a vital material with excellent and crucial properties in the field of nanotechnology and advanced materials science. Plant-based traditional Chinese medicines are mostly plant rhizomes, which contain a large amount of cellulose, hemicellulose, and lignin. In this study, carboxylated cellulose nanocrystals (CNCs) were prepared from traditional Chinese medicine residues (CMR) by sequential periodate-chlorite oxidation without mechanical treatment. The obtained nanocelluloses were analyzed by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and X-ray diffractometry (XRD); the carboxyl content and specific surface area were also measured, simultaneously. XRD results revealed that the crystallinity index decreased after sequential oxidation; however, the cellulose I structure was maintained. From the morphology analysis, the average length and width of CNCs were 139.3 and 10 nm, respectively. From the FTIR analysis, with the particle size decreasing, hydrogen bonds were broken and recombined. TGA results showed that the thermal property was decreased with a reduction of nanocellulose particle size and crystallinity index. This study is the first to refine utilization of traditional Chinese medicine residues as a potential source of cellulose, that is, to prepare nanocellulose efficiently with high carboxyl content which finds its application in nanomaterials.