Theoretical models for prediction of mechanicalbehaviour of the PP/EPDM nanocomposites fabricatedby friction stir process

In this study, thermoplastic polyolefn elastomeric (TPO) nanocomposites were fabricated by friction stir processing. The effect of different pin geometries on clay dispersion and mechanical properties of the TPOnanocomposite reinforced with 3% wt nanoclay has been frst investigated. The optimum pin geometry namelythreaded cylindrical pin was then used to fabricate the nanocomposites containing 3, 5 and 7 wt% nanoclay.The results showed that increase in the clay content increased the tensile strength and tensile modulus of thenanocomposite from 15.8 to 22.76 MPa and 568 to 751 MPa, respectively. The experimental stress – strain curvesof nanocomposites were compared with eight constitutive models including Mooney – Rivlin, the second-orderpolynomial, Neo – Hookean, Yeoh, Arruda – Boyce, Van der Waals and the third- and sixth-order Ogden. Thecomparisons showed that there was an agreement between the experimental data and the sixth-order Ogden model.Three micromechanical models Halpin – Tsai, inverse rule of mixture and linear rule of mixture were applied toinvestigate the Young’s modulus of nanocomposites. Because of the signifcant difference between the Young’smodulus obtained from these models and the ones obtained from experimental data, a modifying factor was used toimprove the theoretical predictions obtained from the models. Polyolefns J (2017) 4: 99-109

Keywords:

geometry , friction stir process , nanocomposite , clay , mechanical behavior