title: Liquid-State and Solid-State Properties of Nanotube/Polypropylene Nanocomposites Elaborated via a Simple Procedure.
abstract: Non-modified Multiwalled Carbon Nanotubes (MWCNT) and polypropylene (PP) in absence of compatibilizer have been chosen to elaborate MWCNT/PP nanocomposites using a simple melt-mixing dispersing method. Calorimetry results indicate little effect of MWCNTs on crystallinity of PP, revealing not much interaction between nanotubes and PP chains, which is compatible with the employed manufacturing procedure. In any case, a hindering of polymer chains motion by MWCNTs is observed in the molten state, using oscillatory flow experiments, and a rheological percolation threshold is determined. The percolation limit is not noticed by Pressure-Volume-Temperature (PVT) measurements in the melt, because this technique rather detects local motions. Keeping the nanocomposites in the molten state provokes an electrical conductivity increase of several orders of magnitude, but on ulterior crystallization, the conductivity decreases, probably due to a reduction of the ionic conductivity. For a concentration of 2% MWCNTs, in the limit of percolation, the conductivity decreases considerably more, because percolation network constituted in the molten state is unstable and is destroyed during crystallization.
authors.affiliation: Polymer Science and Technology Department and Polymer Institute POLYMAT, Faculty of Chemistry and J. M. Korta Building, University of the Basque Country (UPV/EHU), P.O. Box 1072, E-20080 San Sebastian, Basque Country, Spain. arrate.huegun@ehu.es.
authors.forename: Arrate
authors.initials: A
authors.lastname: Huegun
authors.affiliation: Polymer Science and Technology Department and Polymer Institute POLYMAT, Faculty of Chemistry and J. M. Korta Building, University of the Basque Country (UPV/EHU), P.O. Box 1072, E-20080 San Sebastian, Basque Country, Spain. mercedes.fernandez@ehu.es.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Fernández
authors.affiliation: Department of Physics of Materials, Faculty of Chemistry, University of the Basque Country (UPV/EHU), P.O. Box 1072, E-20080 San Sebastian, Basque Country, Spain. juanjo.pena@ehu.es.
authors.forename: Juanjo
authors.initials: J
authors.lastname: Peña
authors.affiliation: Polymer Science and Technology Department and Polymer Institute POLYMAT, Faculty of Chemistry and J. M. Korta Building, University of the Basque Country (UPV/EHU), P.O. Box 1072, E-20080 San Sebastian, Basque Country, Spain. mariaeugenia.munoz@ehu.es.
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: Muñoz
authors.affiliation: Polymer Science and Technology Department and Polymer Institute POLYMAT, Faculty of Chemistry and J. M. Korta Building, University of the Basque Country (UPV/EHU), P.O. Box 1072, E-20080 San Sebastian, Basque Country, Spain. antxon.santamaria@ehu.es.
authors.forename: Antxon
authors.initials: A
authors.lastname: Santamaría
keywords: carbon nanotubes; conducting polymers; crystallization; electrical percolation; rheological percolation; rheology