title: Structure-property relationships in heterophasic thermoplastic elastomers filled with montmorillonite.
abstract: Polypropylene (PP)/ethylene-propylene rubber (EPR)/Montmorillonite ternary nanocomposites with a phase separated morphology were studied in this work. Wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to investigate the samples. One of the aim of this work was to separate the effects of rubber and clay content on the structure, morphology and mechanical properties of the samples. The presence of clay favored the formation of gamma phase and disrupted the lamellar framework. Clay had moreover a major role in shaping the phase separated morphology of the samples. Atomic Force Microscopy showed that the shear exerted by the clay layers was key for inducing a shish kebab morphology in the polymer matrix. Rubber content decreased the degree of crystallinity at a crystalline cell level and induced the formation of a double population of lamellar stacks. The mechanical properties of the samples primarily depended on rubber content, and they were secondarily tuned by the effect of clay. This synergistic effect allowed to obtain composites with increased stiffness, ductility and toughness, oppositely to what is frequently found.
authors: Dipartimento di Scienze Chimiche, Università di Padova, and INSTM Research Unit, via Marzolo 1, 35131 Padova, Italy.
authors: Valerio
authors: V
authors: Causin
authors: Carla
authors: C
authors: Marega
authors: Roberta
authors: R
authors: Saini
authors: Ramesh
authors: R
authors: Neppalli
authors: Giuseppe
authors: G
authors: Ferrara
authors: Rameshwar
authors: R
authors: Adhikari
authors: Antonio
authors: A
authors: Marigo