Fracture Behavior Of Polypropylene/Elastorner Blends

In this paper, effort has been undertaken to study the fracture behavior of thermoplastic/elastomer (PP/SBS) dynamically vulcanized blends by analyzing the EWF test results. PP/SBS blends were prepared with concentrations of SBS of 15, 30 and 40 wt%. Deeply double edged notched tension (DDENT) specimens were cut from injection molded plaques for fracture testing. It should be noted that the incorporation of SBS to PP seems to enhance fracture toughness, thus the specific essential work (we) increases with elastomer content. The elastomer particles contribute to the energy dissipation at the fracture surface and in the outer plastic zone in which various types of deformation might have been at work. Also, it seems that the fracture toughness value levels-off from 30 wt% rubber on. In addition, the incorporation of SBS triggers a considerable plastic deformation, since the non-essential work (beta wp) increases compared to the value of pure PP. Nonetheless, a decrease in beta wp is present with increasing amount of rubber. So the EWF method revealed that the dynamic vulcanization method can impair fracture resistance to PP/SBS blends.