Toughening of Propylene‐ethylene Copolymer/Calcium Carbonate Composites with High‐Density Polyethylene

Propylene‐ethylene copolymer/calcium carbonate (CaCO₃) composites (weight ratio=50/50) toughened with high density polyethylene (HDPE) were prepared using a twin‐screw extruder; the HDPE content in composites was in the range of 0–4 wt.%. The notched impact strength of propylene‐ethylene copolymer/CaCO₃ composites with 1.5 wt.% HDPE was 46% higher than that of propylene‐ethylene copolymer/CaCO₃ composites. Differential scanning calorimetry (DSC) experiments showed that good miscibility between propylene‐ethylene copolymer and HDPE enhanced the interpenetration of the macromolecules located in the interface. It was shown that debonding of the small HDPE particles within the propylene‐ethylene copolymer matrix resulted in the formation of small voids; the subsequent plastic deformation of the propylene‐ethylene copolymer matrix next to the voids thinned the ligaments and led to large energy consumption.