Functionalized graphene sheets filled isotactic polypropylene nanocomposites

The graphene oxide sheets (GOs) reacted with 4,4′-diphenylmethane diisocyanate (MDI) and then stearic acid to form the functionalized graphene sheets (FGs), in order to improve their compatibility with isotactic polypropylene (iPP). The iPP incorporated with FGs were adequately mixed in a Haaker mixer and then compression molded to obtain the iPP/FGs nanocomposites. The crystallization, thermal stability and mechanical properties of the nanocomposites together with iPP/graphite sheets (Gs) and iPP/GOs composites were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and tensile test. The FGs achieved good dispersion with exfoliated and intercalated nanostructure and strong interfacial adhesion with iPP, which made the nanocomposites have a significant enhancement of thermal stability and mechanical properties at low FGs loadings.