REACTIVE EXTRUSION OF POLYOLEFIN TERNARY BLENDS

Reactive extrusion of polypropylene (PP)/ethylene-propylene-diene terp olymer (EPDM)/high-density polyethylene (PE) (80/10/10 by weight) blen ds were carried out using a corotating twin-screw extruder. The effect s of peroxide and coagent concentrations and extruder rpm were studied in terms of rheological, morphological, thermal, and mechanical prope rties of the blends. Melt viscosity of the peroxide-treated blend incr eased and decreased over the untreated one depending on the amount of a coagent. Morphologically, interfaces blur with only a peroxide treat ment, and significant domain reduction was obtained when peroxide and a coagent were used together. Both T-m (crystalline melting temperatur e) and T-g (glass transition temperature) of PP increased in the blend , whereas those of PE slightly decreased. (C) 1996 John Wiley & Sons, Inc.