Melt-rheological issues of polypropylene based systems with enhanced thermal conductivity

Polypropylene resins, even if widely used in several industrial applications, are still the object of research interests continuously aimed to further improve specific functional properties. In particular, it is well known that one of the weaknesses of plastic materials are their low thermal conductivity. Thus, also in the case of polypropylene (PP) resins, attention is currently paid to enhance this performance with interesting results already achieved by including conductive particles as carbon based ones. Considering that this aspect could be enhanced by developing hybrid systems containing two different fillers, giving rise to specific conductive paths, it is necessary that these modifications do not compromise the matrix processability to also ensure the production of new systems on a large scale. In this work we investigate binary and ternary systems based on a commercial grade polypropylene; for the binary composites PP is filled with multiwalled carbon nanotubes (MWCNTs) while ternary systems incorporate also a secondary filler. Preliminary results in terms of thermal conductivity and melt rheological behavior confirm that the inclusion of the secondary filler enhances the thermal properties without sacrificing the extrudability of the system.