Effect of processing parameters on morphology and tensile properties of PP/EPDM/organoclay nanocomposites fabricated by friction stir processing

Nanocomposites-based on polypropylene (PP), ethylene-propylene diene monomer (EPDM) and Cloisite 15A have wide applications in automotive and aerospace industries and medical apparatus due to their excellent mechanical, thermal and chemical properties. In this study, a nanocomposite of PP/EPDM/nanoclay containing PP (77 wt%), EPDM (20 wt%) and nanoclay (3 wt%) was fabricated by friction stir processing (FSP) method. X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and tensile testing were performed to determine the morphology and tensile properties of this nanocomposite. The Box-Behnken design was applied to investigate the effect of the process parameters such as tool rotational speed, traverse speed and shoulder temperature on the tensile properties of the nanocomposite. The results showed that the tensile strength increased from 15.8 to 18.2 MPa with increasing the tool rotational speed and shoulder temperature while the elongation-at-break dropped from 46 to 22 %. A maximum tensile strength of 17.6 MPa and a minimum elongation-at-break of 26 % were obtained at the traverse speed of 40 mm/min when the rotational speed and shoulder temperature were at the central levels themselves. The prediction models showed that when the tool rotational speed, traverse speed and shoulder temperature were set, in the given order, as 1200 rpm, 45.65 mm/min and 113.65 degrees C, a simultaneous maximization of tensile strength of 16.03 MPa and elongation-at-break of 46.41 % was obtained.