Brittle-tough transition in PP/EPDM blends: effects of interparticle distance and tensile deformation speed

The toughness of polypropylene (PP)/ethylene-propylene-diene monomer rubber (EPDM) blends containing various EPDM contents as a function of the tensil e speed was studied. The toughness of the blends was determined from the te nsile fracture energy of the side-edge notched samples. A sharp brittle-tou gh transition was observed in the fracture energy versus interparticle dist ance (ID) curves when the crosshead speed < 102.4 mm/min. It was observed t hat the brittle-ductile transition of PP/EPDM blend occurred either by redu cing ID or by decreasing the tensile speed. The correlation between the cri tical interparticle distance and tensile deformation rate was compared with that between the critical interparticle distance and temperature for PP/EP DM blends. (C) 2000 Elsevier Science Ltd. All rights reserved.