The effects of calcium carbonate (CaCO3) content on the hardness, tensile and dynamic mechanical properties and impact strength of the filled polypropylene (PP) composites have been investigated in the present paper. The results show that the moduli and hardness of the composites increase with addition of CaCO3 content, but the tensile strength and strain at break is opposite to this; there are extreme values of the tensile yield stress and Izod impact strength at 5% and 10% of CaCO3 weight fraction, respectively. It indicates that the strength and toughness of PP can be improved to some extent when PP is filled with suitable concentration of inorganic rigid particles.
