Mechanical Properties of Isotactic Polypropylene/Wood Flour Composites

Tensile and impact properties of wood flour filled isotactic polypropylene composites are studied at 0–70 wt% filler levels. Tensile modulus showed an increase whereas tensile strength and breaking elongation decreased with increasing filler content. Restriction in molecular mobility or deformation of polypropylene by wood flour particles accounted for the modulus increase and elongation decrease while increased amorphization and introduction of stress concentration points explained the decrease in tensile strength. Izod impact strength increased up to a critical filler concentration beyond which the value registered a slow decrease. Surface treatment of wood flour with a titanate coupling agent LICA 38 modifies further the mechanical properties. Better dispersion of filler particles upon surface treatment was indicated by SEM studies.