Characterization of recycled thermoplastics-based nanocomposites: Polymer-clay compatibility, blending procedure, processing condition, and clay content effects

Nanocomposites were prepared from recycled polyolefin and clay via melt-blending. The absence/presence of compatibilizer, the blending procedure, and the processing conditions were varied to study their independent effects. First, the compatibilizers ethylene-glycidyl methacrylate (E-GMA) and/or maleic anhydride polyethylene (MAPE) were incorporated with the clay. Second, the initial one-step blending procedure was replaced with a two-step blending procedure in the preparation of the rHDPE/rPET/clay/E-GMA nanocomposite. Third, the extrusion temperature profile and screw rotation speed (30, 60, 90, 120 and 150 rpm) were altered. The overall results from XRD analysis and flexural testing showed that a combination involving the E-GMA compatibilizer, the two-step blending procedure, a high extrusion temperature and a screw rotation speed of 90 rpm was the most effective for obtaining improved clay dispersion and increasing the flexural properties. In the final investigation, various nanoclay contents (1, 3, 5, 7 and 9 wt.%) were introduced. The results showed that the flexural properties, the dispersion of the clay, the thermal stability and the flammability resistance increased with the nanoclay content.