Electrically conductive thermoplastic polyurethane/polypropylene nanocomposites with selectively distributed graphene

The electrically conductive nanocomposites composing of different concentrations (0.05-1.5 wt%) of reduced graphene oxide (RGO) in the thermoplastic polyurethane/polypropylene (TPU/PP, 55/40) matrix with a fine co-continuous structure were fabricated by solution-flocculation and melt-mixing process using a micron twin-screw extruder. Both thermodynamic and kinetic theoretical analysis predicated the preferential location of RGO in the TPU rather than PP phase. Both optical microscope and field emission scanning electron microscopy (FESEM) observations verified this theoretical dispersion predication. The homogeneous dispersion of RGO in the TPU matrix is confirmed by wide-angle X-ray diffraction (WAXD) patterns and transmission electron microscope (TEM) observation. A very low percolation threshold of 0.054 wt% was achieved owing to high conductivity of RGO and favorable double percolation effect. The tensile strength and elongation at break of the composites with RGO content of only 0.5 wt% were improved by 341.9% and 354.3%, respectively. The present work provides a guideline for an efficient, facile fabrication technique of graphene based conductive polymer nanocomposites with high electrical conductivity and improved mechanical properties. (C) 2016 Elsevier Ltd. All rights reserved.