PEER-REVIEWED ARTICLE bioresources.com Bhat et al. “Oil palm ash based PP composites,” BioResources 6(2), 1288-1297. 1288 EXPLORING “NANO FILLER” BASED ON OIL PALM ASH IN POLYPROPYLENE COMPOSITES A. H. Bhat, a and H. P. S. Abdul Khalil a, * This 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. Keywords: Oil palm ash; Polypropylene; Polymer nanocomposites; Transmission electron microscopy Contact information: School of Industrial Technology, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia; * Corresponding author: akhalilhps@gmail.com INTRODUCTION Soaring prices are a reminder of the essential role that affordable products play in sustainable economic growth and higher human development. Utilization of bioresource materials, especially from clean indigenous resources, has become more pressing than ever. Oil Palm Ash (OPA) is an abundant agricultural solid material in Malaysia and Thailand. In Malaysia alone, the potential oil palm ash production has been estimated at four million tonnes/year, a quantity that has prompted a great deal of criticism and complaints, mainly attributed to its persistent, carcinogenic, and bio-accumulative effects (Subramaniam 2008; Foo and Hameed 2009). Increasingly, with the price of the ash disposal cost (either in landfills or ash ponds) hitting as high as $5/tonnes in developing countries and $50/tonnes in developed countries, the urgency of transforming the bioresource residue into a more valuable end products has been promulgated (Foo and Hameed 2009). The ash is produced after the combustion of oil palm fiber and shell as boiler fuel to produce steam for palm oil mill consumption. Although there are some studies on the utilization of OPA such as a cement replacement material, as an adsorbent for the removal of zinc from aqueous solution (Chu and Hasyim 2002), and for flue gas desulphurization (Zainudin et al. 2005), most of the ash is still disposed of in landfills, an outcome that requires a lot of land area.