Search

The V-notched Izod impact strength of poly-L-lactide composites filled with nanosized calcium carbonate was measured at room temperature. The fractal dimensions of the impact fracture surface were determined by means of the structure function method, and the relationship between the measured impact strength and the fractal dimensions of the specimen fracture surface was investigated. The results showed that the fractal dimensions of the fracture surface were within the range of about 1.76 to 1.97, all of the correlation coefficients were higher than 0.9, the strong linear correlation indicated that the fractal characterization of the fracture surface for the composites was significant, the measured impact strength increased obviously with increasing fractal dimension of the fracture surface and the correlation between them was roughly linear when the fractal dimension was more than 1.88.

The tensile properties of poly ( l -lactic acid) (PLLA) and polycaprolactone (PCL) composites filled with nanometer calcium carbonate (nano-CaCO3) were measured at room temperature and different tensile rates. With increase of the PCL weight fraction, the tensile elastic modulus, tensile strength and tensile strength at fracture for the PLLA/PCL/nano-CaCO3 composites decreased nonlinearly, and it increased slightly with increasing tensile rate. When the PCL weight fraction was less than 60%, the elongation at break for the composites increased slightly and then it increased sharply. This indicated that PCL was beneficial to improve the tensile fracture toughness of the composites.