Characteristics of TEMPO-Oxidized Cellulose Nanofibers from Oil Palm Empty Fruit Bunches Produced by Different Amounts of Oxidant

Abstract

The use of oil palm waste as a source of raw materials for nanocellulose production is a promising approach for turning agricultural waste into valuable products. This study aimed to characterize cellulose nanofibers (CNFs) derived from oil palm empty fruit bunches (OPEFB) produced by 2, 2, 6, 6-tetramethylpiperidine 1-oxyl (TEMPO)/NaBr/NaClO. TEMPO-mediated oxidation was carried out at pH 10 by applying different amounts of oxidant: 10, 15 and 20 mmol/g-cellulose at room temperature for 2 h, where the resultant CNFs were denoted as T-10, T-15 and T-20, respectively. Characterization results revealed that the carbon content of each CNF decreased as compared to the starting pulp, from 40% to ca. 37%. Microscopic analysis showed that the aspect ratios of obtained CNFs remained almost unchanged by increasing the amounts of oxidant, which were ca. 40. The crystallinity indices (CrIs) ranged from 34 to 55%. The carboxy contents of CNFs increased by adding higher amounts of oxidant, but the thermal resistance properties were slightly decreased. High-performance nanomaterials such as TEMPO-oxidized CNFs were successfully prepared to show good characteristics, from low-quality biomass waste such as OPEFB.