Green Synthesis of NCC From Oil Palm Empty Fruit Bunch (OPEFB) via Low‐Acid Hydrolysis With Analysis of Conductivity

ABSTRACT Nanocrystalline cellulose (NCC) was successfully synthesized from oil palm empty fruit bunches (OPEFB) via a green approach involving alkaline treatment, bleaching, low‐concentration sulfuric acid hydrolysis (30% and 40%), and eco‐drying. This study investigated the effect of sulfuric acid concentration on the morphology, crystalline structure, functional groups, particle size distribution, surface charge, colloidal stability, and electrical conductivity of NCC. Morphological analysis revealed that NCC obtained using 30% H 2 SO 4 exhibited agglomerated and irregular structures, indicating incomplete hydrolysis, whereas 40% H 2 SO 4 produced more defined rod‐like nanocrystals with improved dispersion. X‐ray diffraction confirmed the preservation of cellulose I structure, with crystallinity indices of approximately 54% and 55% for 30% and 40% H 2 SO 4 , respectively. FTIR analysis verified that the fundamental chemical structure of cellulose remained intact after hydrolysis. Particle size analysis showed that 30% H 2 SO 4 resulted in a broader distribution with larger particles, while 40% H 2 SO 4 yielded a narrower and more uniform size distribution around 400–500 nm. Zeta potential measurements indicated high negative surface charges, with the 30% H 2 SO 4 sample showing slightly higher magnitude (–45 to –50 mV) compared to the 40% sample (–40 to –45 mV), suggesting better colloidal stability at lower acid concentration. Electrical conductivity exhibited frequency‐ and thickness‐dependent behavior, with stable conductivity at high frequencies. These results demonstrate that low‐acid hydrolysis produces NCC with promising structural and functional properties for sustainable optoelectronic and sensing applications.