Influence of mixing protocol on the morphology and mechanical properties of PP/SEBS/MMT and PP/SEBS/PPgMA/MMT blends

PP/SEBS blends containing MMT and MMT/PPgMA were obtained by extrusion using different mixing protocols. Specimens were subjected to mechanical testing (tensile, flexural and impact tests) and blend morphologies were characterized by SEM, TEM and XRD. MMT and PPgMA incorporation and the mixing protocol were shown to affect morphology (droplet size), whereas MMT location resulted in variations in nanocomposite mechanical properties. The presence of PPgMA attracted the organoclay towards the matrix phase due to the interaction between the functional groups at the MMT surface layers and the maleic anhydride groups. Nanocomposites with or without PPgMA obtained in one step presented higher stiffness, while nanocomposites obtained in two steps presented higher impact strength.