Morphological characterization of single-walled carbon nanotubes-PP composites

Polypropylene matrix composites reinforced with single-walled nanotubes (PP-SWNTs) were produced using different nanotubes concentrations. The characterization of these new materials was performed by differential scanning calorimetry and Raman spectroscopy in order to obtain information on the matrix–nanotube interaction, on the crystallization kinetics of PP and, especially, on the macrostructure and organization of the nanotubes in the composite. On the one hand, the results confirm the expected nucleant effect of nanotubes on the crystallization of polypropylene but on the other, this effect is not linearly dependent on the SWNTs content, showing a saturation of the nucleant effect at low nanotube concentrations. Raman spectroscopy is successfully applied to demonstrate that in the composite films, the crystallization kinetics is strongly affected by the distance between the nanotube bundles as a consequence of a different intercalation of the polymer.