Taking advantage of the functional synergism between carbon nanotubes and graphene nanoplatelets to obtain polypropylene-based nanocomposites with enhanced oxidative resistance

Carbon Nanotubes (CNT) and Graphene Nanoplatelets (GNP) were incorporated in Polypropylene (PP) as single filler (CNT = 1, 2 and 4 %wt. and GNP = 2, 4, and 6 %wt.) and in hybrid form (CNT:GNP weight ratio 2:2, 2:4 and 4:2) using a prototype miniature Twin Screw Extruder (TSE) coupled with a double slit rheological die, in order to assess in-line the extent of nanofiller dispersion and to deliver PP-based nanocomposites with enhanced thermo-oxidative stability. The morphological, electrical and mechanical properties, as well as the resistance to thermal and photo degradation of the composites containing single nanofillers (PP/CNT and PP/GNP) were compared with those of hybrid PP based nanocomposites (PP/CNT:GNP). The results highlight that the presence of the two carbonaceous nanofillers exerts a positive synergic effect on the nanocomposite properties. Moreover, the radical scavenging role of the carbonaceous nanofillers was investigated under thermo-mechanical, thermo- and photo degradation conditions, the results confirming that aspect ratio, loading and dispersion level of the filler play a determinant role in the nanocomposite durability.