The Effect of Mechano-enzymatic Treatment on the Characteristics of Cellulose Nanofiber Obtained from Kenaf (Hibiscus cannabinus L.) Bark

Cellulose nanofiber (CNF) was successfully isolated from kenaf bark by microfluidization at 20,000 psi for 40 passes. The combination of hydrothermal process and xylanase treatment prior to CNF isolation led to effective cellulose purification. The fiber used for enzymatic pretreatment for CNF isolation had an 85.9% whiteness index and 85.1% cellulose content. The crystallinity of the cellulose extracted from the kenaf bark continued to increase with successive treatments, as indicated by X-ray diffraction analysis. In addition, the enzyme-treated fiber showed increased thermal stability, as shown by thermogravimetric analysis. After CNF isolation, morphological characterization of the CNF was performed via field emission-scanning electron microscopy and transmission electron microscopy. The CNF had an average diameter that ranged from 5 to 10 nm and no undesired elemental contamination, as evidenced by energy dispersive X-ray spectroscopy. The mechano-enzymatic treatments used in this work to obtain CNF were judged to be a promising technique for the fabrication of biomedical and other high-value materials.