Abstract: | The dependencies of the notched Izod impact toughness of HDPE / CaCO3 blends on CaCO3 particle concentration and particle size are analyzed. It was found that the notched Izod impact strength (S) of HDPE / CaCO3 blends depends discontinuously on CaCO3 particle concentration. A brittle-ductile transition occurs when the CaCO3 volume fraction (Vf) increases to a critical value (Vηf). Furthermore, a brittle-ductile transition master curve can be constructed by taking the matrix ligament thickness (L) into account as a parameter instead of Vf. The results show that the critical matrix ligament thickness (Lc) is a single parameter for the transition and Lc = 5.2μm for HDPE / CaCO3 blends. The impact strength, however, varies considerably with CaCO3 particle size, which shows that CaCO3 particle size is another dominating parametor for the toughness of HDPE / CaCO3 blends. © 1993 John Wiley & Sons, Inc. |