Synergetic effect of polyolefin elastomer and CaCO3 particle on ternary nano-composite (polypropylene/polyolefin elastomers/calcium carbonate) behavior

The mechanical and toughening properties of ternary nano-composites (polypropylene/polyolefin elastomer/calcium carbonate) are investigated. Blends of polypropylene (PP)/ethylene-alpha olefin copolymer (polyolefin elastomer)/nano calcium carbonate were prepared through a two-step process. Stearic acid-treated CaCO3 (denoted CC322) and non-treated CaCO3 (denoted CC31) were used at content of 1%, 3%, and 5%. Two polyolefin elastomers (POE), ethylene-butene and ethylene-octene copolymers at 5wt% were also used to adjust the phase structure of the ternary nano-composites. Tension surface measurements were correlated to morphological observations. Two phase structures were found: (1) treated calcium carbonate contributes to form the core-shell structure (2) non-treated calcium carbonate builds filler-network structure for the two POE. The mechanical properties of nano-composites were investigated using Izod impact and tensile tests. The influence of the morphologies on the impact strength and toughness of the nano-composites was studied. The formation of a filler-network structure was found to be a key for the toughness enhancement. A positive and synergic effect was found using ethylene-octene copolymer and non-treated calcium carbonate.