Dispersion of carbon nanotubes in polypropylene via multilayer coextrusion: Influence on the mechanical properties

Multilayer coextrusion was used to disperse Carbon Nanotubes (CNT) in polypropylene (PP). The dilution of commercially available masterbatches using a twin-screw extruder was first applied to produce several formulations, which were then mixed with PP using a multilayer coextrusion device to obtain films or pellets with CNT concentrations between 0.1 and 1%wt. The influence of the specific mechanical energy (SME) during the dilution step, of the addition of a compatibilizer, and of the multilayer tool on the CNT dispersion within the matrix was highlighted. The effect of the dispersion on the thermo-mechanical properties of the resulting materials was studied. We showed notably that films containing 0.2%wt CNT, 1%wt of PPgAm, prepared at high SME presented a Young's modulus increase of 25-30% without significant decrease in the elongation at break. These results, using low amounts of CNT and industrially available devices, may show a new path for producing nanocomposites. (C) 2013 Elsevier Ltd. All rights reserved.