Rheological and electrical analysis in carbon nanofibre reinforced polypropylene composites

Two different types of carbon nanofibers (CNF) were incorporated in the same polypropylene (PP) matrix by twin-screw extrusion. The electrical characterization of both CNFs / PP composites as a function of volume fraction show different electrical performance: conducting and non-conducting. The objective of this work is to study the rheological behaviour of both composites with the aim of relating it to the electrical behaviour. The results indicate that the rheological behaviours are different, suggesting that rheology differentiates the microstructural variations responsible for the electrical performance. Furthermore, the main rheological parameters were correlated to the electrical conductivity. The results show that G´/ G´´ and G´ are the most sensitive parameters when compared to the onset of electrical percolation. Finally, in spite of the intrinsic measuring differences between electrical and rheological analysis, the two calculated thresholds are very similar: ~ 0.5 for the rheological and ~ 0.4 for the electrical.Financial support for this work has been provided by Consellería de Educación e Ordenación Universitaria, Xunta de Galicia through grant CN2011/008