Formulation, Characterization and Optimization of the Processing Conditions of Blends of Recycled Polyethylene and Ground Tyre Rubbers: Mechanical and Rheological Analysis

Recycling represents a valid alternative to the disposal of post-consumer plastics in common landfills if it is possible to obtain new materials with good final properties compatible with practical application and, above all, by using cheap methods. In this work the possibility to produce secondary materials by blending recycled polyethylene (RPE) coming from greenhouses and post-consumer ground tyre rubber (GTR) has been studied. In particular, the preparation of these blends has been carried out in a common industrial twin screw extruder. RPE pellets and GTR powder were fed to the extruder without any other additive. Temperature, processing speed, mixing procedure and composition were changed in order to study the influence of these parameters on the rheological and mechanical properties. The results indicate that the blends show fairly good properties provided that a relatively low concentration of GTR and proper thermal conditions are adopted. A filler-like effect due to the partial carbonization of the GTR phase has also been shown especially at the highest processing temperature.