Physicochemical Characterization of Acid-Treated Nanocrystal Cellulose and Amorphous Cellulose from Bamboo Sawdust

The major by-product of bambooworking (i.e. making items from bamboo) is bamboo sawdust, which is a waste product from bambooworking operations and can cause human health hazards. Specifically, this experimental research investigates the effects of acid treatment methods on the physicochemical characteristics of nanocellulose fibers from bamboo sawdust. The experimental acid treatment methods are sulfuric acid hydrolysis for bamboo fiber nanocrystal cellulose (BBF-NCC) and sulfuric acid dissolution for bamboo fiber amorphous cellulose (BBF-AC). The physicochemical properties of nanocellulose from bamboo sawdust include the crystalline structure, morphology, and colloidal stability. The experimental results indicate that BBF-NCC possesses a higher crystallinity index (89.5%), in comparison with 35.4% for BBF-AC. The BBF-NCC is of rod shape with 10 nm in diameter and 50-100 nm in length, while BBF-AC coalesces into clusters of varying sizes. In addition, BBF-NCC possesses higher colloidal stability than BBF-AC, as indicated by a zeta potential of -30.93 mV for BBF-NCC, compared with -19.73 mV for BBF-AC. Essentially, this research is the first to experimentally convert bamboo sawdust into cellulose nanofibers as an eco-friendly and economically viable solution to the waste problem from the bamboomaking industry. Moreover, BBF-NCC and BBF-AC could potentially be adopted as a reinforcing agent in biocomposites or as a carrying agent in multiple applications.