LAUSR

Abstract In this study, carboxy-functionalized spherical cellulose nanoparticles have been produced from Alfa plant-derived cellulose microfibers (CMF) using ultrasonic-induced cellulose fragmentation process. CMF, with fiber diameter of 7.26 µm and crystallinity of 87%, were firstly produced from Alfa plant fibers and then subjected to surface carboxylation using TEMPO-mediated oxidation process. The as-resulted TEMPO-oxidized CMF (T-CMF), with an average diameter of 2.72 µm, a crystallinity of 89% and carboxyl groups content of 1032 mmol COO-/Kg cellulose , were then exposed to ultrasonication treatment for 45 min, resulting in the formation of cellulose nanospheres (CNS) with an average diameter of 33.96 ± 7.01 nm and a crystallinity of 76%. The carboxyl groups content on the surface of CNS was measured at 945 mmol COO-/Kg cellulose. This study demonstrated the importance of the ultrasonication process as a green method for producing CNS with interesting properties, which can be used in various potential functional applications.