Yielding behaviour of thermoplastic/elastomer blends cured by gamma irradiation

Mechanical blends of thermoplastic medium density polyethylene (MDPE) and e lastomeric ethylene propylene diene monomer (EPDM) have been prepared with a fixed composition of 60/40 wt%. They have been used either in their gum f orm or loaded with two different reinforcing fillers, high abrasion furnace (HAF) carbon black or precipitated SiO2 (Hi Sil) of concentration 25-100 p hr (parts per hundred parts of resin) with respect to the blend. Curing was achieved by gamma irradiation. Yielding properties (yield stress, yield st rain and cold drawing) have been followed as a function of irradiation dose for different blend compositions. Yield stress values increased with irrad iation dose and with the content of the reinforcing filler, but yield strai n and cold drawing values decreased with irradiation dose and also with the filler content. The data obtained reveal that Hi Sil is more effective as a reinforcing filler, and the prepared blends are suitable for load-bearing applications. (C) 2001 Society of Chemical Industry.