MELT RHEOLOGY, MORPHOLOGY, AND MECHANICAL-PROPERTIES OF THERMOPLASTICRUBBER BLENDS/

This work reports on the melt rheology, morphology, mechanical propert ies, and accelerated UV aging resistance of binary blends of polypropy lene (PP) and high-density polyethylene (HDPE) thermoplastics with two kinds of rubber: ethylene-propylene-diene terpolymer (EPDM) and polyi soprene rubber (IR). The blends were also formulated with calcium carb onate (CaCO3) filler, and the rubber was partially crosslinked with di cumyl peroxide (DCP). The blends were compared with a commercial therm oplastic rubber (TPR). The effect of the thermoplastic/rubber ratio, a nd the addition of CaCO3 and DCP on the melt rheology, morphology, and mechanical properties was investigated, looking for a TPR with good m echanical performance, ease of processing, and aging resistance. An in crease in mechanical properties and melt viscosity with the rubber and peroxide content on the blend was observed. On the other hand, the Ca CO3 incorporation reduces the elongation and increases the melt viscos ity of the blend. The morphology of the blends examined by scanning el ectron microscopy (SEM) revealed that the adding the filer improved th e dispersion of EPDM onto the PE and PP.