Rice Husk Ash as Fillers in Polypropylene: A Preliminary Study

Burnt rice husk ash yields two types of fillers namely black rice husk ash (BRHA) and white rice husk ash (WRHA). These ashes were incorporated into polypropylene using a Brabender thermoplastics mixer. Torques at various filler loadings were investigated. For both types of ashes, the mixing torques increase with filler contents; the increase being more prominent in the BRHA. Polypropylene composites of different filler loadings were compounded using a twin screw extruder and test specimens were injection molded. Thermogravimetry analysis showed a good agreement between analyzed and actual filler content The composites were found to have a good filler distribution by the same technique. Flexural modulus and density showed an increase whereas tensile strength, elongation at break and impact strength decreased with increasing filler content. Poor adhesion between polymer and filler was indicated by SEM studies.