Physical-mechanical and thermal properties of polyethylene thoughned with submicron BaSO4 particles

The mechanical and thermal behaviour and the morphology of High-Density Polyethylene (HDPE), filled with different types of Barium Sulfate (BaSO4) submicron particles have been examined. Composites with a filler content in the range 5-15 vol% were obtained with a twin screw mixer-single screw extruder and then analyzed by means of DSC, scanning electron microscopy (SEM) and tensile and Charpy impact tests. The effect of different surface treatment of filler particles on the composite properties has been studied. The results indicate that the addition of BaSO4 particles leads to slight increase in Young’s modulus and to a decrease in the yield stress independently of surface treatment. The fracture resistance tests have demonstrated a strong influence of filler content and surface agents on impact parameters. The use of BaSO4 filler appears to induce a good toughening of HDPE, especially at low volume content, while surface agents reduce particle agglomeration and decrease the adhesion between filler and polymer matrix.