AbstractThis study presents the utilization of oil palm ash (OPA), a siliceous material from the fiber of oil palm biomass, as a nanofiller for the development of polymer nanocomposites. Polypropylene-based polymer nano-composites reinforced with OPA along with a compatibilizer were prepared by a melt-mixing technique, using a double screw extruder. Variations in the mechanical, morphological, and thermal properties with the filler and compatibilizer loading were studied. The best dispersion occurred in the polymer nano-composites for which the interactions between the polymer matrix and nanosized OPA appeared to be the highest. The particle size and the dispersion of the oil palm ash within the matrix were determined by transmission electron microscopy. The as-synthesized composite materials were typically characterized by tensile and impact test methods. The morphology of the composite materials was studied by scanning electron microscopy. The thermal properties determined by thermogravimetric analysis (TGA) showed enhanced thermal stability of a series of composite materials. Also, melting studies were carried out by differential scanning calorimetry.