Effect of multi-walled carbon nanotube localization on toughening mechanism and electrical properties of compatibilized PP/EOC immiscible blend

Toughness modification of polypropylene (PP), a widely used polymer in industry, is an important factor in overcoming mechanical limitations and extending its scope of application. In the present work, we utilized a combination of nanoparticle and elastomer techniques to enhance the toughness of PP. Accordingly, the nanocomposite blends, including PP, ethylene octene copolymer (EOC), and multi-walled carbon nanotubes (MWCNTs), were prepared through three different feeding methods (direct, sequential, and masterbatch). The results demonstrated that the different feeding methods significantly affect the localization and dispersion degree of the MWCNTs, and hence, toughness modification. The results also showed that the sequential is the most effective method to prepare the nanocomposites with the reinforced fracture toughness so that the addition of 2 phr MWCNTs to the PP/EOC blend leads to a high impact strength (-351.61 J/m). Because in this feeding method, most of the highly dispersed MWCNTs can be selectively located in the EOC particles as well as the interface, which can not only intensify the interfacial interactions between the two phases but also help the stress transfer and superposition of stress fields. Moreover, it was shown that in the sequential method, the MWCNTs could facilitate the creation of electrically conductive pathways as a result of nanoparticle bridging and the formation of an interconnected percolating network, therefore increasing the electrical properties.