MECHANICAL, THERMAL AND FLAMMABILITY PROPERTIES OF DOLOMITE FILLED POLYPROPYLENE COMPOSITES

Abstract

In this project, the composites of polypropylene (PP)/dolomite were prepared via extrusion and
injection moulding. Dolomite mineral was used as reinforcement in PP matrix. PP reinforced
dolomite composites with various concentrations of dolomite (5, 10 and 15 wt%) were
characterized by mechanical properties through tensile, impact and flexural test, morphological
analysis by scanning electron microscope (SEM), thermal analysis by differential scanning
calorimeter (DSC) and flammability analysis by the limiting oxygen index (LOI). The
incorporation of dolomite into PP had improved Young’s modulus while flexural modulus,
tensile, flexural and impact strengths were decreased. The incorporation of dolomite up to 15
wt% increased the stiffness of the composites in tensile mode while in three point bending
mode, 10 wt% dolomite was the optimum concentration. Tensile and flexural strength showed
a slight reduction in the values while impact strength was continuously decreased with the
addition of dolomite. SEM images showed poor interfacial adhesion between PP and dolomite,
thus supported the decreased of tensile, flexural and impact strengths. The melting and
crystallization temperatures (Tm and Tc) of the composites slightly increased with the addition
of dolomite. LOI test showed that flammability of the composites decreased with the
increasing content of dolomite.