Characterisation of structural and physical properties of cellulose nanofibers from Pennisetum purpureum

Recently, cellulose nanofiber (CNF) and its applications gain immense attraction in both research and industrial areas due to its attractive properties such as excellent mechanical properties, high surface area, rich hydroxyl groups for modification, and natural properties with 100% environmental friendliness. Pennisetum purpureum, also known as Napier grass fibre is a newly-identify plant which is highly sustainable throughout Malaysia. In this study, the typical extraction of cellulose nanofiber from Pennisetum purpureum method is summarised, in which the cellulose nanofiber extraction concerning alkali treatment and planetary ball milling is mainly introduced. Cellulose nanofiber from Pennisetum purpureum also has been extracted using different concentration acid hydrolysis, such as 20% and 30% to observe the effect towards the fibre bonding. The morphology, chemical structure and crystallinity of the fibre were obtained using scanning electron microscopy SEM, Fourier transform infrared spectroscopy FTIR, and X-ray diffraction XRD. SEM clarifies that the increment of acid hydrolysis lowers the fibre-fibre bonding upon freeze-drying of the cellulose nanofiber suspensions. The result of XRD and SEM shows that 30% of acid hydrolysis gives higher crystallinity and chemical effect towards the structure of cellulose nanofibers. (paper)