The effects of pulverized cross-linked hdpe granules on the rheological and mechanical properties of HDPE

Crushed crosslinked polyethylene(XLPE) scraps of 1.5 similar to 2.0 cm in size were pulverized and separated into two groups according to granule sizes, namely 1.0 similar to 0.59 mm and 0.59 similar to 0.25 mm in diameter. These granules were, then, blended with high-density polyethylene (HDPE) up to 40% by weight, using a Banbury type mixer and a single screw extruder. The prepared pellets were examined in terms of processability and mechanical properties. Injection molding was possible without a loss in an injection cycle-time even for a sample blended with XLPE granules up to 40 wt%. It was also found that the impact strength of blended sample at room temperature increased with the XLPE granule concentration. However, the impact strength at cryogenic temperature(-30 degrees C) showed a maximum at 20 wt% XLPE concentration. The HDPE/XLPE composites in the presence of maleic anhydride(MAH) and dicumyl peroxide (DCP) showed much improved impact strength without any deterioration of other mechanical properties. Data on processabilities and mechanical properties of the composite samples suggest that the XLPE can be recycled as a useful impact modifier for HDPE.