Effect of rubber interparticle distance distribution on toughening behavior of thermoplastic polyolefin elastomer toughened polypropylene

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In this study, a blend of polypropylene (PP) and two types of thermoplastic polyolefin elastomers (TPO) were prepared by melt mixing. The TPOs were either ethylene- or propylene-based copolymer. The mechanical response and morphology of the blends were investigated using tensile and impact tests and scanning electron microscopy technique. There was significant increase in the impact strength of the TPO-modified PP, which was an outcome of fine dispersion of TPO inclusions. In particular, the blends containing PP-based TPO exhibited dramatic enhancement in toughness energy as featured by a plastic deformation in tensile test. The brittle-tough transition had several deviations from theoretical models, in which generally the interparticle distance criterion was realized as a single parameter, only controlled the transition of brittle to tough behavior. Moreover, the brittle-tough transition in tensile and impact mode tests was not coincident in the blend with a broad distribution of interparticle distance.

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