Physicochemical properties and thermal stability of microcrystalline cellulose isolated from oil palm biomass fibers using totally chlorine-free delignification approach

This study investigated the production of microcrystalline cellulose (MCC) from oil palm biomass, namely empty fruit bunches (EFB), oil palm fronds (OPF), and oil palm trunks (OPT), using a totally chlorine-free (TCF) delignification process followed by sulfuric acid hydrolysis (0.5–2.5%). The influence of biomass source and hydrolysis conditions on the physicochemical properties of MCC was evaluated using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and water dispersion analysis. OPF exhibited the highest cellulose content (35.21 wt%), while OPT achieved the highest MCC conversion yield (83.29 wt%) at 0.5% sulfuric acid concentration. FTIR analysis confirmed the successful removal of non-cellulosic components and the formation of cellulose-rich MCC. The highest crystallinity index (69.1%) was obtained for OPT-derived MCC prepared with 2.0% sulfuric acid, indicating effective removal of amorphous regions during hydrolysis. TGA revealed good thermal stability for all MCC samples, with the highest degradation temperature (Tmax = 382.0 °C) observed for EFB-derived MCC. SEM analysis showed irregular rod-like MCC particles with diameters below 30 µm. The water dispersion test showed that MCC had better initial dispersion in water than extracted cellulose, with slight sedimentation observed after prolonged storage. Overall, the results demonstrated that both biomass type and acid concentration significantly influenced the structural, thermal, morphological, and dispersion properties of MCC. These findings demonstrate the potential of oil palm biomass as a sustainable feedstock for the production of high-quality MCC for pharmaceutical, food, and chemical applications.