Earticle

The environmental impact of petroleum-based plastics packaging continues to grow, increasing attention has been directed toward the development of sustainable materials derived from renewable biomass. Cellulose-based biomass from agricultural residues and food processing by-products has emerged as a promising alternative due to its abundance, renewability, and biodegradability. To enhance the processability and applicability of cellulose derived from such sources, recent studies have focused on chemical modification techniques such as 2,2,6,6-tetramethylpiperidinyloxy (TEMPO)- mediated oxidation, as well as the use of advanced solvent systems including ionic liquids for the production of regenerated cellulose (RC) films. This review explores the fundamental principles and mechanisms of TEMPO-mediated oxidation and highlights the characteristics and potential applications of TEMPO-oxidized cellulose nanofibers (TOCNFs) derived from various biomass sources. In addition, it discusses the fabrication and performance of TOCNF composite films, major cellulose solvent systems and their dissolution mechanisms, and the properties and applicability of RC films.

In this study, cellulose nanofibrils (CNF) were modified through carboxymethylation or TEMPO-mediated oxidation and their effects on ionicity and characteristics of sheet, film, and foam were investigated. Carboxymethylation was carried out on pulp fibers as a pre-treatment before preparation of CNF. The gel-like and translucent CNF hydrogel was obtained by grinding of carboxymethylated cellulose fibers. Carboxymethylated CNF film and freeze dried sheet showed higher transparency than that of untreated CNF. The CNF sheet with high strength and the CNF foam without large ice crystals were obtained by using the carboxymethylated CNF. TEMPO-mediated oxidation was carried out as a post-treatment of CNF. The zeta potential and charge demand of TEMPO-oxidized CNF were increased with an increase in oxidation time and addition amount of NaClO. The density of sheet made of TEMPO oxidized CNF was increased with the amount of oxidizing agent. The TEMPO oxidized cellulose nanofiber (TOCN) which was obtained from supernatant after centrifugation could be converted to transparent film.