Mechanical Properties and Morphology of Polypropylene Toughened with Metallocene Polymerized Polyethylene Elastomers

A remarkable breakthrough in technology for the polyolefin industry in recent years is the introduction of single-site metallocene catalysts, by which a completely new elastomer type, metallocene polymerized polyethylene (mPE) elastomers, could be developed. In this work mPE elastomer was used to replace the conventional elastomers, ethylene-propylene-diene-rubber (EPDM) and styrene-ethylene-butylene-styrene triblock copolymer (SEBS) in the toughening modification of polypropylene (PP). The influence of processing conditions and PP/elastomer ratio on the mechanical properties of PP/mPE blends were investigated. The mechanical properties of PP toughened with different elastomers were compared. The mPE in the PP/elastomer blends showed a superior low-temperature behavior and strain recovery performance in comparison to the conventional elastomers used for toughening PP. The morphology of the PP/mPE blend at blend ratio of 60/40 was analyzed by scanning electron microscopy, and the PP fibrils throughout mPE phase was observed.