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

The authors would like to thank PSA for funding this research and providing some of the materials used in this study. We also would like to thank R. Glénat, P. Soria, E. Dandeu, A. Grand- montagne and A. Dubruc for their help in the preparation and the optical and mechanical characterizations of the samples presented in this study.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 thermomechanical 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 25e30% 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