Chemical-Physical Treatment for Production of Cellulose Nanofiber from Kenaf Bast Fiber

This paper presents the isolation of kenaf bast fiber to produce cellulose nanofiber (CNF) using chemical-physical treatment (e.g. delignification, bleaching and ultrasonication). Raw bast fiber was bleached and then subjected to high-intensity ultrasonication at four different output powers (100 W, 200 W, 400 W and 700 W). SEM and TEM analysis of treated bast fiber revealed that the morphological structure of CNF with diameter distribution in the range less than 100 nm (100 W) to 10 nm (700 W). Hemicellulose and lignin content were successfully reduced by chemical treatments, as there was increment of the cellulose content in the fiber more than 90% recorded. Higher ultrasonication output power attributes to the decreasing diameter size of CNF. This finding reflected that smaller CNF fibrils provide larger surface area per volume ratio. Larger stretching vibration of - OH group is detected as the higher composition of cellulose in CNF. CNF produced also had higher thermal stability than raw bast fiber after undergoes the chemical-physical treatment. Therefore, chemical-physical treatment did not only to attribute the success of deposition of lignin and hemicellulose, but also to increase the nano-sized fiber distribution in CNF suspension.