Structure-property relationships in polypropylene/poly(ethylene-co-octene)/multiwalled carbon nanotube nanocomposites prepared via a novel eccentric rotor extruder

In this work, polypropylene/poly(ethylene-co-octene)/multiwalled carbon nanotube (PP/POE/MWCNT) nanocomposites with different contents of MWCNTs were prepared by an eccentric rotor extruder to obtain engineering materials with excellent performance capability. Microphotographs (scanning electron microscopy and transmission electron microscopy) and dynamic mechanical analysis indicate that the MWCNTs were well dispersed in the polymer matrix under the elongation flow. The crystallization behavior was explored by X-ray diffraction and differential scanning calorimetry. The results show that MWCNTs promote heterogeneous nucleation and improve the To, Tc and Te values of the composites. On the basis of the rheology analysis, the complex viscosity of the PP/POE/MWCNT composites increased and formed an obvious Newton plat in the low-frequency range; both the G′ and G″ of all the samples increased monotonically, and a percolation threshold appeared for 1 wt% MWCNTs. Thus, the mechanical properties of the nanocomposites prepared under an elongation flow lead to an effective strengthening of PP/POE better than under a shear flow. This work provides a novel method based on elongational rheology to prepare engineered materials that possess excellent performance capabilities.