PP-EPDM BLENDS: INFLUENCE OF STRUCTURE ON BRITTLE-DUCTILE TRANSITION

摘要

The impact behavior of polypropylene and polypropylene-rubber blends have been studied as function of temperature with notched Izod and single edged notched tensile methods. Varied are the rubber concentration (0 - 40 wt %) and the rubber particle size (0.3 - 4 μm). With increasing rubber content and decreasing particle size the impact behavior is improved. The ductile deformation is accompanied with a strong temperature increase of the deformation zone and even a melting in the fracture zone. The impact enhancement process seem to be first a cavitation of the rubber particles, followed a strong plastic deformation of the matrix material ahead of the notch/crack. The deformation seem to be enhanced by a thermal blunting of the notch/crack.