Effect of <scp>NaOH</scp> Treatment and Solvent Extraction on the Chemical Composition and Morphology of False Banana ( <scp> <i>Ensete ventricosum</i> </scp> ) Fibers

ABSTRACT Natural fibers have attracted increasing attention as sustainable alternatives to synthetic reinforcements due to their biodegradability, renewability, and low environmental impact. False banana ( Ensete ventricosum ) fibers, however, contain significant amounts of noncellulosic components such as hemicellulose, lignin, and extractives, which can limit their interfacial performance in composite materials. This study investigates the effects of sodium hydroxide (NaOH) pretreatment at concentrations of 2%–8% combined with Soxhlet benzene–ethanol (2:1 v/v) extraction on the chemical composition and surface morphology of these fibers. Chemical analysis revealed that NaOH treatment substantially reduced extractives from 1.28% to 0.35% and hemicellulose from 16.21% to 9.44%, while lignin content decreased from 19.65% to 15.50%, indicating partial delignification. Thus, the calculated cellulose content increased from 62.87% in untreated fibers to 74.71% after 8% NaOH treatment, reflecting the progressive removal of noncellulosic components rather than an absolute increase in cellulose. Scanning electron microscopy revealed progressive surface cleaning, increased fibrillation, and enhanced surface roughness with increasing NaOH concentration. Fibers treated with 4%–6% NaOH exhibited the most favorable balance between chemical purification and structural integrity, whereas treatment with 8% NaOH resulted in surface microcracks and partial structural degradation due to excessive alkali attack. These findings reveal that the combined NaOH/Soxhlet pretreatment effectively improves both the chemical purity and surface morphology of E. ventricosum fibers, thereby improving their potential as sustainable reinforcement materials for biocomposite applications.