Structural, elastic and thermal properties of titanium dioxide filled isotactic polypropylene

Titanium dioxide (TiO₂)-filled isotactic polypropylene (iPP) composites with various contents of TiO₂ were prepared by a locally fabricated extrusion molding machine. The extrudates were melt-pressed at 180 °C and produced as plane sheets of nearly equal thickness by rapid cooling. X-ray diffraction studies reveal a decrease of crystallinity and crystallites size as well as a change of α-, β- and γ-crystalline phases of the neat iPP to the α-form due to filler inclusion. Scanning electron micrographs taken on the fractured surface of the samples show increasing amount of voids with increasing filler content. Tensile strength, elongation-at-break (%) and glass transition temperature of the samples are found to decrease considerably with the increase in TiO₂ content, whereas microhardness decreases slightly with the filler content.