LAUSR

Abstract Graphene nanoplatelets (GNPs) consisting of few-layered graphene (FLG) with surface area of about 400 g/cm2 were prepared from expanded graphite (EG) using a shear-induced thermomechanical exfoliation process. Melt compounded composites of EG with polypropylene (PP) exhibited good filler dispersion with no visible aggregation, whereas PP-GNP composites contained finely-dispersed nanometer-scale FLG. Foams were prepared through a batch foaming process using nitrogen as the physical blowing agent, at temperatures ranging from 140 to 180 °C. The presence of EG particles and finely-dispersed GNPs promoted heterogenous nucleation, resulting in cell densities of the order of 107 cells/cm3, and a fine micro-cellular structure with an average cell diameter in the range of 20 μm–60 μm. It was further noted that the foams exhibited secondary nucleation effects stemming from the presence of very finely dispersed platelets, resulting in a secondary population of smaller cells in the range of 1 μm–10 μm. The compressive modulus of the composite foams containing 9 wt% GNPs increased five-fold compared to the neat PP foams.