Morphology and mechanical properties of PP/LLDPE blends and ternary PP/LLDPE/NANO-CaCO3 composites

Mechanical and morphological properties of polypropylene (PP)/linear low density polyethylene (LLDPE)/ nano-sized calcium carbonate ternary composites were prepared using a twin-screw extruder. Modification of the filler nano-particle surface was pretreated with stearic acid and of the PP/LLDPE interface by melting high crystallizable, high density polyethylene. In this research, effects of modified linear low density polyethylene (LD) and nano-CaCO₃ weight percentage on tensile strength, Young’s modulus and impact absorbed energy of composites were investigated. In addition, effect of the interaction between filler particles and polymer matrix was studied. Effect of quantity of microcracks on tensile properties of the composites was also discussed. Effect of nano-CaCO₃ and LD on the quantity of microcracks and impact-fractured surface of PP composites was studied by scanning electron microscope (SEM). The impact-fractured surface morphologies were characterized by SEM to clarify the possible mechanisms for improving the fracture resistance.

Keywords

Microcrack; Impact strength; Nanocomposites; Calcium carbonate.