Graphene oxide and graphene hybrid nanocomposites based on compatibilized PP/PTW/EVA: effect of nanofiller and compatibilizer on the modeling of viscoplastic behavior

In the present contribution, a series of elastomer nanocomposites based on PP/EVA (polypropylene/ethylene vinyl acetate copolymer) immiscible blends which are compatibilized with PTW (n-butyl acrylate glycidyl methacrypoles terpolymer) and addition of graphene and graphene oxide were prepared with melt mixing method. In nano-dispersed filler containing rubbers, mechanical properties of nanocomposites are dictated by the characteristics of interphase as well as the rubber-nanoparticle interactions at the interface. The Bergstrom-Boyce model was evaluated to approximate stress-strain behavior of nanocomposites. In addition to mechanical properties, rheological properties and in particular, creep behavior were also evaluated and analyzed for different samples. It was shown that the incorporation of nanofillers in the presence of PTW compatibilizer reduces the size of droplets of EVA disperse phase, but this reduction is more dramatic in the case of nanocomposites containing graphene oxide. The TEM image showed that nanocomposites containing compatibilizer and nanofillers changed the localization of nanofillers and led to the migration them to interface of EVA and PP. The stress-strain behavior of prepared nanocomposites is closely related to TEM and SEM micrographs. The results extracted from the Bergstrom-Boyce model that compounds containing PTW illustrated the better adaptation in comparison to another samples. The creep behavior of samples showed that by incorporation of PTW and increasing the concentration of graphene and graphene oxide nanoplatelets to the PP/EVA, the creep and recovery compliance show lower amounts for PP/EVA.