Mechanical Properties and Morphology of Poly(l-Lactic acid)/Nano-CaCO3 Composites

The tensile and impact properties of poly(l-lactic acid) composites filled with nanometer calcium carbonate (nano-CaCO3) were measured at room temperature. The results showed that the tensile elastic modulus increased roughly linearly while the tensile yield strength, tensile fracture strength and tensile elongation at break (δb) decreased nonlinearly with increasing the nano-CaCO3 weight fraction (Wf); when Wf was constant, the δb increased with increasing tensile rates. Both the V-notched Izod impact strength and V-notched Charpy impact strength showed the non-linear increase with increasing Wf. The impact fracture surface was observed by means of a scanning electronic microscope to understand the toughening mechanisms.